DEAR DR. DONOHUE: I have atrial fibrillation. It happens every four to six weeks and lasts from four hours to two days. I was put on Coumadin to thin my blood. Is there anything else that can be done? When it happens, I do nothing – just sit there until it stops. What should I do? Is this a serious problem? – J.W.

ANSWER: Most people with atrial fibrillation have it all the time. You have it intermittently. That doesn’t change its significance. It’s a serious problem.

Atrial fib has two undesirable consequences. One is clot formation in the atria. The atria are the two upper heart chambers. Normally they contract with each heartbeat and shoot blood into the lower heart chambers. When they’re fibrillating, they’re not contracting. They’re quivering like a mound of gelatin. Blood stagnates and forms clots in the noncontracting atria. Those clots can find their way into the general circulation and be swept into a brain artery, where they can obstruct blood flow and cause a stroke. Coumadin prevents clot formation. There are new medicines about to appear on the market that can thin the blood as effectively as Coumadin without having to put up with all the fuss Coumadin use entails.

The second consequence of atrial fib is a loss of some of the heart’s pumping power. For some people, that loss can put them into heart failure.

Are you taking medicine to prevent episodes of fibrillation? You should talk that over with your heart doctor. There are also a number of procedures that can block the transmission of fibrillation messages from atria to ventricles, the lower heart chambers. Those procedures can sometimes restore a normal heart rhythm, but they can also entail having to insert a heart pacemaker.

Don’t just sit there when an episode occurs. Have someone call your doctor or take you to the emergency department of a hospital. The episode should be terminated as quickly as possible.

DEAR DR. DONOHUE: I would like your comments on the effects of the artificial sweetener Splenda on blood sugar. I am a 68-year-old male with type 2 diabetes. I keep my sugar in check with oral medicine and by watching my diet. Since Splenda has become available, I have used it for cereal and my tea and coffee. My favorite yogurt uses Splenda. Also, when my wife bakes cookies or cakes, she uses Splenda.

When I went for my four-month checkup, my hemoglobin A1C was slightly elevated. My daily blood sugar checks have been normal.

Thank you for your comments. – R.M.

ANSWER: Splenda – sucralose – is a somewhat new artificial sweetener that is 600 times sweeter than sugar.

All the information I have on it says it has no effect on blood sugar. That makes sense, because it is not absorbed. I don’t believe it is related to the small rise in you hemoglobin A1C level, and small rises are often inconsequential.

One of its strong selling points is the fact that it can be used in cooking. Many other artificial sweeteners cannot.

For readers’ sake, hemoglobin A1C is a lab test that tells how much sugar is stuck to hemoglobin, the stuff inside red blood cells. It gives an idea of how well blood sugar has been controlled in the previous six to 12 weeks.

DEAR DR. DONOHUE: I am a 38-year-old male, and I take Pravachol daily to lower my cholesterol. I also love grapefruit and eat one every day for breakfast. I have been told numerous times that grapefruit negates the effect of cholesterol medications. Because of this I eat the grapefruit in the morning and then ingest the Pravachol before bedtime. Your thoughts on this would be appreciated. – D.M.

ANSWER: Grapefruit and grapefruit juice do not negate medicines’ action. They can augment some medicines’ effects. Some of the cholesterol-lowering medicines are affected. The evidence for grapefruit’s influence on Pravachol is mixed. Some say it affects it; others say it doesn’t. To play it safe, check with your doctor.

Taking grapefruit in the morning and medicine at night doesn’t undo this effect. The grapefruit influence lasts for 24 hours.

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.

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