Emergency Medicine · Trauma
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Commotio cordis is sudden cardiac arrest triggered by a low-energy chest blow landing in the vulnerable 10-30 millisecond window on the upslope of the T wave (R-on-T phenomenon), causing ventricular fibrillation with no structural damage.
Treat commotio cordis with immediate CPR and rapid defibrillation within 3 minutes; survival depends almost entirely on early defibrillation.
Blunt anterior chest trauma causes myocardial contusion, screened initially with a 12-lead ECG and troponin; a normal ECG and negative troponin at 8 hours virtually rules out clinically significant contusion.
Transthoracic echocardiogram is the gold-standard imaging to assess wall motion abnormalities, pericardial effusion, and valvular disruption in blunt cardiac injury.
Cardiac contusion without hemodynamic compromise is managed with 24-48 hours of continuous telemetry monitoring for arrhythmias.
Avoid aggressive fluid resuscitation if right ventricular failure is present, as it worsens hemodynamics; severe contusion risks fatal arrhythmias and free wall rupture.
Distinguish from pericardial tamponade, which shows Beck's triad (hypotension, JVD, muffled heart sounds) and needs emergent pericardiocentesis.
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A 14-year-old boy collapses immediately after being struck in the center of the chest by a baseball during a game. Bystanders report he was well one moment and unresponsive the next. On arrival of first responders he is pulseless and apneic. The automated defibrillator pad reads ventricular fibrillation. There is no external chest wall deformity or bruising.
Which of the following is the most appropriate immediate intervention?
Immediate CPR followed by rapid defibrillation.
This is commotio cordis, in which a low-energy precordial blow during the vulnerable upslope of the T wave induces ventricular fibrillation without structural cardiac damage. Survival depends on immediate CPR and defibrillation within minutes, not on imaging or biomarkers.
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Etiology / Epidemiology
Blunt anterior chest trauma causes myocardial contusions, whereas projectile impact in young athletes causes commotio cordis.
Clinical Manifestations
Contusions range from asymptomatic to cardiogenic shock; commotio cordis presents as immediate sudden cardiac arrest after a chest blow.
Diagnosis
12-lead ECG and Troponin rule out blunt injury; Transthoracic echocardiogram evaluates structural damage.
Treatment
Immediate CPR and rapid defibrillation for commotio cordis; supportive care and telemetry monitoring for contusion.
Prognosis
High mortality in commotio cordis without immediate defibrillation; severe contusions risk fatal arrhythmias and free wall rupture
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Epidemiology & Etiology
Cardiac contusion is a spectrum of blunt cardiac injury typically resulting from high-speed motor vehicle collisions or severe falls. Commotio cordis predominantly affects males < 18 years old playing sports with hard projectiles like baseball, lacrosse, or hockey. The risk of commotio cordis decreases with age due to increasing chest wall rigidity.
Pertinent Anatomy
The right ventricle is the most anterior cardiac chamber, making it the most vulnerable structure to blunt force impact against the sternum. The mechanical impact in commotio cordis occurs directly over the precordium, translating external kinetic energy directly into electrical chaos.
Pathophysiology
In contusion, direct mechanical force causes myocardial edema, hemorrhage, and localized cellular necrosis, leading to impaired contractility. In commotio cordis, a low-energy impact occurs strictly during the vulnerable 10-30 millisecond window on the upslope of the T wave. This mechanical stretch activates mechanosensitive ion channels, triggering premature ventricular depolarization. This mimics the R-on-T phenomenon, immediately precipitating ventricular fibrillation without any macroscopic structural damage.
Clinical Manifestations
Patients with blunt cardiac injury may present with sternal pain, chest wall ecchymosis, or signs of cardiogenic shock. Look for the seatbelt sign or steering wheel bruising as an indicator of severe anterior blunt force. Patients may exhibit new-onset arrhythmias, most commonly sinus tachycardia or premature ventricular contractions. Commotio cordis presents classically as immediate sudden cardiac death following a seemingly innocuous chest blow.
Diagnosis
All suspected blunt cardiac injury requires a 12-lead ECG and cardiac biomarkers (Troponin) as the initial screening. An ECG showing new arrhythmias, conduction blocks, or ST-segment changes mandates admission and further workup. A normal ECG and negative Troponin at 8 hours virtually rule out clinically significant cardiac contusion. Transthoracic echocardiogram is the gold standard imaging to assess wall motion abnormalities, pericardial effusion, or valvular disruption.
Treatment
Commotio cordis requires immediate CPR and rapid defibrillation within 3 minutes for meaningful survival. Cardiac contusion without hemodynamic compromise is managed with 24-48 hours of continuous telemetry monitoring. Patients with cardiogenic shock or severe arrhythmias require inotropic support and intensive care admission. Avoid aggressive fluid resuscitation if right ventricular failure is present, as it can worsen hemodynamics.
Prognosis
Survival in commotio cordis is highly time-dependent, dropping precipitously with every minute defibrillation is delayed. Minor contusions resolve spontaneously, but severe blunt cardiac injury carries a risk of cardiac rupture, ventricular septal defect, and delayed arrhythmias.
Differential Diagnosis
1. Myocardial Infarction: Presents with ischemic ECG changes and elevated troponins, but lacks the acute trauma history.
2. Pericardial Tamponade: Features Beck's triad (hypotension, JVD, muffled heart sounds) and requires emergent pericardiocentesis.
3. Hypertrophic Cardiomyopathy: Causes sudden cardiac death in young athletes, but occurs during exertion without a preceding traumatic chest blow.
4. Pneumothorax: Causes pleuritic chest pain and respiratory distress with decreased breath sounds post-trauma.