Atrial fibrillation (AF) is a significant cause of stroke. The lack of contractility from the upper chambers of the heart (atria) lead to pooling of the blood with resultant “clot” (thrombus) formation. Should even small elements of these clots disperse, and embolize to the brain: the result is a stroke. The latter can be a catastrophic event in a patient and their families lives. Most often, patients are left with a loss of function speech, vision, cognitive abilities, ability to use an arm, leg etc.
Hence, preventive medicine is the call upon diagnosing AF. Not all patients with AF will develop a stroke; much depends on coexisting risk factors heart failure, vascular disease, diabetes and others. The currently used stroke “prediction” model is known as CHADS2VASC. The latter is a useful tool used to determine higher risk patients who may benefit from “blood thinners,” also known as oral anticoagulants (OA).
The oldest and most widely used OA is warfarin (coumadin). The main advantage of this drug is that nearly all prescribing clinicians have extensive experience with this medication. Moreover, the drug is easily reversed with vitaminK or the transfusion of pooled fresh frozen plasma. The use of this medication requires the patient to be disciplined and compliant with frequent (often monthly) blood testing. The disadvantages are a highly variable patient response to the drug. A decrease in dietary intake, may lead to markedly enhanced blood thinning effect. The consequences may be an increased bleeding predisposition leading to such complications as gastrointestinal bleeding (1).
Warfarin while often very well tolerated may interact negatively with other medications, such as certain antibiotics (e.g. ciprofloxacin) or other cardiac medications (e.g. amiodarone). Many health providers offer inoffice point of care blood tests , with results immediately available to the patient and direction of appropriate dosing. This type of service is invaluable to patients as potentially negative outcomes are anticipated and dealt with. In this context, warfarin has been proven to be very useful and safe in the prevention of stroke. Undertreatment of patients who who would otherwise benefit from anticoagulation have been proven to have worse outcomes (2). The decision to proceed with warfarin is made by a wellinformed patient and their physicians.
- J anuary CT et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2014 Dec 2;64(21):e176
- N ieuwlaat R et al. Guidelineadherent antithrombotic treatment is associated with improved outcomes compared with undertreatment in highrisk patients with atrial fibrillation. The Euro Heart Survey on Atrial Fibrillation. Am Heart J. 2007 Jun;153(6):100612.