The relationship between the TSH values and the tpeak - tend i̇nterval duration in hypothyroid patients receiving levothyroxine treatment

Aim: The cardiovascular system can be affected by changes in thyroid hormone levels. The cardiac affect of hypothyroidism is involve sinus bradycardia, low-voltage QRS complexes, and prolonged QT interval. The prolonged Tp-Te and QTc interval durations in patients with hypothyroidism reflect the risk of arrhythmia with prolonged ventricular repolarization. The Tpeak-Tend (Tp-Te) interval is a new and strong marker of ventricular arrythmia. The aim of this study was to investigate for the first time in literature how the Tp-Te interval is affected in hypothyroid patients receiving levothyroxine (LT-4) treatment. Material and Method: A total of 119 people between the ages of 18-45 were included in the study. This prospective, case-control study included 81 female patients who presented for treatment and follow-up at the Internal Medicine Outpatient Clinic of Adiyaman University Medical Faculty Hospital. The patient groups comprised 42 patients in the euthyroid group, 39 in the hypothyroid group. A control group was performed of 38 healthy females not determined with hypothyroid. The QTc and Tp-Te interval were recorded manually on precordial leads based on the ECG record on first presentation. Results: In the hypothyroid group, the Tp-Te and QTc intervals measured were determined to be significantly longer than those of the euthyroid group and the control group. A positive correlation was determined between the TSH levels and the Tp-Te and QTc intervals. In the regression model including the Tp-Te and QTc, both parameters were determined to be independent predictors of hypothyroidism. The diagnostic value of Tp-Te, was determined to be greater than QTc. Conclusion: Ventricular homogeneity, and therefore the Tp-Te interval, is affected by primary hypothyroidism and it can be considered that a sufficient dose of LT-4 replacement therapy could reduce malignant ventricular arrhythmia and suddenc cardiac death.