| Verf.angabe: | Priya Chockalingam, MBBS, PHD, Lia Crotti, MD, PHD, Giulia Girardengo, MD, Jonathan N. Johnson, MD, Katy M. Harris, MS, RN, Jeroen F. van der Heijden, MD, PHD, Richard N.W. Hauer, MD, PHD, Britt M. Beckmann, MD, Carla Spazzolini, DVM, MS, Roberto Rordorf, MD, Annika Rydberg, MD, PHD, Sally-Ann B. Clur, MBBCH, MSC (MED), PHD, Markus Fischer, MD, Freek van den Heuvel, MD, PHD, Stefan Kääb MD, PHD, Nico A. Blom, MD, PHD, Michael J. Ackerman, MD, PHD, Peter J. Schwartz, MD, Arthur A.M. Wilde, MD, PHD |
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| Abstract: | Objectives The purpose of this study was to compare the efficacy of beta-blockers in congenital long QT syndrome (LQTS).Background Beta-blockers are the mainstay in managing LQTS. Studies comparing the efficacy of commonly used beta-blockers are lacking, and clinicians generally assume they are equally effective.Methods Electrocardiographic and clinical parameters of 382 LQT1/LQT2 patients initiated on propranolol (n = 134), metoprolol (n = 147), and nadolol (n = 101) were analyzed, excluding patients <1 year of age at beta-blocker initiation. Symptoms before therapy and the first breakthrough cardiac events (BCEs) were documented.Results Patients (56% female, 27% symptomatic, heart rate 76 ± 16 beats/min, QTc 472 ± 46 ms) were started on beta-blocker therapy at a median age of 14 years (interquartile range: 8 to 32 years). The QTc shortening with propranolol was significantly greater than with other beta-blockers in the total cohort and in the subset with QTc >480 ms. None of the asymptomatic patients had BCEs. Among symptomatic patients (n = 101), 15 had BCEs (all syncopes). The QTc shortening was significantly less pronounced among patients with BCEs. There was a greater risk of BCEs for symptomatic patients initiated on metoprolol compared to users of the other 2 beta-blockers combined, after adjustment for genotype (odds ratio: 3.95, 95% confidence interval: 1.2 to 13.1, p = 0.025). Kaplan-Meier analysis showed a ignificantly lower event-free survival for symptomatic patients receiving metoprolol compared to propranolol/nadolol.Conclusions Propranolol has a significantly better QTc shortening effect compared to metoprolol and nadolol, especially in patients with prolonged QTc. Propranolol and nadolol are equally effective, whereas symptomatic patients started on metoprolol are at a significantly higher risk for BCEs. Metoprolol should not be used for symptomatic LQT1 and LQT2 patients. |
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