Congenital Absence of the Left Pericardium

Until the past decade, the diagnosis of congenital absence of the pericardium, partial or complete, had rarely been made prior to postmortem examination or thoracotomy. Since 1963, the condition has been recognized during life in six patients at this institution. Of these six patients, two had partial absence of the left pericardium and four had complete absence of the left pericardium. Characteristic roentgenologic findings were present in all six patients. Associated heart lesions were not present in either patient with a partial pericardial defect. Two of the remaining four had associated heart lesions. One patient had surgical repair of an atrial septal defect. Surgical repair of the pericardial defect was not attempted in any of the six patients. Hemodynamic determinations at rest were normal in all six patients. The two patients with partial pericardial defects, however, had elevation of the pulmonary artery and left ventricular end-diastolic pressures during mild exercise in the recumbent position which suggests that this type of defect is not totally innocuous. In view of the unusual and extreme cardiac mobility in this condition, it is conceivable that a portion of the heart could herniate and transiently incarcerate through the partial defect during exercise. It is suggested that partial pericardial defects may warrant surgical repair. Small defects or complete absence of the left pericardium, however, are apparently without lethal potential and do not require surgical intervention.