Myocardial Contusion (Blunt Cardiac Injury)

Incidence unknown, in part due to absence of clear diagnostic criteria/test

2 million motor vehicle accidents/y, with ∼40% involving closed chest injury

20–70% incidence by clinical criteria

16–20% incidence by autopsy

Motor vehicle > falls > crush injuries

Males >females (5:1)

Commotio cordis a rare form of BCI due to low impact chest injury (sports) causing sudden death

Abnormal ECG

Nonspecific ST-T wave changes (70% of trauma pts)

Q-wave and ST-segment elevation

7–17% false negative

60% false positive

Ventricular arrhythmias, most common in cases of contusion

• Trifascicular conduction block.

Other cardiac conditions: Thrombosed or lacerated coronary arteries in spasm, ventricular hypofunction, pericardial effusion/tamponade, pericarditis, valvular insufficiency (left-sided >right), ventricular wall rupture (including septum)

Possible increased risk of cardiac complications (arrhythmias, hypotension) with increased CK-MB troponins and abnormal ECHO

No evidence of increased mortality assoc with GA

Malignant ventricular arrhythmia (acute and delayed)

Cardiac conduction blocks include complete heart block

Hemopericardium

Volume status

Acute hypotension

Delayed myocardial rupture

Associated injuries: Pulm contusion, hypoxemia, injuries to the thoracic aorta, flail chest

Attribution of hemodynamic instability to myocardial contusion versus occult hemorrhage elsewhere

Traumatic injury with hemorrhagic, well-circumscribed lesions of partial or full thickness from myocardial contusion.

Usually affecting the RV but can be multichambered.

BCI frequently seen in severe blunt chest trauma and after CPR and precordial thumps, but difficult to definitively diagnose.

Incorporation of clinical suspicion, anginal chest pain unrelieved by nitrates, ECG—especially ventricular dysrhythmia, CK-MB, troponin I and T levels; 2D ECHO for Dx.

Amount of malignant arrhythmias may be proportional to the severity of myocardial contusion.

Mechanical contusion of myocardium from posterior sternum.

Ram effect from increased transdiaphragmatic pressure or sudden deceleration.

Automobile accident most common cause, representing ∼15% of cases.

Falls ∼10%.

Crash, sports-related assaults ∼15%.