What Is It?
Pericarditis is an inflammation of the pericardium, the saclike membrane that surrounds the heart. Pericarditis can be triggered by a number of different medical conditions. Often the exact cause cannot be identified. Doctors call this idiopathic pericarditis.
In many people with pericarditis, the initial trigger is a viral infection. However, the inflammation may not be a direct result of the infection. Instead, the virus may stimulate the immune system to attack and inflame the pericardium.