Po-04-194 prognostic significance of electrophysiologic testing for ventricular arrhythmias in patients with mitral annular disjunction

Mitral annular disjunction (MAD), with or without mitral valve prolapse (MVP), is associated with a higher risk of ventricular arrhythmias (VA) and sudden cardiac death. The prognostic significance of VA inducibility during electrophysiological studies (EPS) in patients with MAD is unclear. To assess the prognostic significance of VA inducibility in patients with MAD undergoing EPS. We included 21 patients with MAD and no history of sustained VAs who underwent EPS for risk stratification. Patients who underwent ablation of any VA during the same procedure were excluded. EPS protocol included programmed ventricular stimulation with up to triple extrastimuli and with burst pacing from 2 ventricular sites. Post-EPS events including sustained VAs, appropriate implantable-cardioverter defibrillator (ICD) shocks, and sudden death, were assessed according to the EPS results. Mean age at the time of EPS was 46±16 years, and 15 (71.4%) patients were female. Mean MAD length was 10±4 mm. 18 (85.7%) patients had MVP (bileaflet MVP in 15 patients and posterior MVP in 3 patients). Non-sustained ventricular tachycardia (NSVT) was induced in 2 (9.5%) patients, sustained monomorphic ventricular tachycardia (VT) in 4 (19%) patients, and ventricular fibrillation (VF) in 9 (42.9%) patients, while six (28.6%) patients had no inducible VAs. 10 (47.6%) patients underwent ICD implantation due to inducible sustained VT (n=4) or VF (n=6), while 5 (23.8%) patients received an implantable loop recorder (ILR). After a median follow-up of 18.9 months, 4 (19%) patients had incident sustained VT or VF, all among patients with an ICD. These events occurred in 2 of the 4 patients with inducible VT and 2 of the 9 with inducible VF, while no events occurred in those with inducible NSVT or no inducible VAs. Inducible sustained VT or VF at EPS did not demonstrate a statistically significant association with incident sustained VAs (p=0.13). No deaths occurred in any patients in this series. More than half of patients with MAD referred for risk stratification EPS had inducible sustained VT or VF. Inducibility of VT/VF was not statistically associated with incident sustained VAs though this analysis is limited by the small sample size. Larger prospective studies are needed to clarify the role of EPS with standardized protocols in the risk stratification of patients with MAD, including investigation of the value of right and left ventricular stimulation.