By AMERICAN HEART ASSOCIATION NEWS
ANAHEIM, California — Best known for smoothing facial wrinkles, the neurotoxin Botox could one day have a new use: stopping an abnormal heart rhythm that sometimes develops after heart surgery.
Researchers injected botulinum neurotoxin, sold as Botox, into five fatty areas around the hearts of patients having surgery at Duke University Medical Center in Durham, North Carolina. Sixty-three patients received Botox and 67 others were injected with a placebo during coronary bypass surgery, heart valve surgery or both.
Post-surgery AFib occurred in 23 patients receiving Botox compared with 32 patients getting a placebo, a difference of 11.3 percent. But that difference wasn’t considered significant enough to prove the approach worked, cautioned researchers, who presented the findings Wednesday at the American Heart Association’s Scientific Sessions.
Nathan Waldron, M.D., the study’s lead author and a fellow in cardiothoracic anesthesiology and critical care medicine at Duke University Medical Center, attributed the unclear findings to the small study size and said that larger studies are needed to further explore the approach.
AFib after heart surgery affects 27 percent to 40 percent of patients and can lead to longer hospital stays, higher hospital costs and high rates of stroke and deaths from any cause. AFib usually occurs two to three days after surgery, when post-surgery inflammation peaks, Waldron said.
“We need new concepts in preventing post-operative atrial fibrillation,” said cardiologist Renate B. Schnabel, M.D., of the University of Hamburg in Germany, who wasn’t part of the study. No medications currently used are particularly effective — or safe, she said.
The quest to prevent post-operative AFib is complicated by many factors, making it difficult to study, Waldron said.
“It’s not just one mechanism. There’s a huge inflammatory response,” he said.
The reason investigators chose to test Botox is because it targets the body’s nervous system, Waldron said.
“One of the things that’s become clear [is that] the autonomic nervous system plays a large role in creating the background risk and acts as a trigger for post-operative atrial fibrillation,” he said. This may happen as the body reacts to the inflammation caused by heart surgery.
Experts recognized the study for its creative approach.
“The authors presented a positive, innovative way to reduce post-operative atrial fibrillation,” Schnabel said.
And the approach appears to be safe. Even so, Schnabel wonders whether the lack of side effects indicates the drug has no effect on the heart at all — good or bad.
Electrophysiologist Kenneth Ellenbogen, M.D., calls it a “very clever solution that’s very different from what people have been doing before.”
Because Botox wears off over time, it “doesn’t necessarily hang around in the patient for days to months to come” like other drugs that attempt to prevent post-surgery AFib, said Ellenbogen, chairman of cardiology at Virginia Commonwealth University in Richmond, who wasn’t part of the study.
Researchers will dive deeper into study data to look for ways to predict which patients may respond best to Botox treatment after heart surgery, Waldron said.
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