Can amiodarone be given to a patient with thyroid storm and atrial fibrillation (AFib) in rapid ventricular response (RVR) with a heart rate of 200 beats per minute (tachycardia)?

Management of Atrial Fibrillation with Rapid Ventricular Response in Thyroid Storm

Amiodarone should NOT be given to patients with thyroid storm who have atrial fibrillation with rapid ventricular response, as it can worsen thyrotoxicosis and potentially create a dangerous cycle of worsening thyroid dysfunction and arrhythmias. 1, 2

First-Line Management Options for AFib with RVR in Thyroid Storm

• For hemodynamically unstable patients with AFib and RVR at 200 bpm, immediate electrical cardioversion is recommended 3

• In hemodynamically stable patients with thyroid storm and AFib with RVR, beta-blockers are the first-line treatment to control ventricular rate, unless contraindicated 3

• If beta-blockers are contraindicated, a non-dihydropyridine calcium channel antagonist (diltiazem or verapamil) can be used to control ventricular rate 3

• In the absence of pre-excitation, IV digoxin can be considered for acute heart rate control when beta-blockers or calcium channel blockers are contraindicated 3

Why Amiodarone is Contraindicated in Thyroid Storm

• Amiodarone contains high amounts of iodine (37% by weight) that can exacerbate thyrotoxicosis in patients with thyroid storm 4

• Amiodarone can cause both hypothyroidism and hyperthyroidism due to its effects on thyroid function and metabolism 5

• Amiodarone-induced thyrotoxicosis can lead to life-threatening ventricular arrhythmias and worsen the existing thyroid storm 1, 6

• There are documented cases of amiodarone administration causing thyroid storm and sustained monomorphic ventricular tachycardia 1

Alternative Management Strategies

• For patients with thyroid storm and AFib with RVR, treatment should focus on:

  • Controlling thyrotoxicosis with thionamides (methimazole or propylthiouracil) 7
  • Rate control with beta-blockers (preferably propranolol due to its additional T4 to T3 conversion blocking properties) 3
  • Supportive care including cooling measures, fluid resuscitation, and glucocorticoids 7

• In cases where medical therapy is insufficient to control rate:

  • AV node ablation with ventricular pacing may be considered as a salvage therapy 3, 2
  • Plasmapheresis has been reported as an effective treatment option in refractory cases 1

Monitoring and Follow-up

• Regular monitoring of thyroid function tests is essential for patients receiving any antiarrhythmic therapy 7

• Once the thyroid storm is controlled, reassessment of the cardiac rhythm and rate control strategy should be performed 6

• Long-term management should include definitive treatment of the underlying thyroid disorder to prevent recurrence 7

Special Considerations

• The decision to use any antiarrhythmic medication in thyroid storm should be made in consultation with both cardiology and endocrinology specialists 7

• In cases of extreme hemodynamic compromise despite conventional therapy, emergency thyroidectomy may be required 7

• For patients previously on amiodarone who develop thyroid storm, the drug should be discontinued and alternative antiarrhythmic strategies employed 2, 6