Traumatic transection of the posterior descending coronary artery
The initial electrocardiogram (EKG) showed sinus rhythm with ST elevation in leads II, III, aVf, V5, and V6 (Fig. 1). Laboratory results were as follows: hemoglobin, 121 g/L; serum troponin, I 2.6 μg/L; and serum creatinine kinase MB, 13.4 U/L. A chest computed tomography (CT) scan showed a 2-cm hematoma in the lower portion of the anterior mediastinum, a mild noncompressive pericardial effusion (1 cm), and a mild left pleural effusion. There were contusion signs suggestive of a mild hepatic laceration. A left-sided chest tube was inserted with no significant drainage noted (<200 mL). The patient was resuscitated with a 1-L bolus of normal saline.
The patient was admitted to the intensive care unit (ICU). She was hemodynamically stable. Overnight, serum troponin levels increased to 10.9 μg/L (vs. 2.6 μg/L on admission), and a transthoracic echocardiogram demonstrated a mild pericardial effusion without signs of cardiac compression. The left ventricular ejection fraction was estimated at 55% with diffuse hypokinesia. Due to the increase in markers of cardiac injury and the presence of ST changes on the initial EKG, the decision was made to perform a coronary angiogram. This showed complete transection and thrombosis of the distal posterior descending coronary artery (Fig. 2).