Abnormal coronary vasomotion in ischemic heart disease.

Myocardial ischemia has long been thought to be caused by only critical arteriosclerotic plaques, which are the most obvious single denominators of ischemic cardiac syndromes. The author argues that just because other transient and dynamic mechanisms are more elusive than atherosclerotic plaques, we should not presume them to be unimportant. He reviews the work of his group and others, which suggests that dilation and constriction can occur at the site of coronary artery stenoses and in distal coronary vessels. Clinical and angiographic findings and the possible pathophysiological causes of vasomotor dysfunction that may modulate residual coronary flow in patients with chronic stable, unstable, and variant angina, and syndrome X are reviewed. Only when these mechanisms are more fully understood will it be possible to develop specific therapy.