Blunt cardiac injury

[Justin Bieber]

Blunt cardiac injury is blunt chest trauma that causes contusion of myocardial muscle, rupture of a cardiac chamber, or disruption of a heart valve. Sometimes a blow to the anterior chest wall causes cardiac arrest without any structural lesion (commotio cordis).
(See also Overview of Thoracic Trauma.)
Manifestations vary with the injury.
Myocardial contusion may be minor and asymptomatic, although tachycardia may be present. Some patients develop conduction abnormalities and/or arrhythmias.
Ventricular rupture is usually rapidly fatal, but patients with smaller, particularly right-sided, lesions may survive to present with cardiac tamponade. Tamponade due to atrial rupture may manifest more gradually.
Valve disruption may occur, causing a heart murmur and sometimes manifestations of heart failure (eg, dyspnea, pulmonary crackles, sometimes hypotension), which may develop rapidly.
Septal rupture may not cause symptoms initially, but patients may present later with heart failure.
Commotio cordis is sudden cardiac arrest that follows a blow to the anterior chest wall in patients who do not have pre-existing or traumatic structural heart disease. Typically this blow involves a fast, hard projectile (eg, baseball, hockey puck) with relatively low kinetic energy. Pathophysiology is unclear, but the timing of the blow in relation to the cardiac cycle may be important. Initial rhythm is usually ventricular fibrillation.