As opposed to ventricular arrhythmias (VA), clinical implications of atrial tachyarrhythmias (AT) in arrhythmogenic right ventricular cardiomyopathy (ARVC) remain scarcely explored. This study sought to evaluate the prevalence and prognostic significance of AT in ARVC.

In total, 171 patients diagnosed with ARVC between 1985 and 2018 in a single tertiary center were retrospectively included. Were defined as follows: AT: sustained atrial fibrillation, atrial flutter and focal atrial tachycardia; major adverse cardiovascular events (MAE) as a composite criterion including heart failure, cardiac assistance, transplantation, and death.

After a median follow-up of 6years (IQR 3 to 11), prevalence of AT, MAE and VA were respectively of 16%, 8% and 60%. AT occurred later in the disease course: mean age 54±14.4, while 50% of patients had VA at diagnosis. Age at diagnosis (hazard-ratio [HR]: 1.05, 95% CI [1.02–1.08]; P<0.001), RVEF (HR: 0.96, 95% CI [0.92–0.99]; P=0.03) and LVEF (HR: 0.96; 95% CI: 0.92–0.99; P=0.04) predicted AT occurrence in univariable analysis. Intensive sport activity was significantly associated with AT in survival and multivariable Cox analysis. AT was predictive of MAE occurrence (HR: 2.6, 95% CI [1.1–6.3]; P=0.03).

AT are common in ARVC and AT is associated with intensive sport activity and MAE. Our results mandate careful monitoring of ARVC patients with new-onset AT.