Amiodarone-associated thyreopathy in children with arrhythmias

Aim: To assess the indices of hormonal thyroid state during prolonged amiodarone therapy in children with arrhythmias at the ages from 0 to 7 years. 42 patients with WPW syndrome (n=19), atrial tachycardias (n=16), and ventricular tachycardias (n=7) received amiodarone therapy. The duration of amiodarone intake varied from 0.7 to 24 months (Me 6.00; IQR 1.83-9.00). The course of thyroid state was assessed in the following sequence: initially, during the prolonged treatment by amiodarone, but not earlier than in a month after the therapy started, and in 6 months after amiodarone withdrawal. Increases in thyroid stimulating hormone (TSH), thyroxine (total and free), and thyroglobulin as well as moderate decrease in triiodothyronine were demonstrated in the presence of amiodarone. The increases in total and free thyroxine (p=0.043 and p=0.037 correspondingly) were statistically significant. Statistically insignificant was the increase of TSH and thyroglobulin on amiodarone therapy. However, the decreases in the given indices were significant (p=0.006 and p=0.036 correspondingly) 6 months after amiodarone withdrawal. The comparison of initial indices with the results of their analysis 6 months after amiodarone withdrawal did not show any statistically significant differences. It should be noted that the clinical sings accompanying hypertyrosinemia during amiodarone therapy were not observed in our patients. The most significant changes of the thyroid state were discovered in infants. It should be noted that, the median indices did not go beyond reference range at all stages of amiodarone treatment including also their statistically significant changes at the peak of the therapy. Amiodarone-induced changes of thyroid state were of reversible nature and normalized 6 months after the therapy withdrawal.