Congenital absence of the pericardium
Congenital absence of the pericardium is a rare cardiac defect first described by Realdo Colombo in 1559. Partial absence of the pericardium is more common than complete absence. These pericardial defects are typically left sided.
Clinical presentation is variable and most defects are detected incidentally during cardiac surgery or during post mortem examinations. Atypical chest pain can occur in some patients. Serious complications can occur when cardiac structures are strangulated within the pericardial defect. In left sided defects, strangulation can occur to left atrial appendage or the left ventricle.
Common cardinal veins supply blood to the pleuropericardial membrane during embryonic development. The right common cardinal vein persists as the superior vena cava which results in closure of the right pleuropericardial membrane. If the left common cardinal vein atrophies early, this could result in defects in left sided pericardium.
In left sided pericardial defects, left atrial appendage and the pulmonary artery can prolapse through the defect. Left ventricle can herniate through left sided defects as well. This results in rotation of the heart to the left. Congenital absence of pericardium can be also associated with other congenital defects, both cardiac and extra-cardiac. Associated cardiac abnormalities include, atrial septal defects, tetralogy of Fallot and patent ductus arteriosus.
- Abnormal echocardiographic windows due to cardiac displacement to the left. Right ventricle is visualised more in left parasternal views
- Enlargement of the right ventricle
- Paradoxical septal motion
- Abnormal swinging motion of the heart in the absence of pericardial effusion.
- Can mimic the appearance of right ventricular fluid overload in conditions like atrial septal defect.
Other imaging modalities
Chest X-ray can show left displacement of the heart, prominent left atrial appendage and pulmonary artery. Cardiac MRI can help to confirm the absence of pericardial tissue, displacement of the heart and identify any associated structural abnormalities of the heart.