[1] The most common symptom is centrally located pressure-like chest pain, often radiating to the left shoulder[2] or angle of the jaw, and associated with nausea and sweating.

[3] Acute coronary syndrome is subdivided in three scenarios depending primarily on the presence of electrocardiogram (ECG) changes and blood test results (a change in cardiac biomarkers such as troponin levels):[4] ST elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (NSTEMI), or unstable angina.

[8] The cardinal symptom of critically decreased blood flow to the heart is chest pain, experienced as tightness, pressure, or burning.

[9] Localization is most commonly around or over the chest and may radiate or be located to the arm, shoulder, neck, back, upper abdomen, or jaw.

[11] Chest pain with features characteristic of cardiac origin (angina) can also be precipitated by profound anemia, brady- or tachycardia (excessively slow or rapid heart rate), low or high blood pressure, severe aortic valve stenosis (narrowing of the valve at the beginning of the aorta), pulmonary artery hypertension and a number of other conditions.

After the coronary arteries are unblocked, there is a risk of reperfusion injury due spreading inflammatory mediators throughout the body.

[20] After a ban on smoking in all enclosed public places was introduced in Scotland in March 2006, there was a 17% reduction in hospital admissions for acute coronary syndrome.

[21] People with presumed ACS are typically treated with aspirin, clopidogrel or ticagrelor, nitroglycerin, and, if the chest discomfort persists, morphine.

[23] If the ECG confirms changes suggestive of myocardial infarction (ST elevation in specific leads, a new left bundle branch block or a true posterior MI pattern), thrombolytics may be administered or percutaneous coronary intervention may be performed.

It was found that thrombolysis is more likely to be delivered within the established ACC guidelines among patients with STEMI as compared to PCI according to a 2009 case control study.

[26] If there is no evidence of ST segment elevation on the electrocardiogram, delaying urgent angioplasty until the next morning is not inferior to doing so immediately.

[28] Cocaine-associated ACS should be managed in a manner similar to other patients with acute coronary syndrome except beta blockers should not be used and benzodiazepines should be administered early.