Tachyarrhythmias after pediatric heart transplantation.

BACKGROUND: Tachyarrhythmias in pediatric post-heart transplant patients are not well defined. In this study we sought to further characterize these arrhythmias in terms of presentation, course, and outcome.
METHODS: This investigation was a retrospective review of heart transplant recipients at St. Louis Children's Hospital during the period of 1991 to 2006. Patients were excluded if they were >18 years at transplantation or if follow-up information was unavailable. Patients with tachyarrhythmias beyond the first 2 weeks post-transplant were identified.
RESULTS: Twenty-eight tachyarrhythmias occurred in 25 of 237 heart transplant recipients. Freedom from arrhythmia was 92% at 1-year post-transplant and 86% at 15 years post-transplant. Intra-atrial reentry tachycardia (12 patients) and ectopic atrial tachycardia (10 patients) were the most common arrhythmias. Rejection was found in 3 (12%) and previously unrecognized coronary disease was found in another 2 (8%) at the time of presentation with arrhythmia. Fifteen of 25 (60%) were asymptomatic at presentation, but 4 of 25 (16%) presented with heart failure, including 3 without evidence of rejection. No risk factors for developing arrhythmia were identified. Twenty-one arrhythmias resolved with brief pharmacologic or no therapy. Only 3 had a recurrence after the initial arrhythmia. Five patients underwent catheter ablation.
CONCLUSIONS: Our experience suggests that the presence of tachyarrhythmias after pediatric heart transplantation is not rare and usually not associated with rejection. Pediatric heart transplant recipients have a higher incidence of ectopic atrial tachycardia (EAT) than their adult counterparts. Most tachyarrhythmias resolve after a relatively brief period of medical treatment and recurrence is uncommon.