The term unstable angina pectoris covers several forms of ischemic heart disease with heterogeneous pathophysiology, different clinical presentation and non-uniform prognosis. Recent results of angiographic, angioscopic and autoptic observations on the nature of unstable coronary plaque rendered possible a better understanding of clinical symptoms of the unstable myocardial ischemia. Holter ECG monitoring of patients with unstable angina pectoris showed, that myocardial ischemia may persist despite the medical control of angina pectoris. It seems therefore more appropriate to use the terms unstable myocardial ischemia or unstable coronary syndromes rather than unstable angina pectoris. Coronary angiography in patients with unstable angina pectoris demonstrated eccentric narrowing with irregular or overhanging edges or intraluminal filling defects in 71-73% of vessels responsible for unstable myocardial ischemia. Autoptic studies showed, that thrombus usually develops on plaque with fissures, ulcerations and hemorrhage. The common pathway for all unstable coronary syndromes is an impairment of plaque integrity with subsequent activation of platelets, development of thrombosis and coronary spasm. Subsequent fate of coronary thrombus determines the clinical course with ischemic episodes lasting from several minutes to several hours. Medical therapy, PTCA or coronary bypass surgery are used to stabilise the patient, however, myocardial infarction or sudden death may occur.

Keywords: Angina, Unstable /diagnostic imaging/; Coronary Angiography; Electrocardiography, Ambulatory; Humans