What are the risk factors and electrocardiographic findings associated with late sudden death in survivors of tetralogy of Fallot repair?
Older age at the time of tetralogy of Fallot repair is associated with an increased risk of late sudden death and frequent ventricular arrhythmias in long-term survivors.
Of 141 hospital survivors after intracardiac repair of tetralogy of Fallot, eight died suddenly 6–23 years later. Compared with the other 133 patients, these eight were older at operation, with higher post-repair systolic right ventricular pressure and more often complete atrioventricular block; ventricular arrhythmia was diagnosed before death in three cases. In follow-up totalling 2255 patient years, the linearized rate of sudden death was 0.35%/year. The instantaneous risk of sudden death showed continuous increase with the length of follow-up. Of 80 survivors electrocardiographically evaluated 13–26 (median 20) years postoperatively, none had complete block, but 79 had complete right bundle branch block, including seven with left anterior hemiblock. Ventricular extrasystoles were recorded in 1% at rest, in 34% during exercise and in 83% during 24-hour ambulatory monitoring, with Lown Grade ≥II in 27%. Old age and possibly presence of fibrosis and/or fibroelastosis in right ventricular outflow tract muscle correlated independently with high Lown Grade. A patient with Lown grade III died suddenly 2 years after our follow-up. Old age at repair thus was associated with increased risk of late sudden death and with frequent ventricular arrhythmia in long-term survivors.
Jonsson et al. (Sun,) studied this question.