On Monday, Boston Scientific Corp's stock climbed nearly 4%, thanks to approval of its heart device by FDA.

The agency approved the utilization of the left atrial appendage closure device known as Watchman in patients whose atrial fibrillation causes a high risk of stroke.

The device was approved as an alternative for patients who seek an alternative to blood-thinning warfarin drugs like Coumadin.

According to the American Heart Association, Atrial fibrillation is an irregular heart beat that feels like a quivering heart. This condition affects about 2.7 million people in the US as it increases the risk of stroke.

An irregular heartbeat causes blood to pool in left atrial appendage, an area of the heart where clots can be formed. A stroke can occur if clot breaks away, clogs a vessel and blocks oxygen-rich blood flowing to the brain.

Therefore, doctors often prescribe blood-thinning warfarin drugs to prevent clots from forming in the heart and throughout the body.

However, Boston Scientific and other companies, which are working on left atrial appendage, claim that their devices would help benefit patients who either have had problems due to blood-thinning drugs or who might face problems if they're put on the drugs in long term.

Panels of doctors advised the FDA to approve the device in 2009, 2013, and 2014. However, approval only came this year as the agency wanted longer-term studies on patients.

The Boston-Scientific-Watchman is positioned within the left atrial appendage. It acts as a filter that prevents thrombi from traveling toward the brain. Its frame is made of Nitinol, a common shape memory alloy.

The device is also available in five different sizes to match each patient's own anatomy.