Aetiology and risk factors in young patients with recent acute myocardial infarction.

One hundred and forty-five young patients (aged 18-40 years) with acute myocardial infarction are reported. In 14 of these infarction was due to unusual cause of which infective endocarditis was the most common. One hundred of the patients underwent review of risk factors 2-4 months after infarction: 29% had a previous history of angina, 11% were hypertensive, 85% were smokers during the year before infarction and 5% were ex-smokers, while 31% had a family history of ischaemic heart disease among first-degree relatives and 27% were obese. Seventy-two per cent had serum cholesterol values of greater than 5,7 mmol/l, 63% had fasting serum triglyceride values of greater than 1,7 mmol/l and 29% were hyperuricaemic. Only 2% had none of the following major risk factors: serum cholesterol greater than 6,5 mmol/l, serum triglycerides greater than 1,7 mmol/l, a history of cigarette smoking, a history of hypertension or blood pressure greater than 160/95 mmHg. We conclude that there should be a high index of suspicion for unusual causes of acute myocardial infarction in patients in this age group and that one or more of the major risk factors are an almost invariable finding in patients with infarction of atheromatous origin.