Heavy drinking linked to chronic heart disorder, researchers find

PEOPLE who drink a lot, and do so often,
increase their chances of developing the
chronic heart rate or rhythm disorder called
atrial fibrillation, according to Japanese
researchers.
A common arrhythmia, atrial fibrillation
carries a serious risk for stroke. Although
drinking has previously been linked to atrial
fibrillation, the researchers say their new
study shows that habitual drinking as well
as episodic drinking can significantly
increase the risk for the condition.
“Don’t put much confidence in moderate
drinking,” said Dr. Satoru Kodama, from the
internal medicine department at the
University of Tsukuba Institute of Clinical
Medicine and the study ’s lead researcher.
“Chronic high drinking is significantly
associated with risk of (atrial fibrillation),
and the AF risk is related in a dose-response
fashion to daily alcohol drinking, ” he said.
For the study, published online January 18
in the Journal of the American College of
Cardiology, Kodama and colleagues
analyzed 14 studies from around the world,
in a process called a meta-analysis. The
studies involved 130,820 people, including
7,558 who had atrial fibrillation.
The researchers calculated the risk for the
disorder for those who drank the most – at
least two drinks a day for men and at least
one for women, plus the daily drinks
consumed by alcohol abusers and alcoholics
- and compared those figures with the risk
for those who drank the least. Two drinks a
day for men and one for women is often
considered moderate drinking, and other
studies have shown that amount holds
benefits for heart health.
But the Japanese researchers found that
moderate drinkers may have a greater risk
of atrial fibrillation than nondrinkers,
although the risk is not as large as that for
heavy drinkers. Those who drank the most
had a significantly increased risk for atrial
fibrillation, compared with those who drank
the least. Moreover, the risk was
proportionate to the amount of drinking:
The more one drank, the greater the risk.
The researchers noted that their study was
limited in several ways; they had to
estimate the amount of ethanol consumed
when the types of drinks were unknown;
the definition of heavy drinking varied
across studies; and the results may have
been skewed by unknown variables such as
high blood pressure, which was tracked in
some studies but not in others. They added
that the association between atrial
fibrillation and high alcohol intake, for
example, was weaker in studies that
factored in hypertension.
Commenting on the study, Dr. Gregg
Fonarow, American Heart Association
spokesman and a cardiology professor at
the University of California, Los Angeles,
said that, “it is well established that binge
drinking of alcohol is associated with atrial
fibrillation; this is commonly referred to as
‘ holiday heart.’” A number of other studies
also have suggested that moderate or
heavy daily drinking is associated with an
increased risk for atrial fibrillation, he said.
The new study, Fonarow said, found that
the relationship between daily alcohol
consumption and the risk for atrial
fibrillation “appears to be linear, with the
greater the amount of alcohol consumed,
the greater the AF risk, with the lowest risk
of atrial fibrillation being observed in those
who do not consume alcohol. ”
Alcohol can have both direct and indirect
effects on the heart, which can increase the
susceptibility to atrial fibrillation, he said.
“ These include changes in the autonomic
nervous system, changes in blood pressure,
changes in the heart and direct effects on
heart muscle cells, ” Fonarow said.