Pericardium is the pericardium consisting of inner and outer layers that surround the outer surface of the heart. Pericarditis is defined as inflammation or infection of the heart lining. Various viruses and bacteria attach to the pericardium and negatively affect the functioning of the heart. With inflammation, fluid accumulation may occur between the layers of the vascular membrane. If this amount of fluid is excessive, it may compress the heart and cause an emergency.