In a normal heart, a thin layer called the pericardium surrounds and protects the heart. There is a small amount of fluid between the pericardium and the heart. This fluid helps cushion the heart.
But sometimes too much fluid builds up in this space around the heart. This is called pericardial effusion. This extra fluid puts pressure on the heart and can cause chest pain and serious heart problems.
eMedicineHealth Medical Reference from Healthwise
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