DEAR DR. DONOHUE: Recently I was in a life-or-death struggle with pericarditis. Doctors had to drain liquid around my heart twice. Can you tell me more about pericarditis? – A.Z.

ANSWER: A two-layered sac, the pericardium, covers the heart. It keeps the heart in place and enables it to expand when it fills with blood and to contract when it pumps out blood.

With inflammation – pericarditis – the two contiguous layers are raw and sticky. As they rub against each other with each heartbeat, their abraded surfaces produce knifelike chest pain of major intensity. People with pericarditis find they can lessen the pain by sitting up and leaning forward.

Viruses are responsible for many cases of pericarditis. Bacteria, cancer and immune-related illnesses such as rheumatoid arthritis account for the remaining cases, except for the large category of I-don’t-know-the-cause cases.

For most, pericarditis is something that resolves itself in a matter of weeks. Anti-inflammatory medicines – ibuprofen, indomethacin, naproxen and their many counterparts – get people through a pericarditis episode. In especially troublesome cases, cortisone drugs can soothe an irritated pericardium.

You had one of pericarditis’s complications, a pericardial effusion. When that occurs, the space between the two pericardial layers fills with fluid. The fluid-filled pericardial sac can compress the heart and interfere with its pumping. Then the sac must be drained. It can refill and necessitate a repeat drainage.

Now that you are out of the woods, it should be smooth sailing for you. I do have to interject one note of gloom – pericarditis can recur, and for some, it recurs many, many times. Those people constitute a minority of patients.

DEAR DR. DONOHUE: My son is 50. He appears to be in excellent health. He works out in a gym at least three times a week. Last week his doctor told him he had a high rheumatoid factor and a testosterone of 1,100. The doctor did not seem to be concerned. Should we be? – E.S.

ANSWER: Rheumatoid factor is an antibody. Antibodies are the ammunition that the immune system fires at intruders. In rheumatoid arthritis, the lining tissues of joints are mistaken as intruders.

A large percentage of people with rheumatoid arthritis have rheumatoid factor antibodies in their blood.

Your son does not have rheumatoid arthritis. If he did, he would have joint pain and swelling, and his doctor would have told him. He happens to have a positive rheumatoid factor test. It most likely is a quirk, a test that is inexplicably positive.

With age, men’s blood level of testosterone begins to fall. Testosterone is the male hormone that, among other things, keeps muscles healthy and strong. With a declining level of testosterone, muscles begin to shrink. A normal testosterone level lies between 300 and 1,200 ng/dL. By those criteria, your son’s testosterone value is quite normal. (Not all laboratories use the same standards for defining “normal.” Look on the lab slip. It should have the normal range next to the test. If it’s other than the range I cited, write back.)

DEAR DR. DONOHUE: Prior to a colonoscopy in October of ’02, I had an ECG. The only word in lay language on the report was “blockage.” I didn’t ask for an interpretation because the colonoscopy was not canceled. This year I asked my new doctor about it. He said that the word “blockage” indicates a minor disorder, as the natural heart pacemaker is a little slow on the right side. He did not prescribe drugs or refer me to a heart doctor. What do you think? – J.B.

ANSWER: I think the blockage was a right bundle branch block. The heart has two cables that work exactly as electric cables do. They bring the blip of electric current generated by the heart’s natural pacemaker to the lower pumping chambers, the ventricles. Upon receipt of the electric signal, the ventricles pump out blood.

Your right cable has a short circuit. The electric signal reaches your right ventricle, but it has to take a detour. No medicine, no referrals, no diet, no special precautions have to be taken. (Be sure to get this confirmed by your own doctor.)

DEAR DR. DONOHUE: My problem is knowing if I am getting too much exercise.

I am 80 years old. In 1993 I had a six-bypass operation on my heart arteries. Last June I passed a stress test with flying colors.

Each morning I run on a treadmill for 40 minutes. Then I do 5 miles on a stationary bike. That’s followed with 100 pull-ups.

During the day I work four hours as a groundskeeper or walk for 75 minutes.

As long as I feel well, is that too much exercise? – R.W.

ANSWER: It’s not too much exercise if you feel well and if your heart doctor says your heart is fit.

I wish I could accomplish as much exercise. Yours is a grueling program. Maybe I should have a six-bypass operation.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.