* Device already on market for ablation of heart tissue
* Maker looking to add atrial fibrillation use to label
* Panel says effective, concerned about safety
GAITHERSBURG, Md., Oct 26 (Reuters) - U.S. health advisers on Wednesday gave their nod to a label revision for AtriCure Inc's device for treating a heart rhythm disorder.
A panel of outside experts convened by the Food and Drug Administration voted unanimously that the Synergy Ablation System was effective in treating persistent and long-standing persistent atrial fibrillation during open-heart surgery.
Votes were divided over safety concerns and, with the panel chairman stepping in, the final vote was 5-4 with one abstention that the device was safe. The panel voted 5-3 with one abstention that benefits outweighed risks.
If approved for a new label, the AtriCure device would be the first surgical ablation treatment for atrial fibrillation, and third ablation treatment for afib overall.
AtriCure's ablation device is already approved for heart tissue ablation during surgery. It uses radiofrequency energy to remove or destroy problem-causing heart tissue.
The company hopes to expand the label to add the use of the device to restore normal heart rhythm in patients with persistent or long-standing persistent atrial fibrillation who require open-heart surgery.
Atrial fibrillation is the most prevalent heart rhythm disorder. It affects more than 2 million Americans and is a major cause of stroke. In the condition, the heart's upper two chambers contract rapidly and irregularly and don't properly pump blood into the lower chambers.
Persistent afib is one that does not go away after seven days or requires intervention to stop; the long-standing persistent kind continues longer than a year.
Without an indication specifically for atrial fibrillation, AtriCure has been prohibited from training physicians to use its device to treat the disorder or discussing the condition in any way. Doctors legally could still use the device for the procedure, but off label.
"The device is being used for this indication every day ... The cat's out of the bag and I think it can only become a safer and more effective procedure with adequate training," said panel member Dr. Richard Page, a cardiologist from the University of Wisconsin-Madison.
Even though the company said its device is already widely used for treating afib during open-heart surgery, it ran into roadblocks enrolling people into a trial, which ended up involving 55 patients.
With murky definitions of different afib stages, four of 55 turned out to have paroxysmal afib, which means recurring but lasting less than seven days and could indicate a healthier patient. FDA researchers, in their review, raised concerns that those four could be skewing the results.
Panel members appeared less concerned with that, but zoomed in on the adverse impacts noted in some of the patients after they got afib treatment with AtriCure's device in surgery.
The incidents were few, but included both less serious issues, such as an atrial or vein tear, and more troubling ones such as stroke and even death. Also, patients after the afib treatment appeared likelier to need pacemakers.
"The issue is that the major safety events that were outlined in the protocol were not device-related," AtriCure's President and CEO David Drachman told Reuters after the vote.
But it couldn't be definitively delineated whether the incidents were caused by the afib treatment, the open-heart procedure that is risky in itself or the general fact that patients who came in had major health problems to begin with.
"(It) is a very thorny and difficult disease to deal with and it would be unreasonable to expect perfect efficacy," said panel chairman Dr. John Hirshfeld, a University of Pennsylvania cardiologist, highlighting that the device did in fact show some efficacy. "It's not clear yet how effective (the device) is and how durable this effect is going to be and this really requires more comparative data down the road."
The company plans a larger trial to further study the device's risks and benefits as a post-approval trial.
"The AtriCure team has been working on this project for almost ten years ... We're very proud," CEO Drachman said.
The FDA will make a final decision on the label. It usually follows the advice of its advisers but does not have to.