Underutilization of antithrombotic therapy in atrial fibrillation.

Most patients with atrial fibrillation should be considered for antithrombotic therapy. In a retrospective survey we investigated practice in two hospitals. For patients at high risk, established guidelines recommend warfarin, or aspirin if anticoagulants are contraindicated; for those at medium risk, either may be used. Of 156 with atrial fibrillation (acute, chronic or paroxysmal), 119 were at high risk, mean age 79 years. According to the guidelines, 89 of these were suitable for anticoagulation but only 49 (55%) received warfarin; 27 received aspirin and 13 neither. Of 27 patients at medium risk (mean age 70 years), 6 were not prescribed any antithrombotic therapy. This survey indicates that guidelines on antithrombotic therapy are commonly disregarded and that, in particular, warfarin is underutilized in the group for whom it is most indicated.