Unstable angina (UA), acute non-ST elevation myocardial infarction (NSTEMI), and acute ST elevation myocardial infarction (STEMI) are the three presentations of acute coronary syndromes (ACS). The first step in the management of patients with ACS is prompt recognition, since the beneficial effects of therapy are greatest when performed soon after hospital presentation. For patients presenting to the emergency department with chest pain suspicious of an ACS, the diagnosis of MI can be confirmed by the electrocardiogram and serum cardiac biomarker elevation; the history is relied upon heavily to make the diagnosis of unstable angina. (See "Criteria for the diagnosis of acute myocardial infarction" and "Initial evaluation and management of suspected acute coronary syndrome in the emergency department".)
Once the diagnosis of either UA or an acute NSTEMI is made, the acute management of the patient involves the simultaneous achievement of several goals:
●Relief of ischemic pain (see 'Initial medical therapy' below)
●Assessment of the patient's hemodynamic status and correction of abnormalities. Hypertension and tachycardia, both of which will markedly increase myocardial oxygen consumption requirements, may be managed with beta blockers and intravenous nitroglycerin.
●Estimation of risk (see 'Early risk stratification' below)