急性冠脉综合征--正确诊断和治疗—培训课件.ppt

* * Slide 3 In patients with chronic stable angina pectoris, blood flow to the myocardium is reduced as a result of stenoses in one or more coronary arteries. These stenoses result from stable atherosclerotic plaques that encroach upon the lumen. When the patient is at rest, myocardial oxygen supply usually meets demand. If myocardial oxygen consumption increases significantly, however, myocardial ischemia and angina can occur in patients who have a critical degree of coronary stenosis; this angina is usually relieved by rest. By contrast, in the majority of patients with acute coronary syndromes, there is an acute increase in coronary obstruction. This may occur at rest, and is due to rupture of an unstable fibrous plaque covering an atheroma with consequent platelet adhesion [1]. Reference 1. Braunwald E et al. J Am Coll Cardiol 2000;36:970–1062. * Acute Coronary Syndrome is a term that refers to a group of clinical conditions that are defined by acute myocardial ischemia and associated with an increased risk of subsequent MI and cardiovascular death ACS includes the following conditions: Unstable Angina (UA) is defined as chest pain lasting greater than 20 minutes that is not relieved by rest. The pain generally appears unexpectedly and usually increases in frequency or intensity over time. Compared to stable angina, chest pain with unstable angina is usually more severe and prolonged. Patients with unstable angina have no evidence of cardiac tissue death Non-ST Segment Elevation Myocardial Infarction (NSTEMI) is defined as a myocardial infarction in which the patient’s electrocardiogram (ECG) reading shows no elevation of the ST segment. Patients will complain of chest pain and will have elevation of cardiac markers in their bloodstream. This elevation in cardiac markers, which reflects damage to the heart, differentiates an unstable angina patient from a patient with a NSTEMI. Although the arterial blockage may not be complete with a NSTEMI, it is