Amiodarone induced thyrotoxicosis: diagnostic and therapeutic strategies.

Safety and efficacy of early radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation complicated with amiodarone-induced thyrotoxicosis

“…AIT was diagnosed in patients who had normal thyroid function and after taking amiodarone had a thyroid stimulating hormone (TSH) level < 0.27, free thyroxine (FT4) level > 22, and/or free triiodothyronine (FT3) level > 6.8 (normal values, TSH: 0.27~4.2 IU/mL; FT4: 12.0~22.0 pmol/L; FT3: 3.10~6.80 pmol/L) [6]. Patients with any of the following conditions were excluded from the AIT group: AF found at the same time or after thyrotoxicosis occurrence; evidence of organic thyroid disease in thyroid ultrasound; presence of antithyroid peroxidase (ATPO) antibody and anti-thyroglobulin antibody (TG-Ab); persistent AF; structural heart diseases, such as valvular heart disease and congenital heart disease; and presence of left atrial thrombus in transesophageal echocardiography.…”

Amiodarone-induced thyrotoxicosis: A review

“…IL-6 may be elevated in patients with other coexisting illnesses such as heart failure, nonthyroidal conditions and other thyroid conditions such as Graves' disease (18). Additionally, some patients with type 2 AIT have been reported to have unexpectedly low IL-6 levels, which may be related to the commercial assay used (10). Overall, it is believed that IL-6 testing should be used to follow patients with type 2 AIT who present with significantly elevated levels of IL-6, or have exacerbations during weaning of treatment and in cases of type 1 AIT that recur or fail to respond to treatment.…”

“…The effects of amiodarone on the thyroid can be seen as early as a few weeks after starting treatment and/or up to several months after its discontinuation (10). Because thyroid dysfunction is relatively common in amiodarone therapy, all patients should have free thyroxine and thyroid-stimulating hormone (TSH) levels measured before starting therapy, at three-to four-month intervals during treatment and for at least one year after the amiodarone is discontinued.…”

“…Because thyroid dysfunction is relatively common in amiodarone therapy, all patients should have free thyroxine and thyroid-stimulating hormone (TSH) levels measured before starting therapy, at three-to four-month intervals during treatment and for at least one year after the amiodarone is discontinued. A diagnosis of AIT can also be considered at any time in a patient who develops clinical signs of thyrotoxicosis (Table 1) (10). Cardiac manifestations may be absent due to amiodarone's effect on the heart.…”

Atrial Fibrillation: Focus on New Therapeutic Strategies

“…16,17 More than 50% of patients treated with amiodarone have nonclinical abnormalities of thyroid function manifested by a slightly elevated serum free thyroxine (T4) level, normal or low triiodothyronine (T3) levels, elevated reverse T3 level, or transiently increased or decreased thyroid-stimulating hormone (TSH) concentration. 18,19 Most of the patients with T4, T3, reverse T3, or TSH abnormalities remain clinically euthyroid. In patients with suspected amiodarone-induced thyrotoxicosis, the degree of TSH, T3, and T4 abnormalities together with clinical signs should confirm its presence.…”