Electrophysiologic effects of encainide on acutely ischemic rabbit myocardial cells

Samuel S. Wong, Robert J. Myerburg, Alan M. Ezrin, Henry Gelband, Arthur L. Bassett

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The electrophysiologic effects of encainide were determined in normal and acutely ischemic (30 min) rabbit ventricular muscle cells. Encainide (10-6, 5 × 10-5 M) had no effect on resting potential (RP); 10-6 encainide reduced overshoot and action potential (AP) amplitude of cells in normal left ventricles and cells in normal areas of ischemic ventricles. Encainide, 5 × 10-6 M and 10-5M, depressed V̇max and prolonged AP duration of normalcells. Surviving cells within ischemic areas displayed AP with reduced RP, overshoot, AP amplitude, V̇max and shorterned AP duration. All encainide concentrations reduced overshoot, AP amplitude and V̇max of depressed AP. Encainide's lengthening of AP duration was greater in cells within ischemic areas than in surrounding normal cells. Encainide (10-6 M) prolonged effective refractory period and often AP in ischematic cells. Encanides also caused depression in membrane responsiveness. Encainide's differential effect upon AP may significantly contribute to its antiarrhythmic activity in ischemic heart disease.

Original languageEnglish (US)
Pages (from-to)323-329
Number of pages7
JournalEuropean Journal of Pharmacology
Volume80
Issue number4
DOIs
StatePublished - Jun 4 1982

Keywords

  • Action potential
  • Antiarrhythmic
  • Effective refractory period
  • Encainide
  • Ischemia
  • Membrane responsiveness

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Pharmacology

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