Assessment of cardiac energetics at the level of ATP-synthesis, chemomechanical energy transformation and whole organ dynamics as a function of haemodynamic load, ventricular configuration and oxygen- and substrates supply is basic to understanding cardiac function under physiological and pathophysiological (hypertrophy, hypoxia, ischaemia and heart failure) conditions. Moreover, cardiac energetics should be an important consideration in the choice and application of drugs especially in the case of vasodilators, inotropic agents and in cardioprotective measures. Only by considering energetics at the subcellular, cellular, and whole-heart level we can arrive at a better understanding of cardiac performance and ultimately better clinical judgement and drug therapy. Quantification of myocardial energetics will also help to determine the optimal time for surgical interventions such as valvular replacement or aneurysm resection. The present volume is the outcome of an international symposium on cardiac energetics held in Gargellen/Montafon (Austria), June 1986. The contributions will certainly help bridge the existing gap between basic research involving isolated structures and that involving the whole organ, on the one hand, and render the results derived from basic research applicable to clinical problems, on the other hand.