Acute Coronary Syndrome and ST Segment Monitoring.

Acute coronary syndrome (ACS) is caused by a critical obstruction of a coronary artery because of atherosclerotic coronary artery disease. Three specific conditions are included: ST elevation myocardial infarction, non-ST elevation myocardial infarction, and unstable angina. The ST segment on the electrocardiogram is a sensitive and specific marker of myocardial ischemia and infarction; however, ST segment deviation is regional not global, thus the ECG lead must be placed over the affected region of the myocardium. This article describes ACS and infarction and the use of ST segment monitoring to detect these conditions.