A Case Report Of Myocardial Infarction From A Gunshot Wound To The Chest

SESSION TITLE: Medical Student/Resident Cardiovascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Acute myocardial infarction (AMI) following penetrating trauma without direct cardiac injury is sparsely reported. We report a 28-year-old male who presented with a single gunshot wound (GSW) to the chest who developed an AMI shortly after presentation. CASE PRESENTATION: A 28-year-old male, with no known medical history or cardiovascular risk factors, presented after a single GSW to the left chest. He was hemodynamically stable with mild tachycardia. Breath sounds were reduced in the left hemithorax. A non-sucking 1 cm wound was noted anteriorly in the third intercostal space medial to the midclavicular line, and a 1 cm wound was noted on the posterior chest wall in the midscapular region. Chest x ray confirmed hemothorax and a chest tube was inserted into the left pleural space, returning 850cc of blood. Chest computed tomography with angiography showed only lung and bony injury. There was no mediastinal, vascular, or gross cardiac injury. EKG revealed sinus rhythm with extensive anterior infarct. Troponins were mildly elevated at 0.09 ng/mL initially, but peaked at 200 ng/mL within 12 hours. Echocardiogram revealed ejection fraction (EF) of 50-55%, apical akinesis, and extensive hypokinesis. A pericardial effusion of 1.19cm was noted without tamponade. Repeat EKG after 12 hours, showed lateral infarct, acute anteroseptal infarct, and right axis deviation. Cardiac catheterization, with intravascular ultrasound, revealed a 100% occlusion at the proximal left anterior descending artery due to intramural hematoma. No evidence of atherosclerotic disease. Thrombectomy was attempted with little success. A drug eluting stent was then placed with excellent angiographic results. The patient was placed on beta blockers, diuretics, antiplatelets, and ACE inhibitors. DISCUSSION: AMI following penetrating chest trauma without evidence of direct cardiac or vascular injury is a very rare phenomenon. The pathophysiology is not well understood, but is presumed that the energy dispersion of the bullet is central to the development of intimal injury leading to intramural thrombus. CONCLUSIONS: Though uncommon, AMI is a sequela of penetrating chest injury. Suggested mechanisms of this injury include shockwave and cavitation resulting from energy dispersion from the bullet leading to coronary occlusion, laceration, dissection, or aneurysm formation. Our case highlights the possibility of such injury transmitting enough energy to result in intimal damage to the coronary vasculature, leading to thrombus formation. Cardiac evaluation and monitoring are crucial in chest GSW patients for early detection of AMI so there can be early intervention to preserve cardiac tissue. Reference #1: Reade Michael, Thomas Peter. (2016). Pathophysiology of ballistic trauma. 10.1093/med/9780199600830.003.0339 Reference #2: Gary J Ordog, Jonathan Wasserberger, Subramanian Balasubramanium (1984). Wound ballistics: theory and practice, Ann Emerg Med. 1984 Dec;13(12):1113-22. PMID: 6507972 DOI: 10.1016/s0196-0644(84)80336-4 Reference #3: Bock, Jeremy & Benitez, R. (2012). Blunt Cardiac Injury. Cardiology clinics. 30. 545-55. 10.1016/j.ccl.2012.07.001. DISCLOSURES: No relevant relationships by Olanrewaju Eletta, source=Web Response No relevant relationships by Marin Marinov, source=Web Response No relevant relationships by Marcus Stammen, source=Web Response No relevant relationships by Amy Stewart, source=Web Response