Clinical presentation of ventricular arrhythmias in patients with repaired Tetralogy of Fallot

Background: Many studies have investigated ventricular arrhythmias (VA) risk factors in patients with repaired Tetralogy of Fallot (TOF), but none have evaluated the clinical presentation of VA before and after pulmonary valve replacement (PVR). Objectives: This study examines the current VA prevalence and clinical presentation in patients with repaired TOF before and after PVR. Methods: Retrospective analysis performed on adult patients with repaired TOF from 1995 to 2021. Medical and surgical history, ECG, transthoracic echocardiogram, cardiac magnetic resonance imaging (MRI), cardiopulmonary exercise test (CPET) and 24-hour ECG Holter were evaluated. Results: Before PVR (154 patients, mean age 26 ± 11 years) 3.2 % of patients experienced sustained ventricular tachycardia (VT). Patients with VT were older at repair, presented more frequently with arrhythmic symptoms, QRS duration ≥180 ms, right ventricular outflow tract (RVOT) dysfunction with right ventricular (RV) dysfunction and complex premature ventricular complexes (PVC). All presented with monomorphic and hemodynamically tolerated VT, were referred after the VT episode and presented with longstanding RVOT dysfunction. After PVR (analysis performed on 85 patients, mean age 35 ± 13 years, mean follow-up 9 ± 1 years) VA incidence was not significantly different (6 %, equal to 0.7 % per year, p = .52). Two patients presented with resuscitated ventricular fibrillation (VF) related to short coupled PVC, while the others experienced monomorphic VT related to the development of a new hemodynamic lesion, all these patients received PVR after longstanding RVOT dysfunction with RV dysfunction. Conclusion: Currently the incidence of VA in patients with repaired TOF is low. Patients with VA are older at repair and more frequently present with longstanding RVOT dysfunction with RV dysfunction. While monomorphic VT are usually hemodynamically tolerated and rarely recurs after hemodynamic lesions resolution, VF related to short coupled PVC rarely can occur after PVR.