The heart has only one function: to pump blood. The heart is made up of muscles that contract. Aqueous coating around the pericardium within the pericardium layer. This helps to keep the heart in the correct position and prevent it from moving too much or rubbing against other parts of the body. Stiffness is a condition in which the heart is filled with too much fluid in the pericardium. affects the pumping of blood Atrial fibrillation can be life-threatening. Immediate diagnosis and emergency treatment can save lives. Close supervision is imperative.