Efficacy of Different Beta-Blockers in the Treatment of Long QT Syndrome

BACKGROUND In LQTS, beta-blocker therapy is effective in reducing the risk of cardiac events (syncope, aborted cardiac arrest, sudden cardiac death). Limited studies have compared the efficacy of different beta-blockers. OBJECTIVES The goal of this study was to compare the efficacy of different beta-blockers in long QT syndrome (LQTS) and in genotype-positive patients with LQT1 and LQT2. METHODS The study included 1,530 patients from the Rochester, New York-based LQTS Registry who were prescribed common beta-blockers (atenolol, metoprolol, propranolol, or nadolol). Time-dependent Cox regression analyses were used to compare the efficacy of different beta-blockers with the risk of cardiac events in LQTS. RESULTS Relative to being off beta-blockers, the hazard ratios and 95% confidence intervals (CIs) for first cardiac events for atenolol, metoprolol, propranolol, and nadolol were 0.71 (0.50 to 1.01), 0.70 (0.43 to 1.15) 0.65 (0.46 to 0.90), and 0.51 (0.35 to 0.74), respectively. In LQT1, the risk reduction for first cardiac events was similar among the 4 beta-blockers, but in LQT2, nadolol provided the only significant risk reduction (hazard ratio: 0.40 [0.16 to 0.98]). Among patients who had a prior cardiac event while taking beta-blockers, efficacy for recurrent events differed by drug (p = 0.004), and propranolol was the least effective compared with the other beta-blockers. CONCLUSIONS Although the 4 beta-blockers are equally effective in reducing the risk of a first cardiac event in LQTS, their efficacy differed by genotype; nadolol was the only beta-blocker associated with a significant risk reduction in patients with LQT2. Patients experiencing cardiac events during beta-blocker therapy are at high risk for subsequent cardiac events, and propranolol is the least effective drug in this high-risk group. (C) 2014 by the American College of Cardiology Foundation.