This sac is called the pericardium. This inflammation can cause a build-up of fluid, blood, or pus that can cause the sack to squeeze the heart. This squeezing makes the heart's job of pumping blood difficult.
People often confuse pericarditis with a heart attack because the symptoms are similar.
If left untreated, pericarditis can be very serious and even fatal. However, current therapies are very effective in curing the disorder. Pericarditis is treated with medications to reduce the inflammation and fluid buildup and to relieve pain. Bed rest is important until the condition has been controlled. Sometimes surgery is necessary to cut a window in the sac to allow it to drain.