Given how serious coronary pathologies can be, any chest pain must automatically be considered as an acute coronary syndrome. This single term covers acute coronary syndromes with elevation of the ST segment, conventionally called STEMI. They have to be treated as emergencies for diagnosis and treatment. Reperfusion by thrombolysis or angioplasty is carried out without delay in the framework defined by the recommendations. The survival and functional prognosis of the patient depend on how quickly reperfusion is started and how successful it is. Acute coronary syndromes without ST segment elevation are called NSTEMI. They are only rarely considered as emergency cases for angioplasty. The diagnosis, which may sometimes be difficult, is based on hospital monitoring of the electrocardiogram, repeated troponin tests, and the patient's clinical context (prior coronary revascularization, renal failure, diabetes ...). Depending on tropinin levels, NSTEMI are divided into tropinin+ NSTEMI (with raised tropinin levels) and tropinin- NSTEMI (without raised tropinin level). Treatment for acute coronary syndromes, ST+ and NST (with confirmed or highly probable coronary origin), should initially include an association of antiplatelet and anticoagulant treatment, which will be continued if the coronary origin is confirmed. The long-term prognosis for the patient will be largely dependent on education and the control of cardiovascular risk factors. Acute coronary syndrome (ACS) groups together all the clinical manifestations previously subdivided into myocardial infarction, (transmural or rudimentary) and various categories of unstable angina manifestations.