Utility of cardiac magnetic resonance in the evaluation of unselected patients with possible arrhythmogenic right ventricular cardiomyopathy

Abstract

Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare but important cause of sudden cardiac death. We investigated the role of cardiac magnetic resonance imaging (CMR) in the evaluation of patients with suspected ARVC referred by a general cardiology service.

Methods: Ninety-two patients (mean age 48 ± 15, 49% female), referred for CMR assessment of possible ARVC, were reviewed. CMR included both functional and tissue characteristic imaging.

Results: No patients had ARVC based on the 1994 Task Force Criteria (TFC) prior to CMR, but 4 met proposed Modified TFC; 15% met one major (±1 minor) TFC, 71% 1 or 2 minor TFC, and 14% no TFC. Reasons for CMR referral included symptomatic arrhythmia of likely RV origin (28%), Electrocardiogram/Holter abnormalities (28%), echocardiographic features suspicious of ARVC (19%), and family history of ARVC (8%). CMR findings strongly suggestive of ARVC were found in nine patients (10%), although only three were considered typical. Of these patients two met 1 major TFC and seven met 1 or 2 minor TFC. CMR findings included RV thinning, aneurysm, and diastolic out-pouching, but only 1 patient had definite fatty infiltration of the RV. Incidentally, CMR detected important, previously undiagnosed pathology, including anomalous pulmonary venous drainage (2 patients) and non-ischaemic cardiomyopathy (6%). CMR was normal in 63%, with minor abnormalities in 29%.

Conclusions: CMR may play an important diagnostic role in the evaluation of possible ARVC. Patients who do not meet TFC for diagnosis may have CMR features typical of ARVC. Additionally CMR may detect other hitherto undiagnosed structural or functional abnormalities that alter patient management. However the majority of patients referred have a low pretest probability of ARVC, and the rate of normal CMR scans is high.

Keywords: cardiac magnetic resonance imaging; cardiomyopathy.

Figure 1

CMR 4 Chamber images, at end diastole (A) and end systole (B), using cine imaging. Note the focal akinesis of the basal segment of the RV free wall (arrows). The corresponding T1 turbo spin echo sequence is shown in (C) demonstrating fatty infiltration in the same segments (arrows). Note: Although not diagnostic, based on CMR findings this patient was considered highly likely to have ARVC.

Figure 2

CMR cine image showing anomalous pulmonary venous drainage to the right atrium, an incidental finding in a patient referred for possible ARVC based on RV enlargement on echocardiography.