[Secondary prevention of myocardial infarct with beta blockers]

At the present time, the mortality during the first year following an acute myocardial infarction is in the order of 10%. It subsequently drops to 4 or 5% per year. In more than one half of cases, the death of a postinfarct patient is sudden, with the major cause being ventricular fibrillation. These patients are also threatened by another risk: recurrent infarction. For Kannel, its incidence is 13% in men and 40% in women within 5 years of the first infarct. Its mortality is higher than that of the first infarct. Beta-blockers and calcium blockers reduce the myocardial oxygen consumption by a variety of mechanisms: beta-blockers block the beta-adrenergic receptors and calcium blockers inhibit the entry of calcium into the myocardial cells. Apart from their action on the process of excitation-contraction of myocardial fibres, the calcium blockers have also an action on the coronary vessels where they suppress or prevent spasm, and on peripheral arteries, where they cause vasodilatation thereby reducing the left ventricular afterload. The anti-ischaemic activity of these molecules is demonstrated by the reduction or elimination of angina, by the improved cardiac performance during stress test and by myocardial isotopic scans. The beta-blockers have other beneficial effects, in particular, antiarrhythmic and antiplatelet aggregation related to the neutralisation of catecholamines. Their antihypertensive action is also useful in coronary patients.(ABSTRACT TRUNCATED AT 250 WORDS)