Pericardial disease affects the pericardium, which is the flexible two-layered sac that envelops the heart.
The pericardium helps keep the heart in position, helps prevent the heart from overfilling with blood, and helps protect the heart from being damaged by chest infections. However, the pericardium is not essential to life. If the pericardium is removed, there is little measurable effect on the heart's performance.
Normally, the pericardium contains just enough lubricating fluid between its two layers for them to slide easily over one another. There is very little space between the two layers. However, in some disorders, extra fluid accumulates in this space (called the pericardial space), causing it to expand.
Rarely, the pericardium is missing at birth or has defects, such as weak spots or holes. These defects can be dangerous because the heart or a major blood vessel may bulge (herniate) through a hole in the pericardium and become trapped. In such cases, death can occur in minutes. Therefore, these defects are usually surgically repaired. If repair is not feasible, the whole pericardium may be removed. Other disorders of the pericardium may result from infections, injuries, or the spread of cancer.
The most common disorder of the pericardium is inflammation (pericarditis). Pericarditis may be
- Acute (inflammation that develops shortly after a triggering event)
- Subacute (inflammation that develops a few weeks to a few months after a triggering illness)
- Chronic (inflammation that lasts longer than 6 months)
Other disorders of the pericardium include
- Pericardial effusion
- Constrictive pericarditis
- Fibrosis of the pericardium
Pericardial effusion is accumulation of fluid in the pericardium. Cardiac tamponade occurs when a large pericardial effusion prevents the heart from properly filling with blood and therefore prevents the heart from pumping enough blood to the rest of the body.
Constrictive pericarditis, which is rare, occurs when the fluid that accumulates is thick and fibrous and causes the layers of the pericardium to stick together. Constrictive pericarditis can be transient, for example if it is caused by an infection, or chronic if it occurs after a disorder that causes acute pericarditis.
Fibrosis of the pericardium may follow purulent pericarditis (pericarditis caused by an infection and in which the pericardial effusion is pus-like) or accompany a connective tissue disorder such as rheumatoid arthritis. In older patients, common causes are malignant tumors, heart attacks, and tuberculosis.
Hemopericardium (accumulation of blood within the pericardium) may lead to pericarditis, pericardial fibrosis, or cardiac tamponade. Common causes include chest injury, injury as a result of medical procedures such as cardiac catheterization and pacemaker insertion, and rupture of a thoracic aortic aneurysm.