Reduced blood supply is probable cause, expert says
WEDNESDAY, Jan. 20 (HealthDay News) -- Heart and lung function appear to be intimately intertwined, so that even mild cases of chronic lung disease affect the heart's ability to pump blood, a new study finds.
"It suggests that a larger subset of heart failure may be due to lung disease," said Dr. R. Graham Barr, an assistant professor of medicine and epidemiology at Columbia University Medical Center and lead author of a report in the Jan. 21 issue of the New England Journal of Medicine.
It's long been known that severe chronic obstructive pulmonary disease (COPD) can have damaging effects on the heart, Barr said. But the new report, which covered 2,816 people in a long-running lung study, shows that "even a mild decrease in lung function affects heart function," he said.
Barr and his colleagues used two imaging techniques, computed tomography (CT) scanning and MRI, to measure both heart and lung structure and function. "We observed a linear straight-line relationship," Barr said.
The probable cause of the loss of ability to pump blood, he said, is a reduced blood supply to the heart.
COPD is the fourth-leading cause of death in the United States. One form of COPD is emphysema, in which lung tissue is destroyed. Another form is chronic obstructive bronchitis, which causes narrowed airways, a persistent cough and excess mucus production. Lung disease is strongly associated with smoking.
The immediate application of the finding to medical practice would be in diagnosis, Barr said. "Our study was not of possible intervention," he said. "Future studies will show how much treatment of the lung affects the heart and how much treatment of the heart affects the lung."
Barr has begun such a study, which he said is in an early stage. "These problems take a long time to develop, and so they take a long time to study," he said. T
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