If you have chronic heart failure, being around a smoker may be bad for your physical and mental well-being, a new study suggests.
Researchers found that of 205 non-smokers with heart failure, those who regularly breathed in secondhand smoke reported more problems in their day-to-day functioning -- physical and emotional.
The findings, reported in the Archives of Internal Medicine, do not prove that other people's smoke was to blame.
But they add to the large body of evidence tying secondhand smoke to heart disease, researchers say.
A number of studies have found that non-smokers who regularly breathe in other people's tobacco smoke have an increased risk of developing heart disease.
This latest study suggests that secondhand smoke may also affect a heart failure patient's quality of life, according to the researchers, led by Dr. Kirsten E. Fleischmann of the University of California, San Francisco.
"In my opinion, patients with heart failure should definitely avoid secondhand smoke exposure -- both to minimize the risk of cardiac events such as heart attacks and because of the effects on health-related quality of life that we documented," Fleischmann told Reuters Health in an email.
Heart failure is a chronic condition in which the heart can no longer pump blood efficiently enough to meet the body's needs, which leads to symptoms like fatigue, breathlessness and swelling in the limbs.
People can develop heart failure due to a condition that damages the heart muscle, like a heart attack or poorly controlled high blood pressure.
It's possible, according to Fleischmann's team, that secondhand smoke could worsen the situation by impairing blood-vessel function, or increasing inflammation in the blood vessels.
The findings are based on questionnaires and tests from 205 heart failure patients at the researchers' medical center.
One questionnaire focused on "health-related quality of life," which asked about everyday physical and emotional well-being.
Overall, one-quarter of the patients said they were exposed to secondhand smoke at least one hour out of every week. And they scored lower on measures of emotional well-being, and physical and emotional "role" -- meaning they had more physical limitations and emotional problems keeping them from their usual daily routines.
On average, their scores on those measures were 11 to 22 points lower than those of people not exposed to secondhand smoke.
That's a significant difference, Fleischmann said -- akin to effects linked to certain chronic diseases, including heart failure itself.
It's possible, Fleischmann noted, that some other factor, rather than secondhand smoke, accounts for the lower quality of life.
The researchers tried to factor in those things -- like whether people exposed to secondhand smoke were older or in poorer overall health. But they could not control for every variable that could affect a person's health-related quality of life.
Regardless, heart failure patients would be wise to steer clear of tobacco smoke, according to Fleischmann.
Smokers who have a family member with heart failure can help by not smoking around them, Fleischmann said.
"But the best way, of course, is for family members to quit smoking," she added. "This protects both their health and that of their loved one."