[Congenital defects of the left-sided pericardium].

Three patients with congenital absence of the left pericardium and one patient with a partial left pericardial defect are described. Congenital absence of the left pericardium is characterized roentgenologically by levoposition of the heart, a prominent pulmonary artery segment and cardiac apex, interposition of lung between the left hemidiaphragm and the base of the heart, and unusual mobility of the heart. The electrocardiogram frequently shows right axis deviation, an incomplete right bundle branch block and leftward displacement of the transition zone in the precordial leeds. The anomaly has often been mistaken for other heart disease. As an isolated anomaly it is benign and does not require any treatment. Patients with a partial defect of the left pericardium can only be diagnosed lcinically if the left atrial appendage herniates through the defect. The herniation produces a protruding shadow along the left heart border and can be demonstrated angiographically and by fluoroscopy. In isolated cases death caused by herniation and strangulation of larger parts of the heart through a partial left pericardial defect has been described.