Clinical analysis of heart rate variability in patients with thyroid disfunction / 中国地方病学杂志

ABSTRACT

Objective To investigate the autonomic nervous system function of hyperthyroidism and hyperthyroidism by analyzing the heart rate variability of patients with the diseases. Methods 12-synchronous dynamic 24-hour monitoring and man-machine dialogue were used in 36 patients with hyperthyroidism, 30 patients with hypothyroidism and 26 cases of healthy volunteers(controls), and 24-hour electrocardiogram was analyzed.Heart rate variability indicators observed included 24 h consecutive sinus standard deviation of R-R interval (SDNN), standard deviation of sequential five-minute R-R interval (SDANN), percentage of differences between adjacent NN intervals that ＞ 50 ms(PNN50), root mean square standard deviation from adjacent R-R interval (rMSSD), low-frequency power (LF), high frequency power (HF), low frequency power/high frequency power (LF/HF). Results In hyperthyroidism group, SDNN[(80.48 ± 11.95)ms], PNN50[(18.56 ± 3.50)%], rMSSD [ ( 13.56 ± 3.45)ms] were significantly lower than those of the control group[ ( 128.06 ± 12.8)ms, (32.84 ± 7.21)%,(30.84 ± 6.12)ms, all P ＜ 0.05 ], and LF/HF(3.78 ± 1.63) were significantly higher than that of the control group (2.34 ± 1.06, P ＜ 0.05). In hypothyroidism group, SDNN[(65.65 ± 15.55)ms], SDAN[ (80.2 ± 15.72)ms],PNN50[ (16.34 ± 3.56)%], rMSSD [ (15.77 ± 3.58)ms ], LF[ (279.03 ± 91.49)ms2/Hz ] were also significantly lower than those of the control group[ (128.06 ± 12.87)ms, (132.40 ± 21.95 )ms, (32.84 ± 7.21 )%, (30.84 ± 6.12)ms, (525.60 ± 84.11)ms2/Hz, all P ＜ 0.05], but LF/HF (1.08 ± 0.73) was lower than that of the control group,however, the difference was not significant(P ＞ 0.05). Conclusions The heart rate in patients with abnormal thyroid function is lower in the overall performance, but in patients with hyperthyroidism sympathetic activity is dominate, while in patients with hypothyroidism, vagal nerve activity is dominate.