Left ventricular origin of arrhythmia predicts severe outcome in mitral valve prolapse: Insights from long-term cardiac monitoring

Background Diagnostic criteria and risk stratification in patients with arrhythmic mitral valve prolapse (AMVP) are insufficient. The current AMVP diagnosis defined by EHRA includes burden of premature ventricular complexes (PVCs) but not the origin of PVCs. Objective We aimed to assess left ventricular PVCs (LV-PVCs) as a risk factor for subsequent ventricular arrhythmia (VA) assessed by implantable cardiac monitor (ICM). We retrospectively applied the 2022 EHRA AMVP definition on our pre-2022 patient cohort. Methods We prospectively implanted ICM in patients with MVP and/or mitral annular disjunction during 2015-2020 and followed them for 3 years. We assessed occurrence of severe VA (ventricular fibrillation, sustained ventricular tachycardia [VT], or non-sustained VT [NSVT] causing syncope) and VA (severe VA and NSVT). PVCs origins were classified on 12-lead ECG. Results We included 60 patients (mean age 49±15years) with ICM. LV-PVCs were present in 30 (50%) patients. Hundred VAs were detected, 96 NSVTs and 4 severe VA. LV-PVCs were associated with VA incidence rate ratio of 10.77 (95%CI 3.23-36.06, p<0.001), adjusted for baseline NSVTs and PVC burden. Severe VA occurred only in patients with LV-PVCs (log-rank p=0.04). The 2022 EHRA AMVP definition detected patients with subsequent VA with AUC 0.63, however, missed one (2%) patient with severe VA, and missed 12 (25%) patients with subsequent NSVT due to PVCs <5% at baseline. Conclusion Presence of LV-PVCs was strongly associated with subsequent VA. The threshold of ≥5% PVCs for AMVP diagnosis appeared too high to detect MVP patients at risk of subsequent VA in our cohort.