Relations between the energy state of the myocardium and release of some products of anaerobic metabolism during underperfusion.

The relations between parameters of cellular energy and the release of succinate, alanine and creatine from isolated, isovolumic guinea pig hearts were studied during underperfusion (0.2 ml/min) with glucose or acetate. The heart work index (the product of the left ventricular pressure and the heart rate), tissue ATP and phosphocreatine contents did not depend upon the nature of the substrate when coronary flow was 19 ml/min. However, 50 min underperfusion with acetate resulted in a twofold increase in diastolic pressure, while glucose prevented the development of contracture. A more rapid ATP depletion accompanied by an increased succinate and creatine release was observed during underperfusion with acetate as compared with glucose. Succinate and alanine accumulation in myocardial effluent was related to a decrease in tissue ATP, while creatine release showed a close, inverse correlation with the tissue phosphocreatine/creatine ratio. Hyperbolic and linear relations were found between these indices for glucose- and acetate-perfused hearts, respectively. The results suggest that the determination of succinate, creatine and alanine in myocardial effluent may be used for assessment of the energy status of the ischemic heart.