Author + information
- Abeer Abuzeitone,
- Derick R. Peterson,
- Scott McNitt,
- Bronislava Polonsky,
- Martin Ruwald,
- Valentina Kutyifa and
- Arthur Moss
In inherited Long QT Syndrome (LQTS) cardiac events can range from frequent syncopal episodes to life-threatening cardiac arrhythmias. β-blocker therapy is effective in reducing the risk of cardiac events in LQTS patients and they are considered the first line of standard therapy. Pharmacodynamic differences between different β-blocker agents such as selectivity to blocking β-adrenergic receptors and adverse effects are well established, but the differential efficacy between different β-blockers used in LQTS has had only limited study.
The study population is drawn from the US portion of the International Long QT-Syndrome Registry and comprises 1,570 patients who reported β-blocker use at any time and had no history of Implantable Cardioverter Defibrillator (ICD) before the initiation of β-blockers. The logrank test was used to compare the risk of first cardiac event (syncope, aborted cardiac arrest, or LQTS-related death) by initially prescribed β-blocker, starting when one of the four common β-blockers was initiated and censoring when patients switched or went off β-blockers, reached age 40, or had an ICD implanted. Cox regression was used to estimate the hazard ratio for each of the β-blockers relative to those who went off β-blockers, with adjustment for relevant covariates.
There was a significant difference in time to first cardiac event following β-blocker initiation among the four β-blockers (p=0.04). Drug-specific hazard ratios (HR) for the risk of first cardiac event (CE) following β-blocker initiation, relative to going off β-blockers: nadolol HR=0.53, p< 0.001, (CE/n = 53/266); metoprolol HR=0.59, p=0.02, (30/160); atenolol HR=0.70, p=0.04, (92/448); propranolol HR=0.78, p=0.13, (234/696).
Different β-blockers are not equally effective in reducing the risk of first cardiac event following β-blocker initiation in LQTS patients, with nadolol the most and propranolol the least effective of the commonly used β-blockers.
Poster Sessions, Expo North
Sunday, March 10, 2013, 3:45 p.m.-4:30 p.m.
Session Title: Arrhythmias: AF/SVT VII
Abstract Category: 14. Congenital Cardiology Solutions: Therapy
Presentation Number: 1236-40
- 2013 American College of Cardiology Foundation