Atrial fibrillation stroke risk

FIGURE 6-9. Decision algorithm for stroke prevention in atrial fibrillation.27 Risk factors for stroke prior transient ischemic attack or stroke hypertension heart failure rheumatic heart valve disease prosthetic heart valve. Target International Normalized Ratio = 2.5 (range 2 to 3). 

Zabalgoitia M, et al. Transesophageal echocardiographic correlates of clinical risk of thromboembolism in nonvalvular atrial fibrillation. Stroke Prevention in Atrial Fibrillation III Investigators. J Am Coll Cardiol 1998 3 I (7) 1622-1626. 

Atrial Fibrillation Investigators. Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation Analysis of pooled data from five randomized controlled trials. Arch Intern Med 1994 154 1449— 1457. 

Wolf PA, Dawber TR, Thomas HE Jr, Kannel WB. Epidemiologic assessment of chronic atrial fibrillation and risk of stroke the Framingham study. Neurology 1978 28 973-7. 

Stroke Prevention in Atrial Fibrillation Investigators. Adjusted-dose warfarin versus low-in-tensity, fixed dose warfarin plus aspirin for high-risk patients with atrial fibrillation Stroke Prevention in Atrial Fibrillation III randomised clinical ttial. Lancet (1996) 348, 633-8,... 

Atrial fibrillation leads to the development of HF, as a result of tachycardia-induced cardiomyopathy.25 Atrial fibrillation increases the risk of mortality approximately two-fold compared to that in patients without AF 23 the causes of death are likely stroke or HF. 

The electrocardiogram will determine whether the patient has atrial fibrillation, which is a major risk factor for stroke. 

The SPAF III Writing Committee for the Stroke Prevention in Atrial Fibrillation Investigators. Patients with nonvalvular atrial fibrillation at low risk of stroke dur-... 

Restoration of sinus rhythm in atrial fibrillation may dislodge thrombi that have developed as a result of stasis in the enlarged left atrium. The risk of stroke and systemic arterial embolism is decreased by anticoagulation in such patients. 

Wolf PA, Abbott RD, Kannel WB. (1991) Atrial fibrillation as an independent risk factor for stroke the Framingham Study. Stroke 11, 983-8. 

Poller, L. and F.R.C. Path The Effect of Low Dose Warfarin on the Risk of Stroke in Patients with Nonrheumatic Atrial Fibrillation, New Eng J. Med.. 129 (July 1L 1992),... 

More than 50% of patients with cerebral embolism have atrial fibrillation. In the majority of these patients, the underlying cardiac disease is nonvalvular. The risk of ischemic stroke and atrial fibrillation increases with age, reaching a cumulative risk of 35% during a patient s lifetime. Combined results from several randomized trials show that warfarin reduces the risk of stroke in patients with nonrheumatic atrial fibrillation by 68% (to 1.4% per year), with an excess incidence of major hemorrhage (including intracranial) of only 0.3% per year. 

Atrial fibrillation is increasing in incidence in developed countries and, because of the risk of embolic stroke, most patients require continuous anticoagulation. A large number of patients with atrial fibrillation are currently treated with vitamin K antagonists. Results of clinical trials in patients with atrial fibrillation indicate that oral direct TIs may become potential drugs for the prevention of embolic stroke and may replace warfarin (62,78,79-81). 

Ostermayer SH, Reisman M, Kramer PH, et al. Percutaneous left atrial appendage transcatheter occlusion (PLAATO system) to prevent stroke in high-risk patients with non-rheumatic atrial fibrillation Results from the international multi-center feasibility trials. J Am Coll Cardiol 2005 46( I ) 9-14. 

P-Blockers are the drugs of choice in atrial fibrillation because they decrease heart rate and promote conversion to sinus rhythm. Longterm, low-dose anticoagulant therapy reduces the risk of stroke that Is associated with atriai fibrillation. 

The overall risk of stroke should be assessed for each individual with atrial fibrillation. It should also be reassessed regularly, as a person s risk of stroke will change over time. The individual s attitude to anticoagulation will strongly influence the cost/benefit of treatment, and should always be taken into account. 

Rhythm control is not recommended as first line treatment in older people with persistent AF and all patients with permanent AF, as rate control would be the preferred treatment. If a patient requires rhythm control, referral to a specialist is recommended rather than commencing in primary care. At least one meta-analysis has shown that, in people with atrial fibrillation at moderate to high risk of stroke, survival rates were similar for rate control or rhythm control. 

CKS recommends that antithrombotic treatment is indicated in all people with atrial fibrillation (AF). The choice of treatment should be determined by the person s risk of stroke. CKS uses the risk stratification recommended by NICE see Table A17.4. 

Paroxysmal atrial fibrillation carries the same stroke risk as persistent atrial fibrillation (Lip and Hee 2001 Saxonhouse and Curtis 2003) and should be treated similarly. There is no evidence that conversion to sinus rhythm followed by pharmacotherapy to try to maintain such rhythm is superior to rate control in terms of mortality and stroke risk (Segal et al. 2001 Blackshear and Safford 2003 Hart et al. 2003). 

Some of the association between atrial fibrillation and stroke must be coincidental because atrial fibrillation can be caused by coronary and hypertensive heart disease, both of which may be associated with atheromatous disease or primary intracerebral hemorrhage. Although anticoagulation markedly reduces the risk of first or recurrent stroke, this is not necessarily evidence for causality because this treatment may be working in other ways, such as by inhibiting artery-to-artery embolism, although trials of warfarin in secondary prevention of stroke in sinus rhythm have shown no benefit over aspirin (Ch. 24). 

Strachan DP, Carrington D, Mendall MA et al. (1999). Relation of Chlamydia pneumoniae serology to mortality and incidence of ischemic heart disease over 13 years in the Caerphilly Prospective Heart Disease Study. British Medical Journal 318 1035-1039 Stroke Prevention in Atrial Fibrillation Investigators (1992). Predictors of thromboembolism in atrial fibrillation II Echocardiographic features of patients at risk. Annals of Internal Medicine 116 6-12 Stroke Prevention in Atrial Fibrillation Investigators (1995). Risk factors for thromboembolism during aspirin therapy in patients with atrial fibrillation the Stroke Prevention in Atrial Fibrillation Study. Journal of Stroke and Cerebrovascular Disease 5 147-157... 

Mitral leaflet prolapse is a common incidental finding. It can be complicated by gross mitral regurgitation, infective endocarditis, atrial fibrillation and left atrial thrombus and thus embolism to the brain. However, there is no excess risk of first or recurrent stroke in patients with uncomplicated mitral leaflet prolapse (Orencia et al. 1995a, b). 

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