Main description:

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.

Contents:

I. Cardiac energetics as related to basic mechanisms and mechanical conditions.- The mechanism of muscle contraction. Biochemical, mechanical, and structural approaches to elucidate cross-bridge action in muscle.- Energetics studies of muscles of different types.- High energy phosphate of the myocardium: Concentration versus free energy change.- Cardiac basal and activation metabolism.- Mechanical determinants of myocardial energy turnover.- Cardiac energetics and the Fenn effect.- Cardiac energetics: significance of mitochondria.- Heat production and oxygen consumption following contraction of isolated rabbit papillary muscle at 20 DegreesC.- Regulation of heart creatine kinase.- Effect of creatine depletion on myocardial mechanics.- ATPase activity of intact single muscle fibres of Xenopus laevis is related to the rate of force redevelopment after rapid shortening.- II. Cardiac energetics as related to ontogenesis, chronic myocardial transformation and inotropic interventions.- Developmental differences in myocardial ATP metabolism.- The effects of acute and chronic inotropic interventions on tension independent heat of rabbit papillary muscle.- Chronic cardiac reactions. I. Assessment of ventricular and myocardial work capacity in the hypertrophied and dilated ventricle.- Chronic cardiac reactions. II. Mechanical and energetic consequences of myocardial transformation versus ventricular dilatation in the chronically pressure-loaded heart.- Chronic cardiac reactions. III. Factors involved in the development of structural dilatation.- Chronic cardiac reactions. IV. Effect of drugs and altered functional loads on cardiac energetics as inferred from myofibrillar ATPase and the myosin isoenzyme population.- Ca-independent regulation of cardiac myosin.- Implications of myocardial transformation for cardiac energetics.- Myocardial energetics and diastolic dimensions of the heart in experimental hypertension.- Myocardial contractility and left ventricular myosin isoenzyme pattern in cardiac hypertrophy due to chronic volume overload.- Decreased L-carnitine transport in mechanically overloaded rat hearts.- New aspects of excitation-contraction coupling in cardiac muscle: Two types of Ca++ entry promotion with and without involvement of cyclic AMP and Mg++ ions.- Energetic aspects of inotropic interventions in rat myocardium.- III. Cardiac energetics in hypoxia and ischaemia.- Mechanics of rat myocardium revisited: Investigations of ultra-thin cardiac muscles under high energy demand.- Changes in myocardial distensibility in rat papillary muscle: Fibrosis, KCl contracture, hypoxic contracture, oxygen and glucose deficiency contracture, and experimental tetanus.- Ultrastructural observations on the effects of different substrates on ischaemic contracture in global subtotal ischaemia in the rat heart.- Diastolic relaxation abnormalities during ischaemia and their association with high energy phosphate depletion, intracellular pH and myocardial blood flow.- Inotropic changes in ischaemic and non-ischaemic myocardium and arrhythmias within the first 120 minutes of coronary occlusion in pigs.- Phosphocreatine and adeninenucleotides in postasphyxial hearts with normal basal function and normal oxygen demand.- Changes in cardiovascular adrenoceptor response in rats subsequent to myocardial infarction.- Cardioprotection by anti-ischaemic and cytoprotective drugs.- Myocardial protection by antioxidant during permanent and temporary coronary occlusion in dogs.- Promising reduction of ventricular fibrillation in experimentally induced heart infarction by antioxidant therapy.- IV. Cardiac energetics in human heart: Clinical implications.- Atrial and ventricular isomyosin composition in patients with different forms of cardiac hypertrophy.- Heterogeneous regulatory changes in cell surface membrane receptors coupled to a positive inotropic response in the failing human heart.- Acute and chronic changes of myocardial energetics in the mammalian and human heart.- Cardiac energetics in clinical heart disease.- Influence of phosphodiesterase inhibition on myocardial energetics in dilative cardiomyopathy.- Predicting postoperative haemodynamics in valve patients.