The CHADS2 score and its updated version, the CHA2DS2-VASc score, are clinical prediction rules for estimating the risk of stroke in patients with non-rheumatic atrial fibrillation (an abnormal heart rhythm); wherein a high score corresponds to a greater risk of stroke, while a low score corresponds to a lower risk of stroke.
The CHADS2 score and its updated version, the CHA2DS2-VASc score, are clinical prediction rules for estimating the risk of stroke in patients with non-rheumatic atrial fibrillation (AF), a common and serious heart arrhythmia associated with thromboembolic stroke. A high score corresponds to a greater risk of stroke, while a low score corresponds to a lower risk of stroke. 
