by JULIEN IE HOFFMAN One of the earliest coronary physiologists was Scaramucci who, in 1695, postu­ lated that during systole the contracting myocardium inhibited coronary blood flow. Since then, the many contributions that have been made to our knowledge of the coronary circulation can be arbitrarily divided into three phases based on advances in technical methods. The early phase of research into the coronary circulation, done with great difficulty with crude methods, may be regarded as ending in the 1940s, and it included major discoveries made by such well known investigators as Georg von Anrep, Ernest Starling, Carl Wiggers, and Louis Katz, who formulated much of our basic understanding of the field. After 1940, the field of coronary physiology entered a new phase when instruments for high fidelity registration of coronary flow and pressure became available. This era was domi­ nated by Donald Gregg who combined careful attention to the function of these instruments (some of which he helped to develop) with an extraordinary ability to discern mechanisms from apparently minor changes in coronary flow and pressure patterns. His book 'The Coronary Circulation in Health and Disease' set a new standard in the field. After 1960, techniques for measuring regional myocardial blood flow became available, and enabled a large group of eminent investigators to make major advances in understanding the physiology and pathophysiology of myocardial blood flow.

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1 Basic coronary physiology.- 1.1 Introduction.- 1.1.1 Heart function and coronary flow.- 1.1.2 Control and extravascular resistance.- 1.1.3 Distribution of supply and demand.- 1.1.4 Mechanics, control and distribution in the coronary circulation.- 1.2 Coronary flow mechanics.- 1.2.1 Inhibition of coronary arterial flow during systole.- 1.2.2 Retrograde coronary arterial flow, venous flow and in-tramyocardial compliance.- 1.3 Regulation of coronary flow.- 1.3.1 Steady local control of coronary flow.- 1.3.2 How to define coronary tone?.- 1.3.3 Rate of adaptation of the coronary circulation to step changes in heart rate.- 1.3.4 Effect of perfusion pressure step.- 1.3.5 Reactive hyperemia.- 1.3.6 Mechanisms of coronary flow control.- 1.4 Heterogeneity in myocardial perfusion and oxygen supply.- 1.4.1 Distribution of flow from endocardium to epicardium.- 1.4.2 Heterogeneity induced by the arterial tree.- 1.4.3 Heterogeneity of oxygen supply/demand ratio.- 1.5 Relation between mechanics, control and distribution of coronary flow.- 1.6 Summary.- References.- 2 Structure and function of the coronary arterial tree.- 2.1 Basic anatomy.- 2.2 Collaterals.- 2.3 Structure of the coronary arterial tree.- 2.3.1 Ratios between diameters of mother and daughter branches.- 2.3.2 Growth of arterial cross-sectional area.- 2.3.3 Length distribution in the arterial tree.- 2.3.4 Arterial density applying symmetrical branching networks..- 2.4 Data on filling volume of the coronary arterial tree.- 2.5 Pressure distribution in the coronary arterial tree.- 2.6 Symmetrical, dichotomous branching network model.- 2.6.1 Definition of model structure.- 2.6.2 Prediction of volume.- 2.6.3 Prediction of pressure.- 2.7 Nonsymmetrical dichotomous branching network analysis.- 2.7.1 Strahler ordering.- 2.7.2 Fractal models.- 2.8 Discussion on structure and function of the arterial tree.- 2.9 Summary.- References.- 3 Structure and perfusion of the capillary bed.- 3.1 Structure of capillary bed.- 3.2 Capillary density and volume.- 3.3 Mechanical properties.- 3.4 Red cells in the capillary bed.- 3.4.1 Velocities.- 3.4.2 Red cell distribution at bifurcations.- 3.4.3 Hematocrit.- 3.5 Model of parallel and homogeneous perfused capillary bed.- 3.6 A model for the heterogeneous perfusion of the capillary bed.- 3.7 Capillary recruitment in the heart.- 3.8 Summary.- References.- 4 Structure and function of coronary venous system.- 4.1 Basic anatomy.- 4.2 Distribution of coronary venous flow.- 4.3 Flow and pressure waves in the epicardial veins.- 4.4 Waterfall behavior of coronary epicardial veins.- 4.5 Coronary venous compliance.- 4.6 Summary.- References.- 5 Linear system analysis applied to the coronary circulation.- 5.1 Definitions.- 5.1.1 System.- 5.1.2 Linearity.- 5.1.3 Time and frequency domains.- 5.1.4 Models.- 5.1.5 Load line analysis.- 5.2 Linear intramyocardial pump model.- 5.2.1 Interpretation of the coronary load lines.- 5.2.2 Intramyocardial pump and the right coronary artery.- 5.2.3 Shortcomings of the linear intramyocardial pump model.- 5.3 Load line analysis of collateral flow.- 5.4 Input impedance.- 5.4.1 Input impedance during long diastoles.- 5.4.2 Coronary impulse response in diastole and systole.- 5.4.3 Model interpretation of coronary input impedance.- 5.5 Nonlinear physical elements and linear system analysis.- 5.6 Discussions of the linear models of coronary circulation.- 5.7 Summary.- References.- 6 Interaction between contraction and coronary flow: Theory.- 6.1 Systolic extravascular resistance model.- 6.1.1 Basic behavior of extravascular resistance model.- 6.1.2 Discussion of extravascular resistance model.- 6.2 The waterfall model.- 6.2.1 Basic model behavior of the waterfall model.- 6.3 Nonlinear intramyocardial pump model.- 6.3.1 Pressure dependency of compartmental resistance.- 6.3.2 Steady state arterial pressure-flow relations during arrest.- 6.3.3 Solutions for the subendocardial model layer of the contracting myocardium.- 6.3.4 Compartmental volume variations.- 6.3.5 Flow simulations.- 6.4 Variable elastance model.- 6.4.1 Experimental support.- 6.4.2 Variable elastance concept.- 6.4.3 A mathematical intramyocardial pump model with time varying elastance as pump generator.- 6.5 Discussion.- 6.6 Summary.- References.- 7 Interaction between contraction and coronary flow: Experiment.- 7.1 Parallel shift of pressure-flow relations.- 7.2 Pressure dependency of coronary resistance.- 7.3 Effect of heart rate on microsphere distribution.- 7.4 Contractility and microsphere distribution.- 7.5 Intramyocardial compliance.- 7.6 Pulsations in coronary pressure at constant flow perfusion.- 7.7 Diastolic pressure-flow lines.- 7.8 Discussion.- 7.9 Summary.- References.- 8 Arteriolar mechanics and control of flow.- 8.1 Morphology of the arteriolar wall.- 8.2 Myogenic response.- 8.3 Arteriolar vasomotion.- 8.4 Strain and stress in the arteriolar wall.- 8.5 Myogenic responses in relation to autoregulation of flow.- 8.5.1 Relation between pressure and resistance with and without myogenic tone.- 8.5.2 Width of the autoregulatory plateau.- 8.5.3 The optimal strength of myogenic tone.- 8.6 Compliance of arterioles.- 8.6.1 Effect of tone on static compliance.- 8.6.2 Quasi-static distensibility of dilated coronary arteries.- 8.6.3 Frequency dependency of distensibility of active and passive small coronary arteries.- 8.7 Discussion.- 8.7.1 Vasodilation.- 8.7.2 Arterioles and regulation of flow.- 8.8 Summary.- References.- 9 Static and dynamic analysis of local control of coronary flow.- 9.1 Introduction.- 9.2 Steady state behavior of flow control.- 9.3 Characteristics of dynamic coronary flow control.- 9.3.1 Rate of change in flow adaptation.- 9.3.2 Rate of change of autoregulation.- 9.3.3 Summary of t50 values.- 9.4 Rate of change in myocardial oxygen Consumption.- 9.4.1 Model for the correction of changing oxygen buffers.- 9.4.2 Transients in oxygen consumption.- 9.5 Oxygen model of coronary flow control.- 9.5.1 Model definition and equations.- 9.5.2 Steady state solutions.- 9.5.3 Dynamic solutions of the oxygen model.- 9.5.4 Oxygen dose-response curves.- 9.6 Myocardial contraction and dynamics of coronary flow control.- 9.7 The directional effect in dynamic responses of autoregulation.- 9.8 Myogenic response in the coronary circulation.- 9.9 Adenosine model.- 9.9.1 Adenosine dose-response curves.- 9.9.2 Experimental evidence for and against the adenosine hypothesis.- 9.10 Discussion.- 9.10.1 Adaptation of coronary flow …