Even When Silent, Irregular Heartbeat Linked to Stroke
WEDNESDAY, Jan. 11 (HealthDay News) -- Many people may not feel
their heart race when they are having an irregular heartbeat known
as atrial fibrillation, but these silent symptoms double their risk
of stroke, a new study finds.
Of 2,580 study participants with pacemakers who did not have a
history of atrial fibrillation, more than one-third experienced
pacemaker-documented episodes that lasted for more than six
minutes, researchers said. However, 85 percent of these people did
not realize it because there were no obvious symptoms. Pacemakers
are placed in the chest to control abnormal heart rhythms. The
results appear in the Jan. 12 issue of the
New England Journal of Medicine.
The findings don't mean that everyone should be tested or
treated for silent atrial fibrillation (AF), but they do argue for
awareness and tighter control of known stroke risk factors such as
high blood pressure.
"In patients with pacemakers, we do see a very high prevalence of silent AF that is not recognized by the patient," said study author Dr. Jeff Healey, an associate professor of medicine of the Michael G. DeGroote School of Medicine at McMaster University in Ontario, Canada. "Even though they are silent, these episodes are clearly associated with risk of stroke."
Individuals who had one silent atrial fibrillation episode
within the first three months of the study were twice as likely to
have a stroke, when compared to their counterparts who did not
experience any bouts, the study showed. An episode of atrial
fibrillation was defined as an irregular heartbeat that lasted at
least six minutes.
This risk increased with each additional risk for stroke such as
high blood pressure and diabetes, Healey said. All participants
were 65 or older and had a history of high blood pressure.
Researchers followed the patients for about 2.5 years.
"We know that high blood pressure is a very important risk factor for stroke, and this study reinforces the importance of good primary care to pick up these risk factors," he said. "Further research will tell us if it makes sense to screen for silent AF in certain high-risk populations."
Another expert said common sense should prevail.
"We should not check everyone for silent AF," said Dr. Marc Gillinov, a heart surgeon at the Cleveland Clinic. "If you feel palpitations or your heart racing, let your doctor know, but otherwise I would not rush to the doctor. The cause of the stroke is unknown in about 25 percent of people, and a lot of us think maybe subclinical AF plays a role. This study helps answer that piece of the puzzle."
Many questions remain, he said. "The big question is how much AF
is too much because the drugs used to treat AF are very powerful
and have their own issues with safety," he says. "Does one
six-minute episode buy you a lifetime of anticoagulants, or do you
need 10 times that amount?"
Dr. Neil Sanghvi, an electrophysiologist at Lenox Hill Hospital
in New York City, said the new study was "thought-provoking." He
said people should discuss their personal risk factors for stroke
with their doctor to come up with a plan. "The average patient who
has no symptoms should just have a conversation with their
physician," he added.
atrial fibrillation is treated at the U.S.
National Heart, Lung, and Blood Institute.
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