Mega-epsilon waves on 12-lead ECG--just another case of arrhythmogenic right ventricular dysplasia/cardiomyopathy?

Epsilon wave, the post-excitation small squiggles at the beginning of ST segment that first named by Fontaine, is a well-known ECG phenomenon frequently associated with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Epsilon waves are caused by post excitation of the myocytes in the right ventricle due to myocardial scaring. Increasing evidence suggests that cardiac sarcoidosis might produce the pathological substrate required for production of epsilon waves. Therefore differentiating these two entities is of paramount clinical importance. Here we report a case demonstrating mega-epsilon wave, right ventricular dilatation and inducible ventricular tachycardia (VT) that was initially diagnosed as ARVD/C by the Task Force Criteria. However after a thorough evaluation, diagnosis of cardiac sarcoidosis was confirmed by the evidence of non-caseating granulomas from endomycardial biopsy.