Preventing Arrhythmic Death in Patients With Tetralogy of Fallot

Highlights

• Patients with TOF remain at risk of lethal cardiac arrhythmias decades after initial surgical repair.

• Risk stratification should be based on noninvasive markers and judicious use of programmed ventricular stimulation in selected patients.

• Most ventricular arrhythmias after TOF repair involve monomorphic re-entrant ventricular tachycardia, although some involve slow-conducting pathways in the right ventricle amenable to catheter-based ablation.

• LV dysfunction is a powerful predictor of outcomes after TOF repair with or without pulmonary valve replacement.

Abstract

Patients with tetralogy of Fallot are at risk for ventricular arrhythmias and sudden cardiac death. These abnormalities are associated with pulmonary regurgitation, right ventricular enlargement, and a substrate of discrete, slowly-conducting isthmuses. Although these arrhythmic events are rare, their prediction is challenging. This review will address contemporary risk assessment and prevention strategies. Numerous variables have been proposed to predict who would benefit from an implantable cardioverter-defibrillator. Current risk stratification models combine independently associated factors into risk scores. Cardiac magnetic resonance imaging, QRS fragmentation assessment, and electrophysiology testing in selected patients may refine some of these models. Interaction between right and left ventricular function is emerging as a critical factor in our understanding of disease progression and risk assessment. Multicenter studies evaluating risk factors and risk mitigating strategies such as pulmonary valve replacement, ablative strategies, and use of implantable cardiac-defibrillators are needed moving forward.