Association between COVID-19 vaccination and atrial arrhythmias in individuals with cardiac implantable electronic devices.

INTRODUCTION: The impact of mRNA-based coronavirus disease-2019 (COVID-19) vaccines on atrial arrhythmias (AA) and ventricular arrhythmias incidence is unknown. METHODS: BIOTRONIK Home Monitoring data and Medicare Claims data were utilized to identify individuals implanted with a cardiac implantable electronic device (CIED) between 2010 and 2020 who received one or more doses of COVID-19 vaccine in 2021. The burden of AA (%) in the 3 months postvaccination was compared to those noted in the preceding 3 months using the Wilcoxon signed rank test. Sub-analyses comparing the effects of the influenza vaccine against the COVID-19 vaccine were also evaluated for individuals who received the influenza vaccine in 2020. A 1:1 propensity score match comparison between COVID-19 vaccine and non-vaccinated patients was also performed. RESULTS: First and second doses of the COVID-19 vaccine were administered to 7757 and 6579 individuals with a CIED (age 76.2 ± 9.0 years, 49% males), respectively. While a small but statistically significant increase in the burden of AA was noted in the 3 months postvaccination compared to the preceding 3 months after the first dose of the COVID-19 vaccine (0.43 ± 9.04%, p = .028) a similar rise in AA was found following the influenza vaccine and for matched patients who did not receive the COVID-19 vaccine. No significant difference in device therapies was seen pre- and postvaccination. CONCLUSIONS: Though we report a small but significant increase in the number of CIED-detected AAs following vaccination for COVID-19 over a 3-month window, we believe these results correlate more with time and the progressive nature of AF rather than the vaccine itself. While these data should not dissuade from the use of these vaccines, increased vigilance and prompt treatment of AF is required for high-risk groups, specifically males over 70 years of age, following vaccination.

Oversensing of transthoracic excitation stimuli in contemporary pacemakers.

BACKGROUND: Transthoracic impedance measurements (TIM) is primarily used for minute ventilation rate adaptive sensors in pacemakers. With elevated impedance, the TIM electrical signal itself is oversensed, causing device malfunction. OBJECTIVE: We report an increased incidence of TIM oversensing. METHOD: Retrospective chart review. We review existing records of 18 patients who have demonstrated device malfunction with TIM oversensing. RESULTS: We have found a 1.8% incidence of TIM-related oversensing in our patient population of 959 patients with contemporary Boston Scientific (Marlborough, MA, USA) pacemakers and cardiac resynchronization therapy pacemakers. One patient experienced a syncopal episode. CONCLUSION: Oversensing with pacing inhibition is apparent with the potential of adverse effects to patients.

Implantable Cardioverter Defibrillator Programming Characteristics, Shocked Rhythms, and Survival Among Patients Under Thirty Years of Age.

INTRODUCTION: Indications for implantable cardioverter defibrillators (ICDs) in young patients have expanded and differ from those in older adults. We sought to provide descriptive characteristics and data regarding ICD therapy and outcomes among younger and older ICD recipients. METHODS AND RESULTS: Demographics, device type and programming, remotely transmitted data, shock events, and survival were compared among younger (≤30 years) and older (>30 years) cohorts with ICDs from a single manufacturer followed on a remote network. The younger cohort included 904 patients (1.6% of all implants). This group had more females (46% vs. 25%; P < 0.01), single-coil leads (21% vs. 4%; P < 0.01), and single-chamber devices (46% vs. 34%; P < 0.01). Shock incidence was higher (40% younger vs. 32% older at 4 years; P < 0.01) and survival was better over comparable follow-up (88% vs. 72%; P < 0.01). Remote monitoring was associated with improved survival in both groups (93% vs. 86% ≤ 30 years, P < 0.01; 73% vs. 66% > 30 years, P < 0.01). Shock for polymorphic ventricular tachycardia/fibrillation (VT/VF) was more frequent in younger patients (12% vs. 5%; P < 0.01); 39% of all shocks were inappropriate. A 10-fold increased risk of mortality was seen among young patients with shocks for atrial fibrillation/flutter (AF/AFL). CONCLUSIONS: Differences in survival, shock incidence, and prognostic significance of VT/VF and AF/AFL exist between younger and older ICD recipients. These suggest distinct differences in myocardial substrates and diseases that ultimately impact ICD management.

Femoral approach to lead extraction.

Laser and radiofrequency energy-assisted lead extraction has greatly facilitated this complex procedure. Although success rates are high, in some instances alternate methods of extraction are required. In this review, we discuss techniques for femoral extraction of implanted leads and retained fragments. The major tools available, including commonly used snares and delivery tools, are discussed. We briefly describe combined internal jugular and femoral venous extraction approaches, as well as complimentary utilization of more than one technique via the femoral vein. Animated and procedural sequences are included to help the reader visualize the key components of these techniques.

Clinical presentation and outcomes of cardiovascular implantable electronic device infections in hemodialysis patients.

BACKGROUND: Infection is a serious complication of cardiovascular implantable electronic device (CIED) implantation. Kidney failure is as an independent risk factor for CIED infection and associated mortality. The presence of multiple comorbid conditions may contribute to varied clinical presentations and poor outcomes in hemodialysis (HD)-dependent patients with cardiac device infection. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: CIED infections in HD patients (n=17) and non-HD patients (n=398) at Mayo Clinic in Rochester, MN, between 1991 and 2008. OUTCOMES: Surgical management and death. MEASUREMENTS: Clinical presentations, microbial organisms. RESULTS: Of 415 patients admitted with CIED infection, 17 (4%) were receiving maintenance HD therapy. Among those on HD therapy, mean age was 72±15 (SD) years, 59% were women, and 53% had a central venous catheter for dialysis access. All 17 patients receiving HD therapy presented with CIED-associated bloodstream infection and 41% of these had infected vegetations on CIED leads or cardiac valves. A majority (82%) were managed with complete device removal and almost half (43%) received a replacement device when bloodstream infection cleared. Device infection was associated with significant short-term mortality in HD patients and 90-day survival was only 76% in this group of patients. LIMITATIONS: Smaller sample size, majority white cohort, observational study. CONCLUSIONS: CIED infection in patients receiving HD usually is associated with bloodstream infection and frequently is complicated with device-related endocarditis. Despite complete device removal in the majority of HD patients with infection, mortality remains high.

Cardiac resynchronization therapy: state of the art 2013.

Cardiac resynchronization therapy (CRT) is currently an established device therapy for heart failure (HF) patients. Cumulated knowledge on the pathophysiological mechanisms, implantation techniques, advancement of device-based technologies, and clinical trial experience has impacted on this evolving therapy significantly in the last few years. This article will address the updated CRT guideline and potentially new indications of CRT such as patients with New York Heart Association Class I, normal QRS duration, and non-HF patients with pacing indications. Furthermore, important but unresolved issues will also be discussed which include the impact of QRS morphology and QRS duration on CRT response, new approaches for placement of left ventricular (LV) lead, multisite LV pacing, and the role of HF disease monitoring program.

Performance measures to promote quality improvement in sudden cardiac arrest prevention and treatment.

Sudden cardiac arrest (SCA) is one of the most impactful public health problems in the United States. Despite the progress made in reducing the number of cardiac deaths, the incidence of sudden cardiac death remains high. Studies of life-saving interventions for prevention and treatment of SCA, like ß-blockers, aldosterone antagonists, implantable cardioverter defibrillator therapy, automated external defibrillators, and cardiopulmonary resuscitation, have brought to light substantial underutilization, variations in care, and disparities. Thus, a comprehensive systems-based approach to addressing these gaps in care should be implemented. In addition to educating stakeholders about SCA and its prevention and developing tools that could help physicians identify patients who could benefit from primary prevention of SCA, robust performance measures with strong, evidence-based association between process performance and patient outcomes are needed. In this article, we review the burden of SCA and highlight the need to develop performance measures related to the prevention and treatment of SCA.

Anatomy of the coronary sinus and epicardial coronary venous system in 620 hearts: an electrophysiology perspective.

INTRODUCTION: Cannulation of the coronary sinus (CS) is a prerequisite for left ventricular (LV) pacing and certain ablation procedures. The detailed regional anatomy for the coronary veins and potential anatomic causes for difficulty with these procedures has not been established. METHODS AND RESULTS: Therefore, we performed macroscopic measurements in 620 autopsied hearts (mean age 60 ± 23 years, 44% female). The CS was preserved for analysis in 96%. Sixty-three percent had a Thebesian valve that covered the posterior aspect of the CS ostium with extension to the superior (50%) and inferior aspects (18%) and was obstructive with fenestrations in 3 specimens. Partial or near occlusive valves were present occasionally at the ostium of the great cardiac vein (Vieussens; 8%) and middle cardiac vein (5%). Ninety-three percent had left atrial branches, and 41% had at least one branch with lumen > 3 French. For CRT lead placement, the mid-lateral LV was accessible from the middle cardiac vein (20%), the left posterior vein (92%) or the anterior interventricular vein (86%). Among specimens where the left phrenic nerve was preserved it crossed the LV mid-lateral wall in 45%. CONCLUSIONS: Epicardial coronary vein anatomy is variable, and the mid-lateral LV wall can potentially be accessed through various tributaries of the epicardial veins. The orientation of the Thebesian valve favors cannulation of the CS from an anterior (ventricular) and inferior approach. Anterobasal, mid-lateral, and inferior apical LV coronary veins lie in proximity to the course of the phrenic nerve.

Impact of prior aspirin therapy on clinical manifestations of cardiovascular implantable electronic device infections.

AIMS: Cardiovascular implantable electronic device (CIED) infection may present as pocket infection or as infective endocarditis (CIED-IE) with vegetation on device leads or heart valves. As aspirin has both anti-inflammatory properties and interferes with platelet aggregation, we hypothesized that ongoing anti-platelet therapy with aspirin may impact clinical and echocardiographic manifestations of CIED infection. METHODS AND RESULTS: We retrospectively reviewed 415 cases of CIED infection admitted to Mayo Clinic Rochester from 1991 to 2008. Information regarding aspirin use was available in 392 (94.5%) cases and 178 (45%) had received aspirin therapy prior to clinical onset of CIED infection. Although there were no significant differences in pathogen distribution between patients who had received prior aspirin therapy as compared with those who did not, patients on aspirin therapy were less likely to report chills (25% vs. 35%, P = 0.04), sweats (9% vs.18%, P = 0.01), or have peripheral leukocytosis on admission (33% vs. 46%, P = 0.005). Overall, 82 (21%) of 392 patients met the clinical criteria for CIED-IE. Patients on prior aspirin therapy were significantly less likely to have vegetations on CIED leads or heart valves than those who had not received it (15% vs. 26%, P = 0.01). However, despite the lower frequency of CIED-IE in the aspirin group, there was no significant difference (P = 0.97) in the overall survival between the two groups. CONCLUSION: Aspirin therapy prior to onset of CIED infection was associated with a lower likelihood of vegetation formation on CIED leads or heart valves and associated systemic manifestations of infection.

Longevity of Sprint Fidelis implantable cardioverter-defibrillator leads and risk factors for failure: implications for patient management.

BACKGROUND: Sprint Fidelis (Fidelis) implantable cardioverter-defibrillator leads are prone to fractures that have caused adverse events, primarily inappropriate shocks, and a few reported deaths. More than 100 000 patients have Fidelis leads. No independent multicenter long-term performance information exists for this lead, and single-center studies suggest that certain patients are at increased risk for Fidelis failure. Our aim was to assess the longevity of Fidelis leads and to evaluate clinical variables and adverse events associated with Fidelis failure. The results were compared with like data for Quattro Secure (Quattro) implantable cardioverter-defibrillator leads implanted at our centers. METHODS AND RESULTS: This 3-center study included adults ≥18 years of age who received Fidelis or Quattro leads for the prevention of sudden cardiac death. From November 2001 to January 2009,1023 Fidelis and 1668 Quattro leads were implanted and followed up. The failure rate for Fidelis leads was 2.81%/y compared with 0.43%/y for Quattro leads (P<0.0001). No deaths or injuries occurred as a result of lead failure, but 42% of fractures caused inappropriate shocks. The survival of Fidelis leads at 4 years was 87.0% (95% confidence interval, 83.6 to 90.1) compared with 98.7% (95% confidence interval, 97.9 to 99.4) for Quattro leads (P<0.0001). Multivariate predictors of Fidelis failure were younger age (hazard ratio, 0.98; 95% confidence interval, 0.96 to 0.99), female gender (hazard ratio, 0.61; 95% confidence interval, 0.40 to 1.00), and cardiac disease (P=0.041). CONCLUSIONS: Compared with Quattro leads, the survival of Fidelis leads continues to decline, and Fidelis failure is notably higher in younger patients, women, individuals with hypertrophic cardiomyopathy, and patients with arrhythmogenic right ventricular dysplasia or channelopathies. These findings have significant implications for the management of patients who have Fidelis leads, and they demonstrate the importance of weighing clinical variables in assessments of implantable cardioverter-defibrillator lead performance.

Cardiac resynchronization therapy: do women benefit more than men?

INTRODUCTION: Women are underrepresented in cardiac resynchronization therapy (CRT) trials. Whether there is a gender difference in the benefit derived from CRT has not been well studied. METHODS: This study included 728 consecutive CRT recipients at our institution who met guidelines for placement of a CRT device. Clinical characteristics and echocardiographic parameters were collected at baseline and after CRT; Kaplan-Meier survival analysis was performed using a national death and location database. The effects and outcome of CRT were compared between women and men. RESULTS: Of 728 patients, 166 were female (22.8%). Female patients were younger than male patients (66.0 ± 11.9 years vs 69.4 ± 10.9 years; P < 0.001) and more often had nonischemic cardiomyopathy (68% vs 36%; P < 0.001). Both female and male patients had significantly improved clinical and echocardiographic parameters after CRT. The magnitude of improvement was similar in women and men, except that improvement in New York Heart Association (NYHA) class was greater in women than in men (-0.79 ± 0.78 vs -0.56 ± 0.85; P = 0.009). Although women were at lower risk of death than men after CRT (hazard ratio, 0.51; 95% confidence interval, 0.35-0.75; P < 0.001, unadjusted), multivariate analysis indicated gender was not, but age at CRT placement, cardiomyopathy cause, NYHA class, and lead location were independent predictors of survival. CONCLUSION: Female CRT recipients seem to achieve greater survival benefit than male recipients. However, this benefit is majorly driven by nonischemic cardiomyopathy and other clinical factors.

ISHNE/EHRA expert consensus on remote monitoring of cardiovascular implantable electronic devices (CIEDs).

We are in the midst of a rapidly evolving era of technology-assisted medicine. The field of telemedicine provides the opportunity for highly individualized medical management in a way that has never been possible before. Evolving medical technologies using cardiac implantable devices (CIEDs) with capabilities for remote monitoring permit evaluation of multiple parameters of cardiovascular physiology and risk, including cardiac rhythm, device function, blood pressure values, the presence of myocardial ischaemia, and the degree of compensation of congestive heart failure. Cardiac risk, device status, and response to therapies can now be assessed with these electronic systems of detection and reporting. This document reflects the extensive experience from investigators and innovators around the world who are shaping the evolution of this rapidly expanding field, focusing in particular on implantable pacemakers (IPGs), implantable cardioverter-defibrillators (ICDs), devices for cardiac resynchronization therapy (CRT) (both, with and without defibrillation properties), loop recorders, and haemodynamic monitoring devices. This document covers the basic methodologies, guidelines for their use, experience with existing applications, and the legal and reimbursement aspects associated with their use. To adequately cover this important emerging topic, the International Society for Holter and Noninvasive Electrocardiology (ISHNE) and the European Heart Rhythm Association (EHRA) combined their expertise in this field. We hope that the development of this field can contribute to improve care of our cardiovascular patients.

Impact of radiocontrast use during left ventricular pacemaker lead implantation for cardiac resynchronization therapy.

AIMS: The risk of contrast-induced nephropathy (CIN) with radiocontrast use during left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT) is unknown. It is unclear as to whether minimizing contrast use impacts adequacy of LV lead placement. METHODS AND RESULTS: A retrospective analysis was performed of all LV leads placed for CRT at Mayo Clinic, Rochester, MN from 16 March 2001 to 1 April 2009. The primary goal was to assess risk of CIN and adequacy of lead placement depending on the amount of contrast administered during CRT placement. Contrast-induced nephropathy was defined as a ≥25% increase in serum creatinine ≥48 h post-procedurally. Adequacy of lead placement was assessed in a blinded fashion by review of procedural fluoroscopic and post-procedural radiographic images. Eight hundred and twenty-two subjects were divided based on the amount of procedural contrast used into tertile 1 (<55 mL, 257 patients), tertile 2 (55-94 mL, 261 patients), and tertile 3 (≥95 mL, 304 patients). Contrast-induced nephropathy occurred in 5.4% of patients in tertile 1, 5.4% in tertile 2 and 11.8% in tertile 3 (P = 0.004). Among the tertiles, lead positioning was optimal in 95, 80 and 66%, respectively (P < 0.0001). Fluoroscopic time was 34 ± 23, 42 ± 26, and 48 ± 30 min in tertiles 1, 2, and 3 (P < 0.0001). CONCLUSION: Risk of CIN with CRT implantations was substantial. Increased volume of radiocontrast used for LV lead placement was associated with substantially increased risk of CIN. Minimal contrast use was associated with decreased procedural times without adverse impact on adequacy of lead placement.

Left ventricular lead position for cardiac resynchronization: a comprehensive cinegraphic, echocardiographic, clinical, and survival analysis.

AIMS: We sought to determine the clinical and survival outcomes of cardiac resynchronization therapy (CRT) associated with left ventricular (LV) lead location. The lateral left ventricle has been considered the optimal LV lead location for CRT. METHODS AND RESULTS: Left ventricular lead cinegrams taken in 30° right and left anterior oblique views were evaluated in 457 recipients of CRT with a pacemaker or a defibrillator from 1 January 2002 to 31 December 2008 in this retrospective study. Left ventricular lead placement was prioritized at implantation into posterolateral (PL), anterolateral (AL), middle cardiac, and anterointerventricular coronary veins. Using echocardiographic LV 16-segment analysis, we grouped the leads as anterior, AL, PL, and posterior locations. New York Heart Association (NYHA) class and echocardiography were assessed before and after CRT. Clinical and survival outcomes after CRT were compared among the four LV lead locations.  Patient baseline demographic characteristics were similar among these four groups. Improvement in NYHA class was significantly greater in the AL (P= 0.04) and PL (P= 0.03) locations than in the anterior location. There was a tendency for greater improvement in LV ejection fraction among the AL (P= 0.11) and PL (P= 0.08) locations than the anterior location. Kaplan-Meier survival estimate at 4 years varied for location: AL, 72%; anterior, 48%; PL, 62%; and posterior, 72% (P= 0.003). CONCLUSION: Cardiac resynchronization therapy recipients are profiting from all lead positions. However, LV lead placed in the AL and PL positions is more preferential for achieving optimal CRT benefit than leads placed in the anterior position.

The use of advance directives among patients with implantable cardioverter defibrillators.

BACKGROUND: We aimed to determine the prevalence of advance directives (ADs) among patients with implantable cardioverter defibrillators (ICDs) and of ADs that addressed ICD management at the end of life. METHODS: The medical records of all patients who underwent ICD implantation during 2007 at a single institution were reviewed retrospectively to determine the number of patients with an AD and the number of ADs mentioning the ICD specifically (i.e. ICD management at end of life). RESULTS: During 2007, 420 patients (males, 71%) underwent ICD implantation at our institution (mean age [range] at implantation, 63 [1-90] years). Primary prevention was the most common indication for device therapy (254 patients [61%]). Overall, 127 patients (30%) had an AD, with 83 ADs (65%) completed more than 12 months before ICD implantation and 10 (8%) completed after it. Several life-sustaining treatments were mentioned in the ADs: tube feeding, 46 (37%); cardiopulmonary resuscitation, 25 (20%); mechanical ventilation, 22 (17%); and hemodialysis, nine (7%). Pain control was mentioned in 58 ADs (46%) and comfort measures in 38 (30%). However, only two ADs (2%) mentioned the ICD or its deactivation at end of life. CONCLUSIONS: About one-third of patients with ICDs had an AD, but only a couple ADs mentioned the ICD. These results suggest that clinicians should not only encourage patients with ICDs to complete an AD, but also encourage them to address ICD management specifically. Not addressing ICD management in an AD may result in ethical dilemmas during end-of-life care.

Method of pacing does not affect the recurrence of syncope in carotid sinus syndrome.

INTRODUCTION: Pacemaker therapy is effective in reducing recurrent syncope in patients with symptomatic carotid sinus hypersensitivity (CSH), yet the optimal pacing modality for this syndrome is not known. The objective of this study is to prospectively investigate the impact of three pacing methods (DDDR vs DDDR with sudden bradycardia response [SBR] vs VVI) on recurrent syncope and quality of life. METHODS: Twenty-one patients with symptomatic CSH (syncope or near syncope) were randomized to VVI, DDDR, or DDDR with SBR on a double-blinded basis in a sequential crossover fashion with 6 months in each mode. The primary endpoints were recurrent events and quality of life (assessed by SF-36). The mean number of events and SF-36 scores were compared. RESULTS: At baseline, over the preceding 6 months, there were a total of 29 syncopal events and 258 presyncopal events among 21 patients. Following pacing in any mode, the total number of these syncopal events reduced to two in two patients (P < 0.001) and 17 presyncopal events (P < 0.001) in 12 patients. The mean number of events was not significantly different between the three pacing methods. SF-36 scores revealed some minor benefits of DDDR pacing versus baseline in the categories, but no pacing method was found to be superior. CONCLUSIONS: The study was unable to confirm the initial study hypothesis of a superiority of one pacing modality over another. Quality of life measures allude to potential benefit from DDDR pacing alone.

ISHNE/EHRA expert consensus on remote monitoring of cardiovascular implantable electronic devices (CIEDs).

We are in the midst of a rapidly evolving era of technology-assisted medicine. The field of telemedicine provides the opportunity for highly individualized medical management in a way that has never been possible before. Evolving medical technologies using cardiac implantable devices with capabilities for remote monitoring permit evaluation of multiple parameters of cardiovascular physiology and risk, including cardiac rhythm, device function, blood pressure values, the presence of myocardial ischaemia, and the degree of compensation of congestive heart failure. Cardiac risk, device status, and response to therapies can now be assessed with these electronic systems of detection and reporting. This document reflects the extensive experience from investigators and innovators around the world who are shaping the evolution of this rapidly expanding field, focusing in particular on implantable pacemakers, implantable cardioverter defibrillators, devices for cardiac resynchronization therapy (both with and without defibrillation properties), loop recorders, and hemodynamic monitoring devices. This document covers the basic methodologies, guidelines for their use, experience with existing applications, and the legal and reimbursement aspects associated with their use. To adequately cover this important emerging topic, the International Society for Holter and Noninvasive Electrocardiology and the European Heart Rhythm Association combined their expertise in this field. We hope that the development of this field can contribute to improve care of our cardiovascular patients.

Renal function and mortality following cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) improves outcomes in heart failure, yet selection of patients likely to have survival benefit is problematic. Chronic kidney disease (CKD) is an important determinant of mortality in patients with congestive heart failure therefore we sought to determine the impact of CKD on mortality benefit after CRT. METHODS AND RESULTS: All CRT device implantations in patients not on dialysis at Mayo Clinic between January 1999 and December 2005 were included. Of 482 patients, 342 (71%) had CKD (defined as a glomerular filtration rate (GFR) of ≤60 mL/min/1.73 m(2)) at the time of device implantation. Patients with CKD were older (71 ± 10 vs. 63 ± 14 years, P < 0.01) than patients without CKD, and more often anaemic (12.70 ± 1.73 vs. 13.24 mg/L, P < 0.01), with similar ejection fraction (22 ± 8 vs. 23 ± 8%, P = 0.32). Survival was superior in patients with normal or mild renal dysfunction compared with patients with CKD (72 vs. 57% at 3 years, P < 0.01). After multivariate analysis, CKD remained a significant predictor of poor survival following CRT. CONCLUSION: Chronic kidney disease is common in patients undergoing CRT and associated with a higher mortality and should be considered when evaluating patients for CRT.

Effect of long-term right ventricular pacing in young adults with structurally normal heart.

BACKGROUND: Right ventricular pacing increases the risk of heart failure in adults with structural heart disease. The impact of prolonged right ventricular pacing in adults without structural heart disease is not fully characterized and may depend on interactions of pacing with abnormal substrate predisposing to ventricular dysfunction. METHODS AND RESULTS: We assessed the effect of right ventricular pacing in patients who underwent pacemaker implantation for isolated congenital atrioventricular block between 1964 and 2005. To assess for immunologic contribution to cardiac dysfunction, outcomes were compared between patients with (Ab(+)) and without (Ab(-)) antinuclear antibody during adulthood and an age- and sex-matched Olmsted County, Minnesota, population. Of 103 patients (mean+/-SD age, 32+/-19 years), 18 were Ab(+). Long-term survival free of new heart failure after pacemaker implantation in isolated congenital atrioventricular block patients was worse than in the matched population (P<0.001). This difference was attributable to the development of heart failure in 12 Ab(+) patients (67%; P<0.001), without differences between Ab(-) patients (2%) and the matched population (2%; P=0.7). Compared with baseline, at last follow-up, left ventricular ejection fraction did not decline in Ab(-) (53+/-9% to 57+/-12%) but decreased in Ab(+)(52+/-10% to 38+/-12%; P=0.03) patients. Survival was similar in Ab(-) patients and the Minnesota population (98%; P=0.7) but worse in Ab(+) patients (79%; P<0.01). CONCLUSIONS: The natural history of patients with isolated congenital atrioventricular block who require pacing depends upon their antibody status. Antinuclear antibody status was a predictor for the development of heart failure and death. Long-term right ventricular pacing alone does not appear to be associated with development of heart failure, deterioration in ventricular function, or reduced survival in Ab(-) isolated congenital atrioventricular block patients.