A 57-year-old male patient with an unknown medical history was brought into the emergency department after sustaining a gunshot (unknown caliber) wound to his left chest. The wound was allegedly self-inflicted, with the entry point at the left upper sternal border and the exit point near the tip of the left scapula. He was found unresponsive at home and was orotracheally intubated en route to the hospital. On initial examination, the patient had a temperature of 98.3°F, BP of 130/80 mm Hg, heart rate of 110 beats/min, and a ventilation rate of 16 breaths/min. Cardiopulmonary examination revealed the presence of bilateral breath sounds and a regular heart rhythm without any abnormal sounds. The skin was warm, dry, and without cyanosis or telangiectasias. There was no clubbing of the digits. The CBC count was notable for a WBC count of 37,000 cells/μL (neutrophils, 77%; bands, 4%) and a hemoglobin concentration of 10.5 g/dL, with an hematocrit of 31%. The total creatine kinase concentration was 266 U/L (normal range, 0 to 160 U/L), with an MB fraction of 32 U/L (normal range, 0 to 24 U/L) and a creatine kinase index of 12.0 (normal range, 0 to 6). The troponin-I level was 35 ng/mL (normal range, 0.0 to 1.9). Arterial blood gas measurements revealed a pH of 7.32, a Pco2 of 39 mm Hg, a Po2 of 53 mm Hg, and an O2 saturation of 88% on a fraction of inspired oxygen of 100% delivered by mechanical ventilation with no positive end-expiratory pressure. An ECG showed sinus tachycardia, left atrial enlargement, incomplete right bundle-branch block and poor R-wave progression. The results of an emergency department TTE, performed to rule out cardiac trauma, were unremarkable, except for a hyperdynamic left ventricle. No wall motion abnormality or pericardial effusion were noted. A chest radiograph showed a left-sided infiltrate without cardiomegaly (Fig 1
, left, A).