Several large trials have shown that the risk of stroke in patients with non-valvar atrial fibrillation is reduced by treatment with warfarin. Implementing this research evidence requires not only an understanding of the trials' results and of the changes that they imply for clinicians' treatment decisions but also an appreciation of the organisation, quantity, and quality of services required to support these changes. Understanding of these implications is crucial for developing services that allow changes in practice to produce reductions in stroke incidence while minimising the risks of treatment. This article considers the developments in service provision that will probably be required to support the changes in clinical practice suggested by the trials' results. These services will be provided largely by doctors, and their development has implications for doctors in both primary and secondary care.

Recent trials have shown that treatment with warfarin significantly reduces the incidence of stroke among patients with non-valvar atrial fibrillation, and there have been calls for increased use of anticoagulant drugs in such patients.1 2 3 4 5 6 However, while it has considerable potential for preventing stroke, a large increase in warfarin treatment would have knock on effects for diagnostic, investigative, and therapeutic services. The effectiveness of anticoagulant treatment for atrial fibrillation depends on the quality of services provided; without appropriate changes in provision, wide adoption of prophylaxis with anticoagulant drugs could produce more harm than benefit.

Factors that will influence the service needs include the criteria for selection of patients, patient choice, requirements for monitoring and follow up, prevalence of atrial fibrillation, and prevalence of relative and absolute contraindications to anticoagulant treatment. Much information on the quality of services required can be derived from careful examination of the above trials and their applicability to patients receiving routine services. Considerable further work is …