Abstract:

Background: Mitral valve prolapse (MVP) may be associated with ventricular arrhythmias (VA) even in the absence of significant valvular regurgitation. Curling, mitral annulus disjunction (MAD) and myocardial fibrosis (late gadolinium enhancement, LGE) may account for arrhythmogenesis.

Objectives. We investigated the determinants of VA in MVP patients without significant regurgitation.

Methods: 108 MVP patients (66 female; median age: 48 years) without significant regurgitation were included. All patients underwent 12-lead ECG, 12-lead 24-hour ECG Holter, exercise stress test and cardiac magnetic resonance (CMR). Patients were divided into two groups (arrhythmic and no-arrhythmic MVP), according to the presence of VA with a right bundle branch (RBBB) pattern.

Results: 62 patients (57%) with arrhythmic MVP showed: i) higher MAD (median length: 6 versus 3 mm; p=0.017), ii) higher prevalence of curling (79% versus 52%), iii) higher prevalence of LV LGE (79% versus 52%; p=0.01). Mediation analysis showed that curling had both a direct (p=0.03) and indirect effect mediated by LGE (p=0.04) on VA, while the association between MAD and VA was completely mediated by LGE. Patients with severe VA showed more pronounced morpho-functional alterations, in terms of MAD (7.0 mm versus 4.6 mm, p=0.005) and presence and severity of curling (respectively 31% versus 18%, p= 0.010 and 4 versus 3 mm, p=0.004), compared to those without severe VA.

Conclusions: In MVP patients the occurrence of VA with RBBB morphology is the expression of more severe morphological, mechanical and tissue alterations. Curling has both a direct and an indirect effect on VA.

Editor-in-Chief
Kalyanam Shivkumar, MD, PhD, FACC
 
CME Editor
Kenneth A. Ellenbogen, MD, FACC

Author
Kelvin N. V. Bush, MD, FACC

Important Dates
Date of Release: April 22, 2024
Term of Approval/Date of CME/MOC Expiration: April 21, 2025