Delayed Presentation of Amiodarone Induced Thyrotoxicosis Following Heart Transplant

Abstract

Introduction: Amiodarone is commonlyused in the advanced heart failure population for treatment of arrhythmias. Three to five percent of patients treatedwith amiodarone develop hyperthyroidism, most commonly Type II Amiodarone Induced Thyrotoxicosis (AIT) from destructive thyroiditis. There is little data available evaluating the prevalence of AIT in the transplant population or relatedmorbidity andmortality.Case Series: Approximately half of the patients transplanted at our center are treated with amiodarone prior to cardiac transplant. In the last 20 years, 87 patients received amiodarone prior to or immediately post transplant, and 5 patients developed thyroiditis following transplant (5.7 %). Four patients were treated with amiodarone for an average of 1.6 years prior to transplant, then discontinued at the time of transplant. One patient started amiodarone 5 days after transplant for atrial fibrillation and continued for1.8years.Onaverage, thyroid dysfunction was diagnosed 366 days after discontinuation of amiodarone. The mechanism of dysfunction was thought to be thyroiditis in each patient. Two patients underwent coronary angiography around the time of their diagnosis, so the iodine load may have contributed to an iodine induced thyrotoxicosis in addition to amiodarone. Patients received steroids as part