Loss Of Atrioventricular Synchrony Research Articles

Therapeutic potential of conduction system pacing as a method for improving cardiac output during ventricular tachycardia.

Ventricular tachycardia (VT) reduces cardiac output through high heart rates, loss of atrioventricular synchrony, and loss of ventricular synchrony. We studied the contribution of each mechanism and explored the potential therapeutic utility of His bundle pacing to improve cardiac output during VT. Study 1 aimed to improve the understanding of mechanisms of harm during VT (using pacing simulated VT). In 23 patients with left ventricular impairment, we recorded continuous ECG and beat-by-beat blood pressure measurements. We assessed the hemodynamic impact of heart rate and restoration of atrial and biventricular synchrony. Study 2 investigated novel pacing interventions during clinical VT by evaluating the hemodynamic effects of His bundle pacing at 5bpm above the VT rate in 10 patients. In Study 1, at progressively higher rates of simulated VT, systolic blood pressure declined: at rates of 125, 160, and 190bpm, -22.2%, -42.0%, and -58.7%, respectively (ANOVA p < 0.0001). Restoring atrial synchrony alone had only a modest beneficial effect on systolic blood pressure (+ 3.6% at 160bpm, p = 0.2117), restoring biventricular synchrony alone had a greater effect (+ 9.1% at 160bpm, p = 0.242), and simultaneously restoring both significantly increased systolic blood pressure (+ 31.6% at 160bpm, p = 0.0003). In Study 2, the mean rate of clinical VT was 143 ± 21bpm. His bundle pacing increased systolic blood pressure by + 14.2% (p = 0.0023). In 6 of 10 patients, VT terminated with His bundle pacing. Restoring atrial and biventricular synchrony improved hemodynamic function in simulated and clinical VT. Conduction system pacing could improve VT tolerability and treatment.

Syncopal storm in an elderly patient: unraveling the mechanism—a case report

BackgroundMultiple episodes of syncope in rapid succession are extremely rare, and syncope in the elderly has multiple potential mechanisms. Even though the electrophysiology study has little role in patients with syncope who have structurally normal hearts, the history of syncope preceded by palpitations was a red-flag symptom that made us go ahead with the electrophysiology study (EP) that revealed the ultimate diagnosis of typical atrioventricular nodal reentry tachycardia (AVNRT), which was documented to be associated with critical hypotension.Case presentationA 78-year-old man with a history of hypertension experienced a ‘Syncopal Storm,’ with four episodes within 15 min. There was no history to suggest common etiologies like postural hypotension or vasovagal syncope. The examination, ECG, and echocardiogram were normal. In view of the nasty sequence and a history of syncope preceded by palpitations, we conducted an electrophysiology study. Surprisingly, typical AVNRT at 190 bpm was easily and repeatedly induced with atrial extrastimuli. During the AVNRT, the systolic BP fell from 160 to 40 mm Hg with the development of presyncope. No ventricular tachycardia was inducible despite vigorous ventricular stimulation protocol. Radiofrequency ablation was performed successfully. The patient was symptom-free after 6 months of follow-up.ConclusionWe report a unique case of a syncopal storm due to AVNRT in the setting of a structurally normal heart. The syncopal storm is a rare but ominous presentation of AVNRT. The cause of syncope was a combination of a high heart rate, loss of atrioventricular synchrony, and an impaired autonomic vasomotor response, causing severe hypotension.

Abstract 12553: Adverse Cardiovascular Outcomes in Heart Failure (HF) With Preserved Systolic Function Associated With Atrial Fibrillation Are Due to Loss of Rhythm Control Impacting HF Status : A Propensity Score Matched Analysis of the TOPCAT Americas Study

Background: Atrial fibrillation (AF) is associated with excess mortality and cardiovascular (CV) hospitalizations in HF patients (pts) with preserved systolic function (pEF), Whether this is due to advanced co-morbidities or loss of atrioventricular (AV) synchrony &amp; rate control in AF is unclear. Hypothesis: To analyze the independent impact of AF on clinical outcomes of HFpEF pts in the TOPCAT AMERICAS study using propensity score matched (PSM) cohorts to account for confounding by other comorbidities. Methods: Study cohorts were matched for 20 clinical, demographic &amp; ECG variables. 3 matched cohorts based on baseline rhythm status at study entry were compared viz. subjects in sinus rhythm (SR), subjects in AF on baseline ECG &amp; subjects with Any AF event by history or ECG. We analyzed CV mortality, adjudicated modes of death &amp; morbidity during a mean follow up period of 2.9 yrs. Results: 418 subjects in SR (SR cohort) were PSM with 418 subjects in AF on baseline ECG (AF on ECG cohort) &amp; 418 pts with any AF event by history or ECG (Any AF cohort) at study entry. Any AF increased risk of CV death(D), pump failure death (PFD), CV and HF hospitalization(H) and HF progression. AF on ECG increased risk of CVD, CVH, HFH and PFD (Tables). Neither AF cohort increased risk of sudden death (SD) {Figure}. Conclusion: 1. AF is an independent risk factor for worsening CV outcomes in HFpEF. 2. This increased risk is due to a selective increase in HF worsening, HFH and PFD rather than SD. 3. Loss of AV synchrony &amp; rate control in AF can independently impact HF progression in HFpEF with consequent HFH and PFD. Restoration of SR may offer benefits for CV outcomes in HFpEF &amp; warrants evaluation.

Atrial fibrillation in cardiac resynchronization therapy.

Patients with atrial fibrillation (AF) were largely excluded from the major clinical trials of cardiac resynchronization therapy (CRT), despite the presence of AF in up to 40% of patients receiving CRT in clinical practice. AF appears to attenuate the response to CRT, by the combination of a reduction in biventricular pacing and the loss of atrioventricular synchrony. In addition, remodeling secondary to CRT may influence the progression of AF. Management options for patients with AF and CRT include rate control, with drugs or atrioventricular node ablation, or rhythm control, with electrical cardioversion and antiarrhythmic therapy, or AF catheter ablation. The evidence for these therapies in patients with CRT is largely limited to observational studies or inferred from randomized studies in the general heart failure population. In this review, we explore the complex interaction between AF, heart failure, and CRT and discuss the evidence for the treatment options in this difficult patient cohort.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

Clinical worsening due to inappropriate automatic mode switch during biventricular pacing: What is the mechanism?

We describe a case of a 65-year-old gentleman with nonischemic cardiomyopathy and left bundle branch block who underwent cardiac resynchronization therapy device. After becoming a responder initially, he experienced significant clinical worsening on follow-up. Device interrogation revealed several long episodes of inappropriate automatic mode switch (AMS) entry due to far-field R wave oversensing resulting in loss of atrioventricular synchrony. Moreover, pacing in VVI mode with consistent VA conduction taking place during the AMS episodes was also found to be detrimental, which helped in sustaining the episodes and produced pacemaker syndrome like phenomenon. Attempts made to resolve the issue by prolonging the post-ventricular atrial blanking period was unsuccessful, hence we adjusted the atrial channel sensitivity to troubleshoot the problem.

The Symptoms and Clinical events associated with Automatic Reprogramming (SCARE) at replacement notification study.

Pacemaker patients experience battery depletion that activates pacemaker's alert for replacement notification. Automatic reprogramming at replacement notification can result in loss of rate response and atrioventricular (AV) synchrony. To determine if relevant symptoms or clinical events may be associated with automatic reprogramming at replacement notification. Electronic medical record review was undertaken for 298 patients referred for pacemaker generator replacement. Primary endpoints were symptoms or clinical events during replacement notification period. Following elimination of duplicate pacemaker replacements (n=12), "near-replacement notification" or "recalled" (n=15) and pacemakers at "end of life" (n=5), 266 subjects were included. Three distinct reprogramming cohorts were identified; those with no change (control) in pacing mode (n=46), those with loss of rate response (n=154), and those with loss of AV synchrony±rate response (n=66). In total, 83 subjects (31.2%) had symptoms with significant differences seen between groups (control=4.3%, loss of rate response=26.0%, loss of AV synchrony±rate response=62.1%, P<0.001). Overall, 28 subjects (10.5%) experienced clinical events with significant differences seen between groups (control=0.0%, loss of rate response=6.5%, loss of AV synchrony±rate response=27.3%, P<0.001). Automatic reprogramming at replacement notification was associated with significant symptoms in 26% of those who lost rate response and in 62% of those who lost AV synchrony±rate response. Additionally, 27% of the latter cohort required nonelective clinical care.

How to Improve Cardiac Resynchronization Therapy Benefit in Atrial Fibrillation Patients: Pulmonary Vein Isolation (and Beyond).

Although cardiac resynchronization therapy (CRT) is an important treatment of symptomatic heart failure patients in sinus rhythm with low left ventricular ejection fraction and ventricular dyssynchrony, its role is not well defined in patients with atrial fibrillation (AF). CRT is not as effective in patients with AF because of inadequate biventricular capture and loss of atrioventricular synchrony. Both can be addressed with catheter ablation of AF. It is still unclear if these therapies offer additive benefits in patients with ventricular dyssynchrony. This article discusses the role and techniques of catheter ablation of AF in patients with heart failure, and its application in CRT recipients.

Comparison of early effects of right ventricular apical pacing on left ventricular functions in single and dual chamber pacemakers

Abstract Objectives Our study aimed to demonstrate the early negative impact of right ventricular apical pacing induced by single (VVI) and dual chamber (DDD) pacemakers on LV functions in patients with preserved EF. And to assess that single brain natriuretic peptide (BNP) after 2 months of implantation is correlated to ventricular dyssynchrony. Methods 40 patients with implanted VVI and DDD pacemakers were examined before implantation and again after 2 and 6 months of implantation for BNP, left ventricular (LV) systolic and diastolic functions by echocardiography and pulsed tissue Doppler. After 6 months, patients with DDD pacemakers were crossed over to VVI mode of pacing for 2 weeks with lower rate programed to 60 beat per minute then sample for BNP was collected again. Results There was no statistically significant difference in LV systolic and diastolic functions except for myocardial performance index (MPI) with ( P value of 0.03). Mean BNP level in VVI pacing was higher than DDD pacing after two months with P value = 0.001 while comparison after 6 months showed P value = 0.023. There was a statistically significant difference between both groups in results of aortic preejection delay (APED) ( P value of r = 0.651 and P value = 0.001) and pacing percentage ( r = 0.687 and P value = 0.00). Conclusion Loss of atrioventricular synchrony in VVI mode leads to a significant difference in LV dyssynchrony between both groups. BNP level is correlated to LV dyssynchrony and pacing percentage.

心房細動に対する低心機能例での抗不整脈薬を用いた洞調律維持療法の現状と再考

心機能低下に伴う心不全例では，心房細動（AF）は最も合併しやすい不整脈として知られている．こうした症例に対する不整脈治療は，以前はジギタリスを使用した心拍数調節（レートコントロール）が主流であったが，近年の薬物・非薬物治療の進歩によって，AFそのものに対する積極的な治療（リズムコントロール）が可能となってきており，除細動を行って洞調律に戻しそれを維持するリズムコントロール治療と，AFのままで心拍数調節を行うレートコントロール治療と，どちらが臨床的に有益なのかが現在重要な課題のひとつとなっている．ここでは大規模試験の結果を紹介し，心機能低下を合併したAFに対する治療ストラテジーを考察する．

Letter Regarding Article, “Symptoms and Functional Status of Patients With Atrial Fibrillation: State of the Art and Future Research Opportunities”

To the Editor: We read with great interest the article by Rienstra et al1 on symptoms and functional status of patients with atrial fibrillation (AF). In their article the authors reviewed in a very systematic and elegant way the current knowledge of a variety of symptoms related to AF. They discussed the relationship between the reduced functional capacity and loss of atrioventricular synchrony and stressed further need for more …

Utility of atrial temporary pacing as an acute treatment for bradyarrhythmias and tachyarrhythmias in the intensive care setting with preservation of atrioventricular synchrony

Temporary pacing is often used as an acute treatment of bradyarrhythmias and suppression of tachyarrhythmias. In patients with cardiogenic shock, loss of atrioventricular synchrony may worsen cardiovascular haemodynamics. We present a series where temporary right atrial pacing was used as an acute treatment for both bradyarrhythmias and tachyarrhythmias.

Use of Ventricular Synchronized Triggered Atrial Pacing to Facilitate Hemodynamic Support During Mapping and Catheter Ablation of Ventricular Vachycardia

Use of VSTAP to Facilitate Hemodynamic Support. The ablation of hemodynamically unstable ventricular tachycardia (VT) is challenging and frequently requires alternative mapping techniques or the use of percutaneous mechanical support devices. Loss of atrioventricular synchrony contributes to hemodynamic compromise during VT. In order to facilitate successful mapping and ablation of unstable VT, we employed ventricular synchronized triggered atrial pacing (VSTAP) at 50% of the RR interval. In this case, triggered atrial pacing permitted activation mapping and, subsequently, successful ablation of the patient's unstable VT. Thus, VSTAP is a readily available and noninvasive technique that may provide adequate hemodynamic support during catheter ablation of unstable VT.

Antiarrhythmic Drug Therapy for Atrial Fibrillation in Patients with Left Ventricular Dysfunction

Atrial fibrillation (AF) is a common rhythm disorder in patients with congestive heart failure (CHF). The prevalence of AF is related to the extent of left ventricular dysfunction and associated with high morbidity and mortality because of an excessive heart rate rise, a loss of atrioventricular synchrony and an irregular ventricular filling. There is also a complex interplay between AF and CHF, with each increasing the morbidity associated with the other. Recent randomized trial (AF-CHF) revealed that no mortality benefit with amiodarone-based rhythm control strategy compared with a rate control strategy. However, in a subgroup study of DIAMOND trial, the maintenance of sinus rhythm at 1 year in patients with low ejection fraction (<35%) was strongly associated with a significant reduction on mortality (RR=0.44). AFFIRM substudy also revealed that if sinus rhythm could be achieved, it was associated with decreased mortality. These data suggested that the treatment approach should be individualized for each patient, with rhythm control strategy being favored when AF is associated with worsening CHF and rate control strategy being reasonable in patients who do not have symptoms related to AF. In this session, we will review current treatment options for AF and heart failure, especially focused on antiarrhythmic drugs.

Postoperative junctional ectopic tachycardia

MOT CLE Tachycardie jonctionnelle ectopique A 3-month-old boy underwent surgery for correction of a ventricular septal defect. Three hours after the intervention the patient developed a regular narrow QRS complex tachycardia (Fig. 1) with a ventricular rate (V) of 195 bpm and slower, regular atrial activity (A) at 150 bpm. The QRS configuration was similar to previous sinus beats. An atrial electrocardiogram recorded by a postoperative temporary atrial epicardial electrode (lead I) clearly demonstrated dissociation between atrial activity (arrows) and ventricular activity (asterisks), leading to the diagnosis of postoperative junctional ectopic tachycardia (JET). The patient was treated with moderate hypothermia and atrial overdrive pacing. The QRS morphology of the paced beats was similar to that observed during the tachycardia. As expected, atrial pacing did not terminate the arrhythmia; however, the haemodynamic status of the patient improved and he recovered sinus rhythm 89 hours after the onset of tachycardia. The patient’s subsequent postoperative course was uneventful, and he has remained free of new arrhythmic events after five years of follow-up. Rapid (> 170 bpm) postoperative JET has been reported after 1% of congenital heart repairs. Its aetiology is thought to be related to mechanical irritation of the proximal conduction system during surgery. Despite being a transient phenomenon, postoperative JET may lead to serious haemodynamic compromise due to elevated heart rate and loss of atrioventricular synchrony. Electrocardiographic features include QRS configuration similar to conducted sinus or atrial paced beats, along with either atrioventricular dissociation with ventricular rate faster than the atrial rate or retrograde conduction. This arrhythmia does not respond to electrical cardioversion, atrial overdrive pacing or intravenous adenosine, and the efficacy of antiarrhythmic drugs is usually

Bradycardia and B-type natriuretic peptide

Bradycardia and loss of atrioventricular synchrony can result inincreased natriuretic peptide secretion due to increased cardiac wall tension. Antihypertensive beta-blocker therapy has been shown to cause elevated natriuretic peptide levels, as well as to increase the frequency of atrial fibrillation in hypertensive patients. The measurement of natriuretic peptides might help solve the clinical challenge of predicting the patients with high risk for beta-blocker induced atrial fibrillation.

Arrhythmias in Adult Patients With Congenital Heart Disease

By the time patients with congenital heart disease (CHD) reach adolescence and early adulthood, rhythm status has often become an active issue, if not the central issue, in their cardiac management. For some, arrhythmias are intrinsic to the structural malformation itself, as is the case with Wolff-Parkinson-White syndrome in the setting of Ebstein’s anomaly, or atrioventricular (AV) block in the setting of “congenitally corrected” transposition of the great arteries (L-TGA). For most other CHD patients, arrhythmias represent an acquired condition related to the unique myocardial substrate created by surgical scars in conjunction with cyanosis and abnormal pressure/volume loads of long duration. This review will attempt to address the major rhythm difficulties faced by adults with CHD, concentrating on electrophysiological features that distinguish CHD from more conventional forms of adult heart disease. A listing of specific arrhythmias and commonly associated congenital defects is provided in Table 1 to serve as an outline for the discussion. View this table: TABLE 1. Specific Arrhythmias and Associated Defects in Adults With Congenital Heart Disease As of 2001, there were estimated to be 800 000 adults with CHD living in the United States,1 a number that has grown steadily as more survivors of childhood surgery reach maturity. Of these, roughly 45% are considered to have mild forms of CHD (eg, atrial septal defect, valvar pulmonary stenosis), 40% are classified as having moderate disease (eg, tetralogy of Fallot, Ebstein’s anomaly), and 15% are considered to have complex disease (eg, single ventricle, transposition of the great arteries). Although arrhythmias can develop within any of the 3 subgroups, the incidence is highest for patients in the moderate and severe categories. Tetralogy of Fallot is an instructive example of moderate CHD with a large arrhythmia burden. As many as one third of patients with repaired tetralogy develop symptomatic atrial tachycardias by …

Treatment of atrial fibrillation by catheter-based procedures.

Catheter-based procedures have been developed with a view to reproduce or improve upon the excellent results of the Maze procedure in the treatment of atrial fibrillation (AF). Linear epicardial lesions created using minimally invasive techniques, or endocardial lesions to encircle the pulmonary veins (PV) have been associated with restoration of sinus rhythm in high percentages of carefully selected patients. The tricuspid-caval isthmus interruption procedure for atrial flutter is highly successful and, in patients who have both atrial flutter and fibrillation, prevents the development of AF when combined with antiarrhythmic agents. Modification of atrioventricular (AV) nodal conduction by eliminating the posterior atrial inputs to the AV node is performed to decrease the ventricular rate and alleviate symptoms during AF without the need for permanent pacing, though may be complicated by inadvertent AV block. AV junctional ablation and permanent pacing alleviates cardiac symptoms, improves quality-of-life, and reduces the use of health care resources. Its constraints include the inescapable need for anticoagulation, loss of AV synchrony, and life-long pacemaker-dependency. The variety of methods and results among published studies strongly emphasises the importance of patient selection, and the relative importance of substrate versus trigger. Possible complications of catheter ablation for AF include systemic thromboembolism, PV stenosis, pericardial effusion, cardiac tamponade, and phrenic nerve paralysis. These remain a matter of concern and stimulate research toward the development of less complex procedures.

Dual-Chamber Pacemakers to Avoid Pacemaker Syndrome

Pacemaker syndrome is an intolerance to ventricular-based (VVIR) pacing due to loss of atrioventricular synchrony. Symptoms can include dyspnea on

Atrial pacing: An alternative treatment for protein-losing enteropathy after the Fontan operation

J Thorac Cardiovasc Surg 2001;121:582-3