Final answer:
NSTEMI, or non-ST elevation myocardial infarction, is a type of heart attack without the classical ST-segment elevation on an ECG. It is diagnosed by characteristic changes in other ECG parts and elevated levels of creatine kinase MB and cardiac troponin in the blood.
Step-by-step explanation:
NSTEMI stands for non-ST elevation myocardial infarction. It is a type of myocardial infarction that does not show the classic ST-segment elevation on an ECG that is typically associated with a full heart attack or STEMI. Instead, an NSTEMI involves changes in other parts of the ECG and is usually confirmed by blood markers. Tests such as echocardiography or cardiac magnetic resonance imaging can also be utilized.
Blood tests reveal elevated levels of creatine kinase MB and cardiac troponin, which indicate damage to cardiac muscle cells. These enzymes and proteins are released when myocardial cells die because blood flow is obstructed, typically by a blood clot or plaque. NSTEMI is one form of acute coronary syndrome, which represents a spectrum of conditions associated with sudden, reduced blood flow to the heart.