-- Robert Preidt
MONDAY, Nov. 14 (HealthDay News) -- A once-promising drug for a
common and dangerous form of irregular heart rhythm actually seems
to raise the odds for patient death, a new study finds.
The drug, dronedarone, had seemed effective against the
non-chronic, "intermittent" form of atrial fibrillation in prior
trials. But in the newer trial -- involving patients with ongoing,
"permanent" atrial fibrillation -- use of dronedarone was tied to a
doubling of the patients' death risk. The trial was cancelled early
due to concerns over the drug's safety.
Atrial fibrillation is a heart rhythm disorder affecting about
2.7 million Americans that often occurs with age and can raise
risks for stroke. In people with intermittent atrial fibrillation,
the heart may return to normal rhythm on its own. But it does not
do so in people with the more permanent form, who usually receive
medications to control their heart rate.
One expert said the new study provides valuable guidance to
doctors and patients.
"Rather than being a failure (which it is for the drug), this study is a 'win' for the cardiology community, in that it has tested and shown that this agent should not be used in such a fashion," said Dr. Stephen Green, associate chairman of the department of cardiology at North Shore University Hospital in Manhasset, N.Y.
The study was slated for presentation Monday at the annual
meeting of the American Heart Association in Orlando, Fla. It is
also being published simultaneously in the
New England Journal of Medicine.
Dronedarone is currently used to treat intermittent atrial
fibrillation but is not approved for treatment of the permanent
form of the condition. This study was designed to investigate if
dronedarone would benefit patients 65 and older with permanent
atrial fibrillation, but it was halted after enrolling only 30
percent of the intended 10,800 patients.
Compared to those taking a placebo, patients who took
dronedarone were 2.2 times more likely to suffer a major vascular
event such as stroke, heart attack, systemic blood clot or
cardiovascular death, the researchers found.
There were 21 cardiovascular deaths in the dronedarone group and
10 in the placebo (control) group; 13 deaths linked to arrhythmias
(heart rhythm disorders) in the dronedarone group and four in the
control group; and 23 strokes in the drug group versus 10 in the
The researchers also found that dronedarone increased the risk
of hospitalization for heart failure and that the nearly one-third
of patients in the dronedarone group who had been taking the heart
rhythm drug digitalis had a 36 percent rise in their digitalis
That suggests that an "increase in digitalis played a causative
role in the increased risk of cardiovascular death," lead author
Dr. Stuart J. Connolly, a professor of cardiology at McMaster
University in Hamilton, Canada, said in an American Heart
Association news release. "But this does not explain the increase
in stroke or heart failure," he added.
Still, "the message is that the drug dronedarone should not be
used for permanent atrial fibrillation," Connolly said.
Green agreed. "The pertinent points are: Antiarrhythmic agents
have traditionally had a difficult risk/benefit ratio, and
large-scale studies are useful to choose the correct patient for
the correct drug," and, "it is important to trial agents for
non-FDA-approved indications, rather than use them
indiscriminately," he explained.
The U.S. National Heart, Lung, and Blood Institute has more
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