Adipose replacement and wall motion abnormalities in right ventricle arrhythmias: evaluation by MR imaging. Retrospective evaluation on 124 patients

We reevaluated the magnetic resonance (MR) examinations of 38 healthy volun teers (control group, CG) and of 124 patients with RV arrhythmia with left bundle branch block (LBBB) morphology: 45 with episodes of RV sustained tac hycardia and of polymorphic RV premature beats (RVST-PPB group); 36 with on ly RV outflow tract sustained or not sustained tachycardia (RVOTT group); 4 3 with RV monomorphic premature beats (RVMPB group). All the examinations w ere reevaluated in a blinded fashion for detecting myocardial adipose repla cement (AR) and wall bulges or aneurysms. In RVST-PPB patients, no AR was o bserved in 9%; 1 RV region involvement, 0%; 2 regions, 4%; greater than or equal to 3 regions, 87%; left ventricle (LV), 15%. RVOTT patients: 0%, 53%, 14%, 5%, and 28%, respectively. RVMPB patients: 0%, 46%, 19%, 2%, and 33%, respectively. In CG, AR was observed in 11% (in RV outflow tract). RV bulg es were detected in 80% of RVST-PPB, 39% of RVOTT, and 14% of RVMPB patient s, none of the CG; RV aneurysms in 33% of RVST-PPB patients, none of RVOTT patients, RVMBP patients, and CG. A significant difference among groups for RV and LV AR as well as RV bulges and aneurysms was found (p < 0.0001). In the direct comparisons, significant differences were found for: disease du ration (RVST-PPB vs. RVMPB, p = 0.0396); RV AR (all the patients groups vs. CG, RVST-PPB vs. RVOTT or RVMPB, p < 0.0001); RV aneurysms (RVST-PPB vs. C G, RVST-PPB vs. RVOTT or RVMPB, p < 0.0002); bulges (all comparisons, p < 0 .0174). AR is confirmed as a structural substrate in RV arrhythmias. Number and extension of MR abnormalities are correlated to different degrees of R V arrhythmias.