RIGHT-VENTRICULAR OUTFLOW TRACT VENTRICULAR-TACHYCARDIA - DETECTION PREVIOUSLY UNRECOGNIZED ANATOMIC ABNORMALITIES USING CINE MAGNETIC-RESONANCE-IMAGING

Objectives. This study attempted to determine whether cine magnetic re sonance imaging (MRI), because of its unique ability to image the righ t ventricle, detects abnormalities in patients with right ventricular outflow tract ventricular tachycardia. Background. Right ventricular o utflow tract ventricular tachycardia occurs in the absence of apparent structural heart disease. Methods. We compared cine MRI scans in 22 p atients with right ventricular outflow tract ventricular tachycardia, 16 subjects without structural heart disease and 44 patients with othe r cardiovascular diseases. Echocardiography was performed in 21 patien ts with ventricular tachycardia. Results. All 22 patients with ventric ular tachycardia had normal left ventricular function and no evidence of coronary artery disease. Cine MRI revealed right ventricular struct ural and wall motion abnormalities more often in patients with ventric ular tachycardia (21 [95%] of 22) than in normal subjects (2 [12.5%] o f 16, p < 0.0001) or patients without arrhythmia (17 [39%] of 44, p < 0.0001). The abnormalities in patients with ventricular tachycardia (f ixed focal wall thinning, excavation, decreased sys tolic thickening) were located in the right ventricular outflow tract, whereas those in patients without arrhythmia were confined to the free wall. Cine MRI d emonstrated abnormalities in patients with ventricular tachycardia mor e often than did echocardiography (21 [95%] of 22 vs. 2 [9%] of 21, re spectively, p < 0.0001). Conclusions. Right ventricular outflow tract ventricular tachycardia was associated with focal structural and wall motion abnormalities of the right ventricular outflow tract that were detected more often by cine MRI than by other imaging modalities and w ere not present in patients without arrhythmia or in normal subjects.