Contemporary procedure characteristics and outcomes of accessory atrioventricular pathway ablations in an integrated community-based health care system using a tiered approach.

BACKGROUND: Since the early descriptions of large series of accessory atrioventricular pathway ablations in adults and adolescents over 20 years ago, there have been limited published reports based on more recent experiences of large referral centers. We aimed to characterize accessory pathway distribution and features in a large community-based population that influence ablation outcomes using a tiered approach to ablation. METHODS: Retrospective analysis of 289 patients (age 14-81) who underwent accessory ablation from 2015-2019 was performed. Pathways were categorized into anteroseptal, left freewall, posteroseptal, and right freewall locations. We analyzed patient and pathway features to identify factors associated with prolonged procedure time parameters. RESULTS: Initial ablation success rate was 94.7% with long-term success rate of 93.4% and median follow-up of 931 days. Accessory pathways were in left freewall (61.6%), posteroseptal (24.6%), right freewall (9.6%), and anteroseptal (4.3%) locations. Procedure outcome was dependent on pathway location. Acute success was highest for left freewall pathways (97.1%) with lowest case times (144 ± 68 min) and fluoroscopy times (15 ± 19 min). Longest procedure time parameters were seen with anteroseptal, left anterolateral, epicardial-coronary sinus, and right anterolateral pathway ablations. CONCLUSIONS: In this community-based adult and adolescent population, majority of the accessory pathways are in the left freewall and posteroseptal region and tend to be more easily ablated. A tiered approach with initial use of standard ablation equipment before the deployment of more advance tools, such as irrigated tips and 3D mapping, is cost effective without sacrificing overall efficacy.

The association of multimorbidity to mortality in older adults after permanent pacemaker placement.

BACKGROUND: In the United States 2018 bradycardia guideline, the current class III recommendation that patients with permanent pacemaker (PPM) indications and high multimorbidity burden may not have meaningful clinical benefit from PPM therapy is based on limited data. METHODS: Observational study (January 1, 2008-December 31, 2015) of adults ≥65 years (N = 16,678) who underwent PPM implantation. Exposure variable: Elixhauser comorbidity number (ECN, 29 well-validated conditions). PRIMARY OUTCOME: ≤1-year mortality; secondary outcome: > 1-year mortality. RESULTS: Those who died ≤1-year were older, had a lower body mass index (BMI), and higher ECN (p < .001). Cumulative survival at 1-year was 92.3% (95% confidence interval [CI]: 91.9-92.7). One-year survival decreased by increasing ECN-with a difference at 1-year between lowest and highest ECN category of 17.3% (ECN 0-1: 97.1% [95% CI: 96.3-97.7]; ECN ≥8: 79.8% [95% CI: 77.9-81.5]). For those who survived the first year, cumulative survival at 8-years was 51.2% (95% CI = 49.8-52.6) with a difference between ECN 0-1 and ≥8 of 43.4%. Increasing ECN was associated equally with ≤1-year (HR 1.28 [95% CI: 1.25-1.30]) and >1-year (HR 1.19 [95% CI: 1.17-1.20]) mortality. A predictive model including age, sex, BMI, PPM type, race, and ECN had greater discriminative ability (p < .0001) than a bedside model (age, sex) for the primary outcome. CONCLUSION: Across the heterogeneity of indications for PPM placement, multimorbidity is increasingly common. The association of multimorbidity to mortality (≤1-year, >1-year) should be routinely discussed during the shared decision-making process as an important prognostic geriatric domain variable.

Comparison of Long-Term Adverse Outcomes in Patients With Atrial Fibrillation Having Ablation Versus Antiarrhythmic Medications.

The impact of atrial fibrillation (AF) catheter ablation versus chronic antiarrhythmic therapy alone on clinical outcomes such as death and stroke remains unclear. We compared adverse outcomes for AF ablation versus chronic antiarrhythmic therapy in 1,070 adults with AF treated between 2010 and 2014 in the Kaiser Permanente Northern California and Southern California healthcare delivery systems. Patients who underwent AF catheter ablation were matched to patients treated with only antiarrhythmic medications, based on age, gender, history of heart failure, history of coronary heart disease, history of hypertension, history of diabetes, and high-dimensional propensity score. We compared crude and adjusted rates of death, ischemic stroke or transient ischemic attack, intracranial hemorrhage, and hospitalization. The matched cohort of 535 patients treated with AF ablation and 535 treated with antiarrhythmic therapy had a median follow-up of 2.0 (interquartile range 1.1 to 3.5) years. There was no significant difference in adjusted rates of death (adjusted hazard ratio [HR] 0.24, 95% confidence interval [CI] 0.03 to 1.95), intracranial hemorrhage (adjusted HR 0.17, CI 0.02 to 1.71), ischemic stroke or transient ischemic attack (adjusted HR 0.53, CI 0.18 to 1.60), and heart failure hospitalization (adjusted HR 0.85, CI 0.34 to 2.12), although there was a trend toward improvement in these outcomes with ablation. However, there was a significantly increased risk of all-cause hospitalization following ablation (adjusted HR 1.60, CI 1.25 to 2.05). In a contemporary, multicenter, propensity-matched observational cohort, AF ablation was not significantly associated with death, intracranial hemorrhage, ischemic stroke or transient ischemic attack, or heart failure hospitalization, but was associated with a higher rate of all cause-hospitalization.

Influence of Multimorbidity on Burden and Appropriateness of Implantable Cardioverter-Defibrillator Therapies.

OBJECTIVE: To determine whether burden of multiple chronic conditions (MCCs) influences the risk of receiving inappropriate vs appropriate device therapies. DESIGN: Retrospective cohort study. SETTING: Seven US healthcare delivery systems. PARTICIPANTS: Adults with left ventricular systolic dysfunction receiving an implantable cardioverter-defibrillator (ICD) for primary prevention. MEASUREMENTS: Data on 24 comorbid conditions were captured from electronic health records and categorized into quartiles of comorbidity burden (0-3, 4-5, 6-7 and 8-16). Incidence of ICD therapies (shock and antitachycardia pacing [ATP] therapies), including appropriateness, was collected for 3 years after implantation. Outcomes included time to first ICD therapy, total ICD therapy burden, and risk of inappropriate vs appropriate ICD therapy. RESULTS: Among 2235 patients (mean age = 69 ± 11 years, 75% men), the median number of comorbidities was 6 (interquartile range = 4-8), with 98% having at least two comorbidities. During a mean 2.2 years of follow-up, 18.3% of patients experienced at least one appropriate therapy and 9.9% experienced at least one inappropriate therapy. Higher comorbidity burden was associated with an increased risk of first inappropriate therapy (adjusted hazard ratio [HR] = 1.94 [95% confidence interval {CI} = 1.14-3.31] for 4-5 comorbidities; HR = 2.25 [95% CI = 1.25-4.05] for 6-7 comorbidities; and HR = 2.91 [95% CI = 1.54-5.50] for 8-16 comorbidities). Participants with 8-16 comorbidities had a higher total burden of ICD therapy (adjusted relative risk [RR] = 2.12 [95% CI = 1.43-3.16]), a higher burden of inappropriate therapy (RR = 3.39 [95% CI = 1.67-6.86]), and a higher risk of receiving inappropriate vs appropriate therapy (RR = 1.74 [95% CI = 1.07-2.82]). Comorbidity burden was not significantly associated with receipt of appropriate ICD therapies. Patterns were similar when separately examining shock or ATP therapies. CONCLUSIONS: In primary prevention ICD recipients, MCC burden was independently associated with an increased risk of inappropriate but not appropriate device therapies. Comorbidity burden should be considered when engaging patients in shared decision making about ICD implantation.

Contemporary Burden and Correlates of Symptomatic Paroxysmal Supraventricular Tachycardia.

BACKGROUND: Contemporary data about symptomatic paroxysmal supraventricular tachycardia (PSVT) epidemiology are limited. We characterized prevalence and correlates of symptomatic PSVT within a large healthcare delivery system and estimated national PSVT burden. METHODS AND RESULTS: We identified adults with an encounter for potential PSVT between 2010 and 2015 in Kaiser Permanente Northern California, excluding those with prior known atrial fibrillation or atrial flutter. We adjudicated medical records, ECGs, and other monitoring data to estimate positive predictive values for targeted International Classification of Diseases (ICD), 9th and 10th Revisions codes in inpatient, emergency department, and outpatient settings. Combinations of diagnosis codes and settings were used to calculate PSVT prevalence, and PSVT correlates were identified using multivariable regression. We estimated national rates by applying prevalence estimates in Kaiser Permanente to 2010 US Census data. The highest positive predictive values included codes for "PSVT" in the emergency department (82%), "unspecified cardiac dysrhythmia" in the emergency department (27%), "anomalous atrioventricular excitation" as a primary inpatient diagnosis (33%), and "unspecified paroxysmal tachycardia" as a primary inpatient diagnosis (23%). Prevalence of symptomatic PSVT was 140 per 100 000 (95% confidence interval, 100-179) and was higher for individuals who were older, women, white or black, or who had valvular heart disease, heart failure, diabetes mellitus, lung disease, or prior bleeding. We estimate the national prevalence of symptomatic PSVT to be 168 per 100 000 (95% confidence interval, 120-215). CONCLUSIONS: Selected diagnostic codes in inpatient and emergency department settings may be useful to identify symptomatic PSVT episodes. We project that at least 0.168% of US adults experience symptomatic PSVT, and certain characteristics can identify people at higher risk.

Association of Burden of Atrial Fibrillation With Risk of Ischemic Stroke in Adults With Paroxysmal Atrial Fibrillation: The KP-RHYTHM Study.

Importance: Atrial fibrillation is a potent risk factor for stroke, but whether the burden of atrial fibrillation in patients with paroxysmal atrial fibrillation independently influences the risk of thromboembolism remains controversial. Objective: To determine if the burden of atrial fibrillation characterized using noninvasive, continuous ambulatory monitoring is associated with the risk of ischemic stroke or arterial thromboembolism in adults with paroxysmal atrial fibrillation. Design, Setting, and Participants: This retrospective cohort study conducted from October 2011 and October 2016 at 2 large integrated health care delivery systems used an extended continuous cardiac monitoring system to identify adults who were found to have paroxysmal atrial fibrillation on 14-day continuous ambulatory electrocardiographic monitoring. Exposures: The burden of atrial fibrillation was defined as the percentage of analyzable wear time in atrial fibrillation or flutter during the up to 14-day monitoring period. Main Outcomes and Measures: Ischemic stroke and other arterial thromboembolic events occurring while patients were not taking anticoagulation were identified through November 2016 using electronic medical records and were validated by manual review. We evaluated the association of the burden of atrial fibrillation with thromboembolism while not taking anticoagulation after adjusting for the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) or CHA2DS2-VASc stroke risk scores. Results: Among 1965 adults with paroxysmal atrial fibrillation, the mean (SD) age was 69 (11.8) years, 880 (45%) were women, 496 (25%) were persons of color, the median ATRIA stroke risk score was 4 (interquartile range [IQR], 2-7), and the median CHA2DS2-VASc score was 3 (IQR, 1-4). The median burden of atrial fibrillation was 4.4% (IQR ,1.1%-17.23%). Patients with a higher burden of atrial fibrillation were less likely to be women or of Hispanic ethnicity, but had more prior cardioversion attempts compared with those who had a lower burden. After adjusting for either ATRIA or CHA2DS2-VASc stroke risk scores, the highest tertile of atrial fibrillation burden (≥11.4%) was associated with a more than 3-fold higher adjusted rate of thromboembolism while not taking anticoagulants (adjusted hazard ratios, 3.13 [95% CI, 1.50-6.56] and 3.16 [95% CI, 1.51-6.62], respectively) compared with the combined lower 2 tertiles of atrial fibrillation burden. Results were consistent across demographic and clinical subgroups. Conclusions and Relevance: A greater burden of atrial fibrillation is associated with a higher risk of ischemic stroke independent of known stroke risk factors in adults with paroxysmal atrial fibrillation.

Contemporary Procedural Complications, Hospitalizations, and Emergency Visits After Catheter Ablation for Atrial Fibrillation.

Contemporary data on complications and resource utilization after atrial fibrillation (AF) ablation are limited. We evaluated rates and risk factors for procedural complication, rehospitalization, and emergency department visits after AF ablation. We identified all adult patients who underwent isolated AF ablation between 2010 and June 2014 in 2 large integrated health-care delivery systems and evaluated rates of acute inpatient complication, 30-day, and 1-year readmission and emergency evaluation. We used multivariable logistic regression to identify predictors of procedural complications, 30-day readmission, or 30-day emergency department evaluation. In 811 AF ablation patients, procedural complications occurred in 2.5% of patients, 9.7% of patients were rehospitalized within 30 days, and 19.1% of patients had an emergency visit within 30 days. At 1 year after AF ablation, 28.9% of patients were readmitted, with 18% of patients readmitted for AF or atrial flutter. At 1 year, 44.5% of patients were seen in an emergency department, with 37.1% related to AF or atrial flutter. Vascular complications and perforation or tamponade were the most common complications, and Hispanic ethnicity, mitral or aortic valvular disease, and diabetes mellitus were the strongest risk factors for adverse outcomes at 30 days after AF ablation. Contemporary rates of acute complication and 1-year readmission after AF ablation have markedly decreased compared with previous community-based studies.

Effect of Advancing Age and Multiple Chronic Conditions on Mortality in Patients with End-Stage Renal Disease after Implantable Cardioverter-Defibrillator Placement.

CONTEXT: There is insufficient information on the effect that advancing age and multiple chronic conditions (MCC) have on mortality after placement of an implantable cardioverter-defibrillator in patients with end-stage renal disease (ESRD) vs non-ESRD. OBJECTIVE: To assess whether a differential effect of age and MCC exists between ESRD and non-ESRD. DESIGN: Population-based, retrospective cohort study using data from the national Kaiser Permanente Cardiac Device Registry of patients who underwent placement of an implantable cardioverter-defibrillator between January 1, 2007, and December 31, 2013. MAIN OUTCOME MEASURES: All-cause mortality. RESULTS: Of 7825 patients with implantable cardioverter-defibrillator placement, ESRD-affected patients constituted 4.0% of the cohort (n = 311), were similar in age (p = 0.91), and presented with a larger comorbidity burden (3.3 ± 1.3 vs 2.4 ± 1.5, p < 0.001). The effect of advancing age (every 5 years) on mortality in the ESRD cohort (hazard ratio [HR] = 1.11, 95% confidence interval [CI] = 1.03-1.20) was less than in the non-ESRD cohort (HR = 1.28, 95% CI = 1.25-1.32). Similarly, the effect of each additional comorbidity in the ESRD cohort was less (HR = 1.04, 95% CI = 0.91-1.19) than in the non-ESRD group (HR = 1.20, 95% CI = 1.16-1.25). Lastly, ESRD was independently associated with a 3-fold greater hazard of mortality. CONCLUSIONS: Advancing age and increasing number of MCC have a differential effect on mortality risk in patients with ESRD compared with their non-ESRD counterparts. Future studies should focus on assessment of nonlinear relationships of age, MCC, and naturally occurring clusters of MCC on mortality.

Age and sex differences in long-term outcomes following implantable cardioverter-defibrillator placement in contemporary clinical practice: findings from the Cardiovascular Research Network.

BACKGROUND: Patient sex and age may influence rates of death after receiving an implantable cardioverter-defibrillator for primary prevention. Differences in outcomes other than mortality and whether these differences vary by heart failure symptoms, etiology, and left ventricular ejection fraction are not well characterized. METHODS AND RESULTS: We studied 2954 patients with left ventricular ejection fraction ≤0.35 undergoing first-time implantable cardioverter-defibrillator for primary prevention within the Cardiovascular Research Network; 769 patients (26%) were women, and 2827 (62%) were aged >65 years. In a median follow-up of 2.4 years, outcome rates per 1000 patient-years were 109 for death, 438 for hospitalization, and 111 for heart failure hospitalizations. Procedure-related complications occurred in 8.36%. In multivariable models, women had significantly lower risks of death (hazard ratio 0.67, 95% CI 0.56 to 0.80) and heart failure hospitalization (hazard ratio 0.82, 95% CI 0.68 to 0.98) and higher risks for complications (hazard ratio 1.38, 95% CI 1.01 to 1.90) than men; patients aged >65 years had higher risks of death (hazard ratio 1.55, 95% CI 1.30 to 1.86) and heart failure hospitalization (hazard ratio 1.25, 95% CI 1.05 to 1.49) than younger patients. Age and sex differences were generally consistent in strata according to symptoms, etiology, and severity of left ventricular systolic dysfunction, except the higher risk of complications in women, which differed by New York Heart Association classification (P=0.03 for sex-New York Heart Association interaction), and the risk of heart failure hospitalization in older patients, which differed by etiology of heart failure (P=0.05 for age-etiology interaction). CONCLUSIONS: The burden of adverse outcomes after receipt of an implantable cardioverter-defibrillator for primary prevention is substantial and varies according to patient age and sex. These differences in outcome generally do not vary according to baseline heart failure characteristics.

Coxsackievirus and adenovirus receptor (CAR) mediates atrioventricular-node function and connexin 45 localization in the murine heart.

The coxsackievirus and adenovirus receptor (CAR) is a transmembrane protein that belongs to the family of adhesion molecules. In the postnatal heart, it is localized predominantly at the intercalated disc, where its function is not known. Here, we demonstrate that a first degree or complete block of atrioventricular (AV) conduction developed in the absence of CAR in the adult mouse heart and that prolongation of AV conduction occurred in the embryonic heart of the global CAR-KO mouse. In the cardiac-specific CAR-KO (CAR-cKO) mouse, we observed the loss of connexin 45 localization to the cell-cell junctions of the AV node but preservation of connexin 40 and 43 in contracting myocardial cells and connexin 30.2 in the AV node. There was also a marked decrease in beta-catenin and zonula occludens-1 (ZO-1) localization to the intercalated discs of CAR-cKO mouse hearts at 8 weeks before the mice developed cardiomyopathy at 21 weeks of age. We also found that CAR formed a complex with connexin 45 via its PSD-95/DigA/ZO-1-binding (PDZ-binding) motifs. We conclude that CAR expression is required for normal AV-node conduction and cardiac function. Furthermore, localization of connexin 45 at the AV-node cell-cell junction and of beta-catenin and ZO-1 at the ventricular intercalated disc are dependent on CAR.