Influence of K-Strophanthosid on Elasticity of the Tortoise Ventricle

Abstract

Summary

The cardiac glucoside K-Strophanthosid has no effect on the diastolic elasticity of tortoise ventricle with doses and within times which result in very large increases in tension set up and work done. Larger doses produce after a time great increases in diastolic elasticity, up to the point of contracture, but when such increases occur the work and tension production fall off. The increase in work capacity of tortoise ventricular muscle produced by this glucoside is not positively correlated with diastolic elasticity changes.

Inferences from observations on the failing mammalian heart are confused by the fact that anoxia itself alters elasticity, and therefore the increased efficiency produced by digitalis would in itself be expected to increase diastolic elasticity. Such an indirect effect is a secondary result of the primary action of the drug upon work performance.