"Many studies have linked depression to an increased risk of death in heart disease patients. However, anxiety hasn't received as much attention," Lana Watkins, Ph.D., lead author of the study and an associate professor in Psychiatry and Behavioral Sciences at Duke University Medical Center in Durham, N.C said.
Studies show that depression is about three times more common in heart attack patients.
The American Heart Association recommends that heart patients be screened for depression and treated if necessary.
Depressed heart disease patients often also have anxiety, suggesting it may underlie the risk previously attributed solely to depression, Watkins said.
"It's now time for anxiety to be considered as important as depression, and for it to be examined carefully," she said.
Anxiety and depression each influence risk of death in unique ways.
Anxiety, for example, increases activity of the sympathetic (adrenaline-producing) nervous system that controls blood pressure.
"People who worry a lot are more likely to have difficulty sleeping and to develop high blood pressure," Watkins said.
The link between depression and mortality is more related to behavioral risk factors, she said.
Future studies should test strategies to manage anxiety alone and with depression in heart disease patients, Watkins said.
The research is published in the Journal of the American Heart Association.