Exercise exposure and arrhythmic patterns in arrhythmogenic right ventricular cardiomyopathy

BACKGROUND: Exercise is associated with ventricular arrhythmias (VA) in arrhythmogenic right ventricular cardiomyopathy (ARVC), but relationships with atrial fibrillation (AF) and arrhythmic patterns are less established. OBJECTIVE: To assess prior exercise intensity and dose in relation to AF, VA, and combined arrhythmic patterns across the ARVC diagnostic spectrum. METHODS: Genotype-positive probands and relatives were included. Exercise during the three years preceding diagnosis was assessed retrospectively by structured interview. Intensity was defined by the primary activity's Metabolic Equivalent of Task (MET) and dose as MET-hours/week across activities. AF and VA were assessed at first visit and last follow-up. RESULTS: We included 122 individuals (49% women; mean age 39±17 years), with a median follow-up of 13.5 years. AF prevalence increased from 5% to 21% and VA from 26% to 37%. Median onset ages were 55 years for AF and 36 years for VA. Both exercise measures were associated with VA at both time points. Exercise dose was associated with AF at first visit and intensity at last follow-up. Median exercise dose increased across groups with no arrhythmia, AF only, VA only, and both. The association between AF and VA at last follow-up was attenuated after adjustment for exercise intensity (adjusted OR 2.43, 95% CI 0.85-6.97, p=0.10). CONCLUSIONS: Associations with exercise was consistently associated with VA, but varied for AF by measure and time point. The graded distribution does not establish thresholds or sequential progression. Co-occurrence may reflect shared exercise history, disease susceptibility, and differential surveillance rather than a direct relationship.