Context

Acute Coronary Syndromes (ACS) encompass a broad range of presentations including unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI) and ST-segment elevation myocardial infarction (STEMI). Understanding the pathophysiology, classification and clinical presentation of ACS is a pre-requisite for effective risk stratification and treatment. The chart shows the classification of ACS.

Myocardial infarction (MI) is defined pathologically as myocardial cell death following prolonged ischaemia [1]. In the context of cardiac marker rise, ST-segment changes on the ECG will define either STEMI or NSTEMI. At the time of presentation, however, cardiac marker status is unknown and classification of patients presenting with ischaemic chest pain is based largely on the ECG. Most patients with ST elevation progress to STEMI; their management is the subject of a separate Learning Session.

Many patients without ST elevation may not have a subsequent cardiac marker rise and are collectively termed non-ST-segment elevation acute coronary syndromes (ACS) at presentation; subsequently, their markers will define them as non-STEMI (marker rise) or UA (no marker rise) [2]. Risk stratification and management of ACS is the subject of this session.