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QT dispersion in patients with chronic heart failure: beta blockers are associated with a reduction in QT dispersion

C E Bonnar1, A P Davie, L Caruana

  • 1Department of Clinical Pharmacology and Therapeutics, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK. c.e.bonnar@clinpharm.dundee.ac.uk

Heart (British Cardiac Society)
|February 23, 1999
PubMed

Insights

QT dispersion is elevated in patients with systolic heart failure. Beta blockers may reduce this dispersion, suggesting an antiarrhythmic effect by improving ventricular repolarization.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Heart Failure Research

Background:

  • Left ventricular systolic dysfunction is associated with increased risk of arrhythmias.
  • QT dispersion is a measure of repolarization variability, and increased dispersion is linked to arrhythmogenesis.

Purpose of the Study:

  • To compare QT dispersion in patients with impaired left ventricular systolic function versus matched controls with normal function.
  • To investigate the effect of beta blockers on QT dispersion in these patient groups.

Main Methods:

  • A retrospective, case-control study involving 25 patients with impaired left ventricular systolic function and 100 controls.
  • QT and QTc dispersion were measured using three distinct methods.
  • Patients were matched for age, sex, prior myocardial infarction, and medication use (diuretics, beta blockers).

Main Results:

  • All measures of QT and QTc dispersion were significantly increased in patients with impaired left ventricular systolic function compared to controls (p < 0.001).
  • Beta blocker use was associated with a significant reduction in both QT and QTc dispersion (p < 0.05), irrespective of left ventricular function status.

Conclusions:

  • Increased QT and QTc dispersion are present in systolic heart failure patients, independent of measurement method or confounding factors.
  • Beta blockers demonstrate a potential antiarrhythmic mechanism by reducing ventricular repolarization dispersion.
Abstract

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