By Merritt McKinney

      NEW YORK, Jan 11 (Reuters Health) -- A test that measures the heart's response to anger and mental stress may help identify people who are at risk of having a heart attack, researchers report.

      In a new study, investigators found that "patients who reported higher levels of irritability/anger in response to (a mental stress test) were also more likely to display ischemia" -- a reduced oxygen supply to the heart muscle.

      Ischemia, which indicates an increased risk of heart attack, is usually measured during physical exertion on treadmill tests.

      "We've known that most episodes of ischemia don't occur when people are exercising," said the study's lead author, Dr. Mark Ketterer, of the Henry Ford Hospital in Detroit, Michigan, in an interview with Reuters Health. "The likely culprit is mental stress, because people probably spend more of their time mentally stressed than physically stressed."

      Overall, the findings, published in the January issue of the Journal of Health Psychology, suggest that "anger has to be thought of as a risk factor for heart disease," Ketterer said.

      The study included 160 men and 24 women who had heart disease or had experienced a heart attack, and who underwent an exercise stress test on a treadmill to measure levels of ischemia.

      On a later visit, the subjects underwent two 5-minute mental stress tests. In one test subjects participated in a confrontational role-playing game, and in the other they played a computerized word game.

      People who reported high levels of anger or irritability during the role-playing were more likely than others to have ischemia during the test. This was mostly seen in the women in the study, not the men, according to the report. However, the results do not necessarily mean that men do not get as angry as women -- men just may be less likely to admit that they are angry, the authors note.

      In the interview, Ketterer said that men often underestimate their anger when talking with physicians, prompting many doctors to ask a spouse or other family member about a male patient's anger.

      Teaching people how to control their anger may help reduce the risk of heart attack, according to Ketterer. He also noted, however, that some medications may help people avoid losing their temper. Studies are underway to see if certain antidepressants and antianxiety drugs may help people keep their anger under control, Ketterer added.