Management in A Patient with Cardiomyopathy and Thyrotoxicosis: A Challenging Decision

Background: It is not uncommon to encounter a patient with cardiomyopathy and a concomitant thyroid disorder. However, management becomes complex and potentially life-threatening if the patient has an arrhythmia with hypotension. Case: 55-year-old male with a history of nonischemic cardiomyopathy, atrial fibrillation and cocaine use presented with recurrent implanted cardiac defibrillator shocks. On presentation, he was hypotensive with a blood pressure of 88/62. Electrocardiogram showed Atrial Fibrillation with rapid ventricular response with a rate of 144 beats per minute. He was started on amiodarone bolus and transitioned to a drip. He was subsequently found to have thyroxine levels four times the upper limit of normal. His amiodarone was discontinued, and he was started on dofetilide, methimazole, and oral prednisone. After 3 days of treatment, his heart rate remained elevated and borderline hypotensive. He was then started Propranolol with stabilization of his vital signs and discharged home in two days. Conclusion: Initiation of propranolol should be carefully considered in patients with known cardiomyopathy and concurrent thyrotoxicosis. There is high risk of developing cardiogenic shock and potentially even death.