TUESDAY, April 22, 2008 (HealthDay News) -- Researchers have identified a gene variation in heart disease patients who are so vulnerable to the physical effects of mental stress that it causes a major reduction in blood flow to the heart, a condition called ischemia.
Patients with this particular variation of the adrenergic beta-1 receptor gene are three times more likely to experience stress-induced ischemia, which increases the risk of heart attack, heart rhythm abnormalities or sudden death. Mental stress-related ischemia occurs in about 10 percent of all patients with heart disease.
"Searching for the presence of this gene may be one way to better identify patients who are at increased risk for the phenomenon," Dr. David S. Sheps, associate chairman of cardiovascular medicine at the University of Florida's College of Medicine and the Malcolm Randall Veterans Affairs Medical Center, said in a prepared statement.
In this study, University of Florida researchers had 148 coronary artery disease patients, average age 65, perform a public speaking test designed to induce stress. Blood flow to the heart was measured while the patients did the speech task and while they were resting, and patients' blood samples were analyzed for five common gene variations.
About one-quarter of the patients in the study experienced stress-induced reduced blood flow to the heart, and about two-thirds of them had the particular variation of the adrenergic beta-1 receptor gene associated with increased risk for stress-induced ischemia.
The adrenergic beta-1 receptor typically helps the body respond to stress by regulating blood pressure and heart rate. But this common variation makes patients more susceptible to the effects of stress, the researchers explained.
The study was published in the April 14 issue of the Archives of Internal Medicine.
UF researchers are looking for other genetic subtypes that could identify other patients at increased risk for stress-related ischemia.
"We should focus our research on two areas," Sheps said. "One is better identification of patients who are prone to have this problem, and two is looking for effective treatments once we know they have it. We need to know whether we can reverse this phenomenon. We are embarking on other treatment studies fairly soon."
The American Heart Association has more about ischemia.