Reduced tolerance to digitalis-induced arrhythmias caused by coronary-flow alterations in isolated perfused heart of guinea pigs.
The ligation of a main branch of coronary vein elevates the sensitivity of isolated, perfused (Langendorff) preparations of guinea-pig heart to arrhythmogenic actions of digoxin. Retrograde perfusion studies indicate that the presence of an area with a high extracellular K+ concentration, adjacent to an area with normal K+ concentration and exposed to the glycoside, predisposes the heart to digitalis-induced toxicity. This model may be useful in studying the mechanism by which acute myocardial infarction decreases the therapeutic index of cardiac glycosides.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000503:physiopathology; D003326:Coronary Circulation / Q000187:drug effects*; D004077:Digoxin / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D009206:Myocardium / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium