Cardiac Autonomic Regulation Is Disturbed in Children with Euthyroid Hashimoto Thyroiditis

• Published in: The Tohoku Journal of Experimental Medicine Vol. 226; no. 3; pp. 191 - 195
• Main Authors: Kilic, Ayhan, Gulgun, Mustafa, Tascilar, Mehmet Emre, Sari, Erkan, Yokusoglu, Mehmet
• Format: Journal Article
• Language: English
• Published: Japan Tohoku University Medical Press 01-03-2012
• Subjects: Adolescent; Autonomic Nervous System - physiology; Autonomic Nervous System - physiopathology; cardiac autonomic regulation; Cardiovascular Physiological Phenomena; cardiovascular risk; Child; euthyroid; Female; Hashimoto Disease - physiopathology; Hashimoto thyroiditis; Heart - physiology; heart rate variability; Humans; Male; Retrospective Studies; Thyroid Hormones - blood
• ISSN: 0040-8727; 1349-3329
• DOI: 10.1620/tjem.226.191

Hashimoto thyroiditis (chronic autoimmune thyroiditis) is the most common form of thyroiditis in childhood. Previous studies have found autonomic dysfunction of varying magnitude in patients with autoimmune diseases, which is considered a cardiovascular risk factor. We aimed to evaluate the heart rate variability (HRV), a measure of cardiac autonomic modulation, in children with euthyroid Hashimoto thyroiditis (eHT). The study included 32 patients with eHT (27 girls and 5 boys; mean age 11 ± 4.1 years, range 8-16; body mass index 0.47 ± 0.69 kg/m2), as judged by normal or minimally elevated serum TSH levels (normal range: 0.34-5.6 mIU/l) and normal levels of free thyroid hormones (FT4 and FT3) and 38 euthyroid age-matched controls. Patients with eHT and control subjects underwent physical examination and 24-hour ambulatory ECG monitoring. Time-domain parameters of HRV were evaluated for cardiac autonomic functions. Children with eHT displayed significantly lower values of time-domain parameters of SDANN (standard deviation of the averages of NN intervals), RMSSD (square root of the mean of the sum of the squares of differences between adjacent NN intervals), NN50 counts (number of pairs of adjacent NN intervals differing by more than 50 ms) and PNN50 (NN50 count divided by the total number of all NN intervals) for each 5-min interval, compared to healthy controls (p < 0.05 for each), indicating the decreased beat-to-beat variation of heart rate. In conclusion, eHT is associated with disturbed autonomic regulation of heart rate. Hence, the children with eHT are at higher risk for developing cardiovascular diseases.