Pericardial sac or pericardium is a fibrous tissue that surrounds the heart. It has two coats:
the outter coat-parietal pericardium
the inner coat-visceral pericardium or epicardium which is double-layered and contains pericardial fluid between those two layers (pericardial fluid is necessary as a lubricant for the heart movement).
Besides lubrication, percardium also protects heart from infections, fixes it and limits its movements.
The wastes would build up in your blood, and can cause serious damage. You can also have serious infections and pain if your kidney is not functioning properly.
