Abstract 4372007: Perioperative Electrophysiological Study in Repaired Tetralogy of Fallot Undergoing Pulmonary Valve Replacement: A Systematic Review

Background: Patients with repaired Tetralogy of Fallot (TOF) undergoing pulmonary valve replacement (PVR) are at increased risk of major adverse ventricular arrhythmias and related events (MAREs). Perioperative electrophysiological study (EPS) has been used for risk stratification and guiding future management, but these studies are limited by small sample size. Objectives: To perform a systematic review of outcomes of pre-PVR EPS in TOF patients with PVR. Methods: A comprehensive search of PubMed, Embase, Scopus and Google scholar databases was performed per PRISMA 2020 guidelines. Studies on patients with repaired TOF undergoing PVR with perioperative EPS were included. Data were extracted on study design, sample size, EPS outcomes and MAREs during follow-up. Results: A total of 1,528 patients (age: 35.5±3.8 y; 57% male; LVEF: 57.1±1.5%, RVEF: 42.6±1.5%) were included from 12 studies. EPS was performed in 1212/1528 (79.3%), with sustained VT inducibility in 404 (33.3%)-monomorphic VT in 258 (63.8%), while 808 (66.6%) were non- inducible. 8/12 studies reported the type of PVR (transcatheter-36.8%). 174/293 (59.3%) inducible patients had an ablation (9 studies), while ICD (6 studies) was implanted in 70/263 (26.6%). Follow-up EPS (6 studies) showed 35/230 (15.2%) remained inducible. Overall,113 (9.3%) patients experienced MAREs over a median follow-up ranging from 6 months to 6.7 years. Sustained VT (11/12 studies) occurred in 70/1092 (6.4%), appropriate ICD therapy (7/12 studies) in 13/622 (2.1%) and sudden cardiac death (10/12 studies) in 30/906 (3.3%). Five studies provided MARE data stratified by VT inducibility. 12/164 (7.3%) inducible patients experienced MAREs, compared to 2/318 (0.6%) non-inducible patients. Reported risk factors for MAREs included older age at initial repair and PVR, QRS duration (>180ms), LVEF <45%, RVEF <35%, history of syncope, prior palliative shunts and atrial arrhythmias. Some studies identified MRI-derived scar burden, pulmonary annulus size, and RV/LV volume ratios as additional predictors. Conclusion: TOF patients remain at high risk of VA after PVR with 1/10 patients experiencing MAREs. People with inducible VT had a 12-fold greater risk than people who were non-inducible. EPS identifies a subset of TOF patients at higher arrhythmic risk during PVR and supports tailored ablation and ICD strategies. Prospective multicentre studies are needed to optimize integration of EPS and clinical risk models.