[The specific features of hypothyroidism developing with the use of cordorone]

Hypothyroidism (HT) is one of the thyroid dysfunctions occurring with the use ofcordorone. The authors examined the clinical features of this condition in 26 patients living in Moscow and its region (mild and moderate iodine deficiency areas). The blood levels of thyrotropic hormone (TTH), free thyroxine (Т4) free triiodothyronine (T3), thyroid peroxidase antibodies, and lipid spectrum were estimated. Thyroid ultrasound study and Holler ECG monitoring were performed. HT was found to develop in the presence of the abnormally changed (66%) and intact (34%) thyroid. Examining the course of cardiac arrhythmias (CA) as HT progresses has ascertained that this condition does not lead to their recurrences. As compared with the controls, the patients were found to have higher frequencies of dyslipidemias (p < 0.05). Blood lipid changes appeared as the higher levels of total and LDL cholesterol (p < 0.05); a positive correlation was also established between these parameters and the levels of TTH. The use of L-thyroxine replacement therapy, as indicated on an individual basis, during ongoing cordorone intake did not result in relapses of prior CA and it contributed to blood lipid spectrum parameters. Thus, HT is a condition that does not cause a loss of the antiarrhythmic effects ofcordarone manifests itself as the impaired blood lipid spectrum. L-thyroxine replacement therapy may be, if required, performed during the ongoing use of an antiarrhythmic agent.