Atrial Fibrillation Anticoagulation

Atrial fibrillation (AF) removes the atria’s effective contraction. Blood can pool in the left atrium, especially the left atrial appendage, where stasis supports thrombus formation and systemic embolization. The clinical consequence may be a large, disabling cardioembolic stroke even when the patient has little awareness of the arrhythmia. For a Canadian NP, the anticoagulation decision begins with CHADS-65, not with CHA₂DS₂-VASc. Age 65 years or older is itself an indication for oral anticoagulation in a patient with AF or atrial flutter. Below age 65, anticoagulation is indicated when at least one CHADS₂ risk factor is present. The rhythm may be paroxysmal, persistent, or permanent; the stroke-prevention decision is based on the patient’s risk burden rather than how often symptoms occur. This distinction matters because international resources may display different thresholds. CHA₂DS₂-VASc remains useful for understanding US and other non-Canadian guidance, but its sex-specific treatment thresholds should not be imported into Canadian practice. The medication decision must then be matched to valve anatomy, kidney function, bleeding hazards, interactions, adherence, and the timing of cardioversion or procedures.