Abstract 13015: First-degree Atrioventricular Block is Associated With Incident Atrial Fibrillation in the Japanese General Population Aged ≥ 40 Years

Abstract

Introduction: First-degree atrioventricular block (fAVB) is a common cardiac conduction disorder diagnosed by prolongation of the PR interval ≥220 msec. Although it is generally considered benign, some previous studies demonstrated that fAVB was associated with incident atrial fibrillation (AF). However, evidence is scarce regarding the association between fAVB and incident AF in older populations. Hypothesis: We hypothesized that fAVB was significantly associated with incident AF in older populations. Methods: Eligible participants were residents in Kanazawa City who aged ≥ 40 years and underwent 12-lead ECG at the national Japanese health checkups in 2013. Participants with AF detected at the baseline exam and with no follow-up examinations between 2014 and 2018. fAVB was defined as PR interval ≥ 220 msec based on the Minnesota code (6-3). Incident AF was defined as the first episode of AF detected by 12-lead ECG at the annual health checkups. The cumulative incidence of AF was estimated by the Kaplan Meier curve analysis, and statistical significance was evaluated by the log-rank test. Unadjusted and adjusted hazard ratios (HRs) were computed by the Cox proportional hazard model. HRs were adjusted using three models in which conventional risk factors for AF were included (Table). Results: 37,730 participants (mean age, 72.3 ± 9.6 years; Male, 37%) were included. Baseline fAVB was observed in 667 (1.8%) participants. During the median follow-up period of 5 years (interquartile range, 4.0 - 5.0 years), 691 cases of incident AF were observed. Kaplan Meier curve showed that a 5-year cumulative incidence of AF was significantly higher in fAVB (+) group compared with fAVB (-) group (6.8% vs 2.1%, p < 0.01). In the fully adjusted model, fAVB was significantly associated with incident AF (HR, 1.75; 95% confidence interval, 1.25 - 2.45; p-value < 0.01) (Table). Conclusion: fAVB was independently associated with incident AF in this predominantly elderly Japanese population.