Management of Atrial Fibrillation in Hyperthyroidism
Introduction to Atrial Fibrillation Management
- The European Heart Journal recommends that oral anticoagulation with a target INR of 2.0-3.0 should be initiated immediately in patients with atrial fibrillation associated with hyperthyroidism to prevent thromboembolism 4.
- The American College of Cardiology suggests that beta-blockers are the first-line therapy for rate control in atrial fibrillation complicating hyperthyroidism, with metoprolol 25-50 mg PO every 6-8 hours or atenolol 25-50 mg PO daily being suitable options 2, 3, 4, 5.
Diagnosis and Assessment
- Hyperthyroidism causes atrial fibrillation in 10-25% of patients, more commonly in men and the elderly, according to the European Heart Journal 4.
- The American College of Cardiology states that a suppressed TSH level (<0.1) is diagnostic of a hyperthyroid state, and requires confirmation with elevated Free T4 and Free T3 levels 4, 5, 6.
Treatment and Management
- The European Heart Journal recommends that treatment of atrial fibrillation in hyperthyroidism is primarily directed toward restoring the euthyroid state, which usually results in spontaneous reversion to sinus rhythm 4.
- The American College of Cardiology suggests that anticoagulation should not be deferred until after cardioversion or achievement of the euthyroid state, and that anticoagulation is the only therapy proven to reduce atrial fibrillation-related deaths 4, 5, 7.
- The European Heart Journal states that paroxysmal atrial fibrillation carries the same stroke risk as permanent atrial fibrillation, and that anticoagulation should be continued based on stroke risk factors even after sinus rhythm is restored 8, 9.