Altered response to ibutilide in a heart failure model

Sumeet S. Chugh, Susan B. Johnson, Douglas L Packer

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Objective: Despite the frequent use of anti-arrhythmic drugs in the general population, the electrophysiologic effects of these agents have not been elucidated in congestive heart failure (CHF). Methods: To examine the impact of left ventricular dysfunction on actions of type III anti-arrhythmic drugs, we evaluated the actions of ibutilide in a canine model of pacing-induced dilated cardiomyopathy. Following ablation of the atrioventricular node, effects on action potential duration at 90% (APD 90) were compared in vivo, between eight CHF animals and seven controls. Monophasic action potential recordings were obtained from right and left ventricular endocardium/epicardium during and after three doses of ibutilide (0.01, 0.02 and 0.05 mg/kg), at pacing cycle lengths of 300-1000 ms. Results: APD 90 prolongation with ibutilide (0.01 mg/kg) was significantly greater in CHF vs. controls (P=0.0026, ANOVA). However, plasma ibutilide levels at this dose, were not significantly different between the two groups. In CHF, maximal effects were observed at the lowest dose, whereas effects were gradual and dose-dependent in controls. With ibutilide administration (0.01 mg/kg), an increased dispersion of left-right ventricular APD 90 was observed in CHF, but not in controls (P=0.03). A trend was observed, for increased incidence of non-sustained polymorphic ventricular tachycardia in CHF. Conclusions: In the presence of CHF, the actions of ibutilide are altered significantly. These findings may reflect altered tissue effects, as a consequence of myocardial electrical remodeling in CHF. (C) 2001 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)94-102
Number of pages9
JournalCardiovascular Research
Volume49
Issue number1
DOIs
StatePublished - 2001

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Keywords

  • Antiarrhythmic agents
  • Heart failure
  • K-channel
  • Remodeling
  • Ventricular arrhythmias

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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