Pacemaker May Aid Women More Than Men

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Harvard Medical School
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Pacemaker May Aid Women More Than Men

News Review from Harvard Medical School

June 24, 2014

News Review From Harvard Medical School -- Pacemaker May Aid Women More Than Men

A type of pacemaker can help more women with heart failure than men, and yet women are less likely to get the devices, a study finds. Researchers pooled results from 3 earlier studies. They included 3,198 men and 878 women. Normally, both sides of the heart beat (contract) at the same time. Among people in the study, one side of the heart contracted slightly later than the other. The original studies were designed to test pacemakers that help both sides beat at the same time. Success was measured by a reduction in the risk of death or fewer heart-failure events that required a hospital trip or more medicine. Women with the devices had a 60% reduced risk of these events. Men's risk declined 26%. The study also raised questions about who should get these devices. Guidelines say they should be used if the delay between the two sides of the heart is at least 150 thousandths of a second. But women with slightly shorter delays benefited even more from the devices than the overall group. Men with shorter delays did not benefit. The journal JAMA Internal Medicine published the study. HealthDay News wrote about it June 23.


By Howard LeWine, M.D.
Harvard Medical School


What Is the Doctor's Reaction?

Many women experience heart disease differently than men do. So realizing a woman has a heart problem is often more challenging.

For example, women often do not have typical symptoms of the most common heart problem, coronary artery disease. Some women do not have classic, crushing mid-chest pain with exertion or during a heart attack. Instead, they are more likely to have "atypical" symptoms. Common ones are shortness of breath, sudden severe weakness, sweating all over the body and feeling anxious at unexpected times during the day.

More recently, we are learning that women can also respond differently to heart disease treatments. For example, prior studies have suggested a special treatment for heart failure appears to work better in women than men.

It's called cardiac resynchronization therapy with defibrillator (CRT-D). This study confirms that the therapy not only works better in women, it works much better.

All the men and women in the study had heart failure caused by a weak heart. This is called systolic dysfunction. They also had an abnormal electrical pattern on their electrocardiogram (ECG). The abnormal pattern showed that one part of the heart was contracting later than it should with each beat.

Normally, the muscles of the two main chambers of the heart are synchronized; they contract at the same time. When the heart muscles are "out of sync," a weak heart pumps blood even less effectively than it would with a normal electrical pattern on ECG.

Treatment for these types of patients always includes heart failure drugs. These drugs help them live longer and help protect the heart from getting weaker. But they also receive either a plain implantable defibrillator or a CRT-D. The plain defibrillator shocks the heart if it goes into a life-threatening heart rhythm. The CRT-D stimulates the heart muscles to work together more effectively. It also can shock the heart if needed.

The guidelines for which patients should get a CRT-D were based on studies in men. This new study found that women with heart failure and a heart that is out of sync may need a CRT-D based on less stringent criteria. But even based on existing guidelines, women now tend to receive CRT-D's less often than men.


What Changes Can I Make Now?

If you have heart failure caused by a weak heart, your first goal is to maximize your drug treatment. The drugs for heart failure help you feel better and also prolong your life.

Next, find out if your electrocardiogram shows an abnormal pattern that might make you a candidate for a CRT-D. In the right person with heart failure who is taking medicines as prescribed, CRT-D can help:

  • Reduce symptoms such as shortness of breath, fatigue and leg swelling
  • Prolong life
  • Reduce the risk of needing hospital care, increased doses of water pills or both

CRT-D may also prevent heart failure from getting worse.

The most common causes of heart failure in the United States, Canada and Europe are coronary artery disease, high blood pressure and excess use of alcohol.

Most cases of heart failure can be prevented. Here's what you can do:

  • Eat a healthy diet. Don't take in more calories than you burn.
  • Exercise regularly, starting today.
  • Limit alcohol to an average of one drink a day for women and no more than two per day for men.
  • Get your blood pressure checked regularly. Lower it if necessary.
  • Reduce your cholesterol level if it's high. Take a statin drug if diet alone is not enough.
  • Don't smoke.


What Can I Expect Looking to the Future?

More women with heart failure and an abnormal pattern on ECG will be receiving a CRT-D. Further studies will look at whether these less stringent criteria might also be applied to men.

Last updated June 24, 2014

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