This patient has most likely suffered blunt cardiac injury (BCI), such as myocardial contusion, following a sternal fracture, resulting in ECG changes mimicking a myocardial infarction.
Blunt cardiac injury (BCI) is a poorly characterized disease with varied presentations and no clear diagnostic criteria. Injuries may include rupture of the ventricular or atrial wall, septum, or a valve; cardiac dysfunction; arrhythmia; or, rarely, myocardial infarction.
Standard ACLS protocols are used to manage severe arrhythmia; immediate surgical consultation is required for severe structural cardiac injury. Echocardiography and cardiology consultation are necessary for any patient with a complex arrhythmia, cardiac dysfunction, diastolic murmur (not known to be old), or signs of heart failure. Screening with serial ECGs, cardiac monitoring, and observation for 4-6 hours is sufficient in hemodynamically stable patients.
Crown and Hawkins review the diagnosis of nonstructural cardiac trauma. Cardiac dysrhythmias, including ventricular fibrillation and sudden cardiac arrest, can occur in both cardiac contusion and cardiac concussion (commotio cordis) and may be fatal. Continuous electrocardiographic monitoring, assessment of cardiac troponin I and transesophageal echocardiograms are important aids in the evaluation of cardiac contusion and concussion.
Nagy et al. studied the use of diagnostic testing in patients suspected of blunt cardiac trauma. A screening echocardiogram and cardiac biomarkers did NOT appear to add to the management of the hemodynamically stable patient without historical or clinical features suggestive of significant BCI, and the authors do not routinely obtain these tests.
Image A shows the ECG of a patient with blunt cardiac injury showing ST-segment changes.
Image B shows a lateral chest radiograph showing a fracture of the body of the sternum.
Image C shows a normal ECG.
Answers 1 and 2: While this patient's ECG does show ST-segment changes, the diagnosis of myocardial contusion is more likely in a patient with a sternal fracture.
Answer 4: Pericardial tamponade would not result in ST-segment changes and would cause muffled heart sounds, jugular venous distension, and low-voltage QRS complexes on EKG.
Answer 5: Tension pneumothorax would cause unilaterally absent breath sounds and jugular venous distension.
Crown LA, Hawkins W. Commotio cordis: clinical implications of blunt cardiac trauma. Am Fam Physician. 1997 May 15;55(7):2467-70.
PMID: 9166145 (Link to Abstract)
Nagy KK, Krosner SM, Roberts RR, Joseph KT, Smith RF, Barrett J. Determining which patients require evaluation for blunt cardiac injury following blunt chest trauma. World J Surg. 2001;25(1):108.
PMID: 11213149 (Link to Abstract)