Disease overview – Stroke prevention in atrial fibrillation
Professor David Fitzmaurice
Primary Care Clinical Sciences, The University of Birmingham, Edgbaston, Birmingham, UK
Atrial fibrillation is an independent risk factor for stroke, even in the absence of mitral valve disease (non-rheumatic atrial fibrillation). The relative risk for stroke associated with Non-Rheumatic Atrial Fibrillation (NRAF) must be of primary consideration, given that oral anticoagulation carries its own risks. In clinical practice it is safest to assume that the risk of stroke is constant between paroxysmal and persistent or permanent atrial fibrillation. Overall community prevalence has been estimated at 1.2% in the UK. Approximately 50% of patients with AF are 75 or over and over half of these are women. In general practice the single most important investigation in a patient suspected of having AF is electrocardiography. An ambulatory24 h ECG may be necessary and on occasion we may need to use a 3-day, or even a 7-day, event monitor. The changes on the ECG are very characteristic in AF. Blood tests in primary care should include a full blood count and a baseline INR. Other tests such as thyroid/liver/renal function (including proteinuria) may be undertaken depending on clinical assessment. Further cardiac investigations require referral to secondary care. New and novel therapies which hope to overcome the problems of initiating, monitoring, interaction and complication of current anticoagulation therapy are under investigation, such as the direct thrombin inhibitors and factor Xa inhibitors. Findings from the landmark RE-LY study are promising and suggest dabigatran may be an effective alternative to warfarin in stroke prevention. The introduction of newer agents is likely to change the landscape of anticoagulation use in AF patients and it will be interesting to see the effect of increasing treatment options for these patients over the next few years.