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NEW ORLEANS (CNN) -- Mental stress can increase -- even triple -- the risk of death in people with poor coronary artery circulation, researchers said Tuesday.

Patients may not die suddenly while under such stress, but are more likely to succumb to their heart disease later, said Dr. David Sheps, a researcher at East Tennessee State University.

Sheps and colleagues focused their research on volunteers with ischemia -- a condition where blood flow to the heart is reduced. People with bad hearts often suffer chest pain during physical exertion when clogged coronary arteries are unable to supply enough blood to their heart muscle.

But doctors have learned over the past 10 years that mental exertion can also overwork the heart, often without pain -- a condition called silent ischemia.

Sheps' team gave 173 men and women a variety of physical and psychological tests, including a public speaking test.

"They were asked to role-play a scenario where a close relative was being mistreated in a nursing home," Sheps said. The volunteers had to discuss the scenario in front of a small audience.

The study helped identify people with heightened responses to stress that may lead to heart attack. While Sheps' team monitored the volunteers' heart functions, most did not know their hearts were not working properly.

"There were very few who had chest pain," Sheps said.

First large-scale study

Those who had ischemia while doing the test were more likely to die three to four years later, Sheps' team found.

The volunteers' blood pressure typically soared about 40 points, and in half of them, sections of the muscle of the left ventricle began to beat erratically. Eleven of the volunteers died during three to four years of follow-up care, and 44 percent of those had shown the erratic heartbeats during public speaking, while 18 percent did not.

Sheps said those whose hearts reacted badly on the test seemed no more nervous or tongue-tied than did those who weathered the stress without problems.

No studies until now have been large enough to prove that mental stress can actually be fatal for people with coronary artery disease.

The study was financed by the National Heart, Lung and Blood Institute. Sheps presented the findings at a meeting of the American College of Cardiology in New Orleans.

His study found an annual death rate of about 4 percent among people whose hearts have bad circulation during mental stress -- more than three times the risk faced by heart disease patients who do not react to mental stress that way.

Though the researchers focused on public speaking, they said anything that causes mental stress probably is risky for ischemia sufferers.

"As doctors, we all have had patients for whom we have no doubt that an acutely stressful situation has precipitated a cardiac event," Sheps said.

Earlier studies have shown that such hardships as depression, the death of a spouse, losing a job or living through an earthquake increase the risk of fatal heart attacks. However, those studies did not test victims ahead of time for silent ischemia during mental stress.

The Associated Press and Reuters contributed to this report.

National Heart, Lung and Blood Institute
East Tennessee State University College of Medicine
Mayo Clinic HealthOasis on ischemia
American College of Cardiology

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