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Oct-14-2004 (HealthDayNews)
Each year, about 100,000 American
die suddenly from heart attacks with no warnings or previous
symptoms of heart disease.
"If
this happens out of the hospital, the chances of survival are
only around 5 percent," Dr. Phil Adamson, the lead author of
the new study, said Thursday at the 23rd annual American Medical
Association Science Reporters Conference in Washington, D.C.
The study appears in the Oct. 26 issue of the Journal of
the American College of Cardiology.
Adamson, an associate professor
of medicine at the University of Oklahoma Health Sciences Center,
and his team used research on dogs to show how the dietary
supplement can lead to potentially lethal heart rhythms and
then sudden heart attack.
Adamson, a consultant to his university's
athletic department, began the study a year and a half ago,
before ephedrine was banned by the U.S. Food and Drug Administration
in February. But Adamson fears that many people, especially
athletes who want to improve performance, still take the supplement,
buying it over the Internet.
"People are resourceful," he said,
adding he hopes the new research will convince people of the
dangers of ephedrine, even if they think their hearts are healthy.
In Adamson's experiment, the researchers gave ephedrine supplements
to dogs at a dose recommended on the label. Ephedrine speeds
up the body's sympathetic nervous system, the part of the nervous
system that makes the heart beat stronger and faster. Prior
to administering the supplement, the researchers induced a
reversible blockage in the animals' heart arteries. The purpose:
To mimic what happens to people with ischemic heart disease,
in which the blood supply to the heart becomes constricted
but the person is unaware of the problem because there are
often no symptoms until the fatal heart attack. When the blockage
occurred, the animals' heart rates escalated dramatically.
In the 15 animals, nine experienced a dangerous, wild beating
of the heart and four had abnormal heart rhythms that prevented
the heart from pumping normally. Three couldn't be resuscitated.
The ephedrine "super-powered" the sympathetic nervous system,
Adamson said, resulting in great instability of the heart's
electrical activity.
The new findings are no surprise to Mark
Blumenthal, founder and executive director of the American
Botanical Council, a nonprofit organization that uses "science-based
and traditional information to promote the responsible use
of herbal medicine."
"Since 1997, industry policy has been
to label any herbal dietary supplements containing the now-banned
herb ephedra with warnings that anyone with cardiovascular
disease, hypertension or other cardiac illness should consult
with a qualified health-care practitioner before using products
with ephedra."
The value of the new research, he said, may
be to warn those who don't know they have heart problems that
the herb may be risky for them.
More information
To learn more
about herbs and dietary supplements, visit the American
Botanical Council.
SOURCES:
Phil Adamson,
M.D., associate professor of physiology and medicine-cardiovascular
diseases, University of Oklahoma Health Sciences Center, Oklahoma
City;
Mark Blumenthal, executive director, American Botanical
Council, Austin, Tex.; Oct. 26, 2004, Journal of the American
College of Cardiology; Oct. 14, 2004, presentation at 23rd
annual American Medical Association Science Reporters Conference,
Washington, D.C.
Copyright © 2004 ScoutNews
LLC.
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