Amiodarone and Early Antithyroid Therapy Section for Drug-refractory Atrial Fibrillation in Thyroid Storm: A Case Report

Thyroid storm classically presents with fever, agitation and gastrointestinal disturbance. Occasionally, however, it may manifest solely as drug-refractory tachyarrhythmia, creating a diagnostic and therapeutic challenge when beta-blockade, the standard rate-control agent, is contraindicated. The present report describes a 71-year-old male with computed-tomography-confirmed obstructive lung disease who presented with atrial fibrillation at 140 beats per minute that failed adenosine and intravenous diltiazem. A Burch-Wartofsky score of 45, calculated at the bedside before thyroid biochemistry was available, was diagnostic of thyroid storm and justified empirical management. Beta-blockade was withheld because of the patient’s fibrotic, obstructive lung disease and intravenous amiodarone was used instead, achieving rate control within 30-40 minutes. When the amiodarone infusion was discontinued, however, the ventricular rate rebounded immediately to 110-130 beats per minute, demonstrating that the underlying thyrotoxic substrate persisted despite adequate atrioventricular nodal blockade. Biochemistry subsequently confirmed thyrotoxicosis (thyroid-stimulating hormone <0.01 mIU/L; free thyroxine 4.2 ng/dL; free triiodothyronine 11.1 pmol/L). Amiodarone was restarted with concurrent initiation of carbimazole 40 mg/day, after which durable rate control was achieved and maintained to discharge on Day 7. The present case is notable for demonstrating, through a reproducible bedside rebound phenomenon, that amiodarone monotherapy for thyroid-storm-associated atrial fibrillation is only a temporising measure and that antithyroid therapy must be initiated alongside rate control rather than sequentially, guided by clinical scoring rather than delayed for biochemical confirmation.