People with heart disease were about three times more likely to have ischemia (decreased oxygen supply to heart muscle) during exercise testing after periods of high level air pollution than when they were tested after periods of negligible air pollution, says Juha Pekkanen, M.D., a senior researcher at the National Public Health Institute, Unit of Environmental Epidemiology in Kuopio, Finland.
Although many researchers have reported an association between pollution and increased heart attacks and deaths from heart disease, Pekkanen says this new study is the first to look at myocardial strain and to show ischemia associated with particulate air pollution. Pekkanen says the association between increased risk for ST segment depression, which is measured by electrocardiogram (ECG) and is associated with ischemia, occurred after periods of increased fine and ultra-fine particles in the air.
The researchers findings are based on data collected from subjects living in Helsinki, Finland during the winter of 1998-1999. Volunteers with a history of coronary artery disease agreed to participate in biweekly clinical visits for six months. Each visit consisted of a six-minute, ECG-monitored, submaximal exercise session with a bicycle ergometer. Forty-five heart patients (21 women), average age 68, were in the study. The goal of each exercise session was to achieve a heart rate of 90-100 beats per minute.
Researchers analyzed the data from 342 of the 417 exercise tests conducted. They recorded 72 instances of exercise-induced ST segment depression among the 45 subjects. Twenty-three patients experienc
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Contact: Carole Bullock
carole.bullock@heart.org
214-706-1279
American Heart Association
29-Jul-2002