Arrhythmogenic right ventricular dysplasia/cardiomyopathy and cardiac sarcoidosis: distinguishing features when the diagnosis is unclear.

BACKGROUND Cardiac sarcoidosis (CS) may show overlap in the clinical presentation with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). We sought to investigate patients with CS who were misdiagnosed with ARVD/C and identify clinical features to distinguish these 2 groups. METHODS AND RESULTS Among patients enrolled in the Johns Hopkins ARVD/C registry, 15 patients with definite 2010 diagnostic criteria for ARVD/C were subsequently diagnosed with CS. Forty-two pathogenic desmosomal mutation carriers with definite ARVD/C based on the 2010 diagnostic criteria served as a control group. Patients with CS were older at the age of symptom onset, more likely to have comorbidities, and develop heart failure symptoms over time (P<0.05). Electrocardiographically, PR interval prolongation and high-grade atrioventricular block were exclusively associated with CS (P<0.05). HV interval prolongation and increased number of ventricular tachycardias induced were also associated with CS (P<0.05). Radiographically, significant left ventricular dysfunction, myocardial delayed enhancement of the septum, and mediastinal lymphadenopathy were more often see in those with CS (P<0.05). CONCLUSIONS The 2010 diagnostic criteria for ARVD/C have limited discrimination in distinguishing between ARVD/C and CS. Despite the overlay in clinical presentation, older age of symptom onset, presence of cardiovascular comorbidities, nonfamilial pattern of disease, PR interval prolongation, high-grade atrioventricular block, significant left ventricular dysfunction, myocardial delayed enhancement of the septum, and mediastinal lymphadenopathy should raise the suspicion for CS.