CHA2DS2–VASc score

The CHADS₂ score and its updated version, the CHA₂DS₂-VASc score, are clinical prediction rules for estimating the risk of stroke in people with non-rheumatic atrial fibrillation (AF), a common and serious heart arrhythmia associated with thromboembolic stroke. Such a score is used to determine whether or not treatment is required with anticoagulation therapy or antiplatelet therapy, since AF can cause stasis of blood in the upper heart chambers, leading to the formation of a mural thrombus that can dislodge into the blood flow, reach the brain, cut off supply to the brain, and cause a stroke.

A high score corresponds to a greater risk of stroke, while a low score corresponds to a lower risk of stroke. The CHADS₂ score is simple and has been validated by many studies. In clinical use, the CHADS₂ score (pronounced "chads two") has been superseded by the CHA₂DS₂-VASc score ("chads vasc"), which gives a better stratification of low-risk patients.