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Effect of angiotensin-converting enzyme therapy on QT interval dispersion

V Ranade1, J Molnar, T Khokher

  • 1The American Institute of Therapeutics and Rush University, Lake Bluff, IL 60044, USA.

American Journal of Therapeutics
|May 1, 2001
PubMed

Insights

Angiotensin-converting enzyme (ACE) inhibitors significantly reduced QT dispersion (QTd), a marker of electrical instability, in chronic heart failure patients. This reduction may explain the decreased risk of sudden death associated with ACE therapy.

Area of Science:

  • Cardiology
  • Pharmacology

Background:

  • Patients with chronic heart failure (CHF) face an elevated risk of sudden death, often linked to increased QT dispersion (QTd), indicating ventricular repolarization heterogeneity.
  • Angiotensin-converting enzyme (ACE) inhibitors are known to reduce heart size and improve outcomes in CHF.

Purpose of the Study:

  • To investigate whether ACE inhibitor therapy leads to a reduction in QTd, a key indicator of electrical instability in CHF patients.

Main Methods:

  • Ninety-seven patients with CHF were evaluated.
  • QTd and QTc dispersions were measured before and after 2 months of ACE inhibitor therapy.
  • Heart rate, ejection fraction, and ACE levels were also assessed.

Main Results:

  • ACE therapy resulted in a significant 25% reduction in normalized QTd (from 16 ± 4 to 12 ± 3).
  • QTd decreased from 61 ± 14 to 47 ± 12 (P < .001), and QTc dispersions decreased from 71 ± 18 to 52 ± 14 (P < .001).
  • Heart rate slowed significantly, and a strong negative correlation was observed between ejection fraction and QTd (r = -0.8; P < .001).

Conclusions:

  • ACE inhibitor therapy rapidly improves ventricular repolarization, evidenced by a significant reduction in QTd.
  • The observed decrease in QTd may contribute to the reduced risk of sudden cardiac death in CHF patients treated with ACE inhibitors.

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