MYOCARDIAL infarction is a dramatic episode in the course of coronary artery disease, but it is often thought of in terms of a disease entity with its own course, prognosis and treatment. With the occurrence of myocardial infarction, a new factor is introduced into the course of coronary artery disease with myocardial ischemia, namely, gross and irreparable destruction of a portion of the cardiac muscle. This damage to the myocardium determines the immediate prognosis and the ultimate outcome entirely independently of the degree and progression of coronary arteriosclerosis. Thus, the size of the area of the destroyed muscle is one of the important factors in the prognosis, yet little investigative work has been done in estimation of the size of a myocardial infarct during life.
In terms of ordinary clinical thinking, a severe attack of pain with fully developed clinical signs of myocardial infarction is usually considered as evidence of