Sudden death prior to pediatric heart transplantation: would implantable defibrillators improve outcome?

Objectives: The goal of this study is to determine the incidence of sudden cardiac death in children with cardiomyopathy prior to pediatric heart transplantation.

Background: Recent primary prevention trials of implantable cardiac defibrillator (ICD) therapy in adults with ischemic and non-ischemic cardiomyopathy have shown a survival benefit. The incidence of sudden death, and thus the likelihood of improved survival with ICD therapy, in children with cardiomyopathy is currently unknown.

Methods: The Pediatric Heart Transplant Study (PHTS) database was retrospectively queried for patients < or =18 years of age who died from any cause after listing for but prior to heart transplantation. Patients having arrhythmic or sudden death were included for study. Clinical and demographic variables were examined to identify higher-risk sub-groups.

Results: Of the 2,392 patients in the PHTS database, 420 (17.6%) died prior to heart transplantation. Only 32 deaths (1.3% of total listed, 7.6% of total deaths) were sudden or arrhythmic in nature. Patients with ischemic cardiomyopathy had an increased risk of sudden death (relative risk = 6.92). Presence of congenital heart disease and United Network for Organ Sharing (UNOS) status at listing were not associated with an increased risk of sudden death.

Conclusions: The overall incidence of sudden death in children awaiting heart transplantation is low; therefore, uniform implantation of ICDs for the primary prevention of sudden death is unlikely to improve survival in this population. Children with ischemic cardiomyopathy appear to have a higher risk of sudden death and may benefit from ICD therapy.