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."

Few diagnostic methods in Cardiology have heralded such revolutionary developments as the introduction of coronary arteriography. When, in the early 1960's, Dr. F. Mason Sones demonstrated that visualization of the coronary anatomy in living humans was not only feasible but sufficiently safe and reliable to be used as a clinical tool in the evaluation of patients with known or suspected ischemic heart disease, the thus far somewhat neglected area of coronary circulation became the focus of interest. Naturally, for a considerable period of time a great deal of emphasis was placed upon coronary anatomy. Simple relations between narrowing lesions, impediment to flow, and prognosis were assumed to exist. Spectacular results of surgical coronary revascularization seemed to confirm this concept. Gradually it has become evident that the pathophysiology of coronary artery disease is considerably more complex. Diagnostic methods were introduced to assess and quantify exercise-induced myocardial ischemia. At first, these tests were used mainly to achieve a more discriminative selection of candidates for coronary arteriography and the coronary arteriogram remained the gold standard. Currently, these techniques have evolved to the point where they provide valuable functional and metabolic information. They have become powerful independent tools in clinical investigations and evaluation of individual patients.

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."