Cardiac herniation

Pericardial rupture with cardiac herniation is a rare, highly lethal injury with most patients dying before arrival at a hospital.

Diagnosis in survivors is often delayed because initial chest radiography results are normal or show nonspecific abnormalities before cardiac herniation through the pericardial tear.

Pericardial tears range from short and insignificant to long tears that may lead to cardiac herniation. Tears 8-12 cm in length are associated with cardiac herniation, 90% of which occur along the left pleuropericardium.

Diagnosis

 * CT has shown pericardial tears before cardiac herniation and herniation itself.
 * Signs of a tear include focal pericardial discontinuity; pneumopericardium; and interposition of lung between the aorta and pulmonary artery, heart and diaphragm, or right atrium and right ventricular outflow tract— signs similar to congenital absence of the pericardium.
 * The primary sign of herniation is cardiac displacement when no large pleural effusion, atelectasis, or tension pneumothorax accounts for this displacement.
 * Pneumopericardium is nonspecific, but a large volume of unilateral gas within the pericardium is more diagnostic of cardiac herniation, and has been termed the empty pericardial sac.