Traumatic Pericardial Rupture

Traumatic pericardial rupture is a tear of the pericardium from blunt or penetrating trauma. It may lead to herniation of the heart through the defect, with obstruction to venous return and sudden collapse.

Epidemiology. It is rare and found in under 1% of blunt chest trauma. Most cases are found at operation or autopsy. Mortality is about 40% in reported series, mostly from associated injuries.

Mechanisms. Severe blunt force from road traffic collision or crush, sudden rise in intrathoracic or intra-abdominal pressure, and penetrating injury. Left sided tears are more frequent (about 65%) and are often combined with a rupture of the left pleura. Right sided tears and diaphragmatic tears can also occur.

Pathophysiology. Through a large defect the heart can herniate into the pleural cavity, with torsion of great vessels, strangulation of the ventricles, obstruction of the venous return and cardiac output, and arrhythmia. Small defects can strangulate a part of the ventricle. Usually pericardial fluid and blood drain to the pleural cavity, which reduces the risk of tamponade.

Presentation is sudden hypotension and shock, often with a change in position (when moved or ventilated), arrhythmia, cardiac arrest or no signs. Other findings are an abnormal apex beat, muffled heart sounds, a displaced mediastinum, bowel sounds in the chest and signs of associated injuries (haemothorax, rib fractures, diaphragm rupture).

Red flags.

• Hypotension that varies with position, or after starting positive pressure ventilation.
• Cardiac arrest or severe shock with blunt chest trauma.
• Absence of cardiac silhouette in its usual place on chest radiograph.

Chest radiograph (dextroposition or levoposition, a "tilted" or absent cardiac border, air within the pericardium, pneumopericardium). CT chest is the best test (heart displaced, pericardial discontinuity, "collar sign" of cardiac herniation). Echocardiography and extended ultrasound examination (heart in an abnormal position). Diagnosis is often made at thoracotomy.

Differential diagnosis. Cardiac tamponade, tension pneumothorax, massive haemothorax, aortic injury, blunt cardiac injury and mediastinal shift from other causes.

Resuscitation. Airway, breathing and circulation. Position the patient (for example, right lateral decubitus for left sided herniation) if positional hypotension, and minimise positive airway pressure. Transfuse blood for associated bleeding.

Surgical repair. Urgent thoracotomy (left anterolateral) or median sternotomy, with reduction of the heart, repair of the pericardium (primary closure for small tears, patch of bovine pericardium or synthetic material for large defects) and repair of associated cardiac, lung or diaphragm injury. Cardiopulmonary bypass is available for complex injuries.

Arrhythmia. Amiodarone 150 mg IV over 10 minutes, then 1 mg/min for 6 hours, then 0.5 mg/min, after correction of potassium and magnesium.

Monitoring. Haemodynamics, continuous ECG, drain output, echocardiography after surgery.

Referral and escalation. Cardiothoracic and trauma surgery at once, and cardiac anaesthesia.

Special groups. In pregnancy, left lateral tilt and obstetric input.