Myocardial infarction, or "heart attack," is irreversible damage to myocardial tissues caused by prolonged ischemia/hypoxia and by reperfusion-induced injury. The damaged tissue is initially composed of a necrotic core surrounded by a marginal (or border) zone that can recover or become irreversibly damaged. The border zone may be an important site of arrhythmogenesis. Collateral blood flow is an important determinant of infarct size and whether or not the border zone becomes irreversibly damaged.
Infarcted tissue does not contribute to tension generation during systole, and therefore can alter ventricular systolic and diastolic function and disrupt electrical activity. Long-term consequences include ventricular remodeling (e.g., development of compensatory hypertrophy), ventricular failure, arrhythmias and sudden death.
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