Risk of cardiac tachyarrhythmia in patients with repaired tetralogy of Fallot: a multicenter cardiac MRI based study

Cardiac tachyarrhythmias are the leading cause of morbidity and mortality in patients with repaired tetralogy of Fallot (TOF). We evaluated risk factors for sustained ventricular tachyarrhythmia (VT) and atrial tachyarrhythmia (ATA) in these patients. Patients (n=319) who underwent cardiac magnetic resonance (CMR) imaging at two tertiary centers between 2007 and 2016 were assessed. Potential risk markers, based on history, cardiac magnetic resonance imaging (CMR), electrocardiography (ECG) and echocardiography, were analyzed for prediction of the primary endpoint of VT, and the secondary endpoint of ATA. During a follow-up of 3.5 (0.9-6.1) years, 20 (6.3%) patients reached the primary endpoint, and 30 (9.4%) the secondary endpoint. Multivariable cox hazards regression identified right ventricular (RV) end-diastolic volume (Hazard ratio [HR] 2.03, per 10ml/m(2) increase; p=0.02), RV end-systolic volume (HR 3.04, per 10ml/m(2) increase; p=0.04), RV mass (HR 1.88, per 10g/m(2) increase; p=0.02), and RV ejection fraction (HR 6.06, per 10% decrease; p=0.02) derived from CMR to be independent risk factors of VT. In addition, QRS-duration (HR 1.70, per 10ms increase; p=0.001) and body mass index (BMI: HR 1.8, per 5kg/m(2) increase; p=0.02) were independent markers of VT. Older age at TOF repair (HR 1.33, per 2months increase; p=0.03) and BMI (HR 1.76, per 5kg/m(2) increase; p<0.001) independently predicted ATA. RV systolic dysfunction, hypertrophy and dilatation on CMR, together with QRS prolongation, and obesity are predictive of VT in TOF patients. Older age at TOF repair and obesity were associated with the occurrence of ATA.