Perioperative electrophysiology study in patients with tetralogy of Fallot undergoing pulmonary valve replacement will identify those at high risk of subsequent ventricular tachycardia

Abstract

Ventricular tachyarrhythmias are the most common cause of death in patients with repaired tetralogy of Fallot (TOF), but predicting those at risk remains a challenge. An electrophysiology study (EPS) has been proposed to risk stratify patients with TOF. We sought to evaluate a perioperative EPS-guided approach to risk stratify patients with TOF undergoing pulmonary valve replacement (PVR) and guide concomitant cryoablation. A prospective cohort study of patients with TOF undergoing an EPS at the time of PVR from 2006 to 2017 was conducted at 2 centers. Patients inducible at the time of pre-PVR had undergone concomitant cryoablation in addition to PVR. A repeat post-PVR EPS was performed in those initially inducible to guide implantable cardioverter-defibrillator (ICD) implantation. Of 70 patients who underwent a pre-PVR EPS, 34 (49%) had inducible sustained ventricular tachycardia (VT): 25 monomorphic VT and 9 polymorphic VT. Among patients undergoing cryoablation, 14 (45%) had inducible VT and underwent ICD implantation. During a mean follow-up period of 6.1 ± 3.2 years, 3patients (21%) had appropriate ICD shocks for symptomatic VT. There was an average of 2.3 shocks (range 1-4 shocks), and the mean time to first shock post-device implantation was 3.6 years (range 2.9-4.3 years). Among patients with negative pre- or post-PVR EPS results, 2 had VT requiring radiofrequency ablation and/or subsequent ICD implantation. There were no arrhythmic deaths. A pre-PVR EPS identified patients with higher-risk TOF undergoing PVR. Despite empirical VT cryoablation at the time of PVR, a high percentage of patients remained inducible for VT. In this high-risk cohort, post-PVR EPS evaluation is important to identify patients at risk of VT despite cryoablation.