Even when heart disease is under control, living with it can be a burden, and the emotional toll it takes can cause further heart problems. People who have heart disease may benefit from taking the antidepressant escitalopram (Lexapro).

Lexapro helps protect the heart from some of the damaging effects of mental or emotional stress, according to a recently published study.

Mental stress-induced myocardial ischemia (MSIMI) may occur in up to 70% of all people with stable heart disease.

Specifically, the drug helps protect heart patients from mental stress-induced myocardial ischemia (MSIMI). MSIMI occurs when stress contributes to insufficient blood flow to the heart (ischemia). Some studies suggest that it occurs in up to 70% of all people with stable heart disease.

While the decreased nutrients and oxygen that the heart is receiving don't always cause obvious symptoms, people with MSIMI tend to have worse heart problems than people without MSIMI. And until now, there's been little information on how to treat MSIMI.

Researchers at Duke University Medical Center first screened people with known coronary heart disease for MSIMI. These individuals then were given three mental stress tests — solving a difficult math problem, tracing a star while looking in a mirror and telling a story that made them angry.

An echocardiogram and an electrocardiogram were taken before and after the stress tests. Ischemia either shows up directly as a decrease in the amount of blood pumped by the left ventricle or indirectly as abnormalities in how the heart beats after the stress.

The 127 people who did display ischemia in response to the mental challenge were then divided into two groups: one group took Lexapro for six weeks, starting at 5 mg per day and increasing to 20 mg per day for the last four weeks of the study. The other group took a placebo pill designed to resemble Lexapro. Six weeks later, the people once again took the mental stress tests.

Study subjects who took the Lexapro were 2.6 times less likely to experience ischemia than those who took the placebo. Those receiving the drug also reported feeling calmer and more controlled than those who took the placebo.

Lexapro is a selective serotonin-reuptake inhibitor (SSRI), a class of drug that includes Celexa, Paxil, Prozac and Zoloft. Though the study's results are only preliminary, the researchers suggest that Lexapro or other SSRIs may be helpful to people living with heart disease.

During the study, the participants also underwent exercise stress testing on a treadmill. Lexapro did not lessen the chance of getting exercise-induced ischemia, suggesting that SSRIs only help the heart cope with mental stress, not with physical stress.

An article on the study appears in JAMA, The Journal of the American Medical Association and is freely available.