Long-term outcomes following electrophysiology study for ventricular arrhythmia evaluation in congenital heart disease: A retrospective cohort study.

BACKGROUND: Risk stratification for ventricular arrhythmia in congenital heart disease (CHD) remains challenging, and the role of programmed ventricular stimulation is incompletely defined. OBJECTIVE: This study evaluated long-term outcomes after electrophysiology study (EPS) for ventricular arrhythmia assessment in CHD practice. METHODS: Retrospective, single-center cohort study including consecutive patients with structural CHD who underwent EPS with programmed ventricular stimulation for ventricular arrhythmia evaluation between 1995 and 2022. Baseline characteristics were compared between inducible (EPS+) and non-inducible (EPS-) patients. The primary outcomes were a composite of all-cause mortality and heart transplantation (HTX) and a composite ventricular arrhythmia (VA) outcome. RESULTS: Among 174 patients, median age at EPS was 33.8 years (IQR 24.1-46.1), 65 (37.4%) were female, 106 (60.9%) had conotruncal CHD, and 37 (21.3%) were EPS+. EPS + patients more often had conotruncal CHD, abnormal RVEF, and longer PR and QRS duration. During a median follow-up of 13.0 (8.1-19.4) years, there was no significant difference in mortality/HTX (EPS+ 24.3% vs EPS- 18.2%, log-rank p = 0.924) or VA outcome (EPS+ 27.0% vs 12.4%, log-rank p = 0.113) between EPS+ and EPS- patients. After a median time of 2.8 (0.3-4.5) years 28 EPS- patients (20.4%) received an ICD. Of these, 16 (57.1%) received the ICD for out-of-hospital cardiac arrest or sustained ventricular tachycardia. CONCLUSIONS: In patients with CHD referred for EPS for ventricular arrhythmia evaluation, a positive EPS was associated with a distinct phenotype but not with worse long-term mortality/HTX or VA outcome. A negative EPS did not exclude clinically relevant arrhythmic risk.