Acute myocardial infarction: a diagnosis based on cardiac troponinsĪ diagnosis of acute myocardial infarction (AMI) is made only after blood analyses confirm elevated levels of myocardial proteins. Flowchart showing the natural course of coronary artery disease and classification of acute coronary syndromes into STEMI, NSTEMI and unstable angina using ECG criteria. The reader should study this chart carefully. It also presents a classification of acute coronary syndromes and myocardial infarctions. Refer to Figure 1, which illustrates the natural course of coronary artery disease, from risk factors to acute coronary syndromes. Hence, the difference between STE-ACS and NSTE-ACS is merely the presence of ST segment elevations in the former. NSTEMI and unstable angina have similar pathophysiology and management are also similar. Patients with NSTE-ACS who do not develop infarction are classified as unstable angina (UA), which is an imminent precursor to myocardial infarction. Most patients with NSTE-ACS will develop acute myocardial infarction, which is then classified as NSTEMI (Non-ST Elevation Myocardial Infarction). coronary blood flow is not completely obstructed). NSTE-ACS typically presents with ST segment depressions and/or T-wave inversions. NSTE-ACS is caused by partial occlusion of the artery (i.e. This category includes all acute coronary syndromes without significant ST segment elevations on ECG. NSTE-ACS is the acronym for Non-ST Elevation Acute Coronary Syndrome. Moreover, STE-ACS is caused by a complete coronary artery occlusion and virtually all these patients will develop myocardial infarction, which is classified as STEMI (ST Elevation Myocardial Infarction). All acute coronary syndromes which exhibit significant ST segment elevations on ECG are classified as STE-ACS. STE-ACS is the acronym for ST Elevation Acute Coronary Syndrome.

In either case, the patient will experience severe chest pain due to the abrupt reduction of coronary blood flow. Acute coronary syndromes are subdivided into STE-ACS and NSTE-ACS. The occlusion may be complete or partial, depending on the size of the thrombus and the plaque itself. Such a thrombus will cause occlusion of the artery. Classification, diagnosis and definitions of acute coronary syndromes (ACS) and acute myocardial infarction (AMI)Īn acute coronary syndrome occurs when an atherosclerotic plaque disrupts, which results in the activation of thrombocytes and coagulation factors and ultimately the formation of a thrombus.

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