Myocardial infarction (MI) is defined as myocardial cell death (necrosis) due to prolonged ischemia. It is recognized by the presence of different proteins (cardiac biomarkers) in the blood that are released from the damaged myocytes. The best available biomarkers are cardiac Troponin I, cardiac Troponin T, CK-MB and Myoglobin.
Troponins are structural proteins that act to regulate cardiac muscle contraction. There are three isoforms: Troponin C, Troponin I and Troponin T. They are released into the bloodstream from injured muscle cells during cardiac ischemia. In contrast to Troponin C, the isoforms cTnI and cTnT are specific to cardiac muscles and do not overlap with skeletal muscles.