W. Bleifeld – Författare

W. KUPPER Coronary artery vasoconstriction is not only the mechanism responsible for Prinzmetal's variant angina, but may also be involved in stable angina pectoris and myocardial infarction. However, the underlying patho-physiological mecha- nisms and the importance of coronary vasoconstriction in these syndromes is still largely unknown. Several hypotheses have been proposed. Sympathetic nervous activity plays a key role in the regulation of coronary blood flow, but mechanical or humoral constrictive factors may be active as well. a-adrenergic tone Adrenergic nerve fibers accompany coronary vessels of any size. The stimulation of cardiac sympathetic nerves causes an increase in coronary blood flow. If, however, chronotropic and inotropic effects of adrenergic stimulation are sup- pressed pharmacologically by beta-adrenoceptor blockade, a reduction in flow is observed. Thus, the primary effect of sympathetic stimulation on the coronary arteries is the alpha-adrenergic mediated vasoconstriction. Functionally inner- vated alpha-adrenoceptors have been documented both in large coronary con- ductance arteries and in the small resistance vessels.Animal studies and a human study have documented that a permanent constrictor tone is present on the coronary circulation both at rest and during exercise; this condition could be prevented with alpha-adrenoceptor blockade or was absent after heart transplan- tation. Therefore, alpha-adrenoceptor mediated coronary constriction is an at- tractive hypothesis as a possible pathophysiological mechanism of inappropriate coronary vasoconstriction and cororiary vasospasm.

Echocardiography has recently become one of' the most important techniques in clinical cardiology. The major advantage of this method is its noninvasive nature enabling us to apply it under a widespread variety of clinical conditions. In the late 1960s, when research and clinical application of echo cardiography were started, and during the first decade investigations were mainly focused on the morphology of the valves and the chambers of the heart. The introduction of two-dimensional echocardiography was a major breakthrough in visualizing different portions of the heart. How­ ever, the poor resolution of the first devices provided only little qualitative information. With the introduction of phased array 2-D-echo-devices yielding better results and the application of computer techniques for the processing of M-mode and two-dimensional echo cardiograms, a great amount of qualitative information has become available to describe not only the morphology, but also the dynamic function of the heart in a noninvasive manner. This volume summarizes the lectures held at the International Symposium on Echocardiography, Hamburg, September 1978, endeavoring to review the current state of knowledge with regard to echo cardiography in the experimental and clinical setting. We herewith thank all lecturers, who have contributed to the publication and the Pharma-Schwarz Company which enabled us to organize this meeting by a generous subsidy.

W. KUPPER Coronary artery vasoconstriction is not only the mechanism responsible for Prinzmetal's variant angina, but may also be involved in stable angina pectoris and myocardial infarction. However, the underlying patho-physiological mecha- nisms and the importance of coronary vasoconstriction in these syndromes is still largely unknown. Several hypotheses have been proposed. Sympathetic nervous activity plays a key role in the regulation of coronary blood flow, but mechanical or humoral constrictive factors may be active as well. a-adrenergic tone Adrenergic nerve fibers accompany coronary vessels of any size. The stimulation of cardiac sympathetic nerves causes an increase in coronary blood flow. If, however, chronotropic and inotropic effects of adrenergic stimulation are sup- pressed pharmacologically by beta-adrenoceptor blockade, a reduction in flow is observed. Thus, the primary effect of sympathetic stimulation on the coronary arteries is the alpha-adrenergic mediated vasoconstriction. Functionally inner- vated alpha-adrenoceptors have been documented both in large coronary con- ductance arteries and in the small resistance vessels.Animal studies and a human study have documented that a permanent constrictor tone is present on the coronary circulation both at rest and during exercise; this condition could be prevented with alpha-adrenoceptor blockade or was absent after heart transplan- tation. Therefore, alpha-adrenoceptor mediated coronary constriction is an at- tractive hypothesis as a possible pathophysiological mechanism of inappropriate coronary vasoconstriction and cororiary vasospasm.