Clinical Differentiation Between Physiological Remodeling and Arrhythmogenic Right Ventricular Cardiomyopathy in Athletes With Marked Electrocardiographic Repolarization Anomalies

BACKGROUND Physiological cardiac adaptation to regular exercise, including biventricular dilation and T-wave inversion (TWI), may create diagnostic overlap with arrhythmogenic right ventricular cardiomyopathy (ARVC). OBJECTIVES The goal of this study was to assess the accuracy of diagnostic criteria for ARVC when applied to athletes exhibiting electrocardiographic TWI and to identify discriminators between physiology and disease. METHODS The study population consisted of athletes with TWI (n = 45), athletes without TWI (n = 35), and ARVC patients (n = 35). Subjects underwent electrocardiography (ECG), signal-averaged electrocardiography (SAECG), echocardiography, cardiac magnetic resonance imaging (CMRI), Holter monitoring, and exercise testing. RESULTS There were no electrical, structural, or functional cardiac differences between athletes exhibiting TWI and athletes without TWI. When athletes were compared with ARVC patients, markers of physiological remodeling included early repolarization, biphasic TWI, voltage criteria for right ventricular (RV) or left ventricular hypertrophy, and symmetrical cardiac enlargement. Indicators of RV pathology included the following: syncope; Q waves or precordial QRS amplitudes <1.8 mV; 3 abnormal SAECG parameters; delayed gadolinium enhancement, RV ejection fraction <= 45%, or wall motion abnormalities at CMRI; >1,000 ventricular extrasystoles (or >500 non-RV outflow tract) per 24 h; and symptoms, ventricular tachyarrhythmias, or attenuated blood pressure response during exercise. Nonspecific parameters included the following: prolonged QRS terminal activation; <= 2 abnormal SAECG parameters; RV dilation without wall motion abnormalities; RV outflow tract ectopy; and exercise-induced T-wave pseudonormalization. CONCLUSIONS TWI and balanced biventricular dilation are likely to represent benign manifestations of training in asymptomatic athletes without relevant family history. Diagnostic criteria for ARVC are nonspecific in such individuals. Comprehensive testing using widely available techniques can effectively differentiate borderline cases. (C) 2015 by the American College of Cardiology Foundation.