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

• In previous papers from this laboratory,' it has been shown that isolated guinea pig and cat hearts perfused with Tyrode solution without substrates undergo a decrease in rate, a decrease in amplitude of the R wave, a lengthening of the P-R interval, ventricular premature contractions, A-V dissociation, and, finally, ventricular fibrillation. The ventricular fibrillation, induced by the lack of substrates both in isolated guinea pig and cat hearts, does not revert spontaneously to normal or idioventricular rhythm. In guinea pig hearts, either glucose or butyrate reversed ventricular fibrillation induced by this procedure to normal or idioventricular rhythm. Tn contradistinction, the ventricular fibrillation of the isolated cat heart is not reversed by perfnsion with Tyrode solution containing glucose, fructose, galactose, butyrate, or pyruvate, nor is the contractile force increased by glucose and butyrate in the isolated hypodynamic cat heart.' 4