Which statement is true regarding anticoagulation in atrial fibrillation?

• A. Warfarin is preferred for valvular atrial fibrillation
• B. Dabigatran is preferred for valvular atrial fibrillation
• C. Rivaroxaban is contraindicated in valvular atrial fibrillation
• D. Aspirin alone is preferred in valvular atrial fibrillation

Answer: (A)

In atrial fibrillation, stroke prevention hinges on whether the valve situation is considered valvular disease (such as a mechanical heart valve or moderate-to-severe rheumatic mitral stenosis) or nonvalvular. For true valvular AF, warfarin is the preferred anticoagulant because it has proven efficacy in this specific group and its effect can be closely monitored and adjusted via the INR. Direct oral anticoagulants (dabigatran, rivaroxaban, apixaban, edoxaban) have not demonstrated the same safety and effectiveness in patients with mechanical valves or significant rheumatic valve disease, so they are not used in that setting. Aspirin alone is generally insufficient for preventing stroke in AF, especially when valvular disease is present. Therefore, warfarin remains the best answer for valvular atrial fibrillation.