Mitral Annular Substrate and Ventricular Arrhythmias in Arrhythmogenic Mitral Valve Prolapse With Mitral Annular Disjunction

BACKGROUND In patients with bileaflet mitral valve prolapse (MVP), mitral annular disjunction (MAD) is associated with increased risk of sudden cardiac death via incompletely understood mechanisms. OBJECTIVES This study assessed the substrate for ventricular arrhythmias in patients with bileaflet MVP and MAD as well as outcomes of catheter ablation with an emphasis on sustained, monomorphic ventricular tachycardia (VT). METHODS A total of 18 consecutive patients (11 women, mean age 54 +/- 15 years) with bileaflet MVP and MAD underwent catheter ablation for VT, and/or premature ventricular complexes (PVCs). Eight patients had a prior cardiac arrest. RESULTS PVCs were targeted for ablation in all 18 patients (symptomatic PVCs n = 15, PVC-induced ventricular fibrillation n = 3). Sustained monomorphic VT was targeted in 7 of 18 patients. Electroanatomic mapping showed low voltage in the area of the mitral annulus corresponding to VT target sites in 6 of 7 patients with sustained VT. Four of 7 patients had low voltage in the areas of MAD. Six of 7 patients with VT were rendered noninducible post-ablation. The PVC burden was reduced from 11.0% +/- 10.4% to 4.0% +/- 5.5% (P = 0.004). Over a mean follow-up of 33.9 +/- 43.4 months, no VTs recurred. There were no major complications. No repeat ablations for VT occurred. Five of 18 patients required repeat ablation for PVCs. CONCLUSIONS In patients with bileaflet MVP and MAD undergoing catheter ablation, the mitral valve annulus often contains low-voltage areas harboring the substrate for monomorphic VT and PVCs. Ablation in these patients was safe and improved arrhythmia control. (J Am Coll Cardiol EP 2023;9:1265-1275) (c) 2023 the American College of Cardiology Foundation. Published by Elsevier. All rights reserved.