Cardiac sarcoidosis
B. Cardiac positron emission tomography
Several ECG features suggest a diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC) in this case. There is a notable low-amplitude, positive deflection between the end of the QRS complex and the onset of the T wave, most prominent in the right precordial leads (V2 and V3), consistent with an epsilon wave. Other findings include both premature ventricular contractions (PVCs) and nonsustained ventricular tachycardia with a left bundle branch block (LBBB) morphology and an inferior axis. T-wave inversions are seen in leads V1-V4, though notably in the presence of a complete right bundle branch block (cRBBB). The patient met diagnostic criteria for ARVC based on electrophysiological data alone: 1 major criterion, ie, presence of epsilon waves on the ECGs, and 3 minor criteria including T-wave inversions in V1-V4 in the presence of cRBBB, frequent PVCs (>500 per 24 hours on telemetry), as well as nonsustained ventricular tachycardia with an LBBB morphology.1 The diagnosis of ARVC was further supported by major imaging criteria as cardiac magnetic resonance imaging revealed RV regional akinesis and dyskinesis, RV end diastolic volume more than 110 mL/m2, and a moderately decreased systolic function with ejection fraction of 40% or less.1 Notably, there was also significant LV involvement with late gadolinium enhancement composing 38% of total LV myocardial mass. However, this finding does not necessarily raise doubt with respect to a diagnosis of ARVC, as concomitant involvement of the left ventricle is a well-documented feature of advanced ARVC, with 1 study documenting LV involvement in 76% of hearts with autopsy-proven ARVC.2