Role of magnetic resonance in the diagnosis of arrhythmogenic right ventricular dysplasia [Contributo diagnostico della risonanza magnetica nel sospetto clinico di displasia aritmogena del ventricolo destro]

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BACKGROUNDS: Magnetic Resonance (MR) imaging gives information about the complex anatomy of the right ventricle (RV). Because of the capability of tissue characterization, in addition to the functional and morphologic analysis, MR imaging is an optimal technique to investigate patients (pts) with clinical suspicion of arrhythmogenic right ventricular dysplasia (ARVD). METHODS: The purpose of the current study was to investigate a group of 55 pts with ventricular arrhythmias in order to detect ARVD. MR was performed with a 0.5 magnet (MR MAX PLUS G:E. Medical System). Electrocardiographically gated spin-echo and gradient-echo MR images of the heart were obtained in both transverse and sagittal planes. Sustained ventricular tachycardia (SVT) was present in 14 pts, non sustained ventricular tachycardia (NSVT) in 13 pts, left bundle block ventricular premature complexes > 10000/24 h (VPC/LBB) in 28 pts. The abnormalities analyzed were: presence of focal or diffuse fatty replacement of myocardium, segmental or global dilation of the RV, reduction of ejection fraction with akinetic or dyskinetic areas, disarrangement of the trabecular pattern with the hypertrophy of the moderator band. RESULTS: When intramyocardial fatty replacement and at least two of the abnormalities were present we considered the MR aspects compatible with the diagnosis of ARVD. We detected the presence of ARVD in 8/14 pts with SVT, in 4/13 pts with NSVT, in 4/28 pts VPC/LBB: In 10/16 pts with ARVD left ventricular abnormalities (areas of fatty replacement of the myocardial wall and/or reduction of ejection fraction) were also present. The left ventricular involvement was detected in 5 pts with SVT, in 2 pts with NSVT, in 3 pts with VPC/LBB: Even if in 31 pts it was not possible to identify aspects compatible with the diagnosis of ARVD, some structural abnormalities of RV were also present. Because of its non-invasiveness MR is an excellent technique for the detection of ARVD, and of minor right ventricular abnormalities.