RT Book, Section A1 Braunwald, Eugene A2 Jameson, J. Larry A2 Fauci, Anthony S. A2 Kasper, Dennis L. A2 Hauser, Stephen L. A2 Longo, Dan L. A2 Loscalzo, Joseph SR Print(0) ID 1155974634 T1 Pericardial Disease T2 Harrison's Principles of Internal Medicine, 20e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259644016 LK accesspharmacy.mhmedical.com/content.aspx?aid=1155974634 RD 2024/03/29 AB The normal pericardium is a double-layered sac; the visceral pericardium is a serous membrane that is separated from the fibrous parietal pericardium by a small quantity (15–50 mL) of fluid, an ultrafiltrate of plasma. The normal pericardium, by exerting a restraining force, prevents sudden dilation of the cardiac chambers, especially the right atrium and ventricle, during exercise and with hypervolemia. It also restricts the anatomic position of the heart, and probably retards the spread of infections from the lungs and pleural cavities to the heart. Nevertheless, total absence of the pericardium, either congenital or after surgery, does not produce obvious clinical disease. In partial left pericardial defects, the main pulmonary artery and left atrium may bulge through the defect; very rarely, herniation and subsequent strangulation of the left atrium may cause sudden death.