Tetralogy of Fallot: electrophysiology-guided surgical ablation during pulmonary valve replacement

BACKGROUND AND AIMS: Adults with repaired tetralogy of Fallot (TOF) face long-term risks of ventricular tachycardia (VT) and sudden cardiac death (SCD). There is no consensus on arrhythmia management during surgical pulmonary valve replacement (PVR). This study assessed whether pre-operative electrophysiological (EP) testing with targeted intraoperative cryoablation of identified anatomical isthmuses during PVR is associated with a reduction in post-operative VT inducibility and long-term risk of clinical VT/SCD. METHODS: In this prospective multicentre cohort study, consecutive adults with TOF undergoing surgical PVR (2005-22) underwent standardized pre-operative EP studies. Surgical ablation strategy (EP-guided vs empiric) was at the discretion of the treating team. Post-operative EP studies assessed residual inducibility; clinical VT/SCD were evaluated during follow-up. RESULTS: Among 204 patients (age 35.5 ± 13.1 years, 43.1% female), 91 (45.1%) had inducible VT. Among those undergoing surgical ablation, post-operative VT was non-inducible in 74.1% with EP-guided vs 15.0% with empiric ablation adjusted odds ratio 20.4, 95% confidence interval (CI) 4.5-91.8, P < .0001. Persistent post-operative inducibility was associated with increased hazard of VT/SCD compared to patients without inducible VT pre-operatively adjusted hazard ratio (HR) 5.3, 95% CI 1.8-16.0, P = .003, over a median 10.2-year follow-up. Compared to patients without inducible VT pre-operatively, empiric ablation was associated with a significantly higher hazard of VT/SCD (HR 5.2, 95% CI 1.6-16.5, P = .005), whereas EP-guided ablation was not (HR 2.8, 95% CI 0.8-10.3, P = .228). CONCLUSIONS: In adults with repaired TOF undergoing PVR, inducible VT is common. An EP-guided surgical strategy is associated with greater post-operative non-inducibility and improved long-term arrhythmic outcomes compared with empiric ablation.