Carbon monoxide can damage the brain, but new research suggests poisoning with the colorless, odorless gas can also cause serious harm to the heart. Patients hospitalized for carbon monoxide poisoning are at a significantly increased risk of dying over the next seven years, especially from heart conditions, according to a report in the January 25 issue of the Journal of the American Medical Association. The report breaks new ground, said David G. Penney, a professor of physiology at Wayne State University , who has studied carbon monoxide extensively. \"We know that a certain fraction of people have acute [immediate] cardiac effects, but the fact that it has a long-term effect on increasing mortality is new,\" he said.