[Classification of acute coronary syndromes]

The classification of acute coronary syndromes takes into account new data concerning pathophysiology and management. Acute coronary syndromes have a common substrate, namely rupture or erosion of an atherosclerotic plaque leading to thrombus formation and distal embolization, which is responsible for microinfarction with release of myocardial proteins (enzymes and troponins). In the context of acute chest pain, two different presentations of acute coronary syndromes are distinguished on the basis of electrocardiographic findings, according to wether or not there exist persistent ST-segment elevation. Acute coronary syndromes with permanent ST-elevation generally lead to Q-wave infarction and require urgent reperfusion. Acute coronary syndromes without permanent ST-elevation can be further subdivided into: non-Q-wave infarction, when there is release of markers of myocardial cell death, with a prognosis warranting aggressive medical therapy, early coronary angiography and revascularization whenever possible; unstable angina, in the absence of release of markers of cell death, with a more favourable prognosis allowing ambulatory management.