Dirty Air Pollutes the Heart, Too

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Dirty Air Pollutes the Heart, Too

Study finds it leads to reduced oxygen supply

By Ed Edelson

HealthScoutNews Reporter

MONDAY, July 29 (HealthScoutNews) -- Pollution isn't just hard on the

lungs -- it's bad for the heart, too.

A new study that confirms what many would deem to be common sense says that

fine pollution particles squeeze off the oxygen supply to heart patients

when they exercise.

" It's really been the last couple of years that data have accumulated

showing a relationship between air pollution and heart disease -- increased

incidence of heart attacks and admissions to hospitals during periods of

high air pollution, " says Dr. Murray A. Mittleman. " But we don't understand

the mechanisms by which this happens. This study addresses that issue. "

Finnish researchers put 45 patients with heart disease on exercise bicycles

and had them pedal for six minutes, sometimes when the outdoor air was

clear, sometimes when it was polluted, as the researchers recorded their

electrocardiograms and looked for effects on the heart and blood supply.

What they found, says a paper in tomorrow's issue of Circulation: Journal of

the American Heart Association, was that many of the volunteers were much

more likely to experience ischemia, a reduced supply of oxygen to the heart

muscle, after exposure to polluted air. They also were more likely to have

an abnormal ECG pattern called an ST segment depression, which is linked to

ischemia.

And the research indicates that these cardiac problems are related to

specific air pollutants -- the fine particles that come primarily from

factory smokestacks and the ultra-fine particles that come from diesel

exhausts, among other sources.

The Finnish study thus " highlights myocardial ischemia as a significant

potential mechanism responsible for adverse cardiac outcomes associated with

poor air quality, " says an editorial accompanying the Finnish report

co-authored by Mittleman, who is director of cardiovascular epidemiology at

Beth Israel Deaconess Medical Center in Boston.

The study won't change the advice he gives to patients, Mittleman says.

" I've been telling my patients who are at high risk to avoid excessive

exposure to outdoor air on days of high pollution, to try to avoid exercise

and to spend more time in an air-conditioned environment, " he says.

But the finding could have implications about measures to reduce the health

problems associated with air pollution, " because the sources of the fine and

ultra-fine particles are different from those of larger particles, "

Mittleman says.

And it does indicate locations that people with heart trouble should avoid,

he adds. Fine and ultra-fine particles do not have a long life in the

atmosphere; they tend to clump together to form larger particles. So it is

wise to avoid the emission sources of those small particles, such as bus

depots, he says.

Dr. Len Horovitz, a pulmonary physician at Lenox Hill Hospital in New York

City, says the Finnish study, done at the Unit Environmental Epidemiology of

that country's National Public Health Institute, produced a logical result.

" It is the reduction of the oxygen level in the air that is causing

ischemia, " he says. " Evidently, an area that is polluted has the same kind

of reduced oxygen level as seen in high-altitude areas. "

Horovitz says the results are important for people with lung disorders as

well as those with heart disease.

" We all need a certain level of oxygen " he says. " People who need more

oxygen are at risk when air pollution is high. "

Running the air conditioner is one way to remove particulate pollutants from

a room, Horovitz says. He also recommends use of portable air filter units,

which do the same removal job without cooling the air.

Research to determine what different kinds and levels of air pollution cause

health problems is going on at the Environmental Protection Agency and other

centers, Horovitz says. The results of those studies will have " broad

implications for the kind of legislation that is passed, " he adds.

Meanwhile, Mittleman says, people who don't have heart or lung problems " can

do the common-sense thing. If they have the choice to avoid excessive

exposure on very polluted days, they should do so. "

What To Do

You can learn about air pollution and the heart from the American Heart

Association or the Environmental Protection Agency.

SOURCES: Murray A. Mittleman, M.D., Ph.D. director of cardiovascular

epidemiology, Beth Israel Deaconess Medical Center, Boston; Len Horovitz,

M.D., pulmonary medicine specialist, Lenox Hill Hospital, New York City;

July 29, 2002, Circulation: Journal of the American Heart Association

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