Anticoagulation

Because the top chamber of the heart is not squeezing or pumping as efficiently during atrial fibrillation, blood clots may form in the areas where the blood is pooling. If they break loose and enter the bloodstream, they can travel up and block a blood vessel in the brain, causing a stroke.

This can be treated effectively with anticoagulants – medications designed to prevent blood from clotting – such as warfarin or aspirin (if there is less risk of clotting).