DALLAS (AP) - Heart patients with chronic depression are three times more likely to suffer a second heart attack within a year of their first one, a study found.

Short-term depression is common after a heart attack. The new findings suggest, however, that if depression lingers and there is no support from family, friends or mental health professionals, a second heart attack is likely.

"It's that chronic depression that's so troubling - about half of them remain depressed," said lead researcher Nancy Frasure-Smith of the Montreal Heart Institute. "That's not something that just goes away."

The study was published in Monday's issue of Circulation, an American Heart Association journal.

The researchers surveyed 887 people who had suffered heart attacks. About a third reported lingering depression after their attacks. Within a year, 7.5 percent of those died of heart disease compared with 2.5 percent of those with short-term depression.

Sarah Knox of the National Institutes of Health said the findings are further proof that the psychological health of heart patients is just as important as their physical health.

In a study released in August, Carnegie Mellon University researchers found that patients with lower measures of self-esteem, optimism and feelings of control were more likely to experience a second blockage within six months than those with better attitudes.

The 300 subjects in the Carnegie Mellon study had undergone an angioplasty, in which a balloon is used to clear a blockage in a blood vessel.

Copyright 2000 The Associated Press. All rights reserved.