Right ventricular arrhythmia in the absence of arrhythmogenic dysplasia: MR imaging of myocardial abnormalities

To evaluate right ventricular abnormalities with magnetic resonance (MR) imaging in patients with arrhythmia but without arrhythmogenic dysplasia.In 53 patients being evaluated for right ventricular arrhythmia and 15 control subjects, MR imaging was performed to evaluate fixed thinning, fatty replacement, or reduced systolic wall thickening or motion. A diagnosis of idiopathic right ventricular outflow tract tachycardia or indeterminate was assigned for each patient, and the severity of arrhythmia was categorized.Right ventricular abnormalities were revealed in 32 (60%) of the 53 patients: fixed thinning in 27 (84%), fatty replacement in eight (25%), and reduced wall thickening or motion in 31 (97%). Right ventricular abnormalities were found in 35 (76%) of 46 patients with idiopathic right ventricular outflow tract tachycardia and in seven (39%) of 18 patients with indeterminate diagnoses (P = .022).Mild right ventricular abnormalities are likely sources for arrhythmias, even in the absence of arrhythmogenic right ventricular dysplasia.