Summary

This article reviews tools for risk stratification for stroke and bleeding among patients with atrial fibrillation (AF). The CHADS2 score is frequently used to estimate the risk of stroke in AF patients and to help determine the appropriateness of anticoagulant therapy. Also discussed are the benefit-risk of warfarin and the new oral anticoagulants (OACs), multiple clinical trials, as well as the measurement and monitoring of the anticoagulant effects of new OACs.