DEAR DR. DONOHUE: What’s the meaning of “heart block”? Where is the block? My husband has it. His brother also had it and had to have a pacemaker. My husband’s doctor hasn’t said anything about that. What can we expect? – K.R.

ANSWER: This kind of block has nothing to do with a block in a heart artery. It’s a block in the heart’s electrical system.

High in the upper part of the heart is a group of special cells that act like an electric generator, producing an electric pulse 60 to 100 times a minute. Those cells are the heart’s pacemaker. The electric blip travels to the heart’s two pumping chambers, the ventricles. When it reaches them, they contract and pump blood out of the heart.

A heart block indicates that there’s a glitch somewhere in the electric system between the natural pacemaker and the ventricles.

Ask your husband’s doctor what kind of heart block he has. There are three different kinds: A first-degree heart block is something seen on an EKG. People with it have no symptoms. It’s not a serious condition and needs no treatment. A second-degree heart block has some importance. With this kind of block, some, but not all, electric signals make it to the ventricles. This kind of block often needs treatment, and sometimes the treatment is a pacemaker. Symptoms of a second-degree block might be fainting spells and/or skipped beats. A third-degree heart block is the most serious kind of block. No electric signals reach the ventricles, but they keep on beating because they’re able to generate their own electric current. However, the heartbeat is slow, and people often have fainting episodes. They need a pacemaker quickly.

Your husband’s block must be a first-degree block, but have his doctor tell you that.

The booklet on heartbeat irregularities discusses the more common kinds of heart-rhythm disturbances. Readers can obtain a copy by writing: Dr. Donohue – No. 107, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: Last week, during a movie, I saw flashes of light that looked like a small fireworks display. It lasted only a few seconds. Since then, I have what I think are called floaters. They are annoying, but I can see as well as ever. Is this a matter I should see an eye doctor for? – L.U.

ANSWER: Yes, you should, and I hope you haven’t waited for a response in the paper.

Many people have floaters – little black dots that dart through a person’s visual field. Moving the eye makes floaters float around. Age and nearsightedness are often responsible for them. Most floaters are not a sign of an imminent calamity.

However, you describe something that can’t be ignored. The brief episode of flashing lights suggests that your retina was stimulated. Stimulation, in this circumstance, could mean that the retina is detaching from its position at the back of the eye. The sudden onset of floaters is another indication that bad things are happening, like a retinal detachment. Get to an eye doctor immediately. I hope you have already done so.

DEAR DR. DONOHUE: My mother-in-law is undergoing chemotherapy for breast cancer. I have a friend who says my children should not visit her while she’s taking chemo. I have never heard that. Is it true? – W.O.

ANSWER: It’s not true. It’s foolishness.

DEAR DR. DONOHUE: I eat fruit and vegetables for breakfast, lunch and dinner. Am I overdoing it? – P.C.

ANSWER: No, you’re not overdoing it. Many people live exclusively on fruits and vegetables, and they are quite healthy – healthier than the rest of us. Your diet is the sort of diet that lessens the chances of having a heart attack and stroke. It also keeps blood pressure and cholesterol in the low numbers. Stick with it.

DEAR DR. DONOHUE: I am too embarrassed to speak to my doctor about my problem. An intense orgasm gives me excruciating pain on both sides of my head. It’s the worst headache I’ve ever had, but it lasts only one minute. What causes it? – W.H.

ANSWER: Speak to your doctor. This isn’t a matter of embarrassment. It’s an orgasm headache, and it’s not such a rarity. The increase in blood pressure and heart rate that occurs at the height of sexual excitement might be the cause. Such headaches can be on one side or on both sides of the head, and they last up to 15 minutes. Some have found relief by taking a nonsteroidal anti-inflammatory medicine like ibuprofen before relations.

There are serious causes of such headaches. A leaking brain aneurysm is a case in point. An aneurysm is a bulging weak spot on an artery wall. Such a headache is always spoken of as being “the worst headache of my life.” This is another reason to see a doctor.

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. Readers may also order health newsletters from www.rbmamall.com