A transient, dose-dependent cardiac depression was produced by defibrillator shocks in an isolated, working canine heart preparation perfused with oxygenated arterial blood from a support dog. Accompanying this depression was an efflux of potassium (K+ ), forced out of the myocardial cells by the passage of defibrillating current. The transient increase in extracellular K + concentration was recorded graphically in the venous outflow. It was found that 5-msec rectangular wave shocks, from three to ten times defibrillatory current threshold, released doserelated pulses of K+ . We conclude that because extracellular K + is a myocardial depressant, at least part of the myocardial depression after defibrillation is caused by the release of K+ from the myocardial cells.
defibrillation, myocardial damage, toxicity, ventricular fibrillation, waveform
Date of this Version
Niebauer, M J.; Geddes, L A.; and Babbs, Charles F., "Potassium Efflux from Myocardial Cells Induced by Defibrillator Shock" (1986). Weldon School of Biomedical Engineering Faculty Publications. Paper 97.