April 13 (HealthDay News) -- Depression increases the risk that people with heart disease caused by blockage of coronary arteries will develop heart failure, a new study finds.

That finding was to be expected, said Heidi May, an epidemiologist at the Intermountain Medical Center in Murray, Utah, and lead author of the study, because earlier research had found that depression increases the risk of heart failure in otherwise healthy people. Heart failure is a progressive loss of the ability to pump blood.

What was not expected was the finding that treatment with antidepressant drugs did not reduce the risk of heart failure among people with depression in the group May studied -- 13,708 people who were diagnosed with coronary artery disease.

"I was surprised about that," May said. "Since antidepressants reduce the symptoms of depression, you would think that they would decrease the risk of heart failure." A report on the findings is in the April 21 issue of the Journal of the American College of Cardiology.

Ten percent of the people in the study --1,377 of them -- were struck by depression after being diagnosed with heart disease. The incidence of heart failure in that group was double the rate among those who did not have depression. The increased incidence was lower after adjustment for other risk factors, such as high blood pressure and diabetes, but it was still 50 percent higher.

Medication records were available for 7,719 people in the study, and those records showed no difference in the incidence of heart failure between people prescribed antidepressants and those not prescribed the drugs.

The lesson for physicians, May said, is that there is increased danger for people with heart disease and depression, even if they take medicine that reduces the symptoms of depression. Earlier studies have found that people with depression are less likely to follow recommendations for heart health, such as dieting properly and exercising, and that doctors should emphasize the need for them to follow the rules, she said.

May also said that the same kind of study should be done "in other patient populations to see if the results will be replicated."

Though this was not a controlled trial, considered the gold standard of medical research, the failure to find a protective effect of antidepressant drugs against heart failure "is both new and discouraging," said Dr. Redford Williams, director of the Behavioral Medicine Research Center at Duke University.

"But the study leaves open the possibility that other interventions, such as behavioral therapy, might have an effect," he said. "That is pure speculation on my part. But cognitive behavioral therapy, which teaches patients coping skills to deal with negative thoughts, might be effective."

Williams quickly acknowledged having a personal and financial interest in having that speculation prove true. He said he has developed a life skills program that has shown effectiveness in a clinical trial. If antidepressant medications don't work, such a program might help, he said.

SOURCES: Heidi May, Ph.D., epidemiologist, Intermountain Medical Center, Murray, Utah; Redford Williams, M.D., director, Behavioral Medicine Research Center, Duke University, Durham, N.C.; April 21, 2009, Journal of the American College of Cardiology