High Efficacy of β-Blockers in Long-QT Syndrome Type 1

Abstract

Background— β-Blocker efficacy in long-QT syndrome type 1 is good but variably reported, and the causes of cardiac events despite β-blocker therapy have not been ascertained. Methods and Results— This was a retrospective study of the details surrounding cardiac events in 216 genotyped long-QT syndrome type 1 patients treated with β-blocker and followed up for a median time of 10 years. Before β-blocker, cardiac events occurred in 157 patients (73%) at a median age of 9 years, with cardiac arrest (CA) in 26 (12%). QT-prolonging drugs were used by 17 patients; 9 of 17 (53%) had CA compared with 17 of 199 nonusers (8.5%; odds ratio, 12.0; 95% confidence interval, 4.1 to 35.3; P P P =0.001). None of the 26 patients with CA before β-blocker had CA/sudden death on β-blockers. Conclusions— β-Blockers are extremely effective in long-QT syndrome type 1 and should be administered at diagnosis and ideally before the preteen years. β-Blocker noncompliance and use of QT-prolonging drug are responsible for almost all life-threatening “β-blocker failures.” β-Blockers are appropriate therapy for asymptomatic patients and those who have never had a CA or β-blocker therapy. Routine implantation of cardiac defibrillators in such patients does not appear justified.