[Traumatic myocardial infarction. Apropos of 2 cases]

Two cases of anterior transmural myocardial infarction occurring after closed chest injuries in young adults (26 and 29 years) are reported. In one case, the infarct was detected after 42 days when the patient gradually developed left ventricular failure after thoracic injury (fracture of the left 9th rib). In the other case, the diagnosis was made during the initial evaluation of a patient with multiple injuries by routine electrocardiography. Radio-isotopic investigations showed an antero-septo-apical and lateral defect with akinetic wall motion in the first case, and apical hypofixation with limited akinesis in the second one. Coronary angiography with left ventriculography was performed after 2 and 3 months respectively, and showed a prolonged non-atheromatous stenosis of the proximal left anterior descending artery with anterior wall hypokinesia, apical akinesia and mitral incompetence (Case n 1) and slight changes of the distal part of the left anterior descending artery with apical hypokinesia (Case n 2). These two cases bring the number of documented reported cases to 37 and illustrate the two possible mechanisms of myocardial infarction after closed chest trauma: direct trauma to the coronary arteries with vascular lesions and secondary myocardial infarction associated with a poor prognosis, and myocardial contusion resulting in random myocardial lesions which usually carry a better prognosis.