Disease Progression in Exercise-Induced Arrhythmogenic Cardiomyopathy Compared With Arrhythmogenic Right Ventricular Cardiomyopathy.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inheritable heart disease, whereas exercise-induced arrhythmogenic cardiomyopathy (EiAC) is a proposed acquired similar phenotype in athletes. The differences in disease progression between these entities are not well understood.

Objectives: This study aims to assess structural, functional, and arrhythmic disease progression in EiAC compared with ARVC.

Methods: This longitudinal cohort study included EiAC patients who were competitive endurance athletes (>24 MET-hours/week for >6 consecutive years) referred due to ventricular arrhythmias (VA), without inherited or genetic factors or other evident causes, and genotype-positive ARVC patients with a definite diagnosis and their genotype-positive family members for comparison. Disease progression was assessed by repeated echocardiographic examinations and incident VA during long-term follow-up.

Results: The authors included 125 ARVC patients (61 women, aged 38 ± 17 years) and 41 EiAC patients (6 women, aged 45 ± 13 years) and followed them for 96 months (Q1-Q3: 73-132 months) and 82 months (Q1-Q3: 50-118 months), respectively. The authors analyzed 730 echocardiographic examinations (538 ARVC, 192 EiAC). Right ventricular (RV) structure and function remained stable in EiAC patients, whereas those in ARVC patients deteriorated during follow-up. The 5-year and 10-year cumulative incidences of VA were similar between EiAC and ARVC patients.

Conclusions: RV structure and function deteriorated in ARVC patients but remained stable in EiAC patients during follow-up. The incidence of VA was high in both populations. These results indicate that EiAC patients should be followed closely over time regardless of structural and functional progression.