Cardiac injury occurs when there is disruption of normal cardiac myocyte membrane integrity. This results in the loss into the extracellular space (including blood) of intracellular constituents including detectable levels of a variety of biologically active cytosolic and structural proteins, referred to as biomarkers, such as troponin, creatine kinase, myoglobin, heart-type fatty acid binding protein, and lactate dehydrogenase. Injury is usually considered irreversible (cell death), but definitive proof that cell death is an inevitable consequence of the process is not available.
When a sufficient number of myocytes have died (myocyte necrosis) or lost function, acute clinical disease is apparent. Ischemia, with or without infarction, consequent to an imbalance between the supply and demand of oxygen (and nutrients) is the most common cause of cardiac injury. Other causes include trauma, toxins, and viral infection.
The biochemical characteristics and utility of troponins, the diagnosis of cardiac injury, and acute myocardial infarction (MI) in particular will be reviewed here. The other biomarkers of cardiac injury and disease states, other than an acute MI, in which elevation of biomarkers are seen are discussed separately.
Read more: Troponins as cardiac injury markers
Source: sciencsnutshell
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