[Myocardial infarction in the adult under 35 years of age].
Infarction in the adult aged less than 35 is almost always accompanied by risk factors, the most common of which are tobacco abuse, lipid disturbances, obesity, a strong family history of cardiovascular disease and, in the woman, the use of contraceptives. The coronary arteries are sometimes normal (10-15 p. cent) but coronary lesions are most often single vessel, proximal and affect the anterior interventricular branch. Actual coronary thrombosis probably plays a more important role than in the older adult. Ventricular function is often markedly impaired. The infarct is most often anterior, transmural and large in size, with ventricular arrhythmias more frequent and a higher risk of sudden death. Post-hospital complications are the same as in the older adult, with possibly less good results of aorto-coronary venous bypasses. Long term mortality depends directly upon the number of vessels affected, but is markedly better than in the older adult.