Acute coronary syndrome (ACS) is caused by an acute underperfusion of the myocardium. ACS includes ST-elevation infarction (STEMI) and non-ST-elevation infarction (NSTEMI) as well as unstable angina pectoris. Causes of ACS are usually vulnerable atherosclerotic plaques, which lead to coronary thromboses through plaque erosions or ruptures. Clinically, ACS typically manifests as pectoral angina pain, often associated with sweating and nausea. Only a myocardial injury with signs of myocardial ischemia is referred to as a myocardial infarction (MI). The distinction between STEMI and non-ST-elevation-ACS (NSTE-ACS) is of great importance for acute therapy: Whereas STEMI requires a rapid invasive coronary diagnosis and reperfusion, the management of NSTE-ACS depends on the patient’s risk profile. All ACS patients require a permanent antithrombotic therapy, which begins with a year long dual platelet inhibition. In addition, high-dose statins are used for LDL reduction and β-blockers for cardioprotection.