A REVIEW ON PATHOLOGY OF MYOCARDIAL ISCHEMIA AND VARIOUS TYPES OF NOVEL BIOMARKERS

Ischemia can also be described as an inadequate flow of blood to a part of the body, caused by constriction or blockage of the blood vessels supplying it. Ischemia of heart muscle produces angina pectoris. Since oxygen is mainly bound to hemoglobin in red blood cells, insufficient blood supply causes tissue to become hypoxic, or, if no oxygen is supplied at all, anoxic. In very aerobic tissues such as heart and brain, at body temperature necrosis due to ischemia usually takes about 3-4 hours before becoming irreversible. This and typically some collateral circulation to the ischemic area accounts for the efficacy of "clot-buster" drugs such as Alteplase, given for stroke and heart attack within this time period. However, complete cessation of oxygenation of such organs for more than 20 minutes typically results in irreversible damage. In many cases, obstruction of the coronary artery by thrombus is minimal, resulting in little or no impairment to coronary flow. Alternatively, the thrombus can result in total occlusion of the artery with classic symptoms and ECG findings. The combination of reduced blood flow and increased oxygen demand precipitates the critical imbalance of oxygen supply and demand that leads to myocardial ischemia (i.e., unstable angina). Persistent ischemia can result in myocyte death, which may be detected using biomarkers of necrosis and forms the basis for the diagnosis of AM