[Thyroid function in patients during long-term treatment with amiodarone].
Thyroid function was evaluated in 31 patients with disturbances of heart rhythm both before and after 13 months of treatment with amiodarone. An increase in blood serum T4 concentration and transient increase (only during the first three months of treatment) in TSH concentration have been observed in almost all the patients studied. Clinically evident form of hyperthyroidism was found only in one female patient. In two patients the changes in hormone concentrations suggesting hyperthyroidism were not accompanied by clinical manifestations, and in four patients there was no clinical hypothyroidism despite hormone levels suggesting such a state. In addition to the determinations of T3, T4 and TSH also the results of TRH-TSH test played an important role in diagnosing both hypo- and hyperthyroidism.