Po-05-139 cardiac sarcoidosis meeting diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy: prevalence, characteristics, and differentiation from hereditary arrhythmogenic right ventricular cardiomyopathy

Cardiac sarcoidosis (CS) can show overlap in the clinical manifestation with arrhythmogenic right ventricular cardiomyopathy (ARVC). To date, there have been no reports unitarily examining its prevalence, characteristics, and differentiation from genetically proven ARVC. This study was conducted for two purposes: (1) To investigate the prevalence and clinical impact of meeting the diagnostic criteria for ARVC in CS patients. (2) To evaluate the discriminator between CS patients meeting ARVC diagnostic criteria and hereditary ARVC patients. In study 1, a total of 169 CS patients diagnosed using the Japanese guideline in 2016 were evaluated. In study 2, we compared the CS patients meeting ARVC diagnostic criteria with 30 ARVC patients with plakophilin-2 or desmoglein-2 variant. Study 1 revealed that 26 patients (15.4%; overlap CS) had a definite diagnosis of ARVC based on the revised Task Force Criteria (Table). Overlap CS patients showed significantly lower both ventricular ejection fraction (EF) and larger right ventricular end-diastolic volume index (RVEDVI) on magnetic resonance imaging (MRI) than other CS patients (non-overlap CS). Overlap CS had 14 out of 26 patients (58.9%) with clinically diagnosed CS, which did not differ from non-overlap CS. Fluorodeoxyglucose-positron emission tomography was positive in all overlap CS patients. In Kaplan-Meier analysis, fatal ventricular tachyarrhythmia, heart failure hospitalization, and death were similar between the two groups. Study 2 revealed that septal thinning with echocardiography was observed in 17 overlap CS patients but no ARVC patients (P < 0.0001). On MRI, overlap CS patients showed a significantly lower left ventricular EF and smaller RVEDVI than ARVC (P < 0.0001 and P = 0.0155, respectively). An algorithm including the presence of septal thinning, PR interval of ≥170 ms, and QRS interval of ≥115 ms had 89% sensitivity and 87% specificity for diagnosing overlap CS (Figure). Patients with CS who meet the diagnostic criteria for ARVC are not uncommon, especially in patients with severely impaired cardiac function despite similar clinical events. An algorithm including septal thinning, PR prolongation, and QRS prolongation can largely differentiate between overlap CS and ARVC.