Pediatric emergency medicine trisk 3707 3707

Pericardial tamponade from blunt cardiac injury is rare but life
threatening, and requires immediate pericardiocentesis to avoid
circulatory collapse.
Any patient with suspected blunt cardiac injury who is hemodynamically
unstable or has arrhythmias should undergo echocardiography and be
admitted to the intensive care unit.
All patients with suspected blunt cardiac injury need close follow-up.

Current Evidence
Cardiac injury in blunt thoracic trauma is rare. In one study of 1,288 patients with
blunt thoracic trauma, only 60 (4.6%) had a blunt cardiac injury, though other
smaller studies reported higher incidence. Myocardial contusion, ventricular or
atrial rupture, and valvular disruption are considered blunt cardiac injuries.
Myocardial contusion is the most common blunt cardiac injury, far
outnumbering lacerations. Contusions are usually self-limited; rare complications
include arrhythmia, congestive heart failure, and shock. Also rare is commotio
cordis: cardiac arrest following a single, isolated, forceful precordial blow.
Prompt cardiopulmonary resuscitation/defibrillation is the only identifiable factor
associated with a favorable outcome after commotio cordis.
Cardiac rupture is the most common cause of death in blunt cardiac trauma.
The majority of these patients never reach a hospital because they die at the
scene. The right ventricle is the chamber most commonly ruptured because of its
location directly beneath the sternum. Septal rupture can also occur, with the
condition of the patient correlating with the size of the rupture. Patients with
cardiac rupture may present with cardiac tamponade, demonstrating one or all the
components of Beck triad (jugular venous distention, low blood pressure, and
muffled heart tones). Patients with valvular injury may present in congestive heart
failure with a new regurgitation murmur. Coronary artery injury is rare but should
be considered in patients with electrocardiogram (EKG) changes consistent with
ischemia following blunt thoracic trauma.
Pericardial tamponade may also occur when there is injury to the myocardium

and blood accumulates in the pericardial sac. Because of the nondistensible
pericardium, pressure is exerted on the heart. Cardiac output decreases secondary
to a decrease in venous return and ventricular stroke volume. The body will
initially compensate with an increase in the pulse rate and peripheral vascular
resistance. As the pressure within the pericardial sac increases, the systolic blood