Risk factors for arrhythmia and sudden cardiac death late after repair of tetralogy of Fallot: a multicentre study

Background Ventricular arrhythmia and sudden cardiac death tate after repai r of tetralogy of Fallot are devastating complications in adult survivors o f early surgery, but their prediction remains difficult. Methods We examined surgical, electrocardiographic, and late haemodynamic d ata, and their relation to clinical arrhythmia and sudden death occurring o ver 10 years, in a multicentre cohort of patients with repaired tetralogy, who were alive in 1985. Results Of 793 patients (mean age at repair 8.2 years [SD 8], mean time fro m repair 21.1 years [8.7]) who entered the study, 33 patients developed sus tained monomorphic Ventricular tachycardia, 16 died suddenly, and 29 had ne w-onset sustained atrial flutter or fibrillation. Electrocardiographic mark ers (QRS duration, QRS rate of change between 1985 and 1995) were significa ntly greater in the Ventricular tachycardia and sudden-death groups. Older age at repair was associated with a higher risk of sudden death and atrial tachyarrhythmia. Pulmonary regurgitation was the main underlying haemodynam ic lesion for patients with ventricular tachycardia and sudden death, where as tricuspid regurgitation was for those with atrial flutter/fibrillation. Despite adverse haemodynamics, no patient who died suddenly had undergone l ate reoperation. Conclusion Arrhythmia and sudden death are important late sequelae for: pat ients after repair of tetralogy of Fallot. The electrophysiological and hae modynamic substrate of sudden death resembled that of sustained ventricular tachycardia, with pulmonary regurgitation being the predominant haemodynam ic lesion. Preservation or restoration of pulmonary Valve function may thus reduce the risk of sudden death. Furthermore, electrocardiographic markers can help to identify patients at risk.