Cardiac transplantation in children and adolescents with long QT syndrome

Background Long QT syndrome (LQTS) is a potentially lethal, yet highly treatable, cardiac channelopathy. Cardiac transplantation has been reported anecdotally for patients with severe LQTS refractory to standard therapies. Objective The purpose of this study was to evaluate the incidence of and risk factors for cardiac transplantation in children evaluated and treated in an LQTS specialty center. Methods This was a retrospective review of 349 children with LQTS (mean age at diagnosis, 8.0 ± 5.7 years; mean corrected QT interval, 469 ± 51 ms; long QT syndrome type 1 [LQT1] in 46%, LQT2 in 31%, and LQT3 in 9%) evaluated from 2000 to 2013. A subset analysis was performed on patients referred for cardiac transplantation. Results Only 3 patients (0.9%; all LQT3; 2 female) underwent cardiac transplantation at ages 4, 11, and 17 years. Overall, 90 of 349 (26%) were symptomatic (exhibited LQTS-associated cardiac events) before LQTS diagnosis, including those who ultimately underwent transplant. Age at sentinel event was associated with transplantation (3 of 26 [12%] with an event at <1 year of life were transplanted vs 0 of 64 with an event after age 1; P =.02). Genotype was also a risk factor (3 of 32 patients with LQT3 were transplanted [9.4%] vs 0 of 270 patients with LQT1 or LQT2; P =.001). Before transplant, all patients had recurrent ventricular fibrillation–terminating shocks despite combination drug therapy and bilateral sympathetic denervation. All transplanted patients are alive at follow-up. Conclusion Cardiac transplantation is seldom necessary for the management of LQTS. However, patients with LQT3 and in utero/neonatal expressivity are at higher risk of treatment failure and refractory ventricular arrhythmias with standard therapy, and cardiac transplantation should be considered for this malignant subset of LQTS.