Predictors of and outcomes in arrhythmic mitral valve prolapse

Abstract

Abstract Background Recently, the European Heart Rhythm Association (EHRA) defined the phenotype of the arrhythmic mitral valve prolapse (AMVP) complex and proposed management approaches. Assessing the incidence of SCD in this small subset of patients is challenging due to the low event-rate and longitudinal real-world data remain scarce. Purpose To determine the predictors of AMVP and study the clinical outcome of patients stratified by ICD indication as proposed by the EHRA consensus statement. Methods All consecutive patients with MVP who underwent cardiac magnetic resonance imaging (CMR) were enrolled in a single-center retrospective registry. AMVP was defined as the presence of frequent or complex ventricular arrhythmias (>5% total PVC burden, non-sustained ventricular tachycardia (VT), VT or ventricular fibrillation) in a patient with MVP without alternative arrhythmic substrates. The medical records of these patients included a comprehensive clinical, rhythmic and echocardiographic characterization allowing to collect the key date of transition to AMVP. A forward conditional multivariable logistic regression was performed to identify clinical risk factors for AMVP reporting the odds ratio (OR) and corresponding 95% confidence interval (95% CI). Incidence rates were calculated for the composite endpoint of SCD, sustained VT, ICD shocks, and all-cause mortality. Results A total of 169 patients (52.1% male, median age 51.4 years) were included, of which 99 (58.6%) were classified as AMVP. Clinical characteristics are presented in Image 1. Patients with non-arrhythmic MVP and AMVP had comparable left ventricular function, mitral valve regurgitation grade and extent of MVP. Multivariable logistic regression identified the presence of late gadolinium enhancement (LGE, OR 2.82, 95%CI 1.45–5.50, p=0.002) and mitral annular disjunction (MAD, OR 1.98, 95%CI 1.02–3.86, p=0.045) on CMR as only predictors of AMVP. Cardiac CMR results are presented in Image 2. The median overall follow-up since first cardiac contact was 8.0 years (IQR 5.0–15.6), while this was 5.0 years (IQR 2.1–7.4 years) after transition to AMVP. The incidence for the composite endpoint in the overall population was 0.4%/year (95%CI 0.2 – 0.9). The 5-year cumulative event rate was 1.8%. According to the EHRA risk stratification the implantation of an ICD would have been reasonable in 69 patients (69.7%). In total, 5 patients were implanted with an ICD for secondary prevention, but all those patients did not classify as AMVP prior to the life threathening arrhythmic event. Conclusion CMR is an important tool in the challenging risk stratification of AMVP given that the presence of MAD and LGE enhancement are predictors of AMVP. There is a lack of longitudinal data to determine when patients transition from MVP to AMVP and how this modifies their outcome.Clinical characteristics and ECG resultsOverview of CMR measurements