Free oxygen radicals contribute to high incidence of reperfusion-induced arrhythmias in isolated rat heart.
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).
Ravingerová
T
T
Institute for Heart Research, Slovak Academy of Sciences, Bratislava.
Slezák
J
J
Tribulová
N
N
Dzurba
A
A
Uhrík
B
B
Ziegelhöffer
A
A
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D002563:Cerium; D004562:Electrocardiography / Q000187:drug effects; D004594:Electrophysiology; D005609:Free Radicals / Q000378:metabolism; D006651:Histocytochemistry; D006861:Hydrogen Peroxide / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D017551:Microdialysis; D015428:Myocardial Reperfusion Injury / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D009206:Myocardium / Q000201:enzymology / Q000473:pathology; D016877:Oxidants / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000502:physiology*; D012508:Sarcolemma / Q000201:enzymology / Q000473:pathology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D005609:Free Radicals; D016877:Oxidants; D017382:Reactive Oxygen Species; D002563:Cerium; D006861:Hydrogen Peroxide; D000254:Sodium-Potassium-Exchanging ATPase