BOSTON -- Promising research being conducted in Boston could offer a new alternative for millions of people with a common heart problem, experts said.

NewsCenter 5's Heather Unruh reported that doctors at Massachusetts General Hospital are testing a new device that may stop strokes and replace the need for people to take blood-thinning medication.

The research is part of a nationwide clinical trial that is enrolling patients.

Judy Carroll is like hundreds of thousands of people who have atrial fibrillation. She needed to take the blood-thinning medication Coumadin, also sold as Warfarin, to protect her heart. But while the drug has proven to be effective at preventing strokes, in rare cases, it can cause them.

"I was really concerned about bleeding," she said.

Blood thinners are not easy to take either. There are food and drug interactions, requiring patients to frequently get their blood checked.

"It's much more of a bother than anyone thinks it is," Carroll said.

Carroll is off Coumadin now after being implanted with a tiny heart device called the Watchman. It's designed to protect the heart from clots and prevent stroke. Researchers all over the nation, including at Mass General, are testing it, to see if it can replace the need for people to take Coumadin.

"It may actually be more effective than Coumadin at preventing strokes," said Dr. Vivek Reddy.

The Watchman is permanently implanted into the heart through a catheter. Tiny hooks hold it into place, sealing off the section of the heart where clots build up.

"It's a filter and any clots that occur on the other end of this device, they can't travel through this filter into the rest of the body and cause a stroke," Reddy said.

About 400 people nationwide have had the Watchman permanently implanted and 97 percent of them are now off Coumadin. Researchers said there have been no side effects.

"We can do this safely, effectively, and the people who receive this device can stop Coumadin and are not having strokes," Reddy said.

Carroll said she is thankful to be off Coumadin.

"It's given me a better quality of life as well as really some freedom of thought, it's peace of mind," she said.

The Watchman has been approved in Europe. If the study in the United States proves it works, it could be approved here.