Valvular atrial fibrillation, defined as AF with mechanical valves or rheumatic valvular disease, requires which anticoagulant?

• A. DOACs
• B. Warfarin
• C. Aspirin
• D. Heparin

Answer: (B)

In valvular atrial fibrillation, the presence of a mechanical heart valve or rheumatic valvular disease creates a high risk of thromboembolism that requires a longstanding, proven anticoagulant. Direct oral anticoagulants are not used in this setting because they have not shown safety and effectiveness for mechanical valves or significant rheumatic valve disease; in fact, studies have shown worse outcomes with DOACs in mechanical valves and they are generally not recommended for this group. Warfarin, a vitamin K antagonist, has long been the standard because it provides reliable, controllable anticoagulation that protects against stroke and valve-related thrombosis when the target INR range is maintained. It requires regular blood monitoring to keep therapy within that range.

Aspirin alone does not provide adequate stroke prevention in AF with valvular disease, though it may be used in some low-risk situations or for other indications. Heparin is useful for short-term acute management or peri-procedural bridging, not as long-term therapy for-valve AF.