Definition of Myocardial contusion:

Myocardial contusion is a "bruise" of the heart muscle.

Causes, incidence, and risk factors:

The most common causes are:

• Auto-pedestrian accident injuries
• Cardiopulmonary resuscitation (CPR)
• Falls from heights greater than 20 feet
• Motor vehicle accidents (usually due to the driver coming into contact with the steering wheel)

Symptoms:

A severe myocardial contusion may lead to signs and symptoms of a heart attack.

Pain in the breastbone (sternum) or front of the ribs alerts the physician that there may have been an injury. There may also be a feeling that your heart is racing.

Other symptoms may include:

• Light-headedness
• Nausea or vomiting
• Shortness of breath
• Weakness

Signs and tests:

Physical exams may show:

• Bruises (contusions) or scrapes (abrasions) of the chest wall
• Crunching sensation when touching the skin (crepitus) if there are rib fractures and puncture of the lung
• Fast heartbeat
• Irregular heartbeat
• Low blood pressure
• Rapid or shallow breathing
• Tenderness to the touch
• Visible abnormal chest wall movement from rib fractures (flail segment)

Tests may include:

• Blood tests (cardiac enzymes, such as Troponin or CKMB)
• Chest x-ray
• Electrocardiogram (ECG or EKG), which records electrical conduction in the heart
• Echocardiogram, which records heart wall motion and valve function

These studies may detect:

• Abnormalities in the ability of the ventricle to contract (wall motion abnormalities)
• Fluid or blood in the thin sac surrounding the heart (pericardium)
• Rib fractures, lung or blood vessel injury
• Defect in the electrical system of the heart (bundle branch block or other heart block)
• Fast heart rhythm originating at the sinus node of the heart (sinus tachycardia)
• Ventricular dysrhythmia (abnormal heartbeats starting in the ventricles, or lower chambers of the heart)

Treatment:

Treatment is usually supportive. Patients are watched for 24 hours and continually monitored by ECG.

In the Emergency Department patients may receive:

• Catheter placement through a vein (IV)
• Medications for pain relief, heart rhythm disturbances, or low blood pressure
• Pacemaker
• Supplemental oxygen
• Various therapies for injuries, such as chest tube placement, drainage of blood from the pericardial sac, or surgery to repair ruptured blood vessels in the chest

Expectations (prognosis):

Mild cases usually recover completely.

More serious injuries to the heart may result in damage to the heart muscles, putting the patient at risk for heart failure or heart rhythm disturbances.

Prevention:

Basic safety precautions are key to preventing myocardial contusion. Wear a seat belt when driving and purchase an automobile with air bags. When working at heights, take appropriate safety precautions.