Effects of adenosinetriphosphate and potassium chloride on ventricular fibrillation induced by lack of substrates.

Abstract

The perfusion of the isolated guinea pig or cat heart with a substrate-free Tyrode solution induces a decrease in rate, a lengthening of the P-R interval, a decreased amplitude of the R wave, ventricular premature contractions, A-V dissociation, insignificant changes of the Q-T interval, and, finally, ventricular fibrillation with a regular atrial rhythm. In isolated hearts of both species, the reversal of ventricular fibrillation induced by lack of metabolites was attempted as follows: in guinea pig hearts, increasing the potassium chloride concentration of the Tyrode solution without glucose to 5.4 mM/L. reversed ventricular fibrillation in all cases. Adenosinetriphosphate (ATP) reversed this arrhythmia in only two of seven cases. However, in the isolated cat heart, potassium chloride in the same concentration (5.4 mM/L.) reversed ventricular fibrillation only in three out of seven cases. ATP did not reverse ventricular fibrillation in any cases, but potassium given with ATP reversed this arrhythmia in two out of four cases. In the cat heart, the reversal of ventricular fibrillation in all cases was accomplished only by increasing potassium chloride concentration to 5.4 mM/L. and adding glucose (1 Gm./L.).