Aktar Ulukapi Nilay, Kirel Birgul, Kiztanir Hikmet, Sulu Ayse, Kosger Pelin, Ozen Hulya, Ucar Birsen
Eskişehir Osmangazi University Faculty of Medicine, Department of Pediatrics, Eskisehir, Turkey.
Eskişehir Osmangazi University Faculty of Medicine, Department of Pediatric Endocrinology, Eskisehir, Turkey.
Pediatr Res. 2024 Nov 24. doi: 10.1038/s41390-024-03759-3.
Clinical effects of subclinical hypothyroidism are not clearly understood. This study aims to investigate the effects of subclinical hypothyroidism (SH) on cardiac autonomic and conduction systems in children.
Forty-seven cases (25 female, 22 male) with SH aged between 3 and 17 years and 46 controls that were age, body mass index and sex matched, were included in the study. Heart rate variability (HRV) was used to evaluate cardiac autonomic function while QT dispersion, P dispersion and Tp-e measurements from ECGs to evaluate susceptibility to arrhythmia.
Standard deviation of the average of Normal-Normal intervals in 5-minute measurements was lower in the SH group compared to controls. No statistically significant differences were found in other time or frequency domain parameters. Maximum and minimum corrected QT intervals were longer in the SH group (p = 0.047 and p = 0.012, respectively); there were no significant differences in other ECG parameters.
Our study demonstrates that cardiac autonomic dysfunction and arrhyhtmogenesis shown as susceptibility to ventricular arrhythmia and longer intraatrial conduction times, appear in children with SH.
To our knowledge, this is the first study to show changes in cardiac autonomic function using heart rate variability in children with subclinical hypothyroidism (SH). We suppose that the fact that ventricular repolarization is longer in children with SH regardless of heart rate shows a predisposition to ventricular arrhythmia. Our study demonstrates that cardiac autonomic dysfunction and arrhythmogenesis shown as susceptibility to ventricular arrhythmia and longer intraatrial conduction times, appear in children with SH. We suggest that an evaluation regarding arrhythymia together with endocrinological follow-up is warranted when children are diagnosed with SH.
亚临床甲状腺功能减退的临床影响尚不清楚。本研究旨在探讨亚临床甲状腺功能减退（SH）对儿童心脏自主神经和传导系统的影响。
本研究纳入了47例年龄在3至17岁之间的SH患儿（25例女性，22例男性）以及46例年龄、体重指数和性别相匹配的对照儿童。采用心率变异性（HRV）评估心脏自主神经功能，同时通过心电图测量QT离散度、P波离散度和Tp-e间期来评估心律失常易感性。
与对照组相比，SH组5分钟测量的正常RR间期平均值的标准差较低。在其他时域或频域参数方面未发现统计学显著差异。SH组的最大和最小校正QT间期较长（分别为p = 0.047和p = 0.012）；其他心电图参数无显著差异。
我们的研究表明，SH患儿存在心脏自主神经功能障碍和心律失常发生，表现为室性心律失常易感性和心房内传导时间延长。
据我们所知，这是第一项利用心率变异性显示亚临床甲状腺功能减退（SH）患儿心脏自主神经功能变化的研究。我们推测，SH患儿无论心率如何，其心室复极化时间较长这一事实表明其存在室性心律失常倾向。我们的研究表明SH患儿存在心脏自主神经功能障碍和心律失常发生，表现为室性心律失常易感性和心房内传导时间延长。我们建议，当儿童被诊断为SH时，除了进行内分泌随访外，还应进行心律失常评估。
