Impact of transforming growth factor-beta1 on atrioventricular node conduction modification by injected autologous fibroblasts in the canine heart.

PubMed

Bunch, T Jared; Mahapatra, Srijoy; Bruce, G Keith; Johnson, Susan B; Miller, Dylan V; Horne, Benjamin D; Wang, Xiao-Li; Lee, Hon-Chi; Caplice, Noel M; Packer, Douglas L

2006-05-30

Atrioventricular (AV) nodal ablation for management of atrial fibrillation (AF) is irreversible and requires permanent pacemaker implantation. We hypothesized that as an alternative, implantation of autologous fibroblasts in the perinodal region would focally modify AV nodal conduction and that this modulation would be enhanced by pretreatment with transforming growth factor-beta1 (TGF-beta1), a stimulant of fibroblasts. Skin biopsies were taken from 12 mongrel dogs, and derived fibroblasts were dissociated and grown in culture for 2 weeks. Multiple injections (0.25 mL) were made through an 8F NOGA catheter along the fast/slow AV nodal pathways as guided by an electroanatomic mapping system. Seven dogs received fibroblasts alone (1x10(6) cells/mL), 7 dogs received TGF-beta1 (5 microg), 4 dogs received fibroblasts and TGF-beta1 (1x10(6) cells/mL+5 microg), and 4 dogs received saline only. AV node function was assessed at baseline and after 4 weeks. Saline (80 mL) with assigned therapy (0.25 mL per injection) was injected into the peri-AV nodal region in each dog. At baseline, the AH interval (66+/-3 ms) and the average RR interval (331+/-17 ms) in pacing-induced AF were similar in each cohort. The increase in AH interval in normal sinus rhythm was longer after fibroblast (23+/-4 versus 5+/-5 ms; P=0.05) and fibroblast plus TGF-beta1 (50+/-5 versus 5+/-5 ms; P<0.001) injections than with saline alone, with similar findings during high right atrium and distal coronary sinus pacing. The AH interval was not significantly increased after TGF-beta1 injections. The AH interval was significantly longer after fibroblast plus TGF-beta1 injections than with either therapy (TGF-beta1 or fibroblasts) alone. The RR interval during AF was increased in dogs that received fibroblasts alone (110+/-36 versus -41+/-34 ms) and to a greater extent with the addition of TGF-beta1 (294+/-108 versus -41+/-34 ms). No AV block was seen in any cohort at 4 weeks. Labeled fibroblasts that expressed vimentin were identified in all dogs that received cell injections at 4 weeks. AV nodal modification can be achieved with injected fibroblasts without the creation of AV block. The effect on AV node conduction is substantially enhanced by pretreatment of fibroblasts with TGF-beta1. These data have therapeutic potential for the management of rapid ventricular rate during AF without pacemaker implantation.

Clinical evaluation of pacemaker automatic capture management and atrioventricular interval extension algorithm.

PubMed

Chen, Ke-ping; Xu, Geng; Wu, Shulin; Tang, Baopeng; Wang, Li; Zhang, Shu

2013-03-01

The present study was to assess the accuracy of automatic atrial and ventricular capture management (ACM and VCM) in determining pacing threshold and the performance of a second-generation automatic atrioventricular (AV) interval extension algorithm for reducing unnecessary ventricular pacing. A total of 398 patients at 32 centres who received an EnPulse dual-chamber pacing/dual-chamber adaptive rate pacing pacemaker (Medtronic, Minneapolis, MN, USA) were enrolled. The last amplitude thresholds as measured by ACM and VCM prior to the 6-month follow-up were compared with manually measured thresholds. Device diagnostics were used to evaluate ACM and VCM and the percentage of ventricular pacing with and without the AV extension algorithm. Modelling was performed to assess longevity gains relating to the use of automaticity features. Atrial and ventricular capture management performed accurately and reliably provided complete capture management in 97% of studied patients. The AV interval extension algorithm reduced the median per cent of right ventricular pacing in patients with sinus node dysfunction from 99.7 to 1.5% at 6-month follow-up and in patients with intermittent AV block (excluding persistent 3° AV block) from 99.9 to 50.2%. On the basis of validated modelling, estimated device longevity could potentially be extended by 1.9 years through the use of the capture management and AV interval extension features. Both ACM and VCM features reliably measured thresholds in nearly all patients; the AV extension algorithm significantly reduced ventricular pacing; and the use of pacemaker automaticity features potentially extends device longevity.

Anatomical and neurohistological observations on the heart of the rose ringed parakeet, Psittacula krameri.

PubMed

Qayyum, M A; Shaad, F U

1976-01-01

Anatomy, histology and innervation of the heart of the rose ringed parakeet, Psittacula krameri have been studied in the present investigation. The sinuatrial node is found to be well-developed. It is located towards the right side of the cephalic end of the interatrial septum and composed of a few nucleated cells and a large fibrous mass. The atrioventricular node is poorly defined, present at the caudal end of the interatrial septum. The node is somewhat triangular in shape and is composed of elongated and multinucleated specialized fibres. The node is not covered by any connective tissue sheath. The poor development of the atrio ventricular node and the absence of any sheath around it may be correlated with the fast rate of the heart beat. The atrioventricular bundle is observed at the cephalic end of the interventricular septum. A branch from the right limb of the atrioventricular bundle is noted to pass directly into the right atrioventricular valve. The heart is richly innervated. Ganglion cells along with nerve fibres have been observed at the sulcus terminalis and the atrioventricular junction. A direct nervous connection could be observed between the sinuatrial and atrioventricular nodes. It is argued that the impulse which originates in the sinuatrial node would reach the atrioventricular node through the unspecialized muscle fibres and nerve fibres of the interatrial septum. Nerve cells could not be traced in the substance of the sinuatrial node, atrioventricular node and atrioventricular bundle.

Atrioventricular block, ECG tracing (image)

MedlinePlus

... an abnormal rhythm (arrhythmia) called an atrioventricular (AV) block. P waves show that the top of the ... wave (and heart contraction), there is an atrioventricular block, and a very slow pulse (bradycardia).

[Complete atrioventricular block in Duchenne muscular dystrophy].

PubMed

Kuru, Satoshi; Tanahashi, Tamotsu; Matsumoto, Shinjirou; Kitamura, Tetsuya; Konagaya, Masaaki

2012-01-01

We report a case of complete atrioventricular (AV) block in a 40-year-old patient with Duchenne muscular dystrophy (DMD). While he was bed-ridden and required mechanical ventilation, his cardiac involvement was mild. He had the deletion of exon 45-52 in the dystrophin gene. He underwent transient complete AV block and came to require pacemaker implantation due to recurrence of complete AV block ten days after the first attack. Electrophysiological study revealed mild prolonged AH and HV interval. Although DMD patients with AV block have been rarely reported so far, attention should be paid to AV block for patients who prolonged their lives.

Electrocardiographic characteristics of atrioventricular block induced by tilt testing.

PubMed

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

2009-02-01

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

Atrioventricular and intraventricular block after transcatheter aortic valve implantation.

PubMed

Lee, Jane J; Goldschlager, Nora; Mahadevan, Vaikom S

2018-06-24

Aortic stenosis is the most common valvular heart disease in industrialized countries and the most common cause of left ventricular outflow tract (LVOT) obstruction. Transcatheter aortic valve replacement (TAVR) is an alternative to surgical aortic valve replacement for intermediate to high-risk surgical candidates with symptomatic severe aortic stenosis. Conduction system abnormalities, including atrioventricular (AV) and intraventricular (IV) block, are the most common complication of TAVR. In this review, we aim to explore the anatomical issues relevant to atrioventricular block, the relevant clinical and procedural aspects, and the management and long-term implications of AV and IV block.

[Parahisian atrial tachycardia or atrioventricular nodal reentrant tachycardia with tendon of Todaro breakthrough?].

PubMed

Orczykowski, Michał; Jaworska-Wilczyńska, Maria; Urbanek, Piotr; Bodalski, Robert; Derejko, Paweł; Gajek, Jacek; Hryniewiecki, Tomasz; Szumowski, Lukasz; Walczak, Franciszek

2010-08-01

We present a case of a 61 year-old woman with tachycardia originating close to the His bundle where radiofrequency (RF) ablation may bear potential risk of atrioventricular (AV) block. In this case report we discuss the possibility of a AV nodal reciprocating tachycardia with tendon of Todaro breakthrough. Patient was safely and effectively treated with RF catheter ablation.

Second-degree atrioventricular block.

PubMed

Zipes, D P

1979-09-01

1) While it is possible only one type of second-degree AV block exists electrophysiologically, the available data do not justify such a conclusion and it would seem more appropriate to remain a "splitter," and advocate separation and definition of multiple mechanisms, than to be a "lumper," and embrace a unitary concept. 2) The clinical classification of type I and type II AV block, based on present scalar electrocardiographic criteria, for the most part accurately differentiates clinically important categories of patients. Such a classification is descriptive, but serves a useful function and should be preserved, taking into account the caveats mentioned above. The site of block generally determines the clinical course for the patient. For most examples of AV block, the type I and type II classification in present use is based on the site of block. Because block in the His-Purkinje system is preceded by small or nonmeasurable increments, it is called type II AV block; but the very fact that it is preceded by small increments is because it occurs in the His-Purkinje system. Similar logic can be applied to type I AV block in the AV node. Exceptions do occur. If the site of AV block cannot be distinguished with certainity from the scalar ECG, an electrophysiologic study will generally reveal the answer.

Successful catheter ablation of ventricular premature complexes from the right atrial side of the atrioventricular septum with good contact force.

PubMed

Arai, Marina; Fukamizu, Seiji; Kawamura, Iwanari; Miyazawa, Satoshi; Hojo, Rintaro; Sakurada, Harumizu; Hiraoka, Masayasu

2018-04-01

The acquisition of good contact force for radiofrequency catheter ablation of ventricular premature complexes (VPCs) originating from the basal septum of the left ventricle (LV) is often difficult. We describe a case of VPCs originating from the basal septum of the LV, which were successfully eliminated by applying radiofrequency at the right atrium (RA) side of the atrioventricular septum (AVS) without causing any significant impairment of atrioventricular conduction because the ablation catheter could obtain better contact force through the RA approach. Moreover, intracardiac echocardiography (ICE) and RA angiography effectively demonstrated the AVS.

Specificity and effector mechanisms of autoantibodies in congenital heart block.

PubMed

Wahren-Herlenius, Marie; Sonesson, Sven-Erik

2006-12-01

Complete congenital atrio-ventricular (AV) heart block develops in 2-5% of fetuses of Ro/SSA and La/SSB autoantibody-positive pregnant women. During pregnancy, the Ro/SSA and La/SSB antibodies are transported across the placenta and affect the fetus. Emerging data suggest that this happens by a two-stage process. In the first step, maternal autoantibodies bind fetal cardiomyocytes, dysregulate calcium homestasis and induce apoptosis in affected cells. This step might clinically correspond to a first-degree heart block, and be reversible. La/SSB antibodies can bind apoptotic cardiomyocytes and thus increase Ig deposition in the heart. The tissue damage could, as a second step, lead to spread of inflammation in genetically pre-disposed fetuses, progressing to fibrosis and calcification of the AV-node and subsequent complete congenital heart block. Early intrauterine treatment of an incomplete AV-block with fluorinated steroids has been shown to prevent progression of the heart block, making it clinically important to find specific markers to identify the high-risk pregnancies.

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

PubMed Central

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

1986-01-01

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

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

PubMed

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

1986-09-01

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

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

PubMed

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

2001-07-01

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

Diastolic mitral and tricuspid regurgitation by Doppler echocardiography in patients with atrioventricular block: new insight into the mechanism of atrioventricular valve closure.

PubMed

Schnittger, I; Appleton, C P; Hatle, L K; Popp, R L

1988-01-01

The purpose of this study was to prospectively determine the incidence of diastolic mitral and tricuspid regurgitation in atrioventricular (AV) block using Doppler echocardiography. The temporal relation between mitral and tricuspid diastolic insufficiency and the diastolic murmur recorded in patients with complete heart block was also investigated. Twenty-two consecutive patients with AV block (referred to the Echo-Doppler laboratory for routine clinical studies), aged 18 to 87 years, were enrolled in the study. Eleven patients had third degree AV block and a ventricular-inhibited (VVI) pacemaker, two patients had second degree AV block, seven patients had first degree AV block, one patient had blocked premature atrial complexes and one patient had atrial flutter with 4:1 AV block. Diastolic mitral regurgitation was detected in 20 patients, and diastolic tricuspid regurgitation in 21. A mid-diastolic murmur was detected in all patients except in the three youngest. The murmur occurred before diastolic regurgitation and coincided with peak forward flow through the AV valve after atrial contraction. M-mode mitral valve echocardiograms obtained in nine patients demonstrated near closure of some portions of the mitral valve after atrial contraction. Effective closure of the valve, however, did not occur unless ventricular systole supervened. In conclusion, diastolic mitral and tricuspid regurgitation are almost universally present in patients with AV block and are associated with a diastolic murmur. The murmur coincides with forward AV valve flow. Diastolic regurgitation is silent. Effective AV valve closure is not established until ventricular systole occurs, as demonstrated by M-mode echocardiographic recording of the mitral valve.

Modelling the heart with the atrioventricular plane as a piston unit.

PubMed

Maksuti, Elira; Bjällmark, Anna; Broomé, Michael

2015-01-01

Medical imaging and clinical studies have proven that the heart pumps by means of minor outer volume changes and back-and-forth longitudinal movements in the atrioventricular (AV) region. The magnitude of AV-plane displacement has also shown to be a reliable index for diagnosis of heart failure. Despite this, AV-plane displacement is usually omitted from cardiovascular modelling. We present a lumped-parameter cardiac model in which the heart is described as a displacement pump with the AV plane functioning as a piston unit (AV piston). This unit is constructed of different upper and lower areas analogous with the difference in the atrial and ventricular cross-sections. The model output reproduces normal physiology, with a left ventricular pressure in the range of 8-130 mmHg, an atrial pressure of approximatly 9 mmHg, and an arterial pressure change between 75 mmHg and 130 mmHg. In addition, the model reproduces the direction of the main systolic and diastolic movements of the AV piston with realistic velocity magnitude (∼10 cm/s). Moreover, changes in the simulated systolic ventricular-contraction force influence diastolic filling, emphasizing the coupling between cardiac systolic and diastolic functions. The agreement between the simulation and normal physiology highlights the importance of myocardial longitudinal movements and of atrioventricular interactions in cardiac pumping. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Visualizing anatomical evidences on atrioventricular conduction system for TAVI.

PubMed

Kawashima, Tomokazu; Sato, Fumi

2014-06-01

Visualizing the anatomy of the atrioventricular (AV) conduction axis substantiates that there is remarkable inter-individual variation at the macro- and microscopic levels, and that the atrioventricular bundle and left bundle branch are located more anteriorly, distally, and cranially and much closer to the aortic root complex than previously thought. The AV conduction system may therefore be compromised during implantation of a transcatheter aortic valve prosthesis, which may account for the relatively high incidence of new cardiac conduction abnormalities when conventional prosthetic valves are used. The design of the newer JenaValve® may afford advantages over more conventional valves by avoiding the high-risk implantation area and the potential for coronary ostia obstruction. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Atrioventricular valve repair in patients with single-ventricle physiology: mechanisms, techniques of repair, and clinical outcomes.

PubMed

Honjo, Osami; Mertens, Luc; Van Arsdell, Glen S

2011-01-01

Significant atrioventricular (AV) valve insufficiency in patient with single ventricle-physiology is strongly associated with poor survival. Herein we discuss the etiology and mechanism of development of significant AV valve insufficiency in patients with single-ventricle physiology, surgical indication and repair techniques, and clinical outcomes along with our 10-year surgical experience. Our recent clinical series and literature review indicate that it is of prime importance to appreciate the high incidence and clinical effect of the structural abnormalities of AV valve. Valve repair at stage II palliation may minimize the period of volume overload, thereby potentially preserving post-repair ventricular function. Since 85% of the AV valve insufficiency was associated with structural abnormalities, inspection of an AV valve that has more than mild to moderate insufficiency is recommended because they are not likely to be successfully treated with volume unloading surgery alone. Copyright © 2011 Elsevier Inc. All rights reserved.

Three-Dimensional Computer Model of the Right Atrium Including the Sinoatrial and Atrioventricular Nodes Predicts Classical Nodal Behaviours

PubMed Central

Li, Jue; Inada, Shin; Schneider, Jurgen E.; Zhang, Henggui; Dobrzynski, Halina; Boyett, Mark R.

2014-01-01

The aim of the study was to develop a three-dimensional (3D) anatomically-detailed model of the rabbit right atrium containing the sinoatrial and atrioventricular nodes to study the electrophysiology of the nodes. A model was generated based on 3D images of a rabbit heart (atria and part of ventricles), obtained using high-resolution magnetic resonance imaging. Segmentation was carried out semi-manually. A 3D right atrium array model (∼3.16 million elements), including eighteen objects, was constructed. For description of cellular electrophysiology, the Rogers-modified FitzHugh-Nagumo model was further modified to allow control of the major characteristics of the action potential with relatively low computational resource requirements. Model parameters were chosen to simulate the action potentials in the sinoatrial node, atrial muscle, inferior nodal extension and penetrating bundle. The block zone was simulated as passive tissue. The sinoatrial node, crista terminalis, main branch and roof bundle were considered as anisotropic. We have simulated normal and abnormal electrophysiology of the two nodes. In accordance with experimental findings: (i) during sinus rhythm, conduction occurs down the interatrial septum and into the atrioventricular node via the fast pathway (conduction down the crista terminalis and into the atrioventricular node via the slow pathway is slower); (ii) during atrial fibrillation, the sinoatrial node is protected from overdrive by its long refractory period; and (iii) during atrial fibrillation, the atrioventricular node reduces the frequency of action potentials reaching the ventricles. The model is able to simulate ventricular echo beats. In summary, a 3D anatomical model of the right atrium containing the cardiac conduction system is able to simulate a wide range of classical nodal behaviours. PMID:25380074

Three-dimensional echocardiography of congenital abnormalities of the left atrioventricular valve.

PubMed

Rice, Kathryn; Simpson, John

2015-03-01

Congenital abnormalities of the left atrioventricular (AV) valve are a significant diagnostic challenge. Traditionally, reliance has been placed on two-dimensional echocardiographic (2DE) imaging to guide recognition of the specific morphological features. Real-time 3DE can provide unique views of the left AV valve with the potential to improve understanding of valve morphology and function to facilitate surgical planning. This review illustrates the features of congenital abnormalities of the left AV valve assessed by 3DE. The similarities and differences in morphology between different lesions are described, both with respect to the valve itself and supporting chordal apparatus. The potential advantages as well as limitations of this technique in clinical practice are outlined.

Transitions in early embryonic atrioventricular valvular function correspond with changes in cushion biomechanics that are predictable by tissue composition.

PubMed

Butcher, Jonathan T; McQuinn, Tim C; Sedmera, David; Turner, Debi; Markwald, Roger R

2007-05-25

Endocardial cushions are critical to maintain unidirectional blood flow under constantly increasing hemodynamic forces, but the interrelationship between endocardial cushion structure and the mechanics of atrioventricular junction function is poorly understood. Atrioventricular (AV) canal motions and blood velocities of embryonic chicks at Hamburger and Hamilton (HH) stages 17, 21, and 25 were quantified using ultrasonography. Similar to the embryonic zebrafish heart, the HH17 AV segment functions like a suction pump, with the cushions expanding in a wave during peak myocardial contraction and becoming undetectable during the relaxation phase. By HH25, the AV canal contributes almost nothing to the piston-like propulsion of blood, but the cushions function as stoppers apposing blood flow with near constant thickness. Using a custom built mesomechanical testing system, we quantified the nonlinear pseudoelastic biomechanics of developing AV cushions, and found that both AV cushions increased in effective modulus between HH17 and HH25. Enzymatic digestion of major structural constituent collagens or glycosaminoglycans resulted in distinctly different stress-strain curves suggestive of their individual contributions. Mixture theory using histologically determined volume fractions of cells, collagen, and glycosaminoglycans showed good prediction of cushion material properties regardless of stage and cushion position. These results have important implications in valvular development, as biomechanics may play a larger role in stimulating valvulogenic events than previously thought.

Three-dimensional echocardiography of congenital abnormalities of the left atrioventricular valve

PubMed Central

Rice, Kathryn

2015-01-01

Congenital abnormalities of the left atrioventricular (AV) valve are a significant diagnostic challenge. Traditionally, reliance has been placed on two-dimensional echocardiographic (2DE) imaging to guide recognition of the specific morphological features. Real-time 3DE can provide unique views of the left AV valve with the potential to improve understanding of valve morphology and function to facilitate surgical planning. This review illustrates the features of congenital abnormalities of the left AV valve assessed by 3DE. The similarities and differences in morphology between different lesions are described, both with respect to the valve itself and supporting chordal apparatus. The potential advantages as well as limitations of this technique in clinical practice are outlined. PMID:26693328

Fatal Lyme carditis and endodermal heterotopia of the atrioventricular node.

PubMed Central

Cary, N. R.; Fox, B.; Wright, D. J.; Cutler, S. J.; Shapiro, L. M.; Grace, A. A.

1990-01-01

A fatal case of Lyme carditis occurring in a Suffolk farmworker is reported. Post-mortem examination of the heart showed pericarditis, focal myocarditis and prominent endocardial and interstitial fibrosis. The additional finding of endodermal heterotopia ('mesothelioma') of the atrioventricular node raises the possibility that this could also be related to Lyme infection and account for the relatively frequent occurrence of atrioventricular block in this condition. Lyme disease should always be considered in a case of atrioventricular block, particularly in a young patient from a rural area. The heart block tends to improve and therefore only temporary pacing may be required. Images Figure 1 Figure 2 Figure 3 PMID:2349186

Programming Cardiac Resynchronization Therapy for Electrical Synchrony: Reaching Beyond Left Bundle Branch Block and Left Ventricular Activation Delay.

PubMed

Varma, Niraj; O'Donnell, David; Bassiouny, Mohammed; Ritter, Philippe; Pappone, Carlo; Mangual, Jan; Cantillon, Daniel; Badie, Nima; Thibault, Bernard; Wisnoskey, Brian

2018-02-06

QRS narrowing following cardiac resynchronization therapy with biventricular (BiV) or left ventricular (LV) pacing is likely affected by patient-specific conduction characteristics (PR, qLV, LV-paced propagation interval), making a universal programming strategy likely ineffective. We tested these factors using a novel, device-based algorithm (SyncAV) that automatically adjusts paced atrioventricular delay (default or programmable offset) according to intrinsic atrioventricular conduction. Seventy-five patients undergoing cardiac resynchronization therapy (age 66±11 years; 65% male; 32% with ischemic cardiomyopathy; LV ejection fraction 28±8%; QRS duration 162±16 ms) with intact atrioventricular conduction (PR interval 194±34, range 128-300 ms), left bundle branch block, and optimized LV lead position were studied at implant. QRS duration (QRSd) reduction was compared for the following pacing configurations: nominal simultaneous BiV (Mode I: paced/sensed atrioventricular delay=140/110 ms), BiV+SyncAV with 50 ms offset (Mode II), BiV+SyncAV with offset that minimized QRSd (Mode III), or LV-only pacing+SyncAV with 50 ms offset (Mode IV). The intrinsic QRSd (162±16 ms) was reduced to 142±17 ms (-11.8%) by Mode I, 136±14 ms (-15.6%) by Mode IV, and 132±13 ms (-17.8%) by Mode II. Mode III yielded the shortest overall QRSd (123±12 ms, -23.9% [ P <0.001 versus all modes]) and was the only configuration without QRSd prolongation in any patient. QRS narrowing occurred regardless of QRSd, PR, or LV-paced intervals, or underlying ischemic disease. Post-implant electrical optimization in already well-selected patients with left bundle branch block and optimized LV lead position is facilitated by patient-tailored BiV pacing adjusted to intrinsic atrioventricular timing using an automatic device-based algorithm. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Cardiorespiratory interactions in patients with atrial flutter.

PubMed

Masè, Michela; Disertori, Marcello; Ravelli, Flavia

2009-01-01

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

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

PubMed

Hamela-Olkowska, Anita; Dangel, Joanna

2009-08-01

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

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

PubMed

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

2018-04-01

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

Three Dimensional Visualization of Human Cardiac Conduction Tissue in Whole Heart Specimens by High-Resolution Phase-Contrast CT Imaging Using Synchrotron Radiation.

PubMed

Shinohara, Gen; Morita, Kiyozo; Hoshino, Masato; Ko, Yoshihiro; Tsukube, Takuro; Kaneko, Yukihiro; Morishita, Hiroyuki; Oshima, Yoshihiro; Matsuhisa, Hironori; Iwaki, Ryuma; Takahashi, Masashi; Matsuyama, Takaaki; Hashimoto, Kazuhiro; Yagi, Naoto

2016-11-01

The feasibility of synchrotron radiation-based phase-contrast computed tomography (PCCT) for visualization of the atrioventricular (AV) conduction axis in human whole heart specimens was tested using four postmortem structurally normal newborn hearts obtained at autopsy. A PCCT imaging system at the beamline BL20B2 in a SPring-8 synchrotron radiation facility was used. The PCCT imaging of the conduction system was performed with "virtual" slicing of the three-dimensional reconstructed images. For histological verification, specimens were cut into planes similar to the PCCT images, then cut into 5-μm serial sections and stained with Masson's trichrome. In PCCT images of all four of the whole hearts of newborns, the AV conduction axis was distinguished as a low-density structure, which was serially traceable from the compact node to the penetrating bundle within the central fibrous body, and to the branching bundle into the left and right bundle branches. This was verified by histological serial sectioning. This is the first demonstration that visualization of the AV conduction axis within human whole heart specimens is feasible with PCCT. © The Author(s) 2016.

Reduced intrinsic heart rate is associated with reduced arrhythmic susceptibility in guinea-pig heart.

PubMed

Osadchii, Oleg E

2014-12-01

In the clinical setting, patients with slower resting heart rate are less prone to cardiovascular death compared with those with elevated heart rate. However, electrophysiological adaptations associated with reduced cardiac rhythm have not been thoroughly explored. In this study, relationships between intrinsic heart rate and arrhythmic susceptibility were examined by assessments of action potential duration (APD) rate adaptation and inducibility of repolarization alternans in sinoatrial node (SAN)-driven and atrioventricular (AV)-blocked guinea-pig hearts perfused with Langendorff apparatus. Electrocardiograms, epicardial monophasic action potentials, and effective refractory periods (ERP) were assessed in normokalemic and hypokalemic conditions. Slower basal heart rate in AV-blocked hearts was associated with prolonged ventricular repolarization during spontaneous beating, and with attenuated APD shortening at increased cardiac activation rates during dynamic pacing, when compared with SAN-driven hearts. During hypokalemic perfusion, the inducibility of repolarization alternans and tachyarrhythmia by rapid pacing was found to be lower in AV-blocked hearts. This difference was ascribed to prolonged ERP in the setting of reduced basal heart rate, which prevented ventricular capture at critically short pacing intervals required to induce arrhythmia. Reduced basal heart rate is associated with electrophysiological changes that prevent electrical instability upon an abrupt cardiac acceleration.

Recovery of Ventriculo-Atrial Conduction after Adrenaline in Patients Implanted with Pacemakers.

PubMed

Cismaru, Gabriel; Gusetu, Gabriel; Muresan, Lucian; Rosu, Radu; Andronache, Marius; Matuz, Roxana; Puiu, Mihai; Mester, Petru; Miclaus, Maria; Pop, Dana; Mircea, Petru Adrian; Zdrenghea, Dumitru

2015-07-01

Ventriculo-atrial (VA) conduction can have negative consequences for patients with implanted pacemakers and defibrillators. There is concern whether impaired VA conduction could recover during stressful situations. Although the influence of isoproterenol and atropine are well established, the effect of adrenaline has not been studied systematically. The objective of this study was to determine if adrenaline can facilitate recovery of VA conduction in patients implanted with pacemakers. A prospective study was conducted on 61 consecutive patients during a 4-month period (April-July 2014). The presence of VA conduction was assessed during the pacemaker implantation procedure. In case of an impaired VA conduction, adrenaline infusio was used as a stress surrogate to test conduction recovery. The indications for pacemaker implantation were: sinus node dysfunction in 18 patients, atrioventricular (AV) block in 40 patients, binodal dysfunction (sinus node+ AV node) in two patients and other (carotid sinus syndrome) in one patient. In the basal state, 15/61 (24.6%) presented spontaneous VA conduction and 46/61 (75.4%) had no VA conduction. After administration of adrenaline, there was VA conduction recovery in 5/46 (10.9%) patients. Adrenaline infusion produced recovery of VA conduction in 10.9% of patients with absent VA conduction in a basal state. Recovery of VA conduction during physiological or pathological stresses could be responsible for the pacemaker syndrome, PMT episodes, or certain implantable cardiac defibrillator detection issues. © 2015 Wiley Periodicals, Inc.

At the Atrioventricular Crossroads: Dual Pathway Electrophysiology in the Atrioventricular Node and its Underlying Heterogeneities

PubMed Central

George, Sharon A; Faye, N Rokhaya; Murillo-Berlioz, Alejandro; Lee, K Benjamin; Trachiotis, Gregory D; Efimov, Igor R

2017-01-01

The atrioventricular node (AVN) is a complex structure that performs a variety of functions in the heart. The AVN is primarily an electrical gatekeeper between the atria and ventricles and introduces a delay between atrial and ventricular excitation, allowing for efficient ventricular filling. The AVN is composed of several compartments that safely transmit electrical excitation from the atria to the ventricles via the fast or slow pathways. There are many electrophysiological differences between these pathways, including conduction time and electrical refractoriness, that increase the predisposition of the atrioventricular junction to arrhythmias such as atrioventricular nodal re-entrant tachycardia. These varied electrophysiological characteristics of the fast and slow pathways stem from their unique structural and molecular composition (tissue and cellular geometry, ion channels and gap junctions). This review summarises the structural and molecular heterogeneities of the human AVN and how they result in electrophysiological variations and arrhythmias. PMID:29326832

Paroxysmal atrioventricular block: Electrophysiological mechanism of phase 4 conduction block in the His-Purkinje system: A comparison with phase 3 block.

PubMed

Shenasa, Mohammad; Josephson, Mark E; Wit, Andrew L

2017-11-01

Paroxysmal atrioventricular (A-V) block is relatively rare, and due to its transient nature, it is often under recognized. It is often triggered by atrial, junctional, or ventricular premature beats, and occurs in the presence of a diseased His-Purkinje system (HPS). Here, we present a 45-year-old white male who was admitted for observation due to recurrent syncope and near-syncope, who had paroxysmal A-V block. The likely cellular electrophysiological mechanisms(s) of paroxysmal A-V block and its differential diagnosis and management are discussed. Continuous electrocardiographic monitoring was done while the patient was in the cardiac unit. Multiple episodes of paroxysmal A-V block were documented in this case. All episodes were initiated and terminated with atrial/junctional premature beats. The patient underwent permanent pacemaker implantation and has remained asymptomatic since then. Paroxysmal A-V block is rare and often causes syncope or near-syncope. Permanent pacemaker implantation is indicated according to the current guidelines. Paroxysmal A-V block occurs in the setting of diseased HPS and is bradycardia-dependent. The detailed electrophysiological mechanisms, which involve phase 4 diastolic depolarization, and differential diagnosis are discussed. © 2017 Wiley Periodicals, Inc.

Pheochromocytoma-Induced Atrial Tachycardia Leading to Cardiogenic Shock and Cardiac Arrest: Resolution with Atrioventricular Node Ablation and Pacemaker Placement

PubMed Central

Bajaj, Mandeep; Cunningham, Glenn R.

2014-01-01

Pheochromocytoma should be considered in young patients who have acute cardiac decompensation, even if they have no history of hypertension. Atrioventricular node ablation and pacemaker placement should be considered for stabilizing pheochromocytoma patients with cardiogenic shock due to atrial tachyarrhythmias. A 38-year-old black woman presented with cardiogenic shock (left ventricular ejection fraction, <0.15) that did not respond to the placement of an intra-aortic balloon pump. A TandemHeart® Percutaneous Ventricular Assist Device was inserted emergently. After atrioventricular node ablation and placement of a temporary pacemaker, the TandemHeart was removed. Computed tomography of the abdomen revealed a pheochromocytoma. After placement of a permanent pacemaker, the patient underwent a right adrenalectomy. This is, to our knowledge, the first reported case of pheochromocytoma-induced atrial tachyarrhythmia that led to cardiogenic shock and cardiac arrest unresolved by the placement of 2 different ventricular assist devices, but that was completely reversed by radiofrequency ablation of the atrioventricular node and the placement of a temporary pacemaker. We present the patient's clinical, laboratory, and imaging findings, and we review the relevant literature. PMID:25593537

Right heart failure due to loss of right ventricular capture in a patient with atrioventricular junction ablation and biventricular pacing.

PubMed

Raffa, Santi; Fantoni, Cecilia; Restauri, Luigia; Auricchio, Angelo

2005-10-01

We describe the case of a patient with atrioventricular (AV) junction ablation and chronic biventricular pacing in which intermittent dysfunction of the right ventricular (RV) lead resulted in left ventricular (LV) stimulation alone and onset of severe right heart failure. Restoration of biventricular pacing by increasing device output and then performing lead revision resolved the issue. This case provides evidence that LV pacing alone in patients with AV junction ablation may lead to severe right heart failure, most likely as a result of iatrogenic mechanical dyssynchrony within the RV. Thus, probably this pacing mode should be avoided in pacemaker-dependent patients with heart failure.

Sudden death due to the atrioventricular node contusion

PubMed Central

Li, Wenhe; Zhang, Lin; Liang, Yue; Tong, Fang; Zhou, Yiwu

2017-01-01

Abstract Introduction: Atrioventricular node (AVN) contusion usually results in cardiogenic shock and arrhythmia and is a rare but fatal condition. The condition is difficult to diagnose and easily overlooked because it develops rapidly and is asymptomatic. We here report 3 cases that demonstrate blunt chest impact and hemorrhages of the posterior atrioventricular junction, eventually result in death. Clinical Findings: Autopsy and histological examination were performed on all cases. External inspection revealed bruises in the hearts and fractures in the sternum and ribs. However, histological examinations were conclusive and showed cardiac contusion on the surface of the posterior atrioventricular junction of the individuals, and the death was due to the AVN contusion. The position of the AVN on the heart surface is determined by detailed examinations via an autopsy and microscopic, both of which are critical in the certification of cause of death. Conclusion: The report is intended to raise our understanding and make forensic pathologists aware of the surface of the posterior atrioventricular junction. PMID:28072704

New micro waveforms firstly recorded on electrocardiogram in human.

PubMed

Liu, Renguang; Chang, Qinghua; Chen, Juan

2015-10-01

In our study, not only the P-QRS-T waves but also the micro-wavelets before QRS complex (in P wave and PR segment) and after QRS complex (ST segment and upstroke of T wave) were first to be identified on surface electrocardiogram in human by the "new electrocardiogram" machine (model PHS-A10) according to conventional 12-lead electrocardiogram connection methods. By comparison to the conventional electrocardiogram in 100 cases of healthy individuals and several patients with arrhythmias, we have found that the wavelets before P wave theoretically reflected electrical activity of sinus node and the micro-wavelets before QRS complex may be related to atrioventricular conduction system (atrioventricular node, His bundle and bundle branch) potentials. Noninvasive atrioventricular node and His bundle potential tracing will contribute to differentiation of the origin of wide QRS and the location of the atrioventricular block. We also have found that the wavelets after QRS complex may be associated with phase 2 and 3 repolarization of ventricular action potential, which will further reveal ventricular repolarization changes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Increasing T-type calcium channel activity by β-adrenergic stimulation contributes to β-adrenergic regulation of heart rates.

PubMed

Li, Yingxin; Zhang, Xiaoxiao; Zhang, Chen; Zhang, Xiaoying; Li, Ying; Qi, Zhao; Szeto, Christopher; Tang, Mingxin; Peng, Yizhi; Molkentin, Jeffery D; Houser, Steven R; Xie, Mingxing; Chen, Xiongwen

2018-04-01

Cav3.1 T-type Ca 2+ channel current (I Ca-T ) contributes to heart rate genesis but is not known to contribute to heart rate regulation by the sympathetic/β-adrenergic system (SAS). We show that the loss of Cav3.1 makes the beating rates of the heart in vivo and perfused hearts ex vivo, as well as sinoatrial node cells, less sensitive to β-adrenergic stimulation; it also renders less conduction acceleration through the atrioventricular node by β-adrenergic stimulation. Increasing Cav3.1 in cardiomyocytes has the opposite effects. I Ca-T in sinoatrial nodal cells can be upregulated by β-adrenergic stimulation. The results of the present study add a new contribution to heart rate regulation by the SAS system and provide potential new mechanisms for the dysregulation of heart rate and conduction by the SAS in the heart. T-type Ca 2+ channel can be a target for heart disease treatments that aim to slow down the heart rate ABSTRACT: Cav3.1 (α 1G ) T-type Ca 2+ channel (TTCC) is expressed in mouse sinoatrial node cells (SANCs) and atrioventricular (AV) nodal cells and contributes to heart rate (HR) genesis and AV conduction. However, its role in HR regulation and AV conduction acceleration by the β-adrenergic system (SAS) is unclear. In the present study, L- (I Ca-L ) and T-type (I Ca-T ) Ca 2+ currents were recorded in SANCs from Cav3.1 transgenic (TG) and knockout (KO), and control mice. I Ca-T was absent in KO SANCs but enhanced in TG SANCs. In anaesthetized animals, different doses of isoproterenol (ISO) were infused via the jugular vein and the HR was recorded. The EC 50 of the HR response to ISO was lower in TG mice but higher in KO mice, and the maximal percentage of HR increase by ISO was greater in TG mice but less in KO mice. In Langendorff-perfused hearts, ISO increased HR and shortened PR intervals to a greater extent in TG but to a less extent in KO hearts. KO SANCs had significantly slower spontaneous beating rates than control SANCs before and after ISO; TG SANCs had similar basal beating rates as control SANCs probably as a result of decreased I Ca-L but a greater response to ISO than control SANCs. I Ca-T in SANCs was significantly increased by ISO. I Ca-T upregulation by β-adrenergic stimulation contributes to HR and conduction regulation by the SAS. TTCC can be a target for slowing the HR. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

The clinical spectrum of autoimmune congenital heart block

PubMed Central

Brito-Zerón, Pilar; Izmirly, Peter M.; Ramos-Casals, Manuel; Buyon, Jill P.; Khamashta, Munther A.

2017-01-01

Autoimmune congenital heart block (CHB) is an immune-mediated acquired disease that is associated with the placental transference of maternal antibodies specific for Ro and La autoantigens. The disease develops in a fetal heart without anatomical abnormalities that could otherwise explain the block, and which is usually diagnosed in utero, but also at birth or within the neonatal period. Autoantibody-mediated damage of fetal conduction tissues causes inflammation and fibrosis and leads to blockage of signal conduction at the atrioventricular (AV) node. Irreversible complete AV block is the principal cardiac manifestation of CHB, although some babies might develop other severe cardiac complications, such as endocardial fibroelastosis or valvular insufficiency, even in the absence of cardiac block. In this Review, we discuss the epidemiology, classification and management of women whose pregnancies are affected by autoimmune CHB, with a particular focus on the autoantibodies associated with autoimmune CHB and how we should test for these antibodies and diagnose this disease. Without confirmed effective preventive or therapeutic strategies and further research on the aetiopathogenic mechanisms, autoimmune CHB will remain a severe life-threatening disorder. PMID:25800217

MyoR Modulates Cardiac Conduction by Repressing Gata4

PubMed Central

Harris, John P.; Bhakta, Minoti; Bezprozvannaya, Svetlana; Wang, Lin; Lubczyk, Christina; Olson, Eric N.

2014-01-01

The cardiac conduction system coordinates electrical activation through a series of interconnected structures, including the atrioventricular node (AVN), the central connection point that delays impulse propagation to optimize cardiac performance. Although recent studies have uncovered important molecular details of AVN formation, relatively little is known about the transcriptional mechanisms that regulate AV delay, the primary function of the mature AVN. We identify here MyoR as a novel transcription factor expressed in Cx30.2+ cells of the AVN. We show that MyoR specifically inhibits a Cx30.2 enhancer required for AVN-specific gene expression. Furthermore, we demonstrate that MyoR interacts directly with Gata4 to mediate transcriptional repression. Our studies reveal that MyoR contains two nonequivalent repression domains. While the MyoR C-terminal repression domain inhibits transcription in a context-dependent manner, the N-terminal repression domain can function in a heterologous context to convert the Hand2 activator into a repressor. In addition, we show that genetic deletion of MyoR in mice increases Cx30.2 expression by 50% and prolongs AV delay by 13%. Taken together, we conclude that MyoR modulates a Gata4-dependent regulatory circuit that establishes proper AV delay, and these findings may have wider implications for the variability of cardiac rhythm observed in the general population. PMID:25487574

A hybrid surgical transcatheter strategy for treating severe para-right atrioventricular valvular regurgitation in a patient with left atrial isomerism.

PubMed

Kalantre, Atul; Vettukattil, Joseph; Haw, Marcus; Veldtman, Gruschen R

2007-12-01

Paravalvular leaks are a recognized complication of valve replacement surgery. We report a 47-year-old man with left atrial isomerism, interrupted left sided inferior caval vein with unilateral left sided superior caval vein, a common atrium, and anomalous pulmonary venous connection to the coronary sinus, who had recurrent severe para-right atrioventricular (AV) regurgitation with gross right heart failure following tricuspid valve (TCV) replacement. He underwent a hybrid surgery-transcatheter treatment strategy in the cardiac catheterization laboratory, which led to significant improvement in hemodynamics and symptoms. This to our knowledge is the first reported case of a minimally invasive approach to para-right sided AV valve regurgitation.

Atrial flutter with spontaneous 1:1 atrioventricular conduction in adults: an uncommon but frequently missed cause for syncope/presyncope.

PubMed

Turitto, Gioia; Akhrass, Philippe; Leonardi, Marino; Saponieri, Cesare; Sette, Antonella; El-Sherif, Nabil

2009-01-01

To compare patients with atrial flutter (AFl) and 1:1 atrioventricular conduction (AVC) with patients with AFl and higher AVC. The characteristics of 19 patients with AFl and 1:1 AVC (group A) were compared with those of 116 consecutive patients with AFl and 2:1 AVC or higher degree AV block (group B). Age, gender, and left ventricular function were similar in the two groups. In group A versus group B, more patients had no structural heart disease (42% vs 17%, P < 0.05) and syncope/presyncope (90% vs 12%, P < 0.05). The AFl cycle length (CL) in group A was longer than in group B (265 +/- 24 ms vs 241 +/- 26 ms, P < 0.01). The transition from AFl with 1:1 to 2:1 AVC or vice versa was associated with small but definite changes in AFl CL, which showed larger variations in response to sympathetic stimulation. In group A patients who were studied off drugs, the atrial-His interval was not different from group B, but maximal atrial pacing rate with 1:1 AVC was faster. In group A, five patients were misdiagnosed as ventricular tachyarrhythmias, and three with a defibrillator received inappropriate shocks. Four patients had ablation of AVC and six had ablation of AFl circuit. The main difference between groups A and B may be an inherent capacity of the AV node for faster conduction, especially in response to increased sympathetic tone. The latter affects not only AVC but also the AFl CL. One should be aware of the different presentations of AFl with 1:1 AVC to avoid misdiagnosis/mismanagement and to consider the diagnosis in patients with narrow or wide QRS tachycardia and rates above 220/min.

Increased prevalence of third-degree atrioventricular block in patients with type II diabetes mellitus.

PubMed

Movahed, Mohammad-Reza; Hashemzadeh, Mehrtash; Jamal, M Mazen

2005-10-01

Diabetes mellitus (DM) is a major risk for cardiovascular disease and mortality. There is some evidence that third-degree atrioventricular (AV) block occurs more commonly in patients with DM. In this study, we evaluated any possible association between DM and third-degree AV block using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes in a very large inpatient database. We used patient treatment files containing discharge diagnoses using ICD-9 codes of inpatient treatment from all Veterans Health Administration hospitals. The cohort was stratified using the ICD-9-CM code for DM (n = 293,124), a control group with hypertension but no DM (n = 552,623), and the ICD-9 code for third-degree AV block (426.0) and smoking (305.1, V15.82). We performed multivariate analysis adjusting for coronary artery disease, congestive heart failure, smoking, and hyperlipidemia. Continuous and binary variables were analyzed using chi2 and Fisher exact tests. Third-degree AV block diagnosis was present in 3,240 of DM patients (1.1%) vs 3,367 patients (0.6%) in the control group. Using multivariate analysis, DM remained strongly associated with third-degree AV block (odds ratio, 3.1; 95% confidential interval, 3.0 to 3.3; p < 0.0001). Third-degree AV block occurs significantly more in patients with DM. This finding may, in part, explain the high cardiovascular mortality in DM patients.

Complete Atrioventricular Block Complicating Mitral Infective Endocarditis Caused by Streptococcus Agalactiae.

PubMed

Arai, Masaru; Nagashima, Koichi; Kato, Mahoto; Akutsu, Naotaka; Hayase, Misa; Ogura, Kanako; Iwasawa, Yukino; Aizawa, Yoshihiro; Saito, Yuki; Okumura, Yasuo; Nishimaki, Haruna; Masuda, Shinobu; Hirayama, Astushi

2016-09-08

BACKGROUND Infective endocarditis (IE) involving the mitral valve can but rarely lead to complete atrioventricular block (CAVB). CASE REPORT A 74-year-old man with a history of infective endocarditis caused by Streptococcus gordonii (S. gordonii) presented to our emergency room with fever and loss of appetite, which had lasted for 5 days. On admission, results of serologic tests pointed to severe infection. Electrocardiography showed normal sinus rhythm with first-degree atrioventricular block and incomplete right bundle branch block, and transthoracic echocardiography and transesophageal echocardiography revealed severe mitral regurgitation caused by posterior leaflet perforation and 2 vegetations (5 mm and 6 mm) on the tricuspid valve. The patient was initially treated with ceftriaxone and gentamycin because blood and cutaneous ulcer cultures yielded S. agalactiae. On hospital day 2, however, sudden CAVB requiring transvenous pacing occurred, and the patient's heart failure and infection worsened. Although an emergent surgery is strongly recommended, even in patients with uncontrolled heart failure or infection, surgery was not performed because of the Child-Pugh class B liver cirrhosis. Despite intensive therapy, the patient's condition further deteriorated, and he died on hospital day 16. On postmortem examination, a 2×1-cm vegetation was seen on the perforated posterior mitral leaflet, and the infection had extended to the interventricular septum. Histologic examination revealed extensive necrosis of the AV node. CONCLUSIONS This rare case of CAVB resulting from S. agalactiae IE points to the fact that in monitoring patients with IE involving the mitral valve, clinicians should be aware of the potential for perivalvular extension of the infection, which can lead to fatal heart block.

Unexpected delayed complete atrioventricular block after Cardioband implantation.

PubMed

Sorini Dini, Carlotta; Landi, Daniele; Meucci, Francesco; Di Mario, Carlo

2018-03-06

The Cardioband system is a transcatheter direct annuloplasty device that is implanted in patients with severe symptomatic functional mitral regurgitation (MR) due to annulus dilatation and high surgical risk. This device covers the posterior two-thirds of the annulus, from the anterolateral to the posteromedial commissure, implanted in close proximity of the left circumflex artery, atrioventricular (AV) conduction system, and coronary sinus. We present the case of an 80-year-old-gentleman with prohibitive surgical risk, treated with Cardioband implantation for functional MR with an evident P1-P2 cleft and P2-P3 indentation, a relative contraindication to MitraClip implantation. We achieved procedural success with significative mitral annulus reduction (30% anteroposterior reduction from 37 to 26 mm) and MR reduction (from grade 4 to grade 1-2). A late onset Mobitz 2 AV block developed after 26 hr and evolved to complete AV block in the following day, requiring definitive biventricular pacemaker (PM). Less than 200 Cardioband implantations have been performed but, to our knowledge, this is the first reported AV block, possibly facilitated by the pre-existing bifascicular block, suggesting the opportunity of prolonged ECG monitoring after Cardioband like any other mechanical transcatheter structural intervention possibly affecting the AV conduction system. © 2018 Wiley Periodicals, 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.

Nitric Oxide Synthase-3 Promotes Embryonic Development of Atrioventricular Valves

PubMed Central

Liu, Yin; Lu, Xiangru; Xiang, Fu-Li; Lu, Man; Feng, Qingping

2013-01-01

Nitric oxide synthase-3 (NOS3) has recently been shown to promote endothelial-to-mesenchymal transition (EndMT) in the developing atrioventricular (AV) canal. The present study was aimed to investigate the role of NOS3 in embryonic development of AV valves. We hypothesized that NOS3 promotes embryonic development of AV valves via EndMT. To test this hypothesis, morphological and functional analysis of AV valves were performed in wild-type (WT) and NOS3−/− mice at postnatal day 0. Our data show that the overall size and length of mitral and tricuspid valves were decreased in NOS3−/− compared with WT mice. Echocardiographic assessment showed significant regurgitation of mitral and tricuspid valves during systole in NOS3−/− mice. These phenotypes were all rescued by cardiac specific NOS3 overexpression. To assess EndMT, immunostaining of Snail1 was performed in the embryonic heart. Both total mesenchymal and Snail1+ cells in the AV cushion were decreased in NOS3−/− compared with WT mice at E10.5 and E12.5, which was completely restored by cardiac specific NOS3 overexpression. In cultured embryonic hearts, NOS3 promoted transforming growth factor (TGFβ), bone morphogenetic protein (BMP2) and Snail1expression through cGMP. Furthermore, mesenchymal cell formation and migration from cultured AV cushion explants were decreased in the NOS3−/− compared with WT mice. We conclude that NOS3 promotes AV valve formation during embryonic heart development and deficiency in NOS3 results in AV valve insufficiency. PMID:24204893

Reasons for conversion and adverse intraoperative events in Endoscopic Port Access™ atrioventricular valve surgery and minimally invasive aortic valve surgery.

PubMed

van der Merwe, Johan; Van Praet, Frank; Stockman, Bernard; Degrieck, Ivan; Vermeulen, Yvette; Casselman, Filip

2018-02-14

This study reports the factors that contribute to sternotomy conversions (SCs) and adverse intraoperative events in minimally invasive aortic valve surgery (MI-AVS) and minimally invasive Endoscopic Port Access™ atrioventricular valve surgery (MI-PAS). In total, 3780 consecutive patients with either aortic valve disease or atrioventricular valve disease underwent minimally invasive valve surgery (MIVS) at our institution between 1 February 1997 and 31 March 2016. MI-AVS was performed in 908 patients (mean age 69.2 ± 11.3 years, 45.2% women, 6.2% redo cardiac surgery) and MI-PAS in 2872 patients (mean age 64.1 ± 13.3 years, 46.7% women, 12.2% redo cardiac surgery). A cumulative total of 4415 MIVS procedures (MI-AVS = 908, MI-PAS = 3507) included 1537 valve replacements (MI-AVS = 896, MI-PAS = 641) and 2878 isolated or combined valve repairs (MI-AVS = 12, MI-PAS = 2866). SC was required in 3.0% (n = 114 of 3780) of MIVS patients, which occurred in 3.1% (n = 28 of 908) of MI-AVS patients and 3.0% (n = 86 of 2872) of MI-PAS patients, respectively. Reasons for SC in MI-AVS included inadequate visualization (n = 4, 0.4%) and arterial cannulation difficulty (n = 7, 0.8%). For MI-PAS, SC was required in 54 (2.5%) isolated mitral valve procedures (n = 2183). Factors that contributed to SC in MI-PAS included lung adhesions (n = 35, 1.2%), inadequate visualization (n = 2, 0.1%), ventricular bleeding (n = 3, 0.1%) and atrioventricular dehiscence (n = 5, 0.2%). Neurological deficit occurred in 1 (0.1%) and 3 (3.5%) MI-AVS and MI-PAS conversions, respectively. No operative or 30-day mortalities were observed in MI-AVS conversions (n = 28). The 30-day mortality associated with SC in MI-PAS (n = 86) was 10.5% (n = 9). MIVS is increasingly being recognized as the 'gold-standard' for surgical valve interventions in the context of rapidly expanding catheter-based technology and increasing patient expectations. Surgeons need to be aware of factors that contribute to SC and adverse intraoperative outcomes to ensure that patients enjoy the maximum potential benefit of MIVS and to apply effective risk reduction strategies that encourage safer and sustainable MIVS programmes.

Perinatal outcome in fetuses with heterotaxy syndrome and atrioventricular block or bradycardia.

PubMed

Escobar-Diaz, Maria C; Tworetzky, Wayne; Friedman, Kevin; Lafranchi, Terra; Fynn-Thompson, Francis; Alexander, Mark E; Mah, Douglas Y

2014-08-01

Congenital atrioventricular (AV) block is commonly associated with heterotaxy syndrome; together they have reportedly low survival rates (10-25%). However, information about perinatal outcome and predictors of non-survival after prenatal diagnosis of this association is scarce. Therefore, we studied fetuses with heterotaxy syndrome and bradycardia or AV-block diagnosed between 1995 and 2011, and analyzed pre and post-natal variables. The primary outcome was death and the secondary outcome was pacemaker placement. Of the 154 fetuses with heterotaxy syndrome, 91 had polysplenia syndrome, 22/91(24%) with bradycardia or AV-block. Thirteen (59%) patients had sinus bradycardia at diagnosis, 8 (36%) complete AV block, and 1 (5%) second-degree AV-block. Three patients elected for termination of pregnancy (3/22, 14%), 4 had spontaneous fetal demise (4/22, 18%), and 15 (15/22, 68%) were live-born. Of the fetuses with bradycardia/AV-block, 30% presented with hydrops, 20% had ventricular rates <55 beats/min, and 10% had cardiac dysfunction. Excluding termination of pregnancy, 15/19 fetuses (79%) survived to birth. Among the 15 live-born patients, 4 had bradycardia and 11 had AV-block. A further 3 patients died in infancy, all with AV-block who required pacemakers in the neonatal period. Thus, the 1-year survival rate, excluding termination of pregnancy, was 63% (12/19). Of the remaining 12 patients, 9 required pacemaker. Predictors of perinatal death included hydrops (p < 0.0001), ventricular dysfunction (p = 0.002), prematurity (p = 0.04), and low ventricular rates (p = 0.04). In conclusion, we found a higher survival rate (63%) than previously published in patients with heterotaxy syndrome and AV block or bradycardia diagnosed prenatally. Hydrops, cardiac dysfunction, prematurity and low ventricular rates were predictors of death.

Perinatal Outcome in Fetuses with Heterotaxy Syndrome and Atrioventricular Block or Bradycardia

PubMed Central

Tworetzky, Wayne; Friedman, Kevin; Lafranchi, Terra; Fynn-Thompson, Francis; Alexander, Mark E.; Mah, Douglas Y.

2015-01-01

Congenital atrioventricular (AV) block is commonly associated with heterotaxy syndrome; together they have reportedly low survival rates (10–25 %). However, information about perinatal outcome and predictors of nonsurvival after prenatal diagnosis of this association is scarce. Therefore, we studied fetuses with heterotaxy syndrome and bradycardia or AV-block diagnosed between 1995 and 2011, and analyzed pre and post-natal variables. The primary outcome was death and the secondary outcome was pacemaker placement. Of the 154 fetuses with heterotaxy syndrome, 91 had polysplenia syndrome, 22/91(24 %) with bradycardia or AV-block. Thirteen (59 %) patients had sinus bradycardia at diagnosis, 8 (36 %) complete AV block, and 1 (5 %) second-degree AV-block. Three patients elected for termination of pregnancy (3/22, 14 %), 4 had spontaneous fetal demise (4/22, 18 %), and 15 (15/22, 68 %) were live-born. Of the fetuses with bradycardia/AV-block, 30 % presented with hydrops, 20 % had ventricular rates <55 beats/min, and 10 % had cardiac dysfunction. Excluding termination of pregnancy, 15/19 fetuses (79 %) survived to birth. Among the 15 live-born patients, 4 had bradycardia and 11 had AV-block. A further 3 patients died in infancy, all with AV-block who required pacemakers in the neonatal period. Thus, the 1-year survival rate, excluding termination of pregnancy, was 63 % (12/19). Of the remaining 12 patients, 9 required pacemaker. Predictors of perinatal death included hydrops (p < 0.0001), ventricular dysfunction (p = 0.002), prematurity (p = 0.04), and low ventricular rates (p = 0.04). In conclusion, we found a higher survival rate (63 %) than previously published in patients with heterotaxy syndrome and AV block or bradycardia diagnosed prenatally. Hydrops, cardiac dysfunction, prematurity and low ventricular rates were predictors of death. PMID:24509635

Reduction of right ventricular pacing with advanced atrioventricular search hysteresis: results of the PREVENT study.

PubMed

Kolb, Christof; Schmidt, Roland; Dietl, Josef U; Weyerbrock, Sonja; Morgenstern, Martin; Fleckenstein, Martin; Beier, Thomas; Von Bary, Christian; Mackes, Karl G; Widmaier, Jochen; Kreuzer, Jörg; Semmler, Verena; Zrenner, Bernhard

2011-08-01

Right ventricular pacing predisposes to the development of heart failure and atrial fibrillation. Automatic atrioventricular search hysteresis (AVSH) is a commonly used strategy to decrease the percentage of right ventricular pacing (%VP) in patients without permanent AV block, but the results have not been optimal. The randomized, crossover PREVENT study evaluated whether an enhanced AVSH with two new features can reduce %VP compared with standard AVSH. The new features are the repetitive hysteresis [switch from extended to basic AV delay after a consistent loss of intrinsic AV conduction (IAVC) lasting for six consecutive atrial cycles] and the scan hysteresis (periodic IAVC search extension over six consecutive atrial cycles). Both standard AVSH and enhanced AVSH performed a periodic IAVC search every 180 cardiac cycles and operated with a basic AV-delay of 225 ms and a rate-independent maximum AV-delay of 300 ms for paced and sensed atrial events. Among 178 patients, 53.4% had no evidence of AV block at enrollment and 46.6% had history of intermittent AV block. The median %VP was decreased by enhanced AVSH compared to standard AVSH (4.0% vs 5.5%, P < 0.001), particularly in patients with a history of AV block (21.4% vs 25.5%, P < 0.001). The primary study hypothesis that 25% of all patients would experience > 20% relative %VP reduction was not met as 46 (25.8%) patients (95% confidence interval, 20.5-31.8%) presented such relative reduction. The enhanced AVSH algorithm reduces %VP compared with standard AVSH in patients with intermittent AV block. ©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.

Novel insights into the distribution of cardiac HCN channels: an expression study in the mouse heart.

PubMed

Herrmann, Stefan; Layh, Beate; Ludwig, Andreas

2011-12-01

HCN pacemaker channels (I(f) channels) are believed to contribute to important functions in the heart; thus these channels became an attractive target for generating transgenic mouse mutants to elucidate their role in physiological and pathophysiological cardiac conditions. A full understanding of cardiac I(f) and the interpretation of studies using HCN mouse mutants require detailed information about the expression profile of the individual HCN subunits. Here we investigate the cardiac expression pattern of the HCN isoforms at the mRNA as well as at the protein level. The specificity of antibodies used was strictly confirmed by the use of HCN1, HCN2 and HCN4 knockout animals. We find a low, but highly differential HCN expression profile outside the cardiac conduction pathway including left and right atria and ventricles. Additionally HCN distribution was investigated in tissue slices of the sinoatrial node, the atrioventricular node, the bundle of His and the bundle branches. The conduction system was marked by acetylcholine esterase staining. HCN4 was confirmed as the predominant isoform of the primary pacemaker followed by a distinct expression of HCN1. In contrast HCN2 shows only a confined expression to individual pacemaker cells. Immunolabeling of the AV-node reveals also a pronounced specificity for HCN1 and HCN4. Compared to the SN and AVN we found a low but selective expression of HCN4 as the only isoform in the atrioventricular bundle. However in the bundle branches HCN1, HCN4 and also HCN2 show a prominent and selective expression pattern. Our results display a characteristic distribution of individual HCN isoforms in several cardiac compartments and reveal that beside HCN4, HCN1 represents the isoform which is selectively expressed in most parts of the conduction system suggesting a substantial contribution of HCN1 to pacemaking. 2011 Elsevier Ltd. All rights reserved.

Embryonic Ethanol Exposure Dysregulates BMP and Notch Signaling, Leading to Persistent Atrio-Ventricular Valve Defects in Zebrafish

PubMed Central

Sarmah, Swapnalee; Muralidharan, Pooja

2016-01-01

Fetal alcohol spectrum disorder (FASD), birth defects associated with ethanol exposure in utero, includes a wide spectrum of congenital heart defects (CHDs), the most prevalent of which are septal and conotruncal defects. Zebrafish FASD model was used to dissect the mechanisms underlying FASD-associated CHDs. Embryonic ethanol exposure (3–24 hours post fertilization) led to defects in atrio-ventricular (AV) valvulogenesis beginning around 37 hpf, a morphogenetic event that arises long after ethanol withdrawal. Valve leaflets of the control embryos comprised two layers of cells confined at the compact atrio-ventricular canal (AVC). Ethanol treated embryos had extended AVC and valve forming cells were found either as rows of cells spanning the AVC or as unorganized clusters near the AV boundary. Ethanol exposure reduced valve precursors at the AVC, but some ventricular cells in ethanol treated embryos exhibited few characteristics of valve precursors. Late staged larvae and juvenile fish exposed to ethanol during embryonic development had faulty AV valves. Examination of AVC morphogenesis regulatory networks revealed that early ethanol exposure disrupted the Bmp signaling gradient in the heart during valve formation. Bmp signaling was prominent at the AVC in controls, but ethanol-exposed embryos displayed active Bmp signaling throughout the ventricle. Ethanol exposure also led to mislocalization of Notch signaling cells in endocardium during AV valve formation. Normally, highly active Notch signaling cells were organized at the AVC. In ethanol-exposed embryos, highly active Notch signaling cells were dispersed throughout the ventricle. At later stages, ethanol-exposed embryos exhibited reduced Wnt/β-catenin activity at the AVC. We conclude that early embryonic ethanol exposure alters Bmp, Notch and other signaling activities during AVC differentiation leading to faulty valve morphogenesis and valve defects persist in juvenile fish. PMID:27556898

Embryonic Ethanol Exposure Dysregulates BMP and Notch Signaling, Leading to Persistent Atrio-Ventricular Valve Defects in Zebrafish.

PubMed

Sarmah, Swapnalee; Muralidharan, Pooja; Marrs, James A

2016-01-01

Fetal alcohol spectrum disorder (FASD), birth defects associated with ethanol exposure in utero, includes a wide spectrum of congenital heart defects (CHDs), the most prevalent of which are septal and conotruncal defects. Zebrafish FASD model was used to dissect the mechanisms underlying FASD-associated CHDs. Embryonic ethanol exposure (3-24 hours post fertilization) led to defects in atrio-ventricular (AV) valvulogenesis beginning around 37 hpf, a morphogenetic event that arises long after ethanol withdrawal. Valve leaflets of the control embryos comprised two layers of cells confined at the compact atrio-ventricular canal (AVC). Ethanol treated embryos had extended AVC and valve forming cells were found either as rows of cells spanning the AVC or as unorganized clusters near the AV boundary. Ethanol exposure reduced valve precursors at the AVC, but some ventricular cells in ethanol treated embryos exhibited few characteristics of valve precursors. Late staged larvae and juvenile fish exposed to ethanol during embryonic development had faulty AV valves. Examination of AVC morphogenesis regulatory networks revealed that early ethanol exposure disrupted the Bmp signaling gradient in the heart during valve formation. Bmp signaling was prominent at the AVC in controls, but ethanol-exposed embryos displayed active Bmp signaling throughout the ventricle. Ethanol exposure also led to mislocalization of Notch signaling cells in endocardium during AV valve formation. Normally, highly active Notch signaling cells were organized at the AVC. In ethanol-exposed embryos, highly active Notch signaling cells were dispersed throughout the ventricle. At later stages, ethanol-exposed embryos exhibited reduced Wnt/β-catenin activity at the AVC. We conclude that early embryonic ethanol exposure alters Bmp, Notch and other signaling activities during AVC differentiation leading to faulty valve morphogenesis and valve defects persist in juvenile fish.

Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management.

PubMed

Baruteau, Alban-Elouen; Pass, Robert H; Thambo, Jean-Benoit; Behaghel, Albin; Le Pennec, Solène; Perdreau, Elodie; Combes, Nicolas; Liberman, Leonardo; McLeod, Christopher J

2016-09-01

Atrioventricular block is classified as congenital if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive cardiac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe permanent cardiac pacing in almost all patients, including those with structural heart abnormalities. Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current understanding of the pathogenetic mechanisms, clinical course, and optimal management of congenital and childhood AV block. • Prevalence of congenital heart block of 1 per 15,000 to 20,000 live births. AV block is defined as congenital if diagnosed in utero, at birth, or within the first month of life, whereas childhood AV block is diagnosed between the first month and the 18th year of life. As a result of several different etiologies, congenital and childhood atrioventricular block may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Cardiac pacing is indicated in symptomatic patients and has several prophylactic indications in asymptomatic patients to prevent sudden death. • Autoimmune, congenital AV block is associated with a high neonatal mortality rate and development of dilated cardiomyopathy in 5 to 30 % cases. What is New: • Several genes including SCN5A have been implicated in autosomal dominant forms of familial progressive cardiac conduction disorders. • Leadless pacemaker technology and gene therapy for biological pacing are promising research fields. In utero percutaneous pacing appears to be at high risk and needs further development before it can be adopted into routine clinical practice. Cardiac resynchronization therapy is of proven value in case of pacing-induced cardiomyopathy.

Pacemaker mediated tachycardia as a complication of the autointrinsic conduction search function.

PubMed

Dennis, Malcolm J; Sparks, Paul B

2004-06-01

The autointrinsic conduction search (AICS) option, featured on some DDD pacemakers, performs periodic assessments of atrioventricular (AV) conduction capability during a single beat AV delay extension. Demonstration of ventricular conduction during the prolonged AV delay, permits ongoing AV delay extension if the patient's intrinsic conduction is preferred to ventricular pacing. A case is presented where the wide separation of atrial and ventricular pacing during the conduction search permitted retrograde ventriculoatrial conduction, precipitating pacemaker mediated tachycardia (PMT) on seven occasions in one patient. Two onset patterns are reported, both attributable to the AICS option. Recommendations for prevention strategies are made.

Minimizing right ventricular pacing in pacemaker patients with intact and compromised atrioventricular conduction : Results from the EVITA Trial.

PubMed

Bauer, A; Vermeulen, J; Toivonen, L; Voitk, J; Barr, C; Peytchev, P

2015-12-01

Unnecessary ventricular pacing is associated with increased morbidity and mortality. Over the years different algorithms have been developed to reduce right ventricular pacing. Goal of the present study was to test the efficacy of the ventricular intrinsic preference (VIP) algorithm in patients with atrioventricular intact (AVi) and atrioventricular compromised (AVc) AV-conduction. Evaluation of VIP feature in pacemaker patients (EVITA) was a multicenter, prospective, randomized trial (Trials.gov Identifier: NCT00366158). In total, 389 patients were randomized to AVc group: n = 140/132 VIP OFF/VIP On, AVi group: n = 54/63 VIP OFF/VIP ON). One-month post-implantation AV conduction testing (AVc: PR/AR interval > 210 ms) was performed. Follow-up visits occurred 6 and 12 months after DDD-pacemaker implantation. In AVi and AVc-patients initiation of the VIP feature significantly reduced incidence of ventricular pacing (AVi: 53 ± 38 vs. 9 ± 21%, p = 0.0001; AVc: 79 ± 31 vs. 28 ± 35%, p = 0.0001). DDD-pacemaker implantation per se significantly reduced incidence of AF in VIP ON (AVi 27 vs. 0%, p < 0.0001; AVc 29 vs. 3%, p < 0.0001) and VIP OFF patients (AVi 43 vs. 4%, p < 0.0001; AVc 33 vs. 3, p < 0.0001), without significant differences between VIP ON and OFF groups (p > 0.05). In the AVc group activation of VIP significantly reduced incidence of adverse events (AE). All-cause mortality was not significantly different in VIP ON (n = 5) and VIP OFF (n = 4, p > 0.05) patients. AV search hysteresis (VIP) markedly reduces ventricular pacing both in patients with normal AV conduction and in patients with prolonged PR interval or intermittent AV block.

Creation of a genetic calcium channel blocker by targeted gem gene transfer in the heart.

PubMed

Murata, Mitsushige; Cingolani, Eugenio; McDonald, Amy D; Donahue, J Kevin; Marbán, Eduardo

2004-08-20

Calcium channel blockers are among the most commonly used therapeutic drugs. Nevertheless, the utility of calcium channel blockers for heart disease is limited because of the potent vasodilatory effect that causes hypotension, and other side effects attributable to blockade of noncardiac channels. Therefore, focal calcium channel blockade by gene transfer is highly desirable. With a view to creating a focally applicable genetic calcium channel blocker, we overexpressed the ras-related small G-protein Gem in the heart by somatic gene transfer. Adenovirus-mediated delivery of Gem markedly decreased L-type calcium current density in ventricular myocytes, resulting in the abbreviation of action potential duration. Furthermore, transduction of Gem resulted in a significant shortening of the electrocardiographic QTc interval and reduction of left ventricular systolic function. Focal delivery of Gem to the atrioventricular (AV) node significantly slowed AV nodal conduction (prolongation of PR and AH intervals), which was effective in the reduction of heart rate during atrial fibrillation. Thus, these results indicate that gene transfer of Gem functions as a genetic calcium channel blocker, the local application of which can effectively modulate cardiac electrical and contractile function.

Value of local electrogram characteristics predicting successful catheter ablation of left-versus right-sided accessory atrioventricular pathways by radiofrequency current.

PubMed

Lin, J L; Schie, J T; Tseng, C D; Chen, W J; Cheng, T F; Tsou, S S; Chen, J J; Tseng, Y Z; Lien, W P

1995-01-01

Despite similar guidance by local electrogram criteria, catheter ablation of right-sided accessory atrioventricular (AV) pathways by radiofrequency current has been less effective than that of left-sided ones. In order to elucidate the possible diversities in local electrosignal criteria, we systematically analyzed the morphological and timing characteristics of 215 bipolar local electrograms from catheter ablation sites of 65 left-sided accessory AV pathways and of 356 from those of 37 right-sided ones in 92 consecutive patients with Wolff-Parkinson-White syndrome or AV reentrant tachycardia incorporating concealed accessory AV pathways. After stepwise multivariate analysis, we selected the presence of a possible accessory pathway potential, local ventricular activation preceding QRS complex for 20 ms or more during ventricular insertion mapping, and the local retrograde ventriculoatrial (VA) continuity, local retrograde VA interval < or = 50 ms, electrogram stability (left-sided targets only), retrograde accessory pathway potential (right-sided targets only) during atrial insertion mapping, as independent local electrogram predictors for successful ablation of left- and right-sided accessory AV pathways. Combination of all local electrogram predictors could have moderate chance of success (80 and 51%) for the ventricular and atrial insertion ablation of left-sided accessory AV pathways, but only low probability of success (40% in ventricular insertion ablation) or very low sensitivity (12.5% in atrial insertion ablation) for right-sided ones. In conclusion, with the present approach, successful catheter ablation of right-sided accessory AV pathways, compared to left-sided ones, still necessitate a breakthrough in the precision mapping and the efficiency of energy delivery.

Second diastolic pulmonary venous flow and isolated late diastolic mitral valve regurgitation in first-degree atrioventricular block.

PubMed

Leibundgut, Gregor; Bernheim, Alain M

2010-04-01

The authors report the case of a 77-year-old male patient with sinus rhythm and a first-degree atrioventricular (AV) block who was referred for echocardiographic follow-up 18 years after aortic valve replacement. Left ventricular systolic function as well as the function of the aortic prosthesis was normal. Systolic mitral regurgitation (MR) was virtually absent, but isolated late diastolic MR was detected by colour Doppler imaging. Coincidental to the occurrence of diastolic MR, a second late diastolic forward flow in the pulmonary veins was observed. Therefore, during the prolonged left atrial relaxation caused by first-degree AV block, the left atrial pressure drops below the pressure in both adjacent chambers in late diastole, resulting in both late diastolic MR and a second diastolic pulmonary venous forward flow.

Acidosis slows electrical conduction through the atrio-ventricular node

PubMed Central

Nisbet, Ashley M.; Burton, Francis L.; Walker, Nicola L.; Craig, Margaret A.; Cheng, Hongwei; Hancox, Jules C.; Orchard, Clive H.; Smith, Godfrey L.

2014-01-01

Acidosis affects the mechanical and electrical activity of mammalian hearts but comparatively little is known about its effects on the function of the atrio-ventricular node (AVN). In this study, the electrical activity of the epicardial surface of the left ventricle of isolated Langendorff-perfused rabbit hearts was examined using optical methods. Perfusion with hypercapnic Tyrode's solution (20% CO2, pH 6.7) increased the time of earliest activation (Tact) from 100.5 ± 7.9 to 166.1 ± 7.2 ms (n = 8) at a pacing cycle length (PCL) of 300 ms (37°C). Tact increased at shorter PCL, and the hypercapnic solution prolonged Tact further: at 150 ms PCL, Tact was prolonged from 131.0 ± 5.2 to 174.9 ± 16.3 ms. 2:1 AVN block was common at shorter cycle lengths. Atrial and ventricular conduction times were not significantly affected by the hypercapnic solution suggesting that the increased delay originated in the AVN. Isolated right atrial preparations were superfused with Tyrode's solutions at pH 7.4 (control), 6.8 and 6.3. Low pH prolonged the atrial-Hisian (AH) interval, the AVN effective and functional refractory periods and Wenckebach cycle length significantly. Complete AVN block occurred in 6 out of 9 preparations. Optical imaging of conduction at the AV junction revealed increased conduction delay in the region of the AVN, with less marked effects in atrial and ventricular tissue. Thus acidosis can dramatically prolong the AVN delay, and in combination with short cycle lengths, this can cause partial or complete AVN block and is therefore implicated in the development of brady-arrhythmias in conditions of local or systemic acidosis. PMID:25009505

Acidosis slows electrical conduction through the atrio-ventricular node.

PubMed

Nisbet, Ashley M; Burton, Francis L; Walker, Nicola L; Craig, Margaret A; Cheng, Hongwei; Hancox, Jules C; Orchard, Clive H; Smith, Godfrey L

2014-01-01

Acidosis affects the mechanical and electrical activity of mammalian hearts but comparatively little is known about its effects on the function of the atrio-ventricular node (AVN). In this study, the electrical activity of the epicardial surface of the left ventricle of isolated Langendorff-perfused rabbit hearts was examined using optical methods. Perfusion with hypercapnic Tyrode's solution (20% CO2, pH 6.7) increased the time of earliest activation (Tact) from 100.5 ± 7.9 to 166.1 ± 7.2 ms (n = 8) at a pacing cycle length (PCL) of 300 ms (37°C). Tact increased at shorter PCL, and the hypercapnic solution prolonged Tact further: at 150 ms PCL, Tact was prolonged from 131.0 ± 5.2 to 174.9 ± 16.3 ms. 2:1 AVN block was common at shorter cycle lengths. Atrial and ventricular conduction times were not significantly affected by the hypercapnic solution suggesting that the increased delay originated in the AVN. Isolated right atrial preparations were superfused with Tyrode's solutions at pH 7.4 (control), 6.8 and 6.3. Low pH prolonged the atrial-Hisian (AH) interval, the AVN effective and functional refractory periods and Wenckebach cycle length significantly. Complete AVN block occurred in 6 out of 9 preparations. Optical imaging of conduction at the AV junction revealed increased conduction delay in the region of the AVN, with less marked effects in atrial and ventricular tissue. Thus acidosis can dramatically prolong the AVN delay, and in combination with short cycle lengths, this can cause partial or complete AVN block and is therefore implicated in the development of brady-arrhythmias in conditions of local or systemic acidosis.

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.

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

PubMed

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

2003-01-01

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

Complete Atrioventricular Block Complicating Mitral Infective Endocarditis Caused by Streptococcus Agalactiae

PubMed Central

Arai, Masaru; Nagashima, Koichi; Kato, Mahoto; Akutsu, Naotaka; Hayase, Misa; Ogura, Kanako; Iwasawa, Yukino; Aizawa, Yoshihiro; Saito, Yuki; Okumura, Yasuo; Nishimaki, Haruna; Masuda, Shinobu; Hirayama, Atsushi

2016-01-01

Patient: Male, 74 Final Diagnosis: Infective endocarditis Symptoms: Apetite loss • fever Medication: — Clinical Procedure: Transesophageal echocardiography Specialty: Cardiology Objective: Rare co-existance of disease or pathology Background: Infective endocarditis (IE) involving the mitral valve can but rarely lead to complete atrioventricular block (CAVB). Case Report: A 74-year-old man with a history of infective endocarditis caused by Streptococcus gordonii (S. gordonii) presented to our emergency room with fever and loss of appetite, which had lasted for 5 days. On admission, results of serologic tests pointed to severe infection. Electrocardiography showed normal sinus rhythm with first-degree atrioventricular block and incomplete right bundle branch block, and transthoracic echocardiography and transesophageal echocardiography revealed severe mitral regurgitation caused by posterior leaflet perforation and 2 vegetations (5 mm and 6 mm) on the tricuspid valve. The patient was initially treated with ceftriaxone and gentamycin because blood and cutaneous ulcer cultures yielded S. agalactiae. On hospital day 2, however, sudden CAVB requiring transvenous pacing occurred, and the patient’s heart failure and infection worsened. Although an emergent surgery is strongly recommended, even in patients with uncontrolled heart failure or infection, surgery was not performed because of the Child-Pugh class B liver cirrhosis. Despite intensive therapy, the patient’s condition further deteriorated, and he died on hospital day 16. On postmortem examination, a 2×1-cm vegetation was seen on the perforated posterior mitral leaflet, and the infection had extended to the interventricular septum. Histologic examination revealed extensive necrosis of the AV node. Conclusions: This rare case of CAVB resulting from S. agalactiae IE points to the fact that in monitoring patients with IE involving the mitral valve, clinicians should be aware of the potential for perivalvular extension of the infection, which can lead to fatal heart block. PMID:27604147

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

PubMed

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

1982-01-01

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

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 fibrillation patients with narrow QRS who suffered from heart failure with preserved or reduced ejection fraction. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

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

PubMed

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

2012-07-01

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

Id4 functions downstream of Bmp signaling to restrict TCF function in endocardial cells during atrioventricular valve development.

PubMed

Ahuja, Suchit; Dogra, Deepika; Stainier, Didier Y R; Reischauer, Sven

2016-04-01

The atrioventricular canal (AVC) connects the atrial and ventricular chambers of the heart and its formation is critical for the development of the cardiac valves, chamber septation and formation of the cardiac conduction system. Consequently, problems in AVC formation can lead to congenital defects ranging from cardiac arrhythmia to incomplete cardiac septation. While our knowledge about early heart tube formation is relatively comprehensive, much remains to be investigated about the genes that regulate AVC formation. Here we identify a new role for the basic helix-loop-helix factor Id4 in zebrafish AVC valve development and function. id4 is first expressed in the AVC endocardium and later becomes more highly expressed in the atrial chamber. TALEN induced inactivation of id4 causes retrograde blood flow at the AV canal under heat induced stress conditions, indicating defects in AV valve function. At the molecular level, we found that id4 inactivation causes misexpression of several genes important for AVC and AV valve formation including bmp4 and spp1. We further show that id4 appears to control the number of endocardial cells that contribute to the AV valves by regulating Wnt signaling in the developing AVC endocardium. Copyright © 2016 Elsevier Inc. All rights reserved.

[Intravenous ablation of the atrio-ventricular junction in patients with supraventricular tachyarrhythmias].

PubMed

Drzewiecki, J; Trusz-Gluza, M; Wnuk-Wojnar, A; Jaklik, A; Czerwiński, C; Filipecki, A; Szydło, K; Ciemniewski, Z; Giec, L

1993-01-01

Since the first successful therapeutic DC ablation of the AV junction in 1986, we have treated 20 symptomatic patients with drug-refractory supraventricular tachyarrhythmias (average of 6 antiarrhythmic drugs prior to the ablation attempt). The primary rhythm disturbances necessitating ablation were: AV nodal reentrant tachycardia (50% of pts), atrial flutter or fibrillation, with an uncontrolled rapid ventricular response (40%), atrioventricular reentrant tachycardia using an accessory pathway (20%), atrial tachycardia (10%), and junctional reciprocating tachycardia (5%). Percutaneous catheter ablation of the AV junction was made by Gallagher's method. The USCI 4-polar catheter (7F) was used in 40% of pts, and bipolar Cordis catheter (5F) in the remaining 60%. 70% of pts received either one or two shocks, usually of 200 or 300 J during one session. Another 25% received stored cumulative energy from 800 to 1200 J (in two sessions), and one patient--1800 J (during three sessions). In 85% of pts, the immediate post-ablation conduction was third-degree AV block with the escape pacemaker, ranging from 20 to 50 beats/min., which was infra-His in 57%, and supra-His in 43% of pts. In 15% of pts were either first-degree AV block (10%) or normal AV conduction (5%). A His bundle deflection more than 0.2 mV was predictive of successful production of third-degree AV block. Except a mild and transient increase of indicating enzymes (CPK and CPK-MB) we did not observe any other serious complications directly related to the ablalation procedure. Follow-up study included 19 pts (time range from 2 to 56 months, mean 28).(ABSTRACT TRUNCATED AT 250 WORDS)

[Temporary Pacemakers - Step by Step].

PubMed

Graf, Matthias; Stiller, Patrick; Karch, Martin

2018-06-01

Symptomatic bradycardia is usually caused by abnormalities of atrioventricular conduction or sinus node dysfunction. Reversible and irreversible causes must be considered.Temporary pacemakers are used in the emergency treatment in case of severe bradyarrhythmia.They help to bridge the acute phase until spontaneous restoration of atrioventricular or sinus node function or -if spontaneous restoration fails- until a permanent pacemaker system was implanted.In the following article we discuss the commonly used temporary pacemaker systems. We demonstrate their use and correct programming by an illustrated step by step explanation. For troubleshooting a flow chart was added. © Georg Thieme Verlag KG Stuttgart · New York.

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.

Rehabilitation R&D Progress Reports 1996, Volume 34, May 1997

DTIC Science & Technology

1997-05-01

Arlington, VA 22230 PURPOSE!—Atrioventricular (AV) nodal alternans is a pathological cardiac condition characterized by a beat - to- beat alternation...regime where the AV nodal conduc- tion time alternated on a beat -to- beat basis. After using additive white noise to learn the dynamics of the underly... binaurally accord- ing to the NAL-R prescriptive formula. These groups will be followed over a period of 6 months and tested at monthly intervals. At each

Moving domain computational fluid dynamics to interface with an embryonic model of cardiac morphogenesis.

PubMed

Lee, Juhyun; Moghadam, Mahdi Esmaily; Kung, Ethan; Cao, Hung; Beebe, Tyler; Miller, Yury; Roman, Beth L; Lien, Ching-Ling; Chi, Neil C; Marsden, Alison L; Hsiai, Tzung K

2013-01-01

Peristaltic contraction of the embryonic heart tube produces time- and spatial-varying wall shear stress (WSS) and pressure gradients (∇P) across the atrioventricular (AV) canal. Zebrafish (Danio rerio) are a genetically tractable system to investigate cardiac morphogenesis. The use of Tg(fli1a:EGFP) (y1) transgenic embryos allowed for delineation and two-dimensional reconstruction of the endocardium. This time-varying wall motion was then prescribed in a two-dimensional moving domain computational fluid dynamics (CFD) model, providing new insights into spatial and temporal variations in WSS and ∇P during cardiac development. The CFD simulations were validated with particle image velocimetry (PIV) across the atrioventricular (AV) canal, revealing an increase in both velocities and heart rates, but a decrease in the duration of atrial systole from early to later stages. At 20-30 hours post fertilization (hpf), simulation results revealed bidirectional WSS across the AV canal in the heart tube in response to peristaltic motion of the wall. At 40-50 hpf, the tube structure undergoes cardiac looping, accompanied by a nearly 3-fold increase in WSS magnitude. At 110-120 hpf, distinct AV valve, atrium, ventricle, and bulbus arteriosus form, accompanied by incremental increases in both WSS magnitude and ∇P, but a decrease in bi-directional flow. Laminar flow develops across the AV canal at 20-30 hpf, and persists at 110-120 hpf. Reynolds numbers at the AV canal increase from 0.07±0.03 at 20-30 hpf to 0.23±0.07 at 110-120 hpf (p< 0.05, n=6), whereas Womersley numbers remain relatively unchanged from 0.11 to 0.13. Our moving domain simulations highlights hemodynamic changes in relation to cardiac morphogenesis; thereby, providing a 2-D quantitative approach to complement imaging analysis.

Trazodone and Omeprazole Interaction causing Frequent Second-Degree Mobitz Type 1 Atrioventricular (AV) Block (Wenckebach Phenomenon) and Syncope: A Case Report and Literature Review

PubMed Central

Akinseye, Oluwaseun A.; Alfishawy, Mostafa; Radparvar, Farshid; Bakshi, Sanjiv

2015-01-01

Patient: Male, 54 Final Diagnosis: Trazodone and omeprazole interaction causing second-degree Mobitz type 1 AV block and syncope Symptoms: Syncope Medication: — Clinical Procedure: Trazodone and omeprazole withheld Specialty: Cardiology Objective: Unexpected drug reaction Background: This case report highlights serious cardiovascular adverse effects with a conventional dose of trazodone as a result of its potential interaction with omeprazole. Case Report: A 54-year-old man who was a former smoker, with dyslipidemia, coronary artery disease, and anxiety disorder developed lightheadedness and syncope the morning of admission. He was taking trazodone 50 mg daily, omeprazole 20 mg daily, and simvastatin 20 mg at bedtime. He doubled the dose of trazodone 50 mg on the night prior to presentation to calm his anxiety. An electrocardiogram revealed sinus rhythm at 60 beats per minute and second-degree Mobitz type 1 atrioventricular (AV) block with 5:4 AV conduction. Results of basic metabolic panel, thyroid-stimulating hormone, and chest radiograph were normal. A transthoracic echocardiogram revealed aortic valve sclerosis. We tested for Lyme disease given his history of hunting in the woods 8 months prior to presentation, but the titer was negative. Trazodone and omeprazole were discontinued. By the 3rd day of medication discontinuation, all symptoms had resolved and the frequency of second-degree AV Mobitz type 1 AV block had decreased to once per hour. Conclusions: Due diligence and meticulous attention to detail needs to be exercised to uncover drug interactions as potential causes of lethal and nonlethal patient symptomatology, as in this case of syncope caused by concomitant use of trazodone and a widely prescribed medication, omeprazole. PMID:26017199

Determination of the optimal atrioventricular interval in sick sinus syndrome during DDD pacing.

PubMed

Kato, Masaya; Dote, Keigo; Sasaki, Shota; Goto, Kenji; Takemoto, Hiroaki; Habara, Seiji; Hasegawa, Daiji; Matsuda, Osamu

2005-09-01

Although the AAI pacing mode has been shown to be electromechanically superior to the DDD pacing mode in sick sinus syndrome (SSS), there is evidence suggesting that during AAI pacing the presence of natural ventricular activation pattern is not enough for hemodynamic benefit to occur. Myocardial performance index (MPI) is a simply measurable Doppler-derived index of combined systolic and diastolic myocardial performance. The aim of this study was to investigate whether AAI pacing mode is electromechanically superior to the DDD mode in patients with SSS by using Doppler-derived MPI. Thirty-nine SSS patients with dual-chamber pacing devices were evaluated by using Doppler echocardiography in AAI mode and DDD mode. The optimal atrioventricular (AV) interval in DDD mode was determined and atrial stimulus-R interval was measured in AAI mode. The ratio of the atrial stimulus-R interval to the optimal AV interval was defined as relative AV interval (rAVI) and the ratio of MPI in AAI mode to that in DDD mode was defined as relative MPI (rMPI). The rMPI was significantly correlated with atrial stimulus-R interval and rAVI (r = 0.57, P = 0.0002, and r = 0.67, P < 0.0001, respectively). A cutoff point of 1.73 for rAVI provided optimum sensitivity and specificity for rMPI >1 based on the receiver operator curves. Even though the intrinsic AV conduction is moderately prolonged, some SSS patients with dual-chamber pacing devices benefit from the ventricular pacing with optimal AV interval. MPI is useful to determine the optimal pacing mode in acute experiment.

Renal sympathetic denervation improves rate control in patients with symptomatic persistent atrial fibrillation and hypertension.

PubMed

Qiu, Min; Shan, Qijun; Chen, Chun; Geng, Jie; Guo, Jiqun; Zhou, Xiujuan; Qian, Weichong; Tang, Lijun; Yin, Yuehui

2016-02-01

The aim of this study was to investigate whether renal sympathetic denervation (RSD) improves ventricular heart rate (HR) control in patients with persistent atrial fibrillation (AF). Twenty-one patients (aged 57.5 ± 10.2 years, 76.2% male) with persistent AF and hypertension underwent RSD and completed 7-days follow-up evaluations, including 24-hour Holter monitoring (Holter), blood pressure (BP), 24-hour ambulatory BP monitoring (ABPM). Patients were grouped into tertiles of average HR at baseline Holter recording for evaluation of RSD effects on atrioventricular (AV) node (group 1: HR ≧ 90 bpm; group 2: 80 bpm ≦ HR < 90 bpm; group 3: HR < 80 bpm). All patients successfully underwent RSD without any complications. The clinical and procedural characteristics were similar in all groups of patients. No significant changes in BP were observed in the three groups before and after RSD. Compared with baseline, the average HR (Holter) of patients in group 1, 2 and 3 had a reduction of 22.6 ± 13.2 bpm (83.3 ± 4.9 vs 106.0 ± 14.6, P = 0.004), 9.7 ± 7.8 bpm (75.7 ± 7.6 vs 85.4 ± 3.7, P = 0.017) and 2.3 ± 2.9 bpm (71.4 ± 4.0 vs 73.7 ± 4.7, P = 0.089) at 7 days after RSD, respectively. RSD could improve ventricular HR control in patients with persistent AF. RSD slowed AV node conduction in baseline HR-dependent manner. RSD may become an alternative non-pharmaceutical tool for rate control in patients with persistent AF.

Management and outcome of topical beta-blockerinduced atrioventricular block

PubMed Central

Özcan, Kazım Serhan; Güngör, Barış; Tekkeşin, Ahmet İlker; Altay, Servet; Ekmekçi, Ahmet; Toprak, Ercan; Yıldırım, Ersin; Çalık, Nazmi; Alper, Ahmet Taha; Gürkan, Kadir; Erdinler, İzzet; Osmonov, Damirbek

2015-01-01

Summary Background Topical beta-blockers have a well-established role in the treatment of glaucoma. We aimed to investigate the outcome of patients who developed symptomatic atrioventricular (AV) block induced by topical beta-blockers. Methods All patients admitted or discharged from our institution, the Siyami Ersek Training and Research Hospital, between January 2009 and January 2013 with a diagnosis of AV block were included in the study. Subjects using ophthalmic beta-blockers were recruited and followed for permanent pacemaker requirement during hospitalisation and for three months after discontinuation of the drug. A permanent pacemaker was implanted in patients in whom AV block persisted beyond 72 hours or recurred during the follow-up period. Results A total of 1 122 patients were hospitalised with a diagnosis of AV block and a permanent pacemaker was implanted in 946 cases (84.3%) during the study period. Thirteen patients using ophthalmic beta-blockers for the treatment of glaucoma and no other rate-limiting drugs were included in the study. On electrocardiography, eight patients had complete AV block and five had high-degree AV block. The ophthalmic beta-blockers used were timolol in seven patients (55%), betaxolol in four (30%), and cartelol in two cases (15%). The mean duration of ophthalmic beta-blocker treatment was 30.1 ± 15.9 months. After drug discontinuation, in 10 patients the block persisted and a permanent pacemaker was implanted. During follow up, one more patient required pacemaker implantation. Therefore in total, pacemakers were implanted in 11 out of 13 patients (84.6%). The pacemaker implantation rate did not differ according to the type of topical beta-blocker used (p = 0.37). The presence of infra-nodal block on electrocardiography was associated with higher rates of pacemaker implantation. Conclusion Our results indicate that topical beta-blockers for the treatment of glaucoma may cause severe conduction abnormalities and when AV block occurs, pacemaker implantation is required in a high percentage of the patients. PMID:26659434

Influence of the heart rate and atrioventricular delays on vortex evolution and blood transport inside the left ventricle

NASA Astrophysics Data System (ADS)

Hendabadi, Sahar; Martinez-Legazpi, Pablo; Benito, Yolanda; Bermejo, Javier; Del Alamo, Juan Carlos; Shadden, Shawn

2013-11-01

Cardiac resynchronization therapy (CRT) is used to help restore coordinated pumping of the ventricles by overcoming delays in electrical conduction due to cardiac disease. This is accomplished by a specialized cardiac pacemaker that is able to adjust the atrioventricular (AV) delay.A major clinical challenge is to adjust the pacing strategy to best coordinate the blood flow mechanics of ventricular filling and ejection. To this end, we have studied the difference in the vortex formation and its evolution inside the left ventricle (LV) for 4 different AV delays in a cohort of patients with implanted pacemakers. A reconstruction algorithm was used to obtain 2D velocity over the apical long-axis view of the LV from color Doppler and B-mode ultrasound data. To study blood transport, we have identified Lagrangian coherent structures to determine moving boundaries of the blood volumes injected to the LV in diastole and ejected to the aorta in systole. In all cases, we have analyzed the differences in filling and ejection patterns and the blood transport during the E-wave and A-wave formation.Finally we have assessed the influence of the AV delay on 2 indices of stasis, direct flow and residence time.The findings shed insight to the optimization of AV delays in patients undergoing CRT. NIH award 5R21HL108268 and grants PIS09/02603 and RD06/0010 from the Plan Nacional de Investigacion Cientifica, Spain.

Expression of key ion channels in the rat cardiac conduction system by laser capture microdissection and quantitative real-time PCR.

PubMed

Ou, Yan; Niu, Xiao-lin; Ren, Fu-xian

2010-09-01

The objective of this study was to investigate the molecular basis of the inferior nodal extension (INE) in the atrioventricular junctional area that accounts for arrhythmias. The INE was separated from the adult rat heart by laser capture microdissection. The mRNA expression of ion channels was detected by quantitative real-time PCR. Hierarchical clustering was used to demonstrate clustering of expression of genes in sections. The mRNA expression of HCN4, Ca(v)3.1 and Ca(v)3.2 was high in the INE, atrioventricular node and sino-atrial node, and that of Ca(v)3.2 high in Purkinje fibres. Although the expression of HCN1 and Ca(v)1.3 was low in the rat heart, it was relatively higher in the INE, atrioventricular node and sino-atrial node than in right atrial and right ventricular (working) myocytes. Both HCN2 and Ca(v)1.2 were expressed at higher levels in working myocytes than in nodal tissues and in the INE. Hierarchical clustering analysis demonstrated that the expression of the HCN and calcium channels in INE was similar to that in the slow-response automatic cells and different from that in working myocytes and Purkinje fibres. The expression of HCN and calcium channels in the INE of the adult rat heart is similar to that of slow-response automatic cells and provides a substrate for automatic phase 4 depolarization in cells.

Constitutional rho-kinase regulates atrioventricular nodal conduction and ventricular repolarization of the canine heart.

PubMed

Sugiyama, Atsushi; Takahara, Akira; Yatomi, Yutaka; Satoh, Yoshioki; Nakamura, Yuji; Hashimoto, Keitaro

2003-06-01

Given the limited information, physiological roles of Rho-kinase in the cardiac conduction system and ventricular repolarization process were assessed in comparison with those in the coronary vascular tone. A specific Rho-kinase inhibitor Y-27632 was administered to the nutrient coronary artery of the canine isolated, blood-perfused atrioventricular node preparation under the monitoring of the ventricular monophasic action potentials. Administration of Y-27632 moderately suppressed the atrioventricular nodal conduction, slightly but significantly accelerated the repolarization process, and potently increased the coronary blood flow, whereas it hardly affected the intraventricular conduction. The estimated concentrations of Y-27632 causing the currently observed effects were enough to inhibit Rho-kinase. These results suggest that constitutional Rho-kinase functions to moderately facilitate the atrioventricular nodal conduction, slightly delay ventricular repolarization process, and significantly increase the coronary vascular tone.

Valvular dysplasia and congestive heart failure in a juvenile African penguin (Spheniscus demersus).

PubMed

McNaughton, Allyson; Frasca, Salvatore; Mishra, Neha; Tuttle, Allison D

2014-12-01

Abstract: An aquarium-housed, 6-mo-old African penguin (Spheniscus demersus) presented with acute respiratory distress. Auscultation revealed a grade II-III systolic murmur in the absence of adventitial sounds, and an enlarged heart without pulmonary edema was seen radiographically. Echocardiographic evaluation revealed atrioventricular (AV) valvular dysplasia and ventricular enlargement. The penguin was treated with enalapril, furosemide, and pimobendan but died within 3 wk of detection of the murmur. Congenital dysplasia of the right AV valve with right atrial and ventricular dilation and ventricular hypertrophy were diagnosed on postmortem examination.

Transvenous permanent pacemaker implantation in dextrocardia: technique, challenges, outcome, and a brief review of literature.

PubMed

Shenthar, Jayaprakash; Rai, Maneesh K; Walia, Rohit; Ghanta, Somasekhar; Sreekumar, Praveen; Reddy, Satish S

2014-09-01

Dextrocardia is a rare congenital anomaly. Pacemaker implantation in dextrocardia can be challenging because of the distorted anatomy and associated anomalies. The literature regarding implantation of pacemaker in dextrocardia is scarce. The study involved retrospective analysis of records of patients with dextrocardia who had undergone pacemaker implantation between January 2006 and July 2013 from a single centre. Six patients with dextrocardia (five males and one female) underwent permanent pacemaker implantation (PPI) between January 2006 and July 2013. Of them, three had situs solitus dextrocardia and three situs inversus dextrocardia. All three patients with situs solitus dextrocardia had associated corrected transposition of great arteries. The indication for pacemaker implantation was symptomatic complete atrioventricular (AV) block in four, high-grade AV block in one, and sinus node dysfunction in one patient. A favourable outcome was noted during a mean follow-up of 3.9 years (4 months to 7 years) with one patient needing a pulse generator replacement. Permanent pacemaker implantation in dextrocardia can be challenging because of the distorted anatomy. Use of a technique employing angiography to delineate chamber anatomy and relationship can assist the operator during such difficult PPIs. The medium- and long-term survival after a successful pacemaker implantation in dextrocardia is favourable. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Lesion size estimator of cardiac radiofrequency ablation at different common locations with different tip temperatures.

PubMed

Lai, Yu-Chi; Choy, Young Bin; Haemmerich, Dieter; Vorperian, Vicken R; Webster, John G

2004-10-01

Finite element method (FEM) analysis has become a common method to analyze the lesion formation during temperature-controlled radiofrequency (RF) cardiac ablation. We present a process of FEM modeling a system including blood, myocardium, and an ablation catheter with a thermistor embedded at the tip. The simulation used a simple proportional-integral (PI) controller to control the entire process operated in temperature-controlled mode. Several factors affect the lesion size such as target temperature, blood flow rate, and application time. We simulated the time response of RF ablation at different locations by using different target temperatures. The applied sites were divided into two groups each with a different convective heat transfer coefficient. The first group was high-flow such as the atrioventricular (AV) node and the atrial aspect of the AV annulus, and the other was low-flow such as beneath the valve or inside the coronary sinus. Results showed the change of lesion depth and lesion width with time, under different conditions. We collected data for all conditions and used it to create a database. We implemented a user-interface, the lesion size estimator, where the user enters set temperature and location. Based on the database, the software estimated lesion dimensions during different applied durations. This software could be used as a first-step predictor to help the electrophysiologist choose treatment parameters.

Moving Domain Computational Fluid Dynamics to Interface with an Embryonic Model of Cardiac Morphogenesis

PubMed Central

Lee, Juhyun; Moghadam, Mahdi Esmaily; Kung, Ethan; Cao, Hung; Beebe, Tyler; Miller, Yury; Roman, Beth L.; Lien, Ching-Ling; Chi, Neil C.; Marsden, Alison L.; Hsiai, Tzung K.

2013-01-01

Peristaltic contraction of the embryonic heart tube produces time- and spatial-varying wall shear stress (WSS) and pressure gradients (∇P) across the atrioventricular (AV) canal. Zebrafish (Danio rerio) are a genetically tractable system to investigate cardiac morphogenesis. The use of Tg(fli1a:EGFP)y1 transgenic embryos allowed for delineation and two-dimensional reconstruction of the endocardium. This time-varying wall motion was then prescribed in a two-dimensional moving domain computational fluid dynamics (CFD) model, providing new insights into spatial and temporal variations in WSS and ∇P during cardiac development. The CFD simulations were validated with particle image velocimetry (PIV) across the atrioventricular (AV) canal, revealing an increase in both velocities and heart rates, but a decrease in the duration of atrial systole from early to later stages. At 20-30 hours post fertilization (hpf), simulation results revealed bidirectional WSS across the AV canal in the heart tube in response to peristaltic motion of the wall. At 40-50 hpf, the tube structure undergoes cardiac looping, accompanied by a nearly 3-fold increase in WSS magnitude. At 110-120 hpf, distinct AV valve, atrium, ventricle, and bulbus arteriosus form, accompanied by incremental increases in both WSS magnitude and ∇P, but a decrease in bi-directional flow. Laminar flow develops across the AV canal at 20-30 hpf, and persists at 110-120 hpf. Reynolds numbers at the AV canal increase from 0.07±0.03 at 20-30 hpf to 0.23±0.07 at 110-120 hpf (p< 0.05, n=6), whereas Womersley numbers remain relatively unchanged from 0.11 to 0.13. Our moving domain simulations highlights hemodynamic changes in relation to cardiac morphogenesis; thereby, providing a 2-D quantitative approach to complement imaging analysis. PMID:24009714

Modeling the influence of the VV delay for CRT on the electrical activation patterns in absence of conduction through the AV node

NASA Astrophysics Data System (ADS)

Romero, D. A.; Sebastián, Rafael; Plank, Gernot; Vigmond, Edward J.; Frangi, Alejandro F.

2008-03-01

From epidemiological studies, it has been shown that 0.2% of men and 0.1% of women suffer from a degree of atrioventricular (AV) block. In recent years, the palliative treatment for third degree AV block has included Cardiac Resynchronization Therapy (CRT). It was found that patients show more clinical improvement in the long term with CRT compared with single chamber devices. Still, an important group of patients does not improve their hemodynamic function as much as could be expected. A better understanding of the basis for optimizing the devices settings (among which the VV delay) will help to increase the number of responders. In this work, a finite element model of the left and right ventricles was generated using an atlas-based approach for their segmentation, which includes fiber orientation. The electrical activity was simulated with the electrophysiological solver CARP, using the Ten Tusscher et al. ionic model for the myocardium, and the DiFrancesco-Noble for Purkinje fibers. The model is representative of a patient without dilated or ischemic cardiomyopathy. The simulation results were analyzed for total activation times and latest activated regions at different VV delays and pre-activations (RV pre-activated, LV pre-activated). To optimize the solution, simulations are compared against the His-Purkinje network activation (normal physiological conduction), and interventricular septum activation (as collision point for the two wave fronts). The results were analyzed using Pearson's coefficient of correlation for point to point comparisons between simulation cases. The results of this study contribute to gain insight on the VV delay and how its adjustment might influence response to CRT and how it can be used to optimize the treatment.

A comparison of the chronotropic and dromotropic actions between adenosine triphosphate and edrophonium in patients undergoing coronary artery bypass graft surgery.

PubMed

Watanabe, Seiji; Kono, Yasuo; Oishi-Tobinaga, Yoko; Yamada, Shin-ichi; Hara, Masato; Kano, Tatsuhiko

2002-10-01

To compare the effects of the stimulation of adenosine receptors and acetylcholine receptors in the cardiac conduction system in patients with ischemic heart disease. Prospective. University hospital. Patients scheduled for coronary artery bypass graft surgery (n = 37). The patients were divided into 3 groups: control group (n = 9), adenosine triphosphate (ATP) group (n = 12), and edrophonium group (n = 16). ATP (10 mg) or edrophonium (0.25 mg/kg) followed by saline or the same amount of saline was injected through a central venous catheter. ATP induced atrioventricular block in 10 of 12 patients (83%). The ATP injection produced a more prominent prolongation in the PQ duration (P-R interval) (139%) than in the P-P interval (105%) at the last beat before the development of atrioventricular block. The prolongation in the P-P interval (11%, average 85 msec) and PQ duration during atrioventricular block disappeared immediately after the restoration of atrioventricular conduction. After edrophonium, the maximal prolongation in P-P (118%, p < 0.01) and PQ (120%, p < 0.01) intervals was the same. P-P interval remained prolonged (p < 0.01) after PQ interval returned to baseline. Neither ATP nor edrophonium affected the QRS duration. These findings suggest that ATP predominantly inhibited atrioventricular conduction rather than the firing rate of sinoatrial nodes, and edrophonium inhibited both proportionally even with prolonged inhibitory action on the sinoatrial nodes. An injection of ATP is needed only when a transient cardiac standstill is requested, such as in endovascular grafting surgery. Edrophonium may be used to slow heart rate during coronary artery bypass graft surgery. Copyright 2002, Elsevier Science (USA). All rights reserved.

Inverse Relationship Between Membranous Septal Length and the Risk of Atrioventricular Block in Patients Undergoing Transcatheter Aortic Valve Implantation.

PubMed

Hamdan, Ashraf; Guetta, Victor; Klempfner, Robert; Konen, Eli; Raanani, Ehud; Glikson, Michael; Goitein, Orly; Segev, Amit; Barbash, Israel; Fefer, Paul; Spiegelstein, Dan; Goldenberg, Ilan; Schwammenthal, Ehud

2015-08-17

This study sought to examine whether imaging of the atrioventricular (AV) membranous septum (MS) by computed tomography (CT) can be used to identify patient-specific anatomic risk of high-degree AV block and permanent pacemaker (PPM) implantation before transcatheter aortic valve implantation (TAVI) with self-expandable valves. MS length represents an anatomic surrogate of the distance between the aortic annulus and the bundle of His and may therefore be inversely related to the risk of conduction system abnormalities after TAVI. Seventy-three consecutive patients with severe aortic stenosis underwent contrast-enhanced CT before TAVI. The aortic annulus, aortic valve, and AV junction were assessed, and MS length was measured in the coronal view. In 13 patients (18%), high-degree AV block developed, and 21 patients (29%) received a PPM. Multivariable logistic regression analysis revealed MS length as the most powerful pre-procedural independent predictor of high-degree AV block (odds ratio [OR]: 1.35, 95% confidence interval [CI]: 1.1 to 1.7, p = 0.01) and PPM implantation (OR: 1.43, 95% CI: 1.1 to 1.8, p = 0.002). When taking into account pre- and post-procedural parameters, the difference between MS length and implantation depth emerged as the most powerful independent predictor of high-degree AV block (OR: 1.4, 95% CI: 1.2 to 1.7, p < 0.001), whereas the difference between MS length and implantation depth and calcification in the basal septum were the most powerful independent predictors of PPM implantation (OR: 1.39, 95% CI: 1.2 to 1.7, p < 0.001 and OR: 4.9, 95% CI: 1.2 to 20.5, p = 0.03; respectively). Short MS, insufficient difference between MS length and implantation depth, and the presence of calcification in the basal septum, factors that may all facilitate mechanical compression of the conduction tissue by the implanted valve, predict conduction abnormalities after TAVI with self-expandable valves. CT assessment of membranous septal anatomy provides unique pre-procedural information about the patient-specific propensity for the risk of AV block. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Complete A-V block: incidental or a part of cor triatriatum dexter.

PubMed

Guler, Y; Akgun, T; Toprak, C; Guler, A; Esen, A M

2014-05-01

Cor triatriatum dexter (CTD) is an extremely rare cardiac anomaly in which the right atrium is divided into two distinct chambers by a membrane. The persistence of the right valve of sinus venosus results in a complete septation of the right atrium. This anomaly is frequently associated with other right-sided cardiac abnormalities. Its clinical manifestation and the need for intervention are determined by the number and the size of the fenestrations on the membrane, associated cardiac anomalies and arrhythmias. We describe a case of CTD in a patient with complete atrioventricular (A-V) block.

Cardiac Resynchronization Therapy and phase resetting of the sinoatrial node: A conjecture

NASA Astrophysics Data System (ADS)

Cantini, Federico; Varanini, Maurizio; Macerata, Alberto; Piacenti, Marcello; Morales, Maria-Aurora; Balocchi, Rita

2007-03-01

Congestive heart failure is a severe chronic disease often associated with disorders that alter the mechanisms of excitation-contraction coupling that may result in an asynchronous left ventricular motion which may further impair the ability of the failing heart to eject blood. In recent years a therapeutic approach to resynchronize the ventricles (cardiac resynchronization therapy, CRT) has been performed through the use of a pacemaker device able to provide atrial-based biventricular stimulation. Atrial lead senses the spontaneous occurrence of cells depolarization and sends the information to the generator which, in turn, after a settled delay [atrioventricular (AV) delay], sends electrical impulses to both ventricles to stimulate their synchronous contraction. Recent studies performed on heart rate behavior of chronically implanted patients at different epochs after implantation have shown that CRT can lead to sustained overall improvement of heart function with a reduction in morbidity and mortality. At this moment, however, there are no studies about CRT effects on spontaneous heart activity of chronically implanted patients. We performed an experimental study in which the electrocardiographic signal of five subjects under chronic CRT was recorded during the activity of the pacemaker programmed at different AV delays and under spontaneous cardiac activity after pacemaker deactivation. The different behavior of heart rate variability during pacemaker activity and after pacemaker deactivation suggested the hypothesis of a phase resetting mechanism induced by the pacemaker stimulus on the sinoatrial (SA) node, a phenomenon already known in literature for aggregate of cardiac cells, but still unexplored in vivo. The constraints imposed by the nature of our study (in vivo tests) made it impossible to plan an experiment to prove our hypothesis directly. We therefore considered the best attainable result would be to prove the accordance of our data to the conjecture through the use of models and physical considerations. We first used the data of literature on far-field effects of cardiac defibrillators to prove that the pacemaker impulses delivered to the two ventricles were able to induce modifications in membrane voltage at the level of the SA node. To simulate a phase resetting mechanism of the SA node, we used a Van der Pol modified model to allow the possibility of changing the refractory period and the firing frequency of the cells separately. With appropriate parameters of the model we reproduced phase response curves that can account for our experimental data. Furthermore, the simulated curves closely resemble the functional form proposed in literature for perturbed aggregate of cardiac cells. Despite the small sample of subjects investigated and the limited number of ECG recordings at different AV delays, we think we have proved the plausibility of the proposed conjecture.

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

PubMed

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

2018-06-01

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

Heart Block

MedlinePlus

... to begin a new heartbeat 60 to 100 times a minute. From the SA node, the signal travels through the right and left atria. This causes ... AV node. This slowing allows the ventricles enough time to finish filling with ... leaves the AV node and travels along a pathway called the bundle of His. ...

Long-Term Effects of Atrial Ganglionated Plexi Ablation on Function and Structure of Sinoatrial and Atrioventricular Node in Canine.

PubMed

Zhang, Ming; Wang, Ximin; Xie, Xinxing; Wang, Zhongsu; Liu, Xiaoyan; Guan, Juan; Wang, Weizong; Li, Zhan; Wang, Jiangrong; Gao, Mei; Hou, Yinglong

2015-10-01

Long-term effects of ganglionated plexi (GP) ablation on sinoatrial node (SAN) and atrioventricular node (AVN) remain unclear. This study is to investigate the long-term effects of ablation of cardiac anterior right GP (ARGP) and inferior right GP (IRGP) on function and structure of SAN and AVN in canine. Thirty-two dogs were randomly divided into an operated group (n = 24) and sham-operated group (n = 8). ARGP and IRGP were ablated in operated group which was randomly divided into three subgroups according to the period of evaluation after operation (1 month, 6 months, 12 months). The functional and histological characteristics of SAN and AVN, as well as the expression of connexin (Cx) 43 and Cx 45 in SAN and AVN, were evaluated before and after ablation. Resting heart rate was increased and AVN effective refractory period was prolonged and sinus node recovery time (SNRT) and corrected SNRT were shortened immediately after ablation. These changes were reverted to preablation level after 1 month. At 1 month, ventricular rate during atrial fibrillation was slowed, atria-His intervals were prolonged, and Cx43 and Cx45 expression in SAN and AVN were downregulated. At 6 months, all changes were reverted to preablation level. The histological characteristics of SAN and AVN did not change. Ablation of ARGP and IRGP has short-term effects on function and structure of SAN and AVN rather than long-term effects, which suggests that ablation of ARGP and IRGP is safe. Atrioventricular conduction dysfunction after ablation may be related to downregulated Cx43 and Cx45 expression in AVN. © 2015 Wiley Periodicals, Inc.

Directly ventricular septal defect closure without using arteriovenous wire loop: Our adult case series using transarterial retrograde approach

PubMed Central

Pekel, Nihat; Ercan, Ertuğrul; Özpelit, Mehmet Emre; Özyurtlu, Ferhat; Yılmaz, Akar; Topaloğlu, Caner; Saygı, Serkan; Yakan, Serkan; Tengiz, İstemihan

2017-01-01

Objective: The standard transcatheter ventricular septal defects (VSD) closure procedure is established with arteriovenous (AV) loop and is called as antegrade approach. The directly retrograde transarterial VSD closure without using AV loop might be better option as shortens the procedure time and decreases radiation exposure. Methods: Our series consist of twelve sequential adult cases with congenital VSDs (seven with perimembranous, four with muscular, one with postoperative residuel VSD). The mean age was 26.9 (Range 18–58), the mean height was 168.75 cm (Range 155–185cm), and the mean body mass index was 23.4 (Range 17.3–28.4). Maximum and minimum defect sizes were 10 and 5 mm and the mean defect size was 6.24 mm. The procedure was performed with left heart catheterization and advancing the delivery sheath over the stiff exchange wire then VSD occlusion from left side. Results: The defects were successfully closed with this technique in eleven patients. In sixth patient, the defect could not be cannulated by the delivery sheath, as the tip of the sheath did not reach the defect and VSD was closed with same sheath by standard transvenous approach using AV loop. We didn’t encounter any complication releated to semilunar or atrioventricular valves. Atrioventricular conduction system was not affected by the procedure in any patients. The median procedure and fluoroscopy times were 66 and 16.5 minutes respectively. Conclusion: Transarterial retrograde VSD closure without using AV loop simplifies the procedure, decreases the radiation exposure, and shortens the procedure time. The only limitation in adult patients is delivery sheath length. PMID:28315566

A case of advanced second-degree atrioventricular block in a ferret secondary to lymphoma

PubMed Central

Menicagli, F.; Lanza, A.; Sbrocca, F.; Baldi, A.; Spugnini, E.P.

2016-01-01

A female ferret was referred as an emergency for severe respiratory distress symptoms. At presentation, the patient was listlessness, dyspnoeic, and hyper-responsive. The clinical examination evidenced dyspnea with cyanosis, altered cardiac rhythm, and hepatomegaly. Electrocardiography showed an advanced second-degree atrioventricular (AV) block. The liver aspirate was diagnostic for lymphoma. The patient did not respond to supportive therapy and rapidly died. Post-mortem exams confirmed the presence of lymphoma with hepatic involvement. Moreover, a pericardial lymphocytic infiltration and a widespread myocardial nodular localization of lymphoma were evidenced as well. This condition was probably the cause of the cardiac arrhythmia. To the best of our knowledge, ours is the first report of cardiac lymphoma causing heart block in ferrets. PMID:27200273

No patch technique for complete atrioventricular canal repair.

PubMed

Aramendi, José Ignacio; Rodriguez, Miguel Angel; Luis, Teresa; Voces, Roberto

2006-08-01

We describe our initial experience with a new technique, consisting in direct closure of the ventricular septal defect component of the AV canal, by directly attaching the common bridging leaflets to the crest of the ventricular septum with interrupted sutures. After closure of the cleft, the ostium primum defect was closed with a running suture suturing the border of the septum primum to the newly created AV valve annulus. Three patients were operated upon. There was no mortality. Mean ischemic time was 39 min and mean pump time 77 min. All patients remained in sinus rhythm. At follow-up only trivial or mild mitral regurgitation was observed. This new technique permits the repair of complete AV canal without the need for any patch. It is fast, simple and reproducible.

A novel predictive pharmacokinetic/pharmacodynamic model of repolarization prolongation derived from the effects of terfenadine, cisapride and E-4031 in the conscious chronic av node--ablated, His bundle-paced dog.

PubMed

Nolan, Emily R; Feng, Meihua Rose; Koup, Jeffrey R; Liu, Jing; Turluck, Daniel; Zhang, Yiqun; Paulissen, Jerome B; Olivier, N Bari; Miller, Teresa; Bailie, Marc B

2006-01-01

Terfenadine, cisapride, and E-4031, three drugs that prolong ventricular repolarization, were selected to evaluate the sensitivity of the conscious chronic atrioventricular node--ablated, His bundle-paced Dog for defining drug induced cardiac repolarization prolongation. A novel predictive pharmacokinetic/pharmacodynamic model of repolarization prolongation was generated from these data. Three male beagle dogs underwent radiofrequency AV nodal ablation, and placement of a His bundle-pacing lead and programmable pacemaker under anesthesia. Each dog was restrained in a sling for a series of increasing dose infusions of each drug while maintained at a constant heart rate of 80 beats/min. RT interval, a surrogate for QT interval in His bundle-paced dogs, was recorded throughout the experiment. E-4031 induced a statistically significant RT prolongation at the highest three doses. Cisapride resulted in a dose-dependent increase in RT interval, which was statistically significant at the two highest doses. Terfenadine induced a dose-dependent RT interval prolongation with a statistically significant change occurring only at the highest dose. The relationship between drug concentration and RT interval change was described by a sigmoid E(max) model with an effect site. Maximum RT change (E(max)), free drug concentration at half of the maximum effect (EC(50)), and free drug concentration associated with a 10 ms RT prolongation (EC(10 ms)) were estimated. A linear correlation between EC(10 ms) and HERG IC(50) values was identified. The conscious dog with His bundle-pacing detects delayed cardiac repolarization related to I(Kr) inhibition, and detects repolarization change induced by drugs with activity at multiple ion channels. A clinically relevant sensitivity and a linear correlation with in vitro HERG data make the conscious His bundle-paced dog a valuable tool for detecting repolarization effect of new chemical entities.

Epicardially-derived Fibroblasts Preferentially Contribute to the Parietal Leaflets of the Atrioventricular Valves in the Murine Heart

PubMed Central

Wessels, Andy; van den Hoff, Maurice J. B.; Adamo, Richard F.; Phelps, Aimee L.; Lockhart, Marie M.; Sauls, Kimberly; Briggs, Laura E.; Norris, Russell A.; van Wijk, Bram; Perez-Pomares, Jose M.; Dettman, Robert W.; Burch, John B. E.

2012-01-01

The importance of the epicardium for myocardial and valvuloseptal development has been well established; perturbation of epicardial development results in cardiac abnormalities, including thinning of the ventricular myocardial wall and malformations of the atrioventricular valvuloseptal complex. To determine the spatiotemporal contribution of epicardially derived cells to the developing fibroblast population in the heart we have used a mWt1/IRES/GFP-Cre mouse to trace the fate of EPDCs from embryonic day (ED)10 until birth. EPDCs begin to populate the compact ventricular myocardium around ED12. The migration of epicardially-derived fibroblasts toward the interface between compact and trabecular myocardium is completed around ED14. Remarkably, epicardially-derived fibroblasts do not migrate into the trabecular myocardium until after ED17. Migration of EPDCs into the atrioventricular cushion mesenchyme commences around ED12. As development progresses, the number of EPDCs increases significantly, specifically in the leaflets which derive from the lateral atrioventricular cushions. In these developing leaflets the epicardially-derived fibroblasts eventually largely replace the endocardially-derived cells. Importantly, the contribution of EPDCs to the leaflets derived from the major AV cushions is very limited. The differential contribution of EPDCs to the various leaflets of the atrioventricular valves provides a new paradigm in valve development and could lead to new insights into the pathogenesis of abnormalities that preferentially affect individual components of this region of the heart. The notion that there is a significant difference in the contribution of epicardially and endocardially derived cells to the individual leaflets of the atrioventricular valves has also important pragmatic consequences for the use of endocardial and epicardial cre-mouse models in studies of heart development. PMID:22546693

[Sudden cardiac death due to sarcoidosis. Case report].

PubMed

Sejben, István; Som, Zoltán; Cserni, Gábor

2017-07-01

Sarcoidosis is a systemic granulomatous disease of unknown aetiology, which is characterized by bilateral hilar lymphadenopathy and pulmonary disease. Clinically detected cardiac involvement occurs in 5% of sarcoid patients, although cardiac manifestations are discovered in 25% of the cases at autopsy. Sarcoid heart disease frequently causes atrioventricular block. The authors present the case of a 44-year-old man with bradycardia. On admission, second degree Mobitz II, then third degree atrioventricular block was diagnosed. Coronarography showed normal coronary arteries. 2.5 years following artificial Biotronik Entovis DR type pacemaker implantation, sudden cardiac death occurred. Autopsy revealed sarcoidosis with cardiac, pulmonary, splenic, renal and lymph node involvement. In case of young or middle-aged patients with atrioventricular block, it is best to search for other causes if the most common coronary origin can be excluded. Orv Hetil. 2017; 158(27): 1067-1070.

[A case of severe bradycardia and AV block during administration of propofol].

PubMed

Takase, Hajime; Kudoh, Akira; Takazawa, Tomoko

2003-09-01

A 69-yr-old man underwent emergency laparotomy. He was in endotoxic shock. Preoperative evaluation including a full blood count, chest X-ray and ECG were normal. Body temperature was 37.4 degrees C. Preoperative arterial pressure was 140/80 mmHg and heart rate 65 bpm. Anesthesia was induced with ketamine 100 mg, propofol 20 mg, fentanyl 50 micrograms and vecuronium 4 mg and maintained with propofol 4 mg.kg-1.hr-1 and fentanyl. Soon after opening the abdominal peritoneum, severe bradycardia (< 20 bpm) occurred, but it was effectively treated by ephedrine 16 mg. After that, surgery was performed uneventfully. In the intensive care unit (ICU), the patient developed four episodes of severe atrioventricular (AV) block after stimulation of the trachea by suction drainage under sedation with propofol, although there was no AV block during sedation with ketamine and propofol. After stopping propofol, the AV block was no longer observed. He was discharged from the ICU on the 12th postoperative day. Postoperative Holter ECG and echocardiography showed no abnormalities. It is likely that stimulation of the trachea triggered vagovagal reflex and propofol prolonged AV conduction, causing the AV block.

Different mechanisms for diastolic mitral regurgitation illustrated by three comparative cases.

PubMed

Sisu, Roxana C; Vinereanu, Dragos

2011-04-01

Diastolic mitral regurgitation (DMR) has been reported in patients with AV block, aortic regurgitation, cardiomyopathies, and in patients with long filling periods in atrial tachyarrhythmias. The mechanism for DMR is a reversal in the atrioventricular gradient during diastole. However, because of its relatively low velocity, it may be difficult to diagnose noninvasively. We present three different cases of diastolic MR in 2:1 second-degree AV block, atrial flutter, and dilated cardiomyopathy, with different locations in diastole. Diastolic tricuspid regurgitation commonly accompanies DMR. Careful analysis of echocardiographical images related with online ECG is very important in order to delineate systolic and DMR, and their timing in systole and diastole. © 2011, Wiley Periodicals, Inc.

Clinical feasibility of exercise-based A-V interval optimization for cardiac resynchronization: a pilot study.

PubMed

Choudhuri, Indrajit; MacCarter, Dean; Shaw, Rachael; Anderson, Steve; St Cyr, John; Niazi, Imran

2014-11-01

One-third of eligible patients fail to respond to cardiac resynchronization therapy (CRT). Current methods to "optimize" the atrio-ventricular (A-V) interval are performed at rest, which may limit its efficacy during daily activities. We hypothesized that low-intensity cardiopulmonary exercise testing (CPX) could identify the most favorable physiologic combination of specific gas exchange parameters reflecting pulmonary blood flow or cardiac output, stroke volume, and left atrial pressure to guide determination of the optimal A-V interval. We assessed relative feasibility of determining the optimal A-V interval by three methods in 17 patients who underwent optimization of CRT: (1) resting echocardiographic optimization (the Ritter method), (2) resting electrical optimization (intrinsic A-V interval and QRS duration), and (3) during low-intensity, steady-state CPX. Five sequential, incremental A-V intervals were programmed in each method. Assessment of cardiopulmonary stability and potential influence on the CPX-based method were assessed. CPX and determination of a physiological optimal A-V interval was successfully completed in 94.1% of patients, slightly higher than the resting echo-based approach (88.2%). There was a wide variation in the optimal A-V delay determined by each method. There was no observed cardiopulmonary instability or impact of the implant procedure that affected determination of the CPX-based optimized A-V interval. Determining optimized A-V intervals by CPX is feasible. Proposed mechanisms explaining this finding and long-term impact require further study. ©2014 Wiley Periodicals, Inc.

[AV-reentrant tachycardia and Wolff-Parkinson-White syndrome : Diagnosis and treatment].

PubMed

Voss, Frederik; Eckardt, Lars; Busch, Sonia; Estner, Heidi L; Steven, Daniel; Sommer, Philipp; von Bary, Christian; Neuberger, Hans-Ruprecht

2016-12-01

The AV-reentrant tachycardia (AVRT) is a supraventricular tachycardia with an incidence of 1-3/1000. The pathophysiological basis is an accessory atrioventricular pathway (AP). Patients with AVRT typically present with palpitations, an on-off characteristic, anxiety, dyspnea, and polyuria. This type of tachycardia may often be terminated by vagal maneuvers. Although the clinical presentation of AVRT is quite similar to AV-nodal reentrant tachycardias, the correct diagnosis is often facilitated by analyzing a standard 12-lead ECG at normal heart rate showing ventricular preexcitation. Curative catheter ablation of the AP represents the therapy of choice in symptomatic patients. This article is the fourth part of a series written to improve the professional education of young electrophysiologists. It explains pathophysiology, symptoms, and electrophysiological findings of an invasive EP study. It focusses on mapping and ablation of accessory pathways.

Current status of the surgical treatment of atrial fibrillation.

PubMed

Geha, Alexander S; Abdelhady, Khaled

2008-03-01

Atrial fibrillation (AF) affects several million patients worldwide and is associated with a number of heart conditions, particularly coronary artery disease, rheumatic heart disease, hypertension, and congestive heart failure. The treatment of AF and its complications is quite costly. Atrial fibrillation usually results from multiple macro-re-entrant circuits in the left atrium. Very frequently, particularly in association with mitral valve disease, these circuits arise from the area of the junction of the pulmonary venous endothelium and the left atrial endocardium. Pharmacological therapy is at best 50% effective. Therapeutic options for AF include antiarrhythmic drugs, cardioversion, atrioventricular (A-V) node block, pacemaker insertion, and ablative surgery. In 1987, Cox developed an effective surgical procedure to achieve ablation. Current ablative procedures include the classic cut-and-sew Maze operation or a modification of it, namely through catheter ablation, namely, cryoablation, radiofrequency ablation (dry or irrigated), and other forms of ablation (e.g., laser, microwave). These procedures will be described, along with the indications, advantages and disadvantages of each. Special emphasis on the alternative means to cutting and sewing to achieve appropriate effective atrial scars will be stressed, and our experience with these approaches in 50 patients with AF and associated cardiac lesions and their outcomes is presented.

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.

Stereological Cell Morphometry In Right Atrium Myocardium Of Primates

NASA Astrophysics Data System (ADS)

Mandarim-De-Lacerda, Carlos A...; Hureau, Jacques

1986-07-01

The mechanism by which the cardiac impulse is propagated in normal hearts from its origin in the sinus node to the atrio-ventricular node has not been agreed on fully. We studied the "internodal posterior tract" through the crista terminalis by light microscopy and stereological morphometry. The hearts of 12 Papio cynocephalus were perfused , after sacrifice,with phosphate-buffered formol saline. The regions of the crista terminalis (CT), interatrial septum (IAS), atrioventricular bundle (AVB) and interventricular septum (IVS) were cut off and embedded in paraplast and sectioned (10 4m). The multipurpose test system M 42 was superimposed over the photomicrographs (1,890 points test, ESR = 2%) to the stereological computing. The quantitative results show that the cells from CT were more closely relationed with IAS cells than others cells (IVS and AVB cells). This results are not a morphological evidence to establish the specificity of the "internodal posterior tract". The cellular arrangement and anatomical variation in CT myocardium is very important.

Intermittent bradyarrhythmia in a Hispaniolan Amazon parrot (Amazona ventralis).

PubMed

Rembert, Melanie S; Smith, Julie A; Strickland, Keith N; Tully, Thomas N

2008-03-01

A clinically normal 2-year-old Hispaniolan Amazon parrot (Amazona ventralis) was found to have periodic second-degree atrioventricular (AV) block with variable nodal conductions while anesthetized with isoflurane during a thermal-support research project. Arrhythmias were observed on 5 successive weekly electrocardiograms. A complete cardiac evaluation, including a diagnostic electrocardiogram, revealed intermittent bradyarrhythmias ranging from a 2:1 to a 7:1 second-degree AV block, with concurrent hypotensive episodes during the nodal blocks. Results of a complete blood cell count, plasma biochemical profile, blood gas analysis, and atropine-response test, as well as radiography and auscultation, revealed no obvious cause for the arrhythmias. Echocardiography demonstrated cardiac wall thickness, chamber size, and systolic function similar to other psittacine birds. On return to the colony, the parrot continued to be outwardly asymptomatic despite the dramatic conduction disturbances. Although cardiac arrhythmias, including second-degree AV block, have been widely reported in birds, the wide variation of nodal conductions, the intermittent nature, and an arrhythmia with a 7:1 second-degree AV block that spontaneously reverts to normal as seen in this case have not been well documented in parrots.

Manual Intracardiac Electrogram Method Is Accurate Alternative to Echocardiography for Atrioventricular and Interventricular Optimization in Cardiac Resynchronization Therapy.

PubMed

Pezo Nikolić, Borka; Lovrić, Daniel; Ljubas Maček, Jana; Rešković Lukšić, Vlatka; Matasić, Richard; Šeparović Hanževački, Jadranka

2017-12-01

Some manufacturers do not provide automated intracardiac electrogram method (IEGM) systems for atrioventricular (AV) and interventricular (VV) delay optimization in cardiac resynchronization therapy (CRT). We aimed to evaluate the accuracy of manual IEGM method in 48 patients previously implanted with Medtronic Syncra CRT. All patients underwent standard device interrogation followed by CRT optimization by IEGM method and by echocardiography one month after implantation. The patient mean age was 60.7±11.8 years and there were 33 (68.8%) males. After CRT implantation, the left ventricular ejection fraction increased from 28.0±7.9% to 39.1±11.0% (p<0.001). Optimal aortic flow Velocity Time Integral (aVTI) was obtained when VV was set to 20-50 ms left ventricular pre-activation. There was a strong correlation between VV values determined by echocardiography and IEGM (R=0.823, p<0.001). We found no significant difference in AV, VV and aVTI values between echocardiography and IEGM method. However, IEGM was significantly less time-consuming than echocardiography [20 (10-28) vs. 40 (35-60) minutes, p<0.001]. Manual IEGM method may be good alternative to echocardiography and automated IEGM method. It also emphasizes the need for implementation of automated IEGM systems in as many CRT devices as possible.

Computer Three-Dimensional Reconstruction of the Atrioventricular Node

PubMed Central

Li, Jue; Greener, Ian D.; Inada, Shin; Nikolski, Vladimir P.; Yamamoto, Mitsuru; Hancox, Jules C.; Zhang, Henggui; Billeter, Rudi; Efimov, Igor R.; Dobrzynski, Halina; Boyett, Mark R.

2009-01-01

Because of its complexity, the atrioventricular node (AVN), remains 1 of the least understood regions of the heart. The aim of the study was to construct a detailed anatomic model of the AVN and relate it to AVN function. The electric activity of a rabbit AVN preparation was imaged using voltage-dependent dye. The preparation was then fixed and sectioned. Sixty-five sections at 60- to 340-μm intervals were stained for histology and immunolabeled for neurofilament (marker of nodal tissue) and connexin43 (gap junction protein). This revealed multiple structures within and around the AVN, including transitional tissue, inferior nodal extension, penetrating bundle, His bundle, atrial and ventricular muscle, central fibrous body, tendon of Todaro, and valves. A 3D anatomically detailed mathematical model (≈13 million element array) of the AVN and surrounding atrium and ventricle, incorporating all cell types, was constructed. Comparison of the model with electric activity recorded in experiments suggests that the inferior nodal extension forms the slow pathway, whereas the transitional tissue forms the fast pathway into the AVN. In addition, it suggests the pacemaker activity of the atrioventricular junction originates in the inferior nodal extension. Computer simulation of the propagation of the action potential through the anatomic model shows how, because of the complex structure of the AVN, reentry (slow-fast and fast-slow) can occur. In summary, a mathematical model of the anatomy of the AVN has been generated that allows AVN conduction to be explored. PMID:18309098

Transcatheter leadless cardiac pacing: The new alternative solution.

PubMed

Da Costa, Antoine; Axiotis, Amandine; Romeyer-Bouchard, Cécile; Abdellaoui, Loucif; Afif, Zahi; Guichard, Jean Baptiste; Gerbay, Antoine; Isaaz, Karl

2017-01-15

A lack of information about the feasibility and safety of leadless pacemaker (LPMs) exists in a fragile population of patients with limited venous anatomy access or conventional pacemaker (PM) contraindication. Accordingly, the goal of this prospective observational study was to report our experience with this new leadless technology in a subset of patients with contraindication or limited venous access. Between May 2015 and July 2016, 14 patients were consecutively included. The indications for initial PM implantation were atrioventricular (AV) block in 10/14 patients (71%), bradyarrhythmia in one (7%), and uncontrolled atrial fibrillation (AFib) requiring AV-node ablation in three (21.5%). AFib was observed in 9 of the 14 patients (64.3%) and 3 were completely dependent with no escape rhythm (21.5%). Normal access pathways via the right or left subclavian veins were occluded due to previous PM implantations and revisions in 4 patients (28.6%) and total vena cava occlusion in 3 (21.4%). End-stage renal disease with hemodialysis was present in 8 (57%) with either local-device infections or presence of long-term implanted dialysis catheters. Evidence of previous bilaterally-infected pectoral tissue was present in 3 patients (21.5%). All procedures were successful (100%) and electrical parameters remained stable over time. No direct pacemaker-related adverse events were reported, including mechanical complications, except for one ventricular fibrillation one day post-implantation under very specific conditions. This series demonstrated very stable performance and reassuring safety results during mid-term follow-up in a very fragile population requiring a PM. The Micra LPM constitutes an excellent alternative to the epicardial surgical approach in this very fragile population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Feasibility of dual-chamber (DDD) pacing via a single-pass (VDD) pacing lead employing a floating atrial ring (dipole): case series, future considerations, and refinements.

PubMed

Kassotis, John; Voigt, Louis; Mongwa, Mbu; Reddy, C V R

2005-01-01

The objective of this study was to assess the feasibility of DDD pacing from a standard single-pass VDD pacemaker system. Over the past 2 decades significant advances have been made in the development of single-pass VDD pacing systems. These have been shown in long-term prospective studies to effectively preserve atrioventricular (AV)synchrony in patients with AV block and normal sinus node function. What remains problematic is the development of a single-pass pacing system capable of DDD pacing. Such a lead configuration would be useful in those patients with peripheral venous anomalies and in younger patients with congenital anomalies, which may require lead revisions in the future. In addition, with the increased use of resynchronization (biventricular pacing) therapy, the availability of a reliable single-pass lead will minimize operative time, enhance patient safety, and minimize the amount of hardware within the heart. The feasibility of DDD pacing via a Medtronic Capsure VDD-2 (Model #5038) pacing lead was evaluated. Twenty patients who presented with AV block and normal sinus node function were recruited for this study. Atrial pacing thresholds and sensitivities were assessed intraoperatively in the supine position with various respiratory maneuvers. Five patients who agreed to participate in long-term follow-up received a dual-chamber generator and were evaluated periodically over a 12-month period. Mean atrial sensitivity was 2.35 +/- 0.83 mV at the time of implantation. Effective atrial stimulation was possible in all patients at the time of implantation (mean stimulation threshold 3.08 +/- 1.04 V at 0.5 ms [bipolar], 3.34 +/- 0.95 V at 0.5 ms [unipolar]). Five of the 20 patients received a Kappa KDR701 generator, and atrial electrical properties were followed up over a 1-year period. There was no significant change in atrial pacing threshold or incidence of phrenic nerve stimulation over the 1-year follow-up. A standard single-pass VDD pacing lead system was capable of DDD pacing intraoperatively and during long-term follow-up. Despite higher than usual thresholds via the atrial dipole, pacemaker telemetry revealed < 10% use of atrial pacing dipole over a 12-month period, which would minimally deplete the pacemaker's battery. In addition, the telemetry confirmed appropriate sensing and pacing of the atrial dipole throughout the study period. At this time such systems can serve as back-up DDD pacing systems with further refinements required to optimize atrial thresholds in all patients.

Cardiac Conduction through Engineered Tissue

PubMed Central

Choi, Yeong-Hoon; Stamm, Christof; Hammer, Peter E.; Kwaku, Kevin F.; Marler, Jennifer J.; Friehs, Ingeborg; Jones, Mara; Rader, Christine M.; Roy, Nathalie; Eddy, Mau-Thek; Triedman, John K.; Walsh, Edward P.; McGowan, Francis X.; del Nido, Pedro J.; Cowan, Douglas B.

2006-01-01

In children, interruption of cardiac atrioventricular (AV) electrical conduction can result from congenital defects, surgical interventions, and maternal autoimmune diseases during pregnancy. Complete AV conduction block is typically treated by implanting an electronic pacemaker device, although long-term pacing therapy in pediatric patients has significant complications. As a first step toward developing a substitute treatment, we implanted engineered tissue constructs in rat hearts to create an alternative AV conduction pathway. We found that skeletal muscle-derived cells in the constructs exhibited sustained electrical coupling through persistent expression and function of gap junction proteins. Using fluorescence in situ hybridization and polymerase chain reaction analyses, myogenic cells in the constructs were shown to survive in the AV groove of implanted hearts for the duration of the animal’s natural life. Perfusion of hearts with fluorescently labeled lectin demonstrated that implanted tissues became vascularized and immunostaining verified the presence of proteins important in electromechanical integration of myogenic cells with surrounding recipient rat cardiomyocytes. Finally, using optical mapping and electrophysiological analyses, we provide evidence of permanent AV conduction through the implant in one-third of recipient animals. Our experiments provide a proof-of-principle that engineered tissue constructs can function as an electrical conduit and, ultimately, may offer a substitute treatment to conventional pacing therapy. PMID:16816362

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

PubMed

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

1981-01-01

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

BMP-2 Induces Versican and Hyaluronan That Contribute to Post-EMT AV Cushion Cell Migration

PubMed Central

Inai, Kei; Burnside, Jessica L.; Hoffman, Stanley; Toole, Bryan P.; Sugi, Yukiko

2013-01-01

Distal outgrowth and maturation of mesenchymalized endocardial cushions are critical morphogenetic events during post-EMT atrioventricular (AV) valvuloseptal morphogenesis. We explored the role of BMP-2 in the regulation of valvulogenic extracellular matrix (ECM) components, versican and hyaluronan (HA), and cell migration during post-EMT AV cushion distal outgrowth/expansion. We observed intense staining of versican and HA in AV cushion mesenchyme from the early cushion expansion stage, Hamburger and Hamilton (HH) stage-17 to the cushion maturation stage, HH stage-29 in the chick. Based on this expression pattern we examined the role of BMP-2 in regulating versican and HA using 3D AV cushion mesenchymal cell (CMC) aggregate cultures on hydrated collagen gels. BMP-2 induced versican expression and HA deposition as well as mRNA expression of versican and Has2 by CMCs in a dose dependent manner. Noggin, an antagonist of BMP, abolished BMP-2-induced versican and HA as well as mRNA expression of versican and Has2. We further examined whether BMP-2-promoted cell migration was associated with expression of versican and HA. BMP-2- promoted cell migration was significantly impaired by treatments with versican siRNA and HA oligomer. In conclusion, we provide evidence that BMP-2 induces expression of versican and HA by AV CMCs and that these ECM components contribute to BMP-2-induced CMC migration, indicating critical roles for BMP-2 in distal outgrowth/expansion of mesenchymalized AV cushions. PMID:24147033

Structural and functional alterations in the atrioventricular node and atrioventricular ring tissue in ischaemia-induced heart failure.

PubMed

Yanni, Joseph; Maczewski, Michal; Mackiewicz, Urszula; Siew, Samuel; Fedorenko, Olga; Atkinson, Andrew; Price, Marcus; Beresewicz, Andrzej; Anderson, Robert H; Boyett, Mark R; Dobrzynski, Halina

2014-07-01

Heart failure (HF) causes dysfunction of the atrioventricular node (AVN) - first or second-degree heart block is a risk factor for sudden cardiac death in HF patients. The aim of the study was to determine if HF causes remodelling of the AVN and right atrioventricular ring (RAVR). HF was induced in rats (n=4) by ligation of the proximal left coronary artery, which resulted in a large infarct of the left ventricle. Sham-operated rats (n=4) were used as controls. Eight weeks after surgery, functional experiments were performed and the hearts were frozen. The body weight of HF rats was similar to control rats, but the mean heart weight of HF rats was significantly enlarged. In HF rats compared to controls, the left ventricle was dilated, left ventricular end-diastolic pressure elevated (21.0 ± 0.6 and 5.4 ± 0.2 mm Hg), left ventricular ejection fraction reduced (0.2 ± 0.02 and 0.5 ± 0.02) and left ventricular end-systolic pressure reduced (102 ± 4.2 and 127 ± 3.1 mm Hg). In HF rats, the in vivo and in vitro PR intervals were increased (41% and 20%), as was the Wenckebach cycle length, indicative of AVN dysfunction. The collagen content was significantly increased in the AVN and RAVR indicating fibrosis. Immunolabelling of caveolin3 (cell membrane marker) showed that there was hypertrophy in HF (cell diameter was increased by 63%, 39% in AVN, RAVR). The TUNEL assay showed that the myocytes of the AVN and RAVR in HF undergo apoptotic cell death. Immunolabelling showed that expression of HCN4 was significantly decreased in the AVN and RAVR (43% and 47%) in HF. We conclude that in HF there is remodelling of the AVN and RAVR and this remodelling may explain the AVN dysfunction.

Preclinical Torsades-de-Pointes screens: advantages and limitations of surrogate and direct approaches in evaluating proarrhythmic risk.

PubMed

Gintant, Gary A

2008-08-01

The successful development of novel drugs requires the ability to detect (and avoid) compounds that may provoke Torsades-de-Pointes (TdeP) arrhythmia while endorsing those compounds with minimal torsadogenic risk. As TdeP is a rare arrhythmia not readily observed during clinical or post-marketing studies, numerous preclinical models are employed to assess delayed or altered ventricular repolarization (surrogate markers linked to enhanced proarrhythmic risk). This review evaluates the advantages and limitations of selected preclinical models (ranging from the simplest cellular hERG current assay to the more complex in vitro perfused ventricular wedge and Langendorff heart preparations and in vivo chronic atrio-ventricular (AV)-node block model). Specific attention is paid to the utility of concentration-response relationships and "risk signatures" derived from these studies, with the intention of moving beyond predicting clinical QT prolongation and towards prediction of TdeP risk. While the more complex proarrhythmia models may be suited to addressing questionable or conflicting proarrhythmic signals obtained with simpler preclinical assays, further benchmarking of proarrhythmia models is required for their use in the robust evaluation of safety margins. In the future, these models may be able to reduce unwarranted attrition of evolving compounds while becoming pivotal in the balanced integrated risk assessment of advancing compounds.

Exercise capacity and N-terminal pro-brain natriuretic peptide levels with biventricular vs. right ventricular pacing for atrioventricular block: results from the PREVENT-HF German Substudy.

PubMed

Stockburger, Martin; de Teresa, Eduardo; Lamas, Gervasio; Desaga, Martin; Koenig, Carsten; Habedank, Dirk; Cobo, Erik; Navarro, Xavier; Wiegand, Uwe

2014-01-01

Previous studies showed unfavourable effects of right ventricular (RV) pacing. Ventricular pacing (VP), however, is required in many patients with atrioventricular (AV) block. The PREVENT-HF study explored left ventricular (LV) remodelling during RV vs. biventricular (BIV) pacing in AV block without advanced heart failure. The pre-specified PREVENT-HF German Substudy examined exercise capacity and N-terminal pro-brain natriuretic peptide (NT-proBNP). Patients with expected VP ≥80% were randomized to RV or BIV pacing. Endpoints were peak oxygen uptake (pVO2), oxygen uptake at the anaerobic threshold (VO2AT), ventilatory efficiency (VE/VCO2), and logNT-proBNP. Considering crossover, intention to treat (ITT), and on-treatment (OT) analyses of covariance (ANCOVA) were performed. For exercise testing 44 (RV: 25, BIV: 19), and for NT-proBNP 53 patients (RV: 29, BIV: 24) were included. The ITT analysis revealed significant differences in pVO2 [ANCOVA effect 2.83 mL/kg/min, confidence interval (CI) 0.83-4.91, P = 0.007], VO2AT (ANCOVA effect 2.14 mL/min/k, CI 0.14-4.15, P = 0.03), and VE/VCO2 (ANCOVA effect -5.46, CI -10.79 to -0.13, P = 0.04) favouring BIV randomization. The significant advantage in pVO2 persisted in OT analysis, while VO2AT and VE/VCO2 showed trends favouring BIV pacing. LogNT-proBNP did not differ between groups. (ITT: ANCOVA effect 0.008, CI -0.40 to +0.41, P = 0.97; OT: ANCOVA effect -0.03, CI -0.44 to 0.30, P = 0.90). Our study suggests that BIV pacing produces better exercise capacity over 1 year compared with RV pacing in patients without advanced heart failure and AV block. In contrast, we observed no significant changes of NT-proBNP. Larger trials will allow appraising the clinical usefulness of BIV pacing in AV block. ClinicalTrials.gov Identifier: NCT00170326.

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.

Ion Channels in the Heart

PubMed Central

Bartos, Daniel C.; Grandi, Eleonora; Ripplinger, Crystal M.

2015-01-01

Optimal cardiac function depends on proper timing of excitation and contraction in various regions of the heart, as well as on appropriate heart rate. This is accomplished via specialized electrical properties of various components of the system, including the sinoatrial node, atria, atrioventricular node, His-Purkinje system, and ventricles. Here we review the major regionally-determined electrical properties of these cardiac regions and present the available data regarding the molecular and ionic bases of regional cardiac function and dysfunction. Understanding these differences is of fundamental importance for the investigation of arrhythmia mechanisms and pharmacotherapy. PMID:26140724

Vitamin D receptor signaling is required for heart development in zebrafish embryo

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

Kwon, Hye-Joo, E-mail: hjkwon@pnu.edu.sa; Biology Department, Princess Nourah University, Riyadh 11671

Vitamin D has been found to be associated with cardiovascular diseases. However, the role of vitamin D in heart development during embryonic period is largely unknown. Vitamin D induces its genomic effects through its nuclear receptor, the vitamin D receptor (VDR). The present study investigated the role of VDR on heart development by antisense-mediated knockdown approaches in zebrafish model system. In zebrafish embryos, two distinct VDR genes (vdra and vdrb) have been identified. Knockdown of vdra has little effect on heart development, whereas disrupting vdrb gene causes various cardiac phenotypes, characterized by pericardial edema, slower heart rate and laterality defects.more » Depletion of both vdra and vdrb (vdra/b) produce additive, but not synergistic effects. To determine whether atrioventricular (AV) cardiomyocytes are properly organized in these embryos, the expression of bmp4, which marks the developing AV boundary at 48 h post-fertilization, was examined. Notably, vdra/b-deficient embryos display ectopic expression of bmp4 towards the ventricle or throughout atrial and ventricular chambers. Taken together, these results suggest that VDR signaling plays an essential role in heart development. - Highlights: • VDR signaling is involved in embryonic heart development. • Knockdown of vdrb, but not vdra, causes decreased heart rate in zebrafish embryo. • Loss of vdr results in cardiac laterality defects. • Loss of vdra/b alters atrioventricular boundary formation. • Loss of vdra/b causes abnormal cardiac looping.« less

Comparison of standard and Lewis ECG in detection of atrioventricular dissociation in patients with wide QRS tachycardia.

PubMed

Aksu, Uğur; Kalkan, Kamuran; Gülcü, Oktay; Topcu, Selim; Sevimli, Serdar; Aksakal, Enbiya; Ipek, Emrah; Açıkel, Mahmut; Tanboğa, Ibrahim Halil

2016-12-15

The atrioventricular (AV) dissociation, which is frequently used in differential diagnosis of wide QRS complex tachycardia (WQCT), is the most specific finding of ventricular tachycardia (VT) with lower sensitivity. Herein, we aimed to show the importance of Lewis lead ECG records to detect 'visible p waves' during WQCT. A total of 21 consecutive patients who underwent electrophysiologic study (EPS) were included in the study. During EPS, by using a quadripolar diagnostic catheter directed to the right ventricular apex, a fixed stimulus was given and the ventriculoatrial (VA) Wenkebach point was found, and a VT was simulated by a RV apical stimulus at 300ms. The standard and Lewis lead ECG records were taken during this procedure. We detected 'visible p waves' in 7 (33.3%) and 14 (66.7%) patients in the standard and Lewis lead ECG groups, respectively. In terms of the 'visible p waves', there was a statistically significant difference between groups (p=0.022). The sensitivity of standard and Lewis lead ECG in determination of the visible p waves was 33.3% and 66.7%, respectively. The Lewis lead ECG can be more informative about AV dissociation than the standard 12 lead ECG. As a result, we could suggest the assessment of the Lewis lead ECG recording in addition to the standard 12 lead ECG in differential diagnosis of VT in patients with WQCT. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Probable Association of Tachyarrhythmia With Nebulized Albuterol in a Child With Previously Subclinical Wolff Parkinson White Syndrome

PubMed Central

Kroesen, Michiel; Maseland, Machiel; Smal, Jaime; Reimer, Annet; van Setten, Petra

2012-01-01

We present the case of a 2-year-old asthmatic boy with atrioventricular (AV)-reentry tachycardia following albuterol inhalation, who was later diagnosed with Wolff-Parkinson-White (WPW) syndrome. The Naranjo adverse drug reaction probability scale score for this adverse event was 7, indicating that the association between his AV-reentry tachycardia and inhalation of albuterol is probable. To our knowledge, this is the first case report that shows the potential arrhythmogenic effects of albuterol in a child with WPW syndrome. We urge clinicians to be aware of this potentially life-threatening adverse effect and to closely monitor these patients when they need beta-adrenergic drugs in case of emergency. Furthermore, this report highlights the dilemma regarding the safe treatment of pediatric patients with both asthma and WPW syndrome. PMID:23118663

Near elimination of ventricular pacing in SafeR mode compared to DDD modes: a randomized study of 422 patients.

PubMed

Davy, Jean-Marc; Hoffmann, Ellen; Frey, Axel; Jocham, Kurt; Rossi, Stefano; Dupuis, Jean-Marc; Frabetti, Lorenzo; Ducloux, Pascale; Prades, Emmanuel; Jauvert, Gaël

2012-04-01

SafeR performance versus DDD/automatic mode conversion (DDD/AMC) and DDD with a 250-ms atrioventricular (AV) delay (DDD/LD) modes was assessed toward ventricular pacing (Vp) reduction. After a 1-month run-in phase, recipients of dual-chamber pacemakers without persistent AV block and persistent atrial fibrillation (AF) were randomly assigned to SafeR, DDD/AMC, or DDD/LD in a 1:1:1 design. The main endpoint was the percentage of Vp (%Vp) at 2 months and 1 year after randomization, ascertained from device memories. Secondary endpoints include %Vp at 1 year according to pacing indication and 1-year AF incidence based on automatic mode switch device stored episodes. Among 422 randomized patients (73.2±10.6 years, 50% men, sinus node dysfunction 47.4%, paroxysmal AV block 30.3%, bradycardia-tachycardia syndrome 21.8%), 141 were assigned to SafeR versus 146 to DDD/AMC and 135 to DDD/LD modes. Mean %Vp at 2 months was 3.4±12.6% in SafeR versus 33.6±34.7% and 14.0±26.0% in DDD/AMC and DDD/LD modes, respectively (P<0.0001 for both). At 1 year, mean %Vp in SafeR was 4.5±15.3% versus 37.9±34.4% and 16.7±28.0% in DDD/AMC and DDD/LD modes, respectively (P<0.0001 for both). The proportion of patients in whom Vp was completely eliminated was significantly higher in SafeR (69%) versus DDD/AMC (15%) and DDD/LD (45%) modes (P<0.0001 for both), regardless of pacing indication. The absolute risk of developing permanent AF or of remaining in AF for >30% of the time was 5.4% lower in SafeR than in the DDD pacing group (ns). In this selected patient population, SafeR markedly suppressed unnecessary Vp compared with DDD modes. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

Ablation of atrial-ventricular junction tissues via the coronary sinus using cryo balloon technology.

PubMed

Avitall, Boaz; Lafontaine, Daniel; Rozmus, Grzegorz; Adoni, Naveed; Dehnee, Abed; Urbonas, Arvydas; Le, Khoi M; Aleksonis, Dinas

2005-04-01

The coronary sinus (CS) can provide access to targets across and within the atrioventricular (AV) junction. In 12 dogs (32 +/- 3 Kg), cryo balloons (10-19 mm) were applied to regions of the AV junction for 3 minutes at a temperature of -75.9( composite function) +/- 9(composite function)C (ranging -57 to -83). Electrical activity and pacing within the CS were assessed pre and post ablation and at least 3 months later in 9 dogs. In the 3 other dogs, hearts were examined immediately after cryo ablation. CS and circumflex angiography was performed pre and post ablation. The hearts, CS, and Cx were then examined for structural injury. The AV junction was sectioned and the hearts were immersed in Tetrazolium, and the lesions were inspected for transmurality across the AV groove. In 3/12 dogs the distal CS cryo lesions resulted in inferior ST segment depression that resolved within 5 minutes. There was no arrhythmia or hemodynamic changes. No CS electrical activity was noted post ablation. The pacing threshold increased from 2 +/- 2.3 mA to 7.4 +/- 3.6 mA (p < 0.001). Pathological examination of 3 acute hearts revealed hematomas. There was no pericardial effusion. No evidence of stenosis or thrombosis was seen within the CS and the circumflex artery. After 3 months of recovery, transmural lesions across the AV groove were present in all of the targeted AV regions. Intra-CS cryo balloon ablation is safe and can potentially replace endocardial RF ablation targeting the AV junction and the CS muscular sleeve.

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.

Acquired heart block: a possible complication of patent ductus arteriosus in a preterm infant.

PubMed

Grasser, Monika; Döhlemann, Christoph; Mittal, Rashmi; Till, Holger; Dietz, Hans-Georg; Münch, Georg; Holzinger, Andreas

2008-01-01

A large patent ductus arteriosus (PDA) is a frequently encountered clinical problem in extremely low birth weight (ELBW) infants. It leads to an increased pulmonary blood flow and in a decreased or reversed diastolic flow in the systemic circulation, resulting in complications. Here we report a possible complication of PDA not previously published. On day 8 of life, a male ELBW infant (birth weight 650 g) born at a gestational age of 23 weeks and 3 days developed an atrioventricular block (AV block). The heart rate dropped from 168/min to 90/min, and the ECG showed a Wenckebach second-degree AV block and intraventricular conduction disturbances. Echocardiography demonstrated a PDA with a large left-to-right shunt and large left atrium and left ventricle with high contractility. Within several minutes after surgical closure of the PDA, the heart rate increased, and after 30 min the AV block had improved to a 1:1 conduction ratio. Echocardiography after 2 h revealed a significant decrease of the left ventricular and atrial dimensions. Within 12 h, the AV block completely reversed together with the intraventricular conduction disturbances. We suggest that PDA with a large left-to-right shunt and left ventricular volume overload may lead to an AV block in an ELBW infant. Surgical closure of the PDA may be indicated. (c) 2007 S. Karger AG, Basel.

Proposal for a new definition of congenital complete atrioventricular block.

PubMed

Brucato, A; Jonzon, A; Friedman, D; Allan, L D; Vignati, G; Gasparini, M; Stein, J I; Montella, S; Michaelsson, M; Buyon, J

2003-01-01

The classic old definition of congenital heart block by Yater (1929) is still generally accepted: 'Heart block established in a young patient. There must be some evidence of the existence of the slow pulse at a fairly early age and absence of a history of any infection which might cause the condition after birth: notably diphtheria, rheumatic fever, chorea and congenital syphilis'. However, other definitions are used. We systematically reviewed 1825 cases from 38 separate studies. We conclude that complete AV blocks detected in utero in the absence of structural abnormalities differ from blocks detected later in life with respect to pathogenesis (they are generally associated with maternal anti-Ro/SSA antibodies), poorer childhood prognosis, increased risk of developing late-onset dilated cardiomyopathy, different maternal clinical features and increased risk of recurrence in future pregnancies. For these reasons we propose a new modern definition of congenital complete AV block which might be acceptable to cardiologists, rheumatologists, pediatricians and obstetricians: 'an AV block is defined as congenital if it is diagnosed in utero, at birth or within the neonatal period (0-27 days after birth)'.

Assessment of hemodynamic load components affecting optimization of cardiac resynchronization therapy by lumped parameter mode.

PubMed

Xu, Ke; Butlin, Mark; Avolio, Alberto P

2012-01-01

Timing of biventricular pacing devices employed in cardiac resynchronization therapy (CRT) is a critical determinant of efficacy of the procedure. Optimization is done by maximizing function in terms of arterial pressure (BP) or cardiac output (CO). However, BP and CO are also determined by the hemodynamic load of the pulmonary and systemic vasculature. This study aims to use a lumped parameter circulatory model to assess the influence of the arterial load on the atrio-ventricular (AV) and inter-ventricular (VV) delay for optimal CRT performance.

Klotho protein lowered in senile patients with brady sinus arrhythmia.

PubMed

Wang, Ying; Yang, Wei; Zheng, Ernv; Zhang, Wei; Su, Xianming

2015-01-01

To explore the correlationship between brady sinus arrhythmia and the levels of serum klotho protein in aged. 104 patients over 75 years old with brady sinus arrhythmia (experiment group) were enrolled, including 34 cases of sinus arrest, 43 cases of sinus bradycardia and 25 cases of atrioventricular block. 109 patients over 75 years old without brady sinus arrhymia were chosen as control group. All subjects were monitored by Holter. The levels of serum klotho protein were detected and compared among three groups. The correlation between the frequency of sinus arrest and the levels of serum klotho protein was analyzed simultaneously. The levels of serum klotho protein in experiment group were lower than that in control group (P<0.01); the sinus arrest frequency was negatively correlated with the levels of serum klotho protien. The levels of serum klotho protein in patients with sinus arrest were lower than that with sinus bradycardia and atrioventricularblock (P<0.05). But there was no significant difference between sinus bradycardia group and atrioventricular block group. The levels of serum klotho protein may reflect the function of sinoatrial node and could be used as an index to estimate the function of sinoatrial node.

Klotho protein lowered in senile patients with brady sinus arrhythmia

PubMed Central

Wang, Ying; Yang, Wei; Zheng, Ernv; Zhang, Wei; Su, Xianming

2015-01-01

Objective: To explore the correlationship between brady sinus arrhythmia and the levels of serum klotho protein in aged. Methods: 104 patients over 75 years old with brady sinus arrhythmia (experiment group) were enrolled, including 34 cases of sinus arrest, 43 cases of sinus bradycardia and 25 cases of atrioventricular block. 109 patients over 75 years old without brady sinus arrhymia were chosen as control group. All subjects were monitored by Holter. The levels of serum klotho protein were detected and compared among three groups. The correlation between the frequency of sinus arrest and the levels of serum klotho protein was analyzed simultaneously. Results: The levels of serum klotho protein in experiment group were lower than that in control group (P<0.01); the sinus arrest frequency was negatively correlated with the levels of serum klotho protien. The levels of serum klotho protein in patients with sinus arrest were lower than that with sinus bradycardia and atrioventricularblock (P<0.05). But there was no significant difference between sinus bradycardia group and atrioventricular block group. Conclusion: The levels of serum klotho protein may reflect the function of sinoatrial node and could be used as an index to estimate the function of sinoatrial node. PMID:26550342

[The nonpharmacological treatment of tachyarrhythmias. The surgery of supraventricular arrhythmias not due to pre-excitation].

PubMed

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

1991-12-01

Surgery can provide treatment for supraventricular tachyarrhythmias without operative risk and with a definite improvement of patients' quality of life. Ectopic atrial tachycardia is a rare but invalidating arrhythmia that may lead to cardiomyopathy: intraoperative mapping is necessary for the location of the location of the ectopic focus; in our experience, surgical, cryothermal or isolation ablation of the area were effective in 9 patients out of 9, with regression of the cardiomyopathy. Atrioventricular node reentry tachycardia is a reentry tachycardia which is often associated with Wolff-Parkinson-White syndrome and is amenable to surgical treatment. Discrete cryolesions around the Koch triangle are effective in interrupting the atrial inputs to the atrioventricular node and therefore the reentry mechanism: in our experience, 7 patients were successfully treated without operative mortality: 3 patients underwent surgical ablation of Kent bundles as well. Atrial fibrillation is not based on a well-defined mechanism, and therefore does not permit an electrically-guided surgical treatment. However, in case of atrial septal defect it is possible to isolate the enlarged right atrium in order to allow sinus rhythm to activate the left atrium and ventricles.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Yagi, Yukihiro; Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama, Kanagawa 222–8567; Nakamura, Yuji

Fingolimod, a sphingosine 1-phosphate (S1P) receptor subtype 1, 3, 4 and 5 modulator, has been used for the treatment of patients with relapsing forms of multiple sclerosis, but atrioventricular conduction block and/or QT-interval prolongation have been reported in some patients after the first dose. In this study, we directly compared the electropharmacological profiles of fingolimod with those of siponimod, a modulator of sphingosine 1-phosphate receptor subtype 1 and 5, using in vivo guinea-pig model and in vitro human ether-a-go-go-related gene (hERG) assay to better understand the onset mechanisms of the clinically observed adverse events. Fingolimod (0.01 and 0.1 mg/kg) ormore » siponimod (0.001 and 0.01 mg/kg) was intravenously infused over 10 min to the halothane-anaesthetized guinea pigs (n = 4), whereas the effects of fingolimod (1 μmol/L) and siponimod (1 μmol/L) on hERG current were examined (n = 3). The high doses of fingolimod and siponimod induced atrioventricular conduction block, whereas the low dose of siponimod prolonged PR interval, which was not observed by that of fingolimod. The high dose of fingolimod prolonged QT interval, which was not observed by either dose of siponimod. Meanwhile, fingolimod significantly inhibited hERG current, which was not observed by siponimod. These results suggest that S1P receptor subtype 1 in the heart could be one of the candidates for fingolimod- and siponimod-induced atrioventricular conduction block since S1P receptor subtype 5 is localized at the brain, and that direct I{sub Kr} inhibition may play a key role in fingolimod-induced QT-interval prolongation. - Highlights: • Fingolimod and siponimod are S1P{sub 1,3,4,5} and S1P{sub 1,5} receptor modulators, respectively. • Fingolimod and siponimod induced AV block in the halothane-anesthetized guinea pigs. • S1P{sub 1} in the hearts may be the target of fingolimod- and siponimod-induced AV block. • Fingolimod directly inhibited hERG current, which was not observed by siponimod. • I{sub Kr} inhibition may play a key role in the fingolimod-induced QT prolongation.« less

Manifestations of Lyme carditis.

PubMed

Kostić, Tomislav; Momčilović, Stefan; Perišić, Zoran D; Apostolović, Svetlana R; Cvetković, Jovana; Jovanović, Andriana; Barać, Aleksandra; Šalinger-Martinović, Sonja; Tasić-Otašević, Suzana

2017-04-01

The first data of Lyme carditis, a relatively rare manifestation of Lyme disease, were published in eighties of the last century. Clinical manifestations include syncope, light-headedness, fainting, shortness of breath, palpitations, and/or chest pain. Atrioventricular (AV) electrical block of varying severity presents the most common conduction disorder in Lyme carditis. Although is usually mild, AV block can fluctuates rapidly and progress from a prolonged P-R interval to a His-Purkinje block within minutes to hours and days. Rarely, Lyme disease may be the cause of endocarditis, while some studies and reports, based on serological and/or molecular investigations, have suggested possible influence of Borrelia burgdorferi on degenerative cardiac valvular disease. Myocarditis, pericarditis, pancarditis, dilated cardiomyopathy, and heart failure have also been described as possible manifestations of Lyme carditis. The clinical course of Lyme carditis is generally mild, short term, and in most cases, completely reversible after adequate antibiotic treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Inhibition of spontaneous activity of rabbit atrioventricular node cells by KB-R7943 and inhibitors of sarcoplasmic reticulum Ca2+ ATPase

PubMed Central

Cheng, Hongwei; Smith, Godfrey L.; Hancox, Jules C.; Orchard, Clive H.

2011-01-01

The atrioventricular node (AVN) can act as a subsidiary cardiac pacemaker if the sinoatrial node fails. In this study, we investigated the effects of the Na–Ca exchange (NCX) inhibitor KB-R7943, and inhibition of the sarcoplasmic reticulum calcium ATPase (SERCA), using thapsigargin or cyclopiazonic acid (CPA), on spontaneous action potentials (APs) and [Ca2+]i transients from cells isolated from the rabbit AVN. Spontaneous [Ca2+]i transients were monitored from undialysed AVN cells at 37 °C using Fluo-4. In separate experiments, spontaneous APs and ionic currents were recorded using the whole-cell patch clamp technique. Rapid application of 5 μM KB-R7943 slowed or stopped spontaneous APs and [Ca2+]i transients. However, in voltage clamp experiments in addition to blocking NCX current (INCX) KB-R7943 partially inhibited L-type calcium current (ICa,L). Rapid reduction of external [Na+] also abolished spontaneous activity. Inhibition of SERCA (using 2.5 μM thapsigargin or 30 μM CPA) also slowed or stopped spontaneous APs and [Ca2+]i transients. Our findings are consistent with the hypothesis that sarcoplasmic reticulum (SR) Ca2+ release influences spontaneous activity in AVN cells, and that this occurs via [Ca2+]i-activated INCX; however, the inhibitory action of KB-R7943 on ICa,L means that care is required in the interpretation of data obtained using this compound. PMID:21163524

Is there a prognostic relevance of electrophysiological studies in bundle branch block patients?

PubMed

Bogossian, Harilaos; Frommeyer, Gerrit; Göbbert, Kornelius; Hasan, Fuad; Nguyen, Quy Suu; Ninios, Ilias; Mijic, Dejan; Bandorski, Dirk; Hoeltgen, Reinhard; Seyfarth, Melchior; Lemke, Bernd; Eckardt, Lars; Zarse, Markus

2017-08-01

The present European guidelines suggest a diagnostic electrophysiological (EP) study to determine indication for cardiac pacing in patients with bundle branch block and unexplained syncope. We evaluated the prognostic relevance of an EP study for mortality and the development of permanent complete atrioventricular (AV) block in patients with symptomatic bifascicular block and first-degree AV block. The HV interval is a poor prognostic marker to predict the development of permanent AV block in patients with symptomatic bifascicular block (BFB) and AV block I°. Thirty consecutive patients (mean age, 74.8 ± 8.6 years; 25 males) with symptomatic BFB and first-degree AV block underwent an EP study before device implantation, according to current guidelines. For 53 ± 31 months, patients underwent yearly follow-up screening for syncope or higher-degree AV block. Thirty patients presented with prolonged HV interval during the EP study (mean, 82.2 ± 20.1 ms; range, 57-142 ms), classified into 3 groups: group 1, <70 ms (mean, 62 ± 4 ms; range, 57-67 ms; n = 7), group 2, >70 to ≤100 ms (mean, 80 ± 8 ms; range, 70-97 ms; n = 18), and group 3, >100 ms (mean, 119 ± 14 ms; range, 107-142 ms; n = 5). According to the guidelines, patients in groups 2 and 3 received a pacemaker. The length of the HV interval was not associated with the later development of third-degree AV block or with increased mortality. Our present study suggests that an indication for pacemaker implantation based solely on a diagnostic EP study with prolongation of the HV interval is not justified. © 2017 Wiley Periodicals, Inc.

Clinical and electrophysiological characteristics of patients with paroxysmal intra-His block with narrow QRS complexes.

PubMed

Ragupathi, Loheetha; Johnson, Drew; Greenspon, Arnold; Frisch, Daniel; Ho, Reginald T; Pavri, Behzad B

2018-04-18

Atrioventricular (AV) block is usually due to infranodal disease and associated with a wide QRS complex; such patients often progress to complete AV block and pacemaker dependency. Uncommonly, infranodal AV block can occur within the His bundle with a narrow QRS complex. The aims of this study were to define clinical/echocardiographic characteristics of patients with AV block within the His bundle and report progression to pacemaker dependency. We retrospectively identified patients with narrow QRS complexes and documented intra-His delay or block at electrophysiology study (group A) or with electrocardiogram-documented Mobitz II AV block/paroxysmal AV block (group B). Clinical, electrophysiological, and echocardiographic variables at presentation and pacemaker parameters at the last follow-up visit were evaluated. Twenty-seven patients (19 women) were identified (mean age 64 ± 13 years; range, 38-85 years). Four patients who had <1 month of follow-up were excluded. There were 12 patients in group A and 11 in group B; 21 of 23 presented with syncope/presyncope. All patients received pacemakers: 8 single chamber and 15 dual chamber. After a median follow-up of 6.4 years, the median percentage of ventricular pacing was 1% (interquartile range 0%-4.66%). One patient developed true pacemaker dependency. Aortic and/or mitral annular calcification was present in 13 of 22 patients with available echocardiograms. Patients who present with syncope and narrow QRS complexes with intra-His delay or Mobitz II paroxysmal AV block with narrow QRS complexes rarely progress to pacemaker dependency and require infrequent pacing. This entity is more common in women, with a higher prevalence of aortic and/or mitral annular calcification. If confirmed by additional studies, single-chamber pacemaker may be sufficient. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Performance of a specific algorithm to minimize right ventricular pacing: A multicenter study.

PubMed

Strik, Marc; Defaye, Pascal; Eschalier, Romain; Mondoly, Pierre; Frontera, Antonio; Ritter, Philippe; Haïssaguerre, Michel; Ploux, Sylvain; Ellenbogen, Kenneth A; Bordachar, Pierre

2016-06-01

In Boston Scientific dual-chamber devices, the RYTHMIQ algorithm aims to minimize right ventricular pacing. We evaluated the performance of this algorithm determining (1) the appropriateness of the switch from the AAI(R) mode with backup VVI pacing to the DDD(R) mode in case of suspected loss of atrioventricular (AV) conduction and (2) the rate of recorded pacemaker-mediated tachycardia (PMT) when AV hysteresis searches for restored AV conduction. In this multicenter study, we included 157 patients with a Boston Scientific dual-chamber device (40 pacemakers and 117 implantable cardioverter-defibrillators) without permanent AV conduction disorder and with the RYTHMIQ algorithm activated. We reviewed the last 10 remote monitoring-transmitted RYTHMIQ and PMT episodes. We analyzed 1266 episodes of switch in 142 patients (90%): 207 (16%) were appropriate and corresponded to loss of AV conduction, and 1059 (84%) were inappropriate, of which 701 (66%) were related to compensatory pause (premature atrial contraction, 7%; premature ventricular contraction, 597 (56%); or both, 27 (3%)) or to a premature ventricular contraction falling in the post-atrial pacing ventricular refractory period interval (219, 21%) and 94 (10%) were related to pacemaker dysfunction. One hundred fifty-four PMT episodes were diagnosed in 27 patients (17%). In 85 (69%) of correctly diagnosed episodes, the onset of PMT was directly related to the algorithm-related prolongation of the AV delay, promoting AV dissociation and retrograde conduction. This study highlights some of the limitations of the RYTHMIQ algorithm: high rate of inappropriate switch and high rate of induction of PMT. This may have clinical implications in terms of selection of patients and may suggest required changes in the algorithm architecture. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Diphenylhydantoin and lidocaine modification of A-V conduction in halothane-anesthetized dogs.

PubMed

Atlee, J L; Homer, L D; Tobey, R E

1975-07-01

The effect of halothane on A-V conduction was evaluated in gods during atrial pacing using the technique of His-bundle electrocardiography. In addition, the effects of lidocaine and diphenylkydantoin (DPH) on A-V conuction were examined during halothane anesthesia. Effects of these drugs on three subintervals of A-V conduction were compared. These included the -H (stimulus atifact of His-bundle deflection-atrioventricular conduction), H-Q (His-budnle deflection onset of QRS complex-His-Purkinje conduction), and H-S intervals(His-bundle delfection to end of QRS COmplex-total intraventricular conduction). Linear regression best described the relationship between duration of interval (P-H, H-V,and H-S) and heart rate during incremental increases in the atrial paced rate. Data from these experiments were fitted to a multiple lenear regression model that predicted the effect of increasing concentrations of halothan, lidocaine, and DPH on slope and intercept coefficients. In creasing concentrations of halothan ( 30 and 45 mg/100 ml arterial). Both lidocaine and DPH further depressed conduction at all levels of halothan anesthesia. The P-H interval was particularly sensitive todrug effefts. This may represent potentiation of the normal slowing of conduction through the AVnode in response to incremental increases in heart rate (fatigue response.) We conclude thatboth lidocaine and DPH fail to reverse the depressant effect of halothane on A-V conduction. This may explain their ineffectiveness in treating certain types of arrhythmias during halothane anesthesia.

Prevention of congenital defects induced by prenatal alcohol exposure (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sheehan, Megan M.; Karunamuni, Ganga; Pedersen, Cameron J.; Gu, Shi; Doughman, Yong Qiu; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

2017-02-01

Nearly 2 million women in the United States alone are at risk for an alcohol-exposed pregnancy, including more than 600,000 who binge drink. Even low levels of prenatal alcohol exposure (PAE) can lead to a variety of birth defects, including craniofacial and neurodevelopmental defects, as well as increased risk of miscarriages and stillbirths. Studies have also shown an interaction between drinking while pregnant and an increase in congenital heart defects (CHD), including atrioventricular septal defects and other malformations. We have previously established a quail model of PAE, modeling a single binge drinking episode in the third week of a woman's pregnancy. Using optical coherence tomography (OCT), we quantified intraventricular septum thickness, great vessel diameters, and atrioventricular valve volumes. Early-stage ethanol-exposed embryos had smaller cardiac cushions (valve precursors) and increased retrograde flow, while late-stage embryos presented with gross head/body defects, and exhibited smaller atrio-ventricular (AV) valves, interventricular septum, and aortic vessels. We previously showed that supplementation with the methyl donor betaine reduced gross defects, improved survival rates, and prevented cardiac defects. Here we show that these preventative effects are also observed with folate (another methyl donor) supplementation. Folate also appears to normalize retrograde flow levels which are elevated by ethanol exposure. Finally, preliminary findings have shown that glutathione, a crucial antioxidant, is noticeably effective at improving survival rates and minimizing gross defects in ethanol-exposed embryos. Current investigations will examine the impact of glutathione supplementation on PAE-related CHDs.

Early-onset Lyme carditis with concurrent disseminated erythema migrans.

PubMed

Patel, Kinjan P; Farjo, Peter D; Juskowich, Joy J; Hama Amin, Ali; Mills, James D

2017-01-01

Lyme disease is an infection that is estimated to affect over 300,000 people in the United States annually. Typically, it presents with erythema migrans (EM), an annular rash at the site of tick attachment, within 3 to 30 days of inoculation. Untreated patients may progress to early disseminated disease. A further complication, Lyme carditis is rare but may occur several weeks later. It commonly manifests as a variable atrioventricular (AV) conduction block, with a high-grade AV block occurring in only 1% of untreated patients. This case demonstrates an unusually early presentation of Lyme carditis with complete heart block. A 21-year-old male was transferred from an outside emergency department (ED) for possible pacemaker placement due to symptomatic third-degree AV block. Four days earlier the patient presented to the outside ED with fever, chills, and unrecognized EM on his right neck. He was discharged with antipyretics, but no antibiotic therapy. On the day of transfer, he returned with persistent fevers, EM now on his trunk and upper extremities, lightheadedness, and substernal chest pressure. An electrocardiogram revealed the third-degree AV block leading to transfer. Upon arrival, the patient was promptly diagnosed with Lyme carditis. Pacemaker implantation was deferred, and intravenous (IV) ceftriaxone was initiated. Within 48 hours his third-degree AV block improved to a first-degree block. By this time, his EM had also resolved. He was discharged with oral doxycycline and a 30-day event monitor, which ultimately showed persistent first-degree AV block. This case reinforces a unique presentation of Lyme carditis. Disseminated EM and Lyme carditis may present concurrently within 2 weeks of tick attachment. Early recognition and treatment is important for preventing progression to disseminated infection. Lyme-associated AV block will reverse within 48 to 72 hours of initiating IV antibiotic therapy and will not require pacemaker implantation. Lyme carditis should be considered in patients without heart disease who present with any degree of AV block.

The systolic index: a noninvasive approach for the assessment of cardiac function: implications for patients with DDD and CRT devices.

PubMed

Chirife, Raul; Ruiz, G Aurora; Gayet, Enrique; Muratore, Claudio; Mazzetti, Héctor; Pellegrini, Alejandro; Tentori, M Cristina

2013-10-01

Our objective was to evaluate the systolic index (SI), the ratio between rate-corrected left ventricular ejection time (LVETc), and a preejection period surrogate (PEPsu), to assess cardiac function in patients with DDD and cardiac resynchronization therapy (CRT) pacemakers. LVETc and PEPsu were automatically measured from electrocardiogram and finger photoplethismography. Atrioventricular (AV) and mode switch (CRT to DDD) were used as hemodynamic challenges. Performance of SI, beat-by-beat systolic blood pressure (SBP), and Doppler aortic velocity/time integral (AoVTI) were compared in 36 patients, and SI's detection of CRT to DDD mode switch in nine patients, responders to CRT. AVs were changed from 30 ms to 250 ms (20 ms steps) at constant paced heart rate, alternating with a reference AV (RefAV), to reduce hemodynamic drift. The coefficient of variation (standard deviation/mean) of SI, SBP, and AoVTI during all RefAVs were used as error marker. The percentage detection of hemodynamic changes during AV transitions was a marker of sensitivity. Fifty-five patients (males 62%, age 69.6 ± 17) were studied. SI detected 441 of 544 transitions (81%) versus 361 (66%) of SBP (P = 0.005). Error during RefAVs was smaller for SI (3.4%) as compared to AoVTI (7.8%, P = 0.015) and to SBP (5.7%, P = 0.005). SIs correlated with AoVTI (R from 0.71 to 0.98, all P < 0.001). SI detected all CRT to DDD changes (P < 0.001). The noninvasive SI obtained with a simple, observer-independent hemodynamic assessment procedure has higher accuracy than SBP and AoVTI and better sensitivity than SBP. It detects mechanical resynchronization in CRT and allows programming a suitable AV delay. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

Case report: an unstable wide QRS complexes tachycardia after ablation of a poster-septal accessory pathway: What is the mechanism?

PubMed

Wang, Huan; Che, Xiaoru

2018-03-01

Differentiation of wide QRS complex tachycardia required repeated electrophysiological stimuli and mapping. However, instability of tachycardia would increase the difficulty in differential diagnosis. In this paper, we reported a wide QRS tachycardia following ablation of an atrioventricular reentrant tachycardia participated by a poster-septal accessory pathway. Limited differentiation strategy was performed because the wide QRS tachycardia was self-limited and with unstable hemodynamics. We analyzed the mechanism of the wide QRS tachycardia by only 4 beats ventricular overpacing. On the basis of the last ventricular pacing, an atypical atrioventricular nodal reentrant tachycardia was confirmed. After slow-pathway modification, the wide QRS tachycardia was eliminated. It was an atypical atrial-ventricular node reentrant tachycardia with right bundle branch block. Reasonable analysis based on electrophysiological electrophysiologic knowledge was the basis of successful diagnosis and treatment.

Pacemaker dependency after transcatheter aortic valve implantation with the self-expanding Medtronic CoreValve System.

PubMed

van der Boon, Robert M A; Van Mieghem, Nicolas M; Theuns, Dominic A; Nuis, Rutger-Jan; Nauta, Sjoerd T; Serruys, Patrick W; Jordaens, Luc; van Domburg, Ron T; de Jaegere, Peter P T

2013-09-30

To determine pacemaker (PM) dependency at follow-up visit in patients who underwent new permanent pacemaker implantation (PPI) following transcatheter aortic valve implantation (TAVI). Single center prospective observational study including 167 patients without previous PM implantation who underwent TAVI with the self-expanding Medtronic CoreValve System (MCS) between November 2005 and February 2011. PM dependency was defined by the presence of a high degree atrioventricular block (HDAVB; second [AV2] and third degree [AV3B]), or a slow (<30 bpm) or absent ventricular escape rhythm during follow-up PM interrogation. A total of 36 patients (21.6%) received a new PM following TAVI. The indication for PM was AV2B (n=2, 5.6%), AV3B (n=28, 77.8%), postoperative symptomatic bradycardia (n=3, 8.3%), brady-tachy syndrome (n=1, 2.8%), atrial fibrilation with slow response (n=1, 2.8%) and left bundle branch block (n=1, 2.8%). Long term follow-up was complete for all patients and ranged from 1 to 40 months (median (IQR): 11.5 (5.0-18.0 months). Of those patients with a HDAVB, 16 out of the 30 patients (53.3%) were PM independent at follow-up visit (complete or partial resolution of the AV conduction abnormality). Overall, 20 out of the 36 patients (55.6%) who received a new PM following TAVI were PM independent at follow-up. Partial and even complete resolution of peri-operative AV conduction abnormalities after MCS valve implantation occurred in more than half of the patients. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Biventricular pacing preserves left ventricular performance in patients with high-grade atrio-ventricular block: a randomized comparison with DDD(R) pacing in 50 consecutive patients.

PubMed

Albertsen, Andi E; Nielsen, Jens C; Poulsen, Steen H; Mortensen, Peter T; Pedersen, Anders K; Hansen, Peter S; Jensen, Henrik K; Egeblad, Henrik

2008-03-01

We aimed to investigate whether biventricular (BiV) pacing minimizes left ventricular (LV) dyssynchrony and preserves LV ejection fraction (LVEF) as compared with standard dual-chamber DDD(R) pacing in consecutive patients with high-grade atrio-ventricular (AV) block. Fifty patients were randomized to DDD(R) pacing or BiV pacing. LVEF was measured using three-dimensional echocardiography. Tissue-Doppler imaging was used to quantify LV dyssynchrony in terms of number of segments with delayed longitudinal contraction (DLC). LVEF was not different between groups after 12 months (P = 0.18). In the DDD(R) group LVEF decreased significantly from 59.7(57.4-61.4)% at baseline to 57.2(52.1-60.6)% at 12 months of follow-up (P = 0.03), whereas LVEF remained unchanged in the BiV group [58.9(47.1-61.7)% at baseline vs. 60.1(55.2-63.3)% after 12 months (P = 0.15)]. Dyssynchrony was more prominent in the DDD(R) group than in the BiV group at baseline (2.2 +/- 2.2 vs. 1.4 +/- 1.3 segments with DLC per patient, P = 0.10); and at 12 month follow-up (1.8 +/- 1.9 vs. 0.8 +/- 0.9 segments with DLC per patient, P = 0.02). NT-proBNP was unchanged in the DDD(R) group during follow-up (122 +/- 178 pmol/L vs. 91 +/- 166 pmol/L, NS) but decreased significantly in the BiV-group (from 198 +/- 505 pmol/L to 86 +/- 95 pmol/L after 12 months, P = 0.02). BiV pacing minimizes LV dyssynchrony, preserves LV function, and reduces NT-proBNP in contrast to DDD(R) pacing in patients with high-grade AV block.

Long-term follow-up of DDD and VDD pacing: a prospective non-randomized single-centre comparison of patients with symptomatic atrioventricular block.

PubMed

Marchandise, Sébastien; Scavée, Christophe; le Polain de Waroux, Jean-Benoit; de Meester, Christophe; Vanoverschelde, Jean-Louis; Debbas, Nadia

2012-04-01

This prospective non-randomized single-centre registry compared clinical outcome, pacing parameters, and long-term survival in patients receiving VDD or DDD pacemaker (PMs) for symptomatic atrioventricular (AV) block. Single-lead VDD (n= 166) and DDD (n= 254) PMs were implanted in 420 successive patients with isolated AV block between January 2001 and December 2009. At the end of the follow-up period [median 25 (1-141) months], there was no difference in the incidence of atrial fibrillation [11.2% in the VDD group; 11.4% in the DDD group (P= 0.95)], myocardial infarction [31.1% in the VDD group; 25.2% in the DDD group (P= 0.20)], or dilated cardiomyopathy [9.9% in the VDD group; 8.9% in the DDD group (P= 0.74)]. At last follow-up, 65.9% of the VDD PMs and 89.3% of the DDD PMs were still programmed in their original mode with good atrial sensing. Due to permanent atrial fibrillation, 7.9% patients out of the VDD group had been switched to VVIR mode and 8.7% patients out of the DDD group to VVIR or DDIR mode. The P-wave amplitude was poor (sensed P-wave <0.5 mV) in 19.1% of the VDD PM and 1.6% of the DDD PM (P< 0.001) and 7.1% of the VDD patients and 0.4% of the DDD patients had been switched to VVIR pacing mode due to P-wave undersensing and AV dissociation (P= 0.003). Symptomatic atrial undersensing requiring upgrading was similar in both groups. The overall survival, adjusted for age, was not significantly different in the VDD and the DDD group (log rank: 0.26). Moreover, Cox survival analysis excluded the pacing mode as a significant predictor of mortality [hazard ratio (HR) = 0.79, confidence interval (CI) (0.46-1.35), P= 0.39]. Comparing VDD and DDD pacing, a significantly larger number of VDD-paced patients developed poor atrial signal detection without clinical impact. However, atrial under sensing did not influence the incidence of atrial fibrillation, myocardial infarction, dilated cardiomyopathy, or mortality.

Modification of atrioventricular nodal electrophysiology by selective radiofrequency delivery on the anterior or posterior approaches.

PubMed

Chorro, F J; Sanchis, J; Such, L; Artal, L; Llavador, J J; Llavador, E; Monmeneu, J V; López-Merino, V

1997-05-01

An analysis was made in 14 isolated and perfused rabbit hearts of the electrophysiological effects of selective radiofrequency (RF) delivery in the anterior (group I, n = 7) or posterior zone (group II, n = 7) of the Koch triangle, with the aim of modifying atrioventricular nodal (AVN) conduction without suppressing 1:1 transmission. After opening the right atrium, RF was delivered (0.5 W) with a 1-mm diameter unipolar electrode positioned in the selected zone until a prolongation of no less than 15% was obtained in the Wenckebach cycle length (WCL). Before and after (30 min) RF, anterograde and retrograde AVN refractoriness and conduction were evaluated, stimulating from the crista terminalis (CT), the interatrial septum (IAS), and from the RV epicardium. After RF, the following percentage increments were observed in group I: AH(CT) = 36% +/- 9%, AH(IAS) = 38% +/- 11%, WCL(CT) = 28% +/- 8%, WCL(IAS) = 22% +/- 6%, functional refractory period (FRP) of the AVN(CT) = 13% +/- 11%, FRP-AVN(IAS) = 13% +/- 8%, retrograde WCL = 20% +/- 19%, and retrograde FRPVA = 13% +/- 16%. The increments observed in group II and the significances of the differences with respect to group I were: AH(CT) = 11% +/- 14% (P < 0.01), AH(IAS) = 19% +/- 32% (NS), WCL(CT) = 42% +/- 14% (P < 0.05), WCL(IAS) = 42% +/- 16% (P < 0.01), FRP-AVN(CT) = 28% +/- 28% (NS), FRP-AVN(LAS) = 21% +/- 19% (NS), retrograde WCL = 35% +/- 24% (NS), and retrograde FRP = 16% +/- 13% (NS). In both groups, the AH interval variations were not correlated with those of the rest of the parameters analyzed. Truncated nodal function curves suggestive of a dual AV nodal pathway were obtained in three experiments, though in only one of them was this observed under basal conditions. In the other two experiments, with dual AV nodal physiology only after RF (one from each group), AV nodal reentrant tachycardias were triggered with atrial extrastimulus at coupling intervals equal to or shorter than at those that cause a sudden lengthening of the AH interval, RF delivered in the anterior and posterior zones of the Koch triangle produced effects of different magnitude on the AH interval and Wenckebach cycle length. In the anterior zone the AH interval was prolonged to a greater extent, while in the posterior zone the effects were greater on the Wenckebach cycle length. No correlation existed between the variations in AH interval and Wenckebach cycle length, regardless of where RF was delivered. The evaluation of anterograde AV nodal refractoriness was similar when stimulating from the crista terminalis or from the interatrial septum. By delivering RF, it was possible to induce dual AV nodal physiology and reentrant tachycardias.

Electrophysiological effects of Chinese medicine Shen song Yang xin (SSYX) on Chinese miniature swine heart and isolated guinea pig ventricular myocytes.

PubMed

Feng, Li; Gong, Jing; Jin, Zhen-yi; Li, Ning; Sun, Li-ping; Wu, Yi-ling; Pu, Jie-lin

2009-07-05

Shen song Yang xin (SSYX) is a compound of Chinese medicine with the effect of increasing heart rate (HR). This study aimed to evaluate its electrophysiological properties at heart and cellular levels. The Chinese miniature swines were randomly assigned to two groups, administered with SSYX or placebo for 4 weeks (n = 8 per group). Cardiac electrophysiological study (EPS) was performed before and after drug administration. The guinea pig ventricular myocytes were enzymatically isolated and whole cell voltage-clamp technique was used to evaluate the effect of SSYX on cardiac action potential (AP). SSYX treatment accelerated the HR from (141.8 +/- 36.0) beats per minute to (163.0 +/- 38.0) beats per minute (P = 0.013) without changing the other parameters in surface electrocardiogram. After blockage of the autonomic nervous system with metoprolol and atropin, SSYX had no effect on intrinsic HR (IHR), but decreased corrected sinus node recovery time (CSNRT) and sinus atrium conducting time (SACT). Intra cardiac EPS showed that SSYX significantly decreased the A-H and A-V intervals as well as shortened the atrial (A), atrioventricular node (AVN) and ventricular (V) effective refractory period (ERP). In isolated guinea pig ventricular myocytes, the most obvious effect of SSYX on action potential was a shortening of the action potential duration (APD) without change in shape of action potential. The shortening rates of APD(30), APD(50) and APD(90) were 19.5%, 17.8% and 15.3%, respectively. The resting potential (Em) and the interval between the end of APD(30) and APD(90) did not significantly change. The present study demonstrates that SSYX increases the HR and enhances the conducting capacity of the heart in the condition of the intact autonomic nervous system. SSYX homogenously decreases the ERP of the heart and shortens the APD of the myocytes, suggesting its antiarrhythmic effect without proarrhythmia.

Towards a personalized and dynamic CRT-D. A computational cardiovascular model dedicated to therapy optimization.

PubMed

Di Molfetta, A; Santini, L; Forleo, G B; Minni, V; Mafhouz, K; Della Rocca, D G; Fresiello, L; Romeo, F; Ferrari, G

2012-01-01

In spite of cardiac resynchronization therapy (CRT) benefits, 25-30% of patients are still non responders. One of the possible reasons could be the non optimal atrioventricular (AV) and interventricular (VV) intervals settings. Our aim was to exploit a numerical model of cardiovascular system for AV and VV intervals optimization in CRT. A numerical model of the cardiovascular system CRT-dedicated was previously developed. Echocardiographic parameters, Systemic aortic pressure and ECG were collected in 20 consecutive patients before and after CRT. Patient data were simulated by the model that was used to optimize and set into the device the intervals at the baseline and at the follow up. The optimal AV and VV intervals were chosen to optimize the simulated selected variable/s on the base of both echocardiographic and electrocardiographic parameters. Intervals were different for each patient and in most cases, they changed at follow up. The model can well reproduce clinical data as verified with Bland Altman analysis and T-test (p > 0.05). Left ventricular remodeling was 38.7% and left ventricular ejection fraction increasing was 11% against the 15% and 6% reported in literature, respectively. The developed numerical model could reproduce patients conditions at the baseline and at the follow up including the CRT effects. The model could be used to optimize AV and VV intervals at the baseline and at the follow up realizing a personalized and dynamic CRT. A patient tailored CRT could improve patients outcome in comparison to literature data.

British randomised controlled trial of AV and VV optimization ("BRAVO") study: rationale, design, and endpoints.

PubMed

Whinnett, Zachary I; Sohaib, S M Afzal; Jones, Siana; Kyriacou, Andreas; March, Katherine; Coady, Emma; Mayet, Jamil; Hughes, Alun D; Frenneaux, Michael; Francis, Darrel P

2014-04-03

Echocardiographic optimization of pacemaker settings is the current standard of care for patients treated with cardiac resynchronization therapy. However, the process requires considerable time of expert staff. The BRAVO study is a non-inferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular (VV) delay with an alternative method using non-invasive blood pressure monitoring that can be automated to consume less staff resources. BRAVO is a multi-centre, randomized, cross-over, non-inferiority trial of 400 patients with a previously implanted cardiac resynchronization device. Patients are randomly allocated to six months in each arm. In the echocardiographic arm, AV delay is optimized using the iterative method and VV delay by maximizing LVOT VTI. In the haemodynamic arm AV and VV delay are optimized using non-invasive blood pressure measured using finger photoplethysmography. At the end of each six month arm, patients undergo the primary outcome measure of objective exercise capacity, quantified as peak oxygen uptake (VO2) on a cardiopulmonary exercise test. Secondary outcome measures are echocardiographic measurement of left ventricular remodelling, quality of life score and N-terminal pro B-type Natriuretic Peptide (NT-pro BNP). The study is scheduled to complete recruitment in December 2013 and to complete follow up in December 2014. If exercise capacity is non-inferior with haemodynamic optimization compared with echocardiographic optimization, it would be proof of concept that haemodynamic optimization is an acceptable alternative which has the potential to be more easily implemented. Clinicaltrials.gov NCT01258829.

Impact of Tricuspid Regurgitation on the Success of Atrioventricular Node Ablation for Rate Control in Patients With Atrial Fibrillation: The Node Blast Study.

PubMed

Reddy, Yeruva Madhu; Gunda, Sampath; Vallakati, Ajay; Kanmanthareddy, Arun; Pillarisetti, Jayasree; Atkins, Donita; Bommana, Sudharani; Emert, Martin P; Pimentel, Rhea; Dendi, Raghuveer; Berenbom, Loren D; Lakkireddy, Dhanunjaya

2015-09-15

Atrioventricular node (AVN) ablation is an effective treatment for symptomatic patients with atrial arrhythmias who are refractory to rhythm and rate control strategies where optimal ventricular rate control is desired. There are limited data on the predictors of failure of AVN ablation. Our objective was to identify the predictors of failure of AVN ablation. This is an observational single-center study of consecutive patients who underwent AVN ablation in a large academic center. Baseline characteristics, procedural variables, and outcomes of AVN ablation were collected. AVN "ablation failure" was defined as resumption of AVN conduction resulting in recurrence of either rapid ventricular response or suboptimal biventricular pacing. A total of 247 patients drug refractory AF who underwent AVN ablation at our center with a mean age of 71 ± 12 years with 46% being males were included. Ablation failure was seen in 11 (4.5%) patients. There were no statistical differences between patients with "ablation failure" versus "ablation success" in any of the baseline clinical variables. Patients with moderate-to-severe tricuspid regurgitation (TR) were much more likely to have ablation failure than those with ablation success (8 [73%] vs 65 [27%]; p = 0.003). All 11 patients with ablation failure had a successful redo procedure, 9 with right and 2 with the left sided approach. On multivariate analysis, presence of moderate-to-severe TR was found to be the only predictor of failure of AVN ablation (odds ratio 9.1, confidence interval 1.99 to 42.22, p = 0.004). In conclusion, moderate-to-severe TR is a strong and independent predictor of failure of AVN ablation. Copyright © 2015 Elsevier Inc. All rights reserved.

Rescuing cardiac automaticity in L-type Cav1.3 channelopathies and beyond.

PubMed

Mesirca, Pietro; Bidaud, Isabelle; Mangoni, Matteo E

2016-10-15

Pacemaker activity of the sino-atrial node generates the heart rate. Disease of the sinus node and impairment of atrioventricular conduction induce an excessively low ventricular rate (bradycardia), which cannot meet the needs of the organism. Bradycardia accounts for about half of the total workload of clinical cardiologists. The 'sick sinus' syndrome (SSS) is characterized by sinus bradycardia and periods of intermittent atrial fibrillation. Several genetic or acquired risk factors or pathologies can lead to SSS. Implantation of an electronic pacemaker constitutes the only available therapy for SSS. The incidence of SSS is forecast to double over the next 50 years, with ageing of the general population thus urging the development of complementary or alternative therapeutic strategies. In recent years an increasing number of mutations affecting ion channels involved in sino-atrial automaticity have been reported to underlie inheritable SSS. L-type Ca v 1.3 channels play a major role in the generation and regulation of sino-atrial pacemaker activity and atrioventricular conduction. Mutation in the CACNA1D gene encoding Ca v 1.3 channels induces loss-of-function in channel activity and underlies the sino-atrial node dysfunction and deafness syndrome (SANDD). Mice lacking Ca v 1.3 channels (Ca v 1.3 -/- ) fairly recapitulate SSS and constitute a precious model to test new therapeutic approaches to handle this disease. Work in our laboratory shows that targeting G protein-gated K + (I KACh ) channels effectively rescues SSS of Ca v 1.3 -/- mice. This new concept of 'compensatory' ion channel targeting shines new light on the principles underlying the pacemaker mechanism and may open the way to new therapies for SSS. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Higher sympathetic nerve activity during ventricular (VVI) than during dual-chamber (DDD) pacing

NASA Technical Reports Server (NTRS)

Taylor, J. A.; Morillo, C. A.; Eckberg, D. L.; Ellenbogen, K. A.

1996-01-01

OBJECTIVES: We determined the short-term effects of single-chamber ventricular pacing and dual-chamber atrioventricular (AV) pacing on directly measured sympathetic nerve activity. BACKGROUND: Dual-chamber AV cardiac pacing results in greater cardiac output and lower systemic vascular resistance than does single-chamber ventricular pacing. However, it is unclear whether these hemodynamic advantages result in less sympathetic nervous system outflow. METHODS: In 13 patients with a dual-chamber pacemaker, we recorded the electrocardiogram, noninvasive arterial pressure (Finapres), respiration and muscle sympathetic nerve activity (microneurography) during 3 min of underlying basal heart rate and 3 min of ventricular and AV pacing at rates of 60 and 100 beats/min. RESULTS: Arterial pressure was lowest and muscle sympathetic nerve activity was highest at the underlying basal heart rate. Arterial pressure increased with cardiac pacing and was greater with AV than with ventricular pacing (change in mean blood pressure +/- SE: 10 +/- 3 vs. 2 +/- 2 mm Hg at 60 beats/min; 21 +/- 5 vs. 14 +/- 2 mm Hg at 100 beats/min; p < 0.05). Sympathetic nerve activity decreased with cardiac pacing and the decline was greater with AV than with ventricular pacing (60 beats/min -40 +/- 11% vs. -17 +/- 7%; 100 beats/min -60 +/- 9% vs. -48 +/- 10%; p < 0.05). Although most patients showed a strong inverse relation between arterial pressure and muscle sympathetic nerve activity, three patients with severe left ventricular dysfunction (ejection fraction < or = 30%) showed no relation between arterial pressure and sympathetic activity. CONCLUSIONS: Short-term AV pacing results in lower sympathetic nerve activity and higher arterial pressure than does ventricular pacing, indicating that cardiac pacing mode may influence sympathetic outflow simply through arterial baroreflex mechanisms. We speculate that the greater incidence of adverse outcomes in patients treated with single-chamber ventricular rather than dual-chamber pacing may be due in part to increased sympathetic nervous outflow.

Paroxysmal supraventricular tachycardia in an octogenarian.

PubMed

Lutwak, Nancy; Dill, Curt

2012-09-01

Paroxysmal supraventricular tachycardia is a common dysrhythmia that occurs at all ages. Its management is determined by presenting symptoms and previous history of the patient. Patients present with a continuum of symptoms ranging from palpitations to syncope. The incidence of supraventricular tachycardia increases with age. To discuss the etiology, precipitating factors, and acute management of supraventricular tachycardia; and to discuss nodal reentry circuits and representative electrocardiographic findings. We present the case of an 84-year-old man with gallstone pancreatitis, choledolcholithiasis, and cholecystitis complicated by paroxysmal supraventricular tachycardia. We review this dysrhythmia, emphasizing its significance in elderly patients. Supraventricular tachycardia is a common dysrhythmia that can result in syncope or myocardial infarction. We present a case of an elderly man with new-onset atrioventricular (AV) nodal reentry tachycardia, possibly precipitated by overdrive of his autonomic nervous system due to pain and infection. As the percentage of the elderly in our population is growing rapidly and the incidence of AV nodal reentry tachycardia increases with age, emergency physicians should be familiar with this dysrhythmia-its etiology, precipitating factors, presentations, and treatment. It will present more frequently in the future. Published by Elsevier Inc.

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.

Left atrial booster function in valvular heart disease.

PubMed

Heidenreich, F P; Shaver, J A; Thompson, M E; Leonard, J J

1970-09-01

This study was designed to assess atrial booster pump action in valvular heart disease and to dissect booster pump from reservoir-conduit functions. In five patients with aortic stenosis and six with mitral stenosis, sequential atrioventricular (A-V) pacing was instituted during the course of diagnostic cardiac catheterization. Continuous recording of valvular gradient allowed estimation of flow for each cardiac cycle by transposition of the Gorlin formula. Left ventricular ejection time and left ventricular stroke work in aortic stenosis or left ventricular mean systolic pressure in mitral stenosis were also determined. Control observations were recorded during sequential A-V pacing with well-timed atrial systole. Cardiac cycles were then produced with no atrial contraction but undisturbed atrial reservoir function by intermittently interrupting the atrial pacing stimulus during sequential A-V pacing. This intervention significantly reduced valvular gradient, flow, left ventricular ejection time, and left ventricular mean systolic pressure or stroke work. Cardiac cycles were then produced with atrial booster action eliminated by instituting synchronous A-V pacing. The resultant simultaneous contraction of the atrium and ventricle not only eliminated effective atrial systole but also placed atrial systole during the normal period of atrial reservoir function. This also significantly reduced all the hemodynamic measurements. However, comparison of the magnitude of change from these two different pacing interventions showed no greater impairment of hemodynamic state when both booster pump action and reservoir function were impaired than when booster pump action alone was impaired. The study confirms the potential benefit of well placed atrial booster pump action in valvular heart disease in man.

Betaine supplementation reduces congenital defects after prenatal alcohol exposure (Conference Presentation)

NASA Astrophysics Data System (ADS)

Karunamuni, Ganga; Gu, Shi; Doughman, Yong Qiu; Sheehan, Megan M.; Ma, Pei; Peterson, Lindsy M.; Linask, Kersti K.; Jenkins, Michael W.; Rollins, Andrew M.; Watanabe, Michiko

2016-03-01

Over 500,000 women per year in the United States drink during pregnancy, and 1 in 5 of this population also binge drink. As high as 20-50% of live-born children with prenatal alcohol exposure (PAE) present with congenital heart defects including outflow and valvuloseptal anomalies that can be life-threatening. Previously we established a model of PAE (modeling a single binge drinking episode) in the avian embryo and used optical coherence tomography (OCT) imaging to assay early-stage cardiac function/structure and late-stage cardiac defects. At early stages, alcohol/ethanol-exposed embryos had smaller cardiac cushions and increased retrograde flow. At late stages, they presented with gross morphological defects in the head and chest wall, and also exhibited smaller or abnormal atrio-ventricular (AV) valves, thinner interventricular septae (IVS), and smaller vessel diameters for the aortic trunk branches. In other animal models, the methyl donor betaine (found naturally in many foods such as wheat bran, quinoa, beets and spinach) ameliorates neurobehavioral deficits associated with PAE but the effects on heart structure are unknown. In our model of PAE, betaine supplementation led to a reduction in gross structural defects and appeared to protect against certain types of cardiac defects such as ventricular septal defects and abnormal AV valvular morphology. Furthermore, vessel diameters, IVS thicknesses and mural AV leaflet volumes were normalized while the septal AV leaflet volume was increased. These findings highlight the importance of betaine and potentially methylation levels in the prevention of PAE-related birth defects which could have significant implications for public health.

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

PubMed

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

2018-04-01

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

Pacemaker Dependency after Cardiac Surgery: A Systematic Review of Current Evidence.

PubMed

Steyers, Curtis M; Khera, Rohan; Bhave, Prashant

2015-01-01

Severe postoperative conduction disturbances requiring permanent pacemaker implantation frequently occur following cardiac surgery. Little is known about the long-term pacing requirements and risk factors for pacemaker dependency in this population. We performed a systematic review of the literature addressing rates and predictors of pacemaker dependency in patients requiring permanent pacemaker implantation after cardiac surgery. Using a comprehensive search of the Medline, Web of Science and EMBASE databases, studies were selected for review based on predetermined inclusion and exclusion criteria. A total of 8 studies addressing the endpoint of pacemaker-dependency were identified, while 3 studies were found that addressed the recovery of atrioventricular (AV) conduction endpoint. There were 10 unique studies with a total of 780 patients. Mean follow-up ranged from 6-72 months. Pacemaker dependency rates ranged from 32%-91% and recovery of AV conduction ranged from 16%-42%. There was significant heterogeneity with respect to the definition of pacemaker dependency. Several patient and procedure-specific variables were found to be independently associated with pacemaker dependency, but these were not consistent between studies. Pacemaker dependency following cardiac surgery occurs with variable frequency. While individual studies have identified various perioperative risk factors for pacemaker dependency and non-resolution of AV conduction disease, results have been inconsistent. Well-conducted studies using a uniform definition of pacemaker dependency might identify patients who will benefit most from early permanent pacemaker implantation after cardiac surgery.

Cardiac arrhythmias during or after epileptic seizures

PubMed Central

van der Lende, Marije; Surges, Rainer; Sander, Josemir W; Thijs, Roland D

2016-01-01

Seizure-related cardiac arrhythmias are frequently reported and have been implicated as potential pathomechanisms of Sudden Unexpected Death in Epilepsy (SUDEP). We attempted to identify clinical profiles associated with various (post)ictal cardiac arrhythmias. We conducted a systematic search from the first date available to July 2013 on the combination of two terms: ‘cardiac arrhythmias’ and ‘epilepsy’. The databases searched were PubMed, Embase (OVID version), Web of Science and COCHRANE Library. We attempted to identify all case reports and case series. We identified seven distinct patterns of (post)ictal cardiac arrhythmias: ictal asystole (103 cases), postictal asystole (13 cases), ictal bradycardia (25 cases), ictal atrioventricular (AV)-conduction block (11 cases), postictal AV-conduction block (2 cases), (post)ictal atrial flutter/atrial fibrillation (14 cases) and postictal ventricular fibrillation (3 cases). Ictal asystole had a mean prevalence of 0.318% (95% CI 0.316% to 0.320%) in people with refractory epilepsy who underwent video-EEG monitoring. Ictal asystole, bradycardia and AV-conduction block were self-limiting in all but one of the cases and seen during focal dyscognitive seizures. Seizure onset was mostly temporal (91%) without consistent lateralisation. Postictal arrhythmias were mostly found following convulsive seizures and often associated with (near) SUDEP. The contrasting clinical profiles of ictal and postictal arrhythmias suggest different pathomechanisms. Postictal rather than ictal arrhythmias seem of greater importance to the pathophysiology of SUDEP. PMID:26038597

Morphological study of the atrioventricular conduction system and Purkinje fibers in yak.

PubMed

Duan, Deyong; Yu, Sijiu; Cui, Yan; Li, Chaoxu

2017-07-01

We studied the morphology of the atrioventricular conduction system (AVCS) and Purkinje fibers of the yak. Light and transmission electron microscopy were used to study the histological features of AVCS. The distributional characteristics of the His-bundle, the left bundle branch (LBB), right bundle branch (RBB), and Purkinje fiber network of yak hearts were examined using gross dissection, ink injection, and ABS casting. The results showed that the atrioventricular node (AVN) of yak located in the right side of interatrial septum and had a flattened ovoid shape. The AVN of yak is composed of the slender, interweaving cells formed almost entirely of the transitional cells (T-cells). The His-bundle extended from the AVN, and split into left LBB and RBB at the crest of the interventricular septum. The LBB descended along the left side of interventricular septum. At approximately the upper 1/3 of the interventricular septum, the LBB typically divided into three branches. The RBB ran under the endocardium of the right side of interventricular septum, and extended to the base of septal papillary muscle, passed into the moderator band, crossed the right ventricular cavity to reach the base of anterior papillary muscle, and divided into four fascicles under the subendocardial layer. The Purkinje fibers in the ventricle formed a complex spatial network. The distributional and cellular component characteristics of the AVCS and Purkinje fibers ensured normal cardiac function. © 2017 Wiley Periodicals, Inc.

Atrial Fibrillation

MedlinePlus

... the signal slows down slightly, allowing the ventricles time to finish filling with blood. The electrical signal then leaves the AV node and travels to the ventricles. It causes the ventricles to ...

Automated classification and quantitative analysis of arterial and venous vessels in fundus images

NASA Astrophysics Data System (ADS)

Alam, Minhaj; Son, Taeyoon; Toslak, Devrim; Lim, Jennifer I.; Yao, Xincheng

2018-02-01

It is known that retinopathies may affect arteries and veins differently. Therefore, reliable differentiation of arteries and veins is essential for computer-aided analysis of fundus images. The purpose of this study is to validate one automated method for robust classification of arteries and veins (A-V) in digital fundus images. We combine optical density ratio (ODR) analysis and blood vessel tracking algorithm to classify arteries and veins. A matched filtering method is used to enhance retinal blood vessels. Bottom hat filtering and global thresholding are used to segment the vessel and skeleton individual blood vessels. The vessel tracking algorithm is used to locate the optic disk and to identify source nodes of blood vessels in optic disk area. Each node can be identified as vein or artery using ODR information. Using the source nodes as starting point, the whole vessel trace is then tracked and classified as vein or artery using vessel curvature and angle information. 50 color fundus images from diabetic retinopathy patients were used to test the algorithm. Sensitivity, specificity, and accuracy metrics were measured to assess the validity of the proposed classification method compared to ground truths created by two independent observers. The algorithm demonstrated 97.52% accuracy in identifying blood vessels as vein or artery. A quantitative analysis upon A-V classification showed that average A-V ratio of width for NPDR subjects with hypertension decreased significantly (43.13%).

Excitation model of pacemaker cardiomyocytes of cardiac conduction system

NASA Astrophysics Data System (ADS)

Grigoriev, M.; Babich, L.

2015-11-01

Myocardium includes typical and atypical cardiomyocytes - pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation - heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.

Inhibition of sarcoplasmic reticulum Ca(2+)-ATPase decreases atrioventricular node-paced heart rate in rabbits.

PubMed

Cheng, Hongwei; Smith, Godfrey L; Orchard, Clive H; Hancox, Jules C; Burton, Francis L

2012-10-01

Recent data indicate that Ca(2+) cycling in isolated atrioventricular node (AVN) cells contributes to setting spontaneous rate. The aim of the present study was to extend this observation to the intact AVN in situ, by evaluating the effects of inhibiting sarcoplasmic reticulum Ca(2+) uptake with cyclopiazonic acid (CPA) on intact AVN spontaneous activity and its response to isoprenaline. A model of the AVN-paced heart was produced to investigate intact AVN automaticity, by surgical ablation of the sino-atrial node (SAN) in the rabbit Langendorff-perfused heart. Electrograms were recorded from a site close to the AVN (triangle of Koch), an atrial site above the AVN, the left atrium and right ventricle, enabling AVN pacing of the preparation to be confirmed. Before SAN ablation, the heart rate was 166.8 ± 5.4 beats min(-1). Ablation of the SAN was clearly indicated by a sudden and significant decrease of heart rate to 108.6 ± 9.6 beats min(-1) (P < 0.01, n = 10). Isoprenaline (100 nm) increased AVN rate to 187.8 ± 12.0 beats min(-1) after 1 min of application (P < 0.01, n = 10). Cyclopiazonic acid (10 and 30 μm) decreased AVN rate to 81.6 ± 4.8 (n = 9) and 77.4 ± 6.0 beats min(-1) (n = 7), respectively [P < 0.05, 10 or 30 μm CPA versus control (n = 10)] and also reduced the AVN rate increase in response to isoprenaline from 78.8 ± 10.0 to 46.8 ± 6.8 and 26.7 ± 5.3%, respectively (P < 0.01). These inhibitory effects of CPA on the intact AVN rate and its response to isoprenaline indicate that Ca(2+) cycling is important to the intact AVN spontaneous activity and its acceleration during sympathetic stimulation.

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

PubMed

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

2017-09-01

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

Acute desensitization of acetylcholine and endothelin-1 activated inward rectifier K+ current in myocytes from the cardiac atrioventricular node.

PubMed

Choisy, Stéphanie C M; James, Andrew F; Hancox, Jules C

2012-07-06

The atrioventricular node (AVN) is a vital component of the pacemaker-conduction system of the heart, co-ordinating conduction of electrical excitation from cardiac atria to ventricles and acting as a secondary pacemaker. The electrical behaviour of the AVN is modulated by vagal activity via activation of muscarinic potassium current, IKACh. However, it is not yet known if this response exhibits 'fade' or desensitization in the AVN, as established for the heart's primary pacemaker--the sinoatrial node. In this study, acute activation of IKACh in rabbit single AVN cells was investigated using whole-cell patch clamp at 37 °C. 0.1-1 μM acetylcholine (ACh) rapidly activated a robust IKACh in AVN myocytes during a descending voltage-ramp protocol. This response was inhibited by tertiapin-Q (TQ; 300 nM) and by the M2 muscarinic ACh receptor antagonist AFDX-116 (1 μM). During sustained ACh exposure the elicited IKACh exhibited bi-exponential fade (τf of 2.0 s and τs 76.9 s at -120 mV; 1 μM ACh). 10 nM ET-1 elicited a current similar to IKACh, which faded with a mono-exponential time-course (τ of 52.6 s at -120 mV). When ET-1 was applied following ACh, the ET-1 activated response was greatly attenuated, demonstrating that ACh could desensitize the response to ET-1. For neither ACh nor ET-1 was the rate of current fade dependent upon the initial response magnitude, which is inconsistent with K+ flux mediated changes in electrochemical driving force as the underlying mechanism. Collectively, these findings demonstrate that TQ sensitive inwardly rectifying K+ current in cardiac AVN cells, elicited by M2 muscarinic receptor or ET-1 receptor activation, exhibits fade due to rapid desensitization. Copyright © 2012 Elsevier Inc. All rights reserved.

Frailty syndrome in patients with heart rhythm disorders.

PubMed

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

2017-09-01

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

Noninvasive, automatic optimization strategy in cardiac resynchronization therapy.

PubMed

Reumann, Matthias; Osswald, Brigitte; Doessel, Olaf

2007-07-01

Optimization of cardiac resynchronization therapy (CRT) is still unsolved. It has been shown that optimal electrode position,atrioventricular (AV) and interventricular (VV) delays improve the success of CRT and reduce the number of non-responders. However, no automatic, noninvasive optimization strategy exists to date. Cardiac resynchronization therapy was simulated on the Visible Man and a patient data-set including fiber orientation and ventricular heterogeneity. A cellular automaton was used for fast computation of ventricular excitation. An AV block and a left bundle branch block were simulated with 100%, 80% and 60% interventricular conduction velocity. A right apical and 12 left ventricular lead positions were set. Sequential optimization and optimization with the downhill simplex algorithm (DSA) were carried out. The minimal error between isochrones of the physiologic excitation and the therapy was computed automatically and leads to an optimal lead position and timing. Up to 1512 simulations were carried out per pathology per patient. One simulation took 4 minutes on an Apple Macintosh 2 GHz PowerPC G5. For each electrode pair an optimal pacemaker delay was found. The DSA reduced the number of simulations by an order of magnitude and the AV-delay and VV - delay were determined with a much higher resolution. The findings are well comparable with clinical studies. The presented computer model of CRT automatically evaluates an optimal lead position and AV-delay and VV-delay, which can be used to noninvasively plan an optimal therapy for an individual patient. The application of the DSA reduces the simulation time so that the strategy is suitable for pre-operative planning in clinical routine. Future work will focus on clinical evaluation of the computer models and integration of patient data for individualized therapy planning and optimization.

Implantable defibrillators configured for hybrid therapy of persistent and permanent atrial fibrillation: initial clinical experience with a novel lead system.

PubMed

Rao, Hygriv B; Saksena, Sanjeev

2005-08-01

Hybrid therapy strategies have combined antiarrhythmic drugs (AAD) with pacemakers, atrio-ventricular defibrillators (AV ICD) or atrial ablation individually. The feasibility combining AAD with dual site RA pacing (DAP) in an AV ICD has not been examined. We used an AV ICD with a novel lead configuration permitting DAP, antitachycardia pacing (ATP) or atrial shocks (ADF) in patients (pts) with refractory persistent or permanent AF. Hybrid therapy included linear RA ablation and/or focal ablation. Continuous DAP and automatic ATP with patient or physician activated ADF. 24 pts, mean age 66 +/- 10 yrs, with cardiac disease (22 pts), underwent insertion of an AVICD with dual RA leads. 20 patients had concomitant ablative procedures (RA only = 19, RA + LA = 1) and all pts continued previously ineffective AAD. During a follow-up of 2-36 months (mean 17 +/- 8 mos), rhythm control was restored in all pts & maintained long-term in 19 (83%) pts. 8 pts used AF termination therapies successfully. Device datalogs showed no episodes of AF in 6 pts, asymptomatic brief arrhythmias in 4 pts, infrequent paroxysmal AF in 9 pts & persistent AF recurred in 5 pts. AV ICD detection algorithms reliably detected AF or AT in the DAP mode in all pts. Intermittent brief P wave double counting occurred during AT in selected pts. No pt received inappropriate ADF therapy. 1. DAP can be safely incorporated in an AVICD devices for use in an hybrid therapy strategy for AF pts. 2. These devices can be effective for both AF prevention & termination. 3. Long term rhythm control can be achieved and documented by device datalogs in persistent and permanent AF.

Impact of early initiation of corticosteroid therapy on cardiac function and rhythm in patients with cardiac sarcoidosis.

PubMed

Padala, Santosh K; Peaslee, Samuel; Sidhu, Mandeep S; Steckman, David A; Judson, Marc A

2017-01-15

There is limited data on the effect of corticosteroid therapy in patients with cardiac sarcoidosis (CS). We sought to examine the impact of early initiation of corticosteroid therapy, within a month of CS diagnosis, on left ventricular ejection fraction (LVEF), ventricular arrhythmias (VAs), and atrioventricular (AV) block. We retrospectively identified 30 CS patients from a large university sarcoidosis clinic. The effect of early initiation of corticosteroid therapy on LVEF was assessed by serial echocardiography, and on VAs and AV block was assessed by Holter monitoring and/or device interrogations. The median time from diagnosis of extra-cardiac sarcoidosis to CS was 40months. 90% (27/30) of the CS patients received corticosteroid therapy and 85% percent (23/27) had early initiation of corticosteroid therapy. Fourteen patients (47%) had reduced EF<50%. 9/14 patients who had early initiation of corticosteroid therapy had improvement in mean EF (25% to 46%, P<0.001); 5/14 patients who had a delay in initiation or who did not receive corticosteroids had no improvement in mean EF (41% to 37%, P=0.47). Fourteen patients (47%) had VAs and 5 patients (17%) had advanced AV block. Early initiation of corticosteroid therapy resulted in no VA recurrences in 8/11 patients (72%), and complete recovery of AV conduction in 2/3 patients (67%). Patients with VAs (n=3) or advanced AV block (n=2) who failed to receive early corticosteroid therapy did not show improvement. There is often a delay in manifestation of cardiac sarcoidosis for several years from the diagnosis of extra-cardiac sarcoidosis. Prompt initiation of corticosteroid therapy in CS patients may improve outcomes whereas delayed initiation of corticosteroids or failure to use corticosteroids may be associated with worse outcomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The History of the Wolff–Parkinson–White Syndrome

PubMed Central

Scheinman, Melvin M.

2012-01-01

While Drs Wolff, Parkinson, and White fully described the syndrome in 1930, prior case reports had described the essentials. Over the ensuing century this syndrome has captivated the interest of anatomists, clinical cardiologists, and cardiac surgeons. Stanley Kent described lateral muscular connections over the atrioventricular (AV) groove which he felt were the normal AV connections. The normal AV connections were, however, clearly described by His and Tawara. True right-sided AV connections were initially described by Wood et al., while Öhnell first described left free wall pathways. David Scherf is thought to be the first to describe our current understanding of the pathogenesis of the WPW syndrome in terms of a re-entrant circuit involving both the AV node–His axis as well as the accessory pathway. This hypothesis was not universally accepted, and many theories were applied to explain the clinical findings. The basics of our understanding were established by the brilliant work of Pick, Langendorf, and Katz who by using careful deductive analysis of ECGs were able to define the basic pathophysiological processes. Subsequently, Wellens and Durrer applied invasive electrical stimulation to the heart in order to confirm the pathophysiological processes. Sealy and his colleagues at Duke University Medical Center were the first to successfully surgically divide an accessory pathway and ushered in the modern era of therapy for these patients. Morady and Scheinman were the first to successfully ablate an accessory pathway (posteroseptal) using high-energy direct-current shocks. Subsequently Jackman, Kuck, Morady, and a number of groups proved the remarkable safety and efficiency of catheter ablation for pathways in all locations using radiofrequency energy. More recently, Gollob et al. first described the gene responsible for a familial form of WPW. The current ability to cure patients with WPW is due to the splendid contributions of individuals from diverse disciplines throughout the world. PMID:23908843

Positive and negative gain exceeding unity magnitude in silicon quantum well metal-oxide-semiconductor transistors

NASA Astrophysics Data System (ADS)

Hu, Gangyi; Wijesinghe, Udumbara; Naquin, Clint; Maggio, Ken; Edwards, H. L.; Lee, Mark

2017-10-01

Intrinsic gain (AV) measurements on Si quantum well (QW) n-channel metal-oxide-semiconductor (NMOS) transistors show that these devices can have |AV| > 1 in quantum transport negative transconductance (NTC) operation at room temperature. QW NMOS devices were fabricated using an industrial 45 nm technology node process incorporating ion implanted potential barriers to define a lateral QW in the conduction channel under the gate. While NTC at room temperature arising from transport through gate-controlled QW bound states has been previously established, it was unknown whether the quantum NTC mechanism could support gain magnitude exceeding unity. Bias conditions were found giving both positive and negative AV with |AV| > 1 at room temperature. This result means that QW NMOS devices could be useful in amplifier and oscillator applications.

[Permanent cardiac pacing for chronic symptomatic atrioventricular block in uremic hemodialysed patients. A prospective study].

PubMed

Arsenescu, Cătălina; Georgescu, G I M; Covic, A; Briotă, Laura

2002-01-01

Though sudden cardiac death accounts for as much as 15% of all cause mortality in uremia, reports concerning advanced A-V block, requiring permanent cardiac pacing in end-stage renal disease (ESRD) hemodialysed (HD) patients are very few. This is the first long term prospective study reporting on systematic permanent pacemaker implantation, in a cohort of ESRD patients from a single HD unit. Between 01/06/1997 and 30/12/2001, 396 pacemakers were inserted for advanced, symptomatic A-V block in our institution, including 5 in ESRD, HD patients (M/F--4/1, age 47-73, M +/- SD--61 +/- 12 years) from a single dialysis center, treating 137 patients during the study period. Thus, the incidence and prevalence of A-V defects treated by permanent pacing in uremic patients was 0.81% and 3.65% respectively. Conversely, the incidence and prevalence of ESRD treated by hemodialysis, among patients with advanced A-V conduction disturbances, requiring permanent pacing were 0.28% and 1.26%. Mitral valve calcifications were present in all patients; 3 subjects also had extensive aortic valve calcifications. Left ventricular hypertrophy (echocardiographic Framingham criteria) was present in 4 patients, but the systolic function (ejection fraction and fractional shortening index) was normal in all cases, although a clinical picture of chronic heart failure was seen in 3 subjects preoperatively. A-V conduction defects were attributed to extensive metastatic calcifications, involving the cardiac squeleton, consecutive to severe hyperparathyroidism and inadvertent use of calcitriol and calcium carbonate as phosphate binders. No technical difficulties, short or long-term complications related to pacemaker implantation (4 VVI and 1 VVD devices) were encountered. Acute threshold and sensing values were similar with those of non-uremic patients. During follow-up, one patients died from a non cardiac death. If optimal hemodialysis is provided, benefits of permanent pacing are equal in uremic or non uremic patients and pacemaker implantation should be instituted as a prompt life-saving method in all dialysis patients with chronic symptomatic advanced A-V blocks.

Pacemaker Dependency after Cardiac Surgery: A Systematic Review of Current Evidence

PubMed Central

2015-01-01

Background Severe postoperative conduction disturbances requiring permanent pacemaker implantation frequently occur following cardiac surgery. Little is known about the long-term pacing requirements and risk factors for pacemaker dependency in this population. Methods We performed a systematic review of the literature addressing rates and predictors of pacemaker dependency in patients requiring permanent pacemaker implantation after cardiac surgery. Using a comprehensive search of the Medline, Web of Science and EMBASE databases, studies were selected for review based on predetermined inclusion and exclusion criteria. Results A total of 8 studies addressing the endpoint of pacemaker-dependency were identified, while 3 studies were found that addressed the recovery of atrioventricular (AV) conduction endpoint. There were 10 unique studies with a total of 780 patients. Mean follow-up ranged from 6–72 months. Pacemaker dependency rates ranged from 32%-91% and recovery of AV conduction ranged from 16%-42%. There was significant heterogeneity with respect to the definition of pacemaker dependency. Several patient and procedure-specific variables were found to be independently associated with pacemaker dependency, but these were not consistent between studies. Conclusions Pacemaker dependency following cardiac surgery occurs with variable frequency. While individual studies have identified various perioperative risk factors for pacemaker dependency and non-resolution of AV conduction disease, results have been inconsistent. Well-conducted studies using a uniform definition of pacemaker dependency might identify patients who will benefit most from early permanent pacemaker implantation after cardiac surgery. PMID:26470027

Learning electrocardiogram on YouTube: how useful is it?

PubMed

Akgun, Taylan; Karabay, Can Yucel; Kocabay, Gonenc; Kalayci, Arzu; Oduncu, Vecih; Guler, Ahmet; Pala, Selcuk; Kirma, Cevat

2014-01-01

YouTube has become a useful resource for knowledge and is widely used by medical students as an e-learning source. The purpose of this study was to assess the videos relating electrocardiogram (ECG) on YouTube. YouTube was searched on May 28, 2013 for the search terms "AF ecg" for atrial fibrillation, "AVNRT" for atrioventricular nodal reentrant tachycardia, "AVRT" for atrioventricular reentrant tachycardia, "AV block or heart block" for atrioventricular block, "LBBB, RBBB" for bundle branch block, "left anterior fascicular block or left posterior fascicular block" for fascicular blocks, "VT ecg" for ventricular tachycardia, "long QT" and "Brugada ecg". Non-English language, unrelated and non-educational videos were excluded. Remaining videos were assessed for usefulness, source and characteristics. Usefulness was assessed with using a checklist developed by the authors. One hundred nineteen videos were included in the analysis. Sources of the videos were as follows: individuals n=70, 58.8%, universities/hospitals n=10, 8.4% and medical organizations n=3, 2.5%, health ads n=10 8.4%, health websites n=26, 21.8%. Fifty-six (47.1%) videos were classified as very useful and 16 (13.4%) videos were misleading. 90% of the videos uploaded by universities/hospitals were grouped as very useful videos, the same ratio was 45% for the individual uploads. There were statistically significant differences in ECG diagnosis among the groups (for very useful, useful and misleading, p<0.001, 0.02 and 0.008, respectively). The ratio of the misleading information in ventricular tachycardia videos was found to be 42.9%. YouTube has a substantial amount of videos on ECG with a wide diversity from useful to misleading content. The lack of quality content relating to ECG on YouTube necessitates that videos should be selected with utmost care. © 2013 Elsevier Inc. All rights reserved.

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

PubMed

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

1988-04-01

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

Spinal Anaesthesia is Safe in a Patient with Wolff-Parkinson-White Syndrome Undergoing Evacuation of Molar Pregnancy.

PubMed

Deviseti, Pravalika; Pujari, Vinayak S

2016-02-01

Wolff-Parkinson-White (WPW) syndrome is an uncommon cardiac condition where there is an abnormal band of atrial tissue connecting atria and ventricles which can electrically bypass atrioventricular node. The anaesthetic management in these patients is challenging as life threatening complications can occur perioperatively like paroxysmal supraventricular tachycardia and atrial fibrillation. Also, regional anaesthetic technique like subarachnoid block is a safe and cost effective alternative to general anaesthesia as it avoids polypharmacy. We report the successful anaesthetic management of Wolff Parkinson White syndrome in a primi with hydatiform mole posted for suction and evacuation.

A Parametric Computational Model of the Action Potential of Pacemaker Cells.

PubMed

Ai, Weiwei; Patel, Nitish D; Roop, Partha S; Malik, Avinash; Andalam, Sidharta; Yip, Eugene; Allen, Nathan; Trew, Mark L

2018-01-01

A flexible, efficient, and verifiable pacemaker cell model is essential to the design of real-time virtual hearts that can be used for closed-loop validation of cardiac devices. A new parametric model of pacemaker action potential is developed to address this need. The action potential phases are modeled using hybrid automaton with one piecewise-linear continuous variable. The model can capture rate-dependent dynamics, such as action potential duration restitution, conduction velocity restitution, and overdrive suppression by incorporating nonlinear update functions. Simulated dynamics of the model compared well with previous models and clinical data. The results show that the parametric model can reproduce the electrophysiological dynamics of a variety of pacemaker cells, such as sinoatrial node, atrioventricular node, and the His-Purkinje system, under varying cardiac conditions. This is an important contribution toward closed-loop validation of cardiac devices using real-time heart models.

Pacemaker Use in New Zealand - Data From the New Zealand Implanted Cardiac Device Registry (ANZACS-QI 15).

PubMed

Larsen, P D; Kerr, A J; Hood, M; Harding, S A; Hooks, D; Heaven, D; Lever, N A; Sinclair, S; Boddington, D; Tang, E W; Swampillai, J; Stiles, M K

2017-03-01

The New Zealand Cardiac Implanted Device Registry (Device) has recently been developed under the auspices of the New Zealand Branch of the Cardiac Society of Australia and New Zealand. This study describes the initial Device registry cohort of patients receiving a new pacemaker, their indications for pacing and their perioperative complications. The Device Registry was used to audit patients receiving a first pacemaker between 1 st January 2014 and 1 st June 2015. We examined 1611 patients undergoing first pacemaker implantation. Patients were predominantly male (59%), and had a median age of 70 years. The most common symptom for pacemaker implantation was syncope (39%), followed by dizziness (30%) and dyspnoea (12%). The most common aetiology for a pacemaker was a conduction tissue disorder (35%), followed by sinus node dysfunction (22%). Atrioventricular (AV) block was the most common ECG abnormality, present in 44%. Dual chamber pacemakers were most common (62%), followed by single chamber ventricular pacemakers (34%), and cardiac resynchronisation therapy - pacemakers (CRT-P) (2%). Complications within 24hours of the implant procedure were reported in 64 patients (3.9%), none of which were fatal. The most common complication was the need for reoperation to manipulate a lead, occurring in 23 patients (1.4%). This is the first description of data entered into the Device registry. Patients receiving a pacemaker were younger than in European registries, and there was a low use of CRT-P devices compared to international rates. Complications rates were low and compare favourably to available international data. 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.

Electrophysiological and mechanical effects of caffeic acid phenethyl ester, a novel cardioprotective agent with antiarrhythmic activity, in guinea-pig heart.

PubMed

Chang, Gwo-Jyh; Chang, Chi-Jen; Chen, Wei-Jan; Yeh, Yung-Hsin; Lee, Hsiao-Yu

2013-02-28

Caffeic acid phenethyl ester (CAPE) is an active component of propolis that exhibits cardioprotective and antiarrhythmic effects. The detailed mechanisms underlying these effects, however, are not entirely understood. The aim of this study was to elucidate the electromechanical effects of CAPE in guinea-pig cardiac preparations. Intracardiac electrograms, left ventricular (LV) pressure, and the anti-arrhythmic efficacy were determined using isolated hearts. Action potentials of papillary muscles were assessed with microelectrodes, Ca(2+) transients were measured by fluorescence, and ion fluxes were measured by patch-clamp techniques. In a perfused heart model, CAPE prolonged the atrio-ventricular conduction interval, the Wenckebach cycle length, and the refractory periods of the AV node and His-Purkinje system, while shortening the QT interval. CAPE reduced the occurrence of reperfusion-induced ventricular fibrillation and decreased LV pressure in isolated hearts. In papillary muscles, CAPE shortened the action potential duration and reduced both the maximum upstroke velocity and contractile force. In fura-2-loaded single ventricular myocytes, CAPE decreased cell shortening and the Ca(2+) transient amplitude. Patch-clamp experiments revealed that CAPE produced a use-dependent decrease in L-type Ca(2+) current (ICa,L) (IC50=1.1 μM) and Na(+) current (INa) (IC50=0.43 μM), caused a negative-shift of the voltage-dependent inactivation and a delay of recovery from inactivation. CAPE decreased the delayed outward K(+) current (IK) slightly, without affecting the inward rectifier K(+) current (IK1). These results suggest that the preferential inhibition of Ca(2+) inward and Na(+) inward currents by CAPE may induce major electromechanical alterations in guinea-pig cardiac preparations, which may underlie its antiarrhythmic action. Copyright © 2013 Elsevier B.V. All rights reserved.

A Network Optimization Solution using SAS/OR Tools for the Department of the Army Branching Problem

DTIC Science & Technology

2010-02-18

OPTMODEL; NETFLOW ;Nodes;Arcs;ROTC; assignments;Basic Branches;Cadet Satisfaction; CLASSIFICATION: Unclassified This paper will demonstrate...implement a solution using the NETFLOW procedure and repeat that network solution using the OPTMODEL procedure. The OPTMODEL implementation will be...96.545599 M 1 AV AV IN EN FA AR 4 96.221521 M 1 IN IN MI EN MP AR 1 Figure 1, Supply: cadet data (5 of 2545) ordered by OMS PROC NETFLOW takes a

Clinical predictors of challenging atrioventricular node ablation procedure for rate control in patients with atrial fibrillation.

PubMed

Polin, Baptiste; Behar, Nathalie; Galand, Vincent; Auffret, Vincent; Behaghel, Albin; Pavin, Dominique; Daubert, Jean-Claude; Mabo, Philippe; Leclercq, Christophe; Martins, Raphael P

2017-10-15

Atrioventricular node (AVN) ablation is usually a simple procedure but may sometimes be challenging. We aimed at identifying pre-procedural clinical predictors of challenging AVN ablation. Patients referred for AVN ablation from 2009 to 2015 were retrospectively included. Baseline clinical data, procedural variables and outcomes of AVN ablation were collected. A "challenging procedure" was defined 1) total radiofrequency delivery to get persistent AVN block≥400s, 2) need for left-sided arterial approach or 3) failure to obtain AVN ablation. 200 patients were included (71±10years). A total of 37 (18.5%) patients had "challenging" procedures (including 9 failures, 4.5%), while 163 (81.5%) had "non-challenging" ablations. In multivariable analysis, male sex (Odds ratio (OR)=4.66, 95% confidence interval (CI): 1.74-12.46), body mass index (BMI, OR=1.08 per 1kg/m 2 , 95%CI 1.01-1.16), operator experience (OR=0.40, 95%CI 0.17-0.94), and moderate-to-severe tricuspid regurgitation (TR, OR=3.65, 95%CI 1.63-8.15) were significant predictors of "challenging" ablations. The proportion as a function of number of predictors was analyzed (from 0 to 4, including male sex, operator inexperience, a BMI>23.5kg/m 2 and moderate-to-severe TR). There was a gradual increase in the risk of "challenging" procedure with the number of predictors by patient (No predictor: 0%; 1 predictor: 6.3%; 2 predictors: 16.5%; 3 predictors: 32.5%; 4 predictors: 77.8%). Operator experience, male sex, higher BMI and the degree of TR were independent predictors of "challenging" AVN ablation procedure. The risk increases with the number of predictors by patient. Copyright © 2017. Published by Elsevier B.V.

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.

Altered profile of mRNA expression in atrioventricular node of streptozotocin-induced diabetic rats

PubMed Central

Howarth, Frank Christopher; Parekh, Khatija; Jayaprakash, Petrilla; Inbaraj, Edward Samuel; Oz, Murat; Dobrzynski, Halina; Adrian, Thomas Edward

2017-01-01

Prolonged action potential duration, reduced action potential firing rate, upstroke velocity and rate of diastolic depolarization have been demonstrated in atrioventricular node (AVN) cells from streptozotocin (STZ)-induced diabetic rats. To further clarify the molecular basis of these electrical disturbances, the mRNA profiles encoding a variety of proteins associated with the generation and conduction of electrical activity in the AVN, were evaluated in the STZ-induced diabetic rat heart. Expression of mRNA was measured in AVN biopsies using reverse transcription-quantitative polymerase chain reaction techniques. Notable differences in mRNA expression included upregulation of genes encoding membrane and intracellular Ca2+ transport, including solute carrier family 8 member A1, transient receptor potential channel 1, ryanodine receptor 2/3, hyperpolarization-activated cyclic-nucleotide 2 and 3, calcium channel voltage-dependent, β2 subunit and sodium channels 3a, 4a, 7a and 3b. In addition to this, potassium channels potassium voltage-gated channel subfamily A member 4, potassium channel calcium activated intermediate/small conductance subfamily N α member 2, potassium voltage-gated channel subfamily J members 3, 5, and 11, potassium channel subfamily K members 1, 2, 3 and natriuretic peptide B (BNP) were upregulated in AVN of STZ heart, compared with controls. Alterations in gene expression were associated with upregulation of various proteins including the inwardly rectifying, potassium channel Kir3.4, NCX1 and BNP. The present study demonstrated notable differences in the profile of mRNA encoding proteins associated with the generation, conduction and regulation of electrical signals in the AVN of the STZ-induced diabetic rat heart. These data will provide a basis for a substantial range of future studies to investigate whether variations in mRNA translate into alterations in electrophysiological function. PMID:28731153

Safety and feasibility of leadless pacemaker in patients undergoing atrioventricular node ablation for atrial fibrillation.

PubMed

Yarlagadda, Bharath; Turagam, Mohit K; Dar, Tawseef; Jangam, Pragna; Veerapaneni, Vaishnavi; Atkins, Donita; Bommana, Sudharani; Friedman, Paul; Deshmukh, Abhishek J; Doshi, Rahul; Reddy, Vivek Y; Dukkipati, Srinivas R; Natale, Andrea; Lakkireddy, Dhanunjaya

2018-03-01

Atrioventricular node (AVN) ablation and permanent pacing is an established strategy for rate control in the management of symptomatic atrial fibrillation (AF). Leadless pacemakers (LPs) can overcome some of the short-term and long-term limitations of conventional transvenous pacemakers (CTPs). The purpose of this study was to compare the feasibility and safety of LP with those of single-chamber CTP in patients with AF undergoing AVN ablation. We conducted a multicenter observational study of patients undergoing AVN ablation and pacemaker implantation (LP vs single-chamber CTP) between February 2014 and November 2016. The primary efficacy end points were acceptable sensing (R wave ≥5.0 mV) and pacing thresholds (≤2.0 V at 0.4 ms) at follow-up. Safety end points included device-related major and minor (early ≤1 month, late >1 month) adverse events. A total of 127 patients with LP (n = 60) and CTP (n = 67) were studied. The median follow-up was 12 months (interquartile range 12-18 months). Ninety-five percent of the LP group and 97% of the CTP group met the primary efficacy end point at follow-up (57 of 60 vs 65 of 67; P = .66). There was 1 major adverse event (loss of pacing and sensing) in the LP group and 2 (lead dislodgement) in the CTP group (1 of 60 vs 2 of 67; P = 1.00). There were 6 minor adverse events (5 early and 1 late) in the LP group and 3 (early) in the CTP group (6 of 60 vs 3 of 67; P = .30). Our results demonstrate the feasibility and safety of LP compared with CTP in patients undergoing AVN ablation for AF. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Dual-chamber pacemakers for treating symptomatic bradycardia due to sick sinus syndrome without atrioventricular block: a systematic review and economic evaluation.

PubMed

Edwards, Steven J; Karner, Charlotta; Trevor, Nicola; Wakefield, Victoria; Salih, Fatima

2015-08-01

Bradycardia [resting heart rate below 60 beats per minute (b.p.m.)] can be caused by conditions affecting the natural pacemakers of the heart, such as sick sinus syndrome (SSS) and atrioventricular (AV) blocks. People suffering from bradycardia may present with palpitations, exercise intolerance and fainting. The only effective treatment for patients suffering from symptomatic bradycardia is implantation of a permanent pacemaker. To appraise the clinical effectiveness and cost-effectiveness of dual-chamber pacemakers compared with single-chamber atrial pacemakers for treating symptomatic bradycardia in people with SSS and no evidence of AV block. All databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluations Database) were searched from inception to June 2014. A systematic review of the clinical and economic literature was carried out in accordance with the general principles published by the Centre for Reviews and Dissemination. Randomised controlled trials (RCTs) evaluating dual-chamber and single-chamber atrial pacemakers and economic evaluations were included. Pairwise meta-analysis was carried out. A de novo economic model was developed. Of 493 references, six RCTs were included in the review. The results were predominantly influenced by the largest trial DANPACE. Dual-chamber pacing was associated with a statistically significant reduction in reoperation [odds ratio (OR) 0.48, 95% confidence interval (CI) 0.36 to 0.63] compared with single-chamber atrial pacing. The difference is primarily because of the development of AV block requiring upgrade to a dual-chamber device. The risk of paroxysmal atrial fibrillation was also reduced with dual-chamber pacing compared with single-chamber atrial pacing (OR 0.75, 95% CI 0.59 to 0.96). No statistically significant difference was found between the pacing modes for mortality, heart failure, stroke, chronic atrial fibrillation or quality of life. However, the risk of developing heart failure may vary with age and device. The de novo economic model shows that dual-chamber pacemakers are more expensive and more effective than single-chamber atrial devices, resulting in a base-case incremental cost-effectiveness ratio (ICER) of £6506. The ICER remains below £20,000 in probabilistic sensitivity analysis, structural sensitivity analysis and most scenario analyses and one-way sensitivity analyses. The risk of heart failure may have an impact on the decision to use dual-chamber or single-chamber atrial pacemakers. Results from an analysis based on age (> 75 years or ≤ 75 years) and risk of heart failure indicate that dual-chamber pacemakers dominate single-chamber atrial pacemakers (i.e. are less expensive and more effective) in older patients, whereas dual-chamber pacemakers are dominated by (i.e. more expensive and less effective) single-chamber atrial pacemakers in younger patients. However, these results are based on a subgroup analysis and should be treated with caution. In patients with SSS without evidence of impaired AV conduction, dual-chamber pacemakers appear to be cost-effective compared with single-chamber atrial pacemakers. The risk of developing a complete AV block and the lack of tools to identify patients at high risk of developing the condition argue for the implantation of a dual-chamber pacemaker programmed to minimise unnecessary ventricular pacing. However, considerations have to be made around the risk of developing heart failure, which may depend on age and device. This study is registered as PROSPERO CRD42013006708. The National Institute for Health Research Health Technology Assessment programme.

[Fetal atrioventricular septal defect associated with Patau and Edwards syndromes, as well as trisomy 22].

PubMed

Cesko, I; Hajdú, J; Marton, T; Tóth-Pál, E; Papp, C; Papp, Z

1998-05-03

The atrioventricular septal defect is usually associated with trisomy 21 and it may be observed in the heterotaxia syndromes. Atrioventricular septal defect may be associated with 8p deletion. There are reported cases of familial atrioventricular septal defect. Atrioventicular septal defect is rarely associated with other chromosomal abnormalities. We are reporting three unusual cases of atrioventricular septal defect that were associated with trisomy 13, 18 and 22. This association may be due to effect of genetic loci on the 13, 18 and 22 chromosome which could play the role in the development and fusion of endocardial cushion and atrioventricular septal defect.

Congestive Heart Failure Leads to Prolongation of the PR Interval and Atrioventricular Junction Enlargement and Ion Channel Remodelling in the Rabbit

PubMed Central

Nikolaidou, Theodora; Cai, Xue J.; Stephenson, Robert S.; Yanni, Joseph; Lowe, Tristan; Atkinson, Andrew J.; Jones, Caroline B.; Sardar, Rida; Corno, Antonio F.; Dobrzynski, Halina; Withers, Philip J.; Jarvis, Jonathan C.; Hart, George; Boyett, Mark R.

2015-01-01

Heart failure is a major killer worldwide. Atrioventricular conduction block is common in heart failure; it is associated with worse outcomes and can lead to syncope and bradycardic death. We examine the effect of heart failure on anatomical and ion channel remodelling in the rabbit atrioventricular junction (AVJ). Heart failure was induced in New Zealand rabbits by disruption of the aortic valve and banding of the abdominal aorta resulting in volume and pressure overload. Laser micro-dissection and real-time polymerase chain reaction (RT-PCR) were employed to investigate the effects of heart failure on ion channel remodelling in four regions of the rabbit AVJ and in septal tissues. Investigation of the AVJ anatomy was performed using micro-computed tomography (micro-CT). Heart failure animals developed first degree heart block. Heart failure caused ventricular myocardial volume increase with a 35% elongation of the AVJ. There was downregulation of HCN1 and Cx43 mRNA transcripts across all regions and downregulation of Cav1.3 in the transitional tissue. Cx40 mRNA was significantly downregulated in the atrial septum and AVJ tissues but not in the ventricular septum. mRNA abundance for ANP, CLCN2 and Navβ1 was increased with heart failure; Nav1.1 was increased in the inferior nodal extension/compact node area. Heart failure in the rabbit leads to prolongation of the PR interval and this is accompanied by downregulation of HCN1, Cav1.3, Cx40 and Cx43 mRNAs and anatomical enlargement of the entire heart and AVJ. PMID:26509807

An approach to ablate and pace:AV junction ablation and pacemaker implantation performed concurrently from the same venous access site.

PubMed

Issa, Ziad F

2007-09-01

Atrioventricular junction (AVJ) ablation combined with permanent pacemaker implantation (the "ablate and pace" approach) remains an acceptable alternative treatment strategy for symptomatic, drug-refractory atrial fibrillation (AF) with rapid ventricular response. This case series describes the feasibility and safety of catheter ablation of the AVJ via a superior vena caval approach performed during concurrent dual-chamber pacemaker implantation. A total of 17 consecutive patients with symptomatic, drug-refractory, paroxysmal AF underwent combined AVJ ablation and dual-chamber pacemaker implantation procedure using a left axillary venous approach. Two separate introducer sheaths were placed into the axillary vein. The first sheath was used for implantation of the pacemaker ventricular lead, which was then connected to the pulse generator. Subsequently, a standard ablation catheter was introduced through the second axillary venous sheath and used for radiofrequency (RF) ablation of the AVJ. After successful ablation, the catheter was withdrawn and the pacemaker atrial lead was advanced through that same sheath and implanted in the right atrium. Catheter ablation of the AVJ was successfully achieved in all patients. The median number of RF applications required to achieve complete AV block was three (range 1-10). In one patient, AV conduction recovered within the first hour after completion of the procedure, and AVJ ablation was then performed using the conventional femoral venous approach. There were no procedural complications. Catheter ablation of the AVJ can be performed successfully and safely via a superior vena caval approach in patients undergoing concurrent dual-chamber pacemaker implantation.

Survival after extreme left atrial hypertension and pulmonary hemorrhage in an infant supported with extracorporeal membrane oxygenation for refractory atrial flutter.

PubMed

Cisco, Michael J; Asija, Ritu; Dubin, Anne M; Perry, Stanton B; Hanley, Frank L; Roth, Stephen J

2011-05-01

We report here the survival of an infant who developed extreme left atrial hypertension and severe pulmonary hemorrhage while supported with extracorporeal membrane oxygenation for refractory atrial flutter. The patient recovered after decompression of the left heart and catheter ablation of the atrioventricular node. Lucile Packard Children's Hospital (Stanford, CA). Chart review. Recovery of lung function is possible despite systemic-level left atrial pressure resulting in pulmonary hemorrhage and complete solidification of lung parenchyma on gross inspection. Resolution of pulmonary hemorrhage despite anticoagulation while on extracorporeal membrane oxygenation can occur after relief of left atrial hypertension.

Mef2c Regulates Transcription of the Extracellular Matrix Protein Cartilage Link Protein 1 in the Developing Murine Heart

PubMed Central

Phelps, Aimee L.; Ghatnekar, Angela V.; Barth, Jeremy L.; Norris, Russell A.; Wessels, Andy

2013-01-01

Cartilage Link Protein 1 (Crtl1) is an extracellular matrix (ECM) protein that stabilizes the interaction between hyaluronan and versican and is expressed in endocardial and endocardially-derived cells in the developing heart, including cells in the atrioventricular (AV) and outflow tract (OFT) cushions. Previous investigations into the transcriptional regulation of the Crtl1 gene have shown that Sox9 regulates Crtl1 expression in both cartilage and the AV valves. The cardiac transcription factor Mef2c is involved in the regulation of gene expression in cardiac and skeletal muscle cell lineages. In this study we have investigated the potential role of Mef2c in the regulation of ECM production in the endocardial and mesenchymal cell lineages of the developing heart. We demonstrate that the Crtl1 5′ flanking region contains two highly conserved Mef2 binding sites and that Mef2c is able to bind to these sites in vivo during cardiovascular development. Additionally, we show that Crtl1 transcription is dependent on Mef2c expression in fetal mitral valve interstitial cells (VICs). Combined, these findings highlight a new role for Mef2c in cardiac development and the regulation of cardiac extracellular matrix protein expression. PMID:23468913

Calculation of pressure drop in the developmental stages of the medaka fish heart and microvasculature

NASA Astrophysics Data System (ADS)

Chakraborty, Sreyashi; Vlachos, Pavlos

2016-11-01

Peristaltic contraction of the developing medaka fish heart produces temporally and spatially varying pressure drop across the atrioventricular (AV) canal. Blood flowing through the tail vessels experience a slug flow across the developmental stages. We have performed a series of live imaging experiments over 14 days post fertilization (dpf) of the medaka fish egg and cross-correlated the red blood cell (RBC) pattern intensities to obtain the two-dimensional velocity fields. Subsequently we have calculated the pressure field by integrating the pressure gradient in the momentum equation. Our calculations show that the pressure drop across the AV canal increases from 0.8mm Hg during 3dpf to 2.8 mm Hg during 14dpf. We have calculated the time-varying wall shear stress for the blood vessels by assuming a spatially constant velocity magnitude in each vessel. The calculated wall shear stress matches the wall shear stress sensed by human endothelial cells (10-12 dyne/sq. cm). The pressure drop per unit length of the vessel is obtained by doing a control volume analysis of flow in the caudal arteries and veins. The current results can be extended to investigate the effect of the fluid dynamic parameters on the vascular and cardiac morphogenesis.

Risk of cardiac rhythm disturbances and aortic regurgitation in different spondyloarthritis subtypes in comparison with general population: a register-based study from Sweden.

PubMed

Bengtsson, Karin; Forsblad-d'Elia, Helena; Lie, Elisabeth; Klingberg, Eva; Dehlin, Mats; Exarchou, Sofia; Lindström, Ulf; Askling, Johan; Jacobsson, Lennart T H

2018-04-01

To describe the incidence of atrioventricular (AV) block II-III, atrial fibrillation (AF), pacemaker implantation (PM) and aortic regurgitation in patients with ankylosing spondylitis (AS), undifferentiated spondyloarthritis (uSpA) and psoriatic arthritis (PsA) compared with the general population (GP) and with each other. A prospective nationwide study with cohorts of patients with AS (n=6448), PsA (n=16 063) and uSpA (n=5190) and a GP (n=2 66 435) cohort, identified in 2001-2009 in the Swedish National Patient and Population registers. Follow-up began on 1 January 2006 and ended at event, death, emigration or 31 December 2012. Age-standardised and sex-standardised incidence rates and hazard ratios (HRs) were calculated. The highest incidence rates were noted for AF (5.5-7.4 events per 1000 person-years), followed by PM (1.0-2.0 events per 1000 person-years). HRs for AV block, AF, PM and aortic regurgitation were significantly increased in AS (HRs 2.3, 1.3, 2.1 and 1.9), uSpA (HRs 2.9, 1.3, 1.9 and 2.0) and PsA (HRs 1.5, 1.5, 1.6 and 1.8) compared with the GP cohort. The highest HRs were seen for AV block in male uSpA (HR 4.2) and AS (HR 2.5) compared with GP. Compared with PsA, significantly increased HRs were noted for PM (HR 1.5) in AS and for AV block (HR 1.8) in uSpA. Patients with SpA are at increased risk of aortic regurgitation, cardiac rhythm disturbances and, as a probable consequence, also PM. Particularly for AF, the most common arrhythmia, increased caution is warranted, whereas AV block should be looked for especially in men with AS or uSpA. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Comparison of cryoablation with 3D mapping versus conventional mapping for the treatment of atrioventricular re-entrant tachycardia and right-sided paraseptal accessory pathways.

PubMed

Russo, Mario S; Drago, Fabrizio; Silvetti, Massimo S; Righi, Daniela; Di Mambro, Corrado; Placidi, Silvia; Prosperi, Monica; Ciani, Michele; Naso Onofrio, Maria T; Cannatà, Vittorio

2016-06-01

Aim Transcatheter cryoablation is a well-established technique for the treatment of atrioventricular nodal re-entry tachycardia and atrioventricular re-entry tachycardia in children. Fluoroscopy or three-dimensional mapping systems can be used to perform the ablation procedure. The aim of this study was to compare the success rate of cryoablation procedures for the treatment of right septal accessory pathways and atrioventricular nodal re-entry circuits in children using conventional or three-dimensional mapping and to evaluate whether three-dimensional mapping was associated with reduced patient radiation dose compared with traditional mapping. In 2013, 81 children underwent transcatheter cryoablation at our institution, using conventional mapping in 41 children - 32 atrioventricular nodal re-entry tachycardia and nine atrioventricular re-entry tachycardia - and three-dimensional mapping in 40 children - 24 atrioventricular nodal re-entry tachycardia and 16 atrioventricular re-entry tachycardia. Using conventional mapping, the overall success rate was 78.1 and 66.7% in patients with atrioventricular nodal re-entry tachycardia or atrioventricular re-entry tachycardia, respectively. Using three-dimensional mapping, the overall success rate was 91.6 and 75%, respectively (p=ns). The use of three-dimensional mapping was associated with a reduction in cumulative air kerma and cumulative air kerma-area product of 76.4 and 67.3%, respectively (p<0.05). The use of three-dimensional mapping compared with the conventional fluoroscopy-guided method for cryoablation of right septal accessory pathways and atrioventricular nodal re-entry circuits in children was associated with a significant reduction in patient radiation dose without an increase in success rate.

The role of the Na+/Ca2+ exchanger, INa and ICaL in the genesis of dofetilide-induced torsades de pointes in isolated, AV-blocked rabbit hearts

PubMed Central

Farkas, Attila S; Makra, Péter; Csík, Norbert; Orosz, Szabolcs; Shattock, Michael J; Fülöp, Ferenc; Forster, Tamás; Csanády, Miklós; Papp, Julius Gy; Varró, András; Farkas, András

2009-01-01

Background and purpose: The Na+/Ca2+ exchanger (NCX) may contribute to triggered activity and transmural dispersion of repolarization, which are substrates of torsades de pointes (TdP) type arrhythmias. This study examined the effects of selective inhibition of the NCX by SEA0400 on the occurrence of dofetilide-induced TdP. Experimental approach: Effects of SEA0400 (1 µmol·L−1) on dofetilide-induced TdP was studied in isolated, Langendorff-perfused, atrioventricular (AV)-blocked rabbit hearts. To verify the relevance of the model, lidocaine (30 µmol·L−1) and verapamil (750 nmol·L−1) were also tested against dofetilide-induced TdP. Key results: Acute AV block caused a chaotic idioventricular rhythm and strikingly increased beat-to-beat variability of the RR and QT intervals. SEA0400 exaggerated the dofetilide-induced increase in the heart rate-corrected QT interval (QTc) and did not reduce the incidence of dofetilide-induced TdP [100% in the SEA0400 + dofetilide group vs. 75% in the dofetilide (100 nmol·L−1) control]. In the second set of experiments, verapamil further increased the dofetilide-induced QTc prolongation and neither verapamil nor lidocaine reduced the dofetilide-induced increase in the beat-to-beat variability of the QT interval. However, lidocaine decreased and verapamil prevented the development of dofetilide-induced TdP as compared with the dofetilide control (TdP incidence: 13%, 0% and 88% respectively). Conclusions and implications: Na+/Ca2+ exchanger does not contribute to dofetilide-induced TdP, whereas Na+ and Ca2+ channel activity is involved in TdP genesis in isolated, AV-blocked rabbit hearts. Neither QTc prolongation nor an increase in the beat-to-beat variability of the QT interval is a sufficient prerequisite of TdP genesis in rabbit hearts. PMID:19222480

Right bundle branch block without overt heart disease predicts higher risk of pacemaker implantation: the study of atomic-bomb survivors.

PubMed

Kusumoto, Saburo; Kawano, Hiroaki; Makita, Naomasa; Ichimaru, Shinichiro; Kaku, Takashi; Haruta, Daisuke; Hida, Ayumi; Sera, Nobuko; Imaizumi, Misa; Nakashima, Eiji; Maemura, Koji; Akahoshi, Masazumi

2014-06-01

We investigated the clinical course of complete right bundle branch block (RBBB) or RBBB with axis deviation (AD) in terms of subsequent pacemaker implantation for high-degree atrioventricular (AV) block or sick sinus syndrome (SSS). Among the 16,170 atomic-bomb survivors in our biennial health examination between July 1967 and December 2010, we detected 520 newly-acquired RBBB subjects with no organic heart disease, and selected 1038 age- (at RBBB diagnosis) and sex-matched subjects without RBBB to serve as comparison subjects. Multivariate Cox regression analysis was used to estimate the hazard ratios (HRs) for the risk of pacemaker implantation due to all causes, AV block or SSS between RBBB and comparison subjects and between RBBB subjects with and without AD. The risk of pacemaker implantation for RBBB was 4.79 (95% confidence interval [CI] 1.89-12.58; P=0.001), 3.77 (95% CI, 1.09-13.07; P=0.036), and 6.28 (95% CI, 1.24-31.73, P=0.026) when implantation was for all causes, AV block and SSS, respectively. RBBB subjects with AD had a higher risk for all-cause pacemaker implantation than subjects without AD (HR, 3.03; 95% CI, 1.00-9.13, P=0.049). RBBB subjects with AD were younger than subjects without AD at the time of RBBB diagnosis (59.4±7.6 vs 74.4±3.1 years old, P=0.019), and their progression from diagnosis to pacemaker implantation took longer (15.1±6.6 vs 6.4±3.0 years, P=0.032). RBBB, especially with AD, progresses to AV block and SSS that requires pacemaker implantation; the mechanisms by which the conduction defect progresses differ among patients with and without AD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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

PubMed

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

2015-01-01

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

Reversible chronic acquired complete atrioventricular block.

PubMed

Rakovec, P; Milcinski, G; Voga, G; Korsic, L

1982-01-01

The return of atrioventricular conduction is reported in a case after nearly four years of complete acquired heart block. After recovery from atrioventricular block, right bundle branch block persisted, but P-R interval and H-V interval were normal. Three months later a relapse of second degree infranodal atrioventricular block was noted. A short review of similar cases from the literature is given.

[Reversible first-degree atrioventricular block due to hyperthyroidism].

PubMed

Çelebi, Aksüyek Savaş; Amasyalı, Basri

2017-04-01

Hyperthyroidism often causes tachyarrhythmia. Reversible atrioventricular block caused by hyperthyroidism is rare occurrence. Presently described is a case of atrioventricular block due to hyperthyroidism and recovery after antithyroid treatment.

An automatic graph-based approach for artery/vein classification in retinal images.

PubMed

Dashtbozorg, Behdad; Mendonça, Ana Maria; Campilho, Aurélio

2014-03-01

The classification of retinal vessels into artery/vein (A/V) is an important phase for automating the detection of vascular changes, and for the calculation of characteristic signs associated with several systemic diseases such as diabetes, hypertension, and other cardiovascular conditions. This paper presents an automatic approach for A/V classification based on the analysis of a graph extracted from the retinal vasculature. The proposed method classifies the entire vascular tree deciding on the type of each intersection point (graph nodes) and assigning one of two labels to each vessel segment (graph links). Final classification of a vessel segment as A/V is performed through the combination of the graph-based labeling results with a set of intensity features. The results of this proposed method are compared with manual labeling for three public databases. Accuracy values of 88.3%, 87.4%, and 89.8% are obtained for the images of the INSPIRE-AVR, DRIVE, and VICAVR databases, respectively. These results demonstrate that our method outperforms recent approaches for A/V classification.

Electrophysiological markers predicting impeding AV-block during ablation of atrioventricular nodal reentry tachycardia.

PubMed

Fragakis, Nikolaos; Krexi, Lydia; Kyriakou, Panagiota; Sotiriadou, Melani; Lazaridis, Charalambos; Karamanolis, Athanasios; Dalampyras, Panagiotis; Tsakiroglou, Stelios; Skeberis, Vassilios; Tsalikakis, Dimitrios; Vassilikos, Vassilios

2018-01-01

Radiofrequency (RF) ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is occasionally complicated with atrioventricular block (AVB) often predicted by junctional beats (JB) with loss of ventriculo-atrial (VA) conduction. We analyzed retrospectively 153 patients undergoing ablation of SP for typical AVNRT. Patients were divided into two age groups: 127 ≤ 70 years and 26 > 70 years. We analyzed the interval between the atrial electrogram in the His-bundle position and the distal ablation catheter [A(H)-A(RFd)] and between the distal ablation catheter and the proximal coronary sinus catheter [A(RFd)-A(CS)] before RF applications with and without JB. We evaluated if these intervals can be used as predictors of JB incidence and also of JB with loss of VA conduction. We also assessed if age influences the risk of loss of VA conduction. The A(H)-A(RFd) and A(RFd)-A(CS) intervals were significantly shorter in RF applications causing JB than those without JB (33 ± 11 ms vs 39 ± 9 ms, P < 0.001, 14 ± 9 ms vs 20 ± 7 ms, P < 0.001, respectively). The A(H)-A(RFd) and A(RFd)-A(CS) intervals were also significantly shorter in RFs causing JB with VA block than those with VA conduction (29 ± 11 ms vs 35 ± 11 ms, P < 0.001, 8 ± 8 ms vs 17 ± 8 ms, P < 0.001, respectively). Patients > 70 years had shorter intervals (36 ± 11 ms vs 29 ± 8 ms, P  =  0.012, 17 ± 8 ms vs 13 ± 7 ms, P  =  0.027, respectively), while VA block was more common in this age group. The A(H)-A(RFd) and A(RFd)-A(CS) intervals can be used as markers for predicting JB occurrence as well as impending AVB. JB with loss of VA conduction occur more often in older patients possibly due to a higher position of SP. © 2017 Wiley Periodicals, Inc.

Atrioventricular Canal Defect

MedlinePlus

... birth (congenital). The condition is often associated with Down syndrome. Atrioventricular canal defect allows extra blood to flow ... baby's heart is developing. Some factors, such as Down syndrome, might increase the risk of atrioventricular canal defect. ...

Unbalanced atrioventricular septal defect: definition and decision making.

PubMed

Overman, David M; Baffa, Jeanne M; Cohen, Meryl S; Mertens, Luc; Gremmels, David B; Jegatheeswaram, Anusha; McCrindle, Brian W; Blackstone, Eugene H; Morell, Victor O; Caldarone, Christopher; Williams, William G; Pizarro, Christian

2010-04-01

Unbalanced atrioventricular septal defect is an uncommon lesion with widely varying anatomic manifestations. When unbalance is severe, diagnosis and treatment is straightforward, directed toward single-ventricle palliation. Milder forms, however, pose a challenge to current diagnostic and therapeutic approaches. The transition from anatomies that are capable of sustaining biventricular physiology to those that cannot is obscure, resulting in uneven application of surgical strategy and excess mortality. Imprecise assessments of ventricular competence have dominated clinical decision making in this regard. Malalignment of the atrioventricular junction and its attendant derangement of inflow physiology is a critical factor in determining the feasibility of biventricular repair in the setting of unbalanced atrioventricular septal defect. The atrioventricular valve index accurately identifies unbalanced atrioventricular septal defect and also brings into focus a zone of transition from anatomies that can support a biventricular end state and those that cannot.

Correlation between the sudden jump-like increases of the atrio-Hisian interval induced during burst atrial pacing and during programmed atrial stimulation in patients with atrioventricular nodal reentrant tachycardia.

PubMed

Bayraktarova, Iskra H; Stoyanov, Milko K; Kunev, Boyan T; Shalganov, Tchavdar N

To study the correlation between the sudden prolongations of the atrio-Hisian (AH) interval with ≥50 ms during burst and programmed atrial stimulation, and to define whether the AH jump during burst atrial pacing is a reliable diagnostic criterion for dual AV nodal physiology. Retrospective data on 304 patients with preliminary ECG diagnosis of AV nodal reentrant tachycardia (AVNRT), confirmed during electrophysiological study, was analyzed for the presence of AH jump during burst and programmed atrial stimulation, and for correlation between the pacing modes for inducing the jump. Wilcoxon signed-ranks test and Spearman's bivariate correlation coefficient were applied, significant was P-value <0.05. The population was aged 48.5 ± 15.7 (12-85) years; males were 38.5%. AH jump occurred during burst atrial pacing in 81% of the patients, and during programmed stimulation - in 78%, P = 0.366. In 63.2% AH jump was induced by both pacing modes; in 17.8% - only by burst pacing; in 14.8% - only by programmed pacing; in 4.2% there was no inducible jump. There was negative correlation between both pacing modes, ρ = -0.204, Р<0.001. Burst and programmed atrial stimulation separately prove the presence of dual AV nodal physiology in 81 and 78% of the patients with AVNRT, respectively. There is negative correlation between the two pacing modes, allowing the combination of the two methods to prove diagnostic in 95.8% of the patients. Copyright © 2017 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.

The magnetic navigation system allows safety and high efficacy for ablation of arrhythmias.

PubMed

Bauernfeind, Tamas; Akca, Ferdi; Schwagten, Bruno; de Groot, Natasja; Van Belle, Yves; Valk, Suzanne; Ujvari, Barbara; Jordaens, Luc; Szili-Torok, Tamas

2011-07-01

We aimed to evaluate the safety and long-term efficacy of the magnetic navigation system (MNS) in a large number of patients. The MNS has the potential for improving safety and efficacy based on atraumatic catheter design and superior navigation capabilities. In this study, 610 consecutive patients underwent ablation. Patients were divided into two age- and sex-matched groups. Ablations were performed either using MNS (group MNS, 292) or conventional manual ablation [group manual navigation (MAN), 318]. The following parameters were analysed: acute success rate, fluoroscopy time, procedure time, complications [major: pericardial tamponade, permanent atrioventricular (AV) block, major bleeding, and death; minor: minor bleeding and temporary AV block]. Recurrence rate was assessed during follow-up (15±9.5 months). Subgroup analysis was performed for the following groups: atrial fibrillation, isthmus dependent and atypical atrial flutter, atrial tachycardia, AV nodal re-entrant tachycardia, circus movement tachycardia, and ventricular tachycardia (VT). Magnetic navigation system was associated with less major complications (0.34 vs. 3.2%, P=0.01). The total numbers of complications were lower in group MNS (4.5 vs. 10%, P=0.005). Magnetic navigation system was equally effective as MAN in acute success rate for overall groups (92 vs. 94%, P=ns). Magnetic navigation system was more successful for VTs (93 vs. 72%, P<0.05). Less fluoroscopy was used in group MNS (30±20 vs. 35±25 min, P<0.01). There were no differences in procedure times and recurrence rates for the overall groups (168±67 vs. 159±75 min, P=ns; 14 vs. 11%, P=ns; respectively). Our data suggest that the use of MNS improves safety without compromising efficiency of ablations. Magnetic navigation system is more effective than manual ablation for VTs.

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

PubMed Central

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

2015-01-01

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

Nonpharmacologic control of postoperative supraventricular arrhythmias using AV nodal fat pad stimulation in a young animal open heart surgical model.

PubMed

Moak, Jeffrey P; Mercader, Marco A; He, Dingchao; Trachiotis, Gregory; Langert, Joshua; Blicharz, Andy; Montaque, Erin; Li, Xiyan; Cheng, Yao I; McCarter, Robert; Bornzin, Gene A; Martin, Gerard R; Jonas, Richard A

2013-06-01

Supraventricular arrhythmias (junctional ectopic tachycardia [JET] and atrial tachyarrhythmias) frequently complicate recovery from open heart surgery in children and can be difficult to manage. Medical treatment of JET can result in significant morbidity. Our goal was to develop a nonpharmacological approach using autonomic stimulation of selective fat pad (FP) regions of the heart in a young canine model of open heart surgery to control 2 common postoperative supraventricular arrhythmias. Eight mongrel dogs, varying in age from 5 to 8 months and weighting 22±4 kg, underwent open heart surgery replicating a nontransannular approach to tetralogy of Fallot repair. Neural stimulation of the right inferior FP was used to control the ventricular response to supraventricular arrhythmias. Right inferior FP stimulation decreased baseline AV nodal conduction without altering sinus cycle length. AV node Wenckebach cycle length prolonged from 270±33 to 352±89 ms, P=0.02. Atrial fibrillation occurred in 7 animals, simulating a rapid atrial tachyarrhythmias. FP stimulation slowed the ventricular response rate from 166±58 to 63±29 beats per minute, P<0.001. Postoperative JET occurred in 7 dogs. FP stimulation slowed the ventricular rate during postoperative JET from 148±31 to 106±32 beats per minute, P<0.001, and restored sinus rhythm in 7/7 dogs. Right inferior FP stimulation had a selective effect on the AV node, and slowed the ventricular rate during postoperative JET and atrial tachyarrhythmias in our young canine open heart surgery model. FP stimulation may be a useful new technique for managing children with JET and atrial tachyarrhythmias.

MURC, a Muscle-Restricted Coiled-Coil Protein That Modulates the Rho/ROCK Pathway, Induces Cardiac Dysfunction and Conduction Disturbance▿

PubMed Central

Ogata, Takehiro; Ueyama, Tomomi; Isodono, Koji; Tagawa, Masashi; Takehara, Naofumi; Kawashima, Tsuneaki; Harada, Koichiro; Takahashi, Tomosaburo; Shioi, Tetsuo; Matsubara, Hiroaki; Oh, Hidemasa

2008-01-01

We identified a novel muscle-restricted putative coiled-coil protein, MURC, which is evolutionarily conserved from frog to human. MURC was localized to the cytoplasm with accumulation in the Z-line of the sarcomere in the murine adult heart. MURC mRNA expression in the heart increased during the developmental process from the embryonic stage to adulthood. In response to pressure overload, MURC mRNA expression increased in the hypertrophied heart. Using the yeast two-hybrid system, we identified the serum deprivation response (SDPR) protein, a phosphatidylserine-binding protein, as a MURC-binding protein. MURC induced activation of the RhoA/ROCK pathway, which modulated serum response factor-mediated atrial natriuretic peptide (ANP) expression and myofibrillar organization. SDPR augmented MURC-induced transactivation of the ANP promoter in cardiomyocytes, and RNA interference of SDPR attenuated the action of MURC on the ANP promoter. Transgenic mice expressing cardiac-specific MURC (Tg-MURC) exhibited cardiac contractile dysfunction and atrioventricular (AV) conduction disturbances with atrial chamber enlargement, reduced thickness of the ventricular wall, and interstitial fibrosis. Spontaneous episodes of atrial fibrillation and AV block were observed in Tg-MURC mice. These findings indicate that MURC modulates RhoA signaling and that MURC plays an important role in the development of cardiac dysfunction and conduction disturbance with increased vulnerability to atrial arrhythmias. PMID:18332105

MURC, a muscle-restricted coiled-coil protein that modulates the Rho/ROCK pathway, induces cardiac dysfunction and conduction disturbance.

PubMed

Ogata, Takehiro; Ueyama, Tomomi; Isodono, Koji; Tagawa, Masashi; Takehara, Naofumi; Kawashima, Tsuneaki; Harada, Koichiro; Takahashi, Tomosaburo; Shioi, Tetsuo; Matsubara, Hiroaki; Oh, Hidemasa

2008-05-01

We identified a novel muscle-restricted putative coiled-coil protein, MURC, which is evolutionarily conserved from frog to human. MURC was localized to the cytoplasm with accumulation in the Z-line of the sarcomere in the murine adult heart. MURC mRNA expression in the heart increased during the developmental process from the embryonic stage to adulthood. In response to pressure overload, MURC mRNA expression increased in the hypertrophied heart. Using the yeast two-hybrid system, we identified the serum deprivation response (SDPR) protein, a phosphatidylserine-binding protein, as a MURC-binding protein. MURC induced activation of the RhoA/ROCK pathway, which modulated serum response factor-mediated atrial natriuretic peptide (ANP) expression and myofibrillar organization. SDPR augmented MURC-induced transactivation of the ANP promoter in cardiomyocytes, and RNA interference of SDPR attenuated the action of MURC on the ANP promoter. Transgenic mice expressing cardiac-specific MURC (Tg-MURC) exhibited cardiac contractile dysfunction and atrioventricular (AV) conduction disturbances with atrial chamber enlargement, reduced thickness of the ventricular wall, and interstitial fibrosis. Spontaneous episodes of atrial fibrillation and AV block were observed in Tg-MURC mice. These findings indicate that MURC modulates RhoA signaling and that MURC plays an important role in the development of cardiac dysfunction and conduction disturbance with increased vulnerability to atrial arrhythmias.

[Analysis of pacemaker ECGs].

PubMed

Israel, Carsten W; Ekosso-Ejangue, Lucy; Sheta, Mohamed-Karim

2015-09-01

The key to a successful analysis of a pacemaker electrocardiogram (ECG) is the application of the systematic approach used for any other ECG without a pacemaker: analysis of (1) basic rhythm and rate, (2) QRS axis, (3) PQ, QRS and QT intervals, (4) morphology of P waves, QRS, ST segments and T(U) waves and (5) the presence of arrhythmias. If only the most obvious abnormality of a pacemaker ECG is considered, wrong conclusions can easily be drawn. If a systematic approach is skipped it may be overlooked that e.g. atrial pacing is ineffective, the left ventricle is paced instead of the right ventricle, pacing competes with intrinsic conduction or that the atrioventricular (AV) conduction time is programmed too long. Apart from this analysis, a pacemaker ECG which is not clear should be checked for the presence of arrhythmias (e.g. atrial fibrillation, atrial flutter, junctional escape rhythm and endless loop tachycardia), pacemaker malfunction (e.g. atrial or ventricular undersensing or oversensing, atrial or ventricular loss of capture) and activity of specific pacing algorithms, such as automatic mode switching, rate adaptation, AV delay modifying algorithms, reaction to premature ventricular contractions (PVC), safety window pacing, hysteresis and noise mode. A systematic analysis of the pacemaker ECG almost always allows a probable diagnosis of arrhythmias and malfunctions to be made, which can be confirmed by pacemaker control and can often be corrected at the touch of the right button to the patient's benefit.

Anatomy of Atrioventricular Node Artery and Pattern of Dominancy in Normal Coronary Subject: A Comparison between Individuals with and without Isolated Right Bundle Branch Block

PubMed Central

Kazemisaeid, Ali; Pakbaz, Marziyeh; Yaminisharif, Ahmad; Davoodi, Gholamreza; Lotfi Tokaldany, Masoumeh; Hakki Kazazi, Elham

2012-01-01

Background: Isolated right bundle branch block (RBBB) is a common finding in the general population. The atrioventricular node (AVN) artery contributes to the blood supply of the right bundle branch. Our hypothesis was that the anatomy of the AVN artery and the pattern of dominancy differ between subjects with and without RBBB. Methods: We retrospectively studied the coronary angiography of 92 patients with RBBB and 184 age- and gender-matched controls without RBBB. All the subjects had angiographically proven normal coronary arteries. The dominant circulation and precise origin of the AVN artery were determined in each subject. Obtained data were compared between the two study groups. Results: There was no significant difference between the two groups in terms of dominancy (p value = 0.200). Origination of the AVN artery from the right circulatory system was more common in both groups, but this pattern was more prevalent in the cases than in the controls (p value = 0.021). There was a great variation of the AVN artery origin. In the total study population, the AVN artery was more commonly separated from a non crux origin than from the crux area. The prevalence of the non-crux origination of the AVN artery was significantly higher in the cases than in the controls (p value < 0.001). While the origination of the AVN artery from the right circulatory system was more common in both groups, the prevalence of the right origin of the AVN artery was significantly higher in the cases than in the controls. We observed that the AVN artery most commonly originated from the dominant artery but not necessarily from the crux. Conclusion: The anatomy of the AVN artery but not the pattern of dominancy is somewhat different in subjects with RBBB compared with normal individuals. PMID:23323077

Anatomy of Atrioventricular Node Artery and Pattern of Dominancy in Normal Coronary Subject: A Comparison between Individuals with and without Isolated Right Bundle Branch Block.

PubMed

Kazemisaeid, Ali; Pakbaz, Marziyeh; Yaminisharif, Ahmad; Davoodi, Gholamreza; Lotfi Tokaldany, Masoumeh; Hakki Kazazi, Elham

2012-11-01

Isolated right bundle branch block (RBBB) is a common finding in the general population. The atrioventricular node (AVN) artery contributes to the blood supply of the right bundle branch. Our hypothesis was that the anatomy of the AVN artery and the pattern of dominancy differ between subjects with and without RBBB. We retrospectively studied the coronary angiography of 92 patients with RBBB and 184 age- and gender-matched controls without RBBB. All the subjects had angiographically proven normal coronary arteries. The dominant circulation and precise origin of the AVN artery were determined in each subject. Obtained data were compared between the two study groups. There was no significant difference between the two groups in terms of dominancy (p value = 0.200). Origination of the AVN artery from the right circulatory system was more common in both groups, but this pattern was more prevalent in the cases than in the controls (p value = 0.021). There was a great variation of the AVN artery origin. In the total study population, the AVN artery was more commonly separated from a non crux origin than from the crux area. The prevalence of the non-crux origination of the AVN artery was significantly higher in the cases than in the controls (p value < 0.001). While the origination of the AVN artery from the right circulatory system was more common in both groups, the prevalence of the right origin of the AVN artery was significantly higher in the cases than in the controls. We observed that the AVN artery most commonly originated from the dominant artery but not necessarily from the crux. The anatomy of the AVN artery but not the pattern of dominancy is somewhat different in subjects with RBBB compared with normal individuals.

Permanent pacemaker implantation in octogenarians with unexplained syncope and positive electrophysiologic testing.

PubMed

Giannopoulos, Georgios; Kossyvakis, Charalampos; Panagopoulou, Vasiliki; Tsiachris, Dimitrios; Doudoumis, Konstantinos; Mavri, Maria; Vrachatis, Dimitrios; Letsas, Konstantinos; Efremidis, Michael; Katsivas, Apostolos; Lekakis, John; Deftereos, Spyridon

2017-05-01

Syncope is a common problem in the elderly, and a permanent pacemaker is a therapeutic option when a bradycardic etiology is revealed. However, the benefit of pacing when no association of symptoms to bradycardia has been shown is not clear, especially in the elderly. The aim of this study was to evaluate the effect of pacing on syncope-free mortality in patients aged 80 years or older with unexplained syncope and "positive" invasive electrophysiologic testing (EPT). This was an observational study. A positive EPT for the purposes of this study was defined by at least 1 of the following: a corrected sinus node recovery time of >525 ms, a basic HV interval of >55 ms, detection of infra-Hisian block, or appearance of second-degree atrioventricular block on atrial decremental pacing at a paced cycle length of >400 ms. Among the 2435 screened patients, 228 eligible patients were identified, 145 of whom were implanted with a pacemaker. Kaplan-Meier analysis determined that time to event (syncope or death) was 50.1 months (95% confidence interval 45.4-54.8 months) with a pacemaker vs 37.8 months (95% confidence interval 31.3-44.4 months) without a pacemaker (log-rank test, P = .001). The 4-year time-dependent estimate of the rate of syncope was 12% vs 44% (P < .001) and that of any-cause death was 41% vs 56% (P = .023), respectively. The multivariable odds ratio was 0.25 (95% confidence interval 0.15-0.40) after adjustment for potential confounders. In patients with unexplained syncope and signs of sinus node dysfunction or impaired atrioventricular conduction on invasive EPT, pacemaker implantation was independently associated with longer syncope-free survival. Significant differences were also shown in the individual components of the primary outcome measure (syncope and death from any cause). Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Safety and efficiency of ventricular pacing prevention with an AAI-DDD changeover mode in patients with sinus node disease or atrioventricular block: impact on battery longevity—a sub-study of the ANSWER trial

PubMed Central

Stockburger, Martin; Defaye, Pascal; Boveda, Serge; Stancak, Branislav; Lazarus, Arnaud; Sipötz, Johann; Nardi, Stefano; Rolando, Mara; Moreno, Javier

2016-01-01

Abstract Aims This ANSWER (EvaluAtioN of the SafeR mode in patients With a dual chambER pacemaker indication) sub-study assesses safety and effectiveness of SafeR™ and the impact of ventricular pacing (VP) prevention on anticipated device longevity and replacement rate. Methods and results Patients implanted for atrioventricular block (AVB, n = 310) or sinus node dysfunction (SND, n = 336) were randomly assigned to SafeR (n = 314) or DDD (n = 318) and followed for 36 months. Safety, median VP, estimated device longevity (mean difference, 95% confidence interval [CI]), and anticipated replacement rates were analysed by pacing mode and implant indication. No difference in mortality, syncope, or mode intolerance was observed between randomization groups regardless of the indication. Ventricular pacing on SafeR vs. DDD was 11.5 vs. 93.6% in the overall population (P < 0.001), 89.2 vs. 83.8% in permanent AVB (P = 0.944), 53.5 vs. 98.2% in intermittent AVB (P < 0.001), and 2.2 vs. 84.7% in SND (P < 0.001). Anticipated median device longevity increased on SafeR by 14 [Q1 10; Q3 17] months [10; 17] (P < 0.001) in the overall population, 9 months [−5; 22] (P = 0.193) in permanent AVB, 14 months [8; 19] (P < 0.001) in intermittent AVB, and 14 months [9; 19] (P < 0.001) in SND. In intermittent AVB and SND, prolonged estimated battery longevity translated into the prevention of one anticipated replacement in at least 23% of patients. Conclusion SafeR was effective in reducing VP in intermittent AVB and in SND. No effect was observed in permanent AVB. No safety issue was observed. Ventricular pacing reduction by SafeR translated into relevant estimated prolongation of device longevity and anticipated reduction of required replacements. PMID:26612882

Effect of nifedipine on atrioventricular conduction as compared with verapamil. Intracardiac electrophysiological study.

PubMed Central

Rowland, E; Evans, T; Krikler, D

1979-01-01

Intravenous nifedipine, a powerful calcium antagonist, had no obvious effect on atrioventricular conduction when administered to 11 patients during routine intracardiac electrophysiological studies. Verapamil on the other hand showed potent antiarrhythmic properties, depressing atrioventricular nodal conduction. Nifedipine thus appears safe in patients with angina pectoris who have disorders of atrioventricular nodal conduction, and in those receiving beta-adrenergic blocking drugs. There appear to be differential effects on the slow inward channels of cardiac cells with different 'calcium antagonists'. PMID:486272

Normal Values for Heart Electrophysiology Parameters of Healthy Swine Determined on Electrophysiology Study.

PubMed

Noszczyk-Nowak, Agnieszka; Cepiel, Alicja; Janiszewski, Adrian; Pasławski, Robert; Gajek, Jacek; Pasławska, Urszula; Nicpoń, Józef

2016-01-01

Swine are a well-recognized animal model for human cardiovascular diseases. Despite the widespread use of porcine model in experimental electrophysiology, still no reference values for intracardiac electrical activity and conduction parameters determined during an invasive electrophysiology study (EPS) have been developed in this species thus far. The aim of the study was to develop a set of normal values for intracardiac electrical activity and conduction parameters determined during an invasive EPS of swine. The study included 36 healthy domestic swine (24-40 kg body weight). EPS was performed under a general anesthesia with midazolam, propofol and isoflurane. The reference values for intracardiac electrical activity and conduction parameters were calculated as arithmetic means ± 2 standard deviations. The reference values were determined for AH, HV and PA intervals, interatrial conduction time at its own and imposed rhythm, sinus node recovery time (SNRT), corrected sinus node recovery time (CSNRT), anterograde and retrograde Wenckebach points, atrial, atrioventricular node and ventricular refractory periods. No significant correlations were found between body weight and heart rate of the examined pigs and their electrophysiological parameters. The hereby presented reference values can be helpful in comparing the results of various studies, as well as in more accurately estimating the values of electrophysiological parameters that can be expected in a given experiment.

Complete atrioventricular block in acute coronary syndrome: prevalence, characterisation and implication on outcome.

PubMed

Aguiar Rosa, Silvia; Timóteo, Ana Teresa; Ferreira, Lurdes; Carvalho, Ramiro; Oliveira, Mario; Cunha, Pedro; Viveiros Monteiro, André; Portugal, Guilherme; Almeida Morais, Luis; Daniel, Pedro; Cruz Ferreira, Rui

2018-04-01

The aim was to characterise acute coronary syndrome patients with complete atrioventricular block and to assess the effect on outcome. Patients admitted with acute coronary syndrome were divided according to the presence of complete atrioventricular block: group 1, with complete atrioventricular block; group 2, without complete atrioventricular block. Clinical, electrocardiographic and echocardiographic characteristics and prognosis during one year follow-up were compared between the groups. Among 4799 acute coronary syndrome patients admitted during the study period, 91 (1.9%) presented with complete atrioventricular block. At presentation, group 1 patients presented with lower systolic blood pressure, higher Killip class and incidence of syncope. In group 1, 86.8% presented with ST-segment elevation myocardial infarction (STEMI), and inferior STEMI was verified in 79.1% of patients in group 1 compared with 21.9% in group 2 ( P<0.001). Right ventricular myocardial infarction was more frequent in group 1 (3.3% vs. 0.2%; P<0.001). Among patients who underwent fibrinolysis complete atrioventricular block was observed in 7.3% in contrast to 2.5% in patients submitted to primary percutaneous coronary intervention ( P<0.001). During hospitalisation group 1 had worse outcomes, with a higher incidence of cardiogenic shock (33.0% vs. 4.5%; P<0.001), ventricular arrhythmias (17.6% vs. 3.6%; P<0.001) and the need for invasive mechanical ventilation (25.3% vs. 5.1%; P<0.001). After a propensity score analysis, in a multivariate regression model, complete atrioventricular block was an independent predictor of hospital mortality (odds ratio 3.671; P=0.045). There was no significant difference in mortality at one-year follow-up between the study groups. Complete atrioventricular block conferred a worse outcome during hospitalisation, including a higher incidence of cardiogenic shock, ventricular arrhythmias and death.

Prospective Study of Adenosine on Atrioventricular Nodal Conduction in Pediatric and Young Adult Patients After Heart Transplantation.

PubMed

Flyer, Jonathan N; Zuckerman, Warren A; Richmond, Marc E; Anderson, Brett R; Mendelsberg, Tamar G; McAllister, Jennie M; Liberman, Leonardo; Addonizio, Linda J; Silver, Eric S

2017-06-20

Supraventricular tachycardia is common after heart transplantation. Adenosine, the standard therapy for treating supraventricular tachycardia in children and adults without transplantation, is relatively contraindicated after transplantation because of a presumed risk of prolonged atrioventricular block in denervated hearts. This study tested whether adenosine caused prolonged asystole after transplantation and if it was effective in blocking atrioventricular nodal conduction in these patients. This was a single-center prospective clinical study including healthy heart transplant recipients 6 months to 25 years of age presenting for routine cardiac catheterization during 2015 to 2016. After catheterization, a transvenous pacing catheter was placed and adenosine was given following a dose-escalation protocol until atrioventricular block was achieved. The incidence of clinically significant asystole (≥12 seconds after adenosine) was quantified. The effects of patient characteristics on adenosine dose required to produce atrioventricular block and duration of effect were also measured. Eighty patients completed adenosine testing. No patient (0%; 95% confidence interval, 0-3) required rescue ventricular pacing. Atrioventricular block was observed in 77 patients (96%; 95% confidence interval, 89-99). The median longest atrioventricular block was 1.9 seconds (interquartile range, 1.4-3.2 seconds), with a mean duration of adenosine effect of 4.3±2.0 seconds. No patient characteristic significantly predicted the adenosine dose to produce atrioventricular block or duration of effect. Results were similar across patient weight categories. Adenosine induces atrioventricular block in healthy pediatric and young adult heart transplant recipients with minimal risk when low initial doses are used (25 μg/kg; 1.5 mg if ≥60 kg) and therapy is gradually escalated. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02462941. © 2017 American Heart Association, Inc.

Ivabradine vs metoprolol in patients with acute inferior wall myocardial infarction-"Expanding arena for ivabradine".

PubMed

Priti, Kumari; Ranwa, Bhanwar L; Gokhroo, Rajendra K; Kishore, Kamal; Bisht, Devendra Singh; Gupta, Sajal

2017-08-01

Atrioventricular (AV) blocks are of concern with the use of beta blockers in inferior wall myocardial infarction (MI). Ivabradine lowers heart rate with a lesser risk of AV blocks. To compare ivabradine with metoprolol in acute inferior wall MI in terms of feasibility, tolerability, and efficacy. It was a prospective double-blind single-center randomized controlled study. Of 1032 patients with acute inferior wall MI, 468 eligible patients were randomized in 1:1 manner to ivabradine (group A) and metoprolol (group B). Intention to treat analysis of 426 patients (group A-232 and group B-232) was performed. The primary endpoint was 30-day incidence of major adverse cardiovascular events including death, reinfarction, complete heart block (CHB), and heart failure. Secondary endpoints included 30 days incidence of recurrent angina, readmission, first- or second-degree AV block, and tachyarrhythmias. Both the drugs decreased the mean heart rate to 62.22±2.95 (group A) vs 62.53±3.59 (group B) beats per minute (P=0.33). Ejection fraction improved in both the groups (5.15±1.93% in group A vs 5.52±2.18% in group B, P=0.065). The two groups did not differ significantly in their primary endpoints in terms of death (group A=1.72% vs group B=1.72%, OR=1.00, 95% CI=0.25-4.05, P=1.00), reinfarction (group A=0.86% vs group B=0.86%, OR=1.00, 95% CI=0.14-7.16, P=1.00), heart failure (group A=4.31% vs group B=2.59%, OR=1.70, 95% CI=0.61-4.75, P=0.31), or CHB (0% vs 2.59%, OR=0.07, 95% CI=0.00-1.34, P=0.08). There were no significant differences in the secondary endpoints of recurrent angina, readmission, and tachyarrhythmias except for more first- and second-degree AV blocks with metoprolol (12.93% vs 2.59%, OR=5.59, 95% CI=2.28-13.72, P=0.0002). Ivabradine is well tolerated and equally effective as metoprolol in acute inferior wall ST elevation myocardial infarction patients for lowering the heart rate with lesser risk of AV blocks. © 2017 John Wiley & Sons Ltd.

A rare coexistence of complete atrioventricular block and preexcitation in an elderly symptomatic patient.

PubMed

Erdogan, Okan

2008-07-01

The present case report describes an elderly patient with complete atrioventricular nodal block coexisting with intermittent preexcitation, which resulted in paroxysmal complete loss of atrioventricular conduction and symptoms. The patient ended up with pacemaker implantation without requiring ablation of accessory pathway.

VDD vs DDD pacemakers: a meta-analysis.

PubMed

Shurrab, Mohammed; Elitzur, Yair; Healey, Jeff S; Gula, Lorne; Kaoutskaia, Anna; Israel, Carsten; Lau, Ching; Crystal, Eugene

2014-11-01

Dual-chamber (DDD) and VDD pacing are recognized alternatives for patients with advanced atrioventricular (AV) conduction abnormalities and spared sinus node function. The comparative data between these 2 modes are limited. A literature search was performed using multiple major databases. Outcomes of interest were (1) adverse events including incidence of atrial fibrillation (AF) and (2) procedural parameters. Odds ratio (OR) was reported for dichotomous variables and standardized mean difference (SMD) for continuous variables. Eight controlled studies (7 cohorts and 1 randomized controlled trial: total 1942 patients) were included. VDD mode was used in 922 patients. Mean follow-up period for the VDD group was 51 ± 24 months. There was a trend toward lower overall adverse events in the VDD group (9.6% vs 11.6%; OR, 0.74 [95% confidence interval (CI), 0.51-1.05; P = 0.09]). Shorter implantation and fluoroscopy times were noted with VDD pacing (46.2 ± 12 vs 65.9 ± 20 minutes; SMD, -0.96 [95% CI, -1.26 to -0.66; P < 0.0001] and 4.6 ± 1 vs 9.3 ± 0.4 minutes; SMD, -0.83 [95% CI, -1.38 to -0.29; P = 0.003], respectively). Mean P-wave amplitude was significantly lower in VDD (1.5 ± 0.8 mV vs 3.1 ± 0.9 mV; P = 0.02). The incidence of AF was lower in the VDD group but it did not reach statistical significance (7.5% vs 13.0%; OR, 0.7; 95% CI, 0.39-1.27; P = 0.24). This meta-analysis suggests that VDD is a reasonable alternative to DDD pacemakers with lower pneumothorax risk and shorter implantation and fluoroscopy times. More high-quality data are required to definitively compare the 2 strategies. Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Impact of Age and Polytherapy on Fingolimod Induced Bradycardia: a Preclinical Study.

PubMed

Ritter, Christian; Svačina, Martin K R; Bobylev, Ilja; Joshi, Abhijeet; Schneider, Toni; Lehmann, Helmar C

2017-03-01

Fingolimod is a an oral disease modifying drug for relapsing remitting multiple sclerosis (MS) preventing egress of B and T cells from lymph nodes. Relevant first dose adverse events include bradycardia and atrioventricular conduction slowing. Cardiac side effects of fingolimod and combinational pharmacotherapy including duloxetine and tolterodine were monitored in mice of different age using implantable ECG telemetric systems. Cardiac tissue was assessed for S1P-receptor subtype (1 and 3), and for GIRK1 expression. Fingolimod led to a significant heart rate reduction within 60 min, which returned to baseline values within 24 h. In older mice bradycardia was more pronounced compared to younger mice. Atrioventricular conduction was not affected. Older mice showed a higher S1PR3 expression in a naïve state and receptor expression was reduced after fingolimod administration. Combination with duloxetine or tolterodine alleviated fingolimod induced heart rate decrease. Our data provide preclinical evidence that negative chronotropic effects of fingolimod might be age dependent, possibly due to an altered expression and internalization of cardiac S1PR3 in older animals. This data could be relevant for future clinical monitoring and patient selection in the aging MS population. Combinational therapies of fingolimod and duloxetine or tolterodine are well tolerated and safe without an increased risk for pronounced bradycardia or arrhythmia.

The use of sugammadex in a pregnant patient with Wolff-Parkinson-White syndrome.

PubMed

Sengul, Turker; Saracoglu, Ayten; Sener, Sibel; Bezen, Olgac

2016-09-01

Wolff-Parkinson-White (WPW) syndrome is a rare pre-excitation syndrome which develops when atrioventricular conduction occurs through a pathologic accessory pathway known as the bundle of Kent instead of atrioventricular node, hence resulting in tachycardia. Patients with WPW syndrome may experience various symptoms arising from mild-to-moderate chest disease, palpitations, hypotension, and severe cardiopulmonary dysfunction. These patients are most often symptomatic because of cardiac arrhythmias. In this case report, we present an uneventful anesthetic management of a pregnant patient with WPW syndrome undergoing cesarean delivery. A 23-year-old American Society of Anesthesiologists class 2 pregnant patient was diagnosed with WPW syndrome. Her preoperative 12-lead electrocardiogram showed a sinus rhythm at 82 beats per minute, a delta wave, and a short PR interval. After an uneventful surgery, sugammadex 2mg/kg was administered as a reversal agent instead of neostigmine. Then she was discharged to her obstetrics service. Serious hemodynamic disorders may occur in patients with WPW syndrome due to development of fatal arrhythmias. Neostigmine used as a reversal agent in general anesthesia can trigger such fatal arrhythmias by leading changes in cardiac conduction. We believe that sugammadex, which is safely used in many areas in the scope of clinical practice, can be also used for patients diagnosed with WPW syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.

The New Concept of Univentricular Heart

PubMed Central

Frescura, Carla; Thiene, Gaetano

2014-01-01

The concept of univentricular heart moved from hearts with only one ventricle connected with atria [double inlet ventricle or absent atrioventricular (AV) connection] to hearts not amenable to biventricular repair, namely hearts with two ventricles unable to sustain separately pulmonary and systemic circulations in sequence. In the latter definition, even hearts with one hypoplastic ventricle are considered “functional” univentricular hearts. They include pulmonary/aortic atresia or severe stenosis with hypoplastic ventricle, and rare conditions like huge intramural cardiac tumors and Ebstein anomaly with extreme atrialization of right ventricular cavity. In this setting, the surgical repair is univentricular with “Fontan” operation, bypassing the ventricular mass. In other words, functionally univentricular heart is a condition in which, after surgery, only one ventricle sustain systemic circulation. Univentricular hearts (double inlet or absent AV connection) almost invariably show two ventricular chambers, one main and one accessory, which lacks an inlet portion. The latter is located posteriorly when morphologically left and anteriorly when morphologically right. As far as double inlet left ventricle, this is usually associated with discordant ventriculo-arterial (VA) connection (transposition of the great arteries) and all the blood flow to the aorta, which takes origin from the hypoplastic anterior right ventricle, is ventricular septal defect (bulbo-ventricular foramen) dependent. If restrictive, an aortic arch obstruction may be present. Double inlet left ventricle may be rarely associated with VA concordance (Holmes heart). As far as double inlet right ventricle with posterior hypoplastic left ventricular cavity, ventriculo-arterial connection is usually of double outlet type; thus the term double inlet–outlet right ventricle may be coined. Absent right or left AV connection may develop in the setting of both d- or l-loop, whatever the situs. In this condition, the contra-lateral patent AV valve may be either mitral or tricuspid in terms of morphology and the underlying ventricle (main chamber) either morphologically left or right. Establishing the loop, whatever right or left (also called right or left ventricular topology), is a fundamental step in the segmental-sequential analysis of congenital heart disease. PMID:25072035

Near-field multiple traps of paraxial acoustic vortices with strengthened gradient force generated by sector transducer array

NASA Astrophysics Data System (ADS)

Wang, Qingdong; Li, Yuzhi; Ma, Qingyu; Guo, Gepu; Tu, Juan; Zhang, Dong

2018-01-01

In order to improve the capability of particle trapping close to the source plane, theoretical and experimental studies on near-field multiple traps of paraxial acoustic vortices (AVs) with a strengthened acoustic gradient force (AGF) generated by a sector transducer array were conducted. By applying the integration of point source radiation, numerical simulations for the acoustic fields generated by the sector transducer array were conducted and compared with those produced by the circular transducer array. It was proved that strengthened AGFs of near-field multiple AVs with higher peak pressures and smaller vortex radii could be produced by the sector transducer array with a small topological charge. The axial distributions of the equivalent potential gradient indicated that the AGFs of paraxial AVs in the near field were much higher than those in the far field, and the distances at the near-field vortex antinodes were also proved to be the ideal trapping positions with relatively higher AGFs. With the established 8-channel AV generation system, theoretical studies were also verified by the experimental measurements of pressure and phase for AVs with various topological charges. The formation of near-field multiple paraxial AVs was verified by the cross-sectional circular pressure distributions with perfect phase spirals around central pressure nulls, and was also proved by the vortex nodes and antinodes along the center axis. The favorable results demonstrated the feasibility of generating near-field multiple traps of paraxial AVs with strengthened AGF using the sector transducer array, and suggested the potential applications of close-range particle trapping in biomedical engineering.

Effect of interconnection between cervical vagus trunk, epicardial fat pad on sinus node function, and atrial fibrillation.

PubMed

Zhou, Qina; Zhang, Ling; Wang, Kun; Xu, Xiaoxia; Ji, Meng; Zhang, Feng; Wang, Hongli; Hou, Yuemei

2014-03-01

The epicardial fat pad (FP) integrates the autonomic innervation between the extrinsic and intrinsic cardiac autonomic nervous system and affects atrial electrophysiology and pathophysiology. Eighteen dogs were divided into two groups: sequential ablation of sinoatrial node FP (SAN-FP) and atrioventricular node FP (AVN-FP). Sinus rate (SR), atrial fibrillation (AF) inducibility, and effective refractory period (ERP) changes during electrical stimulation of the vagus trunk were detected before and after ablation. In the SAN-FP group, the SR slowing, increasing AF inducibility, and ERP shortening that induced by vagus trunk stimulation were significantly attenuated by isolated SAN-FP ablation, compared with the same group prior to ablation (all P < 0.05). Subsequent AVN-FP ablation following SAN-FP ablation almost cannot produce further attenuation during vagus trunk stimulation, compared with isolated SAN-FP ablation (P > 0.05). In the AVN-FP group, SR slowing, increasing AF inducibility, and ERP shortening that induced by vagus trunk stimulation were completely eliminated by isolated AVN-FP ablation, compared with the same group prior to ablation (all P < 0.05). Subsequent SAN-FP ablation following AVN-FP ablation produced no further attenuation, compared with isolated AVN-FP ablation (P > 0.05). A neural pathway from the cervical vagus trunk to the sinus node and atrium runs through the SAN-FP, but eventually converges at the AVN-FP and also suggested that the AVN-FP serves as an "integration center" for the SAN-FP to modulate sinus node function. The AVN-FP may play a more critical role in the initiation and maintenance of AF. ©2013 First Affilated Hospital of Xingiang Medical University Pacing and Clinical Electrophysiology ©2013 Wiley Periodicals, Inc.

Benzodiazepine-associated atrioventricular block.

PubMed

Arroyo Plasencia, Anna M; Ballentine, Lynn M; Mowry, James B; Kao, Louise W

2012-01-01

Dysrhythmias, although common in overdose situations, are not often seen after benzodiazepine exposures. We report two cases of transient atrioventricular block after benzodiazepine misuse. Case 1 is a 4-year-old boy who was found unresponsive after an ingestion of clonazepam. An electrocardiogram (EKG) performed on emergency department presentation demonstrated first-degree atrioventricular block (PR 206 ms). After flumazenil administration, he developed second-degree atrioventricular block (Mobitz Type 1). EKG abnormalities resolved by morning. Serum clonazepam was 478 ng/mL (laboratory clonazepam reference range, 10-75 ng/mL with a dose of up to 6 mg/day) 5 hours after being found unresponsive. Case 2 is a 23-year-old man who presented to the emergency department after ingesting risperidone, combination hydrocodone/acetaminophen, and alprazolam. On arrival, his EKG demonstrated sinus bradycardia with a PR interval of 182 msec. He subsequently developed second-degree atrioventricular block (Mobitz Type I). Sinus bradycardia with resolution of his atrioventricular block (PR 200 ms) was seen on a third EKG performed 5 hours after presentation. These two patients demonstrated transient first- and second-degree atrioventricular block after benzodiazepine exposure. Benzodiazepines have been shown to alter L-type Ca2+ channel function. This alteration in function may account for the dysrhythmias seen in our patients. Together, these cases serve to remind clinicians of this rare but potentially serious complication associated with benzodiazepine exposure.

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

PubMed

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

2013-08-01

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

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

PubMed

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

2018-03-07

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

Multi-level tree analysis of pulmonary artery/vein trees in non-contrast CT images

NASA Astrophysics Data System (ADS)

Gao, Zhiyun; Grout, Randall W.; Hoffman, Eric A.; Saha, Punam K.

2012-02-01

Diseases like pulmonary embolism and pulmonary hypertension are associated with vascular dystrophy. Identifying such pulmonary artery/vein (A/V) tree dystrophy in terms of quantitative measures via CT imaging significantly facilitates early detection of disease or a treatment monitoring process. A tree structure, consisting of nodes and connected arcs, linked to the volumetric representation allows multi-level geometric and volumetric analysis of A/V trees. Here, a new theory and method is presented to generate multi-level A/V tree representation of volumetric data and to compute quantitative measures of A/V tree geometry and topology at various tree hierarchies. The new method is primarily designed on arc skeleton computation followed by a tree construction based topologic and geometric analysis of the skeleton. The method starts with a volumetric A/V representation as input and generates its topologic and multi-level volumetric tree representations long with different multi-level morphometric measures. A new recursive merging and pruning algorithms are introduced to detect bad junctions and noisy branches often associated with digital geometric and topologic analysis. Also, a new notion of shortest axial path is introduced to improve the skeletal arc joining two junctions. The accuracy of the multi-level tree analysis algorithm has been evaluated using computer generated phantoms and pulmonary CT images of a pig vessel cast phantom while the reproducibility of method is evaluated using multi-user A/V separation of in vivo contrast-enhanced CT images of a pig lung at different respiratory volumes.

Complications of pacemaker therapy in adults with congenital heart disease: a multicenter study.

PubMed

Opić, Petra; van Kranenburg, Matthijs; Yap, Sing-Chien; van Dijk, Arie P; Budts, Werner; Vliegen, Hubert W; van Erven, Lieselot; Can, Anil; Sahin, Gulhan; Theuns, Dominic A M J; Witsenburg, Maarten; Roos-Hesselink, Jolien W

2013-10-09

This study aims to investigate indications and complications of permanent cardiac pacing in adults with congenital heart disease (CHD). Two-hundred and seventy-four CHD patients were identified who underwent permanent pacemaker implantation between 1972 and 2009. The indication for pacing was acquired sinus node or AV node conduction disease (63%), sinus node or AV node conduction disease after cardiac surgery (28%), and drug/arrhythmia-related indications (9%). Patients with complex CHD received a pacemaker at younger age (23 versus 31 years, p<0.0001) and more often received an epicardial pacing system (51% versus 23%, p<0.0001) compared to those with simple or moderate CHD. Twenty-nine patients (10.6%) had a periprocedural complication during the primary pacemaker implantation (general population: 5.2%). The most common acute complications were lead dysfunction (4.0%), bleeding (2.6%), pocket infection (1.5%) and pneumothorax (1.5%). During a median follow-up of 12 years, pacemaker-related complications requiring intervention occurred in 95 patients (34.6%). The most common late pacemaker-related complications included lead failure (24.8%), pacemaker dysfunction/early battery depletion (5.1%), pacemaker migration (4.7%) and erosion (4.7%). Pacemaker implantation at younger age (<18 years) was an independent predictor of late pacemaker-related complication (adjusted hazard ratio 1.68, 95% confidence interval 1.07 to 2.63, p=0.023). The risk of periprocedural complications seems higher in the CHD population compared to the general population and more than one-third of CHD patients encountered a pacemaker-related complication during long-term follow-up. This risk increases for those who receive a pacemaker at younger age. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

[Comparative study of the effects of verapamil, ethmozin and ethacizine on provoked attacks of atrioventricular nodal reciprocal tachycardia].

PubMed

Smetnev, A S; Islam, M N; Sokolov, S F; Golitsyn, S P; Bankuzov, V A; Malakhov, V I

1990-02-01

27 patients underwent serial electrophysiological studies by using transesophageal atrial stimulation. A-V nodal reciprocal tachycardia was documented by intracardiac electrophysiological examinations. Sustained tachycardia was induced in all the patients before drug administration. On day 4 after oral verapamil, 320 mg/day, ethmosine, 800 mg/day, and ethacizine, 150 mg/day, the patients were subjected to transesophageal atrial stimulation. An antiarrhythmic effect was regarded to be reached if the authors failed to induced sustained tachycardias again. Verapamil, ethmosine, and ethacizine were found to be beneficial in 21 (78%), 13 (48%) and 21 (78%) patients, respectively. A comparative analysis demonstrated that ethacisine was not inferior to verapamil, but ethmosine produced less effects than verapamil and ethacizine. The crossover and individual efficacy shown by each drug suggests that it is necessary to use the technique of serial testing and to choose beneficial drugs from a possibly wide range of medicaments for each patient.

Down Syndrome with Complete Atrioventricular Septal Defect, Hypertrophic Cardiomyopathy, and Pulmonary Vein Stenosis.

PubMed

Mahadevaiah, Guruprasad; Gupta, Manoj; Ashwath, Ravi

2015-10-01

The prevalence of congenital heart disease in infants with Down syndrome is 40%, compared with 0.3% in children who have normal chromosomes. Atrioventricular and ventricular septal defects are often associated with chromosomal aberrations, such as in trisomy 21, whereas hypertrophic cardiomyopathy is chiefly thought to be secondary to specific gene mutations. We found only one reported case of congenital hypertrophic cardiomyopathy and atrioventricular septal defect in an infant with Down syndrome. Here, we report atrioventricular septal defect, hypertrophic cardiomyopathy, and pulmonary vein stenosis in a neonate with Down syndrome-an apparently unique combination. In addition, we discuss the relevant medical literature.

Review of the If selective channel inhibitor ivabradine in the treatment of chronic stable angina.

PubMed

Prasad, Usha K; Gray, David; Purcell, Henry

2009-02-01

Coronary heart disease is the major cause of morbidity and mortality in industrialized countries, and its prevalence is predicted to grow as the population ages. Current drugs for chronic stable angina (such as beta-blockers, calcium-channel blockers, long- and short-acting nitrates, and potassium-channel activators) are often effective, either as monotherapy or in combination, but side effects and contraindications may limit their use. The "I(f)" (for "funny") channel, discovered in 1979, is expressed mainly in the membrane of pacemaker cells present in the sinus node, the atrioventricular node, the ventricular conduction pathways, and ventricular myocytes. By determining the slope of diastolic depolarization, which in turn controls action potential frequency, it is a key determinant of heart rate and so provides a new therapeutic target for controlling angina symptoms. A new antiangina drug, ivabradine, has been developed and licensed for clinical use. It exclusively reduces the heart rate by selectively blocking the I(f) channel of the sino-atrial node. As clinical trials have shown it to be remarkably well-tolerated, ivabradine offers an alternative for patients who cannot take, or are intolerant of, beta blockade. This review provides an insight into this new agent, its historical background, mechanism of action, and pathophysiologic basis, and provides up-to-date evidence-based information on its optimum use in stable angina.

[Ebstein's "like" anomaly ventricular double inlet. A rare association].

PubMed

Muñoz Castellanos, Luis; Kuri Nivon, Magdalena

The association of univentricular heart with double inlet and Ebstein's "like" anomaly of the common atrioventricular valve is extremely rare. Two hearts with this association are described with the segmental sequential system which determine the atrial situs, the types of atrioventricular and ventriculoarterial connections and associated anomalies. Both hearts had atrial situs solitus, and a univentricular heart with common atrioventricular valve, a foramen primum and double outlet ventricle with normal crossed great arteries. In the fiefirst heart the four leaflets of the atrioventricular valve were displaced and fused to the ventricular walls, from the atrioventricular union roward the apex with atrialization of the inlet and trabecular zones and there was stenosis in the infundibulum and in the pulmonary valve. In the second heart the proximal segment of the atrioventricular valve was displaced and fused to the ventricular whith shot atrialization and the distal segment was dysplastic with fibromixoid nodules and tendinous cords short and thick; the pulmonary artery was dilate. Both hearts are grouped in the atrioventricular univentricular connection in the segmental sequential system. The application of this method in the diagnosis of congenital heart disease demonstrates its usefulness. The associations of complex anomalies in these hearts show us the infinite spectrum of presentation of congenital heart disease which expands our knowledge of pediatric cardiology. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

An alternative technique for orthotopic cardiac transplantation, with preservation of the normal anatomy of the right atrium.

PubMed

Sievers, H H; Weyand, M; Kraatz, E G; Bernhard, A

1991-04-01

The standard technique for orthotopic cardiac transplantation implies large atrial anastomoses which do not preserve the anatomical integrity of the donor atria. This may become a potential source of electrophysiological and mechanical atrial dysfunction, especially in the right atrium with the sinus node and the sensitive low-pressure atrioventricular valve. As an improvement we suggest an alternative technique which we have recently developed for orthotopic cardiac transplantation; it combines the simple, convenient left atrial connection of the standard technique with individual anastomoses of the superior and inferior venae cavae, preserving the right atrium of the donated heart intact. This technique and our first results in two cases are described. Postoperatively, no arrhythmias and no signs of tricuspid insufficiency were observed.

Neuropeptide tyrosine (NPY)--a major cardiac neuropeptide.

PubMed

Gu, J; Polak, J M; Adrian, T E; Allen, J M; Tatemoto, K; Bloom, S R

1983-05-07

A newly discovered bioactive peptide, neuropeptide tyrosine (NPY), has been found in the human cardiac nervous system. Dense concentrations of NPY-immunoreactive nerve fibres were found in association with nodal tissue (atrioventricular node 22.1 +/- 3.7 pmol/g). NPY nerve fibres were seen in close contact with cardiac muscle fibres and were also found around the coronary vessels (19.6 +/- 6.2 pmol/g). Analysis of the peptide by high-performance liquid chromatography demonstrated that it was present in a single molecular form, closely similar or identical to that of the isolated bioactive peptide. Cardiac function in man has long been known to be influenced by cholinergic and adrenergic nerves. There now appears to be a further component of the nervous system in the human heart, involving peptidergic nerves containing NPY.

How revealing are insertable loop recorders in pediatrics?

PubMed

Frangini, Patricia A; Cecchin, Frank; Jordao, Ligia; Martuscello, Maria; Alexander, Mark E; Triedman, John K; Walsh, Edward P; Berul, Charles I

2008-03-01

An insertable loop recorder (ILR) in patients with infrequent syncope or palpitations may be useful to decide management strategies, including clinical observation, medical therapy, pacemaker, or implantable cardioverter defibrillator (ICD). We sought to determine the diagnostic utility of the Reveal ILR (Medtronic, Inc., Minneapolis, MN, USA) in pediatric patients. Retrospective review of clinical data, indications, findings, and therapeutic decision in 27 consecutive patients who underwent ILR implantation from 1998-2007. The median age was 14.8 years (2-25 years). Indications were syncope in 24 patients and recurrent palpitations in three. Overall, eight patients had structural heart disease (six congenital heart disease, one hypertrophic cardiomyopathy, one Kawasaki), five had previous documented ventricular arrhythmias with negative evaluation including electrophysiology study, and three patients had QT prolongation. Tilt testing was performed in 10 patients, of which five had neurocardiogenic syncope but recurrent episodes despite medical therapy. After median three months (1-20 months), 17 patients presented with symptoms and the ILR memory was analyzed in 16 (no episode stored in one due to full device memory), showing asystole or transient atrioventricular (AV) block (2), sinus bradycardia (6), or normal sinus rhythm (8). Among asymptomatic patients, 3/10 had intermittent AV block or long pauses, automatically detected and stored by the ILR. In 19 of 20 patients, ILR was diagnostic (95%) and five subsequently underwent pacemaker implantation, while seven patients remained asymptomatic without ILR events. Notably, no life-threatening events were detected. The ILR was explanted in 22 patients after a median of 22 months, two due to pocket infection, 12 for battery depletion and eight after clear documentation of nonmalignant arrhythmia. The ILR in pediatrics is a useful adjunct to other diagnostic studies. Patient selection is critical as the ILR should not be utilized for malignant arrhythmias. A diagnosis is attained in the majority of symptomatic patients, predominantly bradyarrhythmias including pauses and intermittent AV block.

The magnetic navigation system allows safety and high efficacy for ablation of arrhythmias

PubMed Central

Bauernfeind, Tamas; Akca, Ferdi; Schwagten, Bruno; de Groot, Natasja; Van Belle, Yves; Valk, Suzanne; Ujvari, Barbara; Jordaens, Luc; Szili-Torok, Tamas

2011-01-01

Aims We aimed to evaluate the safety and long-term efficacy of the magnetic navigation system (MNS) in a large number of patients. The MNS has the potential for improving safety and efficacy based on atraumatic catheter design and superior navigation capabilities. Methods and results In this study, 610 consecutive patients underwent ablation. Patients were divided into two age- and sex-matched groups. Ablations were performed either using MNS (group MNS, 292) or conventional manual ablation [group manual navigation (MAN), 318]. The following parameters were analysed: acute success rate, fluoroscopy time, procedure time, complications [major: pericardial tamponade, permanent atrioventricular (AV) block, major bleeding, and death; minor: minor bleeding and temporary AV block]. Recurrence rate was assessed during follow-up (15 ± 9.5 months). Subgroup analysis was performed for the following groups: atrial fibrillation, isthmus dependent and atypical atrial flutter, atrial tachycardia, AV nodal re-entrant tachycardia, circus movement tachycardia, and ventricular tachycardia (VT). Magnetic navigation system was associated with less major complications (0.34 vs. 3.2%, P = 0.01). The total numbers of complications were lower in group MNS (4.5 vs. 10%, P = 0.005). Magnetic navigation system was equally effective as MAN in acute success rate for overall groups (92 vs. 94%, P = ns). Magnetic navigation system was more successful for VTs (93 vs. 72%, P < 0.05). Less fluoroscopy was used in group MNS (30 ± 20 vs. 35 ± 25 min, P < 0.01). There were no differences in procedure times and recurrence rates for the overall groups (168 ± 67 vs. 159 ± 75 min, P = ns; 14 vs. 11%, P = ns; respectively). Conclusions Our data suggest that the use of MNS improves safety without compromising efficiency of ablations. Magnetic navigation system is more effective than manual ablation for VTs. PMID:21508006

A Genome-Wide Association Study to Identify Genomic Modulators of Rate Control Therapy in Patients with Atrial Fibrillation

PubMed Central

Kolek, Matthew J.; Edwards, Todd L.; Muhammad, Raafia; Balouch, Adnan; Shoemaker, M. Benjamin; Blair, Marcia A.; Kor, Kaylen C.; Takahashi, Atsushi; Kubo, Michiaki; Roden, Dan M.; Tanaka, Toshihiro; Darbar, Dawood

2014-01-01

For many patients with atrial fibrillation (AF), ventricular rate control with atrioventricular (AV) nodal blockers is considered first-line therapy, though response to treatment is highly variable. Using an extreme phenotype of failure of rate control necessitating AV nodal ablation and pacemaker implantation, we conducted a genome wide association study (GWAS) to identify genomic modulators of rate control therapy. Cases included 95 patients who failed rate control therapy. Controls (N=190) achieved adequate rate control therapy with ≤2 AV nodal blockers using a conventional clinical definition. Genotyping was performed on the Illumina 610-Quad platform, and results were imputed to the 1000 Genomes reference haplotypes. 554,041 single nucleotide polymorphisms (SNPs) met criteria for minor allele frequency (>0.01), call rate (>95%), and quality control, and 6,055,224 SNPs were available after imputation. No SNP reached the canonical threshold for significance for GWAS of P<5 × 10−8. Sixty-three SNPs with P<10−5 at 6 genomic loci were genotyped in a validation cohort of 130 cases and 157 controls. These included 6q24.3 (near SAMD5/SASH1, P=9.36 × 10−8), 4q12 (IGFBP7, P=1.75 × 10−7), 6q22.33 (C6orf174, P=4.86 × 10−7), 3p21.31 (CDCP1, P=1.18 × 10−6), 12p12.1 (SOX5, P=1.62 × 10−6), and 7p11 (LANCL2, P=6.51 × 10−6). However, none of these were significant in the replication cohort or in a meta-analysis of both cohorts. In conclusion, we identified several potentially important genomic modulators of rate control therapy in AF, particularly SOX5, which was previously associated with resting heart rate and PR interval. However these failed to reach genome-wide significance. PMID:25015694

Surgical treatment of atrioventricular canal defect.

PubMed

Hardesty, R L; Zuberbuhler, J R; Bahnson, H T

1975-11-01

Fifty-nine patients with congenital anomalies of the atrioventricular canal underwent operation and all survivors were followed up. In 42 patients with partial atrioventricular canal defects, ten had preoperative congestive heart failure. Three, or 7.1%, died of endomyocardial fibroelastosis, high pulmonary vascular resistance, and severe mitral regurgitation. A fourth patient later died of Wolff-Parkinson-White syndrome and fibrilation. Reoperations in five patients were all successful. No patients had persistent atrioventricular blocks, and all patients are asymptomatic. Two of these subjects continue to receive digoxin therapy, and one of them is believed to have substantial mitral insufficiency. Of the 17 patients who had complete atrioventricular canal defects, 13 had a divided common anterior leaflet attached to the septum by chordae tendineae, and four had undivided and unattached anterior leaflets. Two had previously undergone pulmonary banding, and nine were treated for congestive heart failure. Six died after operation. There were no reoperations. No patient presently has required a pacemaker. Two subjects have persistent cardiomegaly.

Complete atrioventricular canal.

PubMed

Calabrò, Raffaele; Limongelli, Giuseppe

2006-04-05

Complete atrioventricular canal (CAVC), also referred to as complete atrioventricular septal defect, is characterised by an ostium primum atrial septal defect, a common atrioventricular valve and a variable deficiency of the ventricular septum inflow. CAVC is an uncommon congenital heart disease, accounting for about 3% of cardiac malformations. Atrioventricular canal occurs in two out of every 10,000 live births. Both sexes are equally affected and a striking association with Down syndrome was found. Depending on the morphology of the superior leaflet of the common atrioventricular valve, 3 types of CAVC have been delineated (type A, B and C, according to Rastelli's classification). CAVC results in a significant interatrial and interventricular systemic-to-pulmonary shunt, thus inducing right ventricular pressure and volume overload and pulmonary hypertension. It becomes symptomatic in infancy due to congestive heart failure and failure to thrive. Diagnosis of CAVC might be suspected from electrocardiographic and chest X-ray findings. Echocardiography confirms it and gives anatomical details. Over time, pulmonary hypertension becomes irreversible, thus precluding the surgical therapy. This is the reason why cardiac catheterisation is not mandatory in infants (less than 6 months) but is indicated in older patients if irreversible pulmonary hypertension is suspected. Medical treatment (digitalis, diuretics, vasodilators) plays a role only as a bridge toward surgery, usually performed between the 3rd and 6th month of life.

A critical role for the EphA3 receptor tyrosine kinase in heart development.

PubMed

Stephen, Lesley J; Fawkes, Amy L; Verhoeve, Adam; Lemke, Greg; Brown, Arthur

2007-02-01

Eph proteins are receptor tyrosine kinases that control changes in cell shape and migration during development. We now describe a critical role for EphA3 receptor signaling in heart development as revealed by the phenotype of EphA3 null mice. During heart development mesenchymal outgrowths, the atrioventricular endocardial cushions, form in the atrioventricular canal. This morphogenetic event requires endocardial cushion cells to undergo an epithelial to mesenchymal transformation (EMT), and results in the formation of the atrioventricular valves and membranous portions of the atrial and ventricular septa. We show that EphA3 knockouts have significant defects in the development of their atrial septa and atrioventricular endocardial cushions, and that these cardiac abnormalities lead to the death of approximately 75% of homozygous EphA3(-/-) mutants. We demonstrate that EphA3 and its ligand, ephrin-A1, are expressed in adjacent cells in the developing endocardial cushions. We further demonstrate that EphA3(-/-) atrioventricular endocardial cushions are hypoplastic compared to wildtype and that EphA3(-/-) endocardial cushion explants give rise to fewer migrating mesenchymal cells than wildtype explants. Thus our results indicate that EphA3 plays a crucial role in the development and morphogenesis of the cells that give rise to the atrioventricular valves and septa.

Identifying the Evolutionary Building Blocks of the Cardiac Conduction System

PubMed Central

Jensen, Bjarke; Boukens, Bastiaan J. D.; Postma, Alex V.; Gunst, Quinn D.; van den Hoff, Maurice J. B.; Moorman, Antoon F. M.; Wang, Tobias; Christoffels, Vincent M.

2012-01-01

The endothermic state of mammals and birds requires high heart rates to accommodate the high rates of oxygen consumption. These high heart rates are driven by very similar conduction systems consisting of an atrioventricular node that slows the electrical impulse and a His-Purkinje system that efficiently activates the ventricular chambers. While ectothermic vertebrates have similar contraction patterns, they do not possess anatomical evidence for a conduction system. This lack amongst extant ectotherms is surprising because mammals and birds evolved independently from reptile-like ancestors. Using conserved genetic markers, we found that the conduction system design of lizard (Anolis carolinensis and A. sagrei), frog (Xenopus laevis) and zebrafish (Danio rerio) adults is strikingly similar to that of embryos of mammals (mouse Mus musculus, and man) and chicken (Gallus gallus). Thus, in ectothermic adults, the slow conducting atrioventricular canal muscle is present, no fibrous insulating plane is formed, and the spongy ventricle serves the dual purpose of conduction and contraction. Optical mapping showed base-to-apex activation of the ventricles of the ectothermic animals, similar to the activation pattern of mammalian and avian embryonic ventricles and to the His-Purkinje systems of the formed hearts. Mammalian and avian ventricles uniquely develop thick compact walls and septum and, hence, form a discrete ventricular conduction system from the embryonic spongy ventricle. Our study uncovers the evolutionary building plan of heart and indicates that the building blocks of the conduction system of adult ectothermic vertebrates and embryos of endotherms are similar. PMID:22984480

Feasibility of Biventricular Repair in Right Dominant Unbalanced Atrioventricular Septal Defect: A New Echocardiographic Metric to Refine Surgical Decision-Making.

PubMed

Lugones, Ignacio; Biancolini, María Fernanda; Biancolini, Julio César; Dios, Ana M S de; Lugones, Germán

2017-07-01

Unbalanced forms of atrioventricular septal defect continue to be challenging and present poor surgical outcomes. Echocardiographic indicators such as atrioventricular valve index, right ventricle/left ventricle inflow angle, and size of the ventricular septal defect have been identified as relevant discriminators that may guide surgical strategy. Our purpose is to describe another metric to refine surgical decision-making. We outline a geometrical description of the anatomic features of atrioventricular septal defect and describe equations that help explain the interplay between the main echocardiographic variables. A new metric called "indexed ventricular septal defect" is defined as the size of the defect in relation to the valve diameter. We derive a final equation relating this index with the atrioventricular valve index and the right ventricle/left ventricle inflow angle. In the light of that equation, we discuss the interdependence of variables and employ data from a Congenital Heart Surgeons' Society study to set the limits of the new index. Combined use of indexed ventricular septal defect and atrioventricular valve index might help clarify surgical decision-making in patients with mild and moderate unbalance (modified atrioventricular valve index between 0.2 and 0.39). For indexed ventricular septal defect smaller than 0.2, biventricular repair may be recommended. Between 0.2 and 0.35, this strategy could probably be achieved depending on other factors. However, other strategies should be considered for those patients showing an indexed ventricular septal defect between 0.35 and 0.5. For values above 0.5 to 0.55, univentricular palliation might be a reasonable strategy.

Electrophysiological properties of myocytes isolated from the mouse atrioventricular node: L-type ICa, IKr, If, and Na-Ca exchange

PubMed Central

Choisy, Stéphanie C; Cheng, Hongwei; Orchard, Clive H; James, Andrew F; Hancox, Jules C

2015-01-01

The atrioventricular node (AVN) is a key component of the cardiac pacemaker-conduction system. This study investigated the electrophysiology of cells isolated from the AVN region of adult mouse hearts, and compared murine ionic current magnitude with that of cells from the more extensively studied rabbit AVN. Whole-cell patch-clamp recordings of ionic currents, and perforated-patch recordings of action potentials (APs), were made at 35–37°C. Hyperpolarizing voltage commands from −40 mV elicited a Ba2+-sensitive inward rectifier current that was small at diastolic potentials. Some cells (Type 1; 33.4 ± 2.2 pF; n = 19) lacked the pacemaker current, If, whilst others (Type 2; 34.2 ± 1.5 pF; n = 21) exhibited a clear If, which was larger than in rabbit AVN cells. On depolarization from −40 mV L-type Ca2+ current, ICa,L, was elicited with a half maximal activation voltage (V0.5) of −7.6 ± 1.2 mV (n = 24). ICa,L density was smaller than in rabbit AVN cells. Rapid delayed rectifier (IKr) tail currents sensitive to E-4031 (5 μmol/L) were observed on repolarization to −40 mV, with an activation V0.5 of −10.7 ± 4.7 mV (n = 8). The IKr magnitude was similar in mouse and rabbit AVN. Under Na-Ca exchange selective conditions, mouse AVN cells exhibited 5 mmol/L Ni-sensitive exchange current that was inwardly directed negative to the holding potential (−40 mV). Spontaneous APs (5.2 ± 0.5 sec−1; n = 6) exhibited an upstroke velocity of 37.7 ± 16.2 V/s and ceased following inhibition of sarcoplasmic reticulum Ca2+ release by 1 μmol/L ryanodine, implicating intracellular Ca2+ cycling in murine AVN cell electrogenesis. PMID:26607172

Safety and efficiency of ventricular pacing prevention with an AAI-DDD changeover mode in patients with sinus node disease or atrioventricular block: impact on battery longevity-a sub-study of the ANSWER trial.

PubMed

Stockburger, Martin; Defaye, Pascal; Boveda, Serge; Stancak, Branislav; Lazarus, Arnaud; Sipötz, Johann; Nardi, Stefano; Rolando, Mara; Moreno, Javier

2016-05-01

This ANSWER (EvaluAtioN of the SafeR mode in patients With a dual chambER pacemaker indication) sub-study assesses safety and effectiveness of SafeR™ and the impact of ventricular pacing (VP) prevention on anticipated device longevity and replacement rate. Patients implanted for atrioventricular block (AVB, n = 310) or sinus node dysfunction (SND, n = 336) were randomly assigned to SafeR (n = 314) or DDD (n = 318) and followed for 36 months. Safety, median VP, estimated device longevity (mean difference, 95% confidence interval [CI]), and anticipated replacement rates were analysed by pacing mode and implant indication. No difference in mortality, syncope, or mode intolerance was observed between randomization groups regardless of the indication. Ventricular pacing on SafeR vs. DDD was 11.5 vs. 93.6% in the overall population (P < 0.001), 89.2 vs. 83.8% in permanent AVB (P = 0.944), 53.5 vs. 98.2% in intermittent AVB (P < 0.001), and 2.2 vs. 84.7% in SND (P < 0.001). Anticipated median device longevity increased on SafeR by 14 [Q1 10; Q3 17] months [10; 17] (P < 0.001) in the overall population, 9 months [-5; 22] (P = 0.193) in permanent AVB, 14 months [8; 19] (P < 0.001) in intermittent AVB, and 14 months [9; 19] (P < 0.001) in SND. In intermittent AVB and SND, prolonged estimated battery longevity translated into the prevention of one anticipated replacement in at least 23% of patients. SafeR was effective in reducing VP in intermittent AVB and in SND. No effect was observed in permanent AVB. No safety issue was observed. Ventricular pacing reduction by SafeR translated into relevant estimated prolongation of device longevity and anticipated reduction of required replacements. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Facts about Atrioventricular Septal Defect (AVSD)

MedlinePlus

... Living With Heart Defects Data & Statistics Tracking & Research Articles & Key Findings Free Materials Multimedia and Tools Links to Other Websites Information For… Media Policy Makers Facts about Atrioventricular Septal Defect (AVSD) ...

Prevention of congenital defects induced by prenatal alcohol exposure (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sheehan, Megan M.; Karunamuni, Ganga; Pedersen, Cameron J.; Gu, Shi; Doughman, Yong Qiu; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

2017-02-01

Over 500,000 women per year in the United States drink during pregnancy, and 1 in 5 of this population also binge drink. Up to 40% of live-born children with prenatal alcohol exposure (PAE) present with congenital heart defects (CHDs) including life-threatening outflow and valvuloseptal anomalies. Previously we established a PAE model in the avian embryo and used optical coherence tomography (OCT) imaging to assay looping-stage (early) cardiac function/structure and septation-stage (late) cardiac defects. Early-stage ethanol-exposed embryos had smaller cardiac cushions (valve precursors) and increased retrograde flow, while late-stage embryos presented with gross head/body defects, and exhibited smaller atrio-ventricular (AV) valves, interventricular septae, and aortic vessels. However, supplementation with the methyl donor betaine reduced gross defects, prevented cardiac defects such as ventricular septal defects and abnormal AV valves, and normalized cardiac parameters. Immunofluorescent staining for 5-methylcytosine in transverse embryo sections also revealed that DNA methylation levels were reduced by ethanol but normalized by co-administration of betaine. Furthermore, supplementation with folate, another methyl donor, in the PAE model appeared to normalize retrograde flow levels which are typically elevated by ethanol exposure. Studies are underway to correlate retrograde flow numbers for folate with associated cushion volumes. Finally, preliminary findings have revealed that glutathione, a key endogenous antioxidant which also regulates methyl group donation, is particularly effective in improving alcohol-impacted survival and gross defect rates. Current investigations will determine whether glutathione has any positive effect on PAE-related CHDs. Our studies could have significant implications for public health, especially related to prenatal nutrition recommendations.

Automatic left-atrial segmentation from cardiac 3D ultrasound: a dual-chamber model-based approach

NASA Astrophysics Data System (ADS)

Almeida, Nuno; Sarvari, Sebastian I.; Orderud, Fredrik; Gérard, Olivier; D'hooge, Jan; Samset, Eigil

2016-04-01

In this paper, we present an automatic solution for segmentation and quantification of the left atrium (LA) from 3D cardiac ultrasound. A model-based framework is applied, making use of (deformable) active surfaces to model the endocardial surfaces of cardiac chambers, allowing incorporation of a priori anatomical information in a simple fashion. A dual-chamber model (LA and left ventricle) is used to detect and track the atrio-ventricular (AV) plane, without any user input. Both chambers are represented by parametric surfaces and a Kalman filter is used to fit the model to the position of the endocardial walls detected in the image, providing accurate detection and tracking during the whole cardiac cycle. This framework was tested in 20 transthoracic cardiac ultrasound volumetric recordings of healthy volunteers, and evaluated using manual traces of a clinical expert as a reference. The 3D meshes obtained with the automatic method were close to the reference contours at all cardiac phases (mean distance of 0.03+/-0.6 mm). The AV plane was detected with an accuracy of -0.6+/-1.0 mm. The LA volumes assessed automatically were also in agreement with the reference (mean +/-1.96 SD): 0.4+/-5.3 ml, 2.1+/-12.6 ml, and 1.5+/-7.8 ml at end-diastolic, end-systolic and pre-atrial-contraction frames, respectively. This study shows that the proposed method can be used for automatic volumetric assessment of the LA, considerably reducing the analysis time and effort when compared to manual analysis.

Current strategy for treatment of patients with Wolff-Parkinson-White syndrome and asymptomatic preexcitation in Europe: European Heart Rhythm Association survey.

PubMed

Svendsen, Jesper Hastrup; Dagres, Nikolaos; Dobreanu, Dan; Bongiorni, Maria Grazia; Marinskis, Germanas; Blomström-Lundqvist, Carina

2013-05-01

The aims of this survey was to provide insight into treatment activity, the strategy of treatment, and risk stratification of patients with asymptomatic and symptomatic ventricular pre-excitation across Europe. Fifty-eight centres, members of the European Heart Rhythm Association EP research network, covering 20 countries answered the survey questions. All centres were high-volume ablation centres. A younger person with asymptomatic Wolff-Parkinson-White (WPW) pattern has a higher likelihood of being risk-stratified or receiving ablation therapy compared with an older subject. Two-thirds of centres report that they have observed a decline in the number of patients ablated for an accessory pathway during the last 10 years. Pre-excited atrial fibrillation is rarely seen. Discontinuation of a scheduled WPW ablation due to close vicinity of the accessory pathway to the AV node happens very rarely. Patients with a first episode of pre-excited atrial fibrillation would immediately be referred for catheter ablation to be performed within weeks by 80.4% of the centres. A significant proportion of responders (50.9%) would use electrical cardioversion to restore sinus rhythm in a patient with pre-excited atrial fibrillation. With respect to the choice of antiarrhythmic medication for a patient with pre-excited AF, the majority (80.0%) would choose class 1C antiarrhytmic drugs while waiting for a catheter ablation. A patient seen in the emergency room with a second episode of orthodromic atrioventricular reentry tachycardia would be referred for immediate ablation by 79.2-90.6% of centres depending on the presence of pre-excitation. The volume of paediatric ablations performed on children younger than 12 years was low (46.4%: 0 patients per year; 46.4%: 1-9 patients per year). The majority of responding centres (61-69%) report that their country lack national guidelines dealing with clinical strategies related to WPW. There is a need for national guidelines dealing with clinical strategy in patients with WPW syndrome. Older individuals with asymptomatic WPW pattern have a higher risk of not receiving risk stratification or curative therapy with ablation compared with younger patients, despite the higher risk of developing atrial fibrillation.

Paroxysmal Mobitz type-I atrioventricular block Luciani-Wenckebach conduction, acute myocardial infarction and severe three vessels coronary artery disease.

PubMed

Patanè, Salvatore; Marte, Filippo

2009-06-12

Paroxysmal atrioventricular block has been reported in patients without acute coronary syndrome and without significant coronary artery stenosis, in patients with acute coronary syndrome and without significant coronary artery stenosis, in patients without acute coronary syndrome and with significant coronary artery stenosis and in patients with acute coronary syndrome and significant coronary artery stenosis. Conflicting roles for alternating periods of second degree atrioventricular block (also known as Mobitz I or Luciani-Wenckebach periodicity) have been reported. Both hypotheses have been reported, that paroxysmal Wenckebach periods are compatible with a benign prognosis and that paroxysmal Wenckebach periods are associated with hemodynamic deterioration. We present a case of paroxysmal Mobitz Type-I atrioventricular block Luciani-Wenckebach conduction in a 75-year-old Italian man with acute myocardial infarction and severe three vessels coronary artery disease.

Second-Degree Atrioventricular Block Occurring After Tooth Extraction.

PubMed

Kamatani, Takaaki; Akizuki, Ayako; Kondo, Seiji; Shirota, Tatsuo

Although cardiac arrhythmias are occasionally associated with dental extractions and dental anesthesia, atrioventricular block is rarely seen during dental procedures. We report a rare case of type I second-degree atrioventricular block (Wenckebach phenomenon) occurring after bilateral extraction of impacted mandibular third molars under general anesthesia in a 16-year-old Japanese girl. Under consultation with a cardiovascular physician, we carefully monitored the patient's vital signs postoperatively, including blood pressure, oxygen saturation, and electrocardiogram, using a bedside monitor. Her postoperative course was uneventful. A 12-lead electrocardiogram the following day revealed no abnormality. In this case, we hypothesize that extubation of the nasotracheal tube or oral/pharyngeal suction might have triggered a vagal reflex that caused type I second-degree atrioventricular block. Our experience indicates that standard cardiovascular monitoring should be used for patients undergoing dental treatment under general anesthesia, even for young, healthy patients, to prevent and detect cardiovascular emergencies.

Value of an old school approach: safety and long-term success of radiofrequency current catheter ablation of atrioventricular nodal reentrant tachycardia in children and young adolescents.

PubMed

Siebels, Henrike; Sohns, Christian; Nürnberg, Jan-Hendrik; Siebels, Jürgen; Langes, Klaus; Hebe, Joachim

2018-05-15

Radiofrequency current energy (RFC) ablation is still considered as the gold standard for atrioventricular nodal reentrant tachycardia (AVNRT). Success-rates for AVNRT ablation vary irrespective of the ablation technology and strategy. This study aimed to access safety, efficacy, and long-term outcome of RFC catheter ablation for the treatment of AVNRT in children and adolescents aged < 19 years with special focus on modulation versus ablation of the AV nodal slow pathway (SP). A total number of 1143 patients (pts) < 19 years were referred for invasive electrophysiological testing due to paroxysmal supraventricular tachycardia (SVT). Diagnosis of AVNRT was confirmed in 412 pts, and RFC-guided ablation was attempted in 386 pts (age 13.0 ± 3.5 years). No permanent complications were observed. RFC application resulted in SP-ablation in 171/386 (44.3%) and in SP modulation in 208/386 (53.9%) children, whereas attempts for RFC treatment failed in 7 pts. Follow-up was completed for 396/412 patients (96.1%). Within a mean follow-up period of 54.9 ± 39.7 months, in 51/379 pts (13.5%) AVNRT recurrence was observed. The median time until tachycardia recurrence was 19.5 months. No difference for AVNRT recurrence was found comparing SP ablation versus SP modulation (p > 0.05), whereas the recurrence rate was significantly higher in patients with non-inducible SVT and therefore empiric SP treatment as compared to patients with inducible AVNRT (p = 0.01). RFC-guided ablation for AVNRT in children and adolescents is safe and leads to an acceptable long-term freedom from recurrences. SP modulation and SP ablation resulted in comparable acute and long-term success rates. Late AVNRT recurrences can occur even after years of freedom from tachycardia-related symptoms.

Clinical implications of atrial isomerism.

PubMed Central

Chiu, I S; How, S W; Wang, J K; Wu, M H; Chu, S H; Lue, H C; Hung, C R

1988-01-01

Right atrial isomerism or left atrial isomerism is frequently diagnosed as situs ambiguous without further discrimination of the specific morbid anatomy. Thirty six cases of right atrial isomerism and seven cases of left atrial isomerism were collected from the records and pathological museum at the National Taiwan University Hospital. There was a necropsy report for 18 cases. In all patients one or more of the following conditions was met: (a) isomeric bronchial anatomy, (b) echocardiographic and angiocardiographic evidence of isomerism, and (c) surgical or necropsy evidence of abnormal atrial anatomy. An anomalous pulmonary venous connection was present in 55% of patients with right atrial isomerism; in left atrial isomerism one case (14%) had a partial anomalous pulmonary venous connection. Forty per cent of cases of anomalous pulmonary venous connection with right atrial isomerism had obstruction. Six (86%) of seven cases with left atrial isomerism had an ambiguous biventricular atrioventricular connection. In contrast, univentricular atrioventricular connection (26 of 36, 72%) was significantly more common in right atrial isomerism. A common atrioventricular valve was the most frequent mode of connection in both forms. Two discrete atrioventricular valves were significantly more common in left atrial isomerism. Atrioventricular valve regurgitation was detected in 14 cases. Double outlet right ventricle was the most common type of ventriculoarterial connection. The most commonly cited causes of death after either palliative or definitive operation were undetected anomalous pulmonary venous connection, pulmonary venous stricture, and uncorrected atrioventricular valve or aortic regurgitation complicated by abnormal coagulation. Although the prognosis is poor, successful operation depends on knowledge of the precise anatomical arrangement associated with atrial isomerism. Images Fig 1 Fig 2 Fig 3 PMID:3408620

Challenges of univentricular physiology in heterotaxy.

PubMed

Jacobs, Marshall L; Mavroudis, Constantine

2011-04-01

Patients with heterotaxy syndrome exhibit an extensive constellation of congenital cardiac malformations, making these patients a challenging group to manage surgically. Many of these patients' hearts do not lend themselves to separation of the pulmonary and systemic circulations except by some modification of the Fontan procedure. Palliative procedures early in life are directed at creating a satisfactory balance of pulmonary and systemic blood flow and at the same time ensuring unobstructed pulmonary venous return. Early conversion from parallel pulmonary and systemic circulations to superior cavopulmonary connections is important, to reduce volume work of the systemic ventricle. Heterotaxy patients are generally considered a high-risk population with respect to eventual Fontan procedure. It is important to appreciate the unique and variable anatomy of the sinus node and conduction system and the potential for occult pulmonary venous obstruction, atrioventricular valve regurgitation, and recurrent cyanosis, which may be related to the development of pulmonary arteriovenous malformations.

Initial dynamics of the EKG during an electrical defibrillation of the heart

NASA Technical Reports Server (NTRS)

Bikov, I. I.; Chebotarov, Y. P.; Nikolaev, V. G.

1980-01-01

In tests on 11 mature dogs, immobilized by means of an automatic blocking and synchronization system, artefact free EKG were obtained, beginning 0.04-0.06 sec after passage of a defibrillating current. Different versions of the start of fibrillation were noted, in application of the defibrillating stimulus in the early phase of the cardiac cycle. A swinging phenomenon, increasing amplitude, of fibrillation was noted for 0.4-1.5 sec after delivery of a subthreshold stimulus. Conditions for a positive outcome of repeated defibrillation were found, and a relationship was noted between the configuration of the exciting process with respect to the lines of force of the defibrillating current and the defibrillation threshold. It was shown that the initial EKG dynamics after defibrillation is based on a gradual shift of the pacemaker from the myocardium of the ventricles to the sinus node, through phases of atrioventricular and atrial automatism.

A genome-wide association study to identify genomic modulators of rate control therapy in patients with atrial fibrillation.

PubMed

Kolek, Matthew J; Edwards, Todd L; Muhammad, Raafia; Balouch, Adnan; Shoemaker, M Benjamin; Blair, Marcia A; Kor, Kaylen C; Takahashi, Atsushi; Kubo, Michiaki; Roden, Dan M; Tanaka, Toshihiro; Darbar, Dawood

2014-08-15

For many patients with atrial fibrillation, ventricular rate control with atrioventricular (AV) nodal blockers is considered first-line therapy, although response to treatment is highly variable. Using an extreme phenotype of failure of rate control necessitating AV nodal ablation and pacemaker implantation, we conducted a genome-wide association study (GWAS) to identify genomic modulators of rate control therapy. Cases included 95 patients who failed rate control therapy. Controls (n = 190) achieved adequate rate control therapy with ≤2 AV nodal blockers using a conventional clinical definition. Genotyping was performed on the Illumina 610-Quad platform, and results were imputed to the 1000 Genomes reference haplotypes. A total of 554,041 single-nucleotide polymorphisms (SNPs) met criteria for minor allele frequency (>0.01), call rate (>95%), and quality control, and 6,055,224 SNPs were available after imputation. No SNP reached the canonical threshold for significance for GWAS of p <5 × 10(-8). Sixty-three SNPs with p <10(-5) at 6 genomic loci were genotyped in a validation cohort of 130 cases and 157 controls. These included 6q24.3 (near SAMD5/SASH1, p = 9.36 × 10(-8)), 4q12 (IGFBP7, p = 1.75 × 10(-7)), 6q22.33 (C6orf174, p = 4.86 × 10(-7)), 3p21.31 (CDCP1, p = 1.18 × 10(-6)), 12p12.1 (SOX5, p = 1.62 × 10(-6)), and 7p11 (LANCL2, p = 6.51 × 10(-6)). However, none of these were significant in the replication cohort or in a meta-analysis of both cohorts. In conclusion, we identified several potentially important genomic modulators of rate control therapy in atrial fibrillation, particularly SOX5, which was previously associated with heart rate at rest and PR interval. However, these failed to reach genome-wide significance. Copyright © 2014 Elsevier Inc. All rights reserved.

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

PubMed

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

2016-01-01

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

Extracorporeal membrane oxygenation in children with heart disease and down syndrome: a multicenter analysis.

PubMed

Gupta, Punkaj; Gossett, Jeffrey M; Rycus, Peter T; Prodhan, Parthak

2014-12-01

The data on the outcomes of children with heart disease and Down syndrome receiving extracorporeal membrane oxygenation (ECMO) for cardiac or respiratory failure are limited. This study aimed to evaluate morbidity and mortality associated with ECMO in children with Down syndrome and heart disease. Children younger than 18 years undergoing heart surgery and ECMO reported in the Extracorporeal Life Support Organization (ELSO) registry (1998-2011) were included in the study. The registry was queried for the following five heart defects: common atrioventricular (AV) canal, tetralogy of Fallot, truncus arteriosus, transposition of great vessels, and interrupted aortic arch. Data collection included patient characteristics, ECMO characteristics, and outcomes. The outcomes evaluated included mortality, ECMO duration, and length of hospital stay for patients with Down syndrome and those with no Down syndrome. The study enrolled 2,815 patients qualified for inclusion. Of these patients, 121 had Down syndrome, whereas 2,694 had no genetic syndrome and were included in the control group. The median age of the patients was 45 days (interquartile range [IQR] 9-192 days), and the median weight was 3.8 kg (IQR 3.0-6.1 kg). The most common cardiac defects in Down syndrome group were common AV canal (63 %) and tetralogy of Fallot (40 %). The Down syndrome group included older patients with greater body weight than the control group. The mortality rate was lower in the Down syndrome group than in the control group (44 vs. 56 %; p = 0.01). The duration of ECMO and length of hospital stay were similar in the two groups. The findings showed that ECMO can be used for children with heart disease and Down syndrome with good results. The outcomes were comparable between the children with Down syndrome and the children without Down syndrome.

Lacosamide cardiac safety: clinical trials in patients with partial-onset seizures.

PubMed

Rudd, G D; Haverkamp, W; Mason, J W; Wenger, T; Jay, G; Hebert, D; Doty, P; Horstmann, R

2015-11-01

To evaluate the cardiac safety of adjunctive lacosamide in a large pool of adults with partial-onset seizures (POS). Post-randomization changes from baseline for electrocardiographic (ECG) measurements, diagnostic findings, and relevant adverse events (AEs) were compared for pooled data from three randomized, placebo-controlled trials of adjunctive lacosamide for the treatment of POS. Lacosamide did not prolong the QTc interval or affect heart rate as determined by an analysis of data from patients randomized to lacosamide 200, 400, or 600 mg/day (n = 944) compared with placebo (n = 364). After 12-week maintenance treatment, mean changes from baseline for QRS duration were similar between the placebo and lacosamide 200 and 400 mg/day groups (0.0, -0.2, and 0.4 ms), but slightly increased for lacosamide 600 mg/day (2.3 ms). A small, dose-related mean increase in PR interval was observed (-0.3, 1.4, 4.4, and 6.6 ms for the placebo and lacosamide 200, 400, and 600 mg/day groups, respectively). First-degree atrioventricular (AV) block was reported as a non-serious AE in 0.0%, 0.7%, 0.2%, and 0.5% of patients in the same respective groups. Second- or higher degree AV block was not observed. There was no evidence of a PR-interval-related pharmacodynamic interaction of lacosamide with either carbamazepine or lamotrigine. Evaluation of the pooled cardiac safety data from patients with POS showed that adjunctive lacosamide at the maximum recommended dose (400 mg/day) was not clearly associated with any cardiac effect other than a small, dose-related increase in PR interval that had no evident symptomatic consequence. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Congenital heart defect causing mutation in Nkx2.5 displays in vivo functional deficit.

PubMed

Zakariyah, Abeer F; Rajgara, Rashida F; Veinot, John P; Skerjanc, Ilona S; Burgon, Patrick G

2017-04-01

The Nkx2.5 gene encodes a transcription factor that plays a critical role in heart development. In humans, heterozygous mutations in NKX2.5 result in congenital heart defects (CHDs). However, the molecular mechanisms by which these mutations cause the disease remain unknown. NKX2.5-R142C is a mutation that was reported to be associated with atrial septal defect (ASD) and atrioventricular (AV) block in 13-patients from one family. The R142C mutation is located within both the DNA-binding domain and the nuclear localization sequence of NKX2.5 protein. The pathogenesis of CHDs in humans with R142C point mutation is not well understood. To examine the functional deficit associated with this mutation in vivo, we generated and characterized a knock-in mouse that harbours the human mutation R142C. Systematic structural and functional examination of the embryonic, newborn, and adult mice revealed that the homozygous embryos Nkx2.5 R141C/R141C are developmentally arrested around E10.5 with delayed heart morphogenesis and downregulation of Nkx2.5 target genes, Anf, Mlc2v, Actc1 and Cx40. Histological examination of Nkx2.5 R141C/+ newborn hearts showed that 36% displayed ASD, with at least 80% 0f adult heterozygotes displaying a septal defect. Moreover, heterozygous Nkx2.5 R141C/+ newborn mice have downregulation of ion channel genes with 11/12 adult mice manifesting a prolonged PR interval that is indicative of 1st degree AV block. Collectively, the present study demonstrates that mice with the R141C point mutation in the Nkx2.5 allele phenocopies humans with the NKX2.5 R142C point mutation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Initial experience with mode switching in a dual sensor, dual chamber pacemaker in patients with paroxysmal atrial tachyarrhythmias.

PubMed

den Dulk, K; Dijkman, B; Pieterse, M; Wellens, H

1994-11-01

Mode switching algorithms have been developed to avoid tracking of atrial fibrillation (AF) or flutter (AFL) during DDD(R) pacing. Upon recognition of AF or AFL, the mode is switched to a nontracking, sensor driven mode. The Vitatron Diamond model 800 pacemaker does this on a beat-to-beat basis. Atrial events occurring within a "physiological range" (+/- 15 beats/min) calculated from a running average of the atrial rate are tracked. When atrial events are not tracked the escape interval is either determined by the sensor(s) or by a fallback algorithm thereby preventing large increases in V-V interval during mode switching. Loss of atrioventricular (AV) synchrony by atrial premature beats and after an episode of AF or AFL is prevented by atrial synchronization pulses (ASP), which are delivered after a safe interval (timed out from the sensed premature atrial event) has expired and before delivery of the next ventricular stimulus. We implanted 26 such devices in 18 men and 8 women with symptomatic second- or third-degree AV block and paroxysmal AF or AFL. Their ages ranged from 18-84 years (mean 60), and the follow-up ranged from 2-13 months (mean 8). During pacemaker check-up, exercise testing or 24-hour Holter monitoring one or more episodes of mode switching was documented in 8 patients. In these 8 patients a smooth transition (ventricular rate) from sinus rhythm to AF or AFL was documented on one or more occasions, without inappropriate increase in ventricular rate in the DDDR mode. None of the patients complained of palpitations.(ABSTRACT TRUNCATED AT 250 WORDS)

A null mutation of Hhex results in abnormal cardiac development, defective vasculogenesis and elevated Vegfa levels.

PubMed

Hallaq, Haifa; Pinter, Emese; Enciso, Josephine; McGrath, James; Zeiss, Caroline; Brueckner, Martina; Madri, Joseph; Jacobs, Harris C; Wilson, Christine M; Vasavada, Hemaxi; Jiang, Xiaobing; Bogue, Clifford W

2004-10-01

The homeobox gene Hhex has recently been shown to be essential for normal liver, thyroid and forebrain development. Hhex(-/-) mice die by mid-gestation (E14.5) and the cause of their early demise remains unclear. Because Hhex is expressed in the developing blood islands at E7.0 in the endothelium of the developing vasculature and heart at E9.0-9.5, and in the ventral foregut endoderm at E8.5-9.0, it has been postulated to play a critical role in heart and vascular development. We show here, for the first time, that a null mutation of Hhex results in striking abnormalities of cardiac and vascular development which include: (1) defective vasculogenesis, (2) hypoplasia of the right ventricle, (3) overabundant endocardial cushions accompanied by ventricular septal defects, outflow tract abnormalities and atrio-ventricular (AV) valve dysplasia and (4) aberrant development of the compact myocardium. The dramatic enlargement of the endocardial cushions in the absence of Hhex is due to decreased apoptosis and dysregulated epithelial-mesenchymal transformation (EMT). Interestingly, vascular endothelial growth factor A (Vegfa) levels in the hearts of Hhex(-/-) mice were elevated as much as three-fold between E9.5 and E11.5, and treatment of cultured Hhex(-/-) AV explants with truncated soluble Vegfa receptor 1, sFlt-1, an inhibitor of Vegf signaling, completely abolished the excessive epithelial-mesenchymal transformation seen in the absence of Hhex. Therefore, Hhex expression in the ventral foregut endoderm and/or the endothelium is necessary for normal cardiovascular development in vivo, and one function of Hhex is to repress Vegfa levels during development.

Electrophysiological properties of myocytes isolated from the mouse atrioventricular node: L-type ICa, IKr, If, and Na-Ca exchange.

PubMed

Choisy, Stéphanie C; Cheng, Hongwei; Orchard, Clive H; James, Andrew F; Hancox, Jules C

2015-11-01

The atrioventricular node (AVN) is a key component of the cardiac pacemaker-conduction system. This study investigated the electrophysiology of cells isolated from the AVN region of adult mouse hearts, and compared murine ionic current magnitude with that of cells from the more extensively studied rabbit AVN. Whole-cell patch-clamp recordings of ionic currents, and perforated-patch recordings of action potentials (APs), were made at 35-37°C. Hyperpolarizing voltage commands from -40 mV elicited a Ba(2+)-sensitive inward rectifier current that was small at diastolic potentials. Some cells (Type 1; 33.4 ± 2.2 pF; n = 19) lacked the pacemaker current, If, whilst others (Type 2; 34.2 ± 1.5 pF; n = 21) exhibited a clear If, which was larger than in rabbit AVN cells. On depolarization from -40 mV L-type Ca(2+) current, IC a,L, was elicited with a half maximal activation voltage (V0.5) of -7.6 ± 1.2 mV (n = 24). IC a,L density was smaller than in rabbit AVN cells. Rapid delayed rectifier (IK r) tail currents sensitive to E-4031 (5 μmol/L) were observed on repolarization to -40 mV, with an activation V0.5 of -10.7 ± 4.7 mV (n = 8). The IK r magnitude was similar in mouse and rabbit AVN. Under Na-Ca exchange selective conditions, mouse AVN cells exhibited 5 mmol/L Ni-sensitive exchange current that was inwardly directed negative to the holding potential (-40 mV). Spontaneous APs (5.2 ± 0.5 sec(-1); n = 6) exhibited an upstroke velocity of 37.7 ± 16.2 V/s and ceased following inhibition of sarcoplasmic reticulum Ca(2+) release by 1 μmol/L ryanodine, implicating intracellular Ca(2+) cycling in murine AVN cell electrogenesis. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Electrophysiological effects of desflurane in children with Wolff-Parkinson-White syndrome: a randomized crossover study.

PubMed

Hino, H; Oda, Y; Yoshida, Y; Suzuki, T; Shimada, M; Nishikawa, K

2018-02-01

We hypothesized that, compared with propofol, desflurane prolongs the antegrade accessory pathway effective refractory period (APERP) in children undergoing radiofrequency catheter ablation for Wolff-Parkinson-White (WPW) syndrome. In this randomized crossover study, children aged 4.1-16.1 years undergoing radiofrequency catheter ablation for WPW syndrome were randomly divided into four groups according to the concentration of desflurane and anesthetics used in the first and the second electrophysiological studies (EPS). After induction of general anesthesia with propofol and tracheal intubation, they received one of the following regimens: 0.5 minimum alveolar concentration (MAC) desflurane (first EPS) and propofol (second EPS) (Des0.5-Prop group, n = 8); propofol (first EPS) and 0.5 MAC desflurane (second EPS) (Prop-Des0.5 group, n = 9); 1 MAC desflurane (first EPS) and propofol (second EPS) (Des1.0-Prop group, n = 10); propofol (first EPS) and 1 MAC desflurane (second EPS) (Prop-Des1.0 group, n = 9). Radiofrequency catheter ablation was performed upon completion of EPS. Sample size was determined to detect a difference in the APERP. Desflurane at 1.0 MAC significantly prolonged the APERP compared with propofol, but did not affect the sinoatrial conduction time, atrio-His interval or atrioventricular node effective refractory period. Supraventricular tachycardia was induced in all children receiving propofol, but not induced in 1 and 4 children receiving 0.5 MAC and 1.0 MAC desflurane, respectively. Desflurane enhances the refractoriness and may block the electrical conduction of the atrioventricular accessory pathway, and is therefore not suitable for use in children undergoing radiofrequency catheter ablation for WPW syndrome. © 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Electrophysiologic profile and results of invasive risk stratification in asymptomatic children and adolescents with the Wolff-Parkinson-White electrocardiographic pattern.

PubMed

Kubuš, Peter; Vít, Pavel; Gebauer, Roman A; Materna, Ondřej; Janoušek, Jan

2014-04-01

Data on the results and clinical effect of an invasive risk stratification strategy in asymptomatic young patients with the Wolff-Parkinson-White electrocardiographic pattern are scarce. Eighty-five consecutive patients aged<18 years with a Wolff-Parkinson-White pattern and persistent preexcitation at maximum exercise undergoing invasive risk stratification were retrospectively studied. Adverse accessory pathway (AP) properties were defined according to currently consented criteria as any of the following: shortest preexcited RR interval during atrial fibrillation/rapid atrial pacing≤250 ms (or antegrade effective refractory period≤250 ms if shortest preexcited RR interval was not available) or inducible atrioventricular re-entrant tachycardia. Age at evaluation was median 14.9 years. Eighty-two patients had a structurally normal heart and 3 had hypertrophic cardiomyopathy. A single manifest AP was present in 80, 1 manifest and 1 concealed AP in 4, and 2 manifest APs in 1 patient. Adverse AP properties were present in 32 of 85 patients (37.6%) at baseline and in additional 16 of 44 (36.4%) after isoproterenol. Ablation was performed in 41 of these 48 patients. Ablation was deferred in the remaining 7 for pathway proximity to the atrioventricular node. In addition, 18 of the low-risk patients were ablated based on patient/parental decision. Adverse AP properties at baseline were exhibited by 37.6% of the evaluated patients with an asymptomatic Wolff-Parkinson-White preexcitation persisting at peak exercise. Isoproterenol challenge yielded additional 36.4% of those tested at higher risk. Ablation was performed in a total of 69.4% of patients subjected to invasive risk stratification.

Feasibility and safety of adenosine cardiovascular magnetic resonance in patients with MR conditional pacemaker systems at 1.5 Tesla.

PubMed

Klein-Wiele, Oliver; Garmer, Marietta; Urbien, Rhyan; Busch, Martin; Kara, Kaffer; Mateiescu, Serban; Grönemeyer, Dietrich; Schulte-Hermes, Michael; Garbrecht, Marc; Hailer, Birgit

2015-12-22

Cardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine. We retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement. Pacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p < 0.001), no bradycardia occurred. On the contrary in AV block heart rate remained constant; asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm. Adenosine stress CMR appears to be feasible and safe in patients with MR conditional pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR.

Atrioventricular Block Induced by Mad-Honey Intoxication

PubMed Central

Cagli, Kumral Ergun; Tufekcioglu, Omac; Sen, Nihat; Aras, Dursun; Topaloglu, Serkan; Basar, Nur; Pehlivan, Sevil

2009-01-01

An unusual type of food poisoning, mad-honey intoxication, can be observed in the Black Sea region of Turkey and various other parts of the world. It can occur after ingestion of grayanotoxin-contaminated honey produced from the nectar of Rhododendron ponticum and other plant species, chiefly of the Ericaceae and Sapindaceae families. Mad-honey intoxication can result in severe cardiac complications, such as complete atrioventricular block. The diagnosis is generally reached on the basis of the patient's history of honey intake. In this report, we describe the case of a patient who had mad-honey–related complete atrioventricular block; in this instance, the diagnosis was confirmed by a pollen analysis of the suspect honey. PMID:19693312

Sutureless Technique to Fix the Great Saphenous Vein along the Atrioventricular Groove Using Fibrin Glue in Off-Pump Coronary Artery Bypass Grafting.

PubMed

Ohira, Suguru; Doi, Kiyoshi; Yaku, Hitoshi

2016-04-05

We describe a simple method to fix the great saphenous vein graft (SVG) to the right coronary artery along the atrioventricular groove using fibrin glue in off-pump coronary artery bypass grafting (OPCAB). After completion of the proximal anastomosis, the SVG was placed along the atrioventricular groove to the acute margin. Fibrin glue was sprayed using pressurized carbon dioxide gas. A distal anastomosis was subsequently performed after rotating the heart to expose the posterior descending artery. It is a straightforward and reproducible technique to determine the optimal length of the SVG and prevent kinking or stretching of the graft, especially in OPCAB.

Clinical Assessment of Intraventricular Blood Transport in Patients Undergoing Cardiac Resynchronization Therapy

NASA Astrophysics Data System (ADS)

Rossini, Lorenzo; Martinez-Legazpi, P.; Benito, Y.; Perez Del Villar, C.; Gonzalez-Mansilla, A.; Barrio, A.; Yotti, R.; Kahn, A. M.; Shadden, S. C.; Fernandez-Aviles, F.; Bermejo, J.; Del Alamo, J. C.

2015-11-01

In the healthy heart, left ventricular (LV) filling generates flow patterns which have been proposed to optimize blood transport by coupling diastole and systole phases. We present a novel image-based method to assess how flow patterns influence LV blood transport in patients undergoing cardiac resynchronization therapy (CRT). Solving the advection equation with time-varying inflow boundary conditions allows to track the transport of blood entering the LV in the different filling waves, as well as the transport barriers which couple filling and ejection. The velocity fields were obtained using echocardiographic color Doppler velocimetry, which provides two-dimensional time-resolved flow maps in the apical long axis three-chamber view of the LV. We analyze flow transport in a group of patients with CRT devices as well as in healthy volunteers. In the patients under CRT, the device programming was varied to analyze flow transport under different values of the atrioventricular (AV) conduction delay and to model tachycardia. This analysis illustrates how CRT influences the transit of blood inside the LV, contributes to conserving kinetic energy and favors the generation of hemodynamic forces that accelerate blood in the direction of the LV outflow tract.

The use of non-invasive fetal electrocardiography in diagnosing second-degree fetal atrioventricular block.

PubMed

Lakhno, Igor; Behar, Joachim A; Oster, Julien; Shulgin, Vyacheslav; Ostras, Oleksii; Andreotti, Fernando

2017-01-01

Complete atrioventricular block in fetuses is known to be mostly associated with autoimmune disease and can be irreversible if no steroids treatment is provided. Conventional methods used in clinical practice for diagnosing fetal arrhythmia are limited since they do not reflect the primary electrophysiological conduction processes that take place in the myocardium. The non-invasive fetal electrocardiogram has the potential to better support fetal arrhythmias diagnosis through the continuous analysis of the beat to beat variation of the fetal heart rate and morphological analysis of the PQRST complex. We present two retrospective case reports on which atrioventricular block diagnosis could have been supported by the non-invasive fetal electrocardiogram. The two cases comprised a 22-year-old pregnant woman with the gestational age of 31 weeks and a 25-year-old pregnant woman with the gestational age of 41 weeks. Both women were admitted to the Department of Maternal and Fetal Medicine at the Kyiv and Kharkiv municipal perinatal clinics. Patients were observed using standard fetal monitoring methods as well as the non-invasive fetal electrocardiogram. The non-invasive fetal electrocardiographic recordings were analyzed retrospectively, where it is possible to identify the presence of the atrioventricular block. This study demonstrates, for the first time, the feasibility of the non-invasive fetal electrocardiogram as a supplementary method to diagnose of the fetal atrioventricular block. Combined with current fetal monitoring techniques, non-invasive fetal electrocardiography could support clinical decisions.

Atrioventricular valve repair in patients with functional single-ventricle physiology: impact of ventricular and valve function and morphology on survival and reintervention.

PubMed

Honjo, Osami; Atlin, Cori R; Mertens, Luc; Al-Radi, Osman O; Redington, Andrew N; Caldarone, Christopher A; Van Arsdell, Glen S

2011-08-01

This study was to determine whether atrioventricular valve repair modifies natural history of single-ventricle patients with atrioventricular valve insufficiency and to identify factors predicting survival and reintervention. Fifty-seven (13.5%) of 422 single-ventricle patients underwent atrioventricular valve repair. Valve morphology, regurgitation mechanism, and ventricular morphology and function were analyzed for effect on survival, transplant, and reintervention with multivariate logistic and Cox regression models. Comparative analysis used case-matched controls. Atrioventricular valve was tricuspid in 67% and common in 28%. Ventricular morphology was right in 83%. Regurgitation mechanisms were prolapse (n = 24, 46%), dysplasia (n = 18, 35%), annular dilatation (n = 8, 15%), and restriction or cleft (n = 2, 4%). Postrepair insufficiency was none or trivial in 14 (26%), mild in 33 (61%), and moderate in 7 (13%). Survival in repair group was lower than in matched controls (78.9% vs 92.7% at 1 year, 68.7% vs 90.6% at 3 years, P = .015). Patients with successful repair and normal ventricular function had equivalent survival to matched controls (P = .36). Independent predictors for death or transplant included increased indexed annular size (P = .05), increased cardiopulmonary bypass time (P = .04), and decreased postrepair ventricular function (P = .01). Ventricular dilation was a time-related factor for all events, including failed repair. Survival was lower in single-ventricle patients operated on for atrioventricular valve insufficiency than in case-matched controls. Patients with little postoperative residual regurgitation and preserved ventricular function had equivalent survival to controls. Lower grade ventricular function and ventricular dilation correlated with death and repair failure, suggesting that timing of intervention may affect outcome. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Usefulness of left ventricular inflow index to predict successful biventricular repair in right-dominant unbalanced atrioventricular canal.

PubMed

Szwast, Anita L; Marino, Bradley S; Rychik, Jack; Gaynor, James William; Spray, Thomas L; Cohen, Meryl S

2011-01-01

The outcome of biventricular (BV) repair for right-dominant unbalanced atrioventricular canal has remained poor, because it is difficult to predict left ventricular (LV) adequacy before surgery. Our aim was to determine whether preoperative echocardiographic parameters, specifically analysis of color inflow into the LV, would predict survival after BV repair in patients with right-dominant unbalanced atrioventricular canal. Subjects with right-dominant unbalanced atrioventricular canal diagnosed from 1994 to 2007 were included. The echocardiographic parameters were analyzed blinded to the palliation strategy and survival. The LV inflow index (LVII) was calculated as the secondary color inflow diameter indexed to the left atrioventricular valve (AVV) annulus diameter. Univariate analysis, survival analysis, and multivariate modeling with stepwise logistic regression were performed. Of the 45 subjects, 23 (51%) underwent single ventricle (SV) palliation and 22 (49%) underwent BV repair. Of the 23 who underwent SV palliation, 15 (65%) survived compared to 18 (82%) of 22 who underwent BV repair (p = 0.34). In the BV group, a greater LVII predicted survival (R2 = 0.46, p = 0.03). No subjects with a LVII <0.5 survived BV repair. Mortality in the BV group was associated with younger age at initial surgery (p <0.01) and abnormal left AVV morphology (p = 0.02). Of the BV subjects with a patent ductus arteriosus at the initial operation (n = 11), the nonsurvivors were more likely to have retrograde flow in the transverse arch (p <0.01). In the BV group, reoperation within 30 days of the initial repair was strongly associated with mortality (p <0.01). In conclusion, in cases of mild or moderate LV hypoplasia, a greater LVII predicted survival after BV repair in patients with right-dominant unbalanced atrioventricular canal. We propose incorporation of the LVII into the echocardiographic assessment of these patients. Copyright © 2011 Elsevier Inc. All rights reserved.

The angulation of the septal structures impacts ventricular imbalance in atrioventricular septal defects with a common atrioventricular junction.

PubMed

Ahmad, Zaheer; Lim, Zek; Roman, Kevin; Haw, Marcus; Anderson, Robert H; Vettukattil, Joseph

2016-02-01

Multiplanar re-formatting of full-volume three-dimensional echocardiography data sets offers new insights into the morphology of atrioventricular septal defects. We hypothesised that distortion of the alignment between the atrial and ventricular septums results in imbalanced venous return to the ventricles, with consequent proportional ventricular hypoplasia. A single observer evaluated 31 patients, with a mean age of 52.09 months, standard deviation of 55, and with a range from 2 to 264 months, with atrioventricular septal defects, of whom 17 were boys. Ventricular imbalance, observed in nine patients, was determined by two-dimensional assessment, and confirmed at surgical inspection in selected cases when a univentricular strategy was undertaken. Offline analysis using multiplanar re-formatting was performed. A line was drawn though the length of the ventricular septum and a second line along the plane of the atrial septum, taking the angle between these two lines as the atrioventricular septal angle. We compared the angle between 22 patients with adequately sized ventricles, and those with ventricular imbalance undergoing univentricular repair. In the 22 patients undergoing biventricular repair, the septal angle was 0 in 14 patients; the other eight patients having angles ranging from 1 to 36, with a mean angle of 7.4°, and standard deviation of 11.1°.The mean angle in the nine patients with ventricle imbalance was 28.6°, with a standard deviation of 3.04°, and with a range from 26 to 35°. Of those undergoing univentricular repair, two patients died, with angles of 26 and 30°, respectively. The atrioventricular septal angle derived via multiplanar formatting gives important information regarding the degree of ventricular hypoplasia and imbalance. When this angle is above 25°, patients are likely to have ventricular imbalance requiring univentricular repair.

Human embryonic and induced pluripotent stem cell-derived cardiomyocytes exhibit beat rate variability and power-law behavior.

PubMed

Mandel, Yael; Weissman, Amir; Schick, Revital; Barad, Lili; Novak, Atara; Meiry, Gideon; Goldberg, Stanislav; Lorber, Avraham; Rosen, Michael R; Itskovitz-Eldor, Joseph; Binah, Ofer

2012-02-21

The sinoatrial node is the main impulse-generating tissue in the heart. Atrioventricular conduction block and arrhythmias caused by sinoatrial node dysfunction are clinically important and generally treated with electronic pacemakers. Although an excellent solution, electronic pacemakers incorporate limitations that have stimulated research on biological pacing. To assess the suitability of potential biological pacemakers, we tested the hypothesis that the spontaneous electric activity of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) and induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) exhibit beat rate variability and power-law behavior comparable to those of human sinoatrial node. We recorded extracellular electrograms from hESC-CMs and iPSC-CMs under stable conditions for up to 15 days. The beat rate time series of the spontaneous activity were examined in terms of their power spectral density and additional methods derived from nonlinear dynamics. The major findings were that the mean beat rate of hESC-CMs and iPSC-CMs was stable throughout the 15-day follow-up period and was similar in both cell types, that hESC-CMs and iPSC-CMs exhibited intrinsic beat rate variability and fractal behavior, and that isoproterenol increased and carbamylcholine decreased the beating rate in both hESC-CMs and iPSC-CMs. This is the first study demonstrating that hESC-CMs and iPSC-CMs exhibit beat rate variability and power-law behavior as in humans, thus supporting the potential capability of these cell sources to serve as biological pacemakers. Our ability to generate sinoatrial-compatible spontaneous cardiomyocytes from the patient's own hair (via keratinocyte-derived iPSCs), thus eliminating the critical need for immunosuppression, renders these myocytes an attractive cell source as biological pacemakers.

Wireless visual sensor network resource allocation using cross-layer optimization

NASA Astrophysics Data System (ADS)

Bentley, Elizabeth S.; Matyjas, John D.; Medley, Michael J.; Kondi, Lisimachos P.

2009-01-01

In this paper, we propose an approach to manage network resources for a Direct Sequence Code Division Multiple Access (DS-CDMA) visual sensor network where nodes monitor scenes with varying levels of motion. It uses cross-layer optimization across the physical layer, the link layer and the application layer. Our technique simultaneously assigns a source coding rate, a channel coding rate, and a power level to all nodes in the network based on one of two criteria that maximize the quality of video of the entire network as a whole, subject to a constraint on the total chip rate. One criterion results in the minimal average end-to-end distortion amongst all nodes, while the other criterion minimizes the maximum distortion of the network. Our approach allows one to determine the capacity of the visual sensor network based on the number of nodes and the quality of video that must be transmitted. For bandwidth-limited applications, one can also determine the minimum bandwidth needed to accommodate a number of nodes with a specific target chip rate. Video captured by a sensor node camera is encoded and decoded using the H.264 video codec by a centralized control unit at the network layer. To reduce the computational complexity of the solution, Universal Rate-Distortion Characteristics (URDCs) are obtained experimentally to relate bit error probabilities to the distortion of corrupted video. Bit error rates are found first by using Viterbi's upper bounds on the bit error probability and second, by simulating nodes transmitting data spread by Total Square Correlation (TSC) codes over a Rayleigh-faded DS-CDMA channel and receiving that data using Auxiliary Vector (AV) filtering.

The electroneutral sodium/bicarbonate cotransporter containing an amino terminal 123-amino-acid cassette is expressed predominantly in the heart

PubMed Central

Cooper, Deborah S.; Lee, Hye Jeong; Yang, Han Soo; Kippen, Joseph; Yun, C. Chris; Choi, Inyeong

2006-01-01

Summary In this study, we examined the tissue-specific expression of two electroneutral Na/HCO3 cotransporter (NBCn1) variants that differ from each other by the presence of the N-terminal 123 amino acids (cassette II). A rat Northern blot with the probe to nucleotides encoding cassette II detected a 9 kb NBCn1 mRNA strongly in the heart and weakly in skeletal muscles, but absent from most of the tissues including kidney, brain, and pancreas. In the rat heart, PCR with primers flanking cassette II preferentially amplified a DNA fragment that lacked cassette II. However, in the human heart, PCR preferentially amplified a fragment that contained cassette II. This larger PCR product was found virtually in all regions of the human cardiovascular system with strong amplification in the apex, atrium, and atrioventricular nodes. These findings indicate that the variant containing cassette II is almost absent in tissues including brain, kidney, and pancreas, where NBCn1 has been extensively examined. PMID:16547769

Modeling our understanding of the His-Purkinje system.

PubMed

Vigmond, Edward J; Stuyvers, Bruno D

2016-01-01

The His-Purkinje System (HPS) is responsible for the rapid electric conduction in the ventricles. It relays electrical impulses from the atrioventricular node to the muscle cells and, thus, coordinates the contraction of ventricles in order to ensure proper cardiac pump function. The HPS has been implicated in the genesis of ventricular tachycardia and fibrillation as a source of ectopic beats, as well as forming distinct portions of reentry circuitry. Despite its importance, it remains much less well characterized, structurally and functionally, than the myocardium. Notably, important differences exist with regard to cell structure and electrophysiology, including ion channels, intracellular calcium handling, and gap junctions. Very few computational models address the HPS, and the majority of organ level modeling studies omit it. This review will provide an overview of our current knowledge of structure and function (including electrophysiology) of the HPS. We will review the most recent advances in modeling of the system from the single cell to the organ level, with considerations for relevant interspecies distinctions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Slow Pathway Radiofrequency Ablation Using Magnetic Navigation: A Description of Technique and Retrospective Case Analysis.

PubMed

Bhaskaran, Abhishek; Albarri, Maha; Ross, Neil; Al Raisi, Sara; Samanta, Rahul; Roode, Leonette; Nadri, Fazlur; Ng, Jeanette; Thomas, Stuart; Thiagalingam, Aravinda; Kovoor, Pramesh

2017-12-01

The Magnetic Navigation System (MNS) catheter was shown to be stable in the presence of significant cardiac wall motion and delivered more effective lesions compared to manual control. This stability could potentially make AV junctional re-entrant tachycardia (AVNRT) ablation safer. The aim of this study is to describe the method of mapping and ablation of AVNRT with MNS and 3-D electro-anatomical mapping system (CARTO, Biosense Webster, Diamond bar, CA, USA) anatomical mapping, with a view to improve the safety of ablation. The method of precise mapping and ablation with MNS is described. Consecutive AVNRT cases (n=30) from 2012 January to 2015 November, in which magnetic navigation was used, are analysed. Ablation was successful in 27 (90%) out of 30 patients. In three cases, ablation was abandoned due to the proximity of the three-dimensional His image to the potential ablation site. No complications, including AV nodal injury, occurred. The distance from the nearest His position to successful ablation site in both LAO and RAO projections of CARTO images was 26.4±8.8 and 27±7.7mm respectively. Only in two (9%) patients, ablation needed to be extended superior to the plane of coronary sinus ostium, towards the His bundle region, to achieve slow pathway modification. AVNRT ablation with MNS allows for accurate mapping of the AV node and stable ablation at a safe distance, which could help avoid AV nodal injury. We recommend this modality for younger patients with AVNRT. Copyright © 2017. Published by Elsevier B.V.

Do aggressive variants of papillary thyroid carcinoma have worse clinical outcome than classical papillary thyroid carcinoma?

PubMed

Song, Eyun; Jeon, Min Ji; Oh, Hye-Seon; Han, Minkyu; Lee, Yu-Mi; Kim, Tae Yong; Chung, Ki-Wook; Kim, Won Bae; Shong, Young-Kee; Song, Dong Eun; Kim, Won Gu

2018-06-06

Evidence for unfavorable outcomes of each type of aggressive variant papillary thyroid carcinoma (AV-PTC) is not clear because most previous studies are focused on tall cell variant (TCV) and did not control for other major confounding factors contributing to clinical outcomes. Retrospective cohort study. This study included 763 patients with classical PTC (cPTC) and 144 with AV-PTC, including TCV, columnar cell variant (CCV), and hobnail variants. Disease-free survival (DFS) and dynamic risk stratification (DRS) were compared after two-to-one propensity score matching by age, sex, tumor size, lymph node metastasis, and extrathyroidal extension. The AV-PTC group had significantly lower DFS rates than its matched cPTC group (HR=2.16, 95% CI 1.12-4.16, p=0.018). When TCV and CCV were evaluated separately, there was no significant differences in DFS and DRS between patients with TCV (n=121) and matched cPTC. However, CCV group (n=18) had significantly poorer DFS than matched cPTC group (HR=12.19, 95% CI 2.11-70.33, p=0.005). In DRS, there were significantly more patients with structural incomplete responses in CCV group compared by matched cPTC group (p=0.047). CCV was an independent risk factor for structural persistent/recurrent disease in multivariate analysis (HR, 4.28; 95% CI, 1.66-11.00, p=0.001). When other clinicopathological factors were similar, patients with TCV did not exhibit unfavorable clinical outcome whereas those with CCV had significantly poorer clinical outcome. Individualized therapeutic approach might be necessary for each type of AV-PTCs.

Atrioventricular valvular anomalies and their role in the etiopathogenesis of cardiorespiratory syndrome in farmed common foxes (Vulpes vulpes).

PubMed

Noszczyk-Nowak, Agnieszka; Piasecki, Tomasz; Cepiel, Alicja; Nowak, Marcin; Janus, Izabela; Pasławska, Urszula

2016-01-01

Cardiorespiratory syndrome of common foxes is associated with a mortality rate ranging from 2.1% to 20%. The aim of this study was to analyze the prevalence of cardiac abnormalities in common foxes (Vulpes vulpes) from Polish farms with a history of cardiorespiratory syndrome. The prevalence of cardiac abnormalities in common foxes from a Polish farm with a history of cardiorespiratory syndrome was assessed as well as morphological examination of 60 heart specimens from clinically healthy animals. In addition, 38 foxes were examined echocardiographically and subjected to postmortem examination. Atrioventricular valvular abnormalities were found in 57 out of the 98 (58%) analyzed hearts. The abnormalities of the mitral valve documented in more than 20% of the foxes in involved tendinous chords (completely lacking or shortened), papillary muscles and mitral cusps associated with both insufficiency and stenosis of the left atrioventricular orifice. Abnormalities of the tricuspid valve included significant shortening of the tendinous chords and thickening of the valve cusps with the impairment of their mobility. The results of the echocardiographic and postmortem examination were consistent in 79% of the cases. The specimens collected from animals with and without atrioventricular valvular anomalies did not differ significantly in terms of cardiomyocyte width, number of inflammatory cells, adipose tissue content and presence of polychromatic cardiomyocytes. Congenital atrioventricular valvular defects may be involved in the etiology of cardiorespiratory syndrome in common foxes, and echocardiography can be used as a measure of stock's health and a criterion for selection for mating.

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

PubMed

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

1996-12-01

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

Conduction Abnormalities and Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement Using the Repositionable LOTUS Device: The United Kingdom Experience.

PubMed

Rampat, Rajiv; Khawaja, M Zeeshan; Hilling-Smith, Roland; Byrne, Jonathan; MacCarthy, Philip; Blackman, Daniel J; Krishnamurthy, Arvindra; Gunarathne, Ashan; Kovac, Jan; Banning, Adrian; Kharbanda, Raj; Firoozi, Sami; Brecker, Stephen; Redwood, Simon; Bapat, Vinayak; Mullen, Michael; Aggarwal, Suneil; Manoharan, Ganesh; Spence, Mark S; Khogali, Saib; Dooley, Maureen; Cockburn, James; de Belder, Adam; Trivedi, Uday; Hildick-Smith, David

2017-06-26

The authors report the incidence of pacemaker implantation up to hospital discharge and the factors influencing pacing rate following implantation of the LOTUS bioprosthesis (Boston Scientific, Natick, Massachusetts) in the United Kingdom. Transcatheter aortic valve replacement (TAVR) is associated with a significant need for permanent pacemaker implantation. Pacing rates vary according to the device used. The REPRISE II (Repositionable Percutaneous Replacement of Stenotic Aortic Valve Through Implantation of Lotus Valve System) trial reported a pacing rate of 29% at 30 days after implantation of the LOTUS device. Data were collected retrospectively on 228 patients who had the LOTUS device implanted between March 2013 and February 2015 across 10 centers in the United Kingdom. Twenty-seven patients (12%) had pacemakers implanted pre-procedure and were excluded from the analysis. Patients were aged 81.2 ± 7.7 years; 50.7% were male. The mean pre-procedural QRS duration was 101.7 ± 20.4 ms. More than one-half of the cohort (n = 111, 55%) developed new left bundle branch block (LBBB) following the procedure. Permanent pacemakers were implanted in 64 patients (32%) with a median time to insertion of 3.0 ± 3.4 days. Chief indications for pacing were atrioventricular (AV) block (n = 46, 72%), or LBBB with 1st degree AV block (n = 11, 17%). Amongst those who received a pacemaker following TAVR the pre-procedural electrocardiogram findings included: No conduction disturbance (n = 41, 64%); 1st degree AV block (n = 10, 16%); right bundle branch block (n = 6, 9%) and LBBB (n = 5, 8%). LBBB (but not permanent pacemaker) occurred more frequently in patients who had balloon aortic valvuloplasty before TAVR (odds ratio [OR]: 1.25; p = 0.03). Pre-procedural conduction abnormality (composite of 1st degree AV block, hemiblock, right bundle branch block, LBBB) was independently associated with the need for permanent pacemaker (OR: 2.54; p = 0.048). The absence of aortic valve calcification was also associated with a higher pacing rate (OR: 0.55; p = 0.031). Multivariate regression analysis did not show an independent association between depth of implant, valve oversizing, balloon post-dilatation, and the need for pacing post-procedure. Following implantation of the repositionable LOTUS valve, 55% of patients developed LBBB and 32% of patients required a pacemaker during their index hospital admission. Patients with pre-procedural conduction disturbance and non-calcified aortic valves were more likely to need pacing. No other anatomic features were identified with increased pacing requirement with the LOTUS device. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Cleft closure and undersizing annuloplasty improve mitral repair in atrioventricular canal defects

PubMed Central

Padala, Muralidhar; Vasilyev, Nikolay V.; Owen, James W.; Jimenez, Jorge H.; Dasi, Lakshmi P.; del Nido, Pedro J.; Yoganathan, Ajit P.

2009-01-01

Objective Reoperation rates to correct left atrioventricular valve regurgitation after primary repair of atrioventricular canal defects remain relatively high. The causes of valvular regurgitation are likely multifactorial, and simple cleft closure is often insufficient to prevent recurrence. Methods To elucidate the mechanisms leading to regurgitation, we conducted hemodynamic studies using isolated native mitral valves. Anatomy of these valves was altered to mimic atrioventricular canal type valves and studied under pediatric hemodynamic conditions. The impact of subvalvular geometry, cleft closure, annular dilatation, and annular undersizing on regurgitation were investigated. Results Papillary muscle position did not have a significant effect on regurgitation. Cleft closure had a significant impact on valvular competence, with reduction in regurgitation volume with increased cleft closure. Regurgitation volume decreased from 12.5 ± 2.4 mL/beat for an open cleft to 4.9 ± 1.9 mL/beat for a partially closed cleft and to 1.4 ± 1.6 mL/beat when the cleft was completely closed. Annular dilatation had a significant impact on regurgitation even after cleft closure. A 40% increase in annular size increased regurgitation by 59% for a partially closed cleft and by 84% for a fully closed cleft. Reducing the annular size by 20% from the physiologic level decreased the regurgitation volume by 12% for a fully open cleft and by 58% for the partially closed cleft case. Conclusions Annular dilatation after primary repair has a potentially significant role in the recurrence of atrioventricular valve regurgitation. Reducing the annular size and restricting dilatation as an adjunct to cleft closure is a promising surgical approach in such valve anatomies. PMID:19026810

Left Ventricular Reverse Remodeling With Biventricular Versus Right Ventricular Pacing in Patients With Atrioventricular Block and Heart Failure in the BLOCK HF Trial.

PubMed

St John Sutton, Martin; Plappert, Ted; Adamson, Philip B; Li, Pei; Christman, Shelly A; Chung, Eugene S; Curtis, Anne B

2015-05-01

Biventricular pacing in heart failure (HF) improves survival, relieves symptoms, and attenuates left ventricular (LV) remodeling. However, little is known about biventricular pacing in HF patients with atrioventricular block because they are typically excluded from biventricular trials. The Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) trial randomized patients with atrioventricular block, New York Heart Association symptom classes I to III HF, and LV ejection fraction ≤50% to biventricular or right ventricular pacing. Doppler echocardiograms were obtained at randomization (after 30 to 60 days of right ventricular pacing postimplant) and every 6 months through 24 months. Data analysis comparing changes in 10 prespecified echo parameters over time was conducted using a Bayesian design. LV end systolic volume index was also evaluated as a predictor of mortality/morbidity. Of 691 randomized subjects, 624 had paired Doppler echocardiogram data for ≥1 analyses at 6, 12, 18, or 24 months. Biventricular pacing significantly reduced LV volume indices and intraventricular mechanical delay, and improved LV ejection fraction, consistent with LV reverse remodeling. These parameters showed little change with right ventricular pacing alone, indicating no systematic reverse remodeling with right ventricular pacing. LV end systolic volume index was predictive of mortality/morbidity; the estimated risk increased up to 1% for every 1 mL/m(2) increase in LV end systolic volume index. LV end systolic volume index is a significant predictor of mortality/morbidity in this population. Cardiac structure and function are improved with biventricular pacing for patients with atrioventricular block and LV systolic dysfunction. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00267098. © 2015 American Heart Association, Inc.

Echocardiographic definition and surgical decision-making in unbalanced atrioventricular septal defect: a Congenital Heart Surgeons' Society multiinstitutional study.

PubMed

Jegatheeswaran, Anusha; Pizarro, Christian; Caldarone, Christopher A; Cohen, Meryl S; Baffa, Jeanne M; Gremmels, David B; Mertens, Luc; Morell, Victor O; Williams, William G; Blackstone, Eugene H; McCrindle, Brian W; Overman, David M

2010-09-14

Although identification of unbalanced atrioventricular septal defect (AVSD) is obvious when extreme, exact criteria to define the limits of unbalanced are not available. We sought to validate an atrioventricular valve index (AVVI) (left atrioventricular valve area/total atrioventricular valve area, centimeters squared) as a discriminator of balanced and unbalanced forms of complete AVSD and to characterize the association of AVVI with surgical strategies and outcomes. Diagnostic echocardiograms and hospital records of 356 infants with complete AVSD at 4 Congenital Heart Surgeons' Society (CHSS) institutions (2000-2006) were reviewed and AVVI measured (n=315). Patients were classified as unbalanced if AVVI≤0.4 (right dominant) or ≥0.6 (left dominant). Surgical strategy and outcomes were examined across the range of AVVI. Competing risks analysis until the time of commitment to a surgical strategy examined 4 end states: biventricular repair (BVR), univentricular repair (UVR), pulmonary artery banding (PAB), and death before surgery. A prediction nomogram for surgical strategy based on AVVI was developed. The majority of patients had balanced AVSD (0.4

Radiofrequency ablation versus cryoablation for atrioventricular nodal re-entrant tachycardia in children: a value comparison.

PubMed

Oster, Matthew E; Yang, Zhou; Stewart-Huey, Kay; Glanville, Michelle; Porter, Arlene; Campbell, Robert; Webb, Brad; Strieper, Margaret

2017-03-01

It is unclear whether cryoablation or radiofrequency ablation offers better value for treating atrioventricular nodal re-entrant tachycardia in children. We aimed to compare the value of these procedures for treating atrioventricular nodal re-entrant tachycardia in children, with value being outcomes relative to costs. We performed a retrospective cohort study of all atrioventricular nodal re-entrant tachycardia ablations for children (age⩽18 years) from July, 2009 to June, 2011 at our institution. Costs included fixed costs, miscellaneous hospital costs, and labour costs, and key outcomes were acute and long-term success (6 months) of the ablations. We conducted T-tests and regression analyses to investigate the associations between the ablation procedure type and the cost and success of the ablations. Of 96 unique cases performed by three paediatric electrophysiologists, 48 were cryoablation only, 42 radiofrequency ablation only, and six were a combination. Acute success was 100% for the cryoablation only and radiofrequency ablation only cases and 83% for the combination cases. There were no notable adverse events. The average total cost was $9636 for cryoablation cases, $9708 for radiofrequency ablation cases, and $10,967 for combination cases (p=0.51 for cryoablation only versus radiofrequency ablation only). The long-term success rate was 79.1% for cryoablation only, 92.8% for radiofrequency ablation only, and 66.7% for the combination (p=0.01 for cryoablation only versus radiofrequency ablation only), but long-term success varied notably by provider. Cryoablation and radiofrequency ablation offer similar value in the short term for the treatment of atrioventricular nodal re-entrant tachycardia in children. Differences in long-term success may vary substantially by physician, and thus may lead to differences in long-term value.

Upgrading from VVI to DDD pacing Mode during elective replacement of pulse generator: a comparative clinical-functional analysis.

PubMed

Teno, Luiz Antonio Castilho; Costa, Roberto; Martinelli Filho, Martino; Castilho, Fabian Cecchi Teno; Ruiz, Ivan

2007-02-01

Evaluate the clinical and functional behavior of the ventricular and atrioventricular stimulation modes in the elective replacement of pulse generator in patients with chagasic cardiopathy and atrioventricular block. Twenty-seven patients under ventricular and atrioventricular stimulation were comparatively evaluated at the beginning of the study, and alternately in ventricular and atrioventricular modes in two 90-day phases, with regard to: the clinical behavior evaluated according to quality of life and functional class, and the functional behavior evaluated by transthoracic echocardiography and the six-minute walk test. The statistical analysis was performed with patients at baseline, and under ventricular and atrioventricular modes, using the chi-square test and the repeated measures analysis of variance, and taking into consideration a 0.05 level of significance. The mean quality-of-life scores were: functional capacity (VVI 71.3+/-18.2 , DDD 69.3+/-20.4); overall health status (VVI 68.1+/-21.8, DDD 69.4+/-19.4) and vitality (VVI 64.8+/-24.6 , DDD 67.6+/-25.5); on echocardiography: LVEF (VVI 52.5+/-12.8 , DDD 51.8+/-14.9), LVDD (VVI 53.0+/-7.7 , DDD 42.4+/-7.8), LA (VVI 38.6+/-5.4 DDD 38.5+/-5.1), and in the six-minute walk test: distance walked (VVI 463.4+/-84.7, DDD 462.6+/-63.4). There were four cases of complications, three of them associated with the change in stimulation mode. This study showed no differences between the two stimulation modes in the clinical behavior assessed by quality of life and functional class, and in the functional behavior, evaluated according to the ecochardiographic findings and the six-minute walk test.

Overlapping and differential localization of Bmp-2, Bmp-4, Msx-2 and apoptosis in the endocardial cushion and adjacent tissues of the developing mouse heart.

PubMed

Abdelwahid, E; Rice, D; Pelliniemi, L J; Jokinen, E

2001-07-01

The bone morphogenetic proteins BMP-2 and BMP-4 and the homeobox gene MSX-2 are required for normal development of many embryonic tissues. To elucidate their possible roles during the remodeling of the tubular heart into a fully septated four-chambered heart, we have localized the mRNA of Bmp-2, Bmp-4, Msx-2 and apoptotic cells in the developing mouse heart from embryonic day (E)11 to E17. mRNA was localized by in situ hybridization, and apoptotic cells by TUNEL (TDT-mediated dUTP-biotin nick end-labeling) as well as by transmission electron microscopy. By analyzing adjacent serial sections, we demonstrated that the expression of Msx-2 and Bmp-2 strikingly overlapped in the atrioventricular canal myocardium, in the atrioventricular junctional myocardium, and in the maturing myocardium of the atrioventricular valves. Bmp-4 was expressed in the outflow tract myocardium and in the endocardial cushion of the outflow tract ridges from E12 to E14. Msx-2 appeared in the mesenchyme of the atrioventricular endocardial cushion from E11 to E14, while Bmp-2 and Bmp-4 were detected between E11 and E14. Apoptotic cells were also detected in the mesenchyme of the endocardial cushion between E12 and E14. Our results suggest that BMP-2 and MSX-2 are tightly linked to the formation of the atrioventricular junction and valves and that BMP-4 is involved in the development of the outflow tract myocardium and of the endocardial cushion. In addition, BMP-2, BMP-4 and MSX-2 and apoptosis seem to be associated with differentiation of the endocardial cushion.

Simultaneous conduction over the fast and slow pathways during induction of atrioventricular nodal reentrant arrhythmia with a rate of less than 100 bpm and infra-His block after radiofrequency ablation of the slow pathway.

PubMed

Amasyalı, Basri; Köktürk, Bülent; Otomo, Kiyoshi; Köse, Sedat

2011-04-01

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of paroxysmal regular supraventricular tachycardia in adults. It is typically induced with an anterograde block over the fast pathway (FP) and conduction over the slow pathway (SP), with subsequent retrograde conduction over the FP. Rarely, a simultaneous conduction of a premature atrial complex occurs over the FP and SP to induce AVNRT and is called "one for two phenomenon". We present a 46-year-old woman with atrioventricular nodal rhythm with a rate of 95 beats per minute with distinct electrophysiological characteristics showing simultaneous conduction over the FP and SP during induction of tachycardia and an infra-His block after radiofrequency ablation of the SP.

Biological Glue Application in Repair of Atrioventricular Groove Rupture: A Case Report

PubMed Central

Durukan, Ahmet Baris; Serter, Fatih Tanzer; Gurbuz, Hasan Alper; Tavlasoglu, Murat; Ucar, Halil Ibrahim; Yorgancioglu, Cem

2014-01-01

Abstract Atrioventricular groove rupture is a rare, albeit mortal, complication following mitral valve surgery. Avoidance is the best strategy but it cannot fully prevent the occurrence of this complication. Several repair techniques have been described with varying success rates; however, the rarity of the complication precludes consensus about the safest technique. Here we report two cases of posterior atrioventricular groove rupture. Both cases were diagnosed immediately after the cessation of cardiopulmonary bypass. Repair was performed successfully with a technique involving the use of biological glue. The postoperative course was uneventful for both of them. Both cases are well with normally functioning mitral prostheses; one with a follow-up time of 5.5 years and the other 10 months. We believe that the glue provides additional hemostasis and support to the repaired area. PMID:25870633

T-cell phenotypes in bronchoalveolar lavage fluid, blood and lymph nodes in pulmonary sarcoidosis--indication for an airborne antigen as the triggering factor in sarcoidosis.

PubMed

Darlington, P; Haugom-Olsen, H; von Sivers, K; Wahlström, J; Runold, M; Svjatoha, V; Porwit, A; Eklund, A; Grunewald, J

2012-11-01

An increased percentage of CD4+ T cells is usually observed in bronchoalveolar lavage fluid (BALF) from patients with sarcoidosis. In HLA-DRB1*03-positive patients, such T cells express the T-cell receptor (TCR) AV2S3+ gene segment. It is not known whether cells found in BALF reflect those in enlarged regional lymph nodes (LNs). Therefore, the aim of this study was to compare T-cell phenotypes in BALF, blood and mediastinal LNs. Fifteen patients underwent clinical investigation including bronchoscopy with bronchoalveolar lavage. Blood samples were drawn, and endoscopic ultrasound-guided fine-needle aspiration of enlarged mediastinal LNs was performed via the oesophagus. T cells from all three compartments were analysed by flow cytometry for markers of activity, differentiation and T regulatory function. The CD4/CD8 ratio was significantly higher in BALF compared with regional LNs and was also significantly higher in LNs than in blood. The CD4+ T cells were recently activated and more differentiated in BALF than in blood and LNs. There was an accumulation of T regulatory cells (FOXP3+) in LNs and a correlation between high levels of FOXP3+ cells in BALF and in LNs. In HLA-DRB1*03-positive patients, TCR AV2S3+ CD4+ T cells were predominantly localized within BALF. The CD4+ T-cell phenotype in BALF indicates an active ongoing specific immune response primarily localized to the alveolar space. © 2012 The Association for the Publication of the Journal of Internal Medicine.

A simultaneous multichannel monophasic action potential electrode array for in vivo epicardial repolarization mapping.

PubMed

Sahakian, A V; Peterson, M S; Shkurovich, S; Hamer, M; Votapka, T; Ji, T; Swiryn, S

2001-03-01

While the recording of extracellular monophasic action potentials (MAPs) from single epicardial or endocardial sites has been performed for over a century, we are unaware of any previous successful attempt to record MAPs simultaneously from a large number of sites in vivo. We report here the design and validation of an array of MAP electrodes which records both depolarization and repolarization simultaneously at up to 16 epicardial sites in a square array on the heart in vivo. The array consists of 16 sintered Ag-AgCl electrodes mounted in a common housing with individual suspensions allowing each electrode to exert a controlled pressure on the epicardial surface. The electrodes are arranged in a square array, with each quadrant of four having an additional recessed sintered Ag-AgCl reference electrode at its center. A saline-soaked sponge establishes ionic contact between the reference electrodes and the tissue. The array was tested on six anesthetized open-chested pigs. Simultaneous diagnostic-quality MAP recordings were obtained from up to 13 out of 16 ventricular sites. Ventricular MAPs had amplitudes of 10-40 mV with uniform morphologies and stable baselines for up to 30 min. MAP duration at 90% repolarization was measured and shown to vary as expected with cycle length during sustained pacing. The relationship between MAP duration and effective refractory period was also confirmed. The ability of the array to detect local differences in repolarization was tested in two ways. Placement of the array straddling the atrioventricular (AV) junction yielded simultaneous atrial or ventricular recordings at corresponding sites during 1:1 and 2:1 AV conduction. Localized ischemia via constriction of a coronary artery branch resulted in shortening of the repolarization phase at the ischemic, but not the nonischemic, sites. In conclusion, these results indicate that the simultaneous multichannel MAP electrode array is a viable method for in vivo epicardial repolarization mapping. The array has the potential to be expanded to increase the number of sites and spatial resolution.

An observational study of the association among interatrial adiposity by computed tomography measure, insulin resistance, and left atrial electromechanical disturbances in heart failure.

PubMed

Hung, Chung-Lieh; Yun, Chun-Ho; Lai, Yau-Huei; Sung, Kuo-Tzu; Bezerra, Hiram G; Kuo, Jen-Yuan; Hou, Charles Jia-Yin; Chao, Tze-Fan; Bulwer, Bernard E; Yeh, Hung-I; Shih, Shou-Chuan; Lin, Shing-Jong; Cury, Ricardo C

2016-06-01

Excessive visceral adiposity, hypothesized to be a key mediator in metabolic derangements, has recently been shown to exert toxic effects on cardiac structure and function. Data regarding the mechanistic link between regional adiposity, left atrial (LA) electromechanical remodeling, and heart failure with preserved ejection fraction (HFpEF) have been lacking.Various visceral adiposity measures, including pericardial fat (PCF), thoracic periaortic (TAT) fat, regional inter-atrial fat (IAF), and atrioventricular groove fat (AV Groove Fat), were assessed by multidetector computed tomography in 2 study cohorts (an annual health survey cohort and an outpatient cohort). We related such measures to cardiometabolic profiles in health survey cohort and LA electromechanical indices in our outpatient cohort, with Cox proportional hazards performed to examine the temporal trends of heart failure (HF).In our annual health survey cohort (n = 362), all 4 adiposity measures were positively related to unfavorable anthropometrics and systemic inflammation (high-sensitivity C-reactive protein) (all P < 0.05). In addition, both greater IAF and AV Groove Fat were positively associated with higher fasting glucose, HbA1c levels, and insulin resistance (all P < 0.05). In the outpatient cohort, the HFpEF group demonstrated the greatest adiposity measures, with greater IAF (≥8.2 mm, hazard ratio: 4.11, 95% confidence interval: 1.50-11.32) associated with reduced LA strain (ß-coef: -0.28), higher LA stiffness (ß-coef: 0.23), and longer P wave duration (ß-coef: 0.23) in multivariate models (all P < 0.05), and further related to higher HF hospitalization during follow-up.We therefore propose a possible pathophysiologic link among greater visceral adiposity, systemic inflammation, cardiometabolic risks, and HFpEF. Regional adiposity, especially IAF, was tightly linked to altered LA electromechanical properties and likely plays a key role in HF prognosis.

Hydraulic forces contribute to left ventricular diastolic filling

PubMed Central

Maksuti, Elira; Carlsson, Marcus; Arheden, Håkan; Kovács, Sándor J.; Broomé, Michael; Ugander, Martin

2017-01-01

Myocardial active relaxation and restoring forces are known determinants of left ventricular (LV) diastolic function. We hypothesize the existence of an additional mechanism involved in LV filling, namely, a hydraulic force contributing to the longitudinal motion of the atrioventricular (AV) plane. A prerequisite for the presence of a net hydraulic force during diastole is that the atrial short-axis area (ASA) is smaller than the ventricular short-axis area (VSA). We aimed (a) to illustrate this mechanism in an analogous physical model, (b) to measure the ASA and VSA throughout the cardiac cycle in healthy volunteers using cardiovascular magnetic resonance imaging, and (c) to calculate the magnitude of the hydraulic force. The physical model illustrated that the anatomical difference between ASA and VSA provides the basis for generating a hydraulic force during diastole. In volunteers, VSA was greater than ASA during 75–100% of diastole. The hydraulic force was estimated to be 10–60% of the peak driving force of LV filling (1–3 N vs 5–10 N). Hydraulic forces are a consequence of left heart anatomy and aid LV diastolic filling. These findings suggest that the relationship between ASA and VSA, and the associated hydraulic force, should be considered when characterizing diastolic function and dysfunction. PMID:28256604

Effect of right ventricular pacing on cardiac apex rotation assessed by a gyroscopic sensor.

PubMed

Marcelli, Emanuela; Cercenelli, Laura; Parlapiano, Mario; Fumero, Roberto; Bagnoli, Paola; Costantino, Maria Laura; Plicchi, Gianni

2007-01-01

To quantify cardiac apex rotation (CAR), the authors recently proposed the use of a Coriolis force sensor (gyroscope) as an alternative to other complex techniques. The aim of this study was to evaluate the effects of right ventricular (RV) pacing on CAR. A sheep heart was initially paced from the right atrium to induce a normal activation sequence at a fixed heart rate (AAI mode) and then an atrioventricular pacing was performed (DOO mode, AV delay = 60 ms). A small gyroscope was epicardially glued on the cardiac apex to measure the angular velocity (Ang V). From AAI to DOO pacing mode, an increase (+9.2%, p < 0.05) of the maximum systolic twisting velocity (Ang VMAX) and a marked decrease (-19.9%, p < 0.05) of the maximum diastolic untwisting velocity (Ang VMIN) resulted. RV pacing had negligible effects (-3.1%, p = 0.09) on the maximum angle of CAR, obtained by integrating Ang V. The hemodynamic parameters of systolic (LVdP/dtMAX) and diastolic (LVdP/dtMIN) cardiac function showed slight variations (-3.8%, p < 0.05 and +3.9%, p < 0.05, respectively). Results suggest that cardiac dyssynchrony induced by RV pacing can alter the normal physiological ventricular twist patterns, particularly affecting diastolic untwisting velocity.

Evaluation and management of bradycardia in neonates and children.

PubMed

Baruteau, Alban-Elouen; Perry, James C; Sanatani, Shubhayan; Horie, Minoru; Dubin, Anne M

2016-02-01

Heart rate is commonly used in pediatric early warning scores. Age-related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiogram features that differ from adults and vary with age. Bradycardia is defined as a heart rate below the lowest normal value for age. Pediatric bradycardia most commonly manifests as sinus bradycardia, junctional bradycardia, or atrioventricular block. As a result of several different etiologies, it may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited sinus node dysfunction or progressive cardiac conduction disorders. Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause. Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia. The simplest aspect of severe bradycardia management is reflected in the Pediatric and Advanced Life Support (PALS) guidelines. Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current practice for evaluation and management of bradycardia in neonates and children. Bradycardia is defined as a heart rate below the lowest normal value for age. Age related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiogram features that differ from adults and vary with age. Pediatric bradycardia most commonly manifests as sinus bradycardia, junctional bradycardia, or atrioventricular block. Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause. Bradycardia may occur in a structurally normal heart or in association with congenital heart disease. Genetic variants in multiple genes have been described. Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia. Early diagnosis and appropriate management are critical in order to prevent sudden death.

Incidence and Time Course for Developing Heart Failure With High-Burden Right Ventricular Pacing.

PubMed

Merchant, Faisal M; Hoskins, Michael H; Musat, Dan L; Prillinger, Julie B; Roberts, Gregory J; Nabutovsky, Yelena; Mittal, Suneet

2017-06-01

Although right ventricular pacing can contribute to cardiomyopathy, the impact of complete atrioventricular block (cAVB) on heart failure (HF) development in pacemaker patients has not been well characterized. We evaluated the incidence and time course for developing HF after pacemaker implantation for cAVB. A MarketScan database identified patients undergoing dual-chamber pacemaker implantation from 2008 to 2014. Patients with cAVB were identified by an atrioventricular node ablation or diagnosis of third-degree AVB. Patients with ≥1 year of continuous MarketScan enrollment before and after implant and without a previous diagnosis of HF were dichotomized into those with cAVB and without AVB. The primary end point was new HF assessed over acute (0-6 months) and chronic (6 months to 4 years) phases post-pacemaker implantation. The cohort included 6994 cAVB patients and 14 208 patients without AVB, followed for 2.35 years (interquartile range, 1.62-3.39 years). After adjustment for baseline covariates, patients with cAVB experienced an increased risk of new-onset HF in the acute phase (hazard ratio, 1.62; 95% confidence interval, 1.48-1.79; P <0.001). Although the risk of HF remained elevated among those with cAVB in the chronic phase, the effect was attenuated (hazard ratio, 1.16; 95% confidence interval, 1.08-1.25; P <0.001). After pacemaker implantation, younger patients (≤55 years of age) and those with an antecedent history of atrial fibrillation experienced the highest risk of HF associated with cAVB. Patients with a diagnosis of cAVB, and thus presumed to have a higher burden of right ventricular pacing, experienced an increased risk of new-onset HF after pacemaker implantation compared with those without AVB. Better tools are needed to identify patients at high risk of developing HF in the setting of right ventricular pacing and to determine whether these patients benefit from upfront biventricular pacing. © 2017 American Heart Association, Inc.

Echocardiographic characteristics of the criss-cross heart.

PubMed

Yang, Ya-Li; Wang, Xin-Fang; Cheng, Tsung O; Xie, Ming-Xing; Lü, Qing; He, Lin; Lu, Xiao-Fang; Wang, Jing; Li, Ling; Anderson, Robert H

2010-04-15

To assess the ultrasonic characteristics of the criss-cross heart, and explore the value of echocardiography in the diagnosis of this rare congenital cardiac defect. We reviewed the echocardiographic findings in 4 patients having criss-crossed atrioventricular connections at our hospital, and compared the findings with observations at surgery in 3 of the patients. In all 4 patients, there was usual atrial arrangement, right hand ventricular topology, and concordant atrioventricular connections. The inlet components of the ventricular mass, however, crossed such that the apical component of the morphologically right ventricle was situated anteriorly and superiorly, and extended to the left relative to the apex of the morphologically left ventricle. The ventriculo-arterial connections were concordant in 1 patient, double outlet from the morphologically right ventricle in 2, and discordant in the other. In all 4 patients, it proved impossible to obtain the standard 4-chamber view showing simultaneously all four chambers and both atrioventricular valves. A series of apical 4-chamber or subcostal coronal views, obtained by tilting the transducer from posterior to anterior, demonstrate initially the connection of the left-sided left atrium and the right-sided left ventricle through the mitral valve. More anterior angulation of the transducer then showed the right-sided right atrium to be connected to the left-sided right ventricle through the tricuspid valve, confirming the presence of twisted atrioventricular connections. Color Doppler imaging displayed the crossing of the atrioventricular connections without mixing of the streams. Short-axis views across the ventricular mass confirmed that the right ventricle was superior, anterior, and to the left of the left ventricle, and demonstrated the horizontal position of the ventricular septum. When viewed subcostally, the distance between the tricuspid valve and the orifice of the inferior vena cava was significantly increased relative to normal findings. The echocardiographic findings were confirmed during surgical interventions in 3 patients, apart from the failure to diagnose one instance of persistent patency of the left superior vena cava. The failure to obtain a characteristic 4-chamber view in any cut was diagnostic for recognition of the criss-crossed atrioventricular junctions. Transthoracic echocardiography provides definitive images of this rare arrangement, and accurately defines the associated cardiac abnormalities. Copyright 2009. Published by Elsevier Ireland Ltd.

The Pathogenesis of Atrial and Atrioventricular Septal Defects with Special Emphasis on the Role of the Dorsal Mesenchymal Protrusion

PubMed Central

Briggs, Laura E.; Kakarla, Jayant; Wessels, Andy

2012-01-01

Partitioning of the four-chambered heart requires the proper formation, interaction and fusion of several mesenchymal tissues derived from different precursor populations that together form the atrioventricular mesenchymal complex. This includes the major endocardial cushions and the mesenchymal cap of the septum primum, which are of endocardial origin, and the dorsal mesenchymal protrusion (DMP), which is derived from the Second Heart Field. Failure of these structures to develop and/or fully mature results in atrial septal defects (ASDs) and atrioventricular septal defects (AVSD). AVSDs are congenital malformations in which the atria are permitted to communicate due to defective septation between the inferior margin of the septum primum and the atrial surface of the common atrioventricular valve. The clinical presentation of AVSDs is variable and depends on both the size and/or type of defect; less severe defects may be asymptomatic while the most severe defect, if untreated, results in infantile heart failure. For many years, maldevelopment of the endocardial cushions was thought to be the sole etiology of AVSDs. More recent work, however, has demonstrated that perturbation of DMP development also results in AVSD. Here, we discuss in detail the formation of the DMP, its contribution to cardiac septation and describe the morphological features as well as potential etiologies of ASDs and AVSDs. PMID:22709652

Repair of tetralogy of Fallot associated with atrioventricular septal defect.

PubMed

Tláskal, T; Hucín, B; Kostelka, M; Chaloupecký, V; Marek, J; Tax, P; Janouàek, J; Kuèera, V; Hruda, J; Reich, O; Skovránek, J

1998-01-01

Tetralogy of Fallot, when associated with atrioventricular septal defect permitting shunting at ventricular level, represents a complex cyanotic congenital malformation. Experience with surgical repair is limited, and results vary considerably. Between 1984 and 1996, we repaired 14 consecutive patients with this combination seen in our center. Their ages ranged from 8 months to 21 years (median 7.4 years). Six (42.9%) had Down's syndrome. In eight patients the correct diagnosis was made using echocardiography alone. In the remaining six patients, who had previously-constructed arterial shunts and/or suspected pulmonary arterial stenosis, catheterization and angiocardiography were also performed. The repair consisted of double patch closure of the septal defect, reconstruction of two atrioventricular orifices, and relief of pulmonary stenosis at all levels. In five patients with a hypoplastic pulmonary trunk, a monocusp transannular patch (four patients) or an allograft (one patient) was used for restoration of continuity from the right ventricle to the pulmonary arteries. Patch enlargement of one or both pulmonary arteries was necessary in five patients. One patient (7.1%) died early, and another late. The twelve surviving (85.8%) patients have been followed for 1.2-12.5 years after surgery (median 4.9 years, mean 5.9+/-3.9 years). During the follow-up, reoperation was necessary for repair of residual ventricular septal defect and pulmonary regurgitation in two patients, and closure of an atrial septal defect and alteration to left atrioventricular valvar regurgitation in one patient. Seven patients are in class I of the New York Heart Association, four in class II, and one in class III. Tetralogy of Fallot associated with atrioventricular septal defect can be corrected with low mortality and good long-term results. Residual lesions, however, have a tendency to progress, especially when seen in combination. After surgery, all patients need long-term close follow-up.

Variations in the structure of nexuses in the myocardium of the golden hamster Mesocricetus auratus.

PubMed Central

Skepper, J N; Navaratnam, V

1986-01-01

The structure of nexuses in the atrioventricular node of the golden hamster was studied with the transmission electron microscope, using thin sections and freeze-fracture replicas, and was compared with that of nexuses in the working myocardium of the right ventricular wall. Whereas ventricular myocardium contained macular nexuses only, nodal tissue contained annular and linear configurations as well as maculae of varying size. The significance of such variations in nexus pattern is not clear although several hypotheses are discussed in the literature. Measurements made on electron micrographs, after allowing for tilt of the specimen, yielded a particle diameter of 10.59 nm for nodal myocardium and 10.95 nm for ventricular myocardium, both measurements being substantially higher than figures generally cited in the literature. In each area the measurements had a normal distribution suggesting a single type of particle. The small but significant difference in particle size between the two areas is more likely to be caused by dissimilarities in packing arrangement rather than by differences in intrinsic structure or in functional state. Images Fig. 1 Fig. 3 PMID:3693102

Management of Arrhythmias in Heart Failure

PubMed Central

Masarone, Daniele; Limongelli, Giuseppe; Rubino, Marta; Valente, Fabio; Vastarella, Rossella; Ammendola, Ernesto; Gravino, Rita; Verrengia, Marina; Salerno, Gemma; Pacileo, Giuseppe

2017-01-01

Heart failure patients are predisposed to develop arrhythmias. Supraventricular arrhythmias can exacerbate the heart failure symptoms by decreasing the effective cardiac output and their control require pharmacological, electrical, or catheter-based intervention. In the setting of atrial flutter or atrial fibrillation, anticoagulation becomes paramount to prevent systemic or cerebral embolism. Patients with heart failure are also prone to develop ventricular arrhythmias that can present a challenge to the managing clinician. The management strategy depends on the type of arrhythmia, the underlying structural heart disease, the severity of heart failure, and the range from optimization of heart failure therapy to catheter ablation. Patients with heart failure, irrespective of ejection fraction are at high risk for developing sudden cardiac death, however risk stratification is a clinical challenge and requires a multiparametric evaluation for identification of patients who should undergo implantation of a cardioverter defibrillator. Finally, patients with heart failure can also develop symptomatic bradycardia, caused by sinus node dysfunction or atrio-ventricular block. The treatment of bradycardia in these patients with pacing is usually straightforward but needs some specific issue. PMID:29367535

Single-Ventricle Palliation in a 4-Year-Old With Ehlers-Danlos Syndrome.

PubMed

DeBoard, Zach M; Eckhauser, Aaron W; Griffiths, Eric

2018-01-01

We report the case of a 4-year-old boy with Ehlers-Danlos syndrome undergoing single-ventricle palliation for an unbalanced atrioventricular canal defect. No reports of single-ventricle palliation in the setting of connective tissue disorders exist in the current literature. Unique findings on the patient's preoperative imaging included a disproportionately large neoaortic root and a regurgitant atrioventricular valve, which may foretell the need for future intervention. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Relative position of the atrioventricular canal determines the electrical activation of developing reptile ventricles.

PubMed

Gregorovicova, Martina; Sedmera, David; Jensen, Bjarke

2018-04-19

Squamate reptiles appear to lack the specialized His/Purkinje system that enables the cardiac ventricle to be activated from apex to base as in mammals and birds. Instead, activation may simply spread from where the atrioventricular canal connects to the base. Gja5 , which encodes Cx40 that allows fast impulse propagation, was expressed throughout the ventricles of developing anole lizards. Activation was optically recorded in developing corn snake and central bearded dragon. Early embryonic ventricles were broad in shape, and activation propagated from the base to the right. Elongated ventricles of later stages were activated from base to apex. Before hatching, the snake ventricle developed a cranial extension on the left and activation now propagated from the base to the caudal apex and the cranial extension. In squamate reptiles, the pattern of electrical activation of the cardiac ventricle is dependent the position of the atrioventricular canal and the shape of the ventricle. © 2018. Published by The Company of Biologists Ltd.

Specialized impulse conduction pathway in the alligator heart

PubMed Central

Crossley, Dane A; Conner, Justin; Mohan, Rajiv A; van Duijvenboden, Karel; Postma, Alex V; Gloschat, Christopher R; Elsey, Ruth M; Sedmera, David; Efimov, Igor R

2018-01-01

Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy. PMID:29565246

Concomitant Wolff-Parkinson-White and Atrioventricular Nodal Reentrant Tachycardia: Which Pathway to Ablate?

PubMed

Sarsam, Sinan; Sidiqi, Ibrahim; Shah, Dipak; Zughaib, Marcel

2015-12-11

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of supraventricular tachycardia. In contrast, Wolff-Parkinson-White (WPW) pattern consists of an accessory pathway, which may result in the development of ventricular arrhythmias. Frequent tachycardia caused by AVNRT and accessory pathways may play a role in left ventricular systolic dysfunction. A 54-year-old man presented with palpitations and acute decompensated congestive heart failure. His baseline EKG showed Wolff-Parkinson-White (WPW) pattern. While hospitalized, he had an episode of atrioventricular nodal reentrant tachycardia (AVNRT). He underwent radiofrequency catheter ablation for AVNRT, and his accessory pathway was also ablated even though its conduction was found to be weak. He was clinically doing well on follow-up visit, with resolution of his heart failure symptoms and normalization of left ventricular function on echocardiography. This case raises the question whether the accessory pathway plays a role in the development of systolic dysfunction, and if there is any role for ablation in patients with asymptomatic WPW pattern.

[Fetal bradycardia: a retrospective study in 9 Spanish centers].

PubMed

Perin, F; Rodríguez Vázquez del Rey, M M; Deiros Bronte, L; Ferrer Menduiña, Q; Rueda Nuñez, F; Zabala Arguelles, J I; García de la Calzada, D; Teodoro Marin, S; Centeno Malfaz, F; Galindo Izquierdo, A

2014-11-01

The aim of this study is to review the current management and outcomes of fetal bradycardia in 9 Spanish centers. Retrospective multicenter study: analysis of all fetuses with bradycardia diagnosed between January 2008 and September 2010. Underlying mechanisms of fetal bradyarrhythmias were studied with echocardiography. A total of 37 cases were registered: 3 sinus bradycardia, 15 blocked atrial bigeminy, and 19 high grade atrioventricular blocks. Sinus bradycardia: 3 cases (100%) were associated with serious diseases. Blocked atrial bigeminy had an excellent outcome, except for one case with post-natal tachyarrhythmia. Of the atrioventricular blocks, 16% were related to congenital heart defects with isomerism, 63% related to the presence of maternal SSA/Ro antibodies, and 21% had unclear etiology. Overall mortality was 20% (37%, if terminations of pregnancy are taken into account). Risk factors for mortality were congenital heart disease, hydrops and/or ventricular dysfunction. Management strategies differed among centers. Steroids were administrated in 73% of immune-mediated atrioventricular blocks, including the only immune-mediated IInd grade block. More than half (58%) of atrioventricular blocks had a pacemaker implanted in a follow-up of 18 months. Sustained fetal bradycardia requires a comprehensive study in all cases, including those with sinus bradycardia. Blocked atrial bigeminy has a good prognosis, but tachyarrhythmias may develop. Heart block has significant mortality and morbidity rates, and its management is still highly controversial. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Does atrioventricular reentry tachycardia (AVRT) or atrioventricular nodal reentry tachycardia (AVNRT) in children affect their cognitive and emotional development?

PubMed

Maryniak, Agnieszka; Bielawska, Alicja; Bieganowska, Katarzyna; Miszczak-Knecht, Maria; Walczak, Franciszek; Szumowski, Lukasz

2013-04-01

The current study sought to assess cognitive and emotional functions among children and adolescents with atrioventricular reentry tachycardia (AVRT) and atrioventricular nodal reentry tachycardia (AVNRT). 113 patients (62 girls and 51 boys ages, 9-18 years) scheduled for radiofrequency ablation due to AVRT or AVNRT underwent neuropsychologic examination. The study excluded patients who had experienced cardiac arrest, congenital heart defects, neurologic disorders, or other diseases affecting cognitive or emotional development. Standardized tests for examining verbal and visual memory as well as visual-spatial functioning were performed. For patients exhibiting deficits in two or more tests, a diagnosis of "cognitive deficits" was determined. Levels of anxiety were tested using the State-Trait Anxiety Inventory. Cognitive deficits were found in 47.8 % of the patients. The age at first arrhythmia attack was related to memory dysfunction. The mean age at which the first symptoms occurred was significantly lower for patients with deficits (8.3 years) than for patients who had no deficit (10.2 years) (t = 2.15; p = 0.03). Boys exhibited a significantly higher level of trait anxiety than girls (t = 3.42; p = 0.0009). A significant negative correlation was found between anxiety and the age at appearance of the first symptoms (r = -0.26; p = 0.005). These findings led us to conclude that cognitive and emotional developments can be negatively affected by AVNRT and AVRT, particularly if tachycardia appears early in life.

[Embryology of the heart walls].

PubMed

Tardy, M-M; Galvaing, G; Sakka, L; Garcier, J-M; Chazal, J; Filaire, M

2013-03-01

Although anatomically simple structures, the atrial septum and the ventricular septum have complex embryological origins. Recent findings in molecular biology allowed better comprehension of their formation. As soon as the heart tube is formed, cells migrate from several cardiogenic fields to take part in the septation. Elongation, ballooning, and later inflexion of the heart tube create chamber separating grooves, facing the future septa. The systemic venous tributaries conflate at the venous pole of the heart; it will partially involute while contributing to the atrial septum. The primary atrial septum grows from the atrial roof towards the atrioventricular canal. It fuses there with the atrioventricular cushions, while its upper margin breaks down to form the ostium secundum. Then a deep fold develops from the atrial roof and partly covers the ostium secundum, leaving a flap-like interatrial communication through the oval foramen. It will close at birth. The interventricular septum has three embryological origins. The ventricular septum primum, created during the ballooning process, origins from the primary heart tube. It will form the trabecular septum and the inlet septum. The interventricular ring, surrounding the interventricular foramen, will participate in the inlet septum and also form the atrioventricular conduction axis. The outflow cushions will separate the outflow tract in the aorta and pulmonary artery, and grow to create the outlet septum. After merging with the atrioventricular cushions, they will also be part of the membranous septum. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Localization of cholinergic innervation and neurturin receptors in adult mouse heart and expression of the neurturin gene.

PubMed

Mabe, Abigail M; Hoard, Jennifer L; Duffourc, Michelle M; Hoover, Donald B

2006-10-01

Neurturin (NRTN) is a neurotrophic factor required during development for normal cholinergic innervation of the heart, but whether NRTN continues to function in the adult heart is unknown. We have therefore evaluated NRTN expression in adult mouse heart and the association of NRTN receptors with intracardiac cholinergic neurons and nerve fibers. Mapping the regional distribution and density of cholinergic nerves in mouse heart was an integral part of this goal. Analysis of RNA from adult C57BL/6 mouse hearts demonstrated NRTN expression in atrial and ventricular tissue. Virtually all neurons in the cardiac parasympathetic ganglia exhibited the cholinergic phenotype, and over 90% of these cells contained both components of the NRTN receptor, Ret tyrosine kinase and GDNF family receptor alpha2 (GFRalpha2). Cholinergic nerve fibers, identified by labeling for the high affinity choline transporter, were abundant in the sinus and atrioventricular nodes, ventricular conducting system, interatrial septum, and much of the right atrium, but less abundant in the left atrium. The right ventricular myocardium contained a low density of cholinergic nerves, which were sparse in other regions of the working ventricular myocardium. Some cholinergic nerves were also associated with coronary vessels. GFRalpha2 was present in most cholinergic nerve fibers and in Schwann cells and their processes throughout the heart. Some cholinergic nerve fibers, such as those in the sinus node, also exhibited Ret immunoreactivity. These findings provide the first detailed mapping of cholinergic nerves in mouse heart and suggest that the neurotrophic influence of NRTN on cardiac cholinergic innervation continues in mature animals.

Parametric Analysis of Airland Combat Model in High Resolution

DTIC Science & Technology

1988-09-01

continue Fprint MOE, UTILITY matrix figure 10. Flow chart of the advanced model 22 WAVE2 = numeric value (1. 2. or 12) which is supposed to be given by the...model user" if WAVE2 = 1. it will bc a BATTLE I case. and all Red forccs on Av’enue-2 attack to nodc-2S ; if \\VAVE2= 2. it will also be a BATTLE I case...but all Red forces on Aenue-2 attack to node-27 ; if WAVE2 = 12. it will be a BATTLE2 case. These outputs will be analyzed in more detail in the next

An extremely rare clinical entity: congenitally corrected transposition with situs ınversus and single coronary artery presented with complete atrioventricular block in a young man.

PubMed

Cirakoglu, Omer Faruk; Bayraktar, Ali; Sayin, Muhammet Rasit

2018-05-01

Congenitally corrected transposition of the great arteries is a rare form of CHD. Situs inversus is a much less common variant of a congenitally corrected transposition of the great arteries. In rare cases, transposition events may be accompanied by various cardiac anomalies. However, situs inversus patients with congenitally corrected transposition, single coronary artery anomaly, and atrioventricular block together have not been reported previously. This combination of abnormalities is presented as a first in the literature.

Total prosthetic replacement of atrioventricular valves in the dog

PubMed Central

Den Otter, G.

1968-01-01

The free-floating cone and cage valve, described in a previous study as being successful as a substitute for the right atrioventricular valve, does not perform well when it is inserted in the mitral ostium. A tilting cone or disc was constructed and tested in a series of 15 dogs. This prosthesis gave excellent results in 12 animals. The reasons for its failure in the remaining three is discussed. The prosthesis presented has advantages over any ball and cage valve, mainly because of its smaller volume. Images PMID:5654076

Outcome of Radiofrequency Catheter Ablation as a non-pharmacological therapy for idiopathic Ventricular Tachycardia.

PubMed

Samore, Naseer Ahmed; Imran Majeed, Syed Muhammad; Kayani, Azhar Mahmud; Bhalli, Muhammad Asif; Shabbir, Muhammad

2009-09-01

To determine the outcome of Radiofrequency Catheter Ablation (RFCA) as a non-pharmacological curative therapy for idiopathic Ventricular Tachycardia (VT) and to identify procedure-related complications. Descriptive study. The Armed Forces Institute of Cardiology and National Institute of Heart Diseases, Rawalpindi, from February 2001 to October 2008. Ninety eight consecutive patients with idiopathic VT, resistant to drug therapy, who underwent Electrophysiology Studies (EPS) radiofrequency catheter ablation were enrolled. Clinical and electrophysiological variables were recorded and a descriptive analysis was done. Out of the 98 patients, 79 were males (80.6%). The mean age was 33.29+11.93 years. Modes of presentation were sustained VT, Repetitive Monomorphic VT (RMVT), Non-sustained VT (NSVT) and Ventricular Premature Beats (VPBs). Right Ventricular Outflow Tract (RVOT) VT was found in 37 patients, 37 had Idiopathic Left Ventricular Tachycardia (ILVT), 20 had Left Ventricular Outflow Tract (LVOT) VT, and Inflow Right Ventricular Tachycardia (IRVT) was found in 7 patients. Other sites of origin of VT were infrequent. Eight patients had dual morphologies of VT. Atrioventricular Nodal Re-entry Tachycardia (AVNRT) was found in 8 patients. RFCA was successful in abolishing inducible VT in 88 patients. One patient developed complete AV block requiring a permanent pacemaker. Results of this study confirm a high degree of success and safety of radiofrequency catheter ablation as curative therapy for idiopathic ventricular tachycardia.

Two cases of bradyarrhythmia and hypotension after extradural injections in dogs.

PubMed

Iff, Isabelle; Moens, Yves

2008-05-01

Two healthy obese, seven-year-old, female Rottweilers weighing 40 and 57 kg were submitted for cranial cruciate repair. They were premedicated with intravenous methadone (0.1 mg kg(-1)) and acepromazine (0.01 and 0.02 mg kg(-1)). Anesthesia was induced with propofol (3.6 and 2.5 mg kg(-1)) and maintained with isoflurane in oxygen using a circle breathing system. The dogs were placed in sternal recumbency and epidural injection of lidocaine/bupivacaine or lidocaine/bupivacaine/morphine (0.2 mL/kg, 8 and 11 mL) was carried out over 1.5 and 4 minutes. Epidural pressures were 79 and 72 mmHg at the end of the injections. The first dog's heart rate decreased from 80 to 65 beats minute(-1) with a second degree atrioventricular (AV) block. The arterial pressure decreased from 100 to 50 mmHg. These responded to atropine (0.01 mg kg(-1) IV). The second dog's heart rate decreased from 120 to 60 beats minute(-1) while arterial pressure decreased from 72 to 38 mmHg. No treatment was given and heart rate and arterial blood pressure returned to acceptable ranges. These cases suggest that large increases in epidural pressure may cause significant cardiovascular effects. This may be avoided by using lower volumes and discontinuing injection if significant back pressure is detected.

Is right ventricular mid-septal pacing superior to apical pacing in patients with high degree atrio-ventricular block and moderately depressed left ventricular function?

PubMed

Chen, Kang; Mao, Ye; Liu, Shao-hua; Wu, Qiong; Luo, Qing-zhi; Pan, Wen-qi; Jin, Qi; Zhang, Ning; Ling, Tian-you; Chen, Ying; Gu, Gang; Shen, Wei-feng; Wu, Li-qun

2014-06-01

We are aimed to investigate whether right ventricular mid-septal pacing (RVMSP) is superior to conventional right ventricular apical pacing (RVAP) in improving clinical functional capacity and left ventricular ejection fraction (LVEF) for patients with high-degree atrio-ventricular block and moderately depressed left ventricle (LV) function. Ninety-two patients with high-degree atrio-ventricular block and moderately reduced LVEF (ranging from 35% to 50%) were randomly allocated to RVMSP (n=45) and RVAP (n=47). New York Heart Association (NYHA) functional class, echocardiographic LVEF, and distance during a 6-min walk test (6MWT) were determined at 18 months after pacemaker implantation. Serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Compared with baseline, NYHA functional class remained unchanged at 18 months, distance during 6MWT (485 m vs. 517 m) and LVEF (36.7% vs. 41.8%) were increased, but BNP levels were reduced (2352 pg/ml vs. 710 pg/ml) in the RVMSP group compared with those in the RVAP group, especially in patients with LVEF 35%-40% (for all comparisons, P<0.05). However, clinical function capacity and LV function measurements were not significantly changed in patients with RVAP, despite the pacing measurements being similar in both groups, such as R-wave amplitude and capture threshold. RVMSP provides a better clinical utility, compared with RVAP, in patients with high-degree atrioventricular block and moderately depressed LV function whose LVEF levels ranged from 35% to 40%.

New-onset third-degree atrioventricular block because of autoimmune-induced myositis under treatment with anti-programmed cell death-1 (nivolumab) for metastatic melanoma.

PubMed

Behling, Juliane; Kaes, Joachim; Münzel, Thomas; Grabbe, Stephan; Loquai, Carmen

2017-04-01

There has been considerable progress in treating malignant melanoma over the last few years. The immune-checkpoint-inhibitors nivolumab and pembrolizumab have been approved by the Food and Drug Administration in 2014 for the therapy of metastatic melanoma. Anti-programmed cell death-1-blocking antibodies are known to cause immune-related adverse events. Physicians should be aware of common and rare side effects and pay attention to new ones. We therefore report a severe and life-threatening side effect of anti-programmed cell death-1 immunotherapy with nivolumab that has not been previously reported: the development of a third-degree atrioventricular block. After a second infusion with nivolumab, our patient developed a troponin I-positive and autoantibody-positive myositis and a few days later a new-onset third-degree atrioventricular block. This is most likely because of an autoimmune-induced myositis with a cardiac impairment in terms of a myocarditis, which led to an impairment of the conduction of cardiac electrical stimuli.

[Recording and data processing of electrical signals of the specific atrioventricular conduction pathways in man].

PubMed

Héron, F; Mialet, G; Schuller, C; Breton, D; Perrin, J; Degeorges, M

1979-01-01

Signals of the electrical activity of the specific atrioventricular conduction pathways were recorded with an unipolar lead to obtain an exact time reference. The amplifier used had special characteristics: high gain settings (up to 300,000), very low noise levels, and wide filter range (2 Hz - 1,600 Hz). The low amplitude of the signals under study, of the order of a microvolt, and the wide filter range of the amplifier necessitated placing the patient in a Faraday cage. The signals recorded on magnetic tape were treated by a system of analysis for signal treatment. The method of averaging was used to extract the signal from background noise especially that arising from somatic muscle. The amplitude of the Hisian signal was much larger than that usually obtained with other methods. The intervals were determined with precision of the order of 1 millisecond. Frequential analysis of the signals gave another representation of the information contained in the time signals. This new representation seems to give better discrimination of the different zones of activation of the specific atrioventricular conduction pathways.

Spatially divergent cardiac responses to nicotinic stimulation of ganglionated plexus neurons in the canine heart.

PubMed

Cardinal, René; Pagé, Pierre; Vermeulen, Michel; Ardell, Jeffrey L; Armour, J Andrew

2009-01-28

Ganglionated plexuses (GPs) are major constituents of the intrinsic cardiac nervous system, the final common integrator of regional cardiac control. We hypothesized that nicotinic stimulation of individual GPs exerts divergent regional influences, affecting atrial as well as ventricular functions. In 22 anesthetized canines, unipolar electrograms were recorded from 127 atrial and 127 ventricular epicardial loci during nicotine injection (100 mcg in 0.1 ml) into either the 1) right atrial (RA), 2) dorsal atrial, 3) left atrial, 4) inferior vena cava-inferior left atrial, 5) right ventricular, 6) ventral septal ventricular or 7) cranial medial ventricular (CMV) GP. In addition to sinus and AV nodal function, neural effects on atrial and ventricular repolarization were identified as changes in the area subtended by unipolar recordings under basal conditions and at maximum neurally-induced effects. Animals were studied with intact AV node or following ablation to achieve ventricular rate control. Atrial rate was affected in response to stimulation of all 7 GPs with an incidence of 50-95% of the animals among the different GPs. AV conduction was affected following stimulation of 6/7 GP with an incidence of 22-75% among GPs. Atrial and ventricular repolarization properties were affected by atrial as well as ventricular GP stimulation. Distinct regional patterns of repolarization changes were identified in response to stimulation of individual GPs. RAGP predominantly affected the RA and posterior right ventricular walls whereas CMVGP elicited biatrial and biventricular repolarization changes. Spatially divergent and overlapping cardiac regions are affected in response to nicotinic stimulation of neurons in individual GPs.

Flail Tricuspid Valve in an Adult Patient with Congenitally Corrected Transposition of the Great Arteries.

PubMed

Meloni, Luigi; Abbruzzese, Piero A.; Pirisi, Raimondo; Cherchi, Angelo

1997-01-01

We describe a case of a 50-year-old woman with congenitally corrected transposition of the great vessels, in whom severe left-sided tricuspid (systemic atrioventricular) valve insufficiency was the only associated anomaly. The tricuspid valve was dysplastic and abnormally oriented toward the interventricular septum, without the downward displacement of Ebstein's anomaly. The mechanism of atrioventricular regurgitation was unusual in that it consisted of the rupture of chordae tendineae of both the anterior and septal leaflets. The left-sided tricuspid valve was replaced with a St. Jude prosthesis and the postoperative course was uneventful.

Complete atrioventricular block as initial manifestation of systemic lupus erythematosus.

PubMed

Arce-Salinas, C A; Carmona-Escamilla, M A; Rodríguez-García, F

2009-01-01

Only a few cases of complete atrioventricular block (AVB) in adult lupus patients have been previously described, but only one as the initial manifestation. A 19-year-old woman who presented with seizures and loss of consciousness, was diagnosed with complete ABV and underwent pacemaker placement. Over the next weeks she developed serositis, joint, cutaneous, and renal involvement; positive antinuclear antibodies and high anti-SSA/Ro titers. This is the second case with AVB as a feature of SLE at onset. A review of previous complete AVB cases of adult SLE patients is presented.

Mechanism of polyuria and natriuresis in atrioventricular nodal tachycardia.

PubMed Central

Canepa-Anson, R; Williams, M; Marshall, J; Mitsuoka, T; Lightman, S; Sutton, R

1984-01-01

A woman with tachycardia associated with polyuria was investigated. Electrophysiological analysis showed that the tachycardia was an atrioventricular nodal re-entrant tachycardia. Programmed stimulation was then used to provoke and sustain the tachycardia for 40 minutes. Polyuria, with an appreciable increase in free water clearance, was observed. This was associated with reduction in plasma and urinary arginine vasopressin concentrations. Appreciable natriuresis also developed. These results support the hypothesis that the polyuria with increased free water clearance and the natriuresis occurring during sustained tachycardia in man are due to inhibition of secretion of vasopressin and the release of natriuretic factor. PMID:6434116

Identification of nodal tissue in the living heart using rapid scanning fiber-optics confocal microscopy and extracellular fluorophores.

PubMed

Huang, Chao; Kaza, Aditya K; Hitchcock, Robert W; Sachse, Frank B

2013-09-01

Risks associated with pediatric reconstructive heart surgery include injury of the sinoatrial node (SAN) and atrioventricular node (AVN), requiring cardiac rhythm management using implantable pacemakers. These injuries are the result of difficulties in identifying nodal tissues intraoperatively. Here we describe an approach based on confocal microscopy and extracellular fluorophores to quantify tissue microstructure and identify nodal tissue. Using conventional 3-dimensional confocal microscopy we investigated the microstructural arrangement of SAN, AVN, and atrial working myocardium (AWM) in fixed rat heart. AWM exhibited a regular striated arrangement of the extracellular space. In contrast, SAN and AVN had an irregular, reticulated arrangement. AWM, SAN, and AVN tissues were beneath a thin surface layer of tissue that did not obstruct confocal microscopic imaging. Subsequently, we imaged tissues in living rat hearts with real-time fiber-optics confocal microscopy. Fiber-optics confocal microscopy images resembled images acquired with conventional confocal microscopy. We investigated spatial regularity of tissue microstructure from Fourier analysis and second-order image moments. Fourier analysis of fiber-optics confocal microscopy images showed that the spatial regularity of AWM was greater than that of nodal tissues (37.5 ± 5.0% versus 24.3 ± 3.9% for SAN and 23.8 ± 3.7% for AVN; P<0.05). Similar differences of spatial regularities were revealed from second-order image moments (50.0 ± 7.3% for AWM versus 29.3 ± 6.7% for SAN and 27.3 ± 5.5% for AVN; P<0.05). The study demonstrates feasibility of identifying nodal tissue in living heart using extracellular fluorophores and fiber-optics confocal microscopy. Application of the approach in pediatric reconstructive heart surgery may reduce risks of injuring nodal tissues.

Atrioventricular depolarization differences identify coronary artery anomalies in Kawasaki disease.

PubMed

Cortez, Daniel; Sharma, Nandita; Jone, Pei-Ni

2017-03-01

Kawasaki disease (KD) is the leading cause of acquired heart disease in children. Signal average electrocardiogram changes in patients during the acute phase of KD with coronary artery anomalies (CAA) include depolarization changes. We set out to determine if 12-lead-derived atrioventricular depolarization differences can identify CAA in patients with KD. A blinded, retrospective case-control study of patients with KD was performed. Deep Q waves, corrected QT-intervals (QTc), spatial QRS-T angles, T-wave vector magnitudes (RMS-T), and a novel parameter for assessment of atrioventricular depolarization difference (the spatial PR angle) and a two dimensional PR angle were assessed. Comparisons between groups were performed to test for significant differences. One hundred one patients with KD were evaluated, with 68 having CAA (67.3%, mean age 3.6 ± 3.0 years, 82.6% male), and 32 without CAA (31.7%, mean age 2.7 ± 3.2 years, 70.4% male). The spatial PR angle significantly discriminated KD patients with CAA from those without, 59.7° ± 31.1° versus 41.6° ± 11.5° (p < .001). A spatial PR angle cutoff value of 56.9° gave positive/negative predictive values and odds ratios of 93.8%, 43.5%, and 11.5% (95% confidence interval (CI) 2.6-52.2). The two dimensional PR angle either below 7° or above 92° gave positive/negative predictive values and odds ratios of 100.0%, 38.8%, and 21.1% (95% CI 1.2-362.8). No other parameters significantly differentiated the groups. Atrioventricular depolarization differences, measured by the spatial or two dimensional PR angle differentiate KD patients with CAA versus those without. © 2016 Wiley Periodicals, Inc.

Impact of pacemaker mode in patients with atrioventricular conduction disturbance after trans-catheter aortic valve implantation.

PubMed

Takahashi, Masao; Badenco, Nicolas; Monteau, Jacques; Gandjbakhch, Estelle; Extramiana, Fabrice; Urena, Marina; Karam, Nicole; Marijon, Eloi; Algalarrondo, Vincent; Teiger, Emmanuel; Lellouche, Nicolas

2018-03-14

This study aimed to assess the impact of pacemaker mode programming on clinical outcomes in patients with high-degree atrioventricular conduction disturbance (AVCD) after transcatheter aortic valve implantation (TAVI). Although high-degree AVCD after TAVI can receive pacemaker, recovery of the AVCD is often observed. Specific pacemaker algorithms (AAI-DDD mode switch) are available which favor spontaneous atrioventricular conduction. Of 1,621 consecutive multi-center TAVI patients, 269 (16.4%) received pacemaker. We retrospectively included 91 patients with persistent high-degree AVCD at hospital discharge. Pacemaker dependency was defined as absence, inadequate intrinsic ventricular rhythm, or ventricular pacing time > 95% on pacemaker interrogation during follow-up. Comparison of heart failure hospitalization and death between conventional DDD (cDDD) and other modes was examined (AAI-DDD and VVI). During a mean follow-up duration of 13 months, the pacemaker dependency rate was 52.8%. Patients with cDDD mode (N = 36: 40.0%) had significantly more pacemaker dependency. Multivariate analysis showed that cDDD mode was independently associated with pacemaker dependency (odds ratio = 3.63, P = 0.03). Moreover, cDDD patients had a significant higher incidence of heart failure hospitalization (Hospitalization: cDDD vs. others = 45.4% vs. 18.2%, P = 0.03) and had a higher incidence of mortality (Death: cDDD vs. the others = 27.0% vs. 4.4%, P = 0.06). Up to half of patients implanted for high-degree AVCD after TAVI had conduction recovery. Patients with cDDD programming at hospital discharge had more pacemaker dependency and a worse cardiac prognosis. Thus, pacemaker mode should be systematically set to promote spontaneous atrioventricular conduction in patients with pacemaker implantation after TAVI. © 2018 Wiley Periodicals, Inc.

Morphometric features of the right atrioventricular orifice in adult human hearts.

PubMed

Skwarek, M; Hreczecha, J; Dudziak, M; Jerzemowski, J; Szpinda, M; Grzybiak, M

2008-02-01

The normal data of the tricuspid valve complex is of great clinical importance in the light of progress in cardiosurgery and the development of novel operating techniques. A range of measurements for the right atrioventricular orifice in 96 human adult hearts was examined by means of anatomical dissection, inspection, examination, and statistical analyses. The length of the attachment of the anterior leaflet increased significantly between group I (aged 18-40 years) and group II (aged 41-64 years) in women only. In men there were no significant differences in this parameter between any of the three age groups. In addition, the attachment length of the posterior leaflet in women increased statistically in the second age group. In men, in contrast, the attachment length of the posterior leaflet did not increase significantly between the first and second age groups and became significantly larger only in oldest age group, consisting of men aged over 65. No statistically significant differences between the three age groups were found for the attachment length of the septal leaflet (p>0.05). In female hearts significant increases in the frontal and sagittal dimensions of the tricuspid valve orifice were observed between the second age group and the group aged over 65. In male hearts both the frontal and sagittal dimensions increased significantly with advanced age. The right atrioventricular orifice expressed as the ellipse area was statistically greater than the triangular area (p<0.01) in each age group. It should be noticed that both areas increased significantly during ageing. This study has demonstrated that the shape of the right atrioventricular orifice evolves during life, from a triangular shape to a more elliptical shape.

Variants of Transient Receptor Potential Melastatin Member 4 in Childhood Atrioventricular Block.

PubMed

Syam, Ninda; Chatel, Stéphanie; Ozhathil, Lijo Cherian; Sottas, Valentin; Rougier, Jean-Sébastien; Baruteau, Alban; Baron, Estelle; Amarouch, Mohamed-Yassine; Daumy, Xavier; Probst, Vincent; Schott, Jean-Jacques; Abriel, Hugues

2016-05-20

Transient receptor potential melastatin member 4 (TRPM4) is a nonselective cation channel. TRPM4 mutations have been linked to cardiac conduction disease and Brugada syndrome. The mechanisms underlying TRPM4-dependent conduction slowing are not fully understood. The aim of this study was to characterize TRPM4 genetic variants found in patients with congenital or childhood atrioventricular block. Ninety-one patients with congenital or childhood atrioventricular block were screened for candidate genes. Five rare TRPM4 genetic variants were identified and investigated. The variants were expressed heterologously in HEK293 cells. Two of the variants, A432T and A432T/G582S, showed decreased expression of the protein at the cell membrane; inversely, the G582S variant showed increased expression. Further functional characterization of these variants using whole-cell patch-clamp configuration showed a loss of function and a gain of function, respectively. We hypothesized that the observed decrease in expression was caused by a folding and trafficking defect. This was supported by the observation that incubation of these variants at lower temperature partially rescued their expression and function. Previous studies have suggested that altered SUMOylation of TRPM4 may cause a gain of function; however, we did not find any evidence that supports SUMOylation as being directly involved for the gain-of-function variant. This study underpins the role of TRPM4 in the cardiac conduction system. The loss-of-function variants A432T/G582S found in 2 unrelated patients with atrioventricular block are most likely caused by misfolding-dependent altered trafficking. The ability to rescue this variant with lower temperature may provide a novel use of pharmacological chaperones in treatment strategies. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Risk of malignant arrhythmias in initially symptomatic patients with Wolff-Parkinson-White syndrome: results of a prospective long-term electrophysiological follow-up study.

PubMed

Pappone, Carlo; Vicedomini, Gabriele; Manguso, Francesco; Baldi, Mario; Pappone, Alessia; Petretta, Andrea; Vitale, Raffaele; Saviano, Massimo; Ciaccio, Cristiano; Giannelli, Luigi; Calovic, Zarko; Tavazzi, Luigi; Santinelli, Vincenzo

2012-02-07

The available amount of detailed long-term data in patients with Wolff-Parkinson-White syndrome is limited, and no prospective electrophysiological studies looking at predictors of malignant arrhythmia are available. Among 8575 symptomatic Wolff-Parkinson-White patients with atrioventricular reentrant tachycardia referred for electrophysiological test, 369 (mean age, 23±12.5 years) declined catheter ablation and were followed up. The primary end point of the study was to evaluate over a 5-year follow-up the predictors and characteristics of patients who develop malignant arrhythmias. After a mean follow-up of 42.1±10 months, malignant arrhythmias developed in 29 patients (mean age, 13.9±5.6 years; 26 male), resulting in presyncope/syncope (25 patients), hemodynamic collapse (3 patients), or cardiac arrest caused by ventricular fibrillation (1 patient). Of the remaining 340 patients, 168 (mean age, 34.2±9.0 years) remained asymptomatic up to 5 years, and 172 (mean age, 13.6±5.1 years) had benign recurrence, including sustained atrioventricular reentrant tachycardia (132 patients) or atrial fibrillation (40 patients). Compared with the group with no malignant arrhythmias, the group with malignant arrhythmias showed shorter accessory-pathway effective refractory period (P<0.001) and more often exhibited multiple accessory pathways (P<0.001), and atrioventricular reentrant tachycardia triggering sustained pre-excited atrial fibrillation was more frequently inducible (P<0.001). Multivariable analysis demonstrated that short accessory-pathway effective refractory period (P<0.001) and atrioventricular reentrant tachycardia triggering sustained pre-excited atrial fibrillation (P<0.001) were independent predictors of malignant arrhythmias. Symptomatic patients with Wolff-Parkinson-White syndrome generally have a good outcome, and predictors of malignant arrhythmias are similar to those reported for asymptomatic patients with ventricular pre-excitation.

Interrelationships between the heart and central nervous system: localization of neuro-transmitters and imaging of their associated nuclei, including the raphe nuclei & the locus coeruleus, as well as the imaging of the heart and its representation areas in slices of the human central nervous system using the "Bi-Digital O-Ring Test" imaging method.

PubMed

Omura, Y

1987-01-01

Using microscopic slides of specific tissues from the human body or pure substances including neuro-transmitters such as serotonin, dopamine, norepinephrine, etc., as reference control substances in the Bi-Digital O-Ring Test Molecular Identification Method, the author was able to localize and image normal and abnormal internal organs, and to localize and trace the distribution of neurotransmitters in the different parts of the central nervous system. Using microscopic slides of different parts of the heart, we were able to image the outline of the heart as well as the SA node, AV node, tricuspid valve, mitral valve, aortic valve, pulmonary valve, coronary arteries, and aorta and its branches, including the vertebral arteries, without using any bulky or expensive imaging instruments. Using serotonin as a reference control substance on the different parts of the central nervous system, it was possible to demonstrate the 6 well-known raphe nuclei and the locus coeruleus (which contains serotonin & norepinephrine), as well as the distribution of serotonin in the cerebrum and the cerebellum, all of which closely resembled previously published well-known neuroanatomical structures and distributions of neurotransmitters. As an extension of this work, possible representations of different internal organs on the central nervous system were examined using microscopic slides of different internal organs as reference control substances. The results indicated that the entire heart is represented primarily in the medulla oblongata, and that the SA node and the upper half of the left atrium are represented in the caudal end of the pons; the right side of the heart (i.e. R-atrium, AV node, tricuspid valve, R-ventricle) is represented on the right side of the medulla oblongata, and the left side of the heart (i.e. lower half of the L-atrium, mitral valve, L-ventricle) is represented on the left side of the medulla oblongata, and the upper half of the left atrium is represented in the caudal end of the left side of the pons. The bottoms of the ventricles are located near the spinal cord. Furthermore, the right and the left sides of the heart are represented in specific areas of each side of the right and left hemispheres of the cerebral cortex, and there are connecting pathways between the representation areas of identical parts of the heart, through the corpus callosum and other neuro-pathways.

Post-operative ventricular flow dynamics following atrioventricular valve surgical and device therapies: A review.

PubMed

Nguyen, Yen Ngoc; Ismail, Munirah; Kabinejadian, Foad; Tay, Edgar Lik Wui; Leo, Hwa Liang

2018-04-01

Intra-ventricular flow dynamics has recently emerged as an important evaluation and diagnosis tool in different cardiovascular conditions. The formation of vortex pattern during the cardiac cycle has been suggested to play important epigenetic and energy-modulation roles in cardiac remodelling, adaptations and mal-adaptations. In this new perspective, flow alterations due to different cardiovascular procedures can affect the long-term outcome of those procedures. Especially, repairs and replacements performed on atrioventricular valves are likely to exert direct impact on intra-ventricular flow pattern. In this review, current consensus around the roles of vortex dynamics in cardiac function is discussed. An overview of physiological vortex patterns found in healthy left and right ventricles as well as post-operative ventricular flow phenomenon owing to different atrioventricular valvular procedures are reviewed, followed by the summary of different vortex identification schemes used to characterise intraventricular flow. This paper also emphasises on future research directions towards a comprehensive understanding of intra-cardiac flow and its clinical relevance. The knowledge could encourage more effective pre-operative planning and better outcomes for current clinical practices. Copyright © 2018. Published by Elsevier Ltd.

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

PubMed

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

2018-05-01

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

[The effect of atrial pacing on left ventricular diastolic function and BNP levels in patients with DDD pacemaker].

PubMed

Apali, Zeynep; Bayata, Serdar; Yeşil, Murat; Arikan, Erdinç; Postaci, Nursen

2010-08-01

We aimed to investigate the effect of atrial pacing on left ventricular diastolic function and brain natriuretic peptide (BNP) levels in patients with DDD pacemaker. Thirty patients with complete atrio-ventricular (AV) block and DDD pacemaker were included. All patients had normal left ventricular systolic function. Echocardiographic diastolic function parameters (transmitral and tissue Doppler velocities during early (E and E') and late (A and A') filling) and NT-pro-BNP levels were evaluated prospectively during atrial sensing and pacing periods. Echocardiographic data were compared with paired sample t test and NT-pro-BNP levels were compared with Wilcoxon test. Echocardiographic E/A, E'/A', E/E' ratios were calculated as 0.72+/-0.34, 0.61+/-0.21 and 8.76+/-2.58 during atrial sensing period. Same parameters were found as 0.71+/-0.23, 0.64+/-0.16 and 8.93+/-3.16 respectively during atrial pacing period. Echocardiographic left ventricular diastolic function parameters were not significantly different during atrial pacing and atrial sensing periods. Median plasma NT-pro-BNP levels were measured as 142 pg/ml (min-max 47-563 pg/ml) and 147 pg/ml (min-max 33-1035 pg/ml) during atrial sensing and pacing periods respectively. These levels were not significantly different (p=0.86). The result of this study has shown that, atrial pacing has not any additional detrimental effect on left ventricular diastolic function parameters in paced patients with normal left ventricular systolic function.

Masquerading bundle branch block as a presenting manifestation of complete atrioventricular block that caused syncope.

PubMed

Jiao, Zhenyu; Tian, Ying; Yang, Xinchun; Liu, Xingpeng

2017-10-01

A 59-year-old male patient was admitted with the main complaints of stuffiness and shortness of breath. An ECG from precordial leads on admission showed masquerading bundle branch block. Syncope frequently occurred after admission. During syncope episodes, ECG telemetry showed that the syncope was caused by intermittent complete atrioventricular block, with the longest RR interval lasting for 4.36 s. At the gap of syncope, ECG showed complete right bundle branch block accompanied by alternation of left anterior fascicular block and left posterior fascicular block. The patient was implanted with a dual-chamber permanent pacemaker. Follow-up of 9 months showed no reoccurrence of syncope.

Lyme carditis. Electrophysiologic and histopathologic study

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

Reznick, J.W.; Braunstein, D.B.; Walsh, R.L.

1986-11-01

To further define the nature of Lyme carditis, electrophysiologic study and endomyocardial biopsy were performed in a patient with Lyme disease, whose principal cardiac manifestation was high-degree atrioventricular block. Intracardiac recording demonstrated supra-Hisian block and complete absence of an escape mechanism. Gallium 67 scanning demonstrated myocardial uptake, and right ventricular endomyocardial biopsy revealed active lymphocytic myocarditis. A structure compatible with a spirochetal organism was demonstrated in one biopsy specimen. It is concluded that Lyme disease can produce active myocarditis, as suggested by gallium 67 imaging and confirmed by endomyocardial biopsy. Furthermore, the presence of high-grade atrioventricular block in this diseasemore » requires aggressive management with temporary pacemaker and corticosteroid therapy.« less

Totally robotic repair of atrioventricular septal defect in the adult.

PubMed

Gao, Changqing; Yang, Ming; Xiao, Cangsong; Zhang, Huajun

2015-11-06

Atrioventricular septal defect (AVSD) accounts for up to 3 % of congenital cardiac defects, which is routinely repaired via median sternotomy. Minimally invasive approach such as endoscopic or robotic assisted repair for AVSD has not been reported in the literature. With the experience with robotic mitral valve surgery and congenital defect repair, we initiated robotic AVSD repair in adults. In this report, we presented three cases of successful repair of partial and intermediate AVSD by using da Vinci SI surgical system (Intuitive Surgical, Inc., Sunnyvale, CA). Totally robotic AVSD repair via right atriotomy could be safely performed in adults and it may provide superior cosmesis with the comparable surgical outcome of the repair via sternotomy.

SHERLOCK 3CG™ Diamond Tip Confirmation System

ClinicalTrials.gov

2018-05-15

Indication for Peripheral Intravenous Catheterization; Atrial Flutter; Premature Atrial Contraction; Premature Ventricular Contraction; Premature Junctional Contraction; Tachycardia; Atrioventricular Block; Bundle-Branch Block

Prospective Observational Cohort Study of Fetal Atrial Flutter & Supraventricular Tachycardia

ClinicalTrials.gov

2017-12-15

Atrial Flutter; Tachycardia, Supraventricular; Tachycardia, Atrial Ectopic; Tachycardia, Reciprocating; Tachycardia Atrial; Tachycardia, Atrioventricular Nodal Reentry; Tachycardia, Paroxysmal; Fetal Hydrops

Endocardial cushion defect

MedlinePlus

... Philadelphia, PA: Elsevier; 2016:chap 426. Kouchoukos NT, Blackstone EH, Hanley FL, Kirklin JK. Atrioventricular septal defect. In: Kouchoukos NT, Blackstone EH, Hanley FL, Kirklin JK, eds. Kirklin/Barratt- ...

Junctional tachycardia in a child with non-rheumatic fever streptococcal pharyngitis.

PubMed

Bansal, Neha; Karpawich, Peter P; Sriram, Chenni S

2017-07-01

Accelerated junctional rhythm has been reported in children in the setting of acute rheumatic fever; however, we describe a hitherto unreported case of isolated junctional tachycardia in a child with streptococcal pharyngitis, not meeting revised Jones criteria for rheumatic fever. A previously healthy, 9-year-old girl presented to the emergency department with complaints of sore throat, low-grade fever, and intermittent chest pain. She was found to have a positive rapid streptococcal antigen test. The initial electrocardiogram showed junctional tachycardia with atrioventricular dissociation in addition to prolonged and aberrant atrioventricular conduction. An echocardiogram revealed normal cardiac anatomy with normal biventricular function. The patient responded to treatment with amoxicillin for streptococcal pharyngitis. The junctional tachycardia and other electrocardiogram abnormalities resolved during follow-up.

Simulation system of arrhythmia using ActiveX control.

PubMed

Takeuchi, Akihiro; Hirose, Minoru; Hamada, Atsushi; Ikeda, Noriaki

2005-07-01

A simulation system for arrhythmias has been developed using Windows-based software technology, ActiveX control. The cardiac module consists of six cells, the sinus, atrium, AV node, ventricle, and ectopic foci. The physiological properties of the cells, the automaticity and conduction delay, were modelled, respectively, by the phase response curve and the excitability recovery curve. Cell functions were implemented in the ActiveX control and incorporated into the cardiac module. The system draws the ECG sequence as a ladder diagram in real time. The system interactively shows diverse arrhythmias for various user settings of the cell function and bidirectional conduction between the cells. Users are able to experiment virtually by setting up a so-called electrophysiological stimulation. This system is useful for learning and for teaching the interaction between the cells and arrhythmias.

Discrete-Event-Dynamic-System-Based Approaches for Control in Integrated Voice/Data Multihop Radio Networks.

DTIC Science & Technology

1994-12-07

set Ci is such that i C_ A and, in general, Ci n Cj 0 for i # j, The importance of the distinction n o ýt a av1 itIam i; the t Ulm hIt I 9B i l 16 a...be the M-dimensional slot assignment probability vector [01, . ., ’iM] T and Wi(0) as the expected node i waiting time. Our objective is to determine...Nominal Sample Path BP#m BP # (m+l) I I I! I I II * I II ,m A2,m :A3,m VIl m T l m T2,m 13 V3,m Figure 2b - (2,m) Phantom Slot Sample Path 8 3 A Schedule

Comparison of 3D Echocardiogram-Derived 3D Printed Valve Models to Molded Models for Simulated Repair of Pediatric Atrioventricular Valves.

PubMed

Scanlan, Adam B; Nguyen, Alex V; Ilina, Anna; Lasso, Andras; Cripe, Linnea; Jegatheeswaran, Anusha; Silvestro, Elizabeth; McGowan, Francis X; Mascio, Christopher E; Fuller, Stephanie; Spray, Thomas L; Cohen, Meryl S; Fichtinger, Gabor; Jolley, Matthew A

2018-03-01

Mastering the technical skills required to perform pediatric cardiac valve surgery is challenging in part due to limited opportunity for practice. Transformation of 3D echocardiographic (echo) images of congenitally abnormal heart valves to realistic physical models could allow patient-specific simulation of surgical valve repair. We compared materials, processes, and costs for 3D printing and molding of patient-specific models for visualization and surgical simulation of congenitally abnormal heart valves. Pediatric atrioventricular valves (mitral, tricuspid, and common atrioventricular valve) were modeled from transthoracic 3D echo images using semi-automated methods implemented as custom modules in 3D Slicer. Valve models were then both 3D printed in soft materials and molded in silicone using 3D printed "negative" molds. Using pre-defined assessment criteria, valve models were evaluated by congenital cardiac surgeons to determine suitability for simulation. Surgeon assessment indicated that the molded valves had superior material properties for the purposes of simulation compared to directly printed valves (p < 0.01). Patient-specific, 3D echo-derived molded valves are a step toward realistic simulation of complex valve repairs but require more time and labor to create than directly printed models. Patient-specific simulation of valve repair in children using such models may be useful for surgical training and simulation of complex congenital cases.

Long-term bradycardia caused by atrioventricular block can remodel the canine heart to detect the histamine H1 blocker terfenadine-induced torsades de pointes arrhythmias.

PubMed

Takahara, Akira; Sugiyama, Atsushi; Ishida, Yuko; Satoh, Yoshioki; Wang, Kai; Nakamura, Yuji; Hashimoto, Keitaro

2006-03-01

Although a second-generation histamine H(1) blocker terfenadine induced torsades de pointes (TdP) arrhythmias in patients via the blockade of a rapid component of delayed rectifier K(+) current (I(Kr)), such action of terfenadine has not been detected in previous animal models. We analysed the potential of the canine persistent atrioventricular block heart, a new in vivo proarrhythmia model, to detect a torsadogenic effect of terfenadine of an oral dose of 3 or 30 mg kg(-1). The doses can provide therapeutic to supra-therapeutic plasma concentrations as an anti-histamine. In 2 weeks of bradycardiac heart model, there were no significant changes in any of the electrocardiogram parameters after the administration of both doses of terfenadine. In 4-6 weeks of bradycardiac heart model, the low dose of terfenadine hardly affected any of the electrocardiogram parameters except that it induced TdP in one out of six animals. The high dose significantly decreased the atrial rate and ventricular rate, prolonged the QT interval, and induced TdP in five out of six animals. Moreover, temporal variability of repolarization increased after the high-dose administration. These results suggest that long-term bradycardia caused by atrioventricular block can remodel the canine heart to detect terfenadine-induced TdP.

Magnetic navigation in adults with atrial isomerism (heterotaxy syndrome) and supraventricular arrhythmias.

PubMed

Suman-Horduna, Irina; Babu-Narayan, Sonya V; Ueda, Akiko; Mantziari, Lilian; Gujic, Marko; Marchese, Procolo; Dimopoulos, Konstantinos; Gatzoulis, Michael A; Rigby, Michael L; Ho, Siew Yen; Ernst, Sabine

2013-06-01

We analysed the type and mechanism of supraventricular arrhythmias encountered in a series of symptomatic adults with atrial isomerism undergoing catheter ablation procedures. The study population included consecutive adults with atrial isomerism who had previously undergone surgical repair or palliation of the associated anomalies. Patients underwent electrophysiological study for symptomatic arrhythmia in our institution between 2010 and 2012 using magnetic navigation in conjunction with CARTO RMT and three-dimensional (3D) image integration. Eight patients (five females) with a median age of 33 years [interquartile range (IQR) 24-39] were studied. Access to the cardiac chambers of interest was obtained retrogradely via the aorta using remotely navigated magnetic catheters in six patients. Radiofrequency ablation successfully targeted twin atrioventricular (AV) nodal reentrant tachycardia in two patients, atrial fibrillation (AF) in three, focal atrial tachycardia (AT) mainly originating in the left-sided atrium in four patients, and macro-reentrant AT dependent on a right-sided inferior isthmus in three patients. The median fluoroscopy time was 3.0 min (IQR 2-11). After a median follow-up of 10 months (IQR 6-21), five of the ablated patients are free from arrhythmia; two patients experienced episodes of self-terminated AF and AT, respectively, within one month post-ablation; the remaining patient had only non-sustained AT during the electrophysiological study and was managed medically. Various supraventricular tachycardia mechanisms are possible in adults with heterotaxy syndrome, all potentially amenable to radiofrequency ablation. The use of remote magnetic navigation along with 3D mapping facilitated the procedures and resulted in a short radiation time.

[Total cavopulmonary connection for grown diminutive pulmonary artery after staged Blalock-Taussig shunt].

PubMed

Uchita, S; Matsuo, K; Ishida, T; Okajima, Y; Aotsuka, H; Fujiwara, T

1998-11-01

We report a two-year-old girl with asplenia, [A, L, L] DORV, pulmonary atresia, common AV valve, PDA, and TAPVC, who successfully underwent total cavo pulmonary connection (TCPC). Deep cyanosis was pointed out since birth. Cardiac catheterization performed on the sixth day after birth revealed a diminutive pulmonary artery tree of which PA index was 41 mm2/m2. Left modified Blalock-Taussig shunt was created at 27 days of age. The PA index increased to 282 mm2/mm2, but disparity in diameter between the left and the right pulmonary artery was yielded by PDA subsidence. Therefore additional contralateral B-T shunt was made at one year of age. Follow-up cardiac catheterization at 28 months of age showed well developed pulmonary artery; PA index of 460 mm2/m2, right pulmonary resistance (Rp) of 3.49 units, left Rp of 2.33 units, and estimated total Rp was 1.39. According to study, bidirectional Glenn procedure or TCPC was indicated. Considering necessity of urgent repair of common pulmonary vein obstruction, regurgitation of the common atrio-ventricular valve and pulmonary artery stenosis, TCPC was performed with concomitant repair of the associated lesions. Severe butterfly-figure stenosis of the central PA was augmented by anastomosing both the left SVC and the left-sided atrium. In conclusion, diminutive pulmonary artery could be adequately grown by phase-in Blalock-Taussig shunts. Pulmonary blood flow scintigraphy was thought to be useful for estimation of pulmonary resistance in such cases with different pulmonary resistance between right and left PA.

Anodal right ventricular capture during left ventricular stimulation in CRT-implantable cardioverter defibrillators.

PubMed

Thibault, Bernard; Roy, Denis; Guerra, Peter G; Macle, Laurent; Dubuc, Marc; Gagné, Pierre; Greiss, Isabelle; Novak, Paul; Furlani, Aldo; Talajic, Mario

2005-07-01

Cardiac resynchronization therapy (CRT) has been shown to improve symptoms of patients with moderate to severe heart failure. Optimal CRT involves biventricular or left ventricular (LV) stimulation alone, atrio-ventricular (AV) delay optimization, and possibly interventricular timing adjustment. Recently, anodal capture of the right ventricle (RV) has been described for patients with CRT-pacemakers. It is unknown whether the same phenomenon exists in CRT systems associated with defibrillators (CRT-ICD). The RV leads used in these systems are different from pacemaker leads: they have a larger diameter and shocking coils, which may affect the occurrence of anodal capture. We looked for anodal RV capture during LV stimulation in 11 consecutive patients who received a CRT-ICD system with RV leads with a true bipolar design. Fifteen patients who had RV leads with an integrated design were used as controls. Anodal RV and LV thresholds were determined at pulse width (pw) durations of 0.2, 0.5, and 1.0 ms. RV anodal capture during LV pacing was found in 11/11 patients at some output with true bipolar RV leads versus 0/15 patients with RV leads with an integrated bipolar design. Anodal RV capture threshold was more affected by changes in pw duration than LV capture threshold. In CRT-ICD systems, RV leads with a true bipolar design with the proximal ring also used as the anode for LV pacing are associated with a high incidence of anodal RV capture during LV pacing. This may affect the clinical response to alternative resynchronization methods using single LV stimulation or interventricular delay programming.

3D characterization of EMT cell density in developing cardiac cushions using optical coherence tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Yu, Siyao; Gu, Shi; Zhao, Xiaowei; Liu, Yehe; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

2017-02-01

Congenital heart defects (CHDs) are the most common birth defect, affecting between 4 and 75 per 1,000 live births depending on the inclusion criteria. Many of these defects can be traced to defects of cardiac cushions, critical structures during development that serve as precursors to many structures in the mature heart, including the atrial and ventricular septa, and all four sets of cardiac valves. Epithelial-mesenchymal transition (EMT) is the process through which cardiac cushions become populated with cells. Altered cushion size or altered cushion cell density has been linked to many forms of CHDs, however, quantitation of cell density in the complex 3D cushion structure poses a significant challenge to conventional histology. Optical coherence tomography (OCT) is a technique capable of 3D imaging of the developing heart, but typically lacks the resolution to differentiate individual cells. Our goal is to develop an algorithm to quantitatively characterize the density of cells in the developing cushion using 3D OCT imaging. First, in a heart volume, the atrioventricular (AV) cushions were manually segmented. Next, all voxel values in the region of interest were pooled together to generate a histogram. Finally, two populations of voxels were classified using either K-means classification, or a Gaussian mixture model (GMM). The voxel population with higher values represents cells in the cushion. To test the algorithm, we imaged and evaluated avian embryonic hearts at looping stages. As expected, our result suggested that the cell density increases with developmental stages. We validated the technique against scoring by expert readers.

Role of aminophylline in refractory heart failure: a comparison to the vasodilator sodium nitroprusside, the old and the new.

PubMed

DiBianco, R; Rosenfeld, S P; Katz, R J; Simpson, A G; Fletcher, R D; Singh, S

1980-08-01

Aminophylline [(theophylline ethylene diamine (TED)] reportedly improved cardiac hemodynamics by lowering vascular resistances and increasing contractility. TED as used clinically has not been compared to the vasodilator sodium nitroprusside (NP). To assess the relative hemodynamic effects of these two commonly used agents, the following comparison was made. Ten patients with congestive cardiomyopathy in chronic refractory heart failure [New York Heart Association (NYHA) class IV] were studied. All patients demonstrated cardiomegaly by chest x ray and echocardiography (LVd = 6.3 +/- 0.7 cm) and markedly abnormal hemodynamics during baseline observations (see Table I). Hemodynamic measurements at baseline were compared after TED infusion (mean blood level = 16 +/- 12 micrograms/m/TED) and during intravenous NP. No significant changes in heart rate occurred during either therapeutic intervention; a fall in mean arterial pressure of 10 mmHg (p < 0.01) was observed during NP therapy; atrioventricular (AV) block with ventricular fibrillation was successfully treated in one patient after TED. Theophylline ethylene diamine demonstrated no detectable cardiac hemodynamic effects 60--90 min post infusion despite proven blood levels, whereas NP exhibited distinctly beneficial effects in this patient group. Previous studies demonstrating improved hemodynamics occurring with TED have been limited to the time of infusion or within the following 40 min, a time when TED blood levels are maximum and therefore closest to toxicity. The results of this study suggest that TED demonstrates no beneficial hemodynamic effects in refractory heart failure as early as 1 h after infusion despite blood levels in the therapeutic range.

Sympathoinhibition and hypotension in carotid sinus hypersensitivity

NASA Technical Reports Server (NTRS)

Smith, M. L.; Ellenbogen, K. A.; Eckberg, D. L.

1992-01-01

Carotid sinus reflex hypersensitivity is a known cause of syncope in humans. The condition is characterized by cardioinhibition and vasodepression, each to varying degrees. The extent and importance of sympathoinhibition has not been determined in patients with carotid sinus hypersensitivity. This study reports on the extent of sympathoinhibition measured directly directly during carotid massage with and without atrioventricular sequential pacing, in a patient with symptomatic carotid sinus reflex hypersensitivity. Carotid massage elicited asystole, hypotension and complete inhibition of muscle sympathetic nerve activity. Carotid massage during atrioventricular pacing produced similar sympathoinhibition, but with minimal hypotension. Therefore, sympathoinhibition did not contribute importantly to the hypotension during carotid massage in the supine position in this patient. Further investigations are required to elucidate the relation of sympathoinhibition to hypotension in patients with carotid sinus hypersensitivity in the upright position.

Atrioventricular junction (AVJ) motion tracking: a software tool with ITK/VTK/Qt.

PubMed

Pengdong Xiao; Shuang Leng; Xiaodan Zhao; Hua Zou; Ru San Tan; Wong, Philip; Liang Zhong

2016-08-01

The quantitative measurement of the Atrioventricular Junction (AVJ) motion is an important index for ventricular functions of one cardiac cycle including systole and diastole. In this paper, a software tool that can conduct AVJ motion tracking from cardiovascular magnetic resonance (CMR) images is presented by using Insight Segmentation and Registration Toolkit (ITK), The Visualization Toolkit (VTK) and Qt. The software tool is written in C++ by using Visual Studio Community 2013 integrated development environment (IDE) containing both an editor and a Microsoft complier. The software package has been successfully implemented. From the software engineering practice, it is concluded that ITK, VTK, and Qt are very handy software systems to implement automatic image analysis functions for CMR images such as quantitative measure of motion by visual tracking.

Facts about Truncus Arteriosis

MedlinePlus

... Septal Defect Atrioventricular Septal Defect Coarctation of the Aorta D-Transposition of the Great Arteries Hypoplastic Left ... usual two vessels (the main pulmonary artery and aorta ). What is Truncus Arteriosus Click here to view ...

Impact of Ischemic and Valvular Heart Disease on Atrial Excitation:A High-Resolution Epicardial Mapping Study.

PubMed

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

2018-03-08

The influence of underlying heart disease or presence of atrial fibrillation (AF) on atrial excitation during sinus rhythm (SR) is unknown. We investigated atrial activation patterns and total activation times of the entire atrial epicardial surface during SR in patients with ischemic and/or valvular heart disease with or without AF. Intraoperative epicardial mapping (N=128/192 electrodes, interelectrode distances: 2 mm) of the right atrium, Bachmann's bundle (BB), left atrioventricular groove, and pulmonary vein area was performed during SR in 253 patients (186 male [74%], age 66±11 years) with ischemic heart disease (N=132, 52%) or ischemic valvular heart disease (N=121, 48%). As expected, SR origin was located at the superior intercaval region of the right atrium in 232 patients (92%). BB activation occurred via 1 wavefront from right-to-left (N=163, 64%), from the central part (N=18, 7%), or via multiple wavefronts (N=72, 28%). Left atrioventricular groove activation occurred via (1) BB: N=108, 43%; (2) pulmonary vein area: N=9, 3%; or (3) BB and pulmonary vein area: N=136, 54%; depending on which route had the shortest interatrial conduction time ( P <0.001). Ischemic valvular heart disease patients more often had central BB activation and left atrioventricular groove activation via pulmonary vein area compared with ischemic heart disease patients (N=16 [13%] versus N=2 [2%]; P =0.009 and N=86 [71%] versus N=59 [45%]; P <0.001, respectively). Total activation times were longer in patients with AF (AF: 136±20 [92-186] ms; no AF: 114±17 [74-156] ms; P <0.001), because of prolongation of right atrium ( P =0.018) and BB conduction times ( P <0.001). Atrial excitation during SR is affected by underlying heart disease and AF, resulting in alternative routes for BB and left atrioventricular groove activation and prolongation of total activation times. Knowledge of atrial excitation patterns during SR and its electropathological variations, as demonstrated in this study, is essential to further unravel the pathogenesis of AF. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Left cardiac isomerism in the Sonic hedgehog null mouse.

PubMed

Hildreth, Victoria; Webb, Sandra; Chaudhry, Bill; Peat, Jonathan D; Phillips, Helen M; Brown, Nigel; Anderson, Robert H; Henderson, Deborah J

2009-06-01

Sonic hedgehog (Shh) is a secreted morphogen necessary for the production of sidedness in the developing embryo. In this study, we describe the morphology of the atrial chambers and atrioventricular junctions of the Shh null mouse heart. We demonstrate that the essential phenotypic feature is isomerism of the left atrial appendages, in combination with an atrioventricular septal defect and a common atrioventricular junction. These malformations are known to be frequent in humans with left isomerism. To confirm the presence of left isomerism, we show that Pitx2c, a recognized determinant of morphological leftness, is expressed in the Shh null mutants on both the right and left sides of the inflow region, and on both sides of the solitary arterial trunk exiting from the heart. It has been established that derivatives of the second heart field expressing Isl1 are asymmetrically distributed in the developing normal heart. We now show that this population is reduced in the hearts from the Shh null mutants, likely contributing to the defects. To distinguish the consequences of reduced contributions from the second heart field from those of left-right patterning disturbance, we disrupted the movement of second heart field cells into the heart by expressing dominant-negative Rho kinase in the population of cells expressing Isl1. This resulted in absence of the vestibular spine, and presence of atrioventricular septal defects closely resembling those seen in the hearts from the Shh null mutants. The primary atrial septum, however, was well formed, and there was no evidence of isomerism of the atrial appendages, suggesting that these features do not relate to disruption of the contributions made by the second heart field. We demonstrate, therefore, that the Shh null mouse is a model of isomerism of the left atrial appendages, and show that the recognized associated malformations found at the venous pole of the heart in the setting of left isomerism are likely to arise from the loss of the effects of Shh in the establishment of laterality, combined with a reduced contribution made by cells derived from the second heart field.

Left Atrial Remodeling and Atrioventricular Coupling in a Canine Model of Early Heart Failure With Preserved Ejection Fraction

PubMed Central

Zakeri, Rosita; Moulay, Gilles; Chai, Qiang; Ogut, Ozgur; Hussain, Saad; Takahama, Hiroyuki; Lu, Tong; Wang, Xiao-Li; Linke, Wolfgang A.; Lee, Hon-Chi; Redfield, Margaret M.

2016-01-01

Background Left atrial (LA) compliance and contractility influence left ventricular (LV) stroke volume. We hypothesized that diminished LA compliance and contractile function occur early during development of heart failure with preserved ejection fraction (HFpEF) and impair overall cardiac performance. Method and Results Cardiac magnetic resonance imaging, echocardiography, LV and LA pressure-volume studies, and tissue analyses were performed in a model of early HFpEF (elderly dogs, renal wrap-induced hypertension, exogenous aldosterone; n=9) and young control dogs (sham surgery; n=13). Early HFpEF was associated with LA enlargement, cardiomyocyte hypertrophy and enhanced LA contractile function (median active emptying fraction 16% [95% CI 13–24] vs 12[10–14]%, p=0.008; end-systolic pressure-volume relationship slope 2.4[1.9–3.2]mmHg/mL HFpEF vs 1.5[1.2–2.2]mmHg/mL controls, p=0.01). However, atrioventricular coupling was impaired and the curvilinear LA end-reservoir pressure-volume relationship was shifted upward/leftward in HFpEF (LA stiffness constant, βLA, 0.16[0.11–0.18]mmHg/mL vs 0.06[0.04–0.10]mmHg/mL controls, p=0.002) indicating reduced LA compliance. Impaired atrioventricular coupling and lower LA compliance correlated with lower LV stroke volume. Total fibrosis and titin isoform composition were similar between groups, however titin was hyperphosphorylated in HFpEF and correlated with βLA. LA microvascular reactivity was diminished in HFpEF versus controls. LA microvascular density tended to be lower in HFpEF and inversely correlated with βLA. Conclusions In early-stage hypertensive HFpEF, LA cardiomyocyte hypertrophy, titin hyperphosphorylation and microvascular dysfunction occur in association with increased systolic and diastolic LA chamber stiffness, impaired atrioventricular coupling and decreased LV stroke volume. These data indicate that maladaptive LA remodeling occurs early during HFpEF development, supporting a concept of global myocardial remodeling. PMID:27758811

Four-dimensional ultrasonography of the fetal heart with spatiotemporal image correlation.

PubMed

Gonçalves, Luís F; Lee, Wesley; Chaiworapongsa, Tinnakorn; Espinoza, Jimmy; Schoen, Mary Lou; Falkensammer, Peter; Treadwell, Marjorie; Romero, Roberto

2003-12-01

This study was undertaken to describe a new technique for the examination of the fetal heart using four-dimensional ultrasonography with spatiotemporal image correlation (STIC). Volume data sets of the fetal heart were acquired with a new cardiac gating technique (STIC), which uses automated transverse and longitudinal sweeps of the anterior chest wall. These volumes were obtained from 69 fetuses: 35 normal, 16 with congenital anomalies not affecting the cardiovascular system, and 18 with cardiac abnormalities. Dynamic multiplanar slicing and surface rendering of cardiac structures were performed. To illustrate the STIC technique, two representative volumes from a normal fetus were compared with volumes obtained from fetuses with the following congenital heart anomalies: atrioventricular septal defect, tricuspid stenosis, tricuspid atresia, and interrupted inferior vena cava with abnormal venous drainage. Volume datasets obtained with a transverse sweep were utilized to demonstrate the cardiac chambers, moderator band, interatrial and interventricular septae, atrioventricular valves, pulmonary veins, and outflow tracts. With the use of a reference dot to navigate the four-chamber view, intracardiac structures could be simultaneously studied in three orthogonal planes. The same volume dataset was used for surface rendering of the atrioventricular valves. The aortic and ductal arches were best visualized when the original plane of acquisition was sagittal. Volumes could be interactively manipulated to simultaneously visualize both outflow tracts, in addition to the aortic and ductal arches. Novel views of specific structures were generated. For example, the location and extent of a ventricular septal defect was imaged in a sagittal view of the interventricular septum. Furthermore, surface-rendered images of the atrioventricular valves were employed to distinguish between normal and pathologic conditions. Representative video clips were posted on the Journal's Web site to demonstrate the diagnostic capabilities of this new technique. Dynamic multiplanar slicing and surface rendering of the fetal heart are feasible with STIC technology. One good quality volume dataset, obtained from a transverse sweep, can be used to examine the four-chamber view and the outflow tracts. This novel method may assist in the evaluation of fetal cardiac anatomy.

Regulation of Long-Chain N-Acyl-Homoserine Lactones in Agrobacterium vitis

PubMed Central

Hao, Guixia; Burr, Thomas J.

2006-01-01

Homologs of quorum-sensing luxR and luxI regulatory genes, avsR and avsI, were identified in Agrobacterium vitis strain F2/5. Compared to other LuxI proteins from related species, the deduced AvsI shows the greatest identity to SinI (71%) from Sinorhizobium meliloti Rm1021. AvsR possesses characteristic autoinducer binding and helix-turn-helix DNA binding domains and shares a high level of identity with SinR (38%) from Rm1021. Site-directed mutagenesis of avsR and avsI was performed, and both genes are essential for hypersensitive-like response (HR) and necrosis. Two hypothetical proteins (ORF1 and ORF2) that are positioned downstream of avsR-avsI are also essential for the phenotypes. Profiles of N-acyl-homoserine lactones (AHLs) isolated from the wild type and mutants revealed that disruption of avsI, ORF1, or ORF2 abolished the production of long-chain AHLs. Disruption of avsR reduces long-chain AHLs. Expression of a cloned avsI gene in A. tumefaciens strain NT1 resulted in synthesis of long-chain AHLs. The necrosis and HR phenotypes of the avsI and avsR mutants were fully complemented with cloned avsI. The addition of synthetic AHLs (C16:1 and 3-O-C16:1) complemented grape necrosis in the avsR, avsI, ORF1, and ORF2 mutants. It was determined by reverse transcriptase PCR that the expression level of avsI is regulated by avsR but not by aviR or avhR, two other luxR homologs which were previously shown to be associated with induction of a tobacco hypersensitive response and grape necrosis. We further verified that avsR regulates avsI by measuring the expression of an avsI::lacZ fusion construct. PMID:16513747

Birth Defects Data and Statistics

MedlinePlus

... Septal Defect Atrioventricular Septal Defect Coarctation of the Aorta D-Transposition of the Great Arteries Hypoplastic Left ... Syndrome Disorders Gastroschisis Heart Defects Coarctation of the Aorta Hypoplastic left heart syndrome Tetralogy of Fallot Other ...

Facts about Hypoplastic Left Heart Syndrome

MedlinePlus

... Septal Defect Atrioventricular Septal Defect Coarctation of the Aorta D-Transposition of the Great Arteries Hypoplastic Left ... is very small. The ascending portion of the aorta is underdeveloped or is too small. Often, babies ...

Valvulopathy consistent with endocarditis in an Argentine boa (Boa constrictor occidentalis).

PubMed

Wernick, Morena B; Novo-Matos, José; Ebling, Alessia; Kühn, Karolin; Ruetten, Maja; Hilbe, Monika; Howard, Judith; Chang, Rita; Prohaska, Sarah; Hatt, Jean-Michel

2015-03-01

An Argentine boa (Boa constrictor occidentalis) of 5 yr 7 mo of age was presented for respiratory problems and regurgitation. Radiographs revealed evidence of cardiomegaly and pneumonia. Blood smear examination revealed the presence of intracytoplasmic inclusion bodies in peripheral lymphocytes, consistent with inclusion body disease. Cultures of a tracheal wash sample resulted in growth of Ochrobactrum intermedium and Pseudomonas putida. Echocardiographic examination revealed a large vegetative lesion on the right atrioventricular valve with valvular insufficiency, a mildly dilated right atrium, and pulmonary hypertension. Postmortem examination confirmed the presence of pneumonia and bacterial endocarditis with dystrophic mineralization of the right atrioventricular valve, associated with different bacteria than those cultured from the tracheal wash. The present case is the first report of endocarditis in a boa constrictor and contributes to the rare reports of cardiac disease in snakes.

Early and late arrhythmogenic effects of doxorubicin.

PubMed

Kilickap, Saadettin; Barista, Ibrahim; Akgul, Ebru; Aytemir, Kudret; Aksoy, Sercan; Tekuzman, Gulten

2007-03-01

To determine the incidence of early and late arrhythmogenic effects of doxorubicin-containing chemotherapy regimens. A prospective study including 29 patients who were treated with doxorubicin-containing regimens. Cardiac evaluation was based on 24-hour electrocardiographic monitorization (Holter), which was performed during the first cycle of doxorubicin-containing regimens, as well as after the last cycle of chemotherapy. The mean age of the patients was 45.8 +/- 15.1 (range 18-69). Holter records obtained during the first cycle of treatment revealed varying arrhythmias in 19 patients (65.5%) and in 18 (62.1%) patients after completion of therapy. One patient presented with syncope and both Mobitz Type 2 atrioventricular block and complete atrioventricular block were demonstrated. The patient subsequently underwent permanent pacemaker implantation. Doxorubicin may result in arrhythmias both in early and late periods of treatment. These arrhythmias are rarely life threatening.

Life-threatening Arrhythmias in a Becker Muscular Dystrophy Family due to the Duplication of Exons 3-4 of the Dystrophin Gene.

PubMed

Ishizaki, Masatoshi; Fujimoto, Akiko; Ueyama, Hidetsugu; Nishida, Yasuto; Imamura, Shigehiro; Uchino, Makoto; Ando, Yukio

2015-01-01

We herein present a report of three patients with Becker muscular dystrophy in the same family who developed complete atrioventricular block or ventricular tachycardia with severe cardiomyopathy. Our cases became unable to walk in their teens, and were introduced to mechanical ventilation due to respiratory muscle weakness in their twenties and thirties. In all three cases, a medical device such as a permanent cardiac pacemaker or an implantable cardiac defibrillator was considered to be necessary. The duplication of exons 3-4 in the dystrophin gene was detected in two of the patients. In patients with Becker muscular dystrophy, complete atrioventricular block or ventricular tachycardia within a family has rarely been reported. Thus attention should be paid to the possibility of severe arrhythmias in the severe phenotype of Becker muscular dystrophy.

Complex phenotype linked to a mutation in exon 11 of the lamin A/C gene: Hypertrophic cardiomyopathy, atrioventricular block, severe dyslipidemia and diabetes.

PubMed

Francisco, Ana Rita G; Santos Gonçalves, Inês; Veiga, Fátima; Mendes Pedro, Mónica; Pinto, Fausto J; Brito, Dulce

2017-09-01

The lamin A/C (LMNA) gene encodes lamins A and C, which have an important role in nuclear cohesion and chromatin organization. Mutations in this gene usually lead to the so-called laminopathies, the primary cardiac manifestations of which are dilated cardiomyopathy and intracardiac conduction defects. Some mutations, associated with lipodystrophy but not cardiomyopathy, have been linked to metabolic abnormalities such as diabetes and severe dyslipidemia. Herein we describe a new phenotype associated with a mutation in exon 11 of the LMNA gene: hypertrophic cardiomyopathy, atrioventricular block, severe dyslipidemia and diabetes. A 64-year-old woman with hypertrophic cardiomyopathy and a point mutation in exon 11 of the LMNA gene (c.1718C>T, Ser573Leu) presented with severe symptomatic ventricular hypertrophy and left ventricular outflow tract obstruction. She underwent septal alcohol ablation, followed by Morrow myectomy. The patient was also diagnosed with severe dyslipidemia, diabetes and obesity, and fulfilled diagnostic criteria for metabolic syndrome. No other characteristics of LMNA mutation-related phenotypes were identified. The development of type III atrioventricular block with no apparent cause, and mildly depressed systolic function, prompted referral for cardiac resynchronization therapy. In conclusion, the association between LMNA mutations and different phenotypes is complex and not fully understood, and can present with a broad spectrum of severity. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Exclusive double outlet right ventricle with atrioventricular concordance and pulmonary stenosis. Results of reconstructive surgery.

PubMed

Busquet, J; Fontan, F; Choussat, A; Caianiello, G; Fernandez, G

1988-01-01

Double outlet right ventricle associated with atrioventricular concordance, pulmonary stenosis and situs solitus of the atria is a subset of double outlet right ventricle related through the surgical treatment. From 1974 to 1985, 14 patients, 5 males, 9 females (mean age 8.9 years, range 13 months-22 years) were operated upon. All patients had infundibular stenosis and normal or large pulmonary arteries. The apex of the heart was to the right in 2 patients, the right and left ventricles were superior and inferior in 2 patients and 1 patient had both anomalies. The ventricular septal defect was subaortic in 11 patients (aorto-mitral discontinuity in 5) and non-committed in 3 patients. Three patients had 2 ventricular septal defects. The aorta was anterior in 3 patients and to the right of the pulmonary artery in 11 patients. All patients, through a transventricular and transatrial approach, had a reconstructive surgery. In 3 patients, an aortic homograft valved conduit was used. One patient had the ventricular septal defect enlarged. There was one early death (7.1%) from high residual right ventricle pressure and no late death. One patient had a transient atrioventricular block. One patient was reoperated upon for a residual ventricular septal defect. All survivors had a good clinical result. Re-evaluation in 8 patients confirmed excellent haemodynamics: the right ventricle to pulmonary artery pressure gradient decreased from 80 mm Hg (range 60-95) preoperatively to 24 mm Hg (range 3-32) postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-outlet right ventricle revisited.

PubMed

Ebadi, Ameneh; Spicer, Diane E; Backer, Carl L; Fricker, F Jay; Anderson, Robert H

2017-08-01

Double-outlet right ventricle is a form of ventriculoarterial connection. The definition formulated by the International Society for Nomenclature of Paediatric and Congenital Heart Disease is based on hearts with both arterial trunks supported in their greater part by a morphologically right ventricle. Bilateral infundibula and ventricular septal defects are highly debated criteria. This study examines the anatomic controversies surrounding double-outlet right ventricle. We show that hearts with double-outlet right ventricle can have atrioventricular-to-arterial valvular continuity. We emphasize the difference between the interventricular communication and the zone of deficient ventricular septation. The hearts examined were from the University of Florida in Gainesville; Johns Hopkins All Children's Hospital, St Petersburg, Fla; and Lurie Children's Hospital, Chicago, Ill. Each specimen had at least 75% of both arterial roots supported by the morphologically right ventricle, with a total of 100 hearts examined. The morphologic method was used to assess anatomic features, including arterial-atrioventricular valvular continuity, subarterial infundibular musculature, and the location of the hole between the ventricles. Most hearts had fibrous continuity between one of the arterial valves and an atrioventricular valve, with bilateral infundibula in 23%, and intact ventricular septum in 5%. Bilateral infundibula are not a defining feature of double-outlet right ventricle, representing only 23% of the specimens in our sample. The interventricular communication can have a posteroinferior muscular rim or extend to become perimembranous (58%). Double-outlet right ventricle can exist with an intact ventricular septum. Copyright © 2017 The American Association for Thoracic Surgery. All rights reserved.

[Comparison of atrio-ventricular and total cavo-pulmonary connections versus atrio-pulmonary anastomosis for repair of tricuspid atresia in dogs].

PubMed

Yu, C; Liu, Y; Zhu, X; Li, Y; Li, Y

2000-03-01

To compare the hemodynamic effect and energy loss of atrio-ventricular and total cavo-pulmonary connections versus atrio-pulmonary anastomosis for modified Fontan in dogs. Fifteen adult mongrel dogs were divided into three groups. Group I underwent right atrium to right ventricle (using 50% and 25% right ventricular chamber, respectively) connection with the flap of valved homo-pulmonary artery (modified Bjoerk procedure). Group II underwent total cavo-pulmonary connection. Group III received atrio-pulmonary anastomosis. Right atrium pressure, pulmonary artery pressure, and cardiac output were measured by Swan-Ganz catheter. The volumes of the right pulmonary artery, left pulmonary artery, superior vena cava and inferior vena cava were measured by electromagnetic flowmeter. The flow-rate of the right pulmonary artery, left pulmonary artery, superior vena cava and inferior vena cava were measured echocardiographically. The fluid energy loss was calculated. The postoperative right atrium pressure in group I was lower than in group III (P < 0.05). The postoperative stroke index in group I and group II was higher than in group III (P < 0.01). The fluid energy loss was decreased when 50% or 25% right ventricle chamber was used (P < 0.01) and the fluid energy less in group II was less than in group III. Our experience suggested that atrio-ventricular connection and total cavo-pulmonary connection would be better than atrio-pulmonary anastomosis for modified Fontan repair of tricuspid valve atresia.

Influence of CHDs on psycho-social and neurodevelopmental outcomes in children with Down syndrome.

PubMed

Visootsak, Jeannie; Huddleston, Lillie; Buterbaugh, Allison; Perkins, Adrienne; Sherman, Stephanie; Hunter, Jessica

2016-02-01

To evaluate the family psycho-social outcomes of children with Down syndrome and atrioventricular septal defect, and examine the impact of these variables on the child's neurodevelopmental outcome. This was a cross-sectional study that consisted of 57 children with Down syndrome - 20 cases and 37 controls - of ~12-14 months of age. In both groups, we assessed the development of the child, the quality of the child's home environment, and parenting stress. Compared with the Down syndrome without CHD group, the atrioventricular septal defect group revealed lower scores in all developmental domains, less optimal home environments, and higher parental stress. Significant differences in development were seen in the areas of cognition (p=0.04), expressive language (p=0.05), and gross motor (p<0.01). The Home Observation for Measurement of the Environment revealed significant differences in emotional and verbal responsiveness of the mother between the two groups. The Parenting Stress Index revealed that the Down syndrome with atrioventricular septal defect group had a significantly higher child demandingness subdomain scores compared with the Down syndrome without CHD group. The diagnosis of a CHD in addition to the diagnosis of Down syndrome may provide additional stress to the child and parents, elevating parental concern and disrupting family dynamics, resulting in further neurodevelopmental deficits. Finding that parental stress and home environment may play a role in the neurodevelopmental outcomes may prompt new family-directed interventions and anticipatory guidance for the families of children with Down syndrome who have a CHD.

Zebrafish heart as a model to study the integrative autonomic control of pacemaker function

PubMed Central

Stoyek, Matthew R.; Quinn, T. Alexander; Croll, Roger P.

2016-01-01

The cardiac pacemaker sets the heart's primary rate, with pacemaker discharge controlled by the autonomic nervous system through intracardiac ganglia. A fundamental issue in understanding the relationship between neural activity and cardiac chronotropy is the identification of neuronal populations that control pacemaker cells. To date, most studies of neurocardiac control have been done in mammalian species, where neurons are embedded in and distributed throughout the heart, so they are largely inaccessible for whole-organ, integrative studies. Here, we establish the isolated, innervated zebrafish heart as a novel alternative model for studies of autonomic control of heart rate. Stimulation of individual cardiac vagosympathetic nerve trunks evoked bradycardia (parasympathetic activation) and tachycardia (sympathetic activation). Simultaneous stimulation of both vagosympathetic nerve trunks evoked a summative effect. Effects of nerve stimulation were mimicked by direct application of cholinergic and adrenergic agents. Optical mapping of electrical activity confirmed the sinoatrial region as the site of origin of normal pacemaker activity and identified a secondary pacemaker in the atrioventricular region. Strong vagosympathetic nerve stimulation resulted in a shift in the origin of initial excitation from the sinoatrial pacemaker to the atrioventricular pacemaker. Putative pacemaker cells in the sinoatrial and atrioventricular regions expressed adrenergic β2 and cholinergic muscarinic type 2 receptors. Collectively, we have demonstrated that the zebrafish heart contains the accepted hallmarks of vertebrate cardiac control, establishing this preparation as a viable model for studies of integrative physiological control of cardiac function by intracardiac neurons. PMID:27342878

Left ventricular long-axis function in treated haemochromatosis.

PubMed

Davidsen, Einar Skulstad; Hervig, Tor; Omvik, Per; Gerdts, Eva

2009-03-01

We recently demonstrated reduced exercise capacity in treated genetic haemochromatosis, in spite of normal radial left ventricular (LV) systolic function assessed by 2-dimensional echocardiography at rest. It remains unknown if haemochromatosis-related impairment of LV long-axis function can be demonstrated also at rest. LV long-axis function was assessed by echocardiography including spectral tissue Doppler of systolic (S') and early (E') diastolic velocities in 105 treated haemochromatosis patients and 50 controls. Patients had higher body mass index, systolic atrioventricular excursion, and smaller LV end-systolic diameter (all P < 0.05). Other conventional echocardiographic variables did not differ. S' was normal in both groups, though significantly higher among the patients (11.1 vs. 9.9 cm/s, P < 0.001). In multiple regression analysis, higher S' was associated with having haemochromatosis, independently of significant contributions from higher atrioventricular excursion and LV length, and lower body mass index and E/E'-ratio (multiple R(2) = 0.44, P < 0.001). E' did not differ between patients and controls. However, in multivariate analysis lower E' was associated with having haemochromatosis independently of significant contributions from higher age and diastolic blood pressure, and lower transmitral E and end-diastolic LV length (multiple R(2) = 0.57, P < 0.001). The long-axis function in the haemochromatosis group was normal. Still haemochromatosis, even in this group of patients treated with regular phlebotomy, influenced both systolic and early diastolic long-axis function, and was associated with higher atrioventricular excursion and S', and with lower E'.

Common and Rare Coding Genetic Variation Underlying the Electrocardiographic PR Interval.

PubMed

Lin, Honghuang; van Setten, Jessica; Smith, Albert V; Bihlmeyer, Nathan A; Warren, Helen R; Brody, Jennifer A; Radmanesh, Farid; Hall, Leanne; Grarup, Niels; Müller-Nurasyid, Martina; Boutin, Thibaud; Verweij, Niek; Lin, Henry J; Li-Gao, Ruifang; van den Berg, Marten E; Marten, Jonathan; Weiss, Stefan; Prins, Bram P; Haessler, Jeffrey; Lyytikäinen, Leo-Pekka; Mei, Hao; Harris, Tamara B; Launer, Lenore J; Li, Man; Alonso, Alvaro; Soliman, Elsayed Z; Connell, John M; Huang, Paul L; Weng, Lu-Chen; Jameson, Heather S; Hucker, William; Hanley, Alan; Tucker, Nathan R; Chen, Yii-Der Ida; Bis, Joshua C; Rice, Kenneth M; Sitlani, Colleen M; Kors, Jan A; Xie, Zhijun; Wen, Chengping; Magnani, Jared W; Nelson, Christopher P; Kanters, Jørgen K; Sinner, Moritz F; Strauch, Konstantin; Peters, Annette; Waldenberger, Melanie; Meitinger, Thomas; Bork-Jensen, Jette; Pedersen, Oluf; Linneberg, Allan; Rudan, Igor; de Boer, Rudolf A; van der Meer, Peter; Yao, Jie; Guo, Xiuqing; Taylor, Kent D; Sotoodehnia, Nona; Rotter, Jerome I; Mook-Kanamori, Dennis O; Trompet, Stella; Rivadeneira, Fernando; Uitterlinden, André; Eijgelsheim, Mark; Padmanabhan, Sandosh; Smith, Blair H; Völzke, Henry; Felix, Stephan B; Homuth, Georg; Völker, Uwe; Mangino, Massimo; Spector, Timothy D; Bots, Michiel L; Perez, Marco; Kähönen, Mika; Raitakari, Olli T; Gudnason, Vilmundur; Arking, Dan E; Munroe, Patricia B; Psaty, Bruce M; van Duijn, Cornelia M; Benjamin, Emelia J; Rosand, Jonathan; Samani, Nilesh J; Hansen, Torben; Kääb, Stefan; Polasek, Ozren; van der Harst, Pim; Heckbert, Susan R; Jukema, J Wouter; Stricker, Bruno H; Hayward, Caroline; Dörr, Marcus; Jamshidi, Yalda; Asselbergs, Folkert W; Kooperberg, Charles; Lehtimäki, Terho; Wilson, James G; Ellinor, Patrick T; Lubitz, Steven A; Isaacs, Aaron

2018-05-01

Electrical conduction from the cardiac sinoatrial node to the ventricles is critical for normal heart function. Genome-wide association studies have identified more than a dozen common genetic loci that are associated with PR interval. However, it is unclear whether rare and low-frequency variants also contribute to PR interval heritability. We performed large-scale meta-analyses of the PR interval that included 83 367 participants of European ancestry and 9436 of African ancestry. We examined both common and rare variants associated with the PR interval. We identified 31 genetic loci that were significantly associated with PR interval after Bonferroni correction ( P <1.2×10 -6 ), including 11 novel loci that have not been reported previously. Many of these loci are involved in heart morphogenesis. In gene-based analysis, we found that multiple rare variants at MYH6 ( P =5.9×10 -11 ) and SCN5A ( P =1.1×10 -7 ) were associated with PR interval. SCN5A locus also was implicated in the common variant analysis, whereas MYH6 was a novel locus. We identified common variants at 11 novel loci and rare variants within 2 gene regions that were significantly associated with PR interval. Our findings provide novel insights to the current understanding of atrioventricular conduction, which is critical for cardiac activity and an important determinant of health. © 2018 American Heart Association, Inc.

In vivo hemodynamic and electrocardiographic changes following Crataegus aronia syn. Azarolus L administration to normotensive Wistar rats.

PubMed

Shatoor, Abdullah S

2013-02-01

To evaluate the effects of the whole plant aqueous extract of Crataegus aronia (C. aronia) syn. Azarolus (L) on the hemodynamic and electrocardiographic intervals in albino rats. This study was carried out in 2 stages at the Research Laboratory, Physiology Department, Medical College of King Khalid University, Abha, Kingdom of Saudi Arabia between February and June 2012. First, the effects of C. aronia syn. Azarolus (L) on the hemodynamics and electrocardiograph in 54 Wistar male rats were assessed, then the mechanisms underlying the hemodynamic and electrocardiographic changes observed in the first stage were evaluated in 48 rats of the same species. The C. aronia administered at escalating doses (0.05-20 microgram/kg) produced a dose-time-dependent decrease in heart rate (HR) and mean arterial pressure (MAP). Higher doses (15 and 20 microgram/kg) produced the most significant reduction in both HR and MAP, and induced sinus node suppression and progressive atrio-ventricular blockade. The underlying mechanism of the induced bradyarrhythmia appeared to be due to the direct stimulation of the muscarinic receptor M2 and possible blockade of beta-receptors, while the hypotension was caused by enhanced nitric oxide release. No significant alterations in the electrocardiogram (ECG) components were observed. The administration of the C. aronia syn. Azarolus extract induced bradyarrhythmia and hypotension, without alteration in the ECG components.

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

PubMed

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

2014-01-01

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

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

PubMed Central

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

2014-01-01

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

Brain uptake of a non-radioactive pseudo-carrier and its effect on the biodistribution of [(18)F]AV-133 in mouse brain.

PubMed

Wu, Xianying; Zhou, Xue; Zhang, Shuxian; Zhang, Yan; Deng, Aifang; Han, Jie; Zhu, Lin; Kung, Hank F; Qiao, Jinping

2015-07-01

9-[(18)F]Fluoropropyl-(+)-dihydrotetrabenazine ([(18)F]AV-133) is a new PET imaging agent targeting vesicular monoamine transporter type II (VMAT2). To shorten the preparation of [(18)F]AV-133 and to make it more widely available, a simple and rapid purification method using solid-phase extraction (SPE) instead of high-pressure liquid chromatography (HPLC) was developed. The SPE method produced doses containing the non-radioactive pseudo-carrier 9-hydroxypropyl-(+)-dihydrotetrabenazine (AV-149). The objectives of this study were to evaluate the brain uptake of AV-149 by UPLC-MS/MS and its effect on the biodistribution of [(18)F]AV-133 in the brains of mice. The mice were injected with a bolus including [(18)F]AV-133 and different doses of AV-149. Brain tissue and blood samples were harvested. The effect of different amounts of AV-149 on [(18)F]AV-133 was evaluated by quantifying the brain distribution of radiolabelled tracer [(18)F]AV-133. The concentrations of AV-149 in the brain and plasma were analyzed using a UPLC-MS/MS method. The concentrations of AV-149 in the brain and plasma exhibited a good linear relationship with the doses. The receptor occupancy curve was fit, and the calculated ED50 value was 8.165mg/kg. The brain biodistribution and regional selectivity of [(18)F]AV-133 had no obvious differences at AV-149 doses lower than 0.1mg/kg. With increasing doses of AV-149, the brain biodistribution of [(18)F]AV-133 changed significantly. The results are important to further support that the improved radiolabelling procedure of [(18)F]AV-133 using an SPE method may be suitable for routine clinical application. Copyright © 2015 Elsevier Inc. All rights reserved.

High-dose nifuratel for simple and mixed aerobic vaginitis: A single-center prospective open-label cohort study.

PubMed

Liang, Qian; Li, Nan; Song, Shurong; Zhang, Aihua; Li, Ni; Duan, Ying

2016-10-01

The efficacy and safety of two nifuratel dosages for the treatment of aerobic vaginitis (AV) were compared. This was a prospective open-label cohort study of patients diagnosed and treated at the Tianjin Third Central Hospital between January 2012 and December 2013. The co-presence of bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), or/and trichomonal vaginitis (TV; mixed AV) was determined. Patients were randomized to nifuratel-500 (500 mg nifuratel, intravaginal, 10 days) or nifuratel-250 (250 mg nifuratel, intravaginal, 10 days), and followed-up for three to seven days after treatment completion. Primary and secondary outcomes were recovery rate and adverse events, respectively. The study included 142 patients with AV. Age was not significantly different between the groups (n = 71 each), and disease distribution was identical: 29 (40.85%) simple AV and 42 (59.15%) mixed AV (AV + BV, 42.86 %; AV + VVC, 30.95%; AV + TV, 26.19%). In patients with simple AV, the recovery rate did not differ significantly between the nifuratel-500 (26/29, 89.66%) and nifuratel-250 (22/29, 75.86%) groups. In patients with mixed AV, recovery rates were significantly higher in the nifuratel-500 than in the nifuratel-250 group (AV + BV, 88.89% vs 50.00 %; AV + VVC, 76.92 % vs 30.77 %; AV + TV, 90.91 % vs 36.36%; all P < 0.05). Only one patient (nifuratel-500) reported an adverse event (mild anaphylactic reaction). Nifuratel 500 mg showed good clinical efficacy for the treatment of AV, particularly mixed AV, and is superior to the 250 mg dosage in the treatment of mixed AV. © 2016 Japan Society of Obstetrics and Gynecology.

Reversing the established order: Should adrenal venous sampling precede cross-sectional imaging in the evaluation of primary aldosteronism?

PubMed

Asmar, Melissa; Wachtel, Heather; Yan, Yan; Fraker, Douglas L; Cohen, Debbie; Trerotola, Scott O

2015-08-01

Adrenal venous sampling (AVS) is the definitive evaluation for primary aldosteronism (PA). Pre-AVS cross-sectional imaging does not reduce the need for AVS. The goal of this study was to examine whether performing AVS prior to imaging could decrease the use of imaging in the evaluation of PA at a high volume, experienced center. We performed a retrospective analysis of all AVS procedures (n = 337) done for PA from 2001-2013. Patients whose cross-sectional imaging reports were unavailable (n = 90) or AVS was non-diagnostic (n = 12) were excluded. AVS was performed using modified Mayo technique. Univariate analysis utilized the χ² test and fisher's exact test. Of the 235 patients analyzed, 63% (n = 148) were male. The mean age was 55 ± 11 years. AVS was non-lateralizing in 43% (n = 101); these patients might have avoided imaging with an AVS-first approach. Imaging and AVS were concordant in 52% (n = 123). In patients ≤40yo (n = 23), 35% (n = 8) had no lateralization on AVS, and might have avoided imaging in an AVS-first approach. Imaging and AVS were concordant in 52% (n = 12) of patients ≤ 40yo, versus 52% (n = 111) of patients > 40 yo (P = 0.987). An AVS-first, imaging-second approach could have avoided CT/MRI in 43% of patients. At a high volume, experienced center, performing AVS first on patients with PA may reduce unnecessary cross-sectional imaging studies. © 2015 Wiley Periodicals, Inc.

Towards an atrio-ventricular delay optimization assessed by a computer model for cardiac resynchronization therapy

NASA Astrophysics Data System (ADS)

Ojeda, David; Le Rolle, Virginie; Tse Ve Koon, Kevin; Thebault, Christophe; Donal, Erwan; Hernández, Alfredo I.

2013-11-01

In this paper, lumped-parameter models of the cardiovascular system, the cardiac electrical conduction system and a pacemaker are coupled to generate mitral ow pro les for di erent atrio-ventricular delay (AVD) con gurations, in the context of cardiac resynchronization therapy (CRT). First, we perform a local sensitivity analysis of left ventricular and left atrial parameters on mitral ow characteristics, namely E and A wave amplitude, mitral ow duration, and mitral ow time integral. Additionally, a global sensitivity analysis over all model parameters is presented to screen for the most relevant parameters that a ect the same mitral ow characteristics. Results provide insight on the in uence of left ventricle and atrium in uence on mitral ow pro les. This information will be useful for future parameter estimation of the model that could reproduce the mitral ow pro les and cardiovascular hemodynamics of patients undergoing AVD optimization during CRT.

Implantable cardiac arrhythmia devices--part I: pacemakers.

PubMed

Kusumoto, Fred M; Goldschlager, Nora

2006-05-01

Implantable cardiac devices have become firmly entrenched as important therapeutic tools for a variety of cardiac conditions. The first part of this two-part review will discuss the contemporary use and follow-up of pacemakers, while the second part will address the use of implantable cardioverter defibrillators and implantable loop recorders. Pacemakers are the only available treatment for symptomatic bradycardia not due to reversible causes. Large randomized studies have demonstrated a small but statistically significant reduction in atrial fibrillation associated with pacing modes that maintain atrioventricular synchrony. In contrast, pacing mode appears to have a less dramatic effect in patients with atrioventricular block. Cardiac resynchronization with specialized left ventricular leads has been shown to reduce symptoms and improve survival in patients with symptomatic heart failure, systolic dysfunction, and widened QRS complexes. For all patients, careful follow-up is necessary to ensure optimal therapeutic benefit of pacing systems.

Patients' and procedural characteristics of AV-block during slow pathway modulation for AVNRT-single center 10year experience.

PubMed

Wasmer, Kristina; Dechering, Dirk G; Köbe, Julia; Leitz, Patrick; Frommeyer, Gerrit; Lange, Phillip S; Kochhäuser, Simon; Reinke, Florian; Pott, Christian; Mönnig, Gerold; Breithardt, Günter; Eckardt, Lars

2017-10-01

Permanent AV-block is a recognized and feared complication of slow pathway modulation for AVNRT. We aimed to assess incidence of transient and permanent AV-block as well as consequences of transient AV-block in a large contemporary AVNRT ablation cohort. We searched our single center prospective ablation database for occurrence of transient and permanent AV-block during slow pathway modulation between January 2004 and October 2015. We analyzed patients' and procedural characteristics as well as outcome of patients in whom transient or permanent AV-block occurred. Of 9170 patients who underwent a catheter ablation at our institution between January 2004 and October 2015, 2101 patients (64% women, mean age 50±18years) underwent slow pathway modulation. In three patients, permanent AV-block occurred during RF application. Additional two patients had transient AV-block that recovered (after a few minutes and 25min), but recurred within two days of the procedure. All five patients underwent dual chamber pacemaker implantation (0.2%). Transient AV-block related to RF delivery occurred in 44 patients (2%). Transient mechanical AV-block occurred in additional 17 patients (0.8%). In 12 patients, ablation was continued despite transient AV-block. One of these patients developed permanent AV-block. Permanent AV-block following slow pathway modulation is a rare event, occurring in 0.2% of patients in a large contemporary single center cohort. Transient AV-block is more frequent (2%). Copyright © 2017 Elsevier B.V. All rights reserved.

After-visit summaries in primary care: mixed methods results from a literature review and stakeholder interviews.

PubMed

Lyles, Courtney R; Gupta, Reena; Tieu, Lina; Fernandez, Alicia

2018-05-28

After-visit summary (AVS) documents presenting key information from each medical encounter have become standard in the USA due to federal health care reform. Little is known about how they are used or whether they improve patient care. First, we completed a literature review and described the totality of the literature on AVS by article type and major outcome measures. Next, we used reputational sampling from large-scale US studies on primary care to identify and interview nine stakeholders on their perceptions of AVS across high-performing primary care practices. Interviews were transcribed and coded for AVS use in practice, perceptions of the best/worst features and recommendations for improving AVS utility in routine care. The literature review resulted in 17 studies; patients reported higher perceived value of AVS compared with providers, despite poor recall of specific AVS content and varied post-visit use. In key informant interviews, key informants expressed enthusiasm for the potential of using AVS to reinforce key information with patients, especially if AVS were customizable. Despite this potential, key informants found that AVS included incorrect information and did not feel that patients or their practices were using AVS to enhance care. There is a gap between the potential of AVS and how providers and patients are using it in routine care. Suggestions for improved use of AVS include increasing customization, establishing care team responsibilities and workflows and ensuring patients with communication barriers have dedicated support to review AVS during visits.

Investigation of mechanisms and non-pharmacological therapy of cardiac arrhythmias

NASA Astrophysics Data System (ADS)

Vago, Hajnalka

Learning of mechanisms of arrhythmias may contribute substantially to the development of effective pharmacological and non-pharmacological therapeutic methods. Clinical relevance of endothelin-1 (ET-1), a strong vasoconstrictor and arrhythmogenic endogenous substrate, is not clarified yet. In our experimental studies, performed in the in situ canine heart, electrophysiological effects and the role in the pathomechanism of malignant ventricular tachyarrhythmias of endogenous and exogenous ET-1 was investigated. It has been proven in the in vivo ischaemia-reperfusion canine heart model, that during reperfusion ET-1 and big-ET levels increase in the coronary sinus, however there was no correlation between endothelin levels and electrophysiological changes. ET A-receptor antagonist darusentan does not prevent electrophysiological changes and development of ventricular tachyarrhythmias during ischaemia and reperfusion. On the contrary, during ischaemia endogenous ET-1 tends to show balancing effect. It has been proven that administration of high dose intracoronary ET-1 bolus has dual, ischaemic and direct, electrophysiological effect. It has been shown for the first time, that ET-1 causes monophasic action potential (MAP) and T-wave alternant. Our clinical study leads to the conclusion that previous atrial fibrillation, absence of preoperative beta-blocker treatment and combined heart surgery are strong predictors of atrial fibrillation following open heart surgery. The basis of new nonpharmacological therapies is the learning of pathomechanisms of arrhythmias and in some cases heart failure, which is an arrhythmogenic substrate. In our experimental study reliable MAP measurements, suitable for investigation of arrhythmogenesis, were performed for the first time using fractally coated ablation catheters during spontaneous rate and during stimulations. It has been proven that radiofrequency ablation affects significantly MAP parameters. In Hungary, we were the first to apply effectively biatrial pacemaker and biatrial cardioverter defibrillator for the prevention of paroxysmal atrial fibrillation. In the majority of patients frequency of paroxysmal atrial fibrillation decreased significantly due to biatrial stimulation or combined pharmacological and resynchronisation therapy. Parasymphathetic cardiac neurostimulation is a promising new non-pharmacological treatment option in certain types of arrhythmias. In our clinical study we were able to stimulate cardiac parasympathetic nerves innervating atrioventricular node achieving ventricular rate control during atrial tachyarrhythmias with chronically implanted coronary sinus lead. In our study biventricular pacemakers and cardioverter defibrillators were applied successfully in the treatment of drug refractory congestive heart failure combined with inter- and/or intraventricular conduction disturbances. AV sequential left sided chronic pacing using a single lead located in the coronary sinus has not been previously reported. Left sided DDD pacing was effective chronically in the improvement of the functional stage of patient suffering from congestive heart disease combined with left bundle branch block and binodal disease. Parallel with the investigation of pathomechanism of life-threatening ventricular tachyarrhythmias and the most common, clinically relevant atrial fibrillation due to recent technical development, we were able to support nonpharmacological therapeutic modalities, gaining popularity in clinical management, with novel observations.

Cyclic Mechanical Loading Is Essential for Rac1-Mediated Elongation and Remodeling of the Embryonic Mitral Valve.

PubMed

Gould, Russell A; Yalcin, Huseyin C; MacKay, Joanna L; Sauls, Kimberly; Norris, Russell; Kumar, Sanjay; Butcher, Jonathan T

2016-01-11

During valvulogenesis, globular endocardial cushions elongate and remodel into highly organized thin fibrous leaflets. Proper regulation of this dynamic process is essential to maintain unidirectional blood flow as the embryonic heart matures. In this study, we tested how mechanosensitive small GTPases, RhoA and Rac1, coordinate atrioventricular valve (AV) differentiation and morphogenesis. RhoA activity and its regulated GTPase-activating protein FilGAP are elevated during early cushion formation but decreased considerably during valve remodeling. In contrast, Rac1 activity was nearly absent in the early cushions but increased substantially as the valve matured. Using gain- and loss-of-function assays, we determined that the RhoA pathway was essential for the contractile myofibroblastic phenotype present in early cushion formation but was surprisingly insufficient to drive matrix compaction during valve maturation. The Rac1 pathway was necessary to induce matrix compaction in vitro through increased cell adhesion, elongation, and stress fiber alignment. Facilitating this process, we found that acute cyclic stretch was a potent activator of RhoA and subsequently downregulated Rac1 activity via FilGAP. On the other hand, chronic cyclic stretch reduced active RhoA and downstream FilGAP, which enabled Rac1 activation. Finally, we used partial atrial ligation experiments to confirm in vivo that altered cyclic mechanical loading augmented or restricted cushion elongation and thinning, directly through potentiation of active Rac1 and active RhoA, respectively. Together, these results demonstrate that cyclic mechanical signaling coordinates the RhoA to Rac1 signaling transition essential for proper embryonic mitral valve remodeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2012-09-01

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

Impact of high-grade Atrioventricular block and cumulative frequent pacing on atrial arrhythmias.

PubMed

Wali, Eisha; Deshmukh, Amrish; Bukari, Abdallah; Broman, Michael; Aziz, Zaid; Beaser, Andrew; Upadhyay, Gaurav; Nayak, Hemal M; Tung, Roderick; Ozcan, Cevher

2018-06-21

The relationship between high-grade AV block (HGAVB) with cumulative frequent pacing and risk of atrial arrhythmias (AAs) has not been well characterized. We hypothesized HGAVB and pacing may have significant impact on incidence and prevalence of AAs by modulating atrial substrate. To determine impact of HGAVB and pacing on AAs including atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT). All consecutive patients who underwent dual chamber pacemaker implantation for HGAVB from 2005 to 2011 at the University of Chicago were included. AAs and percent of pacing were detected through device interrogation. Patients' data were collected from electronic medical records and clinic visits. A total of 166 patients (mean age 71±15 years; 54% female, 56% African-American) were studied. AF was documented in 27% of patients before pacemaker implantation. During a mean 5.8±2.2 years of follow-up, 47% had device-detected AF, 10% AFL and 26% AT. New-onset AF was documented in 40 of the 122 patients without prior AF (33%). Continuous (≥99%) right ventricular pacing was associated with significantly decreased AF prevalence (34% versus 59%, p = 0.005), and correlated with lower incidence (26% versus 41%, p = 0.22). Pacing suppressed AF in 14% of patients with baseline AF; those patients had lower atrial pacing (3.2% versus 45%, p < 0.0001). Left atrial dilation was the only independent predictor of AF with frequent pacing (p = 0.009). HGAVB is associated with high incidence and prevalence of AAs with and without pacing. Cumulative frequent (≥99%) ventricular pacing reduces risk of AF in patients with HGAVB. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

A survey of cardiac implantable electronic device implantation in India: By Indian Society of Electrocardiology and Indian Heart Rhythm Society.

PubMed

Shenthar, Jayaprakash; Bohra, Shomu; Jetley, Vinay; Vora, Amit; Lokhandwala, Yash; Nabar, Ashish; Naik, Ajay; Calambur, Narsimhan; Gupta, S B

2016-01-01

There is limited data regarding the demographics and type of cardiac implantable electronic device (CIED) in India. The aim of this survey was to define trends in CIED implants, which included permanent pacemakers (PM), intracardiac defibrillators (ICD), and cardiac resynchronization therapy pacemakers and defibrillators (CRT-P/D) devices in India. The survey was the initiative of the Indian Society of Electrocardiology and the Indian Heart Rhythm Society. The type of CIED used, their indications, demographic characteristics, clinical status and co-morbidities were collected using a survey form over a period of 1 year. 2117 forms were analysed from 136 centers. PM for bradyarrhythmic indication constituted 80% of the devices implanted with ICD's and CRT-P/D forming approximately 10% each. The most common indication for PM implantation was complete atrio-ventricular block (76%). Single chamber (VVI) pacemakers formed 54% of implants, majority in males (64%). The indication for ICD implantation was almost equal for primary and secondary prevention. A single chamber ICD was most commonly implanted (65%). Coronary artery disease was the etiology in 58.5% of patients with ICD implants. CRT pacemakers were implanted mostly in patients with NYHA III/IV (82%), left ventricular ejection fraction <0.35 (88%) with CRT-P being most commonly used (57%). A large proportion of CIED implants in India are PM for bradyarrhythmic indications, predominantly AV block. ICD's are implanted almost equally for primary and secondary prophylaxis. Most CRT devices are implanted for NYHA Class III. There is a male predominance for implantation of CIED. Copyright © 2015 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Investigation of an N-Terminal Prohormone of Brain Natriuretic Peptide Point-of-Care ELISA in Clinically Normal Cats and Cats With Cardiac Disease.

PubMed

Harris, A N; Beatty, S S; Estrada, A H; Winter, B; Bohannon, M; Sosa, I; Hanscom, J; Mainville, C A; Gallagher, A E

2017-07-01

N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentrations may be increased in cats with various cardiac disorders. The point-of-care (POC) ELISA assay uses the same biologic reagents as the quantitative NT-proBNP ELISA. Previous studies have evaluated the sensitivity and specificity of the POC ELISA in cats with cardiac disease. To prospectively evaluate the diagnostic utility of the POC ELISA in a select population of cats. Thirty-eight client-owned cats presented to the University of Florida Cardiology Service for cardiac evaluation. Fifteen apparently healthy cats recruited as part of another study. Physical examination and echocardiography were performed in all cats. The POC ELISA was assessed visually as either positive or negative by a reader blinded to the echocardiographic findings, and results were analyzed relative to quantitative assay results. Twenty-six cats were diagnosed with underlying cardiac disease, and 27 cats were considered free of cardiac disease. Cats with cardiac disease included: 21 with hypertrophic cardiomyopathy, 2 with unclassified cardiomyopathy, 2 with restrictive cardiomyopathy, and 1 with 3rd degree atrioventricular (AV) block. The POC ELISA differentiated cats with cardiac disease with a sensitivity of 65.4% and specificity of 100%. The POC NT-proBNP ELISA performed moderately well in a selected population of cats. A negative test result cannot exclude the presence of underlying cardiac disease, and a positive test result indicates that cardiac disease likely is present, but further diagnostic investigation would be indicated for a definitive diagnosis. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Is there a role for segmental adrenal venous sampling and adrenal sparing surgery in patients with primary aldosteronism?

PubMed

Satoh, Fumitoshi; Morimoto, Ryo; Seiji, Kazumasa; Satani, Nozomi; Ota, Hideki; Iwakura, Yoshitsugu; Ono, Yoshikiyo; Kudo, Masataka; Nezu, Masahiro; Omata, Kei; Tezuka, Yuta; Kawasaki, Yoshihide; Ishidoya, Shigeto; Arai, Yoichi; Takase, Kei; Nakamura, Yasuhiro; McNamara, Keely; Sasano, Hironobu; Ito, Sadayoshi

2015-10-01

Adrenal venous sampling (AVS) is critical to determine the subtype of primary aldosteronism (PA). Central AVS (C-AVS)--that is, the collection of effluents from bilateral adrenal central veins (CV)--sometimes does not allow differentiation between bilateral aldosterone-producing adenomas (APA) and idiopathic hyperaldosteronism. To establish the best treatment course, we have developed segmental AVS (S-AVS); that is, we collect effluents from the tributaries of CV to determine the intra-adrenal sources of aldosterone overproduction. We then evaluated the clinical utility of this novel approach in the diagnosis and treatment of PA. We performed C-AVS and/or S-AVS in 297 PA patients and assessed the accuracy of diagnosis based on the results of C-AVS (n=138, 46.5%) and S-AVS (n=159, 53.5%) by comparison with those of clinicopathological evaluation of resected specimens. S-AVS demonstrated both elevated and attenuated secretion of aldosterone from APA and non-tumorous segments, respectively, in patients with bilateral APA and recurrent APA. These findings were completely confirmed by detailed histopathological examination after surgery. S-AVS, but not C-AVS, also served to identify APA located distal from the CV. Compared to C-AVS, S-AVS served to identify APA in some patients, and its use should expand the pool of patients eligible for adrenal sparing surgery through the identification of unaffected segments, despite the fact that S-AVS requires more expertise and time. Especially, this new technique could enormously benefit patients with bilateral or recurrent APA because of the preservation of non-tumorous glandular tissue. © 2015 European Society of Endocrinology.

Development of the Hearts of Lizards and Snakes and Perspectives to Cardiac Evolution

PubMed Central

Jensen, Bjarke; van den Berg, Gert; van den Doel, Rick; Oostra, Roelof-Jan; Wang, Tobias; Moorman, Antoon F. M.

2013-01-01

Birds and mammals both developed high performance hearts from a heart that must have been reptile-like and the hearts of extant reptiles have an unmatched variability in design. Yet, studies on cardiac development in reptiles are largely old and further studies are much needed as reptiles are starting to become used in molecular studies. We studied the growth of cardiac compartments and changes in morphology principally in the model organism corn snake (Pantherophis guttatus), but also in the genotyped anole (Anolis carolinenis and A. sagrei) and the Philippine sailfin lizard (Hydrosaurus pustulatus). Structures and chambers of the formed heart were traced back in development and annotated in interactive 3D pdfs. In the corn snake, we found that the ventricle and atria grow exponentially, whereas the myocardial volumes of the atrioventricular canal and the muscular outflow tract are stable. Ventricular development occurs, as in other amniotes, by an early growth at the outer curvature and later, and in parallel, by incorporation of the muscular outflow tract. With the exception of the late completion of the atrial septum, the adult design of the squamate heart is essentially reached halfway through development. This design strongly resembles the developing hearts of human, mouse and chicken around the time of initial ventricular septation. Subsequent to this stage, and in contrast to the squamates, hearts of endothermic vertebrates completely septate their ventricles, develop an insulating atrioventricular plane, shift and expand their atrioventricular canal toward the right and incorporate the systemic and pulmonary venous myocardium into the atria. PMID:23755108

The effect of different atrioventricular delays on left atrium and left atrial appendage function in patients with DDD pacemaker.

PubMed

Kanadaşı, Mehmet; Caylı, Murat; Sahin, Durmuş Yıldıray; Sen, Ömer; Koç, Mevlüt; Usal, Ayhan; Batur, Mustafa Kemal; Demirtaş, Mustafa

2011-07-01

Although it has been known that optimization of atrioventricular delay (AVD) has favorable effect on the left ventricular functions in patients with DDD pacemaker, the effect of different AVDs on left atrium (LA) and left atrial appendage (LAA) functions has not been exactly evaluated. The aim of the present study was to assess the effect of different AVDs on LA and LAA functions in DDD pacemaker implanted patients with atrioventricular block. Forty-eight patients with DDD pacemaker were enrolled into the study. Patients were divided into two groups according to the echocardiographic diastolic function: Group I (normal diastolic function) and Group II (diastolic dysfunction). LAA emptying velocity on pulsed wave Doppler and LAA late systolic wave velocity by using tissue Doppler were recorded. Patients were paced for five successive continuous pacing periods of 10 minutes duration using five selective AVDs (80-250 ms). Significant effect on LA and LAA functions has not been observed by the setting of AVD in Group I. However, when the AVD was gradually shortened form 150 ms to 80 ms, LA and LAA functions gradually decreased in Group II patients. When AVD increased to 200 ms, LA and LAA functions were improved. Further increase in AVD resulted in decreased LA and LAA functions. Setting of AVD has not significant effect on the LA and LAA functions in patients with normal diastolic function, but moderate prolongation of AVD in physiological limits improved LA and LAA functions in DDD pacemaker implanted patients with diastolic dysfunction. © 2011, Wiley Periodicals, Inc.

Role of adrenal vein sampling in primary aldosteronism: the Monash Health experience.

PubMed

Teng, J; Hutchinson, M E; Doery, J C G; Choy, K W; Chong, W; Fuller, P J; Yang, J

2015-11-01

Adrenal vein sampling (AVS) is useful for distinguishing unilateral versus bilateral hypersecretion in primary aldosteronism (PA), but is technically challenging. Furthermore, the use of adrenocorticotropic hormone (ACTH)-stimulation in AVS is controversial. We implemented a Monash Health-specific AVS protocol in 2010. The audit aimed to: (i) examine the impact of a dedicated protocol on success rates of AVS at a tertiary referral centre; (ii) evaluate the impact of AVS on sub-typing of PA; and (iii) assess the utility of ACTH stimulation in AVS. AVS was performed on patients with PA confirmed by positive saline suppression testing (aldosterone level >140 pmol/L post-saline infusion), with sequential sampling of adrenal and peripheral veins, pre- and post-ACTH infusion. Patients with unilateral aldosterone-producing adenoma diagnosed on successful AVS were referred for adrenalectomy. Between 2010 and 2014 inclusive, a total of 28 AVS procedures was performed, with complete pre- and post-ACTH data for 19 procedures. Bilateral successful cannulation rates improved post-implementation of our protocol (61% vs 41%). Of the patients, 32% had discordant imaging and AVS results: four patients with unilateral adenomas did not lateralise on AVS and were managed medically; four patients with bilateral or no adenomas on imaging, lateralised on AVS and had surgery. Overall, use of ACTH did not increase successful cannulation and tended to mask lateralisation. AVS is crucial in subtype classification of PA and should be performed by a dedicated radiologist with a standardised protocol. AVS outcomes were not improved with the use of ACTH stimulation. © 2015 Royal Australasian College of Physicians.

Structure-function analysis of Avian β-defensin-6 and β-defensin-12: role of charge and disulfide bridges.

PubMed

Yang, Ming; Zhang, Chunye; Zhang, Xuehan; Zhang, Michael Z; Rottinghaus, George E; Zhang, Shuping

2016-09-09

Avian beta-defensins (AvBD) are small, cationic, antimicrobial peptides. The potential application of AvBDs as alternatives to antibiotics has been the subject of interest. However, the mechanisms of action remain to be fully understood. The present study characterized the structure-function relationship of AvBD-6 and AvBD-12, two peptides with different net positive charges, similar hydrophobicity and distinct tissue expression profiles. AvBD-6 was more potent than AvBD-12 against E. coli, S. Typhimurium, and S. aureus as well as clinical isolates of extended spectrum beta lactamase (ESBL)-positive E. coli and K. pneumoniae. AvBD-6 was more effective than AvBD-12 in neutralizing LPS and interacting with bacterial genomic DNA. Increasing bacterial concentration from 10(5) CFU/ml to 10(9) CFU/ml abolished AvBDs' antimicrobial activity. Increasing NaCl concentration significantly inhibited AvBDs' antimicrobial activity, but not the LPS-neutralizing function. Both AvBDs were mildly chemotactic for chicken macrophages and strongly chemotactic for CHO-K1 cells expressing chicken chemokine receptor 2 (CCR2). AvBD-12 at higher concentrations also induced chemotactic migration of murine immature dendritic cells (DCs). Disruption of disulfide bridges abolished AvBDs' chemotactic activity. Neither AvBDs was toxic to CHO-K1, macrophages, or DCs. AvBDs are potent antimicrobial peptides under low-salt conditions, effective LPS-neutralizing agents, and broad-spectrum chemoattractant peptides. Their antimicrobial activity is positively correlated with the peptides' net positive charges, inversely correlated with NaCl concentration and bacterial concentration, and minimally dependent on intramolecular disulfide bridges. In contrast, their chemotactic property requires the presence of intramolecular disulfide bridges. Data from the present study provide a theoretical basis for the design of AvBD-based therapeutic and immunomodulatory agents.

Attachment styles in patients with avoidant personality disorder compared with social phobia.

PubMed

Eikenaes, Ingeborg; Pedersen, Geir; Wilberg, Theresa

2016-09-01

Avoidant personality disorder (AvPD) and social phobia (SP) are common, closely related conditions. Little is known about the underlying processes related to the social discomfort of subjects with AvPD and SP. Both disorders are associated with interpersonal problems. An attachment perspective may shed light on similarities and differences in close relationships between the disorders. The aim of the study was to compare self-reported attachment styles in patients with AvPD and SP. We expected that patients with AvPD would have more attachment anxiety and avoidance and more often a Fearful attachment style, compared with SP. This is a cross-sectional multisite study of 90 adult patients with AvPD and SP. Patients with AvPD with and without SP (AvPD group) were compared with patients with SP without AvPD (SP group). Patients were assessed using structured diagnostic interviews and self-reporting questionnaires, including Experiences in Close Relationships (ECR). The ECR dimensions, Anxiety and Avoidance, and the new described five factors of the ECR were used. The AvPD group had higher levels of attachment anxiety than the SP group, especially for the sub-factors Anxiety for abandonment and Separation frustration. The diagnostic groups did not differ in levels of avoidance. Anxiety for abandonment was still associated with AvPD after controlling for symptom disorders and the criteria of other personality disorders. A Fearful attachment style was more frequent among patients with AvPD. The results indicate AvPD is associated with more attachment anxiety than SP. Fear of abandonment may play a significant role in the AvPD pathology. This is the first study to compare attachment styles in patients with avoidant personality disorder (AvPD) and social phobia (SP). The AvPD group had higher attachment-related anxiety than the SP group, and anxiety was most pronounced for the fear of abandonment. Fear of abandonment may play an important role in the AvPD pathology. © 2015 The British Psychological Society.

AUDIO-VISUAL INSTRUCTION, AN ADMINISTRATIVE HANDBOOK.

ERIC Educational Resources Information Center

Missouri State Dept. of Education, Jefferson City.

THIS HANDBOOK WAS DESIGNED FOR USE BY SCHOOL ADMINISTRATORS IN DEVELOPING A TOTAL AUDIOVISUAL (AV) PROGRAM. ATTENTION IS GIVEN TO THE IMPORTANCE OF AUDIOVISUAL MEDIA TO EFFECTIVE INSTRUCTION, ADMINISTRATIVE PERSONNEL REQUIREMENTS FOR AN AV PROGRAM, BUDGETING FOR AV INSTRUCTION, PROPER UTILIZATION OF AV MATERIALS, SELECTION OF AV EQUIPMENT AND…

Mild mitral and tricuspid regurgitation secondary to pericardial constriction.

PubMed

Mittal, S R

2014-06-01

A 26 years female presented with pericardial effusion. On follow up she developed pericardial constriction with new appearance of mild mitral and tricuspid regurgitation without any other pathology. Fibrosis along posterior atrioventricular groove could be responsible for regurgitation.

Pharmacokinetics of avenanthramides (AV) from AV-enriched malted oats in healthy older adults

USDA-ARS?s Scientific Manuscript database

Avenanthramides (AV) are a unique group of phytochemicals found in oat bran. In vitro studies show both purified AV and concentrated oat AV mixtures have anti-atherogenic and anti-inflammatory activity, suggesting they may have similar effects in vivo if they are sufficiently bioavailable. The bioav...

AVS on satellite

NASA Astrophysics Data System (ADS)

Zhao, Haiwu; Wang, Guozhong; Hou, Gang

2005-07-01

AVS is a new digital audio-video coding standard established by China. AVS will be used in digital TV broadcasting and next general optical disk. AVS adopted many digital audio-video coding techniques developed by Chinese company and universities in recent years, it has very low complexity compared to H.264, and AVS will charge very low royalty fee through one-step license including all AVS tools. So AVS is a good and competitive candidate for Chinese DTV and next generation optical disk. In addition, Chinese government has published a plan for satellite TV signal directly to home(DTH) and a telecommunication satellite named as SINO 2 will be launched in 2006. AVS will be also one of the best hopeful candidates of audio-video coding standard on satellite signal transmission.

Novel synthetic analogues of avian β-defensin-12: the role of charge, hydrophobicity, and disulfide bridges in biological functions.

PubMed

Yang, Ming; Zhang, Chunye; Zhang, Michael Z; Zhang, Shuping

2017-02-23

Avian β-defensins (AvBD) possess broad-spectrum antimicrobial, LPS neutralizing and chemotactic properties. AvBD-12 is a chemoattractant for avian immune cells and mammalian dendritic cells (JAWSII) - a unique feature that is relevant to the applications of AvBDs as chemotherapeutic agents in mammalian hosts. To identify the structural components essential to various biological functions, we have designed and evaluated seven AvBD analogues. In the first group of analogues, the three conserved disulfide bridges were eliminated by replacing cysteines with alanine and serine residues, peptide hydrophobicity and charge were increased by changing negatively charged amino acid residues to hydrophobic (AvBD-12A1) or positively charged residues (AvBD-12A2 and AvBD-12A3). All three analogues in this group showed improved antimicrobial activity, though AvBD-12A3, with a net positive charge of +9, hydrophobicity of 40% and a predicted CCR2 binding domain, was the most potent antimicrobial peptide. AvBD-12A3 also retained more than 50% of wild type chemotactic activity. In the second group of analogues (AvBD-12A4 to AvBD-12A6), one to three disulfide bridges were removed via substitution of cysteines with isosteric amino acids. Their antimicrobial activity was compromised and chemotactic activity abolished. The third type of analogue was a hybrid that had the backbone of AvBD-12 and positively charged amino acid residues AvBD-6. The antimicrobial and chemotactic activities of the hybrid resembled that of AvBD-6 and AvBD-12, respectively. While the net positive charge and charge distribution have a dominating effect on the antimicrobial potency of AvBDs, the three conserved disulfide bridges are essential to the chemotactic property and the maximum antimicrobial activity. Analogue AvBD-12A3 with a high net positive charge, a moderate degree of hydrophobicity and a CCR2-binding domain can serve as a template for the design of novel antimicrobial peptides with chemotactic property and salt resistance.

Expression of host defense peptides in the intestine of Eimeria-challenged chickens.

PubMed

Su, S; Dwyer, D M; Miska, K B; Fetterer, R H; Jenkins, M C; Wong, E A

2017-07-01

Avian coccidiosis is caused by the intracellular protozoan Eimeria, which produces intestinal lesions leading to weight gain depression. Current control methods include vaccination and anticoccidial drugs. An alternative approach involves modulating the immune system. The objective of this study was to profile the expression of host defense peptides such as avian beta-defensins (AvBDs) and liver expressed antimicrobial peptide 2 (LEAP2), which are part of the innate immune system. The mRNA expression of AvBD family members 1, 6, 8, 10, 11, 12, and 13 and LEAP2 was examined in chickens challenged with either E. acervulina, E. maxima, or E. tenella. The duodenum, jejunum, ileum, and ceca were collected 7 d post challenge. In study 1, E. acervulina challenge resulted in down-regulation of AvBD1, AvBD6, AvBD10, AvBD11, AvBD12, and AvBD13 in the duodenum. E. maxima challenge caused down-regulation of AvBD6, AvBD10, and AvBD11 in the duodenum, down-regulation of AvBD10 in the jejunum, but up-regulation of AvBD8 and AvBD13 in the ceca. E. tenella challenge showed no change in AvBD expression in any tissue. In study 2, which involved challenge with only E. maxima, there was down-regulation of AvBD1 in the ileum, AvBD11 in the jejunum and ileum, and LEAP2 in all 3 segments of the small intestine. The expression of LEAP2 was further examined by in situ hybridization in the jejunum of chickens from study 2. LEAP2 mRNA was expressed similarly in the enterocytes lining the villi, but not in the crypts of control and Eimeria challenged chickens. The lengths of the villi in the Eimeria challenged chickens were less than those in the control chickens, which may in part account for the observed down-regulation of LEAP2 mRNA quantified by PCR. Overall, the AvBD response to Eimeria challenge was not consistent; whereas LEAP2 was consistently down-regulated, which suggests that LEAP2 plays an important role in modulating an Eimeria infection. Published by Oxford University Press on behalf of Poultry Science Association 2017.

Real-Time PCR with an Internal Control for Detection of All Known Human Adenovirus Serotypes▿

PubMed Central

Damen, Marjolein; Minnaar, René; Glasius, Patricia; van der Ham, Alwin; Koen, Gerrit; Wertheim, Pauline; Beld, Marcel

2008-01-01

The “gold standard” for the diagnosis of adenovirus (AV) infection is virus culture, which is rather time-consuming. Especially for immunocompromised patients, in whom severe infections with AV have been described, rapid diagnosis is important. Therefore, an internally controlled AV real-time PCR assay detecting all known human AV serotypes was developed. Primers were chosen from the hexon region, which is the most conserved region, and in order to cover all known serotypes, degenerate primers were used. The internal control (IC) DNA contained the same primer binding sites as the AV DNA control but had a shuffled probe region compared to the conserved 24-nucleotide consensus AV hexon probe region (the target). The IC DNA was added to the clinical sample in order to monitor extraction and PCR efficiency. The sensitivity and the linearity of the AV PCR were determined. For testing the specificity of this PCR assay for human AVs, a selection of 51 AV prototype strains and 66 patient samples positive for other DNA viruses were tested. Moreover, a comparison of the AV PCR method described herein with culture and antigen (Ag) detection was performed with a selection of 151 clinical samples. All 51 AV serotypes were detected in the selection of AV prototype strains. Concordant results from culture or Ag detection and PCR were found for 139 (92.1%) of 151 samples. In 12 cases (7.9%), PCR was positive while the culture was negative. In conclusion, a sensitive, internally controlled nonnested AV real-time PCR assay which is able to detect all known AV serotypes with higher sensitivity than a culture or Ag detection method was developed. PMID:18923006

Predictors of nonfunctional arteriovenous access at hemodialysis initiation and timing of access creation: A registry-based study

PubMed Central

Metzger, Marie; Labeeuw, Michel; Ayav, Carole; Jacquelinet, Christian; Massy, Ziad A.; Stengel, Bénédicte

2017-01-01

Determinants of nonfunctional arteriovenous (AV) access, including timing of AV access creation, have not been sufficiently described. We studied 29 945 patients who had predialysis AV access placement and were included in the French REIN registry from 2005 through 2013. AV access was considered nonfunctional when dialysis began with a catheter. We estimated crude and adjusted odds ratio (OR) with 95% confidence intervals (CI) of nonfunctional versus functional AV access associated with case-mix, facility characteristics, and timing of AV access creation. Analyses were stratified by dialysis start condition (planned or as an emergency) and comorbidity profile. Overall, 18% patients had nonfunctional AV access at hemodialysis initiation. In the group with planned dialysis start, female gender (OR 1.43, 95% CI 1.32–1.56), diabetes (OR 1.28, 95% CI 1.15–1.44), and a higher number of cardiovascular comorbidities (OR 1.27, 95% CI 1.09–1.49, and 1.31, 1.05–1.64, for 3 and >3 cardiovascular comorbidities versus none, respectively) were independent predictors of nonfunctional AV access. A higher percentage of AV access creation at the region level was associated with a lower rate of nonfunctional AV access (OR 0.98, 95% CI 0.98–0.99 per 1% increase). The odds of nonfunctional AV access decreased as time from creation to hemodialysis initiation increased up to 3 months in nondiabetic patients with fewer than 2 cardiovascular comorbidities and 6 months in patients with diabetes or 2 or more such comorbidities. In conclusion, both patient characteristics and clinical practices may play a role in successful AV access use at hemodialysis initiation. Adjusting the timing of AV access creation to patients’ comorbidity profiles may improve functional AV access rates. PMID:28749967

Predictors of nonfunctional arteriovenous access at hemodialysis initiation and timing of access creation: A registry-based study.

PubMed

Alencar de Pinho, Natalia; Coscas, Raphael; Metzger, Marie; Labeeuw, Michel; Ayav, Carole; Jacquelinet, Christian; Massy, Ziad A; Stengel, Bénédicte

2017-01-01

Determinants of nonfunctional arteriovenous (AV) access, including timing of AV access creation, have not been sufficiently described. We studied 29 945 patients who had predialysis AV access placement and were included in the French REIN registry from 2005 through 2013. AV access was considered nonfunctional when dialysis began with a catheter. We estimated crude and adjusted odds ratio (OR) with 95% confidence intervals (CI) of nonfunctional versus functional AV access associated with case-mix, facility characteristics, and timing of AV access creation. Analyses were stratified by dialysis start condition (planned or as an emergency) and comorbidity profile. Overall, 18% patients had nonfunctional AV access at hemodialysis initiation. In the group with planned dialysis start, female gender (OR 1.43, 95% CI 1.32-1.56), diabetes (OR 1.28, 95% CI 1.15-1.44), and a higher number of cardiovascular comorbidities (OR 1.27, 95% CI 1.09-1.49, and 1.31, 1.05-1.64, for 3 and >3 cardiovascular comorbidities versus none, respectively) were independent predictors of nonfunctional AV access. A higher percentage of AV access creation at the region level was associated with a lower rate of nonfunctional AV access (OR 0.98, 95% CI 0.98-0.99 per 1% increase). The odds of nonfunctional AV access decreased as time from creation to hemodialysis initiation increased up to 3 months in nondiabetic patients with fewer than 2 cardiovascular comorbidities and 6 months in patients with diabetes or 2 or more such comorbidities. In conclusion, both patient characteristics and clinical practices may play a role in successful AV access use at hemodialysis initiation. Adjusting the timing of AV access creation to patients' comorbidity profiles may improve functional AV access rates.

Failure mode analysis in adrenal vein sampling: a single-center experience.

PubMed

Trerotola, Scott O; Asmar, Melissa; Yan, Yan; Fraker, Douglas L; Cohen, Debbie L

2014-10-01

To analyze failure modes in a high-volume adrenal vein sampling (AVS) practice in an effort to identify preventable causes of nondiagnostic sampling. A retrospective database was constructed containing 343 AVS procedures performed over a 10-year period. Each nondiagnostic AVS procedure was reviewed for failure mode and correlated with results of any repeat AVS. Data collected included selectivity index, lateralization index, adrenalectomy outcomes if performed, and details of AVS procedure. All AVS procedures were performed after cosyntropin stimulation, using sequential technique. AVS was nondiagnostic in 12 of 343 (3.5%) primary procedures and 2 secondary procedures. Failure was right-sided in 8 (57%) procedures, left-sided in 4 (29%) procedures, bilateral in 1 procedure, and neither in 1 procedure (laboratory error). Failure modes included diluted sample from correctly identified vein (n = 7 [50%]; 3 right and 4 left), vessel misidentified as adrenal vein (n = 3 [21%]; all right), failure to locate an adrenal vein (n = 2 [14%]; both right), cosyntropin stimulation failure (n = 1 [7%]; diagnostic by nonstimulated criteria), and laboratory error (n = 1 [7%]; specimen loss). A second AVS procedure was diagnostic in three of five cases (60%), and a third AVS procedure was diagnostic in one of one case (100%). Among the eight patients in whom AVS ultimately was not diagnostic, four underwent adrenalectomy based on diluted AVS samples, and one underwent adrenalectomy based on imaging; all five experienced improvement in aldosteronism. A substantial percentage of AVS failures occur on the left, all related to dilution. Even when technically nondiagnostic per strict criteria, some "failed" AVS procedures may be sufficient to guide therapy. Repeat AVS has a good yield. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

Diagnostic and therapeutic advancements for aerobic vaginitis.

PubMed

Han, Cha; Wu, Wenjuan; Fan, Aiping; Wang, Yingmei; Zhang, Huiying; Chu, Zanjun; Wang, Chen; Xue, Fengxia

2015-02-01

Aerobic vaginitis (AV) is a newly defined clinical entity that is distinct from candidiasis, trichomoniasis and bacterial vaginosis (BV). Because of the poor recognition of AV, this condition can lead to treatment failures and is associated with severe complications, such as pelvic inflammatory disease, infertility, preterm birth and foetal infections. This review describes the diagnosis and treatment of AV and the relationship between AV and pregnancy. The characteristics of AV include severely depressed levels of lactobacilli, increased levels of aerobic bacteria and an inflamed vagina. The diagnosis is made by microscopy on wet mounts of fresh vaginal fluid, and some distinct clinical features are recognized. Vaginal suppositories that contain kanamycin or clindamycin have shown curative effects in nonpregnant women. Additionally, the application of topical probiotics can restore the vaginal flora and reduce the recurrence of AV. Clindamycin vaginal suppositories and probiotics may be a better choice for gravida with AV than metronidazole. AV requires prompt attention, and the early diagnosis and treatment of AV during pregnancy significantly improves perinatal outcomes. Further research is needed to define the pathogenesis, diagnostic criteria and standard treatment guidelines for AV.

Open-Loop Audio-Visual Stimulation (AVS): A Useful Tool for Management of Insomnia?

PubMed

Tang, Hsin-Yi Jean; Riegel, Barbara; McCurry, Susan M; Vitiello, Michael V

2016-03-01

Audio Visual Stimulation (AVS), a form of neurofeedback, is a non-pharmacological intervention that has been used for both performance enhancement and symptom management. We review the history of AVS, its two sub-types (close- and open-loop), and discuss its clinical implications. We also describe a promising new application of AVS to improve sleep, and potentially decrease pain. AVS research can be traced back to the late 1800s. AVS's efficacy has been demonstrated for both performance enhancement and symptom management. Although AVS is commonly used in clinical settings, there is limited literature evaluating clinical outcomes and mechanisms of action. One of the challenges to AVS research is the lack of standardized terms, which makes systematic review and literature consolidation difficult. Future studies using AVS as an intervention should; (1) use operational definitions that are consistent with the existing literature, such as AVS, Audio-visual Entrainment, or Light and Sound Stimulation, (2) provide a clear rationale for the chosen training frequency modality, (3) use a randomized controlled design, and (4) follow the Consolidated Standards of Reporting Trials and/or related guidelines when disseminating results.

Development of a membrane of poly (L-co-D,L lactic acid-co-trimethylene carbonate) with aloe vera: An alternative biomaterial designed to improve skin healing.

PubMed

Komatsu, Daniel; Mistura, Daniel V; Motta, Adriana; Domingues, Juliana A; Hausen, Moema A; Duek, Eliana

2017-09-01

The search for new therapies and drugs that act as topical agents to relieve pain and control the infectious processes in burns always attracted interest in clinical trials. As an alternative to synthetic drugs, the use of natural extracts is useful in the development of new strategies and formulations for improving the life quality. The aim of this study was to develop a wound dressing using Poly(L-co-D,L lactic acid-co-TMC) (PLDLA-co-TMC) containing aloe vera (AV). This natural plant extract is known for its modulatory effects under healing process. The membrane of PLDLA-co-TMC+aloe vera was prepared at different concentrations of AV (5, 10, 15 and 50%). The FTIR showed no change in the PLDLA-co-TMC spectrum after AV addition, while the swelling test showed changes only in PLDLA-co-TMC+AV at 50%. The wettability measurements showed decrease in the contact angle in all samples after the AV addition in the polymer, while the AV release test showed that PLDLA-co-TMC+50%AV sample has higher AV release rate than the sample with other AV concentrations. The SEM analysis showed that AV was homogeneously distributed at 5% only. Tensile tests demonstrated an increase in the Young's modulus and a reduction in the elongation till rupture of the PLDLA-co-TMC after the addition of AV. Biocompatibility in vitro evaluation with fibroblast cells seeded in the membranes of PLDLA-co-TMC+AV showed that the cells were able to adhere, proliferate and maintain mitochondrial activity in all AV concentrations tested. Due to the known skin medicinal properties attributed to AV and the results here obtained, we suggest that after in vivo trials, the PLDLA-co-TMC+AV should be a promising biomaterial for application as a device for skin curative and healing agent.

Facts about dextro-Transposition of the Great Arteries (d-TGA)

MedlinePlus

... Septal Defect Atrioventricular Septal Defect Coarctation of the Aorta D-Transposition of the Great Arteries Hypoplastic Left ... the heart – the main pulmonary artery and the aorta – are switched in position, or “transposed.” What is ...

Discovery and characterization of Coturnix chinensis avian β-defensin 10, with broad antibacterial activity.

PubMed

Ma, Deying; Lin, Lijuan; Zhang, Kexin; Han, Zongxi; Shao, Yuhao; Wang, Ruiqin; Liu, Shengwang

2012-04-01

A novel avian β-defensin (AvBD), AvBD10, was discovered in the liver and bone marrow tissues from Chinese painted quail (Coturnix chinensis) in the present study. The complete nucleotide sequence of quail AvBD10 contains a 207-bp open reading frame that encodes 68 amino acids. The quail AvBD10 was expressed widely in all the tissues from quails except the tongue, crop, breast muscle, and thymus and was highly expressed in the bone marrow. In contrast to the expression pattern of AvBD10 in tissues from quail, the chicken AvBD10 was expressed in all 21 tissues from the layer hens investigated, with a high level of expression in the kidney, lung, liver, bone marrow, and Harderian glands. Recombinant glutathione S-transferase (GST)-tagged AvBD10s of both quail and chicken were produced and purified by expression of the two cDNAs in Escherichia coli, respectively. In addition, peptide according to the respective AvBD10s sequence was synthesized, named synthetic AvBD10s. As expected, both recombinant GST-tagged AvBD10s and synthetic AvBD10s of quail and chicken exhibited similar bactericidal properties against most bacteria, including Gram-positive and Gram-negative forms. However, no significant bactericidal activity was found for quail recombinant GST-tagged AvBD10 against Salmonella choleraesuis or for chicken recombinant GST-tagged AvBD10 against Proteus mirabilis. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Social phobia and avoidant personality disorder: similar but different?

PubMed

Lampe, Lisa; Sunderland, Matthew

2015-02-01

Avoidant personality disorder (AvPD) is regarded as a severe variant of social phobia (SP), consistent with a dimensional model. However, these conclusions are largely drawn from studies based on individuals with SP, with or without comorbid AvPD. The present study hypothesized that there are qualitative differences between AvPD and SP that are undermined by limiting research to participants with SP. The authors sought to test this hypothesis by comparing three groups-SP only, AvPD only, and SP+AvPD-using data extracted from an epidemiological sample of 10,641 adults aged 18 years and over. Screening questions were used in the epidemiological survey to identify ICD-10 personality disorders; from this the author developed a proxy measure for DSM-IV AvPD. Axis I diagnoses, including DSM-IV SP, were identified using the Composite International Diagnostic Interview (CIDI). In this sample, the majority of those with AvPD did not also have SP: The authors found 116 persons with AvPD only, 196 with SP only, and 69 with SP+AvPD. There was little difference between any of the groups on sex, marital status, employment, education, or impairment variables. The SP+AvPD group reported more distress and comorbidity than the SP only and AvPD only groups, which did not differentiate from each other. More feared social situations were endorsed in the SP only group compared to the AvPD only group. Although the finding of few differences between SP only and AvPD only groups among the variables measured in this epidemiological survey fails to provide support for the hypothesis of qualitative differences, the finding that the AvPD only group appears more similar to the SP only group than to the SP+AvPD group also fails to provide support for the alternative continuity hypothesis. The greater distress and additional comorbidity with depression associated with SP+AvPD may be due to the additional symptom load of a second disorder rather than simply representing a more severe variant of social phobia. The use of a proxy for AvPD is a limitation of the study. Future studies should focus on broader clinical variables that have been proposed as qualitatively different between these disorders, and on the possible genetic and environmental factors that might help explain such differences.

Are acid volatile sulfides (AVS) important trace metals sinks in semi-arid mangroves?

PubMed

Queiroz, Hermano Melo; Nóbrega, Gabriel Nuto; Otero, Xose L; Ferreira, Tiago Osório

2018-01-01

Acid-volatile sulfides (AVS) formation and its role on trace metals bioavailability were studied in semi-arid mangroves. The semi-arid climatic conditions at the studied sites, marked by low rainfall and high evapotranspiration rates, clearly limited the AVS formation (AVS contents varied from 0.10 to 2.34μmolg -1 ) by favoring oxic conditions (Eh>+350mV). The AVS contents were strongly correlated with reactive iron and organic carbon (r=0.84; r=0.83 respectively), evidencing their dominant role for AVS formation under semi-arid conditions. On the other hand, the recorded ΣSEM/AVS values remained >1 evidencing a little control of AVS over the bioavailability of trace metals and, thus, its minor role as a sink for toxic metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

An ALE meta-analysis on the audiovisual integration of speech signals.

PubMed

Erickson, Laura C; Heeg, Elizabeth; Rauschecker, Josef P; Turkeltaub, Peter E

2014-11-01

The brain improves speech processing through the integration of audiovisual (AV) signals. Situations involving AV speech integration may be crudely dichotomized into those where auditory and visual inputs contain (1) equivalent, complementary signals (validating AV speech) or (2) inconsistent, different signals (conflicting AV speech). This simple framework may allow the systematic examination of broad commonalities and differences between AV neural processes engaged by various experimental paradigms frequently used to study AV speech integration. We conducted an activation likelihood estimation metaanalysis of 22 functional imaging studies comprising 33 experiments, 311 subjects, and 347 foci examining "conflicting" versus "validating" AV speech. Experimental paradigms included content congruency, timing synchrony, and perceptual measures, such as the McGurk effect or synchrony judgments, across AV speech stimulus types (sublexical to sentence). Colocalization of conflicting AV speech experiments revealed consistency across at least two contrast types (e.g., synchrony and congruency) in a network of dorsal stream regions in the frontal, parietal, and temporal lobes. There was consistency across all contrast types (synchrony, congruency, and percept) in the bilateral posterior superior/middle temporal cortex. Although fewer studies were available, validating AV speech experiments were localized to other regions, such as ventral stream visual areas in the occipital and inferior temporal cortex. These results suggest that while equivalent, complementary AV speech signals may evoke activity in regions related to the corroboration of sensory input, conflicting AV speech signals recruit widespread dorsal stream areas likely involved in the resolution of conflicting sensory signals. Copyright © 2014 Wiley Periodicals, Inc.

Avoidant personality disorder versus social phobia: the significance of childhood neglect.

PubMed

Eikenaes, Ingeborg; Egeland, Jens; Hummelen, Benjamin; Wilberg, Theresa

2015-01-01

Avoidant personality disorder (AvPD) and social phobia (SP) are common disorders both in the community and in clinical settings. Whether the two disorders represent different severity levels of social anxiety disorder is currently in dispute. The relationship between AvPD and SP is probably more complex than previously assumed. Several environmental, temperamental, and constitutional factors may play a role in the etiology of AvPD and SP. Better knowledge about childhood experiences may shed light on similarities and differences between the two disorders. The aim of this study was to compare self-reported childhood experiences in AvPD and SP patients. This is a cross-sectional multi-site study of 91 adult patients with AvPD and/ or SP. We compared patients with AvPD with and without SP (AvPD group) to patients with SP without AvPD (SP group). The patients were examined using structured diagnostic interviews and self-report measures, including Child Trauma Questionnaire, Parental Bonding Instrument, and Adult Temperament Questionnaire. Both AvPD and SP were associated with negative childhood experiences. AvPD patients reported more severe childhood neglect than patients with SP, most pronounced for physical neglect. The difference between the disorders in neglect remained significant after controlling for temperamental factors and concurrent abuse. The study indicates that childhood neglect is a risk factor for AvPD and may be one contributing factor to phenomenological differences between AvPD and SP.

Antigenic characterization of intermediate adenovirus 14-11 strains associated with upper respiratory illness in a military camp.

PubMed Central

Hierholzer, J C; Pumarola, A

1976-01-01

An unusual variant of adenovirus (AV) 11 was isolated from throat and rectal swabs from six persons with upper respiratory illness in a Spanish military camp in March 1969. The same strain was serologically related to the upper respiratory illness of seven other men among 25 sample cases studied in detail. After strain purification, the virus was grouped as an AV by standard biological tests; it possessed the usual titers of group-specific hexon antigen but only low hemagglutinin titers (1:4 to 1:8) with erythrocytes from selected rhesus monkeys. The virus gave little reaction in hemagglutination inhibition (HI) tests with antisera to AV 1 through 35, but was neutralized to homologous titers by AV 11 antiserum. Reciprocally, rabbit and guinea pig antisera to the isolates possessed high HI antibody titers to prototype AV 14 and high serum neutralization (SN) antibody titers to prototype AV 11. On this basis, the variants were classified as AV 14-11 intermediates. Sequential serum specimens from the patients with and without positive cultures showed diagnostic rises in HI and SN antibody levels to the AV 14-11 intermediate and to prototype AV 11, but little response to AV 14. PMID:177365

Adrenal Vein Sampling for Conn's Syndrome: Diagnosis and Clinical Outcomes.

PubMed

Deipolyi, Amy R; Bailin, Alexander; Wicky, Stephan; Alansari, Shehab; Oklu, Rahmi

2015-06-19

Adrenal vein sampling (AVS) is the gold standard test to determine unilateral causes of primary aldosteronism (PA). We have retrospectively characterized our experience with AVS including concordance of AVS results and imaging, and describe the approach for the PA patient in whom bilateral AVS is unsuccessful. We reviewed the medical records of 85 patients with PA and compared patients who were treated medically and surgically on pre-procedure presentation and post-treatment outcomes, and evaluated how technically unsuccessful AVS results were used in further patient management. Out of the 92 AVS performed in 85 patients, AVS was technically successful bilaterally in 58 (63%) of cases. Either unsuccessful AVS prompted a repeat AVS, or results from the contralateral side and from CT imaging were used to guide further therapy. Patients who were managed surgically with adrenalectomy had higher initial blood pressure and lower potassium levels compared with patients who were managed medically. Adrenalectomy results in significantly decreased blood pressure and normalization of potassium levels. AVS can identify surgically curable causes of PA, but can be technically challenging. When one adrenal vein fails to be cannulated, results from the contralateral vein can be useful in conjunction with imaging and clinical findings to suggest further management.

Effects of liquid cooling garments on recovery and performance time in individuals performing strenuous work wearing a firefighter ensemble.

PubMed

Kim, Jung-Hyun; Coca, Aitor; Williams, W Jon; Roberge, Raymond J

2011-07-01

This study investigated the effects of body cooling using liquid cooling garments (LCG) on performance time (PT) and recovery in individuals wearing a fully equipped prototype firefighter ensemble (PFE) incorporating a self-contained breathing apparatus (SCBA). Six healthy male participants (three firefighters and three non-firefighters) completed six experimental sessions in an environmental chamber (35°C, 50% relative humidity), consisting of three stages of 15 min exercise at 75% VO2max, and 10 min rest following each exercise stage. During each session, one of the following six conditions was administered in a randomized order: control (no cooling, CON); air ventilation of exhaust SCBA gases rerouted into the PFE (AV); top cooling garment (TCG); TCG combined with AV (TCG+AV); a shortened whole body cooling garment (SCG), and SCG combined with AV (SCG+AV). Results showed that total PT completed was longer under SCG and SCG+AV compared with CON, AV, TCG, and TCG+AV (p<0.01). Magnitude of core temperature (Tc) elevation was significantly decreased when SCG was utilized (p<0.01), and heart rate recovery rate (10 min) was enhanced under SCG, SCG+AV, TCG, and TCG+AV compared with CON (p<0.05). Estimated Esw rate (kg·h(-1)) was the greatest in CON, 1.62 (0.37), and the least in SCG+AV 0.98 (0.44): (descending order: CON>AV>TCG=TCG+AV>SCG>SCG+AV) without a statistical difference between the conditions (p<0.05). Results of the present study suggest that the application of LCG underneath the PFE significantly improves the recovery during a short period of rest and prolongs performance time in subsequent bouts of exercise. LCG also appears to be an effective method for body cooling that promotes heat dissipation during uncompensable heat stress.

The clinical benefit of cardiac resynchronization therapy optimization using a device-based hemodynamic sensor in a patient with dilated cardiomyopathy: a case report.

PubMed

Volpicelli, Mario; Covino, Gregorio; Capogrosso, Paolo

2015-12-19

Results on the evolution of the clinical status of patients undergoing cardiac resynchronization therapy with a defibrillator after automatic optimization of their cardiac resynchronization therapy are scarce. We observed a rapid and important change in the clinical status of our non-responding patient following activation of a sensor capable of weekly atrioventricular and interventricular delays' optimization. A 78-year-old Caucasian man presented with dilated cardiomyopathy, left bundle branch block, a left ventricular ejection fraction of 35 %, New York Heart Association class III/IV heart failure, and paroxysmal atrial fibrillation. Our patient was implanted with a cardiac resynchronization device with a defibrillator and the SonRtip atrial lead. Right ventricular and left ventricular leads were also implanted. Because of the recurrence of atrial fibrillation, the automatic optimization was set off at discharge. Consequently, the device did not optimize atrioventricular and interventricular delays (programming at discharge: 125 ms for the atrioventricular delay and 0 ms for the interventriculardelay). Our patient was treated with an anti-arrhythmic drug. Five months after implantation, his clinical status remained impaired (left ventricular ejection fraction = 30 %). The SonR signal amplitude had also decreased from 0.52 g to 0.29 g. Nevertheless, because our patient was no longer presenting with atrial fibrillation, the anti-arrhythmic treatment was stopped and the SonR optimization system was activated. After 2 months of automatic cardiac resynchronization therapy with defibrillator optimization, our patient's clinical status had significantly improved (left ventricular ejection fraction = 60 %, New York Heart Association class II) and the SonR signal amplitude had doubled shortly after the first weekly automatic optimization. In this non-responding patient, device-based automatic cardiac resynchronization therapy optimization was shown to significantly improve his clinical status.

Surgical Interventions for Atrioventricular Septal Defect Subtypes: The Pediatric Heart Network Experience

PubMed Central

Kaza, Aditya K.; Colan, Steven D.; Jaggers, James; Lu, Minmin; Atz, Andrew M.; Sleeper, Lynn A.; McCrindle, Brian W.; Lambert, Linda M.; Margossian, Renee; Lacro, Ronald V.; Richmond, Marc E.; Natarajan, Shobha; Minich, L. LuAnn

2012-01-01

Background The influence of atrioventricular septal defect (AVSD) subtype on outcomes after repair is poorly understood. Methods Demographic, procedural, and outcome data were obtained 1 and 6 months after AVSD repair in an observational study conducted at 7 North American centers. Results The 215 AVSD patients were subtyped as 60 partial, 27 transitional, 120 complete, and 8 with canal-type VSD. Preoperatively, transitional patients had the highest prevalence of moderate or severe left atrioventricular valve regurgitation (LAVVR, p = 0.01). At repair, complete AVSD and canal-type VSD patients, both with the highest prevalence of trisomy 21 (p < 0.001), were younger (p < 0.001), had lower weight-for-age z scores (p = 0.005), and had more associated cardiac defects (p < 0.001). Annuloplasty was similar among subtypes (p = 0.91), with longer duration of ventilation and hospitalization for complete AVSD (p < 0.001). Independent predictors of moderate or severe LAVVR at the 6-month follow-up were older log(age) at repair (p = 0.02) but not annuloplasty, subtype, or center (p > 0.4). Weight-for-age z scores improved in all subtypes at the 6-month follow-up, and improvement was similar among subtypes (p = 0.17). Conclusions AVSD subtype was significantly associated with patient characteristics and clinical status before repair and influenced age at repair. Significant postoperative LAVVR is the most common sequela, with a similar prevalence across centers 6 months after the intervention. Annuloplasty failed to decrease the postoperative prevalence of moderate or severe LAVVR at 6 months. After accounting for age at repair, AVSD subtype was not associated with postoperative LAVVR severity or growth failure at 6 months. Further investigation is needed to determine if interventional strategies specific to AVSD subtype improve surgical outcomes. PMID:21872212

Worsening atrioventricular conduction after hospital discharge in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: the HORIZONS-AMI trial.

PubMed

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

2017-11-01

The chronic effects of ST-segment elevation myocardial infarction (STEMI) on the atrioventricular conduction (AVC) system have not been elucidated. This study aimed to evaluate the incidence, predictors, and outcomes of worsened AVC post-STEMI in patients treated with a primary percutaneous coronary intervention (PCI). The current analysis included patients from the HORIZONS-AMI trial who underwent primary PCI and had available ECGs. Patients with high-grade atrioventricular block or pacemaker implant at baseline were excluded. Analysis of ECGs excluding the acute hospitalization period indicated worsened AVC in 131 patients (worsened AVC group) and stable AVC in 2833 patients (stable AVC group). Patients with worsened AVC were older, had a higher frequency of hypertension, diabetes, renal insufficiency, previous coronary artery bypass grafting, and predominant left anterior descending culprit lesions. Predictors of worsened AVC included age, hypertension, and previous history of coronary artery disease. Worsened AVC was associated with an increased rate of all-cause death and major adverse cardiac events (death, myocardial infarction, ischemic target vessel revascularization, and stroke) as well as death or reinfarction at 3 years. On multivariable analysis, worsened AVC remained an independent predictor of all-cause death (hazard ratio: 2.005, confidence interval: 1.051-3.827, P=0.0348) and major adverse cardiac events (hazard ratio 1.542, confidence interval: 1.059-2.244, P=0.0238). Progression of AVC system disease in patients with STEMI treated with primary PCI is uncommon, occurs primarily in the setting of anterior myocardial infarction, and portends a high risk for death and major adverse cardiac events.

Atrial isomerism: a surgical experience.

PubMed

Sinzobahamvya, N; Arenz, C; Brecher, A M; Urban, A E

1999-06-01

Most publications on atrial isomerism are autopsy or case reports. The authors review 41 consecutive children operated on from 1980 through to 1996 with emphasis on associated cardiac anomalies, surgical procedures and outcome. Left atrial isomerism was present in 23 patients. Interruption of the inferior vena cava (56%), atrio-ventricular septal defect (47%), common atrium (38%) and cor triatriatum sinistrum (30%) were the most common diagnoses. Biventricular repair was achieved in 17 children and total cavo-pulmonary connection in two. Three underwent staged palliation: modified Blalock-Taussig shunt for two and bidirectional Glenn anastomosis for one. The remainder received a cardiac pacemaker. One patient died early after repair. Two underwent reoperation to correct a regurgitant left atrio-ventricular valve: one of these, in another hospital, had peroperative death. Three died later. Actuarial survival rate after repair and total cavo-pulmonary connection that was stabilized after 2 years was 84%. In the 18 children with right atrial isomerism, pulmonary atresia or stenosis predominated (89%) with discordant ventriculo-arterial connection (72%), atrio-ventricular septal defect (72%), 'single' ventricle (55%) and extracardiac total anomalous pulmonary venous drainage (50%). Biventricular repair was achieved in two patients and complete Fontan circulation in eight. The other eight underwent various staged palliative procedures and correction of extracardiac total anomalous pulmonary venous drainage. Five patients died postoperatively: two in our unit after modified Blalock-Taussig shunt and total cavo-pulmonary connection, three in other hospitals after repair (n = 1) and Fontan (n = 2). Five died later. One was lost for review. Survival after repair and Fontan stabilized after 6 months at 49%. In conclusion, the cardiovascular malformations associated with left atrial isomerism can often be successfully corrected. Those accompanying right atrial isomerism usually preclude a biventricular repair, require staged palliation and carry a poor prognosis.

Long-term outcome in patients receiving permanent pacemaker implantation for atrioventricular block: Comparison of VDD and DDD pacing.

PubMed

Liao, Jo-Nan; Chao, Tze-Fan; Tuan, Ta-Chuan; Kong, Chi-Woon; Chen, Shih-Ann

2016-08-01

A permanent pacemaker (PPM) with dual chamber pacing (DDD) offers atrioventricular synchronization for patients with atrioventricular block (AVB). Single lead atrial synchronous ventricular pacing mode (VDD) is an alternative, but there are concerns about its efficacy and risk of atrial undersensing. Whether VDD can be a good alternative in patients with AVB remains unknown. The aim of the present study was to compare the long-term risk of mortality of VDD with DDD pacing.A total of 207 patients undergoing PPM implantations for AVB with VDD mode were enrolled from 2000 to 2013. Another 828 age- and sex-matched patients undergoing DDD implantations during the same period of time were selected as the control group in a 1 to 4 ratio. The study endpoint was mortality.A total of 1035 patients (64.3% male) were followed up for 46.5 ± 43.2 months. The mean ages were 75.0 years for VDD, and 74.9 years for DDD. The Kaplan-Meier survival analysis showed no significant difference in long-term survival between the VDD and DDD groups (log-rank P = 0.313). After adjustment for baseline characteristics, the VDD and DDD groups had a similar long-term prognosis with an adjusted hazard ratio of 0.875 (P = 0.445). Further analyses for the risk of cardiovascular and noncardiovascular deaths also showed no significant differences between the 2 groups.The long-term prognosis of VDD mode is comparable to that of DDD mode. Single lead VDD can be considered as an alternative choice in patients with AVB without sinus nodal dysfunction.

Long-term outcome in patients receiving permanent pacemaker implantation for atrioventricular block

PubMed Central

Liao, Jo-Nan; Chao, Tze-Fan; Tuan, Ta-Chuan; Kong, Chi-Woon; Chen, Shih-Ann

2016-01-01

Abstract A permanent pacemaker (PPM) with dual chamber pacing (DDD) offers atrioventricular synchronization for patients with atrioventricular block (AVB). Single lead atrial synchronous ventricular pacing mode (VDD) is an alternative, but there are concerns about its efficacy and risk of atrial undersensing. Whether VDD can be a good alternative in patients with AVB remains unknown. The aim of the present study was to compare the long-term risk of mortality of VDD with DDD pacing. A total of 207 patients undergoing PPM implantations for AVB with VDD mode were enrolled from 2000 to 2013. Another 828 age- and sex-matched patients undergoing DDD implantations during the same period of time were selected as the control group in a 1 to 4 ratio. The study endpoint was mortality. A total of 1035 patients (64.3% male) were followed up for 46.5 ± 43.2 months. The mean ages were 75.0 years for VDD, and 74.9 years for DDD. The Kaplan–Meier survival analysis showed no significant difference in long-term survival between the VDD and DDD groups (log-rank P = 0.313). After adjustment for baseline characteristics, the VDD and DDD groups had a similar long-term prognosis with an adjusted hazard ratio of 0.875 (P = 0.445). Further analyses for the risk of cardiovascular and noncardiovascular deaths also showed no significant differences between the 2 groups. The long-term prognosis of VDD mode is comparable to that of DDD mode. Single lead VDD can be considered as an alternative choice in patients with AVB without sinus nodal dysfunction. PMID:27583889

Repair of partial atrioventricular septal defect: a 37-year experience.

PubMed

Buratto, Edward; McCrossan, Brian; Galati, John C; Bullock, Andrew; Kelly, Andrew; d'Udekem, Yves; Brizard, Christian P; Konstantinov, Igor E

2015-05-01

Partial atrioventricular septal defect (pAVSD) is routinely repaired with a low mortality. However, limited data are available on the long-term follow-up of these patients. The current study was designed to determine long-term survival and morbidity of a large cohort of patients operated on at a single institution. From 1975 to 2012, 249 consecutive patients underwent pAVSD repair at the Royal Children's Hospital. The follow-up data were obtained from hospital records, correspondence with cardiologists and primary care physicians, patient surveys and the state death registry. The early mortality rate was 1.2% (3/249), while the long-term survival rate was 96% (95% CI: 93-98%) at 10 years and 94% (95% CI: 89-97%) at 30 years. Freedom from reoperation was 84% at 10 years and 75% at 30 years. The most common reoperations were left atrioventricular valve surgery (30/249, 12.1%), resection of left ventricular outflow tract obstruction (12/249, 4.8%) and closure of residual atrial septal defects (5/249, 2.0%). Implantation of a permanent pacemaker was required in 3.2% (8/249) of patients. Despite a substantial reoperation rate, only 43% of patients older than 18 years of age were seen by a cardiologist within the most recent 2 years of the study period, compared with 80% of those younger than 18 years (P < 0.001). Repair of pAVSD is performed with a low mortality and excellent long-term survival. However, a substantial reoperation rate warrants close follow-up into adulthood. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Long-term outcomes of reoperations following repair of partial atrioventricular septal defect.

PubMed

Buratto, Edward; Ye, Xin Tao; Bullock, Andrew; Kelly, Andrew; d'Udekem, Yves; Brizard, Christian P; Konstantinov, Igor E

2016-08-01

Partial atrioventricular septal defect (pAVSD) is repaired with excellent long-term survival. However, up to 25% of patients require reoperations. This study reviews results of reoperation following pAVSD repair at a single institution. From 1975 to 2012, 40 patients (16%, 40/246) underwent reoperation following pAVSD repair at the study institution. The data were retrospectively reviewed. The mean time to reoperation was 5.4 ± 5.8 years. The most common reoperations were left atrioventricular valve (LAVV) surgery (78%, 31/40) and resection of left ventricular outflow tract obstruction (20%, 8/40). The most common cause for LAVV surgery was regurgitation through the cleft (58%, 18/31), followed by central regurgitation (29%, 9/31). Most cases of LAVV regurgitation were treated by repair (77%, 24/31), rather than replacement (23%, 7/31). Since the introduction of a patch augmentation technique for LAVV repair in 1998, the rate of repair has increased from 54 to 94% (P = 0.012). The early mortality rate was 2.5% (1/40). The survival rate was 90% (95% CI: 76-96) at 10 years and 83% (95% CI: 60-94) at 20 years. The rate of freedom from further reoperation was 66% (95% CI: 46-80) at 10- and 20-year follow-up. The most common cause for reoperation following pAVSD repair was LAVV regurgitation through the LAVV cleft. Reoperation is performed with survival comparable to that of primary pAVSD repair, yet the rate of further reoperations remains high. The patch augmentation technique for LAVVR has significantly increased the rate of successful LAVV repair. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Left Septal Slow Pathway Ablation for Atrioventricular Nodal Reentrant Tachycardia.

PubMed

Katritsis, Demosthenes G; John, Roy M; Latchamsetty, Rakesh; Muthalaly, Rahul G; Zografos, Theodoros; Katritsis, George D; Stevenson, William G; Efimov, Igor R; Morady, Fred

2018-03-01

Immunohistochemistry studies suggest that the anatomic substrate of the slow pathway in atrioventricular nodal reentrant tachycardia (AVNRT) is the left inferior nodal extension. We hypothesized that slow pathway ablation from the left septum is an effective alternative to right-sided ablation. We analyzed our databases of AVNRT in search of cases that had used slow pathway ablation from the left septum because of failure of right septal ablation, and then prospectively subjected consenting patients to a left septal-only procedure. Of 1342 patients subjected to right septal slow pathway ablation for AVNRT, 15 patients, 11 with typical and 4 with atypical AVNRT, had a left septal approach after unsuccessful right-sided ablation (R+L group). Eleven patients were subjected to a left septal-only approach for slow pathway ablation without a previous right septal attempt (L group). Fluoroscopy times in the R+L and L groups were 30.5 (21.0-44.0) and 20.0 (17.0-25.0) minutes, respectively ( P =0.061), and radiofrequency current delivery times were 11.3 (5.0-19.1) and 10.0 (7.0-12.0) minutes, respectively ( P =0.897). There was no need for additional ablation lesions at other anatomic sites in either group, and no cases of atrioventricular block were encountered. Recurrence rates of the arrhythmia for the R+L and L groups were 6.7% and 0%, respectively, in the 3 months after ablation ( P =1.000). Left septal ablation at the anatomic site of the left inferior nodal extension is an alternative for ablation of both typical and atypical AVNRT when ablation at the right posterior septum is ineffective. © 2018 American Heart Association, Inc.

CD142+/CD61+, CD146+ and CD45+ microparticles predict cardiovascular events in high risk patients following a Mediterranean diet supplemented with nuts.

PubMed

Chiva-Blanch, Gemma; Crespo, Javier; Suades, Rosa; Arderiu, Gemma; Padro, Teresa; Vilahur, Gemma; Cubedo, Judith; Corella, Dolores; Salas-Salvadó, Jordi; Arós, Fernando; Martínez-González, Miguel-Angel; Ros, Emilio; Fitó, Montse; Estruch, Ramon; Badimon, Lina

2016-07-04

Circulating microparticles (cMPs) are small phospholipid-rich microvesicles shed by activated cells that play a pivotal role in cell signalling related to the pathogenesis of atherothrombosis. We aimed to investigate the prognostic value of cMPs released from different vascular cells for cardiovascular event (CVE) presentation in asymptomatic patients at high cardiovascular risk factors under nutritional and pharmacologic treatment. This is a nested case-control study of 50 patients from the five-year follow-up prospective PREDIMED trial enrolled in the nuts arm of the Mediterranean diet (MedDiet-nuts). We randomly selected 25 patients who had suffered a CVE during follow-up and pair-matched them for sex, age, and classical CV risk factors to 25 patients who remained asymptomatic (no-CVE). Total Annexin V-(AV)+ cMPs and cMPs from cells of the vascular compartment were quantified by flow cytometry at baseline and after one year follow-up. MedDiet-nuts and pharmacological treatment neither modified levels nor source of MP shedding in CVE patients. However, no-CVE patients showed 40-86 % decreased total AV+, PAC-1+/AV+, CD61+/AV+, CD142+/CD61+/AV+, CD62P+/AV+, CD146+/AV+, CD63+/AV+ and CD11a+/AV+ cMPs at one year follow-up (p≤0.046, all). CD142+/CD61+/AV+, CD146+/AV+ and CD45+/AV+ cMPs were decreased in no-CVE patients compared to CVE patients. A ROC-curve clustered model for CD142+/CD61+/AV+, CD45+/AV+ and CD146+/AV+ cMPs predicted a future CVE [p<0.0001, AUC=0.805 (0.672 to 0.938)]. In patients at high CV risk profile treated with a controlled MedDiet supplemented with nuts and receiving up-to-date CV drug treatment, reduced cMPs derived from activated platelets, leukocytes and endothelial cells are predictive of protection against CVE within the next four years.

The Unusual Resistance of Avian Defensin AvBD7 to Proteolytic Enzymes Preserves Its Antibacterial Activity

PubMed Central

Bailleul, Geoffrey; Kravtzoff, Amanda; Joulin-Giet, Alix; Lecaille, Fabien; Labas, Valérie; Meudal, Hervé; Loth, Karine; Teixeira-Gomes, Ana-Paula; Gilbert, Florence B.; Coquet, Laurent; Jouenne, Thierry; Brömme, Dieter; Schouler, Catherine; Landon, Céline; Lalmanach, Gilles; Lalmanach, Anne-Christine

2016-01-01

Defensins are frontline peptides of mucosal immunity in the animal kingdom, including birds. Their resistance to proteolysis and their ensuing ability to maintain antimicrobial potential remains questionable and was therefore investigated. We have shown by bottom-up mass spectrometry analysis of protein extracts that both avian beta-defensins AvBD2 and AvBD7 were ubiquitously distributed along the chicken gut. Cathepsin B was found by immunoblotting in jejunum, ileum, caecum, and caecal tonsils, while cathepsins K, L, and S were merely identified in caecal tonsils. Hydrolysis product of AvBD2 and AvBD7 incubated with a panel of proteases was analysed by RP-HPLC, mass spectrometry and antimicrobial assays. AvBD2 and AvBD7 were resistant to serine proteases and to cathepsins D and H. Conversely cysteine cathepsins B, K, L, and S degraded AvBD2 and abolished its antibacterial activity. Only cathepsin K cleaved AvBD7 and released Ile4-AvBD7, a N-terminal truncated natural peptidoform of AvBD7 that displayed antibacterial activity. Besides the 3-stranded antiparallel beta-sheet typical of beta-defensins, structural analysis of AvBD7 by two-dimensional NMR spectroscopy highlighted the restricted accessibility of the C-terminus embedded by the N-terminal region and gave a formal evidence of a salt bridge (Asp9-Arg12) that could account for proteolysis resistance. The differential susceptibility of avian defensins to proteolysis opens intriguing questions about a distinctive role in the mucosal immunity against pathogen invasion. PMID:27561012

AVS-1357 inhibits melanogenesis via prolonged ERK activation.

PubMed

Kim, Dong-Seok; Lee, Hyun-Kyung; Park, Seo-Hyoung; Chae, Chong Hak; Park, Kyoung-Chan

2009-08-01

In this study, we demonstrated that a derivative of imidazole, AVS-1357, is a novel skin-whitening compound. AVS-1357 was found to significantly inhibit melanin production in a dose-dependent manner; however, it did not directly inhibit tyrosinase. Furthermore, we found that AVS-1357 induced prolonged activation of extracellular signal-regulated kinase (ERK) and Akt, while it downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase. It has been reported that the activation of ERK and/or Akt is involved in melanogenesis. Therefore, we examined the effects of AVS-1357 on melanogenesis in the absence or presence of PD98059 (a specific inhibitor of the ERK pathway) and/or LY294002 (a specific inhibitor of the Akt pathway). PD98059 dramatically increased melanogenesis, whereas LY294002 had no effect. Furthermore, PD98059 attenuated AVS-1357 induced ERK activation, as well as the downregulation of MITF and tyrosinase. These findings suggest that the effects of AVS-1357 occur via downregulation of MITF and tyrosinase, which is caused by AVS-1357-induced prolonged ERK activation. Taken together, our results indicate that AVS-1357 has the potential as a new skin whitening agent.

Bitopic Sphingosine 1-Phosphate Receptor 3 (S1P3) Antagonist Rescue from Complete Heart Block: Pharmacological and Genetic Evidence for Direct S1P3 Regulation of Mouse Cardiac Conduction.

PubMed

Sanna, M Germana; Vincent, Kevin P; Repetto, Emanuela; Nguyen, Nhan; Brown, Steven J; Abgaryan, Lusine; Riley, Sean W; Leaf, Nora B; Cahalan, Stuart M; Kiosses, William B; Kohno, Yasushi; Brown, Joan Heller; McCulloch, Andrew D; Rosen, Hugh; Gonzalez-Cabrera, Pedro J

2016-01-01

The molecular pharmacology of the G protein-coupled receptors for sphingosine 1-phosphate (S1P) provides important insight into established and new therapeutic targets. A new, potent bitopic S1P3 antagonist, SPM-354, with in vivo activity, has been used, together with S1P3-knockin and S1P3-knockout mice to define the spatial and functional properties of S1P3 in regulating cardiac conduction. We show that S1P3 is a key direct regulator of cardiac rhythm both in vivo and in isolated perfused hearts. 2-Amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol in vivo and S1P in isolated hearts induced a spectrum of cardiac effects, ranging from sinus bradycardia to complete heart block, as measured by a surface electrocardiogram in anesthetized mice and in volume-conducted Langendorff preparations. The agonist effects on complete heart block are absent in S1P3-knockout mice and are reversed in wild-type mice with SPM-354, as characterized and described here. Homologous knockin of S1P3-mCherry is fully functional pharmacologically and is strongly expressed by immunohistochemistry confocal microscopy in Hyperpolarization Activated Cyclic Nucleotide Gated Potassium Channel 4 (HCN4)-positive atrioventricular node and His-Purkinje fibers, with relative less expression in the HCN4-positive sinoatrial node. In Langendorff studies, at constant pressure, SPM-354 restored sinus rhythm in S1P-induced complete heart block and fully reversed S1P-mediated bradycardia. S1P3 distribution and function in the mouse ventricular cardiac conduction system suggest a direct mechanism for heart block risk that should be further studied in humans. A richer understanding of receptor and ligand usage in the pacemaker cells of the cardiac system is likely to be useful in understanding ventricular conduction in health, disease, and pharmacology. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Inappropriate bradycardia in Ebola virus disease.

PubMed

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

2016-08-01

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

Efficient lowering of triglyceride levels in mice by human apoAV protein variants associated with hypertriglyceridemia.

PubMed

Vaessen, Stefan F C; Sierts, Jeroen A; Kuivenhoven, Jan Albert; Schaap, Frank G

2009-02-06

Variation in the apolipoprotein A5 (APOA5) gene has consistently been associated with increased plasma triglyceride (TG) levels in epidemiological studies. In vivo functionality of these variations, however, has thus far not been tested. Using adenoviral over-expression, we evaluated plasma expression levels and TG-lowering efficacies of wild-type human apoAV, two human apoAV variants associated with increased TG (S19W, G185C) and one variant (Q341H) that is predicted to have altered protein function. Injection of mice with adenovirus encoding wild-type or mutant apoAV resulted in an identical dose-dependent elevation of human apoAV levels in plasma. The increase in apoAV levels resulted in pronounced lowering of plasma TG levels at two viral dosages. Unexpectedly, the TG-lowering efficacy of all three apoAV variants was similar to wild-type apoAV. In addition, no effect on TG-hydrolysis-related plasma parameters (free fatty acids, glycerol and post-heparin lipoprotein lipase activity) was apparent upon expression of all apoAV variants. In conclusion, our data indicate that despite their association with hypertriglyceridemia and/or predicted protein dysfunction, the 19W, 185C and 341H apoAV variants are equally effective in reducing plasma TG levels in mice.

Adrenal Vein Sampling for Conn’s Syndrome: Diagnosis and Clinical Outcomes

PubMed Central

Deipolyi, Amy R.; Bailin, Alexander; Wicky, Stephan; Alansari, Shehab; Oklu, Rahmi

2015-01-01

Adrenal vein sampling (AVS) is the gold standard test to determine unilateral causes of primary aldosteronism (PA). We have retrospectively characterized our experience with AVS including concordance of AVS results and imaging, and describe the approach for the PA patient in whom bilateral AVS is unsuccessful. We reviewed the medical records of 85 patients with PA and compared patients who were treated medically and surgically on pre-procedure presentation and post-treatment outcomes, and evaluated how technically unsuccessful AVS results were used in further patient management. Out of the 92 AVS performed in 85 patients, AVS was technically successful bilaterally in 58 (63%) of cases. Either unsuccessful AVS prompted a repeat AVS, or results from the contralateral side and from CT imaging were used to guide further therapy. Patients who were managed surgically with adrenalectomy had higher initial blood pressure and lower potassium levels compared with patients who were managed medically. Adrenalectomy results in significantly decreased blood pressure and normalization of potassium levels. AVS can identify surgically curable causes of PA, but can be technically challenging. When one adrenal vein fails to be cannulated, results from the contralateral vein can be useful in conjunction with imaging and clinical findings to suggest further management. PMID:26854152

Effects of suture position on left ventricular fluid mechanics under mitral valve edge-to-edge repair.

PubMed

Du, Dongxing; Jiang, Song; Wang, Ze; Hu, Yingying; He, Zhaoming

2014-01-01

Mitral valve (MV) edge-to-edge repair (ETER) is a surgical procedure for the correction of mitral valve regurgitation by suturing the free edge of the leaflets. The leaflets are often sutured at three different positions: central, lateral and commissural portions. To study the effects of position of suture on left ventricular (LV) fluid mechanics under mitral valve ETER, a parametric model of MV-LV system during diastole was developed. The distribution and development of vortex and atrio-ventricular pressure under different suture position were investigated. Results show that the MV sutured at central and lateral in ETER creates two vortex rings around two jets, compared with single vortex ring around one jet of the MV sutured at commissure. Smaller total orifices lead to a higher pressure difference across the atrio-ventricular leaflets in diastole. The central suture generates smaller wall shear stresses than the lateral suture, while the commissural suture generated the minimum wall shear stresses in ETER.

Mechanism of valvular regurgitation.

PubMed

Khoo, Nee S; Smallhorn, Jeffery F

2011-10-01

Despite improvements in surgical techniques, valvular regurgitation results in major morbidity in children with heart disease. Functional anatomy, mechanisms of valve closure and adaptation to changing hemodynamic stress in normal mitral and tricuspid valves are complex and only partially understood. As well, pathology of atrioventricular valve regurgitation is further complicated by congenital valve abnormalities involving leaflet tissue, supporting chordal apparatus and displaced papillary muscles. This review provides a current understanding of the mechanisms that result in atrioventricular valve failure. Mitral valve leaflets have contractile elements, in addition to atrial muscle modulation of leaflet tension. When placed under mechanical tethering stress, the mitral valve adapts by leaflet expansion, which increases coaptation surface reserve and chordal thickening. Both pediatric and adult studies are increasingly reporting on the importance of subvalvar apparatus function in maintaining valve competency. The maintenance of efficient valve function is accomplished by a complex series of events involving atrial and annular contraction, annular deformation, active leaflet tension, chordal transmission of papillary muscle contractions and ventricular contraction.

[Limits of cardiac functional adaptation in "top level" resistance athletes].

PubMed

Carù, B; Righetti, G; Bossi, M; Gerosa, C; Gazzotti, G; Maranetto, D

2001-02-01

Sports activity, particularly when performed at high level, provokes cardiovascular adjustments depending on the type of sport and on the level of the load. We evaluated 15 athletes from the Italian national team during a non-agonistic period of cross country skiing, with non-invasive tests including exercise test, color Doppler echocardiography, Holter monitoring, physical examination and standard rest electrocardiogram. Physical examination, rest electrocardiogram, exercise testing and echocardiography were all within the range of the expected values for this type of subjects. Holter monitoring recorded during the periods of agonistic activity revealed significant hypokinetic arrhythmias such as severe bradycardia, pauses, I and II degree atrioventricular blocks, and complete atrioventricular block in 2 cases; these features were not observed on Holter monitoring recorded during the non-agonistic period. The perfect health status of subjects and their racing results may bring about physiological functional adjustments, but these observations suggest the need for a follow-up to evaluate possible pathologic outcomes.

Morphology of the atrioventricular valves and related intraventricular structures in the wild pig (Sus scrofa).

PubMed

Ateş, Sevinç; Karakurum, Emine; Takcı, Lutfi; Başak, Feyza; Kürtül, İbrahim

2017-06-14

Morphology of the atrioventricular valves and the intraventricular related structures were observed and the findings were compared broadly to the literature, in the 7 hearts of the wild pigs (Sus scrofa) by applying macroscopic and microscopic techniques. In all hearts examinated, the tricuspid and mitral valves were precise, composing three and two cusps resepectively. The papillary muscles observed in mammalian heart in general were found in both the ventricles, additionaly there were small unnamed papillary muscles in the left ventricle of the three samples. The septomarginal trabecula and false chords were present in the right ventricles, microscopically possessing myocardial fibers, connective tissue and purkinje cells while the false chords were located in all the left ventricles but the septomarginal trabecula was found in the three samples only. Both the connective tissue and purkinje cells were present in these two structures but the myocardial fibers. Presence of the myocardial fibers in the right ventricle may have an effect on the ventricle geometry.

Interesting Electrophysiological Findings in a Patient With Coincidental Right Ventricular Outflow Tract and Atrioventricular Nodal Reentrant Tachycardia

PubMed Central

Ozin, Bulent; Pirat, Bahar; Muderrisoglu, Haldun

2004-01-01

Tachycardia induced tachycardias are not common in clinical practice, and it is believed that most cases of double tachycardia are coincidental. The existence of two different tachycardias in the same patient almost always poses problems in the electrophysiology laboratory. However, in rare instances, the emergence of a second tachycardia can actually provide invaluable information about the first one. In this report, we describe a 30-year-old woman who presented with palpitations. Electrophysiological study revealed that atrial programmed stimulation at baseline induced right ventricular outflow tract (RVOT) tachycardia and supraventricular tachycardia. The study also showed that each of the tachycardias was able to induce the other. A short run of RVOT tachycardia during supraventricular tachycardia was able to entrain the latter. This finding provided important information about the nature of the supraventricular tachycardia, which proved to be atrioventricular nodal reentrant tachycardia. Both of these tachycardias were successfully ablated, and the patient’s palpitations disappeared. PMID:16943976

Molecular Pathogenesis of Familial Wolff-Parkinson-White Syndrome.

PubMed

Licht, Miyamotoa

2018-01-01

Familial Wolff-Parkinson-White (WPW) syndrome is an autosomal dominant inherited disease and consists of a small percentage of WPW syndrome which exhibits ventricular pre-excitation by development of accessory atrioventricular pathway. A series of mutations in PRKAG2 gene encoding gamma2 subunit of 5'AMP-activated protein kinase (AMPK) has been identified as the cause of familial WPW syndrome. AMPK is one of the most important metabolic regulators of carbohydrates and lipids in many types of tissues including cardiac and skeletal muscles. Patients and animals with the mutation in PRKAG2 gene exhibit aberrant atrioventricular conduction associated with cardiac glycogen overload. Recent studies have revealed "novel" significance of canonical pathways leading to glycogen synthesis and provided us profound insights into molecular mechanism of the regulation of glycogen metabolism by AMPK. This review focuses on the molecular basis of the pathogenesis of cardiac abnormality due to PRKAG2 mutation and will provide current overviews of the mechanism of glycogen regulation by AMPK. J. Med. Invest. 65:1-8, February, 2018.

Awareness and Use of the After-Visit Summary Through a Patient Portal: Evaluation of Patient Characteristics and an Application of the Theory of Planned Behavior.

PubMed

Emani, Srinivas; Healey, Michael; Ting, David Y; Lipsitz, Stuart R; Ramelson, Harley; Suric, Vladimir; Bates, David W

2016-04-13

Patient portals are being used to provide a clinical summary of the office visit or the after-visit summary (AVS) to patients. There has been relatively little research on the characteristics of patients who access the AVS through a patient portal and their beliefs about the AVS. The aim was to (1) assess the characteristics of patients who are aware of and access the AVS through a patient portal and (2) apply the Theory of Planned Behavior (TPB) to predict behavioral intention of patients toward accessing the AVS provided through a patient portal. We developed a survey capturing the components of TPB (beliefs, attitude, perceived norm, and perceived behavioral control). Over a 6-month period, patients with a patient portal account with an office visit in the previous week were identified using our organization's scheduling system. These patients were sent an email about the study and a link to the survey via their portal account. We applied univariate statistical analysis (Pearson chi-square and 1-way ANOVA) to assess differences among groups (aware/unaware of AVS and accessed/did not access AVS). We reported means and standard deviations to depict belief strengths and presented correlations between beliefs and attitude, perceived norm, and perceived behavioral control. We used hierarchical regression analysis to predict behavioral intention toward accessing the AVS through the patient portal. Of the 23,336 patients who were sent the survey, 5370 responded for a response rate of 23.01%. Overall, 76.52% (4109/5370) were aware that the AVS was available through the patient portal and 54.71% of those (2248/4109) accessed the AVS within 5 days of the office visit. Patients who accessed the AVS had a greater number of sessions with the portal (mean 119, SD 221.5) than those who did not access the AVS (mean 79.1, SD 123.3, P<.001); the difference was not significant for awareness of the AVS. The strongest behavioral beliefs with accessing the AVS were being able to track visits and tests (mean 2.53, SD 1.00) followed by having medical information more readily accessible (mean 2.48, SD 1.07). In all, 56.7% of the variance in intention to access the AVS through the portal was accounted for by attitude, perceived norm, and perceived behavioral control. Most users of a patient portal were aware that the AVS was accessible through the portal. Patients had stronger beliefs about accessing the AVS with the goal of timely and efficient access of information than with engaging in their health care. Interventions to improve patient access of the AVS can focus on providers promoting patient beliefs about the value of the AVS for tracking tests and visits, and timely and efficient access of information.

Awareness and Use of the After-Visit Summary Through a Patient Portal: Evaluation of Patient Characteristics and an Application of the Theory of Planned Behavior

PubMed Central

Healey, Michael; Ting, David Y; Lipsitz, Stuart R; Ramelson, Harley; Suric, Vladimir; Bates, David W

2016-01-01

Background Patient portals are being used to provide a clinical summary of the office visit or the after-visit summary (AVS) to patients. There has been relatively little research on the characteristics of patients who access the AVS through a patient portal and their beliefs about the AVS. Objective The aim was to (1) assess the characteristics of patients who are aware of and access the AVS through a patient portal and (2) apply the Theory of Planned Behavior (TPB) to predict behavioral intention of patients toward accessing the AVS provided through a patient portal. Methods We developed a survey capturing the components of TPB (beliefs, attitude, perceived norm, and perceived behavioral control). Over a 6-month period, patients with a patient portal account with an office visit in the previous week were identified using our organization’s scheduling system. These patients were sent an email about the study and a link to the survey via their portal account. We applied univariate statistical analysis (Pearson chi-square and 1-way ANOVA) to assess differences among groups (aware/unaware of AVS and accessed/did not access AVS). We reported means and standard deviations to depict belief strengths and presented correlations between beliefs and attitude, perceived norm, and perceived behavioral control. We used hierarchical regression analysis to predict behavioral intention toward accessing the AVS through the patient portal. Results Of the 23,336 patients who were sent the survey, 5370 responded for a response rate of 23.01%. Overall, 76.52% (4109/5370) were aware that the AVS was available through the patient portal and 54.71% of those (2248/4109) accessed the AVS within 5 days of the office visit. Patients who accessed the AVS had a greater number of sessions with the portal (mean 119, SD 221.5) than those who did not access the AVS (mean 79.1, SD 123.3, P<.001); the difference was not significant for awareness of the AVS. The strongest behavioral beliefs with accessing the AVS were being able to track visits and tests (mean 2.53, SD 1.00) followed by having medical information more readily accessible (mean 2.48, SD 1.07). In all, 56.7% of the variance in intention to access the AVS through the portal was accounted for by attitude, perceived norm, and perceived behavioral control. Conclusions Most users of a patient portal were aware that the AVS was accessible through the portal. Patients had stronger beliefs about accessing the AVS with the goal of timely and efficient access of information than with engaging in their health care. Interventions to improve patient access of the AVS can focus on providers promoting patient beliefs about the value of the AVS for tracking tests and visits, and timely and efficient access of information. PMID:27076485

Using EEG and stimulus context to probe the modelling of auditory-visual speech.

PubMed

Paris, Tim; Kim, Jeesun; Davis, Chris

2016-02-01

We investigated whether internal models of the relationship between lip movements and corresponding speech sounds [Auditory-Visual (AV) speech] could be updated via experience. AV associations were indexed by early and late event related potentials (ERPs) and by oscillatory power and phase locking. Different AV experience was produced via a context manipulation. Participants were presented with valid (the conventional pairing) and invalid AV speech items in either a 'reliable' context (80% AVvalid items) or an 'unreliable' context (80% AVinvalid items). The results showed that for the reliable context, there was N1 facilitation for AV compared to auditory only speech. This N1 facilitation was not affected by AV validity. Later ERPs showed a difference in amplitude between valid and invalid AV speech and there was significant enhancement of power for valid versus invalid AV speech. These response patterns did not change over the context manipulation, suggesting that the internal models of AV speech were not updated by experience. The results also showed that the facilitation of N1 responses did not vary as a function of the salience of visual speech (as previously reported); in post-hoc analyses, it appeared instead that N1 facilitation varied according to the relative time of the acoustic onset, suggesting for AV events N1 may be more sensitive to the relationship of AV timing than form. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Do gender differences in audio-visual benefit and visual influence in audio-visual speech perception emerge with age?

PubMed Central

Alm, Magnus; Behne, Dawn

2015-01-01

Gender and age have been found to affect adults’ audio-visual (AV) speech perception. However, research on adult aging focuses on adults over 60 years, who have an increasing likelihood for cognitive and sensory decline, which may confound positive effects of age-related AV-experience and its interaction with gender. Observed age and gender differences in AV speech perception may also depend on measurement sensitivity and AV task difficulty. Consequently both AV benefit and visual influence were used to measure visual contribution for gender-balanced groups of young (20–30 years) and middle-aged adults (50–60 years) with task difficulty varied using AV syllables from different talkers in alternative auditory backgrounds. Females had better speech-reading performance than males. Whereas no gender differences in AV benefit or visual influence were observed for young adults, visually influenced responses were significantly greater for middle-aged females than middle-aged males. That speech-reading performance did not influence AV benefit may be explained by visual speech extraction and AV integration constituting independent abilities. Contrastingly, the gender difference in visually influenced responses in middle adulthood may reflect an experience-related shift in females’ general AV perceptual strategy. Although young females’ speech-reading proficiency may not readily contribute to greater visual influence, between young and middle-adulthood recurrent confirmation of the contribution of visual cues induced by speech-reading proficiency may gradually shift females AV perceptual strategy toward more visually dominated responses. PMID:26236274

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

Schmelter, Christopher, E-mail: christopher.schmelter@klinikum-ingolstadt.de; Raab, Udo, E-mail: udo.raab@klinikum-ingolstadt.de; Lazarus, Friedrich, E-mail: friedrich.lazarus@klinikum-ingolstadt.de

PurposeThe study was designed to assess outcomes of arteriovenous (AV) accesses after interventional stent-graft deployment in haemodialysis patients.Materials and Methods63 haemodialysis patients with 66 AV fistulas and AV grafts were treated by interventional stent-graft deployment from 2006 to 2012 at our hospital. Data of these patients were retrospectively analysed for location of deployed stent-grafts, occurrence and location of (re-)stenosis and (re-)thrombosis. Complex stenosis was the most frequent indication for stent-graft deployment (45.5 %), followed by complications of angioplasty with vessel rupture or dissection (31.8 %).ResultsA high rate of procedural success was achieved (98.5 %). The most frequent location of the deployed stent-graft wasmore » the draining vein (66.7 %). Stent-graft deployment was more frequent in AV grafts than in AV fistulas. Primary patency was 45.5 % at 6 month, 31.3 % at 12 month and 19.2 % at 24 month. Primary patency was significantly better for AV fistulas than for AV grafts with deployed stent-grafts. Patency of the deployed stent-graft was much better than overall AV access primary patency with deployed stent-graft. Re-stenosis with thrombosis was the most frequent indication for re-intervention. Most frequent location of re-stenosis was the draining vein (37.1 %), followed by stenosis at the AV access (29.5 %) and the deployed stent-graft (23.5 %).ConclusionRe-stenosis and re-thrombosis remain frequent in AV fistulas and AV grafts in haemodialysis patients despite stent-graft deployment. Re-stenosis of the deployed stent-graft is, only in the minority of the cases, responsible for AV access dysfunction.« less

Differential gene expression profiles of β-defensins in the crop, intestine, and spleen using a necrotic enteritis model in 2 commercial broiler chicken lines.

PubMed

Hong, Y H; Song, W; Lee, S H; Lillehoj, H S

2012-05-01

Changes in the expression levels of avian β-defensin (AvBD) mRNA were evaluated in necrotic enteritis (NE) disease model in 2 genetically disparate commercial broiler chicken lines: Ross and Cobb. The NE was initiated in the gut by a previously established co-infection model using oral Eimeria maxima infection followed by a Clostridium perfringens challenge. Among the 14 AvBD types examined, there was a tissue-specific expression of AvBD transcripts: AvBD1, AvBD7, and AvBD9 in the crop; AvBD8, AvBD10, and AvBD13; in the intestine and AvBD1 and AvBD7 in the spleen. The 2 different commercial broiler chicken lines showed differential gene expression patterns of AvBD transcripts following co-infection with E. maxima and C. perfringens, with R-line chickens generally showing higher expression levels than the C strain. Both chicken strains showed enhanced gene expression levels of proinflammatory cytokines, such as IL-1β, IL-6, IL-17F, and TNFSF15 in spleen, and TNFSF15 in intestine, whereas IL-17F was significantly increased only in the intestine of R-line chickens following NE infection. Although the exact nature of interactions between defensins and cytokines in determining the outcome of host innate immune responses to the pathogens of NE remains to be investigated, the differences in gene expression levels of β-defensins and proinflammatory cytokines in the intestine, crop, and spleen could explain the predisposed disease resistance and susceptibility to NE in the 2 commercial broiler chicken lines.

Physician Perceptions and Beliefs about Generating and Providing a Clinical Summary of the Office Visit.

PubMed

Emani, S; Ting, D Y; Healey, M; Lipsitz, S R; Ramelson, H; Suric, V; Bates, D W

2015-01-01

A core measure of the meaningful use of EHR incentive program is the generation and provision of the clinical summary of the office visit, or the after visit summary (AVS), to patients. However, little research has been conducted on physician perceptions and beliefs about the AVS. Evaluate physician perceptions and beliefs about the AVS and the effect of the AVS on workload, patient outcomes, and the care the physician delivers. A cross-sectional online survey of physicians at two academic medical centers (AMCs) in the northeast who are participating in the meaningful use EHR incentive program. Of the 1 795 physicians at both AMCs participating in the incentive program, 853 completed the survey for a response rate of 47.5%. Eighty percent of the respondents reported that the AVS was easy (very easy or quite easy or somewhat easy) to generate and provide to patients. Nonetheless, more than three-fourths of the respondents reported a negative effect of generating and providing the AVS on workload of office staff (78%) and workload of physicians (76%). Primary care physicians had more positive beliefs about the effect of the AVS on patient outcomes than specialists (p<0.001) and also had more positive beliefs about the effect of the AVS on the care they delivered than specialists (p<0.001). Achieving the core meaningful use measure of generating and providing the AVS was easy for physicians but it did not necessarily translate into positive beliefs about the effect of the AVS on patient outcomes or the care the physician delivered. Physicians also had negative beliefs about the effect of the AVS on workload. To promote positive beliefs among physicians around the AVS, organizations should obtain physician input into the design and implementation of the AVS and develop strategies to mitigate its negative impacts on workload.

Adrenal vein sampling in primary aldosteronism: concordance of simultaneous vs sequential sampling.

PubMed

Almarzooqi, Mohamed-Karji; Chagnon, Miguel; Soulez, Gilles; Giroux, Marie-France; Gilbert, Patrick; Oliva, Vincent L; Perreault, Pierre; Bouchard, Louis; Bourdeau, Isabelle; Lacroix, André; Therasse, Eric

2017-02-01

Many investigators believe that basal adrenal venous sampling (AVS) should be done simultaneously, whereas others opt for sequential AVS for simplicity and reduced cost. This study aimed to evaluate the concordance of sequential and simultaneous AVS methods. Between 1989 and 2015, bilateral simultaneous sets of basal AVS were obtained twice within 5 min, in 188 consecutive patients (59 women and 129 men; mean age: 53.4 years). Selectivity was defined by adrenal-to-peripheral cortisol ratio ≥2, and lateralization was defined as an adrenal aldosterone-to-cortisol ratio ≥2, the contralateral side. Sequential AVS was simulated using right sampling at -5 min (t = -5) and left sampling at 0 min (t = 0). There was no significant difference in mean selectivity ratio (P = 0.12 and P = 0.42 for the right and left sides respectively) and in mean lateralization ratio (P = 0.93) between t = -5 and t = 0. Kappa for selectivity between 2 simultaneous AVS was 0.71 (95% CI: 0.60-0.82), whereas it was 0.84 (95% CI: 0.76-0.92) and 0.85 (95% CI: 0.77-0.93) between sequential and simultaneous AVS at respectively -5 min and at 0 min. Kappa for lateralization between 2 simultaneous AVS was 0.84 (95% CI: 0.75-0.93), whereas it was 0.86 (95% CI: 0.78-0.94) and 0.80 (95% CI: 0.71-0.90) between sequential AVS and simultaneous AVS at respectively -5 min at 0 min. Concordance between simultaneous and sequential AVS was not different than that between 2 repeated simultaneous AVS in the same patient. Therefore, a better diagnostic performance is not a good argument to select the AVS method. © 2017 European Society of Endocrinology.

Physician Perceptions and Beliefs about Generating and Providing a Clinical Summary of the Office Visit

PubMed Central

Ting, D.Y.; Healey, M.; Lipsitz, S.R.; Ramelson, H.; Suric, V.; Bates, D.W.

2015-01-01

Summary Background A core measure of the meaningful use of EHR incentive program is the generation and provision of the clinical summary of the office visit, or the after visit summary (AVS), to patients. However, little research has been conducted on physician perceptions and beliefs about the AVS. Objectives Evaluate physician perceptions and beliefs about the AVS and the effect of the AVS on workload, patient outcomes, and the care the physician delivers. Methods A cross-sectional online survey of physicians at two academic medical centers (AMCs) in the northeast who are participating in the meaningful use EHR incentive program. Results Of the 1 795 physicians at both AMCs participating in the incentive program, 853 completed the survey for a response rate of 47.5%. Eighty percent of the respondents reported that the AVS was easy (very easy or quite easy or somewhat easy) to generate and provide to patients. Nonetheless, more than three-fourths of the respondents reported a negative effect of generating and providing the AVS on workload of office staff (78%) and workload of physicians (76%). Primary care physicians had more positive beliefs about the effect of the AVS on patient outcomes than specialists (p<0.001) and also had more positive beliefs about the effect of the AVS on the care they delivered than specialists (p<0.001). Conclusions Achieving the core meaningful use measure of generating and providing the AVS was easy for physicians but it did not necessarily translate into positive beliefs about the effect of the AVS on patient outcomes or the care the physician delivered. Physicians also had negative beliefs about the effect of the AVS on workload. To promote positive beliefs among physicians around the AVS, organizations should obtain physician input into the design and implementation of the AVS and develop strategies to mitigate its negative impacts on workload. PMID:26448799

Evolving Practice Trends of Aortic Root Surgery in North America.

PubMed

Caceres, Manuel; Ma, Yicheng; Rankin, J Scott; Saha-Chaudhuri, Paramita; Gammie, James S; Suri, Rakesh M; Thourani, Vinod H; Englum, Brian R; Esmailian, Fardad; Czer, Lawrence S; Puskas, John D; Svensson, Lars G

2014-08-19

Aortic-valve sparing (AVS) techniques have emerged as alternatives to composite graft-valve replacement (CVR) for treatment of aortic root aneurysm. This study analyzed recent practice trends of aortic root surgery using the Society of Thoracic Surgeons database. From January 2000 through June 2011, 31,747, Overall patients received AVS (n=3,585/31,747; 11.3%) or CVR (n=28,162/31,747; 88.7%). A High-Risk Subgroup was defined as: age >75 years, endocarditis, aortic stenosis, dialysis, multi-valve surgery, valve reoperation, or emergency/salvage status, and high-risk patients were less likely to receive AVS (n=20,356/31,747 [64.1%]; 6% AVS; unadjusted operative mortality 10.5% AVS and 11.7% CVR). The remaining patients comprised a Low-Risk Subgroup, in which AVS was more common (n=11,388/31,747 [35.9%]; 21% AVS; unadjusted operative mortality 1.4% AVS and 3.1% CVR). Procedural changes over 3 equal time periods (P1-P2-P3) were evaluated by Cochran-Armitage trends analysis. Compared to AVS, Overall CVR patients had worse baseline risk profiles and higher unadjusted operative mortality. In High-Risk patients, AVS mortality was comparable to CVR (10.5% vs 11.7%, p=0.19), but AVS mortality was lower in the Low-Risk group (1.4% vs 3%, p<0.0001). For P1/P2/P3, AVS percentages and trend p-values were: High-Risk (6%/6%/7%, p=0.26) and Low-Risk (12%/21%/25%, p<0.0001). CVR prosthesis type (mechanical/bioprosthesis/homograft) also changed: P1 (63%/22%/15%), P2 (58%/38%/4%), and P3 (53%/44%/3%) (all p<0.0001, except mechanical valves in High-Risk patients p=0.18). Patients receiving CVR tended to have higher risk profiles. AVS increased over time in Low-Risk patients while bioprostheses increased in CVR. Favorable outcomes support the trend toward further expansion of AVS. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Designing algorithm visualization on mobile platform: The proposed guidelines

NASA Astrophysics Data System (ADS)

Supli, A. A.; Shiratuddin, N.

2017-09-01

This paper entails an ongoing study about the design guidelines of algorithm visualization (AV) on mobile platform, helping students learning data structures and algorithm (DSA) subject effectively. Our previous review indicated that design guidelines of AV on mobile platform are still few. Mostly, previous guidelines of AV are developed for AV on desktop and website platform. In fact, mobile learning has been proved to enhance engagement in learning circumstances, and thus effect student's performance. In addition, the researchers highly recommend including UI design and Interactivity in designing effective AV system. However, the discussions of these two aspects in previous AV design guidelines are not comprehensive. The UI design in this paper describes the arrangement of AV features in mobile environment, whereas interactivity is about the active learning strategy features based on learning experiences (how to engage learners). Thus, this study main objective is to propose design guidelines of AV on mobile platform (AVOMP) that entails comprehensively UI design and interactivity aspects. These guidelines are developed through content analysis and comparative analysis from various related studies. These guidelines are useful for AV designers to help them constructing AVOMP for various topics on DSA.

Genomic sequence of Heliothis virescens ascovirus 3g isolated from Spodoptera exigua.

PubMed

Huang, Guo-Hua; Wang, Yun-Sheng; Wang, Xing; Garretson, Tyler A; Dai, Liang-Ying; Zhang, Chuan-Xi; Cheng, Xiao-Wen

2012-11-01

Heliothis virescens ascovirus 3a (HvAV-3a), a member of the family Ascoviridae, has the highest diversity among ascovirus species that have been reported in Australia, Indonesia, China, and the United States. To understand the diversity and origin of this important ascovirus, the complete genome of the HvAV Indonesia strain (HvAV-3g), isolated from Spodoptera exigua, was determined to be 199,721 bp, with a G+C content of 45.9%. Therefore, HvAV-3g has the largest genome among the reported ascovirus genomes to date. There are 194 predicted open reading frames (ORFs) encoding proteins of 50 or more amino acid residues. In comparison to HvAV-3e reported from Australia, HvAV-3g has all the ORFs in HvAV-3e with 6 additional ORFs unique to HvAV-3g, including 1 peptidase C26 gene with the highest identity to Drosophila spp. and 2 gas vesicle protein U (GvpU) genes with identities to Bacillus megaterium. The five unique homologous regions (hrs) and 25 baculovirus repeat ORFs (bro) of HvAV-3g are highly variable.

8D.04: CLINICAL BENEFITS OF ADMINISTERING SUPER-SELECTIVE SEGMENTAL ADRENAL VENOUS SAMPLING AND PERFORMING ADRENAL SPARING SURGERY IN THE PATIENTS WITH PRIMARY ALDOSTERONISM.

PubMed

Satoh, F; Morimoto, R; Ono, Y; Iwakura, Y; Omata, K; Kudo, M; Satani, N; Ota, H; Seiji, K; Takase, K; Nakamura, Y; Sasano, H; Ito, S

2015-06-01

Adrenal venous sampling (AVS) has been well known to play pivotal roles in clinical differential diagnosis of unilateral aldosterone producing adenoma (APA) from bilateral idiopathic hyperaldosteronism (IHA). However, it is also true that a central vein AVS or c-AVS which collects the blood from right and left central adrenal veins can by no means discriminate bilateral APA from BHA. There have been no published studies reporting the reliable clinical differential diagnosis between bilateral APA and IHA, especially IHA cases with bilateral non-functioning adenomas (NFA), which has been considered practically impossible in clinical differential diagnosis. As an attempt to this clinical dilemma, segmental AVS (S-AVS), which could evaluate segmental effluents from adrenal tributary veins, has been recently developed. We have performed S-AVS in these patients above following C-AVS, via the insertion of a microcatheter in up to three intra-adrenal first-degree tributary veins on bilateral adrenals. S-AVS did enable us to evaluate the intra-adrenal localization of corticosteroidogenesis. These data did indicate that S-AVS should be performed in the PA patients who had increased aldosterone levels in bilateral central vein and demonstrated space occupying lesions in the bilateral adrenals in order to avoid bilateral adrenalectomy or long lasting medical treatment toward persistent PA. In addition to the situations above, we have administere S-AVS to the following patients; those who had clinically suspected APA but not sufficiently high lateralization indexes according to the results of C-AVS, very young ones with higher clinical probability of recurrence and those who could benefit from partial adrenalectomy by demonstrating the sites of specific steroidogenesis. However, it is also entirely true that S-AVS is more expensive, time-consuming and labor-intensive compared to C-AVS.(Figure is included in full-text article.)The angiography during S-AVS (A, B), the coronal CT image (C), and the data in external iliac vein (EIV), each central vein (1, 4) and each tributary vein (2, 3, 5, 6) of 66 year-old male patient with bilateral APAs. We should carefully select the candidate patients who should undergo S-AVS, which will give a benefit to themselves by demonstrating intra-adrenal steroidogenesis for a safer preserving adrenalectomy.

How TSPSM Implementation has Evolved at AV-8B

DTIC Science & Technology

2008-05-01

How TSPSM Implementation Has Evolved at AV-8B Chris Rickets AV-8B Joint Systems/Software Support Activity (JSSA) Brad Hodgins NAVAIR Systems...members need to be involved) NAVAIR Software/Systems Support Center (NSSC) Slide 40 Contact Information • Chris Rickets (AV-8B Sr. Software Engr...phone: (760) 939-5838 – e-mail: chris rickets @navy mil . . • Brad Hodgins (NAVAIR TSP Coach supporting AV-8B ) – phone: (760) 939-0666/4446 – e

Diagnosis of aerobic vaginitis by quantitative real-time PCR.

PubMed

Rumyantseva, T A; Bellen, G; Savochkina, Y A; Guschin, A E; Donders, G G G

2016-07-01

To evaluate a real-time PCR-based technique to quantify bacteria associated with aerobic vaginitis (AV) as a potential test. Vaginal samples from 100 women were tested by wet-mount microscopy, gram stain and quantitative real-time PCR targeting Enterobacteriacea, Staphylococcus spp., Streptococcus spp., Enterococcus spp., Escherichia coli, Streptococcus agalactiae, S. aureus; Lactobacillus spp. AV diagnosis obtained by wet-mount microscopy was used as reference. Some level of AV was diagnosed in 23 (23.7 %) cases. Various concentrations of Enterobacteriacea, Staphylococcus spp., Streptococcus spp. were detected an all patients. Enterococcus spp. were detected in 76 (78.3 %) cases. Summarized concentrations of aerobes were tenfold higher in AV-positive compared to AV-negative cases [7.30lg vs 6.06lg (p = 0.02)]. Concentrations of aerobes in severe, moderate and light AV cases did not vary significantly (p = 0.14). Concentration of lactobacilli was 1000-fold lower in AV-positive cases compared to normal cases (5.3lg vs 8.3lg, p < 0.0001). Streptococcus spp. dominated in the majority of AV-positive cases [19/22 (86.4 %) samples]. The relation of high loads of aerobes to the low numbers of Lactobacilli are a reliable marker for the presence of AV and could substitute microscopy as a test. PCR may be a good standardized substitution for AV diagnosis in settings where well-trained microscopists are lacking.

Is it useful to repeat an adrenal venous sampling in patients with primary hyperaldosteronism?

PubMed

Bouhanick, B; Delchier, M-C; Fauvel, J; Rousseau, H; Amar, J; Chamontin, B

2014-02-01

Adrenal venous sampling (AVS) is a challenging technical procedure and few patients had AVS procedure twice. To evaluate the reproducibility of the AVS, why AVS were repeated and the conclusions drawn from them. From 1997-2012, 12 patients underwent two AVS. A cortisol level in the adrenal vein greater than or equal to 1.1 to inferior vena cava defined a successful catheterization and a lateralization of secretion corresponded to an aldosterone-to-cortisol vein ratio greater than or equal to 2 between the one side to another. The same side of lateralization of secretion was found in 75% of them. The second AVS were due to technical failure (n=4), unproven lateralization (n=2), a lateralization opposite to the main nodule and ipsilateral to hyperplasia (n=4) on first AVS. For two patients, as the CT was normal, AVS was required again. The second AVS was successful in all patients, including those with an initial technical failure but only patient with technical failure underwent surgery, as BP and kaliemia were controlled. Lateralization on the side of hyperplasia or opposite to the biggest nodule was confirmed in two of four cases. When AVS is unsuccessful for technical reasons, it is worth doing it again but after being sure that surgery is still possibly indicated. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Neural networks supporting audiovisual integration for speech: A large-scale lesion study.

PubMed

Hickok, Gregory; Rogalsky, Corianne; Matchin, William; Basilakos, Alexandra; Cai, Julia; Pillay, Sara; Ferrill, Michelle; Mickelsen, Soren; Anderson, Steven W; Love, Tracy; Binder, Jeffrey; Fridriksson, Julius

2018-06-01

Auditory and visual speech information are often strongly integrated resulting in perceptual enhancements for audiovisual (AV) speech over audio alone and sometimes yielding compelling illusory fusion percepts when AV cues are mismatched, the McGurk-MacDonald effect. Previous research has identified three candidate regions thought to be critical for AV speech integration: the posterior superior temporal sulcus (STS), early auditory cortex, and the posterior inferior frontal gyrus. We assess the causal involvement of these regions (and others) in the first large-scale (N = 100) lesion-based study of AV speech integration. Two primary findings emerged. First, behavioral performance and lesion maps for AV enhancement and illusory fusion measures indicate that classic metrics of AV speech integration are not necessarily measuring the same process. Second, lesions involving superior temporal auditory, lateral occipital visual, and multisensory zones in the STS are the most disruptive to AV speech integration. Further, when AV speech integration fails, the nature of the failure-auditory vs visual capture-can be predicted from the location of the lesions. These findings show that AV speech processing is supported by unimodal auditory and visual cortices as well as multimodal regions such as the STS at their boundary. Motor related frontal regions do not appear to play a role in AV speech integration. Copyright © 2018 Elsevier Ltd. All rights reserved.

The analysis of forms of sulfur in ancient sediments and sedimentary rocks: comments and cautions

USGS Publications Warehouse

Rice, C.A.; Tuttle, M.L.; Reynolds, R.L.

1993-01-01

Assumptions commonly made during analysis of the amount of monosulfides [acid-volatile sulfides (AVS)] and disulfides in modern sediments, may not be valid for ancient sedimentary rocks. It is known that ferric iron can oxidize H2S during AVS analysis unless a reducing agent such as stannous chloride is added to the treatment. In addition, some monosulfides such as greigite and pyrrhotite require heat during the AVS analysis in order to dissolve completely. However, the use of heat and/or stannous chloride in the AVS treatment may partially dissolve disulfides and it is generally recommended that stannous chloride not be used in the AVS treatment for modern sediments. Most of the monosulfides are assumed to be recovered as AVS without the addition of stannous chloride. This study investigates the recovery of monosulfides during sulfur speciation analysis with application to ancient sedimentary rocks. Sulfur in samples containing naturally occurring greigite and mackinawite or pyrite was measured using variations of a common sulfur-speciation scheme. The sulfur-speciation scheme analyzes for monosulfide sulfur, disulfide sulfur, elemental sulfur, inorganic sulfate and organically bound sulfur. The effects of heat, stannous chloride and ferric iron on the amounts of acid-volatile sulfide and disulfide recovered during treatment for AVS were investigated. Isotopic compositions of the recovered sulfur species along with yields from an extended sulfur-speciation scheme were used to quantify the effects. Hot 6 N HCl AVS treatment recovers > 60% of the monosulfides as AVS in samples containing pure greigite and mackinawite. The remaining monosulfide sulfur is recovered in a subsequent elemental sulfur extraction. Hot 6 N HCl plus stannous chloride recovers 100% of the monosulfides as AVS. The addition of ferric iron to pure greigite and mackinawite samples during AVS treatment without stannous chloride decreased the amount of monosulfides recovered as AVS and, if present in great enough concentration, oxidized some of the AVS to a form not recovered in later treatments. The hot stannous chloride AVS treatments dissolve <5% of well-crystallized pyrite in this study. The amount of pyrite dissolved depends on grain size and crystallinity. Greigite in ancient sedimentary rocks was quantitatively recovered as AVS only with hot 6 N HCl plus stannous chloride. Hot 6 N HCl AVS treatment of these rocks did not detect any monosulfides in most samples. A subsequent elemental sulfur extraction did not completely recover the oxidized monosulfides. Therefore, the use of stannous chloride plus heat is recommended in the AVS treatment of ancient sedimentary rocks if monosulfides are present and of interest. All assumptions about the amount of monosulfides and disulfides recovered with the sulfur-speciation scheme used should be verified by extended sulfur-speciation and/or isotopic analysis of the species recovered. ?? 1993.

The social dilemma of autonomous vehicles.

PubMed

Bonnefon, Jean-François; Shariff, Azim; Rahwan, Iyad

2016-06-24

Autonomous vehicles (AVs) should reduce traffic accidents, but they will sometimes have to choose between two evils, such as running over pedestrians or sacrificing themselves and their passenger to save the pedestrians. Defining the algorithms that will help AVs make these moral decisions is a formidable challenge. We found that participants in six Amazon Mechanical Turk studies approved of utilitarian AVs (that is, AVs that sacrifice their passengers for the greater good) and would like others to buy them, but they would themselves prefer to ride in AVs that protect their passengers at all costs. The study participants disapprove of enforcing utilitarian regulations for AVs and would be less willing to buy such an AV. Accordingly, regulating for utilitarian algorithms may paradoxically increase casualties by postponing the adoption of a safer technology. Copyright © 2016, American Association for the Advancement of Science.

Trajectory Optimization of a Bimodal Nuclear Powered Spacecraft to Mars

DTIC Science & Technology

1990-05-29

velocity M = initial mass of spacecraft o m= ion fuel expulsion rate (constant) 0 = thrust direction angle = gravitational constant of Sun AVto t...total velocity change possible for the impulsive engines AV1 = velocity change for Earth escape AV2 = velocity change for Mars capture AVto t = AV + AV

A New Availability-Payment Model for Pricing Performance-Based Logistics Contracts

DTIC Science & Technology

2014-05-01

Petri   net ) is used to  capture concurrency and  synchronization...properties of the  system. Petri   Net Available IN 1`A failure indication IN Down Repair Shop IN Down Replace Order IN Replace Order U costs PC (1,2) time...action (expTime(50*w)); INT Repairs AV Replaces AV AV av.req AV DOWNTIME 0 INT 0 INT Manufacturer Quantity Inventory 5 Quantity stock Cost Book

Equation of state of asymmetric nuclear matter using re-projected nucleon–nucleon potentials

NASA Astrophysics Data System (ADS)

Asadi Aghbolaghi, Z.; Bigdeli, M.

2018-06-01

In this paper, we have calculated the equation of state of asymmetric nuclear matter using the lowest order constrained variational approach and Argonne family potentials with and without three-nucleon interaction (TNI) contribution. In particular, we have used the AV18 potential and the re-projected potentials, AV8‧, and AV6‧. We have also calculated the saturation properties of symmetric nuclear matter, and the nuclear symmetry energy using AV18+TNI, AV8‧+TNI and AV6‧+TNI potentials. The inclusion of TNI has modified the agreement with experiment. We have also made a comparison between our results and those of other many-body calculations.

Replication of Heliothis virescens ascovirus in insect cell lines.

PubMed

Asgari, S

2006-09-01

Ascoviruses (AVs) infect larvae of various insect pests belonging to the family Noctuidae. The result of AV infection in the hosts is cleavage of infected cells into vesicles, a unique feature of AV infection. Since insect cell lines facilitate the study of virus life cycles, attempts were made to analyze Heliothis virescens AV (HvAV3e) infection in several cell lines and compare cell pathology to larval infection. In this study, replication and cytopathological effects of HvAV3e on four different cell lines were investigated. HvAV3e replication was confirmed in three noctuid cell lines from Spodoptera frugiperda (Sf9) and Helicoverpa zea (BCIRL-Hz-AM1 and FB33). However, the virus did not replicate in the non-noctuid insect cell line from Pieris rapae (Pieridae). Despite replication of the virus in the three permissive cell lines, the cytopathological effects of the virus were significantly different from that of larval infection.

Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses.

PubMed

De Lange, H J; Van Griethuysen, C; Koelmans, A A

2008-01-01

Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the disturbance of the sediment. AVS and Simultaneously Extracted Metal (SEM) concentrations were compared to bioassay responses with the freshwater benthic macroinvertebrate Asellus aquaticus. Storage conditions and sediment treatment affected AVS but not SEM levels. AVS can be used as a proxy for sediment disturbance. The best way to pretreat the sediment for use in a bioassay in order to maintain initial AVS conditions was to sample the sediment with an Ekman grab, immediately store it in a jar without headspace, and freeze it as soon as possible. In a survey using seven different sediments, bioassay responses of A. aquaticus were correlated with SEM and AVS characteristics.

Naval Air Development Center Medical Standards for Research Subjects Exposed to Hazardous Aerospace Environments

DTIC Science & Technology

1991-02-01

evidence of isolated hypertrophy compatible with athletic training. c. Left or right bundle branch block. d. Wolff - Parkinson - White or other pre-excitation... syndrome . e. Second or third-degree heart block. (Atrio-ventricular dissociation post-stress is not necessarily disqualifying.) f. QT-prolongation (QTc

The Pattern of Brain Amyloid Load in Posterior Cortical Atrophy Using 18F-AV45: Is Amyloid the Principal Actor in the Disease?

PubMed Central

Beaufils, Emilie; Ribeiro, Maria Joao; Vierron, Emilie; Vercouillie, Johnny; Dufour-Rainfray, Diane; Cottier, Jean-Philippe; Camus, Vincent; Mondon, Karl; Guilloteau, Denis; Hommet, Caroline

2014-01-01

Background Posterior cortical atrophy (PCA) is characterized by progressive higher-order visuoperceptual dysfunction and praxis declines. This syndrome is related to a number of underlying diseases, including, in most cases, Alzheimer's disease (AD). The aim of this study was to compare the amyloid load with 18F-AV45 positron emission tomography (PET) between PCA and AD subjects. Methods We performed 18F-AV45 PET, cerebrospinal fluid (CSF) biomarker analysis and a neuropsychological assessment in 11 PCA patients and 12 AD patients. Results The global and regional 18F-AV45 uptake was similar in the PCA and AD groups. No significant correlation was observed between global 18F-AV45 uptake and CSF biomarkers or between regional 18F-AV45 uptake and cognitive and affective symptoms. Conclusion This 18F-AV45 PET amyloid imaging study showed no specific regional pattern of cortical 18F-AV45 binding in PCA patients. These results confirm that a distinct clinical phenotype in amnestic AD and PCA is not related to amyloid distribution. PMID:25538727

Proteolysis in isolated autophagic vacuoles from the rat pancreas. Effects of chloroquine administration.

PubMed

Yucel-Lindberg, T; Jansson, H; Glaumann, H

1991-01-01

Administration of the antimalaria drug chloroquine increased the number of autophagic vacuoles (AVs) in the rat pancreas. Ultrastructural analysis showed that AVs contained segregated organelles such as mitochondria, zymogen granules, peroxisomes and small portions of cytoplasm. The maximum number of AVs was observed after 3 h of chloroquine treatment. The effect lasted for 12 h and almost disappeared after 16 h. The increase in AVs caused by chloroquine made it possible to isolate them in a discontinuous Metrizamide gradient with high purity. The proteolytic capacity of the AVs isolated after different chloroquine exposure times was measured after prelabeling pancreatic proteins with an injection of L-(1-14C)leucine 16 h before sacrifice. Protein degradation in isolated AVs increased during the first 6 h of chloroquine exposure and then returned to control values 16 h after the administration. In addition, the activities of two lysosomal enzymes, acid phosphatase and cathepsin B, increased in the AV-fractions following chloroquine treatment. It is concluded that the augmented proteolysis in the isolated AVs is due to a combination of increased substrate content and increased proteolytic lysosomal enzyme activities.

Prevalence and treatment of aerobic vaginitis among non-pregnant women: evaluation of the evidence for an underestimated clinical entity.

PubMed

Tansarli, G S; Kostaras, E K; Athanasiou, S; Falagas, M E

2013-08-01

We sought to evaluate the evidence on the prevalence of aerobic vaginitis (AV) among symptomatic non-pregnant women, as well as the treatment administered for this clinical entity. The PubMed and Scopus databases were systematically searched. Sixteen studies met the inclusion criteria, 11 of which reported on the prevalence of possible AV, two on the prevalence of diagnosed AV, and three on the treatment and outcomes of women with diagnosed AV. The prevalence of diagnosed AV varied from 5 to 10.5 %. Streptococcus spp., Staphylococcus aureus, and coagulase-negative staphylococci were the most commonly identified Gram-positive pathogens among women with possible AV, with prevalences of up to 58.7, 41.7, and 37.4 %, respectively, while Escherichia coli was the most common Gram-negative pathogen identified, with a prevalence of up to 23 % among symptomatic women. Regarding antibiotic treatment for AV, the antibiotic schemes administered, which mainly consisted of suppositories of aminoglycosides, showed good effectiveness without serious adverse events provided by any of the included studies. The currently available data suggest that the prevalence of AV is not negligible, while the prevalence of possible AV is considerable. Well-designed studies comparing the prevalence of aerobic pathogens between symptomatic and asymptomatic women are warranted.

[Clinical characteristics of aerobic vaginitis and its mixed infections].

PubMed

Fan, Ai-Ping; Xue, Feng-Xia

2010-12-01

To investigate clinical characteristics of aerobic vaginitis (AV) and its mixed infections for diagnosis efficiently. From April 2008 to December 2008, 516 patients with vaginitis treated in Tianjin Medical University General Hospital were enrolled in this study. AV, bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), trichomonal vaginitis (TV), and cytolytic vaginosis (CV) were diagnosed based on symptoms, sign and vaginal discharge examination. Among 516 cases, AV cases were found in 14.7% (76/516), and AV was common vaginal infection. AV mixed infections was diagnosed in 58% (44/76), including mixed with BV (45%, 20/44), mixed with VVC (30%, 13/44), and mixed with TV (25%, 11/44). Those common symptom of AV were yellow vaginal discharge (63%, 20/32), more vaginal discharge (44%, 14/32). Vaginal pH value was usually more than 4.5 (84%, 27/32). Vaginal cleanliness mainly was grade III - IV (88%, 28/32). Six cases with enterococcus faecium and 4 cases with streptococci were frequently isolated. The symptom and sign of mixed AV infection was atypical. Aerobic vaginitis is a common lower vaginal infection and easily mixed with other pathogens, especially with BV, VVC or TV. When patients were diagnosed with AV or other vaginal infection, it should be mentioned whether those patients have mixed vaginal infection or AV.

Evaluation of a patient-centered after visit summary in primary care.

PubMed

Federman, Alex D; Jandorf, Lina; DeLuca, Joseph; Gover, Mary; Sanchez Munoz, Angela; Chen, Li; Wolf, Michael S; Kannry, Joseph

2018-03-06

To test the impact of a redesigned, patient-centered after visit summary (AVS) on patients' and clinicians' ratings of and experience with the document. We conducted a difference-in-differences (DiD) evaluation of the impact of the redesigned AVS before and after its introduction in an academic primary care practice compared to a concurrent control practice. Outcomes included ratings of the features of the AVS. The intervention site had 118 and 98 patients in the pre- and post-intervention periods and the control site had 99 and 105, respectively. In adjusted DiD analysis, introduction of the patient-centered AVS in the intervention site increased patient reports that the AVS was an effective reminder for taking medications (p = .004) and of receipt of the AVS from clinicians (p = .002). However, they were more likely to perceive it as too long (p = .04). There were no significant changes in overall rating of the AVS by clinicians or their likelihood of providing it to patients. A patient-centered AVS increased the number of patients receiving it and reporting that it would help them remember to take their medications. Improvements in the patient-centeredness of the AVS may improve its usefulness as a document to support self-management in primary care. Copyright © 2018. Published by Elsevier B.V.

[AVS concentrations in Xinan Creek and the influencing factors].

PubMed

Liu, Xiao-Bing; Wen, Yan-Mao; Li, Feng; Wu, Chang-Hua; Duan, Zhi-Peng

2012-07-01

Sediment and overlying water samples were collected at 10 sampling stations at Xinan Creek, a tidal river in Pearl River Delta, and analyzed for physical and chemical characteristics as well as microbial incicators, in order to reveal the main factors dominating the spatial distribution of acid volatile sulfide (AVS). The effects of Eh, SRB OC and TS on the spatial distribution of AVS were investigated and the impact of AVS on the toxicity of heavy metals in the studied area was evaluated. The results showed that the range of AVS was 0.207-41.453 micromol x g(-1), with an average of 6.684 micromol x g(-1), which is relatively high compared to the results in other studies. The AVS value of the surface layer was higher than the bottom layer in 5 stations. The AVS values in both the surface layer and the bottom layer were highly variable, the coefficients of variation being 93.61% and 153.09% , respectively. The analytical results revealed that TS was the factor with the greatest impact on the spatial distribution of AVS, and the order was TS > OC > Eh > SRB. Potential ecological risk of heavy metals existed in 60% of the smpling stations based on the value of Sigma (SEM5-AVS), however, with the criterion of [Sigma(SEM5-AVS)]/foc, none of them had inacceptable ecological risk. Furthermore, in terms of single species of heavy metals, there was certain risk of toxic effect for all the five heavy metals (Cd, Ni, Cu, Zn and Pb). The above mentioned results will provide valuable data for the in-depth study of the formation mechanism of AVS and helpful reference for environmental impact assessment and scientific rehabilitation of heavy metals in polluted rivers.

C-Arm Computed Tomography-Assisted Adrenal Venous Sampling Improved Right Adrenal Vein Cannulation and Sampling Quality in Primary Aldosteronism.

PubMed

Park, Chung Hyun; Hong, Namki; Han, Kichang; Kang, Sang Wook; Lee, Cho Rok; Park, Sungha; Rhee, Yumie

2018-05-04

Adrenal venous sampling (AVS) is a gold standard for subtype classification of primary aldosteronism (PA). However, this procedure has a high failure rate because of the anatomical difficulties in accessing the right adrenal vein. We investigated whether C-arm computed tomography-assisted AVS (C-AVS) could improve the success rate of adrenal sampling. A total of 156 patients, diagnosed with PA who underwent AVS from May 2004 through April 2017, were included. Based on the medical records, we retrospectively compared the overall, left, and right catheterization success rates of adrenal veins during the periods without C-AVS (2004 to 2010, n=32) and with C-AVS (2011 to 2016, n=134). The primary outcome was adequate bilateral sampling defined as a selectivity index (SI) >5. With C-AVS, the rates of adequate bilateral AVS increased from 40.6% to 88.7% (P<0.001), with substantial decreases in failure rates (43.7% to 0.8%, P<0.001). There were significant increases in adequate sampling rates from right (43.7% to 91.9%, P<0.001) and left adrenal veins (53.1% to 95.9%, P<0.001) as well as decreases in catheterization failure from right adrenal vein (9.3% to 0.0%, P<0.001). Net improvement of SI on right side remained significant after adjustment for left side (adjusted SI, 1.1 to 9.0; P=0.038). C-AVS was an independent predictor of adequate bilateral sampling in the multivariate model (odds ratio, 9.01; P<0.001). C-AVS improved the overall success rate of AVS, possibly as a result of better catheterization of right adrenal vein. Copyright © 2018 Korean Endocrine Society.

A NEW CLINICAL PREDICTION CRITERION ACCURATELY DETERMINES A SUBSET OF PATIENTS WITH BILATERAL PRIMARY ALDOSTERONISM BEFORE ADRENAL VENOUS SAMPLING.

PubMed

Kocjan, Tomaz; Janez, Andrej; Stankovic, Milenko; Vidmar, Gaj; Jensterle, Mojca

2016-05-01

Adrenal venous sampling (AVS) is the only available method to distinguish bilateral from unilateral primary aldosteronism (PA). AVS has several drawbacks, so it is reasonable to avoid this procedure when the results would not affect clinical management. Our objective was to identify a clinical criterion that can reliably predict nonlateralized AVS as a surrogate for bilateral PA that is not treated surgically. A retrospective diagnostic cross-sectional study conducted at Slovenian national endocrine referral center included 69 consecutive patients (mean age 56 ± 8 years, 21 females) with PA who underwent AVS. PA was confirmed with the saline infusion test (SIT). AVS was performed sequentially during continuous adrenocorticotrophic hormone (ACTH) infusion. The main outcome measures were variables associated with nonlateralized AVS to derive a clinical prediction rule. Sixty-seven (97%) patients had a successful AVS and were included in the statistical analysis. A total of 39 (58%) patients had nonlateralized AVS. The combined criterion of serum potassium ≥3.5 mmol/L, post-SIT aldosterone <18 ng/dL, and either no or bilateral tumor found on computed tomography (CT) imaging had perfect estimated specificity (and thus 100% positive predictive value) for bilateral PA, saving an estimated 16% of the patients (11/67) from unnecessary AVS. The best overall classification accuracy (50/67 = 75%) was achieved using the post-SIT aldosterone level <18 ng/dL alone, which yielded 74% sensitivity and 75% specificity for predicting nonlateralized AVS. Our clinical prediction criterion appears to accurately determine a subset of patients with bilateral PA who could avoid unnecessary AVS and immediately commence with medical treatment.

Aerobic vaginitis and mixed infections: comparison of clinical and laboratory findings.

PubMed

Fan, Aiping; Yue, Yingli; Geng, Nv; Zhang, Huiying; Wang, Yingmei; Xue, Fengxia

2013-02-01

To investigate the clinical features of aerobic vaginitis (AV) and mixed infections with AV to achieve efficient diagnosis. From April 2008 to August 2009, 657 consecutive outpatients with vaginal symptoms in gynecology clinic in the General Hospital of Tianjin Medical University were investigated. Samples were taken for examination of vaginal discharge and fresh wet mount microscopy. AV, bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), and trichomonal vaginitis (TV) were diagnosed according to standardized definitions. Sixty patients with single AV were randomly selected over the same period. Each patient accepted moxifloxacin therapy. Two kinds of treatment course (400 mg qd, 6 days or 400 mg qd, 12 days) were given. Clinical features and laboratory test results in the first visit and follow-ups were recorded and statistically analyzed. Among the 657 cases, AV was found in 23.74 % of the cases (156/657). AV mixed infections were diagnosed in 53.85 % (84/156): the mixed infections included VVC (32/84, 38.10 %), BV (31/84, 36.90 %), and TV (21/84, 25.00 %). Common symptoms of AV were a change in the characteristics of the discharge (44/72, 61.11 %) and increased discharge (30/72, 41.67 %). Vaginal pH was usually higher than 4.5 (63/72, 87.50 %). Enterococcus faecalis, Streptococcus viridans, Escherichia coli, and Staphylococcus epidermidis were frequently isolated. There is no statistically significant difference between two moxifloxacin treatment groups (p > 0.05). Cure rate was 89.7 % in 6-day group, and 71.4 % in 12-day group. AV is a common vaginal infection, and it is often mixed with other infections, especially VVC, BV and TV. The symptoms and signs of AV mixed infections are atypical. If a patient has vaginal complaints, it is necessary to determine whether AV or mixed infections are present. Oral moxifloxacin is effective in treating AV, and an appropriate course should be selected taking the severity of AV into consideration.

Short-term outcomes after Fab antivenom therapy for severe crotaline snakebite.

PubMed

Lavonas, Eric J; Kokko, Jamie; Schaeffer, Tammi H; Mlynarchek, Sara L; Bogdan, Gregory M; Dart, Richard C

2011-02-01

We seek to determine the short-term outcomes associated with the use of Crotalidae polyvalent immune Fab (ovine) (CroFab; FabAV) therapy for severe crotaline snake envenomation and to better define the incidence of hypersensitivity reactions associated with FabAV use. We conducted a multicenter observational case series study of patients who received FabAV at 17 US hospitals in 2002 to 2004. A 7-point score incorporating local, systemic, and hematologic venom effects was used to grade envenomation severity before and after FabAV therapy. The primary outcome for response to therapy was the change in overall envenomation severity after FabAV administration. The primary safety outcomes were the rates of immediate hypersensitivity reactions and serum sickness. The outcome-evaluable population included 209 patients, of whom 28 had severe envenomation. All severely envenomated patients improved after receiving FabAV. The median severity scores of severely envenomated patients were 5 (interquartile range [IQR] 5 to 5) before FabAV, 1 (IQR 1 to 2) at the last FabAV loading dose, and 1 (IQR 0 to 1) at the last clinical observation. The proportion of patients with progressive pain, progressive swelling, cardiovascular effects, respiratory effects, neurologic effects, gastrointestinal effects, coagulopathy, and thrombocytopenia all improved after FabAV therapy. The safety population included 247 patients. Immediate hypersensitivity reactions were reported in 6.1% (95% confidence interval 3.4% to 9.8%) of patients. Serum sickness was reported in 5% (95% confidence interval 0.6% to 17%) of patients with a minimum of 6 days of follow-up after the last dose of FabAV. FabAV therapy is associated with clinical improvement in severe crotaline snake envenomation. Immediate hypersensitivity and serum sickness rates may be less than described in the FabAV prescribing information. Copyright © 2010. Published by Mosby, Inc.

Elimination of both E1 and E2 from adenovirus vectors further improves prospects for in vivo human gene therapy.

PubMed Central

Gorziglia, M I; Kadan, M J; Yei, S; Lim, J; Lee, G M; Luthra, R; Trapnell, B C

1996-01-01

A novel recombinant adenovirus vector, Av3nBg, was constructed with deletions in adenovirus E1, E2a, and E3 regions and expressing a beta-galactosidase reporter gene. Av3nBg can be propagated at a high titer in a corresponding A549-derived cell line, AE1-2a, which contains the adenovirus E1 and E2a region genes inducibly expressed from separate glucocorticoid-responsive promoters. Av3nBg demonstrated gene transfer and expression comparable to that of Av1nBg, a first-generation adenovirus vector with deletions in E1 and E3. Several lines of evidence suggest that this vector is significantly more attenuated than E1 and E3 deletion vectors. Metabolic DNA labeling studies showed no detectable de novo vector DNA synthesis or accumulation, and metabolic protein labeling demonstrated no detectable de novo hexon protein synthesis for Av3nBg in naive A549 cells even at a multiplicity of infection of up to 3,000 PFU per cell. Additionally, naive A549 cells infected by Av3nBg did not accumulate infectious virions. In contrast, both Av1nBg and Av2Lu vectors showed DNA replication and hexon protein synthesis at multiplicities of infection of 500 PFU per cell. Av2Lu has a deletion in E1 and also carries a temperature-sensitive mutation in E2a. Thus, molecular characterization has demonstrated that the Av3nBg vector is improved with respect to the potential for vector DNA replication and hexon protein expression compared with both first-generation (Av1nBg) and second-generation (Av2Lu) adenoviral vectors. These observations may have important implications for potential use of adenovirus vectors in human gene therapy. PMID:8648763

Audiovisual spoken word training can promote or impede auditory-only perceptual learning: prelingually deafened adults with late-acquired cochlear implants versus normal hearing adults

PubMed Central

Bernstein, Lynne E.; Eberhardt, Silvio P.; Auer, Edward T.

2014-01-01

Training with audiovisual (AV) speech has been shown to promote auditory perceptual learning of vocoded acoustic speech by adults with normal hearing. In Experiment 1, we investigated whether AV speech promotes auditory-only (AO) perceptual learning in prelingually deafened adults with late-acquired cochlear implants. Participants were assigned to learn associations between spoken disyllabic C(=consonant)V(=vowel)CVC non-sense words and non-sense pictures (fribbles), under AV and then AO (AV-AO; or counter-balanced AO then AV, AO-AV, during Periods 1 then 2) training conditions. After training on each list of paired-associates (PA), testing was carried out AO. Across all training, AO PA test scores improved (7.2 percentage points) as did identification of consonants in new untrained CVCVC stimuli (3.5 percentage points). However, there was evidence that AV training impeded immediate AO perceptual learning: During Period-1, training scores across AV and AO conditions were not different, but AO test scores were dramatically lower in the AV-trained participants. During Period-2 AO training, the AV-AO participants obtained significantly higher AO test scores, demonstrating their ability to learn the auditory speech. Across both orders of training, whenever training was AV, AO test scores were significantly lower than training scores. Experiment 2 repeated the procedures with vocoded speech and 43 normal-hearing adults. Following AV training, their AO test scores were as high as or higher than following AO training. Also, their CVCVC identification scores patterned differently than those of the cochlear implant users. In Experiment 1, initial consonants were most accurate, and in Experiment 2, medial consonants were most accurate. We suggest that our results are consistent with a multisensory reverse hierarchy theory, which predicts that, whenever possible, perceivers carry out perceptual tasks immediately based on the experience and biases they bring to the task. We point out that while AV training could be an impediment to immediate unisensory perceptual learning in cochlear implant patients, it was also associated with higher scores during training. PMID:25206344

Comparison of aviary, barn and conventional cage raising of chickens on laying performance and egg quality.

PubMed

Ahammed, M; Chae, B J; Lohakare, J; Keohavong, B; Lee, M H; Lee, S J; Kim, D M; Lee, J Y; Ohh, S J

2014-08-01

This study intended to compare the productive performance of three different layer raising systems; conventional cage (CC), barn (BR) and aviary (AV). The AV is welfare bestowed housing that allows free locomotion for birds within the BR. The BR allows bird's free locomotion inside BR but without multilevel structures. Both pullets and cockerels were housed together in both AV and BR, but only pullets in CC. Seventeen weeks old Lohmann Brown Lite (n = 800) pullets were housed in AV during this study. The same age layer pullets were simultaneously assigned to either at CC or BR to compare egg production performance with AV. The duration of experiment was 40 weeks (from 21st to 60th week). There were no remarkable differences in egg production, hen day egg production (HDEP) and average egg weight among three rearing systems. First 20 weeks (phase-1) average HDEP (%) of AV, CC, and BR were 85.9, 88.8, 87.1 and average egg weights (g) were 57.5, 59.9, and 56.9 respectively. Those of the remaining 20 weeks (phase-2) were 87.1, 87.9, 85.5 and 64.2, 63.0 62.1, respectively. Daily feed intakes (122 g, 110 g, 125 g); feed conversion ratio (2.4, 2.1, 2.5) and daily egg mass (53.9 g, 54.4 g, 52.8 g) data from AV, CC, and BR were not influenced significantly by the respective raising systems. Daily feed intake of layers in both AV (124 g) and BR (127 g) tended to be higher than that in CC (113 g) during phase-2. Overall, exterior egg quality (dirty and cracked eggs) in both phases was superior in BR compared with AV and CC, whereas CC generated intermediate results. This study indicated that the HDEP per se in AV and BR were not significantly different from that in CC. The study implied that the facility depreciation cost for AV and cost for increased feed intake in AV compared to CC are believed to be critical to evaluate the cost effectiveness of egg production in AV.

Audiovisual spoken word training can promote or impede auditory-only perceptual learning: prelingually deafened adults with late-acquired cochlear implants versus normal hearing adults.

PubMed

Bernstein, Lynne E; Eberhardt, Silvio P; Auer, Edward T

2014-01-01

Training with audiovisual (AV) speech has been shown to promote auditory perceptual learning of vocoded acoustic speech by adults with normal hearing. In Experiment 1, we investigated whether AV speech promotes auditory-only (AO) perceptual learning in prelingually deafened adults with late-acquired cochlear implants. Participants were assigned to learn associations between spoken disyllabic C(=consonant)V(=vowel)CVC non-sense words and non-sense pictures (fribbles), under AV and then AO (AV-AO; or counter-balanced AO then AV, AO-AV, during Periods 1 then 2) training conditions. After training on each list of paired-associates (PA), testing was carried out AO. Across all training, AO PA test scores improved (7.2 percentage points) as did identification of consonants in new untrained CVCVC stimuli (3.5 percentage points). However, there was evidence that AV training impeded immediate AO perceptual learning: During Period-1, training scores across AV and AO conditions were not different, but AO test scores were dramatically lower in the AV-trained participants. During Period-2 AO training, the AV-AO participants obtained significantly higher AO test scores, demonstrating their ability to learn the auditory speech. Across both orders of training, whenever training was AV, AO test scores were significantly lower than training scores. Experiment 2 repeated the procedures with vocoded speech and 43 normal-hearing adults. Following AV training, their AO test scores were as high as or higher than following AO training. Also, their CVCVC identification scores patterned differently than those of the cochlear implant users. In Experiment 1, initial consonants were most accurate, and in Experiment 2, medial consonants were most accurate. We suggest that our results are consistent with a multisensory reverse hierarchy theory, which predicts that, whenever possible, perceivers carry out perceptual tasks immediately based on the experience and biases they bring to the task. We point out that while AV training could be an impediment to immediate unisensory perceptual learning in cochlear implant patients, it was also associated with higher scores during training.

Randomized, double-blind, placebo-controlled, safety and immunogenicity study of 4 formulations of Anthrax Vaccine Adsorbed plus CPG 7909 (AV7909) in healthy adult volunteers.

PubMed

Hopkins, Robert J; Daczkowski, Nancy F; Kaptur, Paulina E; Muse, Derek; Sheldon, Eric; LaForce, Craig; Sari, Suha; Rudge, Thomas L; Bernton, Edward

2013-06-26

A new anthrax vaccine that could accelerate the immune response and possibly reduce the number of injections needed for protection would be desirable in a post-exposure setting. This Phase 1 study compared the safety and immunogenicity of 2 IM doses (Days 0 and 14) of 4 formulations of AV7909 (AVA plus CPG 7909) with 2 IM doses of BioThrax(®) (Anthrax Vaccine Adsorbed) and 2 IM doses of saline placebo administered on Days 0 and 14. A total of 105 healthy adults 18-50 years of age were randomized to 1 of 6 study groups: BioThrax (0.5 mL), AV7909 Formulation 1 (0.5 mL AVA+0.5mg CPG 7909), AV7909 Formulation 2 (0.5 mL AVA+0.25mg CPG 7909), AV7909 Formulation 3 (0.25 mL AVA+0.5mg CPG 7909), AV7909 Formulation 4 (0.25 mL AVA+0.25mg CPG 7909), or saline placebo (0.5 mL). All randomized subjects received at least 1 vaccination, and 100 subjects completed the trial. After 2 doses, mean peak normalized toxin neutralizing antibody responses (TNA NF50) in the AV7909 groups were higher than in the BioThrax group. Differences among the 4 AV7909 groups were not statistically significant. Subjects who received AV7909 reached peak titers on Day 28 vs. Day 35 in the BioThrax group. The most common adverse events (AEs) in the BioThrax and AV7909 groups assessed as related to vaccination were injection site reactions. Transient lymphopenia was observed after the first dose in each AV7909 group. Frequencies of injection site and systemic reactions recorded by subjects in diaries for 7 days after each injection were highest with AV7909 Formulation 1. No AEs of special interest (autoimmune events) were observed in the study. Further studies of doses and dosing regimens are planned to assess the immunogenicity and reactogenicity of AV7909. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparison of Aviary, Barn and Conventional Cage Raising of Chickens on Laying Performance and Egg Quality

PubMed Central

Ahammed, M.; Chae, B. J.; Lohakare, J.; Keohavong, B.; Lee, M. H.; Lee, S. J.; Kim, D. M.; Lee, J. Y.; Ohh, S. J.

2014-01-01

This study intended to compare the productive performance of three different layer raising systems; conventional cage (CC), barn (BR) and aviary (AV). The AV is welfare bestowed housing that allows free locomotion for birds within the BR. The BR allows bird’s free locomotion inside BR but without multilevel structures. Both pullets and cockerels were housed together in both AV and BR, but only pullets in CC. Seventeen weeks old Lohmann Brown Lite (n = 800) pullets were housed in AV during this study. The same age layer pullets were simultaneously assigned to either at CC or BR to compare egg production performance with AV. The duration of experiment was 40 weeks (from 21st to 60th week). There were no remarkable differences in egg production, hen day egg production (HDEP) and average egg weight among three rearing systems. First 20 weeks (phase-1) average HDEP (%) of AV, CC, and BR were 85.9, 88.8, 87.1 and average egg weights (g) were 57.5, 59.9, and 56.9 respectively. Those of the remaining 20 weeks (phase-2) were 87.1, 87.9, 85.5 and 64.2, 63.0 62.1, respectively. Daily feed intakes (122 g, 110 g, 125 g); feed conversion ratio (2.4, 2.1, 2.5) and daily egg mass (53.9 g, 54.4 g, 52.8 g) data from AV, CC, and BR were not influenced significantly by the respective raising systems. Daily feed intake of layers in both AV (124 g) and BR (127 g) tended to be higher than that in CC (113 g) during phase-2. Overall, exterior egg quality (dirty and cracked eggs) in both phases was superior in BR compared with AV and CC, whereas CC generated intermediate results. This study indicated that the HDEP per se in AV and BR were not significantly different from that in CC. The study implied that the facility depreciation cost for AV and cost for increased feed intake in AV compared to CC are believed to be critical to evaluate the cost effectiveness of egg production in AV. PMID:25083115

Effect of breed body size and the muscular hypertrophy gene in the production and carcass traits of concentrate-finished yearling bulls.

PubMed

Martínez, A; Aldai, N; Celaya, R; Osoro, K

2010-04-01

To examine the extent of the effect of muscular hypertrophy character in beef of northern-Spanish breeds, animal performance and carcass characteristics of 152 finishing steers from 5 genotypes were studied: 32 yearling bulls from a rustic Asturiana de la Montaña (AM) breed, 96 yearling bulls from Asturiana de los Valles (AV) breed, divided in 3 groups depending on the presence of the gene responsible for double-muscling (i.e., 32 AV mh/mh, 32 AV mh/+, 32 AV +/+), and 24 yearling bulls from AM x AV cross were used. Each genotype was composed of 8 animals per year (4 animals per pen) for 4 yr, except for the AM x AV genotype, which was only evaluated in the last 3 yr of the experiment. All animals were fed indoors with concentrate meal and barley straw ad libitum. Average daily gains in AV animals (1.41 kg/d) were greater (P < 0.01) than in AM (1.12 kg/d), whereas AM x AV were intermediate (1.29 kg/d) to these. No significant differences (P = 0.604) in ADG were found among the 3 AV genotypes. Longer fattening periods (P < 0.001) were taken for AM animals to reach acceptable BW at slaughter. Double-muscled animals (AV mh/mh) were found to have the best feed efficiencies when expressed as G:F (P < 0.001). However, residual feed intake calculated on a daily basis showed a greater efficiency in AV mh/mh and AM than in other genotypes. Carcasses from double-muscled animals had greater BW, yield, conformation and compactness index, and less fat cover than the other genotypes (P < 0.001). Carcasses from AM breed were the lightest and had the worst conformation, whereas those from AM x AV generally presented intermediate characteristics between AV and AM. Double-muscled animals had the greatest LM weight and area. The sixth-rib dissection revealed a greater percentage of muscle (84.6%) and decreased percentages of subcutaneous fat (1.1%), intermuscular fat (4.7%), bone (8.5%), and other tissues (1.2%) in AV mh/mh compared with other genotypes. Water-holding capacity was greatest in AM and least in AV mh/mh. In conclusion, double-muscled AV bulls would provide the greatest economic returns at intensive feeding systems because of their greater efficiency, reduced feeding costs, greater carcass weight and conformation, and greater lean yields, though some LM characteristics (reduced fat content and water-holding capacity) could negatively affect the sensory attributes of the meat compared with other genotypes with greater fatness.

Influence of acid volatile sulfides and metal concentrations on metal partitioning in contaminated sediments

USGS Publications Warehouse

Lee, J.-S.; Lee, B.-G.; Luoma, S.N.; Choi, H.J.; Koh, C.-H.; Brown, C.L.

2000-01-01

The influence of acid volatile sulfide (AVS) on the partitioning of Cd, Ni, and Zn in porewater (PW) and sediment as reactive metals (SEM, simultaneously extracted metals) was investigated in laboratory microcosms. Two spiking procedures were compared, and the effects of vertical geochemical gradients and infaunal activity were evaluated. Sediments were spiked with a Cd-Ni-Zn mixture (0.06, 3, 7.5 ??mol/g, respectively) containing four levels of AVS (0.5, 7.5, 15, 35 ??mol/g). The results were compared to sediments spiked with four levels of Cd-Ni-Zn mixtures at one AVS concentration (7.5 ??mol/g). A vertical redox gradient was generated in each treatment by an 18-d incubation with an oxidized water column. [AVS] in the surface sediments decreased by 65-95% due to oxidation during incubation; initial [AVS] was maintained at 0.5-7.5 cm depth. PW metal concentrations were correlated with [SEM - AVS] among all data. But PW metal concentrations were variable, causing the distribution coefficient, Kd(pw) (the ratio of [SEM] to PW metal concentrations) to vary by 2-3 orders of magnitude at a given [SEM - AVS]. One reason for the variability was that vertical profiles in PW metal concentrations appeared to be influenced by diffusion as well as [SEM - AVS]. The presence of animals appeared to enhance the diffusion of at least Zn. The generalization that PW metal concentrations are controlled by [SEM - AVS] is subject to some important qualifications if vertical gradients are complicated, metal concentrations vary, or equilibration times differ.The influence of acid volatile sulfide (AVS) on the partitioning of Cd, Ni, and Zn in porewater (PW) and sediment as reactive metals (SEM, simultaneously extracted metals) was investigated in laboratory microcosms. Two spiking procedures were compared, and the effects of vertical geochemical gradients and infaunal activity were evaluated. Sediments were spiked with a Cd-Ni-Zn mixture (0.06, 3, 7.5 ??mol/g, respectively) containing four levels of AVS (0.5, 7.5, 15, 35 ??mol/g). The results were compared to sediments spiked with four levels of Cd-Ni-Zn mixtures at one AVS concentration (7.5 ??mol/g). A vertical redox gradient was generated in each treatment by an 18-d incubation with an oxidized water column. [AVS] in the surface sediments decreased by 65-95% due to oxidation during incubation; initial [AVS] was maintained at 0.5-7.5 cm depth. PW metal concentrations were correlated with [SEM - AVS] among all data. But PW metal concentrations were variable, causing the distribution coefficient, Kdpw (the ratio of [SEM] to PW metal concentrations) to vary by 2-3 orders of magnitude at a given [SEM - AVS]. One reason for the variability was that vertical profiles in PW metal concentrations appeared to be influenced by diffusion as well as [SEM - AVS]. The presence of animals appeared to enhance the diffusion of at least Zn. The generalization that PW metal concentrations are controlled by [SEM - AVS] is subject to some important qualifications if vertical gradients are complicated, metal concentrations vary, or equilibration times differ.

KRASH Parametric Sensitivity Study - Transport Category Airplanes

DTIC Science & Technology

1987-12-01

8217_ COPILOT PELVIS w Uj 0 •-’-AV - 24.8 -10 .Y +10 VERTICAL ACCELERATION, -i 0 COPILOT PELVIS uUoAV 4 4 -10 2891 "+15 VERTICAL ACCELERATION...j 0 " -- PILOT PELVIS Uw - - AV =47,9 • ----- 4 -15 AV INCREMENTAL VELOCITY CHANGE, FT/SEC Figure 3-65. DC-7 Test, Measured Acceleration, Eight