Atrial fibrillation and arterial embolism in hyperthyroidism

Area of Science:

• Cardiology
• Endocrinology

Background:

• Uncontrolled hyperthyroidism frequently causes cardiac arrhythmias, specifically atrial fibrillation or flutter.
• These arrhythmias can lead to significant complications, including arterial embolism.

Purpose of the Study:

• To investigate the incidence of atrial fibrillation/flutter in patients with uncontrolled hyperthyroidism.
• To evaluate the effectiveness of antithyroid and antiarrhythmic treatment on rhythm restoration.
• To identify risk factors for embolism in this patient population.

Main Methods:

• Retrospective analysis of 70 patients with uncontrolled hyperthyroidism and atrial fibrillation/flutter.
• Assessment of rhythm reversion rates with combined antithyroid and antiarrhythmic therapy.
• Evaluation of embolic episodes and associated patient characteristics.

Main Results:

• Atrial fibrillation or flutter occurred in 70 of 381 patients (18.4%).
• 39 patients (55.7%) reverted to sinus rhythm with treatment; one-third reverted within the first week.
• Younger age, recent onset arrhythmia, and absence of heart disease predicted rhythm reversion.
• Eight patients experienced embolic episodes, with five proven and three probable; four died.
• Embolism was associated with atrial fibrillation, cardiac failure, and uncontrolled hyperthyroidism.

Conclusions:

• Antithyroid and antiarrhythmic treatment can restore sinus rhythm in a significant proportion of hyperthyroid patients with atrial fibrillation/flutter.
• Patients with uncontrolled hyperthyroidism and atrial fibrillation/flutter, especially with cardiac failure, are at high risk for embolic events.
• Prophylactic anticoagulation may be warranted in high-risk patients, pending further investigation.