The most serious problem occurring in RF is called pancarditis ("pan" means total; "carditis" refers to inflammation of the heart).
Pancarditis is an inflammation that affects all aspects of the heart, including the lining of the heart (endocardium), the sac containing the heart (pericardium), and the heart muscle itself (myocardium).
About 40 to 80 percent of all RF patients develop pancarditis.
The valves within the heart (structures that allow the blood to flow only in the correct direction and only at the correct time in the heart's pumping cycle) are frequently damaged during the course of pancarditis.