Electrophysiological actions of somatostatin on the atrioventricular junction in sinus rhythm and reentry tachycardia.

PubMed Central

Webb, S C; Krikler, D M; Hendry, W G; Adrian, T E; Bloom, S R

1986-01-01

Because somatostatin, a neuroregulatory peptide, is found in abundance in the atria and atrioventricular node, its electrophysiological and antiarrhythmic properties were compared with those of verapamil in ten patients with paroxysmal atrioventricular tachycardia. During sinus rhythm, intravenous somatostatin slowed the heart rate whereas verapamil increased it. Though both agents prolonged atrioventricular conduction time and refractoriness, verapamil was more potent. They were equally effective at terminating reentry atrioventricular tachycardia, restoring sinus rhythm in six of seven patients. Whereas verapamil consistently blocked conduction in the atrioventricular node, somatostatin usually induced ventricular extrasystoles at the time of conversion. Somatostatin may have physiological importance in the neurohumoral control of cardiac impulse formation and conduction. PMID:2875723

Electrophysiological actions of somatostatin on the atrioventricular junction in sinus rhythm and reentry tachycardia.

PubMed

Webb, S C; Krikler, D M; Hendry, W G; Adrian, T E; Bloom, S R

1986-09-01

Because somatostatin, a neuroregulatory peptide, is found in abundance in the atria and atrioventricular node, its electrophysiological and antiarrhythmic properties were compared with those of verapamil in ten patients with paroxysmal atrioventricular tachycardia. During sinus rhythm, intravenous somatostatin slowed the heart rate whereas verapamil increased it. Though both agents prolonged atrioventricular conduction time and refractoriness, verapamil was more potent. They were equally effective at terminating reentry atrioventricular tachycardia, restoring sinus rhythm in six of seven patients. Whereas verapamil consistently blocked conduction in the atrioventricular node, somatostatin usually induced ventricular extrasystoles at the time of conversion. Somatostatin may have physiological importance in the neurohumoral control of cardiac impulse formation and conduction.

Estimation of 3-D conduction velocity vector fields from cardiac mapping data.

PubMed

Barnette, A R; Bayly, P V; Zhang, S; Walcott, G P; Ideker, R E; Smith, W M

2000-08-01

A method to estimate three-dimensional (3-D) conduction velocity vector fields in cardiac tissue is presented. The speed and direction of propagation are found from polynomial "surfaces" fitted to space-time (x, y, z, t) coordinates of cardiac activity. The technique is applied to sinus rhythm and paced rhythm mapped with plunge needles at 396-466 sites in the canine myocardium. The method was validated on simulated 3-D plane and spherical waves. For simulated data, conduction velocities were estimated with an accuracy of 1%-2%. In experimental data, estimates of conduction speeds during paced rhythm were slower than those found during normal sinus rhythm. Vector directions were also found to differ between different types of beats. The technique was able to distinguish between premature ventricular contractions and sinus beats and between sinus and paced beats. The proposed approach to computing velocity vector fields provides an automated, physiological, and quantitative description of local electrical activity in 3-D tissue. This method may provide insight into abnormal conduction associated with fatal ventricular arrhythmias.

Analysis of the O-wave in acute right ventricular apex impedance measurements with a standard pacing lead in animals.

PubMed

Järverud, K; Ollmar, S; Brodin, L A

2002-09-01

Modern pacemakers (implantable devices used for maintaining an appropriate heart rate in patients) can use an intracardiac ventricular impedance signal for physiological cardiac stimulation control. Intracardiac ventricular impedance from nine animal subjects is analysed and presented (seven sheep: 49.0 +/- 6.5 kg, sinus rhythm 100.3 +/- 16.5 beats min(-1), average impedance 629.8 +/- 72.6 ohms; and two dogs: 30 kg each, sinus rhythm 86.0 beats min(-1), 862.1 ohms and 134.0 beats min(-1), 1114.6 ohms, respectively). The averaged curve and standard deviation curve of the impedance in sinus rhythm were analysed in MATLAB to clarify and study consistent impedance shape over one heart cycle. In eight of nine (89%) animal subjects, a consistent impedance slope change (notch) was observed in the early stage of the cardiac filling phase. This result was reproduced in an additional subject with simultaneous echocardiographical measurements of mitral valve blood flow. The notch occured soon after rapid early filling (E-wave in mitral flow) but prior to ventricular filling caused by atrial contraction, indicating that the impedance notch was caused by rapid ventricular filling and that it might be a sensed feature of diagnostic value. The intracardiac impedance notch in the present study had similar features to the non-invasive transthoracic impedance O-wave reported by others, and it is shown here that an O-wave is found in intracardiac impedance signals, strongly suggesting that the non-invasive O-wave is caused by cardiac events.

Hyperthyroidism and the management of atrial fibrillation.

PubMed

Shimizu, Taeko; Koide, Saori; Noh, Jaduk Yoshimura; Sugino, Kiminori; Ito, Kohichi; Nakazawa, Hiroe

2002-06-01

Atrial fibrillation is often induced in patients with hyperthyroidism and may trigger heart failure. Its prevalence and outcome were examined to obtain up-to-date information. Persistent atrial fibrillation was observed in approximately 1.7% of new hyperthyroid patients. It occurs more frequently in males (2.86%) than in females (1.36%), even though the number of male hyperthyroid patients is only one fifth of female patients. The rate increased with age, being 8% in the patients older than 70 years old. The initial treatment is to control the heart rate with routine pharmacologic therapy and to start antithyroid therapy as quickly as possible. Attempted cardioversion should be deferred until approximately the fourth month of maintaining a euthyroid state, because more than 56% of atrial fibrillation spontaneously reverts to sinus rhythm when the thyroid hormone levels start to decline. Elective cardioversion for those whose atrial fibrillation persists is highly effective and sinus rhythm maintenance rates were 56.7% and 47.6% at the 10th and the 14th year, respectively, even though the duration of atrial fibrillation prior to cardioversion was extremely long (35.0 +/- 29.0 months).

Interatrial septal motion as a novel index to predict left atrial pressure.

PubMed

Masai, Kumiko; Kishima, Hideyuki; Takahashi, Satoshi; Ashida, Kenki; Goda, Akiko; Mine, Takanao; Asakura, Masanori; Ishihara, Masaharu; Masuyama, Tohru

2018-01-22

We investigated whether the interatrial septal (IAS) motion of each heartbeat which is observed by transesophageal echocardiography reflects left atrial pressure (LAP) in patients with atrial fibrillation (AF). We studied 100 patients (70 males, age 67 ± 9 years) who underwent catheter ablation for AF. The amplitude of IAS motion was measured using M-mode and averaged for five cardiac cycles. Left and right atrial pressures, the left to right atrial pressure gradient were directly measured during the catheter ablation. In patients with sinus rhythm during measurement, elevated mean LAP, larger maximum left to right atrial pressure gradient, and greater left atrial emptying fraction were associated with IAS motion. The optimal cut-off value of the IAS motion for predicting high LAP (mean LAP > 15 mmHg) was 8.5 mm (sensitivity 100%, specificity 70.1%) in patients with sinus rhythm during pressure measurement. In addition, all patients were divided into 6 groups based on rhythm during measurement and cutoff value of IAS motion. In patients with sinus rhythm during measurement, low IAS motion group had a highest prevalence of elevated LAP compared with high IAS motion group (64 vs. 0%, P < 0.0001). The amplitude of interatrial septal motion during sinus rhythm reflects left atrial pressure in patients with atrial fibrillation. Interatrial septal motion could be a new index to predict elevated left atrial pressure.

Systematic analysis of ECG predictors of sinus rhythm maintenance after electrical cardioversion for persistent atrial fibrillation.

PubMed

Lankveld, Theo; de Vos, Cees B; Limantoro, Ione; Zeemering, Stef; Dudink, Elton; Crijns, Harry J; Schotten, Ulrich

2016-05-01

Electrical cardioversion (ECV) is one of the rhythm control strategies in patients with persistent atrial fibrillation (AF). Unfortunately, recurrences of AF are common after ECV, which significantly limits the practical benefit of this treatment in patients with AF. The objectives of this study were to identify noninvasive complexity or frequency parameters obtained from the surface electrocardiogram (ECG) to predict sinus rhythm (SR) maintenance after ECV and to compare these ECG parameters with clinical predictors. We studied a wide variety of ECG-derived time- and frequency-domain AF complexity parameters in a prospective cohort of 502 patients with persistent AF referred for ECV. During 1-year follow-up, 161 patients (32%) maintained SR. The best clinical predictor of SR maintenance was antiarrhythmic drug (AAD) treatment. A model including clinical parameters predicted SR maintenance with a mean cross-validated area under the receiver operating characteristic curve (AUC) of 0.62 ± 0.05. The best single ECG parameter was the dominant frequency (DF) on lead V6. Combining several ECG parameters predicted SR maintenance with a mean AUC of 0.64 ± 0.06. Combining clinical and ECG parameters improved prediction to a mean AUC of 0.67 ± 0.05. Although the DF was affected by AAD treatment, excluding patients taking AADs did not significantly lower the predictive performance captured by the ECG. ECG-derived parameters predict SR maintenance during 1-year follow-up after ECV at least as good as known clinical predictors of rhythm outcome. The DF proved to be the most powerful ECG-derived predictor. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Mid-Term Results of Surgical Treatment of Atrial Fibrillation in Valvular Heart Disease Assesed by Speckle Tracking Echocardiography

PubMed Central

Lorenzo, Natalia; Mendez, Irene; Taibo, Mikel; Martinis, Gianfranco; Badia, Sara; Reyes, Guillermo; Aguilar, Rio

2018-01-01

Background Atrial fibrillation frequently affects patients with valvular heart disease. Ablation of atrial fibrillation during valvular surgery is an alternative for restoring sinus rhythm. Objectives This study aimed to evaluate mid-term results of successful atrial fibrillation surgical ablation during valvular heart disease surgery, to explore left atrium post-ablation mechanics and to identify predictors of recurrence. Methods Fifty-three consecutive candidates were included. Eligibility criteria for ablation included persistent atrial fibrillation <10 years and left atrium diameter < 6.0 cm. Three months after surgery, echocardiogram, 24-hour Holter monitoring and electrocardiograms were performed in all candidates who maintained sinus rhythm (44 patients). Echo-study included left atrial deformation parameters (strain and strain rate), using 2-dimensional speckle-tracking echocardiography. Simultaneously, 30 healthy individuals (controls) were analyzed with the same protocol for left atrial performance. Significance was considered with a P value of < 0.05. Results After a mean follow up of 17 ± 2 months, 13 new post-operative cases of recurrent atrial fibrillation were identified. A total of 1,245 left atrial segments were analysed. Left atrium was severely dilated in the post-surgery group and, mechanical properties of left atrium did not recover after surgery when compared with normal values. Left atrial volume (≥ 64 mL/m2) was the only independent predictor of atrial fibrillation recurrence (p = 0.03). Conclusions Left atrial volume was larger in patients with atrial fibrillation recurrence and emerges as the main predictor of recurrences, thereby improving the selection of candidates for this therapy; however, no differences were found regarding myocardial deformation parameters. Despite electrical maintenance of sinus rhythm, left atrium mechanics did not recover after atrial fibrillation ablation performed during valvular heart disease surgery. PMID:29561964

Platelet reactivity and mean platelet volume as risk markers of thrombogenesis in atrial fibrillation.

PubMed

Makowski, Marcin; Smorag, Ireneusz; Makowska, Joanna; Bissinger, Andrzej; Grycewicz, Tomasz; Paśnik, Jarek; Kidawa, Michal; Lubiński, Andrzej; Zielińska, Marzenna; Baj, Zbigniew

2017-05-15

Atrial fibrillation (AF) is associated with increased risk of thromboembolic complications. One of the markers of the increased risk of hypercoagulable state is platelet hyperreactivity. The aim of the study was to assess impact of arrhythmia on platelet reactivity. The study included 36 (mean age 48,3; range 21-60) male patients with lone atrial fibrillation, with exclusion of concomitant diseases known to trigger hypercoagulable state. The AF patients underwent cardioversion to restore sinus rhythm and were subsequently under observation for 1month. Echocardiography, ECG and blood collection was performed before cardioversion (T0) and 4weeks after successful cardioversion (T1). During the study period patients have been contacted and examined every week and 24h ECG monitoring was performed. Platelet reactivity was assessed based on changes of CD62 and CD42b expression on platelet surface after stimulation with thrombin. Also changes in MPV were assessed. In all patients sinus rhythm was maintained at the end of the study period, however in 14 patients recurrences of AF were observed, confirmed by 24h ECG monitoring (atrial fibrillation recurrence group - AFR) and 22 patients maintained sinus rhythm throughout the whole study period (SR group). Mean fluorescence intensity (MFI) of CD62 on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (48.04±22.42 vs 41.47±16.03; p<0.01). Also MFI of CD42b on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (22.16±10.82 vs 12.06±5.99; p<0.0001). Platelets reactivity estimated by CD 62 expression in SR group decreased significantly after 4weeks observation (58.01±15.26 vs 46.57±13.44; p<0.001) opposite to AFR group 35.66±21.87 vs 34.54±16.4; p-ns). Moreover there were significant differences between basal reactivity during AF between SR and AFR groups (58.01±15.26 vs 35.66±21.87; p-0.01). MFI of CD42b on thrombin stimulated platelets decreased significantly both in AFR and SR groups (22.05±11.36 vs 13.8±6.03; p<0.001 and 21.87±14.18 vs 10.04±5.09; p<0005). MPV decreased significantly 4weeks after electrical cardioversion as compared to T0 (8.81±0.19 vs 8.42±0.14; p<0.0001). The changes of platelet reactivity to thrombin observed after restoration of sinus rhythm in patients prove that arrhythmia intrinsically leads to increased reactivity of platelets. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation.

PubMed

Lafuente-Lafuente, Carmelo; Valembois, Lucie; Bergmann, Jean-François; Belmin, Joël

2015-03-28

Atrial fibrillation is the most frequent sustained arrhythmia. Atrial fibrillation frequently recurs after restoration of normal sinus rhythm. Antiarrhythmic drugs have been widely used to prevent recurrence, but the effect of these drugs on mortality and other clinical outcomes is unclear. This is an update of a review previously published in 2008 and 2012. To determine in patients who have recovered sinus rhythm after having atrial fibrillation, the effects of long-term treatment with antiarrhythmic drugs on death, stroke, embolism, drug adverse effects and recurrence of atrial fibrillation. We updated the searches of CENTRAL in The Cochrane Library (2013, Issue 12 of 12), MEDLINE (to January 2014) and EMBASE (to January 2014). The reference lists of retrieved articles, recent reviews and meta-analyses were checked. Two independent authors selected randomised controlled trials comparing any antiarrhythmic drug with a control (no treatment, placebo, drugs for rate control) or with another antiarrhythmic drug in adults who had atrial fibrillation and in whom sinus rhythm was restored. Post-operative atrial fibrillation was excluded. Two authors independently assessed quality and extracted data. Studies were pooled, if appropriate, using Peto odds ratio (OR). All results were calculated at one year of follow-up. In this update three new studies, with 534 patients, were included making a total of 59 included studies comprising 21,305 patients. All included studies were randomised controlled trials. Allocation concealment was adequate in 17 trials, it was unclear in the remaining 42 trials. Risk of bias was assessed in all domains only in the trials included in this update.Compared with controls, class IA drugs quinidine and disopyramide (OR 2.39, 95% confidence interval (95% CI) 1.03 to 5.59, number needed to treat to harm (NNTH) 109, 95% CI 34 to 4985) and sotalol (OR 2.23, 95% CI 1.1 to 4.50, NNTH 169, 95% CI 60 to 2068) were associated with increased all-cause mortality. Other antiarrhythmics did not seem to modify mortality, but our data could be underpowered to detect mild increases in mortality for several of the drugs studied.Several class IA (disopyramide, quinidine), IC (flecainide, propafenone) and III (amiodarone, dofetilide, dronedarone, sotalol) drugs significantly reduced recurrence of atrial fibrillation (OR 0.19 to 0.70, number needed to treat to beneft (NNTB) 3 to 16). Beta-blockers (metoprolol) also significantly reduced atrial fibrillation recurrences (OR 0.62, 95% CI 0.44 to 0.88, NNTB 9).All analysed drugs increased withdrawals due to adverse affects and all but amiodarone, dronedarone and propafenone increased pro-arrhythmia. Only 11 trials reported data on stroke. None of them found any significant difference with the exception of a single trial than found less strokes in the group treated with dronedarone compared to placebo. This finding was not confirmed in others studies on dronedarone.We could not analyse heart failure and use of anticoagulation because few original studies reported on these measures. Several class IA, IC and III drugs, as well as class II drugs (beta-blockers), are moderately effective in maintaining sinus rhythm after conversion of atrial fibrillation. However, they increase adverse events, including pro-arrhythmia, and some of them (disopyramide, quinidine and sotalol) may increase mortality. Possible benefits on clinically relevant outcomes (stroke, embolism, heart failure) remain to be established.

Excessive Premature Atrial Complexes and the Risk of Recurrent Stroke or Death in an Ischemic Stroke Population.

PubMed

Vinther, Kristina H; Tveskov, Claus; Möller, Sören; Auscher, Soren; Osmanagic, Armin; Egstrup, Kenneth

2017-06-01

Our aim was to investigate the association of premature atrial complexes and the risk of recurrent stroke or death in patients with ischemic stroke in sinus rhythm. In a prospective cohort study, we used 24-hour Holter recordings to evaluate premature atrial complexes in patients consecutively admitted with ischemic strokes. Excessive premature atrial complexes were defined as >14 premature atrial complexes per hour and 3 or more runs of premature atrial complexes per 24 hours. During follow-up, 48-hour Holter recordings were performed after 6 and 12 months. Among patients in sinus rhythm, the association of excessive premature atrial complexes and the primary end point of recurrent stroke or death were estimated in both crude and adjusted Cox proportional hazards models. We further evaluated excessive premature atrial complexes contra atrial fibrillation in relation to the primary end point. Of the 256 patients included, 89 had atrial fibrillation. Of the patients in sinus rhythm (n = 167), 31 had excessive premature atrial complexes. During a median follow-up of 32 months, 50 patients (30% of patients in sinus rhythm) had recurrent strokes (n = 20) or died (n = 30). In both crude and adjusted models, excessive premature atrial complexes were associated with the primary end point, but not with newly diagnosed atrial fibrillation. Compared with patients in atrial fibrillation, those with excessive premature atrial complexes had similarly high risks of the primary end point. In patients with ischemic stroke and sinus rhythm, excessive premature atrial complexes were associated with a higher risk of recurrent stroke or death. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

[Left versus bi-atrial radiofrequency ablation in the treatment of atrial fibrillation].

PubMed

Wang, Jian-Gang; Meng, Xu; Li, Hui

2008-11-25

To evaluate the effectiveness of radiofrequency modified maze operation for the treatment of atrial fibrillation (AF) and compare the results of the left versus bi-atrial procedures. 305 patients of organic heart disease combined with AF, 117 males and 188 females, aged (53 +/- 10), that underwent cardiac valve operation (n = 293) and/or coronary artery bypass graft surgery (n = 14), received concomitant atrial fibrillation, bi-atrial (n = 160) or left atrial (n = 145) with a mean duration of (36 +/- 43) months. Follow-up was conducted for (28 +/- 5) (3 - 42) months. Thirteen patients (4.3%) died postoperatively: 7 died of multisystem and organ failure, 3 of low cardiac output, 1 of rupture of left ventricle, 1 of arrhythmia, and 1 of sudden death. During the follow-up, 1 patient died of heart failure, 1 of encephalorrhagia and 1 of unknown reason in the bi-atrial group. At the end of the procedure 223 patients (73.1%) had sinus rhythm, with a sinus rhythm rate of 66.9% (107/160) in the bi-atrial group, significant lower than that in the left atrial group (80.0%, 116/145, P < 0.05). At late follow-up, 215 of the 266 patients (80.8%) were in stable sinus rhythm. Sinus rhythm rate of the bi-atrial group was 80.0%, not significantly different from that of the left atrial group (81.9%, P > 0.05). The Kaplan-Meier survival analysis showed there was no significant difference in the AF rhythm rate between these 2 groups (P = 0.33). Logistic regression analysis showed that the left atrial diameter of >/= 80 mm was an independent predictor of AF recurrence. Both the left and bi-atrial procedures are successful in terms of restoring sinus rhythm. Left atrial ablation in severe cases and where the incision of right atrium is not needed is a reasonable choice.

Does preoperative atrial fibrillation influence early and late outcomes of coronary artery bypass grafting?

PubMed

Ngaage, Dumbor L; Schaff, Hartzell V; Mullany, Charles J; Sundt, Thoralf M; Dearani, Joseph A; Barnes, Sunni; Daly, Richard C; Orszulak, Thomas A

2007-01-01

The study objective was to describe the independent effect of preoperative atrial fibrillation on the outcome of coronary artery bypass grafting, including the causes of death (cardiac vs noncardiac). We analyzed the outcome of patients with preoperative atrial fibrillation who underwent on-pump coronary artery bypass grafting between 1993 and 2002 and compared them with matched controls in sinus rhythm; matching variables were age, gender, ejection fraction, and numbers of diseased coronary arteries and distal anastomoses. Direct patient follow-up focused on late complications and reinterventions, and we investigated causes for all deaths. Operative mortality (1.6% vs 1.9%, P = .79) was similar in patients with preoperative atrial fibrillation (n = 257) compared with patients in sinus rhythm (n = 269). The patients with atrial fibrillation had longer hospital stays (9 +/- 6 days vs 8 +/- 6 days, P = .0008) and a trend to more frequent early readmissions (13% vs 9%, P = .08). During follow-up (median 6.7 years, maximum 12 years), late hospital admission was more frequent in patients with atrial fibrillation (59% vs 31%, P < .0001). Risk of late mortality (all causes) in patients with atrial fibrillation was increased by 40% compared with patients in sinus rhythm (P = 0.02), and the late cardiac death rate in the atrial fibrillation group was 2.8 times that of the sinus rhythm group (P = .0004). Major adverse cardiac events occurred in 70% of patients with preoperative atrial fibrillation compared with 52% of patients in preoperative sinus rhythm (P < .0001). Subsequent rhythm-related intervention, including pacemaker implantations, was more common in the atrial fibrillation group (relative risk = 2.1, P = .0027). Uncorrected preoperative atrial fibrillation in patients undergoing coronary artery bypass grafting is associated with increased late cardiac morbidity and mortality and poor long-term survival. These data support consideration of atrial fibrillation surgery at the time of coronary artery bypass grafting.

Changes in Left Atrial Transport Function in Patients Who Maintained Sinus Rhythm After Successful Radiofrequency Catheter Ablation for Atrial Fibrillation: A 1-Year Follow-Up Multislice Computed Tomography Study.

PubMed

Kim, Jin-Seok; Im, Sung Il; Shin, Seung Yong; Kang, Jun Hyuk; Na, Jin Oh; Choi, Cheol Ung; Kim, Seong Hwan; Kim, Eung Ju; Rha, Seung-Woon; Park, Chang Gyu; Seo, Hong Seog; Oh, Dong Joo; Hwang, Chun; Kim, Young-Hoon; Yong, Hwan Seok; Lim, Hong Euy

2017-02-01

Functional remodeling of left atrium (LA) after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) has not been fully elucidated. This study aimed to determine the impact of RFCA on LA transport function in patients who maintained sinus rhythm (SR) after AF ablation. A total of 96 patients (paroxysmal AF [PAF] = 52) who maintained SR during 1 year after AF ablation were enrolled. Multislice computed tomography was performed to determine LA volume (LAV) and LA emptying fraction (LAEF) at pre-RFCA and 1-year post-RFCA. Creatine kinase-MB (CK-MB) and troponin-T levels were analyzed 1-day post-RFCA. At 1-year post-RFCA, mean LAV and LAEF decreased in overall patients. Based on LAEF change (ΔLAEF) cutoff of 5.0%, LAEF reduced in 41 patients (worsened group) and improved or showed no change in 55 patients (preserved group). Compared with preserved group, worsened group had a higher proportion of PAF, higher levels of CK-MB and troponin-T, and additional LA ablation. ΔLAEF was inversely correlated with CK-MB and troponin-T levels. Subgroup analysis showed that LAEF significantly decreased in PAF patients who underwent additional LA ablation. Multivariate analysis revealed that high baseline LAEF and additional LA ablation were independent predictors for worsened LAEF. Although SR was maintained for 1 year after AF ablation, LAEF as well as LAV decreased. The extent of LAEF deterioration was significantly associated with the amount of iatrogenic myocardial damage. Our data indicate that extensive atrial ablation may lead to LA functional deterioration, especially in patients with PAF. © 2016 Wiley Periodicals, Inc.

Surgery for atrial fibrillation.

PubMed

Viganò, M; Graffigna, A; Ressia, L; Minzioni, G; Pagani, F; Aiello, M; Gazzoli, F

1996-01-01

The mechanisms of atrial fibrillation arc multiple reentry circuits spinning around the atrial surface, and these baffle any attempt to direct surgical interruption. The purpose of this article is to report the surgical experience in the treatment of isolated and concomitant atrial fibrillation at the Cardiac Surgical Institute of the University of Pavia. In cases of atrial fibrillation secondary to mitral/valve disease, surgical isolation of the left atrium at the time of mitral valve surgery can prevent atrial fibrillation from involving the right atrium, which can exert its diastolic pump function on the right ventricle. Left atrial isolation was performed on 205 patients at the time of mitral valve surgery. Atrial partitioning ("maze operation") creates straight and blind atrial alleys so that non-recentry circuits can take place. Five patients underwent this procedure. In eight-cases of atrial fibrillation secondary to atrial septal defect, the adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation underwent surgical isolation of the right atrium associated which surgical correction of the defect, in order to let sinus rhythm govern the left atrium and the ventricles. "Lone" atrial fibrillation occurs in hearts with no detectable organic disease. Bi-atrial isolation with creation of an atrial septal internodal "corridor" was performed on 14 patients. In cases of atrial fibrillation secondary to mitral valve disease, left atrial isolation was performed on 205 patients at the time of mitral valve surgery with an overall sinus rhythm recovery of 44%. In the same period, sinus rhythm was recovered and persisted in only 19% of 252 patients who underwent mitral valve replacement along (P < 0.001). Sinus rhythm was less likely to recover in patients with right atriomegaly requiring tricuspid valve annuloplasty: 59% vs 84% (P < 0.001). Restoration of the right atrial function raised the cardiac index from 2.25 +/- 0.55 1/min per m2 during atrial fibrillation to 2.54 +/- 0.58 1/min per m2, with a mean percentage increase in cardiac index of 13.5% (P < 0.00018). Atrial partitioning ("maze operation") was performed on five patients with an immediate sinus rhythm recovery of 100%, but with two patients requiring pacemaker implant. Seven out of eight patients (87.5%), with atrial fibrillation secondary to atrial septal defect, who underwent surgical isolation of the right atrium at the time of surgery were free from atrial fibrillation and without medications. 2-52 months after operation. Thirteen of 14 patients with "lone" atrial fibrillation who underwent corridor procedure remained in sinus rhythm with a sinus rhythm recovery rate of 92%. Different surgical options can be chosen for different cases of atrial fibrillation, according to the underlying cardiac disease.

[Sinus rhythm: mechanisms and function].

PubMed

Lerebours, Guy

2007-01-01

The normal cardiac rhythm originates in a specialized region of the heart, the sinus node that is part of the nodal tissue. The rhythmic, impulse initiation of sinus node pacemaker cells results from a spontaneous diastolic depolarization that is initiated immediately after repolarization of the preceding actions potential. This slow diastolic depolarisation is typical of automatic cells and essential to their function. Several currents are involved in this diastolic depolarisation: a hyperpolarization activated inward current, termed "pacemaker" I(f) current, two Ca2+ currents (a L type and a T type), a delayed K+ current and a Na/Ca exchange current. The frequency of the automatic discharge is the main determinant of heart rate. However the sinus node activity is regulated by adrenergic and cholinergic neurotransmitters. Acetylcholine provokes the hyperpolarization of pacemaker cells and decreases the speed of the spontaneous diastolic depolarisation, thus slowing the sinus rate. Catecholamines lead to sinus tachycardia by increasing the diastolic depolarisation speed. In normal conditions, the observed resting heart rate is lower than the intrinsic frequency of the sinus node due to a "predominance" of the vagal tone. Neural regulation of the heart rate aims at meeting the metabolic needs of the tissues through a varying blood flow. Differences between diurnal and nocturnal mean heart rates are accounted for by neural influences. During the night, the increased vagal tone results in decreased heart rate. The exercise-induced tachycardia results from the sympathetic stimulation. It allows more blood to reach skeletal muscles, and as a consequence an increased supply of oxygen and nutrients. Compared to the variety of clinical arrhythmias, sinus rhythm is the basis for optimal exercise capacity and quality of life.

Validation of electromechanical wave imaging in a canine model during pacing and sinus rhythm.

PubMed

Grondin, Julien; Costet, Alexandre; Bunting, Ethan; Gambhir, Alok; Garan, Hasan; Wan, Elaine; Konofagou, Elisa E

2016-11-01

Accurate determination of regional areas of arrhythmic triggers is of key interest to diagnose arrhythmias and optimize their treatment. Electromechanical wave imaging (EWI) is an ultrasound technique that can image the transient deformation in the myocardium after electrical activation and therefore has the potential to detect and characterize location of triggers of arrhythmias. The objectives of this study were to investigate the relationship between the electromechanical and the electrical activation of the left ventricular (LV) endocardial surface during epicardial and endocardial pacing and during sinus rhythm as well as to map the distribution of electromechanical delays. In this study, 6 canines were investigated. Two external electrodes were sutured onto the epicardial surface of the LV. A 64-electrode basket catheter was inserted through the apex of the LV. Ultrasound channel data were acquired at 2000 frames/s during epicardial and endocardial pacing and during sinus rhythm. Electromechanical and electrical activation maps were synchronously obtained from the ultrasound data and the basket catheter, respectively. The mean correlation coefficient between electromechanical and electrical activation was 0.81 for epicardial anterior pacing, 0.79 for epicardial lateral pacing, 0.69 for endocardial pacing, and 0.56 for sinus rhythm. The electromechanical activation sequence determined by EWI follows the electrical activation sequence and more specifically in the case of pacing. This finding is of key interest in the role that EWI can play in the detection of the anatomical source of arrhythmias and the planning of pacing therapies such as cardiovascular resynchronization therapy. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

PULSESMART: Pulse-based Arrhythmia Discrimination Using a Novel Smartphone Application

PubMed Central

McManus, David D.; Chong, Jo Woon; Soni, Apurv; Saczynski, Jane S.; Esa, Nada; Napolitano, Craig; Darling, Chad E.; Boyer, Edward; Rosen, Rochelle K.; Floyd, Kevin C.; Chon, Ki H.

2015-01-01

Background Atrial fibrillation (AF) is a common and dangerous paroxysmal rhythm abnormality. Smartphones are increasingly used for mobile health applications by older patients at risk for AF and may be useful for AF screening. Objectives To test whether an enhanced smartphone app for AF detection can discriminate between sinus rhythm (SR), AF, premature atrial contractions (PACs) and premature ventricular contractions (PVCs). Methods We analyzed 219 2-minute pulse recordings from 121 participants with AF (n=98), PACs (n=15), or PVCs (n=15) using an iPhone 4S. We obtained pulsatile time series recordings in 91 participants after successful cardioversion to sinus rhythm from pre-existing AF. The PULSESMART app conducted pulse analysis using 3 methods [Root Mean Square of Successive RR Differences; Shannon Entropy; Poincare plot]. We examined the sensitivity, specificity, and predictive accuracy of the app for AF, PAC, and PVC discrimination from sinus rhythm using the 12-lead EKG or 3-lead telemetry as the gold standard. We also administered a brief usability questionnaire to a subgroup (n=65) of app users. Results The smartphone-based app demonstrated excellent sensitivity (0.970), specificity (0.935), and accuracy (0.951) for real-time identification of an irregular pulse during AF. The app also showed good accuracy for PAC (0.955) and PVC discrimination (0.960). The vast majority of surveyed app users (83%) reported that it was “useful” and “not complex” to use. Conclusions A smartphone app can accurately discriminate pulse recordings during AF from sinus rhythm, PACs, and PVCs. PMID:26391728

High intensity focused ultrasound ablation for atrial fibrillation: results from the National Spanish Registry.

PubMed

Reyes, Guillermo; Ruyra, Xavier; Valderrama, Francisco; Jimenez, Antonio; Duran, Dario; Perez, Enrique; Daroca, Tomas; Moya, Javier; Ramirez, Ulises; Aldamiz, Gonzalo

2016-10-01

A National Spanish Registry to compile all patients treated with high intensity focused ultrasound (HIFU) energy for atrial fibrillation (AF) was created to evaluate the safety and efficacy of AF surgical ablation. A national Spanish registry was created, and ten hospitals using HIFU to ablate AF joined it. A total of 412 patients undergoing cardiac surgery between 2006 and February 2013 were included. AF was divided between paroxysmal AF (33%) and persistent AF (67%) with a mean AF duration of 29.3±108.2 months. Mean left atrial diameter was 51.2±6.5 mm. Mean underlying heart disease were aortic valve disease (49.3%), ischemic disease (25.2%) and mitral disease (33.2%) Clinical follow-up of patients and a 6 months postoperative echocardiogram were performed in all patients. A pacemaker implantation was needed in 4.9% of patients with a perioperative stroke in 2.5%. Rhythm at discharge from hospital was sinus rhythm in 58%, AF in 35.9% and atrial flutter in 0.8% of patients. Sinus rhythm restoration at 6, 12, 24 and 36 months follow-up was achieved in 66.1%, 63.8%, 63.9% and 45.9% of patients respectively. Multivariate analysis showed paroxysmal AF and sinus rhythm restoration in the operating theatre as factors related to sinus rhythm long term restoration. The Spanish national registry showed an efficacy of AF ablation with the HIFU Epicor system of 66.1%, 63.8%, 63.9% and 45.9% at 6, 12, 24 and 36 months follow-up. There were no device-related complications.

Routine versus aggressive upstream rhythm control for prevention of early atrial fibrillation in heart failure: background, aims and design of the RACE 3 study.

PubMed

Alings, M; Smit, M D; Moes, M L; Crijns, H J G M; Tijssen, J G P; Brügemann, J; Hillege, H L; Lane, D A; Lip, G Y H; Smeets, J R L M; Tieleman, R G; Tukkie, R; Willems, F F; Vermond, R A; Van Veldhuisen, D J; Van Gelder, I C

2013-07-01

Rhythm control for atrial fibrillation (AF) is cumbersome because of its progressive nature caused by structural remodelling. Upstream therapy refers to therapeutic interventions aiming to modify the atrial substrate, leading to prevention of AF. The Routine versus Aggressive upstream rhythm Control for prevention of Early AF in heart failure (RACE 3) study hypothesises that aggressive upstream rhythm control increases persistence of sinus rhythm compared with conventional rhythm control in patients with early AF and mild-to-moderate early systolic or diastolic heart failure undergoing electrical cardioversion. RACE 3 is a prospective, randomised, open, multinational, multicenter trial. Upstream rhythm control consists of angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers, mineralocorticoid receptor antagonists, statins, cardiac rehabilitation therapy, and intensive counselling on dietary restrictions, exercise maintenance, and drug adherence. Conventional rhythm control consists of routine rhythm control therapy without cardiac rehabilitation therapy and intensive counselling. In both arms, every effort is made to keep patients in the rhythm control strategy, and ion channel antiarrhythmic drugs or pulmonary vein ablation may be instituted if AF relapses. Total inclusion will be 250 patients. If upstream therapy proves to be effective in improving maintenance of sinus rhythm, it could become a new approach to rhythm control supporting conventional pharmacological and non-pharmacological rhythm control.

Efficacy of β blockers in patients with heart failure plus atrial fibrillation: an individual-patient data meta-analysis.

PubMed

Kotecha, Dipak; Holmes, Jane; Krum, Henry; Altman, Douglas G; Manzano, Luis; Cleland, John G F; Lip, Gregory Y H; Coats, Andrew J S; Andersson, Bert; Kirchhof, Paulus; von Lueder, Thomas G; Wedel, Hans; Rosano, Giuseppe; Shibata, Marcelo C; Rigby, Alan; Flather, Marcus D

2014-12-20

Atrial fibrillation and heart failure often coexist, causing substantial cardiovascular morbidity and mortality. β blockers are indicated in patients with symptomatic heart failure with reduced ejection fraction; however, the efficacy of these drugs in patients with concomitant atrial fibrillation is uncertain. We therefore meta-analysed individual-patient data to assess the efficacy of β blockers in patients with heart failure and sinus rhythm compared with atrial fibrillation. We extracted individual-patient data from ten randomised controlled trials of the comparison of β blockers versus placebo in heart failure. The presence of sinus rhythm or atrial fibrillation was ascertained from the baseline electrocardiograph. The primary outcome was all-cause mortality. Analysis was by intention to treat. Outcome data were meta-analysed with an adjusted Cox proportional hazards regression. The study is registered with Clinicaltrials.gov, number NCT0083244, and PROSPERO, number CRD42014010012. 18,254 patients were assessed, and of these 13,946 (76%) had sinus rhythm and 3066 (17%) had atrial fibrillation at baseline. Crude death rates over a mean follow-up of 1·5 years (SD 1·1) were 16% (2237 of 13,945) in patients with sinus rhythm and 21% (633 of 3064) in patients with atrial fibrillation. β-blocker therapy led to a significant reduction in all-cause mortality in patients with sinus rhythm (hazard ratio 0·73, 0·67-0·80; p<0·001), but not in patients with atrial fibrillation (0·97, 0·83-1·14; p=0·73), with a significant p value for interaction of baseline rhythm (p=0·002). The lack of efficacy for the primary outcome was noted in all subgroups of atrial fibrillation, including age, sex, left ventricular ejection fraction, New York Heart Association class, heart rate, and baseline medical therapy. Based on our findings, β blockers should not be used preferentially over other rate-control medications and not regarded as standard therapy to improve prognosis in patients with concomitant heart failure and atrial fibrillation. Menarini Farmaceutica Internazionale (administrative support grant). Copyright © 2014 Elsevier Ltd. All rights reserved.

Sustained Accelerated Idioventricular Rhythm in a Centrifuge-Simulated Suborbital Spaceflight.

PubMed

Suresh, Rahul; Blue, Rebecca S; Mathers, Charles; Castleberry, Tarah L; Vanderploeg, James M

2017-08-01

Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular contractions, and even atrial fibrillations or flutter patterns. However, events are generally short-lived and resolve rapidly after cessation of acceleration. This case report describes a prolonged ectopic ventricular rhythm in response to high G exposure. A previously healthy 30-yr-old man voluntarily participated in centrifuge trials as a part of a larger study, experiencing a total of 7 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak +3.5 Gz, run 2) and two +Gx runs (peak +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz). Hemodynamic data collected included blood pressure, heart rate, and continuous three-lead electrocardiogram. Following the final acceleration exposure of the last Day 2 run (peak +4.5 Gx and +4.0 Gz combined, resultant +6.0 G), during a period of idle resting centrifuge activity (resultant vector +1.4 G), the subject demonstrated a marked change in his three-lead electrocardiogram from normal sinus rhythm to a wide-complex ectopic ventricular rhythm at a rate of 91-95 bpm, consistent with an accelerated idioventricular rhythm (AIVR). This rhythm was sustained for 2 m, 24 s before reversion to normal sinus. The subject reported no adverse symptoms during this time. While prolonged, the dysrhythmia was asymptomatic and self-limited. AIVR is likely a physiological response to acceleration and can be managed conservatively. Vigilance is needed to ensure that AIVR is correctly distinguished from other, malignant rhythms to avoid inappropriate treatment and negative operational impacts.Suresh R, Blue RS, Mathers C, Castleberry TL, Vanderploeg JM. Sustained accelerated idioventricular rhythm in a centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(8):789-793.

Evaluation of a New Cardiac Pacemaker

ClinicalTrials.gov

2013-06-25

Atrial Fibrillation With 2 or 3° AV or Bifascicular Bundle Branch (BBB) Block; Normal Sinus Rhythm With 2 or 3° AV or BBB Block; Sinus Bradycardia With Infrequent Pauses or Unexplained Syncope With EP Findings

Instantaneous electrocardiographic changes and transient sinus rhythm restoration in severe hyperkalaemia.

PubMed

Gogas, Bill D; Iliodromitis, Efstathios K; Leftheriotis, Dionyssios I; Flevari, Panagiota G; Rallidis, Loukianos S; Kremastinos, Dimitrios T

2011-04-14

Severe hyperkalaemia is a life threatening electrolyte abnormality that if not treated urgently, might cause electric death. Hyperkalaemia induced electrocardiogram (ECG) alterations vary according to the levels and rate of increase of potassium concentration ([K(+)]) in the extracellular milieu but the paradox is that not all these cases provide ECG changes. We describe the first case in the literature of transient sinus rhythm (SR) recovery despite severe hyperkalaemia in a 57-year-old (yo) male patient with impressive ECG changes considering the heart rhythm and QRS morphology. We also review the literature for the mechanism of ECG alterations induced by hyperkalaemia. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Electrophysiologic effects of a novel selective adenosine A1 agonist (CVT-510) on atrioventricular nodal conduction in humans.

PubMed

Lerman, B B; Ellenbogen, K A; Kadish, A; Platia, E; Stein, K M; Markowitz, S M; Mittal, S; Slotwiner, D J; Scheiner, M; Iwai, S; Belardinelli, L; Jerling, M; Shreeniwas, R; Wolff, A A

2001-07-01

CVT-510, N-(3(R)-tetrahydrofuranyl)-6-aminopurine riboside, is a selective A(1)-adenosine receptor agonist with potential potent antiarrhythmic effects in tachycardias involving the atrioventricular (AV) node. This study, the first in humans, was designed to determine the effects of CVT-510 on AV nodal conduction and hemodynamics. Patients in sinus rhythm with normal AV nodal function at electrophysiologic study (n = 32) received a single intravenous bolus of CVT-510. AH and HV intervals were measured during sinus rhythm and during atrial pacing at 1, 5, 10, 15, 20, 30, 45, and 60 minutes after the bolus. Increasing doses of CVT-510 (0.3 to 10 microg/kg) caused a dose-dependent increase in the AH interval. At 1 minute, a dose of 10 microg/kg increased the AH interval during sinus rhythm from 93 +/- 23 msec to 114 +/- 37 msec, p = 0.01 and from 114 +/- 31 msec to 146 +/- 44 msec during atrial pacing at 600 msec, p = 0.003). The AH interval returned to baseline by 20 minutes. CVT-510 at doses of 0.3 to 10 microg/kg had no effect on sinus rate, HV interval, or systemic blood pressure, and was not associated with serious adverse effects. At doses of 15 and 30 microg/kg, CVT-510 produced transient second/third degree AV heart block in all four patients treated. One of these patients also had a prolonged sedative effect that was reversed with aminophylline. CVT-510 promptly prolongs AV nodal conduction and does not affect sinus rate or blood pressure. Selective stimulation of the A(1)-adenosine receptor by CVT-510 may be useful for immediate control of heart rate in atrial fibrillation/flutter and to convert paroxysmal supraventricular tachycardia to sinus rhythm, while avoiding vasodilatation mediated by the A(2)-adenosine receptor, as well as the vasodepressor and negative inotropic effects associated with beta-adrenergic receptor blockade and/or calcium channel blockers.

Bidirectional Cardio-Respiratory Interactions in Heart Failure.

PubMed

Radovanović, Nikola N; Pavlović, Siniša U; Milašinović, Goran; Kirćanski, Bratislav; Platiša, Mirjana M

2018-01-01

We investigated cardio-respiratory coupling in patients with heart failure by quantification of bidirectional interactions between cardiac (RR intervals) and respiratory signals with complementary measures of time series analysis. Heart failure patients were divided into three groups of twenty, age and gender matched, subjects: with sinus rhythm (HF-Sin), with sinus rhythm and ventricular extrasystoles (HF-VES), and with permanent atrial fibrillation (HF-AF). We included patients with indication for implantation of implantable cardioverter defibrillator or cardiac resynchronization therapy device. ECG and respiratory signals were simultaneously acquired during 20 min in supine position at spontaneous breathing frequency in 20 healthy control subjects and in patients before device implantation. We used coherence, Granger causality and cross-sample entropy analysis as complementary measures of bidirectional interactions between RR intervals and respiratory rhythm. In heart failure patients with arrhythmias (HF-VES and HF-AF) there is no coherence between signals ( p < 0.01), while in HF-Sin it is reduced ( p < 0.05), compared with control subjects. In all heart failure groups causality between signals is diminished, but with significantly stronger causality of RR signal in respiratory signal in HF-VES. Cross-sample entropy analysis revealed the strongest synchrony between respiratory and RR signal in HF-VES group. Beside respiratory sinus arrhythmia there is another type of cardio-respiratory interaction based on the synchrony between cardiac and respiratory rhythm. Both of them are altered in heart failure patients. Respiratory sinus arrhythmia is reduced in HF-Sin patients and vanished in heart failure patients with arrhythmias. Contrary, in HF-Sin and HF-VES groups, synchrony increased, probably as consequence of some dominant neural compensatory mechanisms. The coupling of cardiac and respiratory rhythm in heart failure patients varies depending on the presence of atrial/ventricular arrhythmias and it could be revealed by complementary methods of time series analysis.

The management of ventricular dysrhythmia in aconite poisoning.

PubMed

Coulson, James M; Caparrotta, Thomas M; Thompson, John P

2017-06-01

Aconite poisoning is relatively rare but is frequently complicated by ventricular dysrhythmias, which may be fatal. Molecular basis of aconite alkaloid ventricular arrhythmogenicity: Aconite exerts its toxic effects due to the presence of an admixture of alkaloids present in all parts of the plant. The major target of these aconite alkaloids is the fast voltage-gates sodium channel, where they cause persistent activation. This blockade of the channel in the activated state promotes automaticity within the ventricular myocardium and the generation of ventricular arrhythmias. Aconitine-induced arrhythmias: Aconite alkaloids are known to cause many different types of disturbance of heart rhythm. However, this focused review specifically looks at ventricular rhythm disturbances, namely ventricular ectopy, ventricular tachycardia, torsades des pointes and ventricular fibrillation. The objective of this review was to identify the outcome of anti-dysrhythmic strategies from animal studies and case reports in humans in order to guide the management of ventricular dysrhythmias in aconite poisoning in humans. A review of the literature in English was conducted in PubMed and Google Scholar from 1966 to July 2016 using the search terms "aconite/aconitine"; "aconite/aconitine + poisoning" and "aconite/aconitine + dysrhythmia". 168 human case-reports and case-series were identified by these searches, of which 103 were rejected if exposure to aconite did not result in ventricular dysrhythmias, if it was uncertain as to whether aconite had been ingested, if other agents were co-ingested, if there was insufficient information to determine the type of treatments administered or if there was insufficient information to determine outcome. Thus, 65 case reports of probable aconite poisoning that resulted in ventricular dysrhythmias were identified. Toxicokinetic data in aconite poisoning: Data were only available in three papers; the presence of ventricular rhythm disturbances directly correlated with the concentration of aconite alkaloids in the plasma. 54 of 65 cases developed ventricular tachycardia, six developed torsades des pointes, 15 patients developed ventricular fibrillation, 10 developed ventricular ectopics and one developed a broad complex tachycardia not otherwise specified; each dysrhythmia was regarded as separate and patients may have had more than one dysrhythmia. 10 patients died, giving a mortality of 15%. In total, 147 treatments were administered to 65 patients. 46 of the interventions were assessed by the authors as having been associated with successful restoration of sinus rhythm. Flecainide administration was accompanied by dysrhythmia termination in six of seven cases. Mexiletine was connected with correcting dysrhythmias in 3 of 3 cases. Procainamide administration was associated with return to sinus rhythm in 2 of 2 cases. Prolonged cardio-pulmonary resuscitation was administered to 15 patients where it was associated with a return to sinus rhythm in nine of these. Amiodarone was linked to success in correcting dysrhythmias in 11 of 20 cases. Cardiopulmonary bypass use was associated with a return to sinus rhythm in four out of six cases. Epinephrine was documented as being employed on four occasions, and was associated with a restoration of sinus rhythm on two of these. Magnesium sulphate administration was accompanied by dysrhythmia termination in two of nine cases. Direct cardioversion was associated with a return of sinus rhythm in 5 of 30 cases. However, it is not certain whether the drug treatment influenced the course of the dysrhythmia. Based on the evidence available from human case reports, flecainaide or amiodarone appear to be more associated with a return to sinus rhythm than lidocaine and/or cardioversion, although it is not established whether the administration of treatment caused reversion to normal sinus rhythm. The potential beneficial effects of amiodarone were not observed in animal studies. This may be due to intra-species differences between ion channels or relate to the wider cardiovascular toxicity of aconite that extends beyond arrhythmias. Prolonged cardiopulmonary resuscitation and cardiopulmonary bypass should be considered as an integral part of good clinical care as "time-buying" strategies to allow the body to excrete the toxic alkaloids. There may also be a role for mexiletine, procainamide and magnesium sulphate.

Low-energy cardioversion of spontaneous atrial fibrillation. Immediate and long-term results.

PubMed

Lévy, S; Ricard, P; Gueunoun, M; Yapo, F; Trigano, J; Mansouri, C; Paganelli, F

1997-07-01

Recent studies have suggested that induced atrial fibrillation (AF) could be successfully terminated by using a two-catheter electrode system and low energy (< 400 V). This study evaluated the efficacy and safety of low-energy cardioversion in spontaneous chronic and paroxysmal AF. Forty-two consecutive patients with spontaneous AF underwent low-energy electrical cardioversion. AF was chronic (> or = 1 month) with a mean duration of 9 +/- 19 months in 28 patients (group I) or paroxysmal with a history of recurrent attacks and a mean duration of the present episode of 7 +/- 16 days in 14 patients (group II). An underlying heart disease was present in 28 patients. A 3/3-ms biphasic shock was delivered between catheters positioned in the right atrium and the coronary sinus in 32 patients. In 10 patients, the left pulmonary artery branch was used. The catheters were connected to a custom external defibrillator. The shocks were synchronized to the R wave. Following a test shock of 60 V, the energy was increased in 40-V steps until a maximum of 400 V or restoration of sinus rhythm. Sinus rhythm was restored in 22 of the 28 patients (78%) of group I by using a mean leading-edge voltage of 297 +/- 57 V (mean energy 3.3 +/- 1.3 J) and in 11 of 14 patients (78%) of group II by using a mean leading-edge voltage of 223 +/- 41 V (mean energy, 1.8 +/- 0.7 J). The energy required for terminating chronic AF was significantly (P < .001) higher than that required for terminating paroxysmal AF. Among the other variables studied, the duration of AF significantly affected the successful voltage. Ventricular proarrhythmia occurred in 1 patient with atrial flutter due to an unsynchronized shock. Of the 22 patients of group I in whom sinus rhythm was restored, 14 (63%) remained in sinus rhythm with a mean follow-up of 9 +/- 3 months. Pain level showed a good correlation with increasing voltage. However, a marked inter-individual variation was noted. Atrial defibrillation using low energy between two intracardiac catheters with an electrical field between the right and left atria and the protocol used is feasible in patients with persistent spontaneous AF. The technique is safe provided synchronization to the R wave is achieved. A low recurrence rate of AF was seen in patients in whom sinus rhythm was restored.

Impact of preoperative atrial fibrillation on mortality and cardiovascular outcomes of mechanical mitral valve replacement for rheumatic mitral valve disease.

PubMed

Wang, Bin; Xu, Zhi-yun; Han, Lin; Zhang, Guan-xin; Lu, Fang-lin; Song, Zhi-gang

2013-03-01

The prognostic significance of preoperative atrial fibrillation on mitral valve replacement remains unclear. The aim of this study was to explore the effects of the presence of preoperative atrial fibrillation on mortality and cardiovascular outcomes of mitral valve replacement for rheumatic valve disease. A retrospective analysis was performed on a total of 793 patients who underwent mitral valve replacement with or without tricuspid valve repair in our hospital. The patients selected were divided into two groups according to preoperative rhythm status. Patients with preoperative atrial fibrillation were assigned to the AF group, while patients in preoperative sinus rhythm were assigned to the SR group. Postoperative follow-up was performed by outpatient visits, as well as by telephone and written correspondence. Data gathered included survivorship, postoperative complications, left ventricular function and tricuspid regurgitation. For patients with atrial fibrillation vs those in sinus rhythm, there was no difference in postoperative mortality and morbidity. Follow-up was a mean of 8.6 ± 2.4 years. For patients with preoperative atrial fibrillation, 10-year survival from a Kaplan-Meier curve was 88.7%, compared with 96.6% in patients with preoperative sinus rhythm (P = 0.002). Multivariate analysis identified low left ventricular ejection fraction, older age, large left atrium and preoperative atrial fibrillation as significant adverse predictors for overall survival. Freedom from thromboembolism complications at 13 years was lower for patients with preoperative atrial fibrillation without maze procedure and left atrial appendage ligation, compared with that for patients with preoperative sinus rhythm without maze procedure and left atrial appendage ligation, and patients with concomitant maze procedure and left atrial appendage ligation (76.3 vs 94.8 vs 94.0%, respectively; P = 0.001). On echocardiography, the proportion of patients with significant tricuspid regurgitation was 38.7% (atrial fibrillation patients) vs 25.4% (patients in sinus rhythm; P < 0.001). Left ventricular ejection fraction measured 5 years after surgery increased by an average of 1.2% in the AF group, while it increased by 5.3% in the SR group (P = 0.028). Preoperative atrial fibrillation is a risk factor for long-term mortality, thromboembolism complications and tricuspid regurgitation, and it also has an adverse effect on the degree of improvement when considering left ventricular function.

[Changes of heart electrophysiological parameters after destruction of epicardial subplexuses that innervate sinoatrial node].

PubMed

Kulboka, Arūnas; Veikutis, Vincentas; Pauza, Dainius Haroldas; Lekas, Raimundas

2003-01-01

The aims of present study were to verify the topography of the intracardiac nerve subplexuses (INS) by using electrophysiological methods, its relations with sinoatrial (SA) node function and to investigate possibility of selective surgical SA node denervation. Fifteen mongrel dogs of either sex weighing 8 to 15 kg were used for electrophysiological studies. Both cervical vagosympathetic trunks were isolated and crushed by tight ligatures. Nervus subplexuses destructions were performed by cryocoagulation in three zones located around the right superior vena cava: ventral, lateral and dorsal. The sinus rhythm, SA node function recovery time, AV node conductivity, AV node and atrial effective refractory period were measured. Five experiments in each of three zones were performed. Experimental data show that destruction of the epicardial nerves has different effect on electrophysiological parameters. After destruction of the anterior zone of the right atrium the sinus rhythm decreased on an average by 11.6%; SA node function recovery time prolonged by 7.2%; AV node conductivity decreased by 13.1%; AV node effective refractory period prolonged by 12.9% and atrial effective refractory period, by 10.9 %. Measurements of electrophysiological parameters after intravenous injection of atropine sulphate show that sinus rhythm decreased on an average by 23.4%; SA node function recovery time increased by 9.1%; the conductivity of AV node decreased by 10.2%; AV node effective refractory period prolonged by 15.4% and atrial effective refractory period, by 13.2%. After destruction of the intracardiac nerves of the lateral zone, the sinus rhythm decreased by 15.7%; SA node function recovery time increased by 16.3%; AV node conductivity decreased by 8.3%; AV node effective refractory period and atrial effective refractory period prolonged by 11.9% and 10.0%, respectively. After the atropine sulphate intravenous injection, the sinus rhythm decreased on an average by 7.1%, SA node function recovery time prolonged by 7.1%, AV conductivity decreased by 9.1%, AV node effective refractory period increased by 12.4%, and atrial effective refractory period prolonged by 12.5%. After destruction of the nerves in the dorsal zone the changes of electrophysiological parameters were opposite to those obtained after destruction of the nerve tracts in the anterior or lateral zones: the sinus rhythm increased on an average by 4.3%; SA node function recovery time shortened by 8.8%; AV conductivity increased by 9.7%; AV node and atrial effective refractory period decreased by 12.3% and 12.1%, respectively. After intravenous atropine sulphate infusion, sinus rhythm decreased on an average by 8.3%; SA node function recovery time prolonged by 9.6%; AV node conductivity decreased by 5%; AV node and atrial effective refractory period prolonged by 4.2% and 5.2%, respectively. The average changes of electrophysiological parameters before and after INS destruction shows that cryocoagulation of ventral and lateral zones eliminates the effects of sympathetic tone to SA and AV nodal activity. Cryocoagulation of dorsal zone eliminates the effects of nervus vagus to both nodal structures. These findings shows the possibility alter or correct SA node function by making selective surgical SA node denervation.

Validation of Electromechanical Wave Imaging in a canine model during pacing and sinus rhythm

PubMed Central

Grondin, Julien; Costet, Alexandre; Bunting, Ethan; Gambhir, Alok; Garan, Hasan; Wan, Elaine; Konofagou, Elisa E.

2016-01-01

Background Accurate determination of regional areas of arrhythmic triggers is of key interest to diagnose arrhythmias and optimize their treatment. Electromechanical wave imaging (EWI) is an ultrasound technique that can image the transient deformation in the myocardium following electrical activation and therefore has the potential to detect and characterize location of triggers of arrhythmias. Objectives The objectives of this study are to investigate the relationship between electromechanical and electrical activation of the left-ventricular (LV) endocardial surface during epicardial and endocardial pacing as well as during sinus rhythm and also to investigate the distribution of electromechanical delays. Methods In this study, six canines were investigated. Two external electrodes were sutured onto the epicardial surface of the left ventricle (LV). A 64-electrode basket catheter was inserted through the apex of the LV. Ultrasound channel data were acquired at 2000 frames/s during epicardial and endocardial pacing as well as during sinus rhythm. Electromechanical and electrical activation maps were synchronously obtained from the ultrasound data and the basket catheter respectively. Results The mean correlation coefficient between electromechanical and electrical activation was R=0.81 for epicardial anterior pacing, R=0.79 for epicardial lateral pacing, R=0.69 for endocardial pacing and R=0.56 for sinus rhythm. Conclusions The electromechanical activation sequence determined by EWI follows the electrical activation sequence and more specifically in the case of pacing. This finding is of key interest in the role that EWI can play in the detection of the anatomical source of arrhythmias and the planning of pacing therapies such as cardiovascular resynchronization therapy. PMID:27498277

A novel approach to restore atrial function after the maze procedure in patients with an enlarged left atrium.

PubMed

Marui, Akira; Tambara, Keiichi; Tadamura, Eiji; Saji, Yoshiaki; Sasahashi, Nozomu; Ikeda, Tadashi; Nishina, Takeshi; Komeda, Masashi

2007-08-01

Left atrial (LA) volume reduction surgery concomitant with the maze procedure has been reported to facilitate sinus rhythm recovery even in patients with refractory atrial fibrillation (AF) with an enlarged LA. However, it is unknown whether the procedures can also restore effective atrial function of the enlarged LA with over-stretched myocardium. The maze procedures in association with mitral valve surgery were performed to 57 AF patients with an enlarged LA (LA diameter >or=60mm). Among them, 32 patients had concomitant LA volume reduction surgery (VR group). Another 25 patients did not have the volume reduction (control group). Three months postoperatively LA end-diastolic volume (LAEDV, ml) assessed by magnetic resonance (MR) imaging was larger in the VR group than that in the control group (291+/-117 vs 223+/-81 ml, p<0.05). Postoperatively, sinus rhythm recovery rate was better (84 vs 68%, p<0.05) and LAEDV was drastically smaller (118+/-48 vs 203+/-76 ml, p<0.001) in the VR group than those in the control group. Among the patients with sinus rhythm recovery in both groups, LA contraction ejection fraction (%) improved in the VR group but not in the control group (22.3+/-7.8 vs 10.3+/-4.7%, p<0.001). The LA volume reduction surgery concomitant with the maze procedure restored contraction of the enlarged LA; however, the maze procedure alone did not restore LA contraction in spite of successful sinus rhythm recovery. LA volume reduction surgery may be desirable to the patients with refractory AF with over-stretched LA.

Bachmann's Bundle Pacing not Only Improves Interatrial Conduction but Also Reduces the Need for Ventricular Pacing.

PubMed

Sławuta, Agnieszka; Kliś, Magdalena; Skoczyński, Przemysław; Bańkowski, Tomasz; Moszczyńska-Stulin, Joanna; Gajek, Jacek

2016-01-01

Patients treated for sick sinus syndrome may have interatrial conduction disorder leading to atrial fibrillation. This study was aimed to assess the influence of the atrial pacing site on interatrial and atrioventricular conduction as well as the percentage of ventricular pacing in patients with sick sinus syndrome implanted with atrioventricular pacemaker. The study population: 96 patients (58 females, 38 males) aged 74.1 ± 11.8 years were divided in two groups: Group 1 (n = 44) with right atrial appendage pacing and group 2 (n = 52) with Bachmann's area pacing. We assessed the differences in atrioventricular conduction in sinus rhythm and atrial 60 and 90 bpm pacing, P-wave duration and percentage of ventricular pacing. No differences in baseline P-wave duration in sinus rhythm between the groups (102.4 ± 17 ms vs. 104.1 ± 26 ms, p = ns.) were noted. Atrial pacing 60 bpm resulted in longer P-wave in group 1 vs. group 2 (138.3 ± 21 vs. 106.1 ± 15 ms, p < 0.01). The differences between atrioventricular conduction time during sinus rhythm and atrial pacing at 60 and 90 bpm were significantly longer in patients with right atrial appendage vs. Bachmann's pacing (44.1 ± 17 vs. 9.2 ± 7 ms p < 0.01 and 69.2 ± 31 vs. 21.4 ± 12 ms p < 0.05, respectively). The percentage of ventricular pacing was higher in group 1 (21 vs. 4%, p < 0.01). Bachmann's bundle pacing decreases interatrial and atrioventricular conduction delay. Moreover, the frequency-dependent atrioventricular conduction lengthening is much less pronounced during Bachmann's bundle pacing. Right atrial appendage pacing in sick sinus syndrome patients promotes a higher percentage of ventricular pacing.

Is AF Ablation Cost Effective?

PubMed Central

Martin-Doyle, William; Reynolds, Matthew R.

2010-01-01

The use of catheter ablation to treat AF is increasing rapidly, but there is presently an incomplete understanding of its cost-effectiveness. AF ablation procedures involve significant up-front expenditures, but multiple randomized trials have demonstrated that ablation is more effective than antiarrhythmic drugs at maintaining sinus rhythm in a second-line and possibly first-line rhythm control setting. Although truly long-term data are limited, ablation, as compared with antiarrrhythmic drugs, also appears associated with improved symptoms and quality of life and a reduction in downstream hospitalization and other health care resource utilization. Several groups have developed cost effectiveness models comparing AF ablation primarily to antiarrhythmic drugs and the model results suggest that ablation likely falls within the range generally accepted as cost-effective in developed nations. This paper will review available information on the cost-effectiveness of catheter ablation for the treatment of atrial fibrillation, and discuss continued areas of uncertainty where further research is required. PMID:20936083

Mitochondrial apoptotic pathway activation in the atria of heart failure patients due to mitral and tricuspid regurgitation.

PubMed

Chang, Jen-Ping; Chen, Mien-Cheng; Liu, Wen-Hao; Lin, Yu-Sheng; Huang, Yao-Kuang; Pan, Kuo-Li; Ho, Wan-Chun; Fang, Chih-Yuan; Chen, Chien-Jen; Chen, Huang-Chung

2015-08-01

Apoptosis occurs in atrial cardiomyocytes in mitral and tricuspid valve disease. The purpose of this study was to examine the respective roles of the mitochondrial and tumor necrosis factor-α receptor associated death domain (TRADD)-mediated death receptor pathways for apoptosis in the atrial cardiomyocytes of heart failure patients due to severe mitral and moderate-to-severe tricuspid regurgitation. This study comprised eighteen patients (7 patients with persistent atrial fibrillation and 11 in sinus rhythm). Atrial appendage tissues were obtained during surgery. Three purchased normal human left atrial tissues served as normal controls. Moderately-to-severely myolytic cardiomyocytes comprised 59.7±22.1% of the cardiomyocytes in the right atria and 52.4±12.9% of the cardiomyocytes in the left atria of mitral and tricuspid regurgitation patients with atrial fibrillation group and comprised 58.4±24.8% of the cardiomyocytes in the right atria of mitral and tricuspid regurgitation patients with sinus rhythm. In contrast, no myolysis was observed in the normal human adult left atrial tissue samples. Immunohistochemical analysis showed expression of cleaved caspase-9, an effector of the mitochondrial pathways, in the majority of right atrial cardiomyocytes (87.3±10.0%) of mitral and tricuspid regurgitation patients with sinus rhythm, and right atrial cardiomyocytes (90.6±31.4%) and left atrial cardiomyocytes (70.7±22.0%) of mitral and tricuspid regurgitation patients with atrial fibrillation. In contrast, only 5.7% of cardiomyocytes of the normal left atrial tissues showed strongly positive expression of cleaved caspase-9. Of note, none of the atrial cardiomyocytes in right atrial tissue in sinus rhythm and in the fibrillating right and left atria of mitral and tricuspid regurgitation patients, and in the normal human adult left atrial tissue samples showed cleaved caspase-8 expression, which is a downstream effector of TRADD of the death receptor pathway. Immunoblotting of atrial extracts showed that there was enhanced expression of cytosolic cytochrome c, an effector of the mitochondrial pathways, but no expression of membrane TRADD and cytosolic caspase-8 in the right atrial tissue of mitral and tricuspid regurgitation patients with sinus rhythm, and right atrial and left atrial tissues of mitral and tricuspid regurgitation patients with atrial fibrillation. Taken together, this study showed that mitochondrial pathway for apoptosis was activated in the right atria in sinus rhythm and in the left and right atria in atrial fibrillation of heart failure patients due to mitral and tricuspid regurgitation, and this mitochondrial pathway activation may contribute to atrial contractile dysfunction and enlargement in this clinical setting. Copyright © 2015. Published by Elsevier Inc.

Effectiveness of direct-current cardioversion for treatment of supraventricular tachyarrhythmias, in particular atrial fibrillation, in surgical intensive care patients.

PubMed

Mayr, Andreas; Ritsch, Nicole; Knotzer, Hans; Dünser, Martin; Schobersberger, Wolfgang; Ulmer, Hanno; Mutz, Norbert; Hasibeder, Walter

2003-02-01

To evaluate primary success rate and effectiveness of direct-current cardioversion in postoperative critically ill patients with new-onset supraventricular tachyarrhythmias. Prospective intervention study. Twelve-bed surgical intensive care unit in a university teaching hospital. Thirty-seven consecutive, adult surgical intensive care unit patients with new-onset supraventricular tachyarrhythmias without previous history of tachyarrhythmias. Direct-current cardioversion using a monophasic, damped sinus-wave defibrillator. Energy levels used were 50, 100, 200, and 300 J for regular supraventricular tachyarrhythmias (n = 6) and 100, 200, and 360 J for irregular supraventricular tachyarrhythmias (n = 31). None of the patients was hypoxic, hypokalemic, or hypomagnesemic at onset of supraventricular tachyarrhythmia. Direct-current cardioversion restored sinus rhythm in 13 of 37 patients (35% primary responders). Most patients responded to the first or second direct-current cardioversion shock. Only one of 25 patients requiring more than two direct-current cardioversion shocks converted into sinus rhythm. Primary responders were significantly younger and demonstrated significant differences in arterial Po2 values at onset of supraventricular tachyarrhythmias compared with nonresponders. At 24 and 48 hrs, only six (16%) and five (13.5%) patients remained in sinus rhythm, respectively. In contrast to recent literature, direct-current cardioversion proved to be an ineffective method for treatment of new-onset supraventricular tachyarrhythmias and, in particular, atrial fibrillation with a rapid ventricular response in surgical intensive care unit patients.

A comparative study of ivabradine and atenolol in patients with moderate mitral stenosis in sinus rhythm.

PubMed

Rajesh, Gopalan Nair; Sajeer, Kalathingathodika; Sajeev, Chakanalil Govindan; Bastian, Cicy; Vinayakumar, Desabandhu; Muneer, Kader; Haridasan, Vellani; Mathew, Dolly; George, Biju; Krishnan, Mangalath Narayanan

2016-01-01

Beta-blockers are frequently used in patients with mitral stenosis to control the heart rate and alleviate exercise-related symptoms. The objective of our study was to examine whether ivabradine was superior to atenolol for achieving higher exercise capacity in patients with moderate mitral stenosis in sinus rhythm. We also evaluated their effects on left ventricular myocardial performance index (MPI). Eighty-two patients with moderate mitral stenosis in sinus rhythm were randomized to receive ivabradine (n=42) 5mg twice daily or atenolol (n=40) 50mg daily for 6 weeks. Transthoracic echocardiography and treadmill test were performed at baseline and after completion of 6 weeks of treatment. Mean total exercise duration in seconds markedly improved in both study groups at 6 weeks (298.57±99.05s vs. 349.12±103.53s; p=0.0001 in ivabradine group, 290.90±92.42s vs. 339.90±99.84s; p=0.0001 in atenolol group). On head-to-head comparison, there was no significant change in improvement of exercise time between ivabradine and atenolol group (p=0.847). Left ventricular MPI did not show any significant change from baseline and at 6 weeks in both drug groups (49.8%±8% vs. 48.3%±7% in ivabradine group, 52.9%±10% vs. 50.9%±10% in atenolol groups; p=0.602). Ivabradine or atenolol can be used for heart rate control in patients with moderate mitral stenosis in sinus rhythm. Ivabradine is not superior to atenolol for controlling heart rate or exercise capacity. Left ventricular MPI was unaffected by either of the drugs. Copyright © 2015 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Transesophageal echocardiography (TEE) in atrial fibrillation.

PubMed

Thamilarasan, M; Klein, A L

2000-11-01

Transesophageal echocardiography has given new insight into the pathogenesis of the thromboembolic sequelae of AF and expanded the available therapeutic options. Studies to date indicate that TEE-guided cardioversion is a safe and reasonable approach when the clinical situation warrants prompt restoration of sinus rhythm. Whether widespread use of this strategy offers further benefit remains to be established, although there are theoretical advantages to such an approach. The potential for earlier cardioversion using a TEE-guided approach may facilitate the achievement and maintenance of sinus rhythm. In the long term, earlier restoration of sinus rhythm prevents adverse atrial remodeling, lowers embolic risk, and may improve cardiac performance and functional status. Thromboembolic sequelae (either cardioversion-related or as a result of chronic AF) remain the most devastating complications of AF. Every attempt to minimize this risk should be pursued aggressively. Information gathered from TEE has helped to elucidate the mechanisms responsible for postcardioversion embolism and has emphasized the importance of anticoagulation during and after the restoration of sinus rhythm. TEE also has the potential to further risk stratify patients with AF. Ultimately, a subset of patients may be identified who require more intense anticoagulation (i.e., those with dense SEC or thrombus, or persistent thrombus after prolonged anticoagulation) or in whom cardioversion may be deferred entirely. Likewise, TEE also may prove to be useful in identifying patients with a low-clinical risk profile who may be treated with aspirin alone and patients in whom warfarin may be superior. The results of the ACUTE study should help to further define the role of TEE in the management of patients with AF. Additional clinical studies are needed to address some of the issues that have been raised and to allow for optimal use of TEE in this patient population.

Effects of chronic omega-3 polyunsaturated fatty acid supplementation on human atrial mechanical function after reversion of atrial arrhythmias to sinus rhythm: reversal of tachycardia-mediated atrial cardiomyopathy with fish oils.

PubMed

Kumar, Saurabh; Sutherland, Fiona; Wheeler, Miriam; Heck, Patrick M; Lee, Geoffrey; Teh, Andrew W; Garg, Manohar L; Morgan, John G; Sparks, Paul B

2011-05-01

Atrial mechanical stunning is a form of tachycardia-mediated atrial cardiomyopathy that manifests after reversion of persistent atrial arrhythmias to sinus rhythm. This study sought to examine whether chronic omega-3 polyunsaturated fatty acid supplementation with fish oils can reverse atrial mechanical stunning. Patients undergoing reversion of persistent atrial fibrillation (AF) or atrial flutter (AFL) to sinus rhythm were randomized to a control group (n = 26) or an omega-3 group (n = 23). The latter were prescribed 6 g/day of fish oil for ≥1 month prior to the procedure. Parameters of left atrial appendage function were compared immediately before and immediately after reversion. After fish oil intake for a mean of 70 days, the following were noted favoring the omega-3 group among both AF and AFL patients: (1) 2-fold higher serum omega-3 levels (P < .001), (2) less mean decrease in emptying velocity (e.g., AF: 8% vs. 32%, P = .02), (3) less mean decrease in appendage emptying fraction (e.g., AFL: 7% vs. 60%, P = .002), (4) lower incidence of new or increased spontaneous echocardiographic contrast (e.g., AF: 11% vs. 62.5%, P = .003), and (5) lower incidence of atrial mechanical stunning (e.g., AFL: 20% vs. 100%, P = .001). Omega-3 intake conferred protection against stunning in a multivariable analysis (odds ratio 0.18, P = .02). Chronic fish oil ingestion in humans attenuates atrial mechanical stunning after reversion of atrial arrhythmias to sinus rhythm. This suggests that fish oils may target or even reverse underlying cellular and/or structural remodeling that occurs in response to persistent atrial arrhythmias. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

Rate versus rhythm control and outcomes in patients with atrial fibrillation and chronic kidney disease: data from the GUSTO-III Trial.

PubMed

Williams, Eric S; Thompson, Vivian P; Chiswell, Karen E; Alexander, John H; White, Harvey D; Ohman, E Magnus; Al-Khatib, Sana M

2013-01-01

Atrial fibrillation (AF) and chronic kidney disease (CKD) have both been shown to portend worse outcomes after acute myocardial infarction (MI); however, the benefit of a rhythm control strategy in patients with CKD post-MI is unclear. We prospectively studied 985 patients with new-onset AF post-MI in the GUSTO-III trial, of whom 413 (42%) had CKD (creatinine clearance < 60 mL/min). A rhythm control strategy, defined as the use of an antiarrhythmic medication and/or electrical cardioversion, was used in 346 (35%) of patients. A rhythm control strategy was used in 34% of patients with CKD and 36% of patients with no CKD. At hospital discharge, sinus rhythm was present in 487 (76%) of patients treated with a rate control strategy, vs. 276 (80%) in those treated with rhythm control (p = 0.20). CKD was associated with a lower odds of sinus rhythm at discharge (unadjusted OR 0.56, 95% CI 0.38-0.84, p < 0.001). However, in multivariable analyses, treatment with a rhythm control strategy was not associated with discharge rhythm (HR 1.068, 95% CI 0.69-1.66, p = 0.77), 30-day mortality (HR 0.78, 95% CI 0.54-1.12, p = 0.18) or mortality from day 30 to 1 year (HR 1.00, 95% CI 0.59-1.69, p = 0.99). CKD status did not significantly impact the relationship between rhythm control and outcomes. Treatment with a rhythm or rate control strategy does not signifi cantly impact short-term or long-term mortality in patients with post-MI AF, regardless of kidney disease status. Future studies to investigate the optimal management of AF in CKD patients are needed.

[Semi-automatic defibrillators does not always interpret heart rhythms correctly. Five patients were defibrillated despite non-shockable rhythms].

PubMed

Wangenheim, Burkard; Israelsson, Johan; Lindstaedt, Michael; Carlsson, Jörg

2015-08-04

Automated external defibrillators (AED) have become an important part of the »the chain of survival« in case of sudden cardiac arrest (SCA), where early defibrillation is lifesaving. The American Heart Association demands that AEDs have a specificity of >99 % to recognize normal sinus rhythm and >95 % for the other non-shockable rhythms. Reports on their performance in the field are scarce. We present five cases in which AED recommended shock for apparently non-shockable rhythms. This indicates the necessity to systematically reevaluate AED performance.

New Methods for the Analysis of Heartbeat Behavior in Risk Stratification

PubMed Central

Glass, Leon; Lerma, Claudia; Shrier, Alvin

2011-01-01

Developing better methods for risk stratification for tachyarrhythmic sudden cardiac remains a major challenge for physicians and scientists. Since the transition from sinus rhythm to ventricular tachycardia/fibrillation happens by different mechanisms in different people, it is unrealistic to think that a single measure will be adequate to provide a good index for risk stratification. We analyze the dynamical properties of ventricular premature complexes over 24 h in an effort to understand the underlying mechanisms of ventricular arrhythmias and to better understand the arrhythmias that occur in individual patients. Two dimensional density plots, called heartprints, correlate characteristic features of the dynamics of premature ventricular complexes and the sinus rate. Heartprints show distinctive characteristics in individual patients. Based on a better understanding of the natures of transitions from sinus rhythm to sudden cardiac and the mechanisms of arrhythmia prior to cardiac arrest, it should be possible to develop better methods for risk stratification. PMID:22144963

Impact of treatment crossovers on clinical outcomes in the rate and rhythm control strategies for atrial fibrillation: Insights from the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial.

PubMed

Maan, Abhishek; Zhang, Zheng; Qin, Ziling; Wang, Yanbing; Dudley, Samuel; Dabhadakar, Kaustubh; Refaat, Marwan; Mansour, Moussa; Ruskin, Jeremy N; Heist, E Kevin

2017-07-01

We investigated the rates and reasons for crossover to alternative treatment strategies and its impact on mortality in patients who were enrolled in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial. Over a mean follow-up period of 3.5 years, 842 patients underwent crossover to the alternative treatment arms in AFFIRM. The rate of crossover from rhythm to rate control (594/2,033, 29.2%) was more frequent than the rate of crossover from rate to rhythm control (248/2,027, 12.2%, P < 0.0001). The leading reasons for crossover from rhythm to rate control were failure to achieve or maintain sinus rhythm (272/594, 45.8%) and intolerable adverse effects (122/594, 20.5%). In comparison, the major reasons for crossover from rate to rhythm control were failure to control atrial fibrillation symptoms (159/248, 64.1%) and intolerable adverse effects (9/248, 3.6%). This difference in crossover pattern was statistically significant (P < 0.0001). There was a significantly decreased risk of all-cause mortality (adjusted HR: 0.61, 95% CI: 0.48-0.78, P < 0.0001) and cardiac mortality (adjusted hazard ratio [HR]: 0.61, 95% confidence interval [CI]: 0.43-0.88, P = 0.008) in the subgroup of patients who crossed over from rhythm to rate control as compared to those who continued in rhythm control. There was a nonsignificant trend toward decreased all-cause (adjusted HR: 0.76, 95% CI: 0.53-1.10, P = 0.14) and cardiac mortality (adjusted HR: 0.70, 95% CI: 0.42-1.18, P = 0.18) in patients who crossed over from rate to rhythm control as compared to those who continued rate control. © 2017 Wiley Periodicals, Inc.

A preliminary study on atrial epicardial mapping signals based on Graph Theory.

PubMed

Sun, Liqian; Yang, Cuiwei; Zhang, Lin; Chen, Ying; Wu, Zhong; Shao, Jun

2014-07-01

In order to get a better understanding of atrial fibrillation, we introduced a method based on Graph Theory to interpret the relations of different parts of the atria. Atrial electrograms under sinus rhythm and atrial fibrillation were collected from eight living mongrel dogs with cholinergic AF model. These epicardial signals were acquired from 95 unipolar electrodes attached to the surface of the atria and four pulmonary veins. Then, we analyzed the electrode correlations using Graph Theory. The topology, the connectivity and the parameters of graphs during different rhythms were studied. Our results showed that the connectivity of graphs varied from sinus rhythm to atrial fibrillation and there were parameter gradients in various parts of the atria. The results provide spatial insight into the interaction between different parts of the atria and the method may have its potential for studying atrial fibrillation. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

On-line telemetry: prospective assessment of accuracy in an all-volunteer emergency medical service system.

PubMed

Hollander, J E; Delagi, R; Sciammarella, J; Viccellio, P; Ortiz, J; Henry, M C

1995-04-01

To evaluate the need for on-line telemetry control in an all-volunteer, predominantly advanced emergency medical technician (A-EMT) ambulance system. Emergency medical service (EMS) advanced life support (ALS) providers were asked to transmit the ECG rhythms of monitored patients over a six-month period in 1993. The ECG rhythm interpretations of volunteer EMS personnel were compared with those of the on-line medical control physician. All discordant readings were reviewed by a panel of physicians to decide whether the misdiagnosis would have resulted in treatment aberrations had transmission been unavailable. Patients were monitored and rhythms were transmitted in 1,825 cases. 1,642 of 1,825 rhythms were correctly interpreted by the EMS providers (90%; 95% CI 89-91%). The accuracy of the EMS providers was dependent on the patient's rhythm (chi-square, p < 0.00001), the chief complaint (chi-square, p = 0.0001), and the provider's level of training (chi-square, p = 0.02). Correct ECG rhythm interpretations were more common when the out-of-hospital interpretation was sinus rhythm (95%), ventricular fibrillation (87%), paced rhythm (94%), or agonal rhythm (96%). The EMS providers were frequently incorrect when the out-of-hospital rhythm interpretation was atrial fibrillation/flutter (71%), supraventricular tachycardia (46%), ventricular tachycardia (59%), or atrioventricular block (50%). Of the 183 discordant cases, 124 (68%) involved missing a diagnosis of, or incorrectly diagnosing, atrial fibrillation/flutter. Review of the discordant readings identified 11 cases that could have resulted in treatment errors had the rhythms not been transmitted, one of which might have resulted in an adverse outcome. In this all-volunteer, predominantly A-EMT ALS system, patients with a field interpretation of a sinus rhythm do not require ECG rhythm transmission. Field interpretations of atrial fibrillation/flutter, supraventricular tachycardia, ventricular tachycardia, and atrioventricular blocks are frequently incorrect and should continue to be transmitted.

Effect of the Size of the Left Atrium on Sustained Sinus Rhythm in Patients Undergoing Mitral Valve Surgery and Concomitant Bipolar Radiofrequency Ablation for Atrial Fibrillation.

PubMed

Avdagić, Harun; Sijerčić Avdagić, Selma; Pirić Avdagić, Melika; Antonič, Miha

2017-12-01

Atrial fibrillation is associated with systemic embolization and complications due to anticoagulant therapy. Radiofrequency ablation has been established as an effective and safe method for the treatment of atrial fibrillation. The aim of this study was to evaluate the effect of the size of the left atrium on the outcome of surgical radiofrequency ablation. Forty patients scheduled for elective mitral valve surgery and radiofrequency ablation were enrolled in the study. Group 1 consisted of patients with a left atrium diameter ≤5 cm and group 2 of patients with left atrium diameter >5 cm. The primary endpoint of the study was stable sinus rhythm 6 months postoperatively. At 6 months postoperatively, sinus rhythm was present in significantly more group 1 patients as compared with group 2 patients, i.e. 15 (75%) vs. 8 (40%), p=0.025. Multivariate analysis proved the size of the left atrium to be an independent predictor of the radiofrequency ablation outcome. Accordingly, the size of the left atrium was demonstrated to be an important predictor of the outcome of radiofrequency ablation for atrial fibrillation. A lower cut-off value of surgical reduction of the atria than previously reported should be considered in order to improve the radiofrequency ablation outcome.

Mechanism of reentry induction by a 9-V battery in rabbit ventricles

PubMed Central

Burton, Rebecca A. B.; Kalla, Manish; Nanthakumar, Kumaraswamy; Plank, Gernot; Bub, Gil; Vigmond, Edward J.

2014-01-01

Although the application of a 9-V battery to the epicardial surface is a simple method of ventricular fibrillation induction, the fundamental mechanisms underlying this process remain unstudied. We used a combined experimental and modelling approach to understand how the interaction of direct current (DC) from a battery may induce reentrant activity within rabbit ventricles and its dependence on battery application timing and duration. A rabbit ventricular computational model was used to simulate 9-V battery stimulation for different durations at varying onset times during sinus rhythm. Corresponding high-resolution optical mapping measurements were conducted on rabbit hearts with DC stimuli applied via a relay system. DC application to diastolic tissue induced anodal and cathodal make excitations in both simulations and experiments. Subsequently, similar static epicardial virtual electrode patterns were formed that interacted with sinus beats but did not induce reentry. Upon battery release during diastole, break excitations caused single ectopics, similar to application, before sinus rhythm resumed. Reentry induction was possible for short battery applications when break excitations were slowed and forced to take convoluted pathways upon interaction with refractory tissue from prior make excitations or sinus beats. Short-lived reentrant activity could be induced for battery release shortly after a sinus beat for longer battery applications. In conclusion, the application of a 9-V battery to the epicardial surface induces reentry through a complex interaction of break excitations after battery release with prior induced make excitations or sinus beats. PMID:24464758

Mechanism of reentry induction by a 9-V battery in rabbit ventricles.

PubMed

Bishop, Martin J; Burton, Rebecca A B; Kalla, Manish; Nanthakumar, Kumaraswamy; Plank, Gernot; Bub, Gil; Vigmond, Edward J

2014-04-01

Although the application of a 9-V battery to the epicardial surface is a simple method of ventricular fibrillation induction, the fundamental mechanisms underlying this process remain unstudied. We used a combined experimental and modelling approach to understand how the interaction of direct current (DC) from a battery may induce reentrant activity within rabbit ventricles and its dependence on battery application timing and duration. A rabbit ventricular computational model was used to simulate 9-V battery stimulation for different durations at varying onset times during sinus rhythm. Corresponding high-resolution optical mapping measurements were conducted on rabbit hearts with DC stimuli applied via a relay system. DC application to diastolic tissue induced anodal and cathodal make excitations in both simulations and experiments. Subsequently, similar static epicardial virtual electrode patterns were formed that interacted with sinus beats but did not induce reentry. Upon battery release during diastole, break excitations caused single ectopics, similar to application, before sinus rhythm resumed. Reentry induction was possible for short battery applications when break excitations were slowed and forced to take convoluted pathways upon interaction with refractory tissue from prior make excitations or sinus beats. Short-lived reentrant activity could be induced for battery release shortly after a sinus beat for longer battery applications. In conclusion, the application of a 9-V battery to the epicardial surface induces reentry through a complex interaction of break excitations after battery release with prior induced make excitations or sinus beats.

Association of the CHA2DS2-VASc score with left atrial spontaneous echo contrast: a cross-sectional study of patients with rheumatic mitral stenosis in sinus rhythm.

PubMed

Belen, Erdal; Ozal, Ender; Pusuroglu, Hamdi

2016-09-01

Mitral valve stenosis is a common manifestation of chronic rheumatic heart disease. In rheumatic mitral valve stenosis (RMVS) patients, left atrial spontaneous echo contrast (LASEC) is an independent predictor of thromboembolism risk. While the anticoagulant therapy algorithm for atrial fibrillation patients is clear, the clinical tools determining high-risk patients in sinus rhythm are insufficient. Our aim is to examine the relationship between CHA2DS2-VASc score in RMVS patients in sinus rhythm and the presence of LASEC. The patients with RMVS upon presentation to the cardiology polyclinic were included in this cross-sectional study consecutively, and CHA2DS2-VASc scores were calculated. All patients were evaluated with transthoracic and transesophageal echocardiography and were divided into two groups as those with and without LASEC. The total number of patients was 265, with LASEC determined in 97 (36.6 %) and not determined in 168 (63.4 %). No significant differences in terms of age, gender, and body mass index were found between the groups. Patients with LASEC had higher mean CHA2DS2-VASc score than patients without LASEC (2.10 ± 1.21 vs. 1.11 ± 0.7, respectively; p < 0.001). In the multivariate logistic regression analysis, it has been determined that there is an independent association between the existence of LASEC and CHA2DS2-VASc score (OR 3.176, CI 1.937-5.206; p < 0.001). The ROC analysis revealed that CHA2DS2-VASc score 2 or more predicted presence of LASEC with a sensitivity of 71 % and a specificity of 82 % (AUC 0.746, 95 % CI 0.682-0.810). The CHA2DS2-VASc score could be useful marker to detect prothrombotic state in patients with RMVS in sinus rhythm.

Increased α-Actinin-2 Expression in the Atrial Myocardium of Patients with Atrial Fibrillation Related to Rheumatic Heart Disease.

PubMed

Zhang, Lei; Zhang, Nan; Tang, Xuejiao; Liu, Fajin; Luo, Suxin; Xiao, Hua

Atrial fibrosis, a marker of atrial structural remodeling, plays a critical role in atrial fibrillation (AF). α- Actinin-2 is associated with structural remodeling related to stretching. The transforming growth factor-β1 (TGF-β1)/Smad pathway plays an important role in atrial fibrosis. We investigated the effects of the TGF-β1/Smad signaling pathway on α-actinin-2 in atrial fibrosis in patients with AF. Forty-one right atrial specimens obtained from patients with rheumatic heart disease (RHD) were divided into a chronic (c)AF group, i.e. RHD + cAF (n = 29), and a sinus rhythm group, i.e. RHD + sinus rhythm (n = 12). Patients with congenital heart disease (CHD) and sinus rhythm who underwent heart surgery served as controls (n = 10). Fibrosis was assessed by histological examination, and expression of α-actinin-2, TGF-β1 and Smad2/phosphorylated Smad2 (p-Smad2) was evaluated by immunohistochemistry, quantitative real-time PCR and Western blotting. In rat atrial fibroblasts treated with TGF-β1, the collagen content was measured using hydroxyproline detection, and α-actinin-2 and p-Smad2 were evaluated by semiquantitative reverse-transcription PCR and Western blotting. The histology results revealed a significant increase in atrial fibrosis in AF patients. The collagen content, mRNA and protein expression levels of α-actinin-2 and the components of the TGF-β1/Smad signaling pathway were significantly gradually increased in the CHD + sinus rhythm, RHD + sinus rhythm and RHD + cAF groups (p < 0.05). The mRNA and protein levels of α-actinin-2 and TGF-β1 in RHD patients were positively correlated with the collagen volume fraction. A positive correlation between the expression of α-actinin-2 and TGF-β1 was also observed. In rat atrial fibroblasts treated with TGF-β1, the collagen content was greater than that in the control group (p < 0.05), and the expression levels of α- actinin-2 and p-Smad2 were also upregulated (p < 0.05). α-Actinin-2 expression was increased in the atrial tissues of patients with AF secondary to RHD. α-Actinin-2 was upregulated via the TGF-β1/Smad pathway in atrial fibroblasts, which suggests that it may be involved in TGF-β1/Smad pathway-induced atrial fibrosis in patients with AF. © 2016 S. Karger AG, Basel.

Atrial Fibrillation in Heart Failure With Preserved Ejection Fraction: Association With Exercise Capacity, Left Ventricular Filling Pressures, Natriuretic Peptides, and Left Atrial Volume.

PubMed

Lam, Carolyn S P; Rienstra, Michiel; Tay, Wan Ting; Liu, Licette C Y; Hummel, Yoran M; van der Meer, Peter; de Boer, Rudolf A; Van Gelder, Isabelle C; van Veldhuisen, Dirk J; Voors, Adriaan A; Hoendermis, Elke S

2017-02-01

This study sought to study the association of atrial fibrillation (AF) with exercise capacity, left ventricular filling pressure, natriuretic peptides, and left atrial size in heart failure with preserved ejection fraction (HFpEF). The diagnosis of HFpEF in patients with AF remains a challenge because both contribute to impaired exercise capacity, and increased natriuretic peptides and left atrial volume. We studied 94 patients with symptomatic heart failure and left ventricular ejection fractions ≥45% using treadmill cardiopulmonary exercise testing and right- and/or left-sided cardiac catheterization with simultaneous echocardiography. During catheterization, 62 patients were in sinus rhythm, and 32 patients had AF. There were no significant differences in age, sex, body size, comorbidities, or medications between groups; however, patients with AF had lower peak oxygen consumption (VO 2 ) compared with those with sinus rhythm (10.8 ± 3.1 ml/min/kg vs. 13.5 ± 3.8 ml/min/kg; p = 0.002). Median (25th to 75th percentile) N-terminal pro-B-type natriuretic peptide (NT-proBNP) was higher in AF versus sinus rhythm (1,689; 851 to 2,637 pg/ml vs. 490; 272 to 1,019 pg/ml; p < 0.0001). Left atrial volume index (LAVI) was higher in AF than sinus rhythm (57.8 ± 17.0 ml/m 2 vs. 42.5 ± 15.1 ml/m 2 ; p = 0.001). Invasive hemodynamics showed higher mean pulmonary capillary wedge pressure (PCWP) (19.9 ± 3.7 vs. 15.2 ± 6.8) in AF versus sinus rhythm (all p < 0.001), with a trend toward higher left ventricular end-diastolic pressure (17.7 ± 3.0 mm Hg vs. 15.7 ± 6.9 mm Hg; p = 0.06). After adjusting for clinical covariates and mean PCWP, AF remained associated with reduced peak VO 2 increased log NT-proBNP, and enlarged LAVI (all p ≤0.005). AF is independently associated with greater exertional intolerance, natriuretic peptide elevation, and left atrial remodeling in HFpEF. These data support the application of different thresholds of NT-proBNP and LAVI for the diagnosis of HFpEF in the presence of AF versus the absence of AF. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Electrophysiological characteristics of the Marshall bundle in humans

PubMed Central

Han, Seongwook; Joung, Boyoung; Scanavacca, Mauricio; Sosa, Eduardo; Chen, Peng-Sheng; Hwang, Chun

2010-01-01

BACKGROUND Marshall bundles (MBs) are the muscle bundles within the ligament of Marshall. OBJECTIVE This trial sought to the electrophysiological characteristics of the MB and the anatomical connections between MB and left atrium (LA) in patients with persistent atrial fibrillation (AF). METHODS We enrolled 72 patients (male:female 59:13, age 59.9 ± 9.4 years) who underwent MB mapping and ablation for AF. MB mapping was done via an endocardial or epicardial approach during sinus rhythm and AF. RESULTS Recordings were successful in 64 of 72 patients (89%). A single connection was noted in 11 of 64 patients between the MB and the coronary sinus (CS) muscle sleeves. The MB recordings showed distinct MB potentials with a proximal-to-distal activation pattern during sinus rhythm. During AF, organized passive activations and dissociated slow MB ectopic activities were commonly observed in this type of connection. Double connections to both CS and LA around left pulmonary veins were noted in 23 of 64 patients (36%). After the ablation of the distal connection, MB recording showed typical double potentials as in single connection. Multiple connections were noted in 30 of 64 patients (47%). During sinus rhythm, the earliest activation was in the middle of the MB. The activation patterns were irregular and variable in each patient. During AF, rapid and fractionated complex activations were noted in all patients of this group. CONCLUSION We documented 3 different types of MB–LA connections. Rapid and fractionated activations were most commonly observed in the MB that had multiple LA connections. PMID:20188860

Electrocardiographic parameters of captive lions (Panthera leo) and tigers (Panthera tigris) immobilized with ketamine plus xylazine.

PubMed

Larsson, Maria Helena M A; Coelho, Fernanda M; Oliveira, Valéria M C; Yamaki, Fernanda L; Pereira, Guilherme G; Soares, Elaine C; Fedullo, José Daniel L; Pereira, Roberto C; Ito, F H

2008-09-01

Twenty-seven healthy captive lions (Panthera leo) and 13 healthy captive tigers (Panthera tigris) from São Paulo Zoo (Fundação Parque Zoológico de Sã Paulo, São Paulo, Brazil) collection were selected for this study. They were anesthetized with ketamine (10 mg/kg) combined with xylazine (1-2 mg/kg) for physical examinations, hematologic and serum chemical analysis and electrocardiogram recording. The main aim of this research was to gather initial information about normal electrocardiographic parameters of large felids. Standard P-QRS-T deflections on leads described for domestic carnivores were analyzed, and they did not greatly differ from those of large felids, taking into account the greater weight and corporal mass of large felids. Heart rate of lions ranged from 42 to 76 beats per minute (bpm). Heart rate of tigers ranged from 56 to 97 bpm. In both species, the most common rhythm detected was normal sinus rhythm followed by sinus arrhythmia; wandering pacemaker was also observed with normal sinus rhythm or sinus arrhythmia. Mean electrical axis lay between +60 degrees and +120 degrees. QRS complexes were predominantly positive in leads DI, DII, DIII, and AVF, and negative in AVR and AVL. This study provides insights into normal electrocardiograms of large felids. Wider investigations on the same subject are necessary to establish criteria for the recognition of abnormalities in these species and should include other anesthetic drug(s) combinations and reports of electrocardiographic features of animals with cardiac disease and electrolytes disturbances.

Clinically oriented device programming in bradycardia patients: part 1 (sinus node disease). Proposals from AIAC (Italian Association of Arrhythmology and Cardiac Pacing).

PubMed

Ziacchi, Matteo; Palmisano, Pietro; Biffi, Mauro; Ricci, Renato P; Landolina, Maurizio; Zoni-Berisso, Massimo; Occhetta, Eraldo; Maglia, Giampiero; Botto, Gianluca; Padeletti, Luigi; Boriani, Giuseppe

2018-04-01

: Modern pacemakers have an increasing number of programable parameters and specific algorithms designed to optimize pacing therapy in relation to the individual characteristics of patients. When choosing the most appropriate pacemaker type and programing, the following variables must be taken into account: the type of bradyarrhythmia at the time of pacemaker implantation; the cardiac chamber requiring pacing, and the percentage of pacing actually needed to correct the rhythm disorder; the possible association of multiple rhythm disturbances and conduction diseases; the evolution of conduction disorders during follow-up. The goals of device programing are to preserve or restore the heart rate response to metabolic and hemodynamic demands; to maintain physiological conduction; to maximize device longevity; to detect, prevent, and treat atrial arrhythmia. In patients with sinus node disease, the optimal pacing mode is DDDR. Based on all the available evidence, in this setting, we consider appropriate the activation of the following algorithms: rate responsive function in patients with chronotropic incompetence; algorithms to maximize intrinsic atrioventricular conduction in the absence of atrioventricular blocks; mode-switch algorithms; algorithms for autoadaptive management of the atrial pacing output; algorithms for the prevention and treatment of atrial tachyarrhythmias in the subgroup of patients with atrial tachyarrhythmias/atrial fibrillation. The purpose of this two-part consensus document is to provide specific suggestions (based on an extensive literature review) on appropriate pacemaker setting in relation to patients' clinical features.

Atrial fibrillation with wide QRS tachycardia and undiagnosed Wolff-Parkinson-White syndrome: diagnostic and therapeutic dilemmas in a pediatric patient.

PubMed

Panduranga, Prashanth; Al-Farqani, Abdullah; Al-Rawahi, Najib

2012-11-01

A 10-year-old girl presented to the emergency department of a regional hospital with 1 episode of generalized tonic-clonic seizures. Postictal monitoring followed by a 12-lead electrocardiogram showed fast atrial fibrillation with intermittent wide QRS regular tachycardia. Immediately following this, her rhythm changed to wide QRS irregular tachycardia without hemodynamic compromise. She was suspected to have ventricular tachycardia and was treated with intravenous amiodarone with cardioversion to sinus rhythm. Subsequent electrocardiogram in sinus rhythm showed typical features of manifest Wolff-Parkinson-White (WPW) accessory pathway. This case illustrates the diagnostic and therapeutic dilemmas in patients with atrial fibrillation, wide QRS tachycardia, and undiagnosed WPW syndrome with antidromic conduction of atrial arrhythmias through the accessory pathway. Furthermore, this case demonstrates that undiagnosed wide QRS tachycardias need to be treated with drugs acting on the accessory pathway, thus keeping in mind underlying WPW syndrome as a possibility to avoid potentially catastrophic events.

[Atypical sinus node dysfunction. Usefulness of implantable Holter. A case report].

PubMed

Martí Almor, J; Delclòs Urgell, J; Bruguera Cortada, J

2001-12-01

We present an 84 year-old female patient with repeated syncopes/presyncopes in the last nine years. All diagnosis tests were negative, including ECG, 24-hour Holter, tilt table test and EP study. Therefore, a subcutaneous insertable loop recorder was implanted (Reveal). The recording of three episodes showed the association of presyncope with the onset of atrial fibrilation and, in two syncopes, with an atrial pause between AF episodes. Probably an abnormal prolonged sinus node recovery time (more than 6 s) allowed AF to restart before the sinus rhythm.

Seckel syndrome with severe sinus bradycardia.

PubMed

Ramasamy, Chandramohan; Satheesh, Santhosh; Selvaraj, Raja

2015-03-01

Seckel syndrome is an uncommon form of microcephalic dwarfism. The authors report a young boy with Seckel syndrome who presented with severe sinus bradycardia with symptoms of syncope and presyncope. Implantation of a permanent pacemaker was necessary in view of the severe symptoms. Although uncommon, cardiac abnormalities have been rarely reported in Seckel syndrome. This is the one of the few reports of rhythm abnormalities in this condition.

Chemical cardioversion of recent-onset atrial fibrillation in the emergency department using vernakalant hydrochloride achieves safe and rapid restoration of sinus rhythm and facilitates same day discharge.

PubMed

Stoneman, P; Gilligan, P; Mahon, P; Sheahan, R

2017-11-01

Vernakalant hydrochloride is a rapid-acting antiarrhythmic drug licensed in the EU since 2010 for the conversion of recent-onset atrial fibrillation with proven efficacy and safety when compared with placebo and amiodarone in randomized clinical trials. The aim of our study was to determine the feasibility of same day discharge (following 2 h monitoring) from the emergency department after successful cardioversion using vernakalant hydrochloride. Patients with recent-onset atrial fibrillation treated in the emergency department of a large Dublin academic teaching hospital. Patients received a maximum of two weight based 10 min infusions of vernakalant. Hypotensive events (>30% initial blood pressure), arrhythmias, conversion rates, and time to conversion were recorded. Sinus rhythm was restored in 35 out of 42 patients (83%) in an average of 8.8 min (median 8 min), average CHA2DS2-VASc of 0.92, HAS-BLED of 0.21 and average symptoms duration of 12 h. There were no hypotensive or arrhythmogenic events. 41 out of 42 patients were discharged after 2 h of monitoring. Vernakalant hydrochloride has provided a quick, safe, and practical means of achieving rapid restoration of sinus rhythm in our ED population with stable recent-onset AF who would otherwise not have undergone routine electrically cardioversion and same day discharge.

Prevalence and mechanism of rotor activation identified during atrial fibrillation by noncontact mapping: Lack of evidence for a role in the maintenance of atrial fibrillation.

PubMed

Yamabe, Hiroshige; Kanazawa, Hisanori; Ito, Miwa; Kaneko, Shozo; Ogawa, Hisao

2016-12-01

It remains unclear whether atrial fibrillation (AF) is maintained by the rotor. We evaluated the role of the rotor and examined its mechanism. Among 75 patients with AF (60 paroxysmal, 15 persistent AF) who underwent 3-dimensional noncontact left atrial mapping during AF, we examined the prevalence and location of rotor activation and elucidated its mechanism. Catheter ablation was performed in a stepwise fashion (linear roof lesion and complex fractionated atrial electrogram ablation after pulmonary vein [PV) isolation) until AF termination. Rotor activation was observed in 11 patients (14.7%; 10 paroxysmal and 1 persistent AF) (tachycardia cycle length 160.0 ± 19.8 ms). Rotors were observed transiently (duration 6128 ± 9094 ms) during AF at the roof (n = 5), septum (n = 3), and ostium of the left superior PV (n = 3). Five rotors circulated in clockwise and 6 in counterclockwise directions. The length of the block line at the center of the rotor was 15.2 ± 6.9 mm. The electrograms at the block line showed low-amplitude multiple deflections (n = 7) or double potentials (n = 4), and the amplitudes during rotor activation were significantly lower than those during sinus rhythm (0.27 ± 0.18 mV vs 1.22 ± 0.92 mV; P < .01). No conduction disturbances were found during sinus rhythm, suggesting that the central line of block was formed functionally. AF was terminated by PV isolation alone without additional lesions in patients with rotors. Functionally formed rotor activation was observed during AF in a limited number of patients. These rotor activations may not be related to AF maintenance, but rather may reflect a transient organization of random propagation. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

[A case report of Ebstein's anomaly treated with Hetzer's procedure].

PubMed

Sako, H; Hadama, T; Shigemitsu, O; Miyamoto, S; Anai, H; Wada, T; Iwata, E; Mori, Y; Soeda, T; Takakura, K

2001-02-01

A 27-year-old male who had been diagnosed with Ebstein's anomaly was admitted with uncontrollable congestive heart failure. The echocardiogram revealed severe tricuspid valve incompetence and the electrocardiogram showed atrial fibrillation. He underwent Hetzer's repair procedure for tricuspid valve incompetence and Minzioni's right atrial isolation technique to restore sinus rhythm. His congestive heart failure quickly disappeared and sinus rhythm was restored after operation. He was discharged 3 weeks postoperatively and remains well 22 months after his operation. Hetzer's technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. We conclude that Hetzer's procedure is an effective operation for Ebstein's anomaly.

Role of Echocardiography in the Management and Prognosis of Atrial Fibrillation

PubMed Central

Silverman, David I; Ayirala, Srilatha R; Manning, Warren J

2012-01-01

Echocardiography plays a longstanding and vital role in the management of atrial fibrillation (AF). Advances in 2D imaging, Doppler echocardiography and strain imaging have all contributed to major progress in AF treatment. Echocardiographically measured left atrial (LA) volume is a powerful predictor of maintenance of sinus rhythm following cardioversion as well as risk of thrombus formation and thromboembolism. Doppler derived parameters of atrial mechanical function including atrial ejection force provide related prognostic information. Transesophageal echocardiocardiograpy (TEE) guided cardioversion of AF allows for rapid conversion to sinus rhythm without prolonged oral anticoagulation, and TEE serves as a useful tool during catheter ablation of AF and atrial flutter. Newer measures derived from speckle tracking offer great promise in further improving the care of patients with AF. PMID:28496715

Relevance of Conduction Disorders in Bachmann's Bundle During Sinus Rhythm in Humans.

PubMed

Teuwen, Christophe P; Yaksh, Ameeta; Lanters, Eva A H; Kik, Charles; van der Does, Lisette J M E; Knops, Paul; Taverne, Yannick J H J; van de Woestijne, Pieter C; Oei, Frans B S; Bekkers, Jos A; Bogers, Ad J J C; Allessie, Maurits A; de Groot, Natasja M S

2016-05-01

Bachmann's bundle (BB) is considered to be the main route of interatrial conduction and to play a role in development of atrial fibrillation (AF). The goals of this study are to characterize the presence of conduction disorders in BB during sinus rhythm and to study their relation with AF. High-resolution epicardial mapping (192 unipolar electrodes, interelectrode distance: 2 mm) of sinus rhythm was performed in 185 patients during coronary artery bypass surgery of whom 13 had a history of paroxysmal AF. Continuous rhythm monitoring was used to detect postoperative AF during the first 5 postoperative days. In 67% of the patients, BB was activated from right to left; in the remaining patients from right and middle (21%), right, central, and left (8%), or central (4%) site. Mean effective conduction velocity was 89 cm/s. Conduction block was present in most patients (75%; median 1.1%, range 0-12.8) and was higher in patients with paroxysmal AF compared with patients without a history of AF (3.2% versus 0.9%; P=0.03). A high amount of conduction block (>4%) was associated with de novo postoperative AF (P=0.02). Longitudinal lines of conduction block >10 mm were also associated with postoperative AF (P=0.04). BB may be activated through multiple directions, but the predominant route of conduction is from right to left. Conduction velocity across BB is around 90 cm/s. Conduction is blocked in both longitudinal and transverse direction in the majority of patients. Conduction disorders, particularly long lines of longitudinal conduction block, are more pronounced in patients with AF episodes. © 2016 American Heart Association, Inc.

A novel application for the detection of an irregular pulse using an iPhone 4S in patients with atrial fibrillation.

PubMed

McManus, David D; Lee, Jinseok; Maitas, Oscar; Esa, Nada; Pidikiti, Rahul; Carlucci, Alex; Harrington, Josephine; Mick, Eric; Chon, Ki H

2013-03-01

Atrial fibrillation (AF) is common and associated with adverse health outcomes. Timely detection of AF can be challenging using traditional diagnostic tools. Smartphone use is increasing and may provide an inexpensive and user-friendly means to diagnoseAF. To test the hypothesis that a smartphone-based application could detect an irregular pulse fromAF. Seventy-six adults with persistent AF were consented for participation in our study. We obtained pulsatile time series recordings before and after cardioversion using an iPhone 4S camera. A novel smartphone application conducted real-time pulse analysis using 2 statistical methods: root mean square of successive RR difference (RMSSD/mean) and Shannon entropy (ShE). We examined the sensitivity, specificity, and predictive accuracy of both algorithms using the 12-lead electrocardiogram as the gold standard. RMSDD/mean and ShE were higher in participants in AF than in those with sinus rhythm. The 2 methods were inversely related to AF in regression models adjusting for key factors including heart rate and blood pressure (beta coefficients per SD increment in RMSDD/mean and ShE were-0.20 and-0.35; P<.001). An algorithm combining the 2 statistical methods demonstrated excellent sensitivity (0.962), specificity (0.975), and accuracy (0.968) for beat-to-beat discrimination of an irregular pulse during AF from sinus rhythm. In a prospectively recruited cohort of 76 participants undergoing cardioversion for AF, we found that a novel algorithm analyzing signals recorded using an iPhone 4S accurately distinguished pulse recordings during AF from sinus rhythm. Data are needed to explore the performance and acceptability of smartphone-based applications for AF detection. Copyright © 2013 Heart Rhythm Society. All rights reserved.

Syncope cluster in a patient with vasovagal history.

PubMed

Zyśko, Dorota; Sokalski, Leszek; Gajek, Jacek; Loboz-Grudzień, Krystyna

2010-10-01

We report a case of a 55 year-old man with a history of vasovagal syncope who experienced six unexpected syncopal events over the course of two hours. Two of these occurred in the supine position during ECG monitoring, which showed a long-lasting sinus pause. Before the last syncopal episode, the ECG recording was started at the moment when the patient had the recurrence of presyncopal symptoms. Recordings showed sinus rhythm slowing for 12 s and then sinus arrest lasting for 29 s. A thorough clinical examination revealed no relevant abnormalities. The patient was treated with a permanent pacemaker implantation.

Safety aspects for public access defibrillation using automated external defibrillators near high-voltage power lines.

PubMed

Schlimp, C J; Breiteneder, M; Lederer, W

2004-05-01

Automated external defibrillators (AEDs) must combine easy operability and high-quality diagnosis even under unfavorable conditions. This study determined the influence of electromagnetic interference caused by high-voltage power lines with 16.7-Hz alternating current on the quality of AEDs' rhythm analysis. Two AEDs frequently used in Austria were tested near high-voltage power lines (15 kV or 110 kV, alternating current with 16.7 Hz). The defibrillation electrodes were attached either to a proband with true sinus rhythm or to a resuscitation dummy with generated sinus rhythm, ventricular fibrillation, ventricular tachycardia or asystole. Electromagnetic interference was much more prominent in a human's than in a dummy's electrocardiogram and depended on the position of the electrodes and cables in relation to the power line. Near high-voltage power lines the AEDs showed a significant operational fault. One AED interpreted the interference as a motion artifact, even when underlying rhythms were clearly detectable. The other AED interpreted 16.7-Hz oscillation as ventricular fibrillation with consequent shock advice when no underlying rhythm was detected. The tested AEDs neither filter nor recognize a technical interference of 16.7 Hz caused by 15-kV power lines above railway tracks or 110-kV overland power lines, as run by railway companies in Austria, Germany, Norway, Sweden and Switzerland. These failures in AEDs' algorithms for rhythm analysis may cause substantial harm to patients undergoing public access defibrillation. The proper function of AEDs needs to be reconsidered to guarantee patients' safety near high-voltage power lines.

Predicting the risk of sudden cardiac death.

PubMed

Lerma, Claudia; Glass, Leon

2016-05-01

Sudden cardiac death (SCD) is the result of a change of cardiac activity from normal (typically sinus) rhythm to a rhythm that does not pump adequate blood to the brain. The most common rhythms leading to SCD are ventricular tachycardia (VT) or ventricular fibrillation (VF). These result from an accelerated ventricular pacemaker or ventricular reentrant waves. Despite significant efforts to develop accurate predictors for the risk of SCD, current methods for risk stratification still need to be improved. In this article we briefly review current approaches to risk stratification. Then we discuss the mathematical basis for dynamical transitions (called bifurcations) that may lead to VT and VF. One mechanism for transition to VT or VF involves a perturbation by a premature ventricular complex (PVC) during sinus rhythm. We describe the main mechanisms of PVCs (reentry, independent pacemakers and abnormal depolarizations). An emerging approach to risk stratification for SCD involves the development of individualized dynamical models of a patient based on measured anatomy and physiology. Careful analysis and modelling of dynamics of ventricular arrhythmia on an individual basis will be essential in order to improve risk stratification for SCD and to lay a foundation for personalized (precision) medicine in cardiology. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

[Dopplerography of the large hepatic veins in the diagnosis of tricuspid valve insufficiency].

PubMed

Korytnikov, K I; Martyniuk, A D; Pustovit, L K

1991-01-01

During pulse dopplerography of the large hepatic veins in patients with tricuspid valve failure, the differences in the shape of the spectrum of Doppler's frequencies were revealed as dependent on cardiac rhythm. In sinus rhythm, the curve of the systolic flow is recordable beneath the baseline, in atrial fibrillation, over the baseline. In scanning of the large hepatic veins in patients with tricuspid valve failure, the shape of the curves of the spectrum of Doppler's frequencies coincides with the shape of the curves of liver pulsation. Tricuspid valve failure in sinus rhythm leads to a decrease of the maximum velocity of the systolic flow in the hepatic veins. There is a close correlation between the maximum velocity of the systolic flow of tricuspid regurgitation and the maximum velocity of the systolic flow in the large hepatic veins. Pulse dopplerography of the large hepatic veins is a safe enough method of the diagnosis of tricuspid valve failure and can be used in difficult cases when analysing the tricuspid blood flow from standard projections.

Effects of linear ablation at the isthmus between the tricuspid annulus and inferior vena cava for atrial flutter on autonomic nervous activity: analysis of heart rate variability.

PubMed

Li, Aiyan; Kuga, Keisuke; Suzuki, Akihiro; Endo, Masae; Niho, Bumpei; Enomoto, Mami; Kanemoto, Miyako; Yamaguchi, Iwao

2002-01-01

Heart rate is largely affected by the autonomic nervous system. However, little is known about the anatomic pathway of autonomic nerve fibers innervating the sinus node. The present study: (1) evaluates the effects of cavotricuspid isthmus ablation for common atrial flutter (AFL) on autonomic nervous function by using heart rate variability analysis, and (2) investigates the distribution of autonomic nerve pathways innervating the sinus node. Twelve patients with paroxysmal common atrial flutter who maintained sinus rhythm both before and after radiofrequency ablation were selected for the study. Holter ambulatory recordings were performed before and after (2.3 +/- 1.0 days) radiofrequency ablation of cavotricuspid isthmus. Heart rate and time domain (SDANN, rMSSD, pNN50) and frequency domain (low frequency (LF), high frequency (HF), LF/HF) analysis of heart rate variability were compared before and after ablation. Mean heart rate did not change significantly after ablation (59 +/- 6 vs 61 +/- 9 beats/min); parasympathetic indices of heart rate variability (SDANN, rMSSD, pNN50, HF) did not change significantly (110 +/- 37 vs 117 +/- 20 ms; 32 +/- 21 vs 28 +/- 9 ms; 4.8 +/- 0.9 vs 4.7 +/- 0.71n(ms2)); and sympathetic indices of heart rate variability (LF/HF) did not change significantly (1.1 +/- 0.2 vs 1.2 +/- 0.1). Cavotricuspid isthmus ablation for atrial flutter did not significantly change heart rate and heart rate variability because parasympathetic and sympathetic fibers innervating the sinus node are scarce in this region.

Supraventricular tachycardia after fenoterol inhalation: report of two cases.

PubMed

Hung, Yu-Fa; Yang, Winnie; Chang, Mei-Ling

2003-01-01

Supraventricular tachycardia (SVT) following fenoterol inhalation in metered-dose inhaler (MDI) has never been reported. We report two cases of SVT after fenoterol inhalation in MDI. Case one was a 4-year-old boy who had asthma since early childhood. Paroxysmal supraventricular tachycardia (PSVT) was found after fenoterol inhalation (MDI), which returned to normal sinus rhythm following adenosine injection. The other one was a 9-year-old male who also had asthma since early childhood. He suffered from attacks of PSVT four times after fenoterol inhalation within one year. After verapamil injection and vagal maneuvers, PSVT was converted to normal sinus rhythm. There were no other episodes of SVT after discontinuing usage of fenoterol inhalation for 2 years in the follow-up. We report these two cases to remind pediatricians that cardiac arrhythmias should be evaluated following fenoterol inhalation (MDI).

Detection of ventricular fibrillation from multiple sensors

NASA Astrophysics Data System (ADS)

Lindsley, Stephanie A.; Ludeman, Lonnie C.

1992-07-01

Ventricular fibrillation is a potentially fatal medical condition in which the flow of blood through the body is terminated due to the lack of an organized electric potential in the heart. Automatic implantable defibrillators are becoming common as a means for helping patients confronted with repeated episodes of ventricular fibrillation. Defibrillators must first accurately detect ventricular fibrillation and then provide an electric shock to the heart to allow a normal sinus rhythm to resume. The detection of ventricular fibrillation by using an array of multiple sensors to distinguish between signals recorded from single (normal sinus rhythm) or multiple (ventricular fibrillation) sources is presented. An idealistic model is presented and the analysis of data generated by this model suggests that the method is promising as a method for accurately and quickly detecting ventricular fibrillation from signals recorded from sensors placed on the epicardium.

Left atrial isolation associated with mitral valve operations.

PubMed

Graffigna, A; Pagani, F; Minzioni, G; Salerno, J; Viganò, M

1992-12-01

Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent mitral valve operations. From May 1989 to September 1991, 62 patients underwent mitral valve operations (group I); 19, mitral valve operations and DeVega tricuspid annuloplasty (group II); 15, mitral and aortic operations (group III); and 4, mitral and aortic operations and DeVega tricuspid annuloplasty (group IV). Left atrial isolation was performed, prolonging the usual left paraseptal atriotomy toward the left fibrous trigone anteriorly and the posteromedial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesions were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 patients (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (group I, 80.7%; group II, 68.5%; group III, 86.7%; group IV, 75%; p = not significant). Three late deaths (3.1%) were registered. Long-term results show persistence of sinus rhythm in 71% of group I, 61.2% of group II, 85.8% of group III, and 100% of group IV. The unique risk factor for late recurrence of atrial fibrillation was found to be preoperative atrial fibrillation longer than 6 months. Due to the satisfactory success rate in recovering sinus rhythm, we suggest performing left atrial isolation in patients with chronic atrial fibrillation undergoing valvular operations.

Electrocardiographic characteristics of atrioventricular block induced by tilt testing.

PubMed

Zyśko, Dorota; Gajek, Jacek; Koźluk, Edward; Mazurek, Walentyna

2009-02-01

The electrocardiographic (ECG) characteristics of atrioventricular (AV) block during reflex syncope may be unique due to the presence of hypervagotonia. The aim of the present study was to define the ECG characteristics of the AV block induced by neurocardiogenic reflex provoked by tilt testing (TT). A series of 31 patients with presumed vasovagal syncope and AV block provoked by TT was studied. The duration of PP and PR interval, AV block grade and type, concomitant arrhythmias, and timing of the AV block occurrence were assessed. The AV block occurred at TT termination in 26 patients, in the recovery in 4 patients, and in both periods in 1 patient. Atrioventricular block was preceded by sinus slowing, and sinus rhythm during AV block was slow and instable. Mobitz I, 2:1 second-degree AV block, and advanced second-degree AV block were recognized in 35.5, 48.4, and 67.8% of patients, respectively. Third-degree AV block was diagnosed in 41.9% of patients. Twenty-one patients had at least two AV block forms. The most prevalent concomitant arrhythmia was junctional escape rhythm (61.3%). (i) The occurrence of the AV block during neurocardiogenic reaction induced by TT is always preceded by sinus rhythm slowing and usually by PR interval prolongation. (ii) The AV block provoked by TT usually occurs at TT termination, but may occur even in the recovery period in a supine position. Sometimes the AV block may be present both at TT termination and during the recovery period.

Simulation of Cardiac Arrhythmias Using a 2D Heterogeneous Whole Heart Model

PubMed Central

Balakrishnan, Minimol; Chakravarthy, V. Srinivasa; Guhathakurta, Soma

2015-01-01

Simulation studies of cardiac arrhythmias at the whole heart level with electrocardiogram (ECG) gives an understanding of how the underlying cell and tissue level changes manifest as rhythm disturbances in the ECG. We present a 2D whole heart model (WHM2D) which can accommodate variations at the cellular level and can generate the ECG waveform. It is shown that, by varying cellular-level parameters like the gap junction conductance (GJC), excitability, action potential duration (APD) and frequency of oscillations of the auto-rhythmic cell in WHM2D a large variety of cardiac arrhythmias can be generated including sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus pause, junctional rhythm, Wolf Parkinson White syndrome and all types of AV conduction blocks. WHM2D includes key components of the electrical conduction system of the heart like the SA (Sino atrial) node cells, fast conducting intranodal pathways, slow conducting atriovenctricular (AV) node, bundle of His cells, Purkinje network, atrial, and ventricular myocardial cells. SA nodal cells, AV nodal cells, bundle of His cells, and Purkinje cells are represented by the Fitzhugh-Nagumo (FN) model which is a reduced model of the Hodgkin-Huxley neuron model. The atrial and ventricular myocardial cells are modeled by the Aliev-Panfilov (AP) two-variable model proposed for cardiac excitation. WHM2D can prove to be a valuable clinical tool for understanding cardiac arrhythmias. PMID:26733873

Atrial fibrillation.

PubMed

Medi, Caroline; Hankey, Graeme J; Freedman, Saul B

2007-02-19

The incidence and prevalence of atrial fibrillation are increasing because of both population ageing and an age-adjusted increase in incidence of atrial fibrillation. Deciding between a rate control or rhythm control approach depends on patient age and comorbidities, symptoms and haemodynamic consequences of the arrhythmia, but either approach is acceptable. Digoxin is no longer a first-line drug for rate control: beta-blockers and verapamil and diltiazem control heart rate better during exercise. Anti-arrhythmic drugs have only a 40%-60% success rate of maintaining sinus rhythm at 1 year, and have significant side effects. The selection of optimal antithrombotic prophylaxis depends on the patient's risk of ischaemic stroke and the benefits and risks of long-term warfarin versus aspirin, but is independent of rate or rhythm control strategy. Ischaemic stroke risk is best estimated with the CHADS2 score (Congestive heart failure, Hypertension, Age > or = 75 years, Diabetes, 1 point each; prior Stroke or transient ischaemic attack, 2 points). For patients with valvular atrial fibrillation or a CHADS(2) score > or = 2, anticoagulation with warfarin is recommended (INR 2-3, higher for mechanical valves) unless contraindicated or annual major bleeding risk > 3%. Aspirin or warfarin may be used when the CHADS(2) score = 1. Aspirin, 81-325 mg daily, is recommended in patients with a CHADS(2) score of 0 or if warfarin is contraindicated. Stroke rate is similar for paroxysmal, persistent, and permanent atrial fibrillation, and probably for atrial flutter.

Diagnostic accuracy of a smartphone electrocardiograph in dogs: Comparison with standard 6-lead electrocardiography.

PubMed

Vezzosi, T; Buralli, C; Marchesotti, F; Porporato, F; Tognetti, R; Zini, E; Domenech, O

2016-10-01

The diagnostic accuracy of a smartphone electrocardiograph (ECG) in evaluating heart rhythm and ECG measurements was evaluated in 166 dogs. A standard 6-lead ECG was acquired for 1 min in each dog. A smartphone ECG tracing was simultaneously recorded using a single-lead bipolar ECG recorder. All ECGs were reviewed by one blinded operator, who judged if tracings were acceptable for interpretation and assigned an electrocardiographic diagnosis. Agreement between smartphone and standard ECG in the interpretation of tracings was evaluated. Sensitivity and specificity for the detection of arrhythmia were calculated for the smartphone ECG. Smartphone ECG tracings were interpretable in 162/166 (97.6%) tracings. A perfect agreement between the smartphone and standard ECG was found in detecting bradycardia, tachycardia, ectopic beats and atrioventricular blocks. A very good agreement was found in detecting sinus rhythm versus non-sinus rhythm (100% sensitivity and 97.9% specificity). The smartphone ECG provided tracings that were adequate for analysis in most dogs, with an accurate assessment of heart rate, rhythm and common arrhythmias. The smartphone ECG represents an additional tool in the diagnosis of arrhythmias in dogs, but is not a substitute for a 6-lead ECG. Arrhythmias identified by the smartphone ECG should be followed up with a standard ECG before making clinical decisions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clinical and electrocardiographic presentations of transient trifascicular block in three cats.

PubMed

Oxford, Eva M; Giacomazzi, Flavia B; Moïse, N Sydney; Santilli, Roberto A

2018-06-01

This report describes transient trifascicular block in three cats presented with lethargy and inappetence, and elevated cardiac troponin I concentrations. The electrocardiogram (ECG) of cat 1 showed a sinus rhythm with pronounced first-degree atrioventricular (AV) block, right bundle branch block, and left anterior fascicular block. The ECG of cat 2 showed truncular left bundle branch block alternating with left anterior fascicular block coupled with prolonged PR intervals, second-degree heart block, and paroxysmal third-degree AV block. The ECG of cat 3 showed first-degree AV block with concomitant right bundle branch block. The diagnosis of trifascicular block was made when paroxysmal third-degree AV block was documented. All cats recovered with medical management within weeks. Each cat resumed a sinus rhythm. Elevated cardiac troponin I concentrations suggested myocarditis that improved. Copyright © 2018 Elsevier B.V. All rights reserved.

[The risk of direct current countershock].

PubMed

Gajek, J; Zyśko, D

2001-07-01

Direct current cardioversion (DCC) is a procedure commonly used to restore the sinus rhythm in patients with supraventricular and ventricular arrhythmias. Its safety, regarding the use of electric current, is still a matter of controversy and debate. The patients with atrial fibrillation/flutter, supraventricular or ventricular tachycardia represent a broad spectrum of clinical conditions and it is difficult to draw the conclusions. The high success rate of DCC in restoring the sinus rhythm, may be partly responsible for enhancing and revealing proarrhythmic properties of antiarrhythmic drugs. The deaths described as a complications of DCC were mainly due to the proarrhythmia and less common to the progression of the pathologic process. The embolic, arrhythmic and anesthetic complications of DCC can be prevented if the known recommendations of performing the DCC are followed. The authors review critically the literature data about the complications of the procedure and come to the conclusion of safety of DCC.

Ordinal pattern statistics for the assessment of heart rate variability

NASA Astrophysics Data System (ADS)

Graff, G.; Graff, B.; Kaczkowska, A.; Makowiec, D.; Amigó, J. M.; Piskorski, J.; Narkiewicz, K.; Guzik, P.

2013-06-01

The recognition of all main features of a healthy heart rhythm (the so-called sinus rhythm) is still one of the biggest challenges in contemporary cardiology. Recently the interesting physiological phenomenon of heart rate asymmetry has been observed. This phenomenon is related to unbalanced contributions of heart rate decelerations and accelerations to heart rate variability. In this paper we apply methods based on the concept of ordinal pattern to the analysis of electrocardiograms (inter-peak intervals) of healthy subjects in the supine position. This way we observe new regularities of the heart rhythm related to the distribution of ordinal patterns of lengths 3 and 4.

The influence of cardiac rhythm type and frequency on the prognosis of severe heart failure patients initially qualified for heart transplantation.

PubMed

Sobieszczańska-Małek, Małgorzata; Zieliński, Tomasz; Rywik, Tomasz; Piotrowska, Małgorzata; Religa, Grzegorz; Przybyłowski, Piotr; Rózański, Jacek; Korewicki, Jerzy

2010-01-01

Atrial fibrillation (AF) is the most common arrhythmia among patients (pts) with heart failure and has significant influence on survival. to assess prognosis of pts with refractory heart failure (HF) qualified for heart transplantation (HTX). 872 pts (107 W and 765 M) were qualified for HTX between Dec 2003 and Oct 2007. Patient's death or super urgent heart transplantation were considered the end point in Kaplan-Meier survival curves. 680 pts were on sinus rhythm (SR) and 192(22.0%) had atrial fibrillation (AF). During follow-up (1-1464 days, mean 550 days) 155 pts (17.7%) died, 17.65% with SR and 18.23% with AF (ns). EF - mean 21,6 (SR) and 21,8 (FA), NYHA 3,1 (SR), NTproBNP- mean 3635, 4 (SR) and 4349,4 (FA), Arronson - mean 7,8 (SR) and 7,7 (FA). There were no significant differences between groups. We analyzed influence of heart rate (Kaplan-Maier method) on survival. The pts were divided according to HR: gr.I <70/min, gr II 71-89/min, gr III >90/min. The shortest survival rate was noticed in group III. There was no difference in survival between group I and II. The prognosis for patients qualified for heart transplant does not depend on the type of the dominant cardiac rhythm (atrial fibrillation or sinus rhythm). The prognosis is significantly better for those patients whose basic, resting heart rate does not exceed 90 bpm regardless of the rhythm type.

[Coronary artery spasm immediately after the long-standing operation for cancer of the tongue].

PubMed

Hayashida, M; Matsushita, F; Suzuki, S; Misawa, K

1992-12-01

A 72-year-old male underwent radical operation for cancer of the tongue. Anesthesia was maintained with the combination of enflurane-N2O-vecuronium and cervical epidural block. Five minutes after the cessation of the longstanding operation, VT and circulatory collapse occurred. After administration of lidocaine and ephedrine, VPC and ST elevation were noted, followed by VT and Vf. Cardioversion successfully restored sinus rhythm with no ST change, suggesting an episode of coronary artery spasm. The possible inducing factors in this case were hypotension and acute imbalance in autonomic nervous systems caused by hypovolemia, hypothermia, insufficient anesthetic depth, loss of surgical stress, neostigmine and epidural block. The authors reviewed case reports on coronary spasm, especially looking for possible inducing factors of coronary artery spasm during anesthesia.

Cost-effectiveness of cardioversion and antiarrhythmic therapy in nonvalvular atrial fibrillation.

PubMed

Catherwood, E; Fitzpatrick, W D; Greenberg, M L; Holzberger, P T; Malenka, D J; Gerling, B R; Birkmeyer, J D

1999-04-20

Physicians managing patients with nonvalvular atrial fibrillation must consider the risks, benefits, and costs of treatments designed to restore and maintain sinus rhythm compared with those of rate control with antithrombotic prophylaxis. To compare the cost-effectiveness of cardioversion, with or without antiarrhythmic agents, with that of rate control plus warfarin or aspirin. A Markov decision-analytic model was designed to simulate long-term health and economic outcomes. Published literature and hospital accounting information. Hypothetical cohort of 70-year-old patients with different baseline risks for stroke. 3 months. Societal. Therapeutic strategies using different combinations of cardioversion alone, cardioversion plus amiodarone or quinidine therapy, and rate control with antithrombotic treatment. Expected costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness. Strategies involving cardioversion alone were more effective and less costly than those not involving this option. For patients at high risk for ischemic stroke (5.3% per year), cardioversion alone followed by repeated cardioversion plus amiodarone therapy on relapse was most cost-effective ($9300 per QALY) compared with cardioversion alone followed by warfarin therapy on relapse. This strategy was also preferred for the moderate-risk cohort (3.6% per year), but the benefit was more expensive ($18,900 per QALY). In the lowest-risk cohort (1.6% per year), cardioversion alone followed by aspirin therapy on relapse was optimal. The choice of optimal strategy and incremental cost-effectiveness was substantially influenced by the baseline risk for stroke, rate of stroke in sinus rhythm, efficacy of warfarin, and costs and utilities for long-term warfarin and amiodarone therapy. Cardioversion alone should be the initial management strategy for persistent nonvalvular atrial fibrillation. On relapse of arrhythmia, repeated cardioversion plus low-dose amiodarone is cost-effective for patients at moderate to high risk for ischemic stroke.

Late Results of Cox Maze III Procedure in Patients with Atrial Fibrillation Associated with Structural Heart Disease

PubMed Central

Gomes, Gustavo Gir; Gali, Wagner Luis; Sarabanda, Alvaro Valentim Lima; da Cunha, Claudio Ribeiro; Kessler, Iruena Moraes; Atik, Fernando Antibas

2017-01-01

Background Cox-Maze III procedure is one of the surgical techniques used in the surgical treatment of atrial fibrillation (AF). Objectives To determine late results of Cox-Maze III in terms of maintenance of sinus rhythm, and mortality and stroke rates. Methods Between January 2006 and January 2013, 93 patients were submitted to the cut-and-sew Cox-Maze III procedure in combination with structural heart disease repair. Heart rhythm was determined by 24-hour Holter monitoring. Procedural success rates were determined by longitudinal methods and recurrence predictors by multivariate Cox regression models. Results Thirteen patients that obtained hospital discharge alive were excluded due to lost follow-up. The remaining 80 patients were aged 49.9 ± 12 years and 47 (58.7%) of them were female. Involvement of mitral valve and rheumatic heart disease were found in 67 (83.7%) and 63 (78.7%) patients, respectively. Seventy patients (87.5%) had persistent or long-standing persistent AF. Mean follow-up with Holter monitoring was 27.5 months. There were no hospital deaths. Sinus rhythm maintenance rates were 88%, 85.1% and 80.6% at 6 months, 24 months and 36 months, respectively. Predictors of late recurrence of AF were female gender (HR 3.52; 95% CI 1.21-10.25; p = 0.02), coronary artery disease (HR 4.73 95% CI 1.37-16.36; p = 0.01) and greater left atrium diameter (HR 1.05; 95% CI 1.01-1.09; p = 0.02). Actuarial survival was 98.5% at 12, 24 and 48 months and actuarial freedom from stroke was 100%, 100% and 97.5% in the same time frames. Conclusions The Cox-Maze III procedure, in our experience, is efficacious for sinus rhythm maintenance, with very low late mortality and stroke rates. PMID:28678926

Atrial fibrillation induced and converted by domestic supply electric shock.

PubMed

Rao, Usha; Agarwal, Ajit

2012-11-01

We present a case of persistent atrial fibrillation induced by a low-voltage electric shock reverting back to sinus rhythm after a similar repeat shock. ©2011, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

A novel atrial volume reduction technique to enhance the Cox maze procedure: initial results.

PubMed

Marui, Akira; Nishina, Takeshi; Tambara, Keiichi; Saji, Yoshiaki; Shimamoto, Takeshi; Nishioka, Masahiko; Ikeda, Tadashi; Komeda, Masashi

2006-11-01

Large left atrial diameter is reported to be a predictor for recurrent atrial fibrillation after the Cox maze procedure, and left atrial diameter by itself influences the chance of sinus rhythm recovery, as well as maintenance of sinus rhythm. However, additional cut-and-sew procedures to decrease left atrial diameter extend operative time and can cause bleeding. Thus we developed a no-bleeding, faster, and therefore less invasive left atrial volume reduction technique to enhance the Cox maze procedure. The modified Cox maze III procedure with cryoablation or the left atrial maze procedure in association with mitral valve surgery was performed in 80 patients with atrial fibrillation and enlarged left atria (> or =60 mm). Among them, 44 patients had the concomitant volume reduction technique (VR group); continuous horizontal mattress sutures for left atrial plication were placed on the left atrial wall along the pulmonary vein isolation line. Cryoablation was applied to the suture line so that the plicated left atrium is anatomically and electrically isolated. Another 36 patients did not have the volume reduction technique (control group). The VR group had preoperative left atrial diameters similar to those of the control group (67.1 +/- 7.8 vs 64.5 +/- 6.7 mm) and a longer preoperative duration of atrial fibrillation (14.1 +/- 5.4 vs 9.5 +/- 5.1 years, P < .05) but had smaller postoperative left atrial diameters (47.6 +/- 6.3 vs 62.1 +/- 7.9 mm, P < .01). There were no differences in mean crossclamp/bypass time and chest tube drainage for 12 hours between the groups. Twelve months after surgical intervention, the sinus rhythm recovery rate of the VR group was better than that of the control group (90% vs 69%, P < .05). Even in patients with long-standing atrial fibrillation and an enlarged left atrium, maze procedures concomitant with the novel left atrial volume reduction technique improved the sinus rhythm recovery rate without increasing complications. Although further study with a larger number of patients and a longer follow-up period is needed, this safe and thus far potent technique that catheter-based ablation cannot copy might extend indication of the Cox maze procedure for patients with tough atrial fibrillation.

Impact of left atrial volume reduction concomitant with atrial fibrillation surgery on left atrial geometry and mechanical function.

PubMed

Marui, Akira; Saji, Yoshiaki; Nishina, Takeshi; Tadamura, Eiji; Kanao, Shotaro; Shimamoto, Takeshi; Sasahashi, Nozomu; Ikeda, Tadashi; Komeda, Masashi

2008-06-01

Left atrial geometry and mechanical functions exert a profound effect on left ventricular filling and overall cardiovascular performance. We sought to investigate the perioperative factors that influence left atrial geometry and mechanical functions after the Maze procedure in patients with refractory atrial fibrillation and left atrial enlargement. Seventy-four patients with atrial fibrillation and left atrial enlargement (diameter > or = 60 mm) underwent the Maze procedure in association with mitral valve surgery. The maximum left atrial volume and left atrial mechanical functions (booster pump, reservoir, and conduit function [%]) were calculated from the left atrial volume-cardiac cycle curves obtained by magnetic resonance imaging. A stepwise multiple regression analysis was performed to determine the independent variables that influenced the postoperative left atrial geometry and function. The multivariate analysis showed that left atrial reduction surgery concomitant with the Maze procedure and the postoperative maintenance of sinus rhythm were predominant independent variables for postoperative left atrial geometry and mechanical functions. Among the 58 patients who recovered sinus rhythm, the postoperative left atrial geometry and function were compared between patients with (VR group) and without (control group) left atrial volume reduction. At a mean follow-up period of 13.8 months, sinus rhythm recovery rate was better (85% vs 68%, P < .05) in the VR group and maximum left atrial volume was less (116 +/- 25 mL vs 287 +/- 73 mL, P < .001) than in the control group. The maximum left atrial volume reduced with time only in the VR group (reverse remodeling). Postoperative booster pump and reservoir function in the VR group were better than in the control group (25% +/- 6% vs 11% +/- 4% and 34% +/- 7% vs 16% +/- 4%, respectively, P < .001), whereas the conduit function in the VR group was lower than in the control group, indicating that the improvement of the booster pump and reservoir function compensated for the conduit function to left ventricular filling. Left atrial reduction concomitant with the Maze procedure helped restore both contraction (booster pump) and compliance (reservoir) of the left atrium and facilitated left atrial reverse remolding. Left atrial volume reduction and postoperative maintenance of sinus rhythm may be desirable in patients with refractory AF and left atrial enlargement.

Value of an automatic external defibrillator printout as a diagnostic tool after successful AED use on a child.

PubMed

van Sambeeck, S J; van Gent, R; Schroër, C; Halbertsma, F J J

2013-04-22

A 6-year-old girl without any medical history experienced a drowning incident for a duration of 2 min, according to witnesses. This was followed by cardiopulmonary resuscitation, during which the automatic external defibrillator (AED) detected a shockable rhythm and subsequently delivered a single electroshock. At the time of admission, her medical history was unclear, and as her chest had been wet, it was not clear if the AED had been capable of correctly analysing the rhythm. The AED printout, however, revealed ventricular fibrillation (VF), which proved to be a primary cardiac cause at the time of the incident. This case report confirms the assumption that the AED can adequately perform rhythm analysis on children and convert VF into sinus rhythm. Moreover, the AED printout can provide information about the rhythm that is necessary for the diagnosis of an underlying cardiac disease.

Role of sinoatrial node architecture in maintaining a balanced source-sink relationship and synchronous cardiac pacemaking

PubMed Central

Unudurthi, Sathya D.; Wolf, Roseanne M.; Hund, Thomas J.

2014-01-01

Normal heart rhythm (sinus rhythm) depends on regular activity of the sinoatrial node (SAN), a heterogeneous collection of specialized myocytes in the right atrium. SAN cells, in general, possess a unique electrophysiological profile that promotes spontaneous electrical activity (automaticity). However, while automaticity is required for normal pacemaking, it is not necessarily sufficient. Less appreciated is the importance of the elaborate structure of the SAN complex for proper pacemaker function. Here, we review the important structural features of the SAN with a focus on how these elements help manage a precarious balance between electrical charge generated by the SAN (“source”) and the charge needed to excite the surrounding atrial tissue (“sink”). We also discuss how compromised “source-sink” balance due, for example to fibrosis, may promote SAN dysfunction, characterized by slow and/or asynchronous pacemaker activity and even failure, in the setting of cardiovascular disease (e.g., heart failure, atrial fibrillation). Finally, we discuss implications of the “source-sink” balance in the SAN complex for cell and gene therapies aimed at creating a biological pacemaker as replacement or bridge to conventional electronic pacemakers. PMID:25505419

An Unexpected Cause of Bradycardia in a Patient with Bacterial Meningitis.

PubMed

Ioannou, Petros; Velegraki, Magdalini; Soundoulounaki, Stella; Gikas, Achilleas; Kofteridis, Diamantis P

2017-01-01

Sinus bradycardia which is a sinus rhythm with a resting heart rate of less than 60 bpm is caused by intrinsic cardiac disorders like sick sinus syndrome or inferior myocardial infarction, metabolic and environmental causes (such as hypothyroidism and electrolyte disorders), medications (such as beta-blockers and amiodarone), infection (such as myocarditis), increased intracranial pressure, and toxic exposure, while it can sometimes be a normal phenomenon, especially during sleep, in athletes, and during pregnancy. Symptomatic sinus bradycardia should warrant a thorough work-up in order to identify any reversible causes; otherwise, placement of a permanent pacemaker could be needed. We present the case of a patient who was admitted due to confusion and fever and was found to have pneumococcal meningitis and bacteremia, and during his hospital stay he developed symptomatic sinus bradycardia that was of intractable cause and persistent. Placement of a permanent pacemaker was chosen until the night staff of the hospital discovered by chance the neglected cause of his bradycardia.

[Evaluation of the principles of distribution of electrocardiographic R-R intervals for elaboration of methods of automated diagnosis of cardiac rhythm disorders].

PubMed

Tsukerman, B M; Finkel'shteĭn, I E

1987-07-01

A statistical analysis of prolonged ECG records has been carried out in patients with various heart rhythm and conductivity disorders. The distribution of absolute R-R duration values and relationships between adjacent intervals have been examined. A two-step algorithm has been constructed that excludes anomalous and "suspicious" intervals from a sample of consecutively recorded R-R intervals, until only the intervals between contractions of veritably sinus origin remain in the sample. The algorithm has been developed into a programme for microcomputer Electronica NC-80. It operates reliably even in cases of complex combined rhythm and conductivity disorders.

Electrocardiographic predictors of adverse cardiovascular events in suspected poisoning.

PubMed

Manini, Alex F; Nelson, Lewis S; Skolnick, Adam H; Slater, William; Hoffman, Robert S

2010-06-01

Poisoning is the second leading cause of injury-related fatality in the USA and the leading cause of cardiac arrest in victims under 40 years of age. The study objective was to define the electrocardiographic (ECG) predictors of adverse cardiovascular events (ACVE) complicating suspected acute poisoning (SAP). This was a case-control study in adults at three tertiary-care hospitals and one regional Poison Control Center. We compared 34 cases of SAP complicated by ACVE to 101 consecutive control patients with uncomplicated SAP. The initial ECG was analyzed for rhythm, intervals, QT dispersion, ischemia, and infarction. ECGs were interpreted by a cardiologist, blinded to study hypothesis and case data. Subjects were 48% male, with mean age 42 +/- 19 years. In addition to clinical suspicion of poisoning in 100% of patients, routine toxicology screens were positive in 77%, most commonly for benzodiazepines, opioids, and/or acetaminophen. Neither the ventricular rate, the QRS duration, nor the presence of infarction predicted the risk of ACVE. However, the rhythm, QTc, QT dispersion, and presence of ischemia correlated with the risk of ACVE. Independent predictors of ACVE based on multivariable logistic regression were prolonged QTc, any non-sinus rhythm, ventricular ectopy, and ischemia. Recursive partitioning analysis identified very low risk criteria (94.1% sensitivity, 96.2% NPV) and high risk criteria (95% specificity). Among patients with SAP, the presence of QTc prolongation, QT dispersion, ventricular ectopy, any non-sinus rhythm, and evidence of ischemia on the initial ECG are strongly associated with ACVE.

Metoprolol vs ivabradine in patients with mitral stenosis in sinus rhythm.

PubMed

Agrawal, Vikas; Kumar, Niraj; Lohiya, Balalji; Sihag, Bhupendra K; Prajapati, Rajpal; Singh, T B; Subramanian, Geetha

2016-10-15

Severe mitral stenosis is usually symptomatic and is treated by BMV or surgery, whereas mild to moderate mitral stenosis is usually asymptomatic or mildly symptomatic and managed medically. Patients in the later group may become symptomatic during episodes of exercise and increased heart rate. Beta-blockers are frequently used in patients with mitral stenosis to control the heart rate and alleviate exercise-related symptoms. The objective of our study was to investigate the comparative efficacy of ivabradine versus metoprolol in patients with mitral stenosis in sinus rhythm. We studied 97 patients of mitral stenosis in sinus rhythm presented with exertional symptoms. The effectiveness of Metoprolol was compared with ivabradine in alleviating these exertional symptoms in a randomized, open label non crossover study. We also assessed various stress ECG parameters, 24 hour Holter parameters and 2D Echo parameters to objectively compare the effects of ivabradine and metoprolol in these patients. Ivabradine and metoprolol both were effective in controlling exertional symptoms. Significant improvement in objective parameters like TMT (work capacity, baseline heart rate and maximal heart rate) and 2D echocardiography (right ventricular systolic pressure) are seen with both drugs. Ivabradine controls the exertional symptoms significantly more than metoprolol. On head to head comparison there was a significant benefit of working capacity and heart rate at maximal exercise in favour of ivabradine. Ivabradine should be strongly considered in medical management of mitral stenosis patients where beta blockers are contraindicated such as reactive airway disease. The cost of ivabradine is higher than metoprolol which might possess constraints as most of the rheumatic heat disease patients belong to low socio economic status. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

HRV strongly depends on breathing. Are we questioning the right suspect?

PubMed

Buchner, Teodor

2011-01-01

The fact that the heart rate variability (HRV) depends on breathing is well known. The HRV is an important phenomenon which reflects the functional state of the autonomous nervous system (ANS), although there are some doubts concerning the actual interpretation of spectral components of HRV and their postulated balance. The assessment of the functional state of the ANS is the task of paramount importance in risk stratification of cardiological patients. HRV is considered to depend mainly on the properties of the sinus node (SN), which achieves neurohumoral input from the ANS. Interestingly, there is growing evidence that the relation between the heart rate (HR) and breathing rate (BR) is really strong. The variety of breathing-related effects that are present in HRV is very rich, including respiratory sinus arrhythmia (RSA), cardiorespiratory synchronization and vivid heart rate response to breathing disorders. If the mean frequency of any of rhythms is changed, the other rhythm adjusts itself. This provokes the question on the actual source of the dynamics observed in the HRV. Is it possible that we observe mainly the dynamics of the respiratory rhythm which is just transduced by the heart effector? What might be the role of the intrinsic dynamics of this effector? Is the RSA a product of neural regulation or rather a by-product: what is its teleological role? In consequence: if we concentrate on the sinus node and its properties in order to understand the nature of the HRV - are we questioning the right suspect? The reasoning is supplied by suitable choice of literature and by the analysis of the computational model. Various consequences are discussed.

User-initialized active contour segmentation and golden-angle real-time cardiovascular magnetic resonance enable accurate assessment of LV function in patients with sinus rhythm and arrhythmias.

PubMed

Contijoch, Francisco; Witschey, Walter R T; Rogers, Kelly; Rears, Hannah; Hansen, Michael; Yushkevich, Paul; Gorman, Joseph; Gorman, Robert C; Han, Yuchi

2015-05-21

Data obtained during arrhythmia is retained in real-time cardiovascular magnetic resonance (rt-CMR), but there is limited and inconsistent evidence to show that rt-CMR can accurately assess beat-to-beat variation in left ventricular (LV) function or during an arrhythmia. Multi-slice, short axis cine and real-time golden-angle radial CMR data was collected in 22 clinical patients (18 in sinus rhythm and 4 patients with arrhythmia). A user-initialized active contour segmentation (ACS) software was validated via comparison to manual segmentation on clinically accepted software. For each image in the 2D acquisitions, slice volume was calculated and global LV volumes were estimated via summation across the LV using multiple slices. Real-time imaging data was reconstructed using different image exposure times and frame rates to evaluate the effect of temporal resolution on measured function in each slice via ACS. Finally, global volumetric function of ectopic and non-ectopic beats was measured using ACS in patients with arrhythmias. ACS provides global LV volume measurements that are not significantly different from manual quantification of retrospectively gated cine images in sinus rhythm patients. With an exposure time of 95.2 ms and a frame rate of > 89 frames per second, golden-angle real-time imaging accurately captures hemodynamic function over a range of patient heart rates. In four patients with frequent ectopic contractions, initial quantification of the impact of ectopic beats on hemodynamic function was demonstrated. User-initialized active contours and golden-angle real-time radial CMR can be used to determine time-varying LV function in patients. These methods will be very useful for the assessment of LV function in patients with frequent arrhythmias.

Brain 'Embolism' Detected by Magnetic Resonance Imaging During Percutaneous Mitral Balloon Commissurotomy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocha, Paulo; Qanadli, Salah D.; Strumza, Pierre

1999-05-15

Purpose: The common finding of thrombi between the bifoil balloons when they were extracted after mitral dilation prompted us to look for evidence of minor brain embolisms using the sensitive technique of BMRI (brain magnetic resonance T2-weighted imaging). Methods: BMRI was performed within 48 hr before and after a percutaneous mitral balloon commissurotomy (PMBC) in each of the 63 patients in this study. Results: There was evidence (hyperintensity foci: HI) of a previous asymptomatic brain embolism in 38 of 63 patients before PMBC and a new HI appeared in 18 of 63 patients after the procedure. New HI signals weremore » found exclusively in the white matter in 8 of 18 patients and in only 3 of 18 were HI signs larger than 1 cm. One patient, with an HI signal >1 cm in the thalamus and another <1 cm in the brain stem, presented diplopia accompanied by other minor clinical signs. The differences in HI rate among four subgroups (1, older vs younger than 43 years; 2, sinus rhythm vs atrial fibrillation; 3, echo score <8 vs >8; 4, patients from western countries vs the others) were not statistically significant, probably because the number of patients in each subgroup was low. Patients in atrial fibrillation had slightly more (not significant) HI before PMBC (15/20, 75%) than patients in sinus rhythm (23/43, 53%), but after PMBC their HI frequencies were similar (atrial fibrillation: 5/20, 25%; sinus rhythm: 13/43, 30%). Conclusion: Brain microembolism is frequent during PMBC, but is often anatomically limited and free from clinical signs in most cases. Brain embolism seems to be related mainly to the procedure itself and not the features of the patient.« less

Lidocaine bolus may facilitate computed tomographic coronary angiography in patients with frequent premature ventricular contractions

PubMed Central

Jastrzębski, Jan; Kępka, Cezary; Kruk, Mariusz; Demkow, Marcin; Kalińczuk, Łukasz; Wolny, Rafał; Ciszewski, Michał; Michałowska, Ilona; Witkowski, Adam

2013-01-01

Introduction Heart rate irregularities are the major limitations of computed tomographic coronary angiography (CTCA) due to severe motion artifacts. Aim To evaluate the safety and efficacy of a lidocaine intravenous bolus in preserving good image quality by the transient suppression of premature ventricular contractions (PVC) during the CTCA scan. Material and methods The study group comprised 67 consecutive patients with sinus rhythm and numerous PVC scheduled for CTCA. Intravenous boluses of 25–50 mg lidocaine were given after calcium score assessment and immediately before CTCA. The control group comprised 67 patients with sinus rhythm without PVC matched according to the body mass index (BMI), age, sex, and calcium score. All coronary vessel segments were assessed for image quality and presence of significant stenosis. Results As compared with calcium score assessment, after administration of lidocaine and during the CTCA scan PVC were completely suppressed in 22 (40%), reduced in 10 (18%), unchanged in 18 (32%), and intensified in 5 (10%) patients. Overall, there were 32 (58%) patients with sinus rhythm during CTCA as compared with only 11 (20%) patients free from PVC during calcium score assessment (p < 0.001). Image quality in 871 coronary segments including both the study group and control patients was worse in patients with PVC (p < 0.0001). However, there was no statistically significant difference in the number of patients with at least one segment of non-diagnostic quality (6% vs. 12%, p = 0.36; respectively). Conclusions Single lidocaine bolus given prior to CTCA is safe, may temporarily eliminate or reduce the intensity of arrhythmia, and hence results in improved quality of CTCA in patients with numerous PVC. PMID:24570719

Left atrial pressure pattern without a-wave in sinus rhythm after cardioversion affects the outcomes after catheter ablation for atrial fibrillation.

PubMed

Kishima, Hideyuki; Mine, Takanao; Takahashi, Satoshi; Ashida, Kenki; Ishihara, Masaharu; Masuyama, Tohru

2018-04-24

The a-wave in left atrial pressure (LAP) is often not observed after cardioversion (CV). We hypothesized that repeated atrial fibrillation (AF) occurs in patients who do not show a-wave pattern after CV. We investigated the impact of "LAP pattern without a-wave" on the outcome after catheter ablation (CA) for AF. We studied 100 patients (64 males, age 66 ± 8 years, 42 with non-paroxysmal AF) who underwent CA for AF. Sustained- or induced-AF were terminated with internal CV, and LAP was measured during sinus rhythm (SR) after CV. LAP pattern without a-wave was defined as absence of a-wave (the "a-wave" was defined as a protruding part by 0.2 mmHg or more from the baseline) in LAP wave form. AF was terminated with CV in all patients. Recurrent AF was detected in 35/100 (35%) during the follow-up period (13.1 ± 7.8 month). Univariate analysis revealed higher prevalence of LAP pattern without a-wave (71 vs. 17%, P < 0.0001), larger left atrial volume, elevated E wave, and decreased deceleration time as significant variables. On multivariate analysis, LAP pattern without a-wave was only independently associated with recurrent AF (P = 0.0014, OR 9.865, 95% CI 2.327-54.861). Moreover, patients with LAP pattern without a-wave had a higher risk of recurrent AF than patients with a-wave (25/36 patients, 69 vs. 10/64 patients, 16%, log-rank P < 0.0001). Left atrial pressure pattern without a-wave in sinus rhythm after cardioversion could predict recurrence after catheter ablation for AF.

Dronedarone: drondarone, SR 33589, SR 33589B.

PubMed

2007-01-01

Dronedarone, a potassium channel antagonist, is chemically related to amio-darone. It is being developed by sanofi-aventis as a class III antiarrhythmic agent for the treatment of atrial fibrillation and atrial flutter in the US and Europe. Dronedarone has a favourable benefit/risk ratio, with the absence of any proarrhythmic effects. Sanofi merged with Synthélabo to form Sanofi-Synthélabo in 1999. In August 2004, Sanofi-Synthelabo merged with Aventis to form sanofi-aventis. The ATHENA trial is a multinational, randomised, double-blind trial evaluating the effects of dronedarone (400mg bid) compared with placebo, over a minimum 12-month follow-up period, in patients with atrial fibrillation or flutter. The trial is investigating the efficacy of dronedarone in preventing cardiovascular hospitalisations or death from any cause. Enrolment was extended to 4300 patients in order to attain the planned rate of adverse events; patient recruitment is ongoing.Previously, sanofi-aventis completed two pivotal phase III trials in atrial fibrillation. The trials, EURIDIS (EURopean trial In atrial fibrillation or flutter patients for the maintenance of Sinus rhythm) and ADONIS (American-Australasian trial with DronedarONe In atrial fibrillation or flutter patients for the maintenance of Sinus rhythm), involved 1237 patients who were in sinus rhythm at the time of randomisation. Results showed dronedarone to have anti-arrhythmic effects and a favourable benefit/risk ratio, with the absence of any proarrhythmic effect.Another trial, ERATO (Efficacy and safety of dronedARone for The cOntrol of ventricular rate), took place in 35 centres across nine European countries assessing dronedarone in 174 patients with permanent atrial fibrillation. Dronedarone was in phase II trials in Japan for the treatment of atrial fibrillation; however, no recent developments have been reported.

Loss of atrial contractility is primary cause of atrial dilatation during first days of atrial fibrillation.

PubMed

Schotten, Ulrich; de Haan, Sunniva; Neuberger, Hans-Ruprecht; Eijsbouts, Sabine; Blaauw, Yuri; Tieleman, Robert; Allessie, Maurits

2004-11-01

Atrial fibrillation (AF) induces a progressive dilatation of the atria which in turn might promote the arrhythmia. The mechanism of atrial dilatation during AF is not known. To test the hypothesis that loss of atrial contractile function is a primary cause of atrial dilatation during the first days of AF, eight goats were chronically instrumented with epicardial electrodes, a pressure transducer in the right atrium, and piezoelectric crystals to measure right atrial diameter. AF was induced with the use of repetitive burst pacing. Atrial contractility was assessed during sinus rhythm, atrial pacing (160-, 300-, and 400-ms cycle length), and electrically induced AF. The compliance of the fibrillating right atrium was measured during unloading the atria with diuretics and loading with 1 liter of saline. All measurements were repeated after 6, 12, and 24 h of AF and then once a day during the first 5 days of AF. Recovery of the observed changes after spontaneous cardioversion was also studied. After 5 days of AF, atrial contractility during sinus rhythm or slow atrial pacing was greatly reduced. During rapid pacing (160 ms) or AF, the amplitude of the atrial pressure waves had declined to 20% of control. The compliance of the fibrillating atria increased twofold, whereas the right atrial pressure was unchanged. As a result, the mean right atrial diameter increased by approximately 12%. All changes were reversible within 3 days of sinus rhythm. We conclude that atrial dilatation during the first days of AF is due to an increase in atrial compliance caused by loss of atrial contractility during AF. Atrial compliance and size are restored when atrial contractility recovers after cardioversion of AF.

Standardization of some electrocardiographic parameters of captive leopard cats (Leopardus tigrinus).

PubMed

Oda, Sam Goldy Shoyama; Yamato, Ronaldo Jun; Fedullo, José Daniel Luzes; Leomil Neto, Moacir; Larsson, Maria Helena Matiko Akao

2009-09-01

Thirty-three captive leopard cats, Leopardus tigrinus, were anesthetized with xylazine (1-2 mg/kg) and ketamine (10 mg/kg), and electrocardiograph (ECG) tests were recorded in all leads with 1 cm = 1 mV sensibility and 25 mm/sec speed repeating DII lead at 50 mm/sec speed with the same sensibility. Results expressed by mean and standard deviation were: heart rate (HR) = 107 +/- 17 (bpm); P-wave = 0.048 +/- 0.072 (s) x 0.128 +/- 0.048 (mV); PR interval = 0.101 +/- 0.081 (s); QRS compound = 0.053 +/- 0.012 (s) x 1.446 +/- 0.602 (mV); QT interval = 0.231 +/- 0.028 (s); R-wave (CV6LL) = 1.574 +/- 0.527 (mV); R-wave (CV6LU) = 1.583 +/- 0.818 (mV); heart rhythm: normal sinus rhythm (15.2%), sinus rhythm with wandering pacemaker (WPM) (60.6%), sinus arrhythmia with WPM (24.2%); electric axis: between +30 degrees and +60 degrees (6.1%), +60 (6.1%), between +60 degrees and +90 degrees (57.6%), +90 degrees (9%), between +90 degrees and +120 degrees (21.2%); ST segment: normal (75.7%), elevation (18.2%), depression (6.1%); T-wave polarity (DII): positive (100%); T-wave (V10): absent (6.1%), negative (63.6%), positive (18.2%), and with interference (12.1%). Through ECG data comparison with other species, unique features of Leopardus tigrinus' (leopard cat) ECG parameters were detected. Some of the study animals presented with an R-wave amplitude that was indicative of left ventricle overload according to patterns for normal domestic cats (Felis cati). Echocardiographic exams revealed normal heart cavities' function and morphology. The aim of this study was to establish some electrocardiographic parameters of captive L. tigrinus.

A Novel Application for the Detection of an Irregular Pulse using an iPhone 4S in Patients with Atrial Fibrillation

PubMed Central

McManus, David D.; Lee, Jinseok; Maitas, Oscar; Esa, Nada; Pidikiti, Rahul; Carlucci, Alex; Harrington, Josephine; Mick, Eric; Chon, Ki H.

2012-01-01

Background Atrial fibrillation (AF) is common and associated with adverse health outcomes. Timely detection of AF can be challenging using traditional diagnostic tools. Smartphone use is increasing and may provide an inexpensive and user-friendly means to diagnose AF. Objective To test the hypothesis that a smartphone-based application could detect an irregular pulse from AF. Methods 76 adults with persistent AF were consented for participation in our study. We obtained pulsatile time series recordings before and after cardioversion using an iPhone 4S camera. A novel smartphone application conducted real-time pulse analysis using 2 statistical methods [Root Mean Square of Successive RR Differences (RMSSD/mean); Shannon Entropy (ShE)]. We examined the sensitivity, specificity, and predictive accuracy of both algorithms using the 12-lead electrocardiogram as the gold standard. Results RMSDD/mean and ShE were higher in participants in AF compared with sinus rhythm. The 2 methods were inversely related to AF in regression models adjusting for key factors including heart rate and blood pressure (β coefficients per SD-increment in RMSDD/mean and ShE were −0.20 and −0.35; p<0.001). An algorithm combining the 2 statistical methods demonstrated excellent sensitivity (0.962), specificity (0.975), and accuracy (0.968) for beat-to-beat discrimination of an irregular pulse during AF from sinus rhythm. Conclusions In a prospectively recruited cohort of 76 participants undergoing cardioversion for AF, we found that a novel algorithm analyzing signals recorded using an iPhone 4S accurately distinguished pulse recordings during AF from sinus rhythm. Data are needed to explore the performance and acceptability of smartphone-based applications for AF detection. PMID:23220686

Targeting Stable Rotors to Treat Atrial Fibrillation.

PubMed

Narayan, Sanjiv M; Krummen, David E

2012-09-01

Therapy for atrial fibrillation (AF) remains suboptimal, in large part because its mechanisms are unclear. While pulmonary vein ectopy may trigger AF, it remains uncertain how AF, once triggered, is actually sustained. Recent discoveries show that human AF is maintained by a small number of rotors or focal sources. AF sources are widely distributed in patient-specific locations, often remote from pulmonary veins and in the right atrium and stable for prolonged periods of time. In a multicentre experience, brief targeted ablation at sources (focal impulse and rotor modulation [FIRM]) terminated AF predominantly to sinus rhythm prior to pulmonary vein isolation and eliminated AF on rigorous followup. This review summarises the evidence for stable rotors and focal sources of human AF and their clinical role as ablation targets to eliminate paroxysmal, persistent and long-standing persistent AF.

Spontaneous conversion of atrial fibrillation caused by severe hyperkalemia: A case report.

PubMed

Yan, Lihua; Jiang, Tingbo; Yang, Xiangjun; Xu, Mingzhu

2018-04-01

Hyperkalemia is a life-threatening electrolyte disturbance which could lead to arrhythmias and potentially death. An 82-year-old male patient who presented typical electrocardiographic indications of hyperkalemia, including the absence of P waves, prolongation of QRS complex, sinoventricular conduction, bradyarrhythmia and tall peaked T waves. He developed a rare self-defibrillation of atrial fibrillation to sinus rhythm due to hyperkalemia. Besides, he developed secondary thrombosis caused by abrupt termination of atrial fibrillation. This patient was diagnosed with hyperkalemia, hypertension, and AF. He was treated with an intravenous infusion of calcium gluconate, insulin and dextrose, an oral kayexalate, and emergency hemodialysis. The patient was managed effectively and discharged with stable status. Hyperkalemia could induce malignant arrhythmia with high mortality. Thus we suggested more attention be paid to monitoring electrolyte disorders and maintaining anticoagulation treatments to avoid thromboembolism.

Long-term outcomes following high intensity focused ultrasound ablation for atrial fibrillation.

PubMed

Davies, Edward J; Bazerbashi, Samer; Asopa, Sanjay; Haywood, Guy; Dalrymple-Hay, Malcolm

2014-01-01

The aim of this study is to assess the safety and efficacy of the Epicor high intensity focused ultrasound (St. Jude, Inc.®, Minneapolis, MN, USA) system using seven-day ambulatory electrocardiogram (ECG) monitoring over a two-year follow-up period. One hundred and ten patients undergoing ablation were included from a single center between January 2006 and December 2009. Rhythm was assessed using seven-day ambulatory ECG or permanent pacemaker interrogation. Seventeen patients were lost to follow-up, seven through death. Results were reported according to atrial fibrillation (AF) class preoperatively: paroxysmal, persistent, and long-standing persistent (LSP). Forty-nine percent of patients remained in sinus rhythm at greater than two years. The percentage of patients in sinus rhythm according to preoperative AF class were 81% (paroxysmal AF), 56% (persistent AF), and 18% (long-standing AF). The class of AF prior to surgery, left atrium size, and body mass index determined the long-term outcome. There were no procedure-related complications. We conclude that high intensity focused ultrasound ablation for atrial fibrillation using the Epicor system is safe and effective for surgical patients with paroxysmal AF. The persistent and LSP AF results suggest that alternative ablation strategies should be considered for these patients. © 2013 Wiley Periodicals, Inc.

Factors associated with the development of atrial fibrillation in patients with rheumatic mitral stenosis.

PubMed

Ozaydin, Mehmet; Turker, Yasin; Varol, Ercan; Alaca, Sule; Erdogan, Dogan; Yilmaz, Nigar; Dogan, Abdullah

2010-06-01

The aim of this study was to evaluate the factors associated with the development of atrial fibrillation (AF) in patients with rheumatic mitral stenosis (MS). A total of 146 consecutive patients with rheumatic MS were screened. They were accepted to be in AF group and sinus rhythm group according to their rhythm in the baseline ECG. After screening, 38 patients were excluded due to hyperthyroidism (n = 13), chronic obstructive pulmonary disease (n = 22), malignancy (n = 2) and rheumatoid arthritis (n = 1). Therefore, remaining 108 patients, 74 of whom in sinus rhythm (MS-SR) and 34 of whom in AF (MS-AF) constituted study population. Fourty age- and gender-matched patients constituted control group. Factors associated with development of AF in multivariable analysis included High sensitivity C reactive protein (P = 0.005; odds ratio, 3.44; 95% confidence interval, 1.44-8.22), N-terminal of brain natriuretic peptide precursor (P < 0.0001; odds ratio, 1.03; 95% confidence interval, 1.02-1.06) and left atrial diameter (P < 0.0001; odds ratio, 1.68; 95% confidence interval, 1.32-2.14). Present study suggests that High sensitivity C reactive protein, N-terminal of brain natriuretic peptide precursor and left atrial diameter are associated with development AF in patients with MS.

In-flight automated external defibrillator use and consultation patterns

PubMed Central

Brown, AM; Rittenberger, JC; Ammon, CM; Harrington, S; Guyette, FX

2010-01-01

Background Limited information exists about the in-flight use and outcomes associated with automatic external defibrillators (AED) on commercial airlines. Methods We collected self-reported cases of AED use to an airline consultation service from three US airlines between May 2004 and March 2009. We reviewed all available data files, related consult forms, and recordings. For each case, demographics, initial rhythm, shock delivery/success, survival to admission, and ground medical consultation use were obtained. Success was defined as the return of a perfusing rhythm. Initial rhythms were classified as: sinus, heart block, SVT, atrial fibrillation/flutter, asystole, PEA and VF/VT. Results There were a total of 169 AED applications with 40 cardiac arrests. The mean ages were 58 years (SD 15) and 63 years (SD 12) respectively; both populations were 64% male. AEDs were applied for monitoring in 129 (76%) cases with initial rhythms of: sinus 114 (88%); atrial fibrillation/flutter 7 (5%); complete heart block 4 (3%); and SVT 4 (3%). Presenting rhythms among the cardiac arrest population were: asystole 16 (40%); ventricular fibrillation/ventricular tachycardia 10 (25%); and PEA 14 (35%). Fourteen patients were defibrillated including nine of the 10 patients with initial VF/VT and five for the presence of VF/VT after resuscitation for initial PEA/asystole. Defibrillation was advised but not performed in the remaining case of initial VF/VT and no medical consult was obtained. All five successful defibrillations occurred in patients with initial VF/VT. There were 6 (15%; 95% CI 3–27%) survivors with 5 occurring after successful defibrillation for initial VF/VT and one with return of a perfusing rhythm after CPR for a junctional rhythm. Survival in those with VF/VT was 5/10 (50%; 95% CI 14–86%). Medications were delivered twice. The median time to first shock was 19 (IQR 12–24) seconds from AED application. Medical consultation was obtained in 56 (33%) of the 169 AED cases and 14 (35%) of the cardiac arrests. Conclusion AEDs resulted in 50% survival among those with VT/VF in-flight and 14% overall survival for cardiac arrest. Survival is poor among patients presenting with non-shockable rhythms. AEDs are used extensively for in-flight monitoring with significant rhythms identified. Ground medical consultation is sought in only one-third of AED uses and cardiac arrests. PMID:20128705

Inconsistent shock advisories for monomorphic VT and Torsade de Pointes--A prospective experimental study on AEDs and defibrillators.

PubMed

Fitzgerald, Abi; Johnson, Meshell; Hirsch, Jan; Rich, Mary-Ann; Fidler, Richard

2015-07-01

Cardiovascular disease and sudden cardiac arrest are the leading causes of death in the United States. Early defibrillation is key to successful resuscitation for patients who experience shockable rhythms during a cardiac arrest. It is therefore vital that the shock advisory of AEDs (automated external defibrillators) or defibrillators in AED mode be reliable and appropriate. The goal of this study was to better understand the performance of multiple lay-rescuer and hospital professional defibrillators in AED mode in their analysis of ventricular arrhythmias. The measurable objectives of this study sought to quantify: 1. No shock advisory for sinus rhythms at any rate. 2. Recognition and shock advisory for ventricular fibrillation (VF). 3. Recognition and shock advisory for monomorphic ventricular tachycardia (VT). 4. Recognition and shock advisory for Torsades de Pointes (TdP). This is a prospective evaluation of two AEDs and four semi-automatic, hospital professional defibrillators. This study represents post-marketing evaluation of FDA approved devices. Each defibrillator was connected to multiple rhythm simulators and presented with simulated ECG waveforms 20 consecutive times at various rates when possible. All four defibrillators and both AEDs tested consistently recognized normal sinus rhythm (NSR) from all rhythm sources, and did not recommend a shock for NSR at any rate (from 80 to 220 bpm). All four defibrillators and both AEDs recognized VF from all rhythm sources tested and recommended a shock 100% of the time. Variations were found in the shock advisory rates among defibrillators when testing simulated VT heart rates at or below 150 bpm. One AED tested did not consistently advise a shock for monomorphic VT or TdP at any tested rate. Lay-rescuer AEDs and professional hospital defibrillators tested in AED mode did not reliably recommend a shock for sustained monomorphic VT or TdP at certain rates, despite the fact that it is a critical component of the currently recommended treatment. These findings require further examination of the risk benefit analysis of shocking or not shocking rhythms such as TdP or pulseless VT. Published by Elsevier Ireland Ltd.

Adherence to optimal heart rate control in heart failure with reduced ejection fraction: insight from a survey of heart rate in heart failure in Sweden (HR-HF study).

PubMed

Fu, M; Ahrenmark, U; Berglund, S; Lindholm, C J; Lehto, A; Broberg, A Månsson; Tasevska-Dinevska, G; Wikstrom, G; Ågard, A; Andersson, B

2017-12-01

Despite that heart rate (HR) control is one of the guideline-recommended treatment goals for heart failure (HF) patients, implementation has been painstakingly slow. Therefore, it would be important to identify patients who have not yet achieved their target heart rates and assess possible underlying reasons as to why the target rates are not met. The survey of HR in patients with HF in Sweden (HR-HF survey) is an investigator-initiated, prospective, multicenter, observational longitudinal study designed to investigate the state of the art in the control of HR in HF and to explore potential underlying mechanisms for suboptimal HR control with focus on awareness of and adherence to guidelines for HR control among physicians who focus on the contributing role of beta-blockers (BBs). In 734 HF patients the mean HR was 68 ± 12 beats per minute (bpm) (37.2% of the patients had a HR >70 bpm). Patients with HF with reduced ejection fraction (HFrEF) (n = 425) had the highest HR (70 ± 13 bpm, with 42% >70 bpm), followed by HF with preserved ejection fraction and HF with mid-range ejection fraction. Atrial fibrillation, irrespective of HF type, had higher HR than sinus rhythm. A similar pattern was observed with BB treatment. Moreover, non-achievement of the recommended target HR (<70 bpm) in HFrEF and sinus rhythm was unrelated to age, sex, cardiovascular risk factors, cardiovascular diseases, and comorbidities, but was related to EF and the clinical decision of the physician. Approximately 50% of the physicians considered a HR of >70 bpm optimal and an equal number considered a HR of >70 bpm too high, but without recommending further action. Furthermore, suboptimal HR control cannot be attributed to the use of BBs because there was neither a difference in use of BBs nor an interaction with BBs for HR >70 bpm compared with HR <70 bpm. Suboptimal control of HR was noted in HFrEF with sinus rhythm, which appeared to be attributable to physician decision making rather than to the use of BBs. Therefore, our results underline the need for greater attention to HR control in patients with HFrEF and sinus rhythm and thus a potential for improved HF care.

Classification of cardiac rhythm using heart rate dynamical measures: validation in MIT-BIH databases.

PubMed

Carrara, Marta; Carozzi, Luca; Moss, Travis J; de Pasquale, Marco; Cerutti, Sergio; Lake, Douglas E; Moorman, J Randall; Ferrario, Manuela

2015-01-01

Identification of atrial fibrillation (AF) is a clinical imperative. Heartbeat interval time series are increasingly available from personal monitors, allowing new opportunity for AF diagnosis. Previously, we devised numerical algorithms for identification of normal sinus rhythm (NSR), AF, and SR with frequent ectopy using dynamical measures of heart rate. Here, we wished to validate them in the canonical MIT-BIH ECG databases. We tested algorithms on the NSR, AF and arrhythmia databases. When the databases were combined, the positive predictive value of the new algorithms exceeded 95% for NSR and AF, and was 40% for SR with ectopy. Further, dynamical measures did not distinguish atrial from ventricular ectopy. Inspection of individual 24hour records showed good correlation of observed and predicted rhythms. Heart rate dynamical measures are effective ingredients in numerical algorithms to classify cardiac rhythm from the heartbeat intervals time series alone. Copyright © 2015 Elsevier Inc. All rights reserved.

Idiopathic accelerated idioventricular rhythm or ventricular tachycardia originating from the right bundle branch: unusual type of ventricular arrhythmia.

PubMed

Chen, Minglong; Gu, Kai; Yang, Bing; Chen, Hongwu; Ju, Weizhu; Zhang, Fengxiang; Yang, Gang; Li, Mingfang; Lu, Xinzheng; Cao, Kejiang; Ouyang, Feifan

2014-12-01

Accelerated idioventricular rhythm (AIVR) or ventricular tachycardia (VT) originating from the right bundle branch (RBB) is rare and published clinical data on such arrhythmia are scarce. In this study, we will describe the clinical manifestations, diagnosis, and management of a cohort of patients with this novel arrhythmia. Eight patients (5 men; median age, 25 years) with RBB-AIVR/VT were consecutively enrolled in the study. Pharmacological testing, exercise treadmill testing, electrophysiological study, and catheter ablation were performed in the study patients, and ECG features were characterized. All RBB-AIVR/VTs were of typical left bundle-branch block morphology with atrioventricular dissociation. The arrhythmias, which demonstrated chronotropic variability, were often isorhythmic with sinus rhythm and were accelerated by physical exercise, stress, and intravenous isoprenaline infusion. The rate of RBB-AIVR/VT varied from 45 to 200 beats per minute. Two patients experienced syncope, and 3 had impaired left ventricular function. Metoprolol was proven to be the most effective drug to decelerate the arrhythmia rate and relieve symptoms. Electrophysiology study was performed in 5 patients and the earliest activation with a sharp RBB potential was localized in the mid or distal RBB area. Catheter ablation terminated the arrhythmia with subsequent RBB block morphology during sinus rhythm. During follow-up, patients' symptoms were controlled with normalization of left ventricular function either on metoprolol or by catheter ablation. RBB-AIVR/VT is an unusual type of ventricular arrhythmia. It can result in significant symptoms and depressed ventricular function and can be successfully treated with catheter ablation. © 2014 American Heart Association, Inc.

Two hearts synchronized each other with a DDD pacemaker.

PubMed

Brunacci, Michele; Valbusa, Alberto; Brunelli, Claudio; Bertero, Giovanni

2016-12-01

: We describe the case of a patient with dyspnea and heterotopic cardiac transplant, ventricular fibrillation from the native heart and sinus rhythm from the transplanted one. The two hearts were synchronized with a pacemaker. Electric external cardioversion and a different type of pacemaker stimulation were successfully performed, with improving symptoms.

Taser X26 discharges in swine: ventricular rhythm capture is dependent on discharge vector.

PubMed

Valentino, Daniel J; Walter, Robert J; Dennis, Andrew J; Margeta, Bosko; Starr, Frederic; Nagy, Kimberly K; Bokhari, Faran; Wiley, Dorion E; Joseph, Kimberly T; Roberts, Roxanne R

2008-12-01

Data from our previous studies indicate that Taser X26 stun devices can acutely alter cardiac function in swine. We hypothesized that most transcardiac discharge vectors would capture ventricular rhythm, but that other vectors, not traversing the heart, would fail to capture the ventricular rhythm. Using an Institutional Animal Care and Use Committee (IACUC) approved protocol, four Yorkshire pigs (25-36 kg) were anesthetized, paralyzed with succinylcholine (2 mg/kg), and then exposed to 10 second discharges from a police-issue Taser X26. For most discharges, the barbed darts were pushed manually into the skin to their full depth (12 mm) and were arranged in either transcardiac (such that a straight line connecting the darts would cross the region of the heart) or non-transcardiac vectors. A total of 11 different vectors and 22 discharge conditions were studied. For each vector, by simply rotating the cartridge 180-degrees in the gun, the primary current-emitting dart was changed and the direction of current flow during the discharge was reversed without physically moving the darts. Echocardiography and electrocardiograms (ECGs) were performed before, during, and after all discharges. p values < 0.05 were considered significant. ECGs were unreadable during the discharges because of electrical interference, but echocardiography images clearly demonstrated that ventricular rhythm was captured immediately in 52.5% (31 of 59) of the discharges on the ventral surface of the animal. In each of these cases, capture of the ventricular rhythm with rapid ventricular contractions consistent with ventricular tachycardia (VT) or flutter was seen throughout the discharge. A total of 27 discharges were administered with transcardiac vectors and ventricular capture occurred in 23 of these discharges (85.2% capture rate). A total of 32 non-transcardiac discharges were administered ventrally and capture was seen in only eight of these (25% capture rate). Ventricular fibrillation (VF) was seen with two vectors, both of which were transcardiac. In the remaining animals, VT occurred postdischarge until sinus rhythm was regained spontaneously. For most transcardiac vectors, Taser X26 caused immediate ventricular rhythm capture. This usually reverted spontaneously to sinus rhythm but potentially fatal VF was seen with two vectors. For some non-transcardiac vectors, capture was also seen but with a significantly (p < 0.0001) decreased incidence.

Epicardial Breakthrough Waves During Sinus Rhythm: Depiction of the Arrhythmogenic Substrate?

PubMed

Mouws, Elisabeth M J P; Lanters, Eva A H; Teuwen, Christophe P; van der Does, Lisette J M E; Kik, Charles; Knops, Paul; Bekkers, Jos A; Bogers, Ad J J C; de Groot, Natasja M S

2017-09-01

Epicardial breakthrough waves (EBW) during atrial fibrillation are important elements of the arrhythmogenic substrate and result from endo-epicardial asynchrony, which also occurs to some degree during sinus rhythm (SR). We examined the incidence and characteristics of EBW during SR and its possible value in the detection of the arrhythmogenic substrate associated with atrial fibrillation. Intraoperative epicardial mapping (interelectrode distances 2 mm) of the right atrium, Bachmann's bundle, the left atrioventricular groove, and the pulmonary vein area was performed during SR in 381 patients (289 male, 67±10 years) with ischemic or valvular heart disease. EBW were referred to as sinus node breakthrough waves if they were the earliest right atrial activated site. A total of 218 EBW and 57 sinus node breakthrough waves were observed in 168 patients (44%). EBW mostly occurred at right atrium (N=105, 48%) and left atrioventricular groove (N=67, 31%), followed by Bachmann's bundle (N=27, 12%) and pulmonary vein area (N=19, 9%; P <0.001). EBW occurred most often in ischemic heart disease patients (N=114, 49%) compared with (ischemic and) valvular heart disease patients (N=26, 17%; P <0.001). EBW electrograms most often consisted of double and fractionated potentials (N=137, 63%). In case of single potentials, an R wave was observed in 88% (N=71) of EBW, as opposed to 21% of sinus node breakthrough waves (N=5; P <0.001). Fractionated EBW potentials were more often observed at the right atrium and Bachmann's bundle ( P <0.001). During SR, EBW are present in over a third of patients, particularly in thicker parts of the atrial wall. Features of SR EBW indicate that muscular connections between endo- and epicardium underlie EBW and that a slight degree of endo-epicardial asynchrony required for EBW to occur is already present in some areas during SR. Hence, an anatomic substrate is present, which may enhance the occurrence of EBW during atrial fibrillation, thereby promoting atrial fibrillation persistence. © 2017 American Heart Association, Inc.

Catheter ablation of atrial fibrillation in patients with concomitant sinus bradycardia-Insights from the German Ablation Registry.

PubMed

Zylla, Maura M; Brachmann, Johannes; Lewalter, Thorsten; Hoffmann, Ellen; Kuck, Karl-Heinz; Andresen, Dietrich; Willems, Stephan; Hochadel, Matthias; Senges, Jochen; Katus, Hugo A; Thomas, Dierk

2016-01-01

This investigation addresses procedural characteristics of catheter ablation in patients with atrial fibrillation (AF) and sinus bradycardia. From the prospective, multi-center German Ablation Registry 1073 patients with sinus rhythm at the time of AF ablation were divided into two groups according to heart rate at start of procedure (A, <60 beats per minute (bpm), n=197; B, 60-99bpm, n=876). Acute procedural success was high (≥98%) and similar between groups. Procedure duration and energy application time were increased in group A (180min vs. 155min and 2561s vs. 1879s, respectively). Major complications were more frequent in group A (2.2% vs. 0.5%), and a greater proportion of these patients was discharged under antiarrhythmic medication (64% vs. 52%). Catheter ablation of AF with concomitant sinus bradycardia is associated with high procedural efficacy, longer procedure- and energy application durations, and a slightly elevated complication rate. Copyright © 2016 Elsevier Inc. All rights reserved.

Neonatal thyrotoxicosis with severe supraventricular tachycardia: case report and review of the literature.

PubMed

Abbasoğlu, Aslıhan; Ecevit, Ayşe; Tuğcu, Ali Ulaş; Erdoğan, Lkay; Kınık, Sibel Tulgar; Tarcan, Aylin

2015-03-01

Neonatal thyrotoxicosis is a rare condition caused by the transplacental passage of thyroid stimulating immunoglobulins from mothers with Graves' disease. We report a case of neonatal thyrotoxicosis with concurrent supraventricular tachycardia (SVT). The female infant, who was born by section due to breech delivery and meconium in the amniotic fluid at 36 weeks of gestation, presented with tachycardia on day 7. Her heart rate was between 260 and 300 beats/min, and an electrocardiogram revealed ongoing SVT. Sotalol was effective after two cardioversions in maintaining sinus rhythm. Thyroid function studies revealed hyperthyroidism in the infant, and her mother was found to have Graves' disease. Since symptoms and signs can vary, especially in preterm infants with neonatal hyperthyroidism, we want to emphasize the importance of prenatal care and follow-ups of Graves' disease associated pregnancies and management of newborns after birth.

Unusual presentation of total anomalous systemic venous connection.

PubMed

Vaidyanathan, Swaminathan; Kothandam, Sivakumar; Kumar, Rajesh; Pradhan, Priya M; Agarwal, Ravi

2017-07-01

A 9-year-old girl who presented with dyspnea on exertion was diagnosed with total anomalous systemic venous connection to the left atrium (both venae cavae), no left superior vena cava, and a moderate-sized atrial septal defect with severe pulmonary arterial hypertension and ectopic atrial rhythm. She underwent septation of the common atrium using autologous pericardium, thereby rerouting the superior vena cava, inferior vena cava, and coronary sinus to the right atrium. Her postoperative course was uneventful. This case is reported for its rarity of presentation with severe pulmonary arterial hypertension and ectopic atrial rhythm.

Sinus bradycardia during hypothermia in comatose survivors of out-of-hospital cardiac arrest - a new early marker of favorable outcome?

PubMed

Thomsen, Jakob Hartvig; Hassager, Christian; Bro-Jeppesen, John; Søholm, Helle; Nielsen, Niklas; Wanscher, Michael; Køber, Lars; Pehrson, Steen; Kjaergaard, Jesper

2015-04-01

Bradycardia is a common finding in patients undergoing therapeutic hypothermia (TH) following out-of-hospital cardiac arrest (OHCA), presumably as a normal physiological response to low body temperature. We hypothesized that a normal physiological response with sinus bradycardia (SB) indicates less neurological damage and therefore would be associated with lower mortality. We studied 234 consecutive comatose survivors of OHCA with presumed cardiac etiology and shockable primary rhythm, who underwent a full 24-h TH-protocol (33°C) at a tertiary heart center (years: 2004-2010). Primary endpoint was 180-day mortality; secondary endpoint was favorable neurological outcome (180-day cerebral performance category: 1-2). SB, defined as sinus rhythm <50 beats per minute during TH, was present in 115 (49%) patients. Baseline characteristics including sex, witnessed arrest, bystander cardiopulmonary resuscitation and time to return of spontaneous circulation were not different between SB- and no-SB patients. However, SB-patients were younger, 57±14 vs. 63±14 years, p<0.001 and less frequently had known heart failure (7% vs. 20%, p<0.01). Patients experiencing SB during the hypothermia phase of TH had a 17% 180-day mortality rate compared to 38% in no-SB patients (p<0.001), corresponding to a 180-day hazard ratio (HRadjusted=0.45 (0.23-0.88, p=0.02)) in the multivariable analysis. Similarly, SB during hypothermia was directly associated with lower odds of unfavorable neurological outcome (ORunadjusted=0.42 (0.23-0.75, p<0.01). Sinus bradycardia during therapeutic hypothermia is independently associated with a lower 180-day mortality rate and may thus be a novel, early marker of favorable outcome in comatose survivors of OHCA. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Nonthyroidal Illness Syndrome in Cardiac Illness Involves Elevated Concentrations of 3,5-Diiodothyronine and Correlates with Atrial Remodeling

PubMed Central

Dietrich, Johannes W.; Müller, Patrick; Schiedat, Fabian; Schlömicher, Markus; Strauch, Justus; Chatzitomaris, Apostolos; Klein, Harald H.; Mügge, Andreas; Köhrle, Josef; Rijntjes, Eddy; Lehmphul, Ina

2015-01-01

Background Although hyperthyroidism predisposes to atrial fibrillation, previous trials have suggested decreased triiodothyronine (T3) concentrations to be associated with postoperative atrial fibrillation (POAF). Therapy with thyroid hormones (TH), however, did not reduce the risk of POAF. This study reevaluates the relation between thyroid hormone status, atrial electromechanical function and POAF. Methods Thirty-nine patients with sinus rhythm and no history of atrial fibrillation or thyroid disease undergoing cardiac surgery were prospectively enrolled. Serum concentrations of thyrotropin, free (F) and total (T) thyroxine (T4) and T3, reverse (r)T3, 3-iodothyronamine (3-T1AM) and 3,5-diiodothyronine (3,5-T2) were measured preoperatively, complemented by evaluation of echocardiographic and electrophysiological parameters of cardiac function. Holter-ECG and telemetry were used to screen for POAF for 10 days following cardiac surgery. Results Seven of 17 patients who developed POAF demonstrated nonthyroidal illness syndrome (NTIS; defined as low T3 and/or low T4 syndrome), compared to 2 of 22 (p < 0.05) patients who maintained sinus rhythm. In patients with POAF, serum FT3 concentrations were significantly decreased, but still within their reference ranges. 3,5-T2 concentrations directly correlated with rT3 concentrations and inversely correlated with FT3 concentrations. Furthermore, 3,5-T2 concentrations were significantly elevated in patients with NTIS and in subjects who eventually developed POAF. In multivariable logistic regression FT3, 3,5-T2, total atrial conduction time, left atrial volume index and Fas ligand were independent predictors of POAF. Conclusion This study confirms reduced FT3 concentrations in patients with POAF and is the first to report on elevated 3,5-T2 concentrations in cardiac NTIS. The pathogenesis of NTIS therefore seems to involve more differentiated allostatic mechanisms. PMID:26279999

Early cardioversion of atrial fibrillation and atrial flutter guided by transoesophageal echocardiography: a single centre 8.5-year experience.

PubMed

Corrado, G; Santarone, M; Beretta, S; Tadeo, G; Tagliagambe, L M; Foglia-Manzillo, G; Spata, M; Miglierina, E; Acquati, F; Santarone, M

2000-04-01

To analyse the safety and impact on maintenance of sinus rhythm of transoesophageal echocardiographically guided early cardioversion associated with short-term anticoagulation in a large series of patients with atrial fibrillation and atrial flutter. Patients who were candidates for cardioversion were eligible for inclusion if they had atrial fibrillation or atrial flutter lasting longer than 2 days or of unknown duration. Patients received short-term anticoagulation with warfarin or heparin and underwent transthoracic echocardiography followed by transoesophageal echocardiography. Early cardioversion was performed if no thrombus was seen on the transoesophageal study. Warfarin was maintained for 1 month after cardioversion. In patients with atrial thrombi, cardioversion was deferred and prolonged anticoagulation was prescribed. The study population included 183 patients. One hundred and sixty nine patients without atrial thrombi underwent early cardioversion. Fourteen patients with atrial thrombi (7.6%) underwent a second transoesophageal echocardiogram after a median of 4 weeks of oral warfarin, and cardioversion was performed if clot regression was documented. No patient in our study population had a clinical thromboembolic event at 1 month follow-up (95% C.I. 0-0.016). The immediate success rate of cardioversion was better among patients with atrial fibrillation < 4 weeks duration compared with patients with atrial fibrillation of longer or of unknown duration: 96.6% vs 85%, respectively (P = 0.014). At 1 month follow-up, the percentage of arrhythmia relapses in patients with initially successful cardioversion was similar in the two groups (29% vs 26%, P = ns); thus the initial better outcome in patients with recent-onset arrhythmia was not lost. Transoesophageal echocardiography-guided early cardioversion in concert with short-term anticoagulation is safe. This approach permits abbreviation of the overall duration of atrial fibrillation and has a better impact on the maintenance of sinus rhythm for patients in whom the duration of atrial fibrillation is < 4 weeks.

Cardiac autotransplantation for the treatment of permanent atrial fibrillation combined with mitral valve disease.

PubMed

Troise, Giovanni; Brunelli, Federico; Cirillo, Marco; Amaducci, Andrea; Mhagna, Zen; Tomba, Margherita Dalla; Tasca, Giordano; Quaini, Eugenio

2003-01-01

The results of current surgical options for the treatment of permanent atrial fibrillation associated with mitral valve surgery are widely different, particularly for extremely dilated left atria. The aim of this study is to assess the efficacy of cardiac autotransplantation in restoring a normal sinus rhythm via a consistent reduction in the left atrium volume associated with a complete isolation of the pulmonary veins. From April 2000 to April 2002, 28 patients (men/women, 5/23) underwent cardiac autotransplantation for the treatment of mitral disease and concomitant permanent atrial fibrillation (>1 year). A modified surgical technique derived from bicaval heart transplantation procedures maintained the connection of the right atrium with the inferior vena cava in all but 3 cases. In 2 patients, the mitral valve was repaired, and it was replaced in 26 patients. Associated procedures were 6 aortic valve replacements, 2 tricuspid valve annuloplasties, and 2 coronary revascularizations. No hospital deaths were recorded, but 1 patient died of pneumonia 3 months postoperatively. At a mean follow-up period of 17.2 +/- 6.7 months (range, 6-30 months), 24 patients (88.9%) were in sinus rhythm, and 3 (11.1%) were in atrial fibrillation. The Santa Cruz Score was 0 for 3 patients, 2 for 1 patient, and 4 for the remaining 23 patients (85.2%). The mean left atrial diameter decreased from 65.4 +/- 17.1 mm (range, 50-130 mm) before the operation to 48.4 +/- 5.6 mm (range, 37-78 mm) postoperatively (P <.001), and the mean left atrial volume decreased from 119 +/- 70.5 mL (range, 60-426 mL) to 69.1 +/- 35.1 mL (range, 31-226 mL) (P <.0001). Cardiac autotransplantation is a safe and effective surgical option for the treatment of permanent atrial fibrillation in patients with long-lasting mitral valve disease and severe enlargement of the left atrium.

[Electrophysiological findings and ablation strategies in patients with atrial tachyarrhythmias after left atrial circumferential ablation in the treatment of atrial fibrillation].

PubMed

Chen, Ming-long; Yang, Bing; Xu, Dong-jie; Zou, Jian-gang; Shan, Qi-jun; Chen, Chun; Chen, Hong-wu; Li, Wen-qi; Cao, Ke-jiang

2007-02-01

To report the electrophysiological findings and the ablation strategies in patients with atrial tachyarrhythmias (ATAs) or atrial fibrillation (AF) recurrence after left atrial circumferential ablation (LACA) in the treatment of AF. 91 patients with AF had LACA procedure from April 2004 to May 2006, 19 of which accepted the second ablation procedure due to ATAs or AF recurrence. In all the 19 patients [17 male, 2 female, age 25 - 65 (53 +/- 12) years], 11 presented with paroxysmal AF before the first ablation procedure, 2 with persistent AF and 6 with permanent AF. Pulmonary vein potentials (PVP) were investigated in both sides in all the patients. Delayed PVP was identified inside the left circular line in 5 patients, in the right in 1 and both in 2 during sinus rhythm. "Gap" conduction was found and successfully closed guided by circular mapping catheter. In 3 cases, irregular left atrial tachycardia was caused by fibrillation rhythm inside the left ring via decremental "gap" conduction. Reisolation was done successfully again guided by 3-D mapping and made the left atrium in sinus rhythm but the fibrillation rhythm was still inside the left ring. Pulmonary vein tachycardia with 1:1 conduction to the left atrium presented in one case and reisolation stopped the tachycardia. No PVP was discovered in both sides in 4 patients but other tachycardias could be induced, including two right atrial scar related tachycardias, two supraventricular tachycardias mediated by concealed accessory pathway, one cavo-tricuspid isthmus dependent atrial flutter and one focal atrial tachycardia near the coronary sinus ostium. All the tachycardias in these 4 patients were successfully ablated with the help of routine and 3-D mapping techniques. In the rest 3, which were in AF rhythm, LACA was successfully done again. After a mean follow-up of 4 - 26 (11.5 +/- 8.5) months, 16 patients were symptom free without anti-arrhythmic drug therapy; 1 of them had frequent palpitation attack with Holter recording of atrial premature contractions; 2 of them with permanent AF became paroxysmal in one, and still in AF in the other. Reconduction between the left atrium and the pulmonary veins is the dominant factor for post-LACA ATAs and AF recurrence. Other forms of atrial tachycardias or supraventricular tachycardias may coexist with AF or sometimes trigger AF. LACA can not sufficiently modify AF substrate in some permanent AF patients.

Parametric imaging of experimentally simulated Wolff-Parkinson-White syndrome conduction abnormalities in dogs: a concise communication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weismueller, P.H.; Henze, E.; Adam, W.E.

1986-01-01

In order to test the diagnostic potential of phase analysis of radionuclide ventriculography (RNV) for localizing accessory bundles in Wolff-Parkinson-White (WPW) syndrome, 24 experimental runs were performed in three open chest instrumented dogs. After a baseline study, WPW syndrome was simulated by stimulation at seven different sites around the base of the ventricles, and RNV's were obtained. Subsequent data processing including Fourier transformation allowed the localization of the site of the first inward motion of the ventricles by an isophasic wave display. In sinus rhythm, the septum contracted first. During ectopic premature ventricular stimulation by triggering the atrial signal, themore » phase scan was altered only when the stimulus was applied earlier than 20 ms before the expected QRS complex during sinus rhythm. During stimulation with fixed frequency, only the left lateral positions of the premature stimulation were detected by phase analysis with a sensitivity of 86%. Neither the antero- or posteroseptal nor the right ventricular premature contraction pattern could be exactly localized.« less

Predictors of cerebral microembolization during phased radiofrequency ablation of atrial fibrillation: role of the ongoing rhythm and the site of energy delivery.

PubMed

Nagy-Balo, Edina; Kiss, Alexandra; Condie, Catherine; Stewart, Mark; Edes, Istvan; Csanadi, Zoltan

2014-11-01

Pulmonary vein isolation with phased radiofrequency current and use of a pulmonary vein ablation catheter (PVAC) has recently been associated with a high incidence of clinically silent brain infarcts on diffusion-weighted magnetic resonance imaging, and a high microembolic signal (MES) count detected by transcranial Doppler. We investigated the potential effects of the ongoing rhythm and the target vein during energy delivery (ED) on MES generation during PVAC ablations. A total of 735 EDs during 48 PVAC ablations were analyzed. MES counts were recorded for each ED and time-stamped for correlation with the ongoing rhythm and the target vein for each ED. Significantly higher MES counts were observed during ablations of the left-sided as compared with the right-sided pulmonary veins (P = 0.0003). Similarly, higher MES counts were detected during EDs in atrial fibrillation as compared with sinus rhythm when the temperature was >56°C (P < 0.0001). The ongoing rhythm had no effect on the number of MESs at lower temperatures during ablation. Both the ongoing rhythm during ED and the site of ablation influence microembolus generation during PVAC ablation procedures. ©2014 Wiley Periodicals, Inc.

A CASE OF GRANISETRON ASSOCIATED INTRAOPERATIVE CARDIAC ARREST.

PubMed

Al Harbi, Mohammed; Al Rifai, Derar; Al Habeeb, Hassan; Wambi, Freddie; Geldhof, Georges; Dimitriou, Vassilios

2016-02-01

We report a case of intraoperative severe bradycardia that resulted in asystole and cardiac arrest shortly after (<2 min) intravenous granisetron 1mg for postoperative nausea and vomiting prophylaxis, that occurred in a female patient who underwent an elective total thyroidectomy. After two cycles of cardiopulmonary resuscitation and defibrillation, spontaneous circulation and sinus rhythm returned successfully. Postoperatively, the patient was diagnosed with a drug-induced long QT syndrome. At the time of the event, granisetron was the only medication administered. Furthermore, there was no reason to suspect electrolyte abnormalities. We explore the association of the onset of severe sinus bradycardia with the intravenous administration of granisetron.

Autophagy as a mechanism for myolysis of cardiomyocytes in mitral regurgitation.

PubMed

Chen, Mien-Cheng; Chang, Jen-Ping; Wang, Ya-Hui; Liu, Wen-Hao; Ho, Wan-Chun; Chang, Hsueh-Wen

2011-03-01

Myolysis of atrial cardiomyocytes occurs in patients with severe mitral and tricuspid regurgitation. This morphological remodelling may involve autophagy. This study comprised 20 patients (10 with long-standing persistent atrial fibrillation and 10 with sinus rhythm) with severe mitral and tricuspid regurgitation. Atrial appendageal tissues were obtained during surgery. The appearance of autophagosomes (LC3B) in myocytes can reflect autophagy induction. Complement 9 is used as a reliable marker of oncosis. In the fibrillating right atria, 68·4 ± 18·9% of total myocytes showed moderate-to-severe myolysis, while 64·2 ± 15·8% of total myocytes comprised these cells in right atrial myocardium with sinus rhythm. Immunohistochemical study revealed LC3B-positive myocytes in 8·0% of myocytes without myolysis, 11·9% of myocytes with mild myolysis and 49·4% of myocytes with moderate-to-severe myolysis in right atrial myocardium with sinus rhythm (P < 0·0001). Similarly, in the fibrillating right atria, LC3B-positive myocytes were observed in 5·9% of myocytes without myolysis, 12·2% of myocytes with mild myolysis and 50·7% of myocytes with moderate-to-severe myolysis (P < 0·0001). Moreover, in the fibrillating left atria, LC3B-positive myocytes were observed in 4·9% of myocytes without myolysis, 12·6% of myocytes with mild myolysis and 52·0% of myocytes with moderate-to-severe myolysis (P < 0·0001). None of the atrial myocytes displayed intracellular deposition of complement 9. Induction of autophagy, but not oncosis, occurs in most cases of atrial cardiomyocytes with severe mitral and tricuspid regurgitation, even those without atrial fibrillation, and is closely associated with the development of myolysis in this disease. © 2010 The Authors. European Journal of Clinical Investigation © 2010 Stichting European Society for Clinical Investigation Journal Foundation.

Diagnostic accuracy and image quality of cardiac dual-source computed tomography in patients with arrhythmia.

PubMed

Tsiflikas, Ilias; Drosch, Tanja; Brodoefel, Harald; Thomas, Christoph; Reimann, Anja; Till, Alexander; Nittka, Daniel; Kopp, Andreas F; Schroeder, Stephen; Heuschmid, Martin; Burgstahler, Christof

2010-08-06

Cardiac multi-detector computed tomography (MDCT) permits accurate visualization of high-grade coronary artery stenosis. However, in patients with heart rate irregularities, MDCT was found to have limitations. Thus, the aim of the present study was to evaluate the diagnostic accuracy of a new dual-source computed tomography (DSCT) scanner generation with 83 ms temporal resolution in patients without stable sinus rhythm. 44 patients (31 men, mean age 67.5+/-9.2 years) without stable sinus rhythm and scheduled for invasive coronary angiography (ICA) because of suspected (n=17) or known coronary artery disease (CAD, n=27) were included in this study. All patients were examined with DSCT (Somatom Definition, Siemens). Besides assessment of total calcium score, all coronary segments were analyzed with regard to the presence of significant coronary artery lesions (>50%). The findings were compared to ICA in a blinded fashion. During CT examination, heart rhythm was as follows: 25 patients (57%) atrial fibrillation, 7 patients (16%) ventricular extrasystoles (two of them with atrial fibrillation), 4 patients (9%) supraventricular extrasystoles, 10 patients (23%) sinus arrhythmia (heart rate variability>10 bpm). Mean heart rate was 69+/-14 bpm, median 65 bpm. Mean Agatston score equivalent (ASE) was 762, ranging from 0 to 4949.7 ASE. Prevalence of CAD was 68% (30/44). 155 segments (27%) showed "step-ladder" artifacts and 28 segments (5%) could not be visualized by DSCT. Only 70 segments (12%) were completely imaged without any artifacts. Based on a coronary segment model, sensitivity was 73%, specificity 91%, positive predictive value 63%, and negative predictive value 94% for the detection of significant lesions (>or=50% diameter stenosis). Overall accuracy was 88%. In patients with heart rate irregularities, including patients with atrial fibrillation and a high prevalence of coronary artery disease, the diagnostic yield of dual-source computed tomography is still hampered due to a high number of segments with "step-ladder" artifacts. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Frailty syndrome in patients with heart rhythm disorders.

PubMed

Mlynarska, Agnieszka; Mlynarski, Rafal; Golba, Krzysztof S

2017-09-01

To assess the prevalence of frailty syndrome in patients with heart rhythm disorders that qualified for pacemaker implantation. The study included 171 patients (83 women, aged 73.9 ± 6.7 years) who qualified for pacemaker implantation as a result of sinus node dysfunction (81 patients) or atrio-ventricular blocks (AVB; 90 patients). A total of 60 patients (25 women, aged 72.40 ± 7.09 years) without heart rhythm disorders were included in the control group. Frailty syndrome was diagnosed using the Canadian Study of Health and Aging Clinical Frailty Scale test. Frailty syndrome was diagnosed in 25.15% of the patients, and pre-frailty in 36.84% of the patients. Frailty syndrome was diagnosed in 10% of the control group, and the average value of frailty was 3.35 ± 0.92. Frailty occurred significantly more often among patients with AVB (33.34%) compared with patients who were diagnosed with sinus node dysfunction (16.05%); P = 0.0081. The average score of frailty for sinus node dysfunction was 3.71 ± 0.89, and for AVB it was 4.14 ± 0.93; P = 0.0152. In the case of AVB, the women had a statistically more intense level of frailty of 4.54 ± 0.90 as compared with the men 3.87 ± 0.85; P = 0.0294. In the multiple logistic analysis, the presence of any arrhythmia was strongly associated with frailty syndrome (OR 2.1286, 95% CI 1.4594 - 3.1049; P = 0.0001). Frailty syndrome was diagnosed in one-quarter of patients with cardiac arrhythmias, whereas a further 40% were at a higher risk of frailty syndrome, and its occurrence was significantly higher if compared with the control group. Frailty occurred significantly more often among patients with atrio-ventricular blocks, especially in women. The results of the present research showed that there is a statistical association between frailty and arrhythmias. Geriatr Gerontol Int 2017; 17: 1313-1318. © 2016 Japan Geriatrics Society.

Upregulation of K(2P)3.1 K+ Current Causes Action Potential Shortening in Patients With Chronic Atrial Fibrillation.

PubMed

Schmidt, Constanze; Wiedmann, Felix; Voigt, Niels; Zhou, Xiao-Bo; Heijman, Jordi; Lang, Siegfried; Albert, Virginia; Kallenberger, Stefan; Ruhparwar, Arjang; Szabó, Gábor; Kallenbach, Klaus; Karck, Matthias; Borggrefe, Martin; Biliczki, Peter; Ehrlich, Joachim R; Baczkó, István; Lugenbiel, Patrick; Schweizer, Patrick A; Donner, Birgit C; Katus, Hugo A; Dobrev, Dobromir; Thomas, Dierk

2015-07-14

Antiarrhythmic management of atrial fibrillation (AF) remains a major clinical challenge. Mechanism-based approaches to AF therapy are sought to increase effectiveness and to provide individualized patient care. K(2P)3.1 (TASK-1 [tandem of P domains in a weak inward-rectifying K+ channel-related acid-sensitive K+ channel-1]) 2-pore-domain K+ (K(2P)) channels have been implicated in action potential regulation in animal models. However, their role in the pathophysiology and treatment of paroxysmal and chronic patients with AF is unknown. Right and left atrial tissue was obtained from patients with paroxysmal or chronic AF and from control subjects in sinus rhythm. Ion channel expression was analyzed by quantitative real-time polymerase chain reaction and Western blot. Membrane currents and action potentials were recorded using voltage- and current-clamp techniques. K(2P)3.1 subunits exhibited predominantly atrial expression, and atrial K(2P)3.1 transcript levels were highest among functional K(2P) channels. K(2P)3.1 mRNA and protein levels were increased in chronic AF. Enhancement of corresponding currents in the right atrium resulted in shortened action potential duration at 90% of repolarization (APD90) compared with patients in sinus rhythm. In contrast, K(2P)3.1 expression was not significantly affected in subjects with paroxysmal AF. Pharmacological K(2P)3.1 inhibition prolonged APD90 in atrial myocytes from patients with chronic AF to values observed among control subjects in sinus rhythm. Enhancement of atrium-selective K(2P)3.1 currents contributes to APD shortening in patients with chronic AF, and K(2P)3.1 channel inhibition reverses AF-related APD shortening. These results highlight the potential of K(2P)3.1 as a novel drug target for mechanism-based AF therapy. © 2015 American Heart Association, Inc.

Multistage electrotherapy delivered through chronically-implanted leads terminates atrial fibrillation with lower energy than a single biphasic shock.

PubMed

Janardhan, Ajit H; Gutbrod, Sarah R; Li, Wenwen; Lang, Di; Schuessler, Richard B; Efimov, Igor R

The goal of this study was to develop a low-energy, implantable device-based multistage electrotherapy (MSE) to terminate atrial fibrillation (AF). Previous attempts to perform cardioversion of AF by using an implantable device were limited by the pain caused by use of a high-energy single biphasic shock (BPS). Transvenous leads were implanted into the right atrium (RA), coronary sinus, and left pulmonary artery of 14 dogs. Self-sustaining AF was induced by 6 ± 2 weeks of high-rate RA pacing. Atrial defibrillation thresholds of standard versus experimental electrotherapies were measured in vivo and studied by using optical imaging in vitro. The mean AF cycle length (CL) in vivo was 112 ± 21 ms (534 beats/min). The impedances of the RA-left pulmonary artery and RA-coronary sinus shock vectors were similar (121 ± 11 Ω vs. 126 ± 9 Ω; p = 0.27). BPS required 1.48 ± 0.91 J (165 ± 34 V) to terminate AF. In contrast, MSE terminated AF with significantly less energy (0.16 ± 0.16 J; p < 0.001) and significantly lower peak voltage (31.1 ± 19.3 V; p < 0.001). In vitro optical imaging studies found that AF was maintained by localized foci originating from pulmonary vein-left atrium interfaces. MSE Stage 1 shocks temporarily disrupted localized foci; MSE Stage 2 entrainment shocks continued to silence the localized foci driving AF; and MSE Stage 3 pacing stimuli enabled consistent RA-left atrium activation until sinus rhythm was restored. Low-energy MSE significantly reduced the atrial defibrillation thresholds compared with BPS in a canine model of AF. MSE may enable painless, device-based AF therapy. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Multistage Electrotherapy Delivered Through Chronically-Implanted Leads Terminates Atrial Fibrillation With Lower Energy Than a Single Biphasic Shock

PubMed Central

Janardhan, Ajit H.; Gutbrod, Sarah R.; Li, Wenwen; Lang, Di; Schuessler, Richard B.; Efimov, Igor R.

2014-01-01

Objectives The goal of this study was to develop a low-energy, implantable device–based multistage electrotherapy (MSE) to terminate atrial fibrillation (AF). Background Previous attempts to perform cardioversion of AF by using an implantable device were limited by the pain caused by use of a high-energy single biphasic shock (BPS). Methods Transvenous leads were implanted into the right atrium (RA), coronary sinus, and left pulmonary artery of 14 dogs. Self-sustaining AF was induced by 6 ± 2 weeks of high-rate RA pacing. Atrial defibrillation thresholds of standard versus experimental electrotherapies were measured in vivo and studied by using optical imaging in vitro. Results The mean AF cycle length (CL) in vivo was 112 ± 21 ms (534 beats/min). The impedances of the RA–left pulmonary artery and RA–coronary sinus shock vectors were similar (121 ± 11 Ω vs. 126 ± 9 Ω; p = 0.27). BPS required 1.48 ± 0.91 J (165 ± 34 V) to terminate AF. In contrast, MSE terminated AF with significantly less energy (0.16 ± 0.16 J; p < 0.001) and significantly lower peak voltage (31.1 ± 19.3 V; p < 0.001). In vitro optical imaging studies found that AF was maintained by localized foci originating from pulmonary vein–left atrium interfaces. MSE Stage 1 shocks temporarily disrupted localized foci; MSE Stage 2 entrainment shocks continued to silence the localized foci driving AF; and MSE Stage 3 pacing stimuli enabled consistent RA–left atrium activation until sinus rhythm was restored. Conclusions Low-energy MSE significantly reduced the atrial defibrillation thresholds compared with BPS in a canine model of AF. MSE may enable painless, device-based AF therapy. PMID:24076284

Computer-based rhythm diagnosis and its possible influence on nonexpert electrocardiogram readers.

PubMed

Hakacova, Nina; Trägårdh-Johansson, Elin; Wagner, Galen S; Maynard, Charles; Pahlm, Olle

2012-01-01

Systems providing computer-based analysis of the resting electrocardiogram (ECG) seek to improve the quality of health care by providing accurate and timely automatic diagnosis of, for example, cardiac rhythm to clinicians. The accuracy of these diagnoses, however, remains questionable. We tested the hypothesis that (a) 2 independent automated ECG systems have better accuracy in rhythm diagnosis than nonexpert clinicians and (b) both systems provide correct diagnostic suggestions in a large percentage of cases where the diagnosis of nonexpert clinicians is incorrect. Five hundred ECGs were manually analyzed by 2 senior experts, 3 nonexpert clinicians, and automatically by 2 automated systems. The accuracy of the nonexpert rhythm statements was compared with the accuracy of each system statement. The proportion of rhythm statements when the clinician's diagnoses were incorrect and the systems instead provided correct diagnosis was assessed. A total of 420 sinus rhythms and 156 rhythm disturbances were recognized by expert reading. Significance of the difference in accuracy between nonexperts and systems was P = .45 for system A and P = .11 for system B. The percentage of correct automated diagnoses in cases when the clinician was incorrect was 28% ± 10% for system A and 25% ± 11% for system B (P = .09). The rhythm diagnoses of automated systems did not reach better average accuracy than those of nonexpert readings. The computer diagnosis of rhythm can be incorrect in cases where the clinicians fail in reaching the correct ECG diagnosis. Copyright © 2012. Published by Elsevier Inc.

Percutaneous Injection of Lidocaine Within the Carotid Body Area in Carotid Artery Stenting: An 'Old-New' Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mourikis, Dimitrios; Chatoupis, Konstantinos, E-mail: kchatoupis@yahoo.g; Katsenis, Konstantinos

2008-07-15

Severe bradycardia is a common untoward effect during balloon angioplasty when performing carotid artery stenting. Therefore atropine injection even before dilatation and the presence of an anesthesiologist are advocated in all patients. In the surgical literature, injection of a local anesthetic agent into the carotid sinus before carotid endarterectomy was performed in an attempt to ameliorate perioperative hemodynamic instability. This study was undertaken to test the hypothesis that percutaneous infiltration of the carotid sinus with local anesthetic immediately before balloon dilatation reduces bradycardia and ameliorates the need for atropine injection or the presence of an anesthesiologist. Infiltration of the carotidmore » sinus with 5 ml of 1% lidocaine, 3 min before dilatation, was performed in 30 consecutive patients. No one exhibited any significant rhythm change that required atropine injection. The anesthesiologist did not face any hemodynamic instability during the carotid artery stenting procedure.« less

Contemporary management of traumatic fractures of the frontal sinus.

PubMed

Guy, W Marshall; Brissett, Anthony E

2013-10-01

This article discusses the classic and contemporary management strategies for treating frontal sinus fractures. The goals of management of frontal sinus fractures are to create a safe sinus by minimizing the likelihood of early and late complications while preserving the function of the sinus and maintaining the cosmetic appearance of the upper face. The assessment and classification of patients with frontal sinus injuries, their management, and the treatment of complications are reviewed. Copyright © 2013 Elsevier Inc. All rights reserved.

Systematic evaluation of a tissue-engineered bone for maxillary sinus augmentation in large animal canine model.

PubMed

Wang, Shaoyi; Zhang, Zhiyuan; Xia, Lunguo; Zhao, Jun; Sun, Xiaojuan; Zhang, Xiuli; Ye, Dongxia; Uludağ, Hasan; Jiang, Xinquan

2010-01-01

The objective of this study is to systematically evaluate the effects of a tissue-engineered bone complex for maxillary sinus augmentation in a canine model. Twelve sinus floor augmentation surgeries in 6 animals were performed bilaterally and randomly repaired with the following 3 groups of grafts: group A consisted of tissue-engineered osteoblasts/beta-TCP complex (n=4); group B consisted of beta-TCP alone (n=4); group C consisted of autogenous bone obtained from iliac crest as a positive control (n=4). All dogs had uneventful healings following the surgery. Sequential polychrome fluorescent labeling, maxillofacial CT, microhardness tests, as well as histological and histomorphometric analyses indicated that the tissue-engineered osteoblasts/beta-TCP complex dramatically promoted bone formation and mineralization and maximally maintained the height and volume of elevated maxillary sinus. By comparison, both control groups of beta-TCP or autologous iliac bone showed considerable resorption and replacement by fibrous or fatty tissue. We thus conclude that beta-TCP alone could barely maintain the height and volume of the elevated sinus floor, and that the transplantation of autogenous osteoblasts on beta-TCP could promote earlier bone formation and mineralization, maximally maintain height, volume and increase the compressive strength of augmented maxillary sinus. This tissue engineered bone complex might be a better alternative to autologous bone for the clinical edentulous maxillary sinus augmentation. Copyright (c) 2009 Elsevier Inc. All rights reserved.

In-flight automated external defibrillator use and consultation patterns.

PubMed

Brown, Aaron Michael; Rittenberger, Jon C; Ammon, Charles M; Harrington, Scott; Guyette, Francis X

2010-01-01

Limited information exists about the in-flight use and outcomes associated with automated external defibrillators (AEDs) on commercial airlines. To describe the characteristics and outcomes of AED use during in-flight emergencies including in-flight cardiac arrest and the associated ground medical consultation patterns. We collected cases of AED use that were self-reported to an airline consultation service from three U.S. airlines between May 2004 and March 2009. We reviewed all available data files, related consultation forms, and recordings. For each case, demographics, initial rhythm, shock delivery/success, survival to admission, and ground medical consultation use were obtained. Success was defined as the return of a perfusing rhythm. Initial rhythms were classified as sinus, heart block, supraventricular tachycardia (SVT), atrial fibrillation/flutter, asystole, pulseless electrical activity (PEA), and ventricular fibrillation (VF)/ventricular tachycardia (VT). There were a total of 169 AED applications with 40 cardiac arrests. The mean patient ages were 58 years (standard deviation [SD] 15) and 63 years (SD 12), respectively; both populations were 64% male. AEDs were applied for monitoring in 129 (76%) cases with the following initial rhythms: sinus, 114 (88%); atrial fibrillation/flutter, seven (5%); complete heart block, four (3%); and SVT, four (3%). Presenting rhythms among the cardiac arrest population were as follows: asystole, 16 (40%); VF/VT, 10 (25%); and PEA, 14 (35%). Fourteen patients were defibrillated, including nine of the 10 patients with initial VF/VT and five for the presence of VF/VT after resuscitation for initial PEA/asystole. Defibrillation was advised but not performed in the remaining case of initial VF/VT, and no medical consultation was obtained. All five successful defibrillations occurred in patients with initial VF/VT. There were six (15%; 95% confidence interval [CI] 3-27%) survivors, with five survivals occurring after successful defibrillation for initial VF/VT and one with return of a perfusing rhythm after cardiopulmonary resuscitation (CPR) for a junctional rhythm. Survival in those with VF/VT was five of 10 (50%; 95% CI 14-86%). Medications were delivered in two cases. The median time to first shock was 19 seconds (interquartile range [IQR] 12-24 seconds) after AED application. Medical consultation was obtained in 42 (33%) of the 129 AED monitoring cases and 14 (35%) of the 40 cardiac arrest cases. Use of AEDs resulted in 50% survival among those with VF/VT in flight and 15% overall survival for cardiac arrest. Survival is poor among patients presenting with nonshockable rhythms. AEDs are used extensively for in-flight monitoring, with significant rhythms identified. Ground medical consultation is sought in only one-third of AED uses and cardiac arrests.

Recovery of atrial transport function after a maze procedure for atrial fibrillation in conversion of a failing Fontan circulation

PubMed Central

Bogers, A.J.J.C.; Kik, Ch.; de Jong, P.L.; Meijboom, F.J.

2008-01-01

Surgical ablation for atrial arrhythmias at conversion of atriopulmonary or ventriculopulmonary Fontan to a total cavopulmonary connection is feasible with recovery of both sinus rhythm and atrial transport function. Recovery of the patient’s physical condition may take up to a year. (Neth Heart J 2008;16:170-2.18566699) PMID:18566699

Clinically oriented device programming in bradycardia patients: part 2 (atrioventricular blocks and neurally mediated syncope). Proposals from AIAC (Italian Association of Arrhythmology and Cardiac Pacing).

PubMed

Palmisano, Pietro; Ziacchi, Matteo; Biffi, Mauro; Ricci, Renato P; Landolina, Maurizio; Zoni-Berisso, Massimo; Occhetta, Eraldo; Maglia, Giampiero; Botto, Gianluca; Padeletti, Luigi; Boriani, Giuseppe

2018-04-01

: The purpose of this two-part consensus document is to provide specific suggestions (based on an extensive literature review) on appropriate pacemaker setting in relation to patients' clinical features. In part 2, criteria for pacemaker choice and programming in atrioventricular blocks and neurally mediate syncope are proposed. The atrioventricular blocks can be paroxysmal or persistent, isolated or associated with sinus node disease. Neurally mediated syncope can be related to carotid sinus syndrome or cardioinhibitory vasovagal syncope. In sinus rhythm, with persistent atrioventricular block, we considered appropriate the activation of mode-switch algorithms, and algorithms for auto-adaptive management of the ventricular pacing output. If the atrioventricular block is paroxysmal, in addition to algorithms mentioned above, algorithms to maximize intrinsic atrioventricular conduction should be activated. When sinus node disease is associated with atrioventricular block, the activation of rate-responsive function in patients with chronotropic incompetence is appropriate. In permanent atrial fibrillation with atrioventricular block, algorithms for auto-adaptive management of the ventricular pacing output should be activated. If the atrioventricular block is persistent, the activation of rate-responsive function is appropriate. In carotid sinus syndrome, adequate rate hysteresis should be programmed. In vasovagal syncope, specialized sensing and pacing algorithms designed for reflex syncope prevention should be activated.

The normal electrocardiogram of four species of conscious raptors.

PubMed

Talavera, J; Guzmán, M J; del Palacio, M J Fernández; Albert, A P; Bayón, A

2008-02-01

The aim of this study was to describe normal ECG patterns and values in four species of conscious raptors (Eurasian kestrel, Griffon vulture, Little owl, and Eurasian Eagle owl). Electrocardiograms were carried out in 75 conscious birds belonging to four species of raptors. Lead II waveforms were analysed to determine amplitudes and durations of waves and intervals. Morphologic patterns of P-QRS-T deflections were analysed in the six limb leads. Rhythm, heart rate, mean electrical axis, presence of Ta wave, ST slurring, and P-on-T phenomenon were also studied. The influence of species, body weight and heart rate in electrocardiographic variables were statistically analysed (P < 0.05). Sinus rhythm was present in all tracings, showing sinus arrhythmia in four cases. Ta wave was present in six tracings and P-on-T phenomenon in four. ST segment could be identified in all tracings, being mainly high above baseline. Significant differences between species were found for all the electrocardiographic parameters. The heart rate and body weight were also found to be a significant influence in most parameters. This study provides electrocardiographic data for four species of raptors that can be used to establish comparisons for clinical purposes.

Prognosis of patients after open mitral commissurotomy. Actuarial analysis of late results in 100 patients.

PubMed

Housman, L B; Bonchek, L; Lambert, L; Grunkemeier, G; Starr, A

1977-05-01

The continuing controversy between proponents of open and closed commissurotomy might be clarified by analysis of late follow-up with modern actuarial techniques that provide a true perspective of patient risk. We have used open mitral commissurotomy exclusively for 15 years in 100 patients. There was one operative death from pancreatitis and one late death from cancer; the actuarially projected survival rate (+/- the standard error) at 10 years is 97 per cent (+/- 2). Thirteen patients had preoperative emboli, 6 of whom were in sinus rhythm and 7 in atrial fibrillation. Two patients had postoperative emboli, both in sinus rhythm. The actuarial chance of remaining free of embolism at 10 years is 97 per cent (+/- 2). Sixteen patients required reoperation on the mitral valve for functional deterioration. The remaining survivors were in Class I or II when last seen. The actuarial chance of not requiring a reoperation after 5 years is 91 per cent (+/- 4) and at 10 years, 38 per cent(+/- 16). Results in different centers are difficult to compare for many reasons, but imprecise statistical methods further obscure such comparisons. The use of actuarial techniques may help to define the role of open mitral commissurotomy.

Bachmann bundle pacing reduces atrial electromechanical delay in type 1 myotonic dystrophy patients.

PubMed

Russo, Vincenzo; Rago, Anna; Papa, Andrea Antonio; Arena, Giulia; Politano, Luisa; Nigro, Gerardo

2018-04-01

Atrial electromechanical delay (AEMD) is an echocardiographic parameter correlated with the onset of supraventricular arrhythmias in several clinical conditions. Inter-atrial septal pacing in the region of Bachmann's bundle (BB) has been shown to be safe and feasible in myotonic dystrophy type 1 (DM1) patients, with a low rate of sensing and pacing defects. The aim of this study was to assess the impact of temporary BB pacing compared with right atrial appendage (RAA) pacing on AEMD in DM1 patients undergoing pacemaker (PM) implantation for cardiac rhythm abnormalities. The study enrolled 70 consecutive DM1 patients undergoing PM implantation for cardiac rhythm abnormalities in accordance with the current guidelines. Seventy age- and sex-matched non-DM1 patients undergoing dual-chamber PM implantation for cardiac rhythm abnormalities were used as controls. The atrial pacing lead was temporarily positioned in the RAA and on the right side of the inter-atrial septum in the region of Bachmann's bundle. For each site (BB and RAA), temporary atrial pacing in the AAI mode was established at 10 beats per minute above the sinus rate and a detailed trans-thoracic echocardiogram with tissue Doppler (TDI) analysis was recorded after at least 10 min of atrial pacing to evaluate AEMD. Temporary RAA pacing did not show statistically significant differences in inter-AEMD (48.2 ± 17.8 vs 50.5 ± 16.5 ms; P = 0.8), intra-left AEMD (43.3 ± 15.5 vs 44.6 ± 15.8 ms; P = 0.1), or intra-right-AEMD (14.1 ± 4.2 vs 15.4 ± 5.8 ms; P = 0.9), in comparison with sinus rhythm. Temporary BB pacing determined a significantly lower inter-AEMD (36.1 ± 17.1 vs 50.5 ± 16.5 ms; P = 0.001) and intra-left AEMD (32.5 ± 15.2 vs 44.6 ± 15.8 ms; P = 0.001) values in comparison with temporary RAA pacing. No statistically significant difference was found in intra-right AEMD (12.2 ± 4.6 vs 15.4 ± 5.8 ms; P = 0.2). In the control group, neither temporary RAA pacing nor temporary BB pacing showed statistically significant differences in inter-AEMD, intra-left AEMD, or intra-right AEMD values in comparison with sinus rhythm. In DM1 patients undergoing dual-chamber PM implantation, atrial pacing in the Bachmann bundle region is associated with significantly lower echocardiographic indices of atrial electromechanical delay (inter-AEMD and intra-left AEMD) in comparison with RAA pacing.

Interatrial septum pacing decreases atrial dyssynchrony on strain rate imaging compared with right atrial appendage pacing.

PubMed

Yasuoka, Yoshinori; Abe, Haruhiko; Umekawa, Seiko; Katsuki, Keiko; Tanaka, Norio; Araki, Ryo; Imanaka, Takahiro; Matsutera, Ryo; Morisawa, Daisuke; Kitada, Hirokazu; Hattori, Susumu; Noda, Yoshiki; Adachi, Hidenori; Sasaki, Tatsuya; Miyatake, Kunio

2011-03-01

Interatrial septum pacing (IAS-P) decreases atrial conduction delay compared with right atrial appendage pacing (RAA-P). We evaluate the atrial contraction with strain rate of tissue Doppler imaging (TDI) during sinus activation or with IAS-P or RAA-P. Fifty-two patients with permanent pacemaker for sinus node disease were enrolled in the study. Twenty-three subjects were with IAS-P and 29 with RAA-P. The time from end-diastole to peak end-diastolic strain rate was measured and corrected with RR interval on electrocardiogram. It was defined as the time from end-diastole to peak end-diastolic strain rate (TSRc), and the balance between maximum and minimum TSRc at three sites (ΔTSRc) was compared during sinus activation and with pacing rhythm in each group. There were no significant differences observed in general characteristics and standard echocardiographic parameters except the duration of pacing P wave between the two groups. The duration was significantly shorter in the IAS-P group compared with the RAA-P group (95 ± 34 vs 138 ± 41; P = 0.001). TSRc was significantly different between sinus activation and pacing rhythm (36.3 ± 35.7 vs 61.6 ± 36.3; P = 0.003) in the RAA-P group, whereas no significant differences were observed in the IAS-P group (25.4 ± 12.1 vs 27.7 ± 14.7; NS). During the follow-up (mean 2.4 ± 0.7 years), the incidence of paroxysmal atrial fibrillation (AF) conversion to permanent AF was not significantly different between the two groups. IAS-P decreased the contraction delay on atrial TDI compared to RAA-P; however, it did not contribute to the reduction of AF incidence in the present study. ©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.

Heart rate variability to monitor performance in elite athletes: Criticalities and avoidable pitfalls.

PubMed

Lucini, Daniela; Marchetti, Ilaria; Spataro, Antonio; Malacarne, Mara; Benzi, Manuela; Tamorri, Stefano; Sala, Roberto; Pagani, Massimo

2017-08-01

Spectral analysis of Heart Rate Variability (HRV) is a simple, non-invasive technique that is widely used in sport to assess sympatho-vagal regulation of the heart. Its employment is increasing partly due to the rising usage of wearable devices. However data acquisition using these devices may be suboptimal because they cannot discriminate between sinus and non-sinus beats and do not record any data regarding respiratory frequency. This information is mandatory for a correct clinical interpretation. This study involved 974 elite athletes, all of them underwent a complete autonomic assessment, by way of Autoregressive HRV analysis. In 91 subjects (9% of the total population) we observed criticalities of either cardiac rhythm or respiration. Through perusal of one-lead ECG analysis we observed that 77 subjects had atrial or ventricular ectopy, i.e. conditions which impair stationarity and sinus rhythm. Running anyway autonomic nervous system analysis in this population, we observed that RR variance and raw values of LF and HF regions are significantly higher in arrhythmic subjects. In addition 14 subjects had slow (about 6 breath/min, 0.1Hz) respiration. This condition clouds the separation between LF from HF spectral regions of RR interval variability, respectively markers of the prevalent sympathetic and vagal modulation of SA node and of their synergistic interaction. Caution must be payed when assessing HRV with non-ECG wearable devices. Recording ECG signal and ensuring that respiratory rate is higher than 10 breath/min are both prerequisites for a more reliable analysis of HRV particularly in athletes. Copyright © 2017 Elsevier B.V. All rights reserved.

WITHDRAWN: Pharmacological cardioversion for atrial fibrillation and flutter.

PubMed

Cordina, John; Mead, Gillian E

2017-11-15

Atrial fibrillation is the commonest cardiac dysrhythmia. It is associated with significant morbidity and mortality. There are two approaches to the management of atrial fibrillation: controlling the ventricular rate or converting to sinus rhythm in the expectation that this would abolish its adverse effects. To assess the effects of pharmacological cardioversion of atrial fibrillation in adults on the annual risk of stroke, peripheral embolism, and mortality. We searched the Cochrane Controlled Trials Register (Issue 3, 2002), MEDLINE (2000 to 2002), EMBASE (1998 to 2002), CINAHL (1982 to 2002), Web of Science (1981 to 2002). We hand searched the following journals: Circulation (1997 to 2002), Heart (1997 to 2002), European Heart Journal (1997-2002), Journal of the American College of Cardiology (1997-2002) and selected abstracts published on the web site of the North American Society of Pacing and Electrophysiology (2001, 2002). Randomised controlled trials or controlled clinical trials of pharmacological cardioversion versus rate control in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and of any aetiology. One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed and the data were entered into RevMan. We identified two completed studies AFFIRM (n=4060) and PIAF (n=252). We found no difference in mortality between rhythm control and rate control relative risk 1.14 (95% confidence interval 1.00 to 1.31).Both studies show significantly higher rates of hospitalisation and adverse events in the rhythm control group and no difference in quality of life between the two treatment groups.In AFFIRM there was a similar incidence of ischaemic stroke, bleeding and systemic embolism in the two groups. Certain malignant dysrhythmias were significantly more likely to occur in the rhythm control group. There were similar scores of cognitive assessment.In PIAF, cardioverted patients enjoyed an improved exercise tolerance but there was no overall benefit in terms of symptom control or quality of life. There is no evidence that pharmacological cardioversion of atrial fibrillation to sinus rhythm is superior to rate control. Rhythm control is associated with more adverse effects and increased hospitalisation. It does not reduce the risk of stroke. The conclusions cannot be generalised to all people with atrial fibrillation. Most of the patients included in these studies were relatively older (>60 years) with significant cardiovascular risk factors.

Pharmacological cardioversion for atrial fibrillation and flutter.

PubMed

Cordina, J; Mead, G

2005-04-18

Atrial fibrillation is the commonest cardiac dysrhythmia. It is associated with significant morbidity and mortality. There are two approaches to the management of atrial fibrillation: controlling the ventricular rate or converting to sinus rhythm in the expectation that this would abolish its adverse effects. To assess the effects of pharmacological cardioversion of atrial fibrillation in adults on the annual risk of stroke, peripheral embolism, and mortality. We searched the Cochrane Controlled Trials Register (Issue 3, 2002), MEDLINE (2000 to 2002), EMBASE (1998 to 2002), CINAHL (1982 to 2002), Web of Science (1981 to 2002). We hand searched the following journals: Circulation (1997 to 2002), Heart (1997 to 2002), European Heart Journal (1997-2002), Journal of the American College of Cardiology (1997-2002) and selected abstracts published on the web site of the North American Society of Pacing and Electrophysiology (2001, 2002). Randomised controlled trials or controlled clinical trials of pharmacological cardioversion versus rate control in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and of any aetiology. One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed and the data were entered into RevMan. We identified two completed studies AFFIRM (n=4060) and PIAF (n=252). We found no difference in mortality between rhythm control and rate control relative risk 1.14 (95% confidence interval 1.00 to 1.31). Both studies show significantly higher rates of hospitalisation and adverse events in the rhythm control group and no difference in quality of life between the two treatment groups. In AFFIRM there was a similar incidence of ischaemic stroke, bleeding and systemic embolism in the two groups. Certain malignant dysrhythmias were significantly more likely to occur in the rhythm control group. There were similar scores of cognitive assessment. In PIAF, cardioverted patients enjoyed an improved exercise tolerance but there was no overall benefit in terms of symptom control or quality of life. There is no evidence that pharmacological cardioversion of atrial fibrillation to sinus rhythm is superior to rate control. Rhythm control is associated with more adverse effects and increased hospitalisation. It does not reduce the risk of stroke. The conclusions cannot be generalised to all people with atrial fibrillation. Most of the patients included in these studies were relatively older (>60 years) with significant cardiovascular risk factors.

Role of Rotors in the Ablative Therapy of Persistent Atrial Fibrillation

PubMed Central

Schricker, Amir A; Zaman, Junaid; Narayan, Sanjiv M

2015-01-01

Atrial fibrillation (AF) ablation is increasingly used to maintain sinus rhythm yet its results are sub-optimal, especially in patients with persistent AF or prior unsuccessful procedures. Attempts at improvement have often targeted substrates that sustain AF after it is triggered, yet those mechanisms are debated. Many studies now challenge the concept that AF is driven by self-sustaining disordered wavelets, showing instead that localised drivers (rotors) may drive disorder via a process known as fibrillatory conduction. Novel mapping using wide-area recordings, physiological filtering and phase analysis demonstrates rotors in human AF. Contact mapping with focal impulse and rotor modulation (FIRM) shows that localised ablation at sources can improve procedural success in many populations on long-term follow up and some newer approaches to rotor mapping are qualitatively similar. This review critically evaluates the data on rotor mapping and ablation, which advances our conceptual understanding of AF and holds the promise of substantially improving ablative outcomes in patients with persistent AF. PMID:26835100

Minimally Invasive Delivery of Hydrogel-Encapsulated Amiodarone to the Epicardium Reduces Atrial Fibrillation.

PubMed

Garcia, Jose R; Campbell, Peter F; Kumar, Gautam; Langberg, Jonathan J; Cesar, Liliana; Deppen, Juline N; Shin, Eric Y; Bhatia, Neal K; Wang, Lanfang; Xu, Kai; Schneider, Frank; Robinson, Brian; García, Andrés J; Levit, Rebecca D

2018-05-01

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Although treatment options for AF exist, many patients cannot be maintained in normal sinus rhythm. Amiodarone is an effective medication for AF but has limited clinical utility because of off-target tissue toxicity. Here, we use a pig model of AF to test the efficacy of an amiodarone-containing polyethylene glycol-based hydrogel. The gel is placed directly on the atrial epicardium through the pericardial space in a minimally invasive procedure using a specially designed catheter. Implantation of amiodarone-containing gel significantly reduced the duration of sustained AF at 21 and 28 days; inducibility of AF was reduced 14 and 21 days post-delivery. Off-target organ drug levels in the liver, lungs, thyroid, and fat were significantly reduced in animals treated with epicardial amiodarone gel compared with systemic controls in small-animal distribution studies. The pericardium is an underutilized therapeutic site and may be a new treatment strategy for AF and other cardiovascular diseases. © 2018 American Heart Association, Inc.

A Paradox-based data collection and management system for multi-center randomized clinical trials.

PubMed

Abdellatif, Mazen; Reda, Domenic J

2004-02-01

We have developed a Paradox-based data collection and management system for large-scale multi-site randomized clinical trials. The system runs under Windows operating system and integrates Symantec pcAnywhere32 telecommunications software for data transmission and remote control sessions, PKZIP utility for the compression/decompression of transmitted data, and Stat/Transfer for exporting the centralized Paradox database for analyses. We initially developed this system for VA Cooperative Study #399 'The Effect of Antiarrhythmic Therapy in Maintaining Stability of Sinus Rhythm in Atrial Fibrillation', which collects over 1000 variables on 706 patients at 20 sites. Patient intake for this 5-year study began in March of 1998. We have also developed an enhanced version of this system, which is being used in the NIH-funded 'Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT)' that collects over 1200 variables on 1588 patients at 13 sites. Patient intake for this 4-year study began in October of 2000.

Pacing-induced chronic atrial fibrillation impairs sinus node function in dogs. Electrophysiological remodeling.

PubMed

Elvan, A; Wylie, K; Zipes, D P

1996-12-01

We assessed the effects of pacing-induced chronic atrial fibrillation (AF) on sinus node function, intra-atrial conduction, and atrial refractoriness. In 15 mongrel dogs (20 to 30 kg), AV nodal block was produced by radiofrequency catheter ablation, and a ventricular-inhibited (VVI) pacemaker (Minix 8330, Medtronic) was implanted and programmed to pace at 80 pulses per minute. In 11 of these dogs, right atrial endocardial pacing leads were connected to a pulse generator (Itrel 7432, Medtronic) and set at a rate of 20 Hz to induce AF. Corrected sinus node recovery time, P-wave duration, 24-hour Holter ECG to assess AF duration, maximal heart rate in response to isoproterenol (10 micrograms/min), intrinsic heart rate after administration of atropine (0.04 mg/kg) and propranolol (0.1 mg/kg), and atrial effective refractory periods (ERPs) were obtained at baseline (EPS-1) and after 2 to 6 weeks (EPS-2) of VVI pacing alone (n = 4) or VVI pacing and rapid atrial pacing (n = 11). At EPS-2, corrected sinus node recovery time and P-wave duration were prolonged, maximal heart rate and intrinsic heart rate were decreased, atrial ERPs were shortened, and the duration of AF was increased significantly compared with EPS-1. These changes partially reversed toward baseline 1 week after conversion to sinus rhythm. Sinus node function and AF inducibility observed in the control dogs that underwent ventricular pacing alone (n = 4) did not change. Pacing-induced chronic AF induces sinus node dysfunction, prolongs intra-atrial conduction time, shortens atrial refractoriness, and perpetuates AF, changes that reverse gradually after termination of AF.

Intracellular Calcium Dynamics and the Acceleration of Sinus Rhythm by β-Adrenergic Stimulation

PubMed Central

Joung, Boyoung; Tang, Liang; Maruyama, Mitsunori; Han, Seongwook; Chen, Zhenhui; Stucky, Marcelle; Jones, Larry R.; Fishbein, Michael C.; Weiss, James N.; Chen, Peng-Sheng; Lin, Shien-Fong

2009-01-01

Background Recent evidence indicates that membrane voltage and Ca2+ clocks jointly regulate sinoatrial node (SAN) automaticity. Here we test the hypothesis that sinus rate acceleration by β-adrenergic stimulation involves synergistic interactions between these clock mechanisms. Methods and Results We simultaneously mapped intracellular calcium (Cai) and membrane potential (Vm) in 25 isolated canine right atrium (RA), using previously described criteria of the timing of late diastolic Cai elevation (LDCAE) relative to the action potential (AP) upstroke to detect the Ca2+ clock. Before isoproterenol, the earliest pacemaking site occurred in the inferior SAN, and LDCAE was observed in only 4/25 preparations. Isoproterenol (1 μmol/L) increased sinus rate and shifted pacemaking site to superior SAN, concomitant with the appearance of LDCAE preceding the AP upstroke by 98 ± 31 ms. Caffeine had similar effects, while SR Ca2+ depletion with ryanodine and thapsigargin prevented isoproterenol-induced LDCAE and blunted sinus rate acceleration. Cai transient relaxation time during ISO was shorter in superior SAN (124 ± 34 ms) than inferior SAN (138 ± 24 ms, p = 0.01) or RA (164 ± 33 ms, p = 0.001), and was associated with a lower SR Ca2+ ATPase pump to phospholamban protein ratio in SAN than in RA. If current blockade with ZD 7288 modestly blunted, but did not prevent LDCAE or sinus rate acceleration by isoproterenol. Conclusions Acceleration of the Ca2+ clock in the superior SAN plays an important role in sinus acceleration during β-adrenergic stimulation, interacting synergistically with the voltage clock to increase sinus rate. PMID:19188501

Clinical and electroencephalographic features of carotid sinus syncope induced by internal carotid artery angioplasty.

PubMed

Martinez-Fernandez, E; García, F Boza; Gonzalez-Marcos, J R; Peralta, A Gil; Garcia, A Gonzalez; Deya, A Mayol

2008-02-01

Carotid sinus syncope may occur acutely during internal carotid artery angioplasty (CA). We performed this study to investigate the clinical, electroencephalographic (EEG), and hemodynamic features of carotid sinus syncope induced by CA. Between 1992 and 2003, clinical, EEG, and cardiovascular monitoring was performed in 359 consecutive patients undergoing CA. Carotid sinus reaction (CSR) and syncope occurred in 62.7% and 18.6% of the procedures, respectively. CSR and syncopal spells were classified into cardioinhibitory, vasodepressor, and mixed type. Syncope occurred more frequently in patients with cardioinhibitory CSR (P < .001). The odds ratios for the risk of syncope in patients with cardioinhibitory CSR and vasodepressor/mixed CSR were 6.9 and 1.4, respectively. Sixty-one patients had cardioinhibitory syncope; 7 had the vasodepressor/mixed type. Thirteen spells were not related to cardiovascular disturbances. This last syncope subtype was significantly associated with brain hemodynamic disturbances, including a decrease in cerebral vasoreactivity (P = .04) and the absence of function of both communicating arteries (P = .03). Convulsive movements resembling supplementary sensorimotor seizures occurred in 79% of patients who experienced syncopal spells. EEG changes were more prominent in patients with cardioinhibitory syncope. Syncope occurs frequently in patients undergoing CA and can be misdiagnosed as seizures. The most frequent mechanism was a cardioinhibitory response. Cerebral hemodynamic disturbances may play a crucial role in the pathophysiology of syncope with normal sinus rhythm and normotension. Moreover, direct depression of the CNS following carotid sinus distension is likely to be involved.

Assessment of the effect of left atrial cryoablation enhanced by ganglionated plexi ablation in the treatment of atrial fibrillation in patients undergoing open heart surgery.

PubMed

Bárta, Jiří; Brát, Radim

2017-08-17

The aim of our study was to investigate, whether enhancement of left atrial cryoablation by ablation of the autonomic nervous system of left atrium leads to influencing the outcomes of surgical treatment of atrial fibrillation in patients with structural heart disease undergoing open-heart surgery. The observed patient file consisted of 100 patients, who have undergone a combined open-heart surgery at our department between July 2012 and December 2014. The patients were indicated for the surgical procedure due to structural heart disease, and suffered from paroxysmal, persistent, or long-standing persistent atrial fibrillation. In all cases, left atrial cryoablation was performed in the extent of isolation of pulmonary veins, box lesion, connecting lesion with mitral annulus, amputation of the left atrial appendage and connecting lesion of the appendage base with left pulmonary veins. Furthermore, 35 of the patients underwent mapping and radiofrequency ablation of ganglionated plexi, together with discision and ablation of the ligament of Marshall (Group GP). A control group was consisted of 65 patients without ganglionated plexi intervention (Group LA). The main primary outcome was establishment and duration of sinus rhythm in the course of one-year follow-up. Evaluation of the number of patients with a normal sinus rhythm in per cent has shown comparable values in both groups (Group GP - 93.75%, Group LA - 86.67%, p = 0.485); comparable results were also observed in patients with normal sinus rhythm without anti-arrhythmic treatment in the 12th month (Group GP - 50%, Group LA - 47%, p = 0.306). We have not observed any relation between the recurrence of atrial fibrillation and the presence of a mitral valve surgery, or between the presence of a mitral and tricuspid valves surgery and between the left atrial diameter > 50 mm. Enhancement of left atrial cryoablation by gangionated plexi ablation did not influence the outcomes of surgical ablation due to atrial fibrillation in our population in the course of 12-month follow-up. The study was approved retrospectively by the Ethics Committee of the University Hospital Ostrava ( reference number 867/2016).

Incidence and Predictors of Long-Term Adverse Outcomes in Patients with Rheumatic Mitral Stenosis in Sinus Rhythm.

PubMed

Nachom, Patsadee; Ratanasit, Nithima

2016-04-01

Rheumatic fever and rheumatic heart disease remain important health problems in developing countries. Mitral stenosis (MS) is the most common form of rheumatic heart disease. The aim of this study was to investigate incidence and echocardiographic predictors of long-term adverse outcomes in patients with rheumatic mitral stenosis in sinus rhythm. We retrospectively reviewed medical records of patients diagnosed with isolated rheumatic MS of any severity at Siriraj Hospital between 1996 and 2013. Demographic data, echocardiographic data, and long-term adverse outcomes were collected. Long-term adverse outcomes included all-cause mortality, hospitalization due to heart failure, new-onset atrial fibrillation, and/or embolic stroke during follow-up. One hundred eighty five patients (aged 41.9 ± 13.2 years, 81.1% female) were included during the median follow-up period of 12.6 years (95% CI: 11.2-14.0). MS was classified as mild, moderate, and severe in 8.6%, 2 7.6%, and 63.8% of patients, respectively. Average mitral valve score was 8.25 ± 1.5. Most patients (61.6%) underwent percutaneous balloon mitral valvulotomy. Incidence of long-term adverse outcome was 43.2% (95% CI: 36.0-50.7%) and included mortality in two patients (1.1%, 95% CI: 0.13-3.9%), hospitalization due to heart failure in 20 patients (10.8%, 95% CI: 6.7-16.2%), new-onset atrial fibrillation in 71 patients (38.4%, 95% CI: 31.3-45.8%), and embolic stroke in 14 patients (7.6%, 95% CI: 4.2-12.4%). Echocardiographic parameters associated with long-term adverse outcomes were left atrial dimension greater than 50 mm (HR 2.61, 95% CI: 1.08-6.30; p = 0.03) and left ventricular end-systolic dimension less than 28 mm (HR 3.06, 95% CI: 1.25-7.49; p = 0.01). Long-term adverse outcomes are common in patients with rheumatic MS in sinus rhythm. Long-term adverse outcomes were found to correlate with left atrial dimension and left ventricular end-systolic dimension.

Magnetophysiologic and echocardiographic comparison of blocked atrial bigeminy and 2:1 atrioventricular block in the fetus.

PubMed

Wiggins, Delonia L; Strasburger, Janette F; Gotteiner, Nina L; Cuneo, Bettina; Wakai, Ronald T

2013-08-01

Blocked atrial bigeminy (BAB) and second-degree atrioventricular block with 2:1 conduction block (2:1 AVB) both present as ventricular bradycardia and can be difficult to distinguish by echocardiography. Since the prognosis and clinical management of these rhythms are different, an accurate diagnosis is essential. To identify magnetic and mechanical heart rate and rhythm parameters that could reliably distinguish BAB from 2:1 AVB. A retrospective study of ten BAB and seven 2:1 AVB subjects was performed, using fMCG and pulsed Doppler ultrasound. Distinguishing BAB from 2:1 AVB by using fMCG was relatively straightforward because in BAB the ectopic P wave (P') occurred early, resulting in a bigeminal (short-long) atrial rhythm. The normalized coupling interval of the ectopic beat (PP' of the blocked beat to PP of the conducted beat) was 0.29 ± 0.03. In contrast, the echocardiographic assessment of inflow-outflow gave a normalized mechanical coupling interval (AA'/AA) near 0.5, which made it difficult to distinguish BAB from 2:1 AVB. Heart rate distinguished most subjects with BAB from those with 2:1 AVB (82 ± 5.7 beats/min vs 69 ± 4.2 beats/min), but was not a completely reliable indicator. In most subjects, BAB alternated with sinus rhythm or other rhythms, resulting in complex heart rate and rhythm patterns. Fetal BAB and 2:1 AV block can be difficult to distinguish using echocardiography because in many fetuses with BAB the mechanical rhythm does not accurately reflect the magnetic rhythm. fMCG provides a more reliable means of making a differential diagnosis. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

The role of the daily feeding rhythm in the regulation of the day/night rhythm in triglyceride secretion in rats.

PubMed

Su, Yan; Foppen, Ewout; Mansur Machado, Frederico Sander; Fliers, Eric; Kalsbeek, Andries

2018-02-15

Plasma triglyceride (TG) levels show a clear daily rhythm, however, thus far it is still unknown whether this rhythm results from a daily rhythm in TG production, TG uptake or both. Previous studies have shown that feeding activity affects plasma TG concentrations, but it is not clear how the daily rhythm in feeding activity affects plasma TG concentrations. In the present study, we measured plasma TG concentrations and TG secretion rates in rats at 6 Zeitgeber times to investigate whether plasma TG concentrations and TG secretion show a daily rhythm. We found that plasma TG concentrations and TG secretion show a significant day/night rhythm. Next, we removed the daily rhythm in feeding behavior by introducing a 6-meals-a-day (6M) feeding schedule to investigate whether the daily rhythm in feeding behavior is necessary to maintain the daily rhythm in TG secretion. We found that the day/night rhythm in TG secretion was abolished under 6M feeding conditions. Hepatic apolipoprotein B (ApoB) and microsomal TG transfer protein (Mttp), which are both involved in TG secretion, also lost their daily rhythmicity under 6M feeding conditions. Together, these results indicate that: (1) the daily rhythm in TG secretion contributes to the formation of a day/night rhythm in plasma TG levels and (2) a daily feeding rhythm is essential for maintaining the daily rhythm in TG secretion.

Pineal Photoreceptor Cells Are Required for Maintaining the Circadian Rhythms of Behavioral Visual Sensitivity in Zebrafish

PubMed Central

Li, Xinle; Montgomery, Jake; Cheng, Wesley; Noh, Jung Hyun; Hyde, David R.; Li, Lei

2012-01-01

In non-mammalian vertebrates, the pineal gland functions as the central pacemaker that regulates the circadian rhythms of animal behavior and physiology. We generated a transgenic zebrafish line [Tg(Gnat2:gal4-VP16/UAS:nfsB-mCherry)] in which the E. coli nitroreductase is expressed in pineal photoreceptor cells. In developing embryos and young adults, the transgene is expressed in both retinal and pineal photoreceptor cells. During aging, the expression of the transgene in retinal photoreceptor cells gradually diminishes. By 8 months of age, the Gnat2 promoter-driven nitroreductase is no longer expressed in retinal photoreceptor cells, but its expression in pineal photoreceptor cells persists. This provides a tool for selective ablation of pineal photoreceptor cells, i.e., by treatments with metronidazole. In the absence of pineal photoreceptor cells, the behavioral visual sensitivity of the fish remains unchanged; however, the circadian rhythms of rod and cone sensitivity are diminished. Brief light exposures restore the circadian rhythms of behavioral visual sensitivity. Together, the data suggest that retinal photoreceptor cells respond to environmental cues and are capable of entraining the circadian rhythms of visual sensitivity; however, they are insufficient for maintaining the rhythms. Cellular signals from the pineal photoreceptor cells may be required for maintaining the circadian rhythms of visual sensitivity. PMID:22815753

The influence of motor activity on the development of cardiac arrhythmias during experimental emotional stress

NASA Technical Reports Server (NTRS)

Ulyaninskiy, L. S.; Urmancheyeva, T. G.; Stepanyan, Y. P.; Fufacheva, A. A.; Gritsak, A. V.; Kuznetsova, B. A.; Kvitka, A. A.

1982-01-01

Experimental emotional stress which can produce various disorders of cardiac rhythm: sinus tachycardia, atrial fibrillation, ventricular, extrasystoles and paroxysmal ventricular tachysystoles was studied. In these conditions the adrenalin content in the blood and myocardium is increased 3 to 4 times. It is found that moderate motor activity leads to a relative decrease of adrenalin in the myocardium and arrest of cardiac arrhythmias.

The why, when and how to test for obstructive sleep apnea in patients with atrial fibrillation.

PubMed

Desteghe, Lien; Hendriks, Jeroen M L; McEvoy, R Doug; Chai-Coetzer, Ching Li; Dendale, Paul; Sanders, Prashanthan; Heidbuchel, Hein; Linz, Dominik

2018-04-12

Sleep apnea is associated with increased cardiovascular risk and may be important in atrial fibrillation (AF) management. It is present in up to 62% of the AF population and is highly under-recognized and underdiagnosed. Obstructive sleep apnea (OSA) is strongly associated with AF and non-randomized trials have shown that its treatment can help to reduce AF recurrences and maintain sinus rhythm. The 2016 European Society of Cardiology guidelines for the management of AF recommend that AF patients should be questioned regarding the symptoms of OSA and that OSA-treatment should be optimized to improve AF treatment results. However, strategies on how to implement OSA testing in the standard work-up of AF patients are not provided in the guidelines. Additionally, overnight OSA monitoring rather than interrogation for OSA-related clinical signs alone may be necessary to reliably identify OSA in the majority of AF patients. This review summarizes the available clinical data on OSA in AF patients, and discusses the following key questions: Why and When is testing for OSA needed in AF patients? How and Where should it be performed and coordinated? and Who should test for OSA? To implement OSA testing in a cardiology or electrophysiology clinic, we propose a multidisciplinary integrated care approach based on a chronic care model. We describe the tools, infrastructure and coordination needed to test for OSA in the standard workup of patients with symptomatic AF prior to the initiation of directed invasive or pharmacological rhythm control management.

Arrhythmia Mechanism and Scaling Effect on the Spectral Properties of Electroanatomical Maps With Manifold Harmonics.

PubMed

Sanroman-Junquera, Margarita; Mora-Jimenez, Inmaculada; Garcia-Alberola, Arcadio; Caamano, Antonio J; Trenor, Beatriz; Rojo-Alvarez, Jose L

2018-04-01

Spatial and temporal processing of intracardiac electrograms provides relevant information to support the arrhythmia ablation during electrophysiological studies. Current cardiac navigation systems (CNS) and electrocardiographic imaging (ECGI) build detailed 3-D electroanatomical maps (EAM), which represent the spatial anatomical distribution of bioelectrical features, such as activation time or voltage. We present a principled methodology for spectral analysis of both EAM geometry and bioelectrical feature in CNS or ECGI, including their spectral representation, cutoff frequency, or spatial sampling rate (SSR). Existing manifold harmonic techniques for spectral mesh analysis are adapted to account for a fourth dimension, corresponding to the EAM bioelectrical feature. Appropriate scaling is required to address different magnitudes and units. With our approach, simulated and real EAM showed strong SSR dependence on both the arrhythmia mechanism and the cardiac anatomical shape. For instance, high frequencies increased significantly the SSR because of the "early-meets-late" in flutter EAM, compared with the sinus rhythm. Besides, higher frequency components were obtained for the left atrium (more complex anatomy) than for the right atrium in sinus rhythm. The proposed manifold harmonics methodology opens the field toward new signal processing tools for principled EAM spatiofeature analysis in CNS and ECGI, and to an improved knowledge on arrhythmia mechanisms.

Effect of verapamil on immediate recurrence of atrial fibrillation.

PubMed

Daoud, E G; Hummel, J D; Augostini, R; Williams, S; Kalbfleisch, S J

2000-11-01

The purpose of this study was to assess the effect of verapamil on immediate recurrences of atrial fibrillation occurring after successful electrical cardioversion. The effect of verapamil on the recurrence of atrial fibrillation within 5 minutes after successful transthoracic cardioversion was assessed in 19 (5%) of 364 patients undergoing electrical cardioversion. The mean duration of atrial fibrillation was 4.44+/-3.0 months. In the 19 patients, cardioversion was successful after each of three consecutive cardioversion attempts per patient; however, atrial fibrillation recurred 0.4+/-0.3 minutes after cardioversion. Verapamil 10 mg was administered intravenously and a fourth cardioversion was performed. Cardioversion after verapamil was successful in each patient, and atrial fibrillation did not recur in 9 (47%) of 19 patients (P < 0.001 vs before verapamil). In the remaining 10 patients in whom atrial fibrillation recurred, the duration of sinus rhythm was significantly longer compared with before verapamil (3.6+/-2.4 min, P < 0.001). The density of atrial ectopy occurring after cardioversion was significantly less after verapamil (21+/-14 ectopic beats per min) compared with before verapamil (123+/-52 ectopic beats per min, P < 0.001). Among patients with immediate recurrence of atrial fibrillation after electrical cardioversion, acute calcium channel blockade by verapamil reduces recurrence of atrial fibrillation and extends the duration of sinus rhythm.

Safety and efficacy of vernakalant for acute cardioversion of atrial fibrillation: an update

PubMed Central

Tsuji, Yukiomi; Dobrev, Dobromir

2013-01-01

Intravenous vernakalant has recently been approved in Europe as an atrial-selective antiarrhythmic drug for the conversion of recent-onset atrial fibrillation (AF). It inhibits atrial-selective K+ currents (IK,ACh and IKur) and causes rate-dependent atrial-predominant Na+ channel block, with only a small inhibitory effect on the rapid delayed rectifier K+ current (IKr) in the ventricle. Due to its atrial-selective properties, vernakalant prolongs the effective refractory period of the atria with minimal effects on the ventricles, being associated with a low proarrhythmic risk for torsades de pointes arrhythmias. Five pivotal clinical trials consistently demonstrated that vernakalant rapidly terminates AF with stable maintenance of sinus rhythm for up to 24 hours. A head-to-head comparative trial showed that the 90-minute conversion rate of vernakalant was substantially higher than that of amiodarone. Initially, a longer-acting oral formulation of vernakalant was shown to be effective and safe in preventing AF recurrence after cardioversion in a Phase IIb study. However, the clinical studies testing oral vernakalant for maintenance of sinus rhythm after AF cardioversion were prematurely halted for undisclosed reasons. This review article provides an update on the safety and efficacy of intravenous vernakalant for the rapid cardioversion of AF. PMID:23637539

Endoscopic Modified Medial Maxillectomy for Fungal Ball of the Hypoplastic Maxillary Sinus With Bony Hypertrophy.

PubMed

Nomura, Kazuhiro; Ikushima, Hiroyuki; Ozawa, Daiki; Shimizu, Yuichi; Arakawa, Kazuya; Suzuki, Jun; Hidaka, Hiroshi; Katori, Yukio; Ohyama, Kenji

2018-05-01

Sinus fungal ball is defined as noninvasive chronic rhino-sinusitis with a clump of mold in the paranasal sinuses, typically affecting the maxillary sinus. Fairly good outcomes of endoscopic surgery have been reported where the ball is removed through the antrostomy. However, the affected sinus tends to have a smaller cavity and thicker bony walls. As such, it is often challenging to maintain a window size that is sufficient to control possible recurrence. The endoscopic modified medial maxillectomy procedure was applied to a 61-year old and a 70-year old female patient with maxillary sinus fungal ball. Using this method, we created a much larger inferior meatal antrostomy without difficulty. The window provided us with an endoscopic view of the whole sinus and complete eradication of the lesion. Endoscopic modified medial maxillectomy is useful as a surgical procedure for maxillary sinus fungal ball and should be considered for better outcomes.

Real-time dominant frequency mapping and ablation of dominant frequency sites in atrial fibrillation with left-to-right frequency gradients predicts long-term maintenance of sinus rhythm.

PubMed

Atienza, Felipe; Almendral, Jesús; Jalife, José; Zlochiver, Sharon; Ploutz-Snyder, Robert; Torrecilla, Esteban G; Arenal, Angel; Kalifa, Jérôme; Fernández-Avilés, Francisco; Berenfeld, Omer

2009-01-01

Spectral analysis identifies localized sites of high-frequency activity during atrial fibrillation (AF). This study sought to determine the effectiveness of using real-time dominant frequency (DF) mapping for radiofrequency ablation of maximal DF (DFmax) sites and elimination of left-to-right frequency gradients in the long-term maintenance of sinus rhythm (SR) in AF patients. DF mapping was performed in 50 patients during ongoing AF (32 paroxysmal, 18 persistent), acquiring a mean of 117 +/- 38 points. Ablation was performed targeting DFmax sites, followed by circumferential pulmonary vein isolation. Ablation significantly reduced DFs (Hz) in the LA (7.9 +/- 1.4 vs. 5.7 +/- 1.3, P <.001), coronary sinus (CS) (5.7 +/- 1.1 vs. 5.3 +/- 1.2, P = .006), and RA (6.3 +/- 1.4 vs. 5.4 +/- 1.3, P <.001) abolishing baseline left-to-right atrial DF gradient (1.7 +/- 1.7 vs. 0.2 +/- 0.9; P <.001). Only a significant reduction in DFs in all chambers with a loss of the left-to-right atrial gradient after ablation was associated with a higher probability of long-term SR maintenance in both paroxysmal and persistent AF patients. After a mean follow-up of 9.3 +/- 5.4 months, 88% of paroxysmal and 56% of persistent AF patients were free of AF (P = .02). Ablation of DFmax sites was associated with a higher probability of remaining both free of arrhythmias (78% vs. 20%; P = .001) and free of AF (88% vs. 30%; P <.001). Radiofrequency ablation leading to elimination of LA-to-RA frequency gradients predicts long-term SR maintenance in AF patients.

New in vitro model for proarrhythmia safety screening: IKs inhibition potentiates the QTc prolonging effect of IKr inhibitors in isolated guinea pig hearts.

PubMed

Kui, Péter; Orosz, Szabolcs; Takács, Hedvig; Sarusi, Annamária; Csík, Norbert; Rárosi, Ferenc; Csekő, Csongor; Varró, András; Papp, Julius Gy; Forster, Tamás; Farkas, Attila S; Farkas, András

2016-01-01

Preclinical in vivo QT measurement as a proarrhythmia essay is expensive and not reliable enough. The aim of the present study was to develop a sensitive, cost-effective, Langendorff perfused guinea pig heart model for proarrhythmia safety screening. Low concentrations of dofetilide and cisapride (inhibitors of the rapid delayed rectifier potassium current, IKr) were tested alone and co-perfused with HMR-1556 (inhibitor of the slow delayed rectifier potassium current, IKs) in Langendorff perfused guinea pig hearts. The electrocardiographic rate corrected QT (QTc) interval, the Tpeak-Tend interval and the beat-to-beat variability and instability (BVI) of the QT interval were determined in sinus rhythm. Dofetilide and HMR-1556 alone or co-perfused, prolonged the QTc interval by 20±2%, 10±1% and 55±10%, respectively. Similarly, cisapride and HMR-1556 alone or co-perfused, prolonged the QTc interval by 11±3%, 11±4% and 38±6%, respectively. Catecholamine-induced fast heart rate abolished the QTc prolonging effects of the IKr inhibitors, but augmented the QTc prolongation during IKs inhibition. None of the drug perfusions increased significantly the Tpeak-Tend interval and the sinus BVI of the QT interval. IKs inhibition increased the QTc prolonging effect of IKr inhibitors in a super-additive (synergistic) manner, and the QTc interval was superior to other proarrhythmia biomarkers measured in sinus rhythm in isolated guinea pig hearts. The effect of catecholamines on the QTc facilitated differentiation between IKr and IKs inhibitors. Thus, QTc measurement in Langendorff perfused guinea pig hearts with pharmacologically attenuated repolarization reserve and periodic catecholamine perfusion seems to be suitable for preclinical proarrhythmia screening. Copyright © 2016 Elsevier Inc. All rights reserved.

Seasonal and daily plasma corticosterone rhythms in American toads, Bufo americanus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pancak, M.K.; Taylor, D.H.

1983-06-01

Concentrations of corticosterone were measured in the plasma of American toads, Bufo americanus, on a seasonal basis using a radioimmunoassay technique. Two populations of toads, maintained under different light conditions, were monitored to observe the effects of photoperiod on the seasonal rhythm of plasma corticosterone. Under a natural photoperiod toads demonstrated a rhythm consisting of a spring peak and a fall peak in corticosterone concentration. Toads maintained under a 12L:12D photoperiod all year round demonstrated a similar rhythm with peaks in the spring and fall. This suggests that an endogenous (circannual) rhythm of corticosterone may be playing an important rolemore » in the seasonal change of overt behavior and physiology of Bufo americanus. A daily rhythm of corticosterone was also detected in toads when blood samples were taken every 4 hr. When compared to a previously published circadian rhythm study of locomotor activity, the surge in corticosterone concentration for the day occurred at 1730 just prior to the peak in locomotor activity.« less

Electrocardiograms with pacemakers: accuracy of computer reading.

PubMed

Guglin, Maya E; Datwani, Neeta

2007-04-01

We analyzed the accuracy with which a computer algorithm reads electrocardiograms (ECGs) with electronic pacemakers (PMs). Electrocardiograms were screened for the presence of electronic pacing spikes. Computer-derived interpretations were compared with cardiologists' readings. Computer-drawn interpretations required revision by cardiologists in 61.3% of cases. In 18.4% of cases, the ECG reading algorithm failed to recognize the presence of a PM. The misinterpretation of paced beats as intrinsic beats led to multiple secondary errors, including myocardial infarctions in varying localization. The most common error in computer reading was the failure to identify an underlying rhythm. This error caused frequent misidentification of the PM type, especially when the presence of normal sinus rhythm was not recognized in a tracing with a DDD PM tracking the atrial activity. The increasing number of pacing devices, and the resulting number of ECGs with pacing spikes, mandates the refining of ECG reading algorithms. Improvement is especially needed in the recognition of the underlying rhythm, pacing spikes, and mode of pacing.

[Late arrhythmias in the operated interatrial communication. Analysis of sinus node function and the conduction pathways by His bundle electrocardiography].

PubMed

Ramírez, A; Gil, M; Martínez Ríos, M A; Cárdenas, M; Pliego, J; Zamora, C; Mata, L A

1982-01-01

Four hundred patients with atrial septal defect treated surgically were reviewed. Thirty five (8.7%) developed arrhytmias post-surgery which persisted for over a year. Sinus bradycardia was found in 10 patients, nodal rhythm in 21, and atrial fibrilation and flutter in 4 patients. Thirty five per cent of the patients with late arrhythmias developed related symptomatology. In 14 patients the function of the sinus node was studied with electrical stimulation of the atrium and with His registry. The interatrial conduction time, AV node and His Purkinje were analized employing various stimulation frequencies. All the cases studied had normal intra-atrial conduction; the response of the atrio-ventricular node to increasing frequencies was normal, an the intraventricular conduction remained constant. In 8 patients (52%), alterations of the sinus node were found; these consisted of prolonged post-stimulation pauses, Wenckebach's type sinoatrial block and suppression of sinus automatism employing vagal procedures or through electrical stimulation. A patient with severe bradycardia detected by dynamic electrocardiography had to be treated with a permanent pacemaker. We confirm that these arrhytmias are not produced by lesions of the internodal tracts, and that an alteration of the sinus node is frequent without a concomitant lesion of the intraventricular pathway. The lesion to the nutrient artery could be due to trauma and/or surgically induced. The response to anticholinergic drugs was good. Prolonged observation of these patients could increase the morbility of these arrythmias and raise doubts of the surgical indications in cases with moderate hemodynamic repercussion.

Successful electrical cardioversion of supraventricular tachycardia in a pregnant patient

PubMed Central

Yılmaz, Fevzi; Beydilli, Inan; Kavalcı, Cemil; Yılmaz, Serkan

2012-01-01

Summary Background: Pregnancy can precipitate cardiac arrhythmias not previously present in seemingly well individuals. Atrial and ventricular premature beats are frequently present during pregnancy and are usually benign. Supraventricular tachycardia and malignant ventricular tachyarrhythmias occur less frequently. Maternal and fetal arrhythmias occurring during pregnancy may jeopardize the life of the mother and the fetus. Case Report: A 32-year-old pregnant women at 26 weeks gestation presented to the emergency department with palpitation. She had mild chest discomfort after a supraventricular tachycardia (SVT) episode but did not have syncope. After monitoring and access of an IV line, vagal manoeuvres were applied but the rhythm was resistant. Then she was treated with 5 mg metoprolol IV, but the SVT persisted. Then after IV infusion of adenosine triphosphate 6 to 12 mg, the rhythm was resistant. Synchronized cardioversion with 100 joules was performed. Patients’ rhythm was normalized to a sinus rhythm. She was discharged from hospital without any adverse effects following 24-hour monitoring. Conclusions: All pregnant patients with SVT require careful maternal and fetal monitoring during treatment, and close collaboration between the managing obstetrician and the cardiologist is essential. PMID:23569481

The role of HATCH score in predicting the success rate of sinus rhythm following electrical cardioversion of atrial fibrillation.

PubMed

Emren, Sadık Volkan; Kocabaş, Uğur; Duygu, Hamza; Levent, Fatih; Şimşek, Ersin Çağrı; Yapan Emren, Zeynep; Tülüce, Selcen

2016-01-01

The HATCH score predicts the development of persistent and permanent atrial fibrillation (AF) one year after spontaneous or pharmacological conversion to sinus rhythm in patients with AF. However, it remains unknown whether HATCH score predicts short-term success of the procedure at early stages for patients who have undergone electrical cardioversion (EC) for AF. The present study evaluated whether HATCH score predicts short-term success of EC in patients with AF. The study included patients aged 18 years and over, who had undergone EC due to AF lasting less than 12 months, between December 2011 and October 2013. HATCH score was calculated for all patients. The acronym HATCH stands for Hypertension, Age (above 75 years), Transient ischaemic attack or stroke, Chronic obstructive pulmonary disease, and Heart failure. This scoring system awards two points for heart failure and transient ischaemic attack or stroke and one point for the remaining items. The study included 227 patients and short-term EC was successful in 163 of the cases. The mean HATCH scores of the patients who had undergone successful or unsuccessful EC were 1.3 ± 1.4 and 2.9 ± 1.4, respectively (p < 0.001). The area of the HATCH score under the curve in receiver operating characteristics analysis was (AUC) 0.792 (95% CI 0.727-0.857, p < 0.001). A HATCH score of two and above yielded 77% sensitivity, 62% specificity, 56% positive predictive value, and 87% negative predictive value in predicting unsuccessful cardioversion. HATCH score is useful in predicting short-term success of EC at early stages for patients with AF, for whom the use of a rhythm-control strategy is planned.

Ventricular Tachycardia or not? An Unexpected Reason of Wide QRS Complex Tachycardia in a Young Healthy Man: Sodium Bicarbonate.

PubMed

Eyuboglu, Mehmet

2016-10-01

Ventricular tachycardia (VT) is life-threatening subgroup of wide QRS complex tachycardia (WCT). VT is usually associated with structural heart diseases, but it can occur in the absence of any cardiovascular diseases. Adverse cardiac effect of sodium bicarbonate in healthy subjects is not well described. A 30-year-old healthy man with excessive intake of sodium bicarbonate-related VT is presented. He was using sodium bicarbonate during last 2 months to lose weight. He has no risk factors and any cardiovascular or systemic diseases. After intravenous administration of amiodarone, tachycardia ended and his rhythm converted to sinus rhythm with normal electrocardiogram. Patient is asymptomatic, and no VT was observed without any medications at 1 year of follow-up.

The electrophysiologic properties of esmolol, a short acting beta-blocker.

PubMed

Greenspan, A M; Spielman, S R; Horowitz, L N; Laddu, A; Senior, S

1988-04-01

Although beta-blockers have established efficacy in treating ventricular ectopy and PSVT, their applicability for acute antiarrhythmic interventions in patients with organic heart disease or COPD, is frequently limited by negative inotropic or bronchospastic side effects. The development of an ultrashort acting beta-blocker with rapid reversibility of its side effects would widen their applicability. Therefore, we tested the electrophysiologic properties of such a new short acting beta-blocker, esmolol, in 14 patients (10 with organic heart disease) with a mean EF of 47.6 +/- 17%, undergoing standard clinical electrophysiologic studies for various indications. Like most other beta-blockers, esmolol's major direct effects were on sinus node function and AV nodal conduction characteristics; significantly prolonging sinus cycle length, cycle length to Wenckebach and AH interval in sinus rhythm and at a paced cycle length of 600 ms. In contrast to most other beta-blockers, following termination of its infusion, esmolol shortened parameters of sinus node function and AV nodal refractoriness, with respect to the control values, suggesting a possible rebound phenomena. These effects occurred within 5 min of terminating the intravenous drug infusion. Esmolol had no significant effect on systolic blood pressure, electrocardiographic intervals and had rare adverse reactions. We conclude that esmolol is an ultra-short acting beta-blocker, with typical direct electrophysiologic effects on sinus node and AV nodal function, and a possible rebound phenomena following its discontinuation that may make it particularly suited to acute antiarrhythmic interventions in patients susceptible to adverse beta-blocker side effects.

ECG signal quality during arrhythmia and its application to false alarm reduction.

PubMed

Behar, Joachim; Oster, Julien; Li, Qiao; Clifford, Gari D

2013-06-01

An automated algorithm to assess electrocardiogram (ECG) quality for both normal and abnormal rhythms is presented for false arrhythmia alarm suppression of intensive care unit (ICU) monitors. A particular focus is given to the quality assessment of a wide variety of arrhythmias. Data from three databases were used: the Physionet Challenge 2011 dataset, the MIT-BIH arrhythmia database, and the MIMIC II database. The quality of more than 33 000 single-lead 10 s ECG segments were manually assessed and another 12 000 bad-quality single-lead ECG segments were generated using the Physionet noise stress test database. Signal quality indices (SQIs) were derived from the ECGs segments and used as the inputs to a support vector machine classifier with a Gaussian kernel. This classifier was trained to estimate the quality of an ECG segment. Classification accuracies of up to 99% on the training and test set were obtained for normal sinus rhythm and up to 95% for arrhythmias, although performance varied greatly depending on the type of rhythm. Additionally, the association between 4050 ICU alarms from the MIMIC II database and the signal quality, as evaluated by the classifier, was studied. Results suggest that the SQIs should be rhythm specific and that the classifier should be trained for each rhythm call independently. This would require a substantially increased set of labeled data in order to train an accurate algorithm.

The Importance of Purkinje Activation in Long Duration Ventricular Fibrillation

PubMed Central

Huang, Jian; Dosdall, Derek J.; Cheng, Kang‐An; Li, Li; Rogers, Jack M.; Ideker, Raymond E.

2014-01-01

Background The mechanisms that maintain long duration ventricular fibrillation (LDVF) are unclear. The difference in distribution of the Purkinje system in dogs and pigs was explored to determine if Purkinje activation propagates to stimulate working myocardium (WM) during LDVF and WM pacing. Methods and Results In‐vivo extracellular recordings were made from 1044 intramural plunge and epicardial plaque electrodes in 6 pig and 6 dog hearts. Sinus activation propagated sequentially from the endocardium to the epicardium in dogs but not pigs. During epicardial pacing, activation propagated along the endocardium and traversed the LV wall almost parallel to the epicardium in dogs, but in pigs propagated away from the pacing site approximately perpendicular to the epicardium. After 1 minute of VF, activation rate near the endocardium was significantly faster than near the epicardium in dogs (P<0.01) but not pigs (P>0.05). From 2 to 10 minutes of LDVF, recordings exhibiting Purkinje activations were near the endocardium in dogs (P<0.01) but were scattered transmurally in pigs, and the WM activation rate in recordings in which Purkinje activations were present was significantly faster than the WM activation rate in recordings in which Purkinje activations were absent (P<0.01). In 10 isolated perfused dog hearts, the LV endocardium was exposed and 2 microelectrodes were inserted into Purkinje and adjacent myocardial cells. After 5 minutes of LDVF, mean Purkinje activation rate was significantly faster than mean WM activation rate (P<0.01). Conclusion These extracellular and intracellular findings about activation support the hypothesis that Purkinje activation propagates to stimulate WM during sinus rhythm, pacing, and LDVF. PMID:24584738

Survival after shock therapy in implantable cardioverter-defibrillator and cardiac resynchronization therapy-defibrillator recipients according to rhythm shocked. The ALTITUDE survival by rhythm study.

PubMed

Powell, Brian D; Saxon, Leslie A; Boehmer, John P; Day, John D; Gilliam, F Roosevelt; Heidenreich, Paul A; Jones, Paul W; Rousseau, Matthew J; Hayes, David L

2013-10-29

This study sought to determine if the risk of mortality associated with inappropriate implantable cardioverter-defibrillator (ICD) shocks is due to the underlying arrhythmia or the shock itself. Shocks delivered from ICDs are associated with an increased risk of mortality. It is unknown if all patients who experience inappropriate ICD shocks have an increased risk of death. We evaluated survival outcomes in patients with an ICD and a cardiac resynchronization therapy defibrillator enrolled in the LATITUDE remote monitoring system (Boston Scientific Corp., Natick, Massachusetts) through January 1, 2010. First shock episode rhythms from 3,809 patients who acutely survived the initial shock were adjudicated by 7 electrophysiologists. Patients with a shock were matched to patients without a shock (n = 3,630) by age at implant, implant year, sex, and device type. The mean age of the study group was 64 ± 13 years, and 78% were male. Compared with no shock, there was an increased rate of mortality in those who received their first shock for monomorphic ventricular tachycardia (hazard ratio [HR]: 1.65, p < 0.0001), ventricular fibrillation/polymorphic ventricular tachycardia (HR: 2.10, p < 0.0001), and atrial fibrillation/flutter (HR: 1.61, p = 0.003). In contrast, mortality after first shocks due to sinus tachycardia and supraventricular tachycardia (HR: 0.97, p = 0.86) and noise/artifact/oversensing (HR: 0.91, p = 0.76) was comparable to that in patients without a shock. Compared with no shock, those who received their first shock for ventricular rhythms and atrial fibrillation had an increased risk of death. There was no significant difference in survival after inappropriate shocks for sinus tachycardia or noise/artifact/oversensing. In this study, the adverse prognosis after first shock appears to be more related to the underlying arrhythmia than to an adverse effect from the shock itself. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Management and outcome of patients with acute myocardial infarction presenting with pacemaker rhythm.

PubMed

Bertel, Noemi; Witassek, Fabienne; Puhan, Milo; Erne, Paul; Rickli, Hans; Naegeli, Barbara; Pedrazzini, Giovanni; Stauffer, Jean-Christophe; Radovanovic, Dragana

2017-03-01

Diagnosis of acute myocardial infarction (MI) is challenging in pacemaker patients. Little is known about this patient group. Patients with MI enrolled in the Swiss national AMIS Plus registry between January 2005 and December 2015 were analyzed. All patients with either paced ventricular rhythm or sinus rhythm with intrinsic ventricular conduction (IVC) were included in this study. Outcomes using crude data and propensity score matching were compared between patients with pacemaker rhythm and patients with IVC. The primary endpoint was in-hospital death. Data from 300 patients with paced rhythm and 27,595 with IVC were analyzed. Patients with pacemaker rhythm were older (78.2y vs 65.4y; p<0.001), had more comorbidities (Charlson Index (CCI)>1: 54.0% vs 21.1%; p<0.001) and a higher rate of heart failure upon presentation (Killip class>2, 11.0% vs 5.9%; p<0.001) compared to patients with IVC. Door to balloon time in patients undergoing acute PCI is markedly delayed in contrast to patients with IVC (280min vs 85min; p<0.001). Consequently, crude mortality in patients with pacemakers was high (11.3% vs 4.6%; p<0.001). However, when analyzed with propensity matching for gender, age, CCI>1 and Killip>2, mortality was similar (11.2% vs 10.5%; p=0.70). Pacemaker patients with acute MI represent a high-risk group with doubled crude mortality compared to patients without pacemakers, due to higher age and higher Killip class. Diagnosis is difficult and results in delayed treatment. Treatment algorithms for MI with paced rhythm should possibly be adapted to those used for STEMI or new left bundle branch block. NCT01305785. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Heartbeat Cycle Length Detection by a Ballistocardiographic Sensor in Atrial Fibrillation and Sinus Rhythm

PubMed Central

Zink, Matthias Daniel; Brüser, Christoph; Winnersbach, Patrick; Napp, Andreas; Leonhardt, Steffen; Marx, Nikolaus; Schauerte, Patrick; Mischke, Karl

2015-01-01

Background. Heart rate monitoring is especially interesting in patients with atrial fibrillation (AF) and is routinely performed by ECG. A ballistocardiography (BCG) foil is an unobtrusive sensor for mechanical vibrations. We tested the correlation of heartbeat cycle length detection by a novel algorithm for a BCG foil to an ECG in AF and sinus rhythm (SR). Methods. In 22 patients we obtained BCG and synchronized ECG recordings before and after cardioversion and examined the correlation between heartbeat characteristics. Results. We analyzed a total of 4317 heartbeats during AF and 2445 during SR with a correlation between ECG and BCG during AF of r = 0.70 (95% CI 0.68–0.71, P < 0.0001) and r = 0.75 (95% CI 0.73–0.77, P < 0.0001) during SR. By adding a quality index, artifacts could be reduced and the correlation increased for AF to 0.76 (95% CI 0.74–0.77, P < 0.0001, n = 3468) and for SR to 0.85 (95% CI 0.83–0.86, P < 0.0001, n = 2176). Conclusion. Heartbeat cycle length measurement by our novel algorithm for BCG foil is feasible during SR and AF, offering new possibilities of unobtrusive heart rate monitoring. This trial is registered with IRB registration number EK205/11. This trial is registered with clinical trials registration number NCT01779674. PMID:26229965

Surgical treatment of atrial fibrillation.

PubMed

Pagé, Pierre; Skanes, Allan C

2005-09-01

Surgery aims to eliminate atrial fibrillation (AF) through direct modification of the arrhythmogenic substratum. The Maze procedure, developed two decades ago, has proven to be clearly effective in restoring sinus rhythm in AF patients with or without associated organic cardiac disorders. Indications for surgery may be tailored to the clinical situation involved. In patients with continuous AF associated with structural heart disease (eg, valvular, congenital or coronary artery disease), the performance of a concomitant AF ablation procedure proven to add minimal morbidity to the operation may be highly beneficial to patient outcome. It is likely, although not entirely proven, that the restoration and maintenance of sinus rhythm after mitral valve surgery promotes survival by preventing tachycardia-induced cardiomyopathy and stroke. Novel strategies for AF surgery involve the use of alternate energy sources to create the lines of block in the atria and the simplification of the lesion pattern compared with the earlier Cox-Maze procedure. Published clinical data support the contention that left atrial ablation techniques performed concomitantly with valvular and/or coronary artery bypass surgery are likely to result in a 70% to 90% cure rate of AF in patients with preoperatively documented AF. Despite the lack of evidence for long-term outcome benefit, intraoperative pulmonary vein ablation, feasible with minimal morbidity, clearly appears to be an improvement over simply ignoring AF in patients undergoing cardiac surgery. Left atrial appendectomy appears warranted in patients with chronic persistent AF.

An intelligent telecardiology system using a wearable and wireless ECG to detect atrial fibrillation.

PubMed

Lin, Chin-Teng; Chang, Kuan-Cheng; Lin, Chun-Ling; Chiang, Chia-Cheng; Lu, Shao-Wei; Chang, Shih-Sheng; Lin, Bor-Shyh; Liang, Hsin-Yueh; Chen, Ray-Jade; Lee, Yuan-Teh; Ko, Li-Wei

2010-05-01

This study presents a novel wireless, ambulatory, real-time, and autoalarm intelligent telecardiology system to improve healthcare for cardiovascular disease, which is one of the most prevalent and costly health problems in the world. This system consists of a lightweight and power-saving wireless ECG device equipped with a built-in automatic warning expert system. This device is connected to a mobile and ubiquitous real-time display platform. The acquired ECG signals are instantaneously transmitted to mobile devices, such as netbooks or mobile phones through Bluetooth, and then, processed by the expert system. An alert signal is sent to the remote database server, which can be accessed by an Internet browser, once an abnormal ECG is detected. The current version of the expert system can identify five types of abnormal cardiac rhythms in real-time, including sinus tachycardia, sinus bradycardia, wide QRS complex, atrial fibrillation (AF), and cardiac asystole, which is very important for both the subjects who are being monitored and the healthcare personnel tracking cardiac-rhythm disorders. The proposed system also activates an emergency medical alarm system when problems occur. Clinical testing reveals that the proposed system is approximately 94% accurate, with high sensitivity, specificity, and positive prediction rates for ten normal subjects and 20 AF patients. We believe that in the future a business-card-like ECG device, accompanied with a mobile phone, can make universal cardiac protection service possible.

[Pulmonary artery pressure evaluation in adults by Doppler echocardiography].

PubMed

Campos Filho, O; Andrade, J L; Carvalho, A C; Luna Filho, B; Pfeferman, A; Arroyo, J B; Leão, L E; Martinez Filho, E E

1991-04-01

To assess the role of pulsed Doppler echocardiography (PDE) in the indirect assessment of pulmonary artery (PA) pressure (P), analysing the pulmonary velocity blood flow curves (PVBFC) profile. Sixty-one adults with several kinds of heart disease were submitted to heart catheterization to obtain PAP (systolic, diastolic, mean), and other hemodynamic variables. A PDE examination was performed in all to obtain the PVBFC at the level of the pulmonic annulus. Qualitative features of the curve were analysed (morphological pattern, presence of pulmonic regurgitation) as well as quantitative data (acceleration time = AT, right ventricle ejection time = RVET index, AT/RVET index AT corrected for heart rate = ATC), which were compared to the invasive measurements. An abnormal rapid acceleration of the PVBFC, with triangular configuration, was noted in patient with pulmonary hypertension (PH), in contrast to the dome-like shape of the PVBFC in normal PAP. Pulmonary regurgitation was more frequent (p less than 0.05) in patients with severe PH (mean PAP greater than or equal to 40 mmHg), comparing with patients with PAP less than 40 mmHg. Inverse linear correlations were observed between AT and mean PAP, particularly when sinus rhythm was present (r = 0.89; p less than 0.05) excluding patients with atrial fibrilation (19 cases). PDE is an useful and noninvasive method for indirect evaluation of PAP in adults, especially during stable sinus rhythm, in heart rate range from 60 to 115 bpm.

Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

PubMed

Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

2014-01-01

Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals.

Simultaneous Epicardial and Noncontact Endocardial Mapping of the Canine Right Atrium: Simulation and Experiment

PubMed Central

Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J. Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

2014-01-01

Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals. PMID:24598778

Effects of atrial fibrillation on myocardial washout rate of thallium-201 on myocardial perfusion single-photon emission computed tomography.

PubMed

Kurisu, Satoshi; Nitta, Kazuhiro; Sumimoto, Yoji; Ikenaga, Hiroki; Ishibashi, Ken; Fukuda, Yukihiro; Kihara, Yasuki

2018-04-20

Myocardial perfusion single-photon emission computed tomography (SPECT) with thallium (Tl)-201 is an established modality for evaluating myocardial ischemia. We assessed the effects of atrial fibrillation (AF) on the myocardial washout rate (WR) of Tl-201 on myocardial perfusion SPECT. A total of 231 patients with no evidence of myocardial ischemia were enrolled retrospectively in this study. Patients were divided into two groups on the basis of the ECG at the time of myocardial perfusion SPECT. The mean myocardial WR of Tl-201 was calculated from the stress and the redistribution Bull's eye maps. There were 34 patients with AF and 197 patients with sinus rhythm. There were no significant differences in clinical variables, except for older age and higher heart rate in patients with AF. Myocardial WR of Tl-201 was significantly lower in patients with AF than those with sinus rhythm (46±12 vs. 51±8%, P=0.03). Multivariate analysis including these factors showed that female sex (β=0.18, P=0.02), AF (β=-0.14 P=0.03), hemoglobin (β=-0.18, P<0.01), and serum creatinine (β=0.24, P<0.01) were determinants of myocardial WR of Tl-201. Our data suggest that AF is associated with reduced myocardial WR of Tl-201 on myocardial perfuison SPECT.

Late Results of Cox Maze III Procedure in Patients with Atrial Fibrillation Associated with Structural Heart Disease.

PubMed

Gomes, Gustavo Gir; Gali, Wagner Luis; Sarabanda, Alvaro Valentim Lima; Cunha, Claudio Ribeiro da; Kessler, Iruena Moraes; Atik, Fernando Antibas

2017-07-01

Cox-Maze III procedure is one of the surgical techniques used in the surgical treatment of atrial fibrillation (AF). To determine late results of Cox-Maze III in terms of maintenance of sinus rhythm, and mortality and stroke rates. Between January 2006 and January 2013, 93 patients were submitted to the cut-and-sew Cox-Maze III procedure in combination with structural heart disease repair. Heart rhythm was determined by 24-hour Holter monitoring. Procedural success rates were determined by longitudinal methods and recurrence predictors by multivariate Cox regression models. Thirteen patients that obtained hospital discharge alive were excluded due to lost follow-up. The remaining 80 patients were aged 49.9 ± 12 years and 47 (58.7%) of them were female. Involvement of mitral valve and rheumatic heart disease were found in 67 (83.7%) and 63 (78.7%) patients, respectively. Seventy patients (87.5%) had persistent or long-standing persistent AF. Mean follow-up with Holter monitoring was 27.5 months. There were no hospital deaths. Sinus rhythm maintenance rates were 88%, 85.1% and 80.6% at 6 months, 24 months and 36 months, respectively. Predictors of late recurrence of AF were female gender (HR 3.52; 95% CI 1.21-10.25; p = 0.02), coronary artery disease (HR 4.73 95% CI 1.37-16.36; p = 0.01) and greater left atrium diameter (HR 1.05; 95% CI 1.01-1.09; p = 0.02). Actuarial survival was 98.5% at 12, 24 and 48 months and actuarial freedom from stroke was 100%, 100% and 97.5% in the same time frames. The Cox-Maze III procedure, in our experience, is efficacious for sinus rhythm maintenance, with very low late mortality and stroke rates. A operação de Cox-Maze III é uma das variantes técnicas no tratamento cirúrgico da fibrilação atrial (FA). Estudar os resultados tardios da operação de Cox-Maze III, quanto à eficácia na manutenção de ritmo sinusal e taxas de mortalidade e acidente vascular cerebral (AVC). Entre janeiro de 2006 a janeiro de 2013, 93 pacientes foram submetidos a operação de Cox-Maze III por corte e sutura associada a correção de cardiopatias estruturais. Avaliação do ritmo cardíaco ocorreu por Holter 24 horas. Taxas de sucesso da operação foram estudadas por métodos longitudinais e os preditores de recorrência por análise de regressão de Cox multivariada. Foram excluídos 13 pacientes sobreviventes ao período intra-hospitalar cujo seguimento tardio não foi possível. Os 80 pacientes restantes tinham idade média de 49,9 ± 12 anos e 47 (58,75%) eram do sexo feminino. Acometimento da valva mitral ocorreu em 67 pacientes (83,7%). Valvopatia reumática ocorreu em 63 (78,7%). Setenta pacientes (87,5%) tinham fibrilação atrial persistente ou persistente de longa duração. O tempo médio de seguimento clínico com avaliação de Holter foi de 27,5 meses. Não houve óbitos intra-hospitalares. As taxas de manutenção de ritmo sinusal foram 88%, 85,1% e 80,6% aos 6 meses, 24 meses e 36 meses, respectivamente. Os preditores de recorrência tardia foram sexo feminino (RR 3,52; IC 95% 1,21-10,25; p = 0,02), doença arterial coronária (RR 4,73; IC 95% 1,37-16,36; p = 0,01) e maior diâmetro de átrio esquerdo (RR 1,05; IC 95% 1,01-1,09; p = 0,02). A sobrevida atuarial aos 12, 24 e 48 meses foi de 98,5% e as taxas atuariais livres de AVC nos mesmos períodos de 100%, 100% e 97,5%. A operação de Cox-Maze III, na nossa experiência, é eficaz na manutenção do ritmo sinusal, com baixíssimos índices de mortalidade e de AVC tardios.

Essential Role of the m2R-RGS6-IKACh Pathway in Controlling Intrinsic Heart Rate Variability

PubMed Central

Posokhova, Ekaterina; Ng, David; Opel, Aaisha; Masuho, Ikuo; Tinker, Andrew; Biesecker, Leslie G.; Wickman, Kevin; Martemyanov, Kirill A.

2013-01-01

Normal heart function requires generation of a regular rhythm by sinoatrial pacemaker cells and the alteration of this spontaneous heart rate by the autonomic input to match physiological demand. However, the molecular mechanisms that ensure consistent periodicity of cardiac contractions and fine tuning of this process by autonomic system are not completely understood. Here we examined the contribution of the m2R-IKACh intracellular signaling pathway, which mediates the negative chronotropic effect of parasympathetic stimulation, to the regulation of the cardiac pacemaking rhythm. Using isolated heart preparations and single-cell recordings we show that the m2R-IKACh signaling pathway controls the excitability and firing pattern of the sinoatrial cardiomyocytes and determines variability of cardiac rhythm in a manner independent from the autonomic input. Ablation of the major regulator of this pathway, Rgs6, in mice results in irregular cardiac rhythmicity and increases susceptibility to atrial fibrillation. We further identify several human subjects with variants in the RGS6 gene and show that the loss of function in RGS6 correlates with increased heart rate variability. These findings identify the essential role of the m2R-IKACh signaling pathway in the regulation of cardiac sinus rhythm and implicate RGS6 in arrhythmia pathogenesis. PMID:24204714

Wenxin Keli versus Sotalol for Paroxysmal Atrial Fibrillation Caused by Hyperthyroidism: A Prospective, Open Label, and Randomized Study

PubMed Central

Meng, Zhaowei; Tan, Jian; He, Qing; Zhu, Mei; Li, Xue; Zhang, Jianping; Jia, Qiang; Wang, Shen; Zhang, Guizhi; Zheng, Wei

2015-01-01

We aimed to compare effectiveness of Wenxin Keli (WK) and sotalol in assisting sinus rhythm (SR) restoration from paroxysmal atrial fibrillation (PAF) caused by hyperthyroidism, as well as in maintaining SR. We randomly prescribed WK (18 g tid) or sotalol (80 mg bid) to 91 or 89 patients. Since it was not ethical not to give patients antiarrhythmia drugs, no control group was set. Antithyroid drugs were given to 90 patients (45 in WK group, 45 in sotalol group); 131I was given to 90 patients (46 in WK group, 44 in sotalol group). Three months later, SR was obtained in 83/91 or 80/89 cases from WK or sotalol groups (P = 0.762). By another analysis, SR was obtained in 86/90 or 77/90 cases from 131I or ATD groups (P = 0.022). Then, we randomly assigned the successfully SR-reverted patients into three groups: WK, sotalol, and control (no antiarrhythmia drug was given) groups. After twelve-month follow-up, PAF recurrence happened in 1/54, 2/54, and 9/55 cases, respectively. Log-Rank test showed significant higher PAF recurrent rate in control patients than either treatment (P = 0.06). We demonstrated the same efficacies of WK and sotalol to assist SR reversion from hyperthyroidism-caused PAF. We also showed that either drug could maintain SR in such patients. PMID:26074982

Coronary sinus signal amplitude predicts left atrial scarring.

PubMed

Attanasio, Philipp; Qaiyumi, Daniel; Röhle, Robert; Wutzler, Alexander; Safak, Erdal; Muntean, Bogdan; Boldt, Leif-Hendrik; Pieske, Burkert; Haverkamp, Wilhelm; Huemer, Martin

2017-12-22

Left atrial scarring is recognised as a critical component in the maintenance of atrial fibrillation and is associated with the failure of interventional treatment. Diminished bipolar voltage (LV) has been proposed as a useful tool for left atrial scar quantification. We hypothesised that, due to its anatomic location, signals on the coronary sinus catheter might be used to predict the amount of left atrial low voltage. A total of 124 patients (42% women, average age 66 ± 9 years) were included. Forty-one with paroxysmal and 83 with persistent atrial fibrillation. Left atrial low-voltage (<0.5 mV, measured during sinus rhythm) area size and distribution varied considerably among the included patients (mean: 34.9%; maximum: 94.6%; minimum: 0.4%). Spearman correlation revealed a strong negative correlation between bipolar voltage of the signals on the coronary sinus catheter and the amount of left atrial scarring (R = -0.778, p < .0001). The optimal CS voltage cut off for prediction of left atrial low-voltage size of ≥50% was 1.9 mV with an area-under-the receiver-operating-characteristic (ROC) curve of 0.982, a sensitivity of 97% and a specificity of 98%. There is a strong negative correlation between the size of left atrial low-voltage areas (LVA) and coronary sinus signal amplitude. With increasing left atrial LVA size, CS signal amplitudes decrease, and vice versa. On the basis of these findings, average CS signal amplitudes of ≤1.9 mV can be used as a predictor for a left atrial low-voltage size of ≥50%.

Morpho-functional characterization of the systemic venous pole of the reptile heart.

PubMed

Jensen, Bjarke; Vesterskov, Signe; Boukens, Bastiaan J; Nielsen, Jan M; Moorman, Antoon F M; Christoffels, Vincent M; Wang, Tobias

2017-07-27

Mammals evolved from reptile-like ancestors, and while the mammalian heart is driven by a distinct sinus node, a sinus node is not apparent in reptiles. We characterized the myocardial systemic venous pole, the sinus venosus, in reptiles to identify the dominant pacemaker and to assess whether the sinus venosus remodels and adopts an atrium-like phenotype as observed in mammals. Anolis lizards had an extensive sinus venosus of myocardium expressing Tbx18. A small sub-population of cells encircling the sinuatrial junction expressed Isl1, Bmp2, Tbx3, and Hcn4, homologues of genes marking the mammalian sinus node. Electrical mapping showed that hearts of Anolis lizards and Python snakes were driven from the sinuatrial junction. The electrical impulse was delayed between the sinus venosus and the right atrium, allowing the sinus venosus to contract and aid right atrial filling. In proximity of the systemic veins, the Anolis sinus venosus expressed markers of the atrial phenotype Nkx2-5 and Gja5. In conclusion, the reptile heart is driven by a pacemaker region with an expression signature similar to that of the immature sinus node of mammals. Unlike mammals, reptiles maintain a sinuatrial delay of the impulse, allowing the partly atrialized sinus venosus to function as a chamber.

Cardiorespiratory interactions in patients with atrial flutter.

PubMed

Masè, Michela; Disertori, Marcello; Ravelli, Flavia

2009-01-01

Respiratory sinus arrhythmia (RSA) is generally known as the autonomically mediated modulation of the sinus node pacemaker frequency in synchrony with respiration. Cardiorespiratory interactions have been largely investigated during sinus rhythm, whereas little is known about interactions during reentrant arrhythmias. In this study, cardiorespiratory interactions at the atrial and ventricular level were investigated during atrial flutter (AFL), a supraventricular arrhythmia based on a reentry, by using cross-spectral analysis and computer modeling. The coherence and phase between respiration and atrial (gamma(AA)(2), phi(AA)) and ventricular (gamma(RR)(2), phi(RR)) interval series were estimated in 20 patients with typical AFL (68.0 +/- 8.8 yr) and some degree of atrioventricular (AV) conduction block. In all patients, atrial intervals displayed oscillations strongly coupled and in phase with respiration (gamma(AA)(2)= 0.97 +/- 0.05, phi(AA) = 0.71 +/- 0.31 rad), corresponding to a paradoxical lengthening of intervals during inspiration. The modulation pattern was frequency independent, with in-phase oscillations and short time delays (0.40 +/- 0.15 s) for respiratory frequencies in the range 0.1-0.4 Hz. Ventricular patterns were affected by AV conduction type. In patients with fixed AV conduction, ventricular intervals displayed oscillations strongly coupled (gamma(RR)(2)= 0.97 +/- 0.03) and in phase with respiration (phi(RR) = 1.08 +/- 0.80 rad). Differently, in patients with variable AV conduction, respiratory oscillations were secondary to Wencheback rhythmicity, resulting in a decreased level of coupling (gamma(RR)(2)= 0.50 +/- 0.21). Simulations with a simplified model of AV conduction showed ventricular patterns to originate from the combination of a respiratory modulated atrial input with the functional properties of the AV node. The paradoxical frequency-independent modulation pattern of atrial interval, the short time delays, and the complexity of ventricular rhythm characterize respiratory arrhythmia during AFL and distinguish it from normal RSA. These peculiar features can be explained by assuming a direct mechanical action of respiration on AFL reentrant circuit.

The role of feeding rhythm, adrenal hormones and neuronal inputs in synchronizing daily clock gene rhythms in the liver.

PubMed

Su, Yan; Cailotto, Cathy; Foppen, Ewout; Jansen, Remi; Zhang, Zhi; Buijs, Ruud; Fliers, Eric; Kalsbeek, Andries

2016-02-15

The master clock in the hypothalamic suprachiasmatic nucleus (SCN) is assumed to distribute rhythmic information to the periphery via neural, humoral and/or behavioral connections. Until now, feeding, corticosterone and neural inputs are considered important signals for synchronizing daily rhythms in the liver. In this study, we investigated the necessity of neural inputs as well as of the feeding and adrenal hormone rhythms for maintaining daily hepatic clock gene rhythms. Clock genes kept their daily rhythm when only one of these three signals was disrupted, or when we disrupted hepatic neuronal inputs together with the adrenal hormone rhythm or with the daily feeding rhythm. However, all clock genes studied lost their daily expression rhythm after simultaneous disruption of the feeding and adrenal hormone rhythm. These data indicate that either a daily rhythm of feeding or adrenal hormones should be present to synchronize clock gene rhythms in the liver with the SCN. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Prognosis of super-elderly healthy Japanese patients after pacemaker implantation for bradycardia.

PubMed

Yamaguchi, Tetsuo; Miyamoto, Takamichi; Iwai, Takamasa; Yamaguchi, Junji; Hijikata, Sadahiro; Miyazaki, Ryoichi; Miwa, Naoyuki; Sekigawa, Masahiro; Hara, Nobuhiro; Nagata, Yasutoshi; Nozato, Toshihiro; Yamauchi, Yasuteru; Obayashi, Toru; Isobe, Mitsuaki

2017-07-01

The prognosis of super-elderly patients (age≥85 years) who undergo bradycardia pacemaker (PM) implantation remains unknown. We retrospectively enrolled 868 patients (men 49.0%, 76.6±10.6 years) who could walk unassisted and whose expected life expectancy was more than 1 year, receiving their first bradycardia PM implantation between January 1, 2006, and June 30, 2013. Clinical outcomes were compared between super-elderly patients (n=201, mean age 88.6±3.2 years) and younger patients (n=667, 73.0±9.3 years). At the end of a median 1285-day follow-up, 128 patients (14.7%) died, of which 54 were cardiac deaths (42.2%). Mortality rates were similar between the groups (16.4% vs. 14.2%, log-rank p=0.56) and across different indications for implantation (atrio-ventricular conduction disturbance or sick sinus syndrome, p=0.59), initial rhythms (sinus rhythm or persistent atrial fibrillation, p=0.62), pacing modes (dual chamber pacing or VVI pacing, p=0.26), and ventricular lead positions (septum or apex, p=0.52). On Cox proportional hazard model analysis, hypertension [hazard ratio (HR)=1.74, 95% confidence interval (CI)=1.19-2.54, p=0.004], diabetes mellitus (HR=2.18, 95% CI=1.51-3.14, p<0.001), history of myocardial infarction (HR=3.59, 95% CI=2.49-5.16, p<0.001), and history of stroke (HR=2.26, 95% CI=1.51-3.37, p<0.001) were independent predictors for mortality. The mortality rate of super-elderly patients who had no critical illnesses and were healthy enough to walk unassisted at the time of PM implantation was not inferior to that of younger patients. Prognosis was determined by comorbidities, but not by age, PM indication, initial rhythm, pacing leads, or mode. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Comparing maximum rate and sustainability of pacing by mechanical vs. electrical stimulation in the Langendorff-perfused rabbit heart.

PubMed

Quinn, T Alexander; Kohl, Peter

2016-12-01

Mechanical stimulation (MS) represents a readily available, non-invasive means of pacing the asystolic or bradycardic heart in patients, but benefits of MS at higher heart rates are unclear. Our aim was to assess the maximum rate and sustainability of excitation by MS vs. electrical stimulation (ES) in the isolated heart under normal physiological conditions. Trains of local MS or ES at rates exceeding intrinsic sinus rhythm (overdrive pacing; lowest pacing rates 2.5±0.5 Hz) were applied to the same mid-left ventricular free-wall site on the epicardium of Langendorff-perfused rabbit hearts. Stimulation rates were progressively increased, with a recovery period of normal sinus rhythm between each stimulation period. Trains of MS caused repeated focal ventricular excitation from the site of stimulation. The maximum rate at which MS achieved 1:1 capture was lower than during ES (4.2±0.2 vs. 5.9±0.2 Hz, respectively). At all overdrive pacing rates for which repetitive MS was possible, 1:1 capture was reversibly lost after a finite number of cycles, even though same-site capture by ES remained possible. The number of MS cycles until loss of capture decreased with rising stimulation rate. If interspersed with ES, the number of MS to failure of capture was lower than for MS only. In this study, we demonstrate that the maximum pacing rate at which MS can be sustained is lower than that for same-site ES in isolated heart, and that, in contrast to ES, the sustainability of successful 1:1 capture by MS is limited. The mechanism(s) of differences in MS vs. ES pacing ability, potentially important for emergency heart rhythm management, are currently unknown, thus warranting further investigation. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.

Comparing maximum rate and sustainability of pacing by mechanical vs. electrical stimulation in the Langendorff-perfused rabbit heart

PubMed Central

Quinn, T. Alexander; Kohl, Peter

2016-01-01

Aims Mechanical stimulation (MS) represents a readily available, non-invasive means of pacing the asystolic or bradycardic heart in patients, but benefits of MS at higher heart rates are unclear. Our aim was to assess the maximum rate and sustainability of excitation by MS vs. electrical stimulation (ES) in the isolated heart under normal physiological conditions. Methods and results Trains of local MS or ES at rates exceeding intrinsic sinus rhythm (overdrive pacing; lowest pacing rates 2.5±0.5 Hz) were applied to the same mid-left ventricular free-wall site on the epicardium of Langendorff-perfused rabbit hearts. Stimulation rates were progressively increased, with a recovery period of normal sinus rhythm between each stimulation period. Trains of MS caused repeated focal ventricular excitation from the site of stimulation. The maximum rate at which MS achieved 1:1 capture was lower than during ES (4.2±0.2 vs. 5.9±0.2 Hz, respectively). At all overdrive pacing rates for which repetitive MS was possible, 1:1 capture was reversibly lost after a finite number of cycles, even though same-site capture by ES remained possible. The number of MS cycles until loss of capture decreased with rising stimulation rate. If interspersed with ES, the number of MS to failure of capture was lower than for MS only. Conclusion In this study, we demonstrate that the maximum pacing rate at which MS can be sustained is lower than that for same-site ES in isolated heart, and that, in contrast to ES, the sustainability of successful 1:1 capture by MS is limited. The mechanism(s) of differences in MS vs. ES pacing ability, potentially important for emergency heart rhythm management, are currently unknown, thus warranting further investigation. PMID:28011835

F-spondin Is Essential for Maintaining Circadian Rhythms

PubMed Central

Carrillo, Gabriela L.; Su, Jianmin; Monavarfeshani, Aboozar; Fox, Michael A.

2018-01-01

The suprachiasmatic nucleus (SCN) is the master pacemaker that drives circadian behaviors. SCN neurons have intrinsic, self-sustained rhythmicity that is governed by transcription-translation feedback loops. Intrinsic rhythms within the SCN do not match the day-night cycle and are therefore entrained by light-derived cues. Such cues are transmitted to the SCN by a class of intrinsically photosensitive retinal ganglion cells (ipRGCs). In the present study, we sought to identify how axons from ipRGCs target the SCN. While none of the potential targeting cues identified appeared necessary for retinohypothalamic innervation, we unexpectedly identified a novel role for the extracellular matrix protein F-spondin in circadian behavior. In the absence of F-spondin, mice lost their ability to maintain typical intrinsic rhythmicity. Moreover, F-spondin loss results in the displacement of vasoactive intestinal peptide (VIP)-expressing neurons, a class of neurons that are essential for maintaining rhythmicity among SCN neurons. Thus, this study highlights a novel role for F-spondin in maintaining circadian rhythms. PMID:29472844

Gene- and cell-based bio-artificial pacemaker: what basic and translational lessons have we learned?

PubMed Central

Li, RA

2012-01-01

Normal rhythms originate in the sino-atrial node, a specialized cardiac tissue consisting of only a few thousands of pacemaker cells. Malfunction of pacemaker cells due to diseases or aging leads to rhythm generation disorders (for example, bradycardias and sick-sinus syndrome (SSS)), which often necessitate the implantation of electronic pacemakers. Although effective, electronic devices are associated with such shortcomings as limited battery life, permanent implantation of leads, lead dislodging, the lack of autonomic responses and so on. Here, various gene- and cell-based approaches, with a particular emphasis placed on the use of pluripotent stem cells and the hyperpolarization-activated cyclic nucleotide-gated-encoded pacemaker gene family, that have been pursued in the past decade to reconstruct bio-artificial pacemakers as alternatives will be discussed in relation to the basic biological insights and translational regenerative potential. PMID:22673497

Gene- and cell-based bio-artificial pacemaker: what basic and translational lessons have we learned?

PubMed

Li, R A

2012-06-01

Normal rhythms originate in the sino-atrial node, a specialized cardiac tissue consisting of only a few thousands of nodal pacemaker cells. Malfunction of pacemaker cells due to diseases or aging leads to rhythm generation disorders (for example, bradycardias and sick-sinus syndrome (SSS)), which often necessitate the implantation of electronic pacemakers. Although effective, electronic devices are associated with such shortcomings as limited battery life, permanent implantation of leads, lead dislodging, the lack of autonomic responses and so on. Here, various gene- and cell-based approaches, with a particular emphasis placed on the use of pluripotent stem cells and the hyperpolarization-activated cyclic nucleotide-gated-encoded pacemaker gene family, that have been pursued in the past decade to reconstruct bio-artificial pacemakers as alternatives will be discussed in relation to the basic biological insights and translational regenerative potential.

A 2:1 AV rhythm: an adverse effect of a long AV delay during DDI pacing and its prevention by the ventricular intrinsic preference algorithm in DDD mode.

PubMed

Minamiguchi, Hitoshi; Oginosawa, Yasushi; Kohno, Ritsuko; Tamura, Masahito; Takeuchi, Masaaki; Otsuji, Yutaka; Abe, Haruhiko

2012-07-01

A 91-year-old woman received a dual-chamber pacemaker for sick sinus syndrome and intermittently abnormal atrioventricular (AV) conduction. The pacemaker was set in DDI mode with a 350-ms AV delay to preserve intrinsic ventricular activity. She complained of palpitation during AV sequential pacing. The electrocardiogram showed a 2:1 AV rhythm from 1:1 ventriculoatrial (VA) conduction during ventricular pacing in DDI mode with a long AV interval. After reprogramming of the pacemaker in DDD mode with a 250-ms AV interval and additional 100-ms prolongation of the AV interval by the ventricular intrinsic preference function, VA conduction disappeared and the patient's symptom were alleviated without increasing unnecessary right ventricular pacing. ©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.

Origins of timed cancer treatment: early marker rhythm-guided individualized chronochemotherapy*

PubMed Central

Halberg, Franz; Prem, Konald; Halberg, Francine; Norman, Catherine; Cornélissen, Germaine

2008-01-01

A 21-year old patient who presented in 1973 with a rare and highly malignant ovarian endodermal sinus tumor with spillage into the peritoneal cavity is alive and well today after receiving chronochemotherapy. During the first four courses of treatment, medications were given at different circadian stages. Complete blood counts and marker variables such as mood, vigor, nausea, and temperature were monitored around the clock and analyzed by cosinor to seek times of highest tolerance. Remaining treatment courses were administered at a time corresponding to the patient's best drug tolerance, rather than extrapolating the timing of optimal cyclophosphamide administration from also-implemented parallel laboratory studies on mice. Notwithstanding remaining hurdles in bringing chronochemotherapy to the clinic for routine care, merits of marker rhythm-guided chronotherapy documented in this and other case reports have led to the doubling of the two-year disease-free survival of patients with large perioral tumors in a clinical trial. PMID:17228525

Inappropriate bradycardia in Ebola virus disease.

PubMed

Cellarier, G; Bordes, J; De Greslan, T; Karkowski, L; Gagnon, N; Billhot, M; Cournac, J-M; Rousseau, C; Mac Nab, C; Dubrous, P

2016-08-01

As part of French assistance for the outbreak of Ebola virus disease in west Africa, a military treatment center for infected healthcare workers was deployed in Conakry, Guinea. Although some cases of bradycardia have been reported since the first Ebola outbreak, they have never been documented to our knowledge. We studied heart rhythm in patients with Ebola virus disease to analyze inappropriate bradycardia and discuss its mechanism. Nine patients who tested positive for Ebola were admitted in March 2015. Baseline clinical data were noted at admission and twice a day during follow-up, and laboratory analyses (with troponin testing) were performed. At admission, patients had no or moderate tachycardia (pulse = 82 ± 27 bpm). Among them, a 32-year-old midwife admitted on her fourth day of symptoms had marked bradycardia: 43 bpm. ECG showed sinus bradycardia with no conduction disturbances or repolarization anomalies; findings were similar for the three other patients with bradycardia (< 60 bpm). During follow-up, her pulse gradually increased, as it did for the other three; all four recovered. Despite several factors likely to promote tachycardia, we observed no or only moderate tachycardia in all patients with Ebola. In our study, ECG recorded sinus rhythm, without significant node dysfunction or atrioventricular block. In the absence of any evidence of myocarditis, we discuss the possibility of a central nervous system cause, associated with encephalitis. We observed relative or marked bradycardia in our patients infected with Ebola. We hypothesize that its causal mechanism was encephalitis.

Arrhythmia Secondary to Cold Water Submersion during Helicopter Underwater Escape Training.

PubMed

Kaur, Paven P; Drummond, Sarah E; Furyk, Jeremy

2016-02-01

A 32-year-old, fit and healthy, Caucasian male presented with a less than 24-hour history of palpitations with the onset following participation in helicopter underwater escape training (HUET). He reported no chest pain, shortness of breath, syncope, or pre-syncope symptoms. On examination, an irregularly irregular pulse was noted at a rate of 120 beats per minute with a blood pressure of 132/84. There was no evidence of congestive cardiac failure. The electrocardiogram (ECG) demonstrated atrial fibrillation at 97 beats per minute with a normal axis, normal QRS complexes, and a QTc of 399 ms. Bloods were all within normal limits and a chest x-ray showed no abnormality. The patient was loaded with amiodarone and reverted to sinus rhythm with a normal post-reversion ECG. Five years on, following further HUET, the patient presented with an identical presentation. His ECG showed fast atrial fibrillation at a rate of 115 beats per minute. On this occasion, he was sedated and Direct Current cardioverted with reversal to sinus rhythm after one shock. It was felt that the precipitating factor for this patient's atrial fibrillation, in both cases, was HUET. The case discussed describes a previously fit and well subject who developed a sustained arrhythmia secondary to cold water submersion. Evidence suggests water submersion can provoke cardiac arrhythmias via the suggested theory of "autonomic conflict." It has been proposed that a number of unexplained deaths related to water submersion may be secondary to arrhythmogenic syncope.

Outcome of stand-alone thoracoscopic epicardial left atrial posterior box isolation with bipolar radiofrequency energy for longstanding persistent atrial fibrillation.

PubMed

Compier, M G; Braun, J; Tjon, A; Zeppenfeld, K; Klautz, R J M; Schalij, M J; Trines, S A

2016-02-01

Catheter ablation of longstanding (> 1 year) persistent atrial fibrillation (AF) is associated with poor outcome. This might be due to remodelling and fibrosis formation, mainly located in the posterior left atrial (LA) wall. Therefore, we adopted a thoracoscopic epicardial box isolation of the posterior left atrium using bipolar RF energy with intraoperative testing of conduction block. Bilateral thoracoscopic box isolation was performed with a bipolar RF clamp. Entrance block was defined as absence of a conducted electrogram within the box, while exit block was confirmed by pacing at 10.0 V/2 ms. Ablation outcome was evaluated after 3, 6, 12 and 24 months with 12-lead ECGs and 24-hour Holter recordings. Twenty-five consecutive patients were included (58 ± 7 years, persistent AF duration 1.8 ± 0.9 years). Entrance block was achieved in all patients and exit block confirmed if sinus rhythm was achieved. After 17 ± 7 months, 76 % of the patients (n = 19) were free of AF recurrence. One patient died within 1 month and was considered an ablation failure. Four patients with AF recurrences regained sinus rhythm with additional catheter ablation or antiarrhythmic drugs. Treatment of longstanding persistent AF with thoracoscopic epicardial LA posterior box isolation using bipolar RF energy with intraoperative testing of conduction block is feasible and highly effective.

Heart rate and outcomes in patients with heart failure with preserved ejection fraction: A dose-response meta-analysis.

PubMed

Shang, Xiaoke; Lu, Rong; Liu, Mei; Xiao, Shuna; Dong, Nianguo

2017-10-01

Although elevated resting heart rate is related to poor outcomes in heart failure (HF) with reduced ejection fraction, the association in HF with preserved ejection fraction (HFpEF) remains inconclusive. Therefore, we conducted a dose-response meta-analysis to examine the prognostic role of heart rate in patients with HFpEF.We searched PubMed and Embase databases until April 2017 and manually reviewed the reference lists of relevant literatures. Random effect models were used to pool the study-specific hazard ratio (HR) of outcomes, including all-cause death, cardiovascular death, and HF hospitalization.Six studies with 7 reports were finally included, totaling 14,054 patients with HFpEF. The summary HR (95% confidence interval [CI]) for every 10 beats/minute increment in heart rate was 1.04 (1.02-1.06) for all-cause death, 1.06 (1.02-1.10) for cardiovascular death, and 1.05 (1.01-1.08) for HF hospitalization. Subgroup analyses indicated that these positive relationships were significant in patients with sinus rhythm but not in those with atrial fibrillation. There was also evidence for nonlinear relationship of heart rate with each of the outcomes (All P for nonlinearity < .05).Higher heart rate in sinus rhythm is a risk factor for adverse outcomes in patients with HFpEF. Future trials are required to determine whether heart rate reduction may improve the prognosis of HFpEF.

Left atrial structure and function in atrial fibrillation: ENGAGE AF-TIMI 48

PubMed Central

Gupta, Deepak K.; Shah, Amil M.; Giugliano, Robert P.; Ruff, Christian T.; Antman, Elliott M.; Grip, Laura T.; Deenadayalu, Naveen; Hoffman, Elaine; Patel, Indravadan; Shi, Minggao; Mercuri, Michele; Mitrovic, Veselin; Braunwald, Eugene; Solomon, Scott D.

2014-01-01

Aims The complex relationship between left atrial (LA) structure and function, electrical burden of atrial fibrillation (AF) and stroke risk is not well understood. We aimed to describe LA structure and function in AF. Methods and results Left atrial structure and function was assessed in 971 subjects enrolled in the echocardiographic substudy of ENGAGE AF-TIMI 48. Left atrial size, emptying fraction (LAEF), and contractile function were compared across AF types (paroxysmal, persistent, or permanent) and CHADS2 scores as an estimate of stroke risk. The majority of AF patients (55%) had both LA enlargement and reduced LAEF, with an inverse relationship between LA size and LAEF (R = −0.57, P < 0.001). With an increasing electrical burden of AF and higher CHADS2 scores, LA size increased and LAEF declined. Moreover, 19% of AF subjects had impaired LAEF despite normal LA size, and LA contractile dysfunction was present even among the subset of AF subjects in sinus rhythm at the time of echocardiography. Conclusions In a contemporary AF population, LA structure and function were increasingly abnormal with a greater electrical burden of AF and higher stroke risk estimated by the CHADS2 score. Moreover, LA dysfunction was present despite normal LA size and sinus rhythm, suggesting that the assessment of LA function may add important incremental information in the evaluation of AF patients. Clinical Trial Registration: http://www.clinicaltrials.gov; ID = NCT00781391. PMID:24302269

Optimal electrocardiographic limb lead set for rapid emphysema screening

PubMed Central

Bajaj, Rishi; Chhabra, Lovely; Basheer, Zainab; Spodick, David H

2013-01-01

Background Pulmonary emphysema of any etiology has been shown to be strongly and quasidiagnostically associated with a vertical frontal P wave axis. A vertical P wave axis (>60 degrees) during sinus rhythm can be easily determined by a P wave in lead III greater than the P wave in lead I (bipolar lead set) or a dominantly negative P wave in aVL (unipolar lead set). The purpose of this investigation was to determine which set of limb leads may be better for identifying the vertical P vector of emphysema in adults. Methods Unselected consecutive electrocardiograms from 100 patients with a diagnosis of emphysema were analyzed to determine the P wave axis. Patients aged younger than 45 years, those not in sinus rhythm, and those with poor quality tracings were excluded. The electrocardiographic data were divided into three categories depending on the frontal P wave axis, ie, >60 degrees, 60 degrees, or <60 degrees, by each criterion (P amplitude lead III > lead I and a negative P wave in aVL). Results Sixty-six percent of patients had a P wave axis > 60 degrees based on aVL, and 88% of patients had a P wave axis > 60 degrees based on the P wave in lead III being greater than in lead I. Conclusion A P wave in lead III greater than that in lead I is a more sensitive marker than a negative P wave in aVL for diagnosing emphysema and is recommended for rapid routine screening. PMID:23378754

Early and simple detection of diastolic dysfunction during weaning from mechanical ventilation

PubMed Central

2012-01-01

Weaning from mechanical ventilation imposes additional work on the cardiovascular system and can provoke or unmask left ventricular diastolic dysfunction with consecutive pulmonary edema or systolic dysfunction with inadequate increase of cardiac output and unsuccessful weaning. Echocardiography, which is increasingly used for hemodynamic assessment of critically ill patients, allows differentiation between systolic and diastolic failure. For various reasons, transthoracic echocardiographic assessment was limited to patients with good echo visibility and to those with sinus rhythm without excessive tachycardia. In these patients, often selected after unsuccessful weaning, echocardiographic findings were predictive for weaning failure of cardiac origin. In some studies, patients with various degrees of systolic dysfunction were included, making evaluation of the diastolic dysfunction to the weaning failure even more difficult. The recent study by Moschietto and coworkers included unselected patients and used very simple diastolic variables for assessment of diastolic function. They also included patients with atrial fibrillation and repeated echocardiographic examination only 10 minutes after starting a spontaneous breathing trial. The main finding was that weaning failure was not associated with systolic dysfunction but with diastolic dysfunction. By measuring simple and robust parameters for detection of diastolic dysfunction, the study was able to predict weaning failure in patients with sinus rhythm and atrial fibrillation as early as 10 minutes after beginning a spontaneous breathing trial. Further studies are necessary to determine whether appropriate treatment tailored according to the echocardiographic findings will result in successful weaning. PMID:22770365

Early and simple detection of diastolic dysfunction during weaning from mechanical ventilation.

PubMed

Voga, Gorazd

2012-07-06

Weaning from mechanical ventilation imposes additional work on the cardiovascular system and can provoke or unmask left ventricular diastolic dysfunction with consecutive pulmonary edema or systolic dysfunction with inadequate increase of cardiac output and unsuccessful weaning. Echocardiography, which is increasingly used for hemodynamic assessment of critically ill patients, allows differentiation between systolic and diastolic failure. For various reasons, transthoracic echocardiographic assessment was limited to patients with good echo visibility and to those with sinus rhythm without excessive tachycardia. In these patients, often selected after unsuccessful weaning, echocardiographic findings were predictive for weaning failure of cardiac origin. In some studies, patients with various degrees of systolic dysfunction were included, making evaluation of the diastolic dysfunction to the weaning failure even more difficult. The recent study by Moschietto and coworkers included unselected patients and used very simple diastolic variables for assessment of diastolic function. They also included patients with atrial fibrillation and repeated echocardiographic examination only 10 minutes after starting a spontaneous breathing trial. The main finding was that weaning failure was not associated with systolic dysfunction but with diastolic dysfunction. By measuring simple and robust parameters for detection of diastolic dysfunction, the study was able to predict weaning failure in patients with sinus rhythm and atrial fibrillation as early as 10 minutes after beginning a spontaneous breathing trial. Further studies are necessary to determine whether appropriate treatment tailored according to the echocardiographic findings will result in successful weaning.

Safety and efficacy of Cardi-O-fix occluder for percutaneous closure of a patent foramen ovale

PubMed Central

Zhao, Enfa; Liu, Wenjuan; Zhang, Yushun; Cheng, Gesheng; Du, Yajuan; He, Lu; Wang, Xingye; He, Xumei

2017-01-01

Abstract Background: Amplatzer occluder and Cardio-O-fix occluder are currently used in percutaneous closure of patent foramen ovale. However, there is still a lack of relevant reports comparison the differences between them. The aim of this study was to evaluate the short-term and mid-term safety and efficacy of the Cardi-O-fix occluder in preventing recurrent cerebrovascular events in patients with a patent foramen ovale (PFO). Methods: We enrolled 246 patients (105 men) with a PFO from May 30, 2013 to March 30, 2015 in this single-center prospective study. All patients were treated by PFO interventional closure, with the Cardi-O-fix PFO occluder being used in 180 patients and the Amplatzer PFO occluder being utilized in the remaining 66 patients. After the procedure, we verified the safety and efficacy of different devices using contrast transthoracic echocardiography. Results: Neither recurrent stroke nor death was encountered during the follow-up of 12 months. Transient ischemic attack (TIA) was noted in 2 patients (1.1%) in the Cardi-O-fix PFO occluder group, and 1 patient suffered from TIA (1.5%) in the Amplatzer PFO occluder group. Among them, only 1 patient exhibited a small right to left shunt (RLS). There was no statistical difference in recurrent cerebral ischemic events. Three cases of paroxysmal atrial fibrillation were observed in the Cardi-O-fix PFO occluder group. One reverted spontaneously to sinus rhythm and the other 2 cases had pharmacologic conversion to sinus rhythm. One case of paroxysmal atrial fibrillation occurred in the Amplatzer group, which underwent pharmacologic conversion to sinus rhythm. There was no significant difference between the 2 groups regarding incidence of arrhythmia. No occluder translocation, erosion, pericardial effusion, and puncture site bleeding were observed in the 2 groups within 12 months of follow-up. The complete closure rates of the Cardi-O-fix and Amplatzer PFO occluder devices at the 12 months after the procedure were 73.9% and 63.6%, respectively, and the effective closure rates were 90.6% and 86.4%, respectively. There was no statistically significant difference in the complete closure rate and effective occlusion rate (P > 0.05) between the devices. Conclusions: There was no significant difference in the short- and mid-term efficacy and safety between the Cardi-O-fix PFO occluder and Amplatzer PFO occluder. The efficacy and safety of the Cardi-O-fix occluder were comparable to those of the Amplatzer PFO occluder. PMID:28383438

Stroke in Heart Failure in Sinus Rhythm: The Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction Trial

PubMed Central

Pullicino, Patrick M.; Thompson, John L.P.; Sacco, Ralph L.; Sanford, Alexandra R.; Qian, Min; Teerlink, John R.; Haddad, Haissam; Diek, Monika; Freudenberger, Ronald S.; Labovitz, Arthur J.; Di Tullio, Marco R.; Lok, Dirk J.; Ponikowski, Piotr; Anker, Stefan D.; Graham, Susan; Mann, Douglas L.; Mohr, J.P.; Homma, Shunichi

2014-01-01

Background The Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction trial found no difference between warfarin and aspirin in patients with low ejection fraction in sinus rhythm for the primary outcome: first to occur of 84 incident ischemic strokes (IIS), 7 intracerebral hemorrhages or 531 deaths. Prespecified secondary analysis showed a 48% hazard ratio reduction (p = 0.005) for warfarin in IIS. Cardioembolism is likely the main pathogenesis of stroke in heart failure. We examined the IIS benefit for warfarin in more detail in post hoc secondary analyses. Methods We subtyped IIS into definite, possible and noncardioembolic using the Stroke Prevention in Atrial Fibrillation method. Statistical tests, stratified by prior ischemic stroke or transient ischemic attack, were the conditional binomial for independent Poisson variables for rates, the Cochran-Mantel-Haenszel test for stroke subtype and the van Elteren test for modified Rankin Score (mRS) and National Institute of Health Stroke Scale (NIHSS) distributions, and an exact test for proportions. Results Twenty-nine of 1,142 warfarin and 55 of 1,163 aspirin patients had IIS. The warfarin IIS rate (0.727/100 patient-years, PY) was lower than for aspirin (1.36/100 PY, p = 0.003). Definite cardioembolic IIS was less frequent on warfarin than aspirin (0.22 vs. 0.55/100 PY, p = 0.012). Possible cardioembolic IIS tended to be less frequent on warfarin than aspirin (0.37 vs. 0.67/100 PY, p = 0.063) but noncardioembolic IIS showed no difference: 5 (0.12/100 PY) versus 6 (0.15/100 PY, p = 0.768). Among patients experiencing IIS, there were no differences by treatment arm in fatal IIS, baseline mRS, mRS 90 days after IIS, and change from baseline to post-IIS mRS. The warfarin arm showed a trend to a lower proportion of severe nonfatal IIS [mRS 3–5; 3/23 (13.0%) vs. 16/48 (33.3%), p = 0.086]. There was no difference in NIHSS at the time of stroke (p = 0.825) or in post-IIS mRS (p = 0.948) between cardioembolic, possible cardioembolic and noncardioembolic stroke including both warfarin and aspirin groups. Conclusions The observed benefits in the reduction of IIS for warfarin compared to aspirin are most significant for cardioembolic IIS among patients with low ejection fraction in sinus rhythm. This is supported by trends to lower frequencies of severe IIS and possible cardioembolic IIS in patients on warfarin compared to aspirin. PMID:23921215

Stroke in heart failure in sinus rhythm: the Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction trial.

PubMed

Pullicino, Patrick M; Thompson, John L P; Sacco, Ralph L; Sanford, Alexandra R; Qian, Min; Teerlink, John R; Haddad, Haissam; Diek, Monika; Freudenberger, Ronald S; Labovitz, Arthur J; Di Tullio, Marco R; Lok, Dirk J; Ponikowski, Piotr; Anker, Stefan D; Graham, Susan; Mann, Douglas L; Mohr, J P; Homma, Shunichi

2013-01-01

The Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction trial found no difference between warfarin and aspirin in patients with low ejection fraction in sinus rhythm for the primary outcome: first to occur of 84 incident ischemic strokes (IIS), 7 intracerebral hemorrhages or 531 deaths. Prespecified secondary analysis showed a 48% hazard ratio reduction (p = 0.005) for warfarin in IIS. Cardioembolism is likely the main pathogenesis of stroke in heart failure. We examined the IIS benefit for warfarin in more detail in post hoc secondary analyses. We subtyped IIS into definite, possible and noncardioembolic using the Stroke Prevention in Atrial Fibrillation method. Statistical tests, stratified by prior ischemic stroke or transient ischemic attack, were the conditional binomial for independent Poisson variables for rates, the Cochran-Mantel-Haenszel test for stroke subtype and the van Elteren test for modified Rankin Score (mRS) and National Institute of Health Stroke Scale (NIHSS) distributions, and an exact test for proportions. Twenty-nine of 1,142 warfarin and 55 of 1,163 aspirin patients had IIS. The warfarin IIS rate (0.727/100 patient-years, PY) was lower than for aspirin (1.36/100 PY, p = 0.003). Definite cardioembolic IIS was less frequent on warfarin than aspirin (0.22 vs. 0.55/100 PY, p = 0.012). Possible cardioembolic IIS tended to be less frequent on warfarin than aspirin (0.37 vs. 0.67/100 PY, p = 0.063) but noncardioembolic IIS showed no difference: 5 (0.12/100 PY) versus 6 (0.15/100 PY, p = 0.768). Among patients experiencing IIS, there were no differences by treatment arm in fatal IIS, baseline mRS, mRS 90 days after IIS, and change from baseline to post-IIS mRS. The warfarin arm showed a trend to a lower proportion of severe nonfatal IIS [mRS 3-5; 3/23 (13.0%) vs. 16/48 (33.3%), p = 0.086]. There was no difference in NIHSS at the time of stroke (p = 0.825) or in post-IIS mRS (p = 0.948) between cardioembolic, possible cardioembolic and noncardioembolic stroke including both warfarin and aspirin groups. The observed benefits in the reduction of IIS for warfarin compared to aspirin are most significant for cardioembolic IIS among patients with low ejection fraction in sinus rhythm. This is supported by trends to lower frequencies of severe IIS and possible cardioembolic IIS in patients on warfarin compared to aspirin. Copyright © 2013 S. Karger AG, Basel.

Evaluation of heart rhythm variability and arrhythmia in children with systemic and localized scleroderma.

PubMed

Wozniak, Jacek; Dabrowski, Rafal; Luczak, Dariusz; Kwiatkowska, Malgorzata; Musiej-Nowakowska, Elzbieta; Kowalik, Ilona; Szwed, Hanna

2009-01-01

To evaluate possible disturbances in autonomic regulation and cardiac arrhythmias in children with localized and systemic scleroderma. There were 40 children included in the study: 20 with systemic and 20 with localized scleroderma. The control group comprised 20 healthy children. In 24-hour Holter recording, the average rate of sinus rhythm was significantly higher in the groups with systemic and localized scleroderma than in the control group, but there was no significant difference between them. The variability of heart rhythm in both groups was significantly decreased. In the group with systemic scleroderma, single supraventricular ectopic beats were observed in 20% and runs were seen in 40% of patients. In the group with localized scleroderma, supraventricular single ectopic beats occurred in 35% of patients and runs in 45% of those studied. Ventricular arrhythmia occurred in 2 children with systemic scleroderma, but in 1 child, it was complex. The most frequent cardiac arrhythmias in both types of scleroderma in children were of supraventricular origin, whereas ventricular arrhythmias did not occur very often. There were no significant differences in autonomic disturbances manifesting as a higher heart rate and decreased heart rate variability between localized and systemic scleroderma.

Dronedarone: a promising alternative for the management of atrial fibrillation.

PubMed

Yalta, Kenan; Turgut, Okan Onur; Yilmaz, Mehmet Birhan; Yilmaz, Ahmet; Tandogan, Izzet

2009-10-01

Atrial fibrillation (AF) is the most frequently encountered chronic arrhythmia associated with significant morbidity. It is generally encountered in the elderly, and will presumably become more prevalent in the future due to the increasing proportion of the elderly in the population. Major studies on AF have demonstrated no significant difference between rhythm and rate control in terms of mortality. However, young population with new-onset or lone AF, or patients in whom the maintenance of sinus rhythm is a must (due to recurrent thromboembolic events etc.) still gives rise to significant concerns related to the obligatory long-term prophylaxis. The long-term administration of the currently available conventional agents (amiodarone, dofetilide, sotalol, propafenone,flecainide etc.) is considered as a 'double edged sword' due to the presence of life-threatening adverse effects including pro-arrhythmia and organ toxicity associated with these agents. Several molecules are being developed for the management of AF. However, only a few novel agents confer promising results with respect to safety and efficacy issues in the major studies. Dronedarone is an amiodarone analogue without iodine moiety in its structure, and is similar to amiodarone with regard to its structural and electrophysiological properties. Dronedarone is largely denuded of the potentially life-threatening adverse effects of anti-arrhythmics. Major clinical studies have demonstrated both rhythm and rate-controlling efficacy of dronedarone compared to placebo without any serious adverse effects in patients with AF. However, the ANDROMEDA trial, a large scale study including patients hospitalized for symptomatic congestive heart failure (with severely depressed left ventricular systolic functions) was prematurely terminated due to the increased mortality in the dronedarone arm compared to placebo indicating a lack of safety in this group of patients. Conversely, the recently published ATHENA study (including more than 4,600 high risk patients, but excluding those with severe heart failure) demonstrated a significant reduction in cardiovascular hospitalizations and cardiovascular mortality with dronedarone compared to placebo. In contrast, the DIONYSOS study, comparing dronedarone with amiodarone, demonstrated better safety, but lower efficacy of dronedarone for the maintenance of sinus rhythm in patients with AF. Further clinical trials (including head to head comparison with other conventional anti-arrhythmics) are still required to determine the place of dronedarone in the management of AF. The present review focuses on basic and clinical aspects of dronedarone, a novel agent for the management of AF.

[Cardioversion for paroxysmal supraventricular tachycardia during lung surgery in a patient with concealed Wolff-Parkinson-White syndrome].

PubMed

Sato, Yoshiharu; Nagata, Hirofumi; Inoda, Ayako; Miura, Hiroko; Watanabe, Yoko; Suzuki, Kenji

2014-10-01

We report a case of paroxysmal supraventricular tachycardia (PSVT) that occurred during video-assisted thoracoscopic (VATS) lobectomy in a patient with concealed Wolff-Parkinson-White (WPW) syndrome. A 59-year-old man with lung cancer was scheduled for VATS lobectomy under general anesthesia. After inserting a thoracic epidural catheter, general anesthesia was induced with intravenous administration of propofol. Anesthesia was maintained with inhalation of desfurane in an air/oxygen mixture and intravenous infusion of remifentanil. Recurrent PSVT occurred three times, and the last episode of PSVT continued for 50 minutes regardless of administration of antiarrhythmic drugs. Synchronized electric shock via adhesive electrode pads on the patient's chest successfully converted PSVT back to normal sinus rhythm. The remaining course and postoperative period were uneventful. An electrophysiological study performed after hospital discharge detected concealed WPW syndrome, which had contributed to the development of atrioventricular reciprocating tachycardia. Concealed WPW syndrome is a rare, but critical complication that could possibly cause lethal atrial tachyarrhythmias during the perioperative period. In the present case, cardioversion using adhesive electrode pads briefly terminated PSVT in a patient with concealed WPW syndrome.

The teenager with palpitations.

PubMed

Sedaghat-Yazdi, Farshad; Koenig, Peter R

2014-02-01

Palpitations can result from cardiac awareness (increased conscious perception of the heart beating) or from a fast or irregular cardiac rhythm. Most causes for palpitations in the teenager can be diagnosed with minimal testing. Patients with an abnormal ECG, non-sinus tachycardia, abnormal cardiac examination, concerning family history, or palpitations associated with activity or syncope should be referred to a pediatric cardiologist. This article discusses the evaluation, testing, and management of teenagers with palpitations. It also provides a general guideline for referral for subspecialty evaluation. Copyright © 2014 Elsevier Inc. All rights reserved.

Atrial fibrillation in a pregnant mare: treatment with quinidine sulfate.

PubMed

Bertone, J J; Traub-Dargatz, J L; Wingfield, W E

1987-06-15

Atrial fibrillation in a pregnant, lactating, 15-year-old mare nursing a 70-day-old foal was converted to normal sinus rhythm, using quinidine sulfate. The maximum concentration of quinidine was 4.3 mg/L in the mare's milk and was 2.6 mg/L in the mare's serum. Treatment with quinidine did not interrupt the pregnancy. Six months after treatment, the mare developed acute volvulus of the large colon and died. At necropsy, the mare did not have macroscopic or microscopic cardiac lesions. The fetus was macroscopically and histologically normal.

A flash from the past: a case on long term follow-up of a "corridor" operation.

PubMed

Ricciardi, Danilo; Sarkozy, Andrea; Wauters, Kristel; Brugada, Pedro

2013-01-01

An electrophysiological study in a patient with a previous corridor operation was performed because of syncope. The atrial electrograms showed the persistence of the sinus rhythm in the right atrial corridor despite an organized atrial fibrillation in the left atrium. The first case described of a long term follow-up in a corridor operation, one of the first described surgical approach for the treatment of atrial fibrillation, that gave the beginning to the non-pharmacological approach of this arrhythmia. Copyright © 2013 Elsevier Inc. All rights reserved.

An introduction to the reading of electrocardiograms.

PubMed

Woodrow, P

This article introduces the basic principles of reading electrocardiograms (ECGs) for nurses who are unfamiliar with reading them. For more experienced practitioners there are a number of useful articles and books (e.g. Hampton, 1992a, b) that will help further their knowledge. The ECG records cardiac electrical activity as a graph; interpretation is illustrated here by sinus rhythm. A single ECG lead (lead II) is used throughout this article. Atrial fibrillation is described to show a contrasting dysrhythmia. Specific nursing care is suggested for patients being monitored or having ECGs taken.

Atrial fibrillation in the elderly

PubMed Central

Franken, Roberto A.; Rosa, Ronaldo F.; Santos, Silvio CM

2012-01-01

This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted. PMID:22916053

Pacemaker failure associated with therapeutic radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, C.; Mutter, M.

1988-11-01

A 48-year-old white man with a multiprogrammable Intramedics 259-01 pacemaker was treated for inoperable lung cancer with a course of cobalt-60 radiotherapy (total 3500 rad). Several weeks subsequent to his last radiation treatment, the patient presented to the emergency department with chest and abdominal pain, shortness of breath, hypotension, and tachycardia. A paced tachycardia was noted, and application of a magnet over the pacemaker completely inhibited its function, allowing a normal sinus rhythm to ensue and the patient's symptoms to be relieved. Pacemaker failure probably was a complication of radiotherapy.

'In a dark place, we find ourselves': light intensity in critical care units.

PubMed

Durrington, Hannah J; Clark, Richard; Greer, Ruari; Martial, Franck P; Blaikley, John; Dark, Paul; Lucas, Robert J; Ray, David W

2017-12-01

Intensive care units provide specialised care for critically ill patients around the clock. However, intensive care unit patients have disrupted circadian rhythms. Furthermore, disrupted circadian rhythms are associated with worse outcome. As light is the most powerful 're-setter' of circadian rhythm, we measured light intensity on intensive care unit. Light intensity was low compared to daylight during the 'day'; frequent bright light interruptions occurred over 'night'. These findings are predicted to disrupt circadian rhythms and impair entrainment to external time. Bright lighting during daytime and black out masks at night might help maintain biological rhythms in critically ill patients and improve clinical outcomes.

Maxillary Sinus Augmentation for Dental Implant Rehabilitation of the Edentulous Ridge: A Comprehensive Overview of Systematic Reviews.

PubMed

Ting, Miriam; Rice, Jeremy G; Braid, Stanton M; Lee, Cameron Y S; Suzuki, Jon B

2017-06-01

The objective of this systemic review was to perform a comprehensive overview of systematic reviews and meta-analyses of the maxillary sinus augmentation procedure for implant rehabilitation in humans. The following were evaluated in this overview: (1) anatomic variables affecting sinus augmentation, (2) histomorphometric analysis of the grafted sinus, (3) volumetric changes after sinus grafting, and (4) implant survival beyond 1 year. Electronic databases were searched for systematic reviews and meta-analyses of implant-related sinus augmentation published from 1976 to September 2015. The studies selected must identify itself as a systemic review or meta-analysis in the title or abstract and must pertain to sinus augmentation. Thirty-three publications fulfilled the review criteria. The AMSTAR ratings for the 33 chosen reviews scored greater than 3 of 11, with 8 reviews scoring greater or equal to 8 of 11. The outcome of this overview suggested that the following will increase the success of sinus augmentation and survival of implants placed in the grafted sinus: (1) the use of barrier membranes over the lateral window when using a lateral approach to graft the sinus, (2) the use of particulate autogenous bone with or without other substitute graft materials, (3) sinus augmentation without the use of grafting materials may be considered provided that the space between the sinus membrane and floor can be maintained, (4) the use of rough-surfaced implants, (5) simultaneous implant placement with residual bone height greater than 4 mm, and (6) the cessation of smoking.

[Intervention among patients with right bundle branch block and left anterior hemiblock. Operatory risk (author's transl)].

PubMed

Coriat, P; Harari, A; Tarot, J P; Ducardonnet, A; Viars, P

1981-01-01

In order to assess the risk of advanced heart block during anesthesia in patients with right bundle branch block and left anterior hemiblock, 35 consecutive patients were monitored throughout the pre-, intra- and postoperative period. As conventional ECG monitoring may only detect advanced atrioventricular block, patients were monitored according to the Holter method which can easily detect even minor changes of atrioventricular conduction namely slight increased PR interval or dropped P wave. All patients were asymptomatic, in normal sinus rhythm without second degree AV block. Surgical procedures were performed under general anesthesia (n = 15) and epidural anesthesia using lidocaine (n = 20). No episode of second or third degree atrioventricular block occurred. The only modifications observed were rare and transient increase of PR, occurring during surgical procedures in 5 patients, always associated with a sinus bradycardia. They immediately regressed at the termination of the sinus bradycardia either spontaneously or following atropine injection, strongly suggesting the responsability of increased vagal tone. Thus general or epidural anesthesia did not compromise infranodal conduction in any of the observed patients. These data indicate that anesthesia can be safely used without prophylactic preoperative insertion of pacemakers in patients with asymptomatic chronic right bundle branch block and left anterior hemi-block.

The sinonasal communication in the horse: examinations using computerized three-dimensional reformatted renderings of computed-tomography datasets

PubMed Central

2014-01-01

Background Sinusitis is a common disease in the horse. In human medicine it is described, that obstruction of the sinonasal communication plays a major role in the development of sinusitis. To get spatial sense of the equine specific communication ways between the nasal cavity and the paranasal sinuses, heads of 19 horses, aged 2 to 26 years, were analyzed using three-dimensional (3D) reformatted renderings of CT-datasets. Three-dimensional models were generated following manual and semi-automated segmentation. Before segmentation, the two-dimensional (2D) CT-images were verified against corresponding frozen sections of cadaveric heads. Results Three-dimensional analysis of the paranasal sinuses showed the bilateral existence of seven sinus compartments: rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, frontal sinus, sphenopalatine sinus and middle conchal sinus. The maxillary septum divides these seven compartments into two sinus systems: a rostral paranasal sinus system composed of the rostral maxillary sinus and the ventral conchal sinus and a caudal paranasal sinus system which comprises all other sinuses. The generated 3D models revealed a typically configuration of the sinonasal communication ways. The sinonasal communication started within the middle nasal meatus at the nasomaxillary aperture (Apertura nasomaxillaris), which opens in a common sinonasal channel (Canalis sinunasalis communis). This common sinonasal channel ramifies into a rostral sinonasal channel (Canalis sinunasalis rostralis) and a caudo-lateral sinonasal channel (Canalis sinunasalis caudalis). The rostral sinonasal channel ventilated the rostral paranasal sinus system, the caudo-lateral sinonasal channel opened into the caudal paranasal sinus system. The rostral sinonasal channel was connected to the rostral paranasal sinuses in various ways. Whereas, the caudal channel showed less anatomical variations and was in all cases connected to the caudal maxillary sinus. Volumetric measurements of the sinonasal channels showed no statistically significant differences (P <0.05) between the right and left side of the head. Conclusions Under physiologic conditions both paranasal sinus systems are connected to the nasal cavity by equine specific sinonasal channels. To resolve sinus disease it is aimed to maintain or even reconstruct the normal anatomy of the sinonasal communication by surgical intervention. Therefore, the presented 3D analyses may provide a useful basis. PMID:24646003

Improvement of the myocardial performance index in atrial fibrilation patients treated with amiodarone after cardioversion.

PubMed

Besli, Feyzullah; Basar, Cengiz; Kecebas, Mesut; Turker, Yasin

2015-03-01

This study evaluated the response to electrical cardioversion (EC) and the effect on the myocardial performance index (MPI) in patients with persistent and long-standing persistent atrial fibrillation (AF). We enrolled 103 patients (mean age 69.6 ± 8.9 years, 40.7% males) with a diagnosis of persistent and long-standing persistent AF. EC was applied to all patients after one g of amiodarone administration. Echocardiographic findings before EC were compared in patients with successful versus unsuccessful cardioversions and in patients with maintained sinus rhythm (SR) versus those with AF recurrence at the end of the first month. We also compared echocardiographic data before EC versus at the end of the first month in the same patients with maintained SR. SR was achieved in 72.8% of patients and was continued at the end of the first month in 69.3% of the patients. The MPI value of all patients was found to be 0.73 ± 0.21. The size of the left atrium was determined to be an independent predictor of the maintenance of SR at 1 month. In subgroup analyses, when we compared echocardiographic findings before EC and at the end of the first month in patients with maintained SR, the MPI (0.66 ± 0.14 vs 0.56 ± 0.09, p < 0.001) values were significantly decreased. Our study is the first to show impairment of the MPI, which is an indicator of systolic and diastolic function, in patients with persistent and long-standing persistent AF and improvement of the MPI after successful EC.

Neurohumoral indicators of efficacy radiofrequency cardiac denervation

NASA Astrophysics Data System (ADS)

Evtushenko, A. V.; Evtushenko, V. V.; Saushkina, Yu. V.; Lishmanov, Yu. B.; Pokushalov, E. A.; Sergeevichev, D. S.; Gusakova, A. M.; Suslova, T. E.; Dymbrylova, O. N.; Bykov, A. N.; Syryamkin, V. I.; Kistenev, Yu. V.; Anfinogenova, Ya. D.; Smyshlyaev, K. A.; Lotkov, A. I.; Kurlov, I. O.

2015-11-01

In this study, we compared pre- and postoperative parameters of the cardiac sympathetic innervation. The aim of the study was to examine the approaches to evaluating the quality of radiofrequency (RF)-induced cardiac denervation by using non-invasive and laboratory methods. The study included 32 people with long-lasting persistent atrial fibrillation (AF). The patients were divided into 2 groups according to the objectives of the study: group 1 (main) - 21 patients with mitral valve diseases, which simultaneously with radiofrequency ablation (RFA) AF carried out on the effects of the paraganglionic nervous plexuses by C. Pappone (2004) and N. Doll (2008) schemes. The second group (control) contained 11 patients with heart diseases in sinus rhythm (the RF denervation not been performed). All patients, who underwent surgical treatment, were received examination of cardiac sympathetic tone by using 123I-MIBG. All of them made blood analysis from ascending aorta and coronary sinus to determine the level of norepinephrine and its metabolites before and after cardiac denervation. Data of radionuclide examination are correlating with laboratory data.

Dim nighttime illumination interacts with parametric effects of bright light to increase the stability of circadian rhythm bifurcation in hamsters.

PubMed

Evans, Jennifer A; Elliott, Jeffrey A; Gorman, Michael R

2011-07-01

The endogenous circadian pacemaker of mammals is synchronized to the environmental day by the ambient cycle of relative light and dark. The present studies assessed the actions of light in a novel circadian entrainment paradigm where activity rhythms are bifurcated following exposure to a 24-h light:dark:light:dark (LDLD) cycle. Bifurcated entrainment under LDLD reflects the temporal dissociation of component oscillators that comprise the circadian system and is facilitated when daily scotophases are dimly lit rather than completely dark. Although bifurcation can be stably maintained in LDLD, it is quickly reversed under constant conditions. Here the authors examine whether dim scotophase illumination acts to maintain bifurcated entrainment under LDLD through potential interactions with the parametric actions of bright light during the two daily photophases. In three experiments, wheel-running rhythms of Syrian hamsters were bifurcated under LDLD with dimly lit scotophases, and after several weeks, dim scotophase illumination was either retained or extinguished. Additionally, "full" and "skeleton" photophases were employed under LDLD cycles with dimly lit or completely dark scotophases to distinguish parametric from nonparametric effects of bright light. Rhythm bifurcation was more stable in full versus skeleton LDLD cycles. Dim light facilitated the maintenance of bifurcated entrainment under full LDLD cycles but did not prevent the loss of rhythm bifurcation in skeleton LDLD cycles. These studies indicate that parametric actions of bright light maintain the bifurcated entrainment state; that dim scotophase illumination increases the stability of the bifurcated state; and that dim light interacts with the parametric effects of bright light to increase the stability of rhythm bifurcation under full LDLD cycles. A further understanding of the novel actions of dim light may lead to new strategies for understanding, preventing, and treating chronobiological disturbances.

Assessment of atrial electromechanical interval using echocardiography after catheter ablation in patients with persistent atrial fibrillation

PubMed Central

Chen, Xiaodong; Chen, Minglong; Wang, Yingying; Yang, Bing; Ju, Weizhu; Zhang, Fengxiang; Cao, Kejiang

2016-01-01

Abstract We sought to investigate variation of atrial electromechanical interval after catheter ablation procedure in patients with persistent atrial fibrillation using pulse Doppler (PW) and pulse tissue Doppler imaging (PW-TDI). A total of 25 consecutive in-patients with persistent atrial fibrillation, who restored sinus rhythm after ablation procedure, were recruited in our cardiac center. Echocardiography was performed on each patient at 2 hours, 1 day, 5 days, 1 month and 3 months after the ablation therapy, and atrial electromechanical delay was measured simultaneously by PW and PW-TDI. There was no significant difference between PW and TDI in measuring atrial electromechanical delay. However, at postoperative 2 hours, peak A detection rates were mathematically but nonsignificantly greater by PW-TDI than by PW. Second, there was a significant decreasing trend in atrial electromechanical interval from postoperative 2 hours to 3 months, but only postoperative 2-hour atrial electromechanical interval was significantly greater than atrial electromechanical interval at other time. Lastly, patients without postoperative 2-hour atrial electromechanical interval had a significantly longer duration of atrial fibrillation as compared to those with postoperative 2-hour atrial electromechanical interval, by the PW or by PW-TDI, respectively. In patients with persistent atrial fibrillation, atrial electromechanical interval may decrease significantly within the first 24 hours after ablation but remain consistent later, and was significantly related to patients’ duration of atrial fibrillation. Atrial electromechanical interval, as a potential predicted factor, is recommended to be measured by either PW or TDI after 24 hours, when patients had recovered sinus rhythm by radiofrequency ablation. PMID:27924066

Reproducibility and Angle Independence of Electromechanical Wave Imaging for the Measurement of Electromechanical Activation during Sinus Rhythm in Healthy Humans.

PubMed

Melki, Lea; Costet, Alexandre; Konofagou, Elisa E

2017-10-01

Electromechanical wave imaging (EWI) is an ultrasound-based technique that can non-invasively map the transmural electromechanical activation in all four cardiac chambers in vivo. The objective of this study was to determine the reproducibility and angle independence of EWI for the assessment of electromechanical activation during normal sinus rhythm (NSR) in healthy humans. Acquisitions were performed transthoracically at 2000 frames/s on seven healthy human hearts in parasternal long-axis, apical four- and two-chamber views. EWI data was collected twice successively in each view in all subjects, while four successive acquisitions were obtained in one case. Activation maps were generated and compared (i) within the same acquisition across consecutive cardiac cycles; (ii) within same view across successive acquisitions; and (iii) within equivalent left-ventricular regions across different views. EWI was capable of characterizing electromechanical activation during NSR and of reliably obtaining similar patterns of activation. For consecutive heart cycles, the average 2-D correlation coefficient between the two isochrones across the seven subjects was 0.9893, with a mean average activation time fluctuation in LV wall segments across acquisitions of 6.19%. A mean activation time variability of 12% was obtained across different views with a measurement bias of only 3.2 ms. These findings indicate that EWI can map the electromechanical activation during NSR in human hearts in transthoracic echocardiography in vivo and results in reproducible and angle-independent activation maps. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Phase mapping of radionuclide gated biventriculograms in patients with sustained ventricular tachycardia or Wolff-Parkinson-White syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Guludec, D.; Bourguignon, M.; Sebag, C.

1987-01-01

Accuracy of Fourier phase mapping of radionuclide gated biventriculograms in detecting the origin of abnormal ventricular activation was studied during ventricular tachycardia or preexcitation. Group I included six patients suffering from clinical recurrent VT; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right ventricular pacing, and induced sustained VT-Group II included seven patients with Wolff-Parkinson-White syndrome and recurrent paroxysmal tachycardia; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right atrial pacing and orthodromic reciprocating tachycardia. Each acquisition lasted 5 min, in 30 degrees-40 degrees left anterior oblique projection. In Groupmore » I, the Fourier phase mapping was consistent with QRS morphology and axis during VT (5/6), except in one patient with LV aneurysm and LBBB electrical pattern during VT. Origin of VT on phase mapping was located in the right ventricle (n = 2) or in left ventricle (n = 4), at the border of wall motion abnormalities each time they existed (5/6). In Group II, the phase advance correlated with the location of the accessory pathway determined by ECG and endocardial mapping (n = 6) and per-operative epicardial mapping (n = 1). Discrimination between anterior and posterior localization of paraseptal pathways and location of intermittent preexcitation was not possible. We conclude that Fourier phase mapping is an accurate method for locating the origin of VT and determining its etiology. It can help locate the site of ventricular preexcitation in patients with only one accessory pathway; its accuracy in locating multiple accessory pathways remains unknown.« less

Cerebrovascular accidents in adult patients with congenital heart disease.

PubMed

Hoffmann, A; Chockalingam, P; Balint, O H; Dadashev, A; Dimopoulos, K; Engel, R; Schmid, M; Schwerzmann, M; Gatzoulis, M A; Mulder, B; Oechslin, E

2010-08-01

To investigate the prevalence and characteristics of cerebrovascular accidents (CVA) in a large population of adults with congenital heart disease (CHD). In a retrospective analysis of aggregated European and Canadian databases a total population of 23 153 patients with CHD was followed up to the age of 16-91 years (mean 36.4 years). Among them, 458 patients (2.0%) had one or more CVA, with an estimated event rate of 0.05% per patient-year. Permanent neurological sequelae were noted in 116 patients (25.3%). The prevalence of CVA in selected diagnostic categories was as follows: open atrial septal defect 93/2351 (4.0%); closed atrial or ventricular septal defect 57/4035 (1.4%); corrected tetralogy of Fallot 52/2196 (2.4%); Eisenmenger physiology 24/467 (5.1%); other cyanotic 50/215 (23.3%); mechanical prostheses (29/882 (3.3%). Associated conditions in patients with CVA were absence of sinus rhythm (25%), transvenous pacemakers (7%), endocarditis (2%), cardiac surgery (11%) and catheter intervention (2%), but with the exception of absent sinus rhythm these were not significantly more prevalent in patients with CVA. CVA are a major contributor to morbidity in this young population despite absence of classical cardiovascular risk factors. Although the prevalence of CVA in patients with CHD appears low, it is 10-100 times higher than expected in control populations of comparable age. Residua occur in a strong minority of patients. The subjects at highest risk are those patients with CHD with cyanotic lesions, in whom the prevalence is over 10-fold above the average.

Effects of septal pacing on P wave characteristics: the value of three-dimensional echocardiography.

PubMed

Szili-Torok, Tamas; Bruining, Nico; Scholten, Marcoen; Kimman, Geert-Jan; Roelandt, Jos; Jordaens, Luc

2003-01-01

Interatrial septum (IAS) pacing has been proposed for the prevention of paroxysmal atrial fibrillation. IAS pacing is usually guided by fluoroscopy and P wave analysis. The authors have developed a new approach for IAS pacing using intracardiac echocardiography (ICE), and examined its effects on P wave characteristics. Cross-sectional images are acquired during pullback of the ICE transducer from the superior vena cava into the inferior vena cava by an electrocardiogram- and respiration-gated technique. The right atrium and IAS are then three-dimensionally reconstructed, and the desired pacing site is selected. After lead placement and electrical testing, another three-dimensional reconstruction is performed to verify the final lead position. The study included 14 patients. IAS pacing was achieved at seven suprafossal (SF) and seven infrafossal (IF) lead locations, all confirmed by three-dimensional imaging. IAS pacing resulted in a significant reduction of P wave duration as compared to sinus rhythm (99.7 +/- 18.7 vs 140.4 +/- 8.8 ms; P < 0.01). SF pacing was associated with a greater reduction of P wave duration than IF pacing (56.1 +/- 9.9 vs 30.2 +/- 13.6 ms; P < 0.01). P wave dispersion remained unchanged during septal pacing as compared to sinus rhythm (21.4 +/- 16.1 vs 13.5 +/- 13.9 ms; NS). Three-dimensional intracardiac echocardiography can be used to guide IAS pacing. SF pacing was associated with a greater decrease in P wave duration, suggesting that it is a preferable location to decrease interatrial conduction delay.

[Left atrial electric isolation in the treatment of atrial fibrillation secondary to rheumatic valvular disease].

PubMed

Graffigna, A; Pagani, F; Minzioni, G; Salerno, J; Viganò, M

1992-08-01

Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent valve surgery. From May 1989 to September 1991, 62 patients underwent mitral valve surgery (Group I), 19 underwent mitral valve surgery and DeVega tricuspid annuloplasty (Group II), 15 underwent mitral and aortic surgery (Group III), and 4 patients underwent mitral and aortic surgery and DeVega tricuspid annuloplasty (Group IV). Left atrial isolation was performed prolonging the usual left paraseptal atriotomy towards the left fibrous trigone anteriorly, and the postero-medial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesion were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 cases (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (Group I: 80.7%; Group II: 68.5%; Group III 86.7%, Group IV 75% - p = N.S.). Three cases of late mortality (3.1%) were registered. long-term results showed persistence of SR in 71% of Group I, 61.2% of Group II, 85.8% of Group III, and 100% of Group IV. The unique risk factor for late recurrency of atrial fibrillation was found to be a duration of preoperative AF longer than 6 months. Due to the high success rate in recovering the sinus rhythm, we suggest left atrial isolation in patients with chronic atrial fibrillation undergoing valvular surgery.

Initial Experience With Ultra High-Density Mapping of Human Right Atria.

PubMed

Bollmann, Andreas; Hilbert, Sebastian; John, Silke; Kosiuk, Jedrzej; Hindricks, Gerhard

2016-02-01

Recently, an automatic, high-resolution mapping system has been presented to accurately and quickly identify right atrial geometry and activation patterns in animals, but human data are lacking. This study aims to assess the clinical feasibility and accuracy of high-density electroanatomical mapping of various RA arrhythmias. Electroanatomical maps of the RA (35 partial and 24 complete) were created in 23 patients using a novel mini-basket catheter with 64 electrodes and automatic electrogram annotation. Median acquisition time was 6:43 minutes (0:39-23:05 minutes) with shorter times for partial (4.03 ± 4.13 minutes) than for complete maps (9.41 ± 4.92 minutes). During mapping 3,236 (710-16,306) data points were automatically annotated without manual correction. Maps obtained during sinus rhythm created geometry consistent with CT imaging and demonstrated activation originating at the middle to superior crista terminalis, while maps during CS pacing showed right atrial activation beginning at the infero-septal region. Activation patterns were consistent with cavotricuspid isthmus-dependent atrial flutter (n = 4), complex reentry tachycardia (n = 1), or ectopic atrial tachycardia (n = 2). His bundle and fractionated potentials in the slow pathway region were automatically detected in all patients. Ablation of the cavotricuspid isthmus (n = 9), the atrio-ventricular node (n = 2), atrial ectopy (n = 2), and the slow pathway (n = 3) was successfully and safely performed. RA mapping with this automatic high-density mapping system is fast, feasible, and safe. It is possible to reproducibly identify propagation of atrial activation during sinus rhythm, various tachycardias, and also complex reentrant arrhythmias. © 2015 Wiley Periodicals, Inc.

Histopathological Study of Left and Right Atria in Isolated Rheumatic Mitral Stenosis With and Without Atrial Fibrillation.

PubMed

Shenthar, Jayaprakash; Kalpana, Saligrama Ramegowda; Prabhu, Mukund A; Rai, Maneesh K; Nagashetty, Ravikumar Kalyani; Kamlapurkar, Giridhar

2016-09-01

Mitral stenosis (MS) has the highest incidence of atrial fibrillation (AF) in chronic rheumatic valvular disease. There are very few studies in isolated MS comparing histopathological changes in patients with sinus rhythm (SR) and AF. To analyze the histological changes associated with isolated MS and compare between changes in AF and SR. This was a prospective study in patients undergoing valve replacement surgery for symptomatic isolated MS who were divided into 2 groups, Group I AF (n = 13) and Group II SR (n = 10). Intra-operative biopsies performed from 5 different sites from both atria were analyzed for 10 histopathologic changes commonly associated with AF. On multivariate analysis, myocytolysis (odds ratio [OR]: 1.48, P = 0.05) was found to be associated with AF, whereas myocyte hypertrophy (OR: 0.21, P = 0.003), and glycogen deposition (OR: 0.43, P = 0.002) was associated with SR. Interstitial fibrosis the commonest change was uniformly distributed across both atria irrespective of the rhythm. In rheumatic MS, SR is associated with myocyte hypertrophy whereas AF is associated with myocytolysis. Endocardial inflammation is more common in left atrial appendage irrespective of rhythm. Interstitial fibrosis is seen in >90% of patients distributed in both the atria and is independent of the rhythm. Amyloid and Aschoff bodies are uncommon and the rest of the changes are uniformly distributed across both the atria. © 2016 Wiley Periodicals, Inc.

Activity in the ferret: oestradiol effects and circadian rhythms

NASA Technical Reports Server (NTRS)

Stockman, E. R.; Albers, H. E.; Baum, M. J.; Wurtman, R. J. (Principal Investigator)

1985-01-01

The present study was conducted to determine whether oestradiol increases activity in the European ferret (Mustela furo), whether this effect is sexually dimorphic, and whether a 24-h rhythm is present in the ferret's daily activity. The activity of male and female adult, postpubertally gonadectomized ferrets was monitored while they were maintained singly on a 13:11 light-dark cycle, before and after implantation with oestradiol-17 beta. Gonadectomized male and female ferrets exhibited equal levels of activity, and neither sex exhibited a significant change in activity following oestradiol implantation. None of the ferrets exhibited a strong circadian rhythm, although weak 24-h rhythms and shorter harmonic rhythms were present. Golden hamsters (Mesocricetus auratus), monitored in an identical manner, exhibited strong circadian rhythms. It was concluded that oestradiol administration may not cause an increase in activity in the ferret, and that this species lacks a strong circadian activity rhythm.

Atrial rhythm influences catheter tissue contact during radiofrequency catheter ablation of atrial fibrillation: comparison of contact force between sinus rhythm and atrial fibrillation.

PubMed

Matsuda, Hisao; Parwani, Abdul Shokor; Attanasio, Philipp; Huemer, Martin; Wutzler, Alexander; Blaschke, Florian; Haverkamp, Wilhelm; Boldt, Leif-Hendrik

2016-09-01

Catheter tissue contact force (CF) is an important factor for durable lesion formation during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Since CF varies in the beating heart, atrial rhythm during RFCA may influence CF. A high-density map and RFCA points were obtained in 25 patients undergoing RFCA of AF using a CF-sensing catheter (Tacticath, St. Jude Medical). The operators were blinded to the CF information. Contact type was classified into three categories: constant, variable, and intermittent contact. Average CF and contact type were analyzed according to atrial rhythm (SR vs. AF) and anatomical location. A total of 1364 points (891 points during SR and 473 points during AF) were analyzed. Average CFs showed no significant difference between SR (17.2 ± 11.3 g) and AF (17.2 ± 13.3 g; p = 0.99). The distribution of points with an average CF of ≥20 and <10 g also showed no significant difference. However, the distribution of excessive CF (CF ≥40 g) was significantly higher during AF (7.4 %) in comparison with SR (4.2 %; p < 0.05). At the anterior area of the right inferior pulmonary vein (RIPV), the average CF during AF was significantly higher than during SR (p < 0.05). Constant contact was significantly higher during AF (32.2 %) when compared to SR (9.9 %; p < 0.01). Although the average CF was not different between atrial rhythms, constant contact was more often achievable during AF than it was during SR. However, excessive CF also seems to occur more frequently during AF especially at the anterior part of RIPV.

Cardiac rhythm and pacemaking abnormalities in patients affected by endemic pemphigus in Colombia may be the result of deposition of autoantibodies, complement, fibrinogen, and other molecules.

PubMed

Abreu Velez, Ana Maria; Howard, Michael S; Velazquez-Velez, Jorge Enrique

2018-05-01

We previously showed that one-third of patients affected by endemic pemphigus foliaceus in El Bagre, Colombia (El Bagre-EPF), display autoreactivity to the heart. The purpose of this study was to investigate rhythm disturbances with the presence of autoantibodies and correlate them with ECG changes in these patients. We performed a study comparing 30 patients and 30 controls from the endemic area, matched by demographics, including age, sex, weight, work activities, and comorbidities. ECG as well as direct and indirect immunofluorescence, immunohistochemistry, and confocal microscopic studies focusing on cardiac node abnormalities were performed. Autopsies of 7 patients also were reviewed. The main ECG abnormalities seen in the El Bagre-EPF patients were sinus bradycardia (in one-half), followed by left bundle branch block, left posterior fascicular block, and left anterior fascicular block compared with the controls. One-third of the patients displayed polyclonal autoantibodies against the sinoatrial and/or AV nodes and the His bundle correlating with rhythm anomalies and delays in the cardiac conduction system (P <.01). The patient antibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), and myocardium-enriched zonula occludens-1-associated protein (MYZAP; Progen Biotechnik) (P <.01). One-third of the patients affected by El Bagre-EPF have rhythm abnormalities that slow the conduction of impulses in cardiac nodes and the cardiac conduction system. These abnormalities likely occur as a result of deposition of autoantibodies, complement, and other inflammatory molecules. We show for the first time that MYZAP is present in cardiac nodes. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Second-harmonic generation imaging of collagen fibers in myocardium for atrial fibrillation diagnosis

NASA Astrophysics Data System (ADS)

Tsai, Ming-Rung; Chiu, Yu-Wei; Lo, Men Tzung; Sun, Chi-Kuang

2010-03-01

Atrial fibrillation (AF) is the most common irregular heart rhythm and the mortality rate for patients with AF is approximately twice the mortality rate for patients with normal sinus rhythm (NSR). Some research has indicated that myocardial fibrosis plays an important role in predisposing patients to AF. Therefore, realizing the relationship between myocardial collagen fibrosis and AF is significant. Second-harmonic generation (SHG) is an optically nonlinear coherent process to image the collagen network. We perform SHG microscopic imaging of the collagen fibers in the human atrial myocardium. Utilizing the SHG images, we can identify the differences in morphology and the arrangement of collagen fibers between NSR and AF tissues. We also quantify the arrangement of the collagen fibers using Fourier transform images and calculating the values of angle entropy. We indicate that SHG imaging, a nondestructive and reproducible method to analyze the arrangement of collagen fibers, can provide explicit information about the relationship between myocardial fibrosis and AF.

QUest for the Arrhythmogenic Substrate of Atrial fibRillation in Patients Undergoing Cardiac Surgery (QUASAR Study): Rationale and Design.

PubMed

van der Does, Lisette J M E; Yaksh, Ameeta; Kik, Charles; Knops, Paul; Lanters, Eva A H; Teuwen, Christophe P; Oei, Frans B S; van de Woestijne, Pieter C; Bekkers, Jos A; Bogers, Ad J J C; Allessie, Maurits A; de Groot, Natasja M S

2016-06-01

The heterogeneous presentation and progression of atrial fibrillation (AF) implicate the existence of different pathophysiological processes. Individualized diagnosis and therapy of the arrhythmogenic substrate underlying AF may be required to improve treatment outcomes. Therefore, this single-center study aims to identify the arrhythmogenic areas underlying AF by intra-operative, high-resolution, multi-site epicardial mapping in 600 patients with different heart diseases. Participants are divided into 12 groups according to the underlying heart diseases and presence of prior AF episodes. Mapping is performed with a 192-electrode array for 5-10 s during sinus rhythm and (induced) AF of the entire atrial surface. Local activation times are converted into activation and wave maps from which various electrophysiological parameters are derived. Postoperative cardiac rhythm registrations and a 5-year follow-up will show the incidence of postoperative and persistent AF. This project provides the first step in the development of a tool for individual AF diagnosis and treatment.

Dynamical Landscape of Heart Rhythm in Long-Term Heart Transplant Recipients: A Way to Discern Erratic Rhythms

PubMed Central

Wdowczyk, Joanna; Makowiec, Danuta; Gruchała, Marcin; Wejer, Dorota; Struzik, Zbigniew R.

2018-01-01

It is commonly believed that higher values of heart rate variability (HRV) indices account for better organization of the network of feedback reflexes driving an organism's response to actual bodily needs. In order to evaluate this organization in heart transplant (HTX) recipients, 58 nocturnal Holter signals of 14 HTX patients were analyzed. Their dynamical properties were evaluated by short-term HRV indices and measures grounded on entropy. Estimates grouped according to the patients' clinical progress: free of complications versus with complications, and arranged in order of the length of time since the HTX, lead us to the conclusion that higher HRV is associated with a worse outcome for HTX patients. Moreover, short-term HRV indices that are constant, rather than increasing over time, serve well in the prognosis of the future state of a HTX patient. These findings suggest that increases observed in HRV indices are related to erratic rhythms resulting from remodeling of the cardiac tissue (including heterogeneous innervation) in long-term HTX patients. Therefore, we hypothesize that dynamical landscape markers (entropy and fragmentation measures together with the short-term HRV indices) can serve as a tool in the exploration of the genesis of (non-respiratory sinus) arrhythmia. PMID:29686620

[Atrial fibrillation].

PubMed

Spinar, J; Vítovec, J

2003-09-01

Atrial fibrilation is the most frequent arrhythmia, the occurrence increasing with age and associated diseases. The incidence at the age below 60 years is markedly lower than one per cent, whereas in persons above 80 years of age it exceeds six per cent. The occurrence in patients with heart failure is from 10% (NYHA II) up to 50% (NYHA IV). Atrial fibrillation is classified into that observed for the first time and permanent, respectively, while transient forms include paroxyzmal and persistent atrial fibrillation. The diagnosis is based on ECG recording, while echocardiography is most significant. The therapy includes two basic questions--anticoagulant or anti-aggregation treatment and the control of rhythm or frequency. The anticoagulant therapy should be introduced in all patients, where contraindications are not present, being necessary before every cardioversion, provided atrial fibrillation lasts more than two days. In patients without any heart disease and with a physiological echocardiogram it is possible to administer only anti-aggregation treatment. Cardioversion (the control of rhythm) is recommended to all symptomatic patients, in other cases and especially in older persons the control of frequency is safer and of more advantage. Electrical cardioversion is more effective that a pharmacological treatment, the sinus rhythm is preferably controlled by dofetilid, ibutilid, propafenon and amiodaron. For the control of heart rate beta-blockers, diltiazem, verapamil and digitalis are recommended.

Vitamin B12 affects non-photic entrainment of circadian locomotor activity rhythms in mice.

PubMed

Ebihara, S; Mano, N; Kurono, N; Komuro, G; Yoshimura, T

1996-07-15

Administration of vitamin B12 (VB12) has been reported to normalize human sleep-wake rhythm disorders such as non-24-h sleep-wake syndrome (HNS), delayed sleep phase syndrome (DSPS) or insomnia. However, the mechanisms of the action of VB12 on the rhythm disorders are unknown. In the present study, therefore, effects of VB12 on circadian rhythms of locomotor activity were examined in mice. In the first experiment, CBA/J mice were maintained under continuous light condition (LL) or blinded, and after free-running rhythms became stable, the mice were intraperitoneally injected with either VB12 or saline at a fixed time every day. In all the mice with tau > 24 h, saline injections resulted in entrainment of circadian rhythms, whereas not all the mice with tau < 24 h entrained to the injection. In contrast to saline injections, VB12 injections did not always induce entrainment and about half of the mice with tau > 24 h free-ran during the injection. In the second experiment, the amount of phase advances of circadian rhythms induced by a single injection of saline at circadian time (CT) 11 under LL was compared between the mice with and without VB12 silastic tubes. The results showed that the amplitude of phase advances was smaller in the mice with VB12 than those without VB12. In the third experiment, daily injections of saline were given to the mice with VB12 silastic tubes maintained under LL. In this chronic treatment of VB12 as well, attenuating effects of VB12 on saline-induced entrainment were observed. These results suggest that VB12 affects the mechanisms implicated in non-photic entrainment of circadian rhythms in mice.

[Atrial fibrillation and prolonged nocturnal cardiac arrests in a patient with obstructive sleep apnea syndrome. Successful correction of disorders by CPAP therapy].

PubMed

Bairambekov, E Sh; Pevzner, A V; Litvin, A Yu; Fomicheva, O A

The case history of a 46-year-old patient with obstructive sleep apnea syndrome was analyzed. The examination revealed fourth-degree obesity, prior myocardial infarction, persistent atrial fibrillation with nocturnal asystoles lasting as long as 14.3 sec. During selected drug therapy and regular application of secondary ventilation (continuous positive airway pressure (CPAP) therapy) used to correct breathing problems, there was a reduction in the signs of circulatory deficiency, cessation of cardiac pauses, and recovery of sinus rhythm. The therapeutic effect persisted during a 24-month follow-up.

Management of atrial fibrillation.

PubMed

Moukabary, Talal; Gonzalez, Mario D

2015-07-01

Atrial fibrillation is a very common clinical problem with a high prevalence that is expected to rise over time because of increasing risk factors (eg, age, obesity, hypertension). This high prevalence is also associated with high cost, because atrial fibrillation represents about 1% of overall health care spending. The management of atrial fibrillation involves multiple facets: (1) management of underlying disease if present and the management of atrial fibrillation risk factors, (2) prevention of thromboembolism, (3) control of the ventricular rate during atrial fibrillation, and (4) restoration and maintenance of normal sinus rhythm. Copyright © 2015 Elsevier Inc. All rights reserved.

Recurrent infarctions due to a dome-shaped pannus above the mitral valve prosthesis.

PubMed

Kasahara, Hirofumi; Inoue, Yoshito; Suzuki, Satoru

2016-01-01

This report describes a unique case of a 56-year-old female who suffered from recurrent stroke after double mechanical valve replacement. During the four years after the surgery, she remained in normal sinus rhythm, received adequate anticoagulation therapy, and no apparent left atrial thrombus was detected. She underwent redo surgery to prevent further stroke after fourth instance of cerebral infarction. Intraoperative findings revealed a 'dome-shaped' pannus formation covering the sewing ring of the mitral prosthesis circumferentially, probably leading to clot formation and repeated infarctions. She has been stroke free for three years after pannus resection.

Neurohormonal Blockade in Heart Failure

PubMed Central

Kotecha, Dipak; Atar, Dan; Hopper, Ingrid

2017-01-01

A key feature of chronic heart failure (HF) is the sustained activation of endogenous neurohormonal systems in response to impaired cardiac pumping and/or filling properties. The clinical use of neurohormonal blockers has revolutionised the care of HF patients over the past three decades. Drug therapy that is active against imbalance in both the autonomic and renin–angiotensin–aldosterone systems consistently reduces morbidity and mortality in chronic HF with reduced left ventricular ejection fraction and in sinus rhythm. This article provides an assessment of the major neurohormonal systems and their therapeutic blockade in patients with chronic HF. PMID:28785471

[Cox/maze III procedure combined with mitral valve replacement in treatment of rheumatic mitral valve disease with atrial fibrilation].

PubMed

Chen, Rukun; Wang, Yongqing; Chen, Yongbing; Chen, Suocheng

2002-06-25

To compare the curative effect of Cox/maze III procedure combined with mitral replacement and that of mitral valve replacement (MVR). Fifty-six patients suffering from rheumatic heart disease with atrial fibrillation (AF) were treated by Cox/maze III procedure combined with MVR (maze group). Another 56 age, sex, and heart function-matched patients with the same diagnosis underwent MVR alone during the same period. Warfarin was administered after operation in both groups. Comparison of operative complication and curative effects was made. The aortic cross-clamp time and cardio pulmonary bypass time (CPB) were longer in maze group than in MVT group (75 +/- 22 min vs 41 +/- 11 min, P < 0.05 and 124 +/- 40 min VS 68 +/- 19 min, P < 0.05). Bleeding happened after the heart reatored beating in 2 patients in maze group and in one patient in MVT group, all these 3 patients responding satisfactorily to hemostasis. The early post-operative mortality was 1.79% (1/56) in both groups. In maze group, AF disappeared in all patients but one who had node rhythm. Normal sinus rhythm was restored in 98.18% of the patients (54/55). Atrial contractility was restored in all patients with sinus rhythm. One year after operation, 98.18% patients' cardiac function changed to grade and 1.82% changed to grade II. In MVR group AF disappeared after operation temporarily for 24 hours in 7 patients and re-appeared, and AF disappeared in one patients for 2 years so far. One year after operation, the cardiac function of 94.6% patients in MVR group changed to grade I, of 3.6% patients to grade II, and of 1.8% patients to grade III. No serious hemorrhage relate d to anticoagulant therapy happened. One patient in MVR group suffered from hemiplegia due to cerebral embolism. The late mortality was 1.8% on maze group amd 3.6% in MVR group. Cox/maze III procedure combined with NVR is safe and effective in treating rheumatic heart disease with AF.

Coronary flow characteristics after a Bentall procedure with or without sinuses of Valsalva.

PubMed

de Paulis, Ruggero; Tomai, Fabrizio; Bertoldo, Fabio; Ghini, Anna S; Scaffa, Raffaele; Nardi, Paolo; Chiariello, Luigi

2004-07-01

The sinuses of Valsalva are known to contribute to the normal function of the aortic valve. Little is known about their role in promoting coronary artery blood flow. The aim of this study was to compare coronary artery flow characteristics among patients undergoing a Bentall operation by means of a conventional cylindrical Dacron conduit or with a new conduit with pseudosinuses of Valsalva or in patients retaining their natural sinuses of Valsalva after aortic valve and supracoronary ascending aorta replacement. One year after a Bentall procedure with a standard cylindrical Dacron conduit (7 patients, group A) or with the new conduit (7 patients, group B), or after aortic valve and ascending aortic replacement (control group, 7 patients, group C) coronary flow velocity reserve and diastolic to systolic time integral ratio at baseline and after maximal hyperemia (with 40 microg of adenosine) were assessed by using a 0.014-in. Doppler guidewire positioned in the middle portion of the left anterior descending coronary artery. All patients were in NYHA class I, sinus rhythm and free of coronary disease. Arterial blood pressures and heart rate were comparable among groups. Intracoronary Doppler measurements did not show any significant difference in coronary vascular reserve between the three groups (3.6+/-0.4 vs 3.1+/-0.7 vs 3.7+/-0.5, P = 0.2). A greater diastolic component at baseline was present in group B patients (5.5+/-1.9 vs 3.5+/-0.9 in group A and 3.7+/-0.9 in group C, P = 0.024). After maximal hyperemia the diastolic component increased slightly in group A patients (8%) while both in groups B and C significantly decreased (-15 and -20%, respectively) (P = 0.017). The presence of pseudosinuses of Valsalva does not influence coronary flow reserve. After maximal coronary vasodilation the increase in the systolic component of coronary flow is more evident in the presence of sinuses or pseudosinuses of Valsalva, thus suggesting that coronary flow pattern may be affected by the presence of sinuses.

Treatment of out-of-hospital supraventricular tachycardia: adenosine vs verapamil.

PubMed

Brady, W J; DeBehnke, D J; Wickman, L L; Lindbeck, G

1996-06-01

To compare the use of adenosine and the use of verapamil as out-of-hospital therapy for supraventricular tachycardia (SVT). A period of prospective adenosine use (March 1993 to February 1994) was compared with a historical control period of verapamil use (March 1990 to February 1991) for SVT. Data were obtained for SVT patients treated in a metropolitan, fire-department-based paramedic system serving a population of approximately 1 million persons. Standard drug protocols were used and patient outcomes (i.e., conversion rates, complications, and recurrences) were monitored. During the adenosine treatment period, 105 patients had SVT; 87 (83%) received adenosine, of whom 60 (69%) converted to a sinus rhythm (SR). Vagal maneuvers (VM) resulted in restoration of SR in 8 patients (7.6%). Some patients received adenosine for non-SVT rhythms: 7 sinus tachycardia, 18 atrial fibrilation, 7 wide-complex tachycardia (WCT), and 2 ventricular tachycardia; no non-SVT rhythm converted to SR and none of these patients experienced an adverse effect. Twenty-five patients were hemodynamically unstable (systolic blood pressure < 90 mm Hg), with 20 receiving drug and 13 converting to SR; 8 patients required electrical cardioversion. Four patients experienced adverse effects related to adenosine (chest pain dyspnea, prolonged bradycardia, and ventricular tachycardia). In the verapamil period, 106 patients had SVT: 52 (49%) received verapamil (p < 0.001, compared with the adenosine period), of whom 43 (88%) converted to SR (p = 0.11). Two patients received verapamil for WCT; neither converted to SR and both experienced cardiovascular collapse. VM resulted in restoration of SR in 12 patients (11.0%) (p = 0.52). Sixteen patients were hemodynamically unstable, with 5 receiving drug (p = 0.005) and 5 converting to SR; 9 patients required electrical cardioversion (p = 0.48). Four patients experienced adverse effects related to verapamil (hypotension ventricular tachycardia, ventricular fibrillation). Recurrence of SVT was noted in 2 adenosine patients and 2 verapamil patients in the out-of-hospital setting and in 23 adenosine patients and 15 verapamil patients after ED arrival, necessitating additional therapy (p = 0.48 and 0.88, for recurrence rates and types of additional therapies, respectively). Hospital diagnoses, outcomes, and ED dispositions were similar for the 2 groups. Adenosine and verapamil were equally successful in converting out-of-hospital SVT in patients with similar etiologies responsible for the SVT. Recurrence of SVT occurred at similar rates for the 2 medications. Rhythm misidentification remains a common issue in out-of-hospital cardiac care in this emergency medical services system.

Fundamental relations between short-term RR interval and arterial pressure oscillations in humans

NASA Technical Reports Server (NTRS)

Taylor, J. A.; Eckberg, D. L.

1996-01-01

BACKGROUND: One of the principal explanations for respiratory sinus arrhythmia is that it reflects arterial baroreflex buffering of respiration-induced arterial pressure fluctuations. If this explanation is correct, then elimination of RR interval fluctuations should increase respiratory arterial pressure fluctuations. METHODS AND RESULTS: We measured RR interval and arterial pressure fluctuations during normal sinus rhythm and fixed-rate atrial pacing at 17.2+/-1.8 (SEM) beats per minute greater than the sinus rate in 16 healthy men and 4 healthy women, 20 to 34 years of age. Measurements were made during controlled-frequency breathing (15 breaths per minute or 0.25 Hz) with subjects in the supine and 40 degree head-up tilt positions. We characterized RR interval and arterial pressure variabilities in low-frequency (0.05 to 0.15 Hz) and respiratory-frequency (0.20 to 0.30 Hz) ranges with fast Fourier transform power spectra and used cross-spectral analysis to determine the phase relation between the two signals. As expected, cardiac pacing eliminated beat-to-beat RR interval variability. Against expectations, however, cardiac pacing in the supine position significantly reduced arterial pressure oscillations in the respiratory frequency (systolic, 6.8+/-1.8 to 2.9 +/-0.6 mm Hg2/Hz, P=.017). In contrast, cardiac pacing in the 40 degree tilt position increased arterial pressure variability (systolic, 8.0+/-1.8 to 10.8 +/-2.6, P=.027). Cross-spectral analysis showed that 40 degree tilt shifted the phase relation between systolic pressure and RR interval at the respiratory frequency from positive to negative (9 +/-7 degrees versus -17+/-11 degrees, P=.04); that is, in the supine position, RR interval changes appeared to lead arterial pressure changes, and in the upright position, RR interval changes appeared to follow arterial pressure changes. CONCLUSIONS: These results demonstrate that respiratory sinus arrhythmia can actually contribute to respiratory arterial pressure fluctuations. Therefore, respiratory sinus arrhythmia does not represent simple baroreflex buffering of arterial pressure.

Effects of Contextual Sight-Singing and Aural Skills Training on Error-Detection Abilities.

ERIC Educational Resources Information Center

Sheldon, Deborah A.

1998-01-01

Examines the effects of contextual sight-singing and ear training on pitch and rhythm error detection abilities among undergraduate instrumental music education majors. Shows that additional training produced better error detection, particularly with rhythm errors and in one-part examples. Maintains that differences attributable to texture were…

[A case of coronary artery spasm during epidural anesthesia with continuous infusion of propofol].

PubMed

Inoue, Hisashi; Ogawa, Katsumi; Takano, Yoshito; Sato, Isao; Okuda, Yasuhisa

2003-07-01

A 50-year-old male patient was scheduled for left partial pulmonary resection and biopsy. The patient had neither complication nor history of ischemic heart disease. After arriving in the operation room, an epidural catheter was inserted into the epidural space at the T 4-5 intervertebral space. Anesthesia was induced with intravenous propofol 100 mg, fentanyl 100 microgram and vecuronium 6 mg and then a double lumen endotracheal tube was inserted. Anesthesia was maintained with O2 and air (FIO2 0.3-1.0), continuous infusion of propofol, intermittent intravenous administration of fentanyl and epidural injection of 1% lidocaine. Forty-five minutes after the start of operation, ECG showed an elevation of ST segment and soon it passed into ventricular tachycardia and ventricular fibrillation. The patient was treated with cardiopulmonary resuscitation. Fifteen minutes later, ECG returned to sinus rhythm but the elevation of ST segment remained. We considered that these cardiac events were due to coronary spasm, and started continuous infusion of nitroglycerin and nicorandil. One hour later, ST segment returned to normal. The possible inducing factors in this case were altered balance between sympathetic and parasympathetic nervous activity caused by infusion of propofol and epidural block, and alpha-stimulation caused by ephedrine.

Influence of White and Gray Matter Connections on Endogenous Human Cortical Oscillations

PubMed Central

Hawasli, Ammar H.; Kim, DoHyun; Ledbetter, Noah M.; Dahiya, Sonika; Barbour, Dennis L.; Leuthardt, Eric C.

2016-01-01

Brain oscillations reflect changes in electrical potentials summated across neuronal populations. Low- and high-frequency rhythms have different modulation patterns. Slower rhythms are spatially broad, while faster rhythms are more local. From this observation, we hypothesized that low- and high-frequency oscillations reflect white- and gray-matter communications, respectively, and synchronization between low-frequency phase with high-frequency amplitude represents a mechanism enabling distributed brain-networks to coordinate local processing. Testing this common understanding, we selectively disrupted white or gray matter connections to human cortex while recording surface field potentials. Counter to our original hypotheses, we found that cortex consists of independent oscillatory-units (IOUs) that maintain their own complex endogenous rhythm structure. IOUs are differentially modulated by white and gray matter connections. White-matter connections maintain topographical anatomic heterogeneity (i.e., separable processing in cortical space) and gray-matter connections segregate cortical synchronization patterns (i.e., separable temporal processing through phase-power coupling). Modulation of distinct oscillatory modules enables the functional diversity necessary for complex processing in the human brain. PMID:27445767

An Empirical Analysis of the Effects of a Possible Sinus Infection and Weighted Vest on Functional Analysis Outcomes of Self-Injury Exhibited by a Child with Autism

ERIC Educational Resources Information Center

Carter, Stacy L.

2005-01-01

Analogue functional analysis methodology was used to assess potential maintaining contingencies of episodic self-injurious behavior (SIB) of a 4-year-old child diagnosed with autism. Analogue conditions were presented within a multielement design when the child did, and did not exhibit signs of a possible sinus infection, and when the participant,…

Circadian melatonin concentration rhythm is lost in pregnant women with altered blood pressure rhythm.

PubMed

Tranquilli, A L; Turi, A; Giannubilo, S R; Garbati, E

2004-03-01

We assessed the correlation between the rhythm of melatonin concentration and circadian blood pressure patterns in normal and hypertensive pregnancy. Ambulatory 24-h blood pressure and blood samples every 4 h were monitored in 16 primigravidae who had shown an abnormal circadian blood pressure pattern (eight pre-eclamptic and eight normotensive) in pregnancy and 6-12 months after pregnancy. The circadian rhythm was analyzed by chronobiological measures. Eight normotensive women with maintained blood pressure rhythm served as controls. During pregnancy, melatonin concentration was significantly higher in pre-eclamptic than in normotensive women (pre-eclampsia, 29.4 +/- 1.9 pg/ml, normotensin, altered rhythm, 15.6 +/- 2.1; controls, 22.7 +/- 1.8; p < 0.001). This difference faded after pregnancy, owing to the fall observed in pre-eclampsia (11.8 +/- 3.2 pg/ml, 9.8 +/- 2.1, and 11.1 +/- 2.0, respectively; NS). The rhythm of melatonin concentration was lost in all pregnant women with loss of blood pressure rhythm. After pregnancy, normotensive women showed a reappearance of both melatonin and blood pressure rhythm, whereas pre-eclamptic women showed a reappearance of blood pressure but not melatonin rhythm. The loss of blood pressure rhythm in pregnancy is consistent with the loss of melatonin concentration rhythm. In pre-eclamptic women, the normalization of blood pressure rhythm, while melatonin rhythm remained altered, suggests a temporal or causal priority of circadian concentration of melatonin in the determination of blood pressure trend.

Atrial fibrillation patients with isolated pulmonary veins: Is sinus rhythm achievable?

PubMed

Szilágyi, Judit; Marcus, Gregory M; Badhwar, Nitish; Lee, Byron K; Lee, Randall J; Vedantham, Vasanth; Tseng, Zian H; Walters, Tomos; Scheinman, Melvin; Olgin, Jeffrey; Gerstenfeld, Edward P

2017-07-01

The cornerstone of atrial fibrillation (AF) ablation is isolation of the pulmonary veins (PVs). Patients with recurrent AF undergoing repeat ablation usually have PV reconnection (PVr). The ablation strategy and outcome of patients undergoing repeat ablation who have persistent isolation of all PVs (PVi) at the time of repeat ablation is unknown. We studied consecutive patients with recurrent AF undergoing repeat ablation and compared patients with PVi to those with PVr. One hundred fifty-two patients underwent repeat ablation, and of these, 25 patients (16.4%) had PVi. Patients with PVi underwent ablation targeting any isoproterenol induced AF triggers, atrial substrate, or inducible atrial tachycardias or flutters. Patients with PVi compared to PVr were more likely to have a history of persistent AF (64% vs. 26%; P < 0.0001), obesity (BMI 30.4 vs. 28.2; P = 0.05), and prior use of contact force sensing catheters (28% vs. 0.8%, P < 0.0001). After a mean follow-up of 19 ± 15 months, 56% of PVi patients remained in sinus rhythm compared to 76.3% of PVr patients (P = 0.036). In a multivariable model, PVi patients and those with cardiomyopathy had a higher risk of recurrent atrial tachyarrhythmias (HR = 3.6 95%, CI 1.6-8.3, P = 0.002 and HR = 6.2, 95% CI 2.3-16.3, P < 0.0001, respectively). In patients who have all PVs isolated at the time of the redo AF ablation, a strategy of targeting non-PV AF triggers and inducible flutters can still lead to AF freedom in more than half of patients. Patients with PVr, however, have a better long-term outcome. © 2017 Wiley Periodicals, Inc.

Maternal steroid therapy for fetuses with second-degree immune-mediated congenital atrioventricular block: a systematic review and meta-analysis.

PubMed

Ciardulli, Andrea; D'Antonio, Francesco; Magro-Malosso, Elena R; Manzoli, Lamberto; Anisman, Paul; Saccone, Gabriele; Berghella, Vincenzo

2018-03-07

To explore the effect of maternal fluorinated steroid therapy on fetuses affected by second-degree immune-mediated congenital atrioventricular block. Studies reporting the outcome of fetuses with second-degree immune-mediated congenital atrioventricular block diagnosed on prenatal ultrasound and treated with fluorinated steroids compared with those not treated were included. The primary outcome was the overall progression of congenital atrioventricular block to either continuous or intermittent third-degree congenital atrioventricular block at birth. Meta-analyses of proportions using random effect model and meta-analyses using individual data random-effect logistic regression were used. Five studies (71 fetuses) were included. The progression rate to congenital atrioventricular block at birth in fetuses treated with steroids was 52% (95% confidence interval 23-79) and in fetuses not receiving steroid therapy 73% (95% confidence interval 39-94). The overall rate of regression to either first-degree, intermittent first-/second-degree or sinus rhythm in fetuses treated with steroids was 25% (95% confidence interval 12-41) compared with 23% (95% confidence interval 8-44) in those not treated. Stable (constant) second-degree congenital atrioventricular block at birth was present in 11% (95% confidence interval 2-27) of cases in the treated group and in none of the newborns in the untreated group, whereas complete regression to sinus rhythm occurred in 21% (95% confidence interval 6-42) of fetuses receiving steroids vs. 9% (95% confidence interval 0-41) of those untreated. There is still limited evidence as to the benefit of administered fluorinated steroids in terms of affecting outcome of fetuses with second-degree immune-mediated congenital atrioventricular block. © 2018 Nordic Federation of Societies of Obstetrics and Gynecology.

Assessment of atrial electromechanical interval using echocardiography after catheter ablation in patients with persistent atrial fibrillation.

PubMed

Chen, Xiaodong; Chen, Minglong; Wang, Yingying; Yang, Bing; Ju, Weizhu; Zhang, Fengxiang; Cao, Kejiang

2016-11-01

We sought to investigate variation of atrial electromechanical interval after catheter ablation procedure in patients with persistent atrial fibrillation using pulse Doppler (PW) and pulse tissue Doppler imaging (PW-TDI). A total of 25 consecutive in-patients with persistent atrial fibrillation, who restored sinus rhythm after ablation procedure, were recruited in our cardiac center. Echocardiography was performed on each patient at 2 hours, 1 day, 5 days, 1 month and 3 months after the ablation therapy, and atrial electromechanical delay was measured simultaneously by PW and PW-TDI. There was no significant difference between PW and TDI in measuring atrial electromechanical delay. However, at postoperative 2 hours, peak A detection rates were mathematically but nonsignificantly greater by PW-TDI than by PW. Second, there was a significant decreasing trend in atrial electromechanical interval from postoperative 2 hours to 3 months, but only postoperative 2-hour atrial electromechanical interval was significantly greater than atrial electromechanical interval at other time. Lastly, patients without postoperative 2-hour atrial electromechanical interval had a significantly longer duration of atrial fibrillation as compared to those with postoperative 2-hour atrial electromechanical interval, by the PW or by PW-TDI, respectively. In patients with persistent atrial fibrillation, atrial electromechanical interval may decrease significantly within the first 24 hours after ablation but remain consistent later, and was significantly related to patients' duration of atrial fibrillation. Atrial electromechanical interval, as a potential predicted factor, is recommended to be measured by either PW or TDI after 24 hours, when patients had recovered sinus rhythm by radiofrequency ablation. © 2016 by the Journal of Biomedical Research. All rights reserved.

Comparing energy sources for surgical ablation of atrial fibrillation: a Bayesian network meta-analysis of randomized, controlled trials.

PubMed

Phan, Kevin; Xie, Ashleigh; Kumar, Narendra; Wong, Sophia; Medi, Caroline; La Meir, Mark; Yan, Tristan D

2015-08-01

Simplified maze procedures involving radiofrequency, cryoenergy and microwave energy sources have been increasingly utilized for surgical treatment of atrial fibrillation as an alternative to the traditional cut-and-sew approach. In the absence of direct comparisons, a Bayesian network meta-analysis is another alternative to assess the relative effect of different treatments, using indirect evidence. A Bayesian meta-analysis of indirect evidence was performed using 16 published randomized trials identified from 6 databases. Rank probability analysis was used to rank each intervention in terms of their probability of having the best outcome. Sinus rhythm prevalence beyond the 12-month follow-up was similar between the cut-and-sew, microwave and radiofrequency approaches, which were all ranked better than cryoablation (respectively, 39, 36, and 25 vs 1%). The cut-and-sew maze was ranked worst in terms of mortality outcomes compared with microwave, radiofrequency and cryoenergy (2 vs 19, 34, and 24%, respectively). The cut-and-sew maze procedure was associated with significantly lower stroke rates compared with microwave ablation [odds ratio <0.01; 95% confidence interval 0.00, 0.82], and ranked the best in terms of pacemaker requirements compared with microwave, radiofrequency and cryoenergy (81 vs 14, and 1, <0.01% respectively). Bayesian rank probability analysis shows that the cut-and-sew approach is associated with the best outcomes in terms of sinus rhythm prevalence and stroke outcomes, and remains the gold standard approach for AF treatment. Given the limitations of indirect comparison analysis, these results should be viewed with caution and not over-interpreted. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Altered transient outward current in human atrial myocytes of patients with reduced left ventricular function.

PubMed

Schreieck, J; Wang, Y; Overbeck, M; Schömig, A; Schmitt, C

2000-02-01

Electrophysiologic remodeling is involved in the self-perpetuation of atrial fibrillation. To define whether differences in atrial electrophysiology already are present in patients with increased susceptibility for atrial fibrillation, we compared patients in sinus rhythm with and without heart failure. Atrial specimens were obtained from patients with reduced left ventricular ejection fraction (LVEF; n = 10) and normal LVEF (n = 16) who were undergoing aortocoronary bypass surgery and from donor hearts (n = 4). Enzymatically isolated atrial myocytes were investigated by whole cell, patch clamp techniques. Total outward current was significantly larger in myocytes of hearts with low LVEF than normal LVEF (19.4 +/- 1.3 vs 15.1 +/- 1.2 pA/pF at pulses to +60 mV, respectively). Analysis of inactivation time courses of different outward current components revealed that the observed current difference is due to the transient calcium-independent outward current I(to1) which is twice as large in the low LVEF group than in the normal LVEF group (9.4 +/- 0.9 vs 4.7 +/- 0.4 pA/pF at pulses to +60 mV, respectively). I(to1) recovery from inactivation was significantly more rapid in myocytes of hearts with low LVEF, and action potential plateau in these cells was significantly shorter. The results of I(to1) and action potential measurements in atrial myocytes of donor hearts were very similar to the results of patients with preserved heart function. I(to1) in human atrial myocytes of patients with reduced LVEF has an increased density and altered kinetics in sinus rhythm. These differences in outward current may explain the reduced plateau phase of action potentials.

Spatial distribution of conduction disorders during sinus rhythm.

PubMed

Lanters, Eva A H; Yaksh, Ameeta; Teuwen, Christophe P; van der Does, Lisette J M E; Kik, Charles; Knops, Paul; van Marion, Denise M S; Brundel, Bianca J J M; Bogers, Ad J J C; Allessie, Maurits A; de Groot, Natasja M S

2017-12-15

Length of lines of conduction block (CB) during sinus rhythm (SR) at Bachmann's bundle (BB) is associated with atrial fibrillation (AF). However, it is unknown whether extensiveness of CB at BB represents CB elsewhere in the atria. We aim to investigate during SR 1) the spatial distribution and extensiveness of CB 2) whether there is a predilection site for CB and 3) the association between CB and incidence of post-operative AF. During SR, epicardial mapping of the right atrium (RA), BB and left atrium was performed in 209 patients with coronary artery disease. The amount of conduction delay (CD, Δlocal activation time ≥7ms) and CB (Δ≥12ms) was quantified as % of the mapping area. Atrial regions were compared to identify potential predilection sites for CD/CB. Correlations between CD/CB and clinical characteristics were tested. Areas with CD or CB were present in all patients, overall prevalence was respectively 1.4(0.2-4.0) % and 1.3(0.1-4.3) %. Extensiveness and spatial distribution of CD/CB varied considerably, however occurred mainly at the superior intercaval RA. Of all clinicalcharacteristics, CD/CB only correlated weakly with age and diabetes (P<0.05). A 1% increase in CD or CB caused a 1.1-1.5ms prolongation of the activation time (P<0.001). There was no correlation between CD/CB and post-operative AF. CD/CB during SR in CABG patients with electrically non-remodeled atria show considerable intra-atrial, but also inter-individual variation. Despite these differences, a predilection site is present at the superior intercaval RA. Extensiveness of CB at the superior intercaval RA or BB does not reflect CB elsewhere in the atria and is not associated with post-operative AF. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantification of the Arrhythmogenic Effects of Spontaneous Atrial Extrasystole Using High-Resolution Epicardial Mapping.

PubMed

Teuwen, Christophe P; Kik, Charles; van der Does, Lisette J M E; Lanters, Eva A H; Knops, Paul; Mouws, Elisabeth M J P; Bogers, Ad J J C; de Groot, Natasja M S

2018-01-01

Atrial extrasystoles (AES) can initiate atrial fibrillation. However, the impact of spontaneous AES on intra-atrial conduction is unknown. The aims of this study were to examine conduction disorders provoked by AES and to correlate these conduction differences with patient characteristics, mapping locations, and type of AES. High-resolution epicardial mapping (electrodes N=128 or N=192; interelectrode distance, 2 mm) of the entire atrial surface was performed in patients (N=164; 69.5% male; age 67.2±10.5 years) undergoing open-chest cardiac surgery. AES were classified as premature, aberrant, or prematurely aberrant. Conduction delay and conduction block were quantified during sinus rhythm and AES and subsequently compared. Median incidence of conduction delay and conduction block during sinus rhythm was 1.2% (interquartile, 0%-2.3%) and 0.4% (interquartile, 0%-2.1%). In comparison, the median incidence of conduction delay and conduction block during 339 AES was respectively 2.8% (interquartile, 1.3%-4.6%) and 2.2% (interquartile, 0.3%-5.1%) and differed between the types of AES (prematurely aberrant>aberrant>premature). The degree of prematurity was not associated with a higher incidence of conduction disorders ( P >0.05). In contrast, a higher degree of aberrancy was associated with a higher incidence of conduction disorders; AES emerging as epicardial breakthrough provoked most conduction disorders ( P ≥0.002). AES caused most conduction disorders in patients with diabetes mellitus and left atrial dilatation ( P <0.05). Intraoperative high-resolution epicardial mapping showed that conduction disorders are mainly provoked by prematurely aberrant AES, particularly in patients with left atrial dilation and diabetes mellitus or emerging as epicardial breakthrough. © 2017 American Heart Association, Inc.

A randomized pilot study of optimization of cardiac resynchronization therapy in sinus rhythm patients using a peak endocardial acceleration sensor vs. standard methods.

PubMed

Ritter, Philippe; Delnoy, Peter Paul H M; Padeletti, Luigi; Lunati, Maurizio; Naegele, Herbert; Borri-Brunetto, Alberto; Silvestre, Jorge

2012-09-01

Non-response rate to cardiac resynchronization therapy (CRT) might be decreased by optimizing device programming. The Clinical Evaluation on Advanced Resynchronization (CLEAR) study aimed to assess the effects of CRT with automatically optimized atrioventricular (AV) and interventricular (VV) delays, based on a Peak Endocardial Acceleration (PEA) signal system. This multicentre, single-blind study randomized patients in a 1 : 1 ratio to CRT optimized either automatically by the PEA-based system, or according to centres' usual practices, mostly by echocardiography. Patients had heart failure (HF) New York Heart Association (NYHA) functional class III/IV, left ventricular ejection fraction (LVEF) <35%, QRS duration >150 or >120 ms with mechanical dyssynchrony. Follow-up was 1 year. The primary endpoint was the proportion of patients who improved their condition at 1 year, based on a composite of all-cause death, HF hospitalizations, NYHA class, and quality of life. In all, 268 patients in sinus rhythm (63% men; mean age: 73.1 ± 9.9 years; mean NYHA: 3.0 ± 0.3; mean LVEF: 27.1 ± 8.1%; and mean QRS duration: 160.1 ± 22.0 ms) were included and 238 patients were randomized, 123 to PEA and 115 to the control group. At 1 year, 76% of patients assigned to PEA were classified as improved, vs. 62% in the control group (P= 0.0285). The percentage of patients with improved NYHA class was significantly (P= 0.0020) higher in the PEA group than in controls. Fatal and non-fatal adverse events were evenly distributed between the groups. PEA-based optimization of CRT in HF patients significantly increased the proportion of patients who improved with therapy, mainly through improved NYHA class, after 1 year of follow-up.

Cardioversion Efficacy Using Pulsed Biphasic or Biphasic Truncated Exponential Waveforms: A Randomized Clinical Trial.

PubMed

Schmidt, Anders S; Lauridsen, Kasper G; Adelborg, Kasper; Torp, Peter; Bach, Leif F; Jepsen, Simon M; Hornung, Nete; Deakin, Charles D; Rickers, Hans; Løfgren, Bo

2017-03-08

Several different defibrillators are currently used for cardioversion and defibrillation of cardiac arrhythmias. The efficacy of a novel pulsed biphasic (PB) waveform has not been compared to other biphasic waveforms. Accordingly, this study aims to compare the efficacy and safety of PB shocks with biphasic truncated exponential (BTE) shocks in patients undergoing cardioversion of atrial fibrillation or -flutter. This prospective, randomized study included patients admitted for elective direct current cardioversion. Patients were randomized to receive cardioversion using either PB or BTE shocks. We used escalating shocks until sinus rhythm was obtained or to a maximum of 4 shocks. Patients randomized to PB shocks received 90, 120, 150, and 200 J and patients randomized to BTE shocks received 100, 150, 200, and 250 J, as recommended by the manufacturers. In total, 69 patients (51%) received PB shocks and 65 patients (49%) BTE shocks. Successful cardioversion, defined as sinus rhythm 4 hours after cardioversion, was achieved in 43 patients (62%) using PB shocks and in 56 patients (86%) using BTE shocks; ratio 1.4 (95% CI 1.1-1.7) ( P =0.002). There was no difference in safety (ie, myocardial injury judged by changes in high-sensitive troponin I levels; ratio 1.1) (95% CI 1.0-1.3), P =0.15. The study was terminated prematurely because of an adverse event. Cardioversion using a BTE waveform was more effective when compared with a PB waveform. There was no difference in safety between the 2 waveforms, as judged by changes in troponin I levels. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02317029. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Catheter-induced linear lesions in the left atrium in patients with atrial fibrillation: an electroanatomic study.

PubMed

Ernst, Sabine; Ouyang, Feifan; Löber, Felix; Antz, Matthias; Kuck, Karl-Heinz

2003-10-01

In this study using radiofrequency current and the electroanatomic mapping system CARTO, four line designs were tested in 84 patients suffering from drug-refractory atrial fibrillation (AFib). Prevention of AFib by trigger elimination within the pulmonary veins (PVs) has been recently reported, but the success may be lesser in patients with chronic AFib or large atria requiring linear lesion deployment. Type A encircled the ostia of all four PVs with a connection to the mitral annulus (MA). In type B, three lines connected anatomic barriers. Type C encircled both septal and lateral PVs with connections between PVs and to the MA. Type D encircled PVs only. In the initial 12 patients (type D/1), line validation was performed without, and in 23 patients (type D/2) with, an additional catheter inside the encircled PVs. The ability to achieve completeness of all intended lines was 5% in type A, 21% in type B, 29% in C, 66% in type D/1, and 61% in type D/2. This resulted in stable sinus rhythm in 19% (4/21 patients) in type A, 32% (6/19 patients) in type B, 50% (7/14 patients) in type C, 58% (7/12 patients) in type D/1, and 65% (15/23 patients) in type D/2, respectively, over a mean follow-up of 620 +/- 376 days. Besides thromboembolic events (one stroke and one transient ischemic attack), total occlusion of a PV was a major complication in one patient, and acute tamponade in two patients. Complete lesions in the left atrium were difficult to achieve using conventional radiofrequency current technology, but were associated with sinus rhythm in 74% of patients during long-term follow-up, whereas incomplete lesions led mostly to recurrences of AFib or gap-related atrial tachycardia.

Association between left atrial phasic conduit function and early atrial fibrillation recurrence in patients undergoing electrical cardioversion.

PubMed

Degiovanni, Anna; Boggio, Enrico; Prenna, Eleonora; Sartori, Chiara; De Vecchi, Federica; Marino, Paolo N

2018-04-01

Diastolic dysfunction promotes atrial fibrillation (AF) inducing left atrial (LA) remodeling, with chamber dilation and fibrosis. Predominance of LA phasic conduit (LAC) function should reflect not only chamber alterations but also underlying left ventricular (LV) filling impairment. Thus, LAC was tested as possible predictor of early AF relapse after electrical cardioversion (EC). 96 consecutive patients, who underwent EC for persistent non-valvular AF, were prospectively enrolled. Immediately after successful EC (3 h ± 15 min), an echocardiographic apical four-chamber view was acquired with transmitral velocities, annular tissue Doppler and simultaneous LV and LA three-dimensional full-volume datasets. Then, from LA-LV volumetric curves we computed LAC as: [(LV maximum - LV minimum) - (LA maximum - LA minimum) volume], expressed as % LV stroke volume. LA pump, immediately post-EC, was assumed and verified as being negligible. Sinus rhythm persistence at 1 month was checked with ECG-Holter monitoring. At 1 month 62 patients were in sinus rhythm and 34 in AF. AF patients presented pre-EC higher E/é values (p = 0.012), no major LA volume differences (p = NS), but a stiffer LV cavity (p = 0.012) for a comparable LV capacitance (p = 0.461). Conduit contributed more (p < 0.001) to LV stroke volume in AF subpopulation. Multiple regression revealed LAC as the most significant AF predictor (p = 0.013), even after correction for biometric characteristics and pharmacotherapy (p = 0.008). Our data suggest that LAC larger contribution to LV filling soon after EC reflects LA-LV stiffening, which skews atrioventricular interaction leading to AF perpetuation and makes conduit dominance a powerful predictor of early AF recurrence.

An individual patient meta-analysis of five randomized trials assessing the effects of cardiac resynchronization therapy on morbidity and mortality in patients with symptomatic heart failure.

PubMed

Cleland, John G; Abraham, William T; Linde, Cecilia; Gold, Michael R; Young, James B; Claude Daubert, J; Sherfesee, Lou; Wells, George A; Tang, Anthony S L

2013-12-01

Cardiac resynchronization therapy (CRT) with or without a defibrillator reduces morbidity and mortality in selected patients with heart failure (HF) but response can be variable. We sought to identify pre-implantation variables that predict the response to CRT in a meta-analysis using individual patient-data. An individual patient meta-analysis of five randomized trials, funded by Medtronic, comparing CRT either with no active device or with a defibrillator was conducted, including the following baseline variables: age, sex, New York Heart Association class, aetiology, QRS morphology, QRS duration, left ventricular ejection fraction (LVEF), and systolic blood pressure. Outcomes were all-cause mortality and first hospitalization for HF or death. Of 3782 patients in sinus rhythm, median (inter-quartile range) age was 66 (58-73) years, QRS duration was 160 (146-176) ms, LVEF was 24 (20-28)%, and 78% had left bundle branch block. A multivariable model suggested that only QRS duration predicted the magnitude of the effect of CRT on outcomes. Further analysis produced estimated hazard ratios for the effect of CRT on all-cause mortality and on the composite of first hospitalization for HF or death that suggested increasing benefit with increasing QRS duration, the 95% confidence bounds excluding 1.0 at ∼140 ms for each endpoint, suggesting a high probability of substantial benefit from CRT when QRS duration exceeds this value. QRS duration is a powerful predictor of the effects of CRT on morbidity and mortality in patients with symptomatic HF and left ventricular systolic dysfunction who are in sinus rhythm. QRS morphology did not provide additional information about clinical response. NCT00170300, NCT00271154, NCT00251251.

Percutaneous ligation of the left atrial appendage results in atrial electrical substrate modification.

PubMed

Syed, Faisal F; Rangu, Venu; Bruce, Charles J; Johnson, Susan B; Danielsen, Andrew; Gilles, Emily J; Ladewig, Dorothy J; Mikell, Susan B; Berhow, Steven; Wahnschaffe, Douglas; Suddendorf, Scott H; Asirvatham, Samuel J; Friedman, Paul A

2015-03-01

Debulking of electrically active atrial tissue may reduce the mass of fibrillating tissue during atrial fibrillation, eliminate triggers, and promote maintenance of normal sinus rhythm (NSR). We investigated whether left atrial appendage (LAA) ligation results in modification of atrial electrical substrate. Healthy male mongrel dogs (N = 20) underwent percutaneous epicardial LAA ligation. The ligation system grabber recorded LAA local electrograms (EGM) continuously before, during, and after closure. Successful ligation with a preloaded looped suture was confirmed intraprocedurally by LAA Doppler flow cessation on transesophageal echocardiography (TEE) and loss of LAA electrical activity, and after procedure by direct necropsic visualization. P-wave duration on surface electrocardiograms was measured immediately before and after LAA closure. Percent P-wave duration reduction was correlated with preclosure LAA internal dimensions measured by TEE and external dimensions measured on necropsy specimens to investigate associations of LAA geometry with the extent of electrical substrate modification. LAA ligation was successful in all dogs and accompanied by loss of LAA EGM. P-wave duration reduced immediately on ligation (mean 75 ms preligation to 63 ms postligation; mean difference ± standard error, 12 ± 1 ms; P < 0.0001). Percent P-wave reduction was associated with larger LAA longitudinal cross-sectional area (R(2) = 0.263, P = 0.04) and smaller external circumference (R(2) = 0.687, P = 0.04). All dogs were in sinus rhythm. Percutaneous LAA ligation results in its acute electrical isolation and atrial electrical substrate modification, the degree of which is associated with LAA geometry. These electrical changes raise the possibility that LAA ligation may promote NSR by removing LAA substrate and triggers. Copyright © 2015 Elsevier Inc. All rights reserved.

Intermediate outcomes of rheumatic mitral stenosis post-balloon mitral valvotomy.

PubMed

Sharma, Jugal; Goel, Pravin K; Pandey, Chandra Mani; Awasthi, Ashish; Kapoor, Aditya; Tewari, Satyendra; Garg, Naveen; Kumar, Sudeep; Khanna, Roopali

2015-10-01

Balloon mitral valvotomy is a standard therapeutic modality for managing rheumatic mitral stenosis. Data on intermediate outcomes of this procedure are limited. Thus we investigated the intermediate outcome after balloon mitral valvotomy performed at a large tertiary center in India. Case records and follow-up data of 2330 patients who underwent valvotomy from June 1999 to December 2005 were retrieved from the hospital information system and analyzed. The median age of the patients was 32 ± 11 years, 1363 were female including 36 who were pregnant, and 379 were in atrial fibrillation. Follow-up ranged from 1 to 14 years (mean 4.5 years, median 4.0 years). The procedural success rate was 93%. Atrial fibrillation, higher functional class, and worse valve morphology were independent predictors of a poor procedural outcome. Patients with sinus rhythm had better event-free survival (10.43 years, 95% confidence interval: 10.1-10.7) compared to those with atrial fibrillation (8.17 years, 95% confidence interval: 7.5-8.8). Patients who achieved a valve area >1.75 cm(2) had a better event-free survival (11.7 years, 95% confidence interval: 11.4-12.0) than those with a valve area of 1.5-1.74 cm(2) (9.3 years, 95% confidence interval: 9.0-9.7). On multivariate analysis, higher functional class, worse valve morphology, and new significant mitral regurgitation were predictors of a poor outcome. Achieved mitral valve area >1.75 cm(2) was an independent predictor of a good outcome. Patients with sinus rhythm, less gross valve deformity, and a post-balloon mitral valvotomy area >1.75 cm(2) had better intermediate outcomes. © The Author(s) 2015.

Results of preventive radioiodine therapy in euthyroid patients with history of hyperthyroidism prior to administration of amiodarone with permanent atrial fibrillation--a preliminary study.

PubMed

Czarnywojtek, Agata; Zgorzalewicz-Stachowiak, Małgorzata; Woliński, Kosma; Płazińska, Maria Teresa; Miechowicz, Izabela; Kwiecińska, Barbara; Czepczyński, Rafał; Królicki, Leszek; Ruchała, Marek

2014-01-01

Radioiodine (RAI) therapy is a standard procedure in the treatment of hyperthyroidism. However, the use of RAI in euthyroid patients requiring chronic administration of amiodarone (AM) where other antiarrhythmic drugs may lack efficacy is still controversial. The aim of this study was to assess the safety and efficacy of an AM therapy prior to treatment with radioiodine therapy in euthyroid patients with permanent atrial fibrillation (PAF), who had been treated for hyperthyroidism in the past. This was a retrospective observational study. Patients were assessed at baseline and two, six, eight, and 12 months after RAI therapy. 17 euthyroid patients with PAF were qualified to the RAI (female/male 3/14; age range 65 to 87, median 71). The patients required chronic administration of AM as a prophylaxis against sudden death. Each patient received an ablative dose of 800 MBq (22 mCi) of 131I. At baseline and during follow-up, no side effects of the therapy and no signs of drug intolerance were observed. Subclinical hyperthyroidism occurred in two (11.8%) cases after two months of RAI and five weeks of AM administration. In this situation, RAI therapy was repeated. Three patients (17.6%) after six months, and another two (11.8%) after eight months, required an additional dose of 131I due to amiodarone-induced thyrotoxicosis (AIT). Twelve patients (70.6%) returned to spontaneous sinus rhythm within two months. Fourteen patients (82.4%) had sinus rhythm during follow-up after six and 12 months of treatment. Preventive RAI in euthyroid (but previously hyperthyroid) patients with PAF before administration of AM may be the method of choice. This is particularly important for patients who will require permanent AM administration as a life-saving drug.

Electrocardiographic findings in Emergency Department patients with pulmonary embolism.

PubMed

Richman, Peter B; Loutfi, Hassan; Lester, Steven J; Cambell, Patricia; Matthews, Jessica; Friese, Jeremy; Wood, Joseph; Kasper, David; Chen, Frederick; Mandell, Mark

2004-08-01

To assess the pre-study, null hypothesis that there is no difference in the electrocardiogram (EKG) findings for Emergency Department (ED) patients who rule in vs. rule out for suspected pulmonary embolism, a retrospective review of a cohort of patients with pulmonary embolism and their controls was conducted in an academic, suburban ED. Patients who were evaluated in the ED during a one-year study period for symptoms suggestive of pulmonary embolism were eligible for inclusion. All patients with pulmonary embolism and sex- and age-matched controls comprised the final study groups. Two board-certified cardiologists reviewed each patient's EKG. There were 350 eligible patients identified; 49 patients with pulmonary embolism and 49 controls were entered into the study. The most common rhythm observed in both groups was normal sinus rhythm (67.3% cases vs. 68.6 % controls; p = 1.0). Abnormalities believed to be associated with pulmonary embolism occurred with similar frequency in both case and control groups (sinus tachycardia [18.8 % vs. 11.8%, respectively; p = 0.40]), incomplete right bundle branch block (4.2% vs. 0.0%, respectively; p = 0.24), complete right bundle branch block (4.2% vs. 6.0, respectively; p = 1.0), S1Q3T3 pattern (2.1 vs. 0.0, respectively; p = 0.49), S1Q3 pattern (0.0 vs. 0.0), and extreme right axis (0.0 vs. 0.0). New EKG changes were identified more frequently for patients with pulmonary embolism (33.3% vs. 12.5% controls; p = 0.03), but specific findings were rarely different between cases and controls. In our cohort of ED patients, we did not identify EKG features that are likely to help distinguish patients with pulmonary embolism from those who rule out for the disease.

Role of Left Ventricular Diastolic Dysfunction in Predicting Atrial Fibrillation Recurrence after Successful Electrical Cardioversion

PubMed Central

Melduni, Rowlens M.; Cullen, Michael W.

2013-01-01

The role of left ventricular (LV) diastolic dysfunction in predicting atrial fibrillation (AF) recurrence after successful electrical cardioversion is largely unknown. Studies suggest that there may be a link between abnormal LV compliance and the initial development, and recurrence of AF after electrical cardioversion. Although direct-current cardioversion (DCCV) is a well-established and highly effective method to convert AF to sinus rhythm, it offers little else beyond immediate rate control because it does not address the underlying cause of AF. Preservation of sinus rhythm after successful cardioversion still remains a challenge for clinicians. Despite the use of antiarrhythmic drugs and serial cardioversions, the rate of AF recurrence remains high in the first year. Current evidence suggests that diastolic dysfunction, which is associated with atrial volume and pressure overload, may be a mechanism underlying the perpetuating cycle of AF recurrence following successful electrical cardioversion. Diastolic dysfunction is considered to be a defect in the ability of the myofibrils, which have shortened against a load in systole to eject blood into the high-pressure aorta, to rapidly or completely return to their resting length. Consequently, LV filling is impaired and the non-compliant left ventricle is unable to fill at low pressures. As a result, left atrial and pulmonary vein pressure rises, and electrical and structural remodeling of the atrial myocardium ensues, creating a vulnerable substrate for AF. In this article, we review the current evidence highlighting the association of LV diastolic dysfunction with AF recurrence after successful electrical cardioversion and provide an approach to the management of LV diastolic dysfunction to prevent AF recurrence. PMID:23525127

[Atrial fibrillation before and after pacemaker implantation (WI and DDD) in patients with complete atrioventricular block].

PubMed

Matusik, Paweł; Woznica, Natalia; Lelakowsk, Jacek

2010-05-01

Atrial fibrillation (AF) is a frequent problem of patients with pacemakers, and depends not only on disease but also on stimulation method. The aim of the study was to estimate the prevalence of AF before and after pacemaker implantation as well as to assess the influence of VVI and DDD cardiac pacing on onset of AF in patients with complete atrioventricularblock (AVB). We included 155 patients controlled between 2000 and 2008 in Pacemaker Clinic because of AVB III degree, treated with VVI or DDD pacemaker implantation. Information about the health status of the patients was gathered from medical documentation and analysis of clinical ambulatory electrocardiograms. The study group comprised of 68 women and 87 men, mean age 68.7 +/- 13.9 years during implantation. 69% of patients had VVI pacemaker. There were 72.3% of patients with sinus rhythm before pacemaker implantation. During follow-up 4 +/- 2.8 years in 19.6% cases onset of atrial fibrillation de novo was diagnosed (in 31.3% in VVI mode vs. 2.2% in DDD mode; p = 0.00014). Mean time to AF since implantation was approximately 2.5 years. In VVI group (21 persons) amounted 32.1 months, while in 1 patient with DDD pacemaker 18 months. Between group with AF after implantation and with sinus rhythm preserved there was no statistically significant difference in age or gender (p = 0.89512 and p = 0.1253, respectively). Prevalence of atrial fibrillation after pacemaker implantation increased to 40%. Atrial fibrillation is frequent in patients before and after pacemaker implantation, especially in patients stimulated in VVI mode. Major possibility of atrial fibrillation onset after pacemaker implantation should result in more attention during routine ECG examination.

Prevalence of E/A wave fusion and A wave truncation in DDD pacemaker patients with complete AV block under nominal AV intervals.

PubMed

Poller, Wolfram C; Dreger, Henryk; Schwerg, Marius; Melzer, Christoph

2015-01-01

Optimization of the AV-interval (AVI) in DDD pacemakers improves cardiac hemodynamics and reduces pacemaker syndromes. Manual optimization is typically not performed in clinical routine. In the present study we analyze the prevalence of E/A wave fusion and A wave truncation under resting conditions in 160 patients with complete AV block (AVB) under the pre-programmed AVI. We manually optimized sub-optimal AVI. We analyzed 160 pacemaker patients with complete AVB, both in sinus rhythm (AV-sense; n = 129) and under atrial pacing (AV-pace; n = 31). Using Doppler analyses of the transmitral inflow we classified the nominal AVI as: a) normal, b) too long (E/A wave fusion) or c) too short (A wave truncation). In patients with a sub-optimal AVI, we performed manual optimization according to the recommendations of the American Society of Echocardiography. All AVB patients with atrial pacing exhibited a normal transmitral inflow under the nominal AV-pace intervals (100%). In contrast, 25 AVB patients in sinus rhythm showed E/A wave fusion under the pre-programmed AV-sense intervals (19.4%; 95% confidence interval (CI): 12.6-26.2%). A wave truncations were not observed in any patient. All patients with a complete E/A wave fusion achieved a normal transmitral inflow after AV-sense interval reduction (mean optimized AVI: 79.4 ± 13.6 ms). Given the rate of 19.4% (CI 12.6-26.2%) of patients with a too long nominal AV-sense interval, automatic algorithms may prove useful in improving cardiac hemodynamics, especially in the subgroup of atrially triggered pacemaker patients with AV node diseases.

Dominant frequency increase rate predicts transition from paroxysmal to long-term persistent atrial fibrillation.

PubMed

Martins, Raphael P; Kaur, Kuljeet; Hwang, Elliot; Ramirez, Rafael J; Willis, B Cicero; Filgueiras-Rama, David; Ennis, Steven R; Takemoto, Yoshio; Ponce-Balbuena, Daniela; Zarzoso, Manuel; O'Connell, Ryan P; Musa, Hassan; Guerrero-Serna, Guadalupe; Avula, Uma Mahesh R; Swartz, Michael F; Bhushal, Sandesh; Deo, Makarand; Pandit, Sandeep V; Berenfeld, Omer; Jalife, José

2014-04-08

Little is known about the mechanisms underlying the transition from paroxysmal to persistent atrial fibrillation (AF). In an ovine model of long-standing persistent AF we tested the hypothesis that the rate of electric and structural remodeling, assessed by dominant frequency (DF) changes, determines the time at which AF becomes persistent. Self-sustained AF was induced by atrial tachypacing. Seven sheep were euthanized 11.5±2.3 days after the transition to persistent AF and without reversal to sinus rhythm; 7 sheep were euthanized after 341.3±16.7 days of long-standing persistent AF. Seven sham-operated animals were in sinus rhythm for 1 year. DF was monitored continuously in each group. Real-time polymerase chain reaction, Western blotting, patch clamping, and histological analyses were used to determine the changes in functional ion channel expression and structural remodeling. Atrial dilatation, mitral valve regurgitation, myocyte hypertrophy, and atrial fibrosis occurred progressively and became statistically significant after the transition to persistent AF, with no evidence for left ventricular dysfunction. DF increased progressively during the paroxysmal-to-persistent AF transition and stabilized when AF became persistent. Importantly, the rate of DF increase correlated strongly with the time to persistent AF. Significant action potential duration abbreviation, secondary to functional ion channel protein expression changes (CaV1.2, NaV1.5, and KV4.2 decrease; Kir2.3 increase), was already present at the transition and persisted for 1 year of follow up. In the sheep model of long-standing persistent AF, the rate of DF increase predicts the time at which AF stabilizes and becomes persistent, reflecting changes in action potential duration and densities of sodium, L-type calcium, and inward rectifier currents.

The prognostic significance of atrial fibrillation in heart failure with preserved ejection function: insights from KaRen, a prospective and multicenter study.

PubMed

Bosseau, Christian; Donal, Erwan; Lund, Lars H; Oger, Emmanuel; Hage, Camilla; Mulak, Geneviève; Daubert, Jean-Claude; Linde, Cecilia

2017-06-01

The prognostic value of atrial fibrillation (AF) in heart failure with preserved ejection fraction (HFPEF) remains controversial. We sought to study the prognostic value of AF in a prospective cohort and to characterize the HFPEF patients with AF. KaRen was a prospective, multicenter, international, observational study intended to characterize HFPEF; 538 patients presenting with an acute decompensated cardiac failure and a left ventricular EF > 45% were included. EKG and echocardiogram performed 4-8 week following the index hospitalization were analyzed in core centers. Clinical and echocardiographic characteristics of patients in sinus rhythm vs. with documented AF at enrolment (decompensated HF), upon their 4-8-week visit (in presumed stable clinical condition) and according to patients' cardiac history, were compared. The primary study endpoint was death from any cause or first hospitalization for decompensated heart failure (HF). A total of 413 patients (32% in AF) were analyzed, with a mean follow-up period of 28 months. The patients were primarily elderly individuals (mean age: 76.2 years), with a slight female predominance and a high prevalence of non-cardiovascular comorbidities. The baseline echocardiographic characteristics and the natriuretic peptide levels were indicative of a more severe heart condition among the patients with AF. However, the patients with AF exhibited a similar survival-free interval compared with the patients in sinus rhythm. In this elderly HFPEF population with a high prevalence of non-cardiovascular comorbidities, the presence of AF was not associated with a worse prognosis despite impaired clinical and echocardiographic features.ClinicalTrials.gov: NCT00774709.

Physiological response of cardiac tissue to bisphenol a: alterations in ventricular pressure and contractility

PubMed Central

Brooks, Daina; Chandra, Akhil; Jaimes, Rafael; Sarvazyan, Narine; Kay, Matthew

2015-01-01

Biomonitoring studies have indicated that humans are routinely exposed to bisphenol A (BPA), a chemical that is commonly used in the production of polycarbonate plastics and epoxy resins. Epidemiological studies have shown that BPA exposure in humans is associated with cardiovascular disease; however, the direct effects of BPA on cardiac physiology are largely unknown. Previously, we have shown that BPA exposure slows atrioventricular electrical conduction, decreases epicardial conduction velocity, and prolongs action potential duration in excised rat hearts. In the present study, we tested if BPA exposure also adversely affects cardiac contractile performance. We examined the impact of BPA exposure level, sex, and pacing rate on cardiac contractile function in excised rat hearts. Hearts were retrogradely perfused at constant pressure and exposed to 10−9-10−4 M BPA. Left ventricular developed pressure and contractility were measured during sinus rhythm and during pacing (5, 6.5, and 9 Hz). Ca2+ transients were imaged from whole hearts and from neonatal rat cardiomyocyte layers. During sinus rhythm in female hearts, BPA exposure decreased left ventricular developed pressure and inotropy in a dose-dependent manner. The reduced contractile performance was exacerbated at higher pacing rates. BPA-induced effects on contractile performance were also observed in male hearts, albeit to a lesser extent. Exposure to BPA altered Ca2+ handling within whole hearts (reduced diastolic and systolic Ca2+ transient potentiation) and neonatal cardiomyocytes (reduced Ca2+ transient amplitude and prolonged Ca2+ transient release time). In conclusion, BPA exposure significantly impaired cardiac performance in a dose-dependent manner, having a major negative impact upon electrical conduction, intracellular Ca2+ handing, and ventricular contractility. PMID:25980024

Block of Na(+)/Ca(2+) exchanger by SEA0400 in human right atrial preparations from patients in sinus rhythm and in atrial fibrillation.

PubMed

Christ, Torsten; Kovács, Peter P; Acsai, Karoly; Knaut, Michael; Eschenhagen, Thomas; Jost, Norbert; Varró, András; Wettwer, Erich; Ravens, Ursula

2016-10-05

The Na(+)/Ca(2+) exchanger (NCX) plays a major role in myocardial Ca(2+) homoeostasis, but is also considered to contribute to the electrical instability and contractile dysfunction in chronic atrial fibrillation (AF). Here we have investigated the effects of the selective NCX blocker SEA0400 in human right atrial cardiomyocytes from patients in sinus rhythm (SR) and AF in order to obtain electrophysiological evidence for putative antiarrhythmic activity of this new class of drugs. Action potentials were measured in right atrial trabeculae using conventional microelectrodes. Human myocytes were enzymatically isolated. Rat atrial and ventricular cardiomyocytes were used for comparison. Using perforated-patch, NCX was measured as Ni(2+)-sensitive current during ramp pulses. In ruptured-patch experiments, NCX current was activated by changing the extracellular Ca(2+) concentration from 0 to 1mM in Na(+)-free bath solution (100mM Na(+) intracellular, "Hilgemann protocol"). Although SEA0400 was effective in rat cardiomyocytes, 10µM did not influence action potentials and contractility, neither in SR nor AF. SEA0400 (10μM) also failed to affect human atrial NCX current measured with perforated patch. With the "Hilgemann protocol" SEA0400 concentration-dependently suppressed human atrial NCX current, and its amplitude was larger in AF than in SR cardiomyocytes. Our results confirm higher NCX activity in AF than SR. SEA0400 fails to block Ni(2+)-sensitive current in human atrial cells unless unphysiological conditions are used. We speculate that block of NCX with SEA0400 depends on intracellular Na(+) concentration. Copyright © 2016 Elsevier B.V. All rights reserved.

Box Isolation of Fibrotic Areas (BIFA): A Patient-Tailored Substrate Modification Approach for Ablation of Atrial Fibrillation.

PubMed

Kottkamp, Hans; Berg, Jan; Bender, Roderich; Rieger, Andreas; Schreiber, Doreen

2016-01-01

Catheter ablation strategies beyond pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF) are less well defined. Increasing clinical data indicate that atrial fibrosis is a critical common left atrial (LA) substrate in AF patients (pts). We applied a new substrate modification concept according to the individual fibrotic substrate as estimated from electroanatomic voltage mapping (EAVM) in 41 pts undergoing catheter ablation of AF. First, EAVM during sinus rhythm was done in redo cases of 10 pts with paroxysmal AF despite durable PVI. Confluent low-voltage areas (LVA) were found in all pts and were targeted with circumferential isolation, so-called box isolation of fibrotic areas (BIFA). This strategy led to stable sinus rhythm in 9/10 pts and was transferred prospectively to first procedures of 31 pts with nonparoxysmal AF. In 13 pts (42%), no LVA (<0.5 mV) were identified, and only PVI was performed. In 18 pts (58%), additional BIFA strategies were applied (posterior box in 5, anterior box in 7, posterior plus anterior box in 5, no box in 1 due to diffuse fibrosis). Mean follow-up was 12.5 ± 2.4 months. Single-procedure freedom from AF/atrial tachycardia was achieved in 72.2% of pts and in 83.3% of pts with 1.17 procedures/patient. In approximately 40% of pts with nonparoxysmal AF, no substantial LVA were identified, and PVI alone showed high success rate. In pts with paroxysmal AF despite durable PVI and in approximately 60% of pts with nonparoxysmal AF, individually localized LVA were identified and could be targeted successfully with the BIFA strategy. © 2015 Wiley Periodicals, Inc.

Electrocardiographic signal-averaging during atrial pacing and effect of cycle length on the terminal QRS in patients with and without inducible ventricular tachycardia.

PubMed

Kremers, M S; Black, W H; Lange, R; Wells, P J; Solo, M

1990-11-01

Electrocardiographic signal-averaging during sinus rhythm (61 to 99 beats/min) and atrial pacing (100 to 171 beats/min) were performed to determine the effect of heart rate on late potentials in 15 patients without (group 1) and 7 patients with (group 2) inducible sustained ventricular tachycardia (VT). In sinus rhythm (79 +/- 12 vs 77 +/- 12 beats/min, difference not significant), the duration of the low-amplitude signal less than 40 microV was longer in group 2 than group 1 (43 +/- 21 vs 26 +/- 8 ms, p = 0.034) and more patients had late potentials (57 vs 7%, p = 0.021), but QRS duration (121 +/- 32 vs 98 +/- 19 ms) and terminal voltage (33 +/- 33 vs 50 +/- 26 ms) were not significantly different. With atrial pacing in group 1 (128 +/- 16 beats/min), 3 patients developed a simultaneous decrease in terminal voltage and an increase in terminal QRS duration consistent with a late potential, but mean total and terminal durations were unchanged. Terminal voltage increased (50 +/- 26 to 59 +/- 40) but not significantly. With atrial pacing in group 2 (119 +/- 12 beats/min) all patients either had a late potential or developed a simultaneous decrease in terminal voltage and an increase in terminal QRS duration (p = 0.001 vs group 1). Root mean square (p = 0.001 vs group 1). Root mean square voltage decreased (33 +/- 23 to 22 +/- 23) and became significantly different from group 1 (p = 0.017). Mean QRS duration, root mean square terminal voltage and low-amplitude terminal QRS duration, however, were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial Ca2+ handling and cell-to-cell coupling, key factors in prevention of sudden cardiac death.

PubMed

Tribulova, Narcis; Seki, Shingo; Radosinska, Jana; Kaplan, Peter; Babusikova, Eva; Knezl, Vladimir; Mochizuki, Seibu

2009-12-01

Using whole-heart preparations, we tested our hypothesis that Ca(2+) handling is closely related to cell-to-cell coupling at the gap junctions and that both are critical for the development and particularly the termination of ventricular fibrillation (VF) and hence the prevention of sudden arrhythmic death. Intracellular free calcium concentration ([Ca(2+)](i)), ECG, and left ventricular pressure were continuously monitored in isolated guinea pig hearts before and during development of low K(+)-induced sustained VF and during its conversion into sinus rhythm facilitated by stobadine. We also examined myocardial ultrastructure to detect cell-to-cell coupling alterations. We demonstrated that VF occurrence was preceded by a 55.9% +/- 6.2% increase in diastolic [Ca(2+)](i), which was associated with subcellular alterations indicating Ca(2+) overload of the cardiomyocytes and disorders in coupling among the cells. Moreover, VF itself further increased [Ca(2+)](i) by 58.2% +/- 3.4% and deteriorated subcellular and cell-to-cell coupling abnormalities that were heterogeneously distributed throughout the myocardium. In contrast, termination of VF and its conversion into sinus rhythm was marked by restoration of basal [Ca(2+)](i), resulting in recovery of intercellular coupling linked with synchronous contraction. Furthermore, we have shown that hearts exhibiting lower SERCA2a (sarcoplasmic reticulum Ca(2+)-ATPase) activity and abnormal intercellular coupling (as in older guinea pigs) are more prone to develop Ca(2+) overload associated with cell-to-cell uncoupling than hearts with higher SERCA2a activity (as in young guinea pigs). Consequently, young animals are better able to terminate VF spontaneously. These findings indicate the crucial role of Ca(2+) handling in relation to cell-to-cell coupling in both the occurrence and termination of malignant arrhythmia.

Feasibility and radiation dose of high-pitch acquisition protocols in patients undergoing dual-source cardiac CT.

PubMed

Sommer, Wieland H; Albrecht, Edda; Bamberg, Fabian; Schenzle, Jan C; Johnson, Thorsten R; Neumaier, Klement; Reiser, Maximilian F; Nikolaou, Konstatin

2010-12-01

The objective of this study was to compare image quality and radiation dose between high-pitch and established retrospectively and prospectively gated cardiac CT protocols using an Alderson-Rando phantom and a set of patients. An anthropomorphic Alderson-Rando phantom equipped with thermoluminiscent detectors and a set of clinical patients underwent the following cardiac CT protocols: high-pitch acquisition (pitch 3.4), prospectively triggered acquisition, and retrospectively gated acquisition (pitch 0.2). For patients with sinus rhythm below 65 beats per minute (bpm), high-pitch protocol was used, whereas for patients in sinus rhythm between 65 and 100 bpm, prospective triggering was used. Patients with irregular heart rates or heart rates of ≥ 100 bpm, were examined using retrospectively gated acquisition. Evaluability of coronary artery segments was determined, and effective radiation dose was derived from the phantom study. In the phantom study, the effective radiation dose as determined with thermoluminescent detector (TLD) measurements was lowest in the high-pitch acquisition (1.21, 3.12, and 11.81 mSv, for the high-pitch, the prospectively triggered, and the retrospectively gated acquisition, respectively). There was a significant difference with respect to the percentage of motion-free coronary artery segments (99%, 87%, and 92% for high-pitch, prospectively triggered, and retrospectively gated, respectively (p < 0.001), whereas image noise was lowest for the high-pitch protocol (p < 0.05). High-pitch scans have the potential to reduce radiation dose up to 61.2% and 89.8% compared with prospectively triggered and retrospectively gated scans. High-pitch protocols lead to excellent image quality when used in patients with stable heart rates below 65 bpm.

Electrophysiologic studies in atrial fibrillation. Slow conduction of premature impulses: a possible manifestation of the background for reentry.

PubMed

Cosio, F G; Palacios, J; Vidal, J M; Cocina, E G; Gómez-Sánchez, M A; Tamargo, L

1983-01-01

Extrastimulus-induced intraatrial conduction delays were measured in 12 patients with documented episodes of atrial fibrillation (AF) by recording atrial electrograms at the high right atrium, His bundle region, and coronary sinus. Seventeen patients with and without heart disease, but without atrial arrhythmias served as the control group. During baseline-paced atrial rhythms, a conduction delay zone could be delineated, near the atrial effective refractory period, during which all extrastimuli produced conduction delays. When compared at the same paced cycle lengths (500 to 650 ms), the patients with AF had shorter atrial effective refractory periods (mean +/- standard deviation 206 +/- 24.1 versus 233 +/- 28.2 in control patients, p less than 0.02), wider conduction delay zones (79 +/- 21.7 ms versus 52 +/- 21 in control patients, p less than 0.01), and longer conduction delays both to the His bundle region (64 +/- 18.3 ms versus 35 +/- 21.7 in control patients, p less than 0.005) and the coronary sinus (76 +/- 18.9 ms versus 35 +/- 16.1 in control patients, p less than 0.001). Repetitive atrial responses were recorded in 6 patients with AF and in 9 control subjects. Sinus nodal function abnormalities were detected in 6 of the patients with fibrillation. Patients with AF had a higher tendency than control subjects to develop slow intraatrial conduction, as well as shorter effective refractory periods. Since both features would favor reentry, they may be the electrophysiologic manifestations of the abnormalities making these patients prone to atrial reentrant arrhythmias. Repetitive atrial responses were of no predictive value. Sinus nodal dysfunction was frequently found, but was not essential for the occurrence of AF.

Adapting detection sensitivity based on evidence of irregular sinus arrhythmia to improve atrial fibrillation detection in insertable cardiac monitors.

PubMed

Pürerfellner, Helmut; Sanders, Prashanthan; Sarkar, Shantanu; Reisfeld, Erin; Reiland, Jerry; Koehler, Jodi; Pokushalov, Evgeny; Urban, Luboš; Dekker, Lukas R C

2017-10-03

Intermittent change in p-wave discernibility during periods of ectopy and sinus arrhythmia is a cause of inappropriate atrial fibrillation (AF) detection in insertable cardiac monitors (ICM). To address this, we developed and validated an enhanced AF detection algorithm. Atrial fibrillation detection in Reveal LINQ ICM uses patterns of incoherence in RR intervals and absence of P-wave evidence over a 2-min period. The enhanced algorithm includes P-wave evidence during RR irregularity as evidence of sinus arrhythmia or ectopy to adaptively optimize sensitivity for AF detection. The algorithm was developed and validated using Holter data from the XPECT and LINQ Usability studies which collected surface electrocardiogram (ECG) and continuous ICM ECG over a 24-48 h period. The algorithm detections were compared with Holter annotations, performed by multiple reviewers, to compute episode and duration detection performance. The validation dataset comprised of 3187 h of valid Holter and LINQ recordings from 138 patients, with true AF in 37 patients yielding 108 true AF episodes ≥2-min and 449 h of AF. The enhanced algorithm reduced inappropriately detected episodes by 49% and duration by 66% with <1% loss in true episodes or duration. The algorithm correctly identified 98.9% of total AF duration and 99.8% of total sinus or non-AF rhythm duration. The algorithm detected 97.2% (99.7% per-patient average) of all AF episodes ≥2-min, and 84.9% (95.3% per-patient average) of detected episodes involved AF. An enhancement that adapts sensitivity for AF detection reduced inappropriately detected episodes and duration with minimal reduction in sensitivity. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Cardiology

Primary prevention of atrial fibrillation: does the atrial lead position influence the incidence of atrial arrhythmias in patients with sinus node dysfunction? Results from the PASTA Trial.

PubMed

Spitzer, Stefan G; Wacker, Petra; Gazarek, Steffen; Malinowski, Klaus; Schibgilla, Volker

2009-12-01

PASTA (pacing of the atria in sinus node disease) is a prospective and randomized trial, assessing the effect of different atrial lead positions on the atrial fibrillation (AF) incidence in patients with sinus node disease (SND). The atrial lead position is randomized to: (a) free right atrial wall, (b) right atrial appendage (RAA), (c) coronary sinus ostium (CS-Os), or (d) dual site right atrial pacing (CS-Os + RAA). The pacemakers (Vitatron Selection 9000 or Prevent AF, Vitatron B.V., Arnhem, The Netherlands) are programmed in DDDR 70 mode and the total follow-up duration is 24 months. To describe the atrial rhythm state, pacemaker-derived data (arrhythmia counter) were assessed for AF episodes. AF was considered as evident, if the AF burden (time in AF related to follow-up interval) was >1% (i.e., 15 min/d). Follow-up data after 24 months were evaluated. The analysis evaluates 142 patients (77 male, 74.5 +/- 7.8 years). There was no statistical significant difference with respect to the occurrence of AF between the four groups after 24 months (A: 36%; B: 38%, C: 32%, D: 48%). The percentage of atrial/ventricular pacing was in A: 78/76%, in B: 84/81%, in C: 70/65%, and in D: 79/69%. These differences were not significant. The evaluation of the AF burden >1% and the total AF burden after 24 months did not show differences in the incidence of AF in patients with dual chamber pacemaker therapy for SND. We were not able to demonstrate a significant influence of right atrial lead position on the incidence of AF recurrence.

Vitamin B12 treatment for sleep-wake rhythm disorders.

PubMed

Okawa, M; Mishima, K; Nanami, T; Shimizu, T; Iijima, S; Hishikawa, Y; Takahashi, K

1990-02-01

Vitamin B12 (VB12) was administered to two patients suffering for many years from different sleep-wake rhythm disorders. One patient was a 15-year-old blind girl suffering from a free-running sleep-wake rhythm (hypernychthemeral syndrome) with a period of about 25 h. In spite of repeated trials to entrain her sleep-wake cycle to the environmental 24-h rhythm, her free-running rhythm persisted for about 13 years. When she was 14 years old, administration of VB12 per os was started at the daily dose of 1.5 mg t.i.d. Shortly thereafter, her sleep-wake rhythm was entrained to the environmental 24-h rhythm, and her 24-h sleep-wake rhythm was maintained while she was on the medication. Within 2 months of the withholding of VB12, her free-running sleep-wake rhythm reappeared. The VB12 level in the serum was within the normal range both before and after treatment. The other patient was a 55-year-old man suffering from delayed sleep phase syndrome since 18 years of age. After administration of VB12 at the daily doses of 1.5 mg, his sleep-wake rhythm disorder was improved. The good therapeutic effect lasted for more than 6 months while he was on the medication.

Neurohumoral indicators of efficacy radiofrequency cardiac denervation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evtushenko, A. V., E-mail: ave@cardio-tomsk.ru; Evtushenko, V. V.; Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, Tomsk

In this study, we compared pre- and postoperative parameters of the cardiac sympathetic innervation. The aim of the study was to examine the approaches to evaluating the quality of radiofrequency (RF)-induced cardiac denervation by using non-invasive and laboratory methods. The study included 32 people with long-lasting persistent atrial fibrillation (AF). The patients were divided into 2 groups according to the objectives of the study: group 1 (main) - 21 patients with mitral valve diseases, which simultaneously with radiofrequency ablation (RFA) AF carried out on the effects of the paraganglionic nervous plexuses by C. Pappone (2004) and N. Doll (2008) schemes.more » The second group (control) contained 11 patients with heart diseases in sinus rhythm (the RF denervation not been performed). All patients, who underwent surgical treatment, were received examination of cardiac sympathetic tone by using {sup 123}I-MIBG. All of them made blood analysis from ascending aorta and coronary sinus to determine the level of norepinephrine and its metabolites before and after cardiac denervation. Data of radionuclide examination are correlating with laboratory data.« less

Circadian rhythms of gastrointestinal function are regulated by both central and peripheral oscillators

PubMed Central

Malloy, Jaclyn N.; Paulose, Jiffin K.; Li, Ye

2012-01-01

Circadian clocks are responsible for daily rhythms in a wide array of processes, including gastrointestinal (GI) function. These are vital for normal digestive rhythms and overall health. Previous studies demonstrated circadian clocks within the cells of GI tissue. The present study examines the roles played by the suprachiasmatic nuclei (SCN), master circadian pacemaker for overt circadian rhythms, and the sympathetic nervous system in regulation of circadian GI rhythms in the mouse Mus musculus. Surgical ablation of the SCN abolishes circadian locomotor, feeding, and stool output rhythms when animals are presented with food ad libitum, while restricted feeding reestablishes these rhythms temporarily. In intact mice, chemical sympathectomy with 6-hydroxydopamine has no effect on feeding and locomotor rhythmicity in light-dark cycles or constant darkness but attenuates stool weight and stool number rhythms. Again, however, restricted feeding reestablishes rhythms in locomotor activity, feeding, and stool output rhythms. Ex vivo, intestinal tissue from PER2::LUC transgenic mice expresses circadian rhythms of luciferase bioluminescence. Chemical sympathectomy has little effect on these rhythms, but timed administration of the β-adrenergic agonist isoproterenol causes a phase-dependent shift in PERIOD2 expression rhythms. Collectively, the data suggest that the SCN are required to maintain feeding, locomotor, and stool output rhythms during ad libitum conditions, acting at least in part through daily activation of sympathetic activity. Even so, this input is not necessary for entrainment to timed feeding, which may be the province of oscillators within the intestines themselves or other components of the GI system. PMID:22723262

Conversion of atrial fibrillation after levothyroxine in a dog with hypothyroidism and arterial thromboembolism.

PubMed

Chow, B; French, A

2014-05-01

A six-year-old female spayed mixed-breed dog was referred following a 3-week history of lameness and progressive neurological deficits in both hindlimbs, and a 1-week history of a cardiac arrhythmia. The dog was diagnosed with hypothyroidism, atrial fibrillation, myocardial dysfunction and arterial thromboembolism. Cardioversion occurred after 2 weeks of levothyroxine supplementation, with improved systolic function over time. To the authors' knowledge, this is the first case reported in the veterinary or human literature documenting hypothyroidism with persistent atrial fibrillation being converted to sinus rhythm with levothyroxine as sole therapy. © 2014 British Small Animal Veterinary Association.

Right atrial isolation associated with atrial septal closure in patients with atrial septal defect and chronic atrial fibrillation.

PubMed

Minzioni, G; Graffigna, A; Pagani, F; Vigano, M

1993-12-01

To restore sinus rhythm in the remaining heart chambers of six adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation, electrical, right atrial isolation associated with surgical correction of the defect was performed. All but one patient was free from atrial fibrillation without medication 2-25 months after operation. The isolated right atrial appendages showed intrinsic rhythmical activity in five patients and no electrical activity in one. Right atrial isolation is a safe and effective procedure that abolishes atrial fibrillation in patients with arrhythmia after surgical correction of atrial septal defect.

[Current ideas of a complex relationship between atrial fibrillation and ischemic heart disease and of optimum tactics for anticoagulant therapy to prevent embolism in systemic circulation].

PubMed

Golshmid, M V; Gilyarevskiy, S R; Kuzmina, I M; Sinitsina, I I

The article discusses the issue of searching for optimum oral anticoagulants to prevent thrombosis and embolism induced by heart disease both in patients with atrial fibrillation and sinus rhythm. A complex bidirectional relationship between atrial fibrillation and coronary atherosclerosis is considered along with possible mechanisms for development of myocardial infarction in patients with atrial fibrillation. The authors provided evidence-based data which can be used in selecting an anticoagulant for prevention of heart disease induced thrombosis and embolism taking into account both the efficacy and safety established in randomized clinical studies.

Recurrent infarctions due to a dome-shaped pannus above the mitral valve prosthesis

PubMed Central

Inoue, Yoshito; Suzuki, Satoru

2016-01-01

This report describes a unique case of a 56-year-old female who suffered from recurrent stroke after double mechanical valve replacement. During the four years after the surgery, she remained in normal sinus rhythm, received adequate anticoagulation therapy, and no apparent left atrial thrombus was detected. She underwent redo surgery to prevent further stroke after fourth instance of cerebral infarction. Intraoperative findings revealed a ‘dome-shaped’ pannus formation covering the sewing ring of the mitral prosthesis circumferentially, probably leading to clot formation and repeated infarctions. She has been stroke free for three years after pannus resection. PMID:26904241

Inappropriate ICD discharges due to "triple counting" during normal sinus rhythm.

PubMed

Khan, Ejaz; Voudouris, Apostolos; Shorofsky, Stephen R; Peters, Robert W

2006-11-01

To describe the clinical course of a patient with multiple ICD shocks in the setting of advanced renal failure and hyperkalemia. The patient was brought to the Electrophysiology Laboratory where the ICD was interrogated. The patient was found to be hyperkalemic (serum potassium 7.6 mg/dl). Analysis of stored intracardiac electrograms from the ICD revealed "triple counting" (twice during his QRS complex and once during the T wave) and multiple inappropriate shocks. Correction of his electrolyte abnormality normalized his electrogram and no further ICD activations were observed. Electrolyte abnormalities can distort the intracardiac electrogram in patients with ICD's and these changes can lead to multiple inappropriate shocks.

Season-dependent effects of photoperiod and temperature on circadian rhythm of arylalkylamine N-acetyltransferase2 gene expression in pineal organ of an air-breathing catfish, Clarias gariepinus.

PubMed

Singh, Kshetrimayum Manisana; Saha, Saurav; Gupta, Braj Bansh Prasad

2017-08-01

Arylalkylamine N-acetyltransferase (AANAT) activity, aanat gene expression and melatonin production have been reported to exhibit prominent circadian rhythm in the pineal organ of most species of fish. Three types of aanat genes are expressed in fish, but the fish pineal organ predominantly expresses aanat2 gene. Increase and decrease in daylength is invariably associated with increase and decrease in temperature, respectively. But so far no attempt has been made to delineate the role of photoperiod and temperature in regulation of the circadian rhythm of aanat2 gene expression in the pineal organ of any fish with special reference to seasons. Therefore, we studied effects of various lighting regimes (12L-12D, 16L-8D, 8L-16D, LL and DD) at a constant temperature (25°C) and effects of different temperatures (15°, 25° and 35°C) under a common photoperiod 12L-12D on circadian rhythm of aanat2 gene expression in the pineal organ of Clarias gariepinus during summer and winter seasons. Aanat2 gene expression in fish pineal organ was studied by measuring aanat2 mRNA levels using Real-Time PCR. Our findings indicate that the pineal organ of C. gariepinus exhibits a prominent circadian rhythm of aanat2 gene expression irrespective of photoperiods, temperatures and seasons, and the circadian rhythm of aanat2 gene expression responds differently to different photoperiods and temperatures in a season-dependent manner. Existence of circadian rhythm of aanat2 gene expression in pineal organs maintained in vitro under 12L-12D and DD conditions as well as a free running rhythm of the gene expression in pineal organ of the fish maintained under LL and DD conditions suggest that the fish pineal organ possesses an endogenous circadian oscillator, which is entrained by light-dark cycle. Copyright © 2017 Elsevier B.V. All rights reserved.

Cardiac arrhythmias during aerobatic flight and its simulation on a centrifuge.

PubMed

Zawadzka-Bartczak, Ewelina K; Kopka, Lech H

2011-06-01

It is well known that accelerations during centrifuge training and during flight can provoke cardiac arrhythmias. Our study was designed to investigate both the similarities and differences between heart rhythm disturbances during flights and centrifuge tests. There were 40 asymptomatic, healthy pilots who performed two training flights and were also tested in a human centrifuge according to a program of rapid onset rate acceleration (ROR) and of centrifuge simulation of the actual acceleration experienced in flight (Simulation). During the flight and centrifuge tests ECG was monitored with the Holter method. ECG was examined for heart rhythm changes and disturbances. During flights, premature ventricular contractions (PVCs) were found in 25% of the subjects, premature supraventricular contractions (PSVCs) and PVCs with bigeminy in 5%, and pairs of PVCs in 2.5% of subjects. During the centrifuge tests, PVCs were experienced by 45% of the subjects, PSVCs and pairs of PVCs by 7.5%, and PVCs with bigeminy by 2.5%. Sinus bradycardia was observed during flights and centrifuge tests in 7.5% of subjects. Comparative evaluation of electrocardiographic records in military pilots during flights and centrifuge tests demonstrated that: 1) there were no clinically significant arrhythmias recorded; and 2) the frequency and kind of heart rhythm disturbances during aerobatic flight and its simulation on a centrifuge were not identical and did not occur repetitively in the same persons during equal phases of the tests.

An easy-to-use technique to characterize cardiodynamics from first-return maps on ΔRR-intervals

NASA Astrophysics Data System (ADS)

Fresnel, Emeline; Yacoub, Emad; Freitas, Ubiratan; Kerfourn, Adrien; Messager, Valérie; Mallet, Eric; Muir, Jean-François; Letellier, Christophe

2015-08-01

Heart rate variability analysis using 24-h Holter monitoring is frequently performed to assess the cardiovascular status of a patient. The present retrospective study is based on the beat-to-beat interval variations or ΔRR, which offer a better view of the underlying structures governing the cardiodynamics than the common RR-intervals. By investigating data for three groups of adults (with normal sinus rhythm, congestive heart failure, and atrial fibrillation, respectively), we showed that the first-return maps built on ΔRR can be classified according to three structures: (i) a moderate central disk, (ii) a reduced central disk with well-defined segments, and (iii) a large triangular shape. These three very different structures can be distinguished by computing a Shannon entropy based on a symbolic dynamics and an asymmetry coefficient, here introduced to quantify the balance between accelerations and decelerations in the cardiac rhythm. The probability P111111 of successive heart beats without large beat-to-beat fluctuations allows to assess the regularity of the cardiodynamics. A characteristic time scale, corresponding to the partition inducing the largest Shannon entropy, was also introduced to quantify the ability of the heart to modulate its rhythm: it was significantly different for the three structures of first-return maps. A blind validation was performed to validate the technique.

[Estimation of the atrioventricular time interval by pulse Doppler in the normal fetal heart].

PubMed

Hamela-Olkowska, Anita; Dangel, Joanna

2009-08-01

To assess normative values of the fetal atrioventricular (AV) time interval by pulse-wave Doppler methods on 5-chamber view. Fetal echocardiography exams were performed using Acuson Sequoia 512 in 140 singleton fetuses at 18 to 40 weeks of gestation with sinus rhythm and normal cardiac and extracardiac anatomy. Pulsed Doppler derived AV intervals were measured from left ventricular inflow/outflow view using transabdominal convex 3.5-6 MHz probe. The values of AV time interval ranged from 100 to 150 ms (mean 123 +/- 11.2). The AV interval was negatively correlated with the heart rhythm (p<0.001). Fetal heart rate decreased as gestation progressed (p<0.001). Thus, the AV intervals increased with the age of gestation (p=0.007). However, in the same subgroup of the fetal heart rate there was no relation between AV intervals and gestational age. Therefore, the AV intervals showed only the heart rate dependence. The 95th percentiles of AV intervals according to FHR ranged from 135 to 148 ms. 1. The AV interval duration was negatively correlated with the heart rhythm. 2. Measurement of AV time interval is easy to perform and has a good reproducibility. It may be used for the fetal heart block screening in anti-Ro and anti-La positive pregnancies. 3. Normative values established in the study may help obstetricians in assessing fetal abnormalities of the AV conduction.

Twenty-four hour Holter monitoring in finishing cattle housed outdoors.

PubMed

Frese, D A; Thomason, J D; Reinhardt, C; Bartle, S; Rethorst, D; Loneragan, G H; Thomson, D

2017-04-01

Atrial premature complexes have been reported to be the most common arrhythmia in cattle and is suspected to be secondary to systemic disease, especially gastrointestinal disease. In order to properly identify pathologic arrhythmia in cattle, the normal rhythm and arrhythmia prevalence should be defined. The objective of this study was to determine the normal heart rate, rhythm, number of ventricular premature complexes (VPCs), and atrial premature complexes (APCs) in unrestrained Angus steers. Twenty-seven client owned steers with unremarkable physical examinations and serum biochemical analyses were used. Twenty-four hour Holter monitors, attached by a custom-made harness, were retrospectively evaluated. Three lead electrocardiographic registrations of good quality and normal sinus rhythm were obtained from all steers in the study. The mean heart rate was 66.8 bpm ± 16.4 bpm. Ventricular premature complexes were rare (noted in 14.8% of steers), and APCs were common (noted in 85% of the steers). Simple second degree AV block was observed in 18.5% of the steers. In summary, healthy steers have rare single VPCs, although it is possible for an individual animal to have apparent more frequent VPCs. Mean heart rate varies with a diurnal pattern similar to other species. Atrial premature complexes are the most prevalent abnormality observed in feedlot steers. Copyright © 2016 Elsevier B.V. All rights reserved.

Daily rhythm of salivary IL-1ß, cortisol and melatonin in day and night workers.

PubMed

Reinhardt, Érica Lui; Fernandes, Pedro Augusto Carlos Magno; Markus, Regina Pekelmann; Fischer, Frida Marina

2012-01-01

Shiftwork-induced sleep deprivation and circadian disruption probably leads to an increase in the production of cytokines and dysregulation of innate immune system, respectively. This project aims evaluating changes in salivary IL-1 beta, cortisol, and melatonin in night workers. Method. Two day and three night healthy workers participated in this study. Sleep was evaluated by actimetry and activity protocols. Saliva was collected at waking and bedtime the last workday and the following two days-off and was analyzed by ELISA. Results. Neither sleep duration nor efficiency showed any association with salivary IL-1beta. IL-1beta levels were higher at waking than at bedtime during working days for all workers, but only one day and one night-worker maintained this pattern and hormone rhythms during days off. For this night worker, melatonin levels were shifted to daytime. A second one presented clear alterations in IL-1beta and hormone rhythms on days-off. Conclusions. Our preliminary results suggest that night work can disturb the variation pattern of salivary IL-1beta. No association of this variation with sleep was observed. It seems that disruption in hormone rhythms interfere with salivary IL-1beta production. IL- 1beta production pattern seems to be maintained when rhythms are present, in spite of a shift in melatonin secretion.

Simultaneous assessment of contact pressure and local electrical coupling index using robotic navigation.

PubMed

Dello Russo, Antonio; Fassini, Gaetano; Casella, Michela; Bologna, Fabrizio; Al-Nono, Osama; Colombo, Daniele; Biagioli, Viviana; Santangeli, Pasquale; Di Biase, Luigi; Zucchetti, Martina; Majocchi, Benedetta; Marino, Vittoria; Gallinghouse, Joseph J; Natale, Andrea; Tondo, Claudio

2014-06-01

Contact with cardiac tissue is a determinant of lesion efficacy during atrial fibrillation (AF) ablation. The Sensei®X Robotic Catheter System (Hansen Medical, CA) has been validated for contact force sensing. The electrical coupling index (ECI) from the EnSite Contact™ system (St. Jude Medical, MN) has been validated as an indicator of tissue contact. We aimed at analyzing ECI behavior during radiofrequency (RF) pulses maintaining a stable contact through the robotic navigation contact system. In 15 patients (age, 59 ± 12) undergoing AF ablation, pulmonary vein (PV) isolation was guided by the Sensei®X System, employing the Contact™ catheter. During the procedure, we assessed ECI changes associated with adequate contact based on the IntelliSense® force-sensing technology (Hansen Medical, CA. Baseline contact (27 ± 8 g/cm(2)) ECI value was 99 ± 13, whereas ECI values in a noncontact site (0 g/cm(2)) and in a light contact site (1-10 g/cm(2)) were respectively 66 ± 12 and 77 ± 10 (p < 0.0001). Baseline contact ECI values were not different depending on AF presentation (paroxysmal AF, 98 ± 9; persistent AF, 100 ± 9) or on cardiac rhythm (sinus rhythm, 97 ± 7; AF,101 ± 10). In all PVs, ECI was significantly reduced during and after ablation (ECI during RF, 56 ± 15; ECI after RF, 72 ± 16; p < 0.001). A mean reduction of 32.2% during RF delivery and 25.4% immediately after RF discontinuation compared with baseline ECI was observed. Successful PV isolation is associated with a significant decrease in ECI of at least 20 %. This may be used as a surrogate marker of effective lesion in AF ablation.

Investigation of the effects of intravenous magnesium sulphate on cardiac rhythm in acute myocardial infarction.

PubMed Central

Roffe, C.; Fletcher, S.; Woods, K. L.

1994-01-01

OBJECTIVE--To examine the effect of doubling serum magnesium concentration on the incidence of arrhythmias in patients with suspected acute myocardial infarction. DESIGN--Randomised double blind clinical trial. SETTING--Coronary care unit of a teaching hospital. PATIENTS--Clinical data were collected on 2316 randomised patients with suspected acute myocardial infarction. Holter monitoring was performed in a subgroup of 70 patients and analysed in 48 patients in whom acute myocardial infarction was confirmed. INTERVENTIONS--By random allocation, patients received either an intravenous loading dose of 8 mmol magnesium sulphate over five minutes plus 65 mmol over the next 24 hours, or equal volumes of saline. MAIN OUTCOME MEASURES--(a) Clinically documented arrhythmias; (b) use of antiarrhythmic treatments, cardioversion, and insertion of a pacemaker; (c) incidence of all abnormal rhythms during Holter monitoring. RESULTS--In the main trial the incidence of rhythm disturbance while in the coronary care unit (expressed as the odds ratio (OR) for magnesium: placebo and its 95% confidence interval) was not significantly different between treatment groups for ventricular fibrillation (OR 0.74; 0.46 to 1.20), ventricular tachycardia (OR 0.87; 0.63 to 1.20), supraventricular tachycardia (OR 0.69; 0.38 to 1.26), atrial fibrillation (OR 0.92; 0.69 to 1.23), or heart block of any degree (OR 1.17; 0.83 to 1.65). Sinus bradycardia was significantly more common in the magnesium group (OR 1.38; 1.03 to 1.85; p = 0.02). These findings were corroborated by the use of treatments for rhythm disturbance and the data from Holter monitoring. CONCLUSION--The regimen of intravenous magnesium sulphate used here had no significant effect on arrhythmia in acute myocardial infarction. The reduction in mortality that has been shown with this form of treatment is not attributable to suppression of life threatening rhythm disturbances. PMID:8130021

Using Intracardiac Vectorcardiographic Loop for Surface ECG Synthesis

NASA Astrophysics Data System (ADS)

Kachenoura, A.; Porée, F.; Hernández, A. I.; Carrault, G.

2008-12-01

Current cardiac implantable devices offer improved processing power and recording capabilities. Some of these devices already provide basic telemonitoring features that may help to reduce health care expenditure. A challenge is posed in particular for the telemonitoring of the patient's cardiac electrical activity. Indeed, only intracardiac electrograms (EGMs) are acquired by the implanted device and these signals are difficult to analyze directly by clinicians. In this paper, we propose a patient-specific method to synthesize the surface electrocardiogram (ECG) from a set of EGM signals, based on a 3D representation of the cardiac electrical activity and principal component analysis (PCA). The results, in the case of sinus rhythm, show a correlation coefficient between the real ECG and the synthesized ECG of about 0.85. Moreover, the application of the proposed method to the patients who present an abnormal heart rhythm exhibits promising results, especially for characterizing the bundle branch blocs. Finally, in order to evaluate the behavior of our procedure in some practical situations, the quality of the ECG reconstruction is studied as a function of the number of EGM electrodes provided by the CIDs.

Terminal echocardiographic findings during death process in man and dogs.

PubMed

Wang, F S; Lien, W P; Fong, T E

1991-01-01

Serial echocardiographic imaging was performed to assess terminal mechanical changes of cardiac chambers and valves, as well as sequential echocardiographic features of blood stasis, inside the heart after mechanical asystole in 7 hospitalized adults who died without apparent cardiac disease and in 7 experimental dogs sacrificed by a means of asphyxia. Marked reduction of wall motion became manifest shortly after the electrocardiograms had generated into a slow junctional rhythm with intraventricular conduction defect, an idioventricular rhythm, or an extreme sinus bradycardia. Total cessation of cardiac wall and valve motion followed; the aortic valve remained closed, with mitral and tricuspid valves semiopen after total cardiac asystole. Liquid whole blood inside the heart became echogenic shortly before mechanical asystole had approached, and homogenous echogenicity usually first appeared on the right side of the heart. As the death process progressed and total asystole persisted, the acoustic intensity of the intracavitary echoes increased, tending to form amorphous masses, with some showing rather well-defined borders. Such echocardiographic features were noted to indicate red thrombi in experimental dogs. The cardiac dimensions (left ventricle and aorta) decreased after total cardiac asystole.

Hemodynamic instability after pulmonary veins isolation in a patient with dual chamber pacemaker

PubMed Central

Kiuchi, Márcio Galindo; Lobato, Guilherme Miglioli; Chen, Shaojie

2017-01-01

Abstract Introduction: The standard treatment of sinus node dysfunction (SND) is the pacemaker implantation, and the ideal methodology for the management of atrial fibrillation (AF) is rhythm control, but this is sometimes very hard to accomplish. For such actions, complete isolation of all pulmonary veins (PVI) is currently widely accepted as the best endpoint. Case Presentation: In this case, we report a female patient, 81 years old, with controlled hypertension, without coronary artery disease, bearer of bilateral knee replacement, and dual chamber pacemaker implanted 1.5 years ago owing to sinus node disease, presenting the following symptoms: presyncope episodes associated with sustained irregular palpitation tachycardia. The evaluation of the pacemaker-recorded episodes of atrial fibrillation, the echocardiogram-presented normal systolic function and measurements, as well as the resting myocardial scintigraphy and with drug use did not demonstrate ischemia and/or fibrosis. The patient was in use of valsartan 320 mg daily, amlodipine 10 mg daily, sotalol hydrochloride 120 mg 2 times daily, and dabigatran 110 mg 2 times daily. At the end of the PVI, the patient presented hemodynamic instability, with a decrease in heart rate to 30 bpm and invasive arterial blood pressure to 60/30 mmHg. The pericardial puncture was quickly carried out with the possibility of cardiac tamponade as the first hypothesis, but no pericardial effusion was found. Next, we detected acute capture loss from the ventricular pacemaker lead, unvarying with high voltage and pulse width, even with stable impedance, sense and keeping the same position visualized by fluoroscopy. And there was soon afterwards induction of sustained ventricular tachycardia degenerating to spontaneous ventricular fibrillation. Electrical cardioversion-defibrillation was performed with 200J, and the sinus rhythm was reestablished, but there was a dead short, and the pacemaker generator was burned and disabled. Conclusions: So, we can speculate that application of atrial radiofrequency for PVI diffused through the tissues, affecting in some way the tip of the ventricular electrode, causing a microlesion in this structure and making it impossible to capture the right ventricle by the pacemaker. As we cannot see it, we can call it of phantom injury of the ventricular lead. PMID:28562571

Hemodynamic instability after pulmonary veins isolation in a patient with dual chamber pacemaker: The phantom injury of the ventricular lead.

PubMed

Kiuchi, Márcio Galindo; Lobato, Guilherme Miglioli; Chen, Shaojie

2017-06-01

The standard treatment of sinus node dysfunction (SND) is the pacemaker implantation, and the ideal methodology for the management of atrial fibrillation (AF) is rhythm control, but this is sometimes very hard to accomplish. For such actions, complete isolation of all pulmonary veins (PVI) is currently widely accepted as the best endpoint. In this case, we report a female patient, 81 years old, with controlled hypertension, without coronary artery disease, bearer of bilateral knee replacement, and dual chamber pacemaker implanted 1.5 years ago owing to sinus node disease, presenting the following symptoms: presyncope episodes associated with sustained irregular palpitation tachycardia. The evaluation of the pacemaker-recorded episodes of atrial fibrillation, the echocardiogram-presented normal systolic function and measurements, as well as the resting myocardial scintigraphy and with drug use did not demonstrate ischemia and/or fibrosis. The patient was in use of valsartan 320 mg daily, amlodipine 10 mg daily, sotalol hydrochloride 120 mg 2 times daily, and dabigatran 110 mg 2 times daily. At the end of the PVI, the patient presented hemodynamic instability, with a decrease in heart rate to 30 bpm and invasive arterial blood pressure to 60/30 mmHg. The pericardial puncture was quickly carried out with the possibility of cardiac tamponade as the first hypothesis, but no pericardial effusion was found. Next, we detected acute capture loss from the ventricular pacemaker lead, unvarying with high voltage and pulse width, even with stable impedance, sense and keeping the same position visualized by fluoroscopy. And there was soon afterwards induction of sustained ventricular tachycardia degenerating to spontaneous ventricular fibrillation. Electrical cardioversion-defibrillation was performed with 200J, and the sinus rhythm was reestablished, but there was a dead short, and the pacemaker generator was burned and disabled. So, we can speculate that application of atrial radiofrequency for PVI diffused through the tissues, affecting in some way the tip of the ventricular electrode, causing a microlesion in this structure and making it impossible to capture the right ventricle by the pacemaker. As we cannot see it, we can call it of phantom injury of the ventricular lead.

Circadian intraocular pressure rhythms in athletic horses under different lighting regime.

PubMed

Bertolucci, Cristiano; Giudice, Elisabetta; Fazio, Francesco; Piccione, Giuseppe

2009-02-01

The present study was undertaken to investigate the existence of intraocular pressure (IOP) rhythms in athletic thoroughbred horses maintained under a 24 h cycle of light and darkness (LD) or under constant light (LL) or constant dark (DD) conditions. We identified an IOP circadian rhythm that is entrained to the 24 h LD cycle. IOP was low during the dark phase and high during the light phase, with a peak at the end of the light phase (ZT10). The circadian rhythm of IOP persisted in DD (with a peak at CT9.5), demonstrating an endogenous component in IOP rhythm. As previously shown in other mammalian species, horse IOP circadian rhythmicity was abolished in LL. Because tonometry is performed in horses for the diagnosis of ophthalmologic diseases, such as glaucoma or anterior uveitis, the daily variation in IOP must be taken into account in clinical practice to properly time tests and to interpret clinical findings.

Incidence of pericardial effusion after left atrial appendage closure: The impact of underlying heart rhythm. data from the EWOLUTION study.

PubMed

Schmidt, Boris; Betts, Timothy R; Sievert, Horst; Bergmann, Martin W; Kische, Stephan; Pokushalov, Evgeny; Schmitz, Thomas; Meincke, Felix; Mazzone, Patrizio; Stein, Kenneth M; Ince, Hüseyin; Boersma, Lucas V A

2018-05-03

Pericardial effusion/tamponade (PE/PT) is a rare but serious complication following left atrial appendage closure (LAAC). It may be speculated that LAA contraction during sinus rhythm (SR) exerts mechanical force on the device that eventually leads to PE. We sought to determine the incidence and predictors of PE following LAAC using Watchman with special emphasis on the underlying heart rhythm during implant. From 47 centers in 13 European countries 1020 patients underwent LAAC and data on baseline rhythm were available from 1010 patients (mean age 73 ± 9 years, 60% male, median CHA2DS2-VASc = 4). Data were collected via electronic case report forms. A Cox-proportional hazard model was calculated adjusting for multiple variables: age, gender, number of recaptures and device oversizing. During implant, 41% and 59% of patients were in SR and atrial fibrillation (AF), respectively. PE/PT rate was significantly lower in patients implanted during AF at day 30 post implant (n = 1; 0.2% versus n = 6; 1.5%; p = 0.02). No PE requiring intervention occurred in the AF group compared to 5 events (1.2%) in the SR group (p = 0.01). While univariate analysis identified SR and gender as predictors for PE/tamponade, multivariate analysis only showed a statistical trend for both variables. The overall incidence of PE/PT was very low after LAAC using Watchman. Although SR was not identified as an independent predictor of PE/PT, all events requiring intervention occurred in patients with SR. It may be advisable to perform an extended echocardiographic follow-up in that patient population. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Cardioversion and subsequent quality of life and natural history of atrial fibrillation.

PubMed

Pokorney, Sean D; Kim, Sunghee; Thomas, Laine; Fonarow, Gregg C; Kowey, Peter R; Gersh, Bernard J; Mahaffey, Kenneth W; Peterson, Eric D; Piccini, Jonathan P

2017-03-01

Cardioversion is a class I procedure for patients with symptomatic atrial fibrillation (AF) pursuing rhythm control. There are few contemporary reports on quality of life and outcomes after cardioversion. Using the nationwide prospective ORBIT-AF registry, cardioversion patients were propensity matched 3:1 to noncardioverted patients and Cox proportional hazards modeling evaluated hospitalization at 1 year in those with and without cardioversion. Cardiovascular outcomes, AF progression, and quality of life were evaluated for the matched cohorts with and without cardioversion. Among 9,642 patients, 817 patients (8%) underwent 906 cardioversions during a median follow-up of 12 (interquartile range 6-18) months. Among matched cardioverted and noncardioverted patients, 1-year cardiovascular hospitalization rates were 43% vs 21% (adjusted hazard ratio 2.2, 95% CI 1.8-2.8, P<.001), and sinus rhythm at both first and second follow-ups was 36% vs 27% (P=.042), respectively. Findings were similar among first-time cardioversion patients. Matched cardioversion patients did not exhibit greater symptom improvement (34% vs 42%) or less symptomatic progression (15% vs 4%) by European Heart Rhythm Association scores. Cardioversion was associated with AF progression with an odds ratio of 1.6 (95% CI 1.2-2.2, P=.001) after cardioversion and 2.7 (P<.001) after first cardioversion vs matched noncardioversion patients. After cardioversion, only 18% of patients not previously on an antiarrhythmic started one, less than 5% underwent ablation, and 22% stopped their antiarrhythmic. Cardioversion was not associated with improved AF-related quality of life or less progression. Many patients who undergo cardioversion do not receive adjunctive rhythm control therapies. These findings may help to better inform therapeutic decision making. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The change in NT-pro-BNP and post-PTMC echocardiography parameters in patients with mitral stenosis. A pilot study.

PubMed

Safi, Morteza; Bayat, Fariba; Ahmadi, Zahra; Shekarchizadeh, Masood; Khaheshi, Isa; Naderian, Mohammadreza

2017-06-01

The change in the level of NT-pro-BNP (N-terminal-pro-Brain Natriuretic Peptide) is now considered as a reflection of the hemodynamic alterations and its circulatory reductions reported early after successful PTMC (percutaneous transvenous mitral commissurotomy). The present study aims to assess the change in the level of NT-pro BNP following PTMC in patients with mitral stenosis and also to determine the association between circulatory NT-pro-BNP reduction and post-PTMC echocardiography parameters. Twenty five symptomatic consecutive patients with severe MS undergoing elective PTMC were prospectively enrolled. All patients underwent echocardiography before and also 24 to 48 hours after PTMC. Peripheral blood samples were taken for measurement of NT-pro-BNP before as well as 24 to 48 hours after PTMC. The patients were also classified in group with normal sinus rhythm or having atrial fibrillation (AF) based on their 12-lead electrocardiogram. It was shown a significant decrease in the parameters of PPG (Peak Pressure Gradient), MPG (Mean Pressure Gradient), PHT (Pressure Half Time), PAP (Pulmonary Arterial Pressure), LAV (Left Atrial Volume), and also a significant increase in MVA (Mitral Valve Area) RVS (Right Ventricular S velocity), and strains of lateral, septal, inferior and anterior walls of LA following PTMC. The mean LVEF remained unchanged after PTMC. The mean NT-pro-BNP before PTMC was 309.20 ± 17.97 pg/lit that significantly diminished after PTMC to 235.72 ± 22.46 pg/lit (p = 0.009). Among all echocardiography parameters, only MPG was positively associated with the change in NT-pro-BNP after PTMC. Comparing the change in echocardiography indices between the patients with normal rhythm and those with AF, lower change in PAP was shown in the group with AF. However, more change in the level of NT-pro-BNP after PTMC was shown in the patients with AF compared to those without this arrhythmia. PTMC procedure leads to reduce the level of NT-pro-BNP. The change in NT-pro-BNP is an indicator for change in MS severity indicated by decreasing MPG parameter. Lower change in PAP as well as higher change in NT-pro-BNP is predicted following PTMC in the group with AF compared to those with normal sinus rhythm.

[Effects of grain-sized moxibustion from 7 am to 9 am on circadian rhythm of inflammatory factor IL-6 in rats with rheumatoid arthritis].

PubMed

Ma, Wenbin; Liu, Xuguang; Qin, Yong; Zhou, Haiyan; Yang, Xin

2016-04-01

To explore the rhythm regulatory mechanism of interleukin-6 (IL-6) in the process of moxibustion for rheumatoid arthritis (RA). A total of 144 Sprague-Dawley (SD) rats were randomly divided into a blank group, a model group, a moxibustion group, a sham operation group, an operation group, an operation+moxibustion group, 24 rats in each one. Each group was divided into 4 time points (0:00 am, 6:00' am, 12:00 am, 6:00 pm), 6 rats in each time point. The Light-Dark 12 : 12 was given in all rats for light-dark cycle. Except the blank group, rats in the remaining groups were treated with intracutaneous injection of freund's complete adjuvant at right-side foot to establish the model of RA. After the model establishment, bilateral adrenal, glands were removed in the operation group and operation + moxibustion group, while those in the sham operation group were not removed with identical operation procedure. Rats in the moxibustion group and operation + moxibustion group were treated with grain-sized moxibustion from 7:00 am to 9:00 am at "Shenshu" (BL 23) and "Zusanli" (ST 36) once everyday, 6 times were taken as one session and 3 sessions were required tatclly, while rats in the remaining groups received identical fixation without moxibustion. The general health state and foot volume of rats were measured before model establishment, after establishment and after treatment. After treatment, rats were sacrificed at each time point to collect the blood sample and measure the content of IL-6 by using enzymne-immunoassay method. Compared with the blank group, the foot swelling in the model group was obviously increased (P<0. 05); the IL-6 maintained circadian rhythm (P<0. 05), but the peak phase had a backward trend, famplitude had an increased trend and the median was significantly lifted (P<0. 05). Compared with model group, !the foot swelling in the moxibustion group was obviously decreased (P<0. 05); the IL-6 maintained circadian. rhythm (P<0. 05), and the peak phase had a forward trend, amplitude had a decreased trend and the median was significantly reduced (P<0. 05). Compared with the moxibustion group, the foot swelling in the operation--moxibustion group was obviously increased (P < 0.05); the IL-6 maintained circadian rhythm (P < 0.5), but the peak phase moved forwrd, and the median was significantly elevated (P < 0.05). The IL-6 in plasma maintains significant pathological circadian rhythm in RA rats; with the complete hypothalamic-pituitary-adrenal axis, moxibustion is likely to regulate the circadian rhythm of IL-6 to play an important role of anti-inflammatory effect in RA rats.

Left versus right atrial difference in dominant frequency, K(+) channel transcripts, and fibrosis in patients developing atrial fibrillation after cardiac surgery.

PubMed

Swartz, Michael F; Fink, Gregory W; Lutz, Charles J; Taffet, Steven M; Berenfeld, Omer; Vikstrom, Karen L; Kasprowicz, Kimberly; Bhatta, Luna; Puskas, Ferenc; Kalifa, Jérôme; Jalife, José

2009-10-01

The development of atrial fibrillation (AF) after cardiac surgery is associated with adverse outcomes; however, the mechanism(s) that trigger and maintain AF in these patients are unknown. The purpose of this study was to test our hypothesis that postoperative AF is maintained by high-frequency sources in the left atrium (LA) resulting from ion channel and structural features that differ from the right atrium (RA). Forty-four patients with no previous history of AF who underwent cardiac surgery consented to LA and RA biopsies. Histologic sections evaluated fatty infiltration, fibrosis, and iron deposition; quantitative reverse transcription-polymerase chain reaction (RT-PCR) assessed ion channel expression. In a subset of 27 patients, LA and RA unipolar recording leads were also placed. In patients who developed AF, the dominant frequency (DF) for each lead was calculated using fast Fourier transform. DFs during AF were LA 6.26 +/- 0.8 Hz, RA 4.56 +/- 0.7 Hz (P <.01). RT-PCR revealed LA-to-RA differences in mRNA abundance for Kir2.3 (1.8:1) and Kir3.4 (2.3:1). While LA fibrosis was greater in patients developing AF compared with those remaining in normal sinus rhythm (10.8% +/- 11% vs. 3.8% +/- 3.5%; P = .03), the amount of LA fibrosis inversely correlated with the LA DF. This is the first demonstration of LA-to-RA frequency differences during postoperative AF, which are associated with LA-to-RA differences in mRNA levels for potassium channel proteins and LA fibrosis. These results strongly suggest that sources of AF after cardiac surgery are located in the LA and are stabilized by LA fibrosis.

Silencing Nicotiana attenuata LHY and ZTL alters circadian rhythms in flowers

PubMed Central

Yon, Felipe; Joo, Youngsung; Cortés Llorca, Lucas; Rothe, Eva; Baldwin, Ian T.; Kim, Sang-Gyu

2016-01-01

Summary The rhythmic opening/closing and volatile emissions of flowers is known to attract pollinators at specific times. That these rhythms are maintained under constant light or dark conditions suggests a circadian clock involvement. Although a forward and reverse genetic approach led to the identification of core circadian clock components in Arabidopsis thaliana, involvement of these clock components for floral rhythms remained untested likely due to weak diurnal rhythms in A. thaliana flowers.Here we addressed the role of these core clock components in the flowers of the wild tobacco Nicotiana attenuata, whose flowers open at night, emit benzyl acetone (BA) scents, and move vertically through a 140° arc.We first measured N. attenuata floral rhythms under constant light conditions. The results suggest that the circadian clock controls flower opening, BA emission, and pedicel movement, but not flower closing.We generated transgenic N. attenuata lines silenced in the homologous genes of Arabidopsis LATE ELONGATED HYPOCOTYL (LHY) and ZEITLUPE (ZTL), which are known as a core clock component. Silencing NaLHY and NaZTL strongly altered floral rhythms in different ways, indicating that conserved clock components in N. attenuata coordinate these floral rhythms. PMID:26439540

Relative Salience of Speech Rhythm and Speech Rate on Perceived Foreign Accent in a Second Language.

PubMed

Polyanskaya, Leona; Ordin, Mikhail; Busa, Maria Grazia

2017-09-01

We investigated the independent contribution of speech rate and speech rhythm to perceived foreign accent. To address this issue we used a resynthesis technique that allows neutralizing segmental and tonal idiosyncrasies between identical sentences produced by French learners of English at different proficiency levels and maintaining the idiosyncrasies pertaining to prosodic timing patterns. We created stimuli that (1) preserved the idiosyncrasies in speech rhythm while controlling for the differences in speech rate between the utterances; (2) preserved the idiosyncrasies in speech rate while controlling for the differences in speech rhythm between the utterances; and (3) preserved the idiosyncrasies both in speech rate and speech rhythm. All the stimuli were created in intoned (with imposed intonational contour) and flat (with monotonized, constant F0) conditions. The original and the resynthesized sentences were rated by native speakers of English for degree of foreign accent. We found that both speech rate and speech rhythm influence the degree of perceived foreign accent, but the effect of speech rhythm is larger than that of speech rate. We also found that intonation enhances the perception of fine differences in rhythmic patterns but reduces the perceptual salience of fine differences in speech rate.

Metabolic heat production, heat loss and the circadian rhythm of body temperature in the rat.

PubMed

Refinetti, Roberto

2003-05-01

Metabolic heat production (calculated from oxygen consumption), dry heat loss (measured in a calorimeter) and body temperature (measured by telemetry) were recorded simultaneously at 6 min intervals over five consecutive days in rats maintained in constant darkness. Robust circadian rhythmicity (confirmed by chi square periodogram analysis) was observed in all three variables. The rhythm of heat production was phase-advanced by about half an hour in relation to the body temperature rhythm, whereas the rhythm of heat loss was phase-delayed by about half an hour. The balance of heat production and heat loss exhibited a daily oscillation 180 deg out of phase with the oscillation in body temperature. Computations indicated that the amount of heat associated with the generation of the body temperature rhythm (1.6 kJ) corresponds to less than 1 % of the total daily energy budget (172 kJ) in this species. Because of the small magnitude of the fraction of heat balance associated with the body temperature rhythm, it is likely that the daily oscillation in heat balance has a very slow effect on body temperature, thus accounting for the 180 deg phase difference between the rhythms of heat balance and body temperature.

Environmental Disruption of Circadian Rhythm Predisposes Mice to Osteoarthritis-Like Changes in Knee Joint

PubMed Central

Voigt, Robin M; Ellman, Michael B; Summa, Keith C; Vitaterna, Martha Hotz; Keshavarizian, Ali; Turek, Fred W; Meng, Qing-Jun; Stein, Gary S.; van Wijnen, Andre J.; Chen, Di; Forsyth, Christopher B; Im, Hee-Jeong

2015-01-01

Circadian rhythm dysfunction is linked to many diseases, yet pathophysiological roles in articular cartilage homeostasis and degenerative joint disease including osteoarthritis (OA) remains to be investigated in vivo. Here, we tested whether environmental or genetic disruption of circadian homeostasis predisposes to OA-like pathological changes. Male mice were examined for circadian locomotor activity upon changes in the light:dark (LD) cycle or genetic disruption of circadian rhythms. Wild-type (WT) mice were maintained on a constant 12 hour:12 hour LD cycle (12:12 LD) or exposed to weekly 12 hour phase shifts. Alternatively, male circadian mutant mice (ClockΔ19 or Csnk1etau mutants) were compared with age-matched WT littermates that were maintained on a constant 12:12 LD cycle. Disruption of circadian rhythms promoted osteoarthritic changes by suppressing proteoglycan accumulation, upregulating matrix-degrading enzymes and downregulating anabolic mediators in the mouse knee joint. Mechanistically, these effects involved activation of the PKCδ-ERK-RUNX2/NFκB and β-catenin signaling pathways, stimulation of MMP-13 and ADAMTS-5, as well as suppression of the anabolic mediators SOX9 and TIMP-3 in articular chondrocytes of phase-shifted mice. Genetic disruption of circadian homeostasis does not predispose to OA-like pathological changes in joints. Our results, for the first time, provide compelling in vivo evidence that environmental disruption of circadian rhythms is a risk factor for the development of OA-like pathological changes in the mouse knee joint. PMID:25655021

Activity-rest stimulation protocol improves cardiac assistance in dynamic cardiomyoplasty.

PubMed

Rigatelli, Gianluca; Carraro, Ugo; Barbiero, Mario; Zanchetta, Mario; Dimopoulos, Konstantinos; Cobelli, Franco; Riccardi, Riccardo; Rigatelli, Giorgio

2002-03-01

No data have ever been published regarding cardiac assistance in demand dynamic cardiomyoplasty (DDCMP). We tested the efficacy of the Doppler flow wire in measuring beat-to-beat aortic flow velocity and evaluating cardiac assistance in demand cardiomyoplasty patients. The technique was tested in seven patients (M/F=6/1; age=57.1+/-6.2 years; atrial fibrillation/sinus rhythm=1/6; NYHA=1.4+/-0.5). Measurements were done using a 0.018inch peripheral Doppler flow wire advanced through a 5F arterial femoral sheath. Three 1-min periods with the stimulator off and three 1-min periods with clinical stimulation were recorded. We measured peak aortic flow velocity in all beats. Latissimus dorsi (LD) mechanogram was simultaneously recorded. Comparison between pre-operative and follow-up data showed significantly higher values of tetanic fusion frequency (TFF) and ejection fraction at follow-up, whereas mean NYHA class was significantly lower. Statistical analysis showed an increase in aortic flow velocity not only in assisted versus rest period, but also in assisted versus unassisted beats (8.42+/-6.98% and 7.55+/-3.07%). A linear correlation was found between the increase in flow velocity and LD wrap TFF (r(2)=0.53). In DDCMP, systolic assistance is significant and correlated to LD speed of contraction; demand stimulation protocol maintains muscle properties and increases muscle performance.

Dronedarone for the treatment of atrial fibrillation and atrial flutter: approval and efficacy.

PubMed

Wolbrette, Deborah; Gonzalez, Mario; Samii, Soraya; Banchs, Javier; Penny-Peterson, Erica; Naccarelli, Gerald

2010-08-09

Dronedarone, a new Class III antiarrhythmic agent, has now been approved by the US Food and Drug Administration for use in patients with atrial fibrillation or atrial flutter. Approval came in March 2009 due to the positive results of the ATHENA trial showing significant reductions in all-cause mortality and cardiovascular hospitalization with dronedarone use. A post hoc analysis of the ATHENA data also suggested a decrease in stroke risk with this agent. However, due to safety concerns in the heart failure population in the earlier ANDROMEDA trial, dronedarone is not recommended for patients with an ejection fraction <35% and recent decompensated heart failure. Dronedarone is an amiodarone analog with multichannel blocking electrophysiologic properties similar to those of amiodarone, but several structural differences. Dronedarone's lack of the iodine moiety reduces its potential for thyroid and pulmonary toxicity. Preliminary data from the DIONYSOS trial, and an indirect meta-analysis comparing amiodarone with dronedarone, showed amiodarone to be more effective in maintaining sinus rhythm, while dronedarone was associated with fewer adverse effects resulting in early termination of the drug. Dronedarone is the first antiarrhythmic drug for the treatment of atrial fibrillation and atrial flutter shown to reduce cardiovascular hospitalizations. In patients with structural heart disease who have an ejection fraction >35% and no recent decompensated heart failure, dronedarone should be considered earlier than amiodarone in the treatment algorithm.

History of surgery for atrial fibrillation.

PubMed

Edgerton, Zachary J; Edgerton, James R

2009-12-01

There is a rich history of surgery for atrial fibrillation. Initial procedures were aimed at controlling the ventricular response rate. Later procedures were directed at converting atrial fibrillation to normal sinus rhythm. These culminated in the Cox Maze III procedure. While highly effective, the complexity and morbidity of the cut and sew Maze III limited its adoption. Enabling technology has developed alternate energy sources designed to produce a transmural atrial scar without cutting and sewing. Termed the Maze IV, this lessened the morbidity of the procedure and widened the applicability. Further advances in minimal access techniques are now being developed to allow totally thorascopic placement of all the left atrial lesions on the full, beating heart, using alternate energy sources.

Calcitonin receptors are ancient modulators for rhythms of preferential temperature in insects and body temperature in mammals.

PubMed

Goda, Tadahiro; Doi, Masao; Umezaki, Yujiro; Murai, Iori; Shimatani, Hiroyuki; Chu, Michelle L; Nguyen, Victoria H; Okamura, Hitoshi; Hamada, Fumika N

2018-01-15

Daily body temperature rhythm (BTR) is essential for maintaining homeostasis. BTR is regulated separately from locomotor activity rhythms, but its molecular basis is largely unknown. While mammals internally regulate BTR, ectotherms, including Drosophila , exhibit temperature preference rhythm (TPR) behavior to regulate BTR. Here, we demonstrate that the diuretic hormone 31 receptor (DH31R) mediates TPR during the active phase in Drosophila DH31R is expressed in clock cells, and its ligand, DH31, acts on clock cells to regulate TPR during the active phase. Surprisingly, the mouse homolog of DH31R, calcitonin receptor (Calcr), is expressed in the suprachiasmatic nucleus (SCN) and mediates body temperature fluctuations during the active phase in mice. Importantly, DH31R and Calcr are not required for coordinating locomotor activity rhythms. Our results represent the first molecular evidence that BTR is regulated distinctly from locomotor activity rhythms and show that DH31R/Calcr is an ancient specific mediator of BTR during the active phase in organisms ranging from ectotherms to endotherms. © 2018 Goda et al.; Published by Cold Spring Harbor Laboratory Press.

Alveolar ridge and maxillary sinus augmentation using rhBMP-2: a systematic review.

PubMed

Freitas, Rubens Moreno de; Spin-Neto, Rubens; Marcantonio Junior, Elcio; Pereira, Luís Antônio Violin Dias; Wikesjö, Ulf M E; Susin, Cristiano

2015-01-01

The aim of this systematic review was to evaluate clinical and safety data for recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier when used for alveolar ridge/maxillary sinus augmentation in humans. Clinical studies/case series published 1980 through June 2012 using rhBMP-2/ACS were searched. Studies meeting the following criteria were considered eligible for inclusion: >10 subjects at baseline and maxillary sinus or alveolar ridge augmentation not concomitant with implant placement. Seven of 69 publications were eligible for review. rhBMP-2/ACS yielded clinically meaningful bone formation for maxillary sinus augmentation that would allow placement of regular dental implants without consistent differences between rhBMP-2 concentrations. Nevertheless, the statistical analysis showed that sinus augmentation following autogenous bone graft was significantly greater (mean bone height: 1.6 mm, 95% CI: 0.5-2.7 mm) than for rhBMP-2/ACS (rhBMP-2 at 1.5 mg/mL). In extraction sockets, rhBMP-2/ACS maintained alveolar ridge height while enhancing alveolar ridge width. Safety reports did not represent concerns for the proposed indications. rhBMP-2/ACS appears a promising alternative to autogenous bone grafts for alveolar ridge/maxillary sinus augmentation; dose and carrier optimization may expand its efficacy, use, and clinical application. © 2013 Wiley Periodicals, Inc.

The circatidal rhythm persists without the optic lobe in the mangrove cricket Apteronemobius asahinai.

PubMed

Takekata, Hiroki; Numata, Hideharu; Shiga, Sakiko

2014-02-01

Whether the circatidal rhythm is generated by a machinery common to the circadian clock is one of the important and interesting questions in chronobiology. The mangrove cricket Apteronemobius asahinai shows a circatidal rhythm generating active and inactive phases and a circadian rhythm modifying the circatidal rhythm by inhibiting activity during the subjective day simultaneously. In the previous study, RNA interference of the circadian clock gene period disrupted the circadian rhythm but not the circatidal rhythm, suggesting a difference in molecular mechanisms between the circatidal and circadian rhythms. In the present study, to compare the neural mechanisms of these 2 rhythms, we observed locomotor activity in the mangrove cricket after surgical removal of the optic lobe, which has been shown to be the locus of the circadian clock in other crickets. We also noted the pigment-dispersing factor immunoreactive neurons (PDF-IRNs) in the optic lobe, because PDF is a key output molecule in the circadian clock system in some insects. The results showed that the circadian modulation was disrupted after the removal of the optic lobes but that the circatidal rhythm was maintained with no remarkable changes in its free-running period. Even in crickets in which some PDF-immunoreactive somata remained after removal of the optic lobe, the circadian rhythm was completely disrupted. The remnants of PDF-IRNs were not correlated to the occurrence and free-running period of the circatidal rhythm. These results indicate that the principal circatidal clock is located in a region(s) different from the optic lobe, whereas the circadian clock is located in the optic lobe, as in other crickets, and PDF-IRNs are not important for circatidal rhythm. Therefore, it is suggested that the circatidal rhythm of A. asahinai is driven by a neural basis different from that driving the circadian rhythm.

Diadenosine Polyphosphates Suppress the Effects of Sympathetic Nerve Stimulation in Rabbit Heart Pacemaker.

PubMed

Abramochkin, D V; Pustovit, K B; Kuz'min, V S

2017-09-01

The modulatory influence of diadenosine tetraphosphate (Ap4A) and diadenosine pentaphosphate (Ap5A) on the effect of intramural autonomic nerve stimulation in isolated rabbit sinoatrial node were examined. Electrical activity of the sinoatrial node was recorded intracellularly. Against the background of blockade of adrenergic effects with propranolol (3×10 -6 M) or in preparations isolated 2 h after injection of reserpine (2 mg/kg), nerve stimulation induced short-term membrane hyperpolarization and diminished the sinus node firing rate. These phenomena were not affected by Ap4A or Ap5A (10 -5 M). Under the action of atropine (3×10 -6 M) that completely eliminated the cholinergic influences, nerve stimulation enhanced the sinus node firing rate by 17.30±3.45% from the initial rate. Both Ap4A and Ap5A moderated the stimulation-induced elevation of firing rate to 9.9±2.8 and 10.5±2.9%, respectively. The data suggest that diadenosine polyphosphates significantly modulate the sympathetic influences on the heart rhythm, but have no effect on the parasympathetic control over activity of sinoatrial node.

Postoperative administration of landiolol hydrochloride for patients with supraventricular arrhythmia: the efficacy of sustained intravenous infusion at a low dose.

PubMed

Wariishi, Seiichiro; Yamashita, Koichi; Nishimori, Hideaki; Fukutomi, Takashi; Yamamoto, Masaki; Radhakrishnan, Geethalakshmi; Sasaguri, Shiro

2009-11-01

The purpose of this study was to investigate the efficacy of landiolol hydrochloride, a short-acting beta(1) blocker, by initiating its administration at a low dose (5 microg kg(-1) min(-1)) in patients with postoperative supraventricular arrhythmia. The efficacy of landiolol was evaluated in 38 patients who, after developing postoperative atrial flutter or fibrillation, with sinus tachycardia and two patients who had a history of paroxysmal atrial fibrillation with frequent atrial extrasystole. The heart rate and blood pressure before and 2 h after the administration of landiolol were compared. A return to the sinus rhythm from supraventricular arrhythmia was noted in 89%. The heart rate was reduced from 137+/-26 bpm (before landiolol administration) to 93+/-18 bpm (2 h after the start of the medication, P<0.01). As an agent to correct an arrhythmic condition, landiolol successfully raised the systolic blood pressure from 108+/-24 mmHg (before medication) to 120+/-19 mmHg (2 h after the medication was started, P<0.05). Continuous intravenous infusion of landiolol at a low dose was found to be effective for postoperative supraventricular arrhythmia.

Resetting of circadian melatonin and cortisol rhythms in humans by ordinary room light

NASA Technical Reports Server (NTRS)

Boivin, D. B.; Czeisler, C. A.

1998-01-01

The present study was designed to investigate whether a weak photic stimulus can reset the endogenous circadian rhythms of plasma melatonin and plasma cortisol in human subjects. A stimulus consisting of three cycles of 5 h exposures to ordinary room light (approximately 180 lux), centered 1.5 h after the endogenous temperature nadir, significantly phase-advanced the plasma melatonin rhythm in eight healthy young men compared with the phase delays observed in eight control subjects who underwent the same protocol but were exposed to darkness (p < or = 0.003). After light-induced phase advances, the circadian rhythms of plasma melatonin and plasma cortisol maintained stable temporal relationships with the endogenous core body temperature cycle, consistent with the conclusion that exposure to ordinary indoor room light had shifted a master circadian pacemaker.

Modified carotid sinus massage using an ultrasonography for maximizing vagal tone: a crossover simulation study.

PubMed

Ha, Seung Min; Cho, Young Suk; Cho, Gyu Chong; Jo, Choong Hyun; Ryu, Ji Young

2015-07-01

The aim of this study was to ascertain if a modified carotid sinus massage (CSM) using ultrasonography is superior to the conventional CSM for vagal tone generation. This was a prospective, crossover, clinical trial including 30 subjects with sinus rhythm. Participants were paired, and they performed 2 types of CSM to each other. To perform the conventional technique, pressure was exerted at the point where the maximal impulse of the carotid pulse was palpated. In the modified technique, participants localized the point of maximal diameter just above the bifurcation of the common carotid artery using ultrasonography and applied pressure to that point. Mean differences between premaneuver and postmaneuver R-R intervals and heart rates were compared. The distance from the midline of the neck (x distance) to the angle of the mandible (y distance) was measured, and the mean distance between the 2 techniques was compared. The baseline mean premaneuver R-R interval and heart rate did not differ significantly between the 2 techniques. The postmaneuver R-R interval and heart rate as well as the mean R-R interval and heart rate differences were significantly greater in the modified CSM. The mean location determined using the modified CSM was located 0.8 cm lateral and 0.8 cm superior to the mean location of the conventional CSM. The modified CSM using ultrasonography might be more useful than the conventional CSM in reverting episodes of paroxysmal supraventricular tachycardia and may be a suitable alternative for treating the same in the emergency department. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

[Premature outflow tract ventricular contraction combined with complete bundle branch block: the characteristic electrocardiographic and ablation target potential features].

PubMed

Di, C Y; Wan, Z; Li, K; Ding, Y S; Lin, W H

2017-12-01

Objective: To explore the characteristics of electrocardiogram(ECG) and target potential features of premature ventricular contraction (PVC) in patients with complete left/right bundle branch block (CL/RBBB) and compare with those without CL/RBBB. Methods: A retrospective analysis was done in 8 outflow tract PVC patients with CL/RBBB, who successfully underwent radiofrequency ablation from August 2009 to June 2017. According to the bundle branch block chamber, patients were divided into the complete right bundle branch block (CRBBB) group ( n= 4) and the complete left bundle branch block (CLBBB) group ( n= 4). The control group were those who successfully underwent ablation at the same position as the above two groups but without CL/RBBB. The characteristics of ECG and target potential features were compared among groups. Results: One case in the CRBBB group was successfully ablated in the great cardiac vein with precordial R/S>1 transition at V(1) and one case in the CLBBB group was successfully ablated in the right coronary cusp with precordial R/S>1 transition at V(2), while other 6 cases were all with precordial R/S>1 transition at lead V(4). Precordial R/S>1 transition was not later than sinus rhythm (SR) in the CLBBB group. No statistical difference was found in the QRS complex duration between SR and PVC in the CL/RBBB patients [(134.38±23.80)ms vs (156.75±25.93)ms, P> 0.05], while statistical difference was shown in the control group [(92.63±5.76)ms vs (140.25±15.97)ms, P< 0.05]. Conclusion: Bundle branch block can lead to misjudgment of PVC origin with CL/RBBB during sinus rhythm, thus the origin chamber of the PVC should be determined according to the mapping and ablation result.

Mortal hyperkalemia disturbances in rats are NO-system related. The life saving effect of pentadecapeptide BPC 157.

PubMed

Barisic, Ivan; Balenovic, Diana; Klicek, Robert; Radic, Bozo; Nikitovic, Bojana; Drmic, Domagoj; Udovicic, Mario; Strinic, Dean; Bardak, Darija; Berkopic, Lidija; Djuzel, Viktor; Sever, Marko; Cvjetko, Ivan; Romic, Zeljko; Sindic, Aleksandra; Bencic, Martina Lovric; Seiwerth, Sven; Sikiric, Predrag

2013-02-10

We demonstrate the full counteracting ability of stable gastric pentadecapeptide BPC 157 against KCl-overdose (intraperitoneal (i), intragastric (ii), in vitro (iii)), NO-system related. (i) We demonstrated potential (/kg) of: BPC 157 (10ng, 10μg ip, complete counteraction), l-arginine (100mg ip, attenuation) vs. L-NAME (5mg ip, deadly aggravation), given alone and/or combined, before or after intraperitoneal KCl-solution application (9mEq/kg). Therapy was confronted with promptly unrelenting hyperkalemia (>12mmol/L), arrhythmias (and muscular weakness, hypertension, low pressure in lower esophageal and pyloric sphincter) with an ultimate and a regularly inevitable lethal outcome within 30min. Previously, we established BPC 157-NO-system interaction; now, a huge life-saving potential. Given 30min before KCl, all BPC 157 regimens regained sinus rhythm, had less prolongation of QRS, and had no asystolic pause. BPC 157 therapy, given 10min after KCl-application, starts the rescue within 5-10min, completely restoring normal sinus rhythm at 1h. Likewise, other hyperkalemia-disturbances (muscular weakness, hypertension, low sphincteric pressure) were also counteracted. Accordingly with NO-system relation, deadly aggravation by L-NAME: l-arginine brings the values to the control levels while BPC 157 always completely nullified lesions, markedly below those of controls. Combined with l-arginine, BPC 157 exhibited no additive effect. (ii) Intragastric KCl-solution application (27mEq/kg) - (hyperkalemia 7mmol/L): severe stomach mucosal lesions, sphincter failure and peaked T waves were fully counteracted by intragastric BPC 157 (10ng, 10μg) application, given 30min before or 10min after KCl. (iii). In HEK293 cells, hyperkalemic conditions (18.6mM potassium concentrations), BPC 157 directly affects potassium conductance, counteracting the effect on membrane potential and depolarizations caused by hyperkalemic conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparison of Left Atrial Voltage between Sinus Rhythm and Atrial Fibrillation in Association with Electrogram Waveform.

PubMed

Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Sunaga, Akihiro; Tsujimura, Takuya; Matsuda, Yasuhiro; Ohashi, Takuya; Uematsu, Masaaki

2017-05-01

The efficacy of low-voltage-guided ablation in addition to pulmonary vein (PV) isolation for atrial fibrillation (AF) has been reported with voltage mapping being performed during sinus rhythm (SR) or AF. The study aimed to compare the left atrial voltage between SR and AF in association with the electrogram waveform. This prospective observational study included 30 consecutive patients with persistent AF. After completion of PV isolation, electrogram points were taken during both SR and AF at the identical locations evenly throughout the left atrium. Electrograms were divided into two types: normal (sharp electrogram with ≤3 peaks or duration <50 ms) and fractionated (>3 peaks and duration ≥50 ms). During SR, 14 (47%) patients had low-voltage (0.5 mV) substrate with an area of 6.8 ± 4.5 cm 2 . In a total of 1,063 point pairs, 135 (13%) demonstrated a fractionated electrogram during SR and 483 (45%) during AF. The locations with fractionated electrograms during AF more frequently showed fractionation during SR compared to those with normal electrograms during AF (23% vs 5%, P < 0.0001), and had lower amplitude during SR (1.47 ± 1.29 mV vs 2.03 ± 1.19 mV, P < 0.0001). Electrogram amplitude was higher during SR than that during AF (1.77 ± 1.27 mV vs 0.96 ± 0.77 mV, P < 0.0001) with a weak correlation (r = 0.56, P < 0.0001). Subgroup analyses revealed that the correlation was relatively strong (r = 0.73, P < 0.0001) among the electrogram amplitudes with normal waveform during SR and AF. Significant differences in electrogram voltage and fractionation degree may exist between SR and AF at the same locations in patients with persistent AF. © 2017 Wiley Periodicals, Inc.

Left atrial function measured by cardiac magnetic resonance imaging in patients with heart failure: clinical associations and prognostic value.

PubMed

Pellicori, Pierpaolo; Zhang, Jufen; Lukaschuk, Elena; Joseph, Anil C; Bourantas, Christos V; Loh, Huan; Bragadeesh, Thanjavur; Clark, Andrew L; Cleland, John G F

2015-03-21

Left atrial (LA) volume is an important marker of cardiac dysfunction and cardiovascular outcome in heart failure (HF), but LA function is rarely measured. Left atrial emptying function (LAEF), its clinical associations and prognostic value was studied in outpatients referred with suspected HF who were in sinus rhythm and had cardiac magnetic resonance imaging (CMRI). Heart failure was defined as relevant symptoms and signs with either a left ventricular ejection fraction (LVEF) <50% or amino-terminal pro-B-type natriuretic peptide (NTproBNP) >400 pg/mL (or >125 pg/mL if taking loop diuretics). Of 982 patients, 664 fulfilled the HF criteria and were in sinus rhythm. The median (interquartile range, IQR) LAEF was 42 (31-51)% and 55 (48-61)% in patients with and without HF (P < 0.001). Patients with HF in the lowest quartile of LAEF (23%; IQR: 17-28%) had lower LV and right ventricular (RV) EF, and greater LV and RV mass and higher plasma NTproBNP than those in the highest quartile of LAEF (56%; IQR: 53-61%). Log[LAEF] and log[NTproBNP] were inversely correlated (r = -0.410, P < 0.001). During a median follow-up of 883 (IQR: 469-1626) days, 394 (59%) patients with HF died or were admitted with HF and 101 (15%) developed atrial fibrillation (AF). In a multivariable Cox model, increasing LAEF, but not LVEF, was independently associated with survival (HR for 10% change: 0.81 (95%CI: 0.73-0.90), P = <0.001). Increasing age and decreasing LAEF predicted incident AF. In patients with HF, LAEF predicts adverse outcome independently of other measures of cardiac dysfunction. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

[Thoracoscopic, epicardial ablation of atrial fibrillation using the COBRA Fusion system as the first part of hybrid ablation].

PubMed

Budera, P; Osmančík, P; Talavera, D; Fojt, R; Kraupnerová, A; Žďárská, J; Vaněk, T; Straka, Z

2017-01-01

Treatment of persistent and long-standing persistent atrial fibrillation is not successfully managed by methods of catheter ablation or pharmacotherapy. Hybrid ablation (i.e. combination of minimally invasive surgical ablation, followed by electrophysiological assessment and subsequent endocardial catheter ablation to complete the entire intended procedure) presents an ever more used and very promising treatment method. Patients underwent thoracoscopic ablation of pulmonary veins and posterior wall of the left atrium (the box-lesion) with use of the COBRA Fusion catheter; thoracoscopic occlusion of the left atrial appendage using the AtriClip system was also done in later patients. After 23 months, electrophysiological assessment and catheter ablation followed. In this article we summarize a strategy of the surgical part of the hybrid procedure performed in our centre. We describe the surgery itself (including possible periprocedural complications) and we also present our short-term results, especially with respect to subsequent electrophysiological findings. Data of the first 51 patients were analyzed. The first 25 patients underwent unilateral ablation; the mean time of surgery was 102 min. Subsequent 26 patients underwent the bilateral procedure with the mean surgery time of 160 min. Serious complications included 1 stroke, 1 phrenic nerve palsy and 2 surgical re-explorations for bleeding. After 1 month, 65% of patients showed sinus rhythm. The box-lesion was found complete during electrophysiological assessment in 38% of patients and after catheter ablation, 96% of patients were discharged in sinus rhythm. The surgical part of the hybrid procedure with use of the minimally invasive approach and the COBRA Fusion catheter is a well-feasible method with a low number of periprocedural complications. For electrophysiologists, it provides a very good basis for successful completion of the hybrid ablation.Key words: atrial fibrillation hybrid ablation - thoracoscopy catheter ablation electrophysiology assessment.

Immediate Clinical and Echocardiographic Outcome of Percutaneous Transvenous Mitral Commissurotomy for Patients of Mitral Stenosis with Atrial Fibrillation.

PubMed

Rahman, M T; Rahman, M M; Islam, M M; Khan, M R; Haque, S A; Chowdhury, A W; Majumder, A S; Rahman, A; Islam, Q I

2015-07-01

Rheumatic fever and rheumatic heart disease continue to be the major health problem in all developing countries including Bangladesh. Rheumatic mitral stenosis is a very common problem in our population having an incidence of 54 percent among rheumatic heart disease with a female preponderance of 2:1. Percutaneous balloon mitral commissurotomy is appealing because the mechanism of valve dilation closely parallels the mechanism of surgical mitral commissurotomy. The technique of balloon mitral commissurotomy has evolved rapidly, with improvements in balloons, guide wires, and the application of double-balloon techniques. There is controversy that whether the presence of AF has a direct negative effect on the immediate or long-term outcome after PTMC in mitral stenosis patients. The purpose of this study was to see the effect of atrial fibrillation (AF) on the immediate clinical and echocardiographic outcome of patients undergoing Percutaneous Transvenous Mitral Commissurotomy (PTMC). The immediate procedural and in-hospital clinical outcome after PTMC of 264 patients with AF were prospectively collected and compared with those of 288 patients in normal sinus rhythm (NSR) with mitral stenosis admitted in National Institute of Cardiovascular Diseases, Dhaka and Al-Helal Heart Institute, Mirpur, Dhaka, Bangladesh. Patients with AF were older than patients with normal sinus rhythm (53 ± 11 vs. 33 ± 12 years; p<0.0001) and presented more frequently with New York Heart Association (NYHA) class III-IV (78.3% vs. 58.5%; p<0.0001), echocardiographic score >8 (38.9% vs. 22.7%; p<0.0001), calcified valves under fluoroscopy (22.2% vs.12.4%, p<0.0001) and with history of previous surgical commissurotomy (21.7% vs. 10.5%; p<0.0001). In patients with AF, PTMC resulted in worse outcomes, as reflected in a smaller post-PTMC mitral valve area (1.6±0.4 vs. 2.1 ± 0.8 cm²; p<0.0001). Patients with atrial fibrillation have a worse immediate clinical and echocardiographic outcome after PTMC.

Quality of Anticoagulation Control in Preventing Adverse Events in Heart Failure Patients in Sinus Rhythm: A Warfarin Aspirin Reduced Cardiac Ejection Fraction Trial (WARCEF) Substudy

PubMed Central

Homma, Shunichi; Thompson, John L.P.; Qian, Min; Ye, Siqin; Di Tullio, Marco R.; Lip, Gregory Y.H.; Mann, Douglas L.; Sacco, Ralph L.; Levin, Bruce; Pullicino, Patrick M.; Freudenberger, Ronald S.; Teerlink, John R.; Graham, Susan; Mohr, J.P.; Labovitz, Arthur J.; Buchsbaum, Richard; Estol, Conrado J.; Lok, Dirk J.; Ponikowski, Piotr; Anker, Stefan D.

2015-01-01

Background The aim of this study is to examine the relationship between time in therapeutic range (TTR) and clinical outcomes in heart failure (HF) patients in sinus rhythm (SR) treated with warfarin. Methods and Results We used data from the Warfarin vs. Aspirin in Reduced Cardiac Ejection Fraction Trial (WARCEF) to assess the relationship of TTR with the WARCEF primary outcome (ischemic stroke, intracerebral hemorrhage, or death); with death alone; ischemic stroke alone; major hemorrhage alone; and net clinical benefit (primary outcome and major hemorrhage combined). Multivariable Cox models were used to examine how the event risk changed with TTR and to compare the high TTR, low TTR, and aspirin patients, with TTR being treated as a time-dependent covariate. 2,217 patients were included in the analyses, among whom 1,067 were randomized to warfarin and 1,150 were randomized to aspirin. The median (IQR) follow-up duration was 3.6 (2.0–5.0) years. Mean (±SD) age was 61±11.3 years, with 80% being men. The mean (±SD) TTR was 57% (±28.5%). Increasing TTR was significantly associated with reduction in primary outcome (adjusted p<0.001), death alone (adjusted p=0.001), and improved net clinical benefit (adjusted p<0.001). A similar trend was observed for the other two outcomes but significance was not reached (adjusted p=0.082 for ischemic stroke, adjusted p=0.109 for major hemorrhage). Conclusions In HF patients in SR, increasing TTR is associated with better outcome and improved net clinical benefit. Patients in whom good quality anticoagulation can be achieved may benefit from the use of anticoagulants. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00041938. PMID:25850425

Bleeding Risk and Antithrombotic Strategy in Patients with Sinus Rhythm Heart Failure with Reduced Ejection Fraction Treated with Warfarin or Aspirin

PubMed Central

Ye, Siqin; Cheng, Bin; Lip, Gregory Y. H.; Buchsbaum, Richard; Sacco, Ralph L.; Levin, Bruce; Di Tullio, Marco R.; Qian, Min; Mann, Douglas L.; Pullicino, Patrick M.; Freudenberger, Ronald S.; Teerlink, John R.; Mohr, J.P.; Graham, Susan; Labovitz, Arthur J.; Estol, Conrado J.; Lok, Dirk J.; Ponikowski, Piotr; Anker, Stefan D.; Thompson, John L.P.; Homma, Shunichi

2015-01-01

We sought to assess the performance of existing bleeding risk scores, such as HAS-BLED or OBRI, in patients with heart failure with reduced ejection fraction (HFrEF) in sinus rhythm (SR) treated with warfarin or aspirin. We calculated HAS-BLED and OBRI risk scores for 2,305 patients with HFrEF in SR enrolled in the Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction (WARCEF) trial. Proportional hazards models were used to test whether each score predicted major bleeding, and comparison of different risk scores was performed using Harell’s c-statistic and net-reclassification improvement (NRI) index. For the warfarin arm, both scores predicted bleeding risk, with OBRI having significantly higher c-statistic (0.72 vs 0.61; p=0.03) compared to HAS-BLED, though the NRI for comparing OBRI to HAS-BLED was not significant (0.32, 95% CI - 0.18-0.37). Performance of the OBRI and HAS-BLED risk scores were similar for the aspirin arm. For participants with OBRI score of 0 to 1, warfarin compared with aspirin reduced ischemic stroke (HR 0.51, 95% CI 0.26-0.98, p=0.042) without significantly increasing major bleeding (HR 1.24, 95% CI 0.66-2.30, p=0.51). For those with OBRI score of ≥2, there was a trend for reduced ischemic stroke with warfarin compared to aspirin (HR 0.56, 95% CI 0.27-1.15, p=0.12), but major bleeding was increased (HR 4.04, 95% CI 1.99-8.22, p<0.001). In conclusion, existing bleeding risk scores can identify bleeding risk in HFrEF patients in SR, and could be tested for potentially identifying patients with a favorable risk / benefit profile for antithrombotic therapy with warfarin. PMID:26189039

Accuracy of a Wrist-Worn Wearable Device for Monitoring Heart Rates in Hospital Inpatients: A Prospective Observational Study.

PubMed

Kroll, Ryan R; Boyd, J Gordon; Maslove, David M

2016-09-20

As the sensing capabilities of wearable devices improve, there is increasing interest in their application in medical settings. Capabilities such as heart rate monitoring may be useful in hospitalized patients as a means of enhancing routine monitoring or as part of an early warning system to detect clinical deterioration. To evaluate the accuracy of heart rate monitoring by a personal fitness tracker (PFT) among hospital inpatients. We conducted a prospective observational study of 50 stable patients in the intensive care unit who each completed 24 hours of heart rate monitoring using a wrist-worn PFT. Accuracy of heart rate recordings was compared with gold standard measurements derived from continuous electrocardiographic (cECG) monitoring. The accuracy of heart rates measured by pulse oximetry (Spo2.R) was also measured as a positive control. On a per-patient basis, PFT-derived heart rate values were slightly lower than those derived from cECG monitoring (average bias of -1.14 beats per minute [bpm], with limits of agreement of 24 bpm). By comparison, Spo2.R recordings produced more accurate values (average bias of +0.15 bpm, limits of agreement of 13 bpm, P<.001 as compared with PFT). Personal fitness tracker device performance was significantly better in patients in sinus rhythm than in those who were not (average bias -0.99 bpm vs -5.02 bpm, P=.02). Personal fitness tracker-derived heart rates were slightly lower than those derived from cECG monitoring in real-world testing and not as accurate as Spo2.R-derived heart rates. Performance was worse among patients who were not in sinus rhythm. Further clinical evaluation is indicated to see if PFTs can augment early warning systems in hospitals. ClinicalTrials.gov NCT02527408; https://clinicaltrials.gov/ct2/show/NCT02527408 (Archived by WebCite at  http://www.webcitation.org/6kOFez3on).

A randomized controlled trial of efficacy and ST change following use of the Welch-Allyn MRL PIC biphasic waveform versus damped sine monophasic waveform for external DC cardioversion.

PubMed

Ambler, Jonathan J S; Deakin, Charles D

2006-11-01

Biphasic waveforms have similar or greater efficacy at cardioverting atrial and ventricular arrhythmias at lower energy levels than monophasic waveforms, and cause less ST depression following defibrillation of ventricular fibrillation. No studies have investigated this effect on ST change with atrial arrhythmias. We studied the efficacy of the Welch Allyn-MRL PIC biphasic defibrillator. One hundred and thirty-nine patients undergoing elective DC cardioversion for atrial arrhythmias were randomised to cardioversion by monophasic (Hewlett Packard Codemaster XL; 100, 200, 300, 360 and 360J) or biphasic (Welch Allyn-MRL PIC; 70, 100, 150, 200 and 300J) defibrillator. We analysed success of cardioversion after 0 and 30min, cumulative energy, number of shocks and energy at successful cardioversion. The ST change in the recorded electrocardiogram was measured at 15s after all shocks using electronic callipers. Immediately after cardioversion 59/68 (86.8%) of the monophasic group versus 56/60 (93.3%) of the biphasic group were in sinus rhythm. Of the monophasic group, 55/67 (82.1%) remained in sinus rhythm at 30min versus 53/58 (91.4%) of the biphasic group. These differences were not significant at 0min (P=0.35) or 30min (P=0.21). The biphasic group required significantly fewer shocks (P=0.006), less cumulative energy (P<0.0001) and required lower total energy for successful cardioversion (P<0.0001). Of the 102 patients with electrocardiogram recordings suitable for analysis, ST segment change was greater in the monophasic group (P=0.037). The Welch Allyn-MRL biphasic waveform for DC cardioversion results in fewer shocks, with less cumulative energy delivered and less post shock ST change than with a Hewlett Packard Codemaster XL damped sine wave monophasic waveform.

Functional Tricuspid Regurgitation Caused by Chronic Atrial Fibrillation: A Real-Time 3-Dimensional Transesophageal Echocardiography Study.

PubMed

Utsunomiya, Hiroto; Itabashi, Yuji; Mihara, Hirotsugu; Berdejo, Javier; Kobayashi, Sayuki; Siegel, Robert J; Shiota, Takahiro

2017-01-01

Functional tricuspid regurgitation (TR) with a structurally normal tricuspid valve (TV) may occur secondary to chronic atrial fibrillation (AF). However, the clinical and echocardiographic differences according to functional TR subtypes are unclear. Therefore, characterization of functional TR because of chronic AF (AF-TR) remains undetermined. To investigate the prevalence of AF-TR, 437 patients with moderate to severe TR underwent 3-dimensional (3D) transesophageal echocardiography. TR severity was determined by the averaged vena contracta width on apical and parasternal inflow views. The prevalence of AF-TR was 9.2%, whereas that of functional TR because of left-sided heart disease was 45.3%. Clinical features of AF-TR included advanced age, female sex, greater right atrial than left atrial enlargement and lower systolic pulmonary artery pressure compared with left-sided heart disease-TR with sinus rhythm (all P<0.05). In 3D TV assessment, patients with AF-TR had a larger TV annular area with weaker annular contraction (both P<0.001) but a smaller tethering angle (P<0.001) despite a similar leaflet coaptation status compared with patients with left-sided heart disease-TR with sinus rhythm. On multivariable analysis, only the TV annular area in midsystole (coefficient, 0.059; 95% confidence interval, 0.041-0.078 per 100 mm 2 ; P<0.001) was associated with TR severity in AF-TR. The annular area was more closely correlated with the right atrial volume than right ventricular end-systolic volume in AF-TR (P<0.001). AF-TR is not rare and is associated with advanced age and right atrial enlargement. TV deformations and their association with right heart remodeling differ between AF-TR and left-sided heart disease-TR. Our results suggest that in patients with TR secondary to AF, TV annuloplasty should be effective because this entity has annular dilatation without leaflet deformation. © 2017 American Heart Association, Inc.

Diastolic Function in Normal Sinus Rhythm vs. Chronic Atrial Fibrillation: Comparison by Fractionation of E-wave Deceleration Time into Stiffness and Relaxation Components.

PubMed

Mossahebi, Sina; Kovács, Sándor J

2014-01-01

Although the electrophysiologic derangement responsible for atrial fibrillation (AF) has been elucidated, how AF remodels the ventricular chamber and affects diastolic function (DF) has not been fully characterized. The previously validated Parametrized Diastolic Filling (PDF) formalism models suction-initiated filling kinematically and generates error-minimized fits to E-wave contours using unique load (x o ), relaxation (c), and stiffness (k) parameters. It predicts that E-wave deceleration time (DT) is a function of both stiffness and relaxation. Ascribing DT s to stiffness and DTr to relaxation such that DT=DT s +DT r is legitimate because of causality and their predicted and observed high correlation (r=0.82 and r=0.94) with simultaneous (diastatic) chamber stiffness (dP/dV) and isovolumic relaxation (tau), respectively. We analyzed simultaneous echocardiography-cardiac catheterization data and compared 16 age matched, chronic AF subjects to 16, normal sinus rhythm (NSR) subjects (650 beats). All subjects had diastatic intervals. Conventional DF parameters (DT, AT, E peak , E dur , E-VTI, E/E') and E-wave derived PDF parameters (c, k, DT s , DT r ) were compared. Total DT and DT s , DT r in AF were shorter than in NSR (p<0.005), chamber stiffness, (k) in AF was higher than in NSR (p<0.001). For NSR, 75% of DT was due to stiffness and 25% was due to relaxation whereas for AF 81% of DT was due to stiffness and 19% was due to relaxation (p<0.005). We conclude that compared to NSR, increased chamber stiffness is one measurable consequence of chamber remodeling in chronic, rate controlled AF. A larger fraction of E-wave DT in AF is due to stiffness compared to NSR. By trending individual subjects, this method can elucidate and characterize the beneficial or adverse long-term effects on chamber remodeling due to alternative therapies in terms of chamber stiffness and relaxation.

Increased expression of mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase type 2 in human atria during atrial fibrillation.

PubMed

De-An, Pei; Li, Li; Zhi-Yun, Xu; Jin-Yu, Huang; Zheng-Ming, Xu; Min, Wang; Qiang, Yao; Shi-Eng, Huang

2010-01-01

Atrialfibrillation (AF) is associated with the activation of the renin-angiotensin-aldosterone system in the atria. It is not clear whether the expression of a mineralocorticoid receptor (MR), or 11beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2), conferring aldosterone specificity to the MR, in patients with AF is altered. Patients with AF may be associated with increased expression of MR and 11betaHSD2 in the atria. Atrial tissue samples of 25 patients with rheumatic heart valve disease undergoing a valve replacement operation were examined. A total of 13 patients had chronic persistent AF (>6 mo) and 12 patients had no history of AF. The MR and 11betaHSD2 expression were analyzed at the mRNA and protein level. The localization of MR and 11betaHSD2 in atrial tissue was performed using specific immunohistochemistry staining. The results of real-time quantitative polymerase chain reaction (PCR) showed that AF groups, in comparison with sinus rhythm, had a higher mRNA expression level of MR or 11betaHSD2 (all P < 0.01). Both the MR and 11betaHSD2 protein expression level in atrial tissue were also significantly increased in patients with AF compared with patients with sinus rhythm (P < 0.05 or P < 0.01). The immunohistochemical staining of MR or 11betaHSD2 demonstrated that MR and 11betaHSD2 predominately located in the cytoplasm of myocardial cells in the atrium and the intensity and density of immunostaining appeared to be increased in the atria of patients with AF compared to those without AF. Increasing expression of MR and 11betaHSD2 in the atria during AF is one of the molecular mechanisms for development of atrial interstitial fibrosis in patients with AF. These findings may have an important impact on the treatment of AF with aldosterone antagonists. Copyright 2010 Wiley Periodicals, Inc.

Increased expression of NF-AT3 and NF-AT4 in the atria correlates with procollagen I carboxyl terminal peptide and TGF-β1 levels in serum of patients with atrial fibrillation.

PubMed

Zhao, Fei; Zhang, ShiJiang; Chen, YiJiang; Gu, WeiDong; Ni, BuQing; Shao, YongFeng; Wu, YanHu; Qin, JianWei

2014-11-25

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. Unfortunately, the precise mechanisms and sensitive serum biomarkers of atrial remodeling in AF remain unclear. The aim of this study was to determine whether the expression of the transcription factors NF-AT3 and NF-AT4 correlate with atrial structural remodeling of atrial fibrillation and serum markers for collagen I and III synthesis. Right and left atrial specimens were obtained from 90 patients undergoing valve replacement surgery. The patients were divided into sinus rhythm (n = 30), paroxysmal atrial fibrillation (n = 30), and persistent atrial fibrillation (n = 30) groups. NF-AT3, NF-AT4, and collagen I and III mRNA and protein expression in atria were measured. We also tested the levels of the carboxyl-terminal peptide from pro-collagen I, the N-terminal type I procollagen propeptides, the N-terminal type III procollagen propeptides, and TGF-β1 in serum using an enzyme immunosorbent assay. NF-AT3 and NF-AT4 mRNA and protein expression were increased in the AF groups, especially in the left atrium. NF-AT3 and NF-AT4 expression in the right atrium was increased in the persistent atrial fibrillation group compared the sinus rhythm group with similar valvular disease. In patients with AF, the expression levels of nuclear NF-AT3 and NF-AT4 correlated with those of collagens I and III in the atria and with PICP and TGF-β1 in blood. These data support the hypothesis that nuclear NF-AT3 and NF-AT4 participates in atrial structural remodeling, and that PICP and TGF-β1 levels may be sensitive serum biomarkers to estimate atrial structural remodeling with atrial fibrillation.

Impact of heart rate in atrial fibrillation versus sinus rhythm on mortality in octogenarian patients with acute coronary syndrome.

PubMed

Li, Shijun; Barywani, Salim; Fu, Michael

2017-01-01

Association of heart rate (HR) with mortality in patients with acute coronary syndrome (ACS) and aged ≥ 80 years are underrepresented in clinical trials. We therefore aimed to investigate the association of HR in atrial fibrillation (AF) versus sinus rhythm (SR) with all-cause mortality in octogenarian patients with ACS. A total of 336 patients with ACS patients and aged ≥ 80 years were enrolled into the current study. The end point of interest was death from any cause. Association of HR in AF versus SR with mortality was analyzed by Kaplan-Meier curve following log-rank test and multivariable Cox regression analysis. In total, 63 (87.5%) of patients with AF were dead and 147 (59.8%) of patients with SR were dead during the follow-up period. The best cut-off was 80 bpm, with a sensitivity of 62% and specificity of 66%. HR ≤ 80 bpm in SR but not in AF was associated with better outcome as compared with HR > 80 bpm (Chi-Square = 26.55, Log rank P < 0.001). In SR subgroup, the hazard ratios of HR ≤ 80 bpm were 0.51(95% CI 0.37-0.70, P < 0.001) adjusted for age, 0.46 (95%CI 0.33-0.63, P < 0.001) adjusted for gender, 0.62 (95%CI 0.42- 0.93, P = 0.020) adjusted for multivariables respectively. In AF subgroup, the hazard ratios of HR ≤ 80 bpm were 0.83(95% CI 0.49-1.38, P = 0.464) adjusted for age, 0.96 (95%CI 0.59-1.58, P = 0.882) adjusted for gender, 0.72(95% CI 0.41-1.26, P = 0.249) adjusted for multivariables respectively. The current study demonstrates that heart rate is an independent prognostic predictor for all-cause mortality, and HR ≤ 80 bpm is associated with improved outcome in SR but not in AF in octogenarian patients with ACS.

A Prospective Study of Ripple Mapping the Post-Infarct Ventricular Scar to Guide Substrate Ablation for Ventricular Tachycardia.

PubMed

Luther, Vishal; Linton, Nick W F; Jamil-Copley, Shahnaz; Koa-Wing, Michael; Lim, Phang Boon; Qureshi, Norman; Ng, Fu Siong; Hayat, Sajad; Whinnett, Zachary; Davies, D Wyn; Peters, Nicholas S; Kanagaratnam, Prapa

2016-06-01

Post-infarct ventricular tachycardia is associated with channels of surviving myocardium within scar characterized by fractionated and low-amplitude signals usually occurring late during sinus rhythm. Conventional automated algorithms for 3-dimensional electro-anatomic mapping cannot differentiate the delayed local signal of conduction within the scar from the initial far-field signal generated by surrounding healthy tissue. Ripple mapping displays every deflection of an electrogram, thereby providing fully informative activation sequences. We prospectively used CARTO-based ripple maps to identify conducting channels as a target for ablation. High-density bipolar left ventricular endocardial electrograms were collected using CARTO3v4 in sinus rhythm or ventricular pacing and reviewed for ripple mapping conducting channel identification. Fifteen consecutive patients (median age 68 years, left ventricular ejection fraction 30%) were studied (6 month preprocedural implantable cardioverter defibrillator therapies: median 19 ATP events [Q1-Q3=4-93] and 1 shock [Q1-Q3=0-3]). Scar (<1.5 mV) occupied a median 29% of the total surface area (median 540 points collected within scar). A median of 2 ripple mapping conducting channels were seen within each scar (length 60 mm; initial component 0.44 mV; delayed component 0.20 mV; conduction 55 cm/s). Ablation was performed along all identified ripple mapping conducting channels (median 18 lesions) and any presumed interconnected late-activating sites (median 6 lesions; Q1-Q3=2-12). The diastolic isthmus in ventricular tachycardia was mapped in 3 patients and colocated within the ripple mapping conducting channels identified. Ventricular tachycardia was noninducible in 85% of patients post ablation, and 71% remain free of ventricular tachycardia recurrence at 6-month median follow-up. Ripple mapping can be used to identify conduction channels within scar to guide functional substrate ablation. © 2016 American Heart Association, Inc.

Revealing kinetics and state-dependent binding properties of IKur-targeting drugs that maximize atrial fibrillation selectivity

NASA Astrophysics Data System (ADS)

Ellinwood, Nicholas; Dobrev, Dobromir; Morotti, Stefano; Grandi, Eleonora

2017-09-01

The KV1.5 potassium channel, which underlies the ultra-rapid delayed-rectifier current (IKur) and is predominantly expressed in atria vs. ventricles, has emerged as a promising target to treat atrial fibrillation (AF). However, while numerous KV1.5-selective compounds have been screened, characterized, and tested in various animal models of AF, evidence of antiarrhythmic efficacy in humans is still lacking. Moreover, current guidelines for pre-clinical assessment of candidate drugs heavily rely on steady-state concentration-response curves or IC50 values, which can overlook adverse cardiotoxic effects. We sought to investigate the effects of kinetics and state-dependent binding of IKur-targeting drugs on atrial electrophysiology in silico and reveal the ideal properties of IKur blockers that maximize anti-AF efficacy and minimize pro-arrhythmic risk. To this aim, we developed a new Markov model of IKur that describes KV1.5 gating based on experimental voltage-clamp data in atrial myocytes from patient right-atrial samples in normal sinus rhythm. We extended the IKur formulation to account for state-specificity and kinetics of KV1.5-drug interactions and incorporated it into our human atrial cell model. We simulated 1- and 3-Hz pacing protocols in drug-free conditions and with a [drug] equal to the IC50 value. The effects of binding and unbinding kinetics were determined by examining permutations of the forward (kon) and reverse (koff) binding rates to the closed, open, and inactivated states of the KV1.5 channel. We identified a subset of ideal drugs exhibiting anti-AF electrophysiological parameter changes at fast pacing rates (effective refractory period prolongation), while having little effect on normal sinus rhythm (limited action potential prolongation). Our results highlight that accurately accounting for channel interactions with drugs, including kinetics and state-dependent binding, is critical for developing safer and more effective pharmacological anti-AF options.

Efficacy and safety in pharmacological cardioversion of recent-onset atrial fibrillation: a propensity score matching to compare amiodarone vs class IC antiarrhythmic drugs.

PubMed

Bonora, Antonio; Turcato, Gianni; Franchi, Elena; Taioli, Gabriele; Dilda, Alice; Zerman, Germana; Maccagnani, Antonio; Pistorelli, Claudio; Olivieri, Oliviero

2017-09-01

The acute management of recent-onset (<48 h) atrial fibrillation (AF) is still debated. Aim of our study was to compare efficacy and safety of intravenously administered class IC antidysrhythmic agents vs amiodarone in a propensity score matched series of patients acutely treated for AF in the emergency department. During a 3-year period, we retrospectively evaluated all episodes of recent-onset (<48 h) AF pharmacologically treated for sinus rhythm restoration in the emergency department. By means of a propensity score matching considering the main statistically different covariates, we selected two accurately matched treatment groups. We analysed the differences between amiodarone and class IC group in terms of efficacy and safety that is conversion to sinus rhythm rates within 12 and 48 h after starting treatment, time to conversion, and adverse drug effects. An overall number of 817 episodes of recent-onset AF were collected (amiodarone group = 406, class IC group = 411). After matching, we obtained 358 episodes equally divided (amiodarone group = 179 and class IC group = 179). Conversion rates within 12 h were 139 (53.1 %) in amiodarone group and 95 (72.6 %) in class IC group (p < 0.05). Median time for cardioversion was 420 min (331.6-508.3 CI 95 %) in amiodarone and 55 min (44.9-65.1 CI 95 %) in class IC group (p < 0.05). The incidence of adverse events in both groups was very low and equally distributed (p = ns). Intravenously administration of class IC agents, when compared with amiodarone, proved to be more rapid and effective, and equally safe in the acute management of recent-onset AF.

Environmental disruption of circadian rhythm predisposes mice to osteoarthritis-like changes in knee joint.

PubMed

Kc, Ranjan; Li, Xin; Voigt, Robin M; Ellman, Michael B; Summa, Keith C; Vitaterna, Martha Hotz; Keshavarizian, Ali; Turek, Fred W; Meng, Qing-Jun; Stein, Gary S; van Wijnen, Andre J; Chen, Di; Forsyth, Christopher B; Im, Hee-Jeong

2015-09-01

Circadian rhythm dysfunction is linked to many diseases, yet pathophysiological roles in articular cartilage homeostasis and degenerative joint disease including osteoarthritis (OA) remains to be investigated in vivo. Here, we tested whether environmental or genetic disruption of circadian homeostasis predisposes to OA-like pathological changes. Male mice were examined for circadian locomotor activity upon changes in the light:dark (LD) cycle or genetic disruption of circadian rhythms. Wild-type (WT) mice were maintained on a constant 12 h:12 h LD cycle (12:12 LD) or exposed to weekly 12 h phase shifts. Alternatively, male circadian mutant mice (Clock(Δ19) or Csnk1e(tau) mutants) were compared with age-matched WT littermates that were maintained on a constant 12:12 LD cycle. Disruption of circadian rhythms promoted osteoarthritic changes by suppressing proteoglycan accumulation, upregulating matrix-degrading enzymes and downregulating anabolic mediators in the mouse knee joint. Mechanistically, these effects involved activation of the PKCδ-ERK-RUNX2/NFκB and β-catenin signaling pathways, stimulation of MMP-13 and ADAMTS-5, as well as suppression of the anabolic mediators SOX9 and TIMP-3 in articular chondrocytes of phase-shifted mice. Genetic disruption of circadian homeostasis does not predispose to OA-like pathological changes in joints. Our results, for the first time, provide compelling in vivo evidence that environmental disruption of circadian rhythms is a risk factor for the development of OA-like pathological changes in the mouse knee joint. © 2015 Wiley Periodicals, Inc.

Silencing Nicotiana attenuata LHY and ZTL alters circadian rhythms in flowers.

PubMed

Yon, Felipe; Joo, Youngsung; Cortés Llorca, Lucas; Rothe, Eva; Baldwin, Ian T; Kim, Sang-Gyu

2016-02-01

The rhythmic opening/closing and volatile emissions of flowers are known to attract pollinators at specific times. That these rhythms are maintained under constant light or dark conditions suggests a circadian clock involvement. Although a forward and reverse genetic approach has led to the identification of core circadian clock components in Arabidopsis thaliana, the involvement of these clock components in floral rhythms has remained untested, probably because of the weak diurnal rhythms in A. thaliana flowers. Here, we addressed the role of these core clock components in the flowers of the wild tobacco Nicotiana attenuata, whose flowers open at night, emit benzyl acetone (BA) scents and move vertically through a 140° arc. We first measured N. attenuata floral rhythms under constant light conditions. The results suggest that the circadian clock controls flower opening, BA emission and pedicel movement, but not flower closing. We generated transgenic N. attenuata lines silenced in the homologous genes of Arabidopsis LATE ELONGATED HYPOCOTYL (LHY) and ZEITLUPE (ZTL), which are known to be core clock components. Silencing NaLHY and NaZTL strongly altered floral rhythms in different ways, indicating that conserved clock components in N. attenuata coordinate these floral rhythms. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Effects of restricted feeding schedules on circadian organization in squirrel monkeys

NASA Technical Reports Server (NTRS)

Boulos, Z.; Frim, D. M.; Dewey, L. K.; Moore-Ede, M. C.

1989-01-01

Free running circadian rhythms of motor activity, food-motivated lever-pressing, and either drinking (N = 7) or body temperature (N = 3) were recorded from 10 squirrel monkeys maintained in constant illumination with unlimited access to food. Food availability was then restricted to a single unsignaled 3-hour interval each day. The feeding schedule failed to entrain the activity rhythms of 8 monkeys, which continued to free-run. Drinking was almost completely synchronized by the schedule, while body temperature showed a feeding-induced rise superimposed on a free-running rhythm. Nonreinforced lever-pressing showed both a free-running component and a 24-hour component that anticipated the time of feeding. At the termination of the schedule, all recorded variables showed free-running rhythms, but in 3 animals the initial phase of the postschedule rhythms was advanced by several hours, suggesting relative coordination. Of the remaining 2 animals, one exhibited stable entrainment of all 3 recorded rhythms, while the other appeared to entrain temporarily to the feeding schedule. These results indicate that restricted feeding schedules are only a weak zeitgeber for the circadian pacemaker generating free-running rhythms in the squirrel monkey. Such schedules, however, may entrain a separate circadian system responsible for the timing of food-anticipatory changes in behavior and physiology.

A hybrid technique for sinus floor elevation in the severely resorbed posterior maxilla

PubMed Central

Jung, Ui-Won; Hong, Ji-Youn; Lee, Jung-Seok; Kim, Chang-Sung; Cho, Kyoo-Sung

2010-01-01

Purpose This study aimed to evaluate the effectiveness of the modified sinus floor elevation technique described hereafter as a "hybrid technique," in 11 patients with severely resorbed posterior maxillae. Methods Eleven patients who received 22 implants in the maxillary premolar and molar areas by the hybrid technique were enrolled in this study. A slot-shaped osteotomy for access was prepared on the lateral wall along the lower border of the sinus floor. The Schneiderian membrane was fully reflected through the lateral slot. Following drilling with the membrane protected by a periosteal elevator, the bone was grafted. All implants were placed simultaneously with sinus augmentation. The cumulative success rate was calculated and clinical parameters were recorded. Radiographic measurements were performed. Results All implants were well maintained at last follow up (cumulative success rate=100%). The mean residual bone height, augmented bone height, crown-to-implant ratio, and marginal bone loss were 4.1±1.64 mm, 8.76±1.77 mm, 1.21±0.33 mm, and 0.34±0.72 mm, respectively. Conclusions Simultaneous implant placement with sinus augmentation by hybrid technique showed successful clinical results over a 2-year observation period and may be a reliable modality for reconstruction of a severely resorbed posterior maxilla. PMID:20498764

Exercise-induced syncope in a 22-year-old man.

PubMed

Yeo, Colin; Tan, Vern Hsen; Wong, Kelvin Ck

2017-04-01

A 22-year-old man was referred to us for syncope during a game of Captain's ball. There was no prodrome. His friends did not notice any ictal movements. He was otherwise well prior to passing out. He was not taking any medications or supplements. He was not usually physically active, but was otherwise well with no significant medical history. This is his first episode of syncope. There was no history of cardiac arrest or seizures. There is no family history of premature sudden cardiac death.Physical examination was normal. ECG at rest demonstrated sinus rhythm with corrected QT interval of 400 ms. Echocardiography revealed a structurally normal heart. Holter monitoring was normal. Treadmill exercise stress test demonstrated the following rhythm on figure 1 during stage 4 Bruce protocol. Stress test was terminated in view of sustained arrhythmia as illustrated. He felt light-headed during the period, but otherwise felt that he could carry on with the exercise. ECG during recovery was unremarkable. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

A new therapeutic strategy for electrical cardioversion of atrial fibrillation.

PubMed

de Luca, I; Sorino, M; Del Salvatore, B; de Luca, L

2001-11-01

The conventional approach to cardioversion of atrial fibrillation includes a period of anticoagulation with oral anticoagulant therapy (OAT) extending from 3 weeks precardioversion to 4 weeks postcardioversion. The protocol of rapid anticoagulation (such as that of the ACUTE study) consists of a precardioversion transesophageal echocardiography (TEE) followed by OAT for 4 weeks. In the last few years low-molecular-weight heparins have established themselves as a safe and efficacious alternative to traditional antithrombotic therapies. The aim of this study was to demonstrate that the exclusion of thrombi by precardioversion TEE together with the exclusion of atrial stunning by a second TEE performed after 1 week, to date not suggested in the literature, could reduce to 7 days the period of pericardioversion anticoagulation. This therapy would be carried out using low-molecular-weight heparins with no need for biological monitoring and with the possibility of self-administration. We have studied 57 consecutive patients who had atrial fibrillation or flutter with a history of atrial fibrillation lasting > 48 hours. All patients received enoxaparin at a dosage of 100 IU antiXa/kg twice daily before undergoing multiplane TEE. Previous informed consent and ethical committee authorization had been obtained. Twenty-four hours following TEE, in the absence of thrombi and/or spontaneous moderate/severe echocontrast in the atrial chambers, the patients underwent electrical cardioversion and were discharged within 24 hours of sinus rhythm restoration. These patients were prescribed enoxaparin at the indicated dosage twice daily until TEE, performed in an outpatients setting 7 days following cardioversion. In the absence of thrombi and/or atrial and/or left atrial appendage stunning, OAT was terminated. Enoxaparin was associated with OAT for the following 3 weeks if any of the following signs of stunning were present: A wave inferior to the normal value for age at transmitral Doppler; a left atrial appendage emptying velocity < 40 cm/s; the appearance or increase in the severity of spontaneous echocontrast. For all patients, clinical and electrocardiographic follow-up was carried out at 1 month. In one patient TEE was not tolerated and one refused it. In 7 patients cardioversion was not performed: 4 because of the presence of thrombi, 1 because of moderate/severe spontaneous echocontrast and 2 owing to spontaneous cardioversion. Of the remaining 48 patients, cardioversion proved to be efficacious in 38, with sustained sinus rhythm at 1 week in 33 patients. One of these refused the second TEE and of the remaining 32 patients, 24 (75%) showed no signs of stunning at the second TEE and so anticoagulation was terminated. Thus, after 1 week, 75% (24/33) of patients in sinus rhythm could benefit from a shortened anticoagulation therapy which lasted for a mean of only 8.5 days. No patients showed signs of a thromboembolic accident at 1 and 2 months of follow-up. Most patients undergoing electrical cardioversion for atrial fibrillation could benefit from a shorter period of anticoagulation with low-molecular-weight heparins for 1 week if TEE precardioversion and 7 days postcardioversion excludes thrombi and atrial stunning. The management of patients with atrial fibrillation would be greatly simplified.

The influence of bone substitute materials on the bone volume after maxillary sinus augmentation: a microcomputerized tomography study.

PubMed

Kühl, Sebastian; Brochhausen, Christoph; Götz, Hermann; Filippi, Andreas; Payer, Michael; d'Hoedt, Bernd; Kreisler, Matthias

2013-03-01

This study aims to evaluate the effect of adding bone substitute materials (BSM) to particulated autogenous bone (PAB) on the volume fraction (Vf) of newly formed bone after maxillary sinus augmentation. Thirty healthy patients undergoing maxillary sinus augmentation were included. PAB (N = 10), mixtures of PAB and beta-tricalciumphosphate (PAB/β-TCP) (N = 10), as well as PAB and β-TCP and hydroxyapatite (PAB/HA/β-TCP) (N = 10) were randomly used for sinus augmentation. A sample of the graft material was maintained from each patient at time of maxillary sinus augmentation, and Vfs of the PAB and/or BSM in the samples were determined by means of microcomputerized tomography (μ-CT). Five months later, samples of the grafted areas were harvested during implantation using a trephine bur. μ-CT analysis of these samples was performed, and the Vf of bone and BSM were compared with the data obtained 5 months earlier from the original material. The mean Vf of the bone showed a statistically significant increase (p < 0.05) in all groups after a healing period of 5 months without statistically significant difference between the groups. With regard to the increase of bone volume, it is not relevant if PAB is used alone or combined with β-TCP or HA/β-TCP. The amount of PAB and associated donor site morbidity may be reduced by adding BSM for maxillary sinus augmentation.

Effect of spaceflight on the circadian rhythm, lifespan and gene expression of Drosophila melanogaster.

PubMed

Ma, Lingling; Ma, Jun; Xu, Kanyan

2015-01-01

Space travelers are reported to experience circadian rhythm disruption during spaceflight. However, how the space environment affects circadian rhythm is yet to be determined. The major focus of this study was to investigate the effect of spaceflight on the Drosophila circadian clock at both the behavioral and molecular level. We used China's Shenzhou-9 spaceship to carry Drosophila. After 13 days of spaceflight, behavior tests showed that the flies maintained normal locomotor activity rhythm and sleep pattern. The expression level and rhythm of major clock genes were also unaffected. However, expression profiling showed differentially regulated output genes of the circadian clock system between space flown and control flies, suggesting that spaceflight affected the circadian output pathway. We also investigated other physiological effects of spaceflight such as lipid metabolism and lifespan, and searched genes significantly affected by spaceflight using microarray analysis. These results provide new information on the effects of spaceflight on circadian rhythm, lipid metabolism and lifespan. Furthermore, we showed that studying the effect of spaceflight on gene expression using samples collected at different Zeitgeber time could obtain different results, suggesting the importance of appropriate sampling procedures in studies on the effects of spaceflight.

Effect of Spaceflight on the Circadian Rhythm, Lifespan and Gene Expression of Drosophila melanogaster

PubMed Central

Xu, Kanyan

2015-01-01

Space travelers are reported to experience circadian rhythm disruption during spaceflight. However, how the space environment affects circadian rhythm is yet to be determined. The major focus of this study was to investigate the effect of spaceflight on the Drosophila circadian clock at both the behavioral and molecular level. We used China’s Shenzhou-9 spaceship to carry Drosophila. After 13 days of spaceflight, behavior tests showed that the flies maintained normal locomotor activity rhythm and sleep pattern. The expression level and rhythm of major clock genes were also unaffected. However, expression profiling showed differentially regulated output genes of the circadian clock system between space flown and control flies, suggesting that spaceflight affected the circadian output pathway. We also investigated other physiological effects of spaceflight such as lipid metabolism and lifespan, and searched genes significantly affected by spaceflight using microarray analysis. These results provide new information on the effects of spaceflight on circadian rhythm, lipid metabolism and lifespan. Furthermore, we showed that studying the effect of spaceflight on gene expression using samples collected at different Zeitgeber time could obtain different results, suggesting the importance of appropriate sampling procedures in studies on the effects of spaceflight. PMID:25798821

Nonphotic entrainment of the human circadian pacemaker

NASA Technical Reports Server (NTRS)

Klerman, E. B.; Rimmer, D. W.; Dijk, D. J.; Kronauer, R. E.; Rizzo, J. F. 3rd; Czeisler, C. A.

1998-01-01

In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals "free run" even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

Propafenone

MedlinePlus

... arrhythmia (irregular heartbeat) and to maintain a normal heart rate. Propafenone is in a class of medications called antiarrhythmics. It works by acting on the heart muscle to improve the heart's rhythm.

A large left ventricular thrombus.

PubMed

Patanè, Salvatore; Marte, Filippo

2009-06-26

The discovery of a left ventricular mass obliges the clinician to perform a differential diagnosis including tumour or lipoma versus thrombus and its assessment presents important clinical implications. Dilated cardiomyopathy has been associated with left ventricular thrombosis which leads to substantial morbidity and mortality as a site for peripheral emboli. There are some studies on patients with dilated cardiomyopathy showing altered hemostasis and platelet behavior despite sinus rhythm. An increased incidence of thromboembolism is also well recognized in patients with left ventricular systolic dysfunction complicating history of myocardial infarction. Clinical dilemmas in treating left ventricular thrombus have been described too. We present a case of a large mobile left ventricular thrombus in a 71-year-old Italian man with dilated cardiomyopathy and history of myocardial infarction.

Second harmonic generation imaging of the collagen in myocardium for atrial fibrillation diagnosis

NASA Astrophysics Data System (ADS)

Tsai, Ming-Rung; Chiou, Yu-We; Sun, Chi-Kuang

2009-02-01

Myocardial fibrosis, a common sequela of cardiac hypertrophy, has been shown to be associated with arrhythmias in experimental models. Some research has indicated that myocardial fibrosis plays an important role in predisposing patients to atrial fibrillation. Second harmonic generation (SHG) is an optically nonlinear coherent process to image the collagen network. In this presentation, we observe the SHG images of the collagen matrix in atrial myocardium and we analyzed of collagen fibers arrangement by using Fourier-transform analysis. Moreover, comparing the SHG images of the collagen fibers in atrial myocardium between normal sinus rhythm (NSR) and atrial fibrillation (AF), our result indicated that it is possible to realize the relation between myocardial fibrosis and AF.

Endurance Sport Activity and Risk of Atrial Fibrillation – Epidemiology, Proposed Mechanisms and Management

PubMed Central

Vicedomini, Gabriele; Pappone, Carlo

2014-01-01

There is evidence for a higher prevalence of atrial fibrillation (AF) in athletes engaged in long-term endurance sports training compared with the general population. Although atrial anatomic adaptations, alterations in autonomic nervous system, chronic systemic inflammation and fibrosis have been proposed as potential mechanisms, they remain speculative. Medical therapy with long-term antiarrhythmic agents or ‘pill in the pocket’ medications is hampered by limitations, such as sports eligibility and interference with exercise tolerance. AF ablation represents a valid therapeutic option with results similar to these achieved in other patients. Nevertheless, further clinical trials are needed to confirm whether endurance sport practice affects the maintenance of sinus rhythm following catheter ablation of AF. PMID:26835059

Cardiac resynchronization therapy with His bundle pacing as a method of treatment of chronic heart failure in patients with permanent atrial fibrillation and left bundle branch block.

PubMed

Boczar, Krzysztof; Sławuta, Agnieszka; Ząbek, Andrzej; Dębski, Maciej; Gajek, Jacek; Lelakowski, Jacek; Małecka, Barbara

CRT is a therapeutic option for patients with heart failure, sinus rhythm, prolonged QRS complex duration and reduced ejection fraction. We present a case of 71-year-old woman with dilated cardiomyopathy, NYHA functional class III and AF. We implanted CRT combined with direct His-bundle pacing. The indication for such a therapy was a left bundle branch block with a QRS complex of 178ms and a left ventricular EF of 15%, left ventricular end-diastolic diameter (LVEDD) of 75mm. After 8months of follow-up the LVEDD was 60mm with EF 35-40%. Copyright © 2017. Published by Elsevier Inc.

MicroRNA-433 Dampens Glucocorticoid Receptor Signaling, Impacting Circadian Rhythm and Osteoblastic Gene Expression.

PubMed

Smith, Spenser S; Dole, Neha S; Franceschetti, Tiziana; Hrdlicka, Henry C; Delany, Anne M

2016-10-07

Serum glucocorticoids play a critical role in synchronizing circadian rhythm in peripheral tissues, and multiple mechanisms regulate tissue sensitivity to glucocorticoids. In the skeleton, circadian rhythm helps coordinate bone formation and resorption. Circadian rhythm is regulated through transcriptional and post-transcriptional feedback loops that include microRNAs. How microRNAs regulate circadian rhythm in bone is unexplored. We show that in mouse calvaria, miR-433 displays robust circadian rhythm, peaking just after dark. In C3H/10T1/2 cells synchronized with a pulse of dexamethasone, inhibition of miR-433 using a tough decoy altered the period and amplitude of Per2 gene expression, suggesting that miR-433 regulates rhythm. Although miR-433 does not directly target the Per2 3'-UTR, it does target two rhythmically expressed genes in calvaria, Igf1 and Hif1α. miR-433 can target the glucocorticoid receptor; however, glucocorticoid receptor protein abundance was unaffected in miR-433 decoy cells. Rather, miR-433 inhibition dramatically enhanced glucocorticoid signaling due to increased nuclear receptor translocation, activating glucocorticoid receptor transcriptional targets. Last, in calvaria of transgenic mice expressing a miR-433 decoy in osteoblastic cells (Col3.6 promoter), the amplitude of Per2 and Bmal1 mRNA rhythm was increased, confirming that miR-433 regulates circadian rhythm. miR-433 was previously shown to target Runx2, and mRNA for Runx2 and its downstream target, osteocalcin, were also increased in miR-433 decoy mouse calvaria. We hypothesize that miR-433 helps maintain circadian rhythm in osteoblasts by regulating sensitivity to glucocorticoid receptor signaling. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

MicroRNA-433 Dampens Glucocorticoid Receptor Signaling, Impacting Circadian Rhythm and Osteoblastic Gene Expression*

PubMed Central

Smith, Spenser S.; Dole, Neha S.; Franceschetti, Tiziana; Hrdlicka, Henry C.; Delany, Anne M.

2016-01-01

Serum glucocorticoids play a critical role in synchronizing circadian rhythm in peripheral tissues, and multiple mechanisms regulate tissue sensitivity to glucocorticoids. In the skeleton, circadian rhythm helps coordinate bone formation and resorption. Circadian rhythm is regulated through transcriptional and post-transcriptional feedback loops that include microRNAs. How microRNAs regulate circadian rhythm in bone is unexplored. We show that in mouse calvaria, miR-433 displays robust circadian rhythm, peaking just after dark. In C3H/10T1/2 cells synchronized with a pulse of dexamethasone, inhibition of miR-433 using a tough decoy altered the period and amplitude of Per2 gene expression, suggesting that miR-433 regulates rhythm. Although miR-433 does not directly target the Per2 3′-UTR, it does target two rhythmically expressed genes in calvaria, Igf1 and Hif1α. miR-433 can target the glucocorticoid receptor; however, glucocorticoid receptor protein abundance was unaffected in miR-433 decoy cells. Rather, miR-433 inhibition dramatically enhanced glucocorticoid signaling due to increased nuclear receptor translocation, activating glucocorticoid receptor transcriptional targets. Last, in calvaria of transgenic mice expressing a miR-433 decoy in osteoblastic cells (Col3.6 promoter), the amplitude of Per2 and Bmal1 mRNA rhythm was increased, confirming that miR-433 regulates circadian rhythm. miR-433 was previously shown to target Runx2, and mRNA for Runx2 and its downstream target, osteocalcin, were also increased in miR-433 decoy mouse calvaria. We hypothesize that miR-433 helps maintain circadian rhythm in osteoblasts by regulating sensitivity to glucocorticoid receptor signaling. PMID:27551048

Revealing a circadian clock in captive arctic-breeding songbirds, lapland longspurs (Calcarius lapponicus), under constant illumination.

PubMed

Ashley, Noah T; Ubuka, Takayoshi; Schwabl, Ingrid; Goymann, Wolfgang; Salli, Brady M; Bentley, George E; Buck, C Loren

2014-12-01

Most organisms in temperate or tropic regions employ the light-dark (LD) cycle as the primary Zeitgeber to synchronize circadian rhythms. At higher latitudes (>66°33'), continuous illumination during the summer presents a significant time-keeping dilemma for polar-adapted species. Lapland longspurs (Calcarius lapponicus), arctic-breeding migratory songbirds, are one of the few recorded species maintaining an intact diel rhythm in activity and plasma melatonin titers during polar summer. However, it is unknown whether rhythms are endogenous and entrain to low-amplitude polar Zeitgeber signals, such as daily variations in light intensity and the spectral composition of the sun (as measured by color temperature). Wild-caught male and female longspurs were brought into captivity, and locomotor activity was assessed using infrared detection. To examine if rhythms were endogenous, birds were exposed to constant bright light (LL; 1300 lux) or constant darkness (DD; 0.1 lux). All birds exhibited free-running activity rhythms in LL and DD, suggesting the presence of a functional circadian clock. Mean periods in LL (22.86 h) were significantly shorter than those in DD (23.5 h), in accordance with Aschoff's rule. No birds entrained to diel changes in light intensity, color temperature, or both. To examine endogenous molecular clock function, the Per2 gene was partially cloned in longspurs (llPer2) and transcripts were measured in hypothalamic tissue punches, eye, and liver using competitive polymerase chain reaction. Ocular llPer2 gene expression was periodic in LL and elevated at ZT24 (CT24) for LD or constant conditions (LL and DD), but llPer2 rhythmicity was not detected in hypothalamus or liver. Plasma melatonin was significantly lower in LL compared with LD or DD. In conclusion, rhythmic ocular Per2 expression and melatonin secretion may maintain the circadian activity rhythm across the polar day. © 2014 The Author(s).

Glucocorticoids mediate circadian timing in peripheral osteoclasts resulting in the circadian expression rhythm of osteoclast-related genes.

PubMed

Fujihara, Yuko; Kondo, Hisataka; Noguchi, Toshihide; Togari, Akifumi

2014-04-01

Circadian rhythms are prevalent in bone metabolism. However, the molecular mechanisms involved are poorly understood. Recently, we suggested that output signals from the suprachiasmatic nucleus (SCN) are transmitted from the master circadian rhythm to peripheral osteoblasts through β-adrenergic and glucocorticoid signaling. In this study, we examined how the master circadian rhythm is transmitted to peripheral osteoclasts and the role of clock gene in osteoclast. Mice were maintained under 12-hour light/dark periods and sacrificed at Zeitgeber times 0, 4, 8, 12, 16 and 20. mRNA was extracted from femur (cancellous bone) and analyzed for the expression of osteoclast-related genes and clock genes. Osteoclast-related genes such as cathepsin K (CTSK) and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) showed circadian rhythmicity like clock genes such as period 1 (PER1), PER2 and brain and muscle Arnt-like protein 1 (BMAL1). In an in vitro study, not β-agonist but glucocorticoid treatment remarkably synchronized clock and osteoclast-related genes in cultured osteoclasts. Chromatin immunoprecipitation (ChIP) assay showed the interaction between BMAL1 proteins and promoter region of CTSK and NFATc1. To examine whether endogenous glucocorticoids influence the osteoclast circadian rhythms, mice were adrenalectomized (ADX) and maintained under 12-hour light/dark periods at least two weeks before glucocorticoid injection. A glucocorticoid injection restarted the circadian expression of CTSK and NFATc1 in ADX mice. These results suggest that glucocorticoids mediate circadian timing to peripheral osteoclasts and osteoclast clock contributes to the circadian expression of osteoclast-related genes such as CTSK and NFATc1. Copyright © 2014 Elsevier Inc. All rights reserved.

Single-sensor system for spatially resolved, continuous, and multiparametric optical mapping of cardiac tissue

PubMed Central

Lee, Peter; Bollensdorff, Christian; Quinn, T. Alexander; Wuskell, Joseph P.; Loew, Leslie M.; Kohl, Peter

2011-01-01

Background Simultaneous optical mapping of multiple electrophysiologically relevant parameters in living myocardium is desirable for integrative exploration of mechanisms underlying heart rhythm generation under normal and pathophysiologic conditions. Current multiparametric methods are technically challenging, usually involving multiple sensors and moving parts, which contributes to high logistic and economic thresholds that prevent easy application of the technique. Objective The purpose of this study was to develop a simple, affordable, and effective method for spatially resolved, continuous, simultaneous, and multiparametric optical mapping of the heart, using a single camera. Methods We present a new method to simultaneously monitor multiple parameters using inexpensive off-the-shelf electronic components and no moving parts. The system comprises a single camera, commercially available optical filters, and light-emitting diodes (LEDs), integrated via microcontroller-based electronics for frame-accurate illumination of the tissue. For proof of principle, we illustrate measurement of four parameters, suitable for ratiometric mapping of membrane potential (di-4-ANBDQPQ) and intracellular free calcium (fura-2), in an isolated Langendorff-perfused rat heart during sinus rhythm and ectopy, induced by local electrical or mechanical stimulation. Results The pilot application demonstrates suitability of this imaging approach for heart rhythm research in the isolated heart. In addition, locally induced excitation, whether stimulated electrically or mechanically, gives rise to similar ventricular propagation patterns. Conclusion Combining an affordable camera with suitable optical filters and microprocessor-controlled LEDs, single-sensor multiparametric optical mapping can be practically implemented in a simple yet powerful configuration and applied to heart rhythm research. The moderate system complexity and component cost is destined to lower the threshold to broader application of functional imaging and to ease implementation of more complex optical mapping approaches, such as multiparametric panoramic imaging. A proof-of-principle application confirmed that although electrically and mechanically induced excitation occur by different mechanisms, their electrophysiologic consequences downstream from the point of activation are not dissimilar. PMID:21459161

Contact-Free Screening of Atrial Fibrillation by a Smartphone Using Facial Pulsatile Photoplethysmographic Signals.

PubMed

Yan, Bryan P; Lai, William H S; Chan, Christy K Y; Chan, Stephen Chun-Hin; Chan, Lok-Hei; Lam, Ka-Ming; Lau, Ho-Wang; Ng, Chak-Ming; Tai, Lok-Yin; Yip, Kin-Wai; To, Olivia T L; Freedman, Ben; Poh, Yukkee C; Poh, Ming-Zher

2018-04-05

We aimed to evaluate a novel method of atrial fibrillation (AF) screening using an iPhone camera to detect and analyze photoplethysmographic signals from the face without physical contact by extracting subtle beat-to-beat variations of skin color that reflect the cardiac pulsatile signal. Patients admitted to the cardiology ward of the hospital for clinical reasons were recruited. Simultaneous facial and fingertip photoplethysmographic measurements were obtained from 217 hospital inpatients (mean age, 70.3±13.9 years; 71.4% men) facing the front camera and with an index finger covering the back camera of 2 independent iPhones before a 12-lead ECG was recorded. Backdrop and background light intensity was monitored during signal acquisition. Three successive 20-second (total, 60 seconds) recordings were acquired per patient and analyzed for heart rate regularity by Cardiio Rhythm (Cardiio Inc, Cambridge, MA) smartphone application. Pulse irregularity in ≥1 photoplethysmographic readings or 3 uninterpretable photoplethysmographic readings were considered a positive AF screening result. AF was present on 12-lead ECG in 34.6% (n=75/217) patients. The Cardiio Rhythm facial photoplethysmographic application demonstrated high sensitivity (95%; 95% confidence interval, 87%-98%) and specificity (96%; 95% confidence interval, 91%-98%) in discriminating AF from sinus rhythm compared with 12-lead ECG. The positive and negative predictive values were 92% (95% confidence interval, 84%-96%) and 97% (95% confidence interval, 93%-99%), respectively. Detection of a facial photoplethysmographic signal to determine pulse irregularity attributable to AF is feasible. The Cardiio Rhythm smartphone application showed high sensitivity and specificity, with low negative likelihood ratio for AF from facial photoplethysmographic signals. The convenience of a contact-free approach is attractive for community screening and has the potential to be useful for distant AF screening. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Air embolism and maternal death from therapeutic abortion.

PubMed

Munsick, R A

1972-05-01

The case report of a fatal result in an abortion requested because X-ray diagnostic studies of the gallbladder and intestine had been made during an undiagnosed early pregnancy is presented. A uterine vacuum aspirator had not been purchased by the hospital. A portable laboratory vacuum pump with an appropriate suction trap was used. The apparatus had been used previously in several abortion cases. After dilatation of the cervix and insertion of the aspirating cannula, the pump was turned on. A sudden massive effusion of bloody froth issued from around the cannula. The cannula was removed immediately. It was found that the tubing had been incorrectly connected. The aspirator tube was connected with the pressure outlet of the pump. The tubing was then correctly placed and the uterus emptied. The patient was given succinyl choline, intubated, placed in the Trendelenburg position, and monitored cardiographically. About 30 seconds after the uterine insufflation blood pressure became unobtainable. The pulse slowed to 50 beats/minute and respiration diminished. Cardiac ausculation revealed no sounds. Respiration was maintained using oxygen through an endoctracheal tube. The pulse was still palpable and the EKG showed abnormal QRS complexes. Cyanosis then became evident. Closed chest cardiac massage was used for 1 minute but the patient became pulseless and QRS complexes were bizarre. Then the chest was opened and each ventricle was needled. From each ventricle of the distended heart air hissed under pressure through the needle vent site. The ascending aorta was needled and air escaped under pressure. Cardiac color and action improved when aided by massage. Iv isoproterenol and intracardiac epinephrine were given. An electric defibrillator converted the cardiac rhythm to a sinus rhythm. Norepinephirne brought about hypertension. Blood and albumin were given iv. The patient never regained consciousness. Tracheostomy and a feeding gastrostomy were required. Urinary and respiratory infections followed and the patient died after 2 1/2 months. Autopsy revealed tracheobronchitis, bronchopneumonia, and pulmonary edema. The brain showed extensive cerebral cortical necrosis. The heart was normal. This maternal death was preventable.

Inferior sinus venosus defect: echocardiographic diagnosis and surgical approach.

PubMed

Crystal, Matthew A; Al Najashi, Khaled; Williams, William G; Redington, Andrew N; Anderson, Robert H

2009-06-01

We sought to define the inferior sinus venosus defect anatomically and document successful surgical approaches. We identified all patients previously given a diagnosis of an inferior sinus venosus defect at the Hospital for Sick Children, Toronto, Canada, between 1982 and 2005 by interrogating the cardiology and cardiac surgery databases. We included those having interatrial communications in which 1 or more of the right pulmonary veins drained to the inferior caval vein but retained connection with the left atrium, the rims of the oval fossa, and the walls of the coronary sinus, both being intact. We identified 11 children who had an interatrial communication meeting the criteria for and undergoing surgical repair of an inferior sinus venosus defect. Median age was 1.2 years; 6 (55%) subjects were male, and none were cyanotic. Transthoracic echocardiographic analysis was performed preoperatively in all children, revealing right ventricular dilation in all. Surgical repair was accomplished with a pericardial patch. A complex baffle was needed in 3 children to maintain unobstructed inferior caval and pulmonary venous return. The echocardiographic diagnosis was complete in only 5 patients, but all diagnoses were correct since the year 2000. In all children the observations at surgical intervention showed that the defect was a venoatrial communication involving drainage of the right pulmonary veins to the inferior caval vein while retaining connection to the left atrium. Transthoracic echocardiographic analysis should remain the modality of choice for diagnosis of the inferior sinus venosus defect. We report excellent surgical results with a patch or baffle, correctly redirecting the anomalous venoatrial connections.

Symptomatic arrhythmias due to syringomyelia-induced severe autonomic dysfunction.

PubMed

Riedlbauchová, Lucie; Nedělka, Tomáš; Schlenker, Jakub

2014-10-01

Syringomyelia is characterized by cavity formation in the spinal cord, most often at C2-Th9 level. Clinical manifestation reflects extent and localization of the spinal cord injury. 20-year old woman was admitted for recurrent rest-related presyncopes with sudden manifestation. Paroxysms of sinus bradycardia with SA and AV blocks were repeatedly documented during symptoms. There was normal echocardiographic finding, (para) infectious etiology was not proved. Character of the ECG findings raised suspicion on neurogenic cause. Autonomic nervous system testing demonstrated abnormalities reflecting predominant sympathetic dysfunction. Suspicion on incipient myelopathy was subsequently confirmed by MRI, which discovered syringomyelia at Th5 level as the only pathology. A 52-year old man with hypotrophic quadruparesis resulting from perinatal brain injury was sent for 2-years lasting symptoms (sudden palpitation, sweating, muscle tightness, shaking) with progressive worsening. Symptoms occurred in association with sudden increase of sinus rhythm rate and blood pressure that were provoked by minimal physical activity. Presence of significant autonomic dysregulation with baroreflex hyperreactivity in orthostatic test and symptomatic postural orthostatic tachycardia with verticalization-associated hypertension were proved. MRI revealed syringomyelia at C7 and Th7 level affecting sympathetic centers at these levels. Sympathetic fibers dysfunction at C-Th spinal level may cause significant autonomic dysfunction with arrhythmic manifestation.

Normal Values for Heart Electrophysiology Parameters of Healthy Swine Determined on Electrophysiology Study.

PubMed

Noszczyk-Nowak, Agnieszka; Cepiel, Alicja; Janiszewski, Adrian; Pasławski, Robert; Gajek, Jacek; Pasławska, Urszula; Nicpoń, Józef

2016-01-01

Swine are a well-recognized animal model for human cardiovascular diseases. Despite the widespread use of porcine model in experimental electrophysiology, still no reference values for intracardiac electrical activity and conduction parameters determined during an invasive electrophysiology study (EPS) have been developed in this species thus far. The aim of the study was to develop a set of normal values for intracardiac electrical activity and conduction parameters determined during an invasive EPS of swine. The study included 36 healthy domestic swine (24-40 kg body weight). EPS was performed under a general anesthesia with midazolam, propofol and isoflurane. The reference values for intracardiac electrical activity and conduction parameters were calculated as arithmetic means ± 2 standard deviations. The reference values were determined for AH, HV and PA intervals, interatrial conduction time at its own and imposed rhythm, sinus node recovery time (SNRT), corrected sinus node recovery time (CSNRT), anterograde and retrograde Wenckebach points, atrial, atrioventricular node and ventricular refractory periods. No significant correlations were found between body weight and heart rate of the examined pigs and their electrophysiological parameters. The hereby presented reference values can be helpful in comparing the results of various studies, as well as in more accurately estimating the values of electrophysiological parameters that can be expected in a given experiment.

New advances in dynamic cardiomyoplasty: Doppler flow wire shows improved cardiac assistance in demand protocol.

PubMed

Rigatelli, Gianluca; Carraro, Ugo; Barbiero, Mario; Zanchetta, Mario; Pedon, Luigi; Dimopoulos, Konstantinos; Rigatelli, Giorgio; Maiolino, Pietro; Cobelli, Franco; Riccardi, Riccardo; Volta, Sergio Dalla

2002-01-01

No data have been published on real cardiac assistance with demand dynamic cardiomyoplasty. We tested the utility of a Doppler flow wire in measuring beat by beat aortic flow velocity and evaluating cardiac assistance in demand cardiomyoplasty patients. The technique was tested in seven patients (M/W = 6/1; age, 57.1+/-6.2 years; atrial fibrillation/ sinus rhythm = 1/6; New York Heart Association [NYHA] classification = 1.4+/-0.5). Measurements were done using a 0.018 inch peripheral Doppler flow wire advanced through a 5 French arterial femoral sheath. Three 1 minute periods with the stimulator off, and three 1 minute periods with clinical stimulation were recorded. We measured peak aortic flow velocity in all beats. Latissimus dorsi mechanogram was simultaneously recorded. Comparison between preoperative and follow-up data showed significantly higher values of tetanic fusion frequency and ejection fraction at follow-up, whereas mean NYHA class was significantly lower. Statistical analysis showed an increase in aortic flow velocity not only in the assisted versus rest period, but also in assisted versus unassisted beats (8.42+/-6.98% and 7.55+/-3.07%). A linear correlation was found between increase in flow velocity and latissimus dorsi wrap tetanic fusion frequency (r2 = 0.53). In demand dynamic cardiomyoplasty, systolic assistance is significant and correlated to the latissimus dorsi speed of contraction; a demand stimulation protocol maintains muscle properties and increases muscle performance.

Cardiorespiratory interactions in humans and animals: Rhythms for life.

PubMed

Elstad, Maja; O'Callaghan, Erin L; Smith, Alexander J; Ben-Tal, A; Ramchandra, Rohit

2018-03-09

The cardiorespiratory system exhibits oscillations from a range of sources. One of the most studied oscillations is heart rate variability, which is thought to be beneficial and can serve as an index of a healthy cardiovascular system. Heart rate variability is dampened in many diseases including depression, autoimmune diseases, hypertension and heart failure. Thus, understanding the interactions that lead to heart rate variability, and its physiological role, could help with prevention, diagnosis and treatment of cardiovascular diseases. In this review we consider three types of cardiorespiratory interactions; Respiratory Sinus Arrhythmia - variability in heart rate at the frequency of breathing, Cardioventilatory Coupling - synchronization between the heart beat and the onset of inspiration, and Respiratory Stroke Volume Synchronization - constant phase difference between the right and the left stroke volumes over one respiratory cycle. While the exact physiological role of these oscillations continues to be debated, the redundancies in the mechanisms responsible for its generation and its strong evolutionary conservation point to the importance of cardiorespiratory interactions. The putative mechanisms driving cardiorespiratory oscillations as well as the physiological significance of these oscillations will be reviewed. We suggest that cardiorespiratory interactions have the capacity to both dampen the variability in systemic blood flow as well as improve the efficiency of work done by the heart while maintaining physiological levels of arterial CO 2 . Given that reduction in variability is a prognostic indicator of disease, we argue that restoration of this variability via pharmaceutical or device-based approaches may be beneficial in prolonging life.

A review of the appropriate and inappropriate use of dronedarone: lessons learned from controlled studies and regulatory submission.

PubMed

Naccarelli, Gerald V; Wolbrette, Deborah L; Samii, Soraya; Banchs, Javier E; Penny-Peterson, Erica; Gonzalez, Mario D

2010-12-01

Dronedarone is a multichannel blocker with electrophysiologic effects similar to amiodarone. Dronedarone has been documented to prevent atrial fibrillation recurrences and also has efficacy in slowing the ventricular response during episodes of atrial fibrillation. However, in the ANDROMEDA trial, dronedarone was associated with increased mortality when tested in New York Heart Association (NYHA) III/IV patients with left ventricular ejection fractions of less than 35%, who also had a recent hospitalization for decompensated heart failure. When such high-risk patients with heart failure were excluded in the ATHENA trial, dronedarone treatment resulted in a statistical reduction in the composite primary end point of all-cause mortality or cardiovascular hospitalization. In ATHENA, dronedarone reduced cardiovascular hospitalizations even though in the DIONY-SOS trial dronedarone had less effect than amiodarone on suppressing atrial fibrillation recurrences. The most appropriate patients for treatment with dronedarone would be patients with a recent history of paroxysmal or persistent atrial fibrillation/atrial flutter (AF/AFL) that have associated risk factors per the inclusion criteria of ATHENA. Inappropriate patients would be those with class IV heart failure or recently hospitalized for heart failure within the last month from an acute decompensation, the main inclusion criteria in ANDROMEDA. Dronedarone is a novel, multichannel blocking antiarrhythmic agent that may have some pleiotropic effects in addition to its ability to suppress and maintain sinus rhythm and control the rate during AF/AFL recurrences.

Electrocardiographic left ventricular hypertrophy predicts recurrence of atrial arrhythmias after catheter ablation of paroxysmal atrial fibrillation.

PubMed

Li, Song-Nan; Wang, Lu; Dong, Jian-Zeng; Yu, Rong-Hui; Long, De-Yong; Tang, Ri-Bo; Sang, Cai-Hua; Jiang, Chen-Xi; Liu, Nian; Bai, Rong; Du, Xin; Ma, Chang-Sheng

2018-06-01

Left ventricular hypertrophy (LVH) is an independent predictor of new-onset atrial fibrillation. Whether LVH can predict the recurrence of arrhythmia after radiofrequency catheter ablation (RFCA) in patients with paroxysmal atrial fibrillation (PAF) remains unclear. PAF patients with baseline-electrocardiographic LVH has a higher recurrence rate after RFCA procedure compared with those without LVH. A total of 436 patients with PAF undergoing first RFCA were consecutively enrolled and clustered into 2 groups based on electrocardiogram (ECG) findings: non-ECG LVH (218 patients) and ECG LVH (218 patients). LVH was characterized by the Romhilt-Estes point score system; the score ≥5points were defined as LVH. At 42 months' (interquartile range, 18.0-60.0 months) follow-up after RFCA, 151 (69.3%) patients in the non-ECG LVH group and 108 (49.5%) patients in the ECG LVH group maintained sinus rhythm without using antiarrhythmic drugs (P < 0.001). Patients with ECG LVH tended to experience a much higher prevalence of stroke and recurrence of atrial arrhythmia episodes compared with those without ECG LVH (log-rank P < 0.001). Multivariate analysis found the presence of ECG LVH and left atrial diameter to be independent risk factors for recurrence after adjusting for confounding factors. The presence of ECG LVH was a strong and independent predictor of recurrence in patients with PAF following RFCA. © 2018 Wiley Periodicals, Inc.

Modified radial v/s biatrial maze for atrial fibrillation in rheumatic valvular heart surgery.

PubMed

Sayed, Sajid A; Katewa, Ashish; Srivastava, Vivek; Jana, Sujit; Patwardhan, Anil M

2014-01-01

Atrial fibrillation (AF) is commonest sustained atrial arrhythmia producing high morbidity. Although Cox's Maze III procedure cures AF in majority, reduced atrial transport function (ATF) is a concern. Radial approach with ablation lines radial from sinus node towards atrioventricular annulii and parallel to atrial coronary arteries, has shown better ATF. Single blind open randomized prospective study of 80 patients was undertaken in two groups (40 each) of modified Cox's maze III and modified radial approach, to evaluate conversion to normal sinus rhythm (NSR) and ATF. Patients undergoing surgery for rheumatic valvular heart disease with continuous AF were prospectively randomized. Ablation lines were created with radiofrequency (RF) bipolar coagulation with cryoablation for the isthmal lesions and coronary sinus. Results were compared at 6 months and ATF was evaluated by atrial filling fraction (AFF) and A/E ratio on echocardiography. The rate of conversion to NSR in both groups was statistically insignificant by Fisher's exact test (p > 0.05). ATF was better in modified radial approach compared to modified Cox's Maze III (A/E compared by unpaired t test:0.52 ± 0.08 v/s 0.36 ± 0.10; p < 0.05. AFF compared using Mann Whitney U test: median AFF for radial group was 23 v/s 20 for biatrial group; p < 0.05). In patients with AF undergoing rheumatic valvular surgery, radiofrequency radial approach is as effective as modified Cox's maze III for conversion to NSR with better atrial transport function. Copyright © 2014 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Thromboprophylaxis for Patients with High-risk Atrial Fibrillation and Flutter Discharged from the Emergency Department.

PubMed

Vinson, David R; Warton, E Margaret; Mark, Dustin G; Ballard, Dustin W; Reed, Mary E; Chettipally, Uli K; Singh, Nimmie; Bouvet, Sean Z; Kea, Bory; Ramos, Patricia C; Glaser, David S; Go, Alan S

2018-03-01

Many patients with atrial fibrillation or atrial flutter (AF/FL) who are high risk for ischemic stroke are not receiving evidence-based thromboprophylaxis. We examined anticoagulant prescribing within 30 days of receiving dysrhythmia care for non-valvular AF/FL in the emergency department (ED). This prospective study included non-anticoagulated adults at high risk for ischemic stroke (ATRIA score ≥7) who received emergency AF/FL care and were discharged home from seven community EDs between May 2011 and August 2012. We characterized oral anticoagulant prescribing patterns and identified predictors of receiving anticoagulants within 30 days of the index ED visit. We also describe documented reasons for withholding anticoagulation. Of 312 eligible patients, 128 (41.0%) were prescribed anticoagulation at ED discharge or within 30 days. Independent predictors of anticoagulation included age (adjusted odds ratio [aOR] 0.89 per year, 95% confidence interval [CI] 0.82-0.96); ED cardiology consultation (aOR 1.89, 95% CI [1.10-3.23]); and failure of sinus restoration by time of ED discharge (aOR 2.65, 95% CI [1.35-5.21]). Reasons for withholding anticoagulation at ED discharge were documented in 139 of 227 cases (61.2%), the most common of which were deferring the shared decision-making process to the patient's outpatient provider, perceived bleeding risk, patient refusal, and restoration of sinus rhythm. Approximately 40% of non-anticoagulated AF/FL patients at high risk for stroke who presented for emergency dysrhythmia care were prescribed anticoagulation within 30 days. Physicians were less likely to anticoagulate older patients and those with ED sinus restoration. Opportunities exist to improve rates of thromboprophylaxis in this high-risk population.

Management of the Upper Airway in Cystic Fibrosis

PubMed Central

Illing, Elisa A.; Woodworth, Bradford A.

2015-01-01

Purpose of Review Upper airway disease engenders significant morbidity for patients with cystic fibrosis and is increasingly recognized as having a much greater role in pulmonary outcomes and quality of life than originally believed. Widespread disparate therapeutic strategies for cystic fibrosis chronic rhinosinusitis underscore the absence of a standardized treatment paradigm. This review outlines the most recent evidence-based trends in the management of upper airway disease in cystic fibrosis. Recent Findings The unified airway theory proposes that the sinuses are a focus of initial bacterial colonization which seeds the lower airway and may play a large role in maintaining lung infections. Mounting evidence suggests more aggressive treatment of the sinuses may confer significant improvement in pulmonary disease and quality of life outcomes in cystic fibrosis patients. However, there is a lack of high-level evidence regarding medical and surgical management of cystic fibrosis chronic rhinosinusitis that makes generalizations difficult. Summary Well designed clinical trials with long-term follow-up concerning medical and surgical interventions for cystic fibrosis sinus disease are required to establish standardized treatment protocols, but increased interest in the sinuses as a bacterial reservoir for pulmonary infections has generated considerable attention. PMID:25250804

Cardiomyocyte Circadian Oscillations Are Cell-Autonomous, Amplified by β-Adrenergic Signaling, and Synchronized in Cardiac Ventricle Tissue

PubMed Central

Welsh, David K.

2016-01-01

Circadian clocks impact vital cardiac parameters such as blood pressure and heart rate, and adverse cardiac events such as myocardial infarction and sudden cardiac death. In mammals, the central circadian pacemaker, located in the suprachiasmatic nucleus of the hypothalamus, synchronizes cellular circadian clocks in the heart and many other tissues throughout the body. Cardiac ventricle explants maintain autonomous contractions and robust circadian oscillations of clock gene expression in culture. In the present study, we examined the relationship between intrinsic myocardial function and circadian rhythms in cultures from mouse heart. We cultured ventricular explants or dispersed cardiomyocytes from neonatal mice expressing a PER2::LUC bioluminescent reporter of circadian clock gene expression. We found that isoproterenol, a β-adrenoceptor agonist known to increase heart rate and contractility, also amplifies PER2 circadian rhythms in ventricular explants. We found robust, cell-autonomous PER2 circadian rhythms in dispersed cardiomyocytes. Single-cell rhythms were initially synchronized in ventricular explants but desynchronized in dispersed cells. In addition, we developed a method for long-term, simultaneous monitoring of clock gene expression, contraction rate, and basal intracellular Ca2+ level in cardiomyocytes using PER2::LUC in combination with GCaMP3, a genetically encoded fluorescent Ca2+ reporter. In contrast to robust PER2 circadian rhythms in cardiomyocytes, we detected no rhythms in contraction rate and only weak rhythms in basal Ca2+ level. In summary, we found that PER2 circadian rhythms of cardiomyocytes are cell-autonomous, amplified by adrenergic signaling, and synchronized by intercellular communication in ventricle explants, but we detected no robust circadian rhythms in contraction rate or basal Ca2+. PMID:27459195

[Effects of acupuncture on circadian rhythm of blood pressure in patients with essential hypertension].

PubMed

Lei, Yun; Jin, Jiu; Ban, Haipeng; Du, Yuzheng

2017-11-12

To observe the effects of acupuncture combined with medication on circadian rhythm of blood pressure in patients with essential hypertension. Sixty-four patients of essential hypertension were randomly divided into an observation group and a control group, 32 cases in each group. All the patients maintained original treatment (taking antihypertensive medication); the patients in the observation group were treated with acupuncture method of " Huoxue Sanfeng , Shugan Jianpi ", once a day, five times per week, for totally 6 weeks (30 times). The circadian rhythm of blood pressure and related dynamic parameters were observed before and after treatment in the two groups. (1) The differences of daytime average systolic blood pressure (dASBP), daytime average diastolic blood pressure (dADBP), nighttime average systolic blood pressure (nASBP) and circadian rhythm of systolic blood pressure before and after treatment were significant in the observation group (all P <0.05); the differences of circadian rhythm of blood pressure and related dynamic parameters before and after treatment were insignificant in the control group (all P >0.05). The nASBP and circadian rhythm of systolic blood pressure in the observation group were significantly different from those in the control group (all P <0.05). (2) After the treatment, the spoon-shaped rate of circadian rhythm of blood pressure in the observation group was higher than that in the control group ( P <0.05). The acupuncture combined with medication could effectively improve the circadian rhythm of blood pressure and related dynamic parameters in patients with essential hypertension.

Melanopsin resets circadian rhythms in cells by inducing clock gene Period1

NASA Astrophysics Data System (ADS)

Yamashita, Shuhei; Uehara, Tomoe; Matsuo, Minako; Kikuchi, Yo; Numano, Rika

2014-02-01

The biochemical, physiological and behavioral processes are under the control of internal clocks with the period of approximately 24 hr, circadian rhythms. The expression of clock gene Period1 (Per1) oscillates autonomously in cells and is induced immediately after a light pulse. Per1 is an indispensable member of the central clock system to maintain the autonomous oscillator and synchronize environmental light cycle. Per1 expression could be detected by Per1∷luc and Per1∷GFP plasmid DNA in which firefly luciferase and Green Fluorescence Protein were rhythmically expressed under the control of the mouse Per1 promoter in order to monitor mammalian circadian rhythms. Membrane protein, MELANOPSIN is activated by blue light in the morning on the retina and lead to signals transduction to induce Per1 expression and to reset the phase of circadian rhythms. In this report Per1 induction was measured by reporter signal assay in Per1∷luc and Per1∷GFP fibroblast cell at the input process of circadian rhythms. To the result all process to reset the rhythms by Melanopsin is completed in single cell like in the retina projected to the central clock in the brain. Moreover, the phase of circadian rhythm in Per1∷luc cells is synchronized by photo-activated Melanopsin, because the definite peak of luciferase activity in one dish was found one day after light illumination. That is an available means that physiological circadian rhythms could be real-time monitor as calculable reporter (bioluminescent and fluorescent) chronological signal in both single and groups of cells.

Keeping the rhythm: light/dark cycles during postharvest storage preserve the tissue integrity and nutritional content of leafy plants.

PubMed

Liu, John D; Goodspeed, Danielle; Sheng, Zhengji; Li, Baohua; Yang, Yiran; Kliebenstein, Daniel J; Braam, Janet

2015-03-27

The modular body structure of plants enables detached plant organs, such as postharvest fruits and vegetables, to maintain active responsiveness to environmental stimuli, including daily cycles of light and darkness. Twenty-four hour light/darkness cycles entrain plant circadian clock rhythms, which provide advantage to plants. Here, we tested whether green leafy vegetables gain longevity advantage by being stored under light/dark cycles designed to maintain biological rhythms. Light/dark cycles during postharvest storage improved several aspects of plant tissue performance comparable to that provided by refrigeration. Tissue integrity, green coloration, and chlorophyll content were generally enhanced by cycling of light and darkness compared to constant light or darkness during storage. In addition, the levels of the phytonutrient glucosinolates in kale and cabbage remained at higher levels over time when the leaf tissue was stored under light/dark cycles. Maintenance of the daily cycling of light and dark periods during postharvest storage may slow the decline of plant tissues, such as green leafy vegetables, improving not only appearance but also the health value of the crops through the maintenance of chlorophyll and phytochemical content after harvest.

Mechanisms of action of light on circadian rhythms in the monkey

NASA Technical Reports Server (NTRS)

Winget, C. M.; Rosenblatt, L. S.; DeRoshia, C. W.; Hetherington, N. W.

1970-01-01

Light is considered by many investigators to be the primary Zeitgeber for most physiologic rhythms. In order to study the effects on biorhythms of changing photoperiods and to provide information on the nature of the wave forms and the mechanisms of entrainment, unrestrained male monkeys (Cebus albifrons, Macaca nemestrina) were maintained in a sound-proofed environmental chamber. The Cebus was initially maintained on a 12L:12D schedule; it was subjected to a 180 degrees phase shift for 14 days, then returned to the original photoperiod. In two experiments (24 days; 27 days each) the same monkey was again maintained on a 12L:12D schedule which was gradually altered to a constant light environment. Deep body temperature (DBT) data were obtained with miniature radiotransmitters. Locomotor activity (LMA) was measured by strain gauges. Under the 12L:12D regimens the Macaca DBT cycles were uniform as to phase and wave form for over 60 weeks. These wave forms were analyzed by the use of periodogram and correlogram analyses and by fitting to the Volterra Integro-Differential Equation. Phase angle relationships between Zeitgeber and physiologic parameters were characterized. After the photoperiod phase shift the DBT cycle rephased in about 9 days. During the rephasing process the wave form changed. The shapes of the wave forms of DBT and activity were maintained with increasing light until an 18L:6D photoperiod was reached. The rhythms were entrained to the onset of darkness rather than lights on. Major and minor periods of LMA were detected. Hysteresis diagrams showed that DBT led the onset of major LA by 6 hr and the end of major activity by 2 hr.

ECG denoising using angular velocity as a state and an observation in an Extended Kalman Filter framework.

PubMed

Akhbari, Mahsa; Shamsollahi, Mohammad B; Jutten, Christian; Coppa, Bertrand

2012-01-01

In this paper an efficient filtering procedure based on Extended Kalman Filter (EKF) has been proposed. The method is based on a modified nonlinear dynamic model, previously introduced for the generation of synthetic ECG signals. The proposed method considers the angular velocity of ECG signal, as one of the states of an EKF. We have considered two cases for observation equations, in one case we have assumed a corresponding observation to angular velocity state and in the other case, we have not assumed any observations for it. Quantitative evaluation of the proposed algorithm on the MIT-BIH Normal Sinus Rhythm Database (NSRDB) shows that an average SNR improvement of 8 dB is achieved for an input signal of -4 dB.

United in prevention-electrocardiographic screening for chronic obstructive pulmonary disease.

PubMed

Lazovic, Biljana; Mazic, Sanja; Stajic, Zoran; Djelic, Marina; Zlatkovic-Svenda, Mirjana; Putnikovic, Biljana

2013-01-01

NONE DECLARED. P-wave abnormalities on the resting electrocardiogram have been associated with cardiovascular or pulmonary disease. So far, "Gothic" P wave and verticalization of the frontal plane axis is related to lung disease, particularly obstructive lung disease. We tested if inverted P wave in AVl as a lone criteria of P wave axis >70° could be screening tool for emphysema. 1095 routine electrocardiograms (ECGs) were reviewed which yielded 478 (82,1%) ECGs with vertical P-axis in sinus rhythm. Charts were reviewed for the diagnosis of COPD and emphysema based on medical history and pulmonary function tests. Electrocardiogram is very effective screening tool not only in cardiovascular field but in chronic obstructive pulmonary disease. The verticality of the P axis is usually immediately apparent, making electrocardiogram rapid screening test for emphysema.

No patch technique for complete atrioventricular canal repair.

PubMed

Aramendi, José Ignacio; Rodriguez, Miguel Angel; Luis, Teresa; Voces, Roberto

2006-08-01

We describe our initial experience with a new technique, consisting in direct closure of the ventricular septal defect component of the AV canal, by directly attaching the common bridging leaflets to the crest of the ventricular septum with interrupted sutures. After closure of the cleft, the ostium primum defect was closed with a running suture suturing the border of the septum primum to the newly created AV valve annulus. Three patients were operated upon. There was no mortality. Mean ischemic time was 39 min and mean pump time 77 min. All patients remained in sinus rhythm. At follow-up only trivial or mild mitral regurgitation was observed. This new technique permits the repair of complete AV canal without the need for any patch. It is fast, simple and reproducible.

Digoxin for atrial fibrillation and atrial flutter: A systematic review with meta-analysis and trial sequential analysis of randomised clinical trials

PubMed Central

Gluud, Christian; Jakobsen, Janus C.

2018-01-01

Background During recent years, systematic reviews of observational studies have compared digoxin to no digoxin in patients with atrial fibrillation or atrial flutter, and the results of these reviews suggested that digoxin seems to increase the risk of all-cause mortality regardless of concomitant heart failure. Our objective was to assess the benefits and harms of digoxin for atrial fibrillation and atrial flutter based on randomized clinical trials. Methods We searched CENTRAL, MEDLINE, Embase, LILACS, SCI-Expanded, BIOSIS for eligible trials comparing digoxin versus placebo, no intervention, or other medical interventions in patients with atrial fibrillation or atrial flutter in October 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were heart failure, stroke, heart rate control, and conversion to sinus rhythm. We performed both random-effects and fixed-effect meta-analyses and chose the more conservative result as our primary result. We used Trial Sequential Analysis (TSA) to control for random errors. We used GRADE to assess the quality of the body of evidence. Results 28 trials (n = 2223 participants) were included. All were at high risk of bias and reported only short-term follow-up. When digoxin was compared with all control interventions in one analysis, we found no evidence of a difference on all-cause mortality (risk ratio (RR), 0.82; TSA-adjusted confidence interval (CI), 0.02 to 31.2; I2 = 0%); serious adverse events (RR, 1.65; TSA-adjusted CI, 0.24 to 11.5; I2 = 0%); quality of life; heart failure (RR, 1.05; TSA-adjusted CI, 0.00 to 1141.8; I2 = 51%); and stroke (RR, 2.27; TSA-adjusted CI, 0.00 to 7887.3; I2 = 17%). Our analyses on acute heart rate control (within 6 hours of treatment onset) showed firm evidence of digoxin being superior compared with placebo (mean difference (MD), -12.0 beats per minute (bpm); TSA-adjusted CI, -17.2 to -6.76; I2 = 0%) and inferior compared with beta blockers (MD, 20.7 bpm; TSA-adjusted CI, 14.2 to 27.2; I2 = 0%). Meta-analyses on acute heart rate control showed that digoxin was inferior compared with both calcium antagonists (MD, 21.0 bpm; TSA-adjusted CI, -30.3 to 72.3) and with amiodarone (MD, 14.7 bpm; TSA-adjusted CI, -0.58 to 30.0; I2 = 42%), but in both comparisons TSAs showed that we lacked information. Meta-analysis on acute conversion to sinus rhythm showed that digoxin compared with amiodarone reduced the probability of converting atrial fibrillation to sinus rhythm, but TSA showed that we lacked information (RR, 0.54; TSA-adjusted CI, 0.13 to 2.21; I2 = 0%). Conclusions The clinical effects of digoxin on all-cause mortality, serious adverse events, quality of life, heart failure, and stroke are unclear based on current evidence. Digoxin seems to be superior compared with placebo in reducing the heart rate, but inferior compared with beta blockers. The long-term effect of digoxin is unclear, as no trials reported long-term follow-up. More trials at low risk of bias and low risk of random errors assessing the clinical effects of digoxin are needed. Systematic review registration PROSPERO CRD42016052935 PMID:29518134

High-frequency sarcomeric auto-oscillations induced by heating in living neonatal cardiomyocytes of the rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shintani, Seine A.; Oyama, Kotaro; Fukuda, Norio, E-mail: noriof@jikei.ac.jp

2015-02-06

Highlights: • We tested the effects of infra-red laser irradiation on cardiac sarcomere dynamics. • A rise in temperature (>∼38 °C) induced high-frequency sarcomeric auto-oscillations. • These oscillations occurred with and without blockade of intracellular Ca{sup 2+} stores. • Cardiac sarcomeres can play a role as a temperature-dependent rhythm generator. - Abstract: In the present study, we investigated the effects of infra-red laser irradiation on sarcomere dynamics in living neonatal cardiomyocytes of the rat. A rapid increase in temperature to >∼38 °C induced [Ca{sup 2+}]{sub i}-independent high-frequency (∼5–10 Hz) sarcomeric auto-oscillations (Hyperthermal Sarcomeric Oscillations; HSOs). In myocytes with the intactmore » sarcoplasmic reticular functions, HSOs coexisted with [Ca{sup 2+}]{sub i}-dependent spontaneous beating in the same sarcomeres, with markedly varying frequencies (∼10 and ∼1 Hz for the former and latter, respectively). HSOs likewise occurred following blockade of the sarcoplasmic reticular functions, with the amplitude becoming larger and the frequency lower in a time-dependent manner. The present findings suggest that in the mammalian heart, sarcomeres spontaneously oscillate at higher frequencies than the sinus rhythm at temperatures slightly above the physiologically relevant levels.« less

Circadian Disruption Changes Gut Microbiome Taxa and Functional Gene Composition.

PubMed

Deaver, Jessica A; Eum, Sung Y; Toborek, Michal

2018-01-01

Disrupted circadian rhythms and alterations of the gut microbiome composition were proposed to affect host health. Therefore, the aim of this research was to identify whether these events are connected and if circadian rhythm disruption by abnormal light-dark (LD) cycles affects microbial community gene expression and host vulnerability to intestinal dysfunction. Mice were subjected to either a 4-week period of constant 24-h light or of normal 12-h LD cycles. Stool samples were collected at the beginning and after the circadian rhythm disruption. A metatranscriptomic analysis revealed an increase in Ruminococcus torques , a bacterial species known to decrease gut barrier integrity, and a decrease in Lactobacillus johnsonii , a bacterium that helps maintain the intestinal epithelial cell layer, after circadian rhythm disruption. In addition, genes involved in pathways promoting host beneficial immune responses were downregulated, while genes involved in the synthesis and transportation of the endotoxin lipopolysaccharide were upregulated in mice with disrupted circadian cycles. Importantly, these mice were also more prone to dysfunction of the intestinal barrier. These results further elucidate the impact of light-cycle disruption on the gut microbiome and its connection with increased incidence of disease in response to circadian rhythm disturbances.

Circadian Disruption Changes Gut Microbiome Taxa and Functional Gene Composition

PubMed Central

Deaver, Jessica A.; Eum, Sung Y.; Toborek, Michal

2018-01-01

Disrupted circadian rhythms and alterations of the gut microbiome composition were proposed to affect host health. Therefore, the aim of this research was to identify whether these events are connected and if circadian rhythm disruption by abnormal light–dark (LD) cycles affects microbial community gene expression and host vulnerability to intestinal dysfunction. Mice were subjected to either a 4-week period of constant 24-h light or of normal 12-h LD cycles. Stool samples were collected at the beginning and after the circadian rhythm disruption. A metatranscriptomic analysis revealed an increase in Ruminococcus torques, a bacterial species known to decrease gut barrier integrity, and a decrease in Lactobacillus johnsonii, a bacterium that helps maintain the intestinal epithelial cell layer, after circadian rhythm disruption. In addition, genes involved in pathways promoting host beneficial immune responses were downregulated, while genes involved in the synthesis and transportation of the endotoxin lipopolysaccharide were upregulated in mice with disrupted circadian cycles. Importantly, these mice were also more prone to dysfunction of the intestinal barrier. These results further elucidate the impact of light-cycle disruption on the gut microbiome and its connection with increased incidence of disease in response to circadian rhythm disturbances. PMID:29706947

Trends in sinusitis research: a systematic review of extramural funding.

PubMed

Levy, Joshua M; Smith, Stephanie Shintani; Varshney, Rickul; Chang, Eugene H; Ramakrishnan, Vijay R; Ting, Jonathan Y; Bleier, Benjamin S

2017-11-01

Innovation represents a core value of the American Rhinologic Society (ARS), with multiple efforts to promote research in the advancement rhinologic care. We therefore sought to identify trends in extramural sinusitis funding and underutilized sources of support to facilitate future efforts. A systematic review of the National Institutes of Health (NIH) Research Portfolio Online Tools (RePORTER) database (fiscal year 1993 to 2017) was completed with the search strategy: ("chronic sinusitis" OR rhinosinusitis). All identified studies were accepted for review, with comparison to ARS membership rolls to identify studies supported by ARS investigators. Foundation awards were surveyed to identify and characterize additional sources of support. The systematic review identified 958 projects receiving NIH funding, of which 120 remain active. The percentage of sinusitis-related awards and total funding relative to all NIH awards increased over the past 10 years (2006 to 2016) from 0.06% (8 / 9128) and 0.09% ($2,151,152 / $3,358,338,602) to 0.87% (86 / 9540) and 0.90% ($37,201,095 / $4,300,145,614). Among active studies, 9 investigators maintain membership in the ARS and serve as principal investigator or project leader in 12 (10%) studies. ARS investigators received the greatest number of awards from the National Institute on Deafness and Other Communication Disrders (n = 8,66.7%), while only receiving 2.2% of awarded funding from the National Institute of Allergy and Infectious Diseases ($607,500/$26,873,022), the largest source of awards for sinusitis research. Support for sinusitis research is significantly growing, with the largest source of active funding not being fully utilized by members of the ARS. Further efforts to promote funding priorities among extramural sources is necessary to facilitate increased funding for ARS member initiatives. © 2017 ARS-AAOA, LLC.

Safety of transvenous low energy cardioversion of atrial fibrillation in patients with a history of ventricular tachycardia: effects of rate and repolarization time on proarrhythmic risk.

PubMed

Simons, G R; Newby, K H; Kearney, M M; Brandon, M J; Natale, A

1998-02-01

The objective of this study was to assess the safety and efficacy of transvenous low energy cardioversion of atrial fibrillation in patients with ventricular tachycardia and atrial fibrillation and to study the mechanisms of proarrhythmia. Previous studies have demonstrated that cardioversion of atrial fibrillation using low energy, R wave synchronized, direct current shocks applied between catheters in the coronary sinus and right atrium is feasible. However, few data are available regarding the risk of ventricular proarrhythmia posed by internal atrial defibrillation shocks among patients with ventricular arrhythmias or structural heart disease. Atrial defibrillation was performed on 32 patients with monomorphic ventricular tachycardia and left ventricular dysfunction. Shocks were administered during atrial fibrillation (baseline shocks), isoproterenol infusion, ventricular pacing, ventricular tachycardia, and atrial pacing. Baseline shocks were also administered to 29 patients with a history of atrial fibrillation but no ventricular arrhythmias. A total of 932 baseline shocks were administered. No ventricular proarrhythmia was observed after well-synchronized baseline shocks, although rare inductions of ventricular fibrillation occurred after inappropriate T wave sensing. Shocks administered during wide-complex rhythms (ventricular pacing or ventricular tachycardia) frequently induced ventricular arrhythmias, but shocks administered during atrial pacing at identical ventricular rates did not cause proarrhythmia. The risk of ventricular proarrhythmia after well-synchronized atrial defibrillation shocks administered during narrow-complex rhythms is low, even in patients with a history of ventricular tachycardia. The mechanism of proarrhythmia during wide-complex rhythms appears not to be related to ventricular rate per se, but rather to the temporal relationship between shock delivery and the repolarization time of the previous QRS complex.

Differential Impact of Net Atrioventricular Compliance on Clinical Outcomes in Patients with Mitral Stenosis According to Cardiac Rhythm.

PubMed

Cho, In-Jeong; Chang, Hyuk-Jae; Lee, Soo Yeon; Shim, Chi Young; Hong, Geu-Ru; Chung, Namsik

2017-06-01

Net atrioventricular compliance (Cn), a parameter for the net compliance of the left atrium and left ventricle, is known to be a useful predictor of outcomes in patients with mitral stenosis (MS). The present study aimed to evaluate whether the impact of Cn on symptom status and clinical outcomes, as well as its contribution toward systolic pulmonary artery pressure (SPAP), differed according to cardiac rhythm. We retrospectively reviewed patients (N = 308) with rheumatic pure MS. Doppler-derived Cn was calculated using planimetered mitral valve area and E-wave downslope of transmitral flow. The primary endpoint was defined as a composite of all-cause death, percutaneous mitral valvotomy, surgical mitral valve replacement, admission for heart failure, and stroke. Overall, there were 178 patients (58%) with sinus rhythm (SR) and 130 patients (42%) with atrial fibrillation (AF). In multivariable linear regression analysis, there was a significant independent association between Cn and SPAP in patients with SR (P = .014), but not in those with AF (P = .112). During a median follow-up of 38 months, 130 patients (27%) experienced the study endpoint. In multivariable Cox regression, high Cn was associated with a more favorable prognosis in patients with SR (hazard ratio = 0.83; 95% CI, 0.69-0.99; P = .038). Conversely, high Cn was not found to offset the burden of adverse clinical outcomes in those with AF (hazard ratio = 1.18; 95% CI, 0.99-1.40; P = .071). Cn appears to be associated with SPAP and clinical outcomes in MS patients with SR. The predictive role of Cn in patients with AF requires further clarification. Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Respiratory modulation of cardiovascular rhythms before and after short-duration human spaceflight.

PubMed

Verheyden, B; Beckers, F; Couckuyt, K; Liu, J; Aubert, A E

2007-12-01

Astronauts commonly return from space with altered short-term cardiovascular dynamics and blunted baroreflex sensitivity. Although many studies have addressed this issue, post-flight effects on the dynamic circulatory control remain incompletely understood. It is not clear how long the cardiovascular system needs to recover from spaceflight as most post-flight investigations only extended between a few days and 2 weeks. In this study, we examined the effect of short-duration spaceflight (1-2 weeks) on respiratory-mediated cardiovascular rhythms in five cosmonauts. Two paced-breathing protocols at 6 and 12 breaths min(-1) were performed in the standing and supine positions before spaceflight, and after 1 and 25 days upon return. Dynamic baroreflex function was evaluated by transfer function analysis between systolic pressure and the RR intervals. Post-flight orthostatic blood pressure control was preserved in all cosmonauts. In the standing position after spaceflight there was an increase in heart rate (HR) of approx. 20 beats min(-1) or more. Averaged for all five cosmonauts, respiratory sinus dysrhythmia and transfer gain reduced to 40% the day after landing, and had returned to pre-flight levels after 25 days. Low-frequency gain decreased from 6.6 (3.4) [mean (SD)] pre-flight to 3.9 (1.6) post-flight and returned to 5.7 (1.3) ms mmHg(-1) after 25 days upon return to Earth. Unlike alterations in the modulation of HR, blood pressure dynamics were not significantly different between pre- and post-flight sessions. Our results indicate that short-duration spaceflight reduces respiratory modulation of HR and decreases cardiac baroreflex gain without affecting post-flight arterial blood pressure dynamics. Altered respiratory modulation of human autonomic rhythms does not persist until 25 days upon return to Earth.

Exploiting periodicity to extract the atrial activity in atrial arrhythmias

NASA Astrophysics Data System (ADS)

Llinares, Raul; Igual, Jorge

2011-12-01

Atrial fibrillation disorders are one of the main arrhythmias of the elderly. The atrial and ventricular activities are decoupled during an atrial fibrillation episode, and very rapid and irregular waves replace the usual atrial P-wave in a normal sinus rhythm electrocardiogram (ECG). The estimation of these wavelets is a must for clinical analysis. We propose a new approach to this problem focused on the quasiperiodicity of these wavelets. Atrial activity is characterized by a main atrial rhythm in the interval 3-12 Hz. It enables us to establish the problem as the separation of the original sources from the instantaneous linear combination of them recorded in the ECG or the extraction of only the atrial component exploiting the quasiperiodic feature of the atrial signal. This methodology implies the previous estimation of such main atrial period. We present two algorithms that separate and extract the atrial rhythm starting from a prior estimation of the main atrial frequency. The first one is an algebraic method based on the maximization of a cost function that measures the periodicity. The other one is an adaptive algorithm that exploits the decorrelation of the atrial and other signals diagonalizing the correlation matrices at multiple lags of the period of atrial activity. The algorithms are applied successfully to synthetic and real data. In simulated ECGs, the average correlation index obtained was 0.811 and 0.847, respectively. In real ECGs, the accuracy of the results was validated using spectral and temporal parameters. The average peak frequency and spectral concentration obtained were 5.550 and 5.554 Hz and 56.3 and 54.4%, respectively, and the kurtosis was 0.266 and 0.695. For validation purposes, we compared the proposed algorithms with established methods, obtaining better results for simulated and real registers.

Maintained benefits and improved survival of dynamic cardiomyoplasty by activity-rest stimulation: 5-year results of the Italian trial on "demand" dynamic cardiomyoplasty.

PubMed

Rigatelli, Gianluca; Barbiero, Mario; Rigatelli, Giorgio; Riccardi, Roberto; Cobelli, Franco; Cotogni, Angelo; Bandello, Attilio; Carraro, Ugo

2003-01-01

Latissimus dorsi (LD) muscular degeneration caused by continuous electrical stimulation has been the main cause of the poor results of dynamic cardiomyoplasty (DCMP) and its exclusion from the recent international guidelines on heart failure. To avoid full transformation of the LD and to improve results, a new stimulation protocol was developed; fewer impulses per day are delivered, providing the LD wrap with daily periods of rest ("demand" stimulation), based on a heart rate cut-off. The aim of this work is to report the results at 5 years of follow-up of the Italian Trial of Demand Dynamic Cardiomyoplasty and to discuss their impact on the destiny of this type of cardiac assistance. Twelve patients with dilated myocardiopathy (M/F=11/1, mean age 58.2+/-5.8 years, sinus rhythm/atrial fibrillation=11/1) were submitted during the period 1993-1996 to DCMP and at different intervals to demand protocol. Clinical, echocardiographic, mechanographic and cardiac invasive assessments were scheduled before initiating the demand protocol and during the follow-up at 0, 6 and every 12 months. The mean duration of follow-up was 40.2+/-13.8 months (range 18-64). There were no perioperative deaths. The demand stimulation protocol showed a decrease in 5 years in New York Health Association (NYHA) class (3.17+/-0.38-1.67+/-0.77, P=0.0001), an improvement of left ventricular ejection fraction (22.6+/-4.38-32.0+/-7.0, P<0.001), a 5-year actuarial survival of 83.3% (one patient was switched to heart transplantation programme due to clinical worsening and another one died of massive pulmonary embolism). Demand DCMP maintains over time LD muscular properties, enhances clinical benefits and improves survival of DCMP, thus reopening the debate whether this type of treatment should be considered in patients with end-stage heart failure.

Circadian Rhythm of Glomerular Filtration and Solute Handling Related to Nocturnal Enuresis.

PubMed

Dossche, L; Raes, A; Hoebeke, P; De Bruyne, P; Vande Walle, J

2016-01-01

Although nocturnal polyuria in patients with monosymptomatic enuresis can largely be explained by the decreased nocturnal vasopressin secretion hypothesis, other circadian rhythms in the kidney also seem to have a role. We recently documented an absent day/night rhythm in a subgroup of desmopressin refractory cases. We explore the importance of abnormal circadian rhythm of glomerular filtration and tubular (sodium, potassium) parameters in patients with monosymptomatic enuresis. In this retrospective study of a tertiary enuresis population we collected data subsequent to a standardized screening (International Children's Continence Society questionnaire), 14-day diary for nocturnal enuresis and diuresis, and 24-hour concentration profile. The study population consisted of 139 children with nocturnal enuresis who were 5 years or older. Children with nonmonosymptomatic nocturnal enuresis were used as controls. There was a maintained circadian rhythm of glomerular filtration, sodium, osmotic excretion and diuresis rate in children with monosymptomatic and nonmonosymptomatic nocturnal enuresis, and there was no difference between the 2 groups. Secondary analysis revealed that in patients with nocturnal polyuria (with monosymptomatic or nonmonosymptomatic nocturnal enuresis) circadian rhythm of glomerular filtration, sodium and osmotic excretion, and diuresis rate was diminished in contrast to those without nocturnal polyuria (p <0.001). Circadian rhythm of the kidney does not differ between patients with nonmonosymptomatic and monosymptomatic enuresis. However, the subgroup with enuresis and nocturnal polyuria has a diminished circadian rhythm of nocturnal diuresis, sodium excretion and glomerular filtration in contrast to children without nocturnal polyuria. This observation cannot be explained by the vasopressin theory alone. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Effects of photophase illuminance on locomotor activity, urine production and urinary 6-sulfatoxymelatonin in nocturnal and diurnal South African rodents.

PubMed

van der Merwe, Ingrid; Oosthuizen, Maria K; Ganswindt, Andre; Haim, Abraham; Bennett, Nigel C

2017-05-01

Effects of photophase illuminance (1, 10, 100 and 330 lx of white incandescent lighting) on daily rhythms of locomotor activity, urine production and 6-sulfatoxymelatonin (6-SMT; 10 versus 330 lx) were studied in nocturnal Namaqua rock mice ( Micaelamys namaquensis ) and diurnal four-striped field mice ( Rhabdomys pumilio ). Micaelamys namaquensis was consistently nocturnal (∼90-94% nocturnal activity), whereas considerable individual variation marked activity profiles in R. pumilio , but with activity mostly pronounced around twilight (∼55-66% diurnal activity). The amplitude of daily activity was distinctly affected by light intensity and this effect was greater in M. namaquensis than in R. pumilio Only M. namaquensis displayed a distinctive daily rhythm of urine production, which correlated with its activity rhythm. Mean daily urine production appeared to be attenuated under dim photophase conditions, particularly in R. pumilio The results suggest that the circadian regulation of locomotor activity and urine production possesses separate sensitivity thresholds to photophase illuminance. Micaelamys namaquensis expressed a significant daily 6-SMT rhythm that peaked during the late night, but the rhythm was attenuated by the brighter photophase cycle (330 lx). Rhabdomys pumilio appeared to express an ultradian 6-SMT rhythm under both lighting regimes with comparable mean daily 6-SMT values, but with different temporal patterns. It is widely known that a natural dark phase which is undisturbed by artificial light is essential for optimal circadian function. Here, we show that light intensity during the photophase also plays a key role in maintaining circadian rhythms in rodents, irrespective of their temporal activity rhythm. © 2017. Published by The Company of Biologists Ltd.

Influence of atrial fibrillation on plasma von willebrand factor, soluble E-selectin, and N-terminal pro B-type natriuretic peptide levels in systolic heart failure.

PubMed

Freestone, Bethan; Gustafsson, Finn; Chong, Aun Yeong; Corell, Pernille; Kistorp, Caroline; Hildebrandt, Per; Lip, Gregory Y H

2008-05-01

Endothelial dysfunction is present in patients with heart failure (HF) due to left ventricular systolic dysfunction, as well as in patients with atrial fibrillation (AF) who have normal cardiac function. It is unknown whether AF influences the degree of endothelial dysfunction in patients with systolic HF. We measured levels of plasma von Willebrand factor (vWF) and E-selectin (as indexes of endothelial damage/dysfunction and endothelial activation, respectively; both enzyme-linked immunosorbent assay) in patients with AF and HF (AF-HF), who were compared to patients with sinus rhythm and HF (SR-HF), as well as in age-matched, healthy, control subjects. We also assessed the relationship of vWF and E-selectin to plasma N-terminal pro B-type natriuretic peptide (NTpro-BNP), a marker for HF severity and prognosis. One hundred ninety patients (73% men; mean age, 69.0 +/- 10.1 years [+/- SD]) with systolic HF were studied, who were compared to 117 healthy control subjects: 52 subjects (27%) were in AF, while 138 subjects (73%) were in sinus rhythm. AF-HF patients were older than SR-HF patients (p = 0.046), but left ventricular ejection fraction and New York Heart Association class were similar. There were significant differences in NT-proBNP (p < 0.0001) and plasma vWF (p = 0.003) between patients and control subjects. On Tukey post hoc analysis, AF-HF patients had significantly increased NT-proBNP (p < 0.001) and vWF (p = 0.0183) but not E-selectin (p = 0.071) levels when compared to SR-HF patients. On multivariate analysis, the presence of AF was related to plasma vWF levels (p = 0.018). Plasma vWF was also significantly correlated with NT-proBNP levels (Spearman r = 0.139; p = 0.017). There is evidence of greater endothelial damage/dysfunction in AF-HF patients when compared to SR-HF patients. The clinical significance of this is unclear but may have prognostic value.

Heart rate variability parameters in horses distinguish atrial fibrillation from sinus rhythm before and after successful electrical cardioversion.

PubMed

Broux, B; De Clercq, D; Decloedt, A; Ven, S; Vera, L; van Steenkiste, G; Mitchell, K; Schwarzwald, C; van Loon, G

2017-11-01

Atrial fibrillation (AF) is the most common pathological arrhythmia in horses. After successful treatment, recurrence is common. Heart rate monitors are easily applicable in horses and some devices offer basic heart rate variability (HRV) calculations. If HRV can be used to distinguish between AF and sinus rhythm (SR), this could become a monitoring tool for horses at risk for recurrence of AF. The purpose of this study was to assess whether in horses AF (before cardioversion) and SR (after cardioversion) can be differentiated based upon HRV parameters. Cohort study with internal controls. Six HRV parameters were determined in 20 horses, both in AF and in SR, at rest (2- and 5-min and 1- and 4-h recordings) and during exercise (walk and trot, 2-min recordings). Time-domain (standard deviation of the NN intervals, root mean squared successive differences in NN intervals and triangular index), frequency domain (low/high frequency ratio) and nonlinear parameters (standard deviation of the Poincaré plot [SD]1 and SD2) were used. Statistical analysis was done using paired Wilcoxon signed rank tests and receiver operating characteristic curves. HRV was higher during AF compared to SR. Results for the detection of AF were good (area under the receiver operating characteristic curve [AUC] 0.8-1) for most HRV parameters. Root mean squared successive differences in NN intervals and SD1 yielded the best results (AUC 0.9-1). Sensitivity and specificity were high for all parameters at all recordings, but highest during exercise. Although AUCs improved with longer recordings, short recordings were also good (AUC 0.8-1) for the detection of AF. In horses with frequent second degree atrioventricular block, HRV at rest is increased and recordings at walk or trot are recommended. Animals served as their own controls and there was no long-term follow-up to identify AF recurrence. AF (before cardioversion) and SR (after cardioversion) could be distinguished with HRV. This technique has promise as a monitoring tool in horses at risk for AF development. © 2017 EVJ Ltd.

Delta of the local ventriculo-atrial intervals at the septal location to differentiate tachycardia using septal accessory pathways from atypical atrioventricular nodal re-entry.

PubMed

Calvo, David; Pérez, Diego; Rubín, José; García, Daniel; Ávila, Pablo; Javier García-Fernández, F; Pachón, Marta; Bravo, Loreto; Hernández, Jesús; Miracle, Ángel L; Valverde, Irene; Gozalez-Vasserot, Mar; Árias, Miguel Ángel; Jimenez-Candíl, Javier; Morís, César

2018-01-02

Tachycardia mediated by septal accessory pathways (AP) and atypical atrioventricular nodal re-entry (AVNRT) require careful electrophysiologic evaluation for differential diagnosis. We aim to describe the differential behaviour of local ventriculo-atrial (VA) intervals which predicts the tachycardia mechanism. The local VA intervals at the para-Hisian septum were measured under three different situations: (i) tachycardia; (ii) sustained entrainment from the right ventricular apex (RVA); and (iii) continuous pacing from the RVA during sinus rhythm. Differences were computed as follows: Δ-VAentr = VA during entrainment - VA during tachycardia; and Δ-VApac = VA while pacing during sinus rhythm - VA during tachycardia. In contrast to AVNRT, we hypothesized that an invariable retrograde conduction through the septal AP will keep the result of the subtractions close to 0 ms in cases of ortodromic atrioventricular re-entrant tachycardia (AVRT). We analysed 55 atypical AVNRT (45% posterior type) and 82 AVRT (10 anteroseptal, 18 para-Hisian, 12 mid-septal, and 42 posteroseptal). Δ-VAentr was longer for AVNRT (98.5 ± 40.3 ms) compared with septal AP (-5.7 ± 19.3 ms; P < 0.001). A value of 50 ms showed 98.7% sensitivity and 92% specificity (AUC 0.99; 95% CI 0.98-1). According to physiological criteria, a negative Δ-VAentr remains unobserved in the case of AVNRT (positive predictive value 100% for septal AP). Δ-VApac was also longer for AVNRT (66.5 ± 14.6 ms) compared with septal AP (-9.7 ± 3.3 ms; P < 0.001). A value of 50 ms showed 100% sensitivity and 74% specificity (AUC 0.86; 95% CI 0.76-0.93). Delta of the local VA intervals enables distinction between atypical AVNRT and AVRT mediated by septal AP. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.

Effect of age and sex on efficacy and tolerability of β blockers in patients with heart failure with reduced ejection fraction: individual patient data meta-analysis

PubMed Central

Manzano, Luis; Krum, Henry; Rosano, Giuseppe; Holmes, Jane; Altman, Douglas G; Collins, Peter D; Packer, Milton; Wikstrand, John; Coats, Andrew J S; Cleland, John G F; Kirchhof, Paulus; von Lueder, Thomas G; Rigby, Alan S; Andersson, Bert; Lip, Gregory YH; van Veldhuisen, Dirk J; Shibata, Marcelo C; Wedel, Hans; Böhm, Michael; Flather, Marcus D

2016-01-01

Objectives To determine the efficacy and tolerability of β blockers in a broad age range of women and men with heart failure with reduced ejection fraction (HFrEF) by pooling individual patient data from placebo controlled randomised trials. Design Prospectively designed meta-analysis of individual patient data from patients aged 40-85 in sinus rhythm at baseline, with left ventricular ejection fraction <0.45. Participants 13 833 patients from 11 trials; median age 64; 24% women. Main outcome measures The primary outcome was all cause mortality; the major secondary outcome was admission to hospital for heart failure. Analysis was by intention to treat with an adjusted one stage Cox proportional hazards model. Results Compared with placebo, β blockers were effective in reducing mortality across all ages: hazard ratios were 0.66 (95% confidence interval 0.53 to 0.83) for the first quarter of age distribution (median age 50); 0.71 (0.58 to 0.87) for the second quarter (median age 60); 0.65 (0.53 to 0.78) for the third quarter (median age 68); and 0.77 (0.64 to 0.92) for the fourth quarter (median age 75). There was no significant interaction when age was modelled continuously (P=0.1), and the absolute reduction in mortality was 4.3% over a median follow-up of 1.3 years (number needed to treat 23). Admission to hospital for heart failure was significantly reduced by β blockers, although this effect was attenuated at older ages (interaction P=0.05). There was no evidence of an interaction between treatment effect and sex in any age group. Drug discontinuation was similar regardless of treatment allocation, age, or sex (14.4% in those give β blockers, 15.6% in those receiving placebo). Conclusion Irrespective of age or sex, patients with HFrEF in sinus rhythm should receive β blockers to reduce the risk of death and admission to hospital. Registration PROSPERO CRD42014010012; Clinicaltrials.gov NCT00832442. PMID:27098105

Characteristics of atrial fibrillation cycle length predict restoration of sinus rhythm by catheter ablation.

PubMed

Di Marco, Luigi Yuri; Raine, Daniel; Bourke, John P; Langley, Philip

2013-09-01

Successful termination of atrial fibrillation (AF) during catheter ablation (CA) is associated with arrhythmia-free follow-up. Preablation factors such as mean atrial fibrillation cycle length (AFCL) predict the likelihood of AF termination during ablation but recurring patterns and AFCL stability have not been evaluated. To investigate novel predictors of acute and postoperative ablation outcomes from intracardiac electrograms: (1) recurring AFCL patterns and (2) localization index (LI) of the instantaneous fibrillatory rate distribution. Sixty-two patients with AF (32 paroxysmal AF; 45 men; age 57 ± 10 years) referred for CA were enrolled. One-minute electrogram was recorded from coronary sinus (CS; 5 bipoles) and right atrial appendage (HRA; 2 bipoles). Atrial activations were detected automatically to derive the AFCL and instantaneous fibrillatory rate (inverse of AFCL) time series. Recurring AFCL patterns were quantified by using recurrence plot indices (RPIs): percentage determinism, entropy of determinism, and maximum diagonal length. AFCL stability was determined by using the LI. The CA outcome predictivity of individual indices was assessed. Patients with terminated atrial fibrillation (T-AF) had higher RPI (P < .05 in CS7-8) and LI than did those with nonterminated atrial fibrillation (P < .005 in CS3-4; P < .05 in CS5-6, CS7-8, and HRA). Patients free of arrhythmia after 3-month follow-up had higher RPI and LI (all P < .05 in CS7-8). All indices except percentage determinism predicted T-AF in CS7-8 (area under the curve [AUC] ≥ 0.71; odds ratio [OR] ≥ 4.50; P < .05). The median AFCL and LI predicted T-AF in HRAD (AUC ≥ 0.75; OR ≥ 7.76; P < .05). The RPI and LI predicted 3-month follow-up in CS7-8 (AUC ≥ 0.68; OR ≥ 4.17; P < .05). AFCL recurrence and stability indices could be used in selecting patients more likely to benefit from CA. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Pacing as a Treatment for Reflex-Mediated (Vasovagal, Situational, or Carotid Sinus Hypersensitivity) Syncope: A Systematic Review for the 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

PubMed

Varosy, Paul D; Chen, Lin Y; Miller, Amy L; Noseworthy, Peter A; Slotwiner, David J; Thiruganasambandamoorthy, Venkatesh

2017-08-01

To determine, using systematic review of the biomedical literature, whether pacing reduces risk of recurrent syncope and relevant clinical outcomes among adult patients with reflex-mediated syncope. MEDLINE (through PubMed), EMBASE, and the Cochrane Central Register of Controlled Trials (through October 7, 2015) were searched for randomized trials and observational studies examining pacing and syncope, and the bibliographies of known systematic reviews were also examined. Studies were rejected for poor-quality study methods and for the lack of the population, intervention, comparator, or outcome(s) of interest. Of 3,188 citations reviewed, 10 studies met the inclusion criteria for systematic review, including a total of 676 patients. These included 9 randomized trials and 1 observational study. Of the 10 studies, 4 addressed patients with carotid sinus hypersensitivity, and the remaining 6 addressed vasovagal syncope. Among the 6 open-label (unblinded) studies, we found that pacing was associated with a 70% reduction in recurrent syncope (relative risk [RR]: 0.30; 95% confidence interval [CI]: 0.15-0.60). When the 2 analyzable studies with double-blinded methodology were considered separately, there was no clear benefit (RR: 0.73; 95% CI: 0.25-2.1), but confidence intervals were wide. The strongest evidence was from the randomized, double-blinded ISSUE-3 (Third International Study on Syncope of Uncertain Etiology) trial, which demonstrated a benefit of pacing among patients with recurrent syncope and asystole documented by implantable loop recorder. There are limited data with substantive evidence of outcome ascertainment bias, and only 2 studies with a double-blinded study design have been conducted. The evidence does not support the use of pacing for reflex-mediated syncope beyond patients with recurrent vasovagal syncope and asystole documented by implantable loop recorder. Copyright © 2017 American College of Cardiology Foundation, American Heart Association, Inc., and Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Pacing as a treatment for reflex-mediated (vasovagal, situational, or carotid sinus hypersensitivity) syncope: A systematic review for the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

PubMed

Varosy, Paul D; Chen, Lin Y; Miller, Amy L; Noseworthy, Peter A; Slotwiner, David J; Thiruganasambandamoorthy, Venkatesh

2017-08-01

To determine, using systematic review of the biomedical literature, whether pacing reduces risk of recurrent syncope and relevant clinical outcomes among adult patients with reflex-mediated syncope. MEDLINE (through PubMed), EMBASE, and the Cochrane Central Register of Controlled Trials (through October 7, 2015) were searched for randomized trials and observational studies examining pacing and syncope, and the bibliographies of known systematic reviews were also examined. Studies were rejected for poor-quality study methods and for the lack of the population, intervention, comparator, or outcome(s) of interest. Of 3,188 citations reviewed, 10 studies met the inclusion criteria for systematic review, including a total of 676 patients. These included 9 randomized trials and 1 observational study. Of the 10 studies, 4 addressed patients with carotid sinus hypersensitivity, and the remaining 6 addressed vasovagal syncope. Among the 6 open-label (unblinded) studies, we found that pacing was associated with a 70% reduction in recurrent syncope (relative risk [RR]: 0.30; 95% confidence interval [CI]: 0.15-0.60). When the 2 analyzable studies with double-blinded methodology were considered separately, there was no clear benefit (RR: 0.73; 95% CI: 0.25-2.1), but confidence intervals were wide. The strongest evidence was from the randomized, double-blinded ISSUE-3 (Third International Study on Syncope of Uncertain Etiology) trial, which demonstrated a benefit of pacing among patients with recurrent syncope and asystole documented by implantable loop recorder. There are limited data with substantive evidence of outcome ascertainment bias, and only 2 studies with a double-blinded study design have been conducted. The evidence does not support the use of pacing for reflex-mediated syncope beyond patients with recurrent vasovagal syncope and asystole documented by implantable loop recorder. Copyright © 2017 American College of Cardiology Foundation, American Heart Association, Inc., and Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Pacing as a Treatment for Reflex-Mediated (Vasovagal, Situational, or Carotid Sinus Hypersensitivity) Syncope: A Systematic Review for the 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

PubMed

Varosy, Paul D; Chen, Lin Y; Miller, Amy L; Noseworthy, Peter A; Slotwiner, David J; Thiruganasambandamoorthy, Venkatesh

2017-08-01

To determine, using systematic review of the biomedical literature, whether pacing reduces risk of recurrent syncope and relevant clinical outcomes among adult patients with reflex-mediated syncope. MEDLINE (through PubMed), EMBASE, and the Cochrane Central Register of Controlled Trials (through October 7, 2015) were searched for randomized trials and observational studies examining pacing and syncope, and the bibliographies of known systematic reviews were also examined. Studies were rejected for poor-quality study methods and for the lack of the population, intervention, comparator, or outcome(s) of interest. Of 3188 citations reviewed, 10 studies met the inclusion criteria for systematic review, including a total of 676 patients. These included 9 randomized trials and 1 observational study. Of the 10 studies, 4 addressed patients with carotid sinus hypersensitivity, and the remaining 6 addressed vasovagal syncope. Among the 6 open-label (unblinded) studies, we found that pacing was associated with a 70% reduction in recurrent syncope (relative risk [RR]: 0.30; 95% confidence interval [CI]: 0.15-0.60). When the 2 analyzable studies with double-blinded methodology were considered separately, there was no clear benefit (RR: 0.73; 95% CI: 0.25-2.1), but confidence intervals were wide. The strongest evidence was from the randomized, double-blinded ISSUE-3 (Third International Study on Syncope of Uncertain Etiology) trial, which demonstrated a benefit of pacing among patients with recurrent syncope and asystole documented by implantable loop recorder. There are limited data with substantive evidence of outcome ascertainment bias, and only 2 studies with a double-blinded study design have been conducted. The evidence does not support the use of pacing for reflex-mediated syncope beyond patients with recurrent vasovagal syncope and asystole documented by implantable loop recorder. © 2017 by the American College of Cardiology Foundation, the American Heart Association, Inc., and the Heart Rhythm Society.

Impact of heart rate in atrial fibrillation versus sinus rhythm on mortality in octogenarian patients with acute coronary syndrome

PubMed Central

Li, Shijun; Barywani, Salim; Fu, Michael

2017-01-01

Introduction Association of heart rate (HR) with mortality in patients with acute coronary syndrome (ACS) and aged ≥ 80 years are underrepresented in clinical trials. We therefore aimed to investigate the association of HR in atrial fibrillation (AF) versus sinus rhythm (SR) with all-cause mortality in octogenarian patients with ACS. Methods A total of 336 patients with ACS patients and aged ≥ 80 years were enrolled into the current study. The end point of interest was death from any cause. Association of HR in AF versus SR with mortality was analyzed by Kaplan-Meier curve following log-rank test and multivariable Cox regression analysis. Results In total, 63 (87.5%) of patients with AF were dead and 147 (59.8%) of patients with SR were dead during the follow-up period. The best cut-off was 80 bpm, with a sensitivity of 62% and specificity of 66%. HR ≤ 80 bpm in SR but not in AF was associated with better outcome as compared with HR > 80 bpm (Chi-Square = 26.55, Log rank P < 0.001). In SR subgroup, the hazard ratios of HR ≤ 80 bpm were 0.51(95% CI 0.37-0.70, P < 0.001) adjusted for age, 0.46 (95%CI 0.33-0.63, P < 0.001) adjusted for gender, 0.62 (95%CI 0.42- 0.93, P = 0.020) adjusted for multivariables respectively. In AF subgroup, the hazard ratios of HR ≤ 80 bpm were 0.83(95% CI 0.49-1.38, P = 0.464) adjusted for age, 0.96 (95%CI 0.59-1.58, P = 0.882) adjusted for gender, 0.72(95% CI 0.41-1.26, P = 0.249) adjusted for multivariables respectively. Conclusion The current study demonstrates that heart rate is an independent prognostic predictor for all-cause mortality, and HR ≤ 80 bpm is associated with improved outcome in SR but not in AF in octogenarian patients with ACS. PMID:29255559

Effect of age and sex on efficacy and tolerability of β blockers in patients with heart failure with reduced ejection fraction: individual patient data meta-analysis.

PubMed

Kotecha, Dipak; Manzano, Luis; Krum, Henry; Rosano, Giuseppe; Holmes, Jane; Altman, Douglas G; Collins, Peter D; Packer, Milton; Wikstrand, John; Coats, Andrew J S; Cleland, John G F; Kirchhof, Paulus; von Lueder, Thomas G; Rigby, Alan S; Andersson, Bert; Lip, Gregory Y H; van Veldhuisen, Dirk J; Shibata, Marcelo C; Wedel, Hans; Böhm, Michael; Flather, Marcus D

2016-04-20

To determine the efficacy and tolerability of β blockers in a broad age range of women and men with heart failure with reduced ejection fraction (HFrEF) by pooling individual patient data from placebo controlled randomised trials. Prospectively designed meta-analysis of individual patient data from patients aged 40-85 in sinus rhythm at baseline, with left ventricular ejection fraction <0.45. 13,833 patients from 11 trials; median age 64; 24% women. The primary outcome was all cause mortality; the major secondary outcome was admission to hospital for heart failure. Analysis was by intention to treat with an adjusted one stage Cox proportional hazards model. Compared with placebo, β blockers were effective in reducing mortality across all ages: hazard ratios were 0.66 (95% confidence interval 0.53 to 0.83) for the first quarter of age distribution (median age 50); 0.71 (0.58 to 0.87) for the second quarter (median age 60); 0.65 (0.53 to 0.78) for the third quarter (median age 68); and 0.77 (0.64 to 0.92) for the fourth quarter (median age 75). There was no significant interaction when age was modelled continuously (P=0.1), and the absolute reduction in mortality was 4.3% over a median follow-up of 1.3 years (number needed to treat 23). Admission to hospital for heart failure was significantly reduced by β blockers, although this effect was attenuated at older ages (interaction P=0.05). There was no evidence of an interaction between treatment effect and sex in any age group. Drug discontinuation was similar regardless of treatment allocation, age, or sex (14.4% in those give β blockers, 15.6% in those receiving placebo). Irrespective of age or sex, patients with HFrEF in sinus rhythm should receive β blockers to reduce the risk of death and admission to hospital.Registration PROSPERO CRD42014010012; Clinicaltrials.gov NCT00832442. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Measurement and Data Transmission Validity of a Multi-Biosensor System for Real-Time Remote Exercise Monitoring Among Cardiac Patients.

PubMed

Rawstorn, Jonathan C; Gant, Nicholas; Warren, Ian; Doughty, Robert Neil; Lever, Nigel; Poppe, Katrina K; Maddison, Ralph

2015-03-20

Remote telemonitoring holds great potential to augment management of patients with coronary heart disease (CHD) and atrial fibrillation (AF) by enabling regular physiological monitoring during physical activity. Remote physiological monitoring may improve home and community exercise-based cardiac rehabilitation (exCR) programs and could improve assessment of the impact and management of pharmacological interventions for heart rate control in individuals with AF. Our aim was to evaluate the measurement validity and data transmission reliability of a remote telemonitoring system comprising a wireless multi-parameter physiological sensor, custom mobile app, and middleware platform, among individuals in sinus rhythm and AF. Participants in sinus rhythm and with AF undertook simulated daily activities, low, moderate, and/or high intensity exercise. Remote monitoring system heart rate and respiratory rate were compared to reference measures (12-lead ECG and indirect calorimeter). Wireless data transmission loss was calculated between the sensor, mobile app, and remote Internet server. Median heart rate (-0.30 to 1.10 b∙min -1 ) and respiratory rate (-1.25 to 0.39 br∙min -1 ) measurement biases were small, yet statistically significant (all P≤.003) due to the large number of observations. Measurement reliability was generally excellent (rho=.87-.97, all P<.001; intraclass correlation coefficient [ICC]=.94-.98, all P<.001; coefficient of variation [CV]=2.24-7.94%), although respiratory rate measurement reliability was poor among AF participants (rho=.43, P<.001; ICC=.55, P<.001; CV=16.61%). Data loss was minimal (<5%) when all system components were active; however, instability of the network hosting the remote data capture server resulted in data loss at the remote Internet server during some trials. System validity was sufficient for remote monitoring of heart and respiratory rates across a range of exercise intensities. Remote exercise monitoring has potential to augment current exCR and heart rate control management approaches by enabling the provision of individually tailored care to individuals outside traditional clinical environments. ©Jonathan C Rawstorn, Nicholas Gant, Ian Warren, Robert Neil Doughty, Nigel Lever, Katrina K Poppe, Ralph Maddison. Originally published in JMIR Rehabilitation and Assistive Technology (http://rehab.jmir.org), 20.03.2015.

Bitopic Sphingosine 1-Phosphate Receptor 3 (S1P3) Antagonist Rescue from Complete Heart Block: Pharmacological and Genetic Evidence for Direct S1P3 Regulation of Mouse Cardiac Conduction.

PubMed

Sanna, M Germana; Vincent, Kevin P; Repetto, Emanuela; Nguyen, Nhan; Brown, Steven J; Abgaryan, Lusine; Riley, Sean W; Leaf, Nora B; Cahalan, Stuart M; Kiosses, William B; Kohno, Yasushi; Brown, Joan Heller; McCulloch, Andrew D; Rosen, Hugh; Gonzalez-Cabrera, Pedro J

2016-01-01

The molecular pharmacology of the G protein-coupled receptors for sphingosine 1-phosphate (S1P) provides important insight into established and new therapeutic targets. A new, potent bitopic S1P3 antagonist, SPM-354, with in vivo activity, has been used, together with S1P3-knockin and S1P3-knockout mice to define the spatial and functional properties of S1P3 in regulating cardiac conduction. We show that S1P3 is a key direct regulator of cardiac rhythm both in vivo and in isolated perfused hearts. 2-Amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol in vivo and S1P in isolated hearts induced a spectrum of cardiac effects, ranging from sinus bradycardia to complete heart block, as measured by a surface electrocardiogram in anesthetized mice and in volume-conducted Langendorff preparations. The agonist effects on complete heart block are absent in S1P3-knockout mice and are reversed in wild-type mice with SPM-354, as characterized and described here. Homologous knockin of S1P3-mCherry is fully functional pharmacologically and is strongly expressed by immunohistochemistry confocal microscopy in Hyperpolarization Activated Cyclic Nucleotide Gated Potassium Channel 4 (HCN4)-positive atrioventricular node and His-Purkinje fibers, with relative less expression in the HCN4-positive sinoatrial node. In Langendorff studies, at constant pressure, SPM-354 restored sinus rhythm in S1P-induced complete heart block and fully reversed S1P-mediated bradycardia. S1P3 distribution and function in the mouse ventricular cardiac conduction system suggest a direct mechanism for heart block risk that should be further studied in humans. A richer understanding of receptor and ligand usage in the pacemaker cells of the cardiac system is likely to be useful in understanding ventricular conduction in health, disease, and pharmacology. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Effect of hypergravity on the circadian rhythms of white rats.

NASA Technical Reports Server (NTRS)

Lafferty, J. F.

1972-01-01

The effects of artificial gravity on the circadian rhythm of white rats was observed by comparing feeding activity at 1.0 and 1.75 g. The feeding cycle data were obtained by observing the number of feeding switch responses, as well as the amount of food obtained, as a function of time. One of the three subjects clearly established a free-running cycle with a period of 24.742 hr. During a 40-day exposure to the 1.75 g environment, the subjects maintained the same feeding cycle period which was established at 1.0 g. While the results of this study indicate that the activity rhythms of rats are insensitive to gravity levels between 1.0 and 1.75 g, the effects of gravity levels below 1.0 g are yet to be determined.

Circadian Rhythm Connections to Oxidative Stress: Implications for Human Health

PubMed Central

Wilking, Melissa; Ndiaye, Mary; Mukhtar, Hasan

2013-01-01

Abstract Significance: Oxygen and circadian rhythmicity are essential in a myriad of physiological processes to maintain homeostasis, from blood pressure and sleep/wake cycles, down to cellular signaling pathways that play critical roles in health and disease. If the human body or cells experience significant stress, their ability to regulate internal systems, including redox levels and circadian rhythms, may become impaired. At cellular as well as organismal levels, impairment in redox regulation and circadian rhythms may lead to a number of adverse effects, including the manifestation of a variety of diseases such as heart diseases, neurodegenerative conditions, and cancer. Recent Advances: Researchers have come to an understanding as to the basics of the circadian rhythm mechanism, as well as the importance of the numerous species of oxidative stress components. The effects of oxidative stress and dysregulated circadian rhythms have been a subject of intense investigations since they were first discovered, and recent investigations into the molecular mechanisms linking the two have started to elucidate the bases of their connection. Critical Issues: While much is known about the mechanics and importance of oxidative stress systems and circadian rhythms, the front where they interact has had very little research focused on it. This review discusses the idea that these two systems are together intricately involved in the healthy body, as well as in disease. Future Directions: We believe that for a more efficacious management of diseases that have both circadian rhythm and oxidative stress components in their pathogenesis, targeting both systems in tandem would be far more successful. Antioxid. Redox Signal. 19, 192–208 PMID:23198849

Leptin-sensitive neurons in the arcuate nuclei contribute to endogenous feeding rhythms

PubMed Central

Wiater, Michael F.; Oostrom, Marjolein T.; Smith, Bethany R.; Wang, Qing; Dinh, Thu T.; Roberts, Brandon L.; Jansen, Heiko T.; Ritter, Sue

2012-01-01

Neural sites that interact with the suprachiasmatic nuclei (SCN) to generate rhythms of unrestricted feeding remain unknown. We used the targeted toxin, leptin conjugated to saporin (Lep-SAP), to examine the importance of leptin receptor-B (LepR-B)-expressing neurons in the arcuate nucleus (Arc) for generation of circadian feeding rhythms. Rats given Arc Lep-SAP injections were initially hyperphagic and rapidly became obese (the “dynamic phase” of weight gain). During this phase, Lep-SAP rats were arrhythmic under 12:12-h light-dark (LD) conditions, consuming 59% of their total daily intake during the daytime, compared with 36% in blank-SAP (B-SAP) controls. Lep-SAP rats were also arrhythmic in continuous dark (DD), while significant circadian feeding rhythms were detected in all B-SAP controls. Approximately 8 wk after injection, Lep-SAP rats remained obese but transitioned into a “static phase” of weight gain marked by attenuation of their hyperphagia and rate of weight gain. In this phase, Arc Lep-SAP rats exhibited circadian feeding rhythms under LD conditions, but were arrhythmic in continuous light (LL) and DD. Lep-SAP injections into the ventromedial hypothalamic nucleus did not cause hyperphagia, obesity, or arrhythmic feeding in either LD or DD. Electrolytic lesion of the SCN produced feeding arrhythmia in DD but not hyperphagia or obesity. Results suggest that both Arc Lep-SAP neurons and SCN are required for generation of feeding rhythms entrained to photic cues, while also revealing an essential role for the Arc in maintaining circadian rhythms of ad libitum feeding independent of light entrainment. PMID:22492818

Surgical management of anomalous pulmonary venous connection to the superior vena cava - early results

PubMed Central

Chandra, Dinesh; Gupta, Anubhav; Nath, Ranjit K.; kazmi, Aamir; Grover, Vijay; Gupta, Vijay K.

2013-01-01

Background The anatomical variability in patients with anomalous pulmonary venous connection to superior vena cava presents a surgical challenge. The problem is further compounded by the common occurrence of postoperative complications like arrhythmias and obstruction of the superior vena cava or pulmonary veins. We present our experience of managing this subset using the two patch and Warden's techniques. Patients and methods Between June 2011 and September 2012, 7 patients with APVC to the SVC were operated in our institute. After delineating the anatomy, five of them had a two patch repair and two were managed with Warden's technique. Results There was no in-hospital mortality or early mortality over a mean follow-up of 9.66 ± 3.88 months (range 6–15 months). All the patients on follow-up had unobstructed pulmonary venous and SVC drainage on echocardiography and all of them were in normal sinus rhythm. Conclusions Anomalous pulmonary venous connection to superior vena cava is a challenging subset of patients in whom the surgical management needs to be individualized. The detailed anatomy must be delineated using echocardiography with or without CT angiography before deciding the surgical plan. This entity can be repaired with excellent immediate and early results. However, these patients must be closely followed up for complications like systemic and pulmonary venous obstruction and sinus node dysfunction. PMID:24206880

Starling resistors, autoregulation of cerebral perfusion and the pathogenesis of idiopathic intracranial hypertension.

PubMed

DE Simone, Roberto; Ranieri, Angelo; Bonavita, Vincenzo

2017-03-01

Two critical functions for the control of intracranial fluids dynamics are carried on the venous side of the perfusion circuit: the first is the avoidance of cortical veins collapse during the physiological increases of cerebrospinal fluid (CSF) pressure in which they are immersed. The second, is the generation of an abrupt venous pressure drop at the confluence of the cortical veins with the dural sinuses that is required to allow a CSF outflow rate balanced with its production. There is evidence that both of these effects are ensured by a Starling resistor mechanism (a fluid dynamic construct that governs the flow in collapsible tubes exposed to variable external pressure) acting at the confluence of cortical veins in the dural sinus. This implies that, in normal circumstances of perfusion balance, a certain degree of venous collapse physiologically occurs at the distal end of the cortical vein. This is passively modulated by the transmural pressure of the venous wall (i.e. the difference between internal blood pressure and external CSF pressure). The mechanism provides that the blood pressure of the cortical vein upstream the collapsed segment is dynamically maintained a few mmHg higher than the CSF pressure, so as to prevent their collapse during the large physiological fluctuations of the intracranial pressure. Moreover, the partial collapse of the vein confluence also generates a sharp pressure drop of the blood entering into the sinus. The CSF is drained in dural sinus through arachnoid villi proportionally to its pressure gradient with the sinus blood. The venous pressure drop between cortical veins and dural sinus is therefore needed to ensure that the CSF can leave the cranio-spinal space with the same speed with which it is produced, without having to reach a too high pressure, which would compress the cortical veins. Notably, the mechanism requires that the walls of the dural sinuses are rigid enough to avoid the collapse under the external cerebrospinal fluid pressure, and predicts that in the presence of excessively flexible dural sinuses, the system admits a second point of balance between cerebral fluid pressure and dural sinus pressure, at higher values. The second balance state is due to the triggering of a self-limiting venous collapse feedback loop between the CSF pressure, that compresses the sinus, and the subsequent increase of the dural sinus pressure, that further raises the intracranial pressure. The loop may stabilize only when the maximum stretching allowed by the venous wall is reached. Then, a new relatively stable and self-sustaining balance state is achieved, at the price of a higher CSF and dural sinus pressure values. We propose that this model is crucially involved in Idiopatic Intracranial Hypertension pathogenesis with and without papilledema, a condition that could be described as a pathological new balance state, relatively stable, between intracranial and dural venous pressure, at higher absolute values.

Second diastolic pulmonary venous flow and isolated late diastolic mitral valve regurgitation in first-degree atrioventricular block.

PubMed

Leibundgut, Gregor; Bernheim, Alain M

2010-04-01

The authors report the case of a 77-year-old male patient with sinus rhythm and a first-degree atrioventricular (AV) block who was referred for echocardiographic follow-up 18 years after aortic valve replacement. Left ventricular systolic function as well as the function of the aortic prosthesis was normal. Systolic mitral regurgitation (MR) was virtually absent, but isolated late diastolic MR was detected by colour Doppler imaging. Coincidental to the occurrence of diastolic MR, a second late diastolic forward flow in the pulmonary veins was observed. Therefore, during the prolonged left atrial relaxation caused by first-degree AV block, the left atrial pressure drops below the pressure in both adjacent chambers in late diastole, resulting in both late diastolic MR and a second diastolic pulmonary venous forward flow.

Rare case of left-dominant arrhythmogenic right ventricular cardiomyopathy with dramatic reverse remodeling after cardiac resynchronization as an adjunct to pharmacological therapy.

PubMed

Hsiao, Chih-Chung; Kuo, Jen-Yuan; Yun, Chun-Ho; Hung, Chung-Lieh; Tsai, Cheng-Ho; Yeh, Hung-I

2012-01-01

A 57-year-old man presented with near syncope and hemodynamic compromise after exercise. A sustained ventricular tachycardia (VT) of right bundle-branch block morphology was evident upon examination at our emergency department. Baseline 12-lead electrocardiography revealed a sinus rhythm with a complete left bundle-branch block after successful cardioversion of the VT. Coronary angiography revealed patent coronary arteries, whereas left ventriculography demonstrated impaired systolic function, accompanied by a peculiar basal lateral aneurysm. Both echocardiography and magnetic resonance imaging were consistent with a diagnosis of left-dominant arrhythmogenic right ventricular cardiomyopathy. Four months later, substantial ventricular reverse remodeling and clinical improvements were observed after cardiac resynchronization therapy with a defibrillator, as an adjunct to conventional pharmacological therapy. Copyright © 2012 Elsevier Inc. All rights reserved.

Atypical patterns of cardiac involvement in Fabry disease.

PubMed

Coughlan, J J; Elkholy, K; O'Brien, J; Kiernan, T

2016-03-17

A 58-year-old woman was referred to our cardiology service with chest pain, exertional dyspnoea and palpitations on a background of known Fabry disease diagnosed with genetic testing in 1994. ECG showed sinus rhythm, shortened PR interval, widespread t wave inversion, q waves in the lateral leads and left ventricular hypertrophy (LVH). Coronary angiogram showed only mild atheroma. Transthoracic echocardiogram showed anterolateral LVH and reduced left ventricular cavity size in keeping with Fabry cardiomyopathy. Cardiac MRI demonstrated asymmetric hypertrophy with evidence of diffuse myocardial fibrosis in the maximally hypertrophied segments from base to apex with late gadolinium enhancement in the anterior and anteroseptal walls. This was quite an atypical appearance for Fabry cardiomyopathy. This case highlights the heterogeneity of patterns of cardiac involvement that may be associated with this rare X-linked lysosomal disorder. 2016 BMJ Publishing Group Ltd.

Effects of novel oral anticoagulants on left atrial and left atrial appendage thrombi: an appraisal.

PubMed

Marsico, Fabio; Cecere, Milena; Parente, Antonio; Paolillo, Stefania; de Martino, Fabiana; Dellegrottaglie, Santo; Trimarco, Bruno; Perrone Filardi, Pasquale

2017-02-01

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and predisposes to an increased risk of thromboembolic events. Patients affected by AF exhibit an increased risk of stroke compared with those in sinus rhythm, with the most common location of thrombi in the left atrial appendage. Until 2009, warfarin and other vitamin K antagonists were the only class of oral anticoagulants available. More recently, dabigatran, rivaroxaban, apixaban, and edoxaban have been approved by regulatory authorities for prevention of stroke in patients with non-valvular AF. Few data are available about the efficacy of novel oral anticoagulants for the treatment of left atrial and left atrial appendage thrombosis. Aim of this review is to summarize available evidence regarding the effectiveness of novel oral anticoagulants on left atrial appendage thrombosis.

Acute exposure to 2G phase shifts the rat circadian timing system

NASA Technical Reports Server (NTRS)

Hoban-Higgins, T. M.; Murakami, D. M.; Tandon, T.; Fuller, C. A.

1995-01-01

The circadian timing system (CTS) provides internal and external temporal coordination of an animal's physiology and behavior. In mammals, the generation and coordination of these circadian rhythms is controlled by a neural pacemaker, the suprachiasmatic nucleus (SCN), located within the hypothalamus. The pacemaker is synchronized to the 24 hour day by time cures (zeitgebers) such as the light/dark cycle. When an animal is exposed to an environment without time cues, the circadian rhythms maintain internal temporal coordination, but exhibit a 'free-running' condition in which the period length is determined by the internal pacemaker. Maintenance of internal and external temporal coordination are critical for normal physiological and psychological function in human and non-human primates. Exposure to altered gravitational environments has been shown to affect the amplitude, mean, and timing of circadian rhythms in species ranging from unicellular organisms to man. However, it has not been determined whether altered gravitational fields have a direct effect on the neural pacemaker, or affect peripheral parameters. In previous studies, the ability of a stimulus to phase shift circadian rhythms was used to determine whether a stimulus has a direct effect on the neural pacemaker. The present experiment was performed in order to determine whether acute exposure to a hyperdynamic field could phase shift circadian rhythms.

Exercise attenuates the metabolic effects of dim light at night.

PubMed

Fonken, Laura K; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

2014-01-30

Most organisms display circadian rhythms that coordinate complex physiological and behavioral processes to optimize energy acquisition, storage, and expenditure. Disruptions to the circadian system with environmental manipulations such as nighttime light exposure alter metabolic energy homeostasis. Exercise is known to strengthen circadian rhythms and to prevent weight gain. Therefore, we hypothesized providing mice a running wheel for voluntary exercise would buffer against the effects of light at night (LAN) on weight gain. Mice were maintained in either dark (LD) or dim (dLAN) nights and provided either a running wheel or a locked wheel. Mice exposed to dim, rather than dark, nights increased weight gain. Access to a functional running wheel prevented body mass gain in mice exposed to dLAN. Voluntary exercise appeared to limit weight gain independently of rescuing changes to the circadian system caused by dLAN; increases in daytime food intake induced by dLAN were not diminished by increased voluntary exercise. Furthermore, although all of the LD mice displayed a 24h rhythm in wheel running, nearly half (4 out of 9) of the dLAN mice did not display a dominant 24h rhythm in wheel running. These results indicate that voluntary exercise can prevent weight gain induced by dLAN without rescuing circadian rhythm disruptions. © 2013.

Effect of venous stenting on intracranial pressure in idiopathic intracranial hypertension.

PubMed

Matloob, Samir A; Toma, Ahmed K; Thompson, Simon D; Gan, Chee L; Robertson, Fergus; Thorne, Lewis; Watkins, Laurence D

2017-08-01

Idiopathic intracranial hypertension (IIH) is characterised by an increased intracranial pressure (ICP) in the absence of any central nervous system disease or structural abnormality and by normal CSF composition. Management becomes complicated once surgical intervention is required. Venous sinus stenosis has been suggested as a possible aetiology for IIH. Venous sinus stenting has emerged as a possible interventional option. Evidence for venous sinus stenting is based on elimination of the venous pressure gradient and clinical response. There have been no studies demonstrating the immediate effect of venous stenting on ICP. Patients with a potential or already known diagnosis of IIH were investigated according to departmental protocol. ICP monitoring was performed for 24 h. When high pressures were confirmed, CT venogram and catheter venography were performed to look for venous stenosis to demonstrate a pressure gradient. If positive, venous stenting would be performed and ICP monitoring would continue for a further 24 h after deployment of the venous stent. Ten patients underwent venous sinus stenting with concomitant ICP monitoring. Nine out of ten patients displayed an immediate reduction in their ICP that was maintained at 24 h. The average reduction in mean ICP and pulsatility was significant (p = 0.003). Six out of ten patients reported a symptomatic improvement within the first 2 weeks. Venous sinus stenting results in an immediate reduction in ICP. This physiological response to venous stenting has not previously been reported. Venous stenting could offer an alternative treatment option in correctly selected patients with IIH.

Pulmonary vein anatomy predicts freedom from atrial fibrillation using remote magnetic navigation for circumferential pulmonary vein ablation.

PubMed

Sohns, Christian; Sohns, Jan M; Bergau, Leonard; Sossalla, Samuel; Vollmann, Dirk; Lüthje, Lars; Staab, Wieland; Dorenkamp, Marc; Harrison, James L; O'Neill, Mark D; Lotz, Joachim; Zabel, Markus

2013-08-01

Multidetector computed tomography (MDCT) is frequently used to guide circumferential pulmonary vein ablation (PVA) for treatment of atrial fibrillation (AF) as it offers accurate visualization of the left atrial (LA) and pulmonary vein (PV) anatomy. This study aimed to identify if PV anatomy is associated with outcomes following PVA using remote magnetic navigation (RMN). We analysed data from 138 consecutive patients and 146 ablation procedures referred for PVA due to drug-refractory symptomatic AF (age 63 ± 11 years; 57% men; 69% paroxysmal AF). The RMN using the stereotaxis system and open-irrigated 3.5 mm ablation catheters was used in all procedures. Prior to PVA, all patients underwent electrocardiogram-gated 64-MDCT for assessment of LA dimensions, PV anatomy, and electro-anatomical image integration during the procedure. Regular PV anatomy was found in 68%, a common left PV ostium was detected in 26%, and variant anatomy of the right PVs was detected in 6%. After a mean follow-up of 337 ± 102 days, 63% of the patients maintained sinus rhythm after the initial ablation, and 83% when including repeat PVA. Although acutely successful PV isolation did not differ between anatomical subgroups (regular 3.5 ± 0.8 vs. variant 3.2 ± 1.3; P = 0.31), AF recurrence was significantly higher in patients with non-regular PV anatomy (P = 0.04, hazard ratio 1.72). Pulmonary vein anatomy did not influence complication rates. Pulmonary vein anatomy assessed by MDCT is a good predictor of AF recurrence after PVA using RMN.

Dronedarone: current evidence and future questions.

PubMed

Schafer, Jeremy A; Kjesbo, Nicole K; Gleason, Patrick P

2010-01-01

Atrial fibrillation (AF) is the most common sustained arrhythmia, affecting more than 2.2 million Americans. ACC/AHA/ESC guidelines for the management of patients with AF recommend amiodarone for maintaining sinus rhythm. Dronedarone is a derivative of amiodarone indicated for the treatment of AF. To provide an overview of dronedarone with a focus on the phase III trials and discuss unresolved questions of dronedarone. A literature search was conducted via the PubMed database using the keyword "dronedarone." Search was limited to human trials in english. The FDA website was searched for briefing documents and subcommittee meetings on dronedarone. Clinicaltrials.gov was searched with the keyword dronedarone for upcoming or unpublished clinical trials. Five phase III trials are available for dronedarone: ANDROMEDA, EURIDIS/ADONIS, ATHENA, ERATO, and DIONYSIS. EURIDIS/ADONIS and ATHENA demonstrated a reduction AF recurrence with dronedarone compared to placebo. The ANDROMEDA trial recruited patients with recent hospitalization for heart failure and was terminated due to an excess of deaths in the dronedarone group. The DIONYSIS trial was a comparative effectiveness trial that demonstrated less efficacy for dronedarone but improved tolerability compared to amiodarone. Dronedarone represents an option in the management of AF in select patients. Dronedarone is not appropriate in patients with recently decompensated heart failure or those treated with strong CYP3A4 inhibitors or medications prolonging the QT interval. Dronedarone appears to have improved tolerability at the expense of decreased efficacy when compared to amiodarone. Questions remain on the long-term safety, use in patients with heart failure, retreatment after dronedarone or amiodarone failure, and comparative efficacy with a rate control strategy.

The impact of cardiac rhythm on the mitral valve area and gradient in patients with mitral stenosis.

PubMed

Arı, Hasan; Arı, Selma; Karakuş, Alper; Camcı, Sencer; Doğanay, Kübra; Tütüncü, Ahmet; Melek, Mehmet; Bozat, Tahsin

2017-08-01

The aim of this study was to evaluate the effect of cardiac rhythm on the echocardiographic mitral valve area (MVA) and transmitral gradient calculation in relation to net atrioventricular compliance (Cn). Patients (n=22) with mild or moderate pure rheumatic mitral stenosis (MS) (MVA <2 cm2 and MVA >1 cm2) and atrial fibrillation (AF) were evaluated. All patients underwent transthoracic electrical DC cardioversion under amiodarone treatment. Nineteen of the 22 patients were successfully converted to sinus rhythm (SR). The patients were evaluated with transthoracic echocardiography before and two to three days after DC cardioversion. In order to deal with variable R-R intervals, the measurements were averaged on five to eight consecutive beats in AF. Cn was calculated with a previously validated equation [Cn (mL/mm Hg)=1.270 x MVA/E-wave downslope]. The Cn difference between AF and SR was calculated as follows: [(AF Cn-SR Cn)/AF Cn] x 100. The percentage gradient (mean or maximal) difference between AF and SR was calculated as follows: [AF gradient (mean or maximal) - SR gradient (mean or maximal)]/[AF gradient (mean or maximal)] x 100. The MVA was lower (MVA planimetric; 1.62±0.29 vs. 1.54±0.27; p=.003, MVA PHT; 1.66±0.30 vs. 1.59±0.26; p=0.01) but transmitral gradient (mean gradient; 6.49±2.51 vs. 8.89±3.52; p=0.001, maximal gradient: 16.94±5.11 vs. 18.57±4.54; p=0.01) and Cn values (5.37±0.77 vs. 6.26±0.64; p<0.001) were higher in the AF than SR. There was a significant correlation between Cn difference and transmitral gradient difference (mean and maximal) (Cn difference-mean gradient difference; r=0.46; p=0.05; Cn difference-maximal gradient difference; r=0.72; p=0.001). Cardiac rhythm has a significant impact on echocardiographic evaluation of MVA, transmitral gradient, and Cn in patients with MS.

[Regulation of pyloric rhythm by I(A) and I(h) in crayfish stomatogastric ganglion].

PubMed

Kuang, Guo-Hui; Liu, Yi-Hui; Ren, Wei

2012-06-25

The stomatogastric ganglion (STG) of shellfish includes 30 neurons and produces pyloric rhythms. It is the common model to study central pattern generator (CPG). Regulation of pyloric rhythms not only is related to the property of single neurons in STG but also depends on the connections and property of the whole neuronal network. It has been found that transient potassium current (I(A)) and hyperpolarization-activated cation current (I(h)) exist in certain types of neurons of STG. However, roles played by these two currents in maintaining and regulating the pyloric rhythms are unknown. In the present study, in vitro electrophysiological recordings were performed on crayfish STG to examine the role played by I(A) and I(h) in regulation of pyloric rhythm. 4AP (2 mmol/L), a specific inhibitor of I(A), caused a decrease in pyloric cycle (P < 0.01), an increase in PD (pyloric dilator) ratio, a decrease in PY (pyloric) ratio (P < 0.01) and delay of phases of LP and PY firing. ZD7288 (100 μmol/L), a specific inhibitor of I(h), caused a decrease in pyloric cycle (P < 0.01), an increase in PD ratio (P < 0.01), an increase in LP (lateral pyloric) ratio (P < 0.01), a decrease in PY ratio (P < 0.01) and delay of phases of LP and PY firing. These results indicate that I(A) and I(h) play important roles in regulating pyloric rhythms in crayfish STG.

Chronobiology and circadian rhythms establish a connection to diagnosis.

PubMed

Nydegger, Urs E; Escobar, Pedro Medina; Risch, Lorenz; Risch, Martin; Stanga, Zeno

2014-12-01

Circadian rhythms are synchronized by the light/dark (L/D) cycle over the 24-h day. A suprachiasmatic nucleus in the hypothalamus governs time keeping based on melanopsin messages from the retina in the eyes and transduces regulatory signals to tissues through an array of hormonal, metabolic and neural outputs. Currently, vague impressions on circadian regulation in health and disease are replaced by scientific facts: in addition to L/D cyling, oscillation is maintained by genetic (Clock, Bmal1, Csnk1, CHRONO, Cry, Per) programs, autonomous feedback loops, including melatonin activities, aerobic glycolysis intensity and lipid signalling, among others. Such a multifaceted influential system on circadian rhythm is bound to be fragile and genomic clock acitvities can become disrupted by epigenetic modifications or such environmental factors as mistimed sleep and feeding schedules albeit leaving the centrally driven melatonin-dependent pacemakter more or less unaffected.

Delayed Onset of Atrial Fibrillation and Ventricular Tachycardia after an Automobile Lightning Strike.

PubMed

Drigalla, Dorian; Essler, Shannon E; Stone, C Keith

2017-11-01

Lightning strike is a rare medical emergency. The primary cause of death in lightning strike victims is immediate cardiac arrest. The mortality rate from lightning exposure can be as high as 30%, with up to 70% of patients left with significant morbidity. An 86-year-old male was struck by lightning while driving his vehicle and crashed. On initial emergency medical services evaluation, he was asymptomatic with normal vital signs. During his transport, he lost consciousness several times and was found to be in atrial fibrillation with intermittent runs of ventricular tachycardia during the unconscious periods. In the emergency department, atrial fibrillation persisted and he experienced additional episodes of ventricular tachycardia. He was treated with i.v. amiodarone and admitted to cardiovascular intensive care unit, where he converted to a normal sinus rhythm on the amiodarone drip. He was discharged home without rhythm-control medications and did not have further episodes of dysrhythmias on follow-up visits. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Lightning strikes are one of the most common injuries suffered from natural phenomenon, and short-term mortality ordinarily depends on the cardiac effects. This case demonstrates that the cardiac effects can be multiple, delayed, and recurrent, which compels the emergency physician to be vigilant in the initial evaluation and ongoing observation of patients with lightning injuries. Copyright © 2017 Elsevier Inc. All rights reserved.

Cetamolol: a new cardioselective beta-adrenoceptor blocking agent without membrane-stabilizing activity.

PubMed

Beaulieu, G; Jaramillo, J; Cummings, J R

1984-03-01

Cetamolol, a new beta-adrenoceptor blocker with partial agonist activity and cardioselectivity, was studied in vivo to determine its membrane-stabilizing effects. Comparisons were carried out with atenolol, pindolol, practolol, propranolol, timolol, dexpropranolol, lidocaine, and procaine. The following results indicated that cetamolol lacked membrane-stabilizing activity: (i) failure to cause local anesthesia on the rabbit cornea and motor nerve of the rat tail; (ii) ineffectiveness in reversing ventricular arrhythmias induced by coronary artery litigation in dogs; (iii) failure to reduce cardiac automaticity in catecholamine-depleted dogs as determined by the rate of a subatrial rhythm during ventricular (vagal) escape; and (iv) lack of a significant increase in atrioventricular conduction time in vagotomized or atropinized dogs in contrast to the effect in normal dogs indicating a reflex effect of cetamolol. Other results include a restoration of sinus rhythm in dogs with ventricular tachycardia induced by ouabain, and a dose-related decline in the force of cardiac contraction in anesthetized dogs at doses from 3 to 15 mg/kg, which occurred after an initial increase in force owing to intrinsic sympathomimetic activity. Although the mechanisms for the latter two effects are not clear at this time, explanations other than membrane-stabilizing activity have been considered in view of the other findings. It is concluded that cetamolol lacks membrane-stabilizing activity even at inordinately high doses.

Electrocardiography in two subspecies of manatee (Trichechus manatus latirostris and Trichechus manatus manatus)

USGS Publications Warehouse

Siegal-Willott, J.; Estrada, A.; Bonde, R.K.; Wong, A.; Estrada, D.J.; Harr, K.

2006-01-01

Electrocardiographic (ECG) measurements were recorded in two subspecies of awake, apparently healthy, wild manatees (Trichechus manatus latirostris and T. m. manatus) undergoing routine field examinations in Florida and Belize. Six unsedated juveniles (dependent and independent calves) and 6 adults were restrained in ventral recumbency for ECG measurements. Six lead ECGs were recorded for all manatees and the following parameters were determined: heart rate and rhythm; P, QRS, and T wave morphology, amplitude, and duration; and mean electrical axis (MEA). Statistical differences using a t-test for equality of means were determined. No statistical difference was seen based on sex or subspecies of manatees in the above measured criteria. Statistical differences existed in heart rate (P = 0.047), P wave duration (P = 0.019), PR interval (P = 0.025), and MEA (P = 0.021) between adult manatees and calves. Our findings revealed normal sinus rhythms, no detectable arrhythmias, prolonged PR and QT intervals, prolonged P wave duration, and small R wave amplitude as compared with cetacea and other marine mammals. This paper documents the techniques for and baseline recordings of ECGs in juvenile and adult free-living manatees. It also demonstrates that continual assessment of cardiac electrical activity in the awake manatee can be completed and can be used to aid veterinarians and biologists in routine health assessment, during procedures, and in detecting the presence of cardiac disease or dysfunction.

Electrocardiography in two subspecies of manatee (Trichechus manatus latirostris and T. m. manatus).

PubMed

Siegal-Willott, Jessica; Estrada, Amara; Bonde, Robert; Wong, Arthur; Estrada, Daniel J; Harr, Kendal

2006-12-01

Electrocardiographic (ECG) measurements were recorded in two subspecies of awake, apparently healthy, wild manatees (Trichechus manatus latirostris and T. m. manatus) undergoing routine field examinations in Florida and Belize. Six unsedated juveniles (dependent and independent calves) and 6 adults were restrained in ventral recumbency for ECG measurements. Six lead ECGs were recorded for all manatees and the following parameters were determined: heart rate and rhythm; P, QRS, and T wave morphology, amplitude, and duration; and mean electrical axis (MEA). Statistical differences using a t-test for equality of means were determined. No statistical difference was seen based on sex or subspecies of manatees in the above measured criteria. Statistical differences existed in heart rate (P = 0.047), P wave duration (P = 0.019), PR interval (P = 0.025), and MEA (P = 0.021) between adult manatees and calves. Our findings revealed normal sinus rhythms, no detectable arrhythmias, prolonged PR and QT intervals, prolonged P wave duration, and small R wave amplitude as compared with cetacea and other marine mammals. This paper documents the techniques for and baseline recordings of ECGs in juvenile and adult free-living manatees. It also demonstrates that continual assessment of cardiac electrical activity in the awake manatee can be completed and can be used to aid veterinarians and biologists in routine health assessment, during procedures, and in detecting the presence of cardiac disease or dysfunction.

Atrial flutter with 1:1 conduction in undiagnosed Wolff-Parkinson-White syndrome.

PubMed

Nelson, Jessie G; Zhu, Dennis W

2014-05-01

Atrial flutter with 1:1 atrioventricular conduction via an accessory pathway is an uncommon presentation of Wolff-Parkinson-White syndrome not previously reported in the emergency medicine literature. Wolff-Parkinson-White syndrome, a form of ventricular preexcitation sometimes initially seen and diagnosed in the emergency department (ED), can present with varied tachydysrhythmias for which certain treatments are contraindicated. For instance, atrial fibrillation with preexcited conduction needs specific consideration of medication choice to avoid potential degeneration into ventricular fibrillation. We describe an adult female presenting with a very rapid, regular wide complex tachycardia successfully cardioverted in the ED followed by a normal electrocardiogram (ECG). Electrophysiology study confirmed atrial flutter with 1:1 conduction and revealed an accessory pathway consistent with Wolff-Parkinson-White syndrome, despite lack of ECG findings of preexcitation during sinus rhythm. Why should an emergency physician be aware of this? Ventricular tachycardia must be the first consideration in patients with regular wide complex tachycardia. However, clinicians should consider atrial flutter with 1:1 conduction related to an accessory pathway when treating patients with the triad of very rapid rate (>250 beats/min), wide QRS complex, and regular rhythm, especially when considering pharmacologic treatment. Emergency physicians also should be aware of electrocardiographically concealed accessory pathways, and that lack of delta waves does not rule out preexcitation syndromes such as Wolff-Parkinson-White syndrome. Copyright © 2014 Elsevier Inc. All rights reserved.

Earth--moon evolution: implications for the mechanism of the biological clock?

PubMed

Shweiki, D

2001-04-01

The geophysical characteristics of the planet Earth dictate the physiological traits of living organisms. Changes in the geophysical conditions over the course of geological time are responsible for major evolutionary changes in life emergence and evolvement. Calendar day length is one of earth's geophysical characteristics which is under a constant, if extremely small, progressive change. This enforces an adjustment of circadian rhythmicity throughout geological time. The calendar day has extended approximately 9 hours in the last 3.5 billion years. Two mechanisms for circadian-rhythm adjustment are suggested: a directional selection mechanism -- an endogenous -- oriented explanation regarding a genetic drift in the population's endogenous oscillation toward a lengthened daily cycle; and an exogenous calibration mechanism - a hypothesis on the existence of a geophysical responsive element which senses a geophysical stimuli and calibrates the inner cellular oscillation in accordance with the length of the calendar day. A distinguishing experiment between the two explanations is suggested and discussed. Circadian rhythm mechanism and the evolution of circadian rhythmicity are tightly connected. Circadian rhythms' evolutionary theories are discussed in light of their contribution to our understanding of the selective pressures being applied throughout geological time and of how, once the clock has been established, it maintains an ongoing adjustment to a continuous change in the length of day.I argue that the exogenous calibration mechanism combines with the endosymbiont coordination theory, together, present an explanation to the path by which the calendar day adjustment was acquired and maintained. This hypothesis suggests a role for gravity cyclic force and for cytoskeleton's components in calendar day adjustment mechanism and circadian rhythm entrainment. Copyright 2001 Harcourt Publishers Ltd.

Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).

PubMed

Singer, Daniel E; Albers, Gregory W; Dalen, James E; Fang, Margaret C; Go, Alan S; Halperin, Jonathan L; Lip, Gregory Y H; Manning, Warren J

2008-06-01

This chapter about antithrombotic therapy in atrial fibrillation (AF) is part of the American College of Chest Physicians Evidence-Based Guidelines Clinical Practice Guidelines (8th Edition). Grade 1 recommendations indicate that most patients would make the same choice and Grade 2 suggests that individual patient's values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2008; 133[suppl]:123S-131S). Among the key recommendations in this chapter are the following (all vitamin K antagonist [VKA] recommendations have a target international normalized ratio [INR] of 2.5; range 2.0-3.0, unless otherwise noted). In patients with AF, including those with paroxysmal AF, who have had a prior ischemic stroke, transient ischemic attack (TIA), or systemic embolism, we recommend long-term anticoagulation with an oral VKA, such as warfarin, because of the high risk of future ischemic stroke faced by this set of patients (Grade 1A). In patients with AF, including those with paroxysmal AF, who have two or more of the risk factors for future ischemic stroke listed immediately below, we recommend long-term anticoagulation with an oral VKA (Grade 1A). Two or more of the following risk factors apply: age >75 years, history of hypertension, diabetes mellitus, moderately or severely impaired left ventricular systolic function and/or heart failure. In patients with AF, including those with paroxysmal AF, with only one of the risk factors listed immediately above, we recommend long-term antithrombotic therapy (Grade 1A), either as anticoagulation with an oral VKA, such as warfarin (Grade 1A), or as aspirin, at a dose of 75-325 mg/d (Grade 1B). In these patients at intermediate risk of ischemic stroke we suggest a VKA rather than aspirin (Grade 2A). In patients with AF, including those with paroxysmal AF, age < or =75 years and with none of the other risk factors listed above, we recommend long-term aspirin therapy at a dose of 75-325 mg/d (Grade 1B), because of their low risk of ischemic stroke. For patients with atrial flutter, we recommend that antithrombotic therapy decisions follow the same risk-based recommendations as for AF (Grade 1C). For patients with AF and mitral stenosis, we recommend long-term anticoagulation with an oral VKA (Grade 1B). For patients with AF and prosthetic heart valves we recommend long-term anticoagulation with an oral VKA at an intensity appropriate for the specific type of prosthesis (Grade 1B). See CHEST 2008; 133(suppl):593S-629S. For patients with AF of > or =48 h or of unknown duration for whom pharmacologic or electrical cardioversion is planned, we recommend anticoagulation with an oral VKA, such as warfarin, for 3 weeks before elective cardioversion and for at least 4 weeks after sinus rhythm has been maintained (Grade 1C). For patients with AF of > or = 48 h or of unknown duration undergoing pharmacological or electrical cardioversion, we also recommend either immediate anticoagulation with unfractionated IV heparin, or low-molecular-weight heparin (LMWH), or at least 5 days of warfarin by the time of cardioversion (achieving an INR of 2.0-3.0) as well as a screening multiplane transesophageal echocardiography (TEE). If no thrombus is seen, cardioversion is successful, and sinus rhythm is maintained, we recommend anticoagulation for at least 4 weeks. If a thrombus is seen on TEE, then cardioversion should be postponed and anticoagulation should be continued indefinitely. We recommend obtaining a repeat TEE before attempting later cardioversion (Grade 1B addressing the equivalence of TEE-guided vs non-TEE-guided cardioversion). For patients with AF of known duration <48 h, we suggest cardioversion without prolonged anticoagulation (Grade 2C). However, in patients without contraindications to anticoagulation, we suggest beginning IV heparin or LMWH at presentation (Grade 2C).

Contribution of activity to the circadian rhythm in excretion of magnesium and calcium.

DOT National Transportation Integrated Search

1968-03-01

Eight subjects were maintained on a standard dietary regimen ingested every four hours for 120 hours. Measurements of the magnesium and calcium excretion in these subjects revealed a circadian periodicity with maximal levels of excretion for both ion...

The effects of feedback lighting on the circadian drinking rhythm in the diurnal new world primate Saimiri sciureus

NASA Technical Reports Server (NTRS)

Ferraro, J. S.; Sulzman, F. M.

1988-01-01

Feedback lighting provides illumination primarily during the subjective night (i.e., the photosensitive portion of the circadian cycle) in response to a given behavior. This technique has previously been used to test the nonparametric model of entrainment in nocturnal rodents. In three species (Rattus norvegicus, Mesocricetus auratus, and Mus musculus), the free-running period of the locomotor activity rhythm was similar whether the animals were exposed to continuous light or discrete light pulses occurring essentially only during the subjective night (i.e., feedback lighting). In the current experiments, feedback lighting was presented to squirrel monkeys so that light fell predominantly during the subjective night. Feedback lighting was linked to the drinking behavior in this diurnal primate so that when the animal drank, the lights went out. Despite the seemingly adverse predicament, the monkeys maintained regular circadian drinking rhythms. Furthermore, just as the period of the free-running activity rhythms of nocturnal rodents exposed to continuous light or feedback lighting were similar, the period of the drinking rhythms of the squirrel monkeys in continuous light and feedback lighting were comparable (25.6 +/- 0.1 and 25.9 +/- 0.1 hours, respectively), despite a substantial decrease in the total amount of light exposure associated with feedback lighting. The free-running period of monkeys exposed to continuous dark (24.5 +/- 0.1 hours) was significantly shorter than either of the two lighting conditions (P < 0.001). The results presented for the drinking rhythm were confirmed by examination of the temperature and activity rhythms. Therefore, discrete light pulses given predominately during the subjective night are capable of simulating the effects of continuous light on the free-running period of the circadian rhythms of a diurnal primate. The response of squirrel monkeys to feedback lighting thus lends further support for the model and suggests that the major entrainment mechanisms are similar in nocturnal rodents and diurnal primates.

Changes in the sleep-wake rhythm, sleep quality, mood, and quality of life of patients receiving treatment for lung cancer: A longitudinal study.

PubMed

Chang, Wen-Pei; Lin, Chia-Chin

2017-01-01

Studies on the diurnal sleep-wake rhythm of patients with lung cancer have mostly examined patients cross-sectionally, whereas the effects of lung cancer treatment over time have rarely been considered. Through long-term longitudinal tracking of patients with lung cancer, this study examined changes in their sleep-wake rhythm, sleep quality, anxiety, depressive symptoms, fatigue and quality of life (QoL) at various treatment stages. In addition, factors affecting their QoL were explored. Hierarchical linear modeling was adopted to analyze a convenience sample of 82 patients with lung cancer. The changes in their sleep-wake rhythm, sleep, mood (anxiety, depressive symptoms and fatigue) and QoL were observed at five time points: prior to treatment and at weeks 6, 12, 24 and 48 after the start of the treatment. The effects of sex, age, cancer stage, treatment type, comorbidities and time were controlled to determine the predictors of patients' QoL. The results showed that patients' sleep-wake rhythms were poor before treatments. Compared with baseline, the sleep-wake rhythms of the patients significantly improved at week 48, and anxiety significantly improved at weeks 6, 12, 24 and 48. By contrast, their fatigue became exacerbated at weeks 8 and 48. Moreover, QoL improved significantly from week 6 until the end of the treatment period. QoL was negatively affected by poor sleep quality (β = -0.69, p = 0.00) and depressive symptoms (β = -2.59, p < 0.001) and positively affected by regular sleep-wake rhythms (β = 0.23, p = 0.001). Therefore, clinical health-care professionals should focus more attention to the fatigue levels of patients with lung cancer before, during and after treatment. Health-care professionals may also need to provide such patients with health education regarding sleep hygiene and with emotional support to assist them in maintaining regular sleep-wake rhythms in order to improve their QoL.

Acute dim light at night increases body mass, alters metabolism, and shifts core body temperature circadian rhythms.

PubMed

Borniger, Jeremy C; Maurya, Santosh K; Periasamy, Muthu; Nelson, Randy J

2014-10-01

The circadian system is primarily entrained by the ambient light environment and is fundamentally linked to metabolism. Mounting evidence suggests a causal relationship among aberrant light exposure, shift work, and metabolic disease. Previous research has demonstrated deleterious metabolic phenotypes elicited by chronic (>4 weeks) exposure to dim light at night (DLAN) (∼ 5 lux). However, the metabolic effects of short-term (<2 weeks) exposure to DLAN are unspecified. We hypothesized that metabolic alterations would arise in response to just 2 weeks of DLAN. Specifically, we predicted that mice exposed to dim light would gain more body mass, alter whole body metabolism, and display altered body temperature (Tb) and activity rhythms compared to mice maintained in dark nights. Our data largely support these predictions; DLAN mice gained significantly more mass, reduced whole body energy expenditure, increased carbohydrate over fat oxidation, and altered temperature circadian rhythms. Importantly, these alterations occurred despite similar activity locomotor levels (and rhythms) and total food intake between groups. Peripheral clocks are potently entrained by body temperature rhythms, and the deregulation of body temperature we observed may contribute to metabolic problems due to "internal desynchrony" between the central circadian oscillator and temperature sensitive peripheral clocks. We conclude that even relatively short-term exposure to low levels of nighttime light can influence metabolism to increase mass gain.

Marine biorhythms: bridging chronobiology and ecology.

PubMed

Bulla, Martin; Oudman, Thomas; Bijleveld, Allert I; Piersma, Theunis; Kyriacou, Charalambos P

2017-11-19

Marine organisms adapt to complex temporal environments that include daily, tidal, semi-lunar, lunar and seasonal cycles. However, our understanding of marine biological rhythms and their underlying molecular basis is mainly confined to a few model organisms in rather simplistic laboratory settings. Here, we use new empirical data and recent examples of marine biorhythms to highlight how field ecologists and laboratory chronobiologists can complement each other's efforts. First, with continuous tracking of intertidal shorebirds in the field, we reveal individual differences in tidal and circadian foraging rhythms. Second, we demonstrate that shorebird species that spend 8-10 months in tidal environments rarely maintain such tidal or circadian rhythms during breeding, likely because of other, more pertinent, temporally structured, local ecological pressures such as predation or social environment. Finally, we use examples of initial findings from invertebrates (arthropods and polychaete worms) that are being developed as model species to study the molecular bases of lunar-related rhythms. These examples indicate that canonical circadian clock genes (i.e. the homologous clock genes identified in many higher organisms) may not be involved in lunar/tidal phenotypes. Together, our results and the examples we describe emphasize that linking field and laboratory studies is likely to generate a better ecological appreciation of lunar-related rhythms in the wild.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'. © 2017 The Authors.

Maxillary sinus floor augmentation using a nano-crystalline hydroxyapatite silica gel: case series and 3-month preliminary histological results.

PubMed

Canullo, Luigi; Dellavia, Claudia; Heinemann, Friedhelm

2012-03-20

The aim of this case series is to histologically examine a new hydroxyapatite in sinus lift procedure after 3 months. Ten 2-stage sinus lifts were performed in 10 healthy patients having initial bone height of 1-2mm and bone width of 5mm, asking for a fixed implant-supported rehabilitation. After graft material augmentation, a rough-surfaced mini-implant was inserted to maintain stability of the sinus widow. A bioptical core containing a mini-implant was retrieved 3 months after maxillary sinus augmentation with NanoBone(®) and processed for undecalcified histology. From the histomorphometric analysis, NanoBone(®) residuals accounted for the 38.26% ± 8.07% of the bioptical volume, marrow spaces for the 29.23% ± 5.18% and bone for the 32.51% ± 4.96% (new bone: 20.64% ± 2.96%, native bone: 11.87% ± 3.27%). Well-mineralized regenerated bone with lamellar parallel-fibred structure and Haversian systems surrounded the residual NanoBone(®) particles. The measured bone-to-implant contact amounted to 26.02% ± 5.46%. No connective tissue was observed at the implant boundary surface. In conclusion, the tested material showed good histological outcomes also 3 months after surgery. In such critical conditions, the use of a rough-surfaced mini-implant showed BIC values supposed to be effective also in case of functional loading. Although longer follow-up and a wider patient size are needed, these preliminary results encourage further research on this biomaterial for implant load also under early stage and critical conditions. Copyright © 2011 Elsevier GmbH. All rights reserved.

[Acute dietary poisoning by white hellebore (Veratrum album L.). Clinical and analytical data. A propos of 5 cases].

PubMed

Garnier, R; Carlier, P; Hoffelt, J; Savidan, A

1985-01-01

Five cases of acute accidental poisoning with White Hellebore are reported. All cases occurred several minutes after the ingestion of home-made gentian wine. The clinical signs were nausea, vomiting, abdominal pain, hypotension and bradycardia. The initial ECG showed sinus bradycardia in 4 cases. In one patient, complete atrioventricular block with an ectopic atrial bradycardia and an intermittent idioventricular rhythm was recorded. Symptomatic treatment and/or atropine led to recovery within a few hours. These symptoms suggested poisoning with a veratrum alkaloid. The White Hellebore (Veratrum Album L.) and the Yellow Gentian (Gentiana Lutea L.) often grow side by side in the fields; it is easy to confuse the two plants before they flower if one is not a botanist. Each gentian wine was analysed by thin layer chromatography and chemical ionisation spectrometry. All the wines contained Veratrum alkaloids.

[Atrial fibrillation as a comorbidity of heart failure].

PubMed

Wachter, R

2018-05-01

Atrial fibrillation and heart failure are diseases that frequently occur together in patients, and the prevalence of the two diseases will continue to increase in the future. Unfortunately, they exacerbate each other: the prognosis of patients with atrial fibrillation is poorer if there is heart failure, and the prognosis of heart failure patients with atrial fibrillation is poorer than the prognosis of heart failure patients without atrial fibrillation. In the past, studies on drug stabilization of sinus rhythm with antiarrhythmic drugs were not able to show any influence on the prognosis of patients. In these patients, it seems to be better to treat the atrial fibrillation interventionally. The CASTLE-AF study has just shown for the first time that isolation of the pulmonary vein to treat atrial fibrillation in heart failure patients has positive effects: hospital admissions for heart failure decreased and the overall survival improved. Further studies have shown that quality of life improves and performance is increased.

Visualization of Heart Rate Variability of Long-Term Heart Transplant Patient by Transition Networks: A Case Report.

PubMed

Wdowczyk, Joanna; Makowiec, Danuta; Dorniak, Karolina; Gruchała, Marcin

2016-01-01

We present a heart transplant patient at his 17th year of uncomplicated follow-up. Within a frame of routine check out several tests were performed. With such a long and uneventful follow-up some degree of graft reinnervation could be anticipated. However, the patient's electrocardiogram and exercise parameters seemed largely inconclusive in this regard. The exercise heart rate dynamics were suggestive of only mild, if any parasympathetic reinnervation of the graft with persisting sympathetic activation. On the other hand, traditional heart rate variability (HRV) indices were inadequately high, due to erratic rhythm resulting from interference of the persisting recipient sinus node or non-conducted atrial parasystole. New tools, originated from network representation of time series, by visualization short-term dynamical patterns, provided a method to discern HRV increase due to reinnervation from other reasons.

Occult thyrotoxicosis: a correctable cause of idiopathic atrial fibrillation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forfar, J.C.; Miller, H.C.; Toft, A.D.

1979-07-01

Serum total thyroxine, triiodothyronine and thyrotropin response to thyrotropin-releasing hormone were measured in 75 consecutive patients presenting to a cardiology clinic with atrial fibrillation with no obvious cardiovascular cause. A lack of response of serum thyrotropin to thyrotropin-releasing hormone, indicative of thyrotoxicosis, was found in 10 patients (13%), not all whom had raised serum thyroid hormone levels. These 10 patients were predominantly male, had no clinical signs of thyrotoxicosis and a relative excess of nonpalpable autonomous thyroid nodules demonstrated with scintigraphy. Eight of the 10 patients had reversion to stable sinus rhythm after treatment with iodine-131 or carbimazole, either spontaneouslymore » or after direct current cardioversion. It would appear that clinically occult thyrotoxicosis can be identified consistently only with the thyrotropin-releasing hormone test and is the cause of idiopathic atrial fibrillation in a significant proportion of patients.« less

Cardioverter-defibrillator implantation in myeloma-associated cardiac amyloidosis

PubMed Central

Campanile, Alfonso; Sozzi, Fabiola B; Canetta, Ciro; Danzi, Gian Battista

2013-01-01

A 62-year-old woman with multiple myeloma and light-chain amyloidosis with significant heart involvement developed an in-hospital cardiac arrest. After cardiopulmonary resuscitation, a stable sinus rhythm without any cerebral damage was restored, and the patient was admitted to the coronary care unit. A cardioverter-defibrillator was implanted, and it successfully intervened in two sustained ventricular tachycardia episodes and one ventricular fibrillation episode, which were recorded during hospitalization. After achieving discrete cardiac compensation, the patient was transferred to the emergency medicine department where she underwent chemotherapy for multiple myeloma. The patient died 40 days after admission from refractory heart failure. In the literature, there are studies that describe the use of cardioverter-defibrillator implantation in cardiac amyloidosis; however, at present, there is no evidence of a beneficial effect on survival with the use of this intervention. A high index of suspicion for amyloid heart disease and early diagnosis are critical to improving outcomes. PMID:24294034

Cardioverter-defibrillator implantation in myeloma-associated cardiac amyloidosis.

PubMed

Campanile, Alfonso; Sozzi, Fabiola B; Canetta, Ciro; Danzi, Gian Battista

2013-01-01

A 62-year-old woman with multiple myeloma and light-chain amyloidosis with significant heart involvement developed an in-hospital cardiac arrest. After cardiopulmonary resuscitation, a stable sinus rhythm without any cerebral damage was restored, and the patient was admitted to the coronary care unit. A cardioverter-defibrillator was implanted, and it successfully intervened in two sustained ventricular tachycardia episodes and one ventricular fibrillation episode, which were recorded during hospitalization. After achieving discrete cardiac compensation, the patient was transferred to the emergency medicine department where she underwent chemotherapy for multiple myeloma. The patient died 40 days after admission from refractory heart failure. In the literature, there are studies that describe the use of cardioverter-defibrillator implantation in cardiac amyloidosis; however, at present, there is no evidence of a beneficial effect on survival with the use of this intervention. A high index of suspicion for amyloid heart disease and early diagnosis are critical to improving outcomes.

Decision-making interventions to stop the global atrial fibrillation-related stroke tsunami.

PubMed

Cerasuolo, Joshua O; Montero-Odasso, Manuel; Ibañez, Agustin; Doocy, Shannon; Lip, Gregory Yh; Sposato, Luciano A

2017-04-01

Atrial fibrillation affects 33.5 million people worldwide and its prevalence is expected to double by 2050 because of the aging population. Atrial fibrillation confers a 5-fold higher risk of ischemic stroke compared to sinus rhythm. We present our view of the role of shared medical decision-making to combat global underutilization of oral anticoagulation for stroke prevention in atrial fibrillation patients. Oral anticoagulation underuse is widespread as it is present within atrial fibrillation patients of all risk strata and in countries across all income levels. Reasons for oral anticoagulation underuse include but are probably not limited to poor risk stratification, over-interpretation of contraindications, and discordance between physician prescription preferences and actual administration. By comparing a catastrophic event to the consequences of atrial fibrillation related strokes, it may help physicians and patients understand the negative outcomes associated with oral anticoagulation under-utilization and the magnitude to which oral anticoagulations neutralize atrial fibrillation burden.

[Propofol anesthesia for a patient with progressive muscular dystrophy].

PubMed

Egi, Moritoki; Tokioka, Hiroaki; Chikai, Takashi; Fukushima, Tomihiro; Ishizu, Tomoko; Tanaka, Toshiaki; Kosogabe, Yoshinori

2002-02-01

We gave propofol anesthesia to a patient with limb-girdle type of progressive muscular dystrophy. A 42 year-old male was to have skin graft for third degree burn. His respiratory function test showed %VC of 73.6% and %FEV1.0 of 107.6%. Arterial blood gas data were within normal ranges. He was anesthetized with propofol, fentanyl, vecuronium and nitrous oxide. During position change, Wenckebach type of second degree AV block occurred. AV block returned to sinus rhythm easily by injection of ephedrine hydrochloride and atropine sulfate, and reduction of propofol infusion rate. There were no perioperative respiratory complications and no clinical manifestations of malignant hyperthermia. Propofol anesthesia is suitable for limb-girdle type of progressive muscular dystrophy, because of very little possibility of triggering malignant hyperthermia, rapid awaking, minimal residual effects of the respiratory system, and easiness in controlling anesthetic depth.

[Seronin syndrome and cardiac arrest caused by high-dose moclobemide (case report)].

PubMed

Cekmen, N; Badalov, P; Erdemli, O

2008-01-01

Serotonin syndrome is the syndrome resulting from brain tissue serotonin accumulation and accompanying by central nervous system dysfunction and circulatory collapse, which leads to a serious mortal danger to life. A female patient aged 31 years, diagnosed as having chronic psychosis in the history, was admitted to an intensive care unit in a critical state for having taking an increased moclobemide dose. The patient developed cardiac arrest and cardiopulmonary resuscitation (CPR) was initiated. A 15-minute CPR recovered sinus rhythm and pulse on the peripheral arteries of the limbs. When consciousness and respiration improved, the patient was weaned from resuscitation and extubated on the second day. On day 4, the patient was transferred from the intensive care unit to the department of psychiatry. The authors consider that patients with overdosage of antipsychotic agents at a risk for such serious complications, such as cardiac arrest, should be necessarily monitored in the intensive care unit.

[High-dose magnesium sulfate in the treatment of aconite poisoning].

PubMed

Clara, A; Rauch, S; Überbacher, C A; Felgenhauer, N; Drüge, G

2015-05-01

This article reports the case of a 62-year-old male patient who ingested the roots of Monkshood (Aconitum napellus) and white hellebore (Veratrum album) dissolved in alcohol with a suicidal intention and suffered cardiotoxic and neurotoxic symptoms. After contacting the Poison Information Centre ventricular arrhythmia was treated with high-dose magnesium sulphate as the only antiarrhythmic agent and subsequently a stable sinus rhythm could be established after approximately 3 h. Aconitum napellus is considered the most poisonous plant in Europe and it is found in gardens, the Alps and the Highlands. Poisoning is mainly caused by the alkaloid aconite that leads to persistent opening and activation of voltage-dependent sodium channels resulting in severe cardiac and neurological toxicity. As no specific antidote is known so far, poisoning is associated with a high mortality. The therapy with high-dose magnesium sulphate is based on in vitro and animal experiments as well as limited clinical case reports.

Electrocardiographic screening for emphysema: the frontal plane P axis.

PubMed

Baljepally, R; Spodick, D H

1999-03-01

Because the most characteristic and sensitive electrocardiographic (ECG) correlate of pulmonary emphysema in adults is verticalization of the frontal plane P-wave vector (P axis), we investigated its strength as a lone criterion to screen for obstructive pulmonary disease (OPD) in an adult hospital population. In all, 954 consecutive unselected ECGs were required to yield 100 with P axis > or = +70 degrees (unequivocally negative P in a VL during sinus rhythm) and pulmonary function tests. and 100 with P axis < or = +50 degrees (unequivocally positive P-aVL). Obstructive pulmonary disease by both pulmonary function test and clinical criteria was present in 89 of 100 patients with vertical P axes and 4 of 100 patients without OPD. The high sensitivity (89% for this series) and high specificity (96%) makes vertical P axis a useful screening criterion. Its at-a-glance simplicity makes it "user-friendly."

United in Prevention–Electrocardiographic Screening for Chronic Obstructive Pulmonary Disease

PubMed Central

Mazic, Sanja; Stajic, Zoran; Djelic, Marina; Zlatkovic-Svenda, Mirjana; Putnikovic, Biljana

2013-01-01

CONFLICT OF INTEREST: NONE DECLARED Introduction P-wave abnormalities on the resting electrocardiogram have been associated with cardiovascular or pulmonary disease. So far, “Gothic” P wave and verticalization of the frontal plane axis is related to lung disease, particularly obstructive lung disease. Aim We tested if inverted P wave in AVl as a lone criteria of P wave axis >70° could be screening tool for emphysema. Material and method 1095 routine electrocardiograms (ECGs) were reviewed which yielded 478 (82,1%) ECGs with vertical P-axis in sinus rhythm. Charts were reviewed for the diagnosis of COPD and emphysema based on medical history and pulmonary function tests. Conclusion Electrocardiogram is very effective screening tool not only in cardiovascular field but in chronic obstructive pulmonary disease. The verticality of the P axis is usually immediately apparent, making electrocardiogram rapid screening test for emphysema. PMID:24058253

Tension pneumothorax accompanied by type A aortic dissection.

PubMed

Hifumi, Toru; Kiriu, Nobuaki; Inoue, Junichi; Koido, Yuichi

2012-11-09

A 51-year-old man was brought to the emergency room because of a sudden onset of severe dysponea. On presentation, his blood pressure was 94/55 mm Hg. Oxygen saturation was 86% while he was receiving 10 l/min oxygen through a non-rebreather mask. On physical examination, no jugular venous distention was noted, but breath sounds over the left lung were diminished. A bedside chest radiograph showed left tension pneumothorax, for which urgent needle decompression followed by chest thoracostomy was performed. Ventricular tachycardia developed, but a biphasic shock at 120 J immediately restored normal sinus rhythm. His vital signs, however, did not improve. A CT scan of the chest showed type A aortic dissection with bullae in the upper lobe of the left lung. He had an emergency operation for distal aortic arch displacement and was discharged on the 37th day of hospitalisation.

Survival of a highly toxic dose of caffeine.

PubMed

Bioh, Gabriel; Gallagher, Mark M; Prasad, Usha

2013-02-08

A 27-year-old woman with a history of depression and previous overdose presented within 60 min of ingestion of 50 g of caffeine powder. Initially alert but hypotensive and tachycardic, the patient developed a broad complex tachycardia followed by a seizure and multiple ventricular fibrillation (VF) arrests. Following multiple defibrillations for VF, eight cycles of cardiopulmonary resuscitation and treatment with amiodarone, lidocaine, magnesium and potassium supplementation, the patient went to the intensive care unit (ICU). While there, the patient had further VF and required haemofiltration for a profound metabolic acidaemia with cardiac rhythm instability. She developed a postcardiac arrest systemic inflammatory response syndrome with episodes of acute pulmonary oedema, profound vasoplegia, hypothermia and coagulopathy. After 5 days in the ICU, the patient was stable enough to be transferred to the ward, with a persistent sinus tachycardia, and was discharged 3 days later with cardiology and psychiatry follow-up.

Pacemaker implantation after catheter ablation for atrial fibrillation.

PubMed

Deshmukh, Abhishek J; Yao, Xiaoxi; Schilz, Stephanie; Van Houten, Holly; Sangaralingham, Lindsey R; Asirvatham, Samuel J; Friedman, Paul A; Packer, Douglas L; Noseworthy, Peter A

2016-01-01

Sinus node dysfunction requiring pacemaker implantation is commonly associated with atrial fibrillation (AF), but may not be clinically apparent until restoration of sinus rhythm with ablation or cardioversion. We sought to determine frequency, time course, and predictors for pacemaker implantation after catheter ablation, and to compare the overall rates to a matched cardioversion cohort. We conducted a retrospective analysis using a large US commercial insurance database and identified 12,158 AF patients who underwent catheter ablation between January 1, 2005 and December 31, 2012. Over an average of 2.4 years of follow-up, 5.6 % of the patients underwent pacemaker implantation. Using the Cox proportional hazards models, we found that risk of risks of pacemaker implantation was associated with older age (50-64 and ≥65 versus <50 years), female gender, higher CHADS2 score (≥2 and 1 versus 0), higher Charlson index (≥2 versus 0-1), certain baseline comorbidities (conduction disorder, coronary atherosclerosis, and congestive heart failure), and the year of ablation. There was no significant difference in the risk of pacemaker implantation between ablation patients and propensity score (PS)-matched cardioversion groups (3.5 versus. 4.1 % at 1 year and 8.8 versus 8.3 % at 5 years). Overall, pacemaker implantation occurs in about 1/28 patients within 1 year of catheter ablation. The overall implantation rate decreased between 2005 and 2012. Furthermore, the risk after ablation is similar to cardioversion, suggesting that patients require pacing due to a common underlying electrophysiologic substrate, rather than the ablation itself.

Spanish Pacemaker Registry. Twelfth Official Report of the Spanish Society of Cardiology Working Group on Cardiac Pacing (2014).

PubMed

Cano Pérez, Óscar; Pombo Jiménez, Marta; Coma Samartín, Raúl

2015-12-01

This report describes the results of the analysis of pacemaker implant and replacement data submitted to the Spanish Pacemaker Registry in 2014, with special reference to pacing mode selection. The report is based on the processing of information provided by the European Pacemaker Patient Identification Card. Information was received from 117 hospitals, with a total of 12 358 cards, representing 34% of estimated activity. Use of conventional generators and resynchronization devices was 784 and 64.4 units per million population, respectively. The mean age of patients receiving an implant was 77.3 years. Men received 59% of implants and 56.4% of replacements. Most patients receiving generator implants and replacements were in the age range 80 to 89 years. Most endocardial leads used were bipolar, and 84.2% had an active fixation system. Pacing was in VVI/R mode despite being in sinus rhythm in 24.7% of patients with sick sinus syndrome and 24% of those with atrioventricular block. The use of pacemaker generators and resynchronization devices per million population continued to increase. Most implanted leads had active fixation and approximately 20% had magnetic resonance imaging protection. Age and sex directly influenced pacing mode selection, which could have been improved in more than 20% of cases. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Arrhythmias Following Comprehensive Stage II Surgical Palliation in Single Ventricle Patients.

PubMed

Wilhelm, Carolyn M; Paulus, Diane; Cua, Clifford L; Kertesz, Naomi J; Cheatham, John P; Galantowicz, Mark; Fernandez, Richard P

2016-03-01

Post-operative arrhythmias are common in pediatric patients following cardiac surgery. Following hybrid palliation in single ventricle patients, a comprehensive stage II palliation is performed. The incidence of arrhythmias in patients following comprehensive stage II palliation is unknown. The purpose of this study is to determine the incidence of arrhythmias following comprehensive stage II palliation. A single-center retrospective chart review was performed on all single ventricle patients undergoing a comprehensive stage II palliation from January 2010 to May 2014. Pre-operative, operative, and post-operative data were collected. A clinically significant arrhythmia was defined as an arrhythmia which led to cardiopulmonary resuscitation or required treatment with either pacing or antiarrhythmic medication. Statistical analysis was performed with Wilcoxon rank-sum test and Fisher's exact test with p < 0.05 significant. Forty-eight single ventricle patients were reviewed (32 hypoplastic left heart syndrome, 16 other single ventricle variants). Age at surgery was 185 ± 56 days. Cardiopulmonary bypass time was 259 ± 45 min. Average vasoactive-inotropic score was 5.97 ± 7.58. Six patients (12.5 %) had clinically significant arrhythmias: four sinus bradycardia, one 2:1 atrioventricular block, and one slow junctional rhythm. No tachyarrhythmias were documented for this patient population. Presence of arrhythmia was associated with elevated lactate (p = 0.04) and cardiac arrest (p = 0.002). Following comprehensive stage II palliation, single ventricle patients are at low risk for development of tachyarrhythmias. The most frequent arrhythmia seen in these patients was sinus bradycardia associated with respiratory compromise.

SPEAR Trial: Smartphone Pediatric ElectrocARdiogram Trial

PubMed Central

Nguyen, Hoang H.; Van Hare, George F.; Rudokas, Michael; Bowman, Tammy; Silva, Jennifer N. A.

2015-01-01

Objectives Smartphone-enabled ECG devices have the potential to improve patient care by enabling remote ECG assessment of patients with potential and diagnosed arrhythmias. This prospective study aimed to assess the usefulness of pediatric ECG tracings generated by the AliveCor device (Oklahoma City, OK) and to assess user satisfaction. Study Design Enrolled pediatric patients with documented paroxysmal arrhythmia used the AliveCor device over a yearlong study period. Pediatric electrophysiologists reviewed all transmitted ECG tracings. Patient completed surveys were analyzed to assess user satisfaction. Results 35 patients were enrolled with the following diagnoses: supraventricular tachycardia (SVT, 57%), atrial fibrillation (AF, 11%), ectopic atrial tachycardia (EAT, 6%), atrial tachycardia (AT, 3%), and ventricular tachycardia (VT, 23%). A total of 238 tracings were received from 20 patients, 96% of which were of diagnostic quality for sinus rhythm, sinus tachycardia, SVT, and AF. 126 patient satisfaction surveys (64% from parents) were completed. 98% of the survey responses indicated that it was easy to obtain tracings, 93% found it easy to transmit the tracings, 98% showed added comfort in managing arrhythmia by having the device, and 93% showed interest in continued use of the device after the study period ended. Conclusions Smartphone-enabled ECG devices can generate tracings of diagnostic quality in children. User satisfaction was extremely positive. Use of the device to manage certain patients with AF and SVT showcases the future role of remote ECGs in the successful outpatient management of arrhythmias in children by potentially reducing Emergency Department visits and healthcare costs. PMID:26295569

SRC-2 is an essential coactivator for orchastrating metabolism and circadian rhythm

USDA-ARS?s Scientific Manuscript database

Synchrony of the mammalian circadian clock is achieved by complex transcriptional and translational feedback loops centered on the BMAL1:CLOCK heterodimer. Modulation of circadian feedback loops is essential for maintaining rhythmicity, yet the role of transcriptional coactivators in driving BMAL1:C...

Impaired endothelial function in lone atrial fibrillation.

PubMed

Polovina, Marija; Potpara, Tatjana; Giga, Vojislav; Stepanović, Jelena; Ostojić, Miodrag

2013-10-01

Impaired endothelial function has been previously documented in patients with atrial fibrillation (AF) and underlying comorbidities or older patients with idiopathic AF. The aim of this study was to evaluate systemic endothelial function in younger AF patients (less than < 60 years old) with lone AF (that is, without associated cardiopulmonary comorbidities, including arterial hypertension), by comparing brachial artery flow-mediated dilation (FMD) in lone AF patients with FMD of healthy subjects in sinus rhythm. Two groups of participants were prospectively enrolled. The first group comprised of 38 AF patients (the mean age 45 +/- 11 years, 68% male) with persistent (> 7 days) lone AF. The second group comprised of 28 healthy controls in sinus rhythm (the mean age 43 +/- 13, 53% male), matched by age, gender and atherosclerotic risk factors. All the participants underwent physical examination, laboratory analysis [including determination of C-reactive protein (CRP)], standard echocardiography and exercise-stress testing. Brachial artery FMD and endothelium independent dilation (NMD) were assessed with a high-resolution ultrasound probe and arterial diameters taken from 5 consecutive cardiac cycles were averaged for each measurement to accommodate to beat-to-beat flow variations in AF. There were no differences between the 2 groups regarding age, gender and most clinical, laboratory and echocardiographic characteristics (all p > 0.05), apart from the increased heart rate (p = 0.018), body mass index (p = 0.027), CRP levels (p = 0.007) and left atrial anteroposterior dimension (p < 0.001) in AF patients. FMD of AF patients [median value 5.0%, interquartile range (IQR) 2.87%-7.50%] was significantly lower (p < 0.001) than FMD of healthy controls (median value 8.85%, IQR 5.80%-12.50%), whereas there were no differences in median NMD values (p > 0.05). In the multivariate analysis, the independent FMD determinants in our study population were the presence of AF, smoking and total cholesterol levels (all p < 0.001). In patients with AF, the strongest independent FMD determinant was arrhythmia duration (p < 0.001), followed by smoking (p = 0.013) and total cholesterol levels (p = 0.045). Our findings confirm that sustained AF is associated with systemic endothelial dysfunction even in relatively young patients with no cardiovascular disorders or risk factors. AF is an independent contributor to lower FMD and a prolonged arrhythmia duration may confer the risk for more profound endothelial damage.

Diagnostic Accuracy of a Novel Mobile Phone Application for the Detection and Monitoring of Atrial Fibrillation.

PubMed

Rozen, Guy; Vaid, Jeena; Hosseini, Seyed Mohammadreza; Kaadan, M Ihsan; Rafael, Allon; Roka, Attila; Poh, Yukkee C; Poh, Ming-Zher; Heist, Edwin Kevin; Ruskin, Jeremy Neil

2018-05-15

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in adults, associated with significant morbidity, increased mortality, and rising health-care costs. Simple and available tools for the accurate detection of arrhythmia recurrence in patients after electrical cardioversion (CV) or ablation procedures for AF can help to guide therapeutic decisions. We conducted a prospective, single-center study to evaluate the accuracy of Cardiio Rhythm Mobile Application (CRMA) for AF detection. Patients >18 years of age who were scheduled for elective CV for AF were enrolled in the study. CRMA finger pulse recordings, utilizing an iPhone camera, were obtained before (pre-CV) and after (post-CV) the CV. The findings were validated against surface electrocardiograms. Ninety-eight patients (75.5% men), mean age of 67.7 ± 10.5 years, were enrolled. No electrocardiogram for validation was available in 1 case. Pre-CV CRMA readings were analyzed in 97 of the 98 patients. Post-CV CRMA readings were analyzed for 92 of 93 patients who underwent CV. One patient left before the recording was obtained. The Cardiio Rhythm Mobile Application correctly identified 94 of 101 AF recordings (93.1%) as AF and 80 of 88 non-AF recordings (90.1%) as non-AF. The sensitivity was 93.1% (95% confidence interval [CI] = 86.9% to 97.2%) and the specificity was 90.9% (95% CI = 82.9% to 96.0%). The positive predictive value was 92.2% (95% CI = 85.8% to 95.8%) and the negative predictive value was 92.0% (95% CI = 94.8% to 95.9%). In conclusion, the CRMA demonstrates promising potential in accurate detection and discrimination of AF from normal sinus rhythm in patients with a history of AF. Copyright © 2018 Elsevier Inc. All rights reserved.

Circadian Rhythm Phase Locking for Traveling Special Forces Operators: Using Light Exposure to Maintain Time Zone Entrainment

DTIC Science & Technology

a circadian phase through the use of controlled light exposures. Eleven male subjects from active duty SOF commands were flown from Guam (UTC 10:00...to Troy, NY (UTC -05:00; 9 hours) while wearing blue- light goggles and blue-blocking, orange-tinted glasses in a carefully-prescribed schedule...designed to maintain entrainment to the desired circadian time (UTC 10:00). Biochemical indices (dim- light melatonin onset) showed that no change in

Analyses and treatments of postoperative nasal complications after endonasal transsphenoidal resection of pituitary neoplasms

PubMed Central

Cheng, You; Xue, Fei; Wang, Tian-You; Ji, Jun-Feng; Chen, Wei; Wang, Zhi-Yi; Xu, Li; Hang, Chun-Hua; Liu, Xin-Feng

2017-01-01

Abstract In this study, we analyze and discuss the treatments of postoperative nasal complications after endonasal transsphenoidal resection of pituitary neoplasms (PNs). We performed 129 endonasal transsphenoidal resections of PNs and analyzed and treated cases with nasal complications. After endonasal transsphenoidal resection of PNs, there were 26 cases of postoperative nasal complications (20.1%), including nasal hemorrhage (4.8%), cerebrospinal fluid rhinorrhea (6.9%), sphenoid sinusitis (2.3%), atrophic rhinitis (1.6%), olfactory disorder (1.6%), perforation of nasal septum (0.8%), and nasal adhesion (2.3%). All patients clinically recovered after therapy, which included treatment of the cavity through nasal endoscopy, intranasal corticosteroids, and nasal irrigation. We propose that regular nasal endoscopic review, specific nasal medications, and regular nasal irrigation can effectively clear nasal mucosal hyperemia-induced edema and nasal/nasoantral secretions, as well as promote regeneration of nasal mucosa, prevent nasal adhesion, maintain the sinus cavity drainage, and accelerate the recovery of the physiological function of the paranasal sinus. Timely treatment of patients with nasal complications after endonasal transsphenoidal resections of PNs could greatly relieve the clinical symptoms. Nasal cleaning is very beneficial to patients after surgery recovery. PMID:28403108

Strict sequential catheter ablation strategy targeting the pulmonary veins and superior vena cava for persistent atrial fibrillation.

PubMed

Yoshiga, Yasuhiro; Shimizu, Akihiko; Ueyama, Takeshi; Ono, Makoto; Fukuda, Masakazu; Fumimoto, Tomoko; Ishiguchi, Hironori; Omuro, Takuya; Kobayashi, Shigeki; Yano, Masafumi

2018-08-01

An effective catheter ablation strategy, beyond pulmonary vein isolation (PVI), for persistent atrial fibrillation (AF) is necessary. Pulmonary vein (PV)-reconduction also causes recurrent atrial tachyarrhythmias. The effect of the PVI and additional effect of a superior vena cava (SVC) isolation (SVCI) was strictly evaluated. Seventy consecutive patients with persistent AF who underwent a strict sequential ablation strategy targeting the PVs and SVC were included in this study. The initial ablation strategy was a circumferential PVI. A segmental SVCI was only applied as a repeat procedure when patients demonstrated no PV-reconduction. After the initial procedure, persistent AF was suppressed in 39 of 70 (55.7%) patients during a median follow-up of 32 months. After multiple procedures, persistent AF was suppressed in 46 (65.7%) and 52 (74.3%) patients after receiving the PVI alone and PVI plus SVCI strategies, respectively. In 6 of 15 (40.0%) patients with persistent AF resistant to PVI, persistent AF was suppressed. The persistent AF duration independently predicted persistent AF recurrences after multiple PVI alone procedures [HR: 1.012 (95% confidence interval: 1.006-1.018); p<0.001] and PVI plus SVCI strategies [HR: 1.018 (95% confidence interval: 1.011-1.025); p<0.001]. A receiver-operating-characteristic analysis for recurrent persistent AF indicated an optimal cut-off value of 20 and 32 months for the persistent AF duration using the PVI alone and PVI plus SVCI strategies, respectively. The outcomes of the PVI plus SVCI strategy were favorable for patients with shorter persistent AF durations. The initial SVCI had the additional effect of maintaining sinus rhythm in some patients with persistent AF resistant to PVI. Copyright © 2018 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Clinically suspected anaphylaxis induced by sugammadex in a patient with Weaver syndrome undergoing restrictive mammoplasty surgery: A case report with the literature review.

PubMed

Bedirli, Nurdan; Işık, Berrin; Bashiri, Mehrnoosh; Pampal, Kutluk; Kurtipek, Ömer

2018-01-01

Sugammadex is a cylodextrin derivate that encapsulates steroidal neuromuscular blocker agents and is reported as a safe and well-tolerated drug. In this case report, we present a patient who developed grade 3 anaphylaxis just after sugammadex administration. A 22-year-old woman with diagnosis of Weaver syndrome was scheduled for bilateral mammoplasty and resection of unilateral accessory breast tissue resection. Anesthesia was induced and maintained by propofol, rocuronium, and remifentanil. At the end of the operation, sugammadex was administered and resulted in initially hypotension and bradycardia then the situation worsened by premature ventricular contraction and bigeminy with tachycardia, bronchospasm, and hypoxia. The Ring and Messmer clinical severity scale grade 3 anaphylactic reaction occurred just after sugammadex injection and the patient developed prolonged hypotension with recurrent cardiac arrhythmias in postoperative 12 hours. Treatment was initiated bolus injections of ephedrine, epinephrine, lidocaine, steroids and antihistaminic and continued with lidocaine bolus dosages and norepinephrine infusion for the postoperative period. The general condition of the patient improved to normal 3 hours after the sugammadex injection, and she was moved to the intensive care unit. At 2nd and 8th hours of intensive care unit follow-up, she developed premature ventricular contraction and bigeminy with the heart rate of 130 to 135 beats/min, which returned to sinus rhythm with 50 mg lidocaine. After that, no symptoms were observed and the patient was discharged to plastic surgery clinic at the following day. Sugammadex may result in life-treating anaphylactic reaction even in a patient who did not previously expose to drug. Moreover, prolonged cardiovascular collapse and cardiac arrhythmias may occur. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Clinically suspected anaphylaxis induced by sugammadex in a patient with Weaver syndrome undergoing restrictive mammoplasty surgery

PubMed Central

Bedirli, Nurdan; Işık, Berrin; Bashiri, Mehrnoosh; Pampal, Kutluk; Kurtipek, Ömer

2018-01-01

Abstract Rationale: Sugammadex is a cylodextrin derivate that encapsulates steroidal neuromuscular blocker agents and is reported as a safe and well-tolerated drug. In this case report, we present a patient who developed grade 3 anaphylaxis just after sugammadex administration. Patient concerns: A 22-year-old woman with diagnosis of Weaver syndrome was scheduled for bilateral mammoplasty and resection of unilateral accessory breast tissue resection. Anesthesia was induced and maintained by propofol, rocuronium, and remifentanil. At the end of the operation, sugammadex was administered and resulted in initially hypotension and bradycardia then the situation worsened by premature ventricular contraction and bigeminy with tachycardia, bronchospasm, and hypoxia. Diagnosis: The Ring and Messmer clinical severity scale grade 3 anaphylactic reaction occurred just after sugammadex injection and the patient developed prolonged hypotension with recurrent cardiac arrhythmias in postoperative 12 hours. Interventions: Treatment was initiated bolus injections of ephedrine, epinephrine, lidocaine, steroids and antihistaminic and continued with lidocaine bolus dosages and norepinephrine infusion for the postoperative period. Outcomes: The general condition of the patient improved to normal 3 hours after the sugammadex injection, and she was moved to the intensive care unit. At 2nd and 8th hours of intensive care unit follow-up, she developed premature ventricular contraction and bigeminy with the heart rate of 130 to 135 beats/min, which returned to sinus rhythm with 50 mg lidocaine. After that, no symptoms were observed and the patient was discharged to plastic surgery clinic at the following day. Lessons: Sugammadex may result in life-treating anaphylactic reaction even in a patient who did not previously expose to drug. Moreover, prolonged cardiovascular collapse and cardiac arrhythmias may occur. PMID:29505006

Hyperglycemia and subsequent torsades de pointes with marked QT prolongation during refeeding.

PubMed

Nakashima, Takashi; Kubota, Tomoki; Takasugi, Nobuhiro; Kitagawa, Yuichiro; Yoshida, Takahiro; Ushikoshi, Hiroaki; Kawasaki, Masanori; Nishigaki, Kazuhiko; Ogura, Shinji; Minatoguchi, Shinya

2017-01-01

A fatal cardiac complication can occasionally present in malnourished patients during refeeding; this is known as refeeding syndrome. However, to our knowledge, hyperglycemia preceding torsades de pointes with QT prolongation during refeeding has not been reported. In the present study, we present a case in which hyperglycemia preceded torsades de pointes with QT prolongation during refeeding. The aim of this study was to determine the possible mechanism underlying QT prolongation during refeeding and indicate how to prevent it. A 32-y-old severely malnourished woman (body mass index 14.57 kg/m 2 ) was admitted to the intensive care unit of our institution after resuscitation from cardiopulmonary arrest due to ventricular fibrillation. She was diagnosed with anorexia nervosa. Although no obvious electrolyte abnormalities were observed, her blood glucose level was 11 mg/dL. A 12-lead electrocardiogram at admission showed sinus rhythm with normal QT interval (QTc 0.448). Forty mL of 50% glucose (containing 20 g of glucose) was intravenously injected, followed by a drip infusion of glucose to maintain blood glucose level within normal range. After 9 h, the patient's blood glucose level increased to 569 mg/dL. However, after 38 h, an episode of marked QT prolongation (QTc 0.931) followed by torsades de pointes developed. Hyperglycemia during refeeding can present with QT prolongation; consequently, monitoring blood glucose levels may be useful in avoiding hyperglycemia, which can result in QT prolongation. Furthermore, additional monitoring of QT intervals using a 12-lead electrocardiogram should allow the early detection of QT prolongation when glucose solution is administered to a malnourished patient with (severe) hypoglycemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Mid-term results of cardiac autotransplantation as method to treat permanent atrial fibrillation and mitral disease.

PubMed

Troise, Giovanni; Cirillo, Marco; Brunelli, Federico; Tasca, Giordano; Amaducci, Andrea; Mhagna, Zen; Tomba, Margherita Dalla; Quaini, Eugenio

2004-06-01

The results of current surgical options for the treatment of permanent atrial fibrillation (AF) associated with mitral surgery are widely different, particularly in very enlarged left atria. The aim of this study was to assess the mid-term efficacy of cardiac autotransplantation for this goal, through a consistent reduction of left atrium volume and a complete isolation of the pulmonary veins. From April 2000 to September 2002, 30 patients (male/female 5/25) underwent cardiac autotransplantation for the treatment of mitral valve disease and concomitant permanent AF (>1 year). Surgical technique of bicaval heart transplantation was modified maintaining the connection of inferior vena cava in all but three cases. Twenty-eight patients had mitral valve replacement and two had mitral valve repair. Associated procedures were: aortic valve replacement (6 cases), tricuspid valve repair (2 cases), coronary re-vascularization (2 cases) and right atrium volume reduction (4 cases). No hospital death occurred; 1 patient died 3 months post-operatively for pneumonia. At a mean follow-up of 21.1+/-7.7 months (range 6-35), 26 patients (89.7%) were in sinus rhythm and 3 (10.3%) in AF. Santa Cruz Score was 0 in 3 patients, 2 in 2 patients and 4 in the remaining 24 patients (82.7%). Mean left atrial diameter and volume decreased from 65.1+/-16.4 mm (range 50-130 mm) to 49.9+/-8.4 mm (range 37-78) (P < 0.001) and from 118.3+/-68.4 ml (range 60-426) to 69.4+/-34.1 ml (range 31-226) (P = 0.001), respectively, after the operation. Cardiac autotransplantation is a safe and effective option for the treatment of permanent AF in patients with mitral valve disease and severe dilation of left atrium.

[Chronic outcome of patients with paroxysmal atrial fibrillation post catheter ablation].

PubMed

Lin, Yu-bi; Xia, Yun-long; Gao, Lian-jun; Chu, Zhen-liang; Cong, Pei-xin; Chang, Dong; Yin, Xiao-meng; Zhang, Shu-long; Yang, Dong-Hui; Yang, Yan-Zong

2009-12-01

High short-term successful rate was reported for catheter ablation in patients with paroxysmal atrial fibrillation (AF), we analyzed the long-term outcome (success rate, anticoagulation therapy and embolism event, anti-arrhythmic therapy and death post procedure) of catheter ablation for paroxysmal AF in this study. From January 2000 to December 2004, 106 consecutive patients with drug-refractory paroxysmal AF underwent catheter ablation and were followed-up for (60.7 + or - 11.8) months. Segmental pulmonary vein isolation (SPVI) was routinely performed by radiofrequency energy under the guidance of circular mapping catheter. The patients were followed up with 24 h-holter, ECG, telephone or letter. Data on recurrence of AF, the anticoagulation medication and the incidence of embolism, anti-arrhythmic therapy were obtained. There were 9 patients lost to follow up. In the remaining 97 patients [65 males, (54.8 + or - 11.2) years old], 3 cases died from cancer, sinus rhythm was maintained in 68 patients (Group S, 72.3%) and AF recurrence evidenced in 26 patients (Group R, 27.7%). In Group S, 56 patients (82.4%) discontinued anticoagulation medication, and 12 patients continued to take aspirin. There was no embolism event in Group S during follow-up. In Group R, 1 patient continued to take warfarin; 11 patients continued to take aspirin and 2 patients suffered from cerebral embolism. Anticoagulation medication was discontinued in 14 patients (53.8%) and 1 patient suffered form cerebral embolism. The incidence of embolism event in Group R is significantly higher than in Group S (P < 0.01). More patients discontinued anti-arrhythmic medication in Group S than in Group R (80.9% vs. 56.0%, P < 0.05). Catheter ablation is associated with satisfactory long-term success rate, reduced anti-arrhythmia medication, improved quality of life in patients with paroxysmal AF.

Atrial Fibrillation and Pulmonary Venous Electrical Conduction Recovery After Full Surgical Resection and Anastomosis of the Pulmonary Veins: Insights From Follow-Up and Ablation Procedures in Lung Transplant Recipients.

PubMed

Hussein, Ayman A; Panchabhai, Tanmay S; Budev, Marie M; Tarakji, Khaldoun; Barakat, Amr F; Saliba, Walid; Lindsay, Bruce; Wazni, Oussama M

2017-06-01

The authors report their experience with atrial fibrillation (AF) rates and ablation findings in lung transplant recipients. Pulmonary venous (PV) conduction recovery accounts for most failed atrial fibrillation (AF) catheter ablation procedures. Lung transplantation involves full surgical resection and replacement of the recipient's PVs with donor's PVs, which may represent the ultimate PV ablation. They followed 755 consecutive lung transplant recipients categorized based on transplant status (unilateral vs. bilateral) and pre-transplant AF. In patients without pre-transplant AF (n = 704), late AF (beyond 6 months after transplant) occurred in 2.5% and 3.3% of unilateral or bilateral lung transplants, respectively. In patients with pre-transplant AF (n = 51), AF recurred in 19.4% and 25.0% of bilateral and unilateral transplants, respectively. In a subset of patients who underwent left atrial ablations after transplant for recurrent refractory AF (n = 8), PV conduction recovery across the surgical anastomoses lines was observed in 22 of 26 previously disconnected PVs. Conduction recovery was observed in ≥1 vein in all but 1 patient. Re-isolation of the veins with additional substrate modification/flutter ablations successfully restored and maintained sinus rhythm in 7 of 8 patients. In lung transplant recipients who undergo full surgical resection of the PVs, a prior history of AF was associated with late AF, regardless of whether patients underwent single or bilateral lung transplantation. PV conduction recovery still occurred and was observed in most patients who underwent left atrial ablation procedures for recurrent AF. Copyright © 2017. Published by Elsevier Inc.

Neural mechanisms of rhythm-based temporal prediction: Delta phase-locking reflects temporal predictability but not rhythmic entrainment.

PubMed

Breska, Assaf; Deouell, Leon Y

2017-02-01

Predicting the timing of upcoming events enables efficient resource allocation and action preparation. Rhythmic streams, such as music, speech, and biological motion, constitute a pervasive source for temporal predictions. Widely accepted entrainment theories postulate that rhythm-based predictions are mediated by synchronizing low-frequency neural oscillations to the rhythm, as indicated by increased phase concentration (PC) of low-frequency neural activity for rhythmic compared to random streams. However, we show here that PC enhancement in scalp recordings is not specific to rhythms but is observed to the same extent in less periodic streams if they enable memory-based prediction. This is inconsistent with the predictions of a computational entrainment model of stronger PC for rhythmic streams. Anticipatory change in alpha activity and facilitation of electroencephalogram (EEG) manifestations of response selection are also comparable between rhythm- and memory-based predictions. However, rhythmic sequences uniquely result in obligatory depression of preparation-related premotor brain activity when an on-beat event is omitted, even when it is strategically beneficial to maintain preparation, leading to larger behavioral costs for violation of prediction. Thus, while our findings undermine the validity of PC as a sign of rhythmic entrainment, they constitute the first electrophysiological dissociation, to our knowledge, between mechanisms of rhythmic predictions and of memory-based predictions: the former obligatorily lead to resonance-like preparation patterns (that are in line with entrainment), while the latter allow flexible resource allocation in time regardless of periodicity in the input. Taken together, they delineate the neural mechanisms of three distinct modes of preparation: continuous vigilance, interval-timing-based prediction and rhythm-based prediction.

Evolution of circadian rhythms in Drosophila melanogaster populations reared in constant light and dark regimes for over 330 generations.

PubMed

Shindey, Radhika; Varma, Vishwanath; Nikhil, K L; Sharma, Vijay Kumar

2017-01-01

Organisms are believed to have evolved circadian clocks as adaptations to deal with cyclic environmental changes, and therefore it has been hypothesized that evolution in constant environments would lead to regression of such clocks. However, previous studies have yielded mixed results, and evolution of circadian clocks under constant conditions has remained an unsettled topic of debate in circadian biology. In continuation of our previous studies, which reported persistence of circadian rhythms in Drosophila melanogaster populations evolving under constant light, here we intended to examine whether circadian clocks and the associated properties evolve differently under constant light and constant darkness. In this regard, we assayed activity-rest, adult emergence and oviposition rhythms of D. melanogaster populations which have been maintained for over 19 years (~330 generations) under three different light regimes - constant light (LL), light-dark cycles of 12:12 h (LD) and constant darkness (DD). We observed that while circadian rhythms in all the three behaviors persist in both LL and DD stocks with no differences in circadian period, they differed in certain aspects of the entrained rhythms when compared to controls reared in rhythmic environment (LD). Interestingly, we also observed that DD stocks have evolved significantly higher robustness or power of free-running activity-rest and adult emergence rhythms compared to LL stocks. Thus, our study, in addition to corroborating previous results of circadian clock evolution in constant light, also highlights that, contrary to the expected regression of circadian clocks, rearing in constant darkness leads to the evolution of more robust circadian clocks which may be attributed to an intrinsic adaptive advantage of circadian clocks and/or pleiotropic functions of clock genes in other traits.

The importance of a daily rhythm in a supportive environment--promoting ability in activities in everyday life among older women living alone with chronic pain.

PubMed

Cederbom, Sara; Wågert, Petra von Heideken; Söderlund, Anne; Söderbäck, Maja

2014-01-01

The aim of this study was to explore how older women living alone with chronic musculoskeletal pain, describe their ability in performing activities in everyday life and what could promote their ability in activities in everyday life as well as their perceived meaning of a changed ability to perform activities in everyday life. Qualitative interviews were conducted with 12 women, and an inductive content analysis was used. The results showed the importance of a daily rhythm of activities. Activities included in the daily rhythm were socializing with family and friends, physical activities, doing own activities as well as activities supported by relatives and the community. The activities described by the women also promoted their ability in activities in everyday life. Other findings were the women's perceived meaning of being independent and maintaining that independency, along with the meaning of accepting and adapting to a changed life situation. This paper concludes that it is important to be sensitive of individual needs regarding the daily rhythm of activities when health-care professionals intervene in the activities in everyday life of older women living alone, promote the women's independency, and enable them to participate in the community. Implications for Rehabilitation A daily rhythm of activities is important for older women who live alone with chronic musculoskeletal pain. The importance of health-care professionals being sensitive to individual needs to promote ability in activities in everyday life and to encourage the everyday activities into a daily rhythm. Facilitate the women's desire and will of independency, despite their needs of help from their environment to manage their everyday life.

Metabolic circadian rhythms in embryonic turtles.

PubMed

Loudon, Fiona Kay; Spencer, Ricky-John; Strassmeyer, Alana; Harland, Karen

2013-07-01

Oviparous species are model organisms for investigating embryonic development of endogenous physiological circadian rhythms without the influence of maternal biorhythms. Recent studies have demonstrated that heart rates and metabolic rates of embryonic turtles are not constant or always maximal and can be altered in response to the presence of embryos at a more advanced stage of development within the nest. A first step in understanding the physiological mechanisms underpinning these responses in embryonic ectothermic organisms is to develop metabolic profiles (e.g., heart rate) at different temperatures throughout incubation. Heart beat and rhythmic patterns or changes in development may represent important signals or cues within a nest and may be vital to coordinate synchronous hatching well in advance of the final stages of incubation. We developed baseline embryonic heart-rate profiles of embryos of the short-necked Murray River turtle (Emydura macquarii) to determine the stage of embryogenesis that metabolic circadian rhythms become established, if at all. Eggs were incubated at constant temperatures (26°C and 30°C) and heart rates were monitored at 6-h intervals over 24 h every 7-11 days until hatching. Circadian heart rate rhythms were detected at the mid-gestation period and were maintained until hatching. Heart rates throughout the day varied by up to 20% over 24 h and were not related to time of day. This study demonstrated that endogenous metabolic circadian rhythms in developing embryos in turtle eggs establish earlier in embryogenesis than those documented in other vertebrate taxa during embryogenesis. Early establishment of circadian rhythms in heart rates may be critical for communication among embryos and synchrony in hatching and emergence from the nest.

Neural mechanisms of rhythm-based temporal prediction: Delta phase-locking reflects temporal predictability but not rhythmic entrainment

PubMed Central

Deouell, Leon Y.

2017-01-01

Predicting the timing of upcoming events enables efficient resource allocation and action preparation. Rhythmic streams, such as music, speech, and biological motion, constitute a pervasive source for temporal predictions. Widely accepted entrainment theories postulate that rhythm-based predictions are mediated by synchronizing low-frequency neural oscillations to the rhythm, as indicated by increased phase concentration (PC) of low-frequency neural activity for rhythmic compared to random streams. However, we show here that PC enhancement in scalp recordings is not specific to rhythms but is observed to the same extent in less periodic streams if they enable memory-based prediction. This is inconsistent with the predictions of a computational entrainment model of stronger PC for rhythmic streams. Anticipatory change in alpha activity and facilitation of electroencephalogram (EEG) manifestations of response selection are also comparable between rhythm- and memory-based predictions. However, rhythmic sequences uniquely result in obligatory depression of preparation-related premotor brain activity when an on-beat event is omitted, even when it is strategically beneficial to maintain preparation, leading to larger behavioral costs for violation of prediction. Thus, while our findings undermine the validity of PC as a sign of rhythmic entrainment, they constitute the first electrophysiological dissociation, to our knowledge, between mechanisms of rhythmic predictions and of memory-based predictions: the former obligatorily lead to resonance-like preparation patterns (that are in line with entrainment), while the latter allow flexible resource allocation in time regardless of periodicity in the input. Taken together, they delineate the neural mechanisms of three distinct modes of preparation: continuous vigilance, interval-timing-based prediction and rhythm-based prediction. PMID:28187128

Hypothalamic orexin prevents hepatic insulin resistance via daily bidirectional regulation of autonomic nervous system in mice.

PubMed

Tsuneki, Hiroshi; Tokai, Emi; Nakamura, Yuya; Takahashi, Keisuke; Fujita, Mikio; Asaoka, Takehiro; Kon, Kanta; Anzawa, Yuuki; Wada, Tsutomu; Takasaki, Ichiro; Kimura, Kumi; Inoue, Hiroshi; Yanagisawa, Masashi; Sakurai, Takeshi; Sasaoka, Toshiyasu

2015-02-01

Circadian rhythm is crucial for preventing hepatic insulin resistance, although the mechanism remains uncovered. Here we report that the wake-active hypothalamic orexin system plays a key role in this regulation. Wild-type mice showed that a daily rhythm in blood glucose levels peaked at the awake period; however, the glucose rhythm disappeared in orexin knockout mice despite normal feeding rhythm. Central administration of orexin A during nighttime awake period acutely elevated blood glucose levels but subsequently lowered daytime glucose levels in normal and diabetic db/db mice. The glucose-elevating and -lowering effects of orexin A were suppressed by adrenergic antagonists and hepatic parasympathectomy, respectively. Moreover, the expression levels of hepatic gluconeogenic genes, including Pepck, were increased and decreased by orexin A at nanomolar and femtomolar doses, respectively. These results indicate that orexin can bidirectionally regulate hepatic gluconeogenesis via control of autonomic balance, leading to generation of the daily blood glucose oscillation. Furthermore, during aging, orexin deficiency enhanced endoplasmic reticulum (ER) stress in the liver and caused impairment of hepatic insulin signaling and abnormal gluconeogenic activity in pyruvate tolerance test. Collectively, the daily glucose rhythm under control of orexin appears to be important for maintaining ER homeostasis, thereby preventing insulin resistance in the liver. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Moving to the Rhythm with Clock (Circadian) Genes, Autophagy, mTOR, and SIRT1 in Degenerative Disease and Cancer.

PubMed

Maiese, Kenneth

2017-01-01

The mammalian circadian clock and its associated clock genes are increasingly been recognized as critical components for a number of physiological and disease processes that extend beyond hormone release, thermal regulation, and sleep-wake cycles. New evidence suggests that clinical behavior disruptions that involve prolonged shift work and even space travel may negatively impact circadian rhythm and lead to multi-system disease. In light of the significant role circadian rhythm can hold over the body's normal physiology as well as disease processes, we examined and discussed the impact circadian rhythm and clock genes hold over lifespan, neurodegenerative disorders, and tumorigenesis. In experimental models, lifespan is significantly reduced with the introduction of arrhythmic mutants and leads to an increase in oxidative stress exposure. Interestingly, patients with Alzheimer's disease and Parkinson's disease may suffer disease onset or progression as a result of alterations in the DNA methylation of clock genes as well as prolonged pharmacological treatment for these disorders that may lead to impairment of circadian rhythm function. Tumorigenesis also can occur with the loss of a maintained circadian rhythm and lead to an increased risk for nasopharyngeal carcinoma, breast cancer, and metastatic colorectal cancer. Interestingly, the circadian clock system relies upon the regulation of the critical pathways of autophagy, the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), and silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1) as well as proliferative mechanisms that involve the wingless pathway of Wnt/β-catenin pathway to foster cell survival during injury and block tumor cell growth. Future targeting of the pathways of autophagy, mTOR, SIRT1, and Wnt that control mammalian circadian rhythm may hold the key for the development of novel and effective therapies against aging- related disorders, neurodegenerative disease, and tumorigenesis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Electromechanical Wave Imaging of biologically and electrically paced canine hearts in vivo

PubMed Central

Costet, Alexandre; Provost, Jean; Gambhir, Alok; Bobkov, Yevgeniy; Danilo, Peter; Boink, Gerard J.J.; Rosen, Michael R.; Konofagou, Elisa

2014-01-01

Ultrasound-based, Electromechanical Wave (EW) Imaging (EWI) can directly and entirely noninvasively map the transmural electromechanical activation in all four cardiac chambers in vivo. In this study, we assessed EWI repeatability and reproducibility, as well as its capability in localizing electronic and, for the first time, biological pacemakers in closed-chest, conscious canines. Electromechanical activation was obtained in six conscious animals during normal sinus rhythm (NSR), and idioventricular rhythms occurring in dogs in heart block instrumented with electronic and biological pacemakers (EPM and BPM respectively). After AV node ablation, dogs were implanted with an EPM in the right ventricular (RV) endocardial apex (n=4) and two additionally received a BPM at the left ventricular (LV) epicardial base (n=2). EWI was performed transthoracically during NSR, BPM, and EPM pacing, in conscious dogs, using an unfocused transmit sequence at 2000 frames/second. During NSR, the EW originated at the right atrium (RA), propagated to the left atrium (LA) and emerged from multiple sources in both ventricles. During EPM, the EW originated at the RV apex and propagated throughout both ventricles. During BPM, the EW originated from the LV basal lateral wall and subsequently propagated throughout the ventricles. EWI differentiated BPM from EPM and NSR and identified the distinct pacing origins. Isochrone comparison demonstrated that EWI was repeatable and reliable. These findings thus indicate the EWI potential to serve as a simple, noninvasive and direct imaging technology for mapping and characterizing arrhythmias as well as the treatments thereof. PMID:24239363

A Clinical Feasibility Study of Atrial and Ventricular Electromechanical Wave Imaging

PubMed Central

Provost, Jean; Gambhir, Alok; Vest, John; Garan, Hasan; Konofagou, Elisa E.

2014-01-01

Background Cardiac Resynchronization Therapy (CRT) and atrial ablation currently lack a noninvasive imaging modality for reliable treatment planning and monitoring. Electromechanical Wave Imaging (EWI) is an ultrasound-based method that has previously been shown to be capable of noninvasively and transmurally mapping the activation sequence of the heart in animal studies by estimating and imaging the electromechanical wave, i.e., the transient strains occurring in response to the electrical activation, at both very high temporal and spatial resolution. Objective Demonstrate the feasibility of noninvasive transthoracic EWI for mapping the activation sequence during different cardiac rhythms in humans. Methods EWI was performed in CRT patients with a left bundle-branch block (LBBB), during sinus rhythm, left-ventricular pacing, and right-ventricular pacing and in atrial flutter (AFL) patients before intervention and correlated with results from invasive intracardiac electrical mapping studies during intervention. Additionally, the feasibility of single-heartbeat EWI at 2000 frames/s, is demonstrated in humans for the first time in a subject with both AFL and right bundle-branch-block. Results The electromechanical activation maps demonstrated the capability of EWI to localize the pacing sites and characterize the LBBB activation sequence transmurally in CRT patients. In AFL patients, the propagation patterns obtained with EWI were in agreement with results obtained from invasive intracardiac mapping studies. Conclusion Our findings demonstrate the potential capability of EWI to aid in monitoring and follow-up of patients undergoing CRT pacing therapy and atrial ablation with preliminary validation in vivo. PMID:23454060

An Unrecognized Rash Progressing to Lyme Carditis: Important Features and Recommendations Regarding Lyme Disease.

PubMed

Lee, Shawn; Singla, Montish

2016-01-01

We present a case report of 46-year-old man with no medical history, who complained of extreme fatigue, near-syncope, and palpitations. He initially presented in complete heart block. A transvenous pacemaker was placed in the emergency department, and he was started empirically on Ceftriaxone for Lyme disease. He was admitted and over the course of the next few days, his rhythm regressed to Mobitz type I first-degree atrioventricular block and then to normal sinus rhythm. This case report highlights some important features regarding Lyme carditis, a rare presentation of early disseminated Lyme disease (seen in a few weeks to months after the initial tick bite). In 25%-30% of patients, the characteristic targetoid rash may not be seen, a likely culprit of the disease not being detected early and progressing to disseminated disease. The most common cardiac complaint of Lyme disease is palpitations, occurring in 6.6% of patients, which may not accurately reflect progression into disseminated Lyme disease because it is a nonspecific finding. Conduction abnormality, occurring in 1.8% of patients, is a more specific finding of Borrelia invading cardiac tissue. Finally, this case report highlights a recommendation that patients with confirmed Lyme disease or those presenting with cardiac abnormalities or symptoms who have an atypical profile for a cardiac event should be screened with a 12-lead electrocardiogram, Lyme serology, and be considered for antibiotic therapy with the possibility of temporary pacing.

The effect of surgical treatment for secundum atrial septal defect in patients more than 30 years old.

PubMed

Erkut, Bilgehan; Becit, Necip; Unlu, Yahya; Ceviz, Munacettin; Kocogullari, Cevdet Ugur; Ates, Azman; Karapolat, Bekir Sami; Kaygin, Mehmet Ali; Kocak, Hikmet

2007-01-01

We prospectively examined whether surgical treatment of secundum atrial septal defects in patients 30 years old improves their early- and mid-term clinical outcomes. Our clinical experience is reviewed to assess the importance of surgical management in elderly patients with atrial septal defect. We analyzed 41 patients older than 30 years of age who underwent surgical correction of a secundum atrial septal defect. To evaluate the effects of surgical treatment, we compared functional capacity, diuretic administration, rhythm status, and echocardiographic parameters of all patients before and after the operation. The median follow-up period was 4.2 years (range, 6 months-7 years). There were no operative deaths. Functional class in most of the patients improved after operation. Two patients reverted to normal sinus rhythm after the operation. There was only one new atrial fibrilation among patients in the postoperative term. Right atrial and right ventricular dimensions and pulmonary artery pressures were significantly decreased, and ejection fractions were significantly increased after the operation. The need for diuretic treatment was decreased after surgical repair. No residual intracardiac shunts were identified during follow-up. There were no cerebrovascular thromboembolic accidents in the early postoperative period. Surgical closure of atrial septal defects in patients over 30 years old can improve their clinical status and prevent right ventricular dilatation and insufficiency. The operation must be performed as soon as possible, even if the symptoms or the hemodynamic impact seem to be minimal.

[Psychophysiological monitoring of women teachers at the turn of the body of middle and old age.

PubMed

Dolgova, V I; Mamylina, N V

2017-01-01

Objective - to create and hold psychophysiological monitoring elderly organism female teachers in the school year dynamics. The study was conducted with the participation of 30 female teachers aged 60-61 years at the beginning of the year (background level) and 5, and 9 months of teaching in the school. We studied 5-minute recording portions of the electrocardiogram using a program «Poly-Spectrum-Rhythm» (the limited liability company «Neurosoft»); lung function - using the apparatus «Spirosoft-5000»; psycho-emotional state of teachers in the dynamics of the school year - on the method of SUN (state of health, activity, mood). By the end of the school year biased increased sympathetic influence of the autonomic nervous system on the body of teachers that have been associated with some violation of the rhythmic activity of the heart on the background of destabilization of sinus rhythm and vegetative balance of the organism; indicators of forced expiratory volume in the first second the teachers were not significantly below baseline values, indicating a decline in the functional reserves of the respiratory system; there has been a strong tendency to deterioration of mental and emotional state of women teachers elderly. Consequently, the dynamics of the school year it is advisable to monitor the activities of the body of female teachers the elderly with a view to the possible prevention of various diseases and abnormalities in health status.

Implanted near-infrared spectroscopy for cardiac monitoring

NASA Astrophysics Data System (ADS)

Bhunia, Sourav K.; Cinbis, Can

2011-02-01

Implanted Cardioverter Defibrillator (ICD) provides one of the most effective therapies for the prevention of sudden cardiac death, but also delivers some high voltage shocks inappropriately, causing morbidity and mortality. Implanted near-infrared spectroscopy (NIRS) may augment ICD arrhythmia detection by monitoring skeletal muscle perfusion. A two-wavelength, single-distance, continuous-wave implanted NIRS has been evaluated in-vivo. A weighted difference of the changes in attenuation at two wavelengths, across the isobestic point of the hemoglobin spectra, was taken to be the microvascular oxygenation trend indicator (O2 Index). Although the exact weight depends on the local vascular distribution and their oxygen levels, the hypothesis that a constant weight may be adequate for hemodynamic trending during short arrhythmic episodes, was tested. The sensor was implanted subcutaneously both on fresh tissue and inside scar tissue that formed around a pre-existing implant, in 3 animals each. Attenuations were recorded at 660 and 890 nm during normal sinus rhythm (NSR) and induced ventricular fibrillation (VF). The slope of the O2 Index over 10 seconds was computed for 7 NSR and 8 VF episodes in fresh and 13 NSR and 15 VF episodes in scar tissue pockets. The mean O2 Index slope was significantly different (p<0.0001) between NSR and VF rhythms for both the fresh and scar tissue pockets. Therefore implanted NIRS may be useful for preventing inappropriate detection of VF during electromagnetic interference, double counting of ECG T-wave as an R-wave, ICD lead failure, electrocardiographic aberrancy etc.

Management of atrial fibrillation: focus on the role of dronedarone.

PubMed

Cheng, Judy Wm

2011-01-01

Dronedarone is an amiodarone derivative that was approved in the US in July 2009 to reduce the risk of cardiovascular hospitalization in patients with paroxysmal or persistent atrial fibrillation (AF), who are in sinus rhythm (SR), or who will be cardioverted. This article reviews the pharmacology, adverse effects, and clinical evidence available to date on the use of dronedarone in the management of AF and its potential role in the emergency department setting. In the EURIDIS and ADONIS studies evaluating the efficacy of dronedarone in maintaining SR, dronedarone significantly reduced the risk of recurrence of AF compared to placebo, by 22% and 27%, respectively. The ERATO study examined the ability of dronedarone to control ventricular rate in permanent AF. The DIONYSOS study demonstrated that recurrences of AF were more frequent with dronedarone. However, discontinuation of therapy due to intolerance was more frequent with amiodarone. Furthermore, the ATHENA study demonstrated that dronedarone reduced mortality and cardiovascular hospitalization by 24% (P < 0.05) in patients in SR but with other associated risks and a history of AF. However, the ANDROMEDA study, evaluating the use of dronedarone in patients with recent decompensated heart failure, and the PALLAS study, evaluating the use of dronedarone in patients with chronic AF, were both terminated prematurely due to a trend toward an increased risk of cardiovascular events. Dronedarone has been demonstrated to be effective in reducing the incidence of AF recurrence. It appears to be less effective but better tolerated than amiodarone. Dronedarone appears to have a low proarrhythmic risk and is the first anti-arrhythmic that has been demonstrated to reduce cardiovascular mortality and cardiovascular hospitalization in clinically stable patients with other risk factors for recurrent AF. Therefore, dronedarone can be recommended as an anti-arrhythmic of choice in clinically stable patients for maintaining SR. If dronedarone is to be used in a patient with chronic stable heart failure, the patient must be monitored closely for any worsening of heart failure symptoms. The drug must be discontinued should the heart failure symptoms worsen.

Left-to-right atrial inward rectifier potassium current gradients in patients with paroxysmal versus chronic atrial fibrillation.

PubMed

Voigt, Niels; Trausch, Anne; Knaut, Michael; Matschke, Klaus; Varró, András; Van Wagoner, David R; Nattel, Stanley; Ravens, Ursula; Dobrev, Dobromir

2010-10-01

Recent evidence suggests that atrial fibrillation (AF) is maintained by high-frequency reentrant sources with a left-to-right-dominant frequency gradient, particularly in patients with paroxysmal AF (pAF). Unequal left-to-right distribution of inward rectifier K(+) currents has been suggested to underlie this dominant frequency gradient, but this hypothesis has never been tested in humans. Currents were measured with whole-cell voltage-clamp in cardiomyocytes from right atrial (RA) and left (LA) atrial appendages of patients in sinus rhythm (SR) and patients with AF undergoing cardiac surgery. Western blot was used to quantify protein expression of I(K1) (Kir2.1 and Kir2.3) and I(K,ACh) (Kir3.1 and Kir3.4) subunits. Basal current was ≈2-fold larger in chronic AF (cAF) versus SR patients, without RA-LA differences. In pAF, basal current was ≈2-fold larger in LA versus RA, indicating a left-to-right atrial gradient. In both atria, Kir2.1 expression was ≈2-fold greater in cAF but comparable in pAF versus SR. Kir2.3 levels were unchanged in cAF and RA-pAF but showed a 51% decrease in LA-pAF. In SR, carbachol-activated (2 μmol/L) I(K,ACh) was 70% larger in RA versus LA. This right-to-left atrial gradient was decreased in pAF and cAF caused by reduced I(K,ACh) in RA only. Similarly, in SR, Kir3.1 and Kir3.4 proteins were greater in RA versus LA and decreased in RA of pAF and cAF. Kir3.1 and Kir3.4 expression was unchanged in LA of pAF and cAF. Our results support the hypothesis that a left-to-right gradient in inward rectifier background current contributes to high-frequency sources in LA that maintain pAF. These findings have potentially important implications for development of atrial-selective therapeutic approaches.

Left-to-Right Atrial Inward Rectifier Potassium Current Gradients in Patients With Paroxysmal Versus Chronic Atrial Fibrillation

PubMed Central

Voigt, Niels; Trausch, Anne; Knaut, Michael; Matschke, Klaus; Varró, András; Van Wagoner, David R.; Nattel, Stanley; Ravens, Ursula; Dobrev, Dobromir

2018-01-01

Background Recent evidence suggests that atrial fibrillation (AF) is maintained by high-frequency reentrant sources with a left-to-right–dominant frequency gradient, particularly in patients with paroxysmal AF (pAF). Unequal left-to-right distribution of inward rectifier K+ currents has been suggested to underlie this dominant frequency gradient, but this hypothesis has never been tested in humans. Methods and Results Currents were measured with whole-cell voltage-clamp in cardiomyocytes from right atrial (RA) and left (LA) atrial appendages of patients in sinus rhythm (SR) and patients with AF undergoing cardiac surgery. Western blot was used to quantify protein expression of IK1 (Kir2.1 and Kir2.3) and IK,ACh (Kir3.1 and Kir3.4) subunits. Basal current was ≈2-fold larger in chronic AF (cAF) versus SR patients, without RA-LA differences. In pAF, basal current was ≈2-fold larger in LA versus RA, indicating a left-to-right atrial gradient. In both atria, Kir2.1 expression was ≈2-fold greater in cAF but comparable in pAF versus SR. Kir2.3 levels were unchanged in cAF and RA-pAF but showed a 51% decrease in LA-pAF. In SR, carbachol-activated (2 μmol/L) IK,ACh was 70% larger in RA versus LA. This right-to-left atrial gradient was decreased in pAF and cAF caused by reduced IK,ACh in RA only. Similarly, in SR, Kir3.1 and Kir3.4 proteins were greater in RA versus LA and decreased in RA of pAF and cAF. Kir3.1 and Kir3.4 expression was unchanged in LA of pAF and cAF. Conclusions Our results support the hypothesis that a left-to-right gradient in inward rectifier background current contributes to high-frequency sources in LA that maintain pAF. These findings have potentially important implications for development of atrial-selective therapeutic approaches. PMID:20657029

Nitric oxide-mediated intersegmental modulation of cycle frequency in the crayfish swimmeret system.

PubMed

Yoshida, Misaki; Nagayama, Toshiki; Newland, Philip

2018-05-21

Crayfish swimmerets are paired appendages located on the ventral side of each abdominal segment that show rhythmic beating during forward swimming produced by central pattern generators in most abdominal segments. For animals with multiple body segments and limbs, intersegmental coordination of central pattern generators in each segment is crucial for the production of effective movements. Here we develop a novel pharmacological approach to analyse intersegmental modulation of swimmeret rhythm by selectively elevating nitric oxide levels and reducing them with pharmacological agents, in specific ganglia. Bath application of L-arginine, the substrate NO synthesis, increased the cyclical spike responses of the power-stroke motor neurons. By contrast the NOS inhibitor, L-NAME decreased them. To determine the role of the different local centres in producing and controlling the swimmeret rhythm, these two drugs were applied locally to two separate ganglia following bath application of carbachol. Results revealed that there was both ascending and descending intersegmental modulation of cycle frequency of the swimmeret rhythm in the abdominal ganglia and that synchrony of cyclical activity between segments of segments was maintained. We also found that there were gradients in the strength effectiveness in modulation, that ascending modulation of the swimmeret rhythm was stronger than descending modulation. © 2018. Published by The Company of Biologists Ltd.