[Ventricular fibrillation following deodorant spray inhalation].

PubMed

Girard, F; Le Tacon, S; Maria, M; Pierrard, O; Monin, P

2008-01-01

We report one case of out-of-hospital cardiac arrest with ventricular fibrillation following butane poisoning after inhalation of antiperspiration aerosol. An early management using semi-automatic defibrillator explained the success of the resuscitation. The mechanism of butane toxicity could be an increased sensitivity of cardiac receptors to circulating catecholamines, responsible for cardiac arrest during exercise and for resuscitation difficulties. The indication of epinephrine is discussed.

Ventricular fibrillation development following atrial fibrillation after the ingestion of sildenaphil in a patient with Wolff-Parkinson-White syndrome

PubMed Central

Inci, Sinan; Izgu, Ibrahim; Aktas, Halil; Dogan, Pinar; Dogan, Ali

2015-01-01

Summary Complications in the accessory pathway in Wolff-Parkinson-White (WPW) syndrome could cause different clinical conditions by inducing different arrhythmias. Atrial fibrillation (AF) is one of these arrhythmias and is important as it causes life-threatening arrhythmias. It is known that some drugs, underlying cardiac diseases, and the number of accessory pathways, cause a predisposition to this condition. In the current report, we presented a patient with WPW who was admitted to the emergency department with AF, wide QRS and a rapid ventricular response that progressed to ventricular fibrillation. PMID:26361569

Ventricular fibrillation development following atrial fibrillation after the ingestion of sildenaphil in a patient with Wolff-Parkinson-White syndrome.

PubMed

Inci, Sinan; Izgu, Ibrahim; Aktas, Halil; Dogan, Pinar; Dogan, Ali

2015-08-01

Complications in the accessory pathway in Wolff-Parkinson-White (WPW) syndrome could cause different clinical conditions by inducing different arrhythmias. Atrial fibrillation (AF) is one of these arrhythmias and is important as it causes life-threatening arrhythmias. It is known that some drugs, underlying cardiac diseases, and the number of accessory pathways, cause a predisposition to this condition. In the current report, we presented a patient with WPW who was admitted to the emergency department with AF, wide QRS and a rapid ventricular response that progressed to ventricular fibrillation.

Managing cardiac arrest with refractory ventricular fibrillation in the emergency department: Conventional cardiopulmonary resuscitation versus extracorporeal cardiopulmonary resuscitation.

PubMed

Siao, Fu-Yuan; Chiu, Chun-Chieh; Chiu, Chun-Wen; Chen, Ying-Chen; Chen, Yao-Li; Hsieh, Yung-Kun; Lee, Chien-Hui; Wu, Chang-Te; Chou, Chu-Chung; Yen, Hsu-Heng

2015-07-01

Refractory ventricular fibrillation, resistant to conventional cardiopulmonary resuscitation (CPR), is a life threatening rhythm encountered in the emergency department. Although previous reports suggest the use of extracorporeal CPR can improve the clinical outcomes in patients with prolonged cardiac arrest, the effectiveness of this novel strategy for refractory ventricular fibrillation is not known. We aimed to compare the clinical outcomes of patients with refractory ventricular fibrillation managed with conventional CPR or extracorporeal CPR in our institution. This is a retrospective chart review study from an emergency department in a tertiary referral medical center. We identified 209 patients presenting with cardiac arrest due to ventricular fibrillation between September 2011 and September 2013. Of these, 60 patients were enrolled with ventricular fibrillation refractory to resuscitation for more than 10 min. The clinical outcome of patients with ventricular fibrillation received either conventional CPR, including defibrillation, chest compression, and resuscitative medication (C-CPR, n = 40) or CPR plus extracorporeal CPR (E-CPR, n = 20) were compared. The overall survival rate was 35%, and 18.3% of patients were discharged with good neurological function. The mean duration of CPR was longer in the E-CPR group than in the C-CPR group (69.90 ± 49.6 min vs 34.3 ± 17.7 min, p = 0.0001). Patients receiving E-CPR had significantly higher rates of sustained return of spontaneous circulation (95.0% vs 47.5%, p = 0.0009), and good neurological function at discharge (40.0% vs 7.5%, p = 0.0067). The survival rate in the E-CPR group was higher (50% vs 27.5%, p = 0.1512) at discharge and (50% vs 20%, p = 0. 0998) at 1 year after discharge. The management of refractory ventricular fibrillation in the emergency department remains challenging, as evidenced by an overall survival rate of 35% in this study. Patients with refractory ventricular fibrillation receiving E

Characteristics and clinical assessment of unexplained sudden cardiac arrest in the real-world setting: focus on idiopathic ventricular fibrillation.

PubMed

Waldmann, Victor; Bougouin, Wulfran; Karam, Nicole; Dumas, Florence; Sharifzadehgan, Ardalan; Gandjbakhch, Estelle; Algalarrondo, Vincent; Narayanan, Kumar; Zhao, Alexandre; Amet, Denis; Jost, Daniel; Geri, Guillaume; Lamhaut, Lionel; Beganton, Frankie; Ludes, Bertrand; Bruneval, Patrick; Plu, Isabelle; Hidden-Lucet, Françoise; Albuisson, Juliette; Lavergne, Thomas; Piot, Olivier; Alonso, Christine; Leenhardt, Antoine; Lellouche, Nicolas; Extramiana, Fabrice; Cariou, Alain; Jouven, Xavier; Marijon, Eloi

2018-06-01

Recent studies have shown that in more than half of apparently unexplained sudden cardiac arrests (SCA), a specific aetiology can be unmasked by a careful evaluation. The characteristics and the extent to which such cases undergo a systematic thorough investigation in real-life practice are unknown. Data were analysed from an ongoing study, collecting all cases of out-of-hospital cardiac arrest in Paris area. Investigations performed during the index hospitalization or planned after discharge were gathered to evaluate the completeness of assessment of unexplained SCA. Between 2011 and 2016, among the 18 622 out-of-hospital cardiac arrests, 717 survivors (at hospital discharge) fulfilled the definition of cardiac SCA. Of those, 88 (12.3%) remained unexplained after electrocardiogram, echocardiography, and coronary angiography. Cardiac magnetic resonance imaging yielded the diagnosis in 25 (3.5%) cases, other investigations accounted for 14 (2.4%) additional diagnoses, and 49 (6.8%) patients were labelled as idiopathic ventricular fibrillation (IVF) (48.7 ± 15 years, 69.4% male). Among those labelled IVF, only 8 (16.3%) cases benefited from a complete workup (including pharmacological testing). Younger patients [odds ratio (OR) 6.00, 95% confidence interval (CI) 1.80-22.26] and those admitted to university centres (OR 3.60, 95% CI 1.12-12.45) were more thoroughly investigated. Genetic testing and family screening were initiated in only 9 (18.4%) and 12 (24.5%) cases, respectively. Our findings suggest that complete investigations are carried out in a very low proportion of unexplained SCA. Standardized, systematic approaches need to be implemented to ensure that opportunities for specific therapies and preventive strategies (including relatives) are not missed.

A Rat Model of Ventricular Fibrillation and Resuscitation by Conventional Closed-chest Technique

PubMed Central

Lamoureux, Lorissa; Radhakrishnan, Jeejabai; Gazmuri, Raúl J.

2015-01-01

A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic components of cardiopulmonary resuscitation in humans is herein described. The model was developed in 1988 and has been used in approximately 70 peer-reviewed publications examining a myriad of resuscitation aspects including its physiology and pathophysiology, determinants of resuscitability, pharmacologic interventions, and even the effects of cell therapies. The model featured in this presentation includes: (1) vascular catheterization to measure aortic and right atrial pressures, to measure cardiac output by thermodilution, and to electrically induce ventricular fibrillation; and (2) tracheal intubation for positive pressure ventilation with oxygen enriched gas and assessment of the end-tidal CO2. A typical sequence of intervention entails: (1) electrical induction of ventricular fibrillation, (2) chest compression using a mechanical piston device concomitantly with positive pressure ventilation delivering oxygen-enriched gas, (3) electrical shocks to terminate ventricular fibrillation and reestablish cardiac activity, (4) assessment of post-resuscitation hemodynamic and metabolic function, and (5) assessment of survival and recovery of organ function. A robust inventory of measurements is available that includes – but is not limited to – hemodynamic, metabolic, and tissue measurements. The model has been highly effective in developing new resuscitation concepts and examining novel therapeutic interventions before their testing in larger and translationally more relevant animal models of cardiac arrest and resuscitation. PMID:25938619

Ventricular fibrillation in an ambulatory patient supported by a left ventricular assist device: highlighting the ICD controversy.

PubMed

Boilson, Barry A; Durham, Lucian A; Park, Soon J

2012-01-01

Left ventricular assist devices (LVADs) provide an effective means of managing advanced pump failure as a means of bridging to cardiac transplantation or as permanent therapy. Although ventricular arrhythmias remain common post-LVAD implantation, such therapy may allow malignant arrhythmias to be tolerated hemodynamically. This report describes the clinical findings in a patient who had likely been in a ventricular tachyarrhythmia for several days and presented in ventricular fibrillation, ambulatory, and mentating normally. This report, with previous similar reports, is additive to the body of evidence that LVADs alter the physiologic impact of ventricular arrhythmias in advanced heart failure and highlights the need for thoughtful programming of implantable cardioverter defibrillator therapies in these patients.

Evolving J waves prior to ventricular fibrillation postoperative coronary bypass.

PubMed

Kitazawa, Hitoshi; Wakasugi, Takayuki; Sugimoto, Tsutomu; Yamamoto, Kazuo; Yoshii, Shinpei; Aizawa, Yoshifusa

2011-01-01

A 74-year-old man without history of ventricular arrhythmias underwent coronary bypass surgery for 3-vessel disease. On the 4th postoperative day, he developed ventricular fibrillation (VF). His monitored ECG showed no elevation of the ST-segment and no prolongation of QT interval, but evolving J waves prior to VF were shown. These J waves gradually decreased after defibrillation. The subsequent angiography revealed patent grafts and normal left ventricular function. J waves reappeared in inferior leads when contrast medium was injected into the coronary artery. Therefore, evolving J wave can be a marker of latent ischemia and a predictor of VF.

Characteristics and clinical assessment of unexplained sudden cardiac arrest in the real-world setting: focus on idiopathic ventricular fibrillation

PubMed Central

Waldmann, Victor; Bougouin, Wulfran; Karam, Nicole; Dumas, Florence; Sharifzadehgan, Ardalan; Gandjbakhch, Estelle; Algalarrondo, Vincent; Narayanan, Kumar; Zhao, Alexandre; Amet, Denis; Jost, Daniel; Geri, Guillaume; Lamhaut, Lionel; Beganton, Frankie; Ludes, Bertrand; Bruneval, Patrick; Plu, Isabelle; Hidden-Lucet, Françoise; Albuisson, Juliette; Lavergne, Thomas; Piot, Olivier; Alonso, Christine; Leenhardt, Antoine; Lellouche, Nicolas; Extramiana, Fabrice; Cariou, Alain; Jouven, Xavier; Marijon, Eloi

2018-01-01

Abstract Aims Recent studies have shown that in more than half of apparently unexplained sudden cardiac arrests (SCA), a specific aetiology can be unmasked by a careful evaluation. The characteristics and the extent to which such cases undergo a systematic thorough investigation in real-life practice are unknown. Methods and results Data were analysed from an ongoing study, collecting all cases of out-of-hospital cardiac arrest in Paris area. Investigations performed during the index hospitalization or planned after discharge were gathered to evaluate the completeness of assessment of unexplained SCA. Between 2011 and 2016, among the 18 622 out-of-hospital cardiac arrests, 717 survivors (at hospital discharge) fulfilled the definition of cardiac SCA. Of those, 88 (12.3%) remained unexplained after electrocardiogram, echocardiography, and coronary angiography. Cardiac magnetic resonance imaging yielded the diagnosis in 25 (3.5%) cases, other investigations accounted for 14 (2.4%) additional diagnoses, and 49 (6.8%) patients were labelled as idiopathic ventricular fibrillation (IVF) (48.7 ± 15 years, 69.4% male). Among those labelled IVF, only 8 (16.3%) cases benefited from a complete workup (including pharmacological testing). Younger patients [odds ratio (OR) 6.00, 95% confidence interval (CI) 1.80–22.26] and those admitted to university centres (OR 3.60, 95% CI 1.12–12.45) were more thoroughly investigated. Genetic testing and family screening were initiated in only 9 (18.4%) and 12 (24.5%) cases, respectively. Conclusion Our findings suggest that complete investigations are carried out in a very low proportion of unexplained SCA. Standardized, systematic approaches need to be implemented to ensure that opportunities for specific therapies and preventive strategies (including relatives) are not missed. PMID:29566157

Magnetic resonance imaging during untreated ventricular fibrillation reveals prompt right ventricular overdistention without left ventricular volume loss.

PubMed

Berg, Robert A; Sorrell, Vincent L; Kern, Karl B; Hilwig, Ronald W; Altbach, Maria I; Hayes, Melinda M; Bates, Kathryn A; Ewy, Gordon A

2005-03-08

Most out-of-hospital ventricular fibrillation (VF) is prolonged (>5 minutes), and defibrillation from prolonged VF typically results in asystole or pulseless electrical activity. Recent visual epicardial observations in an open-chest, open-pericardium model of swine VF indicate that blood flows from the high-pressure arterial system to the lower-pressure venous system during untreated VF, thereby overdistending the right ventricle and apparently decreasing left ventricular size. Therefore, inadequate left ventricular stroke volume after defibrillation from prolonged VF has been postulated as a major contributor to the development of pulseless rhythms. Ventricular dimensions were determined by MRI for 30 minutes of untreated VF in a closed-chest, closed-pericardium model in 6 swine. Within 1 minute of untreated VF, mean right ventricular volume increased by 29% but did not increase thereafter. During the first 5 minutes of untreated VF, mean left ventricular volume increased by 34%. Between 20 and 30 minutes of VF, stone heart occurred as manifested by dramatic thickening of the myocardium and concomitant substantial decreases in left ventricular volume. In this closed-chest swine model of VF, substantial right ventricular volume changes occurred early and did not result in smaller left ventricular volumes. The changes in ventricular volumes before the late development of stone heart do not explain why defibrillation from brief duration VF (<5 minutes) typically results in a pulsatile rhythm with return of spontaneous circulation, whereas defibrillation from prolonged VF (5 to 15 minutes) does not.

Clinical significance of fragmented QRS complexes or J waves in patients with idiopathic ventricular arrhythmias.

PubMed

Seong, Choong Sil; Gwag, Hye Bin; Hwang, Jin Kyung; Park, Seung Jung; Park, Kyoung-Min; Kim, June Soo; On, Young Keun

2018-01-01

Idiopathic ventricular fibrillation (IVF) can cause sudden cardiac death. Previous studies have reported that J waves and fragmented QRS complexes (f-QRS) are arrhythmogenic markers and predictors of cardiac events. We evaluated the prevalence and clinical significance of J waves and f-QRS in patients with IVF. We studied 81 patients who received an implantable cardioverter defibrillator (ICD) due to IVF between October 1999 and June 2015. We assessed the prevalence of J waves and f-QRS using electrocardiograms (ECGs). Patients were classified into three groups: J wave group (n = 35), f-QRS group (n = 20), or normal ECG group (n = 26). The control group included 81 subjects without heart disease who were matched for age, sex, and race. We compared syncope, sudden cardiac arrest, and appropriate ICD shock between the three groups. The follow-up duration was 4.1 years. J waves and f-QRS were more frequent in patients with IVF than in control subjects (43.2%, 21% vs. 24.7%, 19.7%, P < 0.001). Out of the three groups, clinical cardiac events were most frequent in the f-QRS group (50% vs. 45.7% vs. 11.5%, P = 0.028). A comparison of the combined group of J wave and f-QRS versus the normal ECG group revealed that the combined group had a higher frequency of clinical cardiac events than the normal ECG group (47.3% vs. 11.5%, respectively, P = 0.009). Patients with IVF had higher prevalence of f-QRS or J waves. And patients with f-QRS or J waves were at higher risk of recurrent ventricular fibrillation.

Global Bi-ventricular endocardial distribution of activation rate during long duration ventricular fibrillation in normal and heart failure canines.

PubMed

Luo, Qingzhi; Jin, Qi; Zhang, Ning; Han, Yanxin; Wang, Yilong; Huang, Shangwei; Lin, Changjian; Ling, Tianyou; Chen, Kang; Pan, Wenqi; Wu, Liqun

2017-04-13

The objective of this study was to detect differences in the distribution of the left and right ventricle (LV & RV) activation rate (AR) during short-duration ventricular fibrillation (SDVF, <1 min) and long-duration ventricular fibrillation VF (LDVF, >1 min) in normal and heart failure (HF) canine hearts. Ventricular fibrillation (VF) was electrically induced in six healthy dogs (control group) and six dogs with right ventricular pacing-induced congestive HF (HF group). Two 64-electrode basket catheters deployed in the LV and RV were used for global endocardium electrical mapping. The AR of VF was estimated by fast Fourier transform analysis from each electrode. In the control group, the LV was activated faster than the RV in the first 20 s, after which there was no detectable difference in the AR between them. When analyzing the distribution of the AR within the bi-ventricles at 3 min of LDVF, the posterior LV was activated fastest, while the anterior was slowest. In the HF group, a detectable AR gradient existed between the two ventricles within 3 min of VF, with the LV activating more quickly than the RV. When analyzing the distribution of the AR within the bi-ventricles at 3 min of LDVF, the septum of the LV was activated fastest, while the anterior was activated slowest. A global bi-ventricular endocardial AR gradient existed within the first 20 s of VF but disappeared in the LDVF in healthy hearts. However, the AR gradient was always observed in both SDVF and LDVF in HF hearts. The findings of this study suggest that LDVF in HF hearts can be maintained differently from normal hearts, which accordingly should lead to the development of different management strategies for LDVF resuscitation.

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

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.

Ventricular fibrillation induced by coagulating mode bipolar electrocautery during pacemaker implantation in Myotonic Dystrophy type 1 patient.

PubMed

Russo, Vincenzo; Rago, Anna; DI Meo, Federica; Cioppa, Nadia Della; Papa, Andrea Antonio; Russo, Maria Giovanna; Nigro, Gerardo

2014-12-01

The occurrence of ventricular fibrillation, induced by bipolar electrocautery during elective dual chamber pacemaker implantation, is reported in a patient affected by Myotonic Distrophy type 1 with normal left ventricular ejection fraction.

Ventricular fibrillation and the use of automated external defibrillators on children.

PubMed

Markenson, David

2007-11-01

The use of automated external defibrillators (AEDs) has been advocated in recent years as one part of the chain of survival to improve outcomes for adult cardiac arrest victims. When AEDs first entered the market, they had not been tested for pediatric usage and rhythm interpretation. In addition, the presumption was that children do not experience ventricular fibrillation, so they would not benefit from the use of AEDs. Recent literature has shown that children do experience ventricular fibrillation, which has a better outcome than do other cardiac arrest rhythms. At the same time, the arrhythmia software on AEDs has become more extensive and validated for children, and attenuation devices have become available to downregulate the energy delivered by AEDs to allow their use on children. Pediatricians are now being asked whether AED programs should be implemented, and where they are being implemented, pediatricians are being asked to provide guidance on the use of them on children. As AED programs expand, pediatricians must advocate on behalf of children so that their needs are accounted for. For pediatricians to be able to provide guidance and ensure that children are included in AED programs, it is important for pediatricians to know how AEDs work, be up-to-date on the literature regarding pediatric fibrillation and energy delivery, and understand the role of AEDs as life-saving interventions for children.

Increased release of brain serotonin reduces vulnerability to ventricular fibrillation in the cat

NASA Technical Reports Server (NTRS)

Lehnert, Hendrik; Lombardi, Federico; Raeder, Ernst A.; Lorenzo, Antonio V.; Verrier, Richard L.; Lown, Bernard; Wurtman, Richard J.

1987-01-01

The effect of administering the serotonin precursor 5-l-hydroxytryptophan, in conjunction with a monamine oxidase inhibitor phenelzine and a l-amino acid decarboxylase inhibitor carbidopa, on neurochemical changes in the concentrations of serotonin and 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid of the cat were investigated. Results showed that this drug regimen led to increases of serotonin and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the cerebrospinal fluid by 330 and 830 percent, respectively. Concomitantly, the threshold of ventricular fibrillation was found to be elevated by 42 percent and the effective refractory period was prolonged by 7 percent; the efferent sympathetic neural activity was suppressed in the normal heart. The results indicate that the enhancement of central serotoninergic neurotransmission can reduce the susceptibility of the heart to ventricular fibrillation mediated through a decline in sympathetic neural traffic to the heart.

[Idiopathic ventricular arrhythmia in children. Apropos of 24 cases].

PubMed

Coeurderoy, A; Almange, C; Laurent, M; Biron, Y; Leborgne, P

1985-12-01

The severity and prognosis of idiopathic ventricular arrhythmias in childhood were studied in 24 patients (12 boys, 12 girls) with an average age of 8 years at the time of diagnosis of the arrhythmia. Investigations included clinical assessment and analysis of basal ECG (morphology of the arrhythmias) and dynamic recordings (Holter and exercise stress testing). The clinical course was followed for an average of 3.8 years. The patients were classified in two groups: monomorphic arrhythmias (Group I) and polymorphic arrhythmias (Group II). Group I was divided into 4 subgroups: isolated ventricular extrasystoles (IA), 11 patients; ventricular extrasystoles with bursts of ventricular tachycardia (IB), 6 patients; sustained ventricular tachycardia without intercritical extrasystoles (IC), 1 patient; accelerated idioventricular rhythm (ID), 2 patients. Subgroups IA, IB and ID were characterised by the absence of symptoms, the disappearance of the arrhythmia on exercise, the decreased efficacy of antiarrhythmic drugs and an excellent prognosis. Therapeutic abstention was the rule in these patients. Patients in Group IC were characterised by the variability of their symptoms, the absence of exercise induced arrhythmias, the need for treatment in most cases and a good long-term prognosis. Group II was divided into 2 subgroups: adrenergic polymorphic ventricular tachycardia (IIA), 2 patients, and non-adrenergic polymorphic ventricular tachycardia (IIB), 2 patients. Patients in Subgroup IIA were characterised by syncope on exercise or emotion, the need for betablocker therapy which considerably improved the patients symptoms but which did not usually prevent sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)

10-year follow-up after radiofrequency ablation of idiopathic ventricular arrhythmias from right ventricular outflow tract.

PubMed

Rørvik, Synne Dragesund; Chen, Jian; Hoff, Per Ivar; Solheim, Eivind; Schuster, Peter

The aim of this study was to examine the effect of radiofrequency ablation (RFA) of ventricular arrhythmias from right ventricular outflow tract (RVOT) during long-term follow-up. A follow-up analysis was conducted using an in-house questionnaire, as well as a qualitative assessment of the patients' medical records. The study population of 34 patients had a previous diagnosis of idiopathic VT or frequent PVCs from the RVOT, and received RFA treatment between 2002 and 2005. The main symptoms prior to RFA were palpitations (82.4%) and dizziness (76.5%). A reduction in symptoms following RFA was reported by 91.2% of patients (p < 0.001). Furthermore, there was a reduced use of antiarrhythmic medication after RFA (p < 0.001). General health perception classified on a scale of 1 (poor) to 4 (excellent), improved from median class 1 to 3 (p < 0.001) during long-term follow-up. The fitness to work increased from median class 3 to class 5 (1 = incapacitated, 5 = full time employment, p = 0.038), while the rate of patients in full time employment increased from 26.5% to 55.9% after RFA (p = 0.02). A reduction of symptoms and use of antiarrhythmic medication, as well as an improvement in the general health perception and fitness to work after RFA of idiopathic ventricular arrhythmias can be demonstrated at ten-year follow-up. Copyright © 2016 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.

Computerized mapping of fibrillation in normal ventricular myocardium

NASA Astrophysics Data System (ADS)

Chen, Peng-Sheng; Garfinkel, Alan; Weiss, James N.; Karagueuzian, Hrayr S.

1998-03-01

It is well known that the ability to fibrillate is intrinsic to a normal ventricle that exceeds a critical mass. The questions we address are how is ventricular fibrillation (VF) initiated and perpetuated in normal myocardium, and why is VF not seen more often in the general population if all ventricles have the ability to fibrillate. To study the mechanisms of VF, we used computerized mapping techniques with up to 512 channels of simultaneous multisite recordings for data acquisition. The data were then processed for dynamic display of the activation patterns and for mathematical analyses of the activation intervals. The results show that in normal ventricles, VF can be initiated by a single strong premature stimulus given during the vulnerable period of the cardiac cycle. The initial activations form a figure-eight pattern. Afterward, VF will perpetuate itself without any outside help. The self-perpetuation itself is due to at least two factors. One is that single wave fronts spontaneously break up into two or more wavelets. The second is that when two wavelets intersect perpendicular to each other, the second wavelet is broken by the residual refractoriness left over from the first wavelet. Mathematical analyses of the patterns of activation during VF revealed that VF is a form of chaos, and that transition from ventricular tachycardia (VT) to VF occurs via the quasiperiodic route. In separate experiments, we found that we can convert VF to VT by tissue size reduction. The physiological mechanism associated with the latter transition appears to be the reduction of the number of reentrant wave fronts and wandering wavelets. Based on these findings, we propose that the reentrant wave fronts and the wandering wavelets serve as the physiological equivalent of coupled oscillators. A minimal number of oscillators is needed for VF to perpetuate itself, and to generate chaotic dynamics; hence a critical mass is required to perpetuate VF. We conclude that VF in normal

Effects of Erythropoietin Administration on Adrenal Glands of Landrace/Large White Pigs after Ventricular Fibrillation.

PubMed

Faa, Armando; Faa, Gavino; Papalois, Apostolos; Obinu, Eleonora; Locci, Giorgia; Pais, Maria Elena; Lelovas, Pavlos; Barouxis, Dimitrios; Pantazopoulos, Charalampos; Vasileiou, Panagiotis V; Iacovidou, Nicoletta; Xanthos, Theodoros

2016-01-01

Aim. To evaluate the effects of erythropoietin administration on the adrenal glands in a swine model of ventricular fibrillation and resuscitation. Methods. Ventricular fibrillation was induced via pacing wire forwarded into the right ventricle in 20 female Landrace/Large White pigs, allocated into 2 groups: experimental group treated with bolus dose of erythropoietin (EPO) and control group which received normal saline. Cardiopulmonary resuscitation (CPR) was performed immediately after drug administration as per the 2010 European Resuscitation Council (ERC) guidelines for Advanced Life Support (ALS) until return of spontaneous circulation (ROSC) or death. Animals who achieved ROSC were monitored, mechanically ventilated, extubated, observed, and euthanized. At necroscopy, adrenal glands samples were formalin-fixed, paraffin-embedded, and routinely processed. Sections were stained with hematoxylin-eosin. Results. Oedema and apoptosis were the most frequent histological changes and were detected in all animals in the adrenal cortex and in the medulla. Mild and focal endothelial lesions were also detected. A marked interindividual variability in the degree of the intensity of apoptosis and oedema at cortical and medullary level was observed within groups. Comparing the two groups, higher levels of pathological changes were detected in the control group. No significant difference between the two groups was observed regarding the endothelial changes. Conclusions. In animals exposed to ventricular fibrillation, EPO treatment has protective effects on the adrenal gland.

Spatial resolution of pace mapping of idiopathic ventricular tachycardia/ectopy originating in the right ventricular outflow tract.

PubMed

Bogun, Frank; Taj, Majid; Ting, Michael; Kim, Hyungjin Myra; Reich, Stephen; Good, Eric; Jongnarangsin, Krit; Chugh, Aman; Pelosi, Frank; Oral, Hakan; Morady, Fred

2008-03-01

Pace mapping has been used to identify the site of origin of focal ventricular arrhythmias. The spatial resolution of pace mapping has not been adequately quantified using currently available three-dimensional mapping systems. The purpose of this study was to determine the spatial resolution of pace mapping in patients with idiopathic ventricular tachycardia or premature ventricular contractions originating in the right ventricular outflow tract. In 16 patients with idiopathic ventricular tachycardia/ectopy from the right ventricular outflow tract, comparisons and classifications of pace maps were performed by two observers (good pace map: match >10/12 leads; inadequate pace map: match < or =10/12 leads) and a customized MATLAB 6.0 program (assessing correlation coefficient and normalized root mean square of the difference (nRMSd) between test and template signals). With an electroanatomic mapping system, the correlation coefficient of each pace map was correlated with the distance between the pacing site and the effective ablation site. The endocardial area within the 10-ms activation isochrone was measured. The ablation procedure was effective in all patients. Sites with good pace maps had a higher correlation coefficient and lower nRMSd than sites with inadequate pace maps (correlation coefficient: 0.96 +/- 0.03 vs 0.76 +/- 0.18, P <.0001; nRMSd: 0.41 +/- 0.16 vs 0.89 +/- 0.39, P <.0001). Using receiver operating characteristic curves, appropriate cutoff values were >0.94 for correlation coefficient (sensitivity 81%, specificity 89%) and < or =0.54 for nRMSd (sensitivity 76%, specificity 80%). Good pace maps were located a mean of 7.3 +/- 5.0 mm from the effective ablation site and had a mean activation time of -24 +/- 7 ms. However, in 3 (18%) of 16 patients, the best pace map was inadequate at the effective ablation site, with an endocardial activation time at these sites of -25 +/- 12 ms. Pace maps with correlation coefficient > or =0.94 were confined to an

Ventricular fibrillation caused by electrocoagulation in monopolar mode during laparoscopic subphrenic mass resection

PubMed Central

Yan, Chun-Yan; Wang, Yi-Fan; Yu, Hong

2010-01-01

Background Monopolar is usually a safe and effective electrosurgical unit used in laparoscopic general surgery. However, it can cause adverse outcomes and even cardiac arrest. We present a video of laparoscopic subphrenic mass resection using monopolar coagulation during which ventricular fibrillation occurred and from which the patient was successfully resuscitated. Methods Our patient was a 39-year-old man who was admitted to our institution for treatment of a liver mass. The mass was located in the left subphrenic region and was 3.31 cm × 2.7 cm according to B ultrasound. He had had a spleen resection after a car accident 14 years before. He was otherwise healthy and a physical examination was negative. He was scheduled for “laparoscopic exploration, mass resection.” General anesthesia was induced and the operation began. While dissecting the mass from the diaphragm there was some bleeding; monopolar electrocoagulation with 68 W was performed upon which ventricular fibrillation occurred. The operation was stopped and closed-chest compression began immediately. Defibrillation (200-J shock) was performed in 1 min and rhythm returned to sinus. Results The operation was resumed carefully and uneventfully. The patient was sent to the postoperative acute care unit and was extubated 10 min after operation. The patient recovered uneventfully without any signs of permanent cardiac injury and was discharged on postoperative day 3. The final pathology was accessory spleen. Conclusions We present a video of a patient who experienced ventricular fibrillation during laparoscopic surgery which was successfully defibrillated leaving no permanent cardiac injury. We assume the reason for the ventricular fibrillation was the low-frequency leakage current from electrocoagulation which may be conducted by Swan-Ganz catheter to the heart. It is important that we be familiar with the character of electrosurgical unit when performing laparoscopic surgery. We should be

Prevalence and prognosis of ventricular tachycardia/ventricular fibrillation in patients with post-infarction left ventricular aneurysm: Analysis of 575 cases.

PubMed

Ning, Xiaohui; Ye, Xuerui; Si, Yanhua; Yang, Zihe; Zhao, Yunzi; Sun, Qi; Chen, Ruohan; Tang, Min; Chen, Keping; Zhang, Xiaoli; Zhang, Shu

2018-03-21

We investigated the prevalence of ventricular tachycardia/ventricular fibrillation (VT/VF) in Post-infarction left ventricular aneurysm (PI-LVA) patients and analyze clinical outcomes in patients presenting with VT/VF. 575 PI-LVA patients were enrolled and investigated by logistic regression analysis. Patients with VT/VF were followed up, the composite primary endpoint was cardiac death and appropriate ICD/external shocks. The incidence of sustained VT/VF was 11%. Logistical regression analysis showed male gender, enlarged LV end diastolic diameter (LVEDD) and higher NYHA class were correlated with VT/VF development. During follow up of 46 ± 15 months, 19 out of 62(31%) patients reached study end point. Multivariate Cox regression analysis revealed that enlarged LVEDD and moderate/severe mitral regurgitation (MR) were independently predictive of clinical outcome. Male gender, enlarged LVEDD and higher NYHA class associated with risk of sustained VT/VF in PI-LVA patients. Among VT/VF positive patients, enlarged LVEDD and moderate/severe MR independently predicted poor clinical prognosis. Copyright © 2018. Published by Elsevier Inc.

Atrial and ventricular function after cardioversion of atrial fibrillation.

PubMed Central

Xiong, C.; Sonnhag, C.; Nylander, E.; Wranne, B.

1995-01-01

OBJECTIVE--Previous studies on atrial recovery after cardioversion of atrial fibrillation have not taken into account new knowledge about the pathophysiology of transmitral and transtricuspid flow velocity patterns. It is possible to shed further light on this problem if atrioventricular inflow velocity, venous filling pattern, and atrioventricular annulus motion are recorded and interpreted together. DESIGN--Prospective examinations of mitral and tricuspid transvalvar flow velocities, superior caval and pulmonary venous filling, and mitral and tricuspid annulus motion were recorded using Doppler echocardiography. Examinations were performed before and 24 hours, 1 month, and 20 months after cardioversion. SETTING--Tertiary referral centre for cardiac disease with facilities for invasive and non-invasive investigation. PATIENTS--16 patients undergoing cardioversion of atrial fibrillation in whom sinus rhythm had persisted for 24 hours or more. RESULTS--Before conversion there was no identifiable A wave in transvalvar flow recordings. The total motion of the tricuspid and mitral annulus was subnormal and there was no identifiable atrial component. Venous flow patterns in general showed a low systolic velocity. After conversion, A waves and atrial components were seen in all patients and increased significantly (P < 0.01) with time. There was a similar time course for the amplitude of annulus atrial components, an increased systolic component of venous inflow, an increased A wave velocity, and a decreased E/A ratio of the transvalvar velocity curves. The ventricular component of annulus motion was unchanged. Changes in general occurred earlier on the right side than the left. CONCLUSIONS--This study indicates that, in addition to the previously known electromechanical dissociation of atrial recovery that exists after cardioversion of atrial fibrillation, there may also be a transient deterioration of ventricular function modulating the transvalvar inflow velocity

Management of Arrhythmias in Athletes: Atrial Fibrillation, Premature Ventricular Contractions, and Ventricular Tachycardia.

PubMed

Lai, Ernest; Chung, Eugene H

2017-10-09

Management of atrial fibrillation, premature ventricular contractions, and ventricular tachycardia without underlying cardiac disease or arrhythmogenic conditions differs in athletes from the general population. Athletes tend to be younger, healthier individuals with few comorbidities. Therapies that work well in the general population may not be appropriate or preferable for athletes. Management strategies include deconditioning, pharmacologic therapy, such as rate control with β-blockers or non-dihydropyridine calcium channel blockers and rhythm control with class I or class III antiarrhythmic drugs, and catheter ablation. Deconditioning is not preferred by athletes because of lost playing time. Pharmacologic therapy is well tolerated among most individuals, but is not as favorable in athletes. Rate control medications can reduce performance and β-blockers, in particular, are prohibited in many sports. Antiarrhythmic drugs are preferred over rate control with athletes, but many, especially younger athletes, may not like the idea of long-term medical therapy. Catheter ablation has been proven to be safe and efficacious, may eliminate the need for long-term medical therapy, and is supported by the major societies (AHA, ACC, ESC).

Accurate recognition and effective treatment of ventricular fibrillation by automated external defibrillators in adolescents.

PubMed

Atkins, D L; Hartley, L L; York, D K

1998-03-01

To evaluate the accuracy and efficacy of automated external defibrillators (AEDs) in patients <16 years old. AEDs are standard therapy in out-of-hospital resuscitation of adults and have led to higher success rates. Their use in children and adolescents has never been evaluated, despite recommendations from the American Heart Association that they be used in children >8 years of age. This was a retrospective cohort study of children <16 years old who underwent out-of-hospital cardiac resuscitation and on whom an AED was used during the resuscitation. The setting was rural and urban prehospital emergency medical systems. Patients were identified by review of a database of cardiac arrests maintained by a large surveillance program of these services. AEDs were used to assess cardiac rhythm in 18 patients with a mean age of 12.1 +/- 3.7 years. The cardiac rhythms were analyzed 67 times and included ventricular fibrillation (25), asystole/pulseless electrical activity (32), sinus bradycardia (6), and sinus tachycardia (4). The AEDs recognized all nonshockable rhythms accurately and advised no shock. Ventricular fibrillation was recognized accurately in 22 (88%) of 25 episodes and advised or administered a shock 22 times. Sensitivity and specificity for accurate rhythm analysis were 88% and 100%, respectively. One patient with a nonshockable rhythm survived, whereas 3 of 9 patients with ventricular fibrillation survived. These data furnish evidence that AEDs provide accurate rhythm detection and shock delivery to children and young adolescents. AED use is potentially as effective for children as it is for adults.

Unusual cause of exercise-induced ventricular fibrillation in a well-trained adult endurance athlete: a case report.

PubMed

Vogt, Stefan; Koenig, Daniel; Prettin, Stephan; Pottgiesser, Torben; Allgeier, Juergen; Dickhuth, Hans-Hermann; Hirschmueller, Anja

2008-04-23

The diseases responsible for sudden deaths in athletes differ considerably with regard to age. In young athletes, congenital malformations of the heart and/or vascular system cause the majority of deaths and can only be detected noninvasively by complex diagnostics. In contrast, in older athletes who die suddenly, atherosclerotic disease of the coronary arteries is mostly found. Reports of congenital coronary anomalies as a cause of sudden death in older athletes are rare. A 48-year-old man who was a well-trained, long-distance runner collapsed at the finish of a half marathon because of a myocardial infarction with ventricular fibrillation. Coronary angiography showed an anomalous origin of the right coronary artery from the left sinus of Valsalva with minimal wall alterations. Multislice computed tomography of the coronary arteries confirmed these findings. Cardiomagnetic resonance imaging demonstrated a mild hypokinesia of the basal right- and left-ventricular posterior wall. An electrophysiological study showed an inducible temporary polymorphic ventricular tachycardia and an inducible ventricular fibrillation. The athlete was subsequently treated by acetylsalicylic acid 100 mg (0-1-0), bisoprolol 2.5 mg (1-0-0) and atorvastatin 10 mg (0-0-1) and was instructed to keep his training intensity under the 'individual anaerobic threshold'. Intense and long-lasting exercise under extreme environmental conditions, particularly heat, should also be avoided. This case report presents a coronary anomaly as the most likely reason for an exercise-induced myocardial infarction with ventricular fibrillation in a well-trained 48-year-old endurance athlete. Therefore, coronary anomalies have also to be considered as a possible cause of cardiac problems in older athletes.

Double simultaneous defibrillators for refractory ventricular fibrillation.

PubMed

Leacock, Benjamin W

2014-04-01

Out-of-hospital cardiac arrest is a leading cause of death in the United States. Ventricular fibrillation (VF) is the most common initial rhythm after cardiac arrest. To describe a novel approach to the patient with intractable VF after cardiac arrest. A 51-year old man presented in cardiac arrest after a ST-elevation myocardial infarction. He remained in VF despite receiving typical therapy including cardiopulmonary resuscitation, amiodarone, lidocaine, epinephrine, and five attempts at defibrillation with 200 J using a biphasic defibrillator. VF was eventually terminated with 400 J by the simultaneous use of two biphasic defibrillators. The patient had a full recovery. We present a case and supportive literature for a novel treatment of high-energy defibrillation in a patient with refractory VF. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of left ventricular diastolic dysfunction on left atrial appendage function and thrombotic potential in nonvalvular atrial fibrillation.

PubMed

Demirçelik, Muhammed Bora; Çetin, Mustafa; Çiçekcioğlu, Hülya; Uçar, Özgül; Duran, Mustafa

2014-05-01

We aimed to investigate effects of left ventricular diastolic dysfunction on left atrial appendage functions, spontaneous echo contrast and thrombus formation in patients with nonvalvular atrial fibrillation. In 58 patients with chronic nonvalvular atrial fibrilation and preserved left ventricular systolic function, left atrial appendage functions, left atrial spontaneous echo contrast grading and left ventricular diastolic functions were evaluated using transthoracic and transoesophageal echocardiogram. Patients divided in two groups: Group D (n=30): Patients with diastolic dysfunction, Group N (n=28): Patients without diastolic dysfunction. Categorical variables in two groups were evaluated with Pearson's chi-square or Fisher's exact test. The significance of the lineer correlation between the degree of spontaneous echo contrast (SEC) and clinical measurements was evaluated with Spearman's correlation analysis. Peak pulmonary vein D velocity of the Group D was significantly higher than the Group N (p=0.006). However, left atrial appendage emptying velocity, left atrial appendage lateral wall velocity, peak pulmonary vein S, pulmonary vein S/D ratio were found to be significantly lower in Group D (p=0.028, p<0.001, p<0.001; p<0.001). Statistically significant negative correlation was found between SEC in left atrium and left atrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities respectively (r=-0.438, r=-0.328, r=-0.233, r=-0.447). Left atrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities were significantly lower in SEC 2-3-4 than SEC 1 (p=0.003, p=0.029, p<0.001, p=0.002). In patients with nonvalvular atrial fibrillation and preserved left ventricular ejection fraction, left atrial appendage functions are decreased in patients with left ventricular diastolic dysfunction. Left ventricular diastolic dysfunction may constitute a potential risk for formation of thrombus and stroke.

Idiopathic ventricular outflow tract arrhythmias from the great cardiac vein: challenges and risks of catheter ablation.

PubMed

Steven, D; Pott, C; Bittner, A; Sultan, A; Wasmer, K; Hoffmann, B A; Köbe, J; Drewitz, I; Milberg, P; Lueker, J; Mönnig, G; Servatius, H; Willems, S; Eckardt, L

2013-11-20

Catheter ablation for idiopathic ventricular arrhythmia is well established but epicardial origin, proximity to coronary arteries, and limited accessibility may complicate ablation from the venous system in particular from the great cardiac vein (GCV). Between April 2009 and October 2010 14 patients (56 ± 15 years; 9 male) out of a total group of 117 patients with idiopathic outflow tract tachycardias were included undergoing ablation for idiopathic VT or premature ventricular contractions (PVC) originating from GCV. All patients in whom the PVC arose from the GCV were subject to the study. In these patients angiography of the left coronary system was performed with the ablation catheter at the site of earliest activation. Successful ablation was performed in 6/14 (43%) and long-term success was achieved in 5/14 (36%) patients. In 4/14 patients (28.6%) ablation was not performed. In another 4 patients (26.7%), ablation did not abolish the PVC/VT. In the majority, the anatomical proximity to the left coronary system prohibited effective RF application. In 3 patients RF application resulted in a coronary spasm with complete regression as revealed in repeat coronary angiography. A relevant proportion idiopathic VT/PVC can safely be ablated from the GCV without significant permanent coronary artery stenosis after RF application. Our data furthermore demonstrate that damage to the coronary artery system is likely to be transient. © 2013.

Reasons for failed ablation for idiopathic right ventricular outflow tract-like ventricular arrhythmias.

PubMed

Yokokawa, Miki; Good, Eric; Crawford, Thomas; Chugh, Aman; Pelosi, Frank; Latchamsetty, Rakesh; Jongnarangsin, Krit; Ghanbari, Hamid; Oral, Hakan; Morady, Fred; Bogun, Frank

2013-08-01

The right ventricular outflow tract (RVOT) is the most common site of origin of ventricular arrhythmias (VAs) in patients with idiopathic VAs. A left bundle branch block, inferior axis morphology arrhythmia is the hallmark of RVOT arrhythmias. VAs from other sites of origin can mimic RVOT VAs, and ablation in the RVOT typically fails for these VAs. To analyze reasons for failed ablations of RVOT-like VAs. Among a consecutive series of 197 patients with an RVOT-like electrocardiographic (ECG) morphology who were referred for ablation, 38 patients (13 men; age 46 ± 14 years; left ventricular ejection fraction 47% ± 14%) in whom a prior procedure failed within the RVOT underwent a second ablation procedure. ECG characteristics of the VA were compared to a consecutive series of 50 patients with RVOT VAs. The origin of the VA was identified in 95% of the patients. In 28 of 38 (74%) patients, the arrhythmia origin was not in the RVOT. The VA originated from intramural sites (n = 8, 21%), the pulmonary arteries (n = 7, 18%), the aortic cusps (n = 6, 16%), and the epicardium (n = 5, 13%). The origin was within the RVOT in 10 (26%) patients. In 2 (5%) patients, the origin could not be identified despite biventricular, aortic, and epicardial mapping. The VA was eliminated in 34 of 38 (89%) patients with repeat procedures. The ECG features of patients with failed RVOT-like arrhythmias were different from the characteristics of RVOT arrhythmias. In patients in whom ablation of a VA with an RVOT-like appearance fails, mapping of the pulmonary artery, the aortic cusps, the epicardium, the left ventricular outflow tract, and the aortic cusps will help identify the correct site of origin. The 12-lead ECG is helpful in differentiating these VAs from RVOT VAs. Copyright © 2013 Heart Rhythm Society. All rights reserved.

Quasiperiodicity and chaos in cardiac fibrillation.

PubMed

Garfinkel, A; Chen, P S; Walter, D O; Karagueuzian, H S; Kogan, B; Evans, S J; Karpoukhin, M; Hwang, C; Uchida, T; Gotoh, M; Nwasokwa, O; Sager, P; Weiss, J N

1997-01-15

In cardiac fibrillation, disorganized waves of electrical activity meander through the heart, and coherent contractile function is lost. We studied fibrillation in three stationary forms: in human chronic atrial fibrillation, in a stabilized form of canine ventricular fibrillation, and in fibrillation-like activity in thin sheets of canine and human ventricular tissue in vitro. We also created a computer model of fibrillation. In all four studies, evidence indicated that fibrillation arose through a quasiperiodic stage of period and amplitude modulation, thus exemplifying the "quasiperiodic transition to chaos" first suggested by Ruelle and Takens. This suggests that fibrillation is a form of spatio-temporal chaos, a finding that implies new therapeutic approaches.

Quasiperiodicity and chaos in cardiac fibrillation.

PubMed Central

Garfinkel, A; Chen, P S; Walter, D O; Karagueuzian, H S; Kogan, B; Evans, S J; Karpoukhin, M; Hwang, C; Uchida, T; Gotoh, M; Nwasokwa, O; Sager, P; Weiss, J N

1997-01-01

In cardiac fibrillation, disorganized waves of electrical activity meander through the heart, and coherent contractile function is lost. We studied fibrillation in three stationary forms: in human chronic atrial fibrillation, in a stabilized form of canine ventricular fibrillation, and in fibrillation-like activity in thin sheets of canine and human ventricular tissue in vitro. We also created a computer model of fibrillation. In all four studies, evidence indicated that fibrillation arose through a quasiperiodic stage of period and amplitude modulation, thus exemplifying the "quasiperiodic transition to chaos" first suggested by Ruelle and Takens. This suggests that fibrillation is a form of spatio-temporal chaos, a finding that implies new therapeutic approaches. PMID:9005999

Idiopathic annular dilation: a rare cause of isolated severe tricuspid regurgitation.

PubMed

Girard, S E; Nishimura, R A; Warnes, C A; Dearani, J A; Puga, F J

2000-03-01

The management of patients with severe tricuspid regurgitation (TR) requires the clinician to clarify the mechanism of regurgitation. Primary disorders of the tricuspid valve, either congenital or acquired, may be readily identified by echocardiography. Severe TR most often results from left-sided heart disease and secondary pulmonary hypertension. Cardiomyopathic processes may also cause right ventricular failure and functional TR. We report three patients with severe TR due to idiopathic annular dilation. The tricuspid valves were otherwise normal on surgical inspection, and the pulmonary pressures were not significantly elevated. Each patient was aged over 65 years and had chronic atrial fibrillation with preserved left ventricular systolic function. Surgical treatment was associated with marked clinical improvement. Clinicians should recognize this unusual but treatable cause of right-sided congestive heart failure.

Ventricular fibrillation occurring after atrioventricular node ablation despite minimal difference between pre- and post-ablation heart rates.

PubMed

Squara, F; Theodore, G; Scarlatti, D; Ferrari, E

2017-02-01

We report the case of an 82-year-old man presenting with ventricular fibrillation (VF) occurring acutely after atrioventricular node (AVN) ablation. This patient had severe valvular cardiomyopathy, chronic atrial fibrillation (AF), and underwent prior to the AVN ablation a biventricular implantable cardiac defibrillator positioning. The VF was successfully cardioverted with one external electrical shock. What makes this presentation original is that the pre-ablation spontaneous heart rate in AF was slow (84 bpm), and that VF occurred after ablation despite a minimal heart rate drop of only 14 bpm. VF is the most feared complication of AVN ablation, but it had previously only been described in case of acute heart rate drop after ablation of at least 30 bpm (and more frequently>50 bpm). This case report highlights the fact that VF may occur after AVN ablation regardless of the heart rate drop, rendering temporary fast ventricular pacing mandatory whatever the pre-ablation heart rate. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Sudden cardiac arrest following ventricular fibrillation attributed to anabolic steroid use in an adolescent.

PubMed

Lichtenfeld, Jana; Deal, Barbara J; Crawford, Susan

2016-06-01

Anabolic androgenic steroids are synthetic derivatives of testosterone that promote the growth of skeletal muscles and have many recognised cardiovascular effects. We report the clinical presentation and pathological findings of an adolescent male whose sudden cardiac arrest following ventricular fibrillation was attributed to anabolic androgenic steroid use. The age of our patient reflects the usage of anabolic androgenic steroids among younger athletes and highlights the need for increased awareness among practitioners.

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.

Ventricular fibrillation associated with early repolarization in a patient with thyroid storm.

PubMed

Ueno, Akira; Yamamoto, Takeshi; Sato, Naoki; Tanaka, Keiji

2010-11-01

We present a case of a 69-year-old male who was hospitalized for the treatment of thyroid storm due to Grave's disease, who presented with unexpected ventricular fibrillation (VF). The possible etiology was early repolarization (ER), characterized by J-point elevation in inferior and posterolateral leads, unmasked by the attenuation of beta-adrenergic effect with normalization of thyroid hormones and following the administration of a beta-blocker. Our case focuses attention on the occurrence of VF in a patient with ER during the treatment of hyperthyroidism, which to our knowledge is the first such report.

Catheter ablation of fatal ventricular tachyarrhythmias storm in acute coronary syndrome--role of Purkinje fiber network.

PubMed

Enjoji, Yoshihisa; Mizobuchi, Masahiro; Muranishi, Hiromi; Miyamoto, Chinae; Utsunomiya, Makoto; Funatsu, Atsushi; Kobayashi, Tomoko; Nakamura, Shigeru

2009-12-01

Ventricular fibrillation (VF) or ventricular tachycardia (VT) storm is a life-threatening arrhythmia. Antiarrhythmic drugs (AADs) are not necessarily effective to rescue life from such conditions. Catheter ablation (CA) targeting triggering premature ventricular contractions (PVCs) of VF or VT that originates from Purkinje fiber network (PFN) is reported to be effective, especially in idiopathic patients. However, in condition of acute coronary syndrome (ACS), the efficacy of CA is not well understood. To clarify the usefulness of CA as an alternative way to AADs, we performed CA in four patients with VF or VT storm. The Purkinje potential was seen just before the myocardial ventricular wave during sinus rhythm that became more prominent and double components during the initiating PVC at the targeted area. Following CA, spontaneous episodes of VF or VT were no longer observed. CA is an efficacious way to bail out PFN-related VF or VT storm even in ACS.

Comparison of remote magnetic navigation ablation and manual ablation of idiopathic ventricular arrhythmia after failed manual ablation.

PubMed

Kawamura, Mitsuharu; Scheinman, Melvin M; Tseng, Zian H; Lee, Byron K; Marcus, Gregory M; Badhwar, Nitish

2017-01-01

Catheter ablation for idiopathic ventricular arrhythmia (VA) is effective and safe, but efficacy is frequently limited due to an epicardial origin and difficult anatomy. The remote magnetic navigation (RMN) catheter has a flexible catheter design allowing access to difficult anatomy. We describe the efficacy of the RMN for ablation of idiopathic VA after failed manual ablation. Among 235 patients with idiopathic VA referred for catheter ablation, we identified 51 patients who were referred for repeat ablation after a failed manual ablation. We analyzed the clinical characteristics, including the successful ablation site and findings at electrophysiology study, in repeat procedures conducted using RMN as compared with manual ablation. Among these patients, 22 (43 %) underwent repeat ablation with the RMN and 29 (57 %) underwent repeat ablation with a manual ablation. Overall, successful ablation rate was significantly higher using RMN as compared with manual ablation (91 vs. 69 %, P = 0.02). Fluoroscopy time in the RMN was 17 ± 12 min as compared with 43 ± 18 min in the manual ablation (P = 0.009). Successful ablation rate in the posterior right ventricular outflow tract (RVOT) plus posterior-tricuspid annulus was higher with RMN as compared with manual ablation (92 vs. 50 %, P = 0.03). Neither groups exhibited any major complications. The RMN is more effective in selected patients with recurrent idiopathic VA after failed manual ablation and is associated with less fluoroscopy time. The RMN catheters have a flexible design enabling them to access otherwise difficult anatomy including the posterior tricuspid annulus and posterior RVOT.

Influence of Genotype on Structural Atrial Abnormalities and Atrial Fibrillation or Flutter in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

PubMed

Bourfiss, Mimount; Te Riele, Anneline S J M; Mast, Thomas P; Cramer, Maarten J; VAN DER Heijden, Jeroen F; VAN Veen, Toon A B; Loh, Peter; Dooijes, Dennis; Hauer, Richard N W; Velthuis, Birgitta K

2016-12-01

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is associated with desmosomal mutations. Although desmosomal disruption affects both ventricles and atria, little is known about atrial involvement in ARVD/C. To describe the extent and clinical significance of structural atrial involvement and atrial arrhythmias (AA) in ARVD/C stratified by genotype. We included 71 patients who met ARVD/C Task Force Criteria and underwent cardiac magnetic resonance (CMR) imaging and molecular genetic analysis. Indexed atrial end-diastolic volume and area-length-ejection-fraction (ALEF) were evaluated on CMR and compared to controls with idiopathic right ventricular outflow tract tachycardia (n = 40). The primary outcome was occurrence of AA (atrial fibrillation or atrial flutter) during follow-up, recorded by 12-lead ECG, Holter monitoring or implantable cardioverter defibrillator (ICD) interrogation. Patients harbored a desmosomal plakophilin-2 (PKP2) (n = 37) or nondesmosomal phospholamban (PLN) (n = 14) mutation. In 20 subjects, no pathogenic mutation was identified. Compared to controls, right atrial (RA) volumes were reduced in PKP2 (P = 0.002) and comparable in PLN (P = 0.441) mutation carriers. In patients with no mutation identified, RA (P = 0.011) and left atrial (P = 0.034) volumes were increased. Bi-atrial ALEF showed no significant difference between the groups. AA were experienced by 27% of patients and occurred equally among PKP2 (30%) and no mutation identified patients (30%), but less among PLN mutation carriers (14%). Genotype influences atrial volume and occurrence of AA in ARVD/C. While the incidence of AA is similar in PKP2 mutation carriers and patients with no mutation identified, PKP2 mutation carriers have significantly smaller atria. This suggests a different arrhythmogenic mechanism. © 2016 Wiley Periodicals, Inc.

Attenuating the defibrillation dosage decreases postresuscitation myocardial dysfunction in a swine model of pediatric ventricular fibrillation

PubMed Central

Berg, Marc D.; Banville, Isabelle L.; Chapman, Fred W.; Walker, Robert G.; Gaballa, Mohammed A.; Hilwig, Ronald W.; Samson, Ricardo A.; Kern, Karl B.; Berg, Robert A.

2009-01-01

Objective The optimal biphasic defibrillation dose for children is unknown. Postresuscitation myocardial dysfunction is common and may be worsened by higher defibrillation doses. Adult-dose automated external defibrillators are commonly available; pediatric doses can be delivered by attenuating the adult defibrillation dose through a pediatric pads/cable system. The objective was to investigate whether unattenuated (adult) dose biphasic defibrillation results in greater postresuscitation myocardial dysfunction and damage than attenuated (pediatric) defibrillation. Design Laboratory animal experiment. Setting University animal laboratory. Subjects Domestic swine weighing 19 ± 3.6 kg. Interventions Fifty-two piglets were randomized to receive biphasic defibrillation using either adult-dose shocks of 200, 300, and 360 J or pediatric-dose shocks of ~50, 75, and 85 J after 7 mins of untreated ventricular fibrillation. Contrast left ventriculograms were obtained at baseline and then at 1, 2, 3, and 4 hrs postresuscitation. Postresuscitation left ventricular ejection fraction and cardiac troponins were evaluated. Measurements and Main Results By design, piglets in the adult-dose group received shocks with more energy (261 ± 65 J vs. 72 ± 12 J, p < .001) and higher peak current (37 ± 8 A vs. 13 ± 2 A, p < .001) at the largest defibrillation dose needed. In both groups, left ventricular ejection fraction was reduced significantly at 1, 2, and 4 hrs from baseline and improved during the 4 hrs postresuscitation. The decrease in left ventricular ejection fraction from baseline was greater after adult-dose defibrillation. Plasma cardiac troponin levels were elevated 4 hrs postresuscitation in 11 of 19 adult-dose piglets vs. four of 20 pediatric-dose piglets (p = .02). Conclusions Unattenuated adult-dose defibrillation results in a greater frequency of myocardial damage and worse postresuscitation myocardial function than pediatric doses in a swine model of prolonged out

Anatomic Guidance For Ablation: Atrial Flutter, Fibrillation, and Outflow Tract Ventricular Tachycardia

PubMed Central

Sehar, Nandini; Mears, Jennifer; Bisco, Susan; Patel, Sandeep; Lachman, Nirusha; Asirvatham, Samuel J

2010-01-01

After initial documentation of excellent efficacy with radiofrequency ablation, this procedure is being performed increasingly in more complex situations and for more difficult arrhythmia. In these circumstances, an accurate knowledge of the anatomic basis for the ablation procedure will help maintain this efficacy and improve safety. In this review, we discuss the relevant anatomy for electrophysiology interventions for typical right atrial flutter, atrial fibrillation, and outflow tract ventricular tachycardia. In the pediatric population, maintaining safety is a greater challenge, and here again, knowing the neighboring and regional anatomy of the arrhythmogenic substrate for these arrhythmias may go a long way in preventing complications. PMID:20811537

Ventricular arrhythmias in the absence of structural heart disease.

PubMed

Prystowsky, Eric N; Padanilam, Benzy J; Joshi, Sandeep; Fogel, Richard I

2012-05-15

Ventricular arrhythmia (VA) in structurally normal hearts can be broadly considered under non-life-threatening monomorphic and life-threatening polymorphic rhythms. Monomorphic VA is classified on the basis of site of origin in the heart, and the most common areas are the ventricular outflow tracts and left ventricular fascicles. The morphology of the QRS complexes on electrocardiogram is an excellent tool to identify the site of origin of the rhythm. Although these arrhythmias are common and generally carry an excellent prognosis, rare sudden death events have been reported. Very frequent ventricular ectopy may also result in a cardiomyopathy in a minority of patients. Suppression of VA may be achieved using calcium-channel blockers, beta-adrenergic blockers, and class I or III antiarrhythmic drugs. Radiofrequency ablation has emerged as an excellent option to eliminate these arrhythmias, although certain foci including aortic cusps and epicardium may be technically challenging. Polymorphic ventricular tachycardia (VT) is rare and generally occurs in patients with genetic ion channel disorders including long QT syndrome, Brugada syndrome, catecholaminergic polymorphic VT, and short QT syndrome. Unlike monomorphic VT, these arrhythmic syndromes are associated with sudden death. While the cardiac gross morphology is normal, suggesting a structurally normal heart, abnormalities exist at the molecular level and predispose them to arrhythmias. Another fascinating area, idiopathic ventricular fibrillation and early repolarization syndrome, are undergoing research for a genetic basis. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

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.

Maintenance of ventricular fibrillation in heterogeneous ventricle.

PubMed

Arevalo, Hamenegild J; Trayanova, Natalia A

2006-01-01

Although ventricular fibrillation (VF) is the prevalent cause of sudden cardiac death, the mechanisms that underlie VF remain elusive. One possible explanation is that VF is driven by a single robust rotor that is the source of wavefronts that break-up due to functional heterogeneities. Previous 2D computer simulations have proposed that a heterogeneity in background potassium current (IK1) can serve as the substrate for the formation of mother rotor activity. This study incorporates IK1 heterogeneity between the left and right ventricle in a realistic 3D rabbit ventricle model to examine its effects on the organization of VF. Computer simulations show that the IK1 heterogeneity contributes to the initiation and maintenance of VF by providing regions of different refractoriness which serves as sites of wave break and rotor formation. A single rotor that drives the fibrillatory activity in the ventricle is not found in this study. Instead, multiple sites of reentry are recorded throughout the ventricle. Calculation of dominant frequencies for each myocardial node yields no significant difference between the dominant frequency of the LV and the RV. The 3D computer simulations suggest that IK1 spatial heterogeneity alone can not lead to the formation of a stable rotor.

Burst stimulation improves hemodynamics during resuscitation after prolonged ventricular fibrillation.

PubMed

Walcott, Gregory; Melnick, Sharon; Killingsworth, Cheryl; Ideker, Raymond

2009-02-01

Although return of spontaneous circulation (ROSC) is frequently achieved during resuscitation for sudden cardiac arrest, systolic blood pressure can then decrease, requiring additional myocardial support. Previous studies have shown that a series of 1-ms electrical pulses delivered through the defibrillation patches during ventricular fibrillation (VF) can stimulate the autonomic nervous system to increase myocardial function following defibrillation. We hypothesized that a similar series of electrical pulses could increase myocardial function and blood pressure during the early post-resuscitation period. Six swine were studied that underwent 6-7 min. Each animal received 5, 10, 15, or 20 pulse packets consisting of 6 10 A, 1-ms pulses every 3-4 s in random order whenever systolic blood pressure became less than 50 mmHg. All four sets of pulse packets were delivered to each animal. Systolic blood pressure and cardiac function (left ventricular +dP/dt) were increased to pre-stimulation levels or above by all four sets of pulse packets. The increases were significantly greater for the longer than the shorter number of pulse packets. The mean+/-SD duration of the time that the systolic pressure remained above 50 mmHg following pulse delivery was 4.2+/-2.5 min. Electrical stimulation during regular rhythm following prolonged VF and resuscitation can increase blood pressure and cardiac function to above prestimulation levels.

Comparison of low-energy versus high-energy biphasic defibrillation shocks following prolonged ventricular fibrillation.

PubMed

Walcott, Gregory P; Melnick, Sharon B; Killingsworth, Cheryl R; Ideker, Raymond E

2010-01-01

Since the initial development of the defibrillator, there has been concern that, while delivery of a large electric shock would stop fibrillation, it would also cause damage to the heart. This concern has been raised again with the development of the biphasic defibrillator. To compare defibrillation efficacy, postshock cardiac function, and troponin I levels following 150-J and 360-J shocks. Nineteen swine were anesthetized with isoflurane and instrumented with pressure catheters in the left ventricle, aorta, and right atrium. The animals were fibrillated for 6 minutes, followed by defibrillation with either low-energy (n = 8) or high-energy (n = 11) shocks. After defibrillation, chest compressions were initiated and continued until return of spontaneous circulation (ROSC). Epinephrine, 0.01 mg/kg every 3 minutes, was given for arterial blood pressure < 50 mmHg. Hemodynamic parameters were recorded for four hours. Transthoracic echocardiography was performed and troponin I levels were measured at baseline and four hours following ventricular fibrillation (VF). Survival rates at four hours were not different between the two groups (low-energy, 5 of 8; high-energy, 7 of 11). Results for arterial blood pressure, positive dP/dt (first derivative of pressure measured over time, a measure of left ventricular contractility), and negative dP/dt at the time of lowest arterial blood pressure (ABP) following ROSC were not different between the two groups (p = not significant [NS]), but were lower than at baseline. All hemodynamic measures returned to baseline by four hours. Ejection fractions, stroke volumes, and cardiac outputs were not different between the two groups at four hours. Troponin I levels at four hours were not different between the two groups (12 +/- 11 ng/mL versus 21 +/- 26 ng/mL, p = NS) but were higher at four hours than at baseline (19 +/- 19 ng/mL versus 0.8 +/- 0.5 ng/mL, p < 0.05, groups combined). Biphasic 360-J shocks do not cause more cardiac damage

Emergency catheter ablation in critical patients

PubMed Central

Tebbenjohanns, Jürgen; Rühmkorf, Klaus

2010-01-01

Emergency catheter ablation is justified in critical patients with drug-refractory life-threatening arrhythmias. The procedure can be used for ablation of an accessory pathway in preexcitation syndrome with high risk of ventricular fibrillation and in patients with shock due to ischemic cardiomyopathy and incessant ventricular tachycardia. Emergency catheter ablation can also be justified in patients with an electrical storm of the implanted cardioverter-defibrillator or in patients with idiopathic ventricular fibrillation. PMID:20606793

Evaluation ofserum free carnitine/acylcarnitine levels and left ventricular systolic functions in children with idiopathic epilepsy receiving valproic acid.

PubMed

Kulhas Celik, Ilknur; Tasdemir, Haydar Ali; Ince, Hülya; Celik, Halil; Sungur, Metin

2018-07-01

In the study, the effect of valproic acid on serum free/acylcarnitine levels and left ventricular systolic function in pediatric patients with idiopathic epilepsy receiving valproic acid was investigated. Patients receiving valproic acid treatment for six months between January 2012 and December 2012 were evaluated. Blood samples were obtained from the participants twice (pretreatment and the sixth month of treatment) and serum-free and acylcarnitine levels (from C2 to C18:1-OH) were measured using tandem mass spectrometry. Cardiac functions (ejection fraction, shortening fraction, cardiac output, left ventricular systolic and diastolic diameters, left atrial diameter, aortic diameter, cardiac output, and myocardial performance index) were evaluated by echocardiography simultaneously. A total of fourty patients, 23 female (57.5%) and 17 male (42.5%), with the diagnosis of idiopathic epilepsy and receiving valproic acid monotherapy were studied. Comparison of serum-free and acylcarnitine levels measured pretreatment and sixth month of treatment revealed a decrease in average C0 and C5:1 (respectively p < 0.001, p = 0.013) and an increase in C2, C3, C5-OH, C8:1 and C4-DC levels (respectively p < 0.001, p < 0.001, p = 0.019, p = 0.013, p < 0.001). Other serum acylcarnitine levels did not change significantly (p > 0.05). No difference was observed in concurrent echocardiographic measurements of left ventricular systolic function (p > 0.05). The study demonstrated that valproic acid treatment results in low levels of free carnitine and changes in some acylcarnitine subgroups but has no influence on left ventricular systolic function. Copyright © 2018 Elsevier B.V. All rights reserved.

Rectification of the background potassium current: a determinant of rotor dynamics in ventricular fibrillation.

PubMed

Samie, F H; Berenfeld, O; Anumonwo, J; Mironov, S F; Udassi, S; Beaumont, J; Taffet, S; Pertsov, A M; Jalife, J

2001-12-07

Ventricular fibrillation (VF) is the leading cause of sudden cardiac death. Yet, the mechanisms of VF remain elusive. Pixel-by-pixel spectral analysis of optical signals was carried out in video imaging experiments using a potentiometric dye in the Langendorff-perfused guinea pig heart. Dominant frequencies (peak with maximal power) were distributed throughout the ventricles in clearly demarcated domains. The fastest domain (25 to 32 Hz) was always on the anterior left ventricular (LV) wall and was shown to result from persistent rotor activity. Intermittent block and breakage of wavefronts at specific locations in the periphery of such rotors were responsible for the domain organization. Patch-clamping of ventricular myocytes from the LV and the right ventricle (RV) demonstrated an LV-to-RV drop in the amplitude of the outward component of the background rectifier current (I(B)). Computer simulations suggested that rotor stability in LV resulted from relatively small rectification of I(B) (presumably I(K1)), whereas instability, termination, and wavebreaks in RV were a consequence of strong rectification. This study provides new evidence in the isolated guinea pig heart that a persistent high-frequency rotor in the LV maintains VF, and that spatially distributed gradients in I(K1) density represent a robust ionic mechanism for rotor stabilization and wavefront fragmentation.

Burst Stimulation Improves Hemodynamics During Resuscitation after Prolonged Ventricular Fibrillation

PubMed Central

Walcott, Gregory; Melnick, Sharon; Killingsworth, Cheryl; Ideker, Raymond

2009-01-01

Background Although return of spontaneous circulation (ROSC) is frequently achieved during resuscitation for sudden cardiac arrest, systolic blood pressure can then decrease, requiring additional myocardial support. Previous studies have shown that a series of 1-ms electrical pulses delivered through the defibrillation patches during ventricular fibrillation (VF) can stimulate the autonomic nervous system to increase myocardial function following defibrillation. We hypothesized that a similar series of electrical pulses could increase myocardial function and blood pressure during the early post-resuscitation period. Methods and Results Six swine were studied that underwent 6–7 min. Each animal received 5, 10, 15, or 20 pulse packets consisting of 6 10 A, 1-ms pulses every 3–4 s in random order whenever systolic blood pressure became less than 50 mmHg. All four sets of pulse packets were delivered to each animal. Systolic blood pressure and cardiac function (left ventricular +dP/dt) were increased to pre-stimulation levels or above by all four sets of pulse packets. The increases were significantly greater for the longer than the shorter number of pulse packets. The mean±SD duration of the time that the systolic pressure remained above 50 mmHg following pulse delivery was 4.2±2.5 min. Conclusions Electrical stimulation during regular rhythm following prolonged VF and resuscitation can increase blood pressure and cardiac function to above pre-arrest levels. PMID:19655042

Spatio-temporal Organization During Ventricular Fibrillation in the Human Heart.

PubMed

Robson, Jinny; Aram, Parham; Nash, Martyn P; Bradley, Chris P; Hayward, Martin; Paterson, David J; Taggart, Peter; Clayton, Richard H; Kadirkamanathan, Visakan

2018-06-01

In this paper, we present a novel approach to quantify the spatio-temporal organization of electrical activation during human ventricular fibrillation (VF). We propose three different methods based on correlation analysis, graph theoretical measures and hierarchical clustering. Using the proposed approach, we quantified the level of spatio-temporal organization during three episodes of VF in ten patients, recorded using multi-electrode epicardial recordings with 30 s coronary perfusion, 150 s global myocardial ischaemia and 30 s reflow. Our findings show a steady decline in spatio-temporal organization from the onset of VF with coronary perfusion. We observed transient increases in spatio-temporal organization during global myocardial ischaemia. However, the decline in spatio-temporal organization continued during reflow. Our results were consistent across all patients, and were consistent with the numbers of phase singularities. Our findings show that the complex spatio-temporal patterns can be studied using complex network analysis.

Activation patterns of Purkinje fibers during long-duration ventricular fibrillation in an isolated canine heart model.

PubMed

Tabereaux, Paul B; Walcott, Greg P; Rogers, Jack M; Kim, Jong; Dosdall, Derek J; Robertson, Peter G; Killingsworth, Cheryl R; Smith, William M; Ideker, Raymond E

2007-09-04

The roles of Purkinje fibers (PFs) and focal wave fronts, if any, in the maintenance of ventricular fibrillation (VF) are unknown. If PFs are involved in VF maintenance, it should be possible to map wave fronts propagating from PFs into the working ventricular myocardium during VF. If wave fronts ever arise focally during VF, it should be possible to map them appearing de novo. Six canine hearts were isolated, and the left main coronary artery was cannulated and perfused. The left ventricular cavity was exposed, which allowed direct endocardial mapping of the anterior papillary muscle insertion. Nonperfused VF was induced, and 6 segments of data, each 5 seconds long, were analyzed during 10 minutes of VF. During 36 segments of data that were analyzed, 1018 PF or focal wave fronts of activation were identified. In 534 wave fronts, activation was mapped propagating from working ventricular myocardium to PF. In 142 wave fronts, activation was mapped propagating from PF to working ventricular myocardium. In 342 wave fronts, activation was mapped arising focally. More than 1 of these 3 patterns could occur in the same wave front. PFs are highly active throughout the first 10 minutes of VF. In addition to retrograde propagation from the working ventricular myocardium to PFs, antegrade propagation occurs from PFs to working ventricular myocardium, which suggests PFs are important in VF maintenance. Prior plunge needle recordings in dogs indicate activation propagates from the endocardium toward the epicardium after 1 minute of VF, which suggests that focal sites on the endocardium may represent foci and not breakthrough. If so, in addition to reentry, abnormal automaticity or triggered activity may also occur during VF.

The Selective Late Sodium Current Inhibitor Eleclazine, Unlike Amiodarone, Does Not Alter Defibrillation Threshold or Dominant Frequency of Ventricular Fibrillation.

PubMed

Silva, Ana F G; Bonatti, Rodolfo; Batatinha, Julio A P; Nearing, Bruce D; Zeng, Dewan; Belardinelli, Luiz; Verrier, Richard L

2017-03-01

We examined the effects of the selective late INa inhibitor eleclazine on the 50% probability of successful defibrillation (DFT50) before and after administration of amiodarone to determine its suitability for use in patients with implantable cardioverter defibrillators (ICDs). In 20 anesthetized pigs, transvenous active-fixation cardiac defibrillation leads were fluoroscopically positioned into right ventricular apex through jugular vein. ICDs were implanted subcutaneously. Dominant frequency of ventricular fibrillation was analyzed by fast Fourier transform. The measurements were made before drug administration (control), and at 40 minutes after vehicle, eleclazine (2 mg/kg, i.v., bolus over 15 minutes), or subsequent/single amiodarone administration (10 mg/kg, i.v., bolus over 10 minutes). Eleclazine did not alter DFT50, dominant frequency, heart rate, or mean arterial pressure (MAP). Subsequent amiodarone increased DFT50 (P = 0.006), decreased dominant frequency (P = 0.022), and reduced heart rate (P = 0.031) with no change in MAP. Amiodarone alone increased DFT50 (P = 0.005; NS compared to following eleclazine) and decreased dominant frequency (P = 0.003; NS compared to following eleclazine). Selective late INa inhibition with eleclazine does not alter DFT50 or dominant frequency of ventricular fibrillation when administered alone or in combination with amiodarone. Accordingly, eleclazine would not be anticipated to affect the margin of defibrillation safety in patients with ICDs.

Estimating the probability that the Taser directly causes human ventricular fibrillation.

PubMed

Sun, H; Haemmerich, D; Rahko, P S; Webster, J G

2010-04-01

This paper describes the first methodology and results for estimating the order of probability for Tasers directly causing human ventricular fibrillation (VF). The probability of an X26 Taser causing human VF was estimated using: (1) current density near the human heart estimated by using 3D finite-element (FE) models; (2) prior data of the maximum dart-to-heart distances that caused VF in pigs; (3) minimum skin-to-heart distances measured in erect humans by echocardiography; and (4) dart landing distribution estimated from police reports. The estimated mean probability of human VF was 0.001 for data from a pig having a chest wall resected to the ribs and 0.000006 for data from a pig with no resection when inserting a blunt probe. The VF probability for a given dart location decreased with the dart-to-heart horizontal distance (radius) on the skin surface.

Usefulness of microvolt T-wave alternans for prediction of ventricular tachyarrhythmic events in patients with dilated cardiomyopathy: results from a prospective observational study

NASA Technical Reports Server (NTRS)

Hohnloser, Stefan H.; Klingenheben, Thomas; Bloomfield, Daniel; Dabbous, Omar; Cohen, Richard J.

2003-01-01

OBJECTIVES: This study was designed to evaluate the ability of microvolt-level T-wave alternans (MTWA) to identify prospectively patients with idiopathic dilated cardiomyopathy (DCM) at risk of ventricular tachyarrhythmic events and to compare its predictive accuracy with that of conventional risk stratifiers. BACKGROUND: Patients with DCM are at increased risk of sudden death from ventricular tachyarrhythmias. At present, there are no established methods of assessing this risk. METHODS: A total of 137 patients with DCM underwent risk stratification through assessment of MTWA, left ventricular ejection fraction, baroreflex sensitivity (BRS), heart rate variability, presence of nonsustained ventricular tachycardia (VT), signal-averaged electrocardiogram, and presence of intraventricular conduction defect. The study end point was either sudden death, resuscitated ventricular fibrillation, or documented hemodynamically unstable VT. RESULTS: During an average follow-up of 14 +/- 6 months, MTWA and BRS were significant univariate predictors of ventricular tachyarrhythmic events (p < 0.035 and p < 0.015, respectively). Multivariate Cox regression analysis revealed that only MTWA was a significant predictor. CONCLUSIONS: Microvolt-level T-wave alternans is a powerful independent predictor of ventricular tachyarrhythmic events in patients with DCM.

A novel time-domain signal processing algorithm for real time ventricular fibrillation detection

NASA Astrophysics Data System (ADS)

Monte, G. E.; Scarone, N. C.; Liscovsky, P. O.; Rotter S/N, P.

2011-12-01

This paper presents an application of a novel algorithm for real time detection of ECG pathologies, especially ventricular fibrillation. It is based on segmentation and labeling process of an oversampled signal. After this treatment, analyzing sequence of segments, global signal behaviours are obtained in the same way like a human being does. The entire process can be seen as a morphological filtering after a smart data sampling. The algorithm does not require any ECG digital signal pre-processing, and the computational cost is low, so it can be embedded into the sensors for wearable and permanent applications. The proposed algorithms could be the input signal description to expert systems or to artificial intelligence software in order to detect other pathologies.

Effects of potassium/lidocaine-induced cardiac standstill during cardiopulmonary resuscitation in a pig model of prolonged ventricular fibrillation.

PubMed

Kook Lee, Byung; Joon Lee, Seung; Woon Jeung, Kyung; Youn Lee, Hyoung; Jeong, In Seok; Lim, Victor; Hun Jung, Yong; Heo, Tag; Il Min, Yong

2014-04-01

Several studies in patients who underwent open heart surgery found that myocardial ischemic damage was reduced by potassium cardioplegia combined with lidocaine infusion. The authors evaluated the effects of potassium/lidocaine-induced cardiac standstill during conventional cardiopulmonary resuscitation (CPR) on myocardial injury and left ventricular dysfunction after resuscitation from prolonged ventricular fibrillation (VF) cardiac arrest in a pig model. Ventricular fibrillation was induced in 16 pigs, and circulatory arrest was maintained for 14 minutes. Animals were then resuscitated by standard CPR. Animals were randomized at the start of CPR to receive 20 mL of saline (control group) or 0.9 mEq/kg potassium chloride and 1.2 mg/kg lidocaine diluted to 20 mL (K-lido group). Seven animals in each group achieved return of spontaneous circulation (ROSC; p=1.000). Four of the K-lido group animals (50%) achieved ROSC without countershock. Resuscitated animals in the K-lido group required fewer countershocks (p=0.004), smaller doses of epinephrine (p=0.009), and shorter durations of CPR (p=0.004) than did the control group. The uncorrected troponin-I at 4 hours after ROSC was lower in the K-lido group compared with the control group (2.82 ng/mL, 95% confidence interval [CI]=1.07 to 3.38 ng/mL vs. 6.55 ng/mL, 95% CI=4.84 to 13.30 ng/mL; p=0.025), although the difference was not significant after Bonferroni correction. The magnitude of reduction in left ventricular ejection fraction (LVEF) between baseline and 1 hour after ROSC was significantly lower in the K-lido group (26.5%, SD±6.1% vs. 39.1%, SD±6.8%; p=0.004). In a pig model of untreated VF cardiac arrest for 14 minutes, resuscitation with potassium/lidocaine-induced cardiac standstill during conventional CPR tended to reduce myocardial injury and decreased the severity of postresuscitation myocardial dysfunction significantly. © 2014 by the Society for Academic Emergency Medicine.

A novel mechanism for electrical currents inducing ventricular fibrillation: The three-fold way to fibrillation.

PubMed

Kroll, Mark W; Panescu, Dorin; Hinz, Andrew F; Lakkireddy, Dhanunjaya

2010-01-01

It has been long recognized that there are 2 methods for inducing VF (ventricular fibrillation) with electrical currents‥ These are: (1) delivering a high-charge shock into the cardiac T-wave, and (2) delivering lower level currents for 1-5 seconds. Present electrical safety standards are based on this understanding. We present new data showing a 3(rd) mechanism of inducing VF which involves the steps of delivering sufficient current to cause high-rate cardiac capture, causing cardiac output collapse, leading to ischemia, for sufficiently long duration, which then lowers the VFT (VF threshold) to the level of the current, which finally results in VF. This requires about 40% of the normal VF-induction current but requires a duration of minutes instead of seconds for the VF to be induced. Anesthetized and ventilated swine (n=6) had current delivered from a probe tip 10 mm from the epicardium sufficient to cause hypotensive capture but not directly induce VF within 5 s. After a median time of 90 s, VF was induced. This 3(rd) mechanism of VF induction should be studied further and considered for electrical safety standards and is relevant to long-duration TASER Electronic Control Device applications.

Hemodynamic directed cardiopulmonary resuscitation improves short-term survival from ventricular fibrillation cardiac arrest.

PubMed

Friess, Stuart H; Sutton, Robert M; Bhalala, Utpal; Maltese, Matthew R; Naim, Maryam Y; Bratinov, George; Weiland, Theodore R; Garuccio, Mia; Nadkarni, Vinay M; Becker, Lance B; Berg, Robert A

2013-12-01

During cardiopulmonary resuscitation, adequate coronary perfusion pressure is essential for establishing return of spontaneous circulation. Current American Heart Association guidelines recommend standardized interval administration of epinephrine for patients in cardiac arrest. The objective of this study was to compare short-term survival using a hemodynamic directed resuscitation strategy versus chest compression depth-directed cardiopulmonary resuscitation in a porcine model of cardiac arrest. Randomized interventional study. Preclinical animal laboratory. Twenty-four 3-month-old female swine. After 7 minutes of ventricular fibrillation, pigs were randomized to receive one of three resuscitation strategies: 1) Hemodynamic directed care (coronary perfusion pressure-20): chest compressions with depth titrated to a target systolic blood pressure of 100 mm Hg and titration of vasopressors to maintain coronary perfusion pressure greater than 20 mm Hg; 2) Depth 33 mm: target chest compression depth of 33 mm with standard American Heart Association epinephrine dosing; or 3) Depth 51 mm: target chest compression depth of 51 mm with standard American Heart Association epinephrine dosing. All animals received manual cardiopulmonary resuscitation guided by audiovisual feedback for 10 minutes before first shock. Forty-five-minute survival was higher in the coronary perfusion pressure-20 group (8 of 8) compared to depth 33 mm (1 of 8) or depth 51 mm (3 of 8) groups; p equals to 0.002. Coronary perfusion pressures were higher in the coronary perfusion pressure-20 group compared to depth 33 mm (p = 0.004) and depth 51 mm (p = 0.006) and in survivors compared to nonsurvivors (p < 0.01). Total epinephrine dosing and defibrillation attempts were not different. Hemodynamic directed resuscitation targeting coronary perfusion pressures greater than 20 mm Hg during 10 minutes of cardiopulmonary resuscitation for ventricular fibrillation cardiac arrest improves short-term survival

The Resuscitative and Pharmacokinetic Effects of Humeral Intraosseous Vasopressin in a Swine Model of Ventricular Fibrillation.

PubMed

Burgert, James M; Johnson, Arthur D; Garcia-Blanco, Jose; Fulton, Lawrence V; Loughren, Michael J

2017-06-01

Introduction The American Heart Association (AHA; Dallas, Texas USA) and European Resuscitation Council (Niel, Belgium) cardiac arrest (CA) guidelines recommend the intraosseous (IO) route when intravenous (IV) access cannot be obtained. Vasopressin has been used as an alternative to epinephrine to treat ventricular fibrillation (VF). Hypothesis/Problem Limited data exist on the pharmacokinetics and resuscitative effects of vasopressin administered by the humeral IO (HIO) route for treatment of VF. The purpose of this study was to evaluate the effects of HIO and IV vasopressin, on the occurrence, odds, and time of return of spontaneous circulation (ROSC) and pharmacokinetic measures in a swine model of VF. Twenty-seven Yorkshire-cross swine (60 to 80 kg) were assigned randomly to three groups: HIO (n=9), IV (n=9), and a control group (n=9). Ventricular fibrillation was induced and untreated for two minutes. Chest compressions began at two minutes post-arrest and vasopressin (40 U) administered at four minutes post-arrest. Serial blood specimens were collected for four minutes, then the swine were resuscitated until ROSC or 29 post-arrest minutes elapsed. Fisher's Exact test determined ROSC was significantly higher in the HIO 5/7 (71.5%) and IV 8/11 (72.7%) groups compared to the control 0/9 (0.0%; P=.001). Odds ratios of ROSC indicated no significant difference between the treatment groups (P=.68) but significant differences between the HIO and control, and the IV and control groups (P=.03 and .01, respectively). Analysis of Variance (ANOVA) indicated the mean time to ROSC for HIO and IV was 621.20 seconds (SD=204.21 seconds) and 554.50 seconds (SD=213.96 seconds), respectively, with no significant difference between the groups (U=11; P=.22). Multivariate Analysis of Variance (MANOVA) revealed the maximum plasma concentration (Cmax) and time to maximum concentration (Tmax) of vasopressin in the HIO and IV groups was 71753.9 pg/mL (SD=26744.58 pg/mL) and 61853.7 pg

Chemical ablation of the Purkinje system causes early termination and activation rate slowing of long-duration ventricular fibrillation in dogs.

PubMed

Dosdall, Derek J; Tabereaux, Paul B; Kim, Jong J; Walcott, Gregory P; Rogers, Jack M; Killingsworth, Cheryl R; Huang, Jian; Robertson, Peter G; Smith, William M; Ideker, Raymond E

2008-08-01

Endocardial mapping has suggested that Purkinje fibers may play a role in the maintenance of long-duration ventricular fibrillation (LDVF). To determine the influence of Purkinje fibers on LDVF, we chemically ablated the Purkinje system with Lugol solution and recorded endocardial and transmural activation during LDVF. Dog hearts were isolated and perfused, and the ventricular endocardium was exposed and treated with Lugol solution (n = 6) or normal Tyrode solution as a control (n = 6). The left anterior papillary muscle endocardium was mapped with a 504-electrode (21 x 24) plaque with electrodes spaced 1 mm apart. Transmural activation was recorded with a six-electrode plunge needle on each side of the plaque. Ventricular fibrillation (VF) was induced, and perfusion was halted. LDVF spontaneously terminated sooner in Lugol-ablated hearts than in control hearts (4.9 +/- 1.5 vs. 9.2 +/- 3.2 min, P = 0.01). After termination of VF, both the control and Lugol hearts were typically excitable, but only short episodes of VF could be reinduced. Endocardial activation rates were similar during the first 2 min of LDVF for Lugol-ablated and control hearts but were significantly slower in Lugol hearts by 3 min. In control hearts, the endocardium activated more rapidly than the epicardium after 4 min of LDVF with wave fronts propagating most often from the endocardium to epicardium. No difference in transmural activation rate or wave front direction was observed in Lugol hearts. Ablation of the subendocardium hastens VF spontaneous termination and alters VF activation sequences, suggesting that Purkinje fibers are important in the maintenance of LDVF.

In vivo and in vitro antiarrhythmic effects of SSR149744C in animal models of atrial fibrillation and ventricular arrhythmias.

PubMed

Gautier, Patrick; Serre, Martine; Cosnier-Pucheu, Sylvie; Djandjighian, Laurent; Roccon, Alain; Herbert, Jean-Marc; Nisato, Dino

2005-02-01

SSR149744C (2-butyl-3-{4-[3-(dibutylamino)propyl]benzoyl}-1-benzofuran-5-carboxylate isopropyl fumarate) is a new noniodinated benzofuran derivative structurally related to amiodarone and dronedarone that is currently undergoing clinical trials as an antiarrhythmic agent. As SSR149744C exhibits electrophysiological and hemodynamic properties of class I, II, III, and IV antiarrhythmic agents, the aim of this study was to evaluate its acute intravenous (IV) or oral (PO) antiarrhythmic activities in in vitro and in vivo animal models of atrial and ventricular arrhythmias. In vagally induced atrial fibrillation (AF) in anesthetized dogs, SSR149744C (3 and 10 mg/kg IV) terminated AF in all 7 dogs and prevented reinduction in 4 out of 7 dogs; effective refractory periods of right atrium were dose-dependently and frequency-independently lengthened. In low-K+ medium-induced AF models, SSR149744C (0.1 to 1 microM) prevented AF in isolated guinea pig hearts in a concentration-dependent manner. At the ventricular level, SSR149744C (0.1 to 10 mg/kg IV and 3 to 90 mg/kg PO) prevented reperfusion-induced arrhythmias in anesthetized rats with a dose-effect relationship, and, at doses of 30 to 90 mg/kg PO, it reduced early (0-24 hours) mortality following permanent left coronary artery ligature in conscious rats. The present results show that SSR149744C is an effective antiarrhythmic agent in atrial fibrillation and in ventricular arrhythmias. Like amiodarone and dronedarone, its efficiency in these animal models of arrhythmias is likely be related to its multifactorial mechanism of action.

Rotor Stability Separates Sustained Ventricular Fibrillation From Self-Terminating Episodes in Humans

PubMed Central

Krummen, David E.; Hayase, Justin; Morris, David J.; Ho, Jeffrey; Smetak, Miriam R.; Clopton, Paul; Rappel, Wouter-Jan; Narayan, Sanjiv M.

2014-01-01

Objective We mapped human ventricular fibrillation (VF) to define mechanistic differences between episodes requiring defibrillation versus those that spontaneously terminate. Background VF is a leading cause of mortality, yet episodes may also self-terminate. We hypothesized that the initial maintenance of human VF is dependent upon the formation and stability of VF rotors. Methods We enrolled 26 consecutive patients (age 64±10 years, n=13 with LV dysfunction) during ablation procedures for ventricular arrhythmias, using 64-electrode basket catheters in both ventricles to map VF prior to prompt defibrillation per IRB-approved protocol. Fifty-two inductions were attempted and 36 VF episodes were observed. Phase analysis was applied to identify bi-ventricular rotors in the first 10 seconds or until VF terminated, whichever came first (11.4±2.9 seconds to defibrillator charging). Results Rotors were present in 16 of 19 patients with VF, and in all patients with sustained VF. Sustained, but not self-limiting VF, was characterized by greater rotor stability: (1) rotors were present in 68±17% of cycles in sustained versus 11±18% of cycles in self-limiting VF (p<0.001); with (2) maximum continuous rotations greater in sustained (17±11, range 7–48) versus self-limiting VF (1.1±1.4, range 0–4, p<0.001). Additionally, biventricular rotor locations in sustained VF were conserved across multiple inductions (7/7 patients, p=0.025). Conclusions In patients with and without structural heart disease, the formation of stable rotors identifies individuals whose VF requires defibrillation from those in whom VF spontaneously self-terminates. Future work should define the mechanisms that stabilize rotors and evaluate whether rotor modulation may reduce subsequent VF risk. PMID:24794115

Studying semblances of a true killer: experimental model of human ventricular fibrillation.

PubMed

Nair, K; Farid, T; Masse, S; Umapathy, K; Watkins, S; Poku, K; Asta, J; Kusha, M; Sevaptsidis, E; Jacob, J; Floras, J S; Nanthakumar, K

2012-04-01

It is unknown whether ventricular fibrillation (VF) studied in experimental models represents in vivo human VF. First, we examined closed chest in vivo VF induced at defibrillation threshold testing (DFT) in four patients with ischemic cardiomyopathy pretransplantation. We examined VF in these same four hearts in an ex vivo human Langendorff posttransplantation. VF from DFT was compared with VF from the electrodes from a similar region in the right ventricular endocardium in the Langendorff using two parameters: the scale distribution width (extracted from continuous wavelet transform) and VF mean cycle length (CL). In a second substudy group where multielectrode phase mapping could be performed, we examined early VF intraoperatively (in vivo open chest condition) in three patients with left ventricular cardiomyopathy. We investigated early VF in the hearts of three patients in an ex vivo Langendorff and compared findings with intraoperative VF using two metrics: dominant frequency (DF) assessed by the Welch periodogram and the number of phase singularities (lasting >480 ms). Wavelet analysis (P = 0.9) and VF CL were similar between the Langendorff and the DFT groups (225 ± 13, 218 ± 24 ms; P = 0.9), indicating that wave characteristics and activation rate of VF was comparable between the two models. Intraoperative DF was slower but comparable with the Langendorff DF over the endocardium (4.6 ± 0.1, 5.0 ± 0.4 Hz; P = 0.9) and the epicardium (4.5 ± 0.2, 5.2 ± 0.4 Hz; P = 0.9). Endocardial phase singularity number (9.6 ± 5, 12.1 ± 1; P = 0.6) was lesser in number but comparable between in vivo and ex vivo VF. VF dynamics in the limited experimental human studies approximates human in vivo VF.

Ventricular Fibrillation and Tachycardia detection from surface ECG using time-frequency representation images as input dataset for machine learning.

PubMed

Mjahad, A; Rosado-Muñoz, A; Bataller-Mompeán, M; Francés-Víllora, J V; Guerrero-Martínez, J F

2017-04-01

To safely select the proper therapy for Ventricullar Fibrillation (VF) is essential to distinct it correctly from Ventricular Tachycardia (VT) and other rhythms. Provided that the required therapy would not be the same, an erroneous detection might lead to serious injuries to the patient or even cause Ventricular Fibrillation (VF). The main novelty of this paper is the use of time-frequency (t-f) representation images as the direct input to the classifier. We hypothesize that this method allow to improve classification results as it allows to eliminate the typical feature selection and extraction stage, and its corresponding loss of information. The standard AHA and MIT-BIH databases were used for evaluation and comparison with other authors. Previous to t-f Pseudo Wigner-Ville (PWV) calculation, only a basic preprocessing for denoising and signal alignment is necessary. In order to check the validity of the method independently of the classifier, four different classifiers are used: Logistic Regression with L2 Regularization (L2 RLR), Adaptive Neural Network Classifier (ANNC), Support Vector Machine (SSVM), and Bagging classifier (BAGG). The main classification results for VF detection (including flutter episodes) are 95.56% sensitivity and 98.8% specificity, 88.80% sensitivity and 99.5% specificity for ventricular tachycardia (VT), 98.98% sensitivity and 97.7% specificity for normal sinus, and 96.87% sensitivity and 99.55% specificity for other rhythms. Results shows that using t-f data representations to feed classifiers provide superior performance values than the feature selection strategies used in previous works. It opens the door to be used in any other detection applications. Copyright © 2017 Elsevier B.V. All rights reserved.

A case of brugada syndrome presenting with ventricular fibrillation storm and prominent early repolarization.

PubMed

Iizuka, Chifumi; Sato, Masahito; Kitazawa, Hitoshi; Ikeda, Yoshio; Okabe, Masaaki; Kugiyama, Kiyotaka; Aizawa, Yoshifusa

2016-01-01

A 21-year-old man developed ventricular fibrillation (VF) while drinking alcohol and was admitted to our hospital. An electrocardiogram (ECG) on admission revealed remarkably prominent slurs on the terminal part of QRS complexes in the left precordial leads and a coved type ST elevation at higher intercostal spaces. After hypothermia therapy, he underwent implantation of an implantable cardioverter-defibrillator (ICD). Standard twelve-lead follow-up ECGs revealed early repolarization pattern and an intermittent coved type ST elevation. When the coved type ST elevation appeared, the early repolarization pattern in the inferior and left precordial leads was attenuated. Prominent early repolarization pattern was the most likely trigger of the VF storm in this Brugada patient. Copyright © 2016 Elsevier Inc. All rights reserved.

β1-Adrenoceptor blocker aggravated ventricular arrhythmia.

PubMed

Wang, Yan; Patel, Dimpi; Wang, Dao Wu; Yan, Jiang Tao; Hsia, Henry H; Liu, Hao; Zhao, Chun Xia; Zuo, Hou Juan; Wang, Dao Wen

2013-11-01

To assess the impact of β1 -adrenoceptor blockers (β1 -blocker) and isoprenaline on the incidence of idiopathic repetitive ventricular arrhythmia that apparently decreases with preprocedural anxiety. From January 2010 to July 2012, six patients were identified who had idiopathic ventricular arrhythmias that apparently decreased (by greater than 90%) with preprocedural anxiety. The number of ectopic ventricular beats per hour (VPH) was calculated from Holter or telemetry monitoring to assess the ectopic burden. The mean VPH of 24 hours from Holter before admission (VPH-m) was used as baseline (100%) for normalization. β1 -Blockers, isoprenaline, and/or aminophylline were administrated successively on the ward and catheter lab to evaluate their effects on the ventricular arrhythmias. Among 97 consecutive patients with idiopathic ventricular arrhythmias, six had reduction in normalized VPHs in the hour before the scheduled procedure time from (104.6 ± 4.6%) to (2.8 ± 1.6%) possibly due to preprocedural anxiety (P < 0.05), then increased to (97.9 ± 9.7%) during β1 -blocker administration (P < 0.05), then quickly reduced to (1.6 ± 1.0%) during subsequent isoprenaline infusion. Repeated β1 -blocker quickly counteracted the inhibitory effect of isoprenaline, and VPHs increased to (120.9 ± 2.4%) from (1.6 ± 1.0%; P < 0.05). Isoprenaline and β1 -blocker showed similar effects on the arrhythmias in catheter lab. In some patients with structurally normal heart and ventricular arrhythmias there is a marked reduction of arrhythmias associated with preprocedural anxiety. These patients exhibit a reproducible sequence of β1 -blocker aggravation and catecholamine inhibition of ventricular arrhythmias, including both repetitive ventricular premature beats and monomorphic ventricular tachycardia. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

Application of machine learning techniques to analyse the effects of physical exercise in ventricular fibrillation.

PubMed

Caravaca, Juan; Soria-Olivas, Emilio; Bataller, Manuel; Serrano, Antonio J; Such-Miquel, Luis; Vila-Francés, Joan; Guerrero, Juan F

2014-02-01

This work presents the application of machine learning techniques to analyse the influence of physical exercise in the physiological properties of the heart, during ventricular fibrillation. To this end, different kinds of classifiers (linear and neural models) are used to classify between trained and sedentary rabbit hearts. The use of those classifiers in combination with a wrapper feature selection algorithm allows to extract knowledge about the most relevant features in the problem. The obtained results show that neural models outperform linear classifiers (better performance indices and a better dimensionality reduction). The most relevant features to describe the benefits of physical exercise are those related to myocardial heterogeneity, mean activation rate and activation complexity. © 2013 Published by Elsevier Ltd.

Benefits of Permanent His Bundle Pacing Combined With Atrioventricular Node Ablation in Atrial Fibrillation Patients With Heart Failure With Both Preserved and Reduced Left Ventricular Ejection Fraction.

PubMed

Huang, Weijian; Su, Lan; Wu, Shengjie; Xu, Lei; Xiao, Fangyi; Zhou, Xiaohong; Ellenbogen, Kenneth A

2017-04-01

Clinical benefits from His bundle pacing (HBP) in heart failure patients with preserved and reduced left ventricular ejection fraction are still inconclusive. This study evaluated clinical outcomes of permanent HBP in atrial fibrillation patients with narrow QRS who underwent atrioventricular node ablation for heart failure symptoms despite rate control by medication. The study enrolled 52 consecutive heart failure patients who underwent attempted atrioventricular node ablation and HBP for symptomatic atrial fibrillation. Echocardiographic left ventricular ejection fraction and left ventricular end-diastolic dimension, New York Heart Association classification and use of diuretics for heart failure were assessed during follow-up visits after permanent HBP. Of 52 patients, 42 patients (80.8%) received permanent HBP and atrioventricular node ablation with a median 20-month follow-up. There was no significant change between native and paced QRS duration (107.1±25.8 versus 105.3±23.9 milliseconds, P =0.07). Left ventricular end-diastolic dimension decreased from the baseline ( P <0.001), and left ventricular ejection fraction increased from baseline ( P <0.001) in patients with a greater improvement in heart failure with reduced ejection fraction patients (N=20) than in heart failure with preserved ejection fraction patients (N=22). New York Heart Association classification improved from a baseline 2.9±0.6 to 1.4±0.4 after HBP in heart failure with reduced ejection fraction patients and from a baseline 2.7±0.6 to 1.4±0.5 after HBP in heart failure with preserved ejection fraction patients. After 1 year of HBP, the numbers of patients who used diuretics for heart failure decreased significantly ( P <0.001) when compared to the baseline diuretics use. Permanent HBP post-atrioventricular node ablation significantly improved echocardiographic measurements and New York Heart Association classification and reduced diuretics use for heart failure management in atrial

Correlation between lumbo-ventricular perfusion and MRI-CSF flow studies in idiopathic normal pressure hydrocephalus.

PubMed

Hakim, R; Black, P M

1998-01-01

After the initial description of normal pressure hydrocephalus (NPH) and its clinical triad, there has been a continuous interest from clinicians and researchers to set different diagnostic criteria that would make the selection of candidates for shunt surgery easier and more precise. A preliminary group of 12 patients was given a diagnosis of idiopathic normal pressure hydrocephalus by clinical and radiologic criteria. Each patient underwent two different tests: a magnetic resonance imaging-cerebrospinal fluid (MRI-CSF) flow study and a lumbo-ventricular perfusion test. The purpose was to compare the correlation of the results obtained with these tests and the clinical results obtained after CSF diversion. Eleven patients were given shunts and one was managed with lumbar punctures. One year after treatment, 10 of the 12 patients had improved with good results. The MRI-CSF flow studies were reliable in six patients; there were five false negatives and one false positive. The lumbo-ventricular perfusion test showed reliability in nine patients; there were two false negatives and one false positive. In only three patients were the results of both of these tests in accordance with the outcome. Even though there are few patients in this study so far, the data suggests that at the present time the most predictive guides for the diagnosis of NPH and its outcome after shunting are the clinical criteria and the radiological findings in computed tomography (CT) and/or MRI rather than lumbo-ventricular perfusion and CSF flow studies.

Radiofrequency catheter ablation of idiopathic ventricular arrhythmias originating from intramural foci in the left ventricular outflow tract: efficacy of sequential versus simultaneous unipolar catheter ablation.

PubMed

Yamada, Takumi; Maddox, William R; McElderry, H Thomas; Doppalapudi, Harish; Plumb, Vance J; Kay, G Neal

2015-04-01

Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the efficacy of sequential and simultaneous unipolar radiofrequency catheter ablation from the endocardial and epicardial sides in treating intramural LVOT VAs. Fourteen consecutive LVOT VAs, which required sequential or simultaneous irrigated unipolar radiofrequency ablation from the endocardial and epicardial sides for their elimination, were studied. The first ablation was performed at the site with the earliest local ventricular activation and best pace map on the endocardial or epicardial side. When the first ablation was unsuccessful, the second ablation was delivered on the other surface. If this sequential unipolar ablation failed, simultaneous unipolar ablation from both sides was performed. The first ablation was performed on the epicardial side in 9 VAs and endocardial side in 5 VAs. The intramural LVOT VAs were successfully eliminated by the sequential (n=9) or simultaneous (n=5) unipolar catheter ablation. Simultaneous ablation was most likely to be required for the elimination of the VAs when the distance between the endocardial and epicardial ablation sites was >8 mm and the earliest local ventricular activation time relative to the QRS onset during the VAs of <-30 ms was recorded at those ablation sites. LVOT VAs originating from intramural foci could usually be eliminated by sequential unipolar radiofrequency ablation and sometimes required simultaneous ablation from both the endocardial and epicardial sides. © 2015 American Heart Association, Inc.

Heart failure and atrial fibrillation: current concepts and controversies.

PubMed Central

Van den Berg, M. P.; Tuinenburg, A. E.; Crijns, H. J.; Van Gelder, I. C.; Gosselink, A. T.; Lie, K. I.

1997-01-01

Heart failure and atrial fibrillation are very common, particularly in the elderly. Owing to common risk factors both disorders are often present in the same patient. In addition, there is increasing evidence of a complex, reciprocal relation between heart failure and atrial fibrillation. Thus heart failure may cause atrial fibrillation, with electromechanical feedback and neurohumoral activation playing an important mediating role. In addition, atrial fibrillation may promote heart failure; in particular, when there is an uncontrolled ventricular rate, tachycardiomyopathy may develop and thereby heart failure. Eventually, a vicious circle between heart failure and atrial fibrillation may form, in which neurohumoral activation and subtle derangement of rate control are involved. Treatment should aim at unloading of the heart, adequate control of ventricular rate, and correction of neurohumoral activation. Angiotensin converting enzyme inhibitors may help to achieve these goals. Treatment should also include an attempt to restore sinus rhythm through electrical cardioversion, though appropriate timing of cardioversion is difficult. His bundle ablation may be used to achieve adequate rate control in drug refractory cases. PMID:9155607

Sildenafil Preserves Exercise Capacity in Patients With Idiopathic Pulmonary Fibrosis and Right-sided Ventricular Dysfunction

PubMed Central

Bach, David S.; Hagan, Peter G.; Yow, Eric; Flaherty, Kevin R.; Toews, Galen B.; Anstrom, Kevin J.; Martinez, Fernando J.

2013-01-01

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with pulmonary vasculopathy. Objective: The purpose of this study was to determine whether sildenafil improves 6-min walk distance (6MWD) in subjects with IPF and right ventricular dysfunction. Methods: The IPFnet, a network of IPF research centers in the United States, conducted a randomized trial examining the effect of sildenafil on 6MWD in patients with advanced IPF, defined by carbon monoxide diffusing capacity < 35% predicted. A substudy examined 119 of 180 randomized subjects where echocardiograms were available for independent review by two cardiologists. Right ventricular (RV) hypertrophy (RVH), right ventricular systolic dysfunction (RVSD), and right ventricular systolic pressure (RVSP) were assessed. Multivariable linear regression models estimated the relationship between RV abnormality, sildenafil treatment, and changes in 6MWD, St. George’s Respiratory Questionnaire (SGRQ), the EuroQol instrument, and SF-36 Health Survey (SF-36) from enrollment to 12 weeks. Results: The prevalence of RVH and RVSD were 12.8% and 18.6%, respectively. RVSP was measurable in 71 of 119 (60%) subjects; mean RVSP was 42.5 mm Hg. In the subgroup of subjects with RVSD, subjects treated with sildenafil experienced less decrement in 6MWD (99.3 m; P = .01) and greater improvement in SGRQ (13.4 points; P = .005) and EuroQol visual analog scores (17.9 points; P = .04) than subjects receiving placebo. In the subgroup with RVH, sildenafil was not associated with change in 6MWD (P = .13), but was associated with greater relative improvement in SGRQ (14.8 points; P = .02) vs subjects receiving placebo. Sildenafil treatment in those with RVSD and RVH was not associated with change in SF-36. Conclusions: Sildenafil treatment in IPF with RVSD results in better preservation of exercise capacity as compared with placebo. Sildenafil also improves quality of life in subjects with RVH and RVSD. PMID:23732584

The prognostic impact of dynamic ventricular dyssynchrony in patients with idiopathic dilated cardiomyopathy and narrow QRS.

PubMed

D'Andrea, Antonello; Mele, Donato; Nistri, Stefano; Riegler, Lucia; Galderisi, Maurizio; Agricola, Eustachio; Losi, Maria Angela; Ballo, Piercarlo; Mondillo, Sergio; Badano, Luigi P

2013-02-01

Asynchronous myocardial contraction adversely influences left ventricular (LV) function and is therefore associated with a poor prognosis in heart failure. Exercise-induced change in ventricular dyssynchrony may be an important determinant of dynamic changes in cardiac output and mitral regurgitation. A prospective, longitudinal study was designed with pre-defined dyssynchrony index and outcome variables to test the hypothesis that dynamic dyssynchrony is associated with worse long-term event-free survival in patients with dilated cardiomyopathy (DCM) and 'narrow' QRS complex. One-hundred eighty patients (62 ± 8 years; 110 males) with NYHA class II-III, idiopathic DCM, ejection fraction ≤35%, and QRS duration <120 ms were selected. All the patients underwent standard Doppler echo, colour tissue velocity imaging (DTI), and supine bicycle exercise stress echocardiography. Cardiac synchronicity was defined, at rest and at peak exercise, as DTI velocity opposing-wall delay (significant if ≥65 ms). Outcome was defined as freedom from death, heart transplantation, or LV-assist device implantation, over a median follow-up of 48 months, and a Cox proportional hazards model was used for survival analysis. At baseline examination, DCM patients showed a reduced LV ejection fraction (31 + 4%). A significant electromechanical delay in 58 patients (32%). At the peak of physical exercise, a significant electromechanical delay was detected in 103 patients (57%). There were 41 events during the follow-up (23%): 28 cardiac deaths, 8 heart transplantations, and 5 LV-assist device implantations over 4 years. When adjusted for confounding baseline variables, LV end-diastolic volume, restrictive mitral flow pattern, severity of mitral regurgitation, and the presence of exercise-induced intraventricular dyssynchrony were the only independent determinants of an adverse outcome. In patients with idiopathic DCM and narrow QRS, the increase in echocardiographic dyssynchrony during

Ablation and pacing: improving brain perfusion and cognitive function in patients with atrial fibrillation and uncontrolled ventricular rates.

PubMed

Efimova, Irina; Efimova, Nataliya; Chernov, Vladimir; Popov, Sergey; Lishmanov, Yuri

2012-03-01

The aim of our study was to determine if ablation and pacing improved brain perfusion (BP) and cognitive function (CF) in patients with medically refractory rapidly conducted atrial fibrillation (Med Refr RCAF). The study included 17 patients with Med Refr RCAF (average age 55.3 ± 4.5 years). All patients underwent brain single photon emission computed tomography scanning with (99m) Tc-hexamethylpropylene amine oxime and comprehensive neuropsychological testing before and after 3 months following pacemaker implantation. The BP was significantly lower in all regions in patients with Med Refr RCAF compared with the control group. The greatest BP decrease was revealed in the inferior frontal (P = 0.002) and posterior parietal (P = 0.024) brain regions. These patients showed cognitive deficit in 94%. There was a direct correlation between BP and CF parameters. Ablation followed by pacemaker implantation had a positive effect on BP and CF in all patients with Med Refr RCAF. Thus, BP increased in the right inferior frontal (P = 0.01), in the left superior frontal (P = 0.007), and in the left temporal (P = 0.005) cortex. These patients demonstrated improvements in immediate and delayed verbal memory, immediate and delayed visual memory, abstract mentation, attention, psychomotor speed, as well as in learning. Patients with atrial fibrillation and rapid ventricular rates refractory to medical treatment have marked signs of brain hypoperfusion and impaired CF. Ablation and pacing improve left ventricular systolic function, thereby increasing BP and improving CF. ©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.

Effects of ventricular rate and regularity on the velocity and magnitude of left atrial appendage flow in atrial fibrillation

PubMed Central

Obel, O A; Luddington, L; Maarouf, N; Aytemir, K; Ekwall, C; Malik, M; Camm, A J

2005-01-01

Objective: To prospectively determine whether ventricular rate and regularity are significant determinants of the velocity and magnitude of left atrial appendage (LAA) flow. Design and patients: 12 patients with atrial fibrillation (AF), high degree atrioventricular block, and indwelling permanent pacemakers were studied. Setting: Cardiology department of a tertiary referral centre. Interventions: Pacing was triggered by an external programmable transcutaneous device. Patients were paced at 60, 120, and 150 beats/min in both regular and irregular rhythm. LAA flow velocity and magnitude were assessed with transoesophageal Doppler echocardiography. Main outcome measures: Peak and mean LAA inflow and outflow velocity, and time-velocity interval (TVI) of LAA flow. Results: Increasing ventricular rate was associated with significantly lower peak inflow (p < 0.01), peak outflow (p < 0.05), mean inflow (p < 0.01), and mean outflow (p < 0.05) velocities and with a lower TVI of LAA filling and emptying velocities (p < 0.01). This effect was noted at rates of 60 beats/min compared with both 120 and 150 beats/min. At a pacing rate of 120 beats/min there was a significantly higher total TVI when pacing at a regular than at an irregular rhythm (40.16 (14.6) cm v 30.74 (10.9) cm, p < 0.05). Conclusions: In this study, LAA filling velocities in patients in AF were significantly influenced by paced ventricular rate and to a much lesser extent ventricular rhythm. These results suggest that rapid ventricular rates may predispose to stasis in the LAA in AF. PMID:15894771

Reduced Sodium Current in the Lateral Ventricular Wall Induces Inferolateral J-Waves.

PubMed

Meijborg, Veronique M F; Potse, Mark; Conrath, Chantal E; Belterman, Charly N W; De Bakker, Jacques M T; Coronel, Ruben

2016-01-01

J-waves in inferolateral leads are associated with a higher risk for idiopathic ventricular fibrillation. We aimed to test potential mechanisms (depolarization or repolarization dependent) responsible for inferolateral J-waves. We hypothesized that inferolateral J-waves can be caused by regional delayed activation of myocardium that is activated late during normal conditions. Computer simulations were performed to evaluate how J-point elevation is influenced by reducing sodium current conductivity (GNa), increasing transient outward current conductivity (Gto), or cellular uncoupling in three predefined ventricular regions (lateral, anterior, or septal). Two pig hearts were Langendorff-perfused with selective perfusion with a sodium channel blocker of lateral or anterior/septal regions. Volume-conducted pseudo-electrocardiograms (ECG) were recorded to detect the presence of J-waves. Epicardial unipolar electrograms were simultaneously recorded to obtain activation times (AT). Simulation data showed that conduction slowing, caused by reduced sodium current, in lateral, but not in other regions induced inferolateral J-waves. An increase in transient outward potassium current or cellular uncoupling in the lateral zone elicited slight J-point elevations which did not meet J-wave criteria. Additional conduction slowing in the entire heart attenuated J-waves and J-point elevations on the ECG, because of masking by the QRS. Experimental data confirmed that conduction slowing attributed to sodium channel blockade in the left lateral but not in the anterior/septal ventricular region induced inferolateral J-waves. J-waves coincided with the delayed activation. Reduced sodium current in the left lateral ventricular myocardium can cause inferolateral J-waves on the ECG.

Remodelling of action potential and intracellular calcium cycling dynamics during subacute myocardial infarction promotes ventricular arrhythmias in Langendorff-perfused rabbit hearts

PubMed Central

Chou, Chung-Chuan; Zhou, Shengmei; Hayashi, Hideki; Nihei, Motoki; Liu, Yen-Bin; Wen, Ming-Shien; Yeh, San-Jou; Fishbein, Michael C; Weiss, James N; Lin, Shien-Fong; Wu, Delon; Chen, Peng-Sheng

2007-01-01

We hypothesize that remodelling of action potential and intracellular calcium (Cai) dynamics in the peri-infarct zone contributes to ventricular arrhythmogenesis in the postmyocardial infarction setting. To test this hypothesis, we performed simultaneous optical mapping of Cai and membrane potential (Vm) in the left ventricle in 15 rabbit hearts with myocardial infarction for 1 week. Ventricular premature beats frequently originated from the peri-infarct zone, and 37% showed elevation of Cai prior to Vm depolarization, suggesting reverse excitation–contraction coupling as their aetiology. During electrically induced ventricular fibrillation, the highest dominant frequency was in the peri-infarct zone in 61 of 70 episodes. The site of highest dominant frequency had steeper action potential duration restitution and was more susceptible to pacing-induced Cai alternans than sites remote from infarct. Wavebreaks during ventricular fibrillation tended to occur at sites of persistently elevated Cai. Infusion of propranolol flattened action potential duration restitution, reduced wavebreaks and converted ventricular fibrillation to ventricular tachycardia. We conclude that in the subacute phase of myocardial infarction, the peri-infarct zone exhibits regions with steep action potential duration restitution slope and unstable Cai dynamics. These changes may promote ventricular extrasystoles and increase the incidence of wavebreaks during ventricular fibrillation. Whereas increased tissue heterogeneity after subacute myocardial infarction creates a highly arrhythmogenic substrate, dynamic action potential and Cai cycling remodelling also contribute to the initiation and maintenance of ventricular fibrillation in this setting. PMID:17272354

Unique Cardiac Purkinje Fiber Transient Outward Current β-Subunit Composition

PubMed Central

Xiao, Ling; Koopmann, Tamara T.; Ördög, Balázs; Postema, Pieter G.; Verkerk, Arie O.; Iyer, Vivek; Sampson, Kevin J.; Boink, Gerard J.J.; Mamarbachi, Maya A.; Varro, Andras; Jordaens, Luc; Res, Jan; Kass, Robert S.; Wilde, Arthur A.; Bezzina, C.R.; Nattel, Stanley

2015-01-01

Rationale A chromosomal haplotype producing cardiac overexpression of dipeptidyl peptidase-like protein-6 (DPP6) causes familial idiopathic ventricular fibrillation. The molecular basis of transient outward current (Ito) in Purkinje fibers (PFs) is poorly understood. We hypothesized that DPP6 contributes to PF Ito and that its overexpression might specifically alter PF Ito properties and repolarization. Objective To assess the potential role of DPP6 in PF Ito. Methods and Results Clinical data in 5 idiopathic ventricular fibrillation patients suggested arrhythmia origin in the PF-conducting system. PF and ventricular muscle Ito had similar density, but PF Ito differed from ventricular muscle in having tetraethylammonium sensitivity and slower recovery. DPP6 overexpression significantly increased, whereas DPP6 knockdown reduced, Ito density and tetraethylammonium sensitivity in canine PF but not in ventricular muscle cells. The K+-channel interacting β-subunit K+-channel interacting protein type-2, essential for normal expression of Ito in ventricular muscle, was weakly expressed in human PFs, whereas DPP6 and frequenin (neuronal calcium sensor-1) were enriched. Heterologous expression of Kv4.3 in Chinese hamster ovary cells produced small Ito; Ito amplitude was greatly enhanced by coexpression with K+-channel interacting protein type-2 or DPP6. Coexpression of DPP6 with Kv4.3 and K+-channel interacting protein type-2 failed to alter Ito compared with Kv4.3/K+-channel interacting protein type-2 alone, but DPP6 expression with Kv4.3 and neuronal calcium sensor-1 (to mimic PF Ito composition) greatly enhanced Ito compared with Kv4.3/neuronal calcium sensor-1 and recapitulated characteristic PF kinetic/pharmacological properties. A mathematical model of cardiac PF action potentials showed that Ito enhancement can greatly accelerate PF repolarization. Conclusions These results point to a previously unknown central role of DPP6 in PF Ito, with DPP6 gain of function

Sternal Route More Effective than Tibial Route for Intraosseous Amiodarone Administration in a Swine Model of Ventricular Fibrillation.

PubMed

Burgert, James M; Martinez, Andre; O'Sullivan, Mara; Blouin, Dawn; Long, Audrey; Johnson, Arthur D

2018-01-01

The pharmacokinetics of IO administered lipid soluble amiodarone during ventricular fibrillation (VF) with ongoing CPR are unknown. This study measured mean plasma concentration over 5 minutes, maximum plasma concentration (Cmax), and time to maximum concentration (Tmax) of amiodarone administered by the sternal IO (SIO), tibial IO (TIO), and IV routes in a swine model of VF with ongoing CPR. Twenty-one Yorkshire-cross swine were randomly assigned to three groups: SIO, TIO, and IV. Ventricular fibrillation was induced under general anesthesia. After 4 minutes in VF, 300 mg amiodarone was administered as indicated by group assignment. Serial blood specimens collected at 30, 60, 90, 120, 150, 180, 240, and 300 seconds were analyzed using high performance liquid chromatography with tandem mass spectrometry. The mean plasma concentration of IV amiodarone over 5 minutes was significantly higher than the TIO group at 60 seconds (P = 0.02) and 90 seconds (P = 0.017) post-injection. No significant differences in Cmax between the groups were found (P <0.05). The Tmax of amiodarone was significantly shorter in the SIO (99 secs) and IV (86 secs) groups compared to the TIO group (215 secs); P = 0.002 and P = 0.002, respectively. The SIO and IV routes of amiodarone administration were comparable. The TIO group took nearly three times longer to reach Tmax than the SIO and IV groups, likely indicating depot of lipid-soluble amiodarone in adipose-rich tibial yellow bone marrow. The SIO route was more effective than the TIO route for amiodarone delivery in a swine model of VF with ongoing CPR. Further investigations are necessary to determine if the kinetic differences found between the SIO and TIO routes in this study affect survival of VF in humans.

Inward rectifier potassium channels control rotor frequency in ventricular fibrillation.

PubMed

Jalife, José

2009-11-01

Ventricular fibrillation (VF) is the most important cause of sudden cardiac death. While traditionally thought to result from random activation of the ventricles by multiple independent wavelets, recent evidence suggests that VF may be determined by the sustained activation of a relatively small number of reentrant sources. In addition, recent experimental data in various species as well as computer simulations have provided important clues about its ionic and molecular mechanisms, particularly in regards to the role of potassium currents in such mechanisms. The results strongly argue that the inward rectifier current, I(K1,) is an important current during functional reentry because it mediates the electrotonic interactions between the unexcited core and its immediate surroundings. In addition, I(K1) is a stabilizer of reentry due to its ability to shorten action potential duration and reduce conduction velocity near the center of rotation. Increased I(K1) prevents wave front-wave tail interactions and thus averts rotor destabilization and breakup. Other studies have shown that while the slow component of the delayed rectifier potassium current I(Ks) does not significantly modify rotor frequency or stability, it plays a major role in postrepolarization refractoriness and wave break formation. Therefore, the interplay between I(K1) and the rapid sodium inward current (I(Na)) is a major factor in the control of cardiac excitability and thus the stability and frequency of reentry, while I(Ks) is an important determinant of fibrillatory conduction.

Inward Rectifier Potassium Channels Control Rotor Frequency in Ventricular Fibrillation

PubMed Central

Jalife, José

2009-01-01

Summary Ventricular fibrillation (VF) is the most important cause of sudden cardiac death. While traditionally thought to result from random activation of the ventricles by multiple independent wavelets, recent evidence suggests that VF may be determined by the sustained activation of a relatively small number of reentrant sources. In addition, recent experimental data in various species as well as computer simulations have provided important clues about its ionic and molecular mechanisms, particularly in regards to the role of potassium currents in such mechanisms. The results strongly argue that the inward rectifier current, Ik1, is an important current during functional reentry because it mediates the electrotonic interactions between the unexcited core and its immediate surroundings. In addition, IK1 is a stabilizer of reentry due to its ability to shorten action potential duration and reducing conduction velocity near the center of rotation. Increased I K1 prevents wavefront-wavetail interactions and thus averts rotor destabilization and breakup. Other studies have shown that while the slow component of the delayed rectifier potassium current, IKs, does not significantly modify rotor frequency or stability, it plays a major role in post-repolarization refractoriness and wavebreak formation. Therefore, the interplay between IK1 and the rapid sodium inward current (INa) is a major factor in the control of cardiac excitability and therefore the stability and frequency of reentry while IKs is an important determinant of fibrillatory conduction. PMID:19880073

Atrial fibrillation associated with chocolate intake abuse and chronic salbutamol inhalation abuse.

PubMed

Patanè, Salvatore; Marte, Filippo; La Rosa, Felice Carmelo; Rocca, Roberto La

2010-11-19

The use of substances as the substrate for atrial fibrillation is not frequently recognized. Chocolate is derived from the roasted seeds of the plant theobroma cacao and its components are the methylxanthine alkaloids theobromine and caffeine. Caffeine is a methylxanthine whose primary biological effect is the competitive antagonism of the adenosine receptor. Normal consumption of caffeine was not associated with risk of atrial fibrillation or flutter. Sympathomimetic effects, due to circulating catecholamines cause the cardiac manifestations of caffeine overdose toxicity, produce tachyarrhythmias such as supraventricular tachycardia, atrial fibrillation, ventricular tachycardia, and ventricular fibrillation.The commonly used doses of inhaled or nebulized salbutamol induced no acute myocardial ischaemia, arrhythmias or changes in heart rate variability in patients with coronary artery disease and clinically stable asthma or chronic obstructive pulmonary disease. Two-week salbutamol treatment shifts the cardiovascular autonomic regulation to a new level characterized by greater sympathetic responsiveness and slight beta2-receptor tolerance. We present a case of atrial fibrillation associated with chocolate intake abuse in a 19-year-old Italian woman with chronic salbutamol inhalation abuse. This case focuses attention on chocolate intake abuse associated with chronic salbutamol abuse as the substrate for atrial fibrillation. Copyright © 2008 Elsevier Ireland Ltd. All rights reserved.

Phosphorylated tau/amyloid beta 1-42 ratio in ventricular cerebrospinal fluid reflects outcome in idiopathic normal pressure hydrocephalus

PubMed Central

2012-01-01

Background Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible cause of dementia and gait disturbance that is typically treated by operative placement of a ventriculoperitoneal shunt. The outcome from shunting is variable, and some evidence suggests that the presence of comorbid Alzheimer's disease (AD) may impact shunt outcome. Evidence also suggests that AD biomarkers in cerebrospinal fluid (CSF) may predict the presence of AD. The aim of this study was to investigate the relationship between the phosphorylated tau/amyloid beta 1-42 (ptau/Aβ1-42) ratio in ventricular CSF and shunt outcome in patients with iNPH. Methods We conducted a prospective trial with a cohort of 39 patients with suspected iNPH. Patients were clinically and psychometrically assessed prior to and approximately 4 months after ventriculoperitoneal shunting. Lumbar and ventricular CSF obtained intraoperatively, and tissue from intraoperative cortical biopsies were analyzed for AD biomarkers. Outcome measures included performance on clinical symptom scales, supplementary gait measures, and standard psychometric tests. We investigated relationships between the ptau/Aβ1-42 ratio in ventricular CSF and cortical AD pathology, initial clinical features, shunt outcome, and lumbar CSF ptau/Aβ1-42 ratios in the patients in our cohort. Results We found that high ptau/Aβ1-42 ratios in ventricular CSF correlated with the presence of cortical AD pathology. At baseline, iNPH patients with ratio values most suggestive of AD presented with better gait performance but poorer cognitive performance. Patients with high ptau/Aβ1-42 ratios also showed a less robust response to shunting on both gait and cognitive measures. Finally, in a subset of 18 patients who also underwent lumbar puncture, ventricular CSF ratios were significantly correlated with lumbar CSF ratios. Conclusions Levels of AD biomarkers in CSF correlate with the presence of cortical AD pathology and predict aspects of

Association of amplitude spectral area of the ventricular fibrillation waveform with survival of out-of-hospital ventricular fibrillation cardiac arrest.

PubMed

Indik, Julia H; Conover, Zacherie; McGovern, Meghan; Silver, Annemarie E; Spaite, Daniel W; Bobrow, Bentley J; Kern, Karl B

2014-09-30

Previous investigations of out-of-hospital cardiac arrest (OHCA) have shown that the waveform characteristic amplitude spectral area (AMSA) can predict successful defibrillation and return of spontaneous circulation (ROSC) but has not been studied previously for survival. To determine whether AMSA computed from the ventricular fibrillation (VF) waveform is associated with pre-hospital ROSC, hospital admission, and hospital discharge. Adults with witnessed OHCA and an initial rhythm of VF from an Utstein style database were studied. AMSA was measured prior to each shock and averaged for each subject (AMSA-avg). Factors such as age, sex, number of shocks, time from dispatch to monitor/defibrillator application, first shock AMSA, and AMSA-avg that could predict pre-hospital ROSC, hospital admission, and hospital discharge were analyzed by logistic regression. Eighty-nine subjects (mean age 62 ± 15 years) with a total of 286 shocks were analyzed. AMSA-avg was associated with pre-hospital ROSC (p = 0.003); a threshold of 20.9 mV-Hz had a 95% sensitivity and a 43.4% specificity. Additionally, AMSA-avg was associated with hospital admission (p < 0.001); a threshold of 21 mV-Hz had a 95% sensitivity and a 54% specificity and with hospital discharge (p < 0.001); a threshold of 25.6 mV-Hz had a 95% sensitivity and a 53% specificity. First-shock AMSA was also predictive of pre-hospital ROSC, hospital admission, and discharge. Time from dispatch to monitor/defibrillator application was associated with hospital admission (p = 0.034) but not pre-hospital ROSC or hospital discharge. AMSA is highly associated with pre-hospital ROSC, survival to hospital admission, and hospital discharge in witnessed VF OHCA. Future studies are needed to determine whether AMSA computed during resuscitation can identify patients for whom continuing current resuscitation efforts would likely be futile. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights

Detection of ventricular fibrillation in the presence of cardiopulmonary resuscitation artefacts.

PubMed

Aramendi, Elisabete; de Gauna, Sofia Ruiz; Irusta, Unai; Ruiz, Jesus; Arcocha, M Fe; Ormaetxe, Jose Miguel

2007-01-01

Providing cardiopulmonary resuscitation (CPR) to a patient in cardiac arrest introduces artefacts into the electrocardiogram (ECG), corrupting the diagnosis of the underlying heart rhythm. CPR must therefore be discontinued for reliable shock advice analysis by an automated external defibrillator (AED). Detection of ventricular fibrillation (VF) during CPR would enable CPR to continue during AED rhythm analysis, thereby increasing the likelihood of resuscitation success. This study presents a new adaptive filtering method to clean the ECG. The approach consists of a filter that adapts its characteristics to the spectral content of the signal exclusively using the surface ECG that commercial AEDs capture through standard patches. A set of 200 VF and 25 CPR artefact samples collected from real out-of-hospital interventions were used to test the method. The performance of a shock advice algorithm was evaluated before and after artefact removal. CPR artefacts were added to the ECG signals and four degrees of corruption were tested. Mean sensitivities of 97.83%, 98.27%, 98.32% and 98.02% were achieved, producing sensitivity increases of 28.44%, 49.75%, 59.10% and 64.25%, respectively, sufficient for ECG analysis during CPR. Although satisfactory and encouraging sensitivity values have been obtained, further clinical and experimental investigation is required in order to integrate this type of artefact suppressing algorithm in current AEDs.

Association between atrial fibrillation, atrial enlargement, and left ventricular geometric remodeling.

PubMed

Seko, Yuta; Kato, Takao; Haruna, Tetsuya; Izumi, Toshiaki; Miyamoto, Shoichi; Nakane, Eisaku; Inoko, Moriaki

2018-04-23

This study investigated the relationship between atrial fibrillation (AF) and left ventricular (LV) geometric patterns in a hospital-based population in Japan. We retrospectively analyzed 4444 patients who had undergone simultaneous scheduled transthoracic echocardiography (TTE) and electrocardiography during 2013. A total of 430 patients who had findings of previous myocardial infarctions (n = 419) and without the data on body surface area (n = 11) were excluded from the study. We calculated the LV mass index (LVMI) and relative wall (RWT) and categorized 4014 patients into four groups as follows: normal geometry (n = 3046); concentric remodeling (normal LVMI and high RWT, n = 437); concentric hypertrophy (high LVMI and high RWT, n = 149); and eccentric remodeling (high LVMI and normal RWT, n = 382). The mean left atrial volume indices (LAVI) were 22.5, 23.8, 33.3, and 37.0 mm/m 2 in patients with normal geometry, concentric remodeling, concentric hypertrophy, and eccentric hypertrophy, respectively. The mean LV ejection fractions (LVEF) were 62.7, 62.6, 60.8, and 53.8%, respectively, whereas the prevalence of AF was 10.4%, 10.5%, 14.8%, and 16.8% in patients with normal geometry, concentric remodeling, concentric hypertrophy, and eccentric hypertrophy, respectively. In conclusion, the prevalence of AF was increasing according to LV geometric remodeling patterns in association with LA size and LVEF.

Feedback control for stabilizing chaotic spiral waves during cardiac ventricular fibrillation

NASA Astrophysics Data System (ADS)

Uzelac, Ilija; Wikswo, John; Gray, Richard

2011-03-01

The cardiac arrhythmias that lead to ventricular fibrillation (VF) arise from electrical spiral waves (SW) rotating within the heart with a characteristic period τ . A single drifting SW can degenerate into a chaotic system of multiple SWs and VF. Hence early SW detection and termination is crucial to prevent VF. Time-delayed feedback control (TDFC) is well known approach for stabilizing unstable periodic orbits embedded in chaotic attractors. We hypothesize that cardiac SWs can be stabilized by TDFC with a time-delay of τ . Implementing this approach will require precise, closed-loop control of the charge delivered to the heart during the defibrillation process. To do this, we have developed a 2 kW arbitrary-waveform voltage-to-current converter (V2CC) with a 1 kHz bandwidth that can deliver up to 5 A at 400 V for 500 ms, and a photodiode system for recording in real time an optical electrocardiogram, OECG(t). The feedback signal driving the V2CC will be the time-difference (OECG(t) - OECG(t-T), where we hypothesize that T is τ , the period of the SW. This may dramatically decrease defibrillation voltages by using a defibrillation waveform customized to the VF event, unlike commercial capacitor defibrillators. Supported in part by NIH R01 HL58241-11 through ARRA 2009.

Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction: The CAMERA-MRI Study.

PubMed

Prabhu, Sandeep; Taylor, Andrew J; Costello, Ben T; Kaye, David M; McLellan, Alex J A; Voskoboinik, Aleksandr; Sugumar, Hariharan; Lockwood, Siobhan M; Stokes, Michael B; Pathik, Bhupesh; Nalliah, Chrishan J; Wong, Geoff R; Azzopardi, Sonia M; Gutman, Sarah J; Lee, Geoffrey; Layland, Jamie; Mariani, Justin A; Ling, Liang-Han; Kalman, Jonathan M; Kistler, Peter M

2017-10-17

Atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD) frequently co-exist despite adequate rate control. Existing randomized studies of AF and LVSD of varying etiologies have reported modest benefits with a rhythm control strategy. The goal of this study was to determine whether catheter ablation (CA) for AF could improve LVSD compared with medical rate control (MRC) where the etiology of the LVSD was unexplained, apart from the presence of AF. This multicenter, randomized clinical trial enrolled patients with persistent AF and idiopathic cardiomyopathy (left ventricular ejection fraction [LVEF] ≤45%). After optimization of rate control, patients underwent cardiac magnetic resonance (CMR) to assess LVEF and late gadolinium enhancement, indicative of ventricular fibrosis, before randomization to either CA or ongoing MRC. CA included pulmonary vein isolation and posterior wall isolation. AF burden post-CA was assessed by using an implanted loop recorder, and adequacy of MRC was assessed by using serial Holter monitoring. The primary endpoint was change in LVEF on repeat CMR at 6 months. A total of 301 patients were screened; 68 patients were enrolled between November 2013 and October 2016 and randomized with 33 in each arm (accounting for 2 dropouts). The average AF burden post-CA was 1.6 ± 5.0% at 6 months. In the intention-to-treat analysis, absolute LVEF improved by 18 ± 13% in the CA group compared with 4.4 ± 13% in the MRC group (p < 0.0001) and normalized (LVEF ≥50%) in 58% versus 9% (p = 0.0002). In those undergoing CA, the absence of late gadolinium enhancement predicted greater improvements in absolute LVEF (10.7%; p = 0.0069) and normalization at 6 months (73% vs. 29%; p = 0.0093). AF is an underappreciated reversible cause of LVSD in this population despite adequate rate control. The restoration of sinus rhythm with CA results in significant improvements in ventricular function, particularly in the absence of

A Neonate with Susceptibility to Long QT Syndrome Type 6 who Presented with Ventricular Fibrillation and Sudden Unexpected Infant Death.

PubMed

Sauer, Charles W; Marc-Aurele, Krishelle L

2016-07-28

BACKGROUND This is a case of a neonate with susceptibility to long QT syndrome (LQTS) who presented with a sudden unexpected infant death. Experts continue to debate whether universal electrocardiogram (ECG) screening of all newborns is feasible, practical, and cost-effective. CASE REPORT A 19-day-old neonate was found unresponsive by her mother. ECG showed ventricular fibrillation and a combination of a lidocaine drip plus multiple defibrillations converted the rhythm to normal sinus. Unfortunately, MRI brain imaging showed multiple infarcts and EEG showed burst suppression pattern with frequent seizures; life supportive treatment was stopped and the infant died. Genetic testing revealed two mutations in the KCNE2 gene consistent with susceptibility to LQTS type 6. CONCLUSIONS We believe this case is the first to demonstrate both a precipitating electrocardiographic and genetic cause of death for an infant with LQTS, showing a cause-and-effect relationship between LQTS mutation, ventricular arrhythmia, and death. We wonder whether universal ECG newborn screening to prevent LQTS death could have saved this baby.

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.

Left ventricular hypertrophy diagnosed after a stroke: a case report.

PubMed

Umeojiako, Wilfred Ifeanyi; Kanyal, Ritesh

2018-03-22

Stroke is a recognized clinical course of hypertrophic cardiomyopathy. This interesting case showed notable difference on the electrocardiogram of a patient 4 months prior to suffering a stroke and 10 days after suffering a stroke. The pre-stroke electrocardiogram showed atrial fibrillation with a narrow QRS complex, while the post-stroke electrocardiogram showed marked left ventricular hypertrophy. Left ventricular hypertrophy was diagnosed using the Sokolow-Lyon indices. The development of left ventricular hypertrophy a few days after suffering a stroke has not previously been reported. An 83-year-old white British woman with a background history of permanent atrial fibrillation, hypertension, and previous stroke attended the emergency department with a 2-day history of exertional dyspnea, and chest tightness. On examination, she had bibasal crepitations with a systolic murmur loudest at the apex. In-patient investigations include an electrocardiogram, blood tests, chest X-ray, contrast echocardiogram, coronary angiogram, and cardiovascular magnetic resonance imaging. An electrocardiogram showed atrial fibrillation, with inferolateral T wave inversion, and left ventricular hypertrophy. A chest X-ray showed features consistent with pulmonary edema. A contrast echocardiogram showed marked hypertrophy of the mid to apical left ventricle, appearance consistent with apical hypertrophic cardiomyopathy. Coronary angiography showed eccentric shelf-type plaque with non-flow-limiting stenosis in the left coronary artery main stem. Cardiovascular magnetic resonance imaging reported findings highly suggestive of apical hypertrophic cardiomyopathy. Our patient was treated and discharged on rivaroxaban, bisoprolol, and atorvastatin with a follow-up in the cardiomyopathy outpatient clinic. Electrocardiogram diagnosis of left ventricular hypertrophy led to the diagnosis of apical hypertrophic cardiomyopathy in this patient. Left ventricular hypertrophy was only evident a few

Assessment of Atrial Fibrillation and Ventricular Arrhythmia Risk after Bariatric Surgery by P Wave/QT Interval Dispersion.

PubMed

Yılmaz, Mustafa; Altın, Cihan; Tekin, Abdullah; Erol, Tansel; Arer, İlker; Nursal, Tarık Zafer; Törer, Nurkan; Erol, Varlık; Müderrisoğlu, Haldun

2018-04-01

The association of obesity with atrial fibrillation (AF) and with ventricular arrhythmias is well documented. The aim of this study was to investigate whether weight reduction by a laparoscopic sleeve gastrectomy has any effect on P wave dispersion (PWD), a predictor of AF, and corrected QT interval dispersion (CQTD), a marker of ventricular arrhythmias, in obese individuals. In a prospective study, a total of 114 patients (79 females, 35 males) who underwent laparoscopic sleeve gastrectomy were examined. The patients were followed 1 year. PWD and CQTD values before and 3rd, 6th, and 12th months after the surgery were calculated and compared. There was a statistically significant decline in body mass index (BMI), PWD, and CQTD values among baseline, 3rd, 6th, and 12th months (p < 0.001 for all comparisons). Correlation analysis showed a statistically significant correlation between ΔPWD and ΔBMI (r = 0.719, p < 0.001), ΔPWD and Δleft ventricular end-diastolic diameter (LVEDD) (r = 0.291, p = 0.002), ΔPWD and Δleft atrial diameter (LAD) (r = 0.65, p < 0.001), ΔCQTD and ΔBMI (r = 0.266, p = 0.004), ΔCQTD and ΔLVEDD (r = 0.35, p < 0.001), ΔCQTD and ΔLAD (r = 0.289, p = 0.002). In multiple linear regression analysis, there was a statistically significant relationship between ΔPWD and ΔBMI (β = 0.713, p < 0.001), ΔPWD and ΔLVEDD (β = 0.174, p = 0.016), ΔPWD and ΔLAD (β = 0.619, p < 0.001), ΔCQTD and ΔBMI (β = 0.247, p = 0.011), ΔCQTD and ΔLVEDD (β = 0.304, p < 0.001), ΔCQTD and ΔLAD (β = 0.235, p = 0.009). PWD and CQTD values of patients were shown to be attenuated after bariatric surgery. These results indirectly offer that there may be a reduction in risk of AF, ventricular arrhythmia, and sudden cardiac death after obesity surgery.

Reduction of Serious Adverse Events Demanding Study Exclusion in Model Development: Extracorporeal Life Support Resuscitation of Ventricular Fibrillation Cardiac Arrest in Rats.

PubMed

Warenits, Alexandra-Maria; Sterz, Fritz; Schober, Andreas; Ettl, Florian; Magnet, Ingrid Anna Maria; Högler, Sandra; Teubenbacher, Ursula; Grassmann, Daniel; Wagner, Michael; Janata, Andreas; Weihs, Wolfgang

2016-12-01

Extracorporeal life support is a promising concept for selected patients in refractory cardiogenic shock and for advanced life support of persistent ventricular fibrillation cardiac arrest. Animal models of ventricular fibrillation cardiac arrest could help to investigate new treatment strategies for successful resuscitation. Associated procedural pitfalls in establishing a rat model of extracorporeal life support resuscitation need to be replaced, refined, reduced, and reported.Anesthetized male Sprague-Dawley rats (350-600 g) (n = 126) underwent cardiac arrest induced with a pacing catheter placed into the right ventricle via a jugular cannula. Rats were resuscitated with extracorporeal life support, mechanical ventilation, defibrillation, and medication. Catheter and cannula explantation was performed if restoration of spontaneous circulation was achieved. All observed serious adverse events (SAEs) occurring in each of the experimental phases were analyzed.Restoration of spontaneous circulation could be achieved in 68 of 126 rats (54%); SAEs were observed in 76 (60%) experiments. Experimental procedures related SAEs were 62 (82%) and avoidable human errors were 14 (18%). The most common serious adverse events were caused by insertion or explantation of the venous bypass cannula and resulted in lethal bleeding, cannula dislocation, or air embolism.Establishing an extracorporeal life support model in rats has confronted us with technical challenges. Even advancements in small animal critical care management over the years delivered by an experienced team and technical modifications were not able to totally avoid such serious adverse events. Replacement, refinement, and reduction reports of serious adverse events demanding study exclusions to avoid animal resources are missing and are presented hereby.

Excito-oscillatory dynamics as a mechanism of ventricular fibrillation.

PubMed

Gray, Richard A; Huelsing, Delilah J

2008-04-01

The instabilities associated with reentrant spiral waves are of paramount importance to the initiation and maintenance of tachyarrhythmias, especially ventricular fibrillation (VF). In addition to tissue heterogeneities, there are only a few basic purported mechanisms of spiral wave breakup, most notably restitution. We test the hypothesis that oscillatory membrane properties act to destabilize spiral waves. We recorded transmembrane potential (V(m)) from isolated rabbit myocytes using a constant current stimulation protocol. We developed a mathematical model that included both the stable excitable equilibrium point at resting V(m) (-80 mV) and the unstable oscillatory equilibrium point at elevated V(m) (-10 mV). Spiral wave dynamics were studied in 2-dimensional grids using variants of the model. All models showed restitution and reproduced the experimental values of transmembrane resistance at rest and during the action potential plateau. Stable spiral waves were observed when the model showed only 1 equilibrium point. However, spatio-temporal complexity was observed if the model showed both excitable and oscillatory equilibrium points (i.e., excito-oscillatory models). The initial wave breaks resulted from oscillatory waves expanding in all directions; after a few beats, the patterns were characterized by a combination of unstable spiral waves and target patterns consistent with the patterns observed on the heart surface during VF. In our model, this VF-like activity only occurred when the single cell period of V(m) oscillations was within a specific range. The VF-like patterns observed in our excito-oscillatory models could not be explained by the existing proposed instability mechanisms. Our results introduce the important suggestion that membrane dynamics responsible for V(m) oscillations at elevated V(m) levels can destabilize spiral waves and thus may be a novel therapeutic target for preventing VF.

Quinidine revisited.

PubMed

Yang, Felix; Hanon, Sam; Lam, Patrick; Schweitzer, Paul

2009-04-01

One of the earliest antiarrhythmic drugs developed, quinidine had a significant role in the treatment of many arrhythmias. After concerns for increased risk of ventricular arrhythmia and death with quinidine emerged, the use of quinidine fell dramatically in favor of newer antiarrhythmic medications. However, recent trials have generated renewed interest in the use of quinidine. In particular, quinidine appears to be safe and efficacious in combination with verapamil for the treatment of atrial fibrillation. Quinidine has also been used successfully to treat idiopathic ventricular fibrillation, Brugada syndrome, and Short QT syndrome. Although it is one of the oldest drugs in our armamentarium, quinidine continues to have a role in modern cardiology.

Determinants of plasma NT-pro-BNP levels in patients with atrial fibrillation and preserved left ventricular ejection fraction.

PubMed

Letsas, Konstantinos P; Filippatos, Gerasimos S; Pappas, Loukas K; Mihas, Constantinos C; Markou, Virginia; Alexanian, Ioannis P; Efremidis, Michalis; Sideris, Antonios; Maisel, Alan S; Kardaras, Fotios

2009-02-01

The present study aimed to investigate the clinical and echocardiographic determinants of plasma NT-pro-BNP levels in patients with atrial fibrillation (AF) and preserved left ventricular ejection fraction (LVEF). NT-pro-BNP levels were measured in 45 patients with paroxysmal AF, 41 patients with permanent AF and 48 controls. NT-pro-BNP levels were found significantly elevated in patients with paroxysmal (215+/-815 pg/ml) and permanent AF (1,086+/-835 pg/ml) in relation to control population (86.3+/-77.9 pg/ml) (P<0.001). According to the univariate linear regression analysis, age, hypertension, beta-blocker use, left atrial diameter (LAD), LVEF and AF status (paroxysmal or permanent or both) were significantly associated with NT-pro-BNP levels (P<0.05). In multiple linear regression analysis, LVEF (B coefficient: -53.030; CI: -95.738 to -10.322; P: 0.015) and LAD (B coefficient: 285.858; CI: 23.731-547.986; P: 0.033) were significant and independent determinants of NT-pro-BNP levels. Plasma NT-pro-BNP levels were significantly higher in patients with paroxysmal and permanent AF compared to those with sinus rhythm in the setting of preserved left ventricular systolic function. LVEF and LAD were independent predictors of NT-pro-BNP levels.

Effect of varying ventricular function by extrasystolic potentiation on closure of the mitral valve.

NASA Technical Reports Server (NTRS)

Vandenberg, R. A.; Williams, J. C. P.; Sturm, R. E.; Wood , E. H.

1971-01-01

Mitral regurgitant indexes were measured by roentgen videodensitometry in anesthetized dogs without thoracotomy before, during and after extrasystolic potentiation of ventricular contraction while the atria and ventricles were driven in normal temporal sequence simultaneously or in such a way as to induce atrial fibrillation. Small amounts of mitral reflux were observed with simultaneous atrial and ventricular driving and with atrial fibrillation in the control measurements before initiation of extrasystolic potentiation. Reflux became negligible during extrasystolic potentiation and increased beyond control levels after termination of extrasystolic potentiation.

Persistent recovery of normal left ventricular function and dimension in idiopathic dilated cardiomyopathy during long‐term follow‐up: does real healing exist?

PubMed

Merlo, Marco; Stolfo, Davide; Anzini, Marco; Negri, Francesco; Pinamonti, Bruno; Barbati, Giulia; Ramani, Federica; Lenarda, Andrea Di; Sinagra, Gianfranco

2015-01-13

An important number of patients with idiopathic dilated cardiomyopathy have dramatically improved left ventricular function with optimal treatment; however, little is known about the evolution and long-term outcome of this subgroup, which shows apparent healing. This study assesses whether real healing actually exists in dilated cardiomyopathy. Persistent apparent healing was evaluated among 408 patients with dilated cardiomyopathy receiving tailored medical treatment and followed over the very long-term. Persistent apparent healing was defined as left ventricular ejection fraction ≥50% and indexed left ventricular end-diastolic diameter ≤33 mm/m(2) at both mid-term (19±4 months) and long-term (103±9 months) follow-up. At mid-term, 63 of 408 patients (15%) were apparently healed; 38 (60%; 9%of the whole population) showed persistent apparent healing at long-term evaluation. No predictors of persistent apparent healing were found. Patients with persistent apparent healing showed better heart transplant–free survival at very long-term follow-up (95% versus 71%; P=0.014) compared with nonpersistently normalized patients. Nevertheless, in the very longterm, 37% of this subgroup experienced deterioration of left ventricular systolic function, and 5% died or had heart transplantation. Persistent long-term apparent healing was evident in a remarkable proportion of dilated cardiomyopathy patients receiving optimal medical treatment and was associated with stable normalization of main clinical and laboratory features. This condition can be characterized by a decline of left ventricular function over the very long term, highlighting the relevance of serial nd individualized follow-up in all patients with dilated cardiomyopathy, especially considering the absence of predictors for longterm apparent healing.

Right ventricular outflow tract tachycardia due to a somatic cell mutation in G protein subunitalphai2.

PubMed Central

Lerman, B B; Dong, B; Stein, K M; Markowitz, S M; Linden, J; Catanzaro, D F

1998-01-01

Idiopathic ventricular tachycardia is a generic term that describes the various forms of ventricular arrhythmias that occur in patients without structural heart disease and in the absence of the long QT syndrome. Many of these tachycardias are focal in origin, localize to the right ventricular outflow tract (RVOT), terminate in response to beta blockers, verapamil, vagal maneuvers, and adenosine, and are thought to result from cAMP-mediated triggered activity. DNA was prepared from biopsy samples obtained from myocardial tissue from a patient with adenosine-insensitive idiopathic ventricular tachycardia arising from the RVOT. Genomic sequences of the inhibitory G protein Galphai2 were determined after amplification by PCR and subcloning. A point mutation (F200L) in the GTP binding domain of the inhibitory G protein Galphai2 was identified in a biopsy sample from the arrhythmogenic focus. This mutation was shown to increase intracellular cAMP concentration and inhibit suppression of cAMP by adenosine. No mutations were detected in Galphai2 sequences from myocardial tissue sampled from regions remote from the origin of tachycardia, or from peripheral lymphocytes. These findings suggest that somatic cell mutations in the cAMP-dependent signal transduction pathway occurring during myocardial development may be responsible for some forms of idiopathic ventricular tachycardia. PMID:9637720

Impact of earliest activation site location in the septal right ventricular outflow tract for identification of left vs right outflow tract origin of idiopathic ventricular arrhythmias.

PubMed

Acosta, Juan; Penela, Diego; Herczku, Csaba; Macías, Yolanda; Andreu, David; Fernández-Armenta, Juan; Cipolletta, Laura; Díaz, Andrés; Korshunov, Viatcheslav; Brugada, Josep; Mont, Lluis; Cabrera, Jose A; Sánchez-Quintana, Damián; Berruezo, Antonio

2015-04-01

The earliest activation site (EAS) location in the septal right ventricular outflow tract (RVOT) could be an additional mapping data predictor of left ventricular outflow tract (LVOT) vs RVOT origin of idiopathic ventricular arrhythmias (VAs). The purpose of this study was to assess the impact of EAS location in predicting LVOT vs RVOT origin. Macroscopic and histologic study was performed in 12 postmortem hearts. Electroanatomic maps (EAMs) from 37 patients with outflow tract (OT) VA with the EAS in the septal RVOT were analyzed. Pulmonary valve (PV) was defined by voltage scanning after validation of voltage thresholds by image integration. EAM measurements were correlated with those of macroscopic/histologic study. A cutoff value of 1.9 mV discriminated between subvalvular and supravalvular positions (90% sensitivity, 96% specificity). EAS ≥1 cm below PV excluded RVOT site of origin (SOO). According to anatomic findings (distance PV-left coronary cusp = 5 ± 3 vs PV-right coronary cusp = 11 ± 5 mm), EAS-PV distance was significantly shorter in VAs arising from left coronary cusp than from the other LVOT locations (4.2 ± 5.4 mm vs 9.2 ± 7 mm; P = .034). The 10-ms isochronal longitudinal/perpendicular diameter ratio was higher in the RVOT vs the LVOT SOO group (1.97 ± 1.2 vs 0.79 ± 0.49; P = .001). An algorithm based on EAS-PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio predicted LVOT SOO with 91% sensitivity and 100% specificity. An algorithm based on the EAS-PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio accurately predicts LVOT vs RVOT SOO in outflow tract VAs with EAS in the septal RVOT. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Flow void of cerebrospinal fluid in idiopathic normal pressure hydrocephalus of the elderly: can it predict outcome after shunting?

PubMed

Krauss, J K; Regel, J P; Vach, W; Jüngling, F D; Droste, D W; Wakhloo, A K

1997-01-01

We investigate the predictive value of cerebrospinal fluid (CSF) flow void on outcome after shunting in a prospective series of patients with idiopathic normal pressure hydrocephalus (NPH). The degree and extension of CSF flow void were examined on T2-weighted magnetic resonance imaging scans of 37 elderly patients with idiopathic NPH who underwent subsequent shunting. The degree of flow void was assessed in comparison with the signal of large cerebral arteries. The extension was evaluated via the calculation of sum scores for the occurrence of flow void in different locations of the ventricular system. Those parameters were not considered in the decision to perform shunting. CSF flow void in the aqueduct and the adjacent third and fourth ventricles of the 37 patients with idiopathic NPH was compared with that of 37 age-matched control patients. CSF flow void scores in patients with idiopathic NPH were investigated for correlations between postoperative outcome scores and ventricular width indices. No difference was found between the occurrence of aqueductal CSF flow void in patients with idiopathic NPH and the control group. A significant difference, however, was noted for the extension of the CSF flow void, which was greater in the NPH group. Postoperative improvement was found in 33 of 37 patients with idiopathic NPH at a mean follow-up of 15.6 months. Only small, statistically not significant correlations were found between CSF flow void and postoperative outcome. Flow void sum scores, however, correlated significantly with ventricular width indices. The degree and extension of CSF flow void on T2-weighted magnetic resonance imaging scans have little predictive value for outcome after shunting in patients with idiopathic NPH. The greater extension of the CSF flow void in patients with NPH is most likely related to increased ventricular width. It is not useful to consider CSF flow void findings on conventional magnetic resonance imaging scans in making the

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

Thyrotoxic Atrial Fibrillation

PubMed Central

Parmar, Malvinder S.

2005-01-01

Abstract and Introduction Abstract Atrial fibrillation is the most common cardiac complication of hyperthyroidism and occurs in 15% of patients with hyperthyroidism. It is associated with a higher risk of thromboembolism that often involves the central nervous system. Oral anticoagulation is important in the majority of these patients to prevent thromboembolic complications. These patients require adjustment in the dose of various rate-controlling agents because of increased clearance associated with hyperthyroidism and a decrease in warfarin dosage because of increased clearance of vitamin K-dependent clotting factors. The management of thyrotoxic atrial fibrillation is summarized in this clinical review. Introduction A 52-year-old woman presents with symptoms of palpitations and mild shortness of breath. She is noted to be in atrial fibrillation with a rapid ventricular response of 157 beats per minute. She gives a 1-year history of increasing fatigue, intermittent palpitations, hot flashes, and weight loss of 15 lb in the past 6 months. She denies chest pain. Examination revealed an apprehensive woman with mild proptosis and diffuse thyroid enlargement. Lungs are clear. Heart sounds are irregular and rapid. Thyroid function studies performed last week at the doctor's office show a suppressed thyroid-stimulating hormone (TSH) level of .01 with elevated free thyroxine (T4) of 60 pmol/L (normal, 9–23 pmol/L). How Should This Patient Be Managed in the Emergency Department? Management of the patient in the emergency department with thyrotoxic atrial fibrillation depends on the presence or absence of associated cardiac symptoms. A conservative management with antithyroid agents is appropriate for patients without associated cardiac complications, such as angina or heart failure. However, if the patient is symptomatic with angina or heart failure, then in addition to control of rapid heart rate, therapy to inhibit thyroid hormone release and synthesis should be

Attenuated adult biphasic shocks for prolonged pediatric ventricular fibrillation: support for pediatric automated defibrillators.

PubMed

Berg, Robert A

2004-09-01

To evaluate published data regarding the treatment of prolonged pediatric defibrillation, with special emphasis on the use of attenuated adult biphasic shocks for pediatric defibrillation. Review relevant human and animal literature. Rhythm analysis algorithms from two manufacturers of automated external defibrillators can accurately distinguish shockable from nonshockable rhythms in children. Theoretical considerations and transthoracic impedance data from animals and children suggest that pediatric defibrillation doses should not necessarily vary in a simple weight-based manner. Two piglet studies have established that an attenuated adult biphasic dosage can be successfully used for 3.5- to 24-kg animals in ventricular fibrillation. One study established that the attenuated adult biphasic dosage was at least as safe and effective as the standard monophasic weight-based dosing. This review supports the American Heart Association's new guidelines for pediatric automated external defibrillator usage: "Automated external defibrillators may be used for children 1 to 8 yrs of age who have no signs of circulation. Ideally the device should deliver a pediatric dose. The arrhythmia detection system used in the device should demonstrate high specificity for pediatric shockable rhythms, i.e., it will not recommend delivery of a shock for nonshockable rhythms."

STRUCTURAL AND FUNCTIONAL BASES OF CARDIAC FIBRILLATION. DIFFERENCES AND SIMILARITIES BETWEEN ATRIA AND VENTRICLES

PubMed Central

Filgueiras-Rama, David; Jalife, José

2016-01-01

Evidence accumulated over the last 25 years suggests that, whether in the atria or ventricles, fibrillation may be explained by the self-organization of the cardiac electrical activity into rapidly spinning rotors giving way to spiral waves that break intermittently and result in fibrillatory conduction. The dynamics and frequency of such rotors depend on the ion channel composition, excitability and refractory properties of the tissues involved, as well as on the thickness and respective three-dimensional fiber structure of the atrial and ventricular chambers. Therefore, improving the understanding of fibrillation has required the use of multidisciplinary research approaches, including optical mapping, patch clamping and molecular biology, and the application of concepts derived from the theory of wave propagation in excitable media. Moreover, translation of such concepts to the clinic has recently opened new opportunities to apply novel mechanistic approaches to therapy, particularly during atrial fibrillation ablation. Here we review the current understanding of the manner in which the underlying myocardial structure and function influence rotor initiation and maintenance during cardiac fibrillation. We also examine relevant underlying differences and similarities between atrial fibrillation and ventricular fibrillation and evaluate the latest clinical mapping technologies used to identify rotors in either arrhythmia. Altogether, the data being discussed have significantly improved our understanding of the cellular and structural bases of cardiac fibrillation and pointed toward potentially exciting new avenues for more efficient and effective identification and therapy of the most complex cardiac arrhythmias. PMID:27042693

Importance of rate control or rate regulation for improving exercise capacity and quality of life in patients with permanent atrial fibrillation and normal left ventricular function: a randomised controlled study

PubMed Central

Levy, T; Walker, S; Mason, M; Spurrell, P; Rex, S; Brant, S; Paul, V

2001-01-01

OBJECTIVE—To determine the importance of rhythm regulation or rate control in patients with permanent atrial fibrillation (AF) and normal left ventricular function.
PATIENTS AND INTERVENTIONS—Thirty six patients with a mixed fast and slow ventricular response rate to their AF were randomised to either His bundle ablation (HBA) and VVIR pacemaker (HBA group) or VVI pacemaker and atrioventricular modifying drugs (Med group). Outcomes assessed at one, three, six, and 12 months included exercise duration and quality of life.
RESULTS—Exercise duration significantly improved from baseline in both groups. There was no difference in outcome between the groups (Med +40% v HBA +20%, p = NS). The heart rate profile on exercise was similarly slowed in both groups compared to baseline. Quality of life significantly improved in both treatment arms for the modified Karolinska questionnaire (KQ) (Med +50% v HBA +50%, p = NS) and the Nottingham health profile (NHP) (Med +40% v HBA +20%, p = NS). However, for the individual symptom scores of each questionnaire more were improved in the Med group (KQ-Med 6 improved v HBA 4, NHP-Med 3 v HBA 1). Left ventricular function was equally preserved by both treatments during follow up.
CONCLUSION—In these patients control of ventricular response rate with either HBA + VVIR pacemaker or atrioventricular modifying drugs + VVI pacemaker will lead to a significant improvement in exercise duration and quality of life. Rhythm regulation by HBA did not confer additional benefit, suggesting rate control alone is necessary for the successful symptomatic treatment of these patients in permanent AF.


Keywords: ablation; atrial fibrillation; pacemaker; atrioventricular modifying drugs PMID:11156667

Role of peak current in conversion of patients with ventricular fibrillation.

PubMed

Anantharaman, Venkataraman; Wan, Paul Weng; Tay, Seow Yian; Manning, Peter George; Lim, Swee Han; Chua, Siang Jin Terrance; Mohan, Tiru; Rabind, Antony Charles; Vidya, Sudarshan; Hao, Ying

2017-07-01

Peak currents are the final arbiter of defibrillation in patients with ventricular fibrillation (VF). However, biphasic defibrillators continue to use energy in joules for electrical conversion in hopes that their impedance compensation properties will address transthoracic impedance (TTI), which must be overcome when a fixed amount of energy is delivered. However, optimal peak currents for conversion of VF remain unclear. We aimed to determine the role of peak current and optimal peak levels for conversion in collapsed VF patients. Adult, non-pregnant patients presenting with non-traumatic VF were included in the study. All defibrillations that occurred were included. Impedance values during defibrillation were used to calculate peak current values. The endpoint was return of spontaneous circulation (ROSC). Of the 197 patients analysed, 105 had ROSC. Characteristics of patients with and without ROSC were comparable. Short duration of collapse < 10 minutes correlated positively with ROSC. Generally, patients with average or high TTI converted at lower peak currents. 25% of patients with high TTI converted at 13.3 ± 2.3 A, 22.7% with average TTI at 18.2 ± 2.5 A and 18.6% with low TTI at 27.0 ± 4.7 A (p = 0.729). Highest peak current conversions were at < 15 A and 15-20 A. Of the 44 patients who achieved first-shock ROSC, 33 (75.0%) received < 20 A peak current vs. > 20 A for the remaining 11 (25%) patients (p = 0.002). For best effect, priming biphasic defibrillators to deliver specific peak currents should be considered. Copyright: © Singapore Medical Association

Role of peak current in conversion of patients with ventricular fibrillation

PubMed Central

Anantharaman, Venkataraman; Wan, Paul Weng; Tay, Seow Yian; Manning, Peter George; Lim, Swee Han; Chua, Siang Jin Terrance; Mohan, Tiru; Rabind, Antony Charles; Vidya, Sudarshan; Hao, Ying

2017-01-01

INTRODUCTION Peak currents are the final arbiter of defibrillation in patients with ventricular fibrillation (VF). However, biphasic defibrillators continue to use energy in joules for electrical conversion in hopes that their impedance compensation properties will address transthoracic impedance (TTI), which must be overcome when a fixed amount of energy is delivered. However, optimal peak currents for conversion of VF remain unclear. We aimed to determine the role of peak current and optimal peak levels for conversion in collapsed VF patients. METHODS Adult, non-pregnant patients presenting with non-traumatic VF were included in the study. All defibrillations that occurred were included. Impedance values during defibrillation were used to calculate peak current values. The endpoint was return of spontaneous circulation (ROSC). RESULTS Of the 197 patients analysed, 105 had ROSC. Characteristics of patients with and without ROSC were comparable. Short duration of collapse < 10 minutes correlated positively with ROSC. Generally, patients with average or high TTI converted at lower peak currents. 25% of patients with high TTI converted at 13.3 ± 2.3 A, 22.7% with average TTI at 18.2 ± 2.5 A and 18.6% with low TTI at 27.0 ± 4.7 A (p = 0.729). Highest peak current conversions were at < 15 A and 15–20 A. Of the 44 patients who achieved first-shock ROSC, 33 (75.0%) received < 20 A peak current vs. > 20 A for the remaining 11 (25%) patients (p = 0.002). CONCLUSION For best effect, priming biphasic defibrillators to deliver specific peak currents should be considered. PMID:28741007

Rescue pulmonary vein isolation for hemodynamically unstable atrial fibrillation storm in a patient with an acute extensive myocardial infarction.

PubMed

Morishima, Itsuro; Sone, Takahito; Tsuboi, Hideyuki; Mukawa, Hiroaki

2012-11-26

New-onset atrial fibrillation in patients hospitalized for an acute myocardial infarction often leads to hemodynamic deterioration and has serious adverse prognostic implications; mortality is particularly high in patients with congestive heart failure and/or a reduced left ventricular ejection fraction. The mechanism of atrial fibrillation in the context of an acute myocardial infarction has not been well characterized and an effective treatment other than optimal medical therapy and mechanical hemodynamic support are expected. A 71 year-old male with an acute myocardial infarction due to an occlusion of the left main coronary artery was treated with percutaneous coronary intervention. He had developed severe congestive heart failure with a left ventricular ejection fraction of 34%. The systemic circulation was maintained with an intraaortic balloon pump, continuous hemodiafiltration, and mechanical ventilation until atrial fibrillation occurred on day 3 which immediately led to cardiogenic shock. Because atrial fibrillation was refractory to intravenous amiodarone, beta-blockers, and a total of 15 electrical cardioversions, the patient underwent emergent radiofrequency catheter ablation on day 4. Soon after electrical cardioversion, ectopies from the right superior pulmonary vein triggered the initiation of atrial fibrillation. The right pulmonary veins were isolated during atrial fibrillation. Again, atrial fibrillation was electrically cardioverted, then, sinus rhythm was restored. Subsequently, the left pulmonary veins were isolated. The stabilization of the hemodynamics was successfully achieved with an increase in the blood pressure and urine volume. Hemodiafiltration and amiodarone were discontinued. The patient had been free from atrial fibrillation recurrence until he suddenly died due to ventricular fibrillation on day 9. To the best of our knowledge, this is the first report of pulmonary vein isolation for a rescue purpose applied in a patient with

Implantable Cardioverter-Defibrillator Therapy in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy: Predictors of Appropriate Therapy, Outcomes, and Complications.

PubMed

Orgeron, Gabriela M; James, Cynthia A; Te Riele, Anneline; Tichnell, Crystal; Murray, Brittney; Bhonsale, Aditya; Kamel, Ihab R; Zimmerman, Stephan L; Judge, Daniel P; Crosson, Jane; Tandri, Harikrishna; Calkins, Hugh

2017-06-06

Arrhythmogenic right ventricular dysplasia/cardiomyopathy is characterized by ventricular arrhythmias and sudden cardiac death. Once the diagnosis is established, risk stratification to determine whether implantable cardioverter-defibrillator (ICD) placement is warranted is critical. The cohort included 312 patients (163 men, age at presentation 33.6±13.9 years) with definite arrhythmogenic right ventricular dysplasia/cardiomyopathy who received an ICD. Over 8.8±7.33 years, 186 participants (60%) had appropriate ICD therapy and 58 (19%) had an intervention for ventricular fibrillation/flutter. Ventricular tachycardia at presentation (hazard ratio [HR]: 1.86; 95% confidence interval [CI], 1.38-2.49; P <0.001), inducibility on electrophysiology study (HR: 3.14; 95% CI, 1.95-5.05; P <0.001), male sex (HR: 1.62; 95% CI, 1.20-2.19; P =0.001), inverted T waves in ≥3 precordial leads (HR: 1.66; 95% CI, 1.09-2.52; P =0.018), and premature ventricular contraction count ≥1000/24 hours (HR: 2.30; 95% CI, 1.32-4.00; P =0.003) were predictors of any appropriate ICD therapy. Inducibility at electrophysiology study (HR: 2.28; 95% CI, 1.10-4.70; P =0.025) remained as the only predictor after multivariable analysis. The predictors for ventricular fibrillation/flutter were premature ventricular contraction ≥1000/24 hours (HR: 4.39; 95% CI, 1.32-14.61; P =0.016), syncope (HR: 1.85; 95% CI, 1.10-3.11; P =0.021), aged ≤30 years at presentation (HR: 1.76; 95% CI, 1.04-3.00; P <0.036), and male sex (HR: 1.73; 95% CI, 1.01-2.97; P =0.046). Younger age at presentation (HR: 3.14; 95% CI, 1.32-7.48; P =0.010) and high premature ventricular contraction burden (HR: 4.43; 95% CI, 1.35-14.57; P <0.014) remained as independent predictors of ventricular fibrillation/flutter. Complications occurred in 66 participants (21%), and 64 (21%) had inappropriate ICD interventions. Overall mortality was low at 2%, and 4% underwent heart transplantation. These findings represent an important

Brugada syndrome unmasked by accidental inhalation of gasoline vapors.

PubMed

Kranjcec, Darko; Bergovec, Mijo; Rougier, Jean-Sébastien; Raguz, Miroslav; Pavlovic, Sonja; Jespersen, Thomas; Castella, Vincent; Keller, Dagmar I; Abriel, Hugues

2007-10-01

Loss-of-function mutations in the gene SCN5A can cause Brugada syndrome (BrS), which is an inherited form of idiopathic ventricular fibrillation. We report the case of a 46-year-old patient, with no previous medical history, who had ventricular fibrillation after accidental inhalation of gasoline vapors. His electrocardiogram (ECG) showed a typical type-1 BrS pattern that persisted after the acute event. Genetic investigations allowed the identification of a novel SCN5A mutation leading to a frame-shift and early termination of the channel protein. Biochemical and cellular electrophysiology experiments confirmed the loss-of-function of the mutant allele. The patient was implanted with a cardioverter/defibrillator.

Reduced heart rate response after premature ventricular contraction depending on severity of atrial fibrillation symptoms - Analysis on heart rate turbulence in atrial fibrillation patients.

PubMed

Makimoto, Hisaki; Blockhaus, Christian; Meyer, Christian; Lin, Tina; Jungen, Christiane; Eickholt, Christian; Clasen, Lukas; Schmidt, Jan; Kurt, Muhammed; Müller, Patrick; Shin, Dong-In; Kelm, Malte; Fürnkranz, Alexander

2018-03-01

The severity of symptoms during atrial fibrillation (AF) may be influenced by heart rate and blood pressure variation, due to irregular beats and the related adaptations in baroreflex sensitivity. This study investigated whether heart rate turbulence (HRT) as a reflection of baroreflex sensitivity is related to symptom severity during AF. Ninety-seven patients (pts) who underwent electrophysiological study were enrolled. Consecutive 56 pts had paroxysmal AF (21 with milder symptoms [EHRA I or II; Group-M], 35 with severe symptoms [EHRA III or IV; Group-S]), and 41 age-matched controls without AF were included. After delivering a single ventricular extrastimulus during sinus rhythm and repeating the process 10 times, the quantification of HRT was performed by measuring turbulence onset (TO: heart rate acceleration) and turbulence slope (TS: rate of heart rate deceleration). Group-M pts showed significantly diminished TO as compared to controls and Group-S pts (P = 0.012). There was no significant difference of the TS between the 3 groups. Given that a TO ≥ 0% or TS ≤ 2.5 ms/RR was considered abnormal, Group-M pts showed significantly higher incidences of abnormal HRT as compared to controls and Group-S pts (71% vs 40% vs 21%, respectively, P = 0.0012). Regression analysis demonstrated an independent and significant association between a diminished TO and milder AF symptoms (P < 0.05). The usual heart rate acceleration after premature ventricular contraction is significantly diminished in pts with milder AF symptoms as compared to pts with severe AF symptoms. The mechanism of association between this diminished response and symptoms should be further investigated.

Performance of the 2015 International Task Force Consensus Statement Risk Stratification Algorithm for Implantable Cardioverter-Defibrillator Placement in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

PubMed

Orgeron, Gabriela M; Te Riele, Anneline; Tichnell, Crystal; Wang, Weijia; Murray, Brittney; Bhonsale, Aditya; Judge, Daniel P; Kamel, Ihab R; Zimmerman, Stephan L; Tandri, Harikrishna; Calkins, Hugh; James, Cynthia A

2018-02-01

Ventricular arrhythmias are a feared complication of arrhythmogenic right ventricular dysplasia/cardiomyopathy. In 2015, an International Task Force Consensus Statement proposed a risk stratification algorithm for implantable cardioverter-defibrillator placement in arrhythmogenic right ventricular dysplasia/cardiomyopathy. To evaluate performance of the algorithm, 365 arrhythmogenic right ventricular dysplasia/cardiomyopathy patients were classified as having a Class I, IIa, IIb, or III indication per the algorithm at baseline. Survival free from sustained ventricular arrhythmia (VT/VF) in follow-up was the primary outcome. Incidence of ventricular fibrillation/flutter cycle length <240 ms was also assessed. Two hundred twenty-four (61%) patients had a Class I implantable cardioverter-defibrillator indication; 80 (22%), Class IIa; 54 (15%), Class IIb; and 7 (2%), Class III. During a median 4.2 (interquartile range, 1.7-8.4)-year follow-up, 190 (52%) patients had VT/VF and 60 (16%) had ventricular fibrillation/flutter. Although the algorithm appropriately differentiated risk of VT/VF, incidence of VT/VF was underestimated (observed versus expected: 29.6 [95% confidence interval, 25.2-34.0] versus >10%/year Class I; 15.5 [confidence interval 11.1-21.6] versus 1% to 10%/year Class IIa). In addition, the algorithm did not differentiate survival free from ventricular fibrillation/flutter between Class I and IIa patients ( P =0.97) or for VT/VF in Class I and IIa primary prevention patients ( P =0.22). Adding Holter results (<1000 premature ventricular contractions/24 hours) to International Task Force Consensus classification differentiated risks. While the algorithm differentiates arrhythmic risk well overall, it did not distinguish ventricular fibrillation/flutter risks of patients with Class I and IIa implantable cardioverter-defibrillator indications. Limited differentiation was seen for primary prevention cases. As these are vital uncertainties in clinical decision

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

Shock Reduction With Antitachycardia Pacing Before and During Charging for Fast Ventricular Tachycardias in Patients With Implantable Defibrillators.

PubMed

Dallaglio, Paolo Domenico; Anguera, Ignasi; Martínez Ferrer, José B; Pérez, Luisa; Viñolas, Xavier; Porres, Jose Manuel; Fontenla, Adolfo; Alzueta, Javier; Martínez, Juan Gabriel; Rodríguez, Aníbal; Basterra, Nuria; Sabaté, Xavier

2017-12-11

Fast ventricular tachycardias in the ventricular fibrillation zone in patients with an implantable cardioverter-defibrillator are susceptible to antitachycardia pacing (ATP) termination. Some manufacturers allow programming 2 ATP bursts: before charging (BC) and during (DC) charging. The aim of this study was to describe the safety and effectiveness of ATP BC and DC for fast ventricular tachycardias in the ventricular fibrillation zone in patients with an implantable cardioverter-defibrillator in daily clinical practice. Data proceeded from the multicenter UMBRELLA trial, including implantable cardioverter-defibrillator patients followed up by the CareLink monitoring system. Fast ventricular tachycardias in the ventricular fibrillation zone until a cycle length of 200ms with ATP BC and/or ATP DC were included. We reviewed 542 episodes in 240 patients. Two ATP bursts (BC/DC) were programmed in 291 episodes (53.7%, 87 patients), while 251 episodes (46.3%, 153 patients) had 1 ATP burst only DC. The number of episodes terminated by 1 ATP DC was 139, representing 55.4% effectiveness (generalized estimating equation-adjusted 60.4%). There were 256 episodes terminated by 1 or 2 ATP (BC/DC), representing 88% effectiveness (generalized estimating equation-adjusted 79.3%); the OR for ATP effectiveness BC/DC vs DC was 2.5, 95%CI, 1.5-4.1; P <.001. Shocked episodes were 112 (45%) for ATP DC vs 35 (12%) for ATP BC/DC, representing an absolute reduction of 73%. The mean shocked episode duration was 16seconds for ATP DC vs 19seconds for ATP BC/DC (P=.07). The ATP DC in the ventricular fibrillation zone for fast ventricular tachycardia is moderately effective. Adding an ATP burst BC increases the overall effectiveness, reduces the need for shocks, and does not prolong episode duration. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Pharmacological modifications of the stretch-induced effects on ventricular fibrillation in perfused rabbit hearts.

PubMed

Chorro, Francisco J; Trapero, Isabel; Such-Miquel, Luis; Pelechano, Francisca; Mainar, Luis; Cánoves, Joaquín; Tormos, Alvaro; Alberola, Antonio; Hove-Madsen, Leif; Cinca, Juan; Such, Luis

2009-11-01

Stretch induces modifications in myocardial electrical and mechanical activity. Besides the effects of substances that block the stretch-activated channels, other substances could modulate the effects of stretch through different mechanisms that affect Ca(2+) handling by myocytes. Thirty-six Langendorff-perfused rabbit hearts were used to analyze the effects of the Na(+)/Ca(2+) exchanger blocker KB-R7943, propranolol, and the adenosine A(2) receptor antagonist SCH-58261 on the acceleration of ventricular fibrillation (VF) produced by acute myocardial stretching. VF recordings were obtained with two epicardial multiple electrodes before, during, and after local stretching in four experimental series: control (n = 9), KB-R7943 (1 microM, n = 9), propranolol (1 microM, n = 9), and SCH-58261 (1 microM, n = 9). Both the Na(+)/Ca(2+) exchanger blocker KB-R7943 and propranolol induced a significant reduction (P < 0.001 and P < 0.05, respectively) in the dominant frequency increments produced by stretching with respect to the control and SCH-58261 series (control = 49.9%, SCH-58261 = 52.1%, KB-R7943 = 9.5%, and propranolol = 12.5%). The median of the activation intervals, the functional refractory period, and the wavelength of the activation process during VF decreased significantly under stretch in the control and SCH-58261 series, whereas no significant variations were observed in the propranolol and KB-R7943 series, with the exception of a slight but significant decrease in the median of the fibrillation intervals in the KB-R7943 series. KB-R7943 and propranolol induced a significant reduction in the activation maps complexity increment produced by stretch with respect to the control and SCH-58261 series. In conclusion, the electrophysiological effects responsible for stretch-induced VF acceleration in the rabbit heart are reduced by the Na(+)/Ca(2+) exchanger blocker KB-R7943 and by propranolol but not by the adenosine A(2) receptor antagonist SCH-58261.

A Nonsynonymous Polymorphism in Semaphorin 3A as a Risk Factor for Human Unexplained Cardiac Arrest with Documented Ventricular Fibrillation

PubMed Central

Nakano, Yukiko; Chayama, Kazuaki; Ochi, Hidenori; Toshishige, Masaaki; Hayashida, Yasufumi; Miki, Daiki; Hayes, C. Nelson; Suzuki, Hidekazu; Tokuyama, Takehito; Oda, Noboru; Suenari, Kazuyoshi; Uchimura-Makita, Yuko; Kajihara, Kenta; Sairaku, Akinori; Motoda, Chikaaki; Fujiwara, Mai; Watanabe, Yoshikazu; Yoshida, Yukihiko; Ohkubo, Kimie; Watanabe, Ichiro; Nogami, Akihiko; Hasegawa, Kanae; Watanabe, Hiroshi; Endo, Naoto; Aiba, Takeshi; Shimizu, Wataru; Ohno, Seiko; Horie, Minoru; Arihiro, Koji; Tashiro, Satoshi; Makita, Naomasa; Kihara, Yasuki

2013-01-01

Unexplained cardiac arrest (UCA) with documented ventricular fibrillation (VF) is a major cause of sudden cardiac death. Abnormal sympathetic innervations have been shown to be a trigger of ventricular fibrillation. Further, adequate expression of SEMA3A was reported to be critical for normal patterning of cardiac sympathetic innervation. We investigated the relevance of the semaphorin 3A (SEMA3A) gene located at chromosome 5 in the etiology of UCA. Eighty-three Japanese patients diagnosed with UCA and 2,958 healthy controls from two different geographic regions in Japan were enrolled. A nonsynonymous polymorphism (I334V, rs138694505A>G) in exon 10 of the SEMA3A gene identified through resequencing was significantly associated with UCA (combined P = 0.0004, OR 3.08, 95%CI 1.67–5.7). Overall, 15.7% of UCA patients carried the risk genotype G, whereas only 5.6% did in controls. In patients with SEMA3A I334V, VF predominantly occurred at rest during the night. They showed sinus bradycardia, and their RR intervals on the 12-lead electrocardiography tended to be longer than those in patients without SEMA3A I334V (1031±111 ms versus 932±182 ms, P = 0.039). Immunofluorescence staining of cardiac biopsy specimens revealed that sympathetic nerves, which are absent in the subendocardial layer in normal hearts, extended to the subendocardial layer only in patients with SEMA3A I334V. Functional analyses revealed that the axon-repelling and axon-collapsing activities of mutant SEMA3A I334V genes were significantly weaker than those of wild-type SEMA3A genes. A high incidence of SEMA3A I334V in UCA patients and inappropriate innervation patterning in their hearts implicate involvement of the SEMA3A gene in the pathogenesis of UCA. PMID:23593010

Ventricular Fibrillation Associated With Dynamic Changes in J-Point Elevation in a Patient With Silent Thyroiditis.

PubMed

Karashima, Shigehiro; Tsuda, Toyonobu; Wakabayashi, Yusuke; Kometani, Mitsuhiro; Demura, Masashi; Ichise, Taro; Kawashiri, Masa-Aki; Takeda, Yoshiyu; Hayashi, Kenshi; Yoneda, Takashi

2018-02-01

A J wave is a common electrocardiographic finding in the general population. Individuals with prominent J waves in multiple electrocardiogram (ECG) leads have a higher risk of lethal arrhythmias than those with low-amplitude J waves. There are few reports about the relationship between thyroid function and J-wave amplitude. We report the case of a 45-year-old man who had unexpected ventricular fibrillation (VF). He had dynamic J-point elevation in multiple ECG leads. Possible early repolarization syndrome was diagnosed. He also had thyrotoxicosis caused by silent thyroiditis, and his J-wave amplitude decreased according to changes in thyroid function because of spontaneous remission of silent thyroiditis. There was a positive correlation between serum triiodothyronine levels and J-wave amplitudes. The findings in case suggested silent thyroiditis may contribute to the occurrence of VF in a patient with dynamic changes in J-point elevation in multiple ECG leads. Thyrotoxicosis is a relatively common endocrine disease; therefore, clinicians should pay attention to J-wave amplitude in the ECG of patients with thyrotoxicosis.

Effect of Erythropoietin on Postresuscitation Renal Function in a Swine Model of Ventricular Fibrillation.

PubMed

Pantazopoulos, Charalampos; Iacovidou, Nicoletta; Kouskouni, Evangelia; Pliatsika, Paraskevi; Papalois, Apostolos; Kaparos, Georgios; Barouxis, Dimitrios; Vasileiou, Panagiotis; Lelovas, Pavlos; Kotsilianou, Olympia; Pantazopoulos, Ioannis; Gkiokas, Georgios; Garosa, Clara; Faa, Gavino; Xanthos, Theodoros

2016-01-01

Purpose . To investigate the effect of EPO administration on postresuscitation renal function. Methods . Twenty-four female Landrace/Large-White piglets aged 10-15 weeks with average weight of 19 ± 2 kg were randomly assigned to 2 different groups of 12 subjects each. After the end of an 8-minute ventricular fibrillation, the control group (Group C) received saline as placebo, whereas the EPO group (Group E) received EPO 5000 U/kg. The animals were resuscitated according to the 2010 European Resuscitation Council Guidelines for Resuscitation. Results . Five animals (41.67%) from Group C and 11 animals (91.67%) from Group E achieved ROSC ( p = 0.027). Eight animals (66.67%, 5 surviving and 3 nonsurviving) from Group C suffered severe kidney damage or AKI compared to animals from Group E, in which none of the swine had evidence of severe kidney damage or AKI ( p = 0.001). There was a statistically significant difference in all tested biochemical markers between the two groups, as well as a positive correlation of creatinine with NGAL, L-FABP, and IL-18 (summed mean values' p = 0.049, 0.01, and 0.004, resp.). Conclusions . Administration of EPO protected swine from postresuscitation acute kidney injury.

Sleep-disordered breathing in patients with atrial fibrillation and normal systolic left ventricular function.

PubMed

Bitter, Thomas; Langer, Christoph; Vogt, Jürgen; Lange, Mathias; Horstkotte, Dieter; Oldenburg, Olaf

2009-03-01

Obstructive sleep apnea (OSA) is more common in patients with atrial fibrillation (AFib). Recently, an additional association between central sleep apnea/Cheyne-Stokes respiration (CSA/CSR) and AFib has been described. The aim of this study was to investigate the prevalence and type of sleep-disordered breathing in patients with AFib and normal systolic left ventricular function. 150 patients (110 men and 40 women, aged 66.1 +/- 1.7 years) underwent cardiorespiratory polygraphy, capillary blood gas analysis, measurement of NT-proBNP, and echocardiography to determine the diameter of the left atrium (LAD) and the peak systolic pulmonary artery pressure (PAP). Sleep-disordered breathing was documented in 74% of all patients with AFib (43% had OSA and 31% had CSA/CSR). Patients with CSA/CSR had a higher PAP, a higher apnea-hypopnea index, a greater LAD, and a lower capillary blood pCO(2) than patients with OSA. Patients with AFib were found to have not only a high prevalence of obstructive sleep apnea, as has been described previously, but also a high prevalence of CSA/CSR. It remains unknown whether CSA/CSR is more common in AFib because of diastolic dysfunction or whether phenomena associated with CSA/CSR predispose to AFib. Further research on this question is needed.

Effect of Erythropoietin on Postresuscitation Renal Function in a Swine Model of Ventricular Fibrillation

PubMed Central

Kouskouni, Evangelia; Pliatsika, Paraskevi; Kaparos, Georgios; Barouxis, Dimitrios; Lelovas, Pavlos; Kotsilianou, Olympia; Pantazopoulos, Ioannis; Gkiokas, Georgios; Garosa, Clara

2016-01-01

Purpose. To investigate the effect of EPO administration on postresuscitation renal function. Methods. Twenty-four female Landrace/Large-White piglets aged 10–15 weeks with average weight of 19 ± 2 kg were randomly assigned to 2 different groups of 12 subjects each. After the end of an 8-minute ventricular fibrillation, the control group (Group C) received saline as placebo, whereas the EPO group (Group E) received EPO 5000 U/kg. The animals were resuscitated according to the 2010 European Resuscitation Council Guidelines for Resuscitation. Results. Five animals (41.67%) from Group C and 11 animals (91.67%) from Group E achieved ROSC (p = 0.027). Eight animals (66.67%, 5 surviving and 3 nonsurviving) from Group C suffered severe kidney damage or AKI compared to animals from Group E, in which none of the swine had evidence of severe kidney damage or AKI (p = 0.001). There was a statistically significant difference in all tested biochemical markers between the two groups, as well as a positive correlation of creatinine with NGAL, L-FABP, and IL-18 (summed mean values' p = 0.049, 0.01, and 0.004, resp.). Conclusions. Administration of EPO protected swine from postresuscitation acute kidney injury. PMID:27847811

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.

Sudden cardiac death complicating newly diagnosed atrial fibrillation in the setting of subclinical hyperthyroidism.

PubMed

Mountantonakis, Stavros Emmanouil; Cruz Palma, Eugen

2008-01-01

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and a predictor of all-cause mortality. Subclinical hyperthyroidism is an independent risk factor for developing AF but its clinical significance in younger patients has not been established. We describe a clinical case of a 44-year-old female with newly diagnosed AF, degenerating to ventricular fibrillation in the setting of subclinical hyperthyroidism.

Significant effects of atrioventricular node ablation and pacemaker implantation on left ventricular function and long-term survival in patients with atrial fibrillation and left ventricular dysfunction.

PubMed

Ozcan, Cevher; Jahangir, Arshad; Friedman, Paul A; Munger, Thomas M; Packer, Douglas L; Hodge, David O; Hayes, David L; Gersh, Bernard J; Hammill, Stephen C; Shen, Win-Kuang

2003-07-01

Control of ventricular rate by atrioventricular node ablation and pacemaker implantation in patients with drug-refractory atrial fibrillation (AF) is associated with improved left ventricular (LV) function. The objective of this study was to determine the effect of atrioventricular node ablation on long-term survival in patients with AF and LV dysfunction. Survival was determined by the Kaplan-Meier method for 56 study patients with LV ejection fraction (EF) < or =40% who underwent atrioventricular node ablation and pacemaker implantation and 56 age- and gender-matched control patients with AF and LVEF >40%, and age- and gender-matched control subjects from Minnesota. Groups were compared using the log-rank test. In study patients (age 69 +/- 10 years; 45 men), LVEF was 26% +/- 8% and 34% +/- 13% (p <0.001) before and after ablation, respectively. During follow-up (40 +/- 23 months), 23 patients died. Observed survival was worse than that of normal subjects (p <0.001) and control patients (p = 0.005). After ablation, LVEF nearly normalized (> or =45%) in 16 study patients (29%), in whom observed survival was comparable to that of normal subjects (p = 0.37). Coronary artery disease, hyperlipidemia, chronic renal failure, previous myocardial infarction, and coronary artery operation were independent predictors for mortality. Near normalization of LVEF occurred in 29% of study patients, suggesting that AF-induced EF reduction is reversible in many patients. Normal survival in patients with reversible LV dysfunction highlights potential survival benefits of rate control. Poor survival in patients with persistent LV dysfunction confirms the importance of optimal medical therapy.

Right Ventricular Structure and Function in Idiopathic Pulmonary Fibrosis with or without Pulmonary Hypertension.

PubMed

D'Andrea, Antonello; Stanziola, Anna; Di Palma, Enza; Martino, Maria; D'Alto, Michele; Dellegrottaglie, Santo; Cocchia, Rosangela; Riegler, Lucia; Betancourt Cordido, Meredyth Vanessa; Lanza, Maurizia; Maglione, Marco; Diana, Veronica; Calabrò, Raffaele; Russo, Maria Giovanna; Vannan, Mani; Bossone, Eduardo

2016-01-01

To elucidate right ventricular (RV) function in patients with idiopathic pulmonary fibrosis (IPF) with and without pulmonary hypertension (PH) and its relation to other features of the disease. Clinical evaluation, standard Doppler echo, Doppler myocardial imaging (DMI), and 2D strain echocardiography (STE) of RV septal and lateral walls were performed in 52 IPF patients (66.5 ± 8.5 years; 27 males) and in 45 age- and sex-comparable controls using a commercial US system (MyLab Alpha, Esaote). Pulmonary artery mean pressure (mPAP) was estimated by standard echo Doppler. RV global longitudinal strain (RV GLS) was calculated by averaging RV local strains. The IPF patients were divided into 2 groups by noninvasive assessment of PH: no PH (mPAP<25 mmHg; 36 pts) and PH (mPAP ≥25 mmHg; 16 pts). Left ventricular diameters and ejection fraction were comparable between controls and IPF, while GLS was impaired in IPF (P < 0.01). RV end-diastolic diameters, wall thickness andmPAP were increased in IPF patients with PH. In addition, pulsed DMI detected in PH IPF impaired myocardial RV early diastolic (Em) peak velocity. Also peak systolic RV strain was reduced in basal and middle RV lateral free walls in IPF, as well as RV GLS (P < 0.0001). The impairment in RV wall strain was more evident when comparing controls with the no PH group than comparing the no PH group with the PH group. By multivariate analysis, independent association of RV strain with both six-minute walking test distance (P < 0.001), mPAP (P < 0.0001), as well as with forced vital capacity (FVC) % (P < 0.005) in IPF patients were observed. Impaired RV diastolic and systolic myocardial function were present even in IPF patients without PH, which indicates an early impact on RV function and structure in patients with IPF. © 2015, Wiley Periodicals, Inc.

Echocardiography-based spectrum of severe tricuspid regurgitation: the frequency of apparently idiopathic tricuspid regurgitation.

PubMed

Mutlak, Diab; Lessick, Jonathan; Reisner, Shimon A; Aronson, Doron; Dabbah, Salim; Agmon, Yoram

2007-04-01

The cause of tricuspid valve (TV) regurgitation (TR) occasionally remains unclear. The objectives of our study were to define the causal spectrum of severe TR diagnosed by echocardiography at a tertiary medical center and to assess the relative frequency and determine the clinical and echocardiographic characteristics of TR without an apparent cause (idiopathic TR). Consecutive patients with severe TR were identified by the echocardiography laboratory computerized database. The echocardiographic reports of all patients were reviewed and the causes of TR were determined. The echocardiographic studies and medical charts were reviewed in patients without an obvious cause of TR. Of 242 consecutive patients diagnosed with severe TR, organic TV disease was evident in 23 patients (9.5%) and significant pulmonary hypertension (estimated pulmonary artery systolic pressure > 50 mm Hg) in an additional 157 patients (64.9%). After further excluding patients with various confounding factors, possibly associated with occult organic TV disease or significant pulmonary hypertension, 23 patients (9.5%) had severe TR without an apparent cause. Of these, TV coaptation appeared relatively intact, allowing adequate estimation of pulmonary artery pressure, in 15 patients (6.2% of all patients with severe TR; idiopathic TR group). Patients with idiopathic TR were older (76 +/- 10 years), with a high frequency of atrial fibrillation (93%), and prominent TV annular dilatation. After excluding multiple potential causes of TR, severe TR is occasionally idiopathic. Annular dilatation (secondary to aging, atrial fibrillation, or other causes) is the likely mechanism of TR in these patients.

Vernakalant selectively prolongs atrial refractoriness with no effect on ventricular refractoriness or defibrillation threshold in pigs.

PubMed

Bechard, Jeff; Gibson, John Ken; Killingsworth, Cheryl R; Wheeler, Jeffery J; Schneidkraut, Marlowe J; Huang, Jian; Ideker, Raymond E; McAfee, Donald A

2011-03-01

Vernakalant is a novel antiarrhythmic agent that has demonstrated clinical efficacy for the treatment of atrial fibrillation. Vernakalant blocks, to various degrees, cardiac sodium and potassium channels with a pattern that suggests atrial selectivity. We hypothesized, therefore, that vernakalant would affect atrial more than ventricular effective refractory period (ERP) and have little or no effect on ventricular defibrillation threshold (DFT). Atrial and ventricular ERP and ventricular DFT were determined before and after treatment with vernakalant or vehicle in 23 anesthetized male mixed-breed pigs. Vernakalant was infused at a rate designed to achieve stable plasma levels similar to those in human clinical trials. Atrial and ventricular ERP were determined by endocardial extrastimuli delivered to the right atria or right ventricle. Defibrillation was achieved using external biphasic shocks delivered through adhesive defibrillation patches placed on the thorax after 10 seconds of electrically induced ventricular fibrillation. The DFT was estimated using the Dixon "up-and-down" method. Vernakalant significantly increased atrial ERP compared with vehicle controls (34 ± 8 versus 9 ± 7 msec, respectively) without significantly affecting ventricular ERP or DFT. This is consistent with atrial selective actions and supports the conclusion that vernakalant does not alter the efficacy of electrical defibrillation.

Cellular mechanism underlying hypothermia-induced ventricular tachycardia/ventricular fibrillation in the setting of early repolarization and the protective effect of quinidine, cilostazol, and milrinone.

PubMed

Gurabi, Zsolt; Koncz, István; Patocskai, Bence; Nesterenko, Vladislav V; Antzelevitch, Charles

2014-02-01

Hypothermia has been reported to induce ventricular tachycardia and fibrillation (VT/VF) in patients with early repolarization (ER) pattern. This study examines the cellular mechanisms underlying VT/VF associated with hypothermia in an experimental model of ER syndrome and examines the effectiveness of quinidine, cilostazol, and milrinone to prevent hypothermia-induced arrhythmias. Transmembrane action potentials were simultaneously recorded from 2 epicardial and 1 endocardial site of coronary-perfused canine left ventricular wedge preparations, together with a pseudo-ECG. A combination of NS5806 (3-10 μmol/L) and verapamil (1 μmol/L) was used to pharmacologically model the genetic mutations responsible for ER syndrome. Acetylcholine (3 μmol/L) was used to simulate increased parasympathetic tone, which is known to promote ER. In controls, lowering the temperature of the coronary perfusate to induce mild hypothermia (32°C-34°C) resulted in increased J-wave area on the ECG and accentuated epicardial action potential notch but no arrhythmic activity. In the setting of ER, hypothermia caused further accentuation of the epicardial action potential notch, leading to loss of the action potential dome at some sites but not others, thus creating the substrate for development of phase 2 reentry and VT/VF. Addition of the transient outward current antagonist quinidine (5 μmol/L) or the phosphodiesterase III inhibitors cilostazol (10 μmol/L) or milrinone (5 μmol/L) diminished the ER manifestations and prevented the hypothermia-induced phase 2 reentry and VT/VF. Hypothermia leads to VT/VF in the setting of ER by exaggerating repolarization abnormalities, leading to development of phase 2 reentry. Quinidine, cilostazol, and milrinone suppress the hypothermia-induced VT/VF by reversing the repolarization abnormalities.

Right ventricular sex differences in patients with idiopathic pulmonary arterial hypertension characterised by magnetic resonance imaging: pair-matched case controlled study.

PubMed

Swift, Andrew J; Capener, Dave; Hammerton, Charlotte; Thomas, Steven M; Elliot, Charlie; Condliffe, Robin; Wild, Jim M; Kiely, David G

2015-01-01

Sex differences exist in both the prevalence and survival of patients with idiopathic pulmonary arterial hypertension (IPAH). Men are less frequently affected by the condition but have worse outcome as compared to females. We sought to characterise the sex related differences in right ventricular remodelling in age matched male and female patients with IPAH using cardiac magnetic resonance imaging (MRI). A case controlled pair-matched study was conducted with patients matched by age and sex. Steady state free precession (SSFP) MRI of the heart was performed at 1.5T. Cardiac volume, function and mass measurements were corrected for age, sex and BSA according to reference data. 40 age and sex matched patients with IPAH were identified. The mean age was 57 (SD 17) in both male and female cohorts. Men had proportionally lower right ventricular (RV) ejection fraction, RV stroke volume and LV stroke volume than females, p=0.028, p=0.007 and p=0.013, respectively. However, there was no significant difference in RV mass or haemodynamic indices of mPAP and PVR between males and females. Male patients with IPAH have proportionally worse RV function despite similar afterload. We hypothesise that adaptive remodelling of the RV in response to increased afterload in IPAH is more effective in females.

Intracellular calcium and vulnerability to fibrillation and defibrillation in Langendorff-perfused rabbit ventricles.

PubMed

Hwang, Gyo-Seung; Hayashi, Hideki; Tang, Liang; Ogawa, Masahiro; Hernandez, Heidy; Tan, Alex Y; Li, Hongmei; Karagueuzian, Hrayr S; Weiss, James N; Lin, Shien-Fong; Chen, Peng-Sheng

2006-12-12

The role of intracellular calcium (Ca(i)) in defibrillation and vulnerability is unclear. We simultaneously mapped epicardial membrane potential and Ca(i) during shock on T-wave episodes (n=104) and attempted defibrillation episodes (n=173) in 17 Langendorff-perfused rabbit ventricles. Unsuccessful and type B successful defibrillation shocks were followed by heterogeneous distribution of Ca(i), including regions of low Ca(i) surrounded by elevated Ca(i) ("Ca(i) sinkholes") 31+/-12 ms after shock. The first postshock activation then originated from the Ca(i) sinkhole 53+/-14 ms after the shock. No sinkholes were present in type A successful defibrillation. A Ca(i) sinkhole also was present 39+/-32 ms after a shock on T that induced ventricular fibrillation, followed 22+/-15 ms later by propagated wave fronts that arose from the same site. This wave propagated to form a spiral wave and initiated ventricular fibrillation. Thapsigargin and ryanodine significantly decreased the upper limit of vulnerability and defibrillation threshold. We studied an additional 7 rabbits after left ventricular endocardial cryoablation, resulting in a thin layer of surviving epicardium. Ca(i) sinkholes occurred 31+/-12 ms after the shock, followed in 19+/-7 ms by first postshock activation in 63 episodes of unsuccessful defibrillation. At the Ca(i) sinkhole, the rise of Ca(i) preceded the rise of epicardial membrane potential in 5 episodes. There is a heterogeneous postshock distribution of Ca(i). The first postshock activation always occurs from a Ca(i) sinkhole. The Ca(i) prefluorescence at the first postshock early site suggests that reverse excitation-contraction coupling might be responsible for the initiation of postshock activations that lead to ventricular fibrillation.

Fatigue as Presenting Symptom and a High Burden of Premature Ventricular Contractions Are Independently Associated With Increased Ventricular Wall Stress in Patients With Normal Left Ventricular Function.

PubMed

van Huls van Taxis, Carine F B; Piers, Sebastiaan R D; de Riva Silva, Marta; Dekkers, Olaf M; Pijnappels, Daniël A; Schalij, Martin J; Wijnmaalen, Adrianus P; Zeppenfeld, Katja

2015-12-01

High idiopathic premature ventricular contractions (PVC) burden has been associated with PVC-induced cardiomyopathy. Patients may be symptomatic before left ventricular (LV) dysfunction develops. N-terminal pro-B-type natriuretic peptide (NT-proBNP) and circumferential end-systolic wall stress (cESS) on echocardiography are markers for increased ventricular wall stress. This study aimed to evaluate the relation between presenting symptoms, PVC burden, and increased ventricular wall stress in patients with frequent PVCs and preserved LV function. Eighty-three patients (41 men; 49±15 years) with idiopathic PVCs and normal LV function referred for PVC ablation were included. Type of symptoms (palpitations, fatigue, and [near-]syncope), PVC burden on 24-hour Holter, NT-proBNP levels, and cESS on echocardiography were assessed before and 3 months after ablation. Sustained successful ablation was defined as ≥80% PVC burden reduction during follow-up. Patients were symptomatic for 24 months (Q1-Q3, 16-60); 73% reported palpitations, 47% fatigue, and 30% (near-)syncope. Baseline PVC burden was 23±13%, median NT-proBNP 92 pg/mL (Q1-Q3 50-156), and cESS 143±35 kdyne/cm(2). Fatigue was associated with higher baseline NT-proBNP and cESS (P<0.001, P=0.011, respectively). After sustained successful ablation, achieved in 81%, NT-proBNP and cESS decreased significantly (P<0.001 and P=0.036, respectively). Fatigue was independently associated with a significantly larger reduction in NT-proBNP. In patients with nonsuccessful ablation, NT-proBNP and cESS remained unchanged. In patients with frequent PVCs and preserved LV function, fatigue was associated with higher baseline NT-proBNP and cESS, and with a significantly larger reduction in NT-proBNP after sustained successful ablation. These findings support a link between fatigue and PVC-induced increased ventricular wall stress, despite preserved LV function. © 2015 American Heart Association, Inc.

[The concise history of atrial fibrillation].

PubMed

Fazekas, Tamás

2007-01-01

The author reviews the history of atrial fibrillation, the most common sustained cardiac arrhythmia. The chaotic irregularity of arterial pulse was clearly acknowledged by most of physicians of the ancient China, Egypt and Greece. William Harvey (1578-1657), who first described the circulatory system appropriately, was probably the first to describe fibrillation of the auricles in animals in 1628. The French "clinical pathologist", Jean Baptist de Sénac (1693-1770) was the first who assumed a correlation between "rebellious palpitation" and stenosis of the mitral valve. Robert Adams (1791-1875) also reported in 1827 the association of irregular pulses and mitral stenosis. The discovery of digitalis leaf in 1785 by William Withering (1741-1799) brought relief to patients with atrial fibrillation and congestive heart failure by reducing the ventricular rate. From an analysis of simultaneously recorded arterial and venous pressure curves, the Scottish Sir James Mackenzie (1853-11925) demonstrated that a presystolic wave cannot be seen during "pulsus irregularis perpetuus", a term very first used by Heinrich Ewald Hering (1866-1948). Arthur Cushny (1866-1926) noted the similarity between pulse curves in clinical "delirium cordis" and those in dogs with atrial fibrillation. The first human ECG depicting atrial fibrillation was published by Willem Einthoven (1860-1927) in 1906. The proof of a direct connection between absolute arrhythmia and atrial fibrillation was established by two Viennese physicians, Carl Julius Rothberger and Heinrich Winterberg in 1909. Sir Thomas Lewis (1881-1945), the father of modem electrocardiography, studied electrophysiological characteristics of atrial fibrillation and has shown that its basic perpetuating mechanism is circus movement of electrical impulse (re-entry). After him, the major discoveries relating to the pathophysiology and clinical features of atrial fibrillation in the 20th century stemmed from Karel Frederick Wenckebach

Temporary ventricular overdrive pacing for electrical storm after coronary artery bypass grafting.

PubMed

Yoshida, Toshihito; Naito, Yuji; Nishimura, Kuniharu

2011-11-01

A 57-year-old man who had been receiving chemotherapy for multiple myeloma complained of chest pain and was diagnosed with coronary artery disease. Coronary artery bypass grafting without cardiopulmonary bypass was performed smoothly, and extubation was done in the operating room. The next evening, cluster of ventricular tachycardia and fibrillation triggered by ventricular premature contractions occurred and required multiple electrical defibrillations. Despite intravenous administration of lidocaine, amiodarone, magnesium, and β-blocker, the storm sustained and was suppressed only by temporary ventricular overdrive pacing. He was discharged on foot.

Atrial fibrillation management in a breeding stallion.

PubMed

Heliczer, N; Mitchell, K; Lorello, O; Dauvillier, J; Burger, D; Schwarzwald, C C; Navas de Solis, C

2017-06-01

A 20-year-old warmblood breeding stallion presented to a University practice for semen collection and evaluation was incidentally diagnosed with atrial fibrillation (AF). Electrocardiogram recordings during breeding revealed inappropriately rapid tachycardia and occasional ventricular premature depolarizations/aberrant ventricular conduction. Transvenous electrical cardioversion was performed. After successful cardioversion the horse displayed supraventricular ectopy and atrial contractile dysfunction and was administered sotalol hydrochloride in an attempt to decrease the risk of AF recurrence. Supraventricular ectopy and echocardiographic evidence of atrial dysfunction gradually improved and normalized over 6 months. No direct adverse effects of the chronic anti-arrhythmic treatment were observed and libido and semen quality were unaffected. AF recurred 6 months after cardioversion and sotalol therapy was continued to control the ventricular ectopy/aberrant ventricular conduction during semen collection. Considerations regarding pathologic arrhythmias and inappropriately high heart rates in breeding stallions with AF may be similar to those in riding horses. Sotalol hydrochloride was a safe anti-arrhythmic drug in the management of this case. Copyright © 2017 Elsevier B.V. All rights reserved.

Impaired Cerebral Mitochondrial Oxidative Phosphorylation Function in a Rat Model of Ventricular Fibrillation and Cardiopulmonary Resuscitation

PubMed Central

Fu, Yue; Xu, Wen; Jiang, Longyuan; Huang, Zitong

2014-01-01

Postcardiac arrest brain injury significantly contributes to mortality and morbidity in patients suffering from cardiac arrest (CA). Evidence that shows that mitochondrial dysfunction appears to be a key factor in tissue damage after ischemia/reperfusion is accumulating. However, limited data are available regarding the cerebral mitochondrial dysfunction during CA and cardiopulmonary resuscitation (CPR) and its relationship to the alterations of high-energy phosphate. Here, we sought to identify alterations of mitochondrial morphology and oxidative phosphorylation function as well as high-energy phosphates during CA and CPR in a rat model of ventricular fibrillation (VF). We found that impairment of mitochondrial respiration and partial depletion of adenosine triphosphate (ATP) and phosphocreatine (PCr) developed in the cerebral cortex and hippocampus following a prolonged cardiac arrest. Optimal CPR might ameliorate the deranged phosphorus metabolism and preserve mitochondrial function. No obvious ultrastructural abnormalities of mitochondria have been found during CA. We conclude that CA causes cerebral mitochondrial dysfunction along with decay of high-energy phosphates, which would be mitigated with CPR. This study may broaden our understanding of the pathogenic processes underlying global cerebral ischemic injury and provide a potential therapeutic strategy that aimed at preserving cerebral mitochondrial function during CA. PMID:24696844

Association of left ventricular late gadolinium enhancement with left atrial low voltage areas in patients with atrial fibrillation.

PubMed

Stegmann, Clara; Jahnke, Cosima; Paetsch, Ingo; Hilbert, Sebastian; Arya, Arash; Bollmann, Andreas; Hindricks, Gerhard; Sommer, Philipp

2018-02-06

Presence of late gadolinium enhancement (LGE) is related to adverse cardiovascular outcome. Many patients suffering from atrial fibrillation (AF) undergo cardiovascular magnetic resonance (CMR) imaging prior to ablation. Since quantification of atrial fibrosis still lacks reproducibility, we sought to investigate risk factors for the presence of left ventricular (LV)-LGE and a possible correlation between ventricular fibrosis as defined by positive LGE and pathological atrial voltage maps evaluated by 3D mapping systems. Between May 2015 and January 2017, 241 patients with AF (73% persistent AF, 71% male, mean age 62.8 ± 10.1 years, Redo procedure in 24%, AF history 4.5 ± 5.2 years) underwent CMR including LV LGE prior to pulmonary vein (PV) isolation at Heart Center Leipzig. Depending on CMR results, two groups were separated: 'LV-LGE negative' (Group A, n = 197, 82%) and 'LV-LGE positive' (Group B, n = 44, 18%). To identify low voltage areas (LVA), a 3D electro-anatomic map was created during PV isolation. Multivariate analysis revealed male gender [odds ratio (OR) 7.6, 95% confidence interval (95% CI) 2.4-23.9, P = 0.001] and an increased CHA2DS2VASc Score (OR 1.6, 95% CI 1.2-2.2, P = 0.004) as significantly associated with LV-LGE. Impaired left ventricular ejection fraction, LV dilatation, larger LA size and, enlarged septum diameter occurred significantly more often in the 'LGE positive' group. Low voltage areas were detected in 83 patients overall (34%): Group A: n = 64/197 (33%), Group B: n = 19/44 (43%) (P = 0.177). Male gender and high CHA2DS2VASc Score are significantly associated with presence of LV-LGE, but LV-LGE is not associated with left atrial LVA. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.

Cardiac iron deposition in idiopathic hemochromatosis: histologic and analytic assessment of 14 hearts from autopsy.

PubMed

Olson, L J; Edwards, W D; McCall, J T; Ilstrup, D M; Gersh, B J

1987-12-01

In each heart taken from autopsies of 14 men with idiopathic hemochromatosis, the conduction system, atria and 10 sites in the ventricles were histologically graded for stainable iron. Stainable iron was exclusively sarcoplasmic; none was observed in the interstitium. The histologic grade for the same anatomic site varied among hearts and among different anatomic sites in the same heart. Ten hearts had stainable iron in all ventricular sites; one of the three hearts from patients who had undergone therapeutic phlebotomy had no iron at any site. Seven hearts had iron in the atria but at a lesser grade than that found in the ventricles; six hearts had mild focal iron deposition in the atrioventricular conduction system. None of the 14 hearts had stainable iron in the sinus node. Elemental iron was quantitated by atomic absorption spectroscopy in ventricular specimens contiguous to those studied histologically and also in age-matched control hearts. Elemental iron content was markedly increased in hearts with idiopathic hemochromatosis compared with control hearts (p less than 0.01). The quantity of elemental iron varied greatly, similar to stainable iron, but was highest subepicardially. Among the hearts from the 11 patients without prior phlebotomy, three had no stainable iron in the right ventricular septal subendocardium, suggesting that sampling error may be a problem in the evaluation of hemochromatosis by endomyocardial biopsy. The sarcoplasmic location of the iron indicates that cardiac involvement in idiopathic hemochromatosis represents a storage disease and not an infiltrative process; this finding is consistent with the normal ventricular wall thicknesses observed.

Determinants of 6-minute walk distance in patients with idiopathic pulmonary fibrosis undergoing lung transplant evaluation.

PubMed

Porteous, Mary K; Rivera-Lebron, Belinda N; Kreider, Maryl; Lee, James; Kawut, Steven M

2016-03-01

Little is known about the physiologic determinants of 6-minute walk distance in idiopathic pulmonary fibrosis. We investigated the demographic, pulmonary function, echocardiographic, and hemodynamic determinants of 6-minute walk distance in patients with idiopathic pulmonary fibrosis evaluated for lung transplantation. We performed a cross-sectional analysis of 130 patients with idiopathic pulmonary fibrosis who completed a lung transplantation evaluation at the Hospital of the University of Pennsylvania between 2005 and 2010. Multivariable linear regression analysis was used to generate an explanatory model for 6-minute walk distance. After adjustment for age, sex, race, height, and weight, the presence of right ventricular dilation was associated with a decrease of 50.9 m (95% confidence interval [CI], 8.4-93.3) in 6-minute walk distance ([Formula: see text]). For each 200-mL reduction in forced vital capacity, the walk distance decreased by 15.0 m (95% CI, 9.0-21.1; [Formula: see text]). For every increase of 1 Wood unit in pulmonary vascular resistance, the walk distance decreased by 17.3 m (95% CI, 5.1-29.5; [Formula: see text]). Six-minute walk distance in idiopathic pulmonary fibrosis depends in part on circulatory impairment and the degree of restrictive lung disease. Future trials that target right ventricular morphology, pulmonary vascular resistance, and forced vital capacity may potentially improve exercise capacity in patients with idiopathic pulmonary fibrosis.

Ventricular Cycle Length Characteristics Estimative of Prolonged RR Interval during Atrial Fibrillation

PubMed Central

CIACCIO, EDWARD J.; BIVIANO, ANGELO B.; GAMBHIR, ALOK; EINSTEIN, ANDREW J.; GARAN, HASAN

2014-01-01

Background When atrial fibrillation (AF) is incessant, imaging during a prolonged ventricular RR interval may improve image quality. It was hypothesized that long RR intervals could be predicted from preceding RR values. Methods From the PhysioNet database, electrocardiogram RR intervals were obtained from 74 persistent AF patients. An RR interval lengthened by at least 250 ms beyond the immediately preceding RR interval (termed T0 and T1, respectively) was considered prolonged. A two-parameter scatterplot was used to predict the occurrence of a prolonged interval T0. The scatterplot parameters were: (1) RR variability (RRv) estimated as the average second derivative from 10 previous pairs of RR differences, T13–T2, and (2) Tm–T1, the difference between Tm, the mean from T13 to T2, and T1. For each patient, scatterplots were constructed using preliminary data from the first hour. The ranges of parameters 1 and 2 were adjusted to maximize the proportion of prolonged RR intervals within range. These constraints were used for prediction of prolonged RR in test data collected during the second hour. Results The mean prolonged event was 1.0 seconds in duration. Actual prolonged events were identified with a mean positive predictive value (PPV) of 80% in the test set. PPV was >80% in 36 of 74 patients. An average of 10.8 prolonged RR intervals per 60 minutes was correctly identified. Conclusions A method was developed to predict prolonged RR intervals using two parameters and prior statistical sampling for each patient. This or similar methodology may help improve cardiac imaging in many longstanding persistent AF patients. PMID:23998759

Prognostic value of cardiovascular magnetic resonance imaging measurements corrected for age and sex in idiopathic pulmonary arterial hypertension.

PubMed

Swift, Andrew J; Rajaram, Smitha; Campbell, Michael J; Hurdman, Judith; Thomas, Steve; Capener, Dave; Elliot, Charlie; Condliffe, Robin; Wild, Jim M; Kiely, David G

2014-01-01

There are limited data on the prognostic value of cardiovascular magnetic resonance measurements in idiopathic pulmonary arterial hypertension, with no studies investigating the impact of correction of cardiovascular magnetic resonance indices for age and sex on prognostic value. Consecutive patients with idiopathic pulmonary arterial hypertension underwent cardiovascular magnetic resonance imaging at 1.5T. Steady-state free precession cardiac volumes and mass measurements were corrected for age, sex, and body surface area according to reference data and prognostic significance assessed. A total of 80 patients with idiopathic pulmonary arterial hypertension were identified, and 23 patients died during the mean follow-up of 32±14 months. Corrected for age, sex, and body surface area, right ventricular end-systolic volume (P=0.004) strongly predicted mortality, independent of World Health Organization functional class, mean right atrial pressure, cardiac index, and mixed venous oxygen saturations. Consideration should be given to correcting cardiovascular magnetic resonance measures for age, sex, and body surface area, particularly given the changing demographics of patients with idiopathic pulmonary arterial hypertension. Corrected right ventricular end-systolic volume is a strong prognostic marker in idiopathic pulmonary arterial hypertension, independent of invasively derived measurements, mean right atrial pressure cardiac index, and mixed venous oxygen saturations.

Paroxysmal ventricular tachycardia and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism, chronic renal failure and elevation of prostate-specific antigen during acute myocardial infarction.

PubMed

Patanè, Salvatore; Marte, Filippo

2010-02-04

Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. Paroxysmal atrial fibrillation is a frequent complication of acute myocardial infarction. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including an increase in atrial fibrillation rate. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. Moreover chronic renal failure presents an increased arrhythmic risk. Apparently spurious result has been reported in a work about mean serum prostate-specific antigen (PSA) concentration during acute myocardial infarction with mean serum PSA concentration significantly lower on day 2 than either day 1 or day 3 and it has been reported that these preliminary results could reflect several factors, such as antiinfarctual treatment, reduced physical activity or an acute-phase response. We present a case of paroxysmal ventricular tachycardia and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism, chronic renal failure and elevation of serum PSA concentration in a 90-year-old Italian man during acute myocardial infarction. Also this case focuses attention on the importance of a correct evaluation of subclinical hyperthyroidism and of chronic renal failure. Moreover, our report also confirms previous findings and extends the evaluation of PSA during acute myocardial infarction. Copyright 2008 Elsevier Ireland Ltd. All rights reserved.

Rotors and the Dynamics of Cardiac Fibrillation

PubMed Central

Pandit, Sandeep V.; Jalife, José

2013-01-01

The objective of this article is to present a broad review on the role of cardiac electrical rotors and their accompanying spiral waves in the mechanism of cardiac fibrillation. At the outset, we present a brief historical overview regarding reentry, and then discuss the basic concepts and terminologies pertaining to rotors and their initiation. Thereafter, the intrinsic properties of rotors and spiral waves, including phase singularities, wavefront curvature and dominant frequency maps are discussed. The implications of rotor dynamics for the spatio-temporal organization of fibrillation, independent of the species being studied are touched upon next. The knowledge gained regarding the role of cardiac structure in the initiation and/or maintenance of rotors and the ionic bases of spiral waves in the last two decades, and its significance for drug therapy is reviewed subsequently. We conclude by looking at recent evidence suggesting that rotors are critical in sustaining both atrial and ventricular fibrillation (AF, VF) in the human heart, and its implications for treatment with radio-frequency ablation. PMID:23449547

Right Ventricular Sex Differences in Patients with Idiopathic Pulmonary Arterial Hypertension Characterised by Magnetic Resonance Imaging: Pair-Matched Case Controlled Study

PubMed Central

Swift, Andrew J.; Capener, Dave; Hammerton, Charlotte; Thomas, Steven M.; Elliot, Charlie; Condliffe, Robin; Wild, Jim M.; Kiely, David G.

2015-01-01

Purpose Sex differences exist in both the prevalence and survival of patients with idiopathic pulmonary arterial hypertension (IPAH). Men are less frequently affected by the condition but have worse outcome as compared to females. We sought to characterise the sex related differences in right ventricular remodelling in age matched male and female patients with IPAH using cardiac magnetic resonance imaging (MRI). Methods A case controlled pair-matched study was conducted with patients matched by age and sex. Steady state free precession (SSFP) MRI of the heart was performed at 1.5T. Cardiac volume, function and mass measurements were corrected for age, sex and BSA according to reference data. Results 40 age and sex matched patients with IPAH were identified. The mean age was 57 (SD 17) in both male and female cohorts. Men had proportionally lower right ventricular (RV) ejection fraction, RV stroke volume and LV stroke volume than females, p=0.028, p=0.007 and p=0.013, respectively. However, there was no significant difference in RV mass or haemodynamic indices of mPAP and PVR between males and females. Conclusion Male patients with IPAH have proportionally worse RV function despite similar afterload. We hypothesise that adaptive remodelling of the RV in response to increased afterload in IPAH is more effective in females. PMID:25996939

Reversible atrial fibrillation following Crotalinae envenomation.

PubMed

Quan, Dan; Zurcher, Kenneth

2017-01-01

Cardiotoxicity is a documented complication of Crotalinae envenomation. Reported cardiac complications following snake envenomation have included acute myocardial infarction, electrocardiogram abnormalities and arrhythmias. Few reports exist describing arrhythmia induced by viper envenomation and to our knowledge none describe arrhythmia induced by Crotalinae envenomation. This report concerns the first known case of atrial fibrillation precipitated by rattlesnake bite. A 73-year-old Caucasian man with a past medical history of hypertension, hyperlipidemia, type 1 diabetes mellitus, and a baseline first-degree atrioventricular block presented to the emergency department following a rattlesnake bite to his left lower leg. He developed pain and swelling in his left leg two-hour post-envenomation and subsequently received four vials of Crotalidae polyvalent immune fab (ovine). At three-hour post-envenomation following transfer to the intensive care unit, an electrocardiogram revealed new-onset atrial fibrillation. An amiodarone drip was started and the patient successfully converted to normal sinus rhythm approximately six hours after he was found to be in atrial fibrillation. A transthoracic echocardiogram revealed mild concentric left ventricular hypertrophy and an ejection fraction of 72%. He was discharged the following day with no hematological abnormalities and a baseline first-degree atrioventricular block. This is the first documented case of reversible atrial fibrillation precipitated by Crotalinae envenomation. In patients with pertinent risk factors for developing atrial fibrillation, physicians should be aware of the potential for this arrhythmia. Direct toxic effects of venom or structural and electrophysiological cardiovascular abnormalities may predispose snakebite patients to arrhythmia, warranting extended and attentive cardiac monitoring.

Amiodarone Versus Lidocaine for Pediatric Cardiac Arrest Due to Ventricular Arrhythmias: A Systematic Review.

PubMed

McBride, Mary E; Marino, Bradley S; Webster, Gregory; Lopez-Herce, Jesús; Ziegler, Carolyn P; De Caen, Allan R; Atkins, Dianne L

2017-02-01

We performed a systematic review as part of the International Liaison Committee on Resuscitation process to create a consensus on science statement regarding amiodarone or lidocaine during pediatric cardiac arrest for the 2015 International Liaison Committee on Resuscitation's Consensus on Science and Treatment Recommendations. Studies were identified from comprehensive searches in PubMed, Embase, and the Cochrane Library. Studies eligible for inclusion were randomized controlled and observational studies on the relative clinical effect of amiodarone or lidocaine in cardiac arrest. Studies addressing the clinical effect of amiodarone versus lidocaine were extracted and reviewed for inclusion and exclusion criteria by the reviewers. Studies were rigorously analyzed thereafter. We identified three articles addressing lidocaine versus amiodarone in cardiac arrest: 1) a prospective study assessing lidocaine versus amiodarone for refractory ventricular fibrillation in out-of-hospital adults; 2) an observational retrospective cohort study of inpatient pediatric patients with ventricular fibrillation or pulseless ventricular tachycardia who received lidocaine, amiodarone, neither or both; and 3) a prospective study of ventricular tachycardia with a pulse in adults. The first study showed a statistically significant improvement in survival to hospital admission with amiodarone (22.8% vs 12.0%; p = 0.009) and a lack of statistical difference for survival at discharge (p = 0.34). The second article demonstrated 44% return of spontaneous circulation for amiodarone and 64% for lidocaine (odds ratio, 2.02; 1.36-3.03) with no statistical difference for survival at hospital discharge. The third article demonstrated 48.3% arrhythmia termination for amiodarone versus 10.3% for lidocaine (p < 0.05). All were classified as lower quality studies without preference for one agent. The confidence in effect estimates is so low that International Liaison Committee on Resuscitation felt

Atrial fibrillation: effects beyond the atrium?

PubMed

Wijesurendra, Rohan S; Casadei, Barbara

2015-03-01

Atrial fibrillation (AF) is the most common sustained clinical arrhythmia and is associated with significant morbidity, mostly secondary to heart failure and stroke, and an estimated two-fold increase in premature death. Efforts to increase our understanding of AF and its complications have focused on unravelling the mechanisms of electrical and structural remodelling of the atrial myocardium. Yet, it is increasingly recognized that AF is more than an atrial disease, being associated with systemic inflammation, endothelial dysfunction, and adverse effects on the structure and function of the left ventricular myocardium that may be prognostically important. Here, we review the molecular and in vivo evidence that underpins current knowledge regarding the effects of human or experimental AF on the ventricular myocardium. Potential mechanisms are explored including diffuse ventricular fibrosis, focal myocardial scarring, and impaired myocardial perfusion and perfusion reserve. The complex relationship between AF, systemic inflammation, as well as endothelial/microvascular dysfunction and the effects of AF on ventricular calcium handling and oxidative stress are also addressed. Finally, consideration is given to the clinical implications of these observations and concepts, with particular reference to rate vs. rhythm control. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

MRI, volumetry, 1H spectroscopy, and cerebropetal blood flowmetry in childhood idiopathic anatomic megalencephaly.

PubMed

Koudijs, Suzanne M; van der Grond, Jeroen; Hoogendoorn, Mechteld L C; Hulshoff Pol, Hilleke E; Schnack, Hugo G; Witkamp, Theo D; Gooskens, Rob H J M; van Nieuwenhuizen, Onno; Braun, Kees P J

2006-08-01

To evaluate cerebral abnormalities in childhood idiopathic anatomic megalencephaly (MC) by means of different magnetic resonance (MR) modalities. MRI, volumetry, spectroscopy, and cerebropetal blood flowmetry were performed in six children with idiopathic anatomic MC, and seven volunteers. MRI revealed an increased ventricular system in five of six patients. A thalamic hamartoma was found in one patient and a Chiari I malformation was found in two. Volumetric analysis showed a disproportional increase of ventricular volume but normal subarachnoid cerebrospinal fluid (CSF) volume. Supratentorial volume was disproportionally increased compared to cerebellar volume. Intracranial volume correlated significantly with skull circumference. MR spectroscopy (MRS) N-acetyl aspartate/choline (NAA/Cho) peak ratios in WM were significantly higher in patients than in controls. Choline/creatine (Cho/Cr) peak ratios in WM were significantly lower in patients. Cortical gray matter (GM) MRS ratios were unaltered. Cerebropetal flow was increased in MC, possibly related to increased brain volume. This study reveals associated developmental anomalies for idiopathic anatomic MC. A relative ventriculomegaly was found, which should not be misinterpreted as true hydrocephalus. In contrast to metabolic MC, MRS showed no severe disturbances. Total intracranial volume is correlated to skull circumference and cerebropetal blood flow.

Right Ventricular Structure and Function Are Associated With Incident Atrial Fibrillation: MESA-RV Study (Multi-Ethnic Study of Atherosclerosis-Right Ventricle).

PubMed

Chatterjee, Neal A; Shah, Ravi V; Murthy, Venkatesh L; Praestgaard, Amy; Shah, Sanjiv J; Ventetuolo, Corey E; Barr, R Graham; Kronmal, Richard; Lima, Joao A C; Bluemke, David A; Jerosch-Herold, Michael; Alonso, Alvaro; Kawut, Steven M

2017-01-01

Right ventricular (RV) morphology has been associated with drivers of atrial fibrillation (AF) risk, including left ventricular and pulmonary pathology, systemic inflammation, and neurohormonal activation. The aim of this study was to investigate the association between RV morphology and risk of incident AF. We interpreted cardiac magnetic resonance imaging in 4204 participants free of clinical cardiovascular disease in the MESA (Multi-Ethnic Study of Atherosclerosis). Incident AF was determined using hospital discharge records, study electrocardiograms, and Medicare claims data. The study sample (n=3819) was 61±10 years old and 47% male with 47.2% current/former smokers. After adjustment for demographics and clinical factors, including incident heart failure, higher RV ejection fraction (hazard ratio, 1.16 per SD; 95% confidence interval, 1.03-1.32; P=0.02) and greater RV mass (hazard ratio, 1.25 per SD; 95% confidence interval, 1.08-1.44; P=0.002) were significantly associated with incident AF. After additional adjustment for the respective left ventricular parameter, higher RV ejection fraction remained significantly associated with incident AF (hazard ratio, 1.15 per SD; 95% confidence interval, 1.01-1.32; P=0.04), whereas the association was attenuated for RV mass (hazard ratio, 1.16 per SD; 95% confidence interval, 0.99-1.35; P=0.07). In a subset of patients with available spirometry (n=2540), higher RV ejection fraction and mass remained significantly associated with incident AF after additional adjustment for lung function (P=0.02 for both). Higher RV ejection fraction and greater RV mass were associated with an increased risk of AF in a multiethnic population free of clinical cardiovascular disease at baseline. © 2017 American Heart Association, Inc.

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.

Malignant ventricular arrhythmias in alcoholic cardiomyopathy.

PubMed

Guzzo-Merello, Gonzalo; Dominguez, Fernando; González-López, Esther; Cobo-Marcos, Marta; Gomez-Bueno, Manuel; Fernandez-Lozano, Ignacio; Millan, Isabel; Segovia, Javier; Alonso-Pulpon, Luis; Garcia-Pavia, Pablo

2015-11-15

Excessive alcohol consumption is a well-known aetiology of atrial arrhythmias but there is little information concerning the prevalence or incidence of malignant ventricular arrhythmias in alcoholic cardiomyopathy (ACM). This study sought to investigate incidence and predictive factors of ventricular arrhythmias in ACM. Retrospective observational study of the clinical characteristics and long-term arrhythmic events in 282 consecutive patients with ACM (94 individuals) and idiopathic dilated cardiomyopathy (IDCM) (188 individuals) evaluated between 1993 and 2011. During a median follow-up of 38months (IQR:12-77), 42 patients died and 79 underwent heart transplantation [31 (33%) with ACM vs 90 (48%) with IDCM; p=0.017]. A total of 37 (13%) patients [18 (19%) ACM vs 20 (11%) IDCM; p=0.048] suffered malignant ventricular arrhythmias. On multivariate analysis, left bundle branch block (LBBB) (OR 2.4; CI95%: 1.2-5; p=0.015) and alcoholic aetiology (OR 2.3; CI95%: 1.1-4.5; p=0.026) were the only independent predictors of malignant ventricular arrhythmic events. A total of 18 (19%) ACM patients experienced 20 malignant ventricular arrhythmic events (4 aborted SCD, 8 SCD and 8 appropriate ICD therapies). At baseline evaluation, the only independent predictor of malignant ventricular arrhythmias in ACM patients was LBBB (OR 11.2; CI95%: 2.6-50; p=0.001). No malignant ventricular arrhythmias were recorded during follow-up in ACM patients if left ventricular ejection fraction (LVEF) had increased or remained ≥40%. Malignant ventricular arrhythmias are more frequent in ACM than in IDCM. LBBB identifies ACM patients with increased risk of SCD. No malignant ventricular arrhythmias were found during follow-up in ACM patients when LVEF was ≥40%. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Idiopathic dilated cardiomyopathy: computerized anatomic study of relashionship between septal and free left ventricle wall.

PubMed

Juliani, Paulo Sérgio; Costa, Eder França da; Correia, Aristides Tadeu; Monteiro, Rosangela; Jatene, Fabio Biscegli

2014-01-01

A feature of dilated cardiomyopathy is the deformation of ventricular cavity, which contributes to systolic dysfunction. Few studies have evaluated this deformation bearing in mind ventricular regions and segments of the ventricle, which could reveal important details of the remodeling process, supporting a better understanding of its role in functional impairment and the development of new therapeutic strategies. To evaluate if, in basal, equatorial and apical regions, increased internal transverse perimeter of left ventricle in idiopathic dilated cardiomyopathy occurs proportionally between the septal and non-septal segment. We performed an anatomical study with 28 adult hearts from human cadavers. One group consisted of 18 hearts with idiopathic dilated cardiomyopathy and another group with 10 normal hearts. After lamination and left ventricle digital image capture, in three different regions (base, equator and apex), the transversal internal perimeter of left ventricle was divided into two segments: septal and not septal. These segments were measured by proper software. It was established an index of proportionality between these segments, called septal and non-septal segment index. Then we determined whether this index was the same in both groups. Among patients with normal hearts and idiopathic dilated cardiomyopathy, the index of proportionality between the two segments (septal and non-septal) showed no significant difference in the three regions analyzed. The comparison results of the indices NSS/SS among normal and enlarged hearts were respectively: in base 1.99 versus 1.86 (P=0.46), in equator 2.22 versus 2.18 (P=0.79) and in apex 2.96 versus 3.56 (P=0.11). In the idiopathic dilated cardiomyopathy, the transversal dilatation of left ventricular internal perimeter occurs proportionally between the segments corresponding to the septum and free wall at the basal, equatorial and apical regions of this chamber.

Idiopathic dilated cardiomyopathy: computerized anatomic study of relashionship between septal and free left ventricle wall

PubMed Central

Juliani, Paulo Sérgio; da Costa, Éder França; Correia, Aristides Tadeu; Monteiro, Rosangela; Jatene, Fabio Biscegli

2014-01-01

Introduction A feature of dilated cardiomyopathy is the deformation of ventricular cavity, which contributes to systolic dysfunction. Few studies have evaluated this deformation bearing in mind ventricular regions and segments of the ventricle, which could reveal important details of the remodeling process, supporting a better understanding of its role in functional impairment and the development of new therapeutic strategies. Objective To evaluate if, in basal, equatorial and apical regions, increased internal transverse perimeter of left ventricle in idiopathic dilated cardiomyopathy occurs proportionally between the septal and non-septal segment. Methods We performed an anatomical study with 28 adult hearts from human cadavers. One group consisted of 18 hearts with idiopathic dilated cardiomyopathy and another group with 10 normal hearts. After lamination and left ventricle digital image capture, in three different regions (base, equator and apex), the transversal internal perimeter of left ventricle was divided into two segments: septal and not septal. These segments were measured by proper software. It was established an index of proportionality between these segments, called septal and non-septal segment index. Then we determined whether this index was the same in both groups. Results Among patients with normal hearts and idiopathic dilated cardiomyopathy, the index of proportionality between the two segments (septal and non-septal) showed no significant difference in the three regions analyzed. The comparison results of the indices NSS/SS among normal and enlarged hearts were respectively: in base 1.99 versus 1.86 (P=0.46), in equator 2.22 versus 2.18 (P=0.79) and in apex 2.96 versus 3.56 (P=0.11). Conclusion In the idiopathic dilated cardiomyopathy, the transversal dilatation of left ventricular internal perimeter occurs proportionally between the segments corresponding to the septum and free wall at the basal, equatorial and apical regions of this chamber

Analysis of Morphological Characteristics and Origins of Idiopathic Premature Ventricular Contractions Under a 12-Lead Electrocardiogram in Children with Structurally Normal Hearts.

PubMed

Jiang, Jianbin; He, Yuee; Qiu, Huixian; Zhang, Yuanhai; Chu, Maoping; Li, Yuechun; Chen, Qi

2017-10-21

Up to 40% of healthy children have premature ventricular complexes or contractions (PVCs) detected with 24-hour Holter monitoring. We aimed to investigate the morphological characteristics and origins of idiopathic PVCs under a 12-lead electrocardiogram in children with structurally normal hearts. All asymptomatic monomorphic PVC patients with structurally normal hearts under 18 years of age were included in this retrospective study. Characteristics of PVCs in lead V 1 under a 12-lead electrocardiogram were classified as left bundle branch block (PVC-LBBB) or right bundle branch block (PVC-RBBB). According to limb leads, PVC-LBBB or PVC-RBBB was divided into: PVCs-LBBB type I; PVCs-LBBB type II; PVCs-RBBB type I; PVCs-RBBB type II; and PVCs-RBBB type III. Out of 178 PVC patients, 94 cases of PVCs-LBBB (PVCs-LBBB type I = 60; PVCs-LBBB type II = 34) and 84 cases of PVCs-RBBB (PVCs-RBBB type I = 3; PVCs-RBBB type II = 55; PVCs-RBBB type III = 26) were identified. The frequency of PVCs-LBBB type I increased with age and the frequency of PVCs-RBBB type II and III decreased with age. Among the children monitor tested, from 1 years old to 18 years old, PVCs originating from the left or right ventricular outflow tract gradually increased with age, while PVCs originating from the branch sources decreased with age.

Association of Fibroblast Growth Factor 23 With Atrial Fibrillation in Chronic Kidney Disease, From the Chronic Renal Insufficiency Cohort Study

PubMed Central

Mehta, Rupal; Cai, Xuan; Lee, Jungwha; Scialla, Julia J.; Bansal, Nisha; Sondheimer, James H.; Chen, Jing; Hamm, L. Lee; Ricardo, Ana C.; Navaneethan, Sankar D.; Deo, Rajat; Rahman, Mahboob; Feldman, Harold I.; Go, Alan S.; Isakova, Tamara; Wolf, Myles

2016-01-01

Importance Levels of fibroblast growth factor 23 (FGF23) are elevated in chronic kidney disease (CKD) and strongly associated with left ventricular hypertrophy, heart failure, and death. Whether FGF23 is an independent risk factor for atrial fibrillation in CKD is unknown. Objective To investigate the association of FGF23 with atrial fibrillation in CKD. Design, Setting, and Participants Prospective cohort study of 3876 individuals with mild to severe CKD who enrolled in the Chronic Renal Insufficiency Cohort Study between June 19, 2003, and September 3, 2008, and were followed up through March 31, 2013. Exposures Baseline plasma FGF23 levels. Main Outcomes and Measures Prevalent and incident atrial fibrillation. Results The study cohort comprised 3876 participants. Their mean (SD) age was 57.7 (11.0) years, and 44.8% (1736 of 3876) were female. Elevated FGF23 levels were independently associated with increased odds of prevalent atrial fibrillation (n = 660) after adjustment for cardiovascular and CKD-specific factors (odds ratio of highest vs lowest FGF23 quartile, 2.30; 95% CI, 1.69-3.13; P < .001 for linear trend across quartiles). During a median follow-up of 7.6 years (interquartile range, 6.3-8.6 years), 247 of the 3216 participants who were at risk developed incident atrial fibrillation (11.9 events per 1000 person-years). In fully adjusted models, elevated FGF23 was independently associated with increased risk of incident atrial fibrillation after adjustment for demographic, cardiovascular, and CKD-specific factors, and other markers of mineral metabolism (hazard ratio of highest vs lowest FGF23 quartile, 1.59; 95% CI, 1.00-2.53; P = .02 for linear trend across quartiles). The results were unchanged when further adjusted for ejection fraction, but individual adjustments for left ventricular mass index, left atrial area, and interim heart failure events partially attenuated the association of elevated FGF23 with incident atrial fibrillation. Conclusions and

Modified Maze Procedure for Atrial Fibrillation as an Adjunct to Elective Cardiac Surgery: Predictors of Mid-Term Recurrence and Echocardiographic Follow-Up

PubMed Central

Alamanni, Francesco; Veglia, Fabrizio; Galli, Claudia; Parolari, Alessandro; Zanobini, Marco

2015-01-01

The radiofrequency maze procedure achieves sinus rhythm in 45%–95% of patients treated for atrial fibrillation. This retrospective study evaluates mid-term results of the radiofrequency maze—performed concomitant to elective cardiac surgery—to determine sinus-rhythm predictive factors, and describes the evolution of patients' echocardiographic variables. From 2003 through 2011, 247 patients (mean age, 64 ± 9.5 yr) with structural heart disease (79.3% mitral disease) and atrial fibrillation underwent a concomitant radiofrequency modified maze procedure. Patients were monitored by 24-hour Holter at 3, 6, 12, and 24 months, then annually. Eighty-four mitral-valve patients underwent regular echocardiographic follow-up. Univariate and multivariate analysis for risk factors of maze failure were identified. The in-hospital mortality rate was 1.2%. During a median follow-up of 39.4 months, the late mortality rate was 3.6%, and pacemaker insertion was necessary in 26 patients (9.4%). Sinus rhythm was present in 63% of patients at the latest follow-up. Predictive factors for atrial fibrillation recurrence were arrhythmia duration (hazard ratio [HR]=1.296, P=0.045) and atrial fibrillation at hospital discharge (HR=2.03, P=0.019). The monopolar device favored maze success (HR=0.191, P <0.0001). Left atrial area and indexed left ventricular end-diastolic volume showed significant decrease both in sinus rhythm and atrial fibrillation patients. Early sinus rhythm conversion was associated with improved left ventricular ejection fraction. Concomitant radiofrequency maze procedure provided remarkable outcomes. Shorter preoperative atrial fibrillation duration, monopolar device use, and prompt treatment of arrhythmia recurrences increase the midterm success rate. Early sinus rhythm restoration seems to result in better left ventricular ejection fraction recovery. PMID:26413016

Choroidal fissure acts as an overflow device in cerebrospinal fluid drainage: morphological comparison between idiopathic and secondary normal-pressure hydrocephalus

PubMed Central

Yamada, Shigeki; Ishikawa, Masatsune; Iwamuro, Yasushi; Yamamoto, Kazuo

2016-01-01

To clarify the pathogenesis of two different types of adult-onset normal-pressure hydrocephalus (NPH), we investigated cerebrospinal fluid distribution on the high-field three-dimensional MRI. The subarachnoid spaces in secondary NPH were smaller than those in the controls, whereas those in idiopathic NPH were of similar size to the controls. In idiopathic NPH, however, the basal cistern and Sylvian fissure were enlarged in concurrence with ventricular enlargement towards the z-direction, but the convexity subarachnoid space was severely diminished. In this article, we provide evidence that the key cause of the disproportionate cerebrospinal fluid distribution in idiopathic NPH is the compensatory direct CSF communication between the inferior horn of the lateral ventricles and the ambient cistern at the choroidal fissure. In contrast, all parts of the subarachnoid spaces were equally and severely decreased in secondary NPH. Blockage of CSF drainage from the subarachnoid spaces could cause the omnidirectional ventricular enlargement in secondary NPH. PMID:27941913

Improving trend in ventricular fibrillation/pulseless ventricular tachycardia out-of-hospital cardiac arrest in Rochester, Minnesota: A 26-year observational study from 1991 to 2016.

PubMed

Okubo, Masashi; Atkinson, Elizabeth J; Hess, Erik P; White, Roger D

2017-11-01

Mortality from out-of-hospital cardiac arrest (OHCA) is characterized by substantial regional variation. The Institute of Medicine (IOM) recently recommended enhancing the capabilities of EMS systems to improve outcome. In this study, we analyzed the trend in outcome from ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) OHCA in Rochester, MN. Survival from these forms of arrest is commonly employed as a benchmark of Emergency Medical Services (EMS) system performance. Using a population-based Utstein-style registry in Rochester, MN where a first responder early defibrillation system is utilized, we evaluated outcome from all EMS-treated VF/pVT arrests and the subgroup of bystander-witnessed VF/pVT from 1991 to 2016. Outcome measurement was neurologically intact survival to discharge, defined as Cerebral Performance Category (CPC) 1 or 2. We divided the 26-year study into three periods: 1991-1997, 1998-2008, and 2009-2016, based on initiation of the first responder system of police officers in 1991 and fire-rescue personnel in 1998, and the latter period for comparison with our previous report in 2009. We observed 355 all VF/pVT arrests and 292 bystander-witnessed VF/pVT arrests between 1991 and 2016. In 2009-2016, neurologically intact survival to discharge from overall VF/pVT and bystander-witnessed VF/pVT increased to 53.7% and 65.2%, respectively, compared with 39.5% and 43.4% in 1991-1997. Using multivariable analysis, survival significantly increased in 2009-2016 among all VF/pVT arrests (adjusted OR, 3.10; 95% CI, 1.54-6.40) and bystander-witnessed VF/pVT (adjusted OR, 4.28; 95% CI, 2.01-9.50), compared with those in 1991-1997. We observed a significant improving secular trend in neurologically intact survival from VF/pVT cardiac arrests with a relatively high recent survival rate in this EMS System. Copyright © 2017 Elsevier B.V. All rights reserved.

Atrial fibrillation pearls and perils of management.

PubMed Central

Kudenchuk, P J

1996-01-01

Atrial fibrillation, a common arrhythmia, is responsible for considerable cardiovascular morbidity. Its management demands more than antiarrhythmic therapy alone, but must address the causes and consequences of the arrhythmia. Although remediable causes are infrequently found, a thorough search for associated heart disease or its risk factors results in better-informed patient management. Controlling the ventricular response and protecting from thromboembolic complications are important initial goals of therapy and may include the administration of aspirin in younger, low-risk patients. Older patients and those with risk factors for systemic embolism are not adequately protected from stroke complications by aspirin therapy alone. It remains controversial whether all high-risk patients should receive warfarin and at what intensity. Whether and how sinus rhythm should be restored and maintained poses the greatest therapeutic controversy for atrial fibrillation. The mortal risk of antiarrhythmic therapy is substantially greater in patients with evidence of heart failure. In such persons, the risks and benefits of maintaining normal sinus rhythm with antiarrhythmic medications should be weighted carefully. A definitive cure for atrial fibrillation remains elusive, but promising surgical and catheter ablation therapies are being developed. PMID:8686300

Minnesota Resuscitation Consortium's Advanced Perfusion and Reperfusion Cardiac Life Support Strategy for Out-of-Hospital Refractory Ventricular Fibrillation.

PubMed

Yannopoulos, Demetris; Bartos, Jason A; Martin, Cindy; Raveendran, Ganesh; Missov, Emil; Conterato, Marc; Frascone, R J; Trembley, Alexander; Sipprell, Kevin; John, Ranjit; George, Stephen; Carlson, Kathleen; Brunsvold, Melissa E; Garcia, Santiago; Aufderheide, Tom P

2016-06-13

In 2015, the Minnesota Resuscitation Consortium (MRC) implemented an advanced perfusion and reperfusion life support strategy designed to improve outcome for patients with out-of-hospital refractory ventricular fibrillation/ventricular tachycardia (VF/VT). We report the outcomes of the initial 3-month period of operations. Three emergency medical services systems serving the Minneapolis-St. Paul metro area participated in the protocol. Inclusion criteria included age 18 to 75 years, body habitus accommodating automated Lund University Cardiac Arrest System (LUCAS) cardiopulmonary resuscitation (CPR), and estimated transfer time from the scene to the cardiac catheterization laboratory of ≤30 minutes. Exclusion criteria included known terminal illness, Do Not Resuscitate/Do Not Intubate status, traumatic arrest, and significant bleeding. Refractory VF/VT arrest was defined as failure to achieve sustained return of spontaneous circulation after treatment with 3 direct current shocks and administration of 300 mg of intravenous/intraosseous amiodarone. Patients were transported to the University of Minnesota, where emergent advanced perfusion strategies (extracorporeal membrane oxygenation; ECMO), followed by coronary angiography and primary coronary intervention (PCI), were performed, when appropriate. Over the first 3 months of the protocol, 27 patients were transported with ongoing mechanical CPR. Of these, 18 patients met the inclusion and exclusion criteria. ECMO was placed in 83%. Seventy-eight percent of patients had significant coronary artery disease with a high degree of complexity and 67% received PCI. Seventy-eight percent of patients survived to hospital admission and 55% (10 of 18) survived to hospital discharge, with 50% (9 of 18) achieving good neurological function (cerebral performance categories 1 and 2). No significant ECMO-related complications were encountered. The MRC refractory VF/VT protocol is feasible and led to a high functionally

Comparison of CSF Distribution between Idiopathic Normal Pressure Hydrocephalus and Alzheimer Disease.

PubMed

Yamada, S; Ishikawa, M; Yamamoto, K

2016-07-01

CSF volumes in the basal cistern and Sylvian fissure are increased in both idiopathic normal pressure hydrocephalus and Alzheimer disease, though the differences in these volumes in idiopathic normal pressure hydrocephalus and Alzheimer disease have not been well-described. Using CSF segmentation and volume quantification, we compared the distribution of CSF in idiopathic normal pressure hydrocephalus and Alzheimer disease. CSF volumes were extracted from T2-weighted 3D spin-echo sequences on 3T MR imaging and quantified semi-automatically. We compared the volumes and ratios of the ventricles and subarachnoid spaces after classification in 30 patients diagnosed with idiopathic normal pressure hydrocephalus, 10 with concurrent idiopathic normal pressure hydrocephalus and Alzheimer disease, 18 with Alzheimer disease, and 26 control subjects 60 years of age or older. Brain to ventricle ratios at the anterior and posterior commissure levels and 3D volumetric convexity cistern to ventricle ratios were useful indices for the differential diagnosis of idiopathic normal pressure hydrocephalus or idiopathic normal pressure hydrocephalus with Alzheimer disease from Alzheimer disease, similar to the z-Evans index and callosal angle. The most distinctive characteristics of the CSF distribution in idiopathic normal pressure hydrocephalus were small convexity subarachnoid spaces and the large volume of the basal cistern and Sylvian fissure. The distribution of the subarachnoid spaces in the idiopathic normal pressure hydrocephalus with Alzheimer disease group was the most deformed among these 3 groups, though the mean ventricular volume of the idiopathic normal pressure hydrocephalus with Alzheimer disease group was intermediate between that of the idiopathic normal pressure hydrocephalus and Alzheimer disease groups. The z-axial expansion of the lateral ventricle and compression of the brain just above the ventricle were the common findings in the parameters for differentiating

Relationship between diastolic ventricular dysfunction and subclinical sleep-disordered breathing in atrial fibrillation ablation candidates.

PubMed

Kaitani, Kazuaki; Kondo, Hirokazu; Hanazawa, Koji; Onishi, Naoaki; Hayama, Yukiko; Tsujimura, Akira; Kuroda, Maiko; Nishimura, Shunsuke; Yoshikawa, Yusuke; Takahashi, Yusuke; Amano, Masashi; Imamura, Sari; Tamaki, Yodo; Enomoto, Soichiro; Miyake, Makoto; Tamura, Toshihiro; Motooka, Makoto; Izumi, Chisato; Nakagawa, Yoshihisa

2016-07-01

Sleep-disordered breathing (SDB) is recognized as a primary factor or mediator of atrial fibrillation (AF). We hypothesized that the severity of SDB among AF ablation candidates would be associated with left ventricular diastolic dysfunction (LVDD) even for subclinical SDB. A total of 246 patients hospitalized for initial pulmonary vein isolation (PVI) were analyzed. Known SDB cases were excluded. We measured the oxygen desaturation index (ODI) by pulse oximetry overnight as an indicator of SDB, and classified SDB severity by 3 % ODI as normal (ODI < 5 events/h), mild (ODI ≤ 5 to <15 events/h), or moderate-to-severe (ODI ≥15 events/h). The LVDD was assessed by echocardiography using combined categories with tissue Doppler imaging and left atrial (LA) volume measurement. Among the participants, 42 patients (17.1 %) had LVDD. The prevalence of LVDD increased with the SDB severity from 8.6 % (normal) to 12.7 % (mild) to 40.0 % (moderate-to-severe SDB) (p < 0.0001). In the multivariate logistic regression analysis, the odds ratio of having LVDD in the moderate-to-severe SDB group (ODI ≥ 15) vs. normal group (ODI < 5) was 5.96 (95 % CI, 2.10-19.00, P = 0.006). The presence of moderate-to-severe SDB in AF ablation candidates adversely affected LV diastolic function even during a subclinical state of SDB.

Ventricular arrhythmias and sudden cardiac arrest in Takotsubo cardiomyopathy: Incidence, predictive factors, and clinical implications.

PubMed

Jesel, Laurence; Berthon, Charlotte; Messas, Nathan; Lim, Han S; Girardey, Mélanie; Marzak, Halim; Marchandot, Benjamin; Trinh, Annie; Ohlmann, Patrick; Morel, Olivier

2018-04-06

Takotsubo cardiomyopathy (TTC) is a stress-related transient cardiomyopathy. Life-threatening arrhythmias (LTA) can occur and worsen prognosis. The purpose of this study was to assess the incidence and outcome of LTA in TTC, as well as its predictive factors and clinical implications. We studied 214 consecutive cases of TTC over 8 years. The study cohort was divided into 2 groups: those with LTA (LTA group) and those without (non-LTA group). LTA was defined as ventricular tachycardia, ventricular fibrillation, or cardiac arrest. LTA occurred in 10.7% of patients mainly in the first 24 hours of hospitalization: ventricular tachycardia (n = 2), ventricular fibrillation (n = 11), cardiac arrest (n = 10: 5 asystole, 3 complete heart block, and 2 sinoatrial block). LTA were associated with lower left ventricular ejection fraction (LVEF) and a high rate of conduction disturbances. In-hospital (39.1% vs 8.9%; P < .001) and 1-year mortality (47.8% vs 14.1%; P < .001) rates were significantly increased in the LTA group. LVEF and QRS duration >105 ms were independent predictors of LTA. In cases where a device was implanted, conduction disturbances persisted after the index event despite complete recovery of LVEF. There was no ventricular arrhythmia recurrence during follow-up. LTA occur early in patients presenting with TTC and is associated with significantly worse short- and long-term prognosis. Left ventricular impairment and QRS duration >105 ms are independent predictors of LTA. Ventricular arrhythmias occurred in the acute phase without further recurrence recorded in hospital survivors, whereas severe conduction disorders persisted during long-term follow-up. These findings may have implications on the choice of device therapy for this specific patient subgroup. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Ventricular Arrhythmias in the North American Multidisciplinary Study of ARVC

PubMed Central

Link, Mark S.; Laidlaw, Douglas; Polonsky, Bronislava; Zareba, Wojciech; McNitt, Scott; Gear, Kathleen; Marcus, Frank; Mark Estes, NA

2015-01-01

BACKGROUND Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with sudden cardiac death. However, the selection of patients for implanted cardioverter-defibrillators (ICDs), as well as programming of the ICD, is unclear. OBJECTIVES The objective of this study was to identify predictors, characteristics, and treatment of ventricular arrhythmias in patients with ARVC. METHODS The Multidisciplinary Study of Right Ventricular Cardiomyopathy established the North American ARVC Registry and enrolled patients with a diagnosis of ARVC. Patients were followed prospectively. RESULTS Of 137 patients enrolled, 108 received ICDs. Forty-eight patients had 502 sustained episodes of ventricular arrhythmias, including 489 that were monomorphic and 13 that were polymorphic. In the patients with ICDs, independent predictors of ventricular arrhythmias in follow-up included spontaneous sustained ventricular arrhythmias before ICD implantation and T-wave inversions inferiorly. The only independent predictor for life-threatening arrhythmias, defined as sustained ventricular tachycardia (VT) ≥240 beats/min or ventricular fibrillation, was a younger age at enrollment. Anti-tachycardia pacing (ATP), independent of the cycle length of the VT, was successful in terminating 92% of VT episodes. CONCLUSIONS In the North American ARVC Registry, the majority of ventricular arrhythmias in follow-up are monomorphic. Risk factors for ventricular arrhythmias were spontaneous ventricular arrhythmias before enrollment and a younger age at ICD implantation. ATP is highly successful in terminating VT, and all ICDs should be programmed for ATP, even for rapid VT. PMID:25011714

Time of Occurrence and Duration of Atrial Fibrillation Following Coronary Artery Bypass Grafting.

PubMed

Avdic, Sevleta; Osmanovic, Enes; Kadric, Nedzad; Mujanovic, Emir; Ibisevic, Merima; Avdic, Azra

2016-04-01

Dilatation of the left atrium and left ventricular diastolic dysfunction (DDLV) according to recent studies has significance in the occurrence of postoperative atrial fibrillation (AF), stroke and death. Authors of some studies found no relationship between these parameters and atrial fibrillation. this study is to determine the time of occurrence and duration of atrial fibrillation in patients after surgical revascularization (CABG) due to the presence of left ventricular diastolic dysfunction and left atrium dilatation and identify the most significant predictors of incident AF. Prospective study included 116 patients undergoing surgical myocardial revascularization followed from admission to discharge. The study was conducted at the Special Hospital "Heart Center BH" Tuzla for a period of one year (March 2011/2012 g.). For all patients was performed preoperative ultrasound examination, especially parameters of diastolic function of the left ventricle and left atrium volume index (LAVi), as the best parameter sized left atrium, and the postoperative occurrence of certain AF and day occurrence, duration in hours, the number of attacks. To assess whether an event occurred or not was used logistic regression, and the effect of time on the event of interest is analyzed by Cox 's regression hazard parallel. 75.9 % of patients had DDLV, and 91.4 % were hypertensives, 12.9 % from the previous stroke (ICV) and 42.2 % diabetics (DM), 14 % with COPD. The average age of patients was 61.41 ± 4.69 years. In both groups was 32.8 % women and 67.2 % men. LAVi preoperative values were significantly higher as DDLV greater degree. In patients with DDLV and higher values LAVi risk of AF is higher, the greater the length of AF and significantly higher number of attacks FA. Early occurrence of atrial fibrillation and its longer duration in function with increasing LAVi a marked increase in the value LAVi have the greatest hazard for the early appearance of atrial fibrillation. As a

NASA's First Atrial Fibrillation Case - Deke Slayton

NASA Technical Reports Server (NTRS)

Tarver, William J.

2010-01-01

Concerns about heart dysrhythmia have been present since the earliest days of the US manned space program. While information about an astronaut's health is general kept private, one of the original seven American astronaut's health status was played out in a very public forum. Donald "Deke" Slayton was removed from the second manned space flight when it was discovered he had idiopathic atrial fibrillation. Referencing the original medical documents, details of how this was discovered and managed from the medical perspective will be reviewed. This is NASA's first heart dysrhythmia case in an astronaut and it proves quite interesting when placed in historic perspective.

Atrial contribution to ventricular filling in mitral stenosis.

PubMed

Meisner, J S; Keren, G; Pajaro, O E; Mani, A; Strom, J A; Frater, R W; Laniado, S; Yellin, E L

1991-10-01

The importance of the contribution of atrial systole to ventricular filling in mitral stenosis is controversial. The cause of reduced cardiac output following the onset of atrial fibrillation may be due to an increased heart rate, a loss of booster pump function, or both. We studied the atrial contribution to filling under a variety of conditions by combining noninvasive studies of patients with computer modeling. Thirty patients in sinus rhythm with mild-to-severe stenosis were studied with two-dimensional and Doppler echocardiography for measurement of mitral flow velocity and mitral valve area (MVA). The mean +/- SD atrial contribution to left ventricular filling volume was 18 +/- 10% and varied inversely with mitral resistance. Patients with mild mitral stenosis (MVA, 1.8 +/- 0.7 cm2) and severe mitral stenosis (MVA, 0.9 +/- 0.2 cm2) had atrial contributions of 29 +/- 4% and 9 +/- 5%, respectively. The pathophysiological mechanisms responsible for these trends were further investigated by the computer model. In modeled severe mitral stenosis, increasing heart rate from 75 to 150 beats/min caused an increase of 5.2 mm Hg in mean left atrial pressure, whereas loss of atrial contraction at a heart rate of 150 beats/min caused only a 1.3 mm Hg increase. The atrial booster pump contributes less to ventricular filling in mitral stenosis than in the normal heart, and the loss of atrial pump function is less important than the effect of increasing heart rate as the cause of decompensation during atrial fibrillation.

Dronedarone: a novel antiarrhythmic agent for the treatment of atrial fibrillation.

PubMed

Duray, Gabor Z; Ehrlich, Joachim R; Hohnloser, Stefan H

2010-01-01

To describe the electrophysiological profile and the clinical portfolio of dronedarone, a new multichannel-blocking antiarrhythmic drug developed for the treatment of atrial fibrillation. Dronedarone is a derivative of amiodarone that is free of iodine and less lipophilic. The drug has - as its predecessor - multichannel-blocking efficacy and in addition vasodilating effects. It reduces the incidence of ventricular fibrillation in several experimental models. Dronedarone has undergone thorough clinical evaluation in various patient populations. In two large trials, the drug was shown to postpone the recurrence of atrial fibrillation after cardioversion relative to placebo. In a trial in unstable heart failure patients, there was excess mortality in the dronedarone arm. This trial was stopped prematurely and prompted the conduct of a large outcome study. The ATHENA trial demonstrated a significant reduction in cardiovascular hospitalizations and death in atrial fibrillation patients randomly assigned to receive dronedarone or placebo. This large trial in more than 4600 patients revealed no signs of excess mortality or morbidity in patients receiving dronedarone. On the basis of the results of five international, multicenter, randomized clinical trials involving nearly 6300 patients, dronedarone was approved by the FDA for treatment of nonpermanent atrial fibrillation to reduce the risk of cardiovascular hospitalization.

Electrocardiogram frequency change by extracorporeal blood perfusion in a swine ventricular fibrillation model

PubMed Central

2013-01-01

Background Extracorporeal cardiopulmonary resuscitation (ECPR) refers to the application of extracorporeal blood circulation with oxygenation as a resuscitation tool. The objective of this study is to observe the frequency component changes in the electrocardiogram (ECG) by ECPR during prolonged ventricular fibrillation (VF). Methods Six swine were prepared as a VF model. Extracorporeal blood circulation with a pulsatile blood pump and oxygenator was set up for the model. ECG signals were measured for 13 min during VF and analyzed using frequency analysis methods. The median frequency (MF), dominant frequency (DF), and amplitude spectrum area (AMSA) were calculated from a spectrogram obtained using short-time Fourier transform (STFT). Results MF decreased from 11 Hz at the start to 9 Hz at 2 min after VF and then increased to 11 Hz at 4.5 min after VF. DF started at 7 Hz and increased to 11 Hz within the first min and decreased to 9 Hz at 2 min, then increased to 12 Hz at 4.5 min after VF. Both frequency components decreased gradually from 4.5 min until 10 min after VF. After the oxygenated blood perfusion was initiated, both MF and DF increased remarkably and exceeded 12 and 14 Hz, respectively. Similarly, AMSA decreased gradually for the first 10 min, but increased remarkably and varied beyond 13 mV∙Hz after the oxygenated blood supply started. Remarkable frequency increases in ECG due to the oxygenated blood perfusion during ECPR were observed in the swine VF model. Conclusions The ECG frequency analysis during ECPR can give the resuscitation provider important information about the cardiac perfusion status and the appropriateness of the ECPR setup as well as the prediction of defibrillation success. PMID:24274395

Arrhythmogenic Mechanisms in a Mouse Model of Catecholaminergic Polymorphic Ventricular Tachycardia

PubMed Central

Cerrone, Marina; Noujaim, Sami F.; Tolkacheva, Elena G.; Talkachou, Arkadzi; O’Connell, Ryan; Berenfeld, Omer; Anumonwo, Justus; Pandit, Sandeep V.; Vikstrom, Karen; Napolitano, Carlo; Priori, Silvia G.; Jalife, José

2008-01-01

Catecholaminergic polymorphic ventricular tachycardia (VT) is a lethal familial disease characterized by bidirectional VT, polymorphic VT, and ventricular fibrillation. Catecholaminergic polymorphic VT is caused by enhanced Ca2+ release through defective ryanodine receptor (RyR2) channels. We used epicardial and endocardial optical mapping, chemical subendocardial ablation with Lugol’s solution, and patch clamping in a knockin (RyR2/RyR2R4496C) mouse model to investigate the arrhythmogenic mechanisms in catecholaminergic polymorphic VT. In isolated hearts, spontaneous ventricular arrhythmias occurred in 54% of 13 RyR2/RyR2R4496C and in 9% of 11 wild-type (P=0.03) littermates perfused with Ca2+ and isoproterenol; 66% of 12 RyR2/RyR2R4496C and 20% of 10 wild-type hearts perfused with caffeine and epinephrine showed arrhythmias (P=0.04). Epicardial mapping showed that monomorphic VT, bidirectional VT, and polymorphic VT manifested as concentric epicardial breakthrough patterns, suggesting a focal origin in the His–Purkinje networks of either or both ventricles. Monomorphic VT was clearly unifocal, whereas bidirectional VT was bifocal. Polymorphic VT was initially multifocal but eventually became reentrant and degenerated into ventricular fibrillation. Endocardial mapping confirmed the Purkinje fiber origin of the focal arrhythmias. Chemical ablation of the right ventricular endocardial cavity with Lugol’s solution induced complete right bundle branch block and converted the bidirectional VT into monomorphic VT in 4 anesthetized RyR2/RyR2R4496C mice. Under current clamp, single Purkinje cells from RyR2/RyR2R4496C mouse hearts generated delayed afterdepolarization–induced triggered activity at lower frequencies and level of adrenergic stimulation than wild-type. Overall, the data demonstrate that the His–Purkinje system is an important source of focal arrhythmias in catecholaminergic polymorphic VT. PMID:17872467

Adverse ventricular-ventricular interactions in right ventricular pressure load: Insights from pediatric pulmonary hypertension versus pulmonary stenosis.

PubMed

Driessen, Mieke M P; Hui, Wei; Bijnens, Bart H; Dragulescu, Andreea; Mertens, Luc; Meijboom, Folkert J; Friedberg, Mark K

2016-06-01

Right ventricular (RV) pressure overload has a vastly different clinical course in children with idiopathic pulmonary arterial hypertension (iPAH) than in children with pulmonary stenosis (PS). While RV function is well recognized as a key prognostic factor in iPAH, adverse ventricular-ventricular interactions and LV dysfunction are less well characterized and the pathophysiology is incompletely understood. We compared ventricular-ventricular interactions as hypothesized drivers of biventricular dysfunction in pediatric iPAH versus PS Eighteen iPAH, 16 PS patients and 18 age- and size-matched controls were retrospectively studied. Cardiac cycle events were measured by M-mode and Doppler echocardiography. Measurements were compared between groups using ANOVA with post hoc Dunnet's or ANCOVA including RV systolic pressure (RVSP; iPAH 96.8 ± 25.4 mmHg vs. PS 75.4 ± 18.9 mmHg; P = 0.011) as a covariate. RV-free wall thickening was prolonged in iPAH versus PS, extending beyond pulmonary valve closure (638 ± 76 msec vs. 562 ± 76 msec vs. 473 ± 59 msec controls). LV and RV isovolumetric relaxation were prolonged in iPAH (P < 0.001; LV 102.8 ± 24.1 msec vs. 63.1 ± 13.7 msec; RV 95 [61-165] vs. 28 [0-43]), associated with adverse septal kinetics; characterized by rightward displacement in early systole and leftward displacement in late RV systole (i.e., early LV diastole). Early LV diastolic filling was decreased in iPAH (73 ± 15.9 vs. PS 87.4 ± 14.4 vs. controls 95.8 ± 12.5 cm/sec; P = 0.004). Prolonged RVFW thickening, prolonged RVFW isovolumetric times, and profound septal dyskinesia are associated with interventricular mechanical discoordination and decreased early LV filling in pediatric iPAH much more than PS These adverse mechanics affect systolic and diastolic biventricular efficiency in iPAH and may form the basis for worse clinical outcomes. We used clinically derived data to study the pathophysiology of ventricular-ventricular

Spatial-temporal filter effect in a computer model study of ventricular fibrillation.

PubMed

Nowak, Claudia N; Fischer, Gerald; Wieser, Leonhard; Tilg, Bernhard; Neurauter, Andreas; Strohmenger, Hans U

2008-08-01

Prediction of countershock success from ventricular fibrillation (VF) ECG is a major challenge in critical care medicine. Recent findings indicate that stable, high frequency mother rotors are one possible mechanism maintaining VF. A computer model study was performed to investigate how epicardiac sources are reflected in the ECG. In the cardiac tissues of two computer models - a model with cubic geometry and a simplified torso model with a left ventricle - a mother rotor was induced by increasing the potassium rectifier current. On the epicardium, the dominant frequency (DF) map revealed a constant DF of 23 Hz (cubic model) and 24.4 Hz (torso model) in the region of the mother rotor, respectively. A sharp drop of frequency (3-18 Hz in the cubic model and 12.4-18 Hz in the torso model) occurred in the surrounding epicardial tissue of chaotic fibrillatory conduction. While no organized pattern was observable on the body surface of the cubic model, the mother rotor frequency can be identified in the anterior surface of the torso model because of the chosen position of the mother rotor in the ventricle (shortest distance to the body surface). Nevertheless, the DFs were damped on the body surfaces of both models (4.6-8.5 Hz in the cubic model and 14.4-16.4 Hz in the torso model). Thus, it was shown in this computer model study that wave propagation transforms the spatial low pass filtering of the thorax into a temporal low pass. In contrast to the resistive-capacitive low pass filter formed by the tissue, this spatial-temporal low pass filter becomes effective at low frequencies (tens of Hertz). This effect damps the high frequency components arising from the heart and it hampers a direct observation of rapid, organized sources of VF in the ECGs, when in an emergency case an artifact-free recording is not possible.

HeartSaver: a mobile cardiac monitoring system for auto-detection of atrial fibrillation, myocardial infarction, and atrio-ventricular block.

PubMed

Sankari, Ziad; Adeli, Hojjat

2011-04-01

A mobile medical device, dubbed HeartSaver, is developed for real-time monitoring of a patient's electrocardiogram (ECG) and automatic detection of several cardiac pathologies, including atrial fibrillation, myocardial infarction and atrio-ventricular block. HeartSaver is based on adroit integration of four different modern technologies: electronics, wireless communication, computer, and information technologies in the service of medicine. The physical device consists of four modules: sensor and ECG processing unit, a microcontroller, a link between the microcontroller and the cell phone, and mobile software associated with the system. HeartSaver includes automated cardiac pathology detection algorithms. These algorithms are simple enough to be implemented on a low-cost, limited-power microcontroller but powerful enough to detect the relevant cardiac pathologies. When an abnormality is detected, the microcontroller sends a signal to a cell phone. This operation triggers an application software on the cell phone that sends a text message transmitting information about patient's physiological condition and location promptly to a physician or a guardian. HeartSaver can be used by millions of cardiac patients with the potential to transform the cardiac diagnosis, care, and treatment and save thousands of lives. Copyright © 2011 Elsevier Ltd. All rights reserved.

Long-Term Clinical Outcome of Arrhythmogenic Right Ventricular Cardiomyopathy in Individuals With a p.S358L Mutation in TMEM43 Following Implantable Cardioverter Defibrillator Therapy.

PubMed

Hodgkinson, Kathleen A; Howes, A J; Boland, Paul; Shen, Xiou Seegar; Stuckless, Susan; Young, Terry-Lynn; Curtis, Fiona; Collier, Ashley; Parfrey, Patrick S; Connors, Sean P

2016-03-01

We previously showed a survival benefit of the implantable cardioverter defibrillator (ICD) in males with arrhythmogenic right ventricular cardiomyopathy caused by a p.S358L mutation in TMEM43. We present long-term data (median follow-up 8.5 years) after ICD for primary (PP) and secondary prophylaxis in males and females, determine whether ICD discharges for ventricular tachycardia/ventricular fibrillation were equivalent to an aborted death, and assess relevant clinical predictors. We studied 24 multiplex families segregating an autosomal dominant p.S358L mutation in TMEM43. We compared survival in 148 mutation carriers with an ICD to 148 controls matched for age, sex, disease status, and family. Of 80 male mutation carriers with ICDs (median age at implantation 31 years), 61 (76%) were for PP; of 68 females (median age at implantation 43 years), 66 (97%) were for PP. In males, irrespective of indication, survival was better in the ICD groups compared with control groups (relative risk 9.3 [95% confidence interval 3.3-26] for PP and 9.7 [95% confidence interval 3.2-29.6] for secondary prophylaxis). For PP females, the relative risk was 3.6 (95% confidence interval 1.3-9.5). ICD discharge-free survival for ventricular tachycardia/ventricular fibrillation ≥ 240 beats per minute was equivalent to the control survival rate. Ectopy (≥ 1000 premature ventricular complexes/24 hours) was the only independent clinical predictor of ICD discharge in males, and no predictor was identified in females. ICD therapy is indicated for PP in postpubertal males and in females ≥ 30 years with the p.S358L TMEM43 mutation. ICD termination of rapid ventricular tachycardia/ventricular fibrillation can reasonably be considered an aborted death. © 2016 American Heart Association, Inc.

Preoperative atrial fibrillation increases risk of thromboembolic events after left ventricular assist device implantation.

PubMed

Stulak, John M; Deo, Salil; Schirger, John; Aaronson, Keith D; Park, Soon J; Joyce, Lyle D; Daly, Richard C; Pagani, Francis D

2013-12-01

Because no series has specifically analyzed the impact of preoperative atrial fibrillation (AF) on patients already at higher risk of thromboembolism after implantation of a left ventricular assist device (LVAD), we review our experience with these patients. Between July 2003 and September 2011, 389 patients (308 male) underwent implantation of a continuous flow LVAD at University of Michigan Hospital and Mayo Clinic. Median age at implant was 60 years (range, 18 to 79 years). Preoperative AF was present in 120 patients (31%). Outcomes were analyzed for the association of preoperative AF and postoperative thromboembolic (TE) events defined as stroke, transient ischemic attack, hemolysis, or pump thrombosis. Thromboembolic events occurring within the first 30 days were not counted. One hundred thirty-eight TEs events occurred in 97/389 patients (25%) for an event rate of 0.31 TE events/patient-years of support. Freedom from a TE event in patients with preoperative AF was 62% at 1 year and 46% at 2 years compared with 79% and 72% at 1 and 2 years, respectively, in patients without preoperative AF (p < 0.001). Median survival was 10 months (maximum 7.2 years, total 439 patient-years). Preoperative AF did not decrease late survival at 1 and 2 years after LVAD implant (preop AF: 85% and 70% versus no preop AF: 82% and 70%, respectively; p = 0.55). Patients with preoperative AF have a lower freedom from TE events after LVAD implant. While overall late survival was not significantly reduced in these patients, refinement in anticoagulation strategies after VAD implant may be required. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Novel ion channel targets in atrial fibrillation.

PubMed

Hancox, Jules C; James, Andrew F; Marrion, Neil V; Zhang, Henggui; Thomas, Dierk

2016-08-01

Atrial fibrillation (AF) is the most common arrhythmia in humans. It is progressive and the development of electrical and structural remodeling makes early intervention desirable. Existing antiarrhythmic pharmacological approaches are not always effective and can produce unwanted side effects. Additional atrial-selective antiarrhythmic strategies are therefore desirable. Evidence for three novel ion channel atrial-selective therapeutic targets is evaluated: atrial-selective fast sodium channel current (INa) inhibition; small conductance calcium-activated potassium (SK) channels; and two-pore (K2P) potassium channels. Data from animal models support atrial-ventricular differences in INa kinetics and also suggest atrial-ventricular differences in sodium channel β subunit expression. Further work is required to determine whether intrinsic atrial-ventricular differences in human INa exist or whether functional differences occur due to distinct atrial and ventricular action and resting potentials. SK and K2P channels (particularly K2P 3.1) offer potentially attractive atrial-selective targets. Work is needed to identify the underlying basis of SK current that contributes to (patho)physiological atrial repolarization and settings in which SK inhibition is anti- versus pro-arrhythmic. Although K2P3.1 appears to be a promising target with comparatively selective drugs for experimental use, a lack of selective pharmacology hinders evaluation of other K2P channels as potential atrial-selective targets.

Prevalence of lateral ventricle asymmetry in brain MRI studies of neurologically normal dogs and dogs with idiopathic epilepsy.

PubMed

Pivetta, Mauro; De Risio, Luisa; Newton, Richard; Dennis, Ruth

2013-01-01

Asymmetry of the cerebral lateral ventricles is a common finding in cross-sectional imaging of otherwise normal canine brains and has been assumed to be incidental. The purpose of this retrospective study was to compare the prevalence of ventricular asymmetry in brain MRI studies of normal dogs and dogs with idiopathic epilepsy. Brain MRI archives were searched for 100 neurologically normal dogs (Group 1) and 100 dogs with idiopathic epilepsy (Group 2). For each dog, asymmetry of the lateral ventricles was subjectively classified as absent, mild, moderate, and severe based on a consensus of two observers who were unaware of group status. Ventricular areas were measured from transverse T1W images at the level of the interthalamic adhesion. An asymmetry ratio was calculated as the ratio of the larger to smaller ventricular transverse area. There was excellent agreement between subjective assessments of ventricular asymmetry and quantitative assessments using asymmetry ratios (k = 0.995). The prevalence of asymmetry was 38% in Group 1 dogs and 44% in Group 2 dogs. Assymmetry was scored as mild in the majority of Group 2 dogs. There was no significant association between presence/absence and degree of ventricular asymmetry vs. dog group, age, gender, or skull conformation. Findings from the current study supported previously published assumptions that asymmetry of the lateral cerebral ventricles is an incidental finding in MRI studies of the canine brain. © 2013 Veterinary Radiology & Ultrasound.

Comparison of Quantitative Characteristics of Early Post-resuscitation EEG Between Asphyxial and Ventricular Fibrillation Cardiac Arrest in Rats.

PubMed

Chen, Bihua; Chen, Gang; Dai, Chenxi; Wang, Pei; Zhang, Lei; Huang, Yuanyuan; Li, Yongqin

2018-04-01

Quantitative electroencephalogram (EEG) analysis has shown promising results in studying brain injury and functional recovery after cardiac arrest (CA). However, whether the quantitative characteristics of EEG, as potential indicators of neurological prognosis, are influenced by CA causes is unknown. The purpose of this study was designed to compare the quantitative characteristics of early post-resuscitation EEG between asphyxial CA (ACA) and ventricular fibrillation CA (VFCA) in rats. Thirty-two Sprague-Dawley rats of both sexes were randomized into either ACA or VFCA group. Cardiopulmonary resuscitation was initiated after 5-min untreated CA. Characteristics of early post-resuscitation EEG were compared, and the relationships between quantitative EEG features and neurological outcomes were investigated. Compared with VFCA, serum level of S100B, neurological deficit score and brain histopathologic damage score were dramatically higher in the ACA group. Quantitative measures of EEG, including onset time of EEG burst, time to normal trace, burst suppression ratio, and information quantity, were significantly lower for CA caused by asphyxia and correlated with the 96-h neurological outcome and survival. Characteristics of earlier post-resuscitation EEG differed between cardiac and respiratory causes. Quantitative measures of EEG not only predicted neurological outcome and survival, but also have the potential to stratify CA with different causes.

Heart rate dynamics before spontaneous onset of ventricular fibrillation in patients with healed myocardial infarcts

NASA Technical Reports Server (NTRS)

Makikallio, T. H.; Koistinen, J.; Jordaens, L.; Tulppo, M. P.; Wood, N.; Golosarsky, B.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

1999-01-01

The traditional methods of analyzing heart rate (HR) variability have failed to predict imminent ventricular fibrillation (VF). We sought to determine whether new methods of analyzing RR interval variability based on nonlinear dynamics and fractal analysis may help to detect subtle abnormalities in RR interval behavior before the onset of life-threatening arrhythmias. RR interval dynamics were analyzed from 24-hour Holter recordings of 15 patients who experienced VF during electrocardiographic recording. Thirty patients without spontaneous or inducible arrhythmia events served as a control group in this retrospective case control study. Conventional time- and frequency-domain measurements, the short-term fractal scaling exponent (alpha) obtained by detrended fluctuation analysis, and the slope (beta) of the power-law regression line (log power - log frequency, 10(-4)-10(-2) Hz) of RR interval dynamics were determined. The short-term correlation exponent alpha of RR intervals (0.64 +/- 0.19 vs 1.05 +/- 0.12; p <0.001) and the power-law slope beta (-1.63 +/- 0.28 vs -1.31 +/- 0.20, p <0.001) were lower in the patients before the onset of VF than in the control patients, but the SD and the low-frequency spectral components of RR intervals did not differ between the groups. The short-term scaling exponent performed better than any other measurement of HR variability in differentiating between the patients with VF and controls. Altered fractal correlation properties of HR behavior precede the spontaneous onset of VF. Dynamic analysis methods of analyzing RR intervals may help to identify abnormalities in HR behavior before VF.

Loeffler endocarditis: silent right ventricular myocardium!

PubMed

Çetin, Süha; Heper, Gülümser; Gökhan Vural, Mustafa; Hazirolan, Tuncay

2016-07-01

We present the case of a 54-year-old male patient with Loeffler endocarditis. It is a rare disorder characterized by fibrous thickening of the endocardium leading to apical obliteration and restrictive cardiomyopathy resulting in heart failure, thromboembolic events or atrial fibrillation. To the best of our knowledge, this is the first case reporting the electrical silence of the right ventricular (RV) apex caused by fibrothrombotic thickening of this area. Under these circumstances RV apical implantation of an implantable cardioverter defibrillator (ICD) or pacemaker electrode may lead to unsuccessful stimulation of these devices.

An increasing electromechanical window is a predictive marker of ventricular fibrillation in anesthetized rabbit with ischemic heart.

PubMed

Limprasutr, Vudhiporn; Pirintr, Prapawadee; Kijtawornrat, Anusak; Hamlin, Robert L

2018-05-10

The QTc interval is widely used in Safety Pharmacological studies to predict arrhythmia risk, and the electromechanical window (EMW) and short-term variability of QT intervals (STV QT ) have been studied as new biomarkers for drug-induced Torsades de Pointes (TdP). However, the use of EMW and STV QT to predict ventricular fibrillation (VF) has not been elucidated. This study aimed to evaluate EMW and STV QT to predict VF in anesthetized rabbit model of VF. VF was induced by ligation of the left anterior descending and a descending branch of the left circumflex coronary arteries in a sample population of rabbits (n=18). VF was developed 55.6% (10/18). In rabbit with VF, the EMW was significantly higher than in rabbits without VF (96.3 ± 15.6 ms and 49.5 ± 5.6 ms, respectively, P<0.05). STV QT had significantly increased before the onset of VF in rabbits that experienced VF, but not in rabbits that did not experience VF (11.7 ± 1.8 ms and 3.7 ± 0.4 ms, respectively, P<0.05). The EMW and STV QT had better predictive power for VF with higher sensitivity and specificity than the QTc measure. The result suggested that the increasing of EMW, as well as the elevation of STV QT , can potentially be used as biomarkers for predicting of VF.

Defibrillation and resuscitation in a piglet model of pediatric ventricular fibrillation following AHA 2005 guidelines.

PubMed

Zhou, Zhengyu; Wang, Yubin; Zhou, Huiying; Huang, Meng; Liu, Huiting; Hsieh, Chengtai; Xue, Zhimou

2010-08-01

To evaluate the efficacy and safety of defibrillation on children according to AHA 2005 recommendations Pig resembles human in the chest configuration, anatomy and physiology of the cardiovascular and pulmonary systems. Piglets weighing 7.0 Kg ± 1.4kg, 14.0kg ± 2.8kg, 25.0kg ± 5.0kg respectively, which represented children 1 to 8 yr old were induced ventricular fibrillation (VF). An adult biphasic AED was used in conjunction with pediatric attenuating electrodes which could deliver 50-J shock for 2 min and two min of cardiopulmonary resuscitation (CPR) immediately followed it. If VF did not reverse, 70-J shock combined with CPR was used, and the protocol was repeated five times. If an organized cardiac rhythm with mean aortic pressure more than 60 mmHg persisted for an interval of 5 minutes, the animal was regarded as successfully resuscitated. If the AED recognized a "non-shockable" rhythm, CPR was also performed immediately for 2 min. The same resuscitation program was exercised on piglets of manual defibrillator group. Neurologic alertness score, hemodynamic and myocardial functions were evaluated, autopsy was routinely performed to document possible injuries. In the AED group, 14 out of 15 animals, were successfully resuscitated, among them 11 piglets were resuscitated by 50-J defibrillation combined with cardiopulmonary resuscitation, and other three recovered to normal by 1 or 2 times of 70-J shocks and CPR. All animals in manual defibrillator group were successfully resuscitated by 50-J shocks and CPR. Left ventricular ejection fraction and fractional area change were reduced significantly during 3-4 hr post-resuscitation (P<0.05) and returned to baseline ranges at the end of 72 hr. There was no evidence of myocardial and pulmonary damage during autopsy, and neurologic recovery was also normal. Data of blood gas analysis, blood electrolytes and myocardial enzymes does not show any statistically significant difference (P> 0.05) in the groups. 50 J biphasic

Minimal Invasive Left Ventricular Lead Repositioning is Safe and Effective in Distal Left Ventricular Lead Positions.

PubMed

Osztheimer, István; Szilágyi, Szabolcs; Pongor, Zsuzsanna; Zima, Endre; Molnár, Levente; Tahin, Tamás; Merkely, Béla; Gellér, László

2017-05-01

Treatment of left ventricular electrode dislocation and phrenic nerve stimulation remains an issue in the era of new electrode designs. Safety and efficacy of minimal invasive lead repositioning and pocket opening reposition procedures were evaluated between December 2005 and December 2012 at our center. Minimal invasive method was developed and widely utilized at our center to treat phrenic nerve stimulation. The distally positioned left ventricular lead is looped around by a deflectable catheter in the right atrium introduced from the femoral vein access and then pulled back. Coronary stent implantation was used afterwards for lead stabilization in some patients. 42 minimal invasive and 48 electrode repositions with pacemaker pocket opening were performed at 77 patients for left ventricular lead problems. Minimal invasive reposition could be carried out successfully in 69% of (29 patients) cases. Note that in 14.3% of the cases (six patients) minimal invasive procedures were acutely unsuccessful and crossover was necessary. In 16.6% of the cases (seven patients) lead issues were noted later during follow-up. Opening of the pocket could be carried out successfully in 81.2% (39 patients) and was unsuccessful acutely in 6.25% (three patients). Repeated dislocation was noticed, 12.5%, in this group (six patients). Complication during minimal invasive procedures was electrode injury in one case. Pocket openings were associated with several complications: atrial fibrillation, pericardial effusion, fever, hematoma, and right ventricular electrode dislodgement. Minimal invasive procedure-as the first line approach-is safe and feasible for left ventricular electrode repositioning in selected cases. © 2017 Wiley Periodicals, Inc.

Brain tissue water content in patients with idiopathic normal pressure hydrocephalus.

PubMed

Aygok, G; Marmarou, A; Fatouros, P; Young, H

2006-01-01

Relatively little is known regarding the water content of brain tissue in idiopathic normal-pressure hydrocephalus (NPH) patients. The objective of our study was to determine absolute water content non-invasively in hydrocephalic patients, particularly in the anterior and posterior ventricular horns and in the periventricular white matter. Ten patients who were diagnosed and treated for idiopathic NPH in our clinic were selected for study. Magnetic resonance imaging (MRI) techniques were used to obtain anatomical image slices for quantitative brain water measurements. Apparent diffusion coefficient measures were also extracted from regions of interest. To our knowledge, this is the first study to confirm that periventricular lucency seen on MRI represents increased water content in the extracellular space that is markedly elevated prior to shunting.

Late Presentation of Recurrent Monomorphic Ventricular Tachycardia following Minimally Invasive Mitral Valve Repair due to Epicardial Injury.

PubMed

South, Harry L; Osoro, Moses; Overly, Tjuan

2014-01-01

We report a 73-year-old male with late onset monomorphic ventricular tachycardia following mitral valve repair (MVR). Typically, injury to epicardial arteries following mitral valve repair/replacement presents immediately as ventricular tachycardia/fibrillation, difficulty weaning from cardiopulmonary bypass, worsening ECG changes, increasing cardiac biomarkers, or new wall motion abnormalities. Our case illustrates a "late complication" of a distorted circumflex artery following mitral valve repair and the importance of early diagnostic angiography and percutaneous intervention.

Atrial fibrillation and isolated systolic hypertension: the systolic hypertension in the elderly program and systolic hypertension in the elderly program-extension study.

PubMed

Vagaonescu, Tudor D; Wilson, Alan C; Kostis, John B

2008-06-01

We performed a post hoc analysis of the Systolic Hypertension in the Elderly Program database to assess the incidence of atrial fibrillation in the elderly hypertensive population, its influence on cardiovascular events, and whether antihypertensive treatment can prevent its onset. The Systolic Hypertension in the Elderly Program was a double-blind placebo-controlled trial in 4736 subjects with isolated systolic hypertension aged >or=60 years. Atrial fibrillation was an exclusion criterion from the trial. Participants were randomly assigned to stepped care treatment with chlorthalidone and atenolol (n=2365) or placebo (n=2371). The occurrence of atrial fibrillation and cardiovascular events over 4.7 years as well as the determination of cause of death at 4.7 and 14.3 years were followed. Ninety-eight subjects (2.06%) developed atrial fibrillation over 4.7 years mean follow-up, without significant difference between treated and placebo groups. Atrial fibrillation increased the risk for: total cardiovascular events (RR 1.69; 95% CI 1.21 to 2.36), rapid death (RR 3.29; 95% CI 1.08 to 10.00), total (RR 5.10; 95% CI 3.12 to 8.37) and nonfatal left ventricular failure (RR 5.31; 95% CI 3.09 to 9.13). All-cause and total cardiovascular death were significantly increased in the atrial fibrillation group at 4.7 years (HR 3.44; 95% CI 2.18 to 5.42; HR 2.39; 95% CI 1.05 to 5.43) and 14.3 years follow-up (HR 2.33; 95% CI 1.83 to 2.98; HR 2.21; 95% CI 1.54 to 3.17). Atrial fibrillation increased the risk for total cardiovascular events, rapid death, and left ventricular failure. All-cause mortality and total cardiovascular mortality were significantly increased in hypertensives with atrial fibrillation at 4.7 and 14.3 years follow-up.

Reduction of myocardial blood flow reserve in idiopathic dilated cardiomyopathy without overt heart failure and its relation with functional indices: an echo-Doppler and positron emission tomography study.

PubMed

Morales, Maria-Aurora; Neglia, Danilo; L'Abbate, Antonio

2008-08-01

Myocardial blood flow during pharmacological vasodilatation is depressed in patients with idiopathic dilated cardiomyopathy even the in absence of overt heart failure; the extent of myocardial blood flow abnormalities is not predictable by left ventricular ejection fraction (LVEF) and diastolic dimensions. To assess whether myocardial blood flow impairment in idiopathic dilated cardiomyopathy without overt heart failure can be related to Doppler-derived dP/dt and to echocardiographically determined left ventricular end systolic stress - which is linked to myocardial blood flow reserve in advanced disease. Twenty-six patients, New York Heart Association Class I-II, (LVEF 37.4 +/- 1.4%, left ventricular diastolic dimensions 62.6 +/- 0.9 mm) underwent resting/dipyridamole [13N]NH3 flow positron emission tomography and an ultrasonic study. Regional myocardial blood flow values (ml/min per g) were computed from positron emission tomography data in 13 left ventricular (LV) myocardial regions and averaged to provide mean myocardial blood flow and myocardial blood flow reserve, defined as dipyridamole/resting mean myocardial blood flow ratio. Resting myocardial blood flow was 0.686 +/- 0.045, dipyridamole myocardial blood flow 1.39 +/- 0.15 and myocardial blood flow reserve 2.12 +/- 0.2, lower than in controls (P < 0.01). The ratio dP/dt was directly related to dipyridamole myocardial blood flow and myocardial blood flow reserve (r = 0.552 and 0.703, P < 0.005 and P < 0.0001); no relation was found between myocardial blood flow and LVEF left ventricular diastolic dimensions, and left ventricular end systolic stress. In idiopathic dilated cardiomyopathy patients without overt heart failure, the extent of myocardial blood flow reserve impairment is related to dP/dt but not to more classical indices of left ventricular function.

F-amplitude, left atrial appendage velocity, and thromboembolic risk in nonrheumatic atrial fibrillation. Stroke Prevention in Atrial Fibrillation Investigators.

PubMed

Blackshear, J L; Safford, R E; Pearce, L A

1996-04-01

Reduced left atrial appendage velocity (LAAV) has been identified as a marker for thromboembolism in patients with atrial fibrillation. It was postulated that electrocardiographic (ECG) F-wave amplitude would correlate with LAAV, and inversely with the risk of thromboembolism in patients with atrial fibrillation. In all, 53 patients with nonrheumatic (NRAF) and 7 patients with rheumatic (RAF) atrial fibrillation underwent assessment of maximum LAAV, which was correlated to the maximum ECG F-wave voltage from lead V1 (F(max)). In 450 NRAF patients on neither aspirin nor warfarin, the relationship between F(max) and thromboembolic risk was assessed over an average follow-up of 1.3 years. F(max) did not correlate with LAAV (r = 0.2, p = 0.07). Patients with intermittent atrial fibrillation (n = 123) had smaller F(max) amplitude than patients with constant atrial fibrillation (n = 327) (mean 0.73 vs. 0.88 mV-1, p = 0.001). F(max) amplitude was not related to a history of hypertension, systolic blood pressure, duration of NRAF, abnormal transthoracic echocardiographic left ventricular (LV) systolic function or left atrial (LA) diameter. There was a strong trend for increased LV mass being related to smaller F(max) amplitude after adjusting for body surface area (p = 0.06). F(max) amplitude was not correlated with risk of embolic events, including only those events presumed by a panel of case-blinded neurologists to be cardioembolic. F(max) amplitude in NRAF is smaller in patients with intermittent versus constant AF. It does not correlate with LAAV, LA size, increased LV mass, or systolic dysfunction, hypertension, or risk of embolism. Therefore, F(max) amplitude may not be used as a surrogate for LAAV, or as a measure of thromboembolic risk in NRAF.

Brain Emboli After Left Ventricular Endocardial Ablation.

PubMed

Whitman, Isaac R; Gladstone, Rachel A; Badhwar, Nitish; Hsia, Henry H; Lee, Byron K; Josephson, S Andrew; Meisel, Karl M; Dillon, William P; Hess, Christopher P; Gerstenfeld, Edward P; Marcus, Gregory M

2017-02-28

Catheter ablation for ventricular tachycardia and premature ventricular complexes (PVCs) is common. Catheter ablation of atrial fibrillation is associated with a risk of cerebral emboli attributed to cardioversions and numerous ablation lesions in the low-flow left atrium, but cerebral embolic risk in ventricular ablation has not been evaluated. We enrolled 18 consecutive patients meeting study criteria scheduled for ventricular tachycardia or PVC ablation over a 9-month period. Patients undergoing left ventricular (LV) ablation were compared with a control group of those undergoing right ventricular ablation only. Patients were excluded if they had implantable cardioverter defibrillators or permanent pacemakers. Radiofrequency energy was used for ablation in all cases and heparin was administered with goal-activated clotting times of 300 to 400 seconds for all LV procedures. Pre- and postprocedural brain MRI was performed on each patient within a week of the ablation procedure. Embolic infarcts were defined as new foci of reduced diffusion and high signal intensity on fluid-attenuated inversion recovery brain MRI within a vascular distribution. The mean age was 58 years, half of the patients were men, half had a history of hypertension, and the majority had no known vascular disease or heart failure. LV ablation was performed in 12 patients (ventricular tachycardia, n=2; PVC, n=10) and right ventricular ablation was performed exclusively in 6 patients (ventricular tachycardia, n=1; PVC, n=5). Seven patients (58%) undergoing LV ablation experienced a total of 16 cerebral emboli, in comparison with zero patients undergoing right ventricular ablation ( P =0.04). Seven of 11 patients (63%) undergoing a retrograde approach to the LV developed at least 1 new brain lesion. More than half of patients undergoing routine LV ablation procedures (predominately PVC ablations) experienced new brain emboli after the procedure. Future research is critical to understanding the

Biatrial Electrical and Structural Atrial Changes in Heart Failure: Electroanatomic Mapping in Persistent Atrial Fibrillation in Humans.

PubMed

Prabhu, Sandeep; Voskoboinik, Aleksandr; McLellan, Alex J A; Peck, Kah Y; Pathik, Bhupesh; Nalliah, Chrishan J; Wong, Geoff R; Azzopardi, Sonia M; Lee, Geoffrey; Mariani, Justin; Ling, Liang-Han; Taylor, Andrew J; Kalman, Jonathan M; Kistler, Peter M

2018-01-01

This study sought to characterize the biatrial substrate in heart failure (HF) and persistent atrial fibrillation (PeAF). Atrial fibrillation (AF) and HF frequently coexist; however, the contribution of HF to the biatrial substrate in PeAF is unclear. Consecutive patients with PeAF and normal left ventricular (NLV) systolic function (left ventricular ejection fraction [LVEF] >55%) or idiopathic cardiomyopathy (LVEF ≤45%) undergoing AF ablation were enrolled. In AF, pulmonary vein (PV) cycle length (PVCL) was recorded via a multipolar catheter in each PV and in the left atrial appendage for 100 consecutive cycles. After electrical cardioversion, biatrial electroanatomic mapping was performed. Complex electrograms, voltage, scarring, and conduction velocity were assessed. Forty patients, 20 patients with HF (mean age: 62 ± 8.9 years; AF duration: 15 ± 11 months; LVEF: 33 ± 8.4%) and 20 with NLV (mean age: 59 ± 6.7 years; AF duration: 14 ± 9.1 months; p = 0.69; mean LVEF: 61 ± 3.6%; p < 0.001), were enrolled. HF reduced biatrial tissue voltage (p < 0.001) with greater voltage heterogeneity (p < 0.001). HF was associated with significantly more biatrial fractionation (left atrium [LA]: 30% vs. 9%; p < 0.001; right atrium [RA]: 28% vs. 11%; p < 0.001), low voltage (<0.5 mV) (LA: 23% vs. 6%; p = 0.002; RA: 20% vs 11%; p = 0.006), and scarring (<0.05 mV) in the LA (p = 0.005). HF was associated with a slower average PVCL (185 vs. 164 ms; p = 0.016), which correlated significantly with PV antral bipolar voltage (R = -0.62; p < 0.001) and fractionation (R = 0.46; p = 0.001). HF is associated with significantly reduced biatrial tissue voltage, fractionation, and prolongation of PVCL. Advanced biatrial remodeling may have implications for invasive and noninvasive rhythm control strategies in patients with AF and HF. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Ventricular fibrillation in acute myocardial infarction in Spanish patients: Results of the ARIAM database.

PubMed

Ruiz-Bailén, Manuel; Aguayo de Hoyos, Eduardo; Ruiz-Navarro, Silvia; Issa-Khozouz, Ziad; Reina-Toral, Antonio; Díaz-Castellanos, Miguel Angel; Rodríguez-García, Juan-José; Torres-Ruiz, Juan Miguel; Cárdenas-Cruz, Antonio; Camacho-Víctor, Angel

2003-08-01

The aim of this study has been to investigate the factors predisposing to primary or secondary ventricular fibrillation (VF) and the prognosis in Spanish patients with acute myocardial infarction (AMI) during their admission to the intensive care unit or the coronary care unit. A retrospective, observational study. The intensive care units and coronary care units of 119 Spanish hospitals. A retrospective cohort study including all the AMI patients listed in the ARIAM registry (Analysis of Delay in Acute Myocardial Infarction), a Spanish multicenter study. The study period was January 1995 to January 2001. Factors associated with the onset of VF were studied by univariate analysis. Multivariate analysis was used to evaluate the independent factors for the onset of VF and for mortality. A total of 17,761 patients with AMI were included in the study; 964 (5.4%) developed VF (primary in 735 patients, secondary in 229). In multivariate analysis, the variables that continued to show an association with the development of VF were the Killip and Kimball class, peak creatine kinase, APACHE II score, age, and time from the onset of symptoms to the initiation of thrombolysis. The mortality in the patients with any VF was 31.8% (27.8% in patients with primary VF and 49.1% in patients with secondary VF). The development of VF is an independent predictive factor for mortality in patients with AMI, with a crude odds ratio of 5.12 (95% confidence interval, 4.41-5.95) and an adjusted odds ratio of 2.73 (95% confidence interval, 2.12-3.51). Despite the considerable improvement in the treatment of AMI in recent years, the onset of either primary or secondary VF is associated with a poor prognosis. It is usually accompanied by extensive necrosis.

Right ventricular dyssynchrony in idiopathic pulmonary arterial hypertension: determinants and impact on pump function.

PubMed

Badagliacca, Roberto; Poscia, Roberto; Pezzuto, Beatrice; Papa, Silvia; Gambardella, Cristina; Francone, Marco; Mezzapesa, Mario; Nocioni, Martina; Nona, Alfred; Rosati, Riccardo; Sciomer, Susanna; Fedele, Francesco; Dario Vizza, Carmine

2015-03-01

Right ventricular (RV) dyssynchrony has been described in pulmonary arterial hypertension (PAH), but no evidence is available on its morphologic determinants and its effect on systolic function. The aim of this study was to evaluate the morphologic determinants of RV dyssynchrony by echocardiographic and cardiac magnetic resonance imaging and its effect on systolic function. In 60 consecutive idiopathic PAH (IPAH) patients with narrow QRS, RV dyssynchrony was evaluated by 2D speckle-tracking echocardiography, calculating the standard deviation of the times to peak systolic strain for the four mid-basal RV segments (RV-SD4). Patients were grouped by the median value of RV-SD4 (19 milliseconds) and compared for RV remodeling and systolic function parameters, WHO class, pulmonary hemodynamics and 6-minute walk test (6MWT). Despite similar pulmonary vascular resistance and mean pulmonary arterial pressure, patients with RV-SD4 at >19 milliseconds had advanced WHO class and worse 6MWT, RV hemodynamics, RV remodeling and systolic function parameters compared with patients at ≤19 milliseconds. The morphologic determinants of RV dyssynchrony resulted RV end-diastolic area, LV diastolic eccentricity index and RV mass volume ratio (r = 0.69, r(2) = 0.47, p < 0.0001). Finally, we found a significant inverse correlation between RV mid-basal segments post-systolic shortening time and cardiac index (r = -0.64, r(2) = 0.41, p = 0.001), accounting for the significant correlation between RV-SD4 and cardiac index (r = 0.57, r(2) = 0.32, p = 0.003). In IPAH with narrow QRS, RV dyssynchrony is associated with RV dilation and eccentric hypertrophy pattern, suggesting a role of segmental wall stress heterogeneity as the major determinant of mechanical delay. Post-systolic shortening, as inefficient contraction, contributes to pump dysfunction. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Cold aortic flush and chest compressions enable good neurologic outcome after 15 mins of ventricular fibrillation in cardiac arrest in pigs.

PubMed

Janata, Andreas; Weihs, Wolfgang; Schratter, Alexandra; Bayegan, Keywan; Holzer, Michael; Frossard, Martin; Sipos, Wolfgang; Springler, Gregor; Schmidt, Peter; Sterz, Fritz; Losert, Udo M; Laggner, Anton N; Kochanek, Patrick M; Behringer, Wilhelm

2010-08-01

The induction of deep cerebral hypothermia via ice-cold saline aortic flush during prolonged ventricular fibrillation cardiac arrest, followed by hypothermic stasis and delayed resuscitation (emergency preservation and resuscitation), improved neurologic outcome after cardiac arrest in pigs, as compared to conventional resuscitation. We hypothesized that emergency preservation and resuscitation with chest compressions would further improve outcome in the same model. Prospective experimental study. University research laboratory. : Twenty-four female, large, white breed pigs (27-37 kg). Fifteen minutes of ventricular fibrillation cardiac arrest were followed by 20 mins of resuscitation with chest compressions (control, n = 8), deep cerebral hypothermia via 200 mL/kg 4 degrees C saline aortic flush and hypothermic stasis (emergency preservation and resuscitation, n = 8), and emergency preservation and resuscitation combined with chest compressions (emergency preservation and resuscitation plus chest compressions, n = 8). At 35 mins after cardiac arrest, cardiopulmonary bypass was initiated, followed by defibrillation. Mild hypothermia was continued for 20 hrs. Pigs were evaluated after 9 days using a neurologic deficit (neurologic deficit score: 100% = brain dead; 0%-10% = normal) and an overall performance category score (overall performance category score: 1 = normal; 2 = slightly handicapped; 3 = severely handicapped; 4 = comatose; 5 = dead/brain dead). Brain temperature decreased from 38.5 degrees C to 15.3 degrees C +/- 3.3 degrees C in the emergency preservation and resuscitation group, and to 11.3 degrees C +/- 1.2 degrees C in the emergency preservation and resuscitation plus chest compressions group. In the control group, restoration of spontaneous circulation was achieved in four out of eight pigs, and one survived to 9 days. In the emergency preservation and resuscitation group, restoration of spontaneous circulation was achieved in seven out of eight pigs

Risk of ventricular arrhythmias associated with nonsedating antihistamine drugs

PubMed Central

José de Abajo, Francisco; Rodríguez, Luis Alberto García

1999-01-01

Aims To quantify and compare the incidence of ventricular arrhythmias associated with the use of five nonsedating antihistamines: acrivastine, astemizole, cetirizine, loratadine and terfenadine. The effects of age, sex, dose, duration of treatment, and the interaction with P450 inhibitor drugs were also examined. Methods We carried out a cohort study with a nested case-control analysis using the UK-based General Practice Research Database (GPRD). The study cohort included persons aged less than 80 years old who received their first prescription for any of the five study drugs between January 1, 1992 and September 30, 1996. We estimated relative risks and 95% confidence intervals of idiopathic ventricular arrhythmias with current use of antihistamines as compared with non use. Results The study cohort included 197 425 persons who received 513 012 prescriptions. Over the study period 18 valid cases of idiopathic ventricular arrhythmias were detected. Nine occurred during the current use of any antihistamine, resulting in a crude incidence of 1.9 per 10 000 person-years (95%CI: 1.0–3.6) and a relative risk of 4.2 (95%CI: 1.5–11.8) as compared with non use. Astemizole presented the highest relative risk (RR = 19.0; 95%CI: 4.8–76.0) of all study drugs, while terfenadine (RR = 2.1; 95%CI:0.5–8.5) was in the range of other nonsedating antihistamines. Older age was associated with a greater risk of ventricular arrhythmias (RR = 7.4; 95%CI: 2.6–21.4) and seemed to increase the effect of antihistamines (RR = 6.4; 95%CI: 1.7–24.8). The proportions of high dose terfenadine and the concomitant use with P450 inhibitors among current users of terfenadine were 2.7% and 3.4%, respectively over the study period with no single case of ventricular arrhythmias occurring in the presence of these two risk factors. Conclusions The use of nonsedating antihistamines increases the risk of ventricular arrhythmias by a factor of four in the general population. Yet, the absolute

Electromechanical vortex filaments during cardiac fibrillation

NASA Astrophysics Data System (ADS)

Christoph, J.; Chebbok, M.; Richter, C.; Schröder-Schetelig, J.; Bittihn, P.; Stein, S.; Uzelac, I.; Fenton, F. H.; Hasenfuß, G.; Gilmour, R. F., Jr.; Luther, S.

2018-03-01

The self-organized dynamics of vortex-like rotating waves, which are also known as scroll waves, are the basis of the formation of complex spatiotemporal patterns in many excitable chemical and biological systems. In the heart, filament-like phase singularities that are associated with three-dimensional scroll waves are considered to be the organizing centres of life-threatening cardiac arrhythmias. The mechanisms that underlie the onset, maintenance and control of electromechanical turbulence in the heart are inherently three-dimensional phenomena. However, it has not previously been possible to visualize the three-dimensional spatiotemporal dynamics of scroll waves inside cardiac tissues. Here we show that three-dimensional mechanical scroll waves and filament-like phase singularities can be observed deep inside the contracting heart wall using high-resolution four-dimensional ultrasound-based strain imaging. We found that mechanical phase singularities co-exist with electrical phase singularities during cardiac fibrillation. We investigated the dynamics of electrical and mechanical phase singularities by simultaneously measuring the membrane potential, intracellular calcium concentration and mechanical contractions of the heart. We show that cardiac fibrillation can be characterized using the three-dimensional spatiotemporal dynamics of mechanical phase singularities, which arise inside the fibrillating contracting ventricular wall. We demonstrate that electrical and mechanical phase singularities show complex interactions and we characterize their dynamics in terms of trajectories, topological charge and lifetime. We anticipate that our findings will provide novel perspectives for non-invasive diagnostic imaging and therapeutic applications.

Ventricular Fibrillation Waveform Changes during Controlled Coronary Perfusion Using Extracorporeal Circulation in a Swine Model.

PubMed

Gazmuri, Raúl J; Kaufman, Christopher L; Baetiong, Alvin; Radhakrishnan, Jeejabai

2016-01-01

Several characteristics of the ventricular fibrillation (VF) waveform have been found predictive of successful defibrillation and hypothesized to reflect the myocardial energy state. In an open-chest swine model of VF, we modeled "average CPR" using extracorporeal circulation (ECC) and assessed the time course of coronary blood flow, myocardial metabolism, and myocardial structure in relation to the amplitude spectral area (AMSA) of the VF waveform without artifacts related to chest compression. VF was induced and left untreated for 8 minutes in 16 swine. ECC was then started adjusting its flow to maintain a coronary perfusion pressure of 10 mmHg for 10 minutes. AMSA was calculated in the frequency domain and analyzed continuously with a 2.1 s timeframe and a Tukey window that moved ahead every 0.5 s. AMSA progressively declined during untreated VF. With ECC, AMSA increased from 7.0 ± 1.9 mV·Hz (at minute 8) to 12.8 ± 3.3 mV·Hz (at minute 14) (p < 0.05) without subsequent increase and showing a modest correlation with coronary blood flow of borderline statistical significance (r = 0.489, p = 0.0547). Myocardial energy measurements showed marked reduction in phosphocreatine and moderate reduction in ATP with increases in ADP, AMP, and adenosine along with myocardial lactate, all indicative of ischemia. Yet, ischemia did not resolve during ECC despite a coronary blood flow of ~ 30% of baseline. AMSA increased upon return of coronary blood flow during ECC. However, the maximal level was reached after ~ 6 minutes without further change. The significance of the findings for determining the optimal timing for delivering an electrical shock during resuscitation from VF remains to be further explored.

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

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

Statins as antiarrhythmics: a systematic review part I: effects on risk of atrial fibrillation.

PubMed

Abuissa, Hussam; O'Keefe, James H; Bybee, Kevin A

2009-10-01

Recent studies have demonstrated that statins may possess antiarrhythmic properties in addition to their lipid-lowering effects. Studies which reported the association of statins with the incidence of atrial arrhythmias were identified through a systematic review of published literature. One randomized, placebo-controlled trial of 200 patients undergoing cardiac surgery showed that atorvastatin decreased the incidence of postoperative atrial fibrillation by 61%. Observational studies in patients with stable coronary disease, left ventricular dysfunction, or those undergoing cardiac or noncardiac surgery show that statin therapy is associated with an approximately 50% lower rate of atrial fibrillation. Two small randomized trials reported conflicting results: one showing that atorvastatin reduced the recurrence of AF after electrical cardioversion and the other finding that pravastatin did not. Published data suggests that statins may possess antiarrhythmic properties that reduce the propensity for atrial fibrillation. Most of this data is observational; more randomized, placebo-controlled trials are needed.

Can sudden cardiac death in the young be predicted and prevented? Lessons from autopsy for the emergency physician.

PubMed

White, Jennifer L; Chang, Anna Marie; Cesar, Sergi; Sarquella-Brugada, Georgia

2018-06-01

Sudden unexpected death in the young, though rare, is devastating for both the family and the community. Although only 1.3 to 8.5 cases of sudden cardiac death (SCD) occur per 100 000 young people, autopsy is often inconclusive. Many causes of SCD are related to autosomal dominant inherited risk, however; therefore, answers are important for survivors. Causes of autopsy-positive SCD in young patients include hypertrophic cardiomyopathy and arrhythmogenic right ventricular dysplasia. Autopsy-negative SCD has been related to inherited arrhythmogenic causes such as long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, Wolff- Parkinson-White syndrome, and idiopathic ventricular fibrillation. The important question for the emergency physician is how SCD can be predicted and prevented in the young so that there is no need for an autopsy.

Use of New Imaging CARTO® Segmentation Module Software to Facilitate Ablation of Ventricular Arrhythmias.

PubMed

Tovia-Brodie, Oholi; Belhassen, Bernard; Glick, Aharon; Shmilovich, Haim; Aviram, Galit; Rosso, Raphael; Michowitz, Yoav

2017-02-01

A new imaging software (CARTO® Segmentation Module, Biosense Webster) allows preprocedural 3-D reconstruction of all heart chambers based on cardiac CT. We describe our initial experience with the new module during ablation of ventricular arrhythmias. Eighteen consecutive patients with idiopathic ventricular arrhythmias or ischemic ventricular tachycardia (VT) were studied. In the latter group, a combined endocardial and epicardial ablation was performed. Of the 14 patients with idiopathic arrhythmias, 12 were ablated in the outflow tract (OT), 1 in the midseptal left ventricle, and 1 at the left posterior fascicular area; acute successful ablation was achieved in 11 (78.6%) patients. The procedure was discontinued due to close proximity of the arrhythmia origin to the coronary arteries (CA) in 2 patients. Acute successful uncomplicated ablation was achieved in all 4 patients with ischemic VT. During ablation in the coronary cusps commissures, the CARTO® Segmentation Module accurately defined the cusps anatomy. The precise anatomic location provided by the module assisted in successfully ablating when information from activation mapping was not optimal, by ablating at the opposite side of the cusps. In addition, by demonstrating the precise location of the CA, it allowed safe ablation of arrhythmias that originated in close proximity to the CA both in the OT area and the epicardium, eliminating the need for repeat angiography. The CARTO® Segmentation Module is useful for accurate definition of the exact anatomic location of ventricular arrhythmias and for safely ablating them especially in close proximity to the CA. © 2016 Wiley Periodicals, Inc.

A Novel Antifibrotic Mechanism of Nintedanib and Pirfenidone. Inhibition of Collagen Fibril Assembly.

PubMed

Knüppel, Larissa; Ishikawa, Yoshihiro; Aichler, Michaela; Heinzelmann, Katharina; Hatz, Rudolf; Behr, Jürgen; Walch, Axel; Bächinger, Hans Peter; Eickelberg, Oliver; Staab-Weijnitz, Claudia A

2017-07-01

Idiopathic pulmonary fibrosis (IPF) is characterized by excessive deposition of extracellular matrix, in particular, collagens. Two IPF therapeutics, nintedanib and pirfenidone, decelerate lung function decline, but their underlying mechanisms of action are poorly understood. In this study, we sought to analyze their effects on collagen synthesis and maturation at important regulatory levels. Primary human fibroblasts from patients with IPF and healthy donors were treated with nintedanib (0.01-1.0 μM) or pirfenidone (100-1,000 μM) in the absence or presence of transforming growth factor-β1. Effects on collagen, fibronectin, FKBP10, and HSP47 expression, and collagen I and III secretion, were analyzed by quantitative polymerase chain reaction and Western blot. The appearance of collagen fibrils was monitored by scanning electron microscopy, and the kinetics of collagen fibril assembly was assessed using a light-scattering approach. In IPF fibroblasts, nintedanib reduced the expression of collagen I and V, fibronectin, and FKBP10 and attenuated the secretion of collagen I and III. Pirfenidone also down-regulated collagen V but otherwise showed fewer and less pronounced effects. By and large, the effects were similar in donor fibroblasts. For both drugs, electron microscopy of IPF fibroblast cultures revealed fewer and thinner collagen fibrils compared with untreated controls. Finally, both drugs dose-dependently delayed fibril formation of purified collagen I. In summary, both drugs act on important regulatory levels in collagen synthesis and processing. Nintedanib was more effective in down-regulating profibrotic gene expression and collagen secretion. Importantly, both drugs inhibited collagen I fibril formation and caused a reduction in and an altered appearance of collagen fibril bundles, representing a completely novel mechanism of action for both drugs.

Detection of Life Threatening Ventricular Arrhythmia Using Digital Taylor Fourier Transform.

PubMed

Tripathy, Rajesh K; Zamora-Mendez, Alejandro; de la O Serna, José A; Paternina, Mario R Arrieta; Arrieta, Juan G; Naik, Ganesh R

2018-01-01

Accurate detection and classification of life-threatening ventricular arrhythmia episodes such as ventricular fibrillation (VF) and rapid ventricular tachycardia (VT) from electrocardiogram (ECG) is a challenging problem for patient monitoring and defibrillation therapy. This paper introduces a novel method for detection and classification of life-threatening ventricular arrhythmia episodes. The ECG signal is decomposed into various oscillatory modes using digital Taylor-Fourier transform (DTFT). The magnitude feature and a novel phase feature namely the phase difference (PD) are evaluated from the mode Taylor-Fourier coefficients of ECG signal. The least square support vector machine (LS-SVM) classifier with linear and radial basis function (RBF) kernels is employed for detection and classification of VT vs. VF, non-shock vs. shock and VF vs. non-VF arrhythmia episodes. The accuracy, sensitivity, and specificity values obtained using the proposed method are 89.81, 86.38, and 93.97%, respectively for the classification of Non-VF and VF episodes. Comparison with the performance of the state-of-the-art features demonstrate the advantages of the proposition.

Detection of Life Threatening Ventricular Arrhythmia Using Digital Taylor Fourier Transform

PubMed Central

Tripathy, Rajesh K.; Zamora-Mendez, Alejandro; de la O Serna, José A.; Paternina, Mario R. Arrieta; Arrieta, Juan G.; Naik, Ganesh R.

2018-01-01

Accurate detection and classification of life-threatening ventricular arrhythmia episodes such as ventricular fibrillation (VF) and rapid ventricular tachycardia (VT) from electrocardiogram (ECG) is a challenging problem for patient monitoring and defibrillation therapy. This paper introduces a novel method for detection and classification of life-threatening ventricular arrhythmia episodes. The ECG signal is decomposed into various oscillatory modes using digital Taylor-Fourier transform (DTFT). The magnitude feature and a novel phase feature namely the phase difference (PD) are evaluated from the mode Taylor-Fourier coefficients of ECG signal. The least square support vector machine (LS-SVM) classifier with linear and radial basis function (RBF) kernels is employed for detection and classification of VT vs. VF, non-shock vs. shock and VF vs. non-VF arrhythmia episodes. The accuracy, sensitivity, and specificity values obtained using the proposed method are 89.81, 86.38, and 93.97%, respectively for the classification of Non-VF and VF episodes. Comparison with the performance of the state-of-the-art features demonstrate the advantages of the proposition.

Prospective Randomized Evaluation of Implantable Cardioverter-Defibrillator Programming in Patients With a Left Ventricular Assist Device.

PubMed

Richardson, Travis D; Hale, Leslie; Arteaga, Christopher; Xu, Meng; Keebler, Mary; Schlendorf, Kelly; Danter, Matthew; Shah, Ashish; Lindenfeld, JoAnn; Ellis, Christopher R

2018-02-23

Ventricular arrhythmias are common in patients with left ventricular assist devices (LVADs) but are often hemodynamically tolerated. Optimal implantable cardioverter defibrillator (ICD) tachy-programming strategies in patients with LVAD have not been determined. We sought to determine if an ultra-conservative ICD programming strategy in patients with LVAD affects ICD shocks. Adult patients with an existing ICD undergoing continuous flow LVAD implantation were randomized to standard ICD programming by their treating physician or an ultra-conservative ICD programming strategy utilizing maximal allowable intervals to detection in the ventricular fibrillation and ventricular tachycardia zones with use of ATP. Patients with cardiac resynchronization therapy (CRT) devices were also randomized to CRT ON or OFF. Patients were followed a minimum of 6 months. The primary outcome was time to first ICD shock. Among the 83 patients studied, we found no statistically significant difference in time to first ICD shock or total ICD shocks between groups. In the ultra-conservative group 16% of patients experienced at least one shock compared with 21% in the control group ( P =0.66). There was no difference in mortality, arrhythmic hospitalization, or hospitalization for heart failure. In the 41 patients with CRT ICDs fewer shocks were observed with CRT-ON but this was not statistically significant: 10% of patients with CRT-ON (n=21) versus 38% with CRT-OFF (n=20) received shocks ( P =0.08). An ultra-conservative programming strategy did not reduce ICD shocks. Programming restrictions on ventricular tachycardia and ventricular fibrillation zone therapy should be reconsidered for the LVAD population. The role of CRT in patients with LVAD warrants further investigation. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01977703. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Mechanism linking T-wave alternans to the genesis of cardiac fibrillation.

PubMed

Pastore, J M; Girouard, S D; Laurita, K R; Akar, F G; Rosenbaum, D S

1999-03-16

Although T-wave alternans has been closely associated with vulnerability to ventricular arrhythmias, the cellular processes underlying T-wave alternans and their role, if any, in the mechanism of reentry remain unclear. -T-wave alternans on the surface ECG was elicited in 8 Langendorff-perfused guinea pig hearts during fixed-rate pacing while action potentials were recorded simultaneously from 128 epicardial sites with voltage-sensitive dyes. Alternans of the repolarization phase of the action potential was observed above a critical threshold heart rate (HR) (209+/-46 bpm) that was significantly lower (by 57+/-36 bpm) than the HR threshold for alternation of action potential depolarization. The magnitude (range, 2.7 to 47.0 mV) and HR threshold (range, 171 to 272 bpm) of repolarization alternans varied substantially between cells across the epicardial surface. T-wave alternans on the surface ECG was explained primarily by beat-to-beat alternation in the time course of cellular repolarization. Above a critical HR, membrane repolarization alternated with the opposite phase between neighboring cells (ie, discordant alternans), creating large spatial gradients of repolarization. In the presence of discordant alternans, a small acceleration of pacing cycle length produced a characteristic sequence of events: (1) unidirectional block of an impulse propagating against steep gradients of repolarization, (2) reentrant propagation, and (3) the initiation of ventricular fibrillation. Repolarization alternans at the level of the single cell accounts for T-wave alternans on the surface ECG. Discordant alternans produces spatial gradients of repolarization of sufficient magnitude to cause unidirectional block and reentrant ventricular fibrillation. These data establish a mechanism linking T-wave alternans of the ECG to the pathogenesis of sudden cardiac death.

Members of the emergency medical team may have difficulty diagnosing rapid atrial fibrillation in Wolff-Parkinson-White syndrome.

PubMed

Koźluk, Edward; Timler, Dariusz; Zyśko, Dorota; Piątkowska, Agnieszka; Grzebieniak, Tomasz; Gajek, Jacek; Gałązkowski, Robert; Fedorowski, Artur

2015-01-01

Atrial fibrillation (AF) in patients with Wolff-Parkinson-White (WPW) syndrome is potentially life-threatening as it may deteriorate into ventricular fibrillation. The aim of this study was to assess whether the emergency medical team members are able to diagnose AF with a rapid ventricular response due to the presence of atrioventricular bypass tract in WPW syndrome. The study group consisted of 316 participants attending a national congress of emergency medicine. A total of 196 questionnaires regarding recognition and management of cardiac arrhythmias were distributed. The assessed part presented a clinical scenario with a young hemodynamically stable man who had a 12-lead electrocardiogram performed in the past with signs of pre-excitation, and who presented to the emergency team with an irregular broad QRS-complex tachycardia. A total of 71 questionnaires were filled in. Only one responder recognized AF due to WPW syndrome, while 5 other responders recognized WPW syndrome and paroxysmal supraventricular tachycardia or broad QRS-complex tachycardia. About 20% of participants did not select any diagnosis, pointing out a method of treatment only. The most common diagnosis found in the survey was ventricular tachycardia/broad QRS-complex tachycardia marked by approximately a half of the participants. Nearly 18% of participants recognized WPW syndrome, whereas AF was recognized by less than 10% of participants. Members of emergency medical teams have limited skills for recognizing WPW syndrome with rapid AF, and ventricular tachycardia is the most frequent incorrect diagnosis.

J Waves Are Associated With the Increased Occurrence of Life-Threatening Ventricular Tachyarrhythmia in Patients With Nonischemic Cardiomyopathy.

PubMed

Naruse, Yoshihisa; Nogami, Akihiko; Shinoda, Yasutoshi; Hanaki, Yuichi; Shirai, Yasuhiro; Kowase, Shinya; Kurosaki, Kenji; Machino, Takeshi; Kuroki, Kenji; Yamasaki, Hiro; Igarashi, Miyako; Sekiguchi, Yukio; Aonuma, Kazutaka

2016-12-01

Recent studies showed that J waves were associated with higher incidence of ventricular tachyarrhythmia (VT/VF) in patients with idiopathic ventricular fibrillation (VF) and myocardial infarction. We sought to assess the association between J waves and VT/VF in patients with nonischemic cardiomyopathy (NICM). We retrospectively enrolled 109 patients (79 men; mean age, 60 ± 15 years) with NICM who underwent implantable cardioverter defibrillator (ICD) implantation. The primary endpoint of this study was the occurrence of appropriate device therapy due to sustained VT/VF. The J wave was electrocardiographically defined as an elevation of the terminal portion of the QRS complex of >0.1 mV in at least 2 contiguous inferior or lateral leads. Among the 109 patients, 37 (34%) experienced an episode of appropriate device therapy during a median follow-up period of 25.9 (IQR 11.5-54.3) months. Kaplan-Meier curves showed that the presence of J waves on the 12-lead ECG obtained before device implantation was associated with an increased occurrence of appropriate device therapy (P < 0.001). Multivariate Cox proportional regression analysis revealed that the presence of J waves (HR 2.95; 95% CI 1.31-6.64; P = 0.009) was an independent predictor for the occurrence of appropriate device therapy. In the subgroup analysis of the patients with dilated or hypertrophic cardiomyopathy, J wave tended to increase the occurrence of appropriate device therapy (P = 0.056 and P = 0.092, respectively). The presence of J waves was an independent predictor for the occurrence of appropriate device therapy in patients with NICM who underwent ICD implantation. © 2016 Wiley Periodicals, Inc.

Achieving ventricular rate control using metoprolol in β-blocker-naive patients vs patients on chronic β-blocker therapy.

PubMed

Kuang, Patricia; Mah, Nathan D; Barton, Cassie A; Miura, Andrea J; Tanas, Laura R; Ran, Ran

2016-03-01

The objective of the study is to evaluate the difference in ventricular rate control using an intravenous (IV) metoprolol regimen commonly used in clinical practice in patients receiving chronic β-blocker therapy compared to patients considered β-blocker naive admitted to the emergency department (ED) for atrial fibrillation (AF) with rapid ventricular rate. A single-center retrospective cohort study of adult ED patients who were admitted with a rapid ventricular rate of 120 beats per minute (bpm) or greater and treated with IV metoprolol was performed. Rate control was defined as either a decrease in ventricular rate to less than 100 bpm or a 20% decrease in heart rate to less than 120 bpm after metoprolol administration. Patient demographics, differences in length of stay, and adverse events were recorded. A total of 398 patients were included in the study, with 79.4% (n=316) receiving chronic β-blocker therapy. Patients considered to be β-blocker naive were more likely to achieve successful rate control with IV metoprolol compared to patients on chronic β-blocker therapy (56.1% vs 42.4%; P=.03). β-Blocker-naive status was associated with a shorter length of stay in comparison to patients receiving chronic β-blocker therapy (1.79 vs 2.64 days; P<.01). Intravenous metoprolol for the treatment of atrial fibrillation with rapid ventricular rate was associated with a higher treatment response in patients considered β-blocker naive compared to patients receiving chronic β-blocker therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

Right ventricular pacemaker lead position is associated with differences in long-term outcomes and complications.

PubMed

Witt, Chance M; Lenz, Charles J; Shih, Henry H; Ebrille, Elisa; Rosenbaum, Andrew N; van Zyl, Martin; Aung, Htin; Manocha, Kevin K; Deshmukh, Abhishek J; Hodge, David O; Mulpuru, Siva K; Cha, Yong-Mei; Espinosa, Raul E; Asirvatham, Samuel J; Mcleod, Christopher J

2017-08-01

Cardiac pacing from the right ventricular apex is associated with detrimental long-term effects and nonapical pacing locations may be associated with improved outcomes. There is little data regarding complications with nonapical lead positions. The aim of this study was to assess long-term outcomes and lead-related complications associated with differing ventricular lead tip position. All adult patients who underwent dual-chamber pacemaker implantation from 2004 to 2014 were included if they had postprocedure chest radiographs amenable to lead position determination. Long-term outcomes and lead-related complication rates were recorded. These were compared at 5 years between: (1) apical and septal leads, (2) apical and nonseptal nonapical (NSNA), and (3) apical and septal with >40% ventricular pacing. We retrospectively evaluated 3,450 patients, which included 238 with a septal position and 733 with NSNA lead positions. Septal lead position was associated with a lower mortality compared to apical leads (24% vs. 31%, P = 0.02). In patients with greater than 40% pacing, septal leads were associated with significantly higher rates of incident atrial fibrillation compared to apical leads (49% vs. 34%, P = 0.04). NSNA positions were associated with a significantly higher rate of lead dislodgement (4% vs. 2%, P = 0.005) and need for revision (8% vs. 5%, P = 0.005). Septal pacemaker lead position is associated with a lower mortality compared to apically placed leads, but a higher incidence of atrial fibrillation with higher percentage ventricular pacing. NSNA lead locations are associated with more complications and should be avoided. © 2017 Wiley Periodicals, Inc.

Acute and chronic management in patients with Brugada syndrome associated with electrical storm of ventricular fibrillation.

PubMed

Ohgo, Takeshi; Okamura, Hideo; Noda, Takashi; Satomi, Kazuhiro; Suyama, Kazuhiro; Kurita, Takashi; Aihara, Naohiko; Kamakura, Shiro; Ohe, Tohru; Shimizu, Wataru

2007-06-01

Some patients with Brugada syndrome experience an electrical storm of ventricular fibrillation (VF). The purpose of this study was to investigate the clinical, laboratory, electrocardiographic, and electrophysiologic characteristics, acute and subsequent chronic treatment, and follow-up data of patients with Brugada syndrome associated with electrical storm of VF. Sixty-seven patients with Brugada syndrome (65 men and 2 women, age 46 +/- 14 years) were divided into three groups: 7 patients with a history of electrical storm of VF (group I), 39 symptomatic patients with documented VF and/or syncope (group II), and 21 asymptomatic patients (group III). Electrical storm was defined as three or more episodes of VF per day recorded by the memory of an implantable cardioverter-defibrillator. No significant differences were observed among the three groups with regard to clinical (age at diagnosis, familial history of sudden cardiac death), laboratory (SCN5A mutation and serum potassium level), electrocardiographic and electrophysiologic characteristics, and follow-up duration after diagnosis. However, arrhythmic events during follow-up after diagnosis and number of arrhythmic events per patient were significantly higher in group I compared with groups II and III. Isoproterenol infusion (0.003 +/- 0.003 microg/kg/min for 24 +/- 13 days) completely suppressed electrical storm of VF in all five patients treated and was successfully replaced with oral medications, including denopamine, quinidine, isoproterenol, cilostazol, and bepridil alone or in combination. No specifically clinical, laboratory, electrocardiographic, and electrophysiologic characteristics were recognized in patients with Brugada syndrome associated with electrical storm of VF. Isoproterenol infusion was effective as an acute treatment in suppressing electrical storm of VF and was successfully replaced with chronic oral medications.

Severe tricuspid regurgitation in the aged: atrial remodeling associated with long-standing atrial fibrillation.

PubMed

Yamasaki, Naohito; Kondo, Fumiaki; Kubo, Toru; Okawa, Makoto; Matsumura, Yoshihisa; Kitaoka, Hiroaki; Yabe, Toshikazu; Furuno, Takashi; Doi, Yoshinori

2006-12-01

Severe idiopathic tricuspid regurgitation (TR) occurs in the aged, but the mechanism of TR is unclear and there is little information on atrial abnormalities associated with this condition. This study retrospectively analyzed patients with severe functional TR presenting with common clinical features suggesting a distinct syndrome. Eleven patients with severe functional TR were identified by reviewing the records of 16,235 consecutive patients. All patients had undergone clinical evaluation including echocardiography, electrocardiography and laboratory data. The median age of patients with severe functional TR was 78 years. All had a long-standing history of atrial fibrillation (median duration, 23 years). Clinical features are characterized by severe functional TR due to annular dilation, markedly dilated right atrium, episodes of right-sided heart failure, absent or diminished fibrillation waves on electrocardiogram, bradycardia probably due to partial atrial standstill, and decreased atrial natriuretic peptide secretion. During long-term follow up, right atrial size progressively increased in association with worsening TR. Severe functional TR occurs with long-standing atrial fibrillation and causes right-sided heart failure. The TR is caused by tricuspid valve systolic coaptation loss due to tricuspid annular dilation associated with atrial dilation. This condition is associated with atrial abnormalities, such as atrial standstill and impaired atrial natriuretic peptide secretion. We propose that atrial remodeling associated with atrial fibrillation is central to the occurrence of the syndrome.

Early ventricular tachyarrhythmias after coronary artery bypass grafting surgery: Is it a real burden?

PubMed

Mouws, Elisabeth M J P; Yaksh, Ameeta; Knops, Paul; Kik, Charles; Boersma, Eric; Bogers, Ad J J C; de Groot, Natasja M S

2017-09-01

The prevalence of ventricular dysrhythmias (VD) [ventricular premature beats (VPBs), ventricular couplets (Vcouplets), ventricular runs (Vruns)] after coronary artery bypass grafting (CABG) has so far not been examined. The goal of this study is to examine characteristics of VD and whether they precede ventricular tachyarrhythmias (VTA) during a postoperative follow-up period of 5 days using continuous rhythm registrations. In addition, we determined predictive factors of VD/VTA. Incidences and burdens of VD/VTA were calculated in patients (N=105, 83 male, 65±9 years) undergoing primary, on-pump CABG. Independent risk factors were examined using multivariate analysis. VPBs, Vcouplets, and Vruns occurred in respectively 100%, 82.9%, and 48.6% with corresponding burdens of 0.05%, 0%, and 0%. Sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) did not occur in our cohort. Independent risk factors for VD included male gender, mitral valve insufficiency, hyperlipidemia, and age ≥60 years. VD are common in patients with coronary artery disease after CABG. Despite high incidences of these dysrhythmias, corresponding burdens are low and sustained VT or VF did not occur. Incidences were highest on the first postoperative day and diminished over time. Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Are left ventricular ejection fraction and left atrial diameter related to atrial fibrillation recurrence after catheter ablation?

PubMed Central

Jin, Xiao; Pan, Jianke; Wu, Huanlin; Xu, Danping

2018-01-01

Abstract Atrial fibrillation (AF), the most common form of arrhythmia, is associated with the prevalence of many common cardiovascular and cerebrovascular diseases. Catheter ablation is considered the first-line therapy for AF; however, AF recurrence is very common after catheter ablation. Studies have been performed to analyze the factors associated with AF recurrence, but none have reached a consistent conclusion on whether left ventricular ejection fraction (LVEF) and left atrial diameter (LA diameter) affect AF recurrence after catheter ablation. The databases PubMed, Embase, and the Cochrane Library were used to search for relevant studies up to September 2017. RevMan 5.3.5 software provided by the Cochrane Collaboration Network was used to conduct this meta-analysis. Thirteen studies involving 2825 patients were included in this meta-analysis. Overall, the results revealed that elevated LA diameter values were significantly associated with AF recurrence in patients after catheter ablation (MD = 2.19, 95% CI: 1.63–2.75, P < .001), while baseline LVEF levels were not significantly positively associated with AF recurrence in patients after catheter ablation (MD = −0.91, 95% CI: −1.18 to 1.67, P = .14). Overall, elevated LA diameter may be associated with AF recurrence after catheter ablation; however, there was no direct relationship between LVEF values and AF recurrence after catheter ablation when baseline LVEF values are normal or mildly decreased. Besides, because of publication bias, further studies should be performed to explore the mechanisms underlying AF recurrence. PMID:29768386

Cardiac fibrosis detected by magnetic resonance imaging on predicting time course diversity of left ventricular reverse remodeling in patients with idiopathic dilated cardiomyopathy.

PubMed

Ikeda, Yuki; Inomata, Takayuki; Fujita, Teppei; Iida, Yuichiro; Nabeta, Takeru; Ishii, Shunsuke; Maekawa, Emi; Yanagisawa, Tomoyoshi; Mizutani, Tomohiro; Naruke, Takashi; Koitabashi, Toshimi; Takeuchi, Ichiro; Ako, Junya

2016-11-01

This study aimed to identify the association between the time course of left ventricular reverse remodeling (LVRR) and late gadolinium enhancement in cardiac magnetic resonance imaging (LGE-cMRI) in patients with idiopathic dilated cardiomyopathy (IDCM). We identified 214 IDCM patients treated by optimal pharmacotherapies. LVRR was defined as ≥10 % increment in LV ejection fraction along with ≥10 % reduction in LV end-diastolic dimension. Findings of LGE-cMRI focusing on presence and extent of LGE were evaluated at baseline. Echocardiographic evaluation for detecting LVRR was performed in all patients for 3 years. The primary endpoint was defined as composite events (CEs) including readmission for heart failure, detection of major ventricular arrhythmia, and all-cause mortality. LVRR was found at <1 year in 59 patients (28 %, early responder), ≥1 year in 56 patients (26 %, late responder), and was absent in 99 patients (46 %, non-responder). Multivariate Cox-proportional hazards analysis revealed that both early responders (P = 0.02) and late responders (P < 0.001) had lower incidence of CEs than non-responders. Among 66 subjects (23 %) with complete cMRI evaluation, LGE was detected more often in late and non- than early responders (65, 83 vs. 23 % P < 0.001, respectively), whereas the LGE area was smaller in both early and late than non-responders (2 ± 3, 4 ± 3 vs. 12 ± 10 %, P < 0.001, respectively). In conclusion, evaluating the presence and the extent of LGE is useful for predicting the clinical differences of LVRR time course and subsequent long-term outcomes.

Left ventricular stiffness estimated by diastolic wall strain is associated with paroxysmal atrial fibrillation in structurally normal hearts.

PubMed

Uetake, Shunsuke; Maruyama, Mitsunori; Yamamoto, Teppei; Kato, Katsuhito; Miyauchi, Yasushi; Seino, Yoshihiko; Shimizu, Wataru

2016-12-01

Left ventricular (LV) diastolic dysfunction depends on an impaired relaxation and stiffness. Abnormal LV relaxation contributes to the development of atrial fibrillation (AF), but the role of LV stiffness in AF remains unclear. Diastolic wall strain (DWS), a load-independent, noninvasive direct measure of LV stiffness, correlates with prevalent AF. This study included 328 consecutive subjects with structurally normal hearts: 164 paroxysmal AF patients and 164 age- and sex-matched (1:1) controls. We calculated the DWS from the M-mode echocardiographic measurements of the LV posterior wall thickness at end-systole and end-diastole during sinus rhythm. The DWS was lower in the AF patients (0.35 ± 0.07) than in the controls (0.41 ± 0.06; P < 0.001). After adjusting for the risk factors of AF using a conditional logistic regression analysis, a history of hypertension, plasma brain-type natriuretic peptide level, and DWS were independently associated with AF prevalence, whereas body mass index, LV mass index, left atrial volume, and any conventional indices of the diastolic function were not. A low DWS (<0.380) was the strongest indicator of AF (odds ratio: 6.22, 95% confidence interval: 3.08-14.2, P < 0.001). Increased LV stiffness estimated by DWS was a strong determinant of the prevalence of AF. LV stiffness may play a role in the pathogenesis of paroxysmal AF in structurally normal hearts. © 2016 Wiley Periodicals, Inc.

Impact of Atrial Fibrillation Ablation on Left Ventricular Filling Pressure and Left Atrial Remodeling

PubMed Central

dos Santos, Simone Nascimento; Henz, Benhur Davi; Zanatta, André Rodrigues; Barreto, José Roberto; Loureiro, Kelly Bianca; Novakoski, Clarissa; dos Santos, Marcus Vinícius Nascimento; Giuseppin, Fabio F.; Oliveira, Edna Maria; Leite, Luiz Roberto

2014-01-01

Background Left ventricular (LV) diastolic dysfunction is associated with new-onset atrial fibrillation (AF), and the estimation of elevated LV filling pressures by E/e' ratio is related to worse outcomes in patients with AF. However, it is unknown if restoring sinus rhythm reverses this process. Objective To evaluate the impact of AF ablation on estimated LV filling pressure. Methods A total of 141 patients underwent radiofrequency (RF) ablation to treat drug-refractory AF. Transthoracic echocardiography was performed 30 days before and 12 months after ablation. LV functional parameters, left atrial volume index (LAVind), and transmitral pulsed and mitral annulus tissue Doppler (e' and E/e') were assessed. Paroxysmal AF was present in 18 patients, persistent AF was present in 102 patients, and long-standing persistent AF in 21 patients. Follow-up included electrocardiographic examination and 24-h Holter monitoring at 3, 6, and 12 months after ablation. Results One hundred seventeen patients (82.9%) were free of AF during the follow-up (average, 18 ± 5 months). LAVind reduced in the successful group (30.2 mL/m2 ± 10.6 mL/m2 to 22.6 mL/m2 ± 1.1 mL/m2, p < 0.001) compared to the non-successful group (37.7 mL/m2 ± 14.3 mL/m2 to 37.5 mL/m2 ± 14.5 mL/m2, p = ns). Improvement of LV filling pressure assessed by a reduction in the E/e' ratio was observed only after successful ablation (11.5 ± 4.5 vs. 7.1 ± 3.7, p < 0.001) but not in patients with recurrent AF (12.7 ± 4.4 vs. 12 ± 3.3, p = ns). The success rate was lower in the long-standing persistent AF patient group (57% vs. 87%, p = 0.001). Conclusion Successful AF ablation is associated with LA reverse remodeling and an improvement in LV filling pressure. PMID:25590928

Comprehensive Mutation Scanning of LMNA in 268 Patients With Lone Atrial Fibrillation

PubMed Central

Brauch, Katharine M.; Chen, Lin Y.; Olson, Timothy M.

2009-01-01

Atrial fibrillation (AF) is a heritable, genetically heterogeneous disorder. To identify gene defects that cause or confer susceptibility to AF, a cohort of 268 unrelated patients with idiopathic forms of familial and sporadic AF was recruited. LMNA, encoding the nuclear membrane proteins, lamin A/C, was selected as a candidate gene for lone AF based on its established association with a syndrome of dilated cardiomyopathy, conduction system disease, and AF. Comprehensive mutation scanning identified only 1 potentially pathogenic mutation. In conclusion, LMNA mutations rarely cause lone AF and routine genetic testing of LMNA in these patients does not appear warranted. PMID:19427440

Influence of coffee and caffeine consumption on atrial fibrillation in hypertensive patients.

PubMed

Mattioli, A V; Farinetti, A; Miloro, C; Pedrazzi, P; Mattioli, G

2011-06-01

Coffee and caffeine are widely consumed in Western countries. Little information is available on the influence of coffee and caffeine consumption on atrial fibrillation (AF) in hypertensive patients. We sought to investigate the relationship between coffee consumption and atrial fibrillation with regard to spontaneous conversion of arrhythmia. A group of 600 patients presenting with a first known episode of AF was investigated, and we identified 247 hypertensive patients. The prevalence of nutritional parameters was assessed with a food frequency questionnaire. Coffee and caffeine intake were specifically estimated. Left ventricular hypertrophy was evaluated by electrocardiogram (ECG) and echocardiogram. Coffee consumption was higher in normotensive patients. High coffee consumers were more frequent in normotensive patients compared with hypertensive patients. On the other hand, the intake of caffeine was similar in hypertensive and normotensive patients, owing to a higher intake in hypertensive patients from sources other than coffee. Within normotensive patients, we report that non-habitual and low coffee consumers showed the highest probability of spontaneous conversion (OR 1.93 95%CI 0.88-3.23; p=0.001), whereas, within hypertensive patients, moderate but not high coffee consumers had the lowest probability of spontaneous conversion (OR 1.13 95%CI 0.67-1.99; p=0.05). Coffee and caffeine consumption influence spontaneous conversion of atrial fibrillation. Normotensive non-habitual coffee consumers are more likely to convert arrhythmia within 48h from the onset of symptoms. Hypertensive patients showed a U-shaped relationship between coffee consumption and spontaneous conversion of AF, moderate coffee consumers were less likely to show spontaneous conversion of arrhythmia. Patients with left ventricular hypertrophy showed a reduced rate of spontaneous conversion of arrhythmia. Copyright © 2009 Elsevier B.V. All rights reserved.

Effect of irbesartan on development of atrial fibrosis and atrial fibrillation in a canine atrial tachycardia model with left ventricular dysfunction, association with p53.

PubMed

Kataoka, Naoya; Nishida, Kunihiro; Kinoshita, Koshi; Sakamoto, Tamotsu; Nakatani, Yosuke; Tsujino, Yasushi; Mizumaki, Koichi; Inoue, Hiroshi; Kinugawa, Koichiro

2016-12-01

Effects of an angiotensin II receptor blocker, irbesartan (IRB), on the development of atrial fibrosis and atrial fibrillation (AF) were assessed in a canine model of atrial tachycardia remodeling (ATR) with left ventricular dysfunction, together with its possible association with involvement of p53. Atrial tachypacing (400 bpm for 4 weeks) was used to induce ATR in beagles treated with placebo (ATR-dogs, n = 6) or irbesartan (IRB-dogs, n = 5). Non-paced sham dogs served as control (Control-dogs, n = 4). ATR- and IRB-dogs developed tachycardia-induced left ventricular dysfunction. Atrial effective refractory period (AERP) shortened (83 ± 5 ms, p < 0.05), inter-atrial conduction time prolonged (72 ± 2 ms, p < 0.05), and AF duration increased (29 ± 5 s, p < 0.05 vs. baseline) after 4 weeks in ATR-dogs. ATR-dogs also had a larger area of atrial fibrous tissue (5.2 ± 0.5 %, p < 0.05 vs. Control). All these changes, except for AERP, were attenuated in IRB-dogs (92 ± 3 ms, 56 ± 3 ms, 9 ± 5 s, and 2.5 ± 0.7 %, respectively; p < 0.05 vs. ATR for each). In ATR-dogs, p53 expression in the left atrium decreased by 42 % compared with Control-dogs (p < 0.05); however, it was highly expressed in IRB-dogs (+89 % vs. ATR). Transforming growth factor (TGF)-β1 expression was enhanced in ATR-dogs (p < 0.05 vs. Control) but reduced in IRB-dogs (p < 0.05 vs. ATR). Irbesartan suppresses atrial fibrosis and AF development in a canine ATR model with left ventricular dysfunction in association with p53.

Right versus left atrial pacing in patients with sick sinus syndrome and paroxysmal atrial fibrillation (Riverleft study): study protocol for randomized controlled trial.

PubMed

Ramdjan, Tanwier T T K; van der Does, Lisette J M E; Knops, Paul; Res, Jan C J; de Groot, Natasja M S

2014-11-17

The incidence of sick sinus syndrome will increase due to population ageing. Consequently, this will result in an increase in the number of pacemaker implantations. The atrial lead is usually implanted in the right atrial appendage, but this position may be ineffective for prevention of atrial fibrillation. It has been suggested that pacing distally in the coronary sinus might be more successful in preventing atrial fibrillation episodes. The aim of this trial is to study the efficacy of distal coronary sinus versus right atrial appendage pacing in preventing atrial fibrillation episodes in patients with sick sinus syndrome. This study is designed as a multicenter, randomized controlled trial. Patients with sick sinus syndrome and at least one atrial fibrillation episode of 30 seconds or more in the six months before recruitment will be eligible for participation in this study.All participants will be randomized between pacing distally in the coronary sinus and right atrial appendage. Randomization is stratified for all participating centers. Conventional dual-chamber pacemakers with advanced home monitoring functionality will be implanted. The ventricular lead will be implanted in the right ventricular apex. The first three months of the 36-month follow-up period are considered as run-in time. During the pre-randomization visit and follow-up, an interview, electrocardiogram and pacemaker assessment will be performed, prescribed antiarrhythmic medication will be reviewed and patients will be asked to complete an SF-36 questionnaire. An echocardiographic examination will be conducted in the pre-randomization phase and at the end of each follow-up year. Home monitoring will be used to send daily reports in case of atrial fibrillation episodes. This randomized controlled trial is the first in which home monitoring will be used to compare atrial fibrillation recurrences between pacing in the distal coronary sinus or right atrial appendage. Home monitoring gives the

Atrioventricular node functional remodeling induced by atrial fibrillation.

PubMed

Zhang, Youhua; Mazgalev, Todor N

2012-09-01

The atrioventricular node (AVN) plays a vital role in determining the ventricular rate during atrial fibrillation (AF). AF results in profound electrophysiological and structural remodeling in the atria as well as the sinus node. However, it is unknown whether AVN undergoes remodeling during AF. To determine whether AVN undergoes functional remodeling during AF. AVN conduction properties were studied in vitro in 9 rabbits with AF and 10 normal controls. A previously validated index of AVN dual-pathway electrophysiology, His-electrogram alternans, was used to monitor fast-pathway or slow-pathway (SP) AVN conduction in these experiments. AVN conduction properties were further studied in vivo in 7 dogs with chronic AF and 8 controls. Compared with the control rabbits, the rabbits with AF had a longer AVN conduction time (83 ± 16 ms vs 68 ± 7 ms; P <.01), longer AVN effective refractory period (141 ± 27 ms vs 100 ± 9 ms; P <.01), an earlier transition from fast-pathway to SP conduction (at a longer prematurity, 249 ± 60 ms vs 171 ± 24 ms; P <.01), and a slower ventricular rate during simulated AF (RR interval 249 ± 42 ms vs 202 ± 12 ms; P <.01). Notably, a larger proportion of conducted beats utilized the SP in AF preparations (92% ± 12% vs 63% ± 32%; P <.05). Long-term AF in dogs resulted in a longer atrioventricular conduction time and AVN effective refractory period and a slower ventricular rate during AF compared with the controls. Pronounced AVN functional electrophysiological remodeling occurs after long-term AF, which could lead to a spontaneous slowing of the ventricular rate. Furthermore, the SP dominance during AF underscores the effectiveness of its modification by ablation for ventricular rate control during AF. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

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

Circulating microRNAs in arrhythmogenic right ventricular cardiomyopathy with ventricular arrhythmia.

PubMed

Yamada, Shinya; Hsiao, Ya-Wen; Chang, Shih-Lin; Lin, Yenn-Jiang; Lo, Li-Wei; Chung, Fa-Po; Chiang, Shuo-Ju; Hu, Yu-Feng; Tuan, Ta-Chuan; Chao, Tze-Fan; Liao, Jo-Nan; Lin, Chin-Yu; Chang, Yao-Ting; Te, Abigail Louise D; Tsai, Yung-Nan; Chen, Shih-Ann

2018-06-01

MicroRNAs (miRNAs) have been implicated in cardiac diseases. This study aimed to characterize the circulating miRNAs in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and correlate the miRNAs with the clinical outcomes of ARVC. This study included 62 patients with ventricular arrhythmia (VA): 28 patients (45%) had definite ARVC, 11 (18%) had borderline or possible ARVC, and 23 (37%) had idiopathic ventricular tachycardia (VT). In addition, 33 age- and sex-matched healthy subjects were enrolled as normal control subjects. The expression of selected miRNAs was analysed in all study subjects. The clinical outcomes of patients with definite ARVC after catheter ablation were further investigated. On the basis of the miRNA polymerase chain reaction array, we selected 11 miRNAs for analysis of their expression in the plasma of all subjects. Definite ARVC patients had significantly higher expression of circulating miR-144-3p, 145-5p, 185-5p, and 494 than the three other groups. Out of 25 definite ARVC patients who underwent radiofrequency catheter ablation, recurrent VA occurred in 8 patients (32%) during the follow-up period (45 ± 20 months). Definite ARVC patients with recurrent VA had a higher level of circulating miR-494 than did those without recurrence. Receiver operating characteristic analysis showed miR-494 to be a predictive factor of recurrent VA (area under the curve: 0.832). Plasma levels of miR-144-3p, 145-5p, 185-5p, and 494 were significantly elevated in definite ARVC patients with VA. An increased plasma level of miR-494 was associated with the recurrence of VA after ablation in definite ARVC patients.

Idiopathic ophthalmodynia and idiopathic rhinalgia: two topographic facial pain syndromes.

PubMed

Pareja, Juan A; Cuadrado, María L; Porta-Etessam, Jesús; Fernández-de-las-Peñas, César; Gili, Pablo; Caminero, Ana B; Cebrián, José L

2010-09-01

To describe 2 topographic facial pain conditions with the pain clearly localized in the eye (idiopathic ophthalmodynia) or in the nose (idiopathic rhinalgia), and to propose their distinction from persistent idiopathic facial pain. Persistent idiopathic facial pain, burning mouth syndrome, atypical odontalgia, and facial arthromyalgia are idiopathic facial pain syndromes that have been separated according to topographical criteria. Still, some other facial pain syndromes might have been veiled under the broad term of persistent idiopathic facial pain. Through a 10-year period we have studied all patients referred to our neurological clinic because of facial pain of unknown etiology that might deviate from all well-characterized facial pain syndromes. In a group of patients we have identified 2 consistent clinical pictures with pain precisely located either in the eye (n=11) or in the nose (n=7). Clinical features resembled those of other localized idiopathic facial syndromes, the key differences relying on the topographic distribution of the pain. Both idiopathic ophthalmodynia and idiopathic rhinalgia seem specific pain syndromes with a distinctive location, and may deserve a nosologic status just as other focal pain syndromes of the face. Whether all such focal syndromes are topographic variants of persistent idiopathic facial pain or independent disorders remains a controversial issue.

Survival After Ventricular Fibrillation Cardiac Arrest in the Sao Paulo Metropolitan Subway System: First Successful Targeted Automated External Defibrillator (AED) Program in Latin America.

PubMed

Gianotto-Oliveira, Renan; Gonzalez, Maria Margarita; Vianna, Caio Brito; Monteiro Alves, Maurício; Timerman, Sergio; Kalil Filho, Roberto; Kern, Karl B

2015-10-09

Targeted automated external defibrillator (AED) programs have improved survival rates among patients who have an out-of-hospital cardiac arrest (OHCA) in US airports, as well as European and Japanese railways. The Sao Paulo (Brazil) Metro subway carries 4.5 million people per day. A targeted AED program was begun in the Sao Paulo Metro with the objective to improve survival from cardiac arrest. A prospective, longitudinal, observational study of all cardiac arrests in the Sao Paulo Metro was performed from September 2006 through November 2012. This study focused on cardiac arrest by ventricular arrhythmias, and the primary endpoint was survival to hospital discharge with minimal neurological impairment. A total of 62 patients had an initial cardiac rhythm of ventricular fibrillation. Because no data on cardiac arrest treatment or outcomes existed before beginning this project, the first 16 months of the implementation was used as the initial experience and compared with the subsequent 5 years of full operation. Return of spontaneous circulation was not different between the initial 16 months and the subsequent 5 years (6 of 8 [75%] vs. 39 of 54 [72%]; P=0.88). However, survival to discharge was significantly different once the full program was instituted (0 of 8 vs. 23 of 54 [43%]; P=0.001). Implementation of a targeted AED program in the Sao Paulo Metro subway system saved lives. A short interval between arrest and defibrillation was key for good long-term, neurologically intact survival. These results support strategic expansion of targeted AED programs in other large Latin American cities. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Ventricular fibrillation cardiac arrest produces a chronic striatal hyperdopaminergic state that is worsened by methylphenidate treatment.

PubMed

Nora, Gerald J; Harun, Rashed; Fine, David F; Hutchison, Daniel; Grobart, Adam C; Stezoski, Jason P; Munoz, Miranda J; Kochanek, Patrick M; Leak, Rehana K; Drabek, Tomas; Wagner, Amy K

2017-07-01

Cardiac arrest survival rates have improved with modern resuscitation techniques, but many survivors experience impairments associated with hypoxic-ischemic brain injury (HIBI). Currently, little is understood about chronic changes in striatal dopamine (DA) systems after HIBI. Given the common empiric clinical use of DA enhancing agents in neurorehabilitation, investigation evaluating dopaminergic alterations after cardiac arrest (CA) is necessary to optimize rehabilitation approaches. We hypothesized that striatal DA neurotransmission would be altered chronically after ventricular fibrillation cardiac arrest (VF-CA). Fast-scan cyclic voltammetry was used with median forebrain bundle (MFB) maximal electrical stimulations (60Hz, 10s) in rats to characterize presynaptic components of DA neurotransmission in the dorsal striatum (D-Str) and nucleus accumbens 14 days after a 5-min VF-CA when compared to Sham or Naïve. VF-CA increased D-Str-evoked overflow [DA], total [DA] released, and initial DA release rate versus controls, despite also increasing maximal velocity of DA reuptake (V max ). Methylphenidate (10 mg/kg), a DA transporter inhibitor, was administered to VF-CA and Shams after establishing a baseline, pre-drug 60 Hz, 5 s stimulation response. Methylphenidate increased initial evoked overflow [DA] more-so in VF-CA versus Sham and reduced D-Str V max in VF-CA but not Shams; these findings are consistent with upregulated striatal DA transporter in VF-CA versus Sham. Our work demonstrates that 5-min VF-CA increases electrically stimulated DA release with concomitant upregulation of DA reuptake 2 weeks after brief VF-CA insult. Future work should elucidate how CA insult duration, time after insult, and insult type influence striatal DA neurotransmission and related cognitive and motor functions. © 2017 International Society for Neurochemistry.

Changes of end-tidal carbon dioxide during cardiopulmonary resuscitation from ventricular fibrillation versus asphyxial cardiac arrest

PubMed Central

Lin, Qing-ming; Fang, Xiang-shao; Zhou, Li-li; Fu, Yue; Zhu, Jun; Huang, Zi-tong

2014-01-01

BACKGROUND: Partial pressure of end-tidal carbon dioxide (PETCO2) has been used to monitor the effectiveness of precordial compression (PC) and regarded as a prognostic value of outcomes in cardiopulmonary resuscitation (CPR). This study was to investigate changes of PETCO2 during CPR in rats with ventricular fibrillation (VF) versus asphyxial cardiac arrest. METHODS: Sixty-two male Sprague-Dawley (SD) rats were randomly divided into an asphyxial group (n=32) and a VF group (n=30). PETCO2 was measured during CPR from a 6-minute period of VF or asphyxial cardiac arrest. RESULTS: The initial values of PETCO2 immediately after PC in the VF group were significantly lower than those in the asphyxial group (12.8±4.87 mmHg vs. 49.2±8.13 mmHg, P=0.000). In the VF group, the values of PETCO2 after 6 minutes of PC were significantly higher in rats with return of spontaneous circulation (ROSC), compared with those in rats without ROSC (16.5±3.07 mmHg vs. 13.2±2.62 mmHg, P=0.004). In the asphyxial group, the values of PETCO2 after 2 minutes of PC in rats with ROSC were significantly higher than those in rats without ROSC (20.8±3.24 mmHg vs. 13.9±1.50 mmHg, P=0.000). Receiver operator characteristic (ROC) curves of PETCO2 showed significant sensitivity and specificity for predicting ROSC in VF versus asphyxial cardiac arrest. CONCLUSIONS: The initial values of PETCO2 immediately after CPR may be helpful in differentiating the causes of cardiac arrest. Changes of PETCO2 during CPR can predict outcomes of CPR. PMID:25215160

Reduction in unnecessary ventricular pacing fails to affect hard clinical outcomes in patients with preserved left ventricular function: a meta-analysis.

PubMed

Shurrab, Mohammed; Healey, Jeff S; Haj-Yahia, Saleem; Kaoutskaia, Anna; Boriani, Giuseppe; Carrizo, Aldo; Botto, Gianluca; Newman, David; Padeletti, Luigi; Connolly, Stuart J; Crystal, Eugene

2017-02-01

Several pacing modalities across multiple manufacturers have been introduced to minimize unnecessary right ventricular pacing. We conducted a meta-analysis to assess whether ventricular pacing reduction modalities (VPRM) influence hard clinical outcomes in comparison to standard dual-chamber pacing (DDD). An electronic search was performed using Cochrane Central Register, PubMed, Embase, and Scopus. Only randomized controlled trials (RCT) were included in this analysis. Outcomes of interest included: frequency of ventricular pacing (VP), incident persistent/permanent atrial fibrillation (PerAF), all-cause hospitalization and all-cause mortality. Odds ratios (OR) were reported for dichotomous variables. Seven RCTs involving 4119 adult patients were identified. Ventricular pacing reduction modalities were employed in 2069 patients: (MVP, Medtronic Inc.) in 1423 and (SafeR, Sorin CRM, Clamart) in 646 patients. Baseline demographics and clinical characteristics were similar between VPRM and DDD groups. The mean follow-up period was 2.5 ± 0.9 years. Ventricular pacing reduction modalities showed uniform reduction in VP in comparison to DDD groups among all individual studies. The incidence of PerAF was similar between both groups {8 vs. 10%, OR 0.84 [95% confidence interval (CI) 0.57; 1.24], P = 0.38}. Ventricular pacing reduction modalities showed no significant differences in comparison to DDD for all-cause hospitalization or all-cause mortality [9 vs. 11%, OR 0.82 (95% CI 0.65; 1.03), P= 0.09; 6 vs. 6%, OR 0.97 (95% CI 0.74; 1.28), P = 0.84, respectively]. Novel VPRM measures effectively reduce VP in comparison to standard DDD. When actively programmed, VPRM did not improve clinical outcomes and were not superior to standard DDD programming in reducing incidence of PerAF, all-cause hospitalization, or all-cause mortality.

Association of pulse pressure with new-onset atrial fibrillation in patients with hypertension and left ventricular hypertrophy: the Losartan Intervention For Endpoint (LIFE) reduction in hypertension study.

PubMed

Larstorp, Anne Cecilie K; Ariansen, Inger; Gjesdal, Knut; Olsen, Michael H; Ibsen, Hans; Devereux, Richard B; Okin, Peter M; Dahlöf, Björn; Kjeldsen, Sverre E; Wachtell, Kristian

2012-08-01

Previous studies have found pulse pressure (PP), a marker of arterial stiffness, to be an independent predictor of atrial fibrillation (AF) in general and hypertensive populations. We examined whether PP predicted new-onset AF in comparison with other blood pressure components in the Losartan Intervention For Endpoint reduction in hypertension study, a double-blind, randomized (losartan versus atenolol), parallel-group study, including 9193 patients with hypertension and electrocardiographic left ventricular hypertrophy. In 8810 patients with neither a history of AF nor AF at baseline, Minnesota coding of electrocardiograms confirmed new-onset AF in 353 patients (4.0%) during mean 4.9 years of follow-up. In multivariate Cox regression analyses, baseline and in-treatment PP and baseline and in-treatment systolic blood pressure predicted new-onset AF, independent of baseline age, height, weight, and Framingham Risk Score; sex, race, and treatment allocation; and in-treatment heart rate and Cornell product. PP was the strongest single blood pressure predictor of new-onset AF determined by the decrease in the -2 Log likelihood statistic, in comparison with systolic blood pressure, diastolic blood pressure, and mean arterial pressure. When evaluated in the same model, the predictive effect of systolic and diastolic blood pressures together was similar to that of PP. In this population of patients with hypertension and left ventricular hypertrophy, PP was the strongest single blood pressure predictor of new-onset AF, independent of other risk factors.

Impact of the right ventricular lead position on clinical outcome and on the incidence of ventricular tachyarrhythmias in patients with CRT-D.

PubMed

Kutyifa, Valentina; Bloch Thomsen, Poul Erik; Huang, David T; Rosero, Spencer; Tompkins, Christine; Jons, Christian; McNitt, Scott; Polonsky, Bronislava; Shah, Amil; Merkely, Bela; Solomon, Scott D; Moss, Arthur J; Zareba, Wojciech; Klein, Helmut U

2013-12-01

Data on the impact of right ventricular (RV) lead location on clinical outcome and ventricular tachyarrhythmias in cardiac resynchronization therapy with defibrillator (CRT-D) patients are limited. To evaluate the impact of different RV lead locations on clinical outcome in CRT-D patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy trial. We investigated 742 of 1089 CRT-D patients (68%) with adjudicated RV lead location enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy trial to evaluate the impact of RV lead location on cardiac events. The primary end point was heart failure or death; secondary end points included ventricular tachycardia (VT), ventricular fibrillation (VF), or death and VT or VF alone. Eighty-six patients had the RV lead positioned at the RV septal or right ventricular outflow tract region, combined as nonapical RV group, and 656 patients had apical RV lead location. There was no difference in the primary end point in patients with nonapical RV lead location versus those with apical RV lead location (hazard ratio [HR] 0.98; 95% confidence interval [CI] 0.54-1.80; P = .983). Echocardiographic response to CRT-D was comparable across RV lead location groups (P > .05 for left ventricular end-diastolic volume, left ventricular end-systolic volume, and left atrial volume percent change). However, nonapical RV lead location was associated with significantly higher risk of VT/VF/death (HR 2.45; 95% CI 1.36-4.41; P = .003) and VT/VF alone (HR 2.52; 95% CI 1.36-4.65; P = .002), predominantly in the first year after device implantation. Results were consistent in patients with left bundle branch block. In CRT-D patients, there is no benefit of nonapical RV lead location in clinical outcome or echocardiographic response. Moreover, nonapical RV lead location is associated with an increased risk of ventricular tachyarrhythmias, particularly in the

Contemporary clinical trials in ventricular tachycardia and fibrillation: implications of ESVEM, CASCADE, and CASH for clinical management.

PubMed

Anderson, J L

1995-10-01

Recent clinical trials in patients with ventricular tachycardia (VT) or fibrillation (VF) have occurred in the setting of the disappointing results of postinfarction secondary prevention studies using Class I antiarrhythmics (e.g., CAST). ESVEM addressed in a randomized trial whether electrophysiologic study (EPS) or Holter monitoring (HM) is a more accurate predictor of long-term antiarrhythmic drug efficacy in VT/VF patients (N=486) and what the relative efficacy of various antiarrhythmic agents is for VT/VF. Surprisingly, arrhythmia recurrence rates were not significantly different by the method of determining an efficacy prediction. However, arrhythmia recurrence and mortality were lower (by about 50% at 1 year) in patients treated with sotalol (a mixed Class II/III agent) than with other drugs (Class I). CASCADE evaluated empiric amiodarone versus guided (EPS or HM) standard (Class I) therapy in survivors of out-of-hospital cardiac arrest due to VF. The primary endpoint of cardiac death, resuscitated VF, or syncopal shock (in ICD patients) was reduced by amiodarone compared with conventional therapy (9% vs 23% at 1 year). An interim report of the ongoing CASH study suggested in 230 survivors of cardiac arrest that propafenone (Class IC) provided less effective prophylaxis (approximately 20% 1-year mortality) compared with randomly assigned therapies with amiodarone, metoprolol, or an ICD (approximately 14% mortality rates) and was excluded from further study. These studies have led to a paradigm shift in the approach to antiarrhythmic therapy of VT/VF: drugs with antisympathetic plus Class III (refractoriness prolonging) action (i.e., sotalol, amiodarone) are superior to traditional drugs with Class I( conduction slowing) effects, even when guided by EPS or HM.

An Effective and Reproducible Model of Ventricular Fibrillation in Crossbred Yorkshire Swine (Sus scrofa) for Use in Physiologic Research.

PubMed

Burgert, James M; Johnson, Arthur D; Garcia-Blanco, Jose C; Craig, W John; O'Sullivan, Joseph C

2015-10-01

Transcutaneous electrical induction (TCEI) has been used to induce ventricular fibrillation (VF) in laboratory swine for physiologic and resuscitation research. Many studies do not describe the method of TCEI in detail, thus making replication by future investigators difficult. Here we describe a detailed method of electrically inducing VF that was used successfully in a prospective, experimental resuscitation study. Specifically, an electrical current was passed through the heart to induce VF in crossbred Yorkshire swine (n = 30); the current was generated by using two 22-gauge spinal needles, with one placed above and one below the heart, and three 9V batteries connected in series. VF developed in 28 of the 30 pigs (93%) within 10 s of beginning the procedure. In the remaining 2 swine, VF was induced successfully after medial redirection of the superior parasternal needle. The TCEI method is simple, reproducible, and cost-effective. TCEI may be especially valuable to researchers with limited access to funding, sophisticated equipment, or colleagues experienced in interventional cardiology techniques. The TCEI method might be most appropriate for pharmacologic studies requiring VF, VF resulting from the R-on-T phenomenon (as in prolonged QT syndrome), and VF arising from other ectopic or reentrant causes. However, the TCEI method does not accurately model the most common cause of VF, acute coronary occlusive disease. Researchers must consider the limitations of TCEI that may affect internal and external validity of collected data, when designing experiments using this model of VF.

Atrial Fibrillation: Diagnosis

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Histological evidence of inflammatory reaction associated with fibrosis in the atrial and ventricular walls in a case-control study of patients with history of atrial fibrillation.

PubMed

Mitrofanova, Lubov B; Orshanskaya, Victoria; Ho, Siew Yen; Platonov, Pyotr G

2016-12-01

Chronic inflammation in the atrial myocardium was shown to play an important role in the development of atrial fibrosis in patients with atrial fibrillation (AF). However, it is not clear to what extent atrial inflammatory reaction associated with AF extends on the ventricular myocardium. Our aim was to assess the extent of fibrosis and lymphomononuclear infiltration in human ventricular myocardium and explore its association with AF. Medical records from consecutive autopsies were checked for presence of AF. Heart specimens from 30 patients died from cardiovascular causes (64 ± 12 years, 17 men) were collected in three equal groups: no AF, paroxysmal AF, and permanent AF. Tissue samples were taken from the Bachmann's bundle, crista terminalis, posterior left atrium, left ventricle and right ventricle free walls and stained with Masson's trichrome for analysis of fibrosis extent. Immunohistochemistry was performed using antibodies against CD3- and CD45-antigens and quantified as number of antigen-positive cells per 1 mm 2 . Fibrosis extent, CD3+ and CD45+ cell counts were elevated in AF patients at all sites (P < 0.001 for all). Fibrosis extent demonstrated correlation with both CD3+ and CD45+ cell counts in the right (r = 0.781, P < 0.001 for CD45+ and r = 0.720, P < 0.001 for CD3+) and the left (r = 0.515, P = 0.004 for CD45+ and r = 0.573, P = 0.001 for CD3+) ventricles. Neither fibrosis nor inflammatory cell count showed association with either age or comorbidities. Histological signs of chronic inflammation affecting ventricular myocardium are strongly associated with AF and demonstrate significant correlation with fibrosis extent that cannot be explained by cardiovascular comorbidities otherwise. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.

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

Idiopathic subvalvular aortic aneurysm masquerading as acute coronary syndrome.

PubMed

Natarajan, Balaji; Ramanathan, Sundar; Subramaniam, Natarajan; Janardhanan, Rajesh

2016-09-02

Subvalvular aneurysms are the least common type of left ventricular (LV) aneurysms and can be fatal. Subaortic LV aneurysms are much rarer than submitral LV aneurysms and mostly reported in infancy. They can be congenital or acquired secondary to infections, cardiac surgery or trauma. Here, we report a unique presentation of a large, idiopathic subaortic aneurysm in an adult masquerading as an acute coronary syndrome. Diagnosis was made with the help of a CT aortography. Aneurysm was surgically resected with good results. This case highlights the clinical presentation and management of subaortic aneurysms, an important differential for congenital aortic malformations. 2016 BMJ Publishing Group Ltd.

Early Ventricular Tachycardia or Fibrillation in Patients With ST Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention and Impact on Mortality and Stent Thrombosis (from the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction Trial).

PubMed

Kosmidou, Ioanna; Embacher, Monica; McAndrew, Thomas; Dizon, José M; Mehran, Roxana; Ben-Yehuda, Ori; Mintz, Gary S; Stone, Gregg W

2017-11-15

The prevalence and impact of early ventricular arrhythmias (ventricular tachycardia [VT]/ventricular fibrillation [VF]) occurring before mechanical revascularization for acute ST segment elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention are poorly understood. We sought to investigate the association between early VT/VF and long-term clinical outcomes using data from the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction trial. Among 3,602 patients with STEMI, 108 patients (3.0%) had early VT/VF. Baseline clinical characteristics were similar in patients with versus without early VT/VF. Patients with early VT/VF had shorter symptom-to-balloon times and lower left ventricular ejection fraction and underwent more frequent thrombectomy compared with patients without early VT/VF. Adjusted 3-year rates of all-cause death (15.7% vs 6.5%; adjusted hazard ratio 2.62, 95% confidence interval 1.48 to 4.61, p <0.001) and stent thrombosis (13.7% vs 5.7%; adjusted hazard ratio 2.74, 95% confidence interval 1.52 to 4.93, p <0.001) were significantly higher in patients with early VT/VF compared with patients without early VT/VF. In conclusion, in the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction trial, VT/VF occurring before coronary angiography and revascularization in patients with STEMI was strongly associated with increased 3-year rates of death and stent thrombosis. Further investigation into the mechanisms underlying the increased risk of early stent thrombosis in patients with early VT/VF is required. Copyright © 2017 Elsevier Inc. All rights reserved.

Recurrent left ventricular myxoma presenting as cerebrovascular accidents in a teenage girl.

PubMed

Vermeulen, Tom; Conraads, Viviane M; Vrints, Christiaan; Rodrigus, Inez E

2009-12-01

Myxoma cordis is the most frequent primary cardiac tumour in adults. Paediatric primary cardiac tumours are rare, the most common type being rhabdomyoma. Atrial and ventricular myxomas occur infrequently in the paediatric age group. Intracardiac myxomas are seen with an estimated incidence of 0.5 per million population per year. Approximately 70% of the affected patients are of female gender. Recurrences are rare (1.3%). Asymptomatic recurrences are observed in young patients who have a familial history of tumour or multifocal myxomas. Although rare, cardiac aetiology (atrial fibrillation, intracardiac thrombi, patent foramen ovale, myxoma, endocarditis) should be considered. In children presenting with central neurological symptoms, a cardiac aetiology has to be considered. We describe a rare case of an 18-year-old girl presenting with a recurrent left ventricular myxoma, accompanied by neurological deficits.

Dronedarone in high-risk permanent atrial fibrillation.

PubMed

Connolly, Stuart J; Camm, A John; Halperin, Jonathan L; Joyner, Campbell; Alings, Marco; Amerena, John; Atar, Dan; Avezum, Álvaro; Blomström, Per; Borggrefe, Martin; Budaj, Andrzej; Chen, Shih-Ann; Ching, Chi Keong; Commerford, Patrick; Dans, Antonio; Davy, Jean-Marc; Delacrétaz, Etienne; Di Pasquale, Giuseppe; Diaz, Rafael; Dorian, Paul; Flaker, Greg; Golitsyn, Sergey; Gonzalez-Hermosillo, Antonio; Granger, Christopher B; Heidbüchel, Hein; Kautzner, Josef; Kim, June Soo; Lanas, Fernando; Lewis, Basil S; Merino, Jose L; Morillo, Carlos; Murin, Jan; Narasimhan, Calambur; Paolasso, Ernesto; Parkhomenko, Alexander; Peters, Nicholas S; Sim, Kui-Hian; Stiles, Martin K; Tanomsup, Supachai; Toivonen, Lauri; Tomcsányi, János; Torp-Pedersen, Christian; Tse, Hung-Fat; Vardas, Panos; Vinereanu, Dragos; Xavier, Denis; Zhu, Jun; Zhu, Jun-Ren; Baret-Cormel, Lydie; Weinling, Estelle; Staiger, Christoph; Yusuf, Salim; Chrolavicius, Susan; Afzal, Rizwan; Hohnloser, Stefan H

2011-12-15

Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in high-risk permanent atrial fibrillation. We assigned patients who were at least 65 years of age with at least a 6-month history of permanent atrial fibrillation and risk factors for major vascular events to receive dronedarone or placebo. The first coprimary outcome was stroke, myocardial infarction, systemic embolism, or death from cardiovascular causes. The second coprimary outcome was unplanned hospitalization for a cardiovascular cause or death. After the enrollment of 3236 patients, the study was stopped for safety reasons. The first coprimary outcome occurred in 43 patients receiving dronedarone and 19 receiving placebo (hazard ratio, 2.29; 95% confidence interval [CI], 1.34 to 3.94; P=0.002). There were 21 deaths from cardiovascular causes in the dronedarone group and 10 in the placebo group (hazard ratio, 2.11; 95% CI, 1.00 to 4.49; P=0.046), including death from arrhythmia in 13 patients and 4 patients, respectively (hazard ratio, 3.26; 95% CI, 1.06 to 10.00; P=0.03). Stroke occurred in 23 patients in the dronedarone group and 10 in the placebo group (hazard ratio, 2.32; 95% CI, 1.11 to 4.88; P=0.02). Hospitalization for heart failure occurred in 43 patients in the dronedarone group and 24 in the placebo group (hazard ratio, 1.81; 95% CI, 1.10 to 2.99; P=0.02). Dronedarone increased rates of heart failure, stroke, and death from cardiovascular causes in patients with permanent atrial fibrillation who were at risk for major vascular events. Our data show that this drug should not be used in such patients. (Funded by Sanofi-Aventis; PALLAS ClinicalTrials.gov number, NCT01151137.).

Left ventricle to aorta valved conduit for relief of diffuse left ventricular outflow tract obstruction.

PubMed

Reder, R F; Dimich, I; Steinfeld, L; Litwak, R S

1977-06-01

Operative relief of congenital tunnel subaortic stenosis by means of local incision or excision, or both, has generally been unsatisfactory. The use of a valve-bearing conduit between the left ventricular apex and thoracic aorta offers a predictable means of bypassing the left ventricular outflow obstruction. The procedure was used in a 17 year old girl with an excellent hemodynamic result. The history of operative management with diverting plantation of valved conduits in this position have not been defined, but use of these prostheses appears advisable in severe subvalvular, valvular and supravalvular obstructions that are not readily amenable to predictable and safe surgical palliation. The operation may prove useful in selected cases of idiopathic hypertrophic obstructive cardiomyopathy.

Assessing the Atrial Electromechanical Coupling during Atrial Focal Tachycardia, Flutter, and Fibrillation using Electromechanical Wave Imaging in Humans

PubMed Central

Provost, Jean; Costet, Alexandre; Wan, Elaine; Gambhir, Alok; Whang, William; Garan, Hasan; Konofagou, Elisa E.

2015-01-01

Minimally-invasive treatments of cardiac arrhythmias such as radio-frequency ablation are gradually gaining in importance in clinical practice but still lack a noninvasive imaging modality which provides insight into the source or focus of an arrhythmia. Cardiac deformations imaged at high temporal and spatial resolution can be used to elucidate the electrical activation sequence in normal and paced human subjects non-invasively and could potentially aid to better plan and monitor ablation-based arrhythmia treatments. In this study, a novel ultrasound-based method is presented that can be used to quantitatively characterize focal and reentrant arrhythmias. Spatio-temporal maps of the full-view of the atrial and ventricular mechanics were obtained in a single heartbeat, revealing with otherwise unobtainable detail the electromechanical patterns of atrial flutter, fibrillation, and tachycardia in humans. During focal arrhythmias such as premature ventricular complex and focal atrial tachycardia, the previously developed electromechanical wave imaging methodology is hereby shown capable of identifying the location of the focal zone and the subsequent propagation of cardiac activation. During reentrant arrhythmias such as atrial flutter and fibrillation, Fourier analysis of the strains revealed highly correlated mechanical and electrical cycle lengths and propagation patterns. High frame rate ultrasound imaging of the heart can be used non-invasively and in real time, to characterize the lesser-known mechanical aspects of atrial and ventricular arrhythmias, also potentially assisting treatment planning for intraoperative and longitudinal monitoring of arrhythmias. PMID:26361338

QT/RR relationship in patients after remote anterior myocardial infarction with left ventricular dysfunction and different types of ventricular arrhythmias.

PubMed

Szydlo, Krzysztof; Trusz-Gluza, Maria; Wita, Krystian; Filipecki, Artur; Orszulak, Witold; Urbanczyk, Dagmara; Krauze, Jolanta; Kolasa, Jaroslaw; Tabor, Zbigniew

2008-01-01

QT/RR relationship was found to be both rate-dependent and rate-independent, what suggests the influence of autonomic drive and other not-autonomic related factors on it. The steeper QT/RR slope in patients after acute myocardial infarction (MI) was described, but the relationship to ventricular arrhythmias is unknown. The purpose of this study was to calculate differences in QT/RR relationship in patients after remote anterior MI with left ventricular dysfunction and different types of ventricular arrhythmias. The cohort of 95 patients (age: 63 +/- 11 years, LVEF: 35 +/- 9%) with previous anterior MI (mean 1.1 years) was divided into two well-matched groups-50 patients without episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) (NoVT/VF: 39 males, 64 +/- 12 years, LVEF 37 +/- 8%) and 45 patients with VT and/or VF (all with ICD implanted) (VT/VF: 35 males, 62 +/- 10 years, LVEF 34 +/- 10%). No true antiarrhythmics were used. QT/RR slope was calculated from 24-hour Holter ECG for the entire recording (E), daytime (D) and nighttime (N) periods. Groups did not differ in basic clinical data (age, LVEF, treatment). QT/RR slopes were steeper in VT/VF than in NoVT/VF group in all analyzed periods: E - 0.195 +/- 0.03 versus 0.15 +/- 0.03 (P < 0.001), N - 0.190 +/- 0.03 versus 0.138 +/- 0.03 (P < 0.001) and D - 0.200 +/- 0.04 versus 0.152 +/- 0.03 (P < 0.001). No significant day-to-night differences were found in both groups. Steeper QT/RR slope and complete lack of day-to-night differences in VT/VF patients show inappropriate QT adaptation to the heart rate changes. The prognostic significance of this parameter needs prospective studies.

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

Efficacy of implantable cardioverter defibrillators in young patients with catecholaminergic polymorphic ventricular tachycardia: success depends on substrate.

PubMed

Miyake, Christina Y; Webster, Gregory; Czosek, Richard J; Kantoch, Michal J; Dubin, Anne M; Avasarala, Kishor; Atallah, Joseph

2013-06-01

The effectiveness of implantable cardioverter-defibrillator (ICD) therapy for the management of catecholaminergic polymorphic ventricular tachycardia (VT) in young patients is not known. ICD discharges are not always effective and inappropriate discharges are common, both resulting in morbidity and mortality. This is a multicenter, retrospective review of young patients with catecholaminergic polymorphic VT and ICDs from 5 centers. ICD discharges were evaluated to determine arrhythmia mechanism, appropriateness, efficacy of therapy, and complications. A total of 24 patients were included. Median (interquartile range) ages at onset of catecholaminergic polymorphic VT symptoms and ICD implant were 10.6 (5.0-13.8) years and 13.7 (10.7-16.3) years, respectively. Fourteen patients received 140 shocks. Ten patients (42%) experienced 75 appropriate shocks and 11 patients (46%) received 65 inappropriate shocks. On actuarial analysis, freedom from appropriate shock at 1 year after ICD implant was 75%. Of appropriate shocks, only 43 (57%) demonstrated successful primary termination. All successful appropriate ICD discharges were for ventricular fibrillation. No episodes of polymorphic VT or bidirectional VT demonstrated successful primary termination. The adjusted mean (95% confidence interval) cycle length of successful discharges was significantly shorter than unsuccessful discharges (168 [152-184] ms versus 245 [229-262] ms; adjusted P=0.002). Electrical storm occurred in 29% (4/14) and induction of more malignant ventricular arrhythmias in 36% (5/14). There were no deaths. ICD efficacy in catecholaminergic polymorphic VT depends on arrhythmia mechanism. Episodes of ventricular fibrillation were uniformly successfully treated, whereas polymorphic and bidirectional VT did not demonstrate successful primary termination. Inappropriate shocks, electrical storm, and ICD complications were common.

Transmural recording of shock potential gradient fields, early postshock activations, and refibrillation episodes associated with external defibrillation of long-duration ventricular fibrillation in swine.

PubMed

Allred, James D; Killingsworth, Cheryl R; Allison, J Scott; Dosdall, Derek J; Melnick, Sharon B; Smith, William M; Ideker, Raymond E; Walcott, Gregory P

2008-11-01

Knowledge of the shock potential gradient (nablaV) and postshock activation is limited to internal defibrillation of short-duration ventricular fibrillation (SDVF). The purpose of this study was to determine these variables after external defibrillation of long-duration VF (LDVF). In six pigs, 115-20 plunge needles with three to six electrodes each were inserted to record throughout both ventricles. After the chest was closed, the biphasic defibrillation threshold (DFT) was determined after 20 seconds of SDVF with external defibrillation pads. After 7 minutes of LDVF, defibrillation shocks that were less than or equal to the SDVF DFT strength were given. For DFT shocks (1632 +/- 429 V), the maximum minus minimum ventricular voltage (160 +/- 100 V) was 9.8% of the shock voltage. Maximum cardiac nablaV (28.7 +/- 17 V/cm) was 4.7 +/- 2.0 times the minimum nablaV (6.2 +/- 3.5 V/cm). Although LDVF did not increase the DFT in five of the six pigs, it significantly lengthened the time to earliest postshock activation following defibrillation (1.6 +/- 2.2 seconds for SDVF and 4.9 +/- 4.3 seconds for LDVF). After LDVF, 1.3 +/- 0.8 episodes of spontaneous refibrillation occurred per animal, but there was no refibrillation after SDVF. Compared with previous studies of internal defibrillation, during external defibrillation much less of the shock voltage appears across the heart and the shock field is much more even; however, the minimum nablaV is similar. Compared with external defibrillation of SDVF, the biphasic external DFT for LDVF is not increased; however, time to earliest postshock activation triples. Refibrillation is common after LDVF but not after SDVF in these normal hearts, indicating that LDVF by itself can cause refibrillation without requiring preexisting heart disease.

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�

Hands-On Defibrillation Skills of Pediatric Acute Care Providers During a Simulated Ventricular Fibrillation Cardiac Arrest Scenario

PubMed Central

Bhalala, Utpal S.; Balakumar, Niveditha; Zamora, Maria; Appachi, Elumalai

2018-01-01

Introduction: Timely defibrillation in ventricular fibrillation cardiac arrest (VFCA) is associated with good outcome. While defibrillation skills of pediatric providers have been reported to be poor, the factors related to poor hands-on defibrillation skills of pediatric providers are largely unknown. The aim of our study was to evaluate delay in individual steps of the defibrillation and human and non-human factors associated with poor hands-on defibrillation skills among pediatric acute care providers during a simulated VFCA scenario. Methods: We conducted a prospective observational study of video evaluation of hands-on defibrillation skills of pediatric providers in a simulated VFCA in our children's hospital. Each provider was asked to use pads followed by paddles to provide 2 J/kg shock to an infant mannequin in VFCA. The hands-on skills were evaluated for struggle with any step of defibrillation, defined a priori as >10 s delay with particular step. The data was analyzed using chi-square test with significant p-value < 0.05. Results: A total of 68 acute care providers were evaluated. Median time to first shock was 97 s (IQR: 60–122.5 s) and did not correlate with provider factors, except previous experience with the defibrillator used in study. The number of providers who struggled (>10 s delay) with each of connecting the pads/paddles to the device, using pads/paddles on the mannequin and using buttons on the machine was 34 (50%), 26 (38%), and 31 (46%), respectively. Conclusions: The defibrillation skills of providers in a tertiary care children's hospital are poor. Both human and machine-related factors are associated with delay in defibrillation. Prior use of the study defibrillator is associated with a significantly shorter time-to-first shock as compared to prior use of any other defibrillator or no prior use of any defibrillator. PMID:29740571

Modifying Ventricular Fibrillation by Targeted Rotor Substrate Ablation: Proof-of-Concept from Experimental Studies to Clinical VF

PubMed Central

KRUMMEN, DAVID E.; HAYASE, JUSTIN; VAMPOLA, STEPHEN P.; HO, GORDON; SCHRICKER, AMIR A.; LALANI, GAUTAM G.; BAYKANER, TINA; COE, TAYLOR M.; CLOPTON, PAUL; RAPPEL, WOUTER-JAN; OMENS, JEFFREY H.; NARAYAN, SANJIV M.

2016-01-01

Introduction Recent work has suggested a role for organized sources in sustaining ventricular fibrillation (VF). We assessed whether ablation of rotor substrate could modulate VF inducibility in canines, and used this proof-of-concept as a foundation to suppress antiarrhythmic drug-refractory clinical VF in a patient with structural heart disease. Methods and Results In 9 dogs, we introduced 64-electrode basket catheters into one or both ventricles, used rapid pacing at a recorded induction threshold to initiate VF, and then defibrillated after 18±8 seconds. Endocardial rotor sites were identified from basket recordings using phase mapping, and ablation was performed at nonrotor (sham) locations (7 ± 2 minutes) and then at rotor sites (8 ± 2 minutes, P = 0.10 vs. sham); the induction threshold was remeasured after each. Sham ablation did not alter canine VF induction threshold (preablation 150 ± 16 milliseconds, postablation 144 ± 16 milliseconds, P = 0.54). However, rotor site ablation rendered VF noninducible in 6/9 animals (P = 0.041), and increased VF induction threshold in the remaining 3. Clinical proof-of-concept was performed in a patient with repetitive ICD shocks due to VF refractory to antiarrhythmic drugs. Following biventricular basket insertion, VF was induced and then defibrillated. Mapping identified 4 rotors localized at borderzone tissue, and rotor site ablation (6.3 ± 1.5 minutes/site) rendered VF noninducible. The VF burden fell from 7 ICD shocks in 8 months preablation to zero ICD therapies at 1 year, without antiarrhythmic medications. Conclusions Targeted rotor substrate ablation suppressed VF in an experimental model and a patient with refractory VF. Further studies are warranted on the efficacy of VF source modulation. PMID:26179310

Hands-On Defibrillation Skills of Pediatric Acute Care Providers During a Simulated Ventricular Fibrillation Cardiac Arrest Scenario.

PubMed

Bhalala, Utpal S; Balakumar, Niveditha; Zamora, Maria; Appachi, Elumalai

2018-01-01

Introduction: Timely defibrillation in ventricular fibrillation cardiac arrest (VFCA) is associated with good outcome. While defibrillation skills of pediatric providers have been reported to be poor, the factors related to poor hands-on defibrillation skills of pediatric providers are largely unknown. The aim of our study was to evaluate delay in individual steps of the defibrillation and human and non-human factors associated with poor hands-on defibrillation skills among pediatric acute care providers during a simulated VFCA scenario. Methods: We conducted a prospective observational study of video evaluation of hands-on defibrillation skills of pediatric providers in a simulated VFCA in our children's hospital. Each provider was asked to use pads followed by paddles to provide 2 J/kg shock to an infant mannequin in VFCA. The hands-on skills were evaluated for struggle with any step of defibrillation, defined a priori as >10 s delay with particular step. The data was analyzed using chi-square test with significant p -value < 0.05. Results: A total of 68 acute care providers were evaluated. Median time to first shock was 97 s (IQR: 60-122.5 s) and did not correlate with provider factors, except previous experience with the defibrillator used in study. The number of providers who struggled (>10 s delay) with each of connecting the pads/paddles to the device, using pads/paddles on the mannequin and using buttons on the machine was 34 (50%), 26 (38%), and 31 (46%), respectively. Conclusions: The defibrillation skills of providers in a tertiary care children's hospital are poor. Both human and machine-related factors are associated with delay in defibrillation. Prior use of the study defibrillator is associated with a significantly shorter time-to-first shock as compared to prior use of any other defibrillator or no prior use of any defibrillator.

Sodium Nitroprusside Enhanced Cardiopulmonary Resuscitation Improves Short Term Survival in a Porcine Model of Ischemic Refractory Ventricular Fibrillation

PubMed Central

Yannopoulos, Demetris; Bartos, Jason A.; George, Stephen A.; Sideris, George; Voicu, Sebastian; Oestreich, Brett; Matsuura, Timothy; Shekar, Kadambari; Rees, Jennifer; Aufderheide, Tom P.

2017-01-01

Introduction Sodium nitroprusside (SNP) enhanced CPR (SNPeCPR) demonstrates increased vital organ blood flow and survival in multiple porcine models. We developed a new, coronary occlusion/ischemia model of prolonged resuscitation, mimicking the majority of out-of-hospital cardiac arrests presenting with shockable rhythms. Hypothesis SNPeCPR will increase short term (4-hour) survival compared to standard 2015 Advanced Cardiac Life Support (ACLS) guidelines in an ischemic refractory ventricular fibrillation (VF), prolonged CPR model. Methods Sixteen anesthetized pigs had the ostial left anterior descending artery occluded leading to ischemic VF arrest. VF was untreated for 5 minutes. Basic life support was performed for 10 minutes. At minute 10 (EMS arrival), animals received either SNPeCPR (n=8) or standard ACLS (n=8). Defibrillation (200J) occurred every 3 minutes. CPR continued for a total of 45 minutes, then the balloon was deflated simulating revascularization. CPR continued until return of spontaneous circulation (ROSC) or a total of 60 minutes, if unsuccessful. SNPeCPR animals received 2 mg of SNP at minute 10 followed by 1 mg every 5 minutes until ROSC. Standard ACLS animals received 0.5 mg epinephrine every 5 minutes until ROSC. Primary endpoints were ROSC and 4-hour survival. Results All SNPeCPR animals (8/8) achieved sustained ROSC versus 2/8 standard ACLS animals within one hour of resuscitation (p=0.04). The 4-hour survival was significantly improved with SNPeCPR compared to standard ACLS, 7/8 versus 1/8 respectively, p=0.0019. Conclusion SNPeCPR significantly improved ROSC and 4-hour survival compared with standard ACLS CPR in a porcine model of prolonged ischemic, refractory VF cardiac arrest. PMID:27771299

Sodium nitroprusside enhanced cardiopulmonary resuscitation improves short term survival in a porcine model of ischemic refractory ventricular fibrillation.

PubMed

Yannopoulos, Demetris; Bartos, Jason A; George, Stephen A; Sideris, George; Voicu, Sebastian; Oestreich, Brett; Matsuura, Timothy; Shekar, Kadambari; Rees, Jennifer; Aufderheide, Tom P

2017-01-01

Sodium nitroprusside (SNP) enhanced CPR (SNPeCPR) demonstrates increased vital organ blood flow and survival in multiple porcine models. We developed a new, coronary occlusion/ischemia model of prolonged resuscitation, mimicking the majority of out-of-hospital cardiac arrests presenting with shockable rhythms. SNPeCPR will increase short term (4-h) survival compared to standard 2015 Advanced Cardiac Life Support (ACLS) guidelines in an ischemic refractory ventricular fibrillation (VF), prolonged CPR model. Sixteen anesthetized pigs had the ostial left anterior descending artery occluded leading to ischemic VF arrest. VF was untreated for 5min. Basic life support was performed for 10min. At minute 10 (EMS arrival), animals received either SNPeCPR (n=8) or standard ACLS (n=8). Defibrillation (200J) occurred every 3min. CPR continued for a total of 45min, then the balloon was deflated simulating revascularization. CPR continued until return of spontaneous circulation (ROSC) or a total of 60min, if unsuccessful. SNPeCPR animals received 2mg of SNP at minute 10 followed by 1mg every 5min until ROSC. Standard ACLS animals received 0.5mg epinephrine every 5min until ROSC. Primary endpoints were ROSC and 4-h survival. All SNPeCPR animals (8/8) achieved sustained ROSC versus 2/8 standard ACLS animals within one hour of resuscitation (p=0.04). The 4-h survival was significantly improved with SNPeCPR compared to standard ACLS, 7/8 versus 1/8 respectively, p=0.0019. SNPeCPR significantly improved ROSC and 4-h survival compared with standard ACLS CPR in a porcine model of prolonged ischemic, refractory VF cardiac arrest. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Epicardial mapping of ventricular fibrillation over the posterior descending artery and left posterior papillary muscle of the swine heart.

PubMed

Nielsen, Thomas D; Huang, Jian; Rogers, Jack M; Killingsworth, Cheryl R; Ideker, Raymond E

2009-01-01

Recent studies suggest that during ventricular fibrillation (VF) epicardial vessels may be a site of conduction block and the posterior papillary muscle (PPM) in the left ventricle (LV) may be the location of a "mother rotor." The goal of this study was to obtain evidence to support or refute these possibilities. Epicardial activation over the posterior LV and right ventricle (RV) was mapped during the first 20 s of electrically induced VF in six open-chest pigs with a 504 electrode plaque covering a 20 cm(2) area centered over the posterior descending artery (PDA). The locations of epicardial breakthrough as well as reentry clustered in time and space during VF. Spatially, reentry occurred significantly more frequently over the LV than the RV in all 48 episodes, and breakthrough clustered near the PPM (p < 0.001). Significant temporal clustering occurred in 79% of breakthrough episodes and 100% of reentry episodes. These temporal clusters occurred at different times so that there was significantly less breakthrough when reentry was present (p < 0.0001). Conduction block occurred significantly more frequently near the PDA than elsewhere. The PDA is a site of epicardial block which may contribute to VF maintenance. Epicardial breakthrough clusters near the PPM. Reentry also clusters in space but at a separate site. The fact that breakthrough and reentry cluster at different locations and at different times supports the possibility of a drifting filament at the PPM so that at times reentry is present on the surface but at other times the reentrant wavefront breaks through to the epicardium.

Added value of cardiac magnetic resonance in etiological diagnosis of ventricular arrhythmias.

PubMed

Cabanelas, Nuno; Vidigal Ferreira, Maria João; Donato, Paulo; Gaspar, António; Pinto, Joana; Caseiro-Alves, Filipe; Providência, Luís Augusto

2013-10-01

Cardiac magnetic resonance (CMR) imaging is increasingly important in the diagnostic work-up of a wide range of heart diseases, including those with arrhythmogenic potential. To assess the added value of CMR in etiological diagnosis of ventricular arrhythmias after an inconclusive conventional investigation. Patients undergoing CMR between 2005 and 2011 for investigation of ventricular arrhythmias were included (n=113). All had documented arrhythmias. Those with a definite diagnosis from a previous investigation and those with evidence of coronary artery disease (acute coronary syndrome, typical angina symptoms, increase in biomarkers or positive stress test) were excluded. CMR results were considered relevant when they fulfilled diagnostic criteria. Of the 113 patients, 57.5% were male and mean age was 41.7 ± 16.2 years. Regarding the initial arrhythmia, 38.1% had ventricular fibrillation/sustained ventricular tachycardia (VF/VT) and 61.9% had less complex ventricular ectopy. CMR imaging showed criteria of a specific diagnosis in 42.5% of patients, was totally normal in 36.3%, and showed non-specific alterations in the remainder. In VF/VT patients, specific criteria were found in 60.4%, and in 31.4% of those with less complex ectopy. The most frequent diagnoses were arrhythmogenic right ventricular dysplasia, ventricular non-compaction and myopericarditis. It is worth noting that, although there was no evidence of previous coronary artery disease, 6.2% of patients had a late gadolinium enhancement distribution pattern compatible with myocardial infarction. CMR gives additional and important information in the diagnostic work-up of ventricular arrhythmias after an inconclusive initial investigation. The proportion of patients with diagnostic criteria was 42.5% (60.0% in those with VF/VT), and CMR was completely normal in 36.6%. Copyright © 2012 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Idiopathic anaphylaxis.

PubMed

Fenny, Nana; Grammer, Leslie C

2015-05-01

Idiopathic anaphylaxis is a diagnosis of exclusion after other causes have been thoroughly evaluated and excluded. The pathogenesis of idiopathic anaphylaxis remains uncertain, although increased numbers of activated lymphocytes and circulating histamine-releasing factors have been implicated. Signs and symptoms of patients diagnosed with idiopathic anaphylaxis are indistinguishable from the manifestations of other forms of anaphylaxis. Treatment regimens are implemented based on the frequency and severity of patient symptoms and generally include the use of epinephrine autoinjectors, antihistamines, and steroids. The prognosis of idiopathic anaphylaxis is generally favorable with well-established treatment regimens and effective patient education. Copyright © 2015 Elsevier Inc. All rights reserved.

The protective effect of H2-receptor activation against the duration of myocardial hypoxia/reoxygenation-induced ventricular fibrillation in sensitized guinea-pig hearts.

PubMed

Imajo, Naoki; Matsui, Saori; Yasui, Yumiko; Matsui, Nobuaki; Fukuishi, Nobuyuki; Akagi, Masaaki

2005-12-01

Patients with high serum immunoglobulin E levels were reported to be protected against sudden death during acute myocardial infarction. The protection mechanism might be attributed to the facilitation of histamine release from sensitized mast cells; however, this remains to be clarified. In this study, we examined the influence of sensitization on ventricular fibrillation (VF) induced by myocardial hypoxia/reoxygenation (H/R). Guinea pigs were actively sensitized by subcutaneous injection of ovalbumin in Bordetella pertussis vaccine. Hearts isolated from non-sensitized and sensitized guinea pigs were subjected to 30-min hypoxia / 30-min reoxygenation using a Langendorff apparatus. The amount of histamine released in the sensitized guinea-pig hearts was elevated, and the duration of VF was found to be reduced. The treatment with a histamine H2-receptor antagonist inhibited the reduction of VF duration. Treatment of the non-sensitized hearts with the histamine H2-receptor agonist resulted in the decrease of VF duration to the same level as that in the sensitized hearts. In conclusion, these results suggest that the risk of sudden death during myocardial H/R may be attenuated in the sensitized hearts and that histamine H2-receptor activation due to the released histamine may be involved in the protective effect.

Therapeutic effects of selective atrioventricular node vagal stimulation in atrial fibrillation and heart failure.

PubMed

Zhang, Youhua; Popović, Zoran B; Kusunose, Kenya; Mazgalev, Todor N

2013-01-01

Atrial fibrillation (AF) and heart failure (HF) frequently coexist. We have previously demonstrated that selective atrioventricular node (AVN) vagal stimulation (AVN-VS) can be used to control ventricular rate during AF. Due to withdrawal of vagal activity in HF, the therapeutic effects of AVN-VS may be compromised in the combined condition of AF and HF. Accordingly, this study was designed to evaluate the therapeutic effects of AVN-VS to control ventricular rate in AF and HF. A combined model of AF and HF was created by implanting a dual chamber pacemaker in 24 dogs. A newly designed bipolar electrode was inserted into the ganglionic AVN fat pad and connected to a nerve stimulator for delivering AVN-VS. In all dogs, HF was induced by high rate ventricular pacing at 220 bpm for 4 weeks. AF was then induced and maintained by rapid atrial pacing at 600 bpm after discontinuation of ventricular pacing. These HF + AF dogs were randomized into control (n = 9) and AVN-VS (n = 15) groups. In the latter group, vagal stimulation (310 μs, 20 Hz, 3-7 mA) was delivered continuously for 6 months. Compared with the control, AVN-VS had a consistent effect on ventricular rate slowing (by >50 bpm, all P < 0.001) during the entire 6-month observation period that was associated with left ventricular functional improvement. Moreover, AVN-VS was well tolerated by the treated animals. AVN-VS achieved consistent rate slowing, which was associated with improved ventricular function in a canine AF and HF model. Thus, AVN-VS may be a novel, effective therapeutic option in the combined condition of AF and HF. © 2012 Wiley Periodicals, Inc.

Atrioventricular and ventricular-to-ventricular programming in patients with cardiac resynchronization therapy: results from ALTITUDE.

PubMed

Steinberg, Benjamin A; Wehrenberg, Scott; Jackson, Kevin P; Hayes, David L; Varma, Niraj; Powell, Brian D; Day, John D; Frazier-Mills, Camille G; Stein, Kenneth M; Jones, Paul W; Piccini, Jonathan P

2015-12-01

Cardiac resynchronization therapy (CRT) improves outcomes in patients with heart failure, yet response rates are variable. We sought to determine whether physician-specified CRT programming was associated with improved outcomes. Using data from the ALTITUDE remote follow-up cohort, we examined sensed atrioventricular (AV) and ventricular-to-ventricular (VV) programming and their associated outcomes in patients with de novo CRT from 2009-2010. Outcomes included arrhythmia burden, left ventricular (LV) pacing, and all-cause mortality at 4 years. We identified 5709 patients with de novo CRT devices; at the time of implant, 34% (n = 1959) had entirely nominal settings programmed, 40% (n = 2294) had only AV timing adjusted, 11% (n = 604) had only VV timing adjusted, and 15% (n = 852) had both AV and VV adjusted from nominal programming. Suboptimal LV pacing (<95%) during follow-up was similar across groups; however, the proportion with atrial fibrillation (AF) burden >5% was lowest in the AV-only adjusted group (17.9%) and highest in the nominal (27.7%) and VV-only adjusted (28.3%) groups. Adjusted all-cause mortality was significantly higher among patients with non-nominal AV delay >120 vs. <120 ms (adjusted heart rate (HR) 1.28, p = 0.008) but similar when using the 180-ms cutoff (adjusted HR 1.13 for >180 vs. ≤180 ms, p = 0.4). Nominal settings for de novo CRT implants are frequently altered, most commonly the AV delay. There is wide variability in reprogramming. Patients with nominal or AV-only adjustments appear to have favorable pacing and arrhythmia outcomes. Sensed AV delays less than 120 ms are associated with improved survival.

Atrial Fibrillation: Complications

MedlinePlus

... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Complications Past Issues / Winter 2015 Table of Contents ... has two major complications—stroke and heart failure. Atrial Fibrillation and Stroke Click to enlarge image This illustration ...

Inferior J waves in patients with vasospastic angina might be a risk factor for ventricular fibrillation.

PubMed

Fumimoto, Tomoko; Ueyama, Takeshi; Shimizu, Akihiko; Yoshiga, Yasuhiro; Ono, Makoto; Kato, Takayoshi; Ishiguchi, Hironori; Okamura, Takayuki; Yamada, Jutaro; Yano, Masafumi

2017-09-01

There is little information about the relationship between J waves and the occurrence of ventricular fibrillation (VF) in patients with vasospastic angina (VSA). The present study aimed to assess the incidence of J waves and the occurrence of VF in patients with VSA. The subjects consisted of 62 patients with VSA diagnosed by acetylcholine provocation tests in our institution from 2002 to 2014. We investigated the VF events, prevalence of J waves, and relationship between the VF events and J waves. J waves were observed in 16 patients (26%) and VF events were documented in 11 (18%). The incidence of VF in the patients with J waves was significantly higher than that in those without J waves (38% vs 11%, p=0.026). J waves were observed in the inferior leads in 14 patients, lateral leads in 5, and anterior leads in 3. A univariate analysis indicated that the incidence of VF in the inferior leads of J wave positive patients (46%=6/14) was significantly (p=0.01) higher than that in the inferior leads of J wave negative patients (10%=5/48). The J waves in the anterior and/or lateral leads were not related to the incidence of VF. Notched type and slurred type J waves were not associated with VF. A multivariate analysis revealed that J waves in VSA patients were associated with VF [odds ratio (OR) 6.41, 95% confidence interval (CI) 1.37-29.93, p=0.02] and organic stenosis (OR 6.98, 95% CI 1.39-35.08, p=0.02). Further, J waves in the inferior leads were strongly correlated with VF (OR 11.85, 95% CI 2.05-68.42, p=0.006). The results suggest that the existence of J waves, especially in the inferior leads, might be a risk factor for VF in VSA patients. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Electrocardiographic characteristics of left ventricular outflow tract tachycardia.

PubMed

Hachiya, H; Aonuma, K; Yamauchi, Y; Harada, T; Igawa, M; Nogami, A; Iesaka, Y; Hiroe, M; Marumo, F

2000-11-01

Catheter ablation of idiopathic left ventricular outflow tract tachycardia (LVOT-VT) is rare because a safe ablation technique at this site has not been described, and serious complications may occur. This study compared the QRS morphology of LVOT-VT with that of idiopathic right ventricular outflow tract tachycardia. A comparison was made between the electrocardiographic characteristics of LVOT-VT originating from the supravalvular region of a coronary cusp (Supra-Ao group) with those of LVOT-VT originating from the infravalvular endocardial region of a coronary cusp of the aortic valve within the LV (Infra-Ao group). After precise mapping of the right ventricle, left ventricle, pulmonary artery, coronary cusps, and proximal portion of the anterior interventricular vein, there were 17 patients in whom VT was thought to be located at the LVOT by both activation and pace mapping. They were divided between a Supra-Ao group (n = 8), and an Infra-Ao group (n = 9). Analysis of the 12-lead electrocardiogram (ECG) revealed an S wave in lead I in all 17 patients. A precordial R wave transition was also observed at V1 or V2 in 16 patients (94%). In 7 of 8 patients (88%) with Supra-Ao LVOT-VT, no S wave was observed in either V5 or V6. In contrast, an Rs pattern was observed in both V5 and V6, or in V6 only, in 100% of the patients with Infra-Ao LVOT-VT. A LVOT-VT should be suspected when the ECG shows an S wave in lead I and an R/S ratio greater than 1 in lead V1 or V2, versus a coronary cusp location if there is no S wave in either lead V5 or V6.

A rabbit ventricular action potential model replicating cardiac dynamics at rapid heart rates.

PubMed

Mahajan, Aman; Shiferaw, Yohannes; Sato, Daisuke; Baher, Ali; Olcese, Riccardo; Xie, Lai-Hua; Yang, Ming-Jim; Chen, Peng-Sheng; Restrepo, Juan G; Karma, Alain; Garfinkel, Alan; Qu, Zhilin; Weiss, James N

2008-01-15

Mathematical modeling of the cardiac action potential has proven to be a powerful tool for illuminating various aspects of cardiac function, including cardiac arrhythmias. However, no currently available detailed action potential model accurately reproduces the dynamics of the cardiac action potential and intracellular calcium (Ca(i)) cycling at rapid heart rates relevant to ventricular tachycardia and fibrillation. The aim of this study was to develop such a model. Using an existing rabbit ventricular action potential model, we modified the L-type calcium (Ca) current (I(Ca,L)) and Ca(i) cycling formulations based on new experimental patch-clamp data obtained in isolated rabbit ventricular myocytes, using the perforated patch configuration at 35-37 degrees C. Incorporating a minimal seven-state Markovian model of I(Ca,L) that reproduced Ca- and voltage-dependent kinetics in combination with our previously published dynamic Ca(i) cycling model, the new model replicates experimentally observed action potential duration and Ca(i) transient alternans at rapid heart rates, and accurately reproduces experimental action potential duration restitution curves obtained by either dynamic or S1S2 pacing.

Cor triatriatum sinister identified after new onset atrial fibrillation in an elderly man.

PubMed

Zepeda, Ignacio A; Morcos, Peter; Castellanos, Luis R

2014-01-01

A 73-year-old man with new onset atrial fibrillation with rapid ventricular response underwent transthoracic echocardiography that revealed an echogenic linear structure along the left atrium, suggestive of cor triatriatum sinister (CTS). CTS was confirmed with transesophageal echocardiography which demonstrated a proximal accessory atrium receiving pulmonary venous flow separated from a distal true atrium by a fibromuscular membrane with a large fenestration allowing flow between the chambers. In CTS, the left atrium is divided into proximal and distal chambers by a fenestrated fibromuscular septum. This cardiac anomaly accounts for 0.1% of cases of congenital heart disease and rarely presents in adults. CTS is primarily diagnosed with echocardiography and is associated with left atrial enlargement and development of atrial fibrillation. Treatment options depend on size of the communication between proximal and distal chambers, the gradient across the membrane, and the position of pulmonary veins. In some instances, surgical resection of the membrane that divides the left atrium is warranted.

Cor Triatriatum Sinister Identified after New Onset Atrial Fibrillation in an Elderly Man

PubMed Central

Zepeda, Ignacio A.; Morcos, Peter; Castellanos, Luis R.

2014-01-01

A 73-year-old man with new onset atrial fibrillation with rapid ventricular response underwent transthoracic echocardiography that revealed an echogenic linear structure along the left atrium, suggestive of cor triatriatum sinister (CTS). CTS was confirmed with transesophageal echocardiography which demonstrated a proximal accessory atrium receiving pulmonary venous flow separated from a distal true atrium by a fibromuscular membrane with a large fenestration allowing flow between the chambers. In CTS, the left atrium is divided into proximal and distal chambers by a fenestrated fibromuscular septum. This cardiac anomaly accounts for 0.1% of cases of congenital heart disease and rarely presents in adults. CTS is primarily diagnosed with echocardiography and is associated with left atrial enlargement and development of atrial fibrillation. Treatment options depend on size of the communication between proximal and distal chambers, the gradient across the membrane, and the position of pulmonary veins. In some instances, surgical resection of the membrane that divides the left atrium is warranted. PMID:25614746

Early prognostic value of an Algorithm based on spectral Variables of Ventricular fibrillAtion from the EKG of patients with suddEn cardiac death: A multicentre observational study (AWAKE).

PubMed

Palacios-Rubio, Julián; Marina-Breysse, Manuel; Quintanilla, Jorge G; Gil-Perdomo, José Miguel; Juárez-Fernández, Miriam; Garcia-Gonzalez, Inés; Rial-Bastón, Verónica; Corcobado, María Carmen; Espinosa, María Carmen; Ruiz, Francisco; Gómez-Mascaraque Pérez, Francisco; Bringas-Bollada, María; Lillo-Castellano, José María; Pérez-Castellano, Nicasio; Martínez-Sellés, Manuel; López de Sá, Esteban; Martín-Benítez, Juan Carlos; Perez-Villacastín, Julián; Filgueiras-Rama, David

2018-06-06

Ventricular fibrillation (VF)-related sudden cardiac death (SCD) is a leading cause of mortality and morbidity. Current biological and imaging parameters show significant limitations on predicting cerebral performance at hospital admission. The AWAKE study (NCT03248557) is a multicentre observational study to validate a model based on spectral ECG analysis to early predict cerebral performance and survival in resuscitated comatose survivors. Data from VF ECG tracings of patients resuscitated from SCD will be collected using an electronic Case Report Form. Patients can be either comatose (Glasgow Coma Scale - GCS - ≤8) survivors undergoing temperature control after return of spontaneous circulation (RoSC), or those who regain consciousness (GCS=15) after RoSC; all admitted to Intensive Cardiac Care Units in 4 major university hospitals. VF tracings prior to the first direct current shock will be digitized and analyzed to derive spectral data and feed a predictive model to estimate favorable neurological performance (FNP). The results of the model will be compared to the actual prognosis. The primary clinical outcome is FNP during hospitalization. Patients will be categorized into 4 subsets of neurological prognosis according to the risk score obtained from the predictive model. The secondary clinical outcomes are survival to hospital discharge, and FNP and survival after 6 months of follow-up. The model-derived categorisation will be also compared with clinical variables to assess model sensitivity, specificity, and accuracy. A model based on spectral analysis of VF tracings is a promising tool to obtain early prognostic data after SCD. Copyright © 2018 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

Association of ventricular arrhythmia and in-hospital mortality in stroke patients in Florida: A nonconcurrent prospective study.

PubMed

Dahlin, Arielle A; Parsons, Chase C; Barengo, Noël C; Ruiz, Juan Gabriel; Ward-Peterson, Melissa; Zevallos, Juan Carlos

2017-07-01

Stroke remains one of the leading causes of death in the United States. Current evidence identified electrocardiographic abnormalities and cardiac arrhythmias in 50% of patients with an acute stroke. The purpose of this study was to assess whether the presence of ventricular arrhythmia (VA) in adult patients hospitalized in Florida with acute stroke increased the risk of in-hospital mortality.Secondary data analysis of 215,150 patients with ischemic and hemorrhagic stroke hospitalized in the state of Florida collected by the Florida Agency for Healthcare Administration from 2008 to 2012. The main outcome for this study was in-hospital mortality. The main exposure of this study was defined as the presence of VA. VA included the ICD-9 CM codes: paroxysmal ventricular tachycardia (427.1), ventricular fibrillation (427.41), ventricular flutter (427.42), ventricular fibrillation and flutter (427.4), and other - includes premature ventricular beats, contractions, or systoles (427.69). Differences in demographic and clinical characteristics and hospital outcomes were assessed between patients who developed versus did not develop VA during hospitalization (χ and t tests). Binary logistic regression was used to estimate unadjusted and adjusted odds ratios and 95% confidence intervals (CIs) between VA and in-hospital mortality.VA was associated with an increased risk of in-hospital mortality after adjusting for all covariates (odds ratio [OR]: 1.75; 95% CI: 1.6-1.2). There was an increased in-hospital mortality in women compared to men (OR: 1.1; 95% CI: 1.1-1.14), age greater than 85 years (OR: 3.9, 95% CI: 3.5-4.3), African Americans compared to Whites (OR: 1.1; 95% CI: 1.04-1.2), diagnosis of congestive heart failure (OR: 2.1; 95% CI: 2.0-2.3), and atrial arrhythmias (OR: 2.1, 95% CI: 2.0-2.2). Patients with hemorrhagic stroke had increased odds of in-hospital mortality (OR: 9.0; 95% CI: 8.6-9.4) compared to ischemic stroke.Identifying VAs in stroke patients may help in

Atrial Tachycardias Following Atrial Fibrillation Ablation

PubMed Central

Sághy, László; Tutuianu, Cristina; Szilágyi, Judith

2015-01-01

One of the most important proarrhythmic complications after left atrial (LA) ablation is regular atrial tachycardia (AT) or flutter. Those tachycardias that occur after atrial fibrillation (AF) ablation can cause even more severe symptoms than those from the original arrhythmia prior to the index ablation procedure since they are often incessant and associated with rapid ventricular response. Depending on the method and extent of LA ablation and on the electrophysiological properties of underlying LA substrate, the reported incidence of late ATs is variable. To establish the exact mechanism of these tachycardias can be difficult and controversial but correlates with the ablation technique and in the vast majority of cases the mechanism is reentry related to gaps in prior ablation lines. When tachycardias occur, conservative therapy usually is not effective, radiofrequency ablation procedure is mostly successful, but can be challenging, and requires a complex approach. PMID:25308808

Idiopathic Ophthalmodynia and Idiopathic Rhinalgia: A Prospective Series of 16 New Cases.

PubMed

Pareja, Juan A; Montojo, Teresa; Guerrero, Ángel L; Álvarez, Mónica; Porta-Etessam, Jesús; Cuadrado, María L

2015-01-01

Idiopathic ophthalmodynia and idiopathic rhinalgia were described a few years ago. These conditions seem specific pain syndromes with a distinctive location in the eye or in the nose. We aimed to present a new prospective series in order to verify the consistency of these syndromes. We performed a descriptive study of all patients referred to our regional neurologic clinics from 2010 to 2014 because of facial pain exclusively felt in the eye or in the nose fulfilling the proposed diagnostic criteria for idiopathic ophthalmodynia and idiopathic rhinalgia. There were 9 patients with idiopathic ophthalmodynia and 7 patients with idiopathic rhinalgia, with a clear female preponderance, and a mean age at onset in the fifth decade. The pain was usually moderate and the temporal pattern was generally chronic. Only one patient reported accompaniments (hypersensitivity to the light and to the flow of air in the symptomatic eye). Preventive treatment with amitriptyline, pregabalin, or gabapentin was partially or totally effective. The clinical features of this new series parallels those of the original description, thus indicating that both idiopathic ophthalmodynia and idiopathic rhinalgia have clear-cut clinical pictures with excellent consistency both inter- and intra-individually. © 2015 American Headache Society.

Optical mapping of Langendorff-perfused human hearts: establishing a model for the study of ventricular fibrillation in humans.

PubMed

Nanthakumar, Kumaraswamy; Jalife, José; Massé, Stéphane; Downar, Eugene; Pop, Mihaela; Asta, John; Ross, Heather; Rao, Vivek; Mironov, Sergey; Sevaptsidis, Elias; Rogers, Jack; Wright, Graham; Dhopeshwarkar, Rajesh

2007-07-01

Our objective was to establish a novel model for the study of ventricular fibrillation (VF) in humans. We adopted the established techniques of optical mapping to human ventricles for the first time to determine whether human VF is the result of wave breaks and singularity point formation and is maintained by high-frequency rotors and fibrillatory conduction. We describe the technique of acquiring optical signals in human hearts during VF, their characteristics, and the feasibility of possible analyses that could be performed to elucidate mechanisms of human VF. We used explanted hearts from five cardiomyopathic patients who underwent transplantation. The hearts were Langendorff perfused with Tyrode solution (95% O(2)-5% CO(2)), and the potentiometric dye di-4-ANEPPS was injected as a bolus into the coronary circulation. Fluorescence was excited at 531 +/- 20 nm with a 150-W halogen light source; the emission signal was long-pass filtered at 610 nm and recorded with a mapping camera. Fractional change of fluorescence varied between 2% and 12%. Average signal-to-noise ratio was 40 dB. The mean velocity of VF wave fronts was 0.25 +/- 0.04 m/s. Submillimetric spatial resolution (0.65-0.85 mm), activation mapping, and transformation of the data to phase-based analysis revealed reentrant, colliding, and fractionating wave fronts in human VF. On many occasions the VF wave fronts were as large as the entire vertical length (8 cm) of the mapping field, suggesting that there are a limited number of wave fronts on the human heart during VF. Phase transformation of the optical signals allowed the first demonstration ever of phase singularity point, wave breaks, and rotor formation in human VF. This method provides opportunities for potential analyses toward elucidation of the mechanisms of VF and defibrillation in humans.

Does the choice of definition for defibrillation and CPR success impact the predictability of ventricular fibrillation waveform analysis?

PubMed

Jin, Danian; Dai, Chenxi; Gong, Yushun; Lu, Yubao; Zhang, Lei; Quan, Weilun; Li, Yongqin

2017-02-01

Quantitative analysis of ventricular fibrillation (VF), such as amplitude spectral area (AMSA), predicts shock outcomes. However, there is no uniform definition of shock/cardiopulmonary resuscitation (CPR) success in out-of-hospital cardiac arrest (OHCA). The objective of this study is to investigate post-shock rhythm variations and the impact of shock/CPR success definition on the predictability of AMSA. A total of 554 shocks from 257 OHCA patients with VF as initial rhythm were analyzed. Post-shock rhythms were analyzed every 5s up to 120s and annotated as VF, asystole (AS) and organized rhythm (OR) at serial time intervals. Three shock/CPR success definitions were used to evaluate the predictability of AMSA: (1) termination of VF (ToVF); (2) return of organized electrical activity (ROEA); (3) return of potentially perfusing rhythm (RPPR). Rhythm changes occurred after 54.5% (N=302) of shocks and 85.8% (N=259) of them occurred within 60s after shock delivery. The observed post-shock rhythm changes were (1) from AS to VF (24.9%), (2) from OR to VF (16.1%), and (3) from AS to OR (12.1%). The area under the receiver operating characteristic curve (AUC) for AMSA as a predictor of shock/CPR success reached its maximum 60s post-shock. The AUC was 0.646 for ToVF, 0.782 for ROEA, and 0.835 for RPPR (p<0.001) respectively. Post-shock rhythm is unstable in the first minute after the shock. The predictability of AMSA varies depending on the definition of shock/CPR success and performs best with the return of potentially perfusing rhythm endpoint for OHCA. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Blood Pressure and Coronary Perfusion Pressure Targeted Cardiopulmonary Resuscitation Improves 24-Hour Survival from Ventricular Fibrillation Cardiac Arrest

PubMed Central

Maryam, Y.; Sutton, Robert M.; Friess, Stuart H.; Bratinov, George; Bhalala, Utpal; Kilbaugh, Todd J.; Lampe, Joshua; Nadkarni, Vinay M.; Becker, Lance B.; Berg, Robert A.

2016-01-01

Objective Treatment algorithms for cardiac arrest are rescuer-centric and vary little from patient to patient. The objective of this study was to determine if cardiopulmonary resuscitation (CPR) targeted to arterial blood pressure and coronary perfusion pressure (CPP) rather than optimal Guideline Care would improve 24-hour survival in a porcine model of ventricular fibrillation (VF) cardiac arrest. Design Randomized interventional study Setting Preclinical animal laboratory Subjects Female 3-month old swine Interventions/Measurements After induction of anesthesia and 7 minutes of untreated VF, 16 female 3-month old swine were randomized to: 1) Blood Pressure (BP) care: titration of chest compression (CC) depth to a systolic blood pressure (SBP) of 100 mmHg and vasopressor dosing to maintain CPP >20mmHg or 2) Guideline care: CC depth targeted to 51 mm and standard Guideline vasopressor dosing. Animals received manual CPR for 10 minutes before the first defibrillation attempt and standardized post-resuscitation care for 24 hours. Main Results 24-hour survival was more likely with BP care versus Guideline care (0/8 versus 5/8, p<0.03), and all survivors had normal neurological examinations. Mean CPP prior to defibrillation was significantly higher with BP care (28±3 mmHg versus 10±6 mmHg, p<0.01). CC depth was lower with BP care (48±0.4 mmHg versus 44±0.5 mmHg, p<0.05) and number of vasopressor doses was higher with BP care (median 3 [range 1-7] versus 2 [range 2-2], p<0.01). Conclusions Individualized goal-directed hemodynamic resuscitation targeting SBP of 100 mmHg and CPP >20 mmHg improved 24-hour survival compared to Guideline care in this model of VF cardiac arrest. PMID:27414479

Idiopathic remitting seronegative symmetrical synovitis with pitting edema syndrome associated with bilateral pleural and pericardial effusions: a case report.

PubMed

Yanamoto, Shozaburo; Fukae, Jiro; Fukiyama, Yurie; Fujioka, Shinsuke; Ouma, Shinji; Tsuboi, Yoshio

2016-07-20

Remitting seronegative symmetrical synovitis with pitting edema syndrome is characterized by symmetrical synovitis with pitting edema in the dorsum of the hands or feet. Most cases of remitting seronegative symmetrical synovitis with pitting edema syndrome are idiopathic, but some are secondary to malignancy, autoimmune disease, or neurodegenerative disorders. Pleural and pericardial effusions are unusual complications in idiopathic remitting seronegative symmetrical synovitis with pitting edema syndrome. A 74-year-old Japanese woman presented to our hospital with arthralgia and pitting edema in her feet. She had pain in multiple joints, peripheral edema, and a markedly elevated erythrocyte sedimentation rate. Enhanced computed tomography and laboratory data showed no evidence of malignancy. These findings suggested that she had idiopathic remitting seronegative symmetrical synovitis with pitting edema syndrome. She also developed respiratory distress because of bilateral pleural and pericardial effusions. Laboratory data showed that serum vascular endothelial growth factor and interleukin-6 were significantly elevated. After administration of steroids, her pleural and pericardial effusions decreased and finally disappeared. Furthermore, vascular endothelial growth factor and interleukin-6 decreased when the pleural and pericardial effusions disappeared. Here we report the case of a patient with idiopathic remitting seronegative symmetrical synovitis with pitting edema syndrome associated with life-threatening complications, including bilateral pleural and pericardial effusions during the course of the illness, which led to respiratory failure and atrial fibrillation. Elevated vascular endothelial growth factor and interleukin-6 may be associated with the cause of pleural and pericardial effusions in idiopathic remitting seronegative symmetrical synovitis with pitting edema syndrome.

Characteristics of ventricular fibrillation in relation to cardiac aetiology and shock success: A waveform analysis study in ICD-patients.

PubMed

Bonnes, Judith L; Keuper, Wessel; Westra, Sjoerd W; Zegers, Erwin S; Oostendorp, Thom F; Brouwer, Marc A; Smeets, Joep L R M

2015-01-01

Ventricular fibrillation (VF) waveform characteristics are associated with cardiac arrest duration and defibrillation success. Recent animal studies found that VF characteristics and shock success also depend on the presence of myocardial infarction (MI). In patients, VF induction after implantable cardioverter defibrillator (ICD) implantation offers a unique setting to study early VF characteristics: we studied the relation with cardiac disease--either presence or absence of a previous MI--and with shock success. Retrospective cohort study of ICD-patients who underwent defibrillation testing, 117 (63%) with and 69 (37%) without a previous MI. Intracardiac recordings of induced VF were analysed using Fourier analysis. In previous MI-patients, the fundamental frequency and organisation index of the VF signal were significantly lower as compared with patients without a previous MI: 4.9 Hz ± 0.6 vs. 5.2 Hz ± 0.6 (p = 0.005) and 56% ± 10 vs. 60% ± 9 (p = 0.001), respectively. The median frequency was not different (p = 0.25). We found no association between VF characteristics and ICD shock success. In analogy with observations in animals, we found that a history of a previous MI was associated with slower and less organised VF. In our cohort of ICD-patients, early VF waveform characteristics were not associated with shock outcomes. Further study is warranted to determine to what extent VF characteristics are influenced by the underlying aetiology on the one hand, and time delay on the other. These findings could improve insight into the potential value of VF analysis to guide shock delivery. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Epicardial mapping of ventricular fibrillation over the posterior descending artery and left posterior papillary muscle of the swine heart

PubMed Central

Nielsen, Thomas D.; Huang, Jian; Rogers, Jack M.; Killingsworth, Cheryl R.

2008-01-01

Background Recent studies suggest that during ventricular fibrillation (VF) epicardial vessels may be a site of conduction block and the posterior papillary muscle (PPM) in the left ventricle (LV) may be the location of a “mother rotor.” The goal of this study was to obtain evidence to support or refute these possibilities. Methods Epicardial activation over the posterior LV and right ventricle (RV) was mapped during the first 20 s of electrically induced VF in six open-chest pigs with a 504 electrode plaque covering a 20 cm2 area centered over the posterior descending artery (PDA). Results The locations of epicardial breakthrough as well as reentry clustered in time and space during VF. Spatially, reentry occurred significantly more frequently over the LV than the RV in all 48 episodes, and breakthrough clustered near the PPM (p<0.001). Significant temporal clustering occurred in 79% of breakthrough episodes and 100% of reentry episodes. These temporal clusters occurred at different times so that there was significantly less breakthrough when reentry was present (p<0.0001). Conduction block occurred significantly more frequently near the PDA than elsewhere. Conclusions The PDA is a site of epicardial block which may contribute to VF maintenance. Epicardial breakthrough clusters near the PPM. Reentry also clusters in space but at a separate site. The fact that breakthrough and reentry cluster at different locations and at different times supports the possibility of a drifting filament at the PPM so that at times reentry is present on the surface but at other times the reentrant wavefront breaks through to the epicardium. PMID:18839296

Inflammatory biomarkers are not predictive of intermediate-term risk of ventricular tachyarrhythmias in stable CHF patients.

PubMed

Konstantino, Yuval; Kusniec, Jairo; Reshef, Tamar; David-Zadeh, Ofer; Mazur, Alexander; Strasberg, Boris; Battler, Alexander; Haim, Moti

2007-08-01

Elevated levels of inflammatory biomarkers and brain natriuretic peptide (BNP) are associated with increased mortality in patients with heart failure (HF). : The aim of the current study was to assess the correlation between circulating biomarkers and ventricular tachyarrhythmias among patients with HF. Blood samples from 50 stable ambulatory HF patients with moderate to severe systolic left ventricular (LV) dysfunction and an implantable cardioverter defibrillator (ICD) were analyzed for interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), high-sensitivity C-reactive protein (hsCRP) and BNP. Thereafter, the patients were followed for a mean period of 152 +/- 44 days, during which ventricular tachyarrhythmias were recorded by the ICDs. Follow-up data were obtained from 47 patients. Of them, 45 (96%) had ischemic cardiomyopathy, 38 (81%) had New York Heart Association class I-II, 43 (91%) were males, and the mean age was 68.6 +/- 11.1 years. During follow-up, 5 patients (11%) had nonsustained ventricular tachycardia (NSVT), 6 patients (13%) had sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and 36 patients (76%) had no events. The circulating biomarkers' levels upon enrollment were not significantly different between patients who subsequently had NSVT or VT/VF and patients who were free of events. No correlation was found between plasma levels of IL-6, TNF-alpha, hsCRP and BNP and ventricular arrhythmic events among stable HF patients during an intermediate term follow-up of 5.1 months. Further studies are still required to assess the association between these biomarkers and long-term risk of ventricular tachyarrhythmia. (c) 2007 Wiley Periodicals, Inc.

Bilirubin attenuates bufadienolide-induced ventricular arrhythmias and cardiac dysfunction in guinea-pigs by reducing elevated intracellular Na(+) levels.

PubMed

Ma, Hongyue; Zhang, Junfeng; Jiang, Jiejun; Zhou, Jing; Xu, Huiqin; Zhan, Zhen; Wu, Qinan; Duan, Jinao

2012-03-01

Bufadienolides, known ligands of the sodium pump, have been shown to inhibit the proliferation of several cancer cell types. However, their development to date as anticancer agents has been impaired by a narrow therapeutic margin resulting from their potential to induce cardiotoxicity. In the present study, we examined the effects of bilirubin, an endogenous antioxidant, on the cardiotoxicity of bufadienolides (derived from toad venom) in guinea-pigs. The results showed that bufadienolides (8 mg/kg) caused ventricular arrhythmias, conduction block, cardiac dysfunction and death in guinea-pigs. Pretreatment with bilirubin (75 and 150 mg/kg) significantly prevented bufadienolide-induced premature ventricular complexes, ventricular tachycardia, ventricular fibrillation and death. Bilirubin also markedly improved the inhibition of cardiac contraction in bufadienolide-treated guinea-pigs as evidenced by increases in left ventricular systolic pressure and decreases in left ventricular diastolic pressure in vivo. Furthermore, bilirubin significantly reduced the intracellular sodium content ([Na(+)]( i )) in ex vivo bufadienolide-stimulated guinea-pig ventricular myocytes loaded with the sodium indicator Sodium Green. An antitumor study showed that bilirubin did not compromise the ability of bufadienolides to inhibit gastric cancer cell MGC-803 proliferation. These results suggested that bilirubin can attenuate bufadienolide-induced arrhythmias and cardiac dysfunction in guinea-pigs by reducing elevated [Na(+)]( i ) and may improve bufadienolide therapeutic index in cancer treatment.

Factors related to outcome in heart failure with a preserved (or normal) left ventricular ejection fraction.

PubMed

Sanderson, John E

2016-07-01

Heart failure with a preserved ejection faction (HFpEF) is a growing and expensive cause of heart failure (HF) affecting particularly the elderly. It differs in substantial ways in addition to the normal left ventricular ejection fraction, from the more easily recognized form of heart failure with a reduced ejection fraction (HFrEF or 'systolic heart failure') and unlike HFrEF there have been little advances in treatment. In part, this relates to the complexity of the pathophysiology and identifying the correct targets. In HFpEF, there appears to be widespread stiffening of the vasculature and the myocardium affecting ventricular function (both systolic and diastolic), impeding ventricular suction, and thus early diastolic filling leading to breathlessness on exertion and later atrial failure and fibrillation. Left ventricular ejection fraction tends to gradually decline and some evolve into HFrEF. Most patients also have a mixture of several co-morbidities including hypertension, diabetes, obesity, poor renal function, lack of fitness, and often poor social conditions. Therefore, many factors may influence outcome in an individual patient. In this review, the epidemiology, possible causation, pathophysiology, the influence of co-morbidities and some of the many potential predictors of outcome will be considered.

FibrilJ: ImageJ plugin for fibrils' diameter and persistence length determination

NASA Astrophysics Data System (ADS)

Sokolov, P. A.; Belousov, M. V.; Bondarev, S. A.; Zhouravleva, G. A.; Kasyanenko, N. A.

2017-05-01

Application of microscopy to evaluate the morphology and size of filamentous proteins and amyloids requires new and creative approaches to simplify and automate the image processing. The estimation of mean values of fibrils diameter, length and bending stiffness on micrographs is a major challenge. For this purpose we developed an open-source FibrilJ plugin for the ImageJ/FiJi program. It automatically recognizes the fibrils on the surface of a mica, silicon, gold or formvar film and further analyzes them to calculate the distribution of fibrils by diameters, lengths and persistence lengths. The plugin has been validated by the processing of TEM images of fibrils formed by Sup35NM yeast protein and artificially created images of rod-shape objects with predefined parameters. Novel data obtained by SEM for Sup35NM protein fibrils immobilized on silicon and gold substrates are also presented and analyzed.

Glymphatic MRI in idiopathic normal pressure hydrocephalus

PubMed Central

Ringstad, Geir; Vatnehol, Svein Are Sirirud; Eide, Per Kristian

2017-01-01

Abstract The glymphatic system has in previous studies been shown as fundamental to clearance of waste metabolites from the brain interstitial space, and is proposed to be instrumental in normal ageing and brain pathology such as Alzheimer’s disease and brain trauma. Assessment of glymphatic function using magnetic resonance imaging with intrathecal contrast agent as a cerebrospinal fluid tracer has so far been limited to rodents. We aimed to image cerebrospinal fluid flow characteristics and glymphatic function in humans, and applied the methodology in a prospective study of 15 idiopathic normal pressure hydrocephalus patients (mean age 71.3 ± 8.1 years, three female and 12 male) and eight reference subjects (mean age 41.1 + 13.0 years, six female and two male) with suspected cerebrospinal fluid leakage (seven) and intracranial cyst (one). The imaging protocol included T1-weighted magnetic resonance imaging with equal sequence parameters before and at multiple time points through 24 h after intrathecal injection of the contrast agent gadobutrol at the lumbar level. All study subjects were kept in the supine position between examinations during the first day. Gadobutrol enhancement was measured at all imaging time points from regions of interest placed at predefined locations in brain parenchyma, the subarachnoid and intraventricular space, and inside the sagittal sinus. Parameters demonstrating gadobutrol enhancement and clearance in different locations were compared between idiopathic normal pressure hydrocephalus and reference subjects. A characteristic flow pattern in idiopathic normal hydrocephalus was ventricular reflux of gadobutrol from the subarachnoid space followed by transependymal gadobutrol migration. At the brain surfaces, gadobutrol propagated antegradely along large leptomeningeal arteries in all study subjects, and preceded glymphatic enhancement in adjacent brain tissue, indicating a pivotal role of intracranial pulsations for glymphatic

Glymphatic MRI in idiopathic normal pressure hydrocephalus.

PubMed

Ringstad, Geir; Vatnehol, Svein Are Sirirud; Eide, Per Kristian

2017-10-01

The glymphatic system has in previous studies been shown as fundamental to clearance of waste metabolites from the brain interstitial space, and is proposed to be instrumental in normal ageing and brain pathology such as Alzheimer's disease and brain trauma. Assessment of glymphatic function using magnetic resonance imaging with intrathecal contrast agent as a cerebrospinal fluid tracer has so far been limited to rodents. We aimed to image cerebrospinal fluid flow characteristics and glymphatic function in humans, and applied the methodology in a prospective study of 15 idiopathic normal pressure hydrocephalus patients (mean age 71.3 ± 8.1 years, three female and 12 male) and eight reference subjects (mean age 41.1 + 13.0 years, six female and two male) with suspected cerebrospinal fluid leakage (seven) and intracranial cyst (one). The imaging protocol included T1-weighted magnetic resonance imaging with equal sequence parameters before and at multiple time points through 24 h after intrathecal injection of the contrast agent gadobutrol at the lumbar level. All study subjects were kept in the supine position between examinations during the first day. Gadobutrol enhancement was measured at all imaging time points from regions of interest placed at predefined locations in brain parenchyma, the subarachnoid and intraventricular space, and inside the sagittal sinus. Parameters demonstrating gadobutrol enhancement and clearance in different locations were compared between idiopathic normal pressure hydrocephalus and reference subjects. A characteristic flow pattern in idiopathic normal hydrocephalus was ventricular reflux of gadobutrol from the subarachnoid space followed by transependymal gadobutrol migration. At the brain surfaces, gadobutrol propagated antegradely along large leptomeningeal arteries in all study subjects, and preceded glymphatic enhancement in adjacent brain tissue, indicating a pivotal role of intracranial pulsations for glymphatic function. In

Rate-dependent Loss of Capture during Ventricular Pacing.

PubMed

Wang, Jingfeng; Chen, Haiyan; Su, Yangang; Ge, Junbo

2015-01-01

A 63-year-old patient who had undergone atrial septal defect surgical repair received implantation of a single chamber VVI pacemaker for long RR intervals during atrial fibrillation. One week later, an intermittent loss of capture and sensing failure was detected at a pacing rate of 70 beats/min. However, a successful capture was observed during rapid pacing. Consequently, the pacing rate was temporarily adjusted to 90 beats/min. At the 3-month follow-up, the pacemaker was shown to be functioning properly independent of the pacing rate. An echocardiogram showed that the increased pacing rates were accompanied by a reduction in the right ventricular outflow tract dimension. The pacemaker was then permanently programmed at a lower rate of 60 beats/min.

Electrical alternans during rest and exercise as predictors of vulnerability to ventricular arrhythmias

NASA Technical Reports Server (NTRS)

Estes, N. A. 3rd; Michaud, G.; Zipes, D. P.; El-Sherif, N.; Venditti, F. J.; Rosenbaum, D. S.; Albrecht, P.; Wang, P. J.; Cohen, R. J.

1997-01-01

This investigation was performed to evaluate the feasibility of detecting repolarization alternans with the heart rate elevated with a bicycle exercise protocol. Sensitive spectral signal-processing techniques are able to detect beat-to-beat alternation of the amplitude of the T wave, which is not visible on standard electrocardiogram. Previous animal and human investigations using atrial or ventricular pacing have demonstrated that T-wave alternans is a marker of vulnerability to ventricular arrhythmias. Using a spectral analysis technique incorporating noise reduction signal-processing software, we evaluated electrical alternans at rest and with the heart rate elevated during a bicycle exercise protocol. In this study we defined optimal criteria for electrical alternans to separate patients from those without inducible arrhythmias. Alternans and signal-averaged electrocardiographic results were compared with the results of vulnerability to ventricular arrhythmias as defined by induction of sustained ventricular tachycardia or fibrillation at electrophysiologic evaluation. In 27 patients alternans recorded at rest and with exercise had a sensitivity of 89%, specificity of 75%, and overall clinical accuracy of 80% (p <0.003). In this patient population the signal-averaged electrocardiogram was not a significant predictor of arrhythmia vulnerability. This is the first study to report that repolarization alternans can be detected with heart rate elevated with a bicycle exercise protocol. Alternans measured using this technique is an accurate predictor of arrhythmia inducibility.

Effects of radiofrequency catheter ablation on left ventricular structure and function in patients with atrial fibrillation: a meta-analysis.

PubMed

Zhu, Pengju; Zhang, Yong; Jiang, Peiqing; Wang, Zhongsu; Wang, Jiangrong; Yin, Xiangcui; Hou, Yinglong

2014-08-01

Radiofrequency catheter ablation (RFCA) is an effective therapy for atrial fibrillation (AF). This study was designed to investigate the effects of RFCA on left ventricular (LV) structure and function in AF patients. A systematic literature search in MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials was performed to identify trials involving changes of LV structure and function in AF patients undergoing RFCA. Effect size was expressed as weighted mean difference (WMD) with 95% confidence interval (CI). LV end-diastolic diameter (LVEDD), LV end-systolic diameter (LVESD), LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were estimated. A total of 21 trials including 1,135 participants were qualified for this meta-analysis. Compared to the baseline values, there were significant decreases in LVEDV (WMD, -6.39 ml; 95%CI, -12.46 to -0.33) and LVESV (WMD, -6.39 ml; 95%CI, -11.35 to -1.42) and a significant improvement in LVEF (WMD, 6.23%; 95%CI, 3.70 to 8.75), but no significant changes were observed in LVEDD (WMD, -0.64 mm; 95%CI, -2.40 to 1.13) and LVESD (WMD, -0.38 mm; 95%CI, -1.32 to 0.56) after RFCA. Subgroup analysis demonstrated that patients with low LVEF (WMD, 11.90%; 95%CI, 9.16 to 14.64) gained more benefits than those with normal LVEF (WMD, 1.56%; 95%CI, 0.38 to 2.74). Besides, patients with chronic AF (WMD, 10.96%; 95%CI, 4.92 to 17.01) improved more than those with paroxysmal AF (WMD, 1.93%; 95%CI, -0.27 to 4.12). RFCA in AF patients could reverse LV structural remodeling and improve LV systolic function, especially in patients with low LVEF and chronic AF.

Novel CPR system that predicts return of spontaneous circulation from amplitude spectral area before electric shock in ventricular fibrillation.

PubMed

Nakagawa, Yoshihide; Amino, Mari; Inokuchi, Sadaki; Hayashi, Satoshi; Wakabayashi, Tsutomu; Noda, Tatsuya

2017-04-01

Amplitude spectral area (AMSA), an index for analysing ventricular fibrillation (VF) waveforms, is thought to predict the return of spontaneous circulation (ROSC) after electric shocks, but its validity is unconfirmed. We developed an equation to predict ROSC, where the change in AMSA (ΔAMSA) is added to AMSA measured immediately before the first shock (AMSA1). We examine the validity of this equation by comparing it with the conventional AMSA1-only equation. We retrospectively investigated 285 VF patients given prehospital electric shocks by emergency medical services. ΔAMSA was calculated by subtracting AMSA1 from last AMSA immediately before the last prehospital electric shock. Multivariate logistic regression analysis was performed using post-shock ROSC as a dependent variable. Analysis data were subjected to receiver operating characteristic curve analysis, goodness-of-fit testing using a likelihood ratio test, and the bootstrap method. AMSA1 (odds ratio (OR) 1.151, 95% confidence interval (CI) 1.086-1.220) and ΔAMSA (OR 1.289, 95% CI 1.156-1.438) were independent factors influencing ROSC induction by electric shock. Area under the curve (AUC) for predicting ROSC was 0.851 for AMSA1-only and 0.891 for AMSA1+ΔAMSA. Compared with the AMSA1-only equation, the AMSA1+ΔAMSA equation had significantly better goodness-of-fit (likelihood ratio test P<0.001) and showed good fit in the bootstrap method. Post-shock ROSC was accurately predicted by adding ΔAMSA to AMSA1. AMSA-based ROSC prediction enables application of electric shock to only those patients with high probability of ROSC, instead of interrupting chest compressions and delivering unnecessary shocks to patients with low probability of ROSC. Copyright © 2017 Elsevier B.V. All rights reserved.

[Prevention of ventricular fibrillation with the aid of protopine in animal experiments].

PubMed

Burtsev, V N; Dormidontov, E N; Saliaev, V N

1978-04-01

The anti-arrhythmic activity of protopin, quinidine and novocainamide infused intravenously as a preventive and relieving measure was studied in acute experiments on rats with calcium chloride and aconitic arrhythmia. In myocardial fibrillation induced by calcium chloride the contents in the rat heart of adrenalin, noradrenaline, dopa and dopamine were studied by spectrofluorimetry before and after the use of protopin. It was established that in the size of its minimum effective doses which arrest or prevent calcium chloride and aconitic arrhythmias in rats protopin is two to three times more potent than quinidine and novocainamide. The mechanism of the anti-arrhythmic effect of protopin in calcium chloride and aconitic arrhythmias is complex and is due to the suppression of the foci of heterotopic stimulation, decrease in excitability of the myocardial cells and normalization of the catecholamine content in the myocardium.

Atrial fibrillation and hyperthyroidism: A literature review.

PubMed

Reddy, Vivek; Taha, Wael; Kundumadam, Shanker; Khan, Mazhar

Atrial fibrillation is the most common arrhythmia worldwide with increasing frequency noted with age. Hyperthyroidism is a well-known cause of atrial fibrillation with a 16%-60% prevalence of atrial fibrillation in patients with known hyperthyroidism Ross et al. (2016). While hyperthyroidism as a causative factor of atrial fibrillation is well established, this literature review aims to answer several questions on this topic including: 1. The relationship of atrial fibrillation to hyperthyroidism 2. Atrial fibrillation as a predictor of hyperthyroidism 3. The pathophysiology of thyrotoxic atrial fibrillation 4. Subclinical hyperthyroidism and the relationship with atrial fibrillation 5. Cardioversion and Catheter ablation of hyperthyroid patients with atrial fibrillation 6. Thrombotic risk of hyperthyroid patients with atrial fibrillation 7. Management of Thyrotoxic Atrial fibrillation 8. Pharmacological rhythm control in patients with hyperthyroidism and atrial fibrillation 9. Treatment of Hyperthyroidism to prevent atrial fibrillation 10. Clinical Implications of Hyperthyroidism and Atrial Fibrillation. Copyright © 2017 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

A servo-controlled canine model of stable severe ischemic left ventricular failure.

PubMed

Wagner, Richard L; Hood, William B; Howland, Peter A

2009-12-01

Reversible left ventricular failure was produced in conscious dogs by compromise of the coronary circulation. In animals with prior left anterior descending coronary artery occlusion, mean left atrial pressure (LAP) was incorporated into an automatic feedback control system used to inflate a balloon cuff on the circumflex (Cfx) coronary artery. The system could produce stable increases in LAP to 15-20 mm Hg. The dominating system transfer function was the ratio of LAP to balloon volume (BV), which was characterized by a fixed delay (5 s), with LAP/BV = (8e(-jomegatau ))/(0.02 + jomega). The system was stabilized by a phase lead network to reduce oscillations of LAP. A total of seven experiments were conducted in three dogs, and testing of inotropic agents was possible in three experiments under stable conditions with the pump off after an hour or more of operation. Problems encountered were 0.003-0.008 Hz oscillations in LAP in three experiments, which could usually be controlled by reducing the system gain. Late stage ventricular fibrillation occurred in all three animals, but defibrillation was easily accomplished after deflating the Cfx balloon. This system produces reversible left ventricular failure solely due to ischemia, thus closely simulating clinical heart failure due to coronary insufficiency.

Synchronous ventricular pacing with direct capture of the atrioventricular conduction system: Functional anatomy, terminology, and challenges.

PubMed

Mulpuru, Siva K; Cha, Yong-Mei; Asirvatham, Samuel J

2016-11-01

Right ventricular apical pacing is associated with an increased incidence of heart failure, atrial fibrillation, and overall mortality. As a result, pacing the ventricles in a manner that closely mimics normal AV conduction with an intact His-Purkinje system has been explored. Recently, the sustainable benefits of selective His-bundle stimulation have been demonstrated and proposed as the preferred method of ventricular stimulation for appropriate patients. Ideally, conduction system pacing should be selective without myocardial capture, overcome distal bundle branch block when present, and not compromise tricuspid valve function. Contemporary literature on conduction system pacing is confusing largely because of inconsistent terminology and, at times, anatomically inaccurate terms used interchangeably for nonsynonymous anatomic sites. In this review, we discuss the functional anatomy of AV conduction access with specific emphasis on terminology, relationship to the membranous septum, tricuspid valve tissue, and proximity to atrial or ventricular myocardium. The potential benefits of each specific site as well as associated unique difficulties with those sites are described. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Initial clinical experience with ambulatory use of an implantable atrial defibrillator for conversion of atrial fibrillation. Metrix Investigators.

PubMed

Daoud, E G; Timmermans, C; Fellows, C; Hoyt, R; Lemery, R; Dawson, K; Ayers, G M

2000-09-19

A recent study has shown that the implantable atrial defibrillator can restore sinus rhythm in patients with recurrent atrial fibrillation when therapy was delivered under physician observation. The objective of this study was to evaluate the safety and efficacy of ambulatory use of the implantable atrial defibrillator. An atrial defibrillator was implanted in 105 patients (75 men; mean age, 59+/-12 years) with recurrent, symptomatic, drug-refractory atrial fibrillation. After successful 3-month testing, patients could transition to ambulatory delivery of shock therapy. Patients completed questionnaires regarding shock therapy discomfort and therapy satisfaction using a 10-point visual-analog scale (1 represented "not at all," 10 represented "extremely") after each treated episode of atrial fibrillation. During a mean follow-up of 11.7 months, 48 of 105 patients satisfied criteria for transition and received therapy for 275 episodes of atrial fibrillation. Overall shock therapy efficacy was 90% with 1.6+/-1.2 shocks delivered per episode (median, 1). Patients rated shock discomfort as 5.2+/-2.4 for successful therapy and 4.2+/-2.2 for unsuccessful therapy (P:>0.05). The satisfaction score was higher for successful versus unsuccessful therapy (3.4+/-3. 3 versus 8.7+/-1.3, P:<0.05). There was no ventricular proarrhythmia observed throughout the course of this study. Ambulatory use of an implantable atrial defibrillator can safely and successfully convert most episodes of atrial fibrillation, often requiring only a single shock. Successful therapy is associated with high satisfaction and only moderate discomfort.

Evaluation of Right Ventricular Systolic Function in Chagas Disease Using Cardiac Magnetic Resonance Imaging.

PubMed

Moreira, Henrique T; Volpe, Gustavo J; Marin-Neto, José A; Ambale-Venkatesh, Bharath; Nwabuo, Chike C; Trad, Henrique S; Romano, Minna M D; Pazin-Filho, Antonio; Maciel, Benedito C; Lima, João A C; Schmidt, André

2017-03-01

Right ventricular (RV) impairment is postulated to be responsible for prominent systemic congestion in Chagas disease. However, occurrence of primary RV dysfunction in Chagas disease remains controversial. We aimed to study RV systolic function in patients with Chagas disease using cardiac magnetic resonance. This cross-sectional study included 158 individuals with chronic Chagas disease who underwent cardiac magnetic resonance. RV systolic dysfunction was defined as reduced RV ejection fraction based on predefined cutoffs accounting for age and sex. Multivariable logistic regression was used to verify the relationship of RV systolic dysfunction with age, sex, functional class, use of medications for heart failure, atrial fibrillation, and left ventricular systolic dysfunction. Mean age was 54±13 years, 51.2% men. RV systolic dysfunction was identified in 58 (37%) individuals. Although usually associated with reduced left ventricular ejection fraction, isolated RV systolic dysfunction was found in 7 (4.4%) patients, 2 of them in early stages of Chagas disease. Presence of RV dysfunction was not significantly different in patients with indeterminate/digestive form of Chagas disease (35.7%) compared with those with Chagas cardiomyopathy (36.8%) ( P =1.000). In chronic Chagas disease, RV systolic dysfunction is more commonly associated with left ventricular systolic dysfunction, although isolated and early RV dysfunction can also be identified. © 2017 American Heart Association, Inc.

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

Impact of Major Pulmonary Resections on Right Ventricular Function: Early Postoperative Changes.

PubMed

Elrakhawy, Hany M; Alassal, Mohamed A; Shaalan, Ayman M; Awad, Ahmed A; Sayed, Sameh; Saffan, Mohammad M

2018-01-15

Right ventricular (RV) dysfunction after pulmonary resection in the early postoperative period is documented by reduced RV ejection fraction and increased RV end-diastolic volume index. Supraventricular arrhythmia, particularly atrial fibrillation, is common after pulmonary resection. RV assessment can be done by non-invasive methods and/or invasive approaches such as right cardiac catheterization. Incorporation of a rapid response thermistor to pulmonary artery catheter permits continuous measurements of cardiac output, right ventricular ejection fraction, and right ventricular end-diastolic volume. It can also be used for right atrial and right ventricular pacing, and for measuring right-sided pressures, including pulmonary capillary wedge pressure. This study included 178 patients who underwent major pulmonary resections, 36 who underwent pneumonectomy assigned as group (I) and 142 who underwent lobectomy assigned as group (II). The study was conducted at the cardiothoracic surgery department of Benha University hospital in Egypt; patients enrolled were operated on from February 2012 to February 2016. A rapid response thermistor pulmonary artery catheter was inserted via the right internal jugular vein. Preoperatively the following was recorded: central venous pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac output, right ventricular ejection fraction and volumes. The same parameters were collected in fixed time intervals after 3 hours, 6 hours, 12 hours, 24 hours, and 48 hours postoperatively. For group (I): There were no statistically significant changes between the preoperative and postoperative records in the central venous pressure and mean arterial pressure; there were no statistically significant changes in the preoperative and 12, 24, and 48 hour postoperative records for cardiac index; 3 and 6 hours postoperative showed significant changes. There were statistically significant changes between the preoperative and

Triple-site pacing for cardiac resynchronization in permanent atrial fibrillation - Acute phase results from a prospective observational study.

PubMed

Marques, Pedro; Nobre Menezes, Miguel; Lima da Silva, Gustavo; Bernardes, Ana; Magalhães, Andreia; Cortez-Dias, Nuno; Carpinteiro, Luís; de Sousa, João; Pinto, Fausto J

2016-06-01

Multi-site pacing is emerging as a new method for improving response to cardiac resynchronization therapy (CRT), but has been little studied, especially in patients with atrial fibrillation. We aimed to assess the effects of triple-site (Tri-V) vs. biventricular (Bi-V) pacing on hemodynamics and QRS duration. This was a prospective observational study of patients with permanent atrial fibrillation and ejection fraction <40% undergoing CRT implantation (n=40). One right ventricular (RV) lead was implanted in the apex and another in the right ventricular outflow tract (RVOT) septal wall. A left ventricular (LV) lead was implanted in a conventional venous epicardial position. Cardiac output (using the FloTrac™ Vigileo™ system), mean QRS and ejection fraction were calculated. Mean cardiac output was 4.81±0.97 l/min with Tri-V, 4.68±0.94 l/min with RVOT septal and LV pacing, and 4.68±0.94 l/min with RV apical and LV pacing (p<0.001 for Tri-V vs. both BiV). Mean pre-implantation QRS was 170±25 ms, 123±18 ms with Tri-V, 141±25 ms with RVOT septal pacing and LV pacing and 145±19 with RV apical and LV pacing (p<0.001 for Tri-V vs. both BiV and pre-implantation). Mean ejection fraction was significantly higher with Tri-V (30±11%) vs. Bi-V pacing (28±12% with RVOT septal and LV pacing and 28±11 with RV apical and LV pacing) and pre-implantation (25±8%). Tri-V pacing produced higher cardiac output and shorter QRS duration than Bi-V pacing. This may have a significant impact on the future of CRT. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

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

Juvenile Idiopathic Arthritis

MedlinePlus

... Is Juvenile Idiopathic Arthritis the same as Juvenile Rheumatoid Arthritis? Yes, Juvenile Idiopathic Arthritis (JIA) is a new ... of chronic inflammatory diseases that affect children. Juvenile Rheumatoid Arthritis (JRA) is the older term that was used ...

Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)

MedlinePlus

... Asked Questions Español Condiciones Chinese Conditions Idiopathic Intracranial Hypertension (Pseudotumor Cerebri) En Español Read in Chinese What is idiopathic intracranial hypertension? Idiopathic intracranial hypertension (IIH) is a disorder that ...

Adverse effects of permanent atrial fibrillation on heart failure in patients with preserved left ventricular function and chronic right apical pacing for complete heart block.

PubMed

Lampe, Brigitte; Hammerstingl, Christoph; Schwab, Jörg Otto; Mellert, Fritz; Stoffel-Wagner, Birgit; Grigull, Andreas; Fimmers, Rolf; Maisch, Bernhard; Nickenig, Georg; Lewalter, Thorsten; Yang, Alexander

2012-10-01

The impact of atrial fibrillation (AF) on heart failure (HF) was evaluated in patients with preserved left ventricular (LV) function and long-term right ventricular (RV) pacing for complete heart block. Clinical, echocardiographic, and laboratory parameters of HF were assessed in 35 patients with established AF who had undergone ablation of the atrioventricular node and pacemaker implantation (Group A) and 31 patients who received dual-chamber pacing for spontaneous complete heart block (Group B). During a follow-up period of 12.7 ± 7.5 years, New York Heart Association (NYHA) functional class increased from 1.3 ± 0.5 to 2.1 ± 0.6 (p < 0.0001) in Group A, and from 1.3 ± 0.4 to 1.6 ± 0.7 (p < 0.01) in Group B. Left ventricular ejection fraction (LVEF) decreased from 59.7 ± 5.1 to 53.0 ± 8.2 (p < 0.0001) in Group A, but remained stable (58.6 ± 4.2 vs. 56.9 ± 7.0 %, p = 0,21) in Group B. At the end of follow-up, markers of LV function were moderately depressed in Group A compared with those in Group B: NYHA class 2.1 ± 0.6 versus 1.6 ± 0.7, p = 0.001; LVEF 53.0 ± 8.2 versus 56.9 ± 7.0 %, p < 0.05; LV diastolic diameter 53.6 ± 5.8 mm versus 50.7 ± 4.9 mm, p < 0.05; N-terminal pro-brain natriuretic peptide (NT-proBNP) 1116.8 ± 883.9 versus 622.9 ± 1059.4 pg/ml, p < 0.05. Progression of paroxysmal AF to permanent AF during follow-up was common, while new onset of AF was rare. Permanent AF was an independent predictor of declining LVEF >10 %, increasing NYHA class ≥1, and NT-proBNP levels >1,000 pg/ml. Permanent AF was associated with adverse effects on LV function and symptoms of HF in patients with long-term RV pacing for complete heart block, and appears to play an important role in the development of HF in this specific patient cohort.

Juvenile idiopathic arthritis.

PubMed

Boros, Christina; Whitehead, Ben

2010-09-01

Juvenile idiopathic arthritis is the most common rheumatic disease in childhood, occurring in approximately 1:500 children. Despite a recent expansion in treatment options and improvement of outcomes, significant morbidity still occurs. This article outlines the clinical manifestations, assessment, detection of complications, treatment options and monitoring requirements, with the aid of guidelines recently published by The Royal Australian College of General Practitioners, which provide practical support for general practitioners to ensure best practice care and to prevent lifelong disability in patients with juvenile idiopathic arthritis. General practice plays an important role in the early detection, initial management and ongoing monitoring of children with juvenile idiopathic arthritis. Early detection involves understanding the classification framework for subtypes of juvenile idiopathic arthritis, and being aware of the clinical manifestations and how to look for them, through history, examination and appropriate investigation. The major extra-articular manifestations of juvenile idiopathic arthritis are uveitis and growth disturbance. Treatment options include nonsteroidal anti-inflammatory drugs, methotrexate, biologic agents, and corticosteroids. Management using a multidisciplinary approach can prevent long term sequelae. Unfortunately, approximately 50% of children will have active disease as adults.

Magnetic versus manual catheter navigation for mapping and ablation of right ventricular outflow tract ventricular arrhythmias: a randomized controlled study.

PubMed

Zhang, Fengxiang; Yang, Bing; Chen, Hongwu; Ju, Weizhu; Kojodjojo, Pipin; Cao, Kejiang; Chen, Minglong

2013-08-01

No randomized controlled study has prospectively compared the performance and clinical outcomes of remote magnetic control (RMC) vs manual catheter control (MCC) during ablation of right ventricular outflow tract (RVOT) ventricular premature complexes (VPC) or ventricular tachycardia (VT). The purpose of this study was to prospectively evaluate the efficacy and safety of using either RMC vs MCC for mapping and ablation of RVOT VPC/VT. Thirty consecutive patients with idiopathic RVOT VPC/VT were referred for catheter ablation and randomized into either the RMC or MCC group. A noncontact mapping system was deployed in the RVOT to identify origins of VPC/VT. Conventional activation and pace-mapping was performed to guide ablation. If ablation performed using 1 mode of catheter control was acutely unsuccessful, the patient crossed over to the other group. The primary endpoints were patients' and physicians' fluoroscopic exposure and times. Mean procedural times were similar between RMC and MCC groups. The fluoroscopic exposure and times for both patients and physicians were much lower in the RMC group than in the MCC group. Ablation was acutely successful in 14 of 15 patients in the MCC group and 10 of 15 in the RMC group. Following crossover, acute success was achieved in all patients. No major complications occurred in either group. During 22 months of follow-up, RVOT VPC recurred in 2 RMC patients. RMC navigation significantly reduces patients' and physicians' fluoroscopic times by 50.5% and 68.6%, respectively, when used in conjunction with a noncontact mapping system to guide ablation of RVOT VPC/VT. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Sick sinus syndrome with HCN4 mutations shows early onset and frequent association with atrial fibrillation and left ventricular noncompaction.

PubMed

Ishikawa, Taisuke; Ohno, Seiko; Murakami, Takashi; Yoshida, Kentaro; Mishima, Hiroyuki; Fukuoka, Tetsuya; Kimoto, Hiroki; Sakamoto, Risa; Ohkusa, Takafumi; Aiba, Takeshi; Nogami, Akihiko; Sumitomo, Naokata; Shimizu, Wataru; Yoshiura, Koh-Ichiro; Horigome, Hitoshi; Horie, Minoru; Makita, Naomasa

2017-05-01

Familial sick sinus syndrome (SSS) is often attributable to mutations in genes encoding the cardiac Na channel SCN5A and pacemaker channel HCN4. We previously found that SSS with SCN5A mutations shows early onset of manifestations and male predominance. Despite recent reports on the complications of atrial fibrillation (AF) and left ventricular noncompaction (LVNC) in patients with SSS caused by HCN4 mutations, their overall clinical spectrum remains unknown. The purpose of this study was to investigate the clinical and demographic features of SSS patients carrying HCN4 mutations. We genetically screened 38 unrelated SSS families and functionally analyzed the mutant SCN5A and HCN4 channels by patch clamping. We also evaluated the clinical features of familial SSS by a meta-analysis of 48 SSS probands with mutations in HCN4 (n = 16) and SCN5A (n = 32), including previously reported cases, and 538 sporadic SSS cases. We identified two HCN4 and three SCN5A loss-of-function mutations in our familial SSS cohort. Meta-analysis of HCN4 mutation carriers showed a significantly younger age at diagnosis (39.1 ± 21.7 years) than in sporadic SSS (74.3 ± 0.4 years; P <.001), but a significantly older age than in SCN5A mutation carriers (20.0 ± 17.6 years; P = .003). Moreover, HCN4 mutation carriers were more frequently associated with AF (43.8%) and LVNC (50%) and with older age at pacemaker implantation (43.5 ± 22.1 years) than were SCN5A mutation carriers (17.8 ± 16.5 years; P <.001). SSS with HCN4 mutations may form a distinct SSS subgroup characterized by early clinical manifestation after adolescence and frequent association with AF and LVNC. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Ventricular fibrillation

MedlinePlus

... arrives. VF is treated by delivering a quick electric shock through the chest. It is done using a device called an external defibrillator. The electric shock can immediately restore the heartbeat to a ...

Ventricular Fibrillation

MedlinePlus

... heart with a device called an automated external defibrillator (AED). Treatments to prevent sudden cardiac death for ... can even be purchased for your home. Portable defibrillators come with built-in instructions for their use. ...

Effect of Omega-3 Polyunsaturated Fatty Acid Supplementation in Patients with Atrial Fibrillation.

PubMed

Kumar, Sanjay; Qu, Sarah; Kassotis, John T

2012-01-01

Atrial fibrillation (AF) is the most common sustained atrial arrhythmia conferring a higher morbidity and mortality. Despite the increasing incidence of AF; available therapies are far from perfect. Dietary fish oils, containing omega 3 fatty acids, also called polyunsaturated fatty acid [PUFA] have demonstrated beneficial electrophysiological, autonomic and anti-inflammatory effects on both atrial and ventricular tissue. Multiple clinical trials, focusing on various subsets of patients with AF, have studied the role of PUFA and their potential role in reducing the incidence of this common arrhythmia. While PUFA appears to have a beneficial effect in the primary prevention of AF in the elderly with structural heart disease, this benefit has not been universally observed. In the secondary prevention of AF, PUFA seems to have a greater impact in the reducing AF in patients with paroxysmal or persistent AF, stages of AF associated with less atrial fibrosis and negative structural remodeling. However, AF suppression has not been consistently demonstrated in clinical trials. In patients undergoing heart surgery, increasing PUFA intake has yielded mixed results in terms of AF prevention post-operatively; however, increased PUFA has been associated with a reduction in hospital stay. Therefore recommending the use of PUFA for the purpose of AF reduction remains controversial. This is in part attributable to the complexity of AF. Other conflicting variables include: heterogeneous patient populations studied; variable dosing; duration of follow-up; comorbidities; and, concomitant pharmacotherapy. This review article reviews in detail available basic and clinical research studies of fish oil in the treatment of AF, and its role in the treatment of this common disorder. AF=Atrial fibrillation, CHS=Cardiovascular Health Study,CABG=Coronary artery bypass surgery, d=Day, DHA=Docosahexaenoic acid, EPA=Eicosapentaenoic acid, ERP= Effective refractory period, g=Gram, PAF= Paroxysmal

Highly sensitive single-fibril erosion assay demonstrates mechanochemical switch in native collagen fibrils

PubMed Central

Flynn, Brendan P.; Tilburey, Graham E.

2013-01-01

It has been established that the enzyme susceptibility of collagen, the predominant load-bearing protein in vertebrates, is altered by applied tension. However, whether tensile force increases or decreases the susceptibility to enzyme is a matter of contention. It is critical to establish a definitive understanding of the direction and magnitude of the force versus catalysis rate (kC) relationship if we are to properly interpret connective tissue development, growth, remodeling, repair, and degeneration. In this investigation, we examine collagen/enzyme mechanochemistry at the smallest scale structurally relevant to connective tissue: the native collagen fibril. A single-fibril mechanochemical erosion assay with nN force resolution was developed which permits detection of the loss of a few layers of monomer from the fibril surface. Native type I fibrils (bovine) held at three levels of tension were exposed to Clostridium histolyticum collagenase A. Fibrils held at zero-load failed rapidly and consistently (20 min) while fibrils at 1.8 pN/monomer failed more slowly (35–55 min). Strikingly, fibrils at 23.9 pN/monomer did not exhibit detectable degradation. The extracted force versus kC data were combined with previous single-molecule results to produce a “master curve” which suggests that collagen degradation is governed by an extremely sensitive mechanochemical switch. PMID:22584606

Vocal cord paralysis: What matters between idiopathic and non-idiopathic cases?

PubMed

Özbal Koç, Ayça Eltaf; Türkoğlu, Seda Babakurban; Erol, Ozan; Erbek, Selim

2016-01-01

This study aims to evaluate the demographic and clinical characteristics of patients with idiopathic and non-idiopathic vocal cord paralysis (VCP). This retrospective cohort was performed on data extracted from medical files of 92 consecutive patients (43 males, 49 females; median age 52.1±23.1 years; min. 1 - max. 87) with VCP diagnosed in the otorhinolaryngology department between April 2012 and December 2015. Diagnoses associated with VCP, side of involvement (right, left or bilateral) and previous medical histories were noted and compared between patients with idiopathic and non-idiopathic VCP. Vocal cord paralysis occurred on the left side (n=56, 60.9%), right side (n=28, 30.4%) or bilaterally (n=8, 8.7%). A clinical entity related with VCP was identified in 63 patients (68.5%), while 29 (31.5%) patients had idiopathic VCP. Most common etiologies for VCP were thyroid surgery (n=32, 34.8%), cardiovascular surgery (n=9, 9.8%), lung cancer (n=6, 6.5%) and cardiac anomalies (n=4, 4.3%), respectively. Patients with idiopathic VCP were significantly older (p<0.001), while gender distribution (p=0.121) and side of involvement (p=0.340) did not differ between two groups. Vocal cord paralysis is a relatively common clinical entity with substantial rate of morbidity. Identification of the underlying etiology and awareness on the clinical characteristics are keystones for foreseeing complications and determining the appropriate therapeutic modality.

d,l-Sotalol reverses abbreviated atrial refractoriness and prevents promotion of atrial fibrillation in a canine model with left ventricular dysfunction induced by atrial tachypacing.

PubMed

Sakamoto, Tamotsu; Fujiki, Akira; Nakatani, Yosuke; Sakabe, Masao; Mizumaki, Koichi; Hashimoto, Norio; Inoue, Hiroshi

2009-10-01

This study evaluated antiarrhythmic effects of d,l-sotalol in a canine atrial fibrillation (AF) model with left ventricular dysfunction. Thirteen beagles (Sotalol group n=7 and Control group n=6) were subjected to atrial tachypacing (ATP) (400 beats/min) with intact atrioventricular conduction for 4 weeks. Oral d,l-sotalol (2 mg/kg) was administered 1 week after starting ATP and continued throughout the experiment. One week after starting ATP, atrial effective refractory periods (AERPs) were shortened in both groups. However, d,l-sotalol treatment gradually prolonged AERP, resulting in a significant prolongation of AERP compared with the Control group at 4 weeks (Control 76 +/-4 and Sotalol 126 +/-5 ms, p<0.01). d,l-Sotalol treatment showed lower AF inducibility and shorter AF duration at 4 weeks. In the control group, expressions of L-type Ca(2+) channel alpha1c and Kv4.3 mRNA were downregulated by 46.2% and 43.0%, respectively, after 4 weeks of ATP; d,l-sotalol treatment did not affect these changes. d,l-Sotalol treatment prolonged AERP, even after atrial electrical remodeling had developed, and prevented AF perpetuation without affecting downregulated expression of L-type Ca(2+) channel alpha1c and Kv4.3 mRNA in an ATP-induced canine AF model.

Idiopathic normal-pressure hydrocephalus: temporal changes in ADC during cardiac cycle.

PubMed

Ohno, Naoki; Miyati, Tosiaki; Mase, Mitsuhito; Osawa, Tomoshi; Kan, Hirohito; Kasai, Harumasa; Hara, Masaki; Shibamoto, Yuta; Hayashi, Norio; Gabata, Toshifumi; Matsui, Osamu

2011-11-01

To determine whether temporal changes in apparent diffusion coefficient (ADC) over the cardiac cycle are different in patients with idiopathic normal-pressure hydrocephalus (INPH) as compared with patients with ex vacuo ventricular dilatation and healthy control subjects. This prospective study was approved by the institutional review board and was performed only after informed consent was obtained from each patient. At 1.5 T, electrocardiographically triggered single-shot diffusion echo-planar magnetic resonance imaging (b = 0 and 1000 sec/mm(2)) was performed with sensitivity encoding and half-scan techniques to minimize bulk motion. ΔADC was defined as the difference between maximum and minimum ADC on a pixel-by-pixel basis over 20 phases of the cardiac cycle. Mean ADC during the diastolic phase and ΔADC in the frontal white matter were determined in patients with INPH (n = 13), patients with ex vacuo ventricular dilatation (n = 8), and healthy volunteers (n = 10). Kruskal-Wallis tests were used to determine significance between groups. Mean ΔADC in the INPH group was significantly higher than that in the ex vacuo ventricular dilatation and control groups (P < .01 for both). There was no significant difference in ΔADC between the ex vacuo ventricular dilatation and control groups (P = .86). There was no significant difference in mean ADC during the diastolic phase among groups (P > .05 for all). There was no significant correlation between ΔADC and mean ADC during the diastolic phase in any group. Determination of fluctuation of ADC over the cardiac cycle may render it possible to noninvasively obtain new and more detailed information than that provided by standard ADC measurement in suspected INPH, potentially facilitating the diagnosis of this disease. RSNA, 2011

Effect of right ventricular pacing lead site on left ventricular function in patients with high-grade atrioventricular block: results of the Protect-Pace study.

PubMed

Kaye, Gerald C; Linker, Nicholas J; Marwick, Thomas H; Pollock, Lucy; Graham, Laura; Pouliot, Erika; Poloniecki, Jan; Gammage, Michael

2015-04-07

Chronic right ventricle (RV) apical (RVA) pacing is standard treatment for an atrioventricular (AV) block but may be deleterious to left ventricle (LV) systolic function. Previous clinical studies of non-apical pacing have produced conflicting results. The aim of this randomized, prospective, international, multicentre trial was to compare change in LV ejection fraction (LVEF) between right ventricular apical and high septal (RVHS) pacing over a 2-year study period. We randomized 240 patients (age 74 ± 11 years, 67% male) with a high-grade AV block requiring >90% ventricular pacing and preserved baseline LVEF >50%, to receive pacing at the RVA (n = 120) or RVHS (n = 120). At 2 years, LVEF decreased in both the RVA (57 ± 9 to 55 ± 9%, P = 0.047) and the RVHS groups (56 ± 10 to 54 ± 10%, P = 0.0003). However, there was no significant difference in intra-patient change in LVEF between confirmed RVA (n = 85) and RVHS (n = 83) lead position (P = 0.43). There were no significant differences in heart failure hospitalization, mortality, the burden of atrial fibrillation, or plasma brain natriutetic peptide levels between the two groups. A significantly greater time was required to place the lead in the RVHS position (70 ± 25 vs. 56 ± 24 min, P < 0.0001) with longer fluoroscopy times (11 ± 7 vs. 5 ± 4 min, P < 0.0001). In patients with a high-grade AV block and preserved LV function requiring a high percentage of ventricular pacing, RVHS pacing does not provide a protective effect on left ventricular function over RVA pacing in the first 2 years. ClinicalTrials.gov number NCT00461734. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Idiopathic hypersomnia.

PubMed

Billiard, Michel; Sonka, Karel

2016-10-01

Idiopathic hypersomnia continues to evolve from the concept of "sleep drunkenness" introduced by Bedrich Roth in Prague in 1956 and the description of idiopathic hypersomnia with two forms, polysymptomatic and monosymptomatic, by the same Bedrich Roth in 1976. The diagnostic criteria of idiopathic hypersomnia have varied with the successive revisions of the International classifications of sleep disorders, including the recent 3rd edition. No epidemiological studies have been conducted so far. Disease onset occurs most often during adolescence or young adulthood. A familial background is often present but rigorous studies are still lacking. The key manifestation is hypersomnolence. It is often accompanied by sleep of long duration and debilitating sleep inertia. Polysomnography (PSG) followed by a multiple sleep latency test (MSLT) is mandatory, as well as a 24 h PSG or a 2-wk actigraphy in association with a sleep log to ensure a total 24-h sleep time longer than or equal to 66O minutes, when the mean sleep latency on the MSLT is longer than 8 min. Yet, MSLT is neither sensitive nor specific and the polysomnographic diagnostic criteria require continuous readjustment and biologic markers are still lacking. Idiopathic hypersomnia is most often a chronic condition though spontaneous remission may occur. The condition is disabling, sometimes even more so than narcolepsy type 1 or 2. Based on neurochemical, genetic and immunological analyses as well as on exploration of the homeostatic and circadian processes of sleep, various pathophysiological hypotheses have been proposed. Differential diagnosis involves a number of diseases and it is not yet clear whether idiopathic hypersomnia and narcolepsy type 2 are not the same condition. Until now, the treatment of idiopathic hypersomnia has mirrored that of the sleepiness of narcolepsy type 1 or 2. The first randomized, double-blind, placebo-controlled trials of modafinil have just been published, as well as a double

Nanomechanical properties of single amyloid fibrils

NASA Astrophysics Data System (ADS)

Sweers, K. K. M.; Bennink, M. L.; Subramaniam, V.

2012-06-01

Amyloid fibrils are traditionally associated with neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease or Creutzfeldt-Jakob disease. However, the ability to form amyloid fibrils appears to be a more generic property of proteins. While disease-related, or pathological, amyloid fibrils are relevant for understanding the pathology and course of the disease, functional amyloids are involved, for example, in the exceptionally strong adhesive properties of natural adhesives. Amyloid fibrils are thus becoming increasingly interesting as versatile nanobiomaterials for applications in biotechnology. In the last decade a number of studies have reported on the intriguing mechanical characteristics of amyloid fibrils. In most of these studies atomic force microscopy (AFM) and atomic force spectroscopy play a central role. AFM techniques make it possible to probe, at nanometer length scales, and with exquisite control over the applied forces, biological samples in different environmental conditions. In this review we describe the different AFM techniques used for probing mechanical properties of single amyloid fibrils on the nanoscale. An overview is given of the existing mechanical studies on amyloid. We discuss the difficulties encountered with respect to the small fibril sizes and polymorphic behavior of amyloid fibrils. In particular, the different conformational packing of monomers within the fibrils leads to a heterogeneity in mechanical properties. We conclude with a brief outlook on how our knowledge of these mechanical properties of the amyloid fibrils can be exploited in the construction of nanomaterials from amyloid fibrils.

Pulmonary Hypertension due to Radiofrequency Catheter Ablation (RFCA) for Atrial Fibrillation: The Lungs, the Atrium or the Ventricle?

PubMed

Verma, Isha; Tripathi, Hemantkumar; Sikachi, Rutuja Rajanikant; Agrawal, Abhinav

2016-12-01

Atrial fibrillation is the most common heart rhythm disorder in United States, characterised by rapid and irregular beating of both the atria resulting in the similar ventricular response. While rate and rhythm control using pharmacological regimens remain the primary management strategies in these patients, radiofrequency catheter ablation (RFCA) is rapidly rising as an alternative modality of treatment. Increase in the incidence of RFCA has shed light on complications associated with this procedure. Pulmonary hypertension (PH) is one of the long-term complications that has been observed postcatheter ablation. There have been multiple mechanisms which have been proposed to explain these elevated pulmonary pressures. These include the involvement of the lungs due to pulmonary vein stenosis, pulmonary vein occlusion and, rarely, pulmonary embolism. Radiofrequency catheter ablation can also lead to scarring of the atrium which can cause left atrial diastolic dysfunction leading to elevated pulmonary pressures. Recently, it was also proposed that elevated pulmonary pressure was related to the unmasking of left ventricular diastolic dysfunction occurring after this procedure. In this article, we review all the mechanisms that are associated with the development of pulmonary hypertension in patients undergoing RCFA for atrial fibrillation and the approach to diagnosis and management of such patients. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Left ventricular ejection fraction and left atrium diameter related to new-onset atrial fibrillation following acute myocardial infarction: a systematic review and meta-analysis.

PubMed

Zeng, Rui-Xiang; Chen, Mao-Sheng; Lian, Bao-Tao; Liao, Peng-Da; Zhang, Min-Zhou

2017-10-06

New-onset atrial fibrillation (NOAF) occurs frequently in patients with acute myocardial infarction (AMI), and is associated with increased subsequent cardiovascular mortality. However, only a few studies directly evaluated the relationship of left ventricular ejection fraction (LVEF) or left atrium diameter (LAD) and NOAF following AMI. MEDLINE ® , EMBASE ® and the Cochrane Library were carried out to find studies until January 2017. Pooled mean difference (MD) and 95% confidence interval (CI) were calculated to evaluate the value of LVEF and LAD in the prediction of NOAF after AMI. We performed sensitivity analyses to explore the potential sources of heterogeneity. Statistical analyses were carried out using the Revman 5.3. We included 10 qualifying studies comprising a total of 708 patients with NOAF and 6785 controls. Overall, decreased LVEF and increased LAD levels had a significant positive association with NOAF in patients with AMI. The MD in the LVEF levels between the patients with and those without NOAF was -4.91 units (95% Cl: -5.70 to -4.12), test for overall effect z-score = 12.18 ( p < 0.00001, I 2 = 35%). Moreover, in a subgroup analysis, the MD for LAD and NOAF was 2.55 units (95% Cl: 1.91 to 3.19), test for overall effect z-score = 7.80 ( p < 0.00001, I 2 = 57%). Our meta-analysis demonstrated that both decreased LVEF and increased LAD levels were associated with greater risk of NOAF following AMI.

Toward understanding insulin fibrillation.

PubMed

Brange, J; Andersen, L; Laursen, E D; Meyn, G; Rasmussen, E

1997-05-01

Formation of insulin fibrils is a physical process by which partially unfolded insulin molecules interact with each other to form linear aggregates. Shielding of hydrophobic domains is the main driving force for this process, but formation of intermolecular beta-sheet may further stabilize the fibrillar structure. Conformational displacement of the B-chain C-terminal with exposure of nonpolar, aliphatic core residues, including A2, A3, B11, and B15, plays a crucial role in the fibrillation process. Recent crystal analyses and molecular modeling studies have suggested that when insulin fibrillates this exposed domain interacts with a hydrophobic surface domain formed by the aliphatic residues A13, B6, B14, B17, and B18, normally buried when three insulin dimers form a hexamer. In rabbit immunization experiments, insulin fibrils did not elicit an increased immune response with respect to formation of IgG insulin antibodies when compared with native insulin. In contrast, the IgE response increased with increasing content of insulin in fibrillar form. Strategies and practical approaches to prevent insulin from forming fibrils are reviewed. Stabilization of the insulin hexameric structure and blockage of hydrophobic interfaces by addition of surfactants are the most effective means of counteracting insulin fibrillation.

Timing of myocardial trpm7 deletion during cardiogenesis variably disrupts adult ventricular function, conduction, and repolarization.

PubMed

Sah, Rajan; Mesirca, Pietro; Mason, Xenos; Gibson, William; Bates-Withers, Christopher; Van den Boogert, Marjolein; Chaudhuri, Dipayan; Pu, William T; Mangoni, Matteo E; Clapham, David E

2013-07-09

Transient receptor potential (TRP) channels are a superfamily of broadly expressed ion channels with diverse physiological roles. TRPC1, TRPC3, and TRPC6 are believed to contribute to cardiac hypertrophy in mouse models. Human mutations in TRPM4 have been linked to progressive familial heart block. TRPM7 is a divalent-permeant channel and kinase of unknown function, recently implicated in the pathogenesis of atrial fibrillation; however, its function in ventricular myocardium remains unexplored. We generated multiple cardiac-targeted knockout mice to test the hypothesis that TRPM7 is required for normal ventricular function. Early cardiac Trpm7 deletion (before embryonic day 9; TnT/Isl1-Cre) results in congestive heart failure and death by embryonic day 11.5 as a result of hypoproliferation of the compact myocardium. Remarkably, Trpm7 deletion late in cardiogenesis (about embryonic day 13; αMHC-Cre) produces viable mice with normal adult ventricular size, function, and myocardial transcriptional profile. Trpm7 deletion at an intermediate time point results in 50% of mice developing cardiomyopathy associated with heart block, impaired repolarization, and ventricular arrhythmias. Microarray analysis reveals elevations in transcripts of hypertrophy/remodeling genes and reductions in genes important for suppressing hypertrophy (Hdac9) and for ventricular repolarization (Kcnd2) and conduction (Hcn4). These transcriptional changes are accompanied by action potential prolongation and reductions in transient outward current (Ito; Kcnd2). Similarly, the pacemaker current (If; Hcn4) is suppressed in atrioventricular nodal cells, accounting for the observed heart block. Trpm7 is dispensable in adult ventricular myocardium under basal conditions but is critical for myocardial proliferation during early cardiogenesis. Loss of Trpm7 at an intermediate developmental time point alters the myocardial transcriptional profile in adulthood, impairing ventricular function, conduction

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

Right ventricular dysfunction affects survival after surgical left ventricular restoration.

PubMed

Couperus, Lotte E; Delgado, Victoria; Palmen, Meindert; van Vessem, Marieke E; Braun, Jerry; Fiocco, Marta; Tops, Laurens F; Verwey, Harriëtte F; Klautz, Robert J M; Schalij, Martin J; Beeres, Saskia L M A

2017-04-01

Several clinical and left ventricular parameters have been associated with prognosis after surgical left ventricular restoration in patients with ischemic heart failure. The aim of this study was to determine the prognostic value of right ventricular function. A total of 139 patients with ischemic heart failure (62 ± 10 years; 79% were male; left ventricular ejection fraction 27% ± 7%) underwent surgical left ventricular restoration. Biventricular function was assessed with echocardiography before surgery. The independent association between all-cause mortality and right ventricular fractional area change, tricuspid annular plane systolic excursion, and right ventricular longitudinal peak systolic strain was assessed. The additive effect of multiple impaired right ventricular parameters on mortality also was assessed. Baseline right ventricular fractional area change was 42% ± 9%, tricuspid annular plane systolic excursion was 18 ± 3 mm, and right ventricular longitudinal peak systolic strain was -24% ± 7%. Within 30 days after surgery, 15 patients died. Right ventricular fractional area change (hazard ratio, 0.93; 95% confidence interval, 0.88-0.98; P < .01), tricuspid annular plane systolic excursion (hazard ratio, 0.80; 95% confidence interval, 0.66-0.96; P = .02), and right ventricular longitudinal peak systolic strain (hazard ratio, 1.15; 95% confidence interval, 1.05-1.26; P < .01) were independently associated with 30-day mortality, after adjusting for left ventricular ejection fraction and aortic crossclamping time. Right ventricular function was impaired in 21%, 20%, and 27% of patients on the basis of right ventricular fractional area change, tricuspid annular plane systolic excursion, and right ventricular longitudinal peak systolic strain, respectively. Any echocardiographic parameter of right ventricular dysfunction was present in 39% of patients. The coexistence of several impaired right ventricular parameters per patient was

Effects of Late Sodium Current Blockade on Ventricular Refibrillation in a Rabbit Model.

PubMed

Azam, Mohammed Ali; Zamiri, Nima; Massé, Stéphane; Kusha, Marjan; Lai, Patrick F H; Nair, Govind K; Tan, Nigel S; Labos, Christopher; Nanthakumar, Kumaraswamy

2017-03-01

After defibrillation of initial ventricular fibrillation (VF), it is crucial to prevent refibrillation to ensure successful resuscitation outcomes. Inability of the late Na + current to inactivate leads to intracellular Ca 2+ dysregulation and arrhythmias. Our aim was to determine the effects of ranolazine and GS-967, inhibitors of the late Na + current, on ventricular refibrillation. Long-duration VF was induced electrically in Langendorff-perfused rabbit hearts (n=22) and terminated with a defibrillator after 6 minutes. Fibrillating hearts were randomized into 3 groups: treatment with ranolazine, GS-967, or nontreated controls. In the treated groups, hearts were perfused with ranolazine or GS-967 at 2 minutes of VF. In control experiments, perfusion solution was supplemented with isotonic saline in lieu of a drug. Inducibility of refibrillation was assessed after initial long-duration VF by attempting to reinduce VF. Sustained refibrillation was successful in fewer ranolazine-treated (29.17%; P =0.005) or GS-967-treated (45.83%, P =0.035) hearts compared with that in nontreated control hearts (84.85%). In GS-967-treated hearts, significantly more spontaneous termination of initial long-duration VF was observed (66.67%; P =0.01). Ca 2+ transient duration was reduced in ranolazine-treated hearts compared with that in controls ( P =0.05) and also Ca 2+ alternans ( P =0.03). Late Na + current inhibition during long-duration VF reduces the susceptibility to subsequent refibrillation, partially by mitigating dysregulation of intracellular Ca 2+ . These results suggest the potential therapeutic use of ranolazine and GS-967 and call for further testing in cardiac arrest models. © 2017 American Heart Association, Inc.

Long-term survival after ablation of the atrioventricular node and implantation of a permanent pacemaker in patients with atrial fibrillation.

PubMed

Ozcan, C; Jahangir, A; Friedman, P A; Patel, P J; Munger, T M; Rea, R F; Lloyd, M A; Packer, D L; Hodge, D O; Gersh, B J; Hammill, S C; Shen, W K

2001-04-05

In patients with atrial fibrillation that is refractory to drug therapy, radio-frequency ablation of the atrioventricular node and implantation of a permanent pacemaker are an alternative therapeutic approach. The effect of this procedure on long-term survival is unknown. We studied all patients who underwent ablation of the atrioventricular node and implantation of a permanent pacemaker at the Mayo Clinic between 1990 and 1998. Observed survival was compared with the survival rates in two control populations: age- and sex-matched members of the Minnesota population between 1970 and 1990 and consecutive patients with atrial fibrillation who received drug therapy in 1993. A total of 350 patients (mean [+/-SD] age, 68+/-11 years) were studied. During a mean of 36+/-26 months of follow-up, 78 patients died. The observed survival rate was significantly lower than the expected survival rate based on the general Minnesota population (P<0.001). Previous myocardial infarction (P<0.001), a history of congestive heart failure (P=0.02), and treatment with cardiac drugs after ablation (P=0.03) were independent predictors of death. Observed survival among patients without these three risk factors was similar to expected survival (P=0.43). None of the 26 patients with lone atrial fibrillation died during follow-up (37+/-27 months). The observed survival rate among patients who underwent ablation was similar to that among 229 controls with atrial fibrillation (mean age, 67+/-12 years) who received drug therapy (P=0.44). In the absence of underlying heart disease, survival among patients with atrial fibrillation after ablation of the atrioventricular node is similar to expected survival in the general population. Long-term survival is similar for patients with atrial fibrillation, whether they receive ablation or drug therapy. Control of the ventricular rate by ablation of the atrioventricular node and permanent pacing does not adversely affect long-term survival.

The Role of Apamin Sensitive Calcium Activated Small Conductance Potassium Currents on the Mechanisms of Ventricular Fibrillation in Pacing Induced Failing Rabbit Hearts

PubMed Central

Yin, Dechun; Hsieh, Yu-Cheng; Tsai, Wei-Chung; Wu, Adonis Zhi-Yang; Jiang, Zhaolei; Chan, Yi-Hsin; Xu, Dongzhu; Yang, Na; Shen, Changyu; Chen, Zhenhui; Lin, Shien-Fong; Chen, Peng-Sheng; Everett, Thomas H.

2017-01-01

Background Ventricular fibrillation (VF) during heart failure is characterized by stable reentrant spiral waves (rotors). Apamin-sensitive small conductance calcium activated potassium currents (IKAS) are heterogeneously up-regulated in failing hearts. We hypothesized that IKAS influences the location and stability of rotors during VF. Methods and Results Optical mapping was performed on 9 rabbit hearts with pacing induced heart failure. The epicardial RV and LV were simultaneously mapped in a Langendorff preparation. At baseline and after apamin (100 nmol/L) infusion, the APD80 was determined and VF was induced. Areas with a greater than 50% increase in the maximum APD (ΔAPD) after apamin were considered to have a high IKAS distribution. At baseline, the distribution density of phase singularities (PS) during VF in high IKAS distribution areas was higher than in other areas (0.0035±.0011 vs 0.0014±0.0010 PS/pixel, P=0.004). In addition, high dominant frequencies (DF) also co-localized to high IKAS distribution areas (26.0 vs 17.9 Hz, P=0.003). These correlations were eliminated during VF after apamin infusion, as the number of PS (17.2 versus 11.0, P=0.009), and DFs (22.1 vs 16.2 Hz, P=0.022), were all significantly decreased. In addition, reentrant spiral waves became unstable after apamin infusion and the duration of VF decreased. Conclusions The IKAS current influences the mechanism of VF in failing hearts as PS, high DFs, and reentrant spiral waves all correlated to areas of high IKAS. Apamin eliminated this relationship and reduced VF vulnerability. PMID:28213506

Review: history of the amyloid fibril.

PubMed

Sipe, J D; Cohen, A S

2000-06-01

Rudolph Virchow, in 1854, introduced and popularized the term amyloid to denote a macroscopic tissue abnormality that exhibited a positive iodine staining reaction. Subsequent light microscopic studies with polarizing optics demonstrated the inherent birefringence of amyloid deposits, a property that increased intensely after staining with Congo red dye. In 1959, electron microscopic examination of ultrathin sections of amyloidotic tissues revealed the presence of fibrils, indeterminate in length and, invariably, 80 to 100 A in width. Using the criteria of Congophilia and fibrillar morphology, 20 or more biochemically distinct forms of amyloid have been identified throughout the animal kingdom; each is specifically associated with a unique clinical syndrome. Fibrils, also 80 to 100 A in width, have been isolated from tissue homogenates using differential sedimentation or solubility. X-ray diffraction analysis revealed the fibrils to be ordered in the beta pleated sheet conformation, with the direction of the polypeptide backbone perpendicular to the fibril axis (cross beta structure). Because of the similar dimensions and tinctorial properties of the fibrils extracted from amyloid-laden tissues and amyloid fibrils in tissue sections, they have been assumed to be identical. However, the spatial relationship of proteoglycans and amyloid P component (AP), common to all forms of amyloid, to the putative protein only fibrils in tissues, has been unclear. Recently, it has been suggested that, in situ, amyloid fibrils are composed of proteoglycans and AP as well as amyloid proteins and thus resemble connective tissue microfibrils. Chemical and physical definition of the fibrils in tissues will be needed to relate the in vitro properties of amyloid protein fibrils to the pathogenesis of amyloid fibril formation in vivo. Copyright 2000 Academic Press.

Uniform spatial distribution of collagen fibril radii within tendon implies local activation of pC-collagen at individual fibrils

NASA Astrophysics Data System (ADS)

Rutenberg, Andrew D.; Brown, Aidan I.; Kreplak, Laurent

2016-08-01

Collagen fibril cross-sectional radii show no systematic variation between the interior and the periphery of fibril bundles, indicating an effectively constant rate of collagen incorporation into fibrils throughout the bundle. Such spatially homogeneous incorporation constrains the extracellular diffusion of collagen precursors from sources at the bundle boundary to sinks at the growing fibrils. With a coarse-grained diffusion equation we determine stringent bounds, using parameters extracted from published experimental measurements of tendon development. From the lack of new fibril formation after birth, we further require that the concentration of diffusing precursors stays below the critical concentration for fibril nucleation. We find that the combination of the diffusive bound, which requires larger concentrations to ensure homogeneous fibril radii, and lack of nucleation, which requires lower concentrations, is only marginally consistent with fully processed collagen using conservative bounds. More realistic bounds may leave no consistent concentrations. Therefore, we propose that unprocessed pC-collagen diffuses from the bundle periphery followed by local C-proteinase activity and subsequent collagen incorporation at each fibril. We suggest that C-proteinase is localized within bundles, at fibril surfaces, during radial fibrillar growth. The much greater critical concentration of pC-collagen, as compared to fully processed collagen, then provides broad consistency between homogeneous fibril radii and the lack of fibril nucleation during fibril growth.

Effects of Frequent Hemodialysis on Ventricular Volumes and Left Ventricular Remodeling

PubMed Central

Greene, Tom; Chertow, Glenn M.; Kliger, Alan S.; Stokes, John B.; Beck, Gerald J.; Daugirdas, John T.; Kotanko, Peter; Larive, Brett; Levin, Nathan W.; Mehta, Ravindra L.; Rocco, Michael; Sanz, Javier; Yang, Phillip C.; Rajagopalan, Sanjay

2013-01-01

Summary Background and objectives Higher left ventricular volume is associated with death in patients with ESRD. This work investigated the effects of frequent hemodialysis on ventricular volumes and left ventricular remodeling. Design, setting, participants, & measurements The Frequent Hemodialysis Network daily trial randomized 245 patients to 12 months of six times per week versus three times per week in-center hemodialysis; the Frequent Hemodialysis Network nocturnal trial randomized 87 patients to 12 months of six times per week nocturnal hemodialysis versus three times per week predominantly home-based hemodialysis. Left and right ventricular end systolic and diastolic volumes, left ventricular mass, and ejection fraction at baseline and end of the study were ascertained by cardiac magnetic resonance imaging. The ratio of left ventricular mass/left ventricular end diastolic volume was used as a surrogate marker of left ventricular remodeling. In each trial, the effect of frequent dialysis on left or right ventricular end diastolic volume was tested between predefined subgroups. Results In the daily trial, frequent hemodialysis resulted in significant reductions in left ventricular end diastolic volume (−11.0% [95% confidence interval, −16.1% to −5.5%]), left ventricular end systolic volume (−14.8% [−22.7% to −6.2%]), right ventricular end diastolic volume (−11.6% [−19.0% to −3.6%]), and a trend for right ventricular end systolic volume (−11.3% [−21.4% to 0.1%]) compared with conventional therapy. The magnitude of reduction in left and right ventricular end diastolic volumes with frequent hemodialysis was accentuated among patients with residual urine output<100 ml/d (P value [interaction]=0.02). In the nocturnal trial, there were no significant changes in left or right ventricular volumes. The frequent dialysis interventions had no substantial effect on the ratio of left ventricular mass/left ventricular end diastolic volume in either

Ivabradine, a novel heart rate slower: is it a sword of double blades in patients with idiopathic dilated cardiomyopathy?

PubMed

Rayan, Mona; Tawfik, Mazen; Alabd, Ali; Gamal, Amr

2011-08-01

To prospectively assess the safety and efficacy of ivabradine in patients with idiopathic dilated cardiomyopathy. We included 35 patients with idiopathic dilated cardiomyopathy with an ejection fraction (EF) <40% and heart rate >70 beats/min despite optimal medical therapy, according to the international guidelines in this prospective, non-randomized, single-arm, open-label safety study. Ivabradine was used as an add-on therapy to the maximally tolerated b-blocker in an increasing titrated dose till a target dose of 15 mg/day or resting heart rate of 60 beats/min for 3 months. During follow-up period the safety, patient tolerance and efficacy of this drug were assessed. All patients underwent 12-lead resting electrocardiography and Holter monitoring at inclusion and after 3 months. Statistical analysis was accomplished using paired t-test and Pearson correlation analysis. We found a significant reduction in the resting heart rate by a mean of 25.9 ± 9.4%, without a significant change of blood pressure. There was no prolongation of PR, QTc or QRS durations. Ventricular ectopic activity showed significant reduction (p<0.001). There was a significant correlation between the resting heart rate, NYHA and left ventricular ejection fraction (p<0.001 for both). One patient developed photopsia and decompensation was observed in another patient. Ivabradine is a safe and effective drug in reducing resting heart rate, improving NYHA functional class without undesirable effects on conduction parameters or ectopic activity.

Adverse postresuscitation myocardial effects elicited by buffer-induced alkalemia ameliorated by NHE-1 inhibition in a rat model of ventricular fibrillation.

PubMed

Lamoureux, Lorissa; Radhakrishnan, Jeejabai; Mason, Thomas G; Kraut, Jeffrey A; Gazmuri, Raúl J

2016-11-01

Major myocardial abnormalities occur during cardiac arrest and resuscitation including intracellular acidosis-partly caused by CO 2 accumulation-and activation of the Na + -H + exchanger isoform-1 (NHE-1). We hypothesized that a favorable interaction may result from NHE-1 inhibition during cardiac resuscitation followed by administration of a CO 2 -consuming buffer upon return of spontaneous circulation (ROSC). Ventricular fibrillation was electrically induced in 24 male rats and left untreated for 8 min followed by defibrillation after 8 min of cardiopulmonary resuscitation (CPR). Rats were randomized 1:1:1 to the NHE-1 inhibitor zoniporide or vehicle during CPR and disodium carbonate/sodium bicarbonate buffer or normal saline (30 ml/kg) after ROSC. Survival at 240 min declined from 100% with Zoniporide/Saline to 50% with Zoniporide/Buffer and 25% with Vehicle/Buffer (P = 0.004), explained by worsening postresuscitation myocardial dysfunction. Marked alkalemia occurred after buffer administration along with lactatemia that was maximal after Vehicle/Buffer, attenuated by Zoniporide/Buffer, and minimal with Zoniporide/Saline [13.3 ± 4.8 (SD), 9.2 ± 4.6, and 2.7 ± 1.0 mmol/l; P ≤ 0.001]. We attributed the intense postresuscitation lactatemia to enhanced glycolysis consequent to severe buffer-induced alkalemia transmitted intracellularly by an active NHE-1. We attributed the worsened postresuscitation myocardial dysfunction also to severe alkalemia intensifying Na + entry via NHE-1 with consequent Ca 2+ overload injuring mitochondria, evidenced by increased plasma cytochrome c Both buffer-induced effects were ameliorated by zoniporide. Accordingly, buffer-induced alkalemia after ROSC worsened myocardial function and survival, likely through enhancing NHE-1 activity. Zoniporide attenuated these effects and uncovered a complex postresuscitation acid-base physiology whereby blood pH drives NHE-1 activity and compromises mitochondrial function and integrity along

A Statistical Atrioventricular Node Model Accounting for Pathway Switching During Atrial Fibrillation.

PubMed

Henriksson, Mikael; Corino, Valentina D A; Sornmo, Leif; Sandberg, Frida

2016-09-01

The atrioventricular (AV) node plays a central role in atrial fibrillation (AF), as it influences the conduction of impulses from the atria into the ventricles. In this paper, the statistical dual pathway AV node model, previously introduced by us, is modified so that it accounts for atrial impulse pathway switching even if the preceding impulse did not cause a ventricular activation. The proposed change in model structure implies that the number of model parameters subjected to maximum likelihood estimation is reduced from five to four. The model is evaluated using the data acquired in the RATe control in atrial fibrillation (RATAF) study, involving 24-h ECG recordings from 60 patients with permanent AF. When fitting the models to the RATAF database, similar results were obtained for both the present and the previous model, with a median fit of 86%. The results show that the parameter estimates characterizing refractory period prolongation exhibit considerably lower variation when using the present model, a finding that may be ascribed to fewer model parameters. The new model maintains the capability to model RR intervals, while providing more reliable parameters estimates. The model parameters are expected to convey novel clinical information, and may be useful for predicting the effect of rate control drugs.

Effect of Sleep Apnea and Continuous Positive Airway Pressure on Cardiac Structure and Recurrence of Atrial Fibrillation

PubMed Central

Neilan, Tomas G.; Farhad, Hoshang; Dodson, John A.; Shah, Ravi V.; Abbasi, Siddique A.; Bakker, Jessie P.; Michaud, Gregory F.; van der Geest, Rob; Blankstein, Ron; Steigner, Michael; John, Roy M.; Jerosch‐Herold, Michael; Malhotra, Atul; Kwong, Raymond Y.

2013-01-01

Background Sleep apnea (SA) is associated with an increased risk of atrial fibrillation (AF). We sought to determine the effect of SA on cardiac structure in patients with AF, whether therapy for SA was associated with beneficial cardiac structural remodelling, and whether beneficial cardiac structural remodelling translated into a reduced risk of recurrence of AF after pulmonary venous isolation (PVI). Methods and Results A consecutive group of 720 patients underwent a cardiac magnetic resonance study before PVI. Patients with SA (n=142, 20%) were more likely to be male, diabetic, and hypertensive and have an increased pulmonary artery pressure, right ventricular volume, atrial dimensions, and left ventricular mass. Treated SA was defined as duration of continuous positive airway pressure therapy of >4 hours per night. Treated SA patients (n=71, 50%) were more likely to have paroxysmal AF, a lower blood pressure, lower ventricular mass, and smaller left atrium. During a follow‐up of 42 months, AF recurred in 245 patients. The cumulative incidence of AF recurrence was 51% in patients with SA, 30% in patients without SA, 68% in patients with untreated SA, and 35% in patients with treated SA. In a multivariable model, the presence of SA (hazard ratio 2.79, CI 1.97 to 3.94, P<0.0001) and untreated SA (hazard ratio 1.61, CI 1.35 to 1.92, P<0.0001) were highly associated with AF recurrence. Conclusions Patients with SA have an increased blood pressure, pulmonary artery pressure, right ventricular volume, left atrial size, and left ventricular mass. Therapy with continuous positive airway pressure is associated with lower blood pressure, atrial size, and ventricular mass, and a lower risk of AF recurrence after PVI. PMID:24275628

Idiopathic Inflammatory Myopathies

PubMed Central

Dimachkie, Mazen M.; Barohn, Richard J.

2012-01-01

The idiopathic inflammatory myopathies are a group of rare disorders including polymyositis (PM), dermatomyositis (DM), and autoimmune necrotizing myopathies (NMs). The idiopathic inflammatory myopathies share many similarities. They present acutely, subacutely, or chronically with marked proximal and symmetric muscle weakness, except for associated distal and asymmetric weakness in inclusion body myositis. The idiopathic inflammatory myopathies also share a variable degree of creatine kinase (CK) elevation and a nonspecifically abnormal electromyogram demonstrating an irritative myopathy. The muscle pathology demonstrates inflammatory exudates of variable distribution within the muscle fascicle. Despite these similarities, the idiopathic inflammatory myopathies are a heterogeneous group. The overlap syndrome (OS) refers to the association of PM, DM, or NM with connective tissue disease, such as scleroderma or systemic lupus erythematosus. In addition to elevated antinuclear antibodies (ANA), patients with OS may be weaker in the proximal arms than the legs mimicking the pattern seen in some muscular dystrophies. In this review, we focus on DM, PM, and NM and examine current and promising therapies. PMID:23117947

[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.

Clinical significance of J-wave in elite athletes.

PubMed

Pelliccia, Antonio; Quattrini, Filippo M

2015-01-01

The J-wave pattern on 12-lead ECG is traditionally defined as a positive deflection at junction between the end of the QRS and the beginning of the ST-segment. This pattern has recently been associated with increased risk for idiopathic ventricular fibrillation in the absence of cardiovascular disease. The interest for the clinical significance of J-wave pattern as a potential ECG hallmark of high risk for cardiac arrest has recently been reinforced by the growing practice of ECG screening, such as occurs in large population of young competitive athletes. The available scientific evidence shows that the J-wave pattern is relatively common in trained athletes (ranging from 14% to 44%) and, differently from subjects who suffered from ventricular fibrillation, commonly localized in lateral leads while it is relatively rare to be found in inferior leads. Furthermore the J-wave pattern has been demonstrated to be a dynamic phenomenon related to the training status, with the larger prominence at the peak of training and with an inverse relation between magnitude of J-wave and heart rate. In addition the J-wave pattern is usually associated with other ECG changes, such as increased QRS voltages and ST-segment elevation, as well as LV remodeling, suggesting that it likely represents another expression of the physiologic athlete's heart. Finally the scientific data available demonstrated that during a medium follow-up period the J-wave pattern does not convey risk for adverse cardiac events, including sudden death or ventricular tachyarrhythmias. Copyright © 2015 Elsevier Inc. All rights reserved.

Non-Invasive Assessment of Susceptibility to Ventricular Arrhythmias During Simulated Microgravity

NASA Technical Reports Server (NTRS)

Cohen, Richard J.

1999-01-01

The Cardiovascular Alterations Team is currently conducting studies to determine what alterations in hemodynamic regulation result from sixteen days of simulated microgravity exposure in normal human subjects. In this project we make additional measurements on these same study subjects in order to determine whether there is an increase in susceptibility to ventricular arrhythmias resulting from simulated microgravity exposure. Numerous anecdotal and documented reports from the past 30 years suggest that the incidence of ventricular arrhythmias among astronauts is increased during space flight. For example, documented runs of ventricular tachycardia have been recorded from crew members of Skylab and Mir, there was much attention given by the lay press to Mir Commander Vasily Tslbliyev's complaints of heart rhythm irregularities in July of 1997, and cardiovascular mechanisms may have been causal in the recent death of an experimental primate shortly after return from space. In 1986, a Mir cosmonaut, Alexander Laveikin, was brought home and replaced with an alternate cosmonaut as a result of cardiac dysrhythmias that began during extravehicular activity. Furthermore, at a joint NASA/NSBRI workshop held in January 1998, cardiac arrhythmias were identified as the highest priority cardiovascular risk to a human Mars mission. Despite the evidence for the risk of a potentially lethal arrhythmia resulting from microgravity exposure, the effects of space flight and the associated physiologic stresses on cardiac conduction processes are not known, and an increase in cardiac susceptibility to arrhythmias has never been quantified. In this project, we are determining whether simulated space flight increases the risk of developing life-threatening heart rhythm disturbances such as sustained ventricular tachycardia (defined as ventricular tachycardia lasting at least 30 seconds or resulting in hemodynamic collapse) and ventricular fibrillation. We are obtaining measures of

Venturing into ventricular arrhythmia storm: a systematic review and meta-analysis.

PubMed

Nayyar, Sachin; Ganesan, Anand N; Brooks, Anthony G; Sullivan, Thomas; Roberts-Thomson, Kurt C; Sanders, Prashanthan

2013-02-01

Ablation has substantial evidence base in the management of ventricular arrhythmia (VA). It can be a 'lifesaving' procedure in the acute setting of VA storm. Current reports on ablation in VA storm are in the form of small series and have relative small representation in a large observational series. The purpose of this study was to systematically synthesize the available literature to appreciate the efficacy and safety of ablation in the setting of VA storm. The medical electronic databases through 31 January 2012 were searched. Ventricular arrhythmia storm was defined as recurrent (≥ 3 episodes or defibrillator therapies in 24 h) or incessant (continuous >12 h) VA. Studies reporting data on VA storm patients at the individual or study level were included. A total of 471 VA storm patients from 39 publications were collated for the analysis. All VAs were successfully ablated in 72% [95% confidence interval (CI) 71-89%] and 9% (95% CI: 3-10%) had a failed procedure. Procedure-related mortality occurred in three patients (0.6%). Only 6% patients had a recurrence of VA storm. The recurrence of VA was significantly higher after ablation for arrhythmic storm of monomorphic ventricular tachycardia (VT) relative to ventricular fibrillation or polymorphic VT with underlying cardiomyopathy (odds ratio 3.76; 95% CI: 1.65-8.57; P = 0.002). During the follow-up (61 ± 37 weeks), 17% of patients died (heart failure 62%, arrhythmias 23%, and non-cardiac 15%) with 55% deaths occurring within 12 weeks of intervention. The odds of death were four times higher after a failed procedure compared with those with a successful procedure (95% CI: 2.04-8.01, P < 0.001). Ventricular arrhythmia storm ablation has high-acute success rates, with a low rate of recurrent storms. Heart failure is the dominant cause of death in the long term. Failure of the acute procedure carries a high mortality.

Heart rate variability in idiopathic dilated cardiomyopathy: relation to disease severity and prognosis.

PubMed Central

Yi, G.; Goldman, J. H.; Keeling, P. J.; Reardon, M.; McKenna, W. J.; Malik, M.

1997-01-01

OBJECTIVE: To assess the clinical importance of heart rate variability (HRV) in patients with idiopathic dilated cardiomyopathy (DCM). PATIENTS AND METHODS: Time domain analysis of 24 hour HRV was performed in 64 patients with DCM, 19 of their relatives with left ventricular enlargement (possible early DCM), and 33 healthy control subjects. RESULTS: Measures of HRV were reduced in patients with DCM compared with controls (P < 0.05). HRV parameters were similar in relatives and controls. Measures of HRV were lower in DCM patients in whom progressive heart failure developed (n = 28) than in those who remained clinically stable (n = 36) during a follow up of 24 (20) months (P = 0.0001). Reduced HRV was associated with NYHA functional class, left ventricular end diastolic dimension, reduced left ventricular ejection fraction, and peak exercise oxygen consumption (P < 0.05) in all patients. DCM patients with standard deviation of normal to normal RR intervals calculated over the 24 hour period (SDNN) < 50 ms had a significantly lower survival rate free of progressive heart failure than those with SDNN > 50 ms (P = 0.0002, at 12 months; P = 0.0001, during overall follow up). Stepwise multiple regression analysis showed that SDNN < 50 ms identified, independently of other clinical variables, patients who were at increased risk of developing progressive heart failure (P = 0.0004). CONCLUSIONS: HRV is reduced in patients with DCM and related to disease severity. HRV is clinically useful as an early non-invasive marker of DCM deterioration. PMID:9068391

[Wearable Automatic External Defibrillators].

PubMed

Luo, Huajie; Luo, Zhangyuan; Jin, Xun; Zhang, Leilei; Wang, Changjin; Zhang, Wenzan; Tu, Quan

2015-11-01

Defibrillation is the most effective method of treating ventricular fibrillation(VF), this paper introduces wearable automatic external defibrillators based on embedded system which includes EGG measurements, bioelectrical impedance measurement, discharge defibrillation module, which can automatic identify VF signal, biphasic exponential waveform defibrillation discharge. After verified by animal tests, the device can realize EGG acquisition and automatic identification. After identifying the ventricular fibrillation signal, it can automatic defibrillate to abort ventricular fibrillation and to realize the cardiac electrical cardioversion.

Targeted ablation of cardiac sympathetic neurons improves ventricular electrical remodelling in a canine model of chronic myocardial infarction.

PubMed

Xiong, Liang; Liu, Yu; Zhou, Mingmin; Wang, Guangji; Quan, Dajun; Shen, Caijie; Shuai, Wei; Kong, Bin; Huang, Congxin; Huang, He

2018-05-31

The purpose of this study was to evaluate the cardiac electrophysiologic effects of targeted ablation of cardiac sympathetic neurons (TACSN) in a canine model of chronic myocardial infarction (MI). Thirty-eight anaesthetized dogs were randomly assigned into the sham-operated, MI, and MI-TACSN groups, respectively. Myocardial infarction-targeted ablation of cardiac sympathetic neuron was induced by injecting cholera toxin B subunit-saporin compound in the left stellate ganglion (LSG). Five weeks after surgery, the cardiac function, heart rate variability (HRV), ventricular electrophysiological parameters, LSG function and neural activity, serum norepinephrine (NE), nerve growth factor (NGF), and brain natriuretic peptide (BNP) levels were measured. Cardiac sympathetic innervation was determined with immunofluorescence staining of growth associated protein-43 (GAP43) and tyrosine hydroxylase (TH). Compared with MI group, TACSN significantly improved HRV, attenuated LSG function and activity, prolonged corrected QT interval, decreased Tpeak-Tend interval, prolonged ventricular effective refractory period (ERP), and action potential duration (APD), decreased the slopes of APD restitution curves, suppressed the APD alternans, increased ventricular fibrillation threshold, and reduced serum NE, NGF, and BNP levels. Moreover, the densities of GAP43 and TH-positive nerve fibres in the infarcted border zone in the MI-TACSN group were lower than those in the MI group. Targeted ablation of cardiac sympathetic neuron attenuates sympathetic remodelling and improves ventricular electrical remodelling in the chronic phase of MI. These data suggest that TACSN may be a novel approach to treating ventricular arrhythmias.

The clinical and molecular genetic features of idiopathic infantile periodic alternating nystagmus

PubMed Central

Thomas, Mervyn G.; Crosier, Moira; Lindsay, Susan; Kumar, Anil; Thomas, Shery; Araki, Masasuke; Talbot, Chris J.; McLean, Rebecca J.; Surendran, Mylvaganam; Taylor, Katie; Leroy, Bart P.; Moore, Anthony T.; Hunter, David G.; Hertle, Richard W.; Tarpey, Patrick; Langmann, Andrea; Lindner, Susanne; Brandner, Martina

2011-01-01

FRMD7 expression in neuronal tissue with strong hybridization signals within the afferent arms of the vestibulo-ocular reflex consisting of the otic vesicle, cranial nerve VIII and vestibular ganglia. Similarly within the afferent arm of the optokinetic reflex we showed expression in the developing neural retina and ventricular zone of the optic stalk. Strong FRMD7 expression was seen in rhombomeres 1 to 4, which give rise to the cerebellum and the common integrator site for both these reflexes (vestibular nuclei). Based on the expression and phenotypic data, we hypothesize that periodic alternating nystagmus arises from instability of the optokinetic-vestibular systems. This study shows for the first time that mutations in FRMD7 can cause idiopathic infantile periodic alternating nystagmus and may affect neuronal circuits that have been implicated in acquired forms. PMID:21303855

Echocardiography-based hemodynamic management of left ventricular diastolic dysfunction: a feasibility and safety study.

PubMed

Shillcutt, Sasha K; Montzingo, Candice R; Agrawal, Ankit; Khaleel, Maseeha S; Therrien, Stacey L; Thomas, Walker R; Porter, Thomas R; Brakke, Tara R

2014-11-01

Patients with left ventricular diastolic dysfunction (LVDD) are at increased risk of postoperative adverse events. The primary aim of this study was to evaluate the safety and feasibility of using echocardiography-guided hemodynamic management (EGHEM) during surgery in subjects with LVDD compared to conventional management. The feasibility of using echocardiography to direct a treatment algorithm and clinical outcomes were compared for safety between groups. Subjects were screened for LVDD by preoperative transthoracic echocardiography (TTE) and randomized to the conventional or EGHEM group. Subjects in EGHEM received hemodynamic management based on left ventricular filling patterns on transesophageal echocardiography (TEE). Primary outcomes measured were the feasibility to obtain TEE images and follow a TEE-based treatment algorithm. Safety outcomes also compared the following clinical differences between groups: length of hospitalization, incidence of atrial fibrillation, congestive heart failure (CHF), myocardial infarction, cerebrovascular accident, transient ischemic attack and renal failure measured 30 days postoperatively. Population consisted of 28 surgical subjects (14 in conventional group and 14 in EGHEM group). Mean subject age was 73.4 ± 6.7 years (36% male) in conventional group and 65.9 ± 14.4 years (36% male) in EGHEM group. Procedures included orthopedic (conventional = 29%, EGHEM 36%), general (conventional = 50%, EGHEM = 36%), vascular (conventional = 7%, EGHEM = 21%), and thoracic (conventional = 14%, EGHEM = 7%). There was no statistically significant difference in adverse clinical events between the 2 groups. The EGHEM group had less CHF, atrial fibrillation, and shorter length of stay. Echocardiography-guided hemodynamic management of patients with LVDD during surgery is feasible and may be a safe alternative to conventional management. © 2014, Wiley Periodicals, Inc.

Value of right ventricular mapping in patients with postinfarction ventricular tachycardia.

PubMed

Yokokawa, Miki; Good, Eric; Crawford, Thomas; Chugh, Aman; Pelosi, Frank; Latchamsetty, Rakesh; Oral, Hakan; Morady, Fred; Bogun, Frank

2012-06-01

Postinfarction ventricular tachycardia (VT) typically involves the left ventricular endocardium. Right ventricular involvement in the arrhythmogenic substrate of postinfarction VT is considered unusual. To assess the role of right ventricular mapping and ablation in patients with prior septal myocardial infarction. From among 37 consecutive patients with recurrent postinfarction VT, 18 patients with evidence of left ventricular septal involvement of myocardial infarction were identified; these patients were the subjects of this report. In these 18 patients, 166 VTs (cycle length 372 ± 117 ms) were induced. Right ventricular voltage mapping was performed in all 18 patients with left ventricular septal myocardial infarction. Right ventricular voltage mapping showed areas of low voltage in 11 patients; pace mapping from these areas revealed matching pace maps for 17 VTs, and radiofrequency ablation from the right ventricular endocardium but not the left ventricular endocardium eliminated 14 of 17 VTs. VTs with critical components in the right ventricle had a left bundle branch block morphology that had similar characteristics as left bundle branch block VTs with critical areas involving the left ventricular septum. Patients with right ventricular VT breakthrough sites had a lower ejection fraction than did patients without VT breaking out on the right ventricular septum (18% ± 5% vs 33% ± 15%; P = .01). Right ventricular mapping and ablation may be necessary in order to eliminate all inducible VTs in patients with postinfarction VT. More than half the patients with septal myocardial infarction have right ventricular septal areas that are critical for postinfarction VT and that cannot be eliminated by left ventricular ablation alone. Copyright © 2012 Heart Rhythm Society. All rights reserved.

Catecholamine-mediated arrhythmias in acute myocardial infarction. Experimental evidence and role of beta-adrenoceptor blockade.

PubMed

Opie, L H; Lubbe, W F

1979-11-24

Ventricular fibrillation is a major mechanism of sudden death. The cellular link between catecholamine activity and the development of serious ventricular arrhythmias may be in the formation of cyclic adenosine monophosphate (cAMP). Cyclic AMP and agents promoting cAMP accumulation allow development of slow responses which, especially in the presence of regional ischaemia, could develop into ventricular fibrillation. The role of beta-antagonist agents in the therapy of acute myocardial infarction is analysed in relation to the hypothesis linking cAMP and ventricular fibrillation. Reasons for the limited effectiveness of anti-arrhythmic therapy with beta-antagonist agents are given.

Increased Risk of Paroxysmal Atrial Fibrillation Episodes Associated with Acute Increases in Ambient Air Pollution

PubMed Central

Rich, David Q.; Mittleman, Murray A.; Link, Mark S.; Schwartz, Joel; Luttmann-Gibson, Heike; Catalano, Paul J.; Speizer, Frank E.; Gold, Diane R.; Dockery, Douglas W.

2006-01-01

Objectives: We reported previously that 24-hr moving average ambient air pollution concentrations were positively associated with ventricular arrhythmias detected by implantable cardioverter defibrillators (ICDs). ICDs also detect paroxysmal atrial fibrillation episodes (PAF) that result in rapid ventricular rates. In this same cohort of ICD patients, we assessed the association between ambient air pollution and episodes of PAF. Design: We performed a case–crossover study. Participants: Patients who lived in the Boston, Massachusetts, metropolitan area and who had ICDs implanted between June 1995 and December 1999 (n = 203) were followed until July 2002. Evaluations/Measurements: We used conditional logistic regression to explore the association between community air pollution and 91 electrophysiologist-confirmed episodes of PAF among 29 subjects. Results: We found a statistically significant positive association between episodes of PAF and increased ozone concentration (22 ppb) in the hour before the arrhythmia (odds ratio = 2.08; 95% confidence interval = 1.22, 3.54; p = 0.001). The risk estimate for a longer (24-hr) moving average was smaller, thus suggesting an immediate effect. Positive but not statistically significant risks were associated with fine particles, nitrogen dioxide, and black carbon. Conclusions: Increased ambient O3 pollution was associated with increased risk of episodes of rapid ventricular response due to PAF, thereby suggesting that community air pollution may be a precipitant of these events. PMID:16393668

Re-entry using anatomically determined isthmuses: a curable ventricular tachycardia in repaired congenital heart disease.

PubMed

Kapel, Gijsbert F L; Reichlin, Tobias; Wijnmaalen, Adrianus P; Piers, Sebastiaan R D; Holman, Eduard R; Tedrow, Usha B; Schalij, Martin J; Stevenson, William G; Zeppenfeld, Katja

2015-02-01

Ventricular tachycardia (VT) is an important cause of late morbidity and mortality in repaired congenital heart disease. The substrate often includes anatomic isthmuses that can be transected by radiofrequency catheter ablation similar to isthmus block for atrial flutter. This study evaluates the long-term efficacy of isthmus block for treatment of re-entry VT in adults with repaired congenital heart disease. Thirty-four patients (49±13 years; 74% male) with repaired congenital heart disease who underwent radiofrequency catheter ablation of VT in 2 centers were included. Twenty-two (65%) had a preserved left and right ventricular function. Patients were inducible for 1 (interquartile range, 1-2) VT, median cycle length: 295 ms (interquartile range, 242-346). Ablation aimed to transect anatomic isthmuses containing VT re-entry circuit isthmuses. Procedural success was defined as noninducibility of any VT and transection of the anatomic isthmus and was achieved in 25 (74%) patients. During long-term follow-up (46±29 months), all patients with procedural success (18/25 with internal cardiac defibrillators) were free of VT recurrence but 7 of 18 experienced internal cardiac defibrillator-related complications. One patient with procedural success and depressed cardiac function received an internal cardiac defibrillator shock for ventricular fibrillation. None of the 18 patients (12/18 with internal cardiac defibrillators) with complete success and preserved cardiac function experienced any ventricular arrhythmia. In contrast, VT recurred in 4 of 9 patients without procedural success. Four patients died from nonarrhythmic causes. In patients with repaired congenital heart disease with preserved ventricular function and isthmus-dependent re-entry, VT isthmus ablation can be curative. © 2014 American Heart Association, Inc.

Transmission electron microscopy of amyloid fibrils.

PubMed

Gras, Sally L; Waddington, Lynne J; Goldie, Kenneth N

2011-01-01

Transmission Electron Microscopy of negatively stained and cryo-prepared specimens allows amyloid fibrils to be visualised at high resolution in a dried or a hydrated state, and is an essential method for characterising the morphology of fibrils and pre-fibrillar species. We outline the key steps involved in the preparation and observation of samples using negative staining and cryo-electron preservation. We also discuss methods to measure fibril characteristics, such as fibril width, from electron micrographs.

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.

Kinetics and mechanical stability of the fibril state control fibril formation time of polypeptide chains: A computational study

NASA Astrophysics Data System (ADS)

Kouza, Maksim; Co, Nguyen Truong; Li, Mai Suan; Kmiecik, Sebastian; Kolinski, Andrzej; Kloczkowski, Andrzej; Buhimschi, Irina Alexandra

2018-06-01

Fibril formation resulting from protein misfolding and aggregation is a hallmark of several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Despite much progress in the understanding of the protein aggregation process, the factors governing fibril formation rates and fibril stability have not been fully understood. Using lattice models, we have shown that the fibril formation time is controlled by the kinetic stability of the fibril state but not by its energy. Having performed all-atom explicit solvent molecular dynamics simulations with the GROMOS43a1 force field for full-length amyloid beta peptides Aβ40 and Aβ42 and truncated peptides, we demonstrated that kinetic stability can be accessed via mechanical stability in such a way that the higher the mechanical stability or the kinetic stability, the faster the fibril formation. This result opens up a new way for predicting fibril formation rates based on mechanical stability that may be easily estimated by steered molecular dynamics.

Usefulness of bedside tissue Doppler echocardiography and B-type natriuretic peptide (BNP) in differentiating congestive heart failure from noncardiac cause of acute dyspnea in elderly patients with a normal left ventricular ejection fraction and permanent, nonvalvular atrial fibrillation: insights from a prospective, monocenter study.

PubMed

Arques, Stephane; Roux, Emmanuel; Sbragia, Pascal; Pieri, Bertrand; Gelisse, Richard; Luccioni, Roger; Ambrosi, Pierre

2007-05-01

The incremental role of bedside tissue Doppler echocardiography and B-type natriuretic peptide (BNP) over the clinical judgment has been recently reported in the emergency diagnosis of congestive heart failure with a normal left ventricular ejection fraction (HFNEF). However, how well does this diagnostic strategy be applicable in the setting of atrial fibrillation is unknown. To investigate the usefulness of bedside tissue Doppler echocardiography and BNP in the emergency diagnosis of HFNEF in elderly patients with permanent, nonvalvular atrial fibrillation. Forty-one consecutive elderly patients with an ejection fraction > or =50% (mean age 84 years; 22 with HFNEF and 19 with noncardiac cause), hospitalized for acute dyspnea at rest, were prospectively enrolled; bedside septal E/Ea and BNP were obtained at admission. By multivariable logistic regression analysis including the clinical judgment of heart failure, E/Ea and BNP, E/Ea (P = 0.014) and BNP (P = 0.018) provided independent diagnostic information. Optimal cutoffs were 13 for E/Ea (area under the ROC curve of 0.846, P < 0.0001; sensitivity 81.8%, specificity 89.5%) and 253 pg/ml for BNP (area under the ROC curve of 0.928, P < 0.0001; sensitivity 86.4%, specificity 89.5%). The concordance between the clinical judgment and BNP concentration at the cutoff of 253 pg/ml correctly classified 24 of 25 patients; E/Ea at the cutoff of 13 correctly classified 14 of the 16 patients with discrepancy. Bedside tissue Doppler echocardiography and BNP provide useful additional diagnostic information over the clinical judgment for the emergency diagnosis of HFNEF in elderly patients with permanent, nonvalvular atrial fibrillation.

Ranolazine effectively suppresses atrial fibrillation in the setting of heart failure.

PubMed

Burashnikov, Alexander; Di Diego, José M; Barajas-Martínez, Hector; Hu, Dan; Zygmunt, Andrew C; Cordeiro, Jonathan M; Moise, N Sydney; Kornreich, Bruce G; Belardinelli, Luiz; Antzelevitch, Charles

2014-07-01

There is a critical need for safer and more effective pharmacological management of atrial fibrillation (AF) in the setting of heart failure (HF). This study investigates the electrophysiological, antiarrhythmic, and proarrhythmic effects of a clinically relevant concentration of ranolazine (5 μmol/L) in coronary-perfused right atrial and left ventricular preparations isolated from the hearts of HF dogs. HF was induced by ventricular tachypacing (2-6 weeks at 200-240 beats per minute; n=17). Transmembrane action potentials were recorded using standard microelectrode techniques. In atria, ranolazine slightly prolonged action potential duration but significantly depressed sodium channel current-dependent parameters causing a reduction of maximum rate of rise of the action potential upstroke, a prolongation of the effective refractory period secondary to the development of postrepolarization refractoriness, and an increase in diastolic threshold of excitation and atrial conduction time. Ranolazine did not significantly alter these parameters or promote arrhythmias in the ventricles. Ranolazine produced greater inhibition of peak sodium channel current in atrial cells isolated from HF versus normal dogs. A single premature beat reproducibly induced self-terminating AF in 10 of 17 atria. Ranolazine (5 μmol/L) suppressed induction of AF in 7 of 10 (70%) atria. In the remaining 3 atria, ranolazine reduced frequency and duration of AF. Our results demonstrate more potent suppression of AF by ranolazine in the setting of HF than previously demonstrated in nonfailing hearts and absence of ventricular proarrhythmia. The data suggest that ranolazine may be of benefit as an alternative to amiodarone and dofetilide in the management of AF in patients with HF. © 2014 American Heart Association, Inc.

Comparison of monocyte gene expression among patients with neurocysticercosis-associated epilepsy, Idiopathic Epilepsy and idiopathic headaches in India.

PubMed

Prabhakaran, Vasudevan; Drevets, Douglas A; Ramajayam, Govindan; Manoj, Josephine J; Anderson, Michael P; Hanas, Jay S; Rajshekhar, Vedantam; Oommen, Anna; Carabin, Hélène

2017-06-01

Neurocysticercosis (NCC), a neglected tropical disease, inflicts substantial health and economic costs on people living in endemic areas such as India. Nevertheless, accurate diagnosis using brain imaging remains poorly accessible and too costly in endemic countries. The goal of this study was to test if blood monocyte gene expression could distinguish patients with NCC-associated epilepsy, from NCC-negative imaging lesion-free patients presenting with idiopathic epilepsy or idiopathic headaches. Patients aged 18 to 51 were recruited from the Department of Neurological Sciences, Christian Medical College and Hospital, Vellore, India, between January 2013 and October 2014. mRNA from CD14+ blood monocytes was isolated from 76 patients with NCC, 10 Recovered NCC (RNCC), 29 idiopathic epilepsy and 17 idiopathic headaches patients. A preliminary microarray analysis was performed on six NCC, six idiopathic epilepsy and four idiopathic headaches patients to identify genes differentially expressed in NCC-associated epilepsy compared with other groups. This analysis identified 1411 upregulated and 733 downregulated genes in patients with NCC compared to Idiopathic Epilepsy. Fifteen genes up-regulated in NCC patients compared with other groups were selected based on possible relevance to NCC, and analyzed by qPCR in all patients' samples. Differential gene expression among patients was assessed using linear regression models. qPCR analysis of 15 selected genes showed generally higher gene expression among NCC patients, followed by RNCC, idiopathic headaches and Idiopathic Epilepsy. Gene expression was also generally higher among NCC patients with single cyst granulomas, followed by mixed lesions and single calcifications. Expression of certain genes in blood monocytes can distinguish patients with NCC-related epilepsy from patients with active Idiopathic Epilepsy and idiopathic headaches. These findings are significant because they may lead to the development of new tools to

Aromatic interactions are not required for amyloid fibril formation by islet amyloid polypeptide but do influence the rate of fibril formation and fibril morphology.

PubMed

Marek, Peter; Abedini, Andisheh; Song, BenBen; Kanungo, Mandakini; Johnson, Megan E; Gupta, Ruchi; Zaman, Warda; Wong, Stanislaus S; Raleigh, Daniel P

2007-03-20

Amyloid formation has been implicated in a wide range of human diseases, and a diverse set of proteins is involved. There is considerable interest in elucidating the interactions which lead to amyloid formation and which contribute to amyloid fibril stability. Recent attention has been focused upon the potential role of aromatic-aromatic and aromatic-hydrophobic interactions in amyloid formation by short to midsized polypeptides. Here we examine whether aromatic residues are necessary for amyloid formation by islet amyloid polypeptide (IAPP). IAPP is responsible for the formation of islet amyloid in type II diabetes which is thought to play a role in the pathology of the disease. IAPP is 37 residues in length and contains three aromatic residues, Phe-15, Phe-23, and Tyr-37. Structural models of IAPP amyloid fibrils postulate that Tyr-37 is near one of the phenylalanine residues, and it is known that Tyr-37 interacts with one of the phenylalanines during fibrillization; however, it is not known if aromatic-aromatic or aromatic-hydrophobic interactions are absolutely required for amyloid formation. An F15L/F23L/Y37L triple mutant (IAPP-3XL) was prepared, and its ability to form amyloid was tested. CD, thioflavin binding assays, AFM, and TEM measurements all show that the triple leucine mutant readily forms amyloid fibrils. The substitutions do, however, decrease the rate of fibril formation and alter the tendency of fibrils to aggregate. Thus, while aromatic residues are not an absolute requirement for amyloid formation by IAPP, they do play a role in the fibril assembly process.

Left ventricular inflow tract obstruction secondary to a myxoma in a dog.

PubMed

Fernandez-del Palacio, M Josefa; Sanchez, Joaquin; Talavera, Jesus; Martínez, Carlos

2011-01-01

This is the first description of a left ventricular inflow tract obstruction secondary to a myxoma in a dog. A 4 yr old, male fox terrier presented with a 1 mo history of cough and exercise intolerance. Expiratory dyspnea, pulmonary crackles, irregular cardiac rhythm, and a grade 4/6 pansystolic cardiac murmur over the left cardiac apex were the most important features on physical examination. The electrocardiogram revealed atrial fibrillation. Thoracic radiographs showed left-sided cardiac enlargement and mild pulmonary edema, especially in the hilar area. Two-dimensional transthoracic echocardiography showed severe left atrial dilation and a homogenous, echodense mass involving both leaflets of the mitral valve and the posteromedial papillary muscle, inducing mitral stenosis. Spectral Doppler echocardiography was consistent with severe left ventricular inflow tract obstruction secondary to a mass. Therapy for congestive heart failure was prescribed. Follow-up examinations of the dog 1 mo, 2 mo, and 6 mo after diagnosis showed an improvement in clinical signs, but similar echocardiographic features. Eleven months after diagnosis, the dog was euthanized at the owner's request because of recurrent congestive heart failure. The postmortem examination showed the cardiac tumor was consistent with a myxoma.

Synergistic Effect of Dofetilide and Mexiletine on Prevention of Atrial Fibrillation.

PubMed

Liu, Guizhi; Xue, Xiaolin; Gao, Chuanyu; Huang, Jiaqi; Qi, Datun; Zhang, Yanzhou; Dong, Jian-Zeng; Ma, Chang-Sheng; Yan, Gan-Xin

2017-05-18

Although atrial fibrillation (AF) is the most common abnormal heart rhythm and its prevalence continues to rise, there is a marked paucity of effective and safe antiarrhythmic drugs for AF. This study was done to test whether combined use of dofetilide and mexiletine exhibits not only a synergistic effect on AF suppression but also a safer profile in drug-induced ventricular proarrhythmias. The effects of dofetilide plus mexiletine on atrial effective refractory period (ERP), AF inducibility, QT, and QT-related ventricular arrhythmias were studied using the isolated arterially perfused rabbit atrial and ventricular wedge preparations. Dofetilide or mexiletine alone mildly to moderately prolonged atrial ERP, but their combined use produced a markedly rate-dependent increase in atrial ERP. Dofetilide (3 nmol/L) plus mexiletine (10 μmol/L) increased the ERP by 28.2% from 72.2±5.7 to 92.8±5.9 ms (n=9, P <0.01) at a pacing rate of 0.5 Hz and by 94.5% from 91.7±5.2 to 178.3±12.0 ms (n=9, P <0.01) at 3.3 Hz. Dofetilide plus mexiletine strongly suppressed AF inducibility. On the other hand, dofetilide at 10 nmol/L produced marked QT and T p-e prolongation, steeper QT-BCL and T p-e -BCL slopes, and induced early afterdepolarizations and torsade de pointes in the ventricular wedges. Mexiletine at 10 μmol/L reduced dofetilide-induced QT and T p-e prolongation, QT-BCL and T p-e -BCL slopes, and abolished early afterdepolarizations and torsade de pointes. In rabbits, combined use of dofetilide and mexiletine not only synergistically increases atrial ERP and effectively suppresses AF inducibility, but also markedly reduces QT liability and torsade de pointes risk posed by dofetilide alone. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Cross-seeding and cross-competition in mouse apolipoprotein A-II amyloid fibrils and protein A amyloid fibrils.

PubMed

Yan, Jingmin; Fu, Xiaoying; Ge, Fengxia; Zhang, Beiru; Yao, Junjie; Zhang, Huanyu; Qian, Jinze; Tomozawa, Hiroshi; Naiki, Hironobu; Sawashita, Jinko; Mori, Masayuki; Higuchi, Keiichi

2007-07-01

Murine senile [apolipoprotein A-II amyloid (AApoAII)] and reactive [protein A amyloid (AA)] amyloidosis are reported to be transmissible diseases via a seeding mechanism similar to that observed in the prion-associated disorders, although de novo amyloidogenesis and the progression of AApoAII or AA amyloidosis remain unclear. We examined the effect of co-injection of AApoAII and AA fibrils and multiple inflammatory stimuli in R1.P1-Apoa2(c) mice with the amyloidogenic Apoa2(c) allele. Both AApoAII and AA amyloidosis could be induced in this system, but the two types of amyloid fibrils preferentially promote the formation of the same type of fibrils while inhibiting the formation of the other. Furthermore, we demonstrate that AA or AApoAII amyloidosis could be cross-seeded by predeposited AApoAII or AA fibrils and that the predeposited amyloid fibrils were degraded when the fibril formation was reduced or stopped. In addition, a large proportion of the two amyloid fibrils colocalized during the formation of new fibrils in the spleen and liver. Thus, we propose that AApoAII and AA can both cross-seed and cross-compete with regard to amyloid formation, depending on the stage of amyloidogenesis. These results will aid in the clarification of the mechanisms of pathogenesis and progression of amyloid disorders.

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.

Evidence of structurally continuous collagen fibrils in tendons.

PubMed

Svensson, Rene B; Herchenhan, Andreas; Starborg, Tobias; Larsen, Michael; Kadler, Karl E; Qvortrup, Klaus; Magnusson, S Peter

2017-03-01

Tendons transmit muscle-generated force through an extracellular matrix of aligned collagen fibrils. The force applied by the muscle at one end of a microscopic fibril has to be transmitted through the macroscopic length of the tendon by mechanisms that are poorly understood. A key element in this structure-function relationship is the collagen fibril length. During embryogenesis short fibrils are produced but they grow rapidly with maturation. There is some controversy regarding fibril length in adult tendon, with mechanical data generally supporting discontinuity while structural investigations favor continuity. This study initially set out to trace the full length of individual fibrils in adult human tendons, using serial block face-scanning electron microscopy. But even with this advanced technique the required length could not be covered. Instead a statistical approach was used on a large volume of fibrils in shorter image stacks. Only a single end was observed after tracking 67.5mm of combined fibril lengths, in support of fibril continuity. To shed more light on this observation, the full length of a short tendon (mouse stapedius, 125μm) was investigated and continuity of individual fibrils was confirmed. In light of these results, possible mechanisms that could reconcile the opposing findings on fibril continuity are discussed. Connective tissues hold all parts of the body together and are mostly constructed from thin threads of the protein collagen (called fibrils). Connective tissues provide mechanical strength and one of the most demanding tissues in this regard are tendons, which transmit the forces generated by muscles. The length of the collagen fibrils is essential to the mechanical strength and to the type of damage the tissue may experience (slippage of short fibrils or breakage of longer ones). This in turn is important for understanding the repair processes after such damage occurs. Currently the issue of fibril length is contentious, but this

Prognostic implications of atrial fibrillation in patients undergoing myocardial perfusion single-photon emission computed tomography.

PubMed

Abidov, Aiden; Hachamovitch, Rory; Rozanski, Alan; Hayes, Sean W; Santos, Marcia M; Sciammarella, Maria G; Cohen, Ishac; Gerlach, James; Friedman, John D; Germano, Guido; Berman, Daniel S

2004-09-01

The aim of this research was to determine whether presence of atrial fibrillation (AF) provides incremental prognostic information relative to myocardial perfusion single-photon emission computed tomography (MPS) with respect to risk of cardiac death (CD). The prognostic significance of AF in patients undergoing MPS is not known. A total of 16,048 consecutive patients undergoing MPS were followed-up for a mean of 2.21 +/- 1.15 years for the development of CD. Of those, 384 patients (2.4%) had AF. Cox proportional hazards method was used to compare clinical and perfusion data for the prediction of CD in patients with and without AF. Atrial fibrillation was a significant predictor of CD in patients with normal (1.6% per year vs. 0.4% per year in non-AF patients), mildly abnormal (6.3% per year vs. 1.2% per year), and severely abnormal MPS (6.4% per year vs. 3.7% per year) (p < 0.001 for all). By multivariable analysis, AF patients had worse survival (p = 0.001) even after adjustment for the variables most predictive of CD: age, diabetes, shortness of breath, use of vasodilator stress, rest heart rate, and the nuclear variables. In the 4,239 patients with left ventricular ejection fraction evaluated by gated MPS, AF demonstrated incremental prognostic value not only over clinical and nuclear variables, but also over left ventricular ejection in predicting CD (p = 0.014). The presence of AF independently increases the risk of cardiac events over perfusion and function variables in patients undergoing MPS. Patients with AF have a high risk of CD, even when MPS is only mildly abnormal. Whether patients with AF and mildly abnormal MPS constitute a group more deserving of early referral to cardiac catheterization is a question warranting further study.

Average current is better than peak current as therapeutic dosage for biphasic waveforms in a ventricular fibrillation pig model of cardiac arrest.

PubMed

Chen, Bihua; Yu, Tao; Ristagno, Giuseppe; Quan, Weilun; Li, Yongqin

2014-10-01

Defibrillation current has been shown to be a clinically more relevant dosing unit than energy. However, the effects of average and peak current in determining shock outcome are still undetermined. The aim of this study was to investigate the relationship between average current, peak current and defibrillation success when different biphasic waveforms were employed. Ventricular fibrillation (VF) was electrically induced in 22 domestic male pigs. Animals were then randomized to receive defibrillation using one of two different biphasic waveforms. A grouped up-and-down defibrillation threshold-testing protocol was used to maintain the average success rate of 50% in the neighborhood. In 14 animals (Study A), defibrillations were accomplished with either biphasic truncated exponential (BTE) or rectilinear biphasic waveforms. In eight animals (Study B), shocks were delivered using two BTE waveforms that had identical peak current but different waveform durations. Both average and peak currents were associated with defibrillation success when BTE and rectilinear waveforms were investigated. However, when pathway impedance was less than 90Ω for the BTE waveform, bivariate correlation coefficient was 0.36 (p=0.001) for the average current, but only 0.21 (p=0.06) for the peak current in Study A. In Study B, a high defibrillation success (67.9% vs. 38.8%, p<0.001) was observed when the waveform delivered more average current (14.9±2.1A vs. 13.5±1.7A, p<0.001) while keeping the peak current unchanged. In this porcine model of VF, average current was better than peak current to be an adequate parameter to describe the therapeutic dosage when biphasic defibrillation waveforms were used. The institutional protocol number: P0805. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Reinforcement of polymeric structures with asbestos fibrils

NASA Technical Reports Server (NTRS)

Rader, C. A.; Schwartz, A. M.

1970-01-01

Investigation determines structural potential of asbestos fibrils. Methods are developed for dispersing macrofibers of the asbestos into colloidal-sized ultimate fibrils and incorporating these fibrils in matrices without causing reagglomeration.

New-Onset Atrial Fibrillation in the Critically Ill*

PubMed Central

Moss, Travis J.; Calland, James Forrest; Enfield, Kyle B.; Gomez-Manjarres, Diana C.; Ruminski, Caroline; DiMarco, John P.; Lake, Douglas E.

2017-01-01

Objective: To determine the association of new-onset atrial fibrillation with outcomes, including ICU length of stay and survival. Design: Retrospective cohort of ICU admissions. We found atrial fibrillation using automated detection (≥ 90 s in 30 min) and classed as new-onset if there was no prior diagnosis of atrial fibrillation. We identified determinants of new-onset atrial fibrillation and, using propensity matching, characterized its impact on outcomes. Setting: Tertiary care academic center. Patients: A total of 8,356 consecutive adult admissions to either the medical or surgical/trauma/burn ICU with available continuous electrocardiogram data. Interventions: None. Measurements and Main Results: From 74 patient-years of every 15-minute observations, we detected atrial fibrillation in 1,610 admissions (19%), with median burden less than 2%. Most atrial fibrillation was paroxysmal; less than 2% of admissions were always in atrial fibrillation. New-onset atrial fibrillation was subclinical or went undocumented in 626, or 8% of all ICU admissions. Advanced age, acute respiratory failure, and sepsis were the strongest predictors of new-onset atrial fibrillation. In propensity-adjusted regression analyses, clinical new-onset atrial fibrillation was associated with increased hospital mortality (odds ratio, 1.63; 95% CI, 1.01–2.63) and longer length of stay (2.25 d; CI, 0.58–3.92). New-onset atrial fibrillation was not associated with survival after hospital discharge (hazard ratio, 0.99; 95% CI, 0.76–1.28 and hazard ratio, 1.11; 95% CI, 0.67–1.83, respectively, for subclinical and clinical new-onset atrial fibrillation). Conclusions: Automated analysis of continuous electrocardiogram heart rate dynamics detects new-onset atrial fibrillation in many ICU patients. Though often transient and frequently unrecognized, new-onset atrial fibrillation is associated with poor hospital outcomes. PMID:28296811

Cold denaturation of α-synuclein amyloid fibrils.

PubMed

Ikenoue, Tatsuya; Lee, Young-Ho; Kardos, József; Saiki, Miyu; Yagi, Hisashi; Kawata, Yasushi; Goto, Yuji

2014-07-21

Although amyloid fibrils are associated with numerous pathologies, their conformational stability remains largely unclear. Herein, we probe the thermal stability of various amyloid fibrils. α-Synuclein fibrils cold-denatured to monomers at 0-20 °C and heat-denatured at 60-110 °C. Meanwhile, the fibrils of β2-microglobulin, Alzheimer's Aβ1-40/Aβ1-42 peptides, and insulin exhibited only heat denaturation, although they showed a decrease in stability at low temperature. A comparison of structural parameters with positive enthalpy and heat capacity changes which showed opposite signs to protein folding suggested that the burial of charged residues in fibril cores contributed to the cold denaturation of α-synuclein fibrils. We propose that although cold-denaturation is common to both native proteins and misfolded fibrillar states, the main-chain dominated amyloid structures may explain amyloid-specific cold denaturation arising from the unfavorable burial of charged side-chains in fibril cores. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lone atrial fibrillation associated with creatine monohydrate supplementation.

PubMed

Kammer, Ryan T

2005-05-01

Atrial fibrillation in young patients without structural heart disease is rare. Therefore, when the arrhythmia is present in this population, reversible causes must be identified and resolved. Thyroid disorders, illicit drug or stimulant use, and acute alcohol intoxication are among these causes. We report the case of a 30-year-old Caucasian man who came to the emergency department in atrial fibrillation with rapid ventricular response. His medical history was unremarkable, except for minor fractures of the fingers and foot. Thyroid-stimulating hormone, magnesium, and potassium levels were within normal limits, urine drug screen was negative, and alcohol use was denied. However, when the patient was questioned about use of herbal products and supplements, the use of creatine monohydrate was revealed. The patient was admitted to the hospital, anticoagulated with unfractionated heparin, and given intravenous diltiazem for rate control and intravenous amiodarone for rate and rhythm control. When discharged less than 24 hours later, he was receiving metoprolol and aspirin, with follow-up plans for echocardiography and nuclear imaging to assess perfusion. Exogenous creatine is used by athletes to theoretically improve exercise performance. Vegetarians may also take creatine to replace what they are not consuming from meat, fish, and other animal products. Previous anecdotal reports have linked creatine to the development of arrhythmia. Clinicians must be diligent when interviewing patients about their drug therapy histories and include questions about their use of herbal products and dietary supplements. In addition, it is important to report adverse effects associated with frequently consumed supplements and herbal products to the Food and Drug Administration and in the literature.

Viscoelastic behavior of discrete human collagen fibrils.

PubMed

Svensson, René B; Hassenkam, Tue; Hansen, Philip; Peter Magnusson, S

2010-01-01

Whole tendon and fibril bundles display viscoelastic behavior, but to the best of our knowledge this property has not been directly measured in single human tendon fibrils. In the present work an atomic force microscopy (AFM) approach was used for tensile testing of two human patellar tendon fibrils. Fibrils were obtained from intact human fascicles, without any pre-treatment besides frozen storage. In the dry state a single isolated fibril was anchored to a substrate using epoxy glue, and the end of the fibril was glued on to an AFM cantilever for tensile testing. In phosphate buffered saline, cyclic testing was performed in the pre-yield region at different strain rates, and the elastic response was determined by a stepwise stress relaxation test. The elastic stress-strain response corresponded to a second-order polynomial fit, while the viscous response showed a linear dependence on the strain. The slope of the viscous response showed a strain rate dependence corresponding to a power function of powers 0.242 and 0.168 for the two patellar tendon fibrils, respectively. In conclusion, the present work provides direct evidence of viscoelastic behavior at the single fibril level, which has not been previously measured.

NBD-labelled phospholipid accelerates apolipoprotein C-II amyloid fibril formation but is not incorporated into mature fibrils

PubMed Central

Ryan, Timothy M.; Griffin, Michael D. W.; Bailey, Michael F.; Schuck, Peter; Howlett, Geoffrey J.

2014-01-01

Human apolipoprotein (apo) C-II is one of several lipid-binding proteins that self-assemble into fibrils and accumulate in disease-related amyloid deposits. A general characteristic of these amyloid deposits is the presence of lipids, known to modulate individual steps in amyloid fibril formation. ApoC-II fibril formation is activated by sub-micellar phospholipids but inhibited by micellar lipids. We examined the mechanism for the activation by sub-micellar lipids using the fluorescently-labelled, short-chain phospholipid, 1-dodecyl-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]-2-hydroxy-glycero-3-phosphocholine (NBD-lyso-12-PC). Addition of submicellar NBD-lyso-12-PC increased the rate of fibril formation by apoC-II approximately two-fold. Stopped flow kinetic analysis using fluorescence detection and low, non-fibril forming concentrations of apoC-II indicated NBD-Lyso-12-PC binds rapidly, in the millisecond timescale, followed by the slower formation of discrete apoC-II tetramers. Sedimentation velocity analysis showed NBD-Lyso-12-PC binds to both apoC-II monomers and tetramers at approximately 5 sites per monomer with an average dissociation constant of approximately 10 μM. Mature apoC-II fibrils formed in the presence of NBD-Lyso-12-PC were devoid of lipid indicating a purely catalytic role for sub-micellar lipids in the activation of apoC-II fibril formation. These studies demonstrate the catalytic potential of small amphiphilic molecules to control protein folding and fibril assembly pathways. PMID:21985034

Serum Bilirubin Concentration is Associated with Left Ventricular Remodeling in Patients with Type 2 Diabetes Mellitus: A Cohort Study.

PubMed

Inoue, Tomoaki; Sonoda, Noriyuki; Hiramatsu, Shinsuke; Kimura, Shinichiro; Ogawa, Yoshihiro; Inoguchi, Toyoshi

2018-02-01

Previous studies have shown that serum bilirubin concentration is inversely associated with the risk of cardiovascular disease. The relationship between serum bilirubin concentration and left ventricular geometry, however, has not been investigated in patients with diabetes mellitus. In this cohort study, 158 asymptomatic patients with type 2 diabetes mellitus without overt heart disease were enrolled. Left ventricular structure and function were assessed using echocardiography. Serum bilirubin concentration, glycemic control, lipid profile, and other clinical characteristics were evaluated, and their association with left ventricular geometry was determined. Patients with New York Heart Association Functional Classification greater than I, left ventricular ejection fraction less than 50%, history of coronary artery disease, severe valvulopathy, chronic atrial fibrillation, or creatinine clearance less than 30 ml/min, and those receiving insulin treatment, were excluded. Univariate analyses showed that relative wall thickness (RWT) was significantly correlated with diastolic blood pressure (P = 0.003), HbA1c (P = 0.024), total cholesterol (P = 0.043), urinary albumin (P = 0.023), and serum bilirubin concentration (P = 0.009). There was no association between left ventricular mass index and serum bilirubin concentration. Multivariate linear regression analysis showed that log RWT was positively correlated with diastolic blood pressure (P = 0.010) and that log RWT was inversely correlated with log bilirubin (P = 0.003). In addition, the patients with bilirubin less than 0.8 mg/dl had a higher prevalence of concentric left ventricular remodeling compared with those with bilirubin 0.8 mg/dl or more. Our study shows that the serum bilirubin concentration may be associated with the progression of concentric left ventricular remodeling in patients with type 2 diabetes mellitus.

Prevalence of atrial arrhythmias in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

PubMed

Camm, Christian F; James, Cynthia A; Tichnell, Crystal; Murray, Brittney; Bhonsale, Aditya; te Riele, Anneline S J M; Judge, Daniel P; Tandri, Harikrishna; Calkins, Hugh

2013-11-01

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited cardiomyopathy, characterized by right ventricular dysfunction and ventricular arrhythmias. Limited information is available concerning atrial arrhythmias in ARVD/C. The purpose of this study was to characterize spontaneous atrial arrhythmias in a large registry population of ARVD/C patients. Patients (n = 248) from the Johns Hopkins ARVD/C registry who met the diagnostic criteria and had undertaken genotype analysis were included. Medical records of each were reviewed to ascertain incidence and characteristics of atrial arrhythmia episodes. Detailed demographic, phenotypic, and structural information was obtained from registry data. Thirty-five patients with ARVD/C (14%) experienced one or more types of atrial arrhythmia during median follow-up of 5.78 (interquartile range 8.52) years. Atrial fibrillation was the most common atrial arrhythmia, occurring in 80% of ARVD/C patients with atrial arrhythmias. Patients developed atrial arrhythmias at a mean age of 43.0 ± 14.0 years. Atrial arrhythmia patients obtained a total of 22 inappropriate implantable cardioverter-defibrillator shocks during follow-up. Older age at last follow-up (P <.001) and male gender (P = .044) were associated with atrial arrhythmia development. Patients with atrial arrhythmias had a higher occurrence of death (P = .028), heart failure (P <.001), and left atrial enlargement on echocardiography (P = .004). Atrial arrhythmias are common in ARVD/C and present at a younger age than in the general population. They are associated with male gender, increasing age, and left atrial enlargement. Atrial arrhythmias are clinically important as they are associated with inappropriate implantable cardioverter-defibrillator shocks and increased risk of both death and heart failure. © 2013 Heart Rhythm Society. All rights reserved.

Erroneous Magnet Positioning Leads to Failure of Inhibition of Inappropriate Shock during Fast Conducting Atrial Fibrillation Episodes.

PubMed

Römers, Hans; VAN Dijk, Vincent; Balt, Jippe

2017-06-01

We present the case of a 75-year-old patient with a single-chamber St. Jude Medical internal cardioverter defibrillator (ICD; St. Jude Medical, St. Paul, MN, USA) for primary prevention, who was admitted with 39 inappropriate ICD shocks because of atrial fibrillation with rapid ventricular frequention, despite magnet placement. Review of the device manual and literature revealed that apart from different responses to magnet placement programmed for the various manufacturers, the type of magnet and the positioning can be of specific interest. In the case presented, the donut-shaped magnet should have been placed off-center instead of directly over the device. © 2017 Wiley Periodicals, Inc.

Does permanent atrial fibrillation modify response to cardiac resynchronization therapy in heart failure patients?

PubMed

Abreu, Ana; Oliveira, Mário; Silva Cunha, Pedro; Santa Clara, Helena; Portugal, Guilherme; Gonçalves Rodrigues, Inês; Santos, Vanessa; Morais, Luís; Selas, Mafalda; Soares, Rui; Branco, Luísa; Ferreira, Rui; Mota Carmo, Miguel

2017-10-01

The benefits of cardiac resynchronization therapy (CRT) documented in heart failure (HF) may be influenced by atrial fibrillation (AF). We aimed to compare CRT response in patients in AF and in sinus rhythm (SR). We prospectively studied 101 HF patients treated by CRT. Rates of clinical, echocardiographic and functional response, baseline NYHA class and variation, left ventricular ejection fraction, volumes and mass, atrial volumes, cardiopulmonary exercise test (CPET) duration (CPET dur), peak oxygen consumption (VO 2 max) and ventilatory efficiency (VE/VCO 2 slope) were compared between AF and SR patients, before and at three and six months after implantation of a CRT device. All patients achieved ≥95% biventricular pacing, and 5.7% underwent atrioventricular junction ablation. Patients were divided into AF (n=35) and SR (n=66) groups; AF patients were older, with larger atrial volumes and lower CPET dur and VO 2 max before CRT. The percentages of clinical and echocardiographic responders were similar in the two groups, but there were more functional responders in the AF group (71% vs. 39% in SR patients; p=0.012). In SR patients, left atrial volume and left ventricular mass were significantly reduced (p=0.015 and p=0.021, respectively), whereas in AF patients, CPET dur (p=0.003) and VO 2 max (p=0.001; 0.083 age-adjusted) showed larger increases. Clinical and echocardiographic response rates were similar in SR and AF patients, with a better functional response in AF. Improvement in left ventricular function and volumes occurred in both groups, but left ventricular mass reduction and left atrial reverse remodeling were seen exclusively in SR patients (ClinicalTrials.gov identifier: NCT02413151; FCT code: PTDC/DES/120249/2010). Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Tpeak - Tend and Tpeak - Tend /QT ratio as markers of ventricular arrhythmia risk in cardiac resynchronization therapy patients.

PubMed

Barbhaiya, Chirag; Po, Jose Ricardo F; Hanon, Sam; Schweitzer, Paul

2013-01-01

Cardiac resynchronization therapy (CRT) increases transmural dispersion of repolarization (TDR) and can be pro-arrhythmic. However, overall arrhythmia risk was not increased in large-scale CRT clinical trials. Increased TDR as measured by T(peak ) -T(end) (TpTe) was associated with arrhythmia risk in CRT in a single-center study. This study investigates whether QT interval, TpTe, and TpTe/QT ratio are associated with ventricular arrhythmias in patients with CRT-defibrillator (CRT-D). Post-CRT-D implant electrocardiograms of 128 patients (age 71.3 years ± 10.3) with at least 2 months of follow-up at our institution's device clinic (mean follow-up of 28.5 months ± 17) were analyzed for QT interval, TpTe, and TpTe/QT ratio. Incidence of ventricular arrhythmias was determined based on routine and directed device interrogations. Appropriate implantable cardioverter-defibrillator therapy for sustained ventricular tachycardia or ventricular fibrillation was delivered in 18 patients (14%), and nonsustained ventricular tachycardia (NSVT) was detected but did not require therapy in 58 patients (45%). Patients who received appropriate defibrillator therapy had increased TpTe/QT ratio (0.24 ± 0.03 ms vs 0.20 ± 0.04, P = 0.0002) and increased TpTe (105.56 ± 20.36 vs 87.82 ± 22.32 ms, P = 0.002), and patients with NSVT had increased TpTe/QT ratio (0.22 ± 0.04 vs 0.20 ± 0.04, P = 0.016). Increased QT interval was not associated with risk of ventricular arrhythmia. The relative risk for appropriate defibrillator therapy of T(p) T(e) /QT ratio ≥ 0.25 was 3.24 (P = 0.016). Increased TpTe and increased TpTe/QT ratio are associated with increased incidence of ventricular arrhythmias in CRT-D. The utility of TpTe interval and TpTe/QT ratio as potentially modifiable risk factors for ventricular arrhythmias in CRT requires further study. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

Surgical ablation of ventricular tachycardia secondary to congenital ventricular septal aneurysm.

PubMed

Graffigna, A; Minzioni, G; Ressia, L; Vigano, M

1994-04-01

Three patients underwent surgical ablation for ventricular tachycardia resulting from an aneurysm of the membranous portion of the ventricular septum. Two patients had a definite history of cardiac murmur during infancy, and one of them was found at the time of operation to have a left-to-right shunt through the apex of the aneurysm. The earliest ventricular activation sites were located around the neck of the aneurysm and were ablated in 1 patient by encircling the endocardial ventriculotomy and by cryoablation in the remaining 2. After focus resection had been completed, aneurysm resection and ventricular septal reconstruction were performed. All patients were alive and free of ventricular tachycardia and did not need medication as of 61, 66, and 88 months postoperatively. Spontaneous closure of a ventricular septal defect may lead to the formation of an aneurysm in the ventricular septum that may sustain ventricular tachycardias. Such arrhythmias can be effectively treated using electrically guided surgical techniques.

Molecular basis for insulin fibril assembly

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

Ivanova, Magdalena I.; Sievers, Stuart A.; Sawaya, Michael R.

2009-12-01

In the rare medical condition termed injection amyloidosis, extracellular fibrils of insulin are observed. We found that the segment of the insulin B-chain with sequence LVEALYL is the smallest segment that both nucleates and inhibits the fibrillation of full-length insulin in a molar ratio-dependent manner, suggesting that this segment is central to the cross-{beta} spine of the insulin fibril. In isolation from the rest of the protein, LVEALYL forms microcrystalline aggregates with fibrillar morphology, the structure of which we determined to 1 {angstrom} resolution. The LVEALYL segments are stacked into pairs of tightly interdigitated {beta}-sheets, each pair displaying the drymore » steric zipper interface typical of amyloid-like fibrils. This structure leads to a model for fibrils of human insulin consistent with electron microscopic, x-ray fiber diffraction, and biochemical studies.« less

Association of Burden of Atrial Fibrillation With Risk of Ischemic Stroke in Adults With Paroxysmal Atrial Fibrillation: The KP-RHYTHM Study.

PubMed

Go, Alan S; Reynolds, Kristi; Yang, Jingrong; Gupta, Nigel; Lenane, Judith; Sung, Sue Hee; Harrison, Teresa N; Liu, Taylor I; Solomon, Matthew D

2018-05-16

Atrial fibrillation is a potent risk factor for stroke, but whether the burden of atrial fibrillation in patients with paroxysmal atrial fibrillation independently influences the risk of thromboembolism remains controversial. To determine if the burden of atrial fibrillation characterized using noninvasive, continuous ambulatory monitoring is associated with the risk of ischemic stroke or arterial thromboembolism in adults with paroxysmal atrial fibrillation. This retrospective cohort study conducted from October 2011 and October 2016 at 2 large integrated health care delivery systems used an extended continuous cardiac monitoring system to identify adults who were found to have paroxysmal atrial fibrillation on 14-day continuous ambulatory electrocardiographic monitoring. The burden of atrial fibrillation was defined as the percentage of analyzable wear time in atrial fibrillation or flutter during the up to 14-day monitoring period. Ischemic stroke and other arterial thromboembolic events occurring while patients were not taking anticoagulation were identified through November 2016 using electronic medical records and were validated by manual review. We evaluated the association of the burden of atrial fibrillation with thromboembolism while not taking anticoagulation after adjusting for the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) or CHA2DS2-VASc stroke risk scores. Among 1965 adults with paroxysmal atrial fibrillation, the mean (SD) age was 69 (11.8) years, 880 (45%) were women, 496 (25%) were persons of color, the median ATRIA stroke risk score was 4 (interquartile range [IQR], 2-7), and the median CHA2DS2-VASc score was 3 (IQR, 1-4). The median burden of atrial fibrillation was 4.4% (IQR ,1.1%-17.23%). Patients with a higher burden of atrial fibrillation were less likely to be women or of Hispanic ethnicity, but had more prior cardioversion attempts compared with those who had a lower burden. After adjusting for either ATRIA or CHA2DS2

Magnetite nanoparticle interactions with insulin amyloid fibrils

NASA Astrophysics Data System (ADS)

Chen, Yun-Wen; Chang, Chiung-Wen; Hung, Huey-Shan; Kung, Mei-Lang; Yeh, Bi-Wen; Hsieh, Shuchen

2016-10-01

Accumulation of amyloid fibrils is one of the likely key factors leading to the development of Alzheimer’s disease and other amyloidosis associated diseases. Magnetic nanoparticles (NPs) have been developed as promising medical materials for many medical applications. In this study, we have explored the effects of Fe3O4 NPs on the fibrillogenesis process of insulin fibrils. When Fe3O4 NPs were co-incubated with insulin, Fe3O4 NPs had no effect on the structural transformation into amyloid-like fibrils but had higher affinity toward insulin fibrils. We demonstrated that the zeta potential of insulin fibrils and Fe3O4 NPs were both positive, suggesting the binding forces between Fe3O4 NPs and insulin fibrils were van der Waals forces but not surface charge. Moreover, a different amount of Fe3O4 NPs added had no effect on secondary structural changes of insulin fibrils. These results propose the potential use of Fe3O4 NPs as therapeutic agents against diseases related to protein aggregation or contrast agents for magnetic resonance imaging.

Ambulatory ECG monitoring in atrial fibrillation management.

PubMed

Rosero, Spencer Z; Kutyifa, Valentina; Olshansky, Brian; Zareba, Wojciech

2013-01-01

Ambulatory ECG monitoring technology has rapidly evolved over the last few decades and has been shown to identify life-threatening and non-life threatening arrhythmias and provide actionable data to guide clinical decision making. Atrial fibrillation episodes can often be asymptomatic, even after catheter ablation for atrial fibrillation, creating a disconnect between symptoms and actual arrhythmia burden which may alter clinical management. In this review, we aim to provide a comprehensive overview of invasive and non-invasive ECG monitoring strategies in patients with atrial fibrillation, with a special focus on the diagnosis of atrial fibrillation, and on follow-up of patients after catheter ablation for atrial fibrillation ablation. © 2013.

First use of an untethered, vented electric left ventricular assist device for long-term support.

PubMed

Frazier, O H

1994-06-01

This report describes the first long-term (505-day) application of the vented electric (VE) HeartMate left ventricular assist device (LVAD) (Thermo Cardiosystems, Inc). The device consists of an abdominally placed, battery-powered titanium blood pump that, in contrast to earlier pneumatically powered systems, allows patients untethered freedom of movement. The batteries last 5 to 8 hours and can be changed on a rotating basis indefinitely. The patient, a 33-year-old man (90 kg, blood type O) with idiopathic cardiomyopathy, experienced end-organ heart failure (New York Heart Association [NYHA] class IV) while he was awaiting heart transplantation. When his hemodynamic criteria met those outlined in the protocol, we implanted the VE-LVAD as a bridge to transplantation. The patient was supported by the device for more than 16 months. His cardiac status returned to NYHA class I, and he was eventually allowed to take day trips outside the hospital as he awaited transplantation. The VE-LVAD enabled the patient to participate in activities such as eating in restaurants, going to movies, and practicing basketball shots. Unfortunately, the patient died suddenly due to a neurological thromboembolic event that occurred on day 503 of VE-LVAD support. The VE-LVAD improved native left ventricular function by chronic unloading, and ventricular remodeling resulted in a more normal configuration anatomically, physiologically, and ultimately, histologically and pathologically.

Vitamin D and new-onset atrial fibrillation: A meta-analysis of randomized controlled trials.

PubMed

Huang, Wei-Ling; Yang, Jun; Yang, Jian; Wang, Hui-Bo; Yang, Chao-Jun; Yang, Ying

2017-11-14

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, which affects 1.5% to 2% of the general population. More than six million Europeans suffer from AF. To research vitamin D levels in the prevention of new-onset atrial fibrillation (AF), we conducted a systematic review of randomized controlled trials (RCTs). We focused on the vitamin D levels in the prevention of new-onset AF. The outcomes assessed were vitamin D levels, left ventricular ejection fraction (LVEF), and left atrium diameter. Six RCTs ultimately met the inclusion criteria in the meta-analysis. The outcomes of Vitamin D levels (MD = -4.27, 95% CI = -5.20 to-3.34, P = 0.30) in the new-onset AF showed no significant difference. The left atrium diameter (MD = 1.96, 95% CI = 1.48 to 2.60, P < 0.01) between new-onset AF and LVEF (MD = -0.92, 95% CI = -1.59 to -0.26, P < 0.01) showed significant difference. Our study shows that circulating vitamin D levels may not play a major role in the development of new-onset AF. Copyright © 2017 Hellenic Society of Cardiology. Published by Elsevier B.V. All rights reserved.

I(f) current inhibitor ivabradine in patients with idiopathic dilated cardiomyopathy: Impact on the exercise tolerance and quality of life.

PubMed

Abdel-Salam, Zainab; Rayan, Mona; Saleh, Ayman; Abdel-Barr, Mohamed G; Hussain, Mohamed; Nammas, Wail

2015-01-01

Evidence supported a beneficial effect of ivabradine on clinical outcome of patients with systolic heart failure, and a sinus heart rate (HR) ≥ 70 bpm. We explored the effect of ivabradine, vs. placebo, added to evidence-based treatment on exercise tolerance and quality of life in patients with idiopathic dilated cardiomyopathy. We enrolled 43 consecutive patients with dilated cardiomyopathy of no apparent cause, a left ventricular ejection fraction (LVEF) < 40%, New York Heart Association class ≥ II, sinus HR ≥ 70 bpm, and background evidence-based anti-failure medications. Ischemic heart disease was ruled out. Patients were randomized (1:1) to receive ivabradine or placebo. Ivabradine was titrated up gradually till 7.5 mg twice daily, or a HR < 60 bpm, and continued for 3 months. Symptom-limited exercise tolerance test was performed, and quality of life was assessed by the Minnesota Living With Heart Failure Questionnaire at 0, and 3 months. Forty-three patients were randomized to ivabradine (n = 20), or placebo (n = 23). Mean age was 50.8 ± 14.5 years (53.5% males). Mean HR was 85 ± 12 bpm, and mean LVEF was 32 ± 6%. Mean dose of carvedilol was 31.2% of the target dose. Baseline HR, blood pressure, exercise tolerance, Minnesota questionnaire score, and left ventricular systolic function were comparable between the two groups (p > 0.05 for all). At 3 months, mean dose of ivabradine was 6.8 mg bid. Ivabradine-treated patients had a lower HR, and improved left ventricular dimensions and systolic function, versus placebo-treated ones (p < 0.05 for all). HR dropped by a mean of 14 bpm in the ivabradine group, corrected for placebo. Both exercise tolerance, and Minnesota questionnaire score were better in the ivabradine group (p < 0.05 both). Ivabradine was well-tolerated. In symptomatic patients with idiopathic dilated cardiomyopathy, the addition of ivabradine, vs. placebo, to evidence-based treatment, reduced HR, and improved functional capacity, at short

Micromechanical testing of individual collagen fibrils.

PubMed

van der Rijt, Joost A J; van der Werf, Kees O; Bennink, Martin L; Dijkstra, Pieter J; Feijen, Jan

2006-09-15

A novel method based on AFM was used to attach individual collagen fibrils between a glass surface and the AFM tip, to allow force spectroscopy studies of these. The fibrils were deposited on glass substrates that are partly coated with Teflon AF. A modified AFM tip was used to accurately deposit epoxy glue droplets on either end of the collagen fibril that cross the glass-Teflon AF interface, as to such attach it with one end to the glass and the other end to the AFM tip. Single collagen fibrils have been mechanically tested in ambient conditions and were found to behave reversibly up to stresses of 90 MPa. Within this regime a Young's modulus of 2-7 GPa was obtained. In aqueous media, the collagen fibrils could be tested reversibly up to about 15 MPa, revealing Young's moduli ranging from 0.2 to at most 0.8 GPa.

Idiopathic normal pressure hydrocephalus: theoretical concept of a spinal etiology.

PubMed

Hamlat, Abderrahmane; Abderrahmane, Hamlat; Sid-Ahmed, Seddik; Seddik, Sid-Ahmed; Adn, Mahmoudreza; Mahmoudreza, Adn; Askar, Brahim; Brahim, Askar; Pasqualini, Edouardo; Edouardo, Pasqualini

2006-01-01

Normal pressure hydrocephalus (NPH) is an adult syndrome characterised by a combination of gait disturbance, varying degrees of cognitive decline, urinary incontinence, ventricular enlargement and normal mean intracranial pressure. Since this syndrome was first described, its pathophysiology has been a matter of great debate, although it is now considered that NPH could be divided into two groups: cases with unknown etiology (idiopathic normal pressure hydrocephalus, or INPH) and those which develop from several known causes (such as trauma, meningitis or subarachnoid haemorrhage). The pathophysiology of INPH is still unclear and a matter of debate. In this manuscript, the current pathophysiological conditions of INPH are analysed and the authors put forward the theory that the disease is a dynamic syndrome which occurs in patients who have suffered a significant loss of spinal compliance over time. Consequently, intracranial pressure increases more during systole in INPH patients because it cannot be compensated for by the escape of CSF into the spinal canal as effectively, due to the reduced volume or lack of distension of the spinal canal. This leads to an increase in ventricular size and causes cumulative brain damage over a long period of time and accounts for the slow, progressive nature of NPH. The loss of spinal compliance with age is fundamental to the proposed theory which provides a theoretical justification for studying the spinal canal in INPH and investigating the relationship between the progressive narrowing of the spinal canal and the compensating ability of the craniospinal system.

Impact of stepwise ablation on the biatrial substrate in patients with persistent atrial fibrillation and heart failure.

PubMed

Jones, David G; Haldar, Shouvik K; Jarman, Julian W E; Johar, Sofian; Hussain, Wajid; Markides, Vias; Wong, Tom

2013-08-01

Ablation of persistent atrial fibrillation can be challenging, often involving not only pulmonary vein isolation (PVI) but also additional linear lesions and ablation of complex fractionated electrograms (CFE). We examined the impact of stepwise ablation on a human model of advanced atrial substrate of persistent atrial fibrillation in heart failure. In 30 patients with persistent atrial fibrillation and left ventricular ejection fraction ≤35%, high-density CFE maps were recorded biatrially at baseline, in the left atrium (LA) after PVI and linear lesions (roof and mitral isthmus), and biatrially after LA CFE ablation. Surface area of CFE (mean cycle length ≤120 ms) remote to PVI and linear lesions, defined as CFE area, was reduced after PVI (18.3±12.03 to 10.2±7.1 cm(2); P<0.001) and again after linear lesions (7.7±6.5 cm(2); P=0.006). Complete mitral isthmus block predicted greater CFE reduction (P=0.02). Right atrial CFE area was reduced by LA ablation, from 25.9±14.1 to 12.9±11.8 cm(2) (P<0.001). Estimated 1-year arrhythmia-free survival was 72% after a single procedure. Incomplete linear lesion block was an independent predictor of arrhythmia recurrence (hazard ratio, 4.69; 95% confidence interval, 1.05-21.06; P=0.04). Remote LA CFE area was progressively reduced following PVI and linear lesions, and LA ablation reduced right atrial CFE area. Reduction of CFE area at sites remote from ablation would suggest either regression of the advanced atrial substrate or that these CFE were functional phenomena. Nevertheless, in an advanced atrial fibrillation substrate, linear lesions after PVI diminished the target area for CFE ablation, and complete lesions resulted in a favorable clinical outcome.

Laser-induced propagation and destruction of amyloid beta fibrils.

PubMed

Yagi, Hisashi; Ozawa, Daisaku; Sakurai, Kazumasa; Kawakami, Toru; Kuyama, Hiroki; Nishimura, Osamu; Shimanouchi, Toshinori; Kuboi, Ryoichi; Naiki, Hironobu; Goto, Yuji

2010-06-18

The amyloid deposition of amyloid beta (Abeta) peptides is a critical pathological event in Alzheimer disease (AD). Preventing the formation of amyloid deposits and removing preformed fibrils in tissues are important therapeutic strategies against AD. Previously, we reported the destruction of amyloid fibrils of beta(2)-microglobulin K3 fragments by laser irradiation coupled with the binding of amyloid-specific thioflavin T. Here, we studied the effects of a laser beam on Abeta fibrils. As was the case for K3 fibrils, extensive irradiation destroyed the preformed Abeta fibrils. However, irradiation during spontaneous fibril formation resulted in only the partial destruction of growing fibrils and a subsequent explosive propagation of fibrils. The explosive propagation was caused by an increase in the number of active ends due to breakage. The results not only reveal a case of fragmentation-induced propagation of fibrils but also provide insights into therapeutic strategies for AD.

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

Failure to Treat Life-Threatening Ventricular Tachyarrhythmias in Contemporary Implantable Cardioverter–Defibrillators

PubMed Central

Thøgersen, Anna Margrethe; Larsen, Jacob Moesgaard; Johansen, Jens Brock; Abedin, Moeen

2017-01-01

Background: In clinical trials, manufacturer-specific, strategic programming of implantable cardioverter–defibrillators (ICDs), including faster detection rates, reduces unnecessary therapy but permits therapy for ventricular tachycardia/ventricular fibrillation (VF). Present consensus recommends a generic rate threshold between 185 and 200 beats per minute, which exceeds the rate tested in clinical trials for some manufacturers. In a case series, we sought to determine the relationship between programmed parameters and failure of modern ICDs to treat VF. Methods and Results: We reviewed cases in which normally functioning ICDs failed to deliver timely therapy for VF from April 2015 to January 2017 at 4 institutions. Of 10 ambulatory patients, 5 died from untreated VF, 4 had cardiac arrests requiring external shocks, and 1 was rescued by a delayed ICD shock. VF did not satisfy programmed detection criteria in 9 patients (90%). Seven of these patients had slowest detection rates that were consistent with generic recommendations but not tested in a peer-reviewed trial for their manufacturer’s ICDs. Manufacturer-specific factors interacted with fast detection rates to withhold therapy, including strict VF episode termination rules, enhancements to minimize T-wave oversensing, and features that restrict therapy to regular rhythms in ventricular tachycardia zones. Untreated VF despite recommended programming accounted for 56% of sudden deaths and 11% of all deaths during the study period. Conclusions: Complex and unanticipated interactions between manufacturer-specific features and generic programming can prevent therapy for VF. More data are needed to assess the risks and benefits of translating evidence-based detection parameters from one manufacturer to another. PMID:28916511

Integration of intracardiac echocardiography and computed tomography during atrial fibrillation ablation: Combining ultrasound contours obtained from the right atrium and ventricular outflow tract.

PubMed

Nakamura, Kohki; Naito, Shigeto; Kaseno, Kenichi; Nakatani, Yosuke; Sasaki, Takehito; Anjo, Naofumi; Yamashita, Eiji; Kumagai, Koji; Funabashi, Nobusada; Kobayashi, Yoshio; Oshima, Shigeru

2017-02-01

We aimed to optimize the acquisition of the left atrial (LA) and pulmonary vein (PV) ultrasound contours for more accurate integration of intracardiac echocardiography (ICE) and computed tomography (CT) using the CARTO ® 3 system during atrial fibrillation (AF) ablation. Eighty-five AF patients underwent integration of ICE and CT using (1) the LA roof and posterior wall contours acquired from the right atrium (RA), (2) all LA/PV contours from the RA (Whole-RA-integration), (3) the LA roof/posterior wall contours from the RA and right ventricular outflow tract (RVOT) (Posterior-RA/RV-integration), and (4) all LA/PV contours from the RA and RVOT (Whole-RA/RV-integration). The integration accuracy was compared using the (1) surface registration error, (2) distances between the three-dimensional CT and eight specific sites on the anterior, posterior, superior, and inferior aspects of the right and left circumferential PV isolation lines, and (3) registration score: a score of 0 or 1 was assigned for whether or not each specific site was visually aligned with the CT, and summed for each method (0 best, 8 worst). Posterior-RA/RV-integration revealed a significantly lower surface registration error (1.30±0.15mm) than Whole-RA- and Whole-RA/RV-integration (p<0.001). The mean distances of the eight specific sites and the registration score for Posterior-RA/RV-integration (median 1.26mm and 2, respectively) were significantly smaller than those for the other integration approaches (p<0.001). Image integration with the LA roof and posterior wall contours acquired from the RA and RVOT may provide greater accuracy for catheter navigation with three-dimensional CT during AF ablation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Long-term survival in patients undergoing cardiac resynchronization therapy: the importance of performing atrio-ventricular junction ablation in patients with permanent atrial fibrillation

PubMed Central

Gasparini, Maurizio; Auricchio, Angelo; Metra, Marco; Regoli, François; Fantoni, Cecilia; Lamp, Barbara; Curnis, Antonio; Vogt, Juergen; Klersy, Catherine

2008-01-01

Aims To investigate the effects of cardiac resynchronization therapy (CRT) on survival in heart failure (HF) patients with permanent atrial fibrillation (AF) and the role of atrio-ventricular junction (AVJ) ablation in these patients. Methods and results Data from 1285 consecutive patients implanted with CRT devices are presented: 1042 patients were in sinus rhythm (SR) and 243 (19%) in AF. Rate control in AF was achieved by either ablating the AVJ in 118 patients (AVJ-abl) or prescribing negative chronotropic drugs (AF-Drugs). Compared with SR, patients with AF were significantly older, more likely to be non-ischaemic, with higher ejection fraction, shorter QRS duration, and less often received ICD back-up. During a median follow-up of 34 months, 170/1042 patients in SR and 39/243 in AF died (mortality: 8.4 and 8.9 per 100 person-year, respectively). Adjusted hazard ratios were similar for all-cause and cardiac mortality [0.9 (0.57–1.42), P = 0.64 and 1.00 (0.60–1.66) P = 0.99, respectively]. Among AF patients, only 11/118 AVJ-abl patients died vs. 28/125 AF-Drugs patients (mortality: 4.3 and 15.2 per 100 person-year, respectively, P < 0.001). Adjusted hazard ratios of AVJ-abl vs. AF-Drugs was 0.26 [95% confidence interval (CI) 0.09–0.73, P = 0.010] for all-cause mortality, 0.31 (95% CI 0.10–0.99, P = 0.048) for cardiac mortality, and 0.15 (95% CI 0.03–0.70, P = 0.016) for HF mortality. Conclusion Patients with HF and AF treated with CRT have similar mortality compared with patients in SR. In AF, AVJ ablation in addition to CRT significantly improves overall survival compared with CRT alone, primarily by reducing HF death. PMID:18390869

Safety considerations in the pharmacological management of atrial fibrillation.

PubMed

Camm, A John

2008-07-21

The pharmacological management of atrial fibrillation (AF) requires careful consideration from a safety perspective. This article focuses primarily on maintenance therapy using antiarrhythmic drugs (AADs). The foremost safety issue for AADs is the propensity of class IA and III agents to cause torsade de pointes arrhythmias. Class IA drugs, particularly quinidine, can induce torsade de pointes at low or subtherapeutic doses, but higher doses are not necessarily associated with an increased incidence. 'Pure' class III drugs such as dofetilide induce torsade de pointes in a dose-related manner, but some class III agents with more complex actions such as amiodarone have a markedly lower potential to cause this arrhythmia. The risk of torsade de pointes precludes the use of class IA and 'pure' class III agents in patients with left ventricular hypertrophy and bradycardia. Class IC agents may cause sustained monomorphic ventricular tachycardias and are generally precluded in ischaemic and structural heart disease. Advanced heart failure patients may be treated with amiodarone or dofetilide, but most other AADs are unsuitable. The most important extracardiac toxicities occurring with AADs are those of amiodarone. Drug interactions are a significant safety issue in the management of AF, including pharmacokinetic interactions in which plasma levels of the AAD are raised - increasing the risk of proarrhythmia - and concomitant use of drugs that prolong the QT interval. Notwithstanding these considerations, most patients with AF can be considered for rhythm control, provided there is adequate pre-treatment assessment and protocols for initiation, dosing and monitoring are followed with care.

Therapeutic hypothermia for out-of-hospital ventricular fibrillation survivors: a feasibility study comparing time to achieve target core temperature using conventional conductive cooling versus combined conductive plus pericranial convective cooling.

PubMed

Wass, C Thomas; White, Roger D; Schroeder, Darrell R; Mirzoyev, Sultan A; Warfield, Karen T

2013-04-01

Mild to moderate therapeutic hypothermia (TH) has been shown to improve survival and neurologic outcome, as well as to reduce healthcare costs in patients resuscitated from out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation. Accordingly, the American Heart Association has categorized this as a Class IB intervention. The therapeutic window for initiating TH is narrow, and thus, achieving target temperature expeditiously is of paramount importance to improve postresuscitative neurologic outcome. The present investigation is a feasibility study designed to assess the practicality and efficacy of including pericranial cooling in our postresuscitative TH protocol. Specifically, we compared time required to achieve target temperature (33°C) using our present standard of TH care (ie, conductive body cooling, conventional TH group) versus combined conductive body cooling plus convective (forced-air) head and neck cooling (combined TH group). Adult patients who experienced OHCA were included in the study provided TH could be initiated within 4 hours of resuscitation from ventricular fibrillation. Patients enrolled in both groups were cooled using the servo-controlled Arctic Sun conductive cooling system (Medivance, Inc, Louisville, CO). However, patients enrolled in the combined TH group also received forced-air pericranial cooling with an ambient temperature of approximately 13°C. In all cases, the target core (bladder) temperature was 33°C. The primary endpoint (ie, time required to achieve a core temperature of 33°C) was analyzed as a continuous variable and compared between groups using the rank sum test, whereas categorical variables were compared between groups using the chi-square test. Cardiac intensive care unit at a major tertiary care teaching center in Rochester, MN. Adult patients who experienced OHCA were included in the study. Patients enrolled in both groups were cooled using the servo-controlled Arctic Sun conductive cooling system

Stellar fibril magnetic systems. I - Reduced energy state

NASA Technical Reports Server (NTRS)

Parker, E. N.

1984-01-01

The remarkable fibril structure of the magnetic fields at the surface of the sun (with fibrils compressed to 1,000-2,000 gauss) lies outside existing statistical theories of magnetohydrodynamic turbulence. The total energy of the fibril field is enhanced by a factor of more than 100 above the energy for the mean field in a continuum state. The magnetic energy density within a fibril is of the order of 100 times the local kinetic energy density, so that no simple application of equipartition principles is possible. It is pointed out that the total energy of the atmosphere (thermal + gravitational + magnetic) is reduced by the fibril state of the field by avoiding the magnetic inhibition of the convective overturning, suggesting that the formation of the observed intense fibril state may be in response to the associated energy reduction. Calculation of the minimum total energy of a polytropic atmosphere permeated by magnetic fibrils yields theoretical fibril fields of the order of 1-5 kilogauss when characteristics appropriate to the solar convective zone are introduced, in rough agreement with the actual fields of 1-2 kilogauss. The polytrope model, although crude, establishes that a large reduction in total energy is made possible by the fibril state.

Rotor mapping and ablation to treat atrial fibrillation

PubMed Central

Zaman, Junaid A.B.; Peters, Nicholas S.; Narayan, Sanjiv M.

2015-01-01

Purpose of review Rotors have long been postulated to drive atrial fibrillation, but evidence has been limited to animal models. This changed recently with the demonstration using focal impulse and rotor modulation (FIRM) mapping that rotors act as human atrial fibrillation sources. This mechanistic approach to diagnosing the causes of atrial fibrillation in individual patients has been supported by substantially improved outcomes from FIRM-guided ablation, resulting in increased attention to rotors as therapeutic targets. Recent findings In this review, we outline the pathophysiology of rotors in animal and in-silico studies of fibrillation, and how this motivated FIRM mapping in humans. We highlight the characteristics of rotors in human atrial fibrillation, now validated by several techniques, with discussion on similar and discrepant findings between techniques. The interventional approaches to eliminate atrial fibrillation rotors are explained and the ablation results in latest studies using FIRM are discussed. Summary We propose that mapping localized sources for human atrial fibrillation, specifically rotors, is moving the field towards a unifying hypothesis that explains several otherwise contradictory observations in atrial fibrillation management. We conclude by suggesting areas of potential research that may reveal more about these critical sites and how these may lead to better and novel treatments for atrial fibrillation. PMID:25389649

Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

NASA Astrophysics Data System (ADS)

Nuryani, Nuryani; Satrio Nugroho, Anto

2017-11-01

Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

Natural history of idiopathic diabetes insipidus.

PubMed

Richards, Gail E; Thomsett, Michael J; Boston, Bruce A; DiMeglio, Linda A; Shulman, Dorothy I; Draznin, Martin

2011-10-01

To determine what percentage of diabetes insipidus (DI) in childhood is idiopathic and to assess the natural history of idiopathic DI. We conducted a retrospective chart review of 105 patients with DI who were born or had DI diagnosed between 1980-1989 at 3 medical centers. A second cohort of 30 patients from 6 medical centers in whom idiopathic DI was diagnosed after 1990 was evaluated retrospectively for subsequent etiologic diagnoses and additional hypothalamic/pituitary deficiencies and prospectively for quality of life. In the first cohort, 11% of patients had idiopathic DI. In the second cohort, additional hypothalamic/pituitary hormone deficiencies developed in 33%, and 37% received an etiologic diagnosis for DI. Health-related quality of life for all the patients with idiopathic DI was comparable with the healthy reference population. Only a small percentage of patients with DI will remain idiopathic after first examination. Other hormone deficiencies will develop later in one-third of those patients, and slightly more than one-third of those patients will have an etiology for the DI diagnosed. Long-term surveillance is important because tumors have been diagnosed as long as 21 years after the onset of DI. Quality of life for these patients is as good as the reference population. Copyright © 2011 Mosby, Inc. All rights reserved.

New-onset atrial fibrillation: an update.

PubMed

Omae, Takeshi; Inada, Eiichi

2018-06-01

New-onset atrial fibrillation (NOAF) is the most common perioperative complication of heart surgery, typically occurring in the perioperative period. NOAF commonly occurs in patients who are elderly, or have left atrial enlargement, or left ventricular hypertrophy. Various factors have been identified as being involved in the development of NOAF, and numerous approaches have been proposed for its prevention and treatment. Risk factors include diabetes, obesity, and metabolic syndrome. For prevention of NOAF, β-blockers and amiodarone are particularly effective and are recommended by guidelines. NOAF can be treated by rhythm/rate control, and antithrombotic therapy. Treatment is required in patients with decreased cardiac function, a heart rate exceeding 130 beats/min, or persistent NOAF lasting for ≥ 48 h. It is anticipated that anticoagulant therapies, as well as hemodynamic management, will also play a major role in the management of NOAF. When using warfarin as an anticoagulant, its dose should be adjusted based on PT-INR. PT-INR should be controlled between 2.0 and 3.0 in patients aged < 70 years and between 1.6 and 2.6 in those aged ≥ 70 years. Rate control combined with antithrombotic therapies for NOAF is expected to contribute to further advances in treatment and improvement of survival.

Vitamin D deficiency in chronic idiopathic urticaria.

PubMed

Movahedi, Masoud; Tavakol, Marzieh; Hirbod-Mobarakeh, Armin; Gharagozlou, Mohammad; Aghamohammadi, Asghar; Tavakol, Zahra; Momenzadeh, Kaveh; Nabavi, Mohammad; Dabbaghzade, Abbas; Mosallanejad, Asieh; Rezaei, Nima

2015-04-01

Chronic urticaria is the most common skin diseases, characterized by chronic cutaneous lesions which severely debilitates patients in several aspects of their everyday life. Vitamin D is known to exert several actions in the immune system and to influence function and differentiation of mast cells, central role players in the pathogenesis of chronic idiopathic urticaria. This study was performed to evaluate the relationship between vitamin D levels and susceptibility to chronic idiopathic urticaria. One hundred and fourteen patients with chronic idiopathic urticaria were recruited in this study along with one hundred and eighty seven sex-matched and age-matched healthy volunteers as the control group. For each patient, urticaria activity score was calculated and autologous serum skin test was done. Vitamin D metabolic statue was measured in serum as 25 hydroxyvitamin D using enzyme immunoassay method. Patients with chronic idiopathic urticaria significantly showed lower levels of vitamin D. Vitamin D deficiency was significantly associated with increased susceptibility to chronic idiopathic urticaria. There was a significant positive correlation between vitamin D levels and urticaria activity score. This study showed that patients with chronic idiopathic urticaria had reduced levels of vitamin D, while vitamin D deficiency could increase susceptibility to chronic idiopathic urticaria.

Flecainide-metoprolol combination reduces atrial fibrillation clinical recurrences and improves tolerability at 1-year follow-up in persistent symptomatic atrial fibrillation.

PubMed

Capucci, Alessandro; Piangerelli, Luca; Ricciotti, Jenny; Gabrielli, Domenico; Guerra, Federico

2016-11-01

Atrial fibrillation (AF) affects ∼2% of the total population. In order to prevent AF recurrences, many anti-arrhythmic drugs are currently available, but most of them are burdened by serious side effects and suboptimal efficacy. The aim of the present study was to test efficacy and safety of a combination of flecainide and metoprolol in preventing AF clinical recurrences. This study is a monocentric, prospective, randomized, open-blinded trial on 173 patients with a recent episode of paroxysmal or persistent AF. Patients were randomized into group A (flecainide + metoprolol; n = 80), group B (flecainide only; n = 72), or group C (metoprolol only; n = 21). Main exclusion criteria were recent acute coronary syndrome, heart failure New York Heart Association class III-IV, left ventricular ejection fraction <0.40, atrioventricular conduction disorders, and severe bradycardia. Primary endpoint was symptomatic recurrence over 1-year follow-up. Secondary endpoint was quality of life (QoL) over 1-year follow-up, as assessed by the SF-36 and Atrial Fibrillation Severity Scale questionnaires. Combination therapy with flecainide and metoprolol significantly reduced recurrences at 1-year follow-up when compared with flecainide alone in the whole population (66.7 vs. 46.8%; P < 0.001) and in patients with persistent AF (71.1 vs. 43.6%; P = 0.025) while adding beta-blocker therapy to paroxysmal AF showed no benefit over IC anti-arrhythmic drug-only. Patients randomized to combination therapy experienced a significant improvement of QoL when compared with those assigned to a flecainide-only regimen irrespective of AF type. Flecainide-metoprolol combination therapy improves effectiveness of rhythm control in persistent symptomatic AF and increases tolerability, with a concomitant reduction of side effects and a better compliance. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Asymptomatic Ventricular Pre-excitation: Between Sudden Cardiac Death and Catheter Ablation.

PubMed

Brugada, Josep; Keegan, Roberto

2018-03-01

Debate about the best clinical approach to the management of asymptomatic patients with ventricular pre-excitation and advice on whether or not to invasively stratify and ablate is on-going. Weak evidence about the real risk of sudden cardiac death and the potential benefit of catheter ablation has probably prevented the clarification of action in this not infrequent and sometimes conflicting clinical situation. After analysing all available data, real evidence-based medicine could be the alternative strategy for managing this group of patients. According to recent surveys, most electrophysiologists invasively stratify. Based on all accepted risk factors - younger age, male, associated structural heart disease, posteroseptal localisation, ability of the accessory pathway to conduct anterogradely at short intervals of ≤250 milliseconds and inducibility of sustained atrioventricular re-entrant tachycardia and/or atrial fibrillation - a shared decisionmaking process on catheter ablation is proposed.

Thyrotoxic atrial fibrillation.

PubMed

Parmar, Malvinder S

2005-01-04

Atrial fibrillation is the most common cardiac complication of hyperthyroidism and occurs in 15% of patients with hyperthyroidism. It is associated with a higher risk of thromboembolism that often involves the central nervous system. Oral anticoagulation is important in the majority of these patients to prevent thromboembolic complications. These patients require adjustment in the dose of various rate-controlling agents because of increased clearance associated with hyperthyroidism and a decrease in warfarin dosage because of increased clearance of vitamin K-dependent clotting factors. The management of thyrotoxic atrial fibrillation is summarized in this clinical review.

Arrhythmogenic Right Ventricular Cardiomyopathy in an Endurance Athlete Presenting with Ventricular Tachycardia and Normal Right Ventricular Function.

PubMed

Hedley, Jeffrey S; Al Mheid, Ibhar; Alikhani, Zoubin; Pernetz, Maria A; Kim, Jonathan H

2017-08-01

Arrhythmogenic right ventricular cardiomyopathy, a genetically inherited disease that results in fibrofatty replacement of normal cardiac myocytes, has been associated with sudden cardiac death in athletes. Long-term participation in endurance exercise hastens the development of both the arrhythmic and structural arrhythmogenic right ventricular cardiomyopathy phenotypes. We describe the unusual case of a 34-year-old, symptomatic, female endurance athlete who had arrhythmogenic right ventricular cardiomyopathy in the presence of a structurally normal right ventricle. Clinicians should be aware of this infrequent presentation when evaluating athletic patients who have ventricular arrhythmias and normal findings on cardiac imaging studies.

Regional TNFα mapping in the brain reveals the striatum as a neuroinflammatory target after ventricular fibrillation cardiac arrest in rats☆

PubMed Central

Janata, Andreas; Magnet, Ingrid A.M.; Uray, Thomas; Stezoski, Jason P.; Janesko-Feldman, Keri; Tisherman, Samuel A.; Kochanek, Patrick M.; Drabek, Tomas

2014-01-01

Cardiac arrest (CA) triggers neuroinflammation that could play a role in a delayed neuronal death. In our previously established rat model of ventricular fibrillation (VF) CA characterized by extensive neuronal death, we tested the hypothesis that individual brain regions have specific neuroinflammatory responses, as reflected by regional brain tissue levels of tumor necrosis factor (TNF)α and other cytokines. In a prospective study, rats were randomized to 6 min (CA6), 8 min (CA8) or 10 min (CA10) of VF CA, or sham group. Cortex, striatum, hippocampus and cerebellum were evaluated for TNFα and interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12 and interferon gamma at 3 h, 6 h or 14 d after CA by ELISA and Luminex. Immunohistochemistry was used to determine the cell source of TNFα. CA resulted in a selective TNFα response with significant regional and temporal differences. At 3 h after CA, TNFα-levels increased in all regions depending on the duration of the insult. The most pronounced increase was observed in striatum that showed 20-fold increase in CA10 vs. sham, and 3-fold increase vs. CA6 or CA8 group, respectively (p < 0.01). TNFα levels in striatum decreased between 3 h and 6 h, but increased in other regions between 3 h and 14 d. TNFα levels remained twofold higher in CA6 vs. shams across brain regions at 14 d (p < 0.01). In contrast to pronounced TNFα response, other cytokines showed only a minimal increase in CA6 and CA8 groups vs. sham in all brain regions with the exception that IL-1β increased twofold in cerebellum and striatum (p < 0.01). TNFα colocalized with neurons. In conclusion, CA produced a duration-dependent acute TNFα response, with dramatic increase in the striatum where TNFα colocalized with neurons. Increased TNFα levels persist for at least two weeks. This TNFα surge contrasts the lack of an acute increase in other cytokines in brain after CA. Given that striatum is a selectively vulnerable brain region, our data

Difference in the Clinical Characteristics of Ventricular Fibrillation Occurrence in the Early Phase of an Acute Myocardial Infarction Between Patients With and Without J Waves.

PubMed

Naruse, Yoshihisa; Nogami, Akihiko; Harimura, Yoshie; Ishibashi, Mayu; Noguchi, Yuichi; Sekiguchi, Yukio; Sato, Akira; Aonuma, Kazutaka

2015-08-01

We recently showed that the presence of J waves increases the risk of ventricular fibrillation (VF) occurrence in the early phase of an acute myocardial infarction (AMI). This study aimed to evaluate the clinical characteristics of VF occurrences in the early phase of an AMI between patients with and without J waves. This retrospective, observational study included 281 consecutive patients with an AMI (69 ± 12 years; 207 men) in whom 12-lead ECGs before AMI onset could be evaluated. The patients were classified based on a VF occurrence <48 hours after AMI onset and the presence of J waves. J waves were electrocardiographically defined as an elevation of the terminal portion of the QRS complex of >0.1 mV from baseline in at least 2 contiguous inferior or lateral leads. VF occurred in 24 patients, and J waves were present in 37. VF occurrence was more prevalent in the patients with than without J waves (27% vs. 6%; P < 0.001). Among the 244 patients without J waves, peak creatine kinase level (P < 0.01), number of diseased coronary arteries (P < 0.01), and male sex (P < 0.05) were higher in the patients with than without VF occurrence. However, among the 37 patients with J waves, there was no significant difference in these variables. There was no association between the location of J waves and the infarct area. In patients with AMI, those with J waves were more likely to develop VF and less likely to have high-risk clinical characteristics than those without J waves. © 2015 Wiley Periodicals, Inc.

Efficacy of amiodarone and lidocaine for preventing ventricular fibrillation after aortic cross-clamp release in open heart surgery: a meta-analysis of randomized controlled trials.

PubMed

Zheng, Yong; Gu, Qiang; Chen, Hong-Wu; Peng, Huai-Ming; Jia, Dong-Yu; Zhou, Yu; Xiang, Mei-Xiang

The relative preventative efficacy of amiodarone and lidocaine for ventricular fibrillation (VF) after release of an aortic cross-clamp (ACC) during open heart surgery has not been determined. This meta-analysis was designed to systematically evaluate the influence of amiodarone, lidocaine, or placebo on the incidence of VF after ACC. Prospective randomized controlled trials (RCTs) that compared the VF-preventative effects of amiodarone with lidocaine, or amiodarone or lidocaine with placebo were included. PubMed, EMBASE, and the Cochrane Library were searched for relevant RCTs. Fixed or randomized effect models were applied according to the heterogeneity of the data from the selected studies. We included eight RCTs in the analysis. Pooled results suggested that the preventative effects of amiodarone and lidocaine were comparable (relative risk (RR)=1.12, 95% confidence interval (CI): 0.70 to 1.80, P=0.63), but both were superior to the placebo (amiodarone, RR=0.71, 95% CI: 0.51 to 1.00, P=0.05; lidocaine, RR=0.63, 95% CI: 0.46 to 0.88, P=0.006). The percentage of patients requiring electric defibrillation counter shocks (DCSs) did not differ significantly among patients administered amiodarone (RR=0.21, 95% CI: 0.04 to 1.19, P=0.08), lidocaine (RR=2.44, 95% CI: 0.13 to 44.02, P=0.55), or the placebo (RR=0.56, 95% CI: 0.25 to 1.25, P=0.16). Amiodarone and lidocaine are comparably effective in preventing VF after ACC, but the percentage of patients who subsequently require DCSs does not differ among those administered amiodarone, lidocaine, or placebo.

Relation between adolescent idiopathic scoliosis and morphologic somatotypes.

PubMed

LeBlanc, R; Labelle, H; Rivard, C H; Poitras, B

1997-11-01

A prospective and controlled comparative study. To verify the difference in morphologic appearance between a group of adolescents with progressive adolescent idiopathic scoliosis and a control group of normal adolescents. In a previous retrospective study, the possibility of a relation between progressive adolescent idiopathic scoliosis and specific morphotypes was demonstrated. Fifty-two adolescent girls with progressive adolescent idiopathic scoliosis were compared with an age-matched control group of 62 unaffected girls using a classification technique based on morphologic somatotypes. Morphotypes were evaluated with standardized pre-established criteria based on Sheldon's technique. Patients with progressive adolescent idiopathic scoliosis showed significantly less mesomorphism (mean value of 0.88 +/- 0.51) than control girls (mean value of 1.72 +/- 0.52). Adolescent girls with progressive adolescent idiopathic scoliosis have a morphologic somatotype that is different from the normal adolescent population. Subjects with progressive adolescent idiopathic scoliosis are significantly less mesomorphic than control girls. This observation may be of value as a predictive factor for early identification of subjects with adolescent idiopathic scoliosis at greater risk of progression.

Synaptic Plasticity in Cardiac Innervation and Its Potential Role in Atrial Fibrillation

PubMed Central

Ashton, Jesse L.; Burton, Rebecca A. B.; Bub, Gil; Smaill, Bruce H.; Montgomery, Johanna M.

2018-01-01

Synaptic plasticity is defined as the ability of synapses to change their strength of transmission. Plasticity of synaptic connections in the brain is a major focus of neuroscience research, as it is the primary mechanism underpinning learning and memory. Beyond the brain however, plasticity in peripheral neurons is less well understood, particularly in the neurons innervating the heart. The atria receive rich innervation from the autonomic branch of the peripheral nervous system. Sympathetic neurons are clustered in stellate and cervical ganglia alongside the spinal cord and extend fibers to the heart directly innervating the myocardium. These neurons are major drivers of hyperactive sympathetic activity observed in heart disease, ventricular arrhythmias, and sudden cardiac death. Both pre- and postsynaptic changes have been observed to occur at synapses formed by sympathetic ganglion neurons, suggesting that plasticity at sympathetic neuro-cardiac synapses is a major contributor to arrhythmias. Less is known about the plasticity in parasympathetic neurons located in clusters on the heart surface. These neuronal clusters, termed ganglionated plexi, or “little brains,” can independently modulate neural control of the heart and stimulation that enhances their excitability can induce arrhythmia such as atrial fibrillation. The ability of these neurons to alter parasympathetic activity suggests that plasticity may indeed occur at the synapses formed on and by ganglionated plexi neurons. Such changes may not only fine-tune autonomic innervation of the heart, but could also be a source of maladaptive plasticity during atrial fibrillation. PMID:29615932

Perspective: Update on Idiopathic Intracranial Hypertension

PubMed Central

Bruce, Beau B.; Biousse, Valérie; Newman, Nancy J.

2011-01-01

Purpose Provide an update on various features of idiopathic intracranial hypertension. Design Perspective. Methods Selected articles on the epidemiology, clinical and imaging features, natural history, pathophysiology, and treatment of idiopathic intracranial hypertension were reviewed and interpreted in the context of the authors’ clinical and research experience. Results Idiopathic intracranial hypertension is primarily a disease of obese women of childbearing age, but it can affect patients of any weight, sex, and age. Although a relatively rare disorder, idiopathic intracranial hypertension’s associated costs in the U.S. entail hundreds of millions of dollars. Even following treatment, headaches are frequently persistent and may require the continued involvement of a neurologist. Quality of life reductions and depression are common among idiopathic intracranial hypertension patients. However, visual dysfunction, especially visual field abnormalities, represents the major morbidity of this disorder, and serial automated perimetry remains the primary mode of patient monitoring. Patients who are men, black, very obese, or anemic are at higher risk of visual loss. Vitamin A metabolism, adipose tissue as an actively secreting endocrine tissue, and cerebral venous abnormalities are areas of active study regarding idiopathic intracranial hypertension’s pathophysiology. Treatment studies show that lumbar puncture is a valuable treatment (in addition to its crucial diagnostic role) and that weight management is critical. However, open questions remain regarding the efficacy of acetazolamide, CSF diversion procedures, and cerebral venous stenting. Conclusions Many questions remain unanswered about idiopathic intracranial hypertension. Ongoing studies, especially an ongoing NIH-funded clinical trial of acetazolamide, should provide more insight into this important, yet poorly understood syndrome of isolated intracranial hypertension. PMID:21696699

RR-Interval variance of electrocardiogram for atrial fibrillation detection

NASA Astrophysics Data System (ADS)

Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

2016-11-01

Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

Spectral analysis-based risk score enables early prediction of mortality and cerebral performance in patients undergoing therapeutic hypothermia for ventricular fibrillation and comatose status

PubMed Central

Filgueiras-Rama, David; Calvo, Conrado J.; Salvador-Montañés, Óscar; Cádenas, Rosalía; Ruiz-Cantador, Jose; Armada, Eduardo; Rey, Juan Ramón; Merino, J.L.; Peinado, Rafael; Pérez-Castellano, Nicasio; Pérez-Villacastín, Julián; Quintanilla, Jorge G.; Jiménez, Santiago; Castells, Francisco; Chorro, Francisco J.; López-Sendón, J.L.; Berenfeld, Omer; Jalife, José; López de Sá, Esteban; Millet, José

2017-01-01

Background Early prognosis in comatose survivors after cardiac arrest due to ventricular fibrillation (VF) is unreliable, especially in patients undergoing mild hypothermia. We aimed at developing a reliable risk-score to enable early prediction of cerebral performance and survival. Methods Sixty-one out of 239 consecutive patients undergoing mild hypothermia after cardiac arrest, with eventual return of spontaneous circulation (ROSC), and comatose status on admission fulfilled the inclusion criteria. Background clinical variables, VF time and frequency domain fundamental variables were considered. The primary and secondary outcomes were a favorable neurological performance (FNP) during hospitalization and survival to hospital discharge, respectively. The predictive model was developed in a retrospective cohort (n=32; September 2006–September 2011, 48.5 ± 10.5 months of follow-up) and further validated in a prospective cohort (n = 29; October 2011–July 2013, 5 ± 1.8 months of follow-up). Results FNP was present in 16 (50.0%) and 21 patients (72.4%) in the retrospective and prospective cohorts, respectively. Seventeen (53.1%) and 21 patients (72.4%), respectively, survived to hospital discharge. Both outcomes were significantly associated (p < 0.001). Retrospective multivariate analysis provided a prediction model (sensitivity= 0.94, specificity = 1) that included spectral dominant frequency, derived power density and peak ratios between high and low frequency bands, and the number of shocks delivered before ROSC. Validation on the prospective cohort showed sensitivity = 0.88 and specificity = 0.91. A model-derived risk-score properly predicted 93% of FNP. Testing the model on follow-up showed a c-statistic ≥ 0.89. Conclusions A spectral analysis-based model reliably correlates time-dependent VF spectral changes with acute cerebral injury in comatose survivors undergoing mild hypothermia after cardiac arrest. PMID:25828128

Left ventricular systolic dysfunction, heart failure, and the risk of stroke and systemic embolism in patients with atrial fibrillation: insights from the ARISTOTLE trial.

PubMed

McMurray, John J V; Ezekowitz, Justin A; Lewis, Basil S; Gersh, Bernard J; van Diepen, Sean; Amerena, John; Bartunek, Jozef; Commerford, Patrick; Oh, Byung-Hee; Harjola, Veli-Pekka; Al-Khatib, Sana M; Hanna, Michael; Alexander, John H; Lopes, Renato D; Wojdyla, Daniel M; Wallentin, Lars; Granger, Christopher B

2013-05-01

We examined the risk of stroke or systemic embolism (SSE) conferred by heart failure (HF) and left ventricular systolic dysfunction (LVSD) in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation Trial (ARISTOTLE), as well as the effect of apixaban versus warfarin. The risk of a number of outcomes, including the composite of SSE or death (to take account of competing risks) and composite of SSE, major bleeding, or death (net clinical benefit) were calculated in 3 patient groups: (1) no HF/no LVSD (n=8728), (2) HF/no LVSD (n=3207), and (3) LVSD with/without symptomatic HF (n=2736). The rate of both outcomes was highest in patients with LVSD (SSE or death 8.06; SSE, major bleeding, or death 10.46 per 100 patient-years), intermediate for HF but preserved LV systolic function (5.32; 7.24), and lowest in patients without HF or LVSD (1.54; 5.27); each comparison P<0.0001. Each outcome was less frequent in patients treated with apixaban: in all ARISTOTLE patients, the apixaban/warfarin hazard ratio for SSE or death was 0.89 (95% confidence interval, 0.81-0.98; P=0.02); for SSE, major bleed, or death it was 0.85 (0.78-0.92; P<0.001). There was no heterogeneity of treatment effect across the 3 groups. Patients with LVSD (with/without HF) had a higher risk of SSE or death (but similar rate of SSE) compared with patients with HF but preserved LV systolic function; both had a greater risk than patients without either HF or LVSD. Apixaban reduced the risk of both outcomes more than warfarin in all 3 patient groups. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00412984.

Differential responses of rabbit ventricular and atrial transient outward current (Ito) to the Ito modulator NS5806.

PubMed

Cheng, Hongwei; Cannell, Mark B; Hancox, Jules C

2017-03-01

Transient outward potassium current (I to ) in the heart underlies phase 1 repolarization of cardiac action potentials and thereby affects excitation-contraction coupling. Small molecule activators of I to may therefore offer novel treatments for cardiac dysfunction, including heart failure and atrial fibrillation. NS5806 has been identified as a prototypic activator of canine I to This study investigated, for the first time, actions of NS5806 on rabbit atrial and ventricular I to Whole cell patch-clamp recordings of I to and action potentials were made at physiological temperature from rabbit ventricular and atrial myocytes. 10  μ mol/L NS5806 increased ventricular I to with a leftward shift in I to activation and accelerated restitution. At higher concentrations, stimulation of I to was followed by inhibition. The EC 50 for stimulation was 1.6  μ mol/L and inhibition had an IC 50 of 40.7  μ mol/L. NS5806 only inhibited atrial I to (IC 50 of 18  μ mol/L) and produced a modest leftward shifts in I to activation and inactivation, without an effect on restitution. 10  μ mol/L NS5806 shortened ventricular action potential duration (APD) at APD 20 -APD 90 but prolonged atrial APD NS5806 also reduced atrial AP upstroke and amplitude, consistent with an additional atrio-selective effect on Na + channels. In contrast to NS5806, flecainide, which discriminates between Kv1.4 and 4.x channels, produced similar levels of inhibition of ventricular and atrial I to NS5806 discriminates between rabbit ventricular and atrial I to, with mixed activator and inhibitor actions on the former and inhibitor actions against the later. NS5806 may be of significant value for pharmacological interrogation of regional differences in native cardiac I to . © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Chirality and chiroptical properties of amyloid fibrils.

PubMed

Dzwolak, Wojciech

2014-09-01

Chirality of amyloid fibrils-linear beta-sheet-rich aggregates of misfolded protein chains-often manifests in morphological traits such as helical twist visible in atomic force microscopy and in chiroptical properties accessible to vibrational circular dichroism (VCD). According to recent studies the relationship between molecular chirality of polypeptide building blocks and superstructural chirality of amyloid fibrils may be more intricate and less deterministic than previously assumed. Several puzzling experimental findings have put into question earlier intuitive ideas on: 1) the bottom-up chirality transfer upon amyloidogenic self-assembly, and 2) the structural origins of chiroptical properties of protein aggregates. For example, removal of a single amino acid residue from an amyloidogenic all-L peptide was shown to reverse handedness of fibrils. On the other hand, certain types of amyloid aggregates revealed surprisingly strong VCD spectra with the sign and shape dependent on the conditions of fibrillation. Hence, microscopic and chiroptical studies have highlighted chirality as one more aspect of polymorphism of amyloid fibrils. This brief review is intended to outline the current state of research on amyloid-like fibrils from the perspective of their structural and superstructural chirality and chiroptical properties. © 2014 Wiley Periodicals, Inc.

Modeling generic aspects of ideal fibril formation

NASA Astrophysics Data System (ADS)

Michel, D.

2016-01-01

Many different proteins self-aggregate into insoluble fibrils growing apically by reversible addition of elementary building blocks. But beyond this common principle, the modalities of fibril formation are very disparate, with various intermediate forms which can be reshuffled by minor modifications of physico-chemical conditions or amino-acid sequences. To bypass this complexity, the multifaceted phenomenon of fibril formation is reduced here to its most elementary principles defined for a linear prototype of fibril. Selected generic features, including nucleation, elongation, and conformational recruitment, are modeled using minimalist hypotheses and tools, by separating equilibrium from kinetic aspects and in vitro from in vivo conditions. These reductionist approaches allow to bring out known and new rudiments, including the kinetic and equilibrium effects of nucleation, the dual influence of elongation on nucleation, the kinetic limitations on nucleation and fibril numbers, and the accumulation of complexes in vivo by rescue from degradation. Overlooked aspects of these processes are also pointed: the exponential distribution of fibril lengths can be recovered using various models because it is attributable to randomness only. It is also suggested that the same term "critical concentration" is used for different things, involved in either nucleation or elongation.

The Natural History of Idiopathic Scoliosis During Growth: A Meta-Analysis.

PubMed

Di Felice, Francesca; Zaina, Fabio; Donzelli, Sabrina; Negrini, Stefano

2018-05-01

The aim of the study was to provide a meta-analysis of current literature concerning the natural history of idiopathic scoliosis during growth. A comprehensive search of Medline, Embase, And Scopus databases was conducted up to November 2016. Eligible works were prospective or retrospective studies that enrolled patients with infantile idiopathic scoliosis, juvenile idiopathic scoliosis, or adolescent idiopathic scoliosis, followed up without any treatment from the time of detection. A meta-analysis for proportion was performed. The following studies were grouped per diagnosis: infantile idiopathic scoliosis, juvenile idiopathic scoliosis, and adolescent idiopathic scoliosis. Of the 1797 citations screened, we assessed 61 full-text articles and included 13 of these (2301 participants). Three studies included infantile idiopathic scoliosis patients (347 participants), five studies included a mixed population of juvenile idiopathic scoliosis and adolescent idiopathic scoliosis (1330 participants), and five studies included adolescent idiopathic scoliosis patients only (624 participants). The random pooled estimated progression rate was 49% (95% confidence interval = 1%-97%) for infantile idiopathic scoliosis, 49% in a mixed group of patients affected by juvenile idiopathic scoliosis or adolescent idiopathic scoliosis (95% confidence interval = 19%-79%), and 42% in adolescent idiopathic scoliosis (95% confidence interval = 11%-73%). During growth, idiopathic scoliosis tends to progress in a high percentage of cases. The progression rate varies according to the age at diagnosis, with infantile scoliosis being the most unpredictable. There are many confounders, such as age, Risser sign and baseline Cobb angles that were not consistent among studies, making the data very heterogeneous.

Sulfates Dramatically Stabilize a Salt-Dependent Type of Glucagon Fibrils

PubMed Central

Pedersen, Jesper Søndergaard; Flink, James M.; Dikov, Dantcho; Otzen, Daniel Erik

2006-01-01

Recent work suggests that protein fibrillation mechanisms and the structure of the resulting protein fibrils are very sensitive to environmental conditions such as temperature and ionic strength. Here we report the effect of several inorganic salts on the fibrillation of glucagon. At acidic pH, fibrillation is much less influenced by cations than anions, for which the effects follow the electroselectivity series; e.g., the effect of sulfate is ∼65-fold higher than that of chloride per mole. Increased salt concentrations generally accelerate fibrillation, but result in formation of an alternate type of fibrils. Stability of these fibrils is highly affected by changes in anion concentration; the apparent melting temperature is increased by ∼22°C for any 10-fold concentration increase, indicating that the fibrils cannot exist without anions. In contrast, fibrillation under alkaline conditions is more affected by cations than anions. We conclude that ions interact directly as structural ligands with glucagon fibrils where they coordinate charges and assist in formation of new fibrils. As ex vivo amyloid plaques often contain large amounts of highly sulfated organic molecules, the specific effects of sulfate ions on glucagon may have general relevance in the study of amyloidosis and other protein deposition diseases. PMID:16533857

Protein Polymerization into Fibrils from the Viewpoint of Nucleation Theory.

PubMed

Kashchiev, Dimo

2015-11-17

The assembly of various proteins into fibrillar aggregates is an important phenomenon with wide implications ranging from human disease to nanoscience. Using general kinetic results of nucleation theory, we analyze the polymerization of protein into linear or helical fibrils in the framework of the Oosawa-Kasai (OK) model. We show that while within the original OK model of linear polymerization the process does not involve nucleation, within a modified OK model it is nucleation-mediated. Expressions are derived for the size of the fibril nucleus, the work for fibril formation, the nucleation barrier, the equilibrium and stationary fibril size distributions, and the stationary fibril nucleation rate. Under otherwise equal conditions, this rate decreases considerably when the short (subnucleus) fibrils lose monomers much more frequently than the long (supernucleus) fibrils, a feature that should be born in mind when designing a strategy for stymying or stimulating fibril nucleation. The obtained dependence of the nucleation rate on the concentration of monomeric protein is convenient for experimental verification and for use in rate equations accounting for nucleation-mediated fibril formation. The analysis and the results obtained for linear fibrils are fully applicable to helical fibrils whose formation is describable by a simplified OK model. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Nonlinear Dynamical Analysis of Fibrillation

NASA Astrophysics Data System (ADS)

Kerin, John A.; Sporrer, Justin M.; Egolf, David A.

2013-03-01

The development of spatiotemporal chaotic behavior in heart tissue, termed fibrillation, is a devastating, life-threatening condition. The chaotic behavior of electrochemical signals, in the form of spiral waves, causes the muscles of the heart to contract in an incoherent manner, hindering the heart's ability to pump blood. We have applied the mathematical tools of nonlinear dynamics to large-scale simulations of a model of fibrillating heart tissue to uncover the dynamical modes driving this chaos. By studying the evolution of Lyapunov vectors and exponents over short times, we have found that the fibrillating tissue is sensitive to electrical perturbations only in narrow regions immediately in front of the leading edges of spiral waves, especially when these waves collide, break apart, or hit the edges of the tissue sample. Using this knowledge, we have applied small stimuli to areas of varying sensitivity. By studying the evolution of the effects of these perturbations, we have made progress toward controlling the electrochemical patterns associated with heart fibrillation. This work was supported by the U.S. National Science Foundation (DMR-0094178) and Research Corporation.

Mechanical properties of a collagen fibril under simulated degradation.

PubMed

Malaspina, David C; Szleifer, Igal; Dhaher, Yasin

2017-11-01

Collagen fibrils are a very important component in most of the connective tissue in humans. An important process associated with several physiological and pathological states is the degradation of collagen. Collagen degradation is usually mediated by enzymatic and non-enzymatic processes. In this work we use molecular dynamics simulations to study the influence of simulated degradation on the mechanical properties of the collagen fibril. We applied tensile stress to the collagen fiber at different stages of degradation. We compared the difference in the fibril mechanical priorities due the removal of enzymatic crosslink, surface degradation and volumetric degradation. As anticipated, our results indicated that, regardless of the degradation scenario, fibril mechanical properties is reduced. The type of degradation mechanism (crosslink, surface or volumetric) expressed differential effect on the change in the fibril stiffness. Our simulation results showed dramatic change in the fibril stiffness with a small amount of degradation. This suggests that the hierarchical structure of the fibril is a key component for the toughness and is very sensitive to changes in the organization of the fibril. The overall results are intended to provide a theoretical framework for the understanding the mechanical behavior of collagen fibrils under degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of self-gated radial cardiovascular magnetic resonance to detect and classify arrhythmias (atrial fibrillation and premature ventricular contraction).

PubMed

Piekarski, Eve; Chitiboi, Teodora; Ramb, Rebecca; Feng, Li; Axel, Leon

2016-11-25

Arrhythmia can significantly alter the image quality of cardiovascular magnetic resonance (CMR); automatic detection and sorting of the most frequent types of arrhythmias during the CMR acquisition could potentially improve image quality. New CMR techniques, such as non-Cartesian CMR, can allow self-gating: from cardiac motion-related signal changes, we can detect cardiac cycles without an electrocardiogram. We can further use this data to obtain a surrogate for RR intervals (valley intervals: VV). Our purpose was to evaluate the feasibility of an automated method for classification of non-arrhythmic (NA) (regular cycles) and arrhythmic patients (A) (irregular cycles), and for sorting of common arrhythmia patterns between atrial fibrillation (AF) and premature ventricular contraction (PVC), using the cardiac motion-related signal obtained during self-gated free-breathing radial cardiac cine CMR with compressed sensing reconstruction (XD-GRASP). One hundred eleven patients underwent cardiac XD-GRASP CMR between October 2015 and February 2016; 33 were included for retrospective analysis with the proposed method (6 AF, 8 PVC, 19 NA; by recent ECG). We analyzed the VV, using pooled statistics (histograms) and sequential analysis (Poincaré plots), including the median (medVV), the weighted mean (meanVV), the total number of VV values (VVval), and the total range (VVTR) and half range (VVHR) of the cumulative frequency distribution of VV, including the median to half range (medVV/VVHR) and the half range to total range (VVHR/VVTR) ratios. We designed a simple algorithm for using the VV results to differentiate A from NA, and AF from PVC. Between NA and A, meanVV, VVval, VVTR, VVHR, medVV/VVHR and VVHR/VVTR ratios were significantly different (p values = 0.00014, 0.0027, 0.000028, 5×10 -9 , 0.002, respectively). Between AF and PVC, meanVV, VVval and medVV/VVHR ratio were significantly different (p values = 0.018, 0.007, 0.044, respectively). Using our algorithm

Phenotyping Cardiac Arrest: Bench and Bedside Characterization of Brain and Heart Injury Based on Etiology.

PubMed

Uray, Thomas; Lamade, Andrew; Elmer, Jonathan; Drabek, Tomas; Stezoski, Jason P; Missé, Amalea; Janesko-Feldman, Keri; Garman, Robert H; Chen, Niel; Kochanek, Patrick M; Dezfulian, Cameron; Callaway, Clifton W; Doshi, Ankur A; Frisch, Adam; Guyette, Francis X; Reynolds, Josh C; Rittenberger, Jon C

2018-06-01

Cardiac arrest etiology may be an important source of between-patient heterogeneity, but the impact of etiology on organ injury is unknown. We tested the hypothesis that asphyxial cardiac arrest results in greater neurologic injury than cardiac etiology cardiac arrest (ventricular fibrillation cardiac arrest), whereas ventricular fibrillation cardiac arrest results in greater cardiovascular dysfunction after return of spontaneous circulation. Prospective observational human and randomized animal study. University laboratory and ICUs. Five-hundred forty-three cardiac arrest patients admitted to ICU. Seventy-five male Sprague-Dawley rats. We examined neurologic and cardiovascular injury in Isoflurane-anesthetized rat cardiac arrest models matched by ischemic time. Hemodynamic and neurologic outcomes were assessed after 5 minutes no flow asphyxial cardiac arrest or ventricular fibrillation cardiac arrest. Comparison was made to injury patterns observed after human asphyxial cardiac arrest or ventricular fibrillation cardiac arrest. In rats, cardiac output (20 ± 10 vs 45 ± 9 mL/min) and pH were lower and lactate higher (9.5 ± 1.0 vs 6.4 ± 1.3 mmol/L) after return of spontaneous circulation from ventricular fibrillation cardiac arrest versus asphyxial cardiac arrest (all p < 0.01). Asphyxial cardiac arrest resulted in greater early neurologic deficits, 7-day neuronal loss, and reduced freezing time (memory) after conditioned fear (all p < 0.05). Brain antioxidant reserves were more depleted following asphyxial cardiac arrest. In adjusted analyses, human ventricular fibrillation cardiac arrest was associated with greater cardiovascular injury based on peak troponin (7.8 ng/mL [0.8-57 ng/mL] vs 0.3 ng/mL [0.0-1.5 ng/mL]) and ejection fraction by echocardiography (20% vs 55%; all p < 0.0001), whereas asphyxial cardiac arrest was associated with worse early neurologic injury and poor functional outcome at hospital discharge (n = 46 [18%] vs 102 [44%]; p < 0.0001). Most

Metastable Amyloid Phases and their Conversion to Mature Fibrils

NASA Astrophysics Data System (ADS)

Muschol, Martin; Miti, Tatiana; Mulaj, Mentor; Schmit, Jeremy

Self-assembly of proteins into amyloid fibrils plays a key role in both functional biological responses and pathogenic disorders which include Alzheimer's disease and type II diabetes. Amyloid fibril assembly frequently generates compact oligomeric and curvilinear polymeric intermediates which are implicated to be toxic to cells. Yet, the relation between these early-stage oligomeric aggregates and late-stage rigid fibrils, which are the hallmark structure of amyloid plaques, has remained unclear. Our measurements indicate that lysozyme amyloid oligomers and their curvilinear fibrils only form after crossing a salt and protein concentration dependent threshold. These oligomeric aggregates are structurally distinct from rigid fibrils and are metastable against nucleation and growth of rigid fibrils. Our experimental transition boundaries match well with colloidal model predictions accounting for salt-modulated charge repulsion. We also report our preliminary findings on the mechanism by which these metastable oligomeric phases are converted into stable amyloid fibrils.

Atrial Fibrillation and Heart Failure - Cause or Effect?

PubMed

Prabhu, Sandeep; Voskoboinik, Aleksandr; Kaye, David M; Kistler, Peter M

2017-09-01

There are emerging epidemics of atrial fibrillation (AF) and heart failure in most developed countries, with a significant health burden. Due to many shared pathophysiological mechanisms, which facilitate the maintenance of each condition, AF and heart failure co-exist in up to 30% of patients. In the circumstance where known structural causes of heart failure (such as myocardial infarction) are absent, patients presenting with both conditions present a unique challenge, particularly as the temporal relationship of each condition can often remain elusive from the clinical history. The question of whether the AF is driving, or significantly contributing to the left ventricular (LV) dysfunction, rather than merely a consequence of heart failure, has become ever more pertinent, especially as catheter ablation now offers a significant advancement over existing rhythm control strategies. This paper will review the inter-related physiological drivers of AF and heart failure before considering the implications from the outcomes of recent clinical trials in patients with AF and heart failure. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

[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.

Core sequence of PAPf39 amyloid fibrils and mechanism of pH-dependent fibril formation: the role of monomer conformation.

PubMed

French, Kinsley C; Makhatadze, George I

2012-12-21

PAPf39, a 39-residue peptide fragment from human prostatic acidic phosphatase, has been shown to form amyloid fibrils in semen (SEVI), which increase HIV infectivity by up to 5 orders of magnitude. The sequence of the PAPf39 fibrillar core was identified using hydrogen-deuterium exchange (HDX) mass spectrometry and protease protection assays. The central and C-terminal regions are highly protected from HDX and proteolytic cleavage and, thus, are part of the fibrillar core. Conversely, the N-terminal region is unprotected from HDX and proteolytic cleavage, suggesting that it is exposed and not part of the fibrillar core. This finding was tested using two N-terminal truncated variants, PAPf39Δ1-8 and PAPf39Δ1-13. Both variants formed amyloid fibrils at neutral pH. However, these variants showed a markedly different pH dependence of fibril formation versus that of PAPf39. PAPf39 fibrils can form at pH 7.7, but not at pH 5.5 or 2.5, while both N-terminally truncated variants can form fibrils at these pH values. Thus, the N-terminal region is not necessary for fibril formation but modulates the pH dependence of PAPf39 fibril formation. PAPf39Δ1-8 and PAPf39Δ1-13 are capable of seeding PAPf39 fibril formation at neutral pH, suggesting that these variants are structurally compatible with PAPf39, yet no mixed fibril formation occurs between the truncated variants and PAPf39 at low pH. This suggests that pH affects the PAPf39 monomer conformational ensemble, which is supported by far-UV circular dichroism spectroscopy. A conceptual model describing the pH dependence of PAPf39 aggregation is proposed and provides potential biological implications.

Implantation of the Medtronic Harmony Transcatheter Pulmonary Valve Improves Right Ventricular Size and Function in an Ovine Model of Postoperative Chronic Pulmonary Insufficiency.

PubMed

Schoonbeek, Rosanne C; Takebayashi, Satoshi; Aoki, Chikashi; Shimaoka, Toru; Harris, Matthew A; Fu, Gregory L; Kim, Timothy S; Dori, Yoav; McGarvey, Jeremy; Litt, Harold; Bouma, Wobbe; Zsido, Gerald; Glatz, Andrew C; Rome, Jonathan J; Gorman, Robert C; Gorman, Joseph H; Gillespie, Matthew J

2016-10-01

Pulmonary insufficiency is the nexus of late morbidity and mortality after transannular patch repair of tetralogy of Fallot. This study aimed to establish the feasibility of implantation of the novel Medtronic Harmony transcatheter pulmonary valve (hTPV) and to assess its effect on pulmonary insufficiency and ventricular function in an ovine model of chronic postoperative pulmonary insufficiency. Thirteen sheep underwent baseline cardiac magnetic resonance imaging, surgical pulmonary valvectomy, and transannular patch repair. One month after transannular patch repair, the hTPV was implanted, followed by serial magnetic resonance imaging and computed tomography imaging at 1, 5, and 8 month(s). hTPV implantation was successful in 11 animals (85%). There were 2 procedural deaths related to ventricular fibrillation. Seven animals survived the entire follow-up protocol, 5 with functioning hTPV devices. Two animals had occlusion of hTPV with aneurysm of main pulmonary artery. A strong decline in pulmonary regurgitant fraction was observed after hTPV implantation (40.5% versus 8.3%; P=0.011). Right ventricular end diastolic volume increased by 49.4% after transannular patch repair (62.3-93.1 mL/m 2 ; P=0.028) but was reversed to baseline values after hTPV implantation (to 65.1 mL/m 2 at 8 months, P=0.045). Both right ventricular ejection fraction and left ventricular ejection fraction were preserved after hTPV implantation. hTPV implantation is feasible, significantly reduces pulmonary regurgitant fraction, facilitates right ventricular volume improvements, and preserves biventricular function in an ovine model of chronic pulmonary insufficiency. This percutaneous strategy could potentially offer an alternative for standard surgical pulmonary valve replacement in dilated right ventricular outflow tracts, permitting lower risk, nonsurgical pulmonary valve replacement in previously prohibitive anatomies. © 2016 American Heart Association, Inc.

A meta-analysis of manual versus remote magnetic navigation for ventricular tachycardia ablation.

PubMed

Turagam, Mohit K; Atkins, Donita; Tung, Roderick; Mansour, Moussa; Ruskin, Jeremy; Cheng, Jie; Di Biase, Luigi; Natale, Andrea; Lakkireddy, Dhanunjaya

2017-09-01

There are limited studies on the safety and efficacy of remote magnetic navigation (RMN) versus manual navigation (MAN) in ventricular tachycardia (VT) ablation. A comprehensive literature search was performed using the keywords VT ablation, stereotaxis, RMN and MAN in Pubmed, Ebsco, Web of Science, Cochrane, and Google scholar databases. The analysis included seven studies (one randomized, three prospective observational, and three retrospective) including 779 patients [both structural heart disease (SHD) and idiopathic VT] comparing RMN (N = 433) and MAN (N = 339) in VT ablation. The primary end point of long-term VT recurrence was significantly lower with RMN (OR 0.61, 95% CI 0.44-0.85, p = 0.003) compared with MAN. Other end points of acute procedural success (OR 2.13, 95% CI 1.40-3.23, p = 0.0004) was significantly higher with RMN compared with MAN. Fluoroscopy [mean difference -10.42, 95% CI -12.7 to -8.1, p < 0.0001], procedural time [mean difference -9.79, 95% CI -19.27 to -0.3, p = 0.04] and complications (OR 0.35, 95% CI 0.17-0.74, p = 0.0006) were also significantly lower in RMN when compared with MAN. In a subgroup analysis SHD, there was no significant difference in VT recurrence or acute procedural success with RMN vs. MAN. In idiopathic VT, RMN significantly increased acute procedural success with no difference in VT recurrence. The results demonstrate that RMN is safe and effective when compared with MAN in patients with both SHD and idiopathic VT undergoing catheter ablation. Further prospective studies are needed to further verify the safety and efficacy of RMN.

Idiopathic Hypersomnia: A Study of 77 Cases

PubMed Central

Anderson, Kirstie N.; Pilsworth, Samantha; Sharples, Linda D.; Smith, Ian E.; Shneerson, John M.

2007-01-01

Study Objectives: To review the clinical and polysomnographic characteristics of idiopathic hypersomnia as well as the long-term response to treatment. Setting: The Respiratory Support and Sleep Centre at Papworth Hospital, Cambridge, UK. Patients and Design: A large database of more than 6000 patients with sleep disorders was reviewed. A retrospective study of the clinical and polysomnographic characteristics of 77 patients with idiopathic hypersomnia was performed. Comparison with a similar group of patients with narcolepsy was performed. The response to drug treatment was assessed in 61 patients over a mean follow-up of 3.8 years. Measurements and Results: Idiopathic hypersomnia was 60% as prevalent as narcolepsy. Comparison with a similar group of patients with narcolepsy showed that those with idiopathic hypersomnia were more likely to have prolonged unrefreshing daytime naps, a positive family history, increased slow-wave sleep, and a longer sleep latency on the Multiple Sleep Latency Test. The results of the Multiple Sleep Latency Test were not helpful in predicting disease severity or treatment response. The clinical features were heterogeneous and of variable severity. The majority of patients with idiopathic hypersomnia had symptoms that remained stable over many years, but 11% had spontaneous remission, which was never seen in narcolepsy. Two thirds of patients with idiopathic hypersomnolence had a sustained improvement in daytime somnolence with medication, although a third needed high doses or combinations of drugs. Conclusions: Idiopathic hypersomnolence has characteristic clinical and polysomnographic features but the prolonged latency on the Multiple Sleep Latency Test raises doubt about the validity of this test within the current diagnostic criteria. The disease often responds well to treatment and a substantial minority of patients appear to spontaneously improve. Citation: Anderson KN; Pilsworth S; Sharples LD; Smith IE; Shneerson JM. Idiopathic

Ultrafast Hydrogen-Bonding Dynamics in Amyloid Fibrils.

PubMed

Pazos, Ileana M; Ma, Jianqiang; Mukherjee, Debopreeti; Gai, Feng

2018-06-08

While there are many studies on the subject of hydrogen bonding dynamics in biological systems, few, if any, have investigated this fundamental process in amyloid fibrils. Herein, we seek to add insight into this topic by assessing the dynamics of a hydrogen bond buried in the dry interface of amyloid fibrils. To prepare a suitable model peptide system for this purpose, we introduce two mutations into the amyloid-forming Aβ(16-22) peptide. The first one is a lysine analog at position 19, which is used to help form structurally homogeneous fibrils, and the second one is an aspartic acid derivative (DM) at position 17, which is intended (1) to be used as a site-specific infrared probe and (2) to serve as a hydrogen-bond acceptor to lysine so that an inter-β-sheet hydrogen bond can be formed in the fibrils. Using both infrared spectroscopy and atomic force microscopy, we show that (1) this mutant peptide indeed forms well defined fibrils, (2) when bulk solvent is removed, there is no detectable water present in the fibrils, (3) infrared results obtained with the DM probe are consistent with a protofibril structure that is composed of two antiparallel β-sheets stacked in a parallel fashion, leading to formation of the expected hydrogen bond. Using two-dimensional infrared spectroscopy, we further show that the dynamics of this hydrogen bond occur on a timescale of ~2.3 ps, which is attributed to the rapid rotation of the -NH3+ group of lysine around its Cε-Nζ bond. Taken together, these results suggest that (1) DM is a useful infrared marker in facilitating structure determination of amyloid fibrils and (2) even in the tightly packed core of amyloid fibrils certain amino acid sidechains can undergo ultrafast motions, hence contributing to the thermodynamic stability of the system.

Approaches to catheter ablation for persistent atrial fibrillation.

PubMed

Verma, Atul; Jiang, Chen-yang; Betts, Timothy R; Chen, Jian; Deisenhofer, Isabel; Mantovan, Roberto; Macle, Laurent; Morillo, Carlos A; Haverkamp, Wilhelm; Weerasooriya, Rukshen; Albenque, Jean-Paul; Nardi, Stefano; Menardi, Endrj; Novak, Paul; Sanders, Prashanthan

2015-05-07

Catheter ablation is less successful for persistent atrial fibrillation than for paroxysmal atrial fibrillation. Guidelines suggest that adjuvant substrate modification in addition to pulmonary-vein isolation is required in persistent atrial fibrillation. We randomly assigned 589 patients with persistent atrial fibrillation in a 1:4:4 ratio to ablation with pulmonary-vein isolation alone (67 patients), pulmonary-vein isolation plus ablation of electrograms showing complex fractionated activity (263 patients), or pulmonary-vein isolation plus additional linear ablation across the left atrial roof and mitral valve isthmus (259 patients). The duration of follow-up was 18 months. The primary end point was freedom from any documented recurrence of atrial fibrillation lasting longer than 30 seconds after a single ablation procedure. Procedure time was significantly shorter for pulmonary-vein isolation alone than for the other two procedures (P<0.001). After 18 months, 59% of patients assigned to pulmonary-vein isolation alone were free from recurrent atrial fibrillation, as compared with 49% of patients assigned to pulmonary-vein isolation plus complex electrogram ablation and 46% of patients assigned to pulmonary-vein isolation plus linear ablation (P=0.15). There were also no significant differences among the three groups for the secondary end points, including freedom from atrial fibrillation after two ablation procedures and freedom from any atrial arrhythmia. Complications included tamponade (three patients), stroke or transient ischemic attack (three patients), and atrioesophageal fistula (one patient). Among patients with persistent atrial fibrillation, we found no reduction in the rate of recurrent atrial fibrillation when either linear ablation or ablation of complex fractionated electrograms was performed in addition to pulmonary-vein isolation. (Funded by St. Jude Medical; ClinicalTrials.gov number, NCT01203748.).