Endocrine Abstracts

Background: We aimed prospectively investigate the laboratory and electrocardiographic parameters (hearth rate, QRS, QT, QTc, Tpe, Tpe/QTc, arrhythmia prevalance) in patients with graves disease before and after antithyroid therapy.

Methods: 71 patients (48 female, 23 male), age between 18–50 (mean ± s.d.: 36.48 ± 12.20) with GD were included into the study. Patients treated with antithyroid therapy (thionamids and/or surgical therapy) to maintain euthyroid status. Patients were examined in terms of electrocardiographic parameters before and after the treatment.

Results: Mean TSH, free thyroxin (fT₄) and tri-iodothyrionine (fT₃) levels of all patients were 0.005 ± 0.21, 3.27 ± 1.81, 11.42 ± 7.44, respectively. While 9 patients (group 2) underwent surgical therapy, had suspicious of malignant nodule or large goiter and unresponsiveness to medical treatment; the other patients (n = 62, group 1) were treated with medical therapy. Patients with surgical therapy had more increased serum fT4 (P = 0.045), anti-thyroglobulin value (P = 0.018) and more severe graves orbitopathy (n = 0.051) before treatment when compared to medical therapy group. Baseline Tpe duration and baseline Tpe/QTc ratio and frequency of supraventricular ectopic beats were found to be significantly higher in group 2 when compared to group 1 (P = 0.00, P = 0.005). Otherwise baseline mean heart rate, QRS duration, QTc values of both groups were similar. Although the patients became their euthyroid status, group 2 patients had still suffered from more sustained supraventricular ectopics beats than group 1.

Conclusions: Distinct from medical treatment group, surgical treatment group with euthyroidism at least 3 months had still suffered from an arrhythmia (Tpe, Tpe/QTc, supraventricular and ventricular ectopic beats).