Pericardial disease affects the pericardium, which is the flexible two-layered sac that envelops the heart.

The pericardium helps keep the heart in position, prevent the heart from overfilling with blood, and 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). Inflammation may develop shortly after a triggering event. Such sudden inflammation is acute pericarditis (see Pericardial Disease: Acute Pericarditis). Other times it may take a few weeks to a few months for pericarditis to develop. Pericarditis that develops within a few weeks to a few months after a triggering illness is called subacute pericarditis. Pericarditis that lasts longer than 6 months is chronic pericarditis (see Pericardial Disease: Chronic Pericarditis).

Last full review/revision August 2012 by Brian D. Hoit, MD