Post-traumatic myocardial infarction with hemorrhage and microvascular damage in a child with myocardial bridge: Is coronary anatomy actor or bystander?

We present the case of a 13 year old patient with myocardial bridge in left anterior descending coronary artery, who develops a myocardial infarction after a cardiothoracic trauma. About 24 hours after admission for trauma, an Electrocardiogram (ECG) showed an ST-segment elevation on anterior-lateral leads and QS complex referable to anterior-septal infarction, and an increase in troponin T serum levels was noted. An impaired left ventricular ejection fraction with diffuse regional wall motion abnormalities involving the left ventricular apex and interventricular septum were seen at transthoracic echocardiography. Contrast enhanced cardiac magnetic resonance showed a widespread myocardial edema and necrosis at the level of left ventricular apex and interventricular septum. Intramural hemorrhage and signs of microvascular damage were found mainly at the mid-ventricular level of the anteroseptal and anterior segments of myocardium. The coronary angiography revealed normal coronary arteries except for a myocardial bridge on distal part of left anterior descending coronary artery. A myocardial infarction with hemorrhage and microvascular damage was diagnosed, but the absence of a correspondence between site of the most severe myocardial injury and distal location of myocardial bridge was noted. Whether myocardial infarction and microvascular damage have been caused only by traumatic hit, or also by the contribution of myocardial bridge, is unknown. An intense constriction of left anterior descending coronary artery at the level of myocardial bridge could have determined thrombus formation with subsequent septal and distal embolization and myocardial infarction.