Characterizing Sustained Arrhythmias in Patients With Arrhythmic Mitral Valve Prolapse: Insights From the SAVE-MVP collaboration

Background: Arrhythmic mitral valve prolapse (AMVP) is a cause of sustained ventricular tachyarrhythmias (VAs) and sudden cardiac death (SCD), but the arrhythmias remain only partially understood. Objectives: In this worldwide collaboration, this study aimed to characterize the VAs occurring in AMVP patients, explore factors associated with various types of sustained VA, and describe common triggering mechanisms. Methods: In this multicenter retrospective cohort study, we collected patients with AMVP and documented VA. Clinical and imaging data, and detailed data of the arrhythmic events were collected. In addition, electrocardiograms or intracardiac tracings capturing the arrhythmic events were analyzed by a core laboratory. Results: We included 225 patients from 35 centers (age 44 ± 17 years, 57% female). Late gadolinium enhancement (LGE) was found in 61%. We collected 278 arrhythmic events, of which ventricular fibrillation (VF) was the most frequent (65%), followed by sustained monomorphic ventricular tachycardia (SMVT; 26%). Triggers were most commonly exercise or stress (37%), but 31% had no discernable trigger. SMVT was associated with increasing age (P = 0.03), family history of SCD (P = 0.03), history of syncope (P = 0.05), and myocardial LGE (P = 0.003). Of the 278 events, 140 (50%) had available tracings, where 25% of events were triggered by a short-coupled premature ventricular contraction. Pause-dependent initiation was most frequent (49%), and more likely to lead to VF than to SMVT (P = 0.01). Conclusions: The dominant VA in AMVP was VF, although SMVT was also common and associated with older age, family history of SCD, syncope, and myocardial LGE. The most common initiation was pause dependent leading to VF.