ON THE ENERGY-RICH PHOSPHATE SUPPLY OF THE FAILING HEART

Abstract

Hearts of dog heart-lung prepns. failing spontaneously or as a result of the admn. of various general anesthetics or local anesthetics, or of mersalyl or quinacrine, have a normal supply of adenosine polyphosphate and are richer in phosphocreatine than non-failing hearts. Both non-failing and failing hearts contain only negligible amts. of acyl phosphate. The elevated phosphocreatine content of the failing hearts can probably be accounted for in part by a lowered rate of beat. The identity of the phosphate fraction detd. as the phosphate of phosphocreatine has been verified. In the heart of the heart-lung prepn., non-failing as well as failing, this fraction is considerably higher than in the heart in situ. Analysis of earlier and of the present data reveals a lack of good correlation between the amts. of phosphorylated and of total creatine in the heart of the heart-lung prepn. of the dog. The results indicate that the types of myocardial failure studied are due to impairment of the utilization and not of the generation of phosphate bond energy. The implication of this conclusion in regard to the mechanism of the positive inotropic cardiac action of certain pharmacologic agents is pointed out.