Circadian change of autonomic nervous system in hyperthyroidism patients / 中国医师进修杂志

ABSTRACT

Objective To investigate the circadian change of autonomic nervous system in hyperthyroidism (HT) patients. Methods Recording 24 h dynamic electrocardiography from 33 HT patients( HT group) and 35 controls (control group). The cardiac autonomic nervous function was evaluated by the time domain and frequency domain analysis of heart rate variability( HRV). Results Comparing with control group, the SDNN, SDANN, ASDNN and rMSSD were significantly lower in HT group[ (82.3 ± 29.0)ms vs. (139.4±40.2 ) ms, ( 75.0 ± 27.4) ms vs. ( 130.3 ± 43.9) ms, (29.9 ± 14.9 ) ms vs. (57.3 ± 14.4) ms,( 19.8 ± 10.9 ) ms vs. (29.5 ± 9.4) ms ] (P ＜ 0.01 or ＜ 0.05 ), the long term total power (TP), high frequency (HF), low frequency (LF) and very low frequency (VLF) were significantly lower in HT group [ (566.1±573.2) ms2/Hz vs. ( 1894.2 ± 984.3)ms2/Hz, (68.1 ± 88.9 ) ms2/Hz vs. (232.7 ± 155.5 ) ms2/Hz, ( 127.4 ±163.0) ms2/Hz vs. (551.3 ± 390.6) ms2/Hz, (330.3 ± 300.6) ms2/Hz vs. (1073.2 ± 570.2) ms2/Hz] (P ＜0.01 ). Comparing with control group, short term VLF was higher in HT group during most time in 24 hours (P＜ 0.05 ). Short term LF was higher in HT group mainly in day time (P＜ 0.05 ). Short term HF was higher in HT group occasionally in the whole day (P＜0.05). Short term LF/HF didn't show significant difference between HT group and control group at most time points (P＞0.05).Conclusion In HT patients, cardiac chronotropic property is impaired, sympathetic activity increases in whole day, vagal activity increases correspondently but the increase in day is more marked than that in night.