-- Common emotions such as tension, frustration, and sadness can trigger a drop in the blood supply to the heart, researchers say.

A new study of heart patients demonstrates that high levels of such mental stresses in daily life more than doubles the risk of myocardial ischemia -- an insufficient blood supply to heart tissue -- that can be a precursor to heart attacks.

"This is the first time the degree of risk associated with stress has been documented, and we were very surprised at the importance of negative emotions in triggering ischemia, as well as the size of the risk," says lead study author Elizabeth C.D. Gullette, a doctoral student at Duke University Medical Center9s behavioral c&diology laboratory in Durham, North Carolina.

"Only a minority of patients we studied experienced chest pain, suggesting that patients were unaware that stress was affecting their hearts," she added.

In the study published in this week's issue of The Journal of the American Medical Association, Gullette and her Duke colleagues enlisted 132 patients with coronary artery disease (CAD) and recent evidence of ischemia induced by exercise. Participants wore ambulatory electrocardiographic ~CG) monitors at home and at work for 48 hours.

Participants were asked to keep diaries of their activities, moods, and symptoms three times an hour -- during waking hours -- over the two days. On a scale of 0 to 4, they rated themselves on five emotional states -- sadness, frustration, tension, happiness, and feeling in control.

For 58 of the 60 participants who showed ECO signs of ischemia, the researchers then applied a recently developed method of statistical analysis that paired readings of heart activity with diary records.

They found that the episodes of ischemia were more than twice as likely to occur in the hour following emotional stress compared with the nonstress hours.

High levels of the negative emotions (tension, frustration, sadness) were associated with a two- to three-fold increased risk for ischemia than low levels of these emotions.

In earlier studies conducted at Duke, researchers demonstrated that in an experimental setting, stress caused by performing challenging mental tasks can cause ischemia and that the risks of future cardiac events -- heart attack, surgery, death -- were increased three-fold among patients who showed mental stress-induced myocardial ischemia. "The current study extends our earlier experimental findings into the real world," says Gullette. "This approach enabled us to clarify causal relationships between risk factors and events. By examining patients' activities and emotions in the hour prior to the ischemic episode, we can gain tremendous insight into those factors that might trigger myocardial ischemia."

In addition to the higher ischemia risk linked with negative emotions, the Duke team also found that the heart patients had a 13 times higher risk of ischemia after heavy activity -- aerobic exercise, jogging, power walking -- and a two times greater risk after moderate and light activity.

But Gullette notes that heavy activity occurs relatively infrequently, while stress levels may vary significantly over the course of the day.

What about the relevance of the new findings to people who do not have CAD?

"Without wanting to generalize too much, it's certainly possible that negative emotions may have subtle, subclinical (no symptoms) effects on people without heart disease," Gullette says. "Everybody should pay attention to those kinds of relationships, but it's really heart patients in particular that we're speaking to."

Commenting on the findings, Drs. Murray Mittleman and Malcolm Maclure, both of Harvard School of Public Health, write that the Duke findings suggest that prior reports on the cardiac effects of rare stressful events such as earthquakes and war "presented only the tip of the iceberg."

Still, according to Mittleman and MacClure, whether low levels of mental stress "are capable of triggering the more dire consequences of CAD, such as myocardial infarction (heart attack) or sudden cardiac death, requires further study."

SOURCE: The Journal of the American Medical Association (1997;277(20): 1521-1526, 1558-1559)