Effect of strophanthus on coronary blood flow and cardiac oxygen consumption of normal and failing human hearts.

The action of strophanthus preparations on the coronary blood flow and the oxidative metabolism of the normal and failing human heart has been studied by coronary sinus catheterization. It has been found that strophanthus preparations have no effect on the coronary flow or oxidative metabolism of either the normal or failing heart. This agrees with the concept that the oxidative metabolism (energy production) of the failing heart in vivo is not abnormal. The results indicate that this drug is responsible forcausing more effective conversion of oxidative energy into wvork. T HE EFFECT of various digitalis preparations on the circulation of patients with and without cardiac failure has been studied by a large series of investigators.'-' Quantitative measurements of the effect of digitalis on cardiac oxygen consumption and efficiency of the human heart in vivo have not been published to date because of difficulties in the methods involved. Catheterization of the coronary sinus in man in conjunction with the nitrous oxide method has now made it possible to determine cardiac oxygen consumption and coronary blood flow in man,'0 and to study quantitatively the effect of digitalis on the energy metabolism of the normal and failing human heart in vivo. This report deals with the effect of strophanthus preparations on the coronary blood flow and cardiac oxygen consumption of patients w,ith and without cardiac failure.