Clinical and electrophysiological properties of atrial tachycardia after pediatric heart transplantation.

ABSTRACT

BACKGROUND: Pediatric heart transplant recipients are at an elevated risk for development of atrial tachycardia (AT); however, the underlying mechanisms and long-term outcomes are unclear. OBJECTIVE: We hypothesized that occurrence of AT in pediatric heart transplant recipients would be associated with a higher frequency of adverse events during follow-up. METHODS: A single-center retrospective review of all pediatric heart transplant recipients with suspected AT between 1997 and 2017 was performed. Unaffected controls were matched with cases for age and transplant era. Clinical characteristics and long-term outcomes were compared between groups. RESULTS: Of 294 heart transplant recipients, 13 with AT at electrophysiology study (4.4%) were identified and compared with 29 controls. The most common mechanism was focal (11), followed by atrial flutter (two), and electrical reconnection of a surgical atrial anastomosis (two). Focal AT was only observed in the right atrium or atrial septum, and was frequently found on or near the crista terminalis. Relative to controls, cases exhibited more frequent clinical evidence of rejection (9/13 vs 10/29, P  =  0.037). For patients with AT, there was a higher rate of death/retransplant among cases (log-rank P  =  0.022), which remained significant in multivariate analysis. CONCLUSION: In this cohort, the most common form of AT after pediatric heart transplantation was focal, with predilection for sites near the crista terminalis. Transplant patients with AT experienced a higher rate of clinical rejection and the composite end-point of retransplantation or death relative to unaffected controls.