Predictors of ventricular arrythmias in patients with Mitral Valve Prolapse – Cardiac MRI study

Introduction: The outcome of patients with mitral valve prolapse (MVP) largely depends on the presence of ventricular arrhythmias. Our aim was to evaluate the possible predictors of ventricular arrythmias among the patients with MVP from CMR study.

Methods: Consecutive patients (n = 45, mean age 56 ± 16 y) with MVP underwent a CMR scans. Premature ventricular beats (PVCS) and ventricular tachycardia (VT) were recorded by 24-hour Holter monitoring and exercise stress test. Late gadolinium enhancement (LGE) was calculated as percentage of left ventricular (LV) mass and was analyzed by tertiles – 1st tertile (≤ 1%), 2nd (2 – 5%) and 3rd tertile > 6% of LV mass. Mitral annular disjunction (MAD) was measured in millimeters in a 3-chamber cine sequence. Papillary muscle fibrosis (PMF) was identified from LGE sequence. The combined clinical endpoint (CEP) was defined as the presence of VT, multiform PVC, ablation due to multiple PVCs and new implantable cardioverter defibrillators insertion.

Results: The CEP was documented in 47% and 46% and 93% of the 1st, 2nd and 3rd LGE% tertiles, respectively (p for trend = 0.01). A logistic regression analysis to predict CEP including age, gender, LV ejection fraction, mitral regurgitation severity, MAD, PMF and LGE% demonstrating that LGE%, but not other confounders was an independent predictor of CEP as a continuous variable (OR 1.83; 1.04 - 3.21, P = 0.03) or 3rd tertile (OR 14.90; 1.53 – 144.22, P = 0.02).

Conclusion: Elevated LGE (> 6% of LV mass) was found to be an independent predictor of the CEP in MVP patients. These results highlight the potential role of myocardial fibrosis in MVP arrhythmias.