This chaotic pattern of contraction can lead to reduced pumping efficiency and subsequent formation of blood clots, most notably in the left atrial appendage.

[1] Over 90% of stroke-causing clots that originate in the heart in patients with non-valvular AF are formed in the left atrial appendage.

The most common treatment aimed at alleviating the burden of stroke in the setting of AF includes anticoagulation (blood-thinners), which are used to reduce the chance of blood clot formation.

These medications, specifically direct oral anticoagulants (i.e. dabigatran, apixaban, rivaroxaban, edoxaban) and vitamin K antagonists (i.e. warfarin), are very effective in lowering the risk of stroke in AF patients.

The LAA can also be surgically removed simultaneously with other cardiac procedures such as the maze procedure or during mitral valve surgery; specifically, it can be occluded or excluded by over-sewing, excision and resection, ligation, stapling with or without amputation of the LAA or application of a clip system [7][8][9] Finally, the left atrial appendage has been closed in a limited number of patients using a chest keyhole surgery approach.

On March 13, 2015, the U.S. Food and Drug Administration approved the Watchman LAAC Implant, from Boston Scientific, to reduce the risk of thromboembolism from the left atrial appendage in patients with non-valvular AF who are at increased risk of stroke have an appropriate reason to seek a non-drug alternative to blood thinning medications.

Similar to a stent procedure, the device is guided into the heart through a flexible tube (catheter) inserted through the femoral vein in the upper leg.

[14] The patient continues taking warfarin with aspirin for 45 days post implantation at which point in time they return for a transesophageal echocardiography to judge completeness of the closure and the presence of blood clots.

If the LAA is completely occluded, then the patient can stop taking warfarin and start clopidogrel and aspirin for six months after implant.

[27] Theoretical concerns surround the role of the LAA in thirst regulation and water retention because it is an important source of atrial natriuretic factor.