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 22 strokes in the drug group versus nine in the control group.
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 blood levels.
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 about atrial fibrillation.
-- Robert Preidt
SOURCES: Stephen Green, M.D., associate chairman, department of cardiology, North Shore University Hospital, Manhasset, N.Y.
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