Research Highlights
Study links gene variation to
cardiac effects of mental stress
June 12, 2008
Researchers with VA and the University of Florida have identified a gene
variation in some heart disease patients that makes them especially vulnerable to
the physical effects of mental stress—to the point where blood flow to the heart is
greatly reduced.
"Searching for the presence of this gene may be one way to better identify patients
who are at an increased risk for the phenomenon," said David S. Sheps, MD, MSPH,
associate director of the division of cardiovascular medicine and director of nuclear
cardiology at UF’s College of Medicine, and a staff cardiologist at the Malcom Randall
VA Medical Center in Gainesville.
According to Sheps and colleagues, who published their findings in the April 14
Archives of Internal Medicine, those with the gene variation are three times more likely
to experience dangerous decreases in blood flow to the heart—a condition known as
cardiac ischemia—than heart disease patients without it. Ischemia increases the chance
these patients will suffer a heart attack, heart rhythm abnormalities or sudden death.
The researchers studied 148 older patients with coronary artery
disease. After being injected with a safe radioactive dye, the
volunteers had to give a three-minute speech in front of a small
audience—a task used commonly in research to induce anxiety.
Afterward, they lay down inside a gamma camera—similar in
appearance to a CT or MRI scanner—and underwent imaging that
would trace the isotope in their bloodstream and thus show
blockages in blood flow to the heart. They underwent a similar test
when not in a stressed state and also had blood samples taken for
genetic analysis.
About a quarter of the patients experienced reduced blood flow
to the heart as a result of the mental stress, and about two-thirds of
these patients had a particular variation of the adrenergic beta-1
receptor genotype. This receptor typically helps the body respond
to stress by regulating blood pressure and heart rate, but a variation
apparently makes certain patients more vulnerable to the effects of
psychological stress.
According to Sheps: "We may be able in the future to be more
specific about what kind of treatment might work better in certain
patients depending on their genetic makeup. That is one of the
important things happening in [medicine]. There are many diseases
that already have been shown to respond differently to different
types of treatment based on genetic differences."
The research was supported by VA; the National Heart, Lung and
Blood Institute; and the UF colleges of Pharmacy and Dentistry.
This article originally appeared in the June 2008 issue of VA Research Currents.