Abstract 14051: QRS Duration After Pulmonary Valve Replacement in Adults With Repaired Tetralogy of Fallot: Prediction of Ventricular Arrhythmias and Correlation With Right Ventricular Size

Abstract

Background: Tetralogy of Fallot (ToF) patients face complications such as heart failure and ventricular arrhythmias (VA) after early repair which may be mitigated by pulmonary valve replacement (PVR). Prior studies have shown significant decreases in QRS duration and right ventricular (RV) size following PVR. We aimed to determine whether QRS duration reduction independently identifies patients at lower risk of VA and/or correlates with a decrease of RV size on cardiac magnetic resonance imaging (CMR) with long-term follow-up. Methods: We retrospectively identified patients ≥18 years old with repaired ToF who underwent surgical or transcatheter PVR, respectively, at our tertiary care center. Demographics, imaging, and ECGs (pre-PVR, 30 days to 1-year post-PVR, and closest to follow up CMR) were collected. Patients with ventricularly paced rhythm were excluded. The composite primary outcome was defined as sustained VT, ICD shock for sustained VT or inducible VT on EP study. Results: During the study period, 85 patients were included (median follow-up 3.6 years; median age 34 years; 51% females, 68% surgical PVR and median LVEF 56%). The primary outcome was observed in 8 (9.6%) patients. QRS duration decreased by 5 ms (pre-PVR mean 154±28 ms to 149±28ms post-PVR; p=0.0001). Increased age at PVR (OR 1.1 per year), QRS≥180ms post-PVR, no reduction in QRS after PVR (ΔQRS ≤ 0ms), and a history of VT were significantly associated with the composite outcome. (Table) The change in QRS was linearly correlated with the change in RVEDVi (R = 0.66; p=0.002). Conclusion: In conclusion, adults with repaired ToF experience a reduction in QRS duration post-PVR. This change correlates with the change in the RV size post-operatively. A QRS ≥180ms post-PVR, no reduction in QRS, increased age at repair, and a history of VT independently predict the occurrence of VT post-PVR. Patients with these risk factors may warrant closer monitoring and/or ICD consideration.