Why is anticoagulation used in atrial fibrillation and which agents are common?

• A. To prevent cardioembolic stroke; DOACs and warfarin
• B. To reduce cholesterol; statins
• C. To control heart rate; beta-blockers
• D. To treat chest pain; nitrates

Answer: (A)

Preventing cardioembolic stroke is the main reason to anticoagulate in atrial fibrillation. In AF the irregular, ineffective atrial contractions promote blood pooling and thrombus formation, especially in the left atrial appendage; if a clot breaks off, it can travel to the brain and cause a stroke. Anticoagulants reduce this risk by inhibiting the clotting cascade so new clots form less readily. The most common options are direct oral anticoagulants—apixaban, rivaroxaban, dabigatran, and edoxaban—and warfarin, a vitamin K antagonist. DOACs are often favored for nonvalvular AF because they typically don’t require routine monitoring and have a lower risk of intracranial bleeding, though they require careful use in renal impairment and have specific reversal considerations. Warfarin has a long track record but needs regular INR monitoring and more management of drug and dietary interactions. These agents are used for stroke prevention in AF, whereas antiplatelet therapies like aspirin alone are less effective for this purpose.