Diagnosing Acute Coronary Syndrome

The classic symptom of acute coronary syndrome (ACS) is acute chest pain, usually localised behind the sternum or experienced over a more diffuse area, such as across the anterior chest. Pain from ACS often radiates to the left arm or to both arms, as well as to the shoulders, back, and jaw. Patients typically describe the pain as crushing, squeezing, pressing, or burning.^{51, 52} Women are more likely than men to present with symptoms other than chest pain. Such symptoms may include dyspnoea, nausea, vomiting, fatigue, indigestion, sweating, and pain localised in the arm or shoulder.⁵³

Initial diagnosis of ACS is based on patient history, electrocardiography, and measurement of blood levels of the cardiac biomarkers CK-MB and troponin. Levels of these biomarkers are elevated when there is myocardial injury. These studies help differentiate patients with ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) who need emergent revascularisation procedures from other patients with ACS for whom less aggressive intervention may be appropriate.^{51, 52}