Acute coronary syndrome and heart failure

Acute coronary syndrome describes a range of clinical conditions that arise from acute myocardial ischaemia and includes unstable angina, non-ST-segment elevation myocardial infarction (NSTEMI) and ST-segment elevation myocardial infarction (STEMI). It presents with chest pain, pressure, tightness, or heaviness that radiates to neck, jaw, shoulders, back, or one or both arms. Heart failure occurring in the environment of an acute coronary syndrome describes an inability of the heart to sustain adequate forward blood flow for metabolizing tissues. It may be a direct consequence of myocardial ischaemia or infarction with abnormal systolic function, or be secondary to acute valvular regurgitation or ventricular septal rupture. In its most severe form acute heart failure is termed cardiogenic shock. The priority of treatment in both conditions is to use ECG and biochemical cardiac markers to identify patients with STEMI who may benefit from immediate reperfusion therapy. In patients with STEMI, blood flow to the myocardium may be restored with thrombolytic therapy or percutaneous coronary intervention. Patients with unstable angina or NSTEMI require therapy to prevent progression to full-thickness myocardial infarction, with anti-platelet and anticoagulant medication and β-blockade. Patients who develop heart failure following myocardial ischaemia or infarction may be risk-stratified by measuring B-type natriuretic peptide. Once cardiogenic shock has developed the prognosis is poor, with an estimated mortality rate of 75%. Patients may require invasive monitoring, ventilatory support, cardiovascular support, or intra-aortic balloon counterpulsation.