Effectiveness and limitations of beta-blocker therapy in congenital long-QT syndrome

Circulation. 2000 Feb 15;101(6):616-23. doi: 10.1161/01.cir.101.6.616.


Background: beta-blockers are routinely prescribed in congenital long-QT syndrome (LQTS), but the effectiveness and limitations of beta-blockers in this disorder have not been evaluated.

Methods and results: The study population comprised 869 LQTS patients treated with beta-blockers. Effectiveness of beta-blockers was analyzed during matched periods before and after starting beta-blocker therapy, and by survivorship methods to determine factors associated with cardiac events while on prescribed beta-blockers. After initiation of beta-blockers, there was a significant (P<0.001) reduction in the rate of cardiac events in probands (0.97+/-1.42 to 0.31+/-0.86 events per year) and in affected family members (0. 26+/-0.84 to 0.15+/-0.69 events per year) during 5-year matched periods. On-therapy survivorship analyses revealed that patients with cardiac symptoms before beta-blockers (n=598) had a hazard ratio of 5.8 (95% CI, 3.7 to 9.1) for recurrent cardiac events (syncope, aborted cardiac arrest, or death) during beta-blocker therapy compared with asymptomatic patients; 32% of these symptomatic patients will have another cardiac event within 5 years while on prescribed beta-blockers. Patients with a history of aborted cardiac arrest before starting beta-blockers (n=113) had a hazard ratio of 12.9 (95% CI, 4.7 to 35.5) for aborted cardiac arrest or death while on prescribed beta-blockers compared with asymptomatic patients; 14% of these patients will have another arrest (aborted or fatal) within 5 years on beta-blockers.

Conclusions: beta-blockers are associated with a significant reduction in cardiac events in LQTS patients. However, syncope, aborted cardiac arrest, and LQTS-related death continue to occur while patients are on prescribed beta-blockers, particularly in those who were symptomatic before starting this therapy.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adrenergic beta-Antagonists / administration & dosage*
  • Adrenergic beta-Antagonists / adverse effects
  • Adult
  • Atenolol / administration & dosage
  • Atenolol / adverse effects
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Long QT Syndrome / congenital
  • Long QT Syndrome / drug therapy*
  • Long QT Syndrome / physiopathology
  • Male
  • Metoprolol / administration & dosage
  • Metoprolol / adverse effects
  • Nadolol / administration & dosage
  • Nadolol / adverse effects
  • Propranolol / administration & dosage
  • Propranolol / adverse effects
  • Survival Analysis


  • Adrenergic beta-Antagonists
  • Nadolol
  • Atenolol
  • Propranolol
  • Metoprolol