265: Right atrial area and right ventricular outflow tract akinetic region length predict sustained tachyarrhythmia in repaired tetralogy of Fallot

Abstract

We investigated the significance of right atrial (RA) and right ventricular (RV) anatomy and function for arrhythmia prediction. Repaired tetralogy of Fallot (rtoF) patients are at risk of atrial or ventricular tachyarrhythmia and sudden cardiac death. One-hundred-and-fifty-four rtoF adults who underwent cardiovascular magnetic resonance (CMR) were studied with the pre-specified endpoint of new-onset atrial or ventricular arrhythmia (sustained ventricular tachycardia/ventricular fibrillation) during a a longitudinal follow-up. Median age was 31 (IQR:22-40), median follow-up was 5.6 (IQR:4.6-7.0) years Atrial tachyarrhythmia (n=11) was predicted by maximal right atrial area indexed to body surface area (RAAi) on cine-CMR (Hazard ratio; HR1.17, 95%CI 1.07-1.28 per cm 2 /m 2 ; P=0.0005, survival ROC curve analysis, area under curve; AUC 0.74[0.66-0.81]; cut-off value 16 cm 2 /m 2 ). Atrial arrhythmia-free survival was reduced in patients with RAAi ≥ 16 cm 2 /m 2 (Logrank; P=0.0001). RV restrictive physiology on echocardiography (n=38) related to higher RAAi (P=0.02) but did not predict atrial tachyarrhythmia (P=0.057). RV restrictive physiology patients had similar RV dilatation and exercise impairment to remaining patients representing a different phenotype from previous reports. Ventricular arrhythmia (n=9) was predicted by CMR RV outflow tract (RVOT) akinetic area length (HR1.05, 95%CI 1.01-1.09 per mm; P=0.003, survival ROC analysis, AUC 0.77[0.83-0.61]; cut-off value 30 mm) and decreased RV ejection fraction (HR0.93 95%CI 0.87-0.99 per %; P=0.03, respectively). Ventricular arrhythmia-free survival was reduced in patients with RVOT akinetic region length >30 mm (Logrank;P=0.02). RAAi predicts atrial arrhythmia and RVOT akinetic region length predicts ventricular arrhythmia in late follow-up of rtoF. These are simple, feasible measurements for serial surveillance and risk stratification of rtoF patients.