DEAR DR. GOTT: My 63-year-old male friend has pericardial effusion.

He had increasing shortness of breath and general weakness for about two weeks before having a procedure to remove the fluid. During the procedure, a liter of blood fluid was extracted, but the biopsy was negative. He has never had any other heart problems but is being treated for emphysema.

He will have follow-up echocardiograms because the fluid is apparently reappearing. The cardiologist does not know the source of the problem and indicated some sort of surgery may be necessary. Can you offer any ideas?

DEAR READER: The heart is enclosed in a two-layered saclike structure called the pericardium. Pericardial effusion occurs when extra fluid gathers between the two layers. Typically, there is a small amount of fluid, but damage, inflammation and more can cause the amount of fluid to increase. As the fluid increases, it restricts the heart's ability to pump efficiently.Symptoms of pericardial effusion include shortness of breath, coughing, fainting, dizziness, painful breathing, chest pain, rapid heart rate, low-grade fever and weakness. In some cases, symptoms may not be noticeable or present. This is especially true in cases in which certain disorders have caused the fluid to increase gradually.There are several causes, including infection, cancer, autoimmune disorders, hypothyroidism, radiation, HIV, chemotherapy, trauma, some prescription medications, kidney failure and more. In some cases, the cause cannot be identified.Treatment varies from person to person depending on the amount of fluid, the cause and whether it is causing or could cause decreased heart function. Common treatments include anti-inflammatory medications and various procedures. These can include needle aspiration to remove the fluid, open-heart surgery (primarily for bleeding into the space), sealing the two layers together and removal of all or part of the pericardium.If your friend has symptoms and recurrent effusion, he needs to follow his cardiologist's advice. Severe or repeated episodes can cause heart weakening, heart failure and death if not treated properly.To provide related information, I am sending you copies of my Health Reports "Coronary Artery Disease" and "An Informed Approach to Surgery." Other readers who would like copies should send a self-addressed stamped No. 10 envelope and a check or money order for $2 per report to Newsletter, P.O. Box 167, Wickliffe, OH 44092.-DEAR DR. GOTT: Can you tell me whether taking a fiber supplement every day is dangerous? I use a fiber drink mix every day and wonder whether it will cause me harm by using it indefinitely.

DEAR READER: To the best of my knowledge, there is no harm in this practice. Fiber is a vital part of the diet. It is indigestible and adds bulk to the feces, which aids evacuation and proper colon health. It is especially helpful to those who suffer chronic constipation. If you remain concerned, speak with your primary-care physician, who can provide more information.To give you related information, I am sending you a copy of my Health Report "Constipation and Diarrhea." Other readers who would like a copy should send a self-addressed stamped No. 10 envelope and a check or money order for $2 to Newsletter, P.O. Box 167, Wickliffe, OH 44092. Be sure to mention the title.