Abstract 17444: Strategic Use of Magnetic Resonance Imaging in Arrhythmic Risk Stratification of Asymptomatic Arrhythmogenic Right Ventricular Cardiomyopathy Mutation Carriers

Abstract

Introduction: Because of the clinically heterogeneous nature of the disease, risk stratification of asymptomatic Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) associated mutation carriers is challenging. We sought to identify the optimal role of Magnetic Resonance Imaging (MRI) in the prognostic work-up of these patients.

Methods: We included 66 patients (age 27.0 ± 15.3 years, 44% male) harboring ARVC associated mutations (80% PKP-2) without prior sustained VT or VF. ECG, Holter, and signal-averaged ECG at presentation were analyzed for electrical abnormalities as per revised Task Force criteria. MRI studies were done to identify abnormal cardiac structure and/or function (defined as global and/or regional dilatation, wall motion abnormalities, fat and/or delayed enhancement).

Results: Overall, 47 (71%) patients presented with electrical abnormalities, of whom 26 (55%) had concomitant MRI abnormalities. Over a mean follow-up of 5.9 ± 4.5 years, 10 (15%) patients experienced sustained ventricular arrhythmias. None of the 19 (29%) patients without electrical abnormalities at presentation experienced an arrhythmic event during 6.6 ± 4.4 years of follow-up (negative predictive value 100%), despite abnormal MRI in 3 (16%) of them. Among patients with baseline electrical abnormalities (n=47, 71%), arrhythmic events occurred only in patients with abnormal MRI (10/26 patients, positive predictive value 38%) during 5.6 ± 4.5 years of follow-up (Figure).

Conclusion: Asymptomatic ARVC mutation carriers without electrical abnormalities have no arrhythmic events during long-term follow up irrespective of MRI findings. These data suggest that, in the absence of electrical abnormalities, MRI abnormalities may lack prognostic information. The presence of both electrical and MRI abnormalities identifies patients at high risk of events and thus patients who might benefit from prophylactic implantable cardioverter-defibrillator implantation.