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Published on: December 11, 2017

Effects of carvedilol therapy on arrhythmia markers in patients with congestive heart failure

Bahri Akdeniz1, Sema Guneri, Ilke Z Savas

  • 1Department of Cardiology, Dokuz Eylul University School of Medicine, Inciralti, Izmir, Turkey.

International Heart Journal
|September 9, 2006
PubMed

Insights

Carvedilol therapy in heart failure patients significantly improved ventricular repolarization by reducing QT dispersion (QTd). However, it did not alter autonomic dysfunction, indicating a specific effect on repolarization rather than overall autonomic balance.

Area of Science:

  • Cardiology
  • Pharmacology
  • Electrophysiology

Background:

  • Heart failure (HF) is associated with impaired ventricular repolarization and autonomic dysfunction.
  • QT dispersion (QTd) and heart rate variability (HRV) are markers of repolarization and autonomic function, respectively.
  • Carvedilol, a beta-blocker, has shown benefits in HF, but its specific effects on repolarization and autonomic function require further elucidation.

Purpose of the Study:

  • To investigate the impact of carvedilol therapy on ventricular repolarization characteristics, assessed by QT dispersion (QTd) and corrected QTd (QTcd).
  • To evaluate the effects of carvedilol on heart rate variability (HRV) as a measure of autonomic function in heart failure patients.

Main Methods:

  • A prospective controlled study involving 31 heart failure patients treated with carvedilol and 14 control patients.
  • Measurements included QT dispersion (QTd), corrected QTd (QTcd), and heart rate variability (HRV) via Holter ECG at baseline and after 6 months.
  • Carvedilol was administered at 6.25 mg/day and titrated to the maximum tolerated dose.

Main Results:

  • Carvedilol therapy significantly reduced QTd (P=0.016) and QTcd (P=0.001).
  • The QT minimum value increased significantly (P=0.03) after carvedilol treatment.
  • While mean SDANN (P=0.039) improved, other HRV parameters did not show significant changes.

Conclusions:

  • Carvedilol therapy improves ventricular repolarization characteristics in heart failure patients by decreasing QT dispersion.
  • Carvedilol treatment does not significantly alter autonomic dysfunction in this patient population.
  • These findings suggest a direct effect of carvedilol on repolarization independent of autonomic modulation.

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