Prevention of myocardial infarction.

The possible methods of preventing myocardial infarction have been discussed. The desirability of prevention in the total problem of myocardial infarction is stressed. The methods consist of the prevention of the underlying coronary atherosclerosis, and the secondary prevention of myocardial ischemia contributed by other factors than those presumed to relate to atherosclerosis. In the primary prevention of coronary atherosclerosis the two major risk factors are elevation of serum lipids and of blood pressure. The benefits to be achieved by reduction of elevation of both of these abnormalities are discussed. Both require a long-term approach starting as early in life as possible. The major methods of prevention or retardation of coronary ischemia irrespective of coronary artery disease involve discontinuance of cigarette-smoking and a program of increased physical activity. In addition, prevention or correction of polycythemia, anemia or hypercoagulability should be included. The use of oxygen, in higher percentage or at higher pressure than in the atmosphere, surgical intervention to improve the myocardial blood supply and pharmacologic agents to improve myocardial metabolism are also considered. Quantitation of the benefit of preventive programs is still impossible. Benefit from lowering blood lipids and blood pressure requires long-term therapy begun early in life. Discontinuance of cigarette smoking and increasing the amount of physical activity offer reasonable assurance of immediate benefit. So also does correction of hematologic abnormalities. Pharmacologic agents and surgery to improve coronary blood flow still require further evaluation.