 Non-ST segment elevation myocardial infarction NSTEMI is one type of heart attack. It is defined as the development of heart muscle necrosis results from an acute interruption of blood supply to a part of the heart which is demonstrated by an elevation of cardiac markers Creatinine Kinase Isoenzyme MuscleBrain Type CK-MB in the blood and the absence of ST-segment elevation in ECG electrocardiography. ST-segment is a portion of ECG, its elevation indicates full thickness damage of heart muscle. Absence of ST-segment elevation in NSTEMI indicates partial thickness damage of heart muscle occurs. Therefore, NSTEMI is less severe type of heart attack compared to STEMI ST-segment elevation myocardial infarction in which full thickness damage of heart muscle occurs. 