Objective To discuss the clinical significance of the changes in heart rate variability (HRV) and deceleration capacity (DC) of heart rate among children with viral myocarditis. Methods Fifty-six cases of preschoolers with viral myocarditis in study group and 58 normal children in control group were examined using 24 hours ECC Holter recording. Heart rate variability (HRV) and deceleration capacity (DC) of heart rate were analyzed by DMS Holter analysis system. The correlation between DC and other indicators was analyzed by nonparametric statistics. Results HRV time-domain parameters including the standard deviation of normal sinus RR intervals (SDNN), the average standard deviation of normal sinus RR interval (SDANN) every 5 minutes, the root mean square of RR interval (RMSSD) , and the low-frequency power (LF) of frequency-domain analysis were not significantly different between children with viral myocarditis and normal children (P > 0.05). The high-frequency power ( HF) was significantly lower in study group (P<0.05). Furthermore, there was a significant difference (P<0.01) in deceleration capacity (DC) of heart rate between two groups. Correlation analysis showed that DC was positively correlated with SDNN, LF and HF, and the strongest correlation existed between DC and HF (r = 0.51, P < 0.01). Conclusions HF and DC, the indications of the vagus nerve functions were significantly decreased. Moreover HF and DC were significantly correlated. It is suggested that there is vagus nerve damage in children with viral myocarditis.%目的 探讨病毒性心肌炎患儿心率变异性(HRV)与心率减速力(DC)各项指标变化的临床意义.方法 对56例病毒性心肌炎患儿与58例正常对照儿童进行24h动态心电图检查,应用美国DMS公司的动态心电分析系统软件,对HRV及DC各项参数进行分析对比；并分析DC与其他各项指标之间的相关性.结果 与正常对照儿童比较,病毒性心肌炎患儿时域分析的各项参数包括正常窦性RR间期的标准差(SDNN)、每5 min时段内平均正常窦性RR间期的标准差(SDANN)、全程RR间期差的均方根(RMSSD)及频域分析的低频功率(LF)的差异均无统计学意义(P＞0.05),而高频功率(HF)显著减低,差异有统计学意义(P＜0.05),且DC显著减低,差异有统计学意义(P＜0.01).相关性分析中,DC与SDNN、LF、HF均成正相关,其中与HF的相关性最强(r=0.51,P＜0.01).结论病毒性心肌炎患儿存在迷走神经功能受损,心率变异性中的HF与DC反映迷走神经功能的指标均显著降低,且两者具有很大相关性.
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