NREMT Paramedic Cognitive ExamTraumaMedium
A 22-year-old male is found unconscious after being struck in the chest with a baseball bat. He is unresponsive, apneic, and pulseless. ECG shows ventricular fibrillation. What is the most likely cause of his cardiac arrest?
- AMyocardial contusion
- BCardiac tamponade
- CTension pneumothorax
- DCommotio cordis
Show answer & explanationAnswer & explanation
Correct answer: D. Commotio cordis
Commotio cordis is a rare but lethal phenomenon caused by a blunt impact to the chest wall directly over the heart during a critical phase of ventricular repolarization (the ascending limb of the T-wave), leading to ventricular fibrillation. The scenario of a young male struck by a baseball bat is classic for this condition.
Why the other options are wrong
- A. Myocardial contusion can lead to dysrhythmias and heart failure, but a sudden, immediate cardiac arrest with VF from a single blunt blow points more strongly to commotio cordis.
- B. Cardiac tamponade typically results from penetrating trauma or severe blunt trauma leading to pericardial effusion, and while it causes cardiac arrest, VF is not its primary rhythm.
- C. Tension pneumothorax causes obstructive shock and PEA, not typically immediate VF without other preceding events.
Commotio Cordis
Sudden cardiac arrest due to a blunt, non-penetrating blow to the chest wall over the heart, occurring during a critical period of the cardiac cycle, resulting in ventricular fibrillation.
- Often seen in young athletes.
- Impact must occur during the T-wave upstroke.
- Immediate defibrillation is the only effective treatment.
Memory trick: Blunt Blow to Chest: Commotio's Cruel Call.