Atrial fibrillation (AF) is the most common sustained abnormal rhythm of the heart, affects an estimated 2.5 to 5 million individuals in the US, and can lead to stroke, heart failure, and premature death. For those with AF and other stroke risk factors, chronic anticoagulation is recommended to prevent intracardiac thrombus formation and stroke even if the AF is infrequent or short-lived. This standard of care is based partly on our inability to rapidly recognize and respond to AF recurrences which can often be brief and asymptomatic, but exposes the patient to the risk of anticoagulant-induced hemorrhage even during prolonged periods of sinus rhythm where the risk of stroke is presumably low.