Congenital defects of the pericardium.

Congenital defects of the pericardium are rare, but when they are reported they are frequently associated with other cardiac lesions. We describe a case of partial pericardial defect found incidentally at surgery for closure of an ostium primum atrial septal defect. Proposed mechanisms of pericardial defect development are discussed and we suggest that associations with congenital and acquired heart disease are mostly circumstantial.