CMR evaluation in patients with high grade ventricular arrhythmias

Purpose:To assess by cardiac-MR the prevalence of myocardial alterations in arrhythmic patients. Materials and methods:43 patients with non ischemic ventricular arrhythmias. Premature ventricular complexes had left bundle branch block morphology (LBBB) in 29 cases, in 7 a right bundle branch block contour (RBBB) and 7 had polymorphic patterns(PV). US was negative in 78.4% of patients, while CMR was negative in only 13% of patients. Studies were performed on a 1.5 MR scanner with Cine sequences (Fastcard or FIESTA), bb-FSE and IR-prep FGRE 15 minutes after injection of 0.2 mmol/Kg of Gd-DTPA. Results: CMR found a high prevalence of morphological, signal intensity and functional myocardial abnormalities. RV dilatation was found in 85% of patients with PV arrhythmias, 48.3% of patients with LBBB morphology, 12.5% of patients with RBBB morphology. LV dilatation was present in 28.6%, 25% and 24.1% of patients with LBBB, PV and RBBB type arrhythmias respectively. RV wall motion abnormalities were identified in 50% and 36.7% of patients with PV and LBBB pattern respectively while LV motion abnormalities in 25% and 10.3%. Free wall RV signal/thickness abnormalities were found in 23.3% of patients; LV signal abnormalities were found in 11.6% of patients.Seven patients underwent myocardial biopsy: 5 positive for myocarditis, 1 positive for ARVD, one had a negative biopsy. Conclusions: In patients with primary ventricular arrhythmias MR documented high prevalence (87%) of morphological, signal intensity and wall motion abnormalities even with negative echocardiogram.