Hyperthyroid-induced atrial flutter-fibrillation with profound sinoatrial nodal pauses due to small doses of digoxin, verapamil, and propranolol.

Atrial fibrillation due to hyperthyroidism is characterized by a rapid ventricular response which is typically resistant to digoxin therapy. We report a patient with atrial flutter-fibrillation who developed cyclic sinus node dysfunction with profound ventricular pauses in response to small doses of digoxin, verapamil, and propranolol, which resolved with discontinuation of the medications. Caution is necessary to avoid paradoxical ventricular slowing when treating hyperthyroid-induced atrial fibrillation.