Studies on gum disease and other infections have provided new clues about why some bacteria may increase the risk of heart disease. The information could lead to novel therapies to prevent heart attacks, or new ways to determine who is most likely to die from cardiovascular disease, scientists reported at the American Heart Assn.'s annual meeting in New Orleans. One study showed that gum, or periodontal, disease was very common among patients who were having heart attacks. Of 76 test subjects, 85% of heart attack patients also had periodontal disease. That compared with only 29% of healthy people who had gum disease.