DEAR DR. DONOHUE: My 80-year-old father complained of being so out of breath that he could not take his morning walk. He lives in California, and I live in New York. He says he has diastolic dysfunction. Does that mean congestive heart failure? He can’t explain this to me. Should I insist he leave his home and come live with us? He functions in his daily life, lives alone and drives his car. Please explain this condition. – J.S.

ANSWER: Diastolic dysfunction is one form of congestive heart failure. “Heart failure” indicates that the heart isn’t pumping enough oxygen-carrying blood to the body. “Congestive” refers to a backup of blood in the lungs, where it causes breathlessness, and in body tissues, such as the legs and ankles, where it causes swelling.

In recent years doctors have made a distinction about the phase of the heart cycle that contributes to a particular person’s heart failure – systolic heart failure or diastolic heart failure. With systolic heart failure, the heart muscle is too weak to function as an adequate pump. With diastolic heart failure – your father’s kind – the heart has lost its ability to expand. It can’t accommodate the blood that rushes into it. Blood backs up into the lungs and causes breathlessness.

The distinction between the two forms of heart failure is of more than academic interest. It guides therapy.

Both kinds of heart failure have some common symptoms. Both make people struggle for breath when they are active. Your father’s inability to take his morning walk exemplifies that symptom. Both cause fatigue. Sometimes they waken people from sleep gasping for air.

Salt restriction, water pills and beta blockers are some of the treatments used for diastolic heart failure. Your dad sounds like he is doing fine. I am sure he’ll let you know when he can’t carry on by himself. Until then, you don’t need to insist he leave his home.

DEAR DR. DONOHUE: For many years my friend suffered from myasthenia gravis, and then he went into remission for many more years. The doctor told him he was cured, and he went off medicine – Imuran. In the past six weeks, the illness has come back. What more can be done for him? – J.S.

ANSWER: Myasthenia gravis often goes into extended periods of inactivity, but it frequently resurfaces. During the inactive periods, medicines can be discontinued. In speaking of myasthenia, therefore, it’s better to say “treatable” than “curable.”

In myasthenia, there is a disconnect between nerves and muscles. Acetylcholine, a chemical made by nerves, cannot activate muscles because its docking sites on muscles have been blocked by antibodies. Hence muscle weakness is myasthenia’s primary symptom.

Your friend can go back on Imuran, a medicine used to stop the production of the interfering antibodies. Cortisone drugs are medicines that also moderate the errant immune system that makes these blocking antibodies. Mestinon, a commonly prescribed myasthenia medicine, increases the supply of the messenger chemical acetylcholine and restores muscle strength. He can try it.

Removing the thymus gland is another accepted myasthenia treatment. The thymus gland is a rudimentary gland in the upper chest. Its role in myasthenia is obscure, but its removal relieves myasthenia symptoms for many.

DEAR DR. DONOHUE: I had a relative who died of pancreas cancer one year ago. Nine months later his wife died of the same cancer. Is that just a coincidence, or is there a possible common exposure to something that caused it? – Anon.

ANSWER: There are risks for contracting pancreatic cancer. Smoking is one. And pancreatic cancer runs in some families. But for most people a cause is never found. Your letter made me sit up and take notice. I can’t explain why this happened, and I can’t say if there was a common exposure to some unidentified cancer agent. I suppose we’ll have to be satisfied with coincidence.

I apologize to the letter writer for reconstructing this letter from memory. I put it on my desk but lost it.

DEAR DR. DONOHUE: Please describe a “no-scalpel” vasectomy. I am interested in having the procedure done. My wife and I do not want any more children. – H.F.

ANSWER: The vas is the duct through which sperm travel on their way out of the testicle. In a no-scalpel vasectomy, the doctor, with a forceps, grasps the vas from the scrotal skin surface. Then he or she makes a tiny hole in the skin and through the hole punctures the vas. The hole is so small it heals on its own. The procedure takes about 10 minutes.

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.