[The effect of pharmacologic therapy of hyperthyroidism on automatic heart conduction]

Investigations of the heart automatism were carried out in 10 patients with hyperthyreoidism before thiamazol therapy and after restoration of the euthyroid status. A control group was comprised of 34 healthy subjects. In order to determine the electrophysiologic parameters the transoesophageal atrium extrastimulus technique and the over-driving stimulation were applied. Restoration of the euthyroid status was accompanied by a significant prolongation of the atrial refraction, the border interval, the border conductivity and the sinus rhythm recurrence time. In a half of the patients were atrioventricular and intraventricular conductibility disturbances observed. The authors conclude, that in the early period of the euthyroid status restoration after thiamazole therapy there still exists a risk of cardiologic complications.