Free oxygen radicals contribute to high incidence of reperfusion-induced arrhythmias in isolated rat heart

Life Sci. 1999;65(18-19):1927-30. doi: 10.1016/s0024-3205(99)00449-x.

Abstract

Early period of reperfusion of ischemic myocardium is associated with a high incidence of severe tachyarrhythmias including ventricular tachycardia and fibrillation (VT and VF). Free oxygen radicals (FOR) have been identified as one of the principal factors responsible for reperfusion-induced events. However, their role in arrhythmogenesis is not clear. In the present study, in isolated Langendorff-perfused rat hearts subjected to 30 min global ischemia, the onset of reperfusion induced 100% incidence of both VT and VF with their gradual cessation over 5 min of reperfusion. Generation of H2O2 in the myocardium in the first minutes of reperfusion was visualized by means of cerium cytochemistry and confirmed by X-ray microanalysis. The mechanism of the arrhythmogenic effect of FOR may involve inhibition of the sarcolemmal Na+/K+-ATPase, as demonstrated in the rat heart sarcolemmal fraction subjected to FOR-generating system (H2O2 + FeSO4).

MeSH terms

  • Animals
  • Arrhythmias, Cardiac / etiology
  • Arrhythmias, Cardiac / metabolism
  • Arrhythmias, Cardiac / physiopathology*
  • Cerium
  • Electrocardiography / drug effects
  • Electrophysiology
  • Free Radicals / metabolism
  • Histocytochemistry
  • Hydrogen Peroxide / metabolism
  • In Vitro Techniques
  • Kinetics
  • Microdialysis
  • Myocardial Reperfusion Injury / complications
  • Myocardial Reperfusion Injury / metabolism
  • Myocardial Reperfusion Injury / physiopathology*
  • Myocardium / enzymology
  • Myocardium / pathology
  • Oxidants / metabolism
  • Rats
  • Reactive Oxygen Species / metabolism
  • Reactive Oxygen Species / physiology*
  • Sarcolemma / enzymology
  • Sarcolemma / pathology
  • Sodium-Potassium-Exchanging ATPase / metabolism

Substances

  • Free Radicals
  • Oxidants
  • Reactive Oxygen Species
  • Cerium
  • Hydrogen Peroxide
  • Sodium-Potassium-Exchanging ATPase