不明原因心前区不适患儿心率减速力及心率变异性分析北大核心CSCD

目的：探讨心率减速力（DC）、心率加速力（AC）及心率变异性（HRV）在不明原因心前区不适患儿中的变化。方法56例不明原因心前区不适患儿（患儿组）和63例健康儿童（对照组）,年龄6-17岁,行24h动态心电图检查,并对其DC及HRV各项指标进行对比及相关性分析。结果患儿组的DC值小于对照组,AC值大于对照组,心率（HR）大于对照组,差异有统计学意义（P均〈0.05）;患儿与对照组间HRV指标的差异无统计学意义（P〉0.05）。患儿组中,DC与HRV多项指标呈显著正相关（r=0.27-0.40,P均〈0.05）,与HR呈显著负相关（r=–0.46,P=0.000）;而AC与HRV多项指标呈显著负相关（r=–0.57-–0.34,P均〈0.05）,与HR呈显著正相关（r=0.61,P=0.000）。〈12岁男性患儿HR大于同龄男性对照儿童、相邻RR间期差值的均方根（RMSSD）小于后者;≥12岁男性患儿DC小于、AC大于同龄男性对照儿童;≥12岁女性患儿DC小于同龄女性对照儿童,差异均有统计学意义（P〈0.05）。结论不明原因心前区不适患儿的迷走神经张力降低,DC明显低于正常组,且与HRV多项指标有密切相关性。患儿组DC、HRV性别差异不明显。≥12岁患儿组DC明显低于同龄对照组,提示青春期儿童易发生自主神经功能紊乱。     

健康婴儿心率减速力和心率变异性的变化及其相关性

目的观察健康婴儿的心率减速力(DC)、心率加速力(AC)和心率变异性(HRV)的变化及其相关性。方法 82例健康婴儿接受24h动态心电图检查,按月龄不同分为小婴儿组(6个月)和大婴儿组(6~12个月)。计算机自动测定其24 h的DC、AC及HRV时域指标(SDNN、SDANN、RMSSD、PNN50)与频域指标(LF、HF);比较两组婴儿的DC、AC及HRV各项指标,并分析DC、AC与HRV各项指标之间的相关性。结果大婴儿组的DC为(3.96±1.53)ms明显高于小婴儿组的(3.20±1.44)ms,而AC为(-3.84±1.10)ms明显低于小婴儿组的(-3.11±0.95)ms,差异有统计学意义(P均0.05)。24 hDC与心率呈显著负相关(r=-0.56,P=0.000),与SDNN、SDANN、RMSSD、PNN50、LF和HF之间呈显著正相关(r=0.25~0.75,P均0.05);24h的AC值与心率呈显著正相关(r=0.78,P=0.000),与SDNN、SDANN、RMSSD、PNN50、LF和HF之间呈显著负相关(r=-0.88~-0.56,P均0.01)。结论婴儿期的DC与HRV多项指标随月龄增加而增大,AC随月龄增加而减小;DC、AC与心率及HRV各项指标密切相关。     

超重、肥胖儿童与代谢综合征患儿心率减速力的研究

目的探讨超重、肥胖儿童及代谢综合征(MS)患儿的心率减速力(DC)、心率加速力(AC)及心率变异性(HRV)差异;体质指数(BMI)与DC、AC、HRV各指标间的相关性。方法选择≥10岁的超重、肥胖儿童103例,其中诊断为MS患儿48例;测定DC、AC、HRV各指标。结果 MS组DC值为(5.97±1.77)ms,低于非MS组的(7.93±1.56)ms;AC值为(-6.78±1.56)ms,高于非MS组的(-8.17±1.61)ms;HF值为335.2 ms~2(157.03~659.33 ms~2),低于非MS组的497.5 ms~2(345.6~767.1 ms~2);BMI为(29.64±2.83)kg/m~2,高于非MS组的(26.79±1.83)kg/m~2,差异均有统计学意义(P0.05)。超重、肥胖儿童BMI与DC呈显著负相关(r=-0.241,P=0.014),与AC呈正相关(r=0.199,P=0.044)。结论 MS患儿的自主神经功能受损,表现为迷走神经张力降低。肥胖程度越高,迷走神经张力越低,机体对心脏的保护力就越差,越易引起心血管疾病的发生。     

学龄期肥胖儿童胰岛素抵抗与心率变异性及心率减速力的相关性

目的探讨学龄期肥胖儿童胰岛素抵抗(IR)与心率变异性(HRV)、心率减速力(DC)及心率加速力(AC)之间的关系。方法选取学龄期6～10岁肥胖儿童83例,根据空腹血糖及空腹胰岛素值计算胰岛素抵抗指数(IRI),再根据IRI值将实验对象分为IR组45例和非IR组38例。在检测空腹血糖及空腹胰岛素同日行24小时动态心电图检查,计算出DC、AC、HRV各指标。比较IR组与非IR组DC、AC、HRV各指标,并进行相关性分析。结果 IR组DC、正常RR间期标准差(SDNN)、5分钟均值标准差(SDANN)、高频功率(HF)均低于非IR组,AC高于非IR组,差异均有统计学意义(P0.05)。肥胖儿童的IRI与DC、SDNN、SDANN、相邻RR间期差值的均方根(RMSSD)、低频功率(LF)、HF均呈显著负相关(r=-0.475～-0.249,P0.05),与AC呈显著正相关(r=0.488,P0.01)。结论 IR较非IR肥胖儿童的自主神经功能损伤严重,主要表现为迷走神经张力降低,且IRI越高,迷走神经张力越低。     

甲状腺功能亢进症儿童的甲状腺激素与心率减速力及心率变异性的相关性

目的 对甲状腺功能亢进症（简称“甲亢”）儿童的心率减速力（DC）、心率加速力（AC）、心率变异性（HRV）进行分析,并探讨甲亢儿童的血清甲状腺激素水平与DC、AC及HRV的关系。方法 选取甲亢儿童47例,另选取50例健康儿童为对照组,对所有受试者行24 h动态心电图检查,将甲亢组与对照组的DC、AC、心率（HR）及HRV各指标[RR间期总体标准差（SDNN）、RR间期平均值的标准差（SDANN）、相邻RR间期差值的均方根（RMSSD）、低频功率（LF）、高频功率（HF）]进行比较,并将甲亢儿童的甲状腺激素指标[游离三碘甲状腺原氨酸（FT3）、游离甲状腺素（FT4）]与DC、AC及HRV各指标进行相关性分析。结果 甲亢组的DC、SDNN、SDANN、RMSSD、LF、HF均低于对照组;AC和HR均高于对照组（P < 0.05）。甲亢儿童的血清FT3、FT4与DC、SDNN、SDANN、RMSSD、LF、HF均呈负相关（P < 0.05）;与AC和HR呈正相关（P < 0.05）。结论 甲亢儿童的心脏自主神经功能受损,表现为迷走神经张力降低。血清甲状腺激素水平越高,迷走神经张力越低,提示发生心血管疾病的危险性越大。     

血管迷走性晕厥患儿无症状期自主神经功能分析

目的分析无症状期心率减速力(DC)对血管迷走性晕厥(VVS)的诊断价值。方法选取2018年1月至2019年12月确诊为VVS的45例患儿作为VVS组,同期在门诊体检的45例健康儿童作为对照组,完善24小时动态心电图检查,比较VVS患儿和健康儿童的基础DC值、连续心率减速力(DRs)及心率变异性(HRV)各指标的变化情况,并按年龄段及性别进行分组比较;同时分析DC与HRV各指标间的相关性及DC对VVS诊断的预测价值。结果 VVS组的DC值、DR8及低频功率与高频功率之比(LF/HF)均明显高于对照组,差异均有统计学意义(P0.05)。在VVS组中,学龄期患儿的DC值、DR4及低频功率(LF)均明显低于青春期患儿,差异均有统计学意义(P0.05),而男女患儿的DC值、DRs、HRV各指标差异均无统计学意义(P0.05)。对照组年龄段及性别组间DC值、DRs、HRV各指标差异均无统计学意义(P0.05)。学龄期VVS组的DC值明显高于对照组,青春期VVS组的DC值、DR4、DR8及LF均明显高于对照组,差异有统计学意义(P0.05)。DC与HRV多项指标呈显著正相关(r=0.31～0.67,P均0.05),与LF/HF呈显著负相关(r=-0.36,P0.05)。行二分类logistic回归分析发现,青春期患儿仅DC与VVS相关(P0.05)。采用受试者工作特征曲线(ROC)分析发现,学龄期DC值以7.72 ms、青春期DC值以8.36 ms为界值时有较好的灵敏度及特异度。结论 VVS患儿无症状期自主神经功能存在异常,随年龄增长,自主神经功能异常更加显著。学龄期及青春期VVS患儿均有迷走神经张力升高,且青春期VVS患儿还有一定程度交感神经张力升高;DC与迷走神经张力间呈明显正相关,对VVS诊断有较好预测价值。     

学龄期肥胖儿童心脏自主神经功能分析

目的对学龄期肥胖儿童的心率减速力(DC)、心率加速力(AC)及心率变异性(HRV)进行分析,并观察肥胖儿童体重指数(BMI)与DC、AC及HRV的相关性。方法选取学龄期肥胖儿童108例,其中血脂正常组75例,血脂异常组33例,另选取103例学龄期健康儿童为对照组。对所有受试者行24 h动态心电图检查,分别将肥胖组与对照组、肥胖儿童中血脂异常组与血脂正常组的DC、AC及HRV进行比较,并将肥胖儿童的BMI与DC、AC及HRV进行相关性分析。结果肥胖组的DC、RR间期总体标准差(SDNN)、RR间期平均值的标准差(SDANN)、相邻RR间期差值的均方根(RMSSD)、低频功率(LF)、高频功率(HF)均低于对照组,AC高于对照组(P0.05)。肥胖儿童中血脂异常组的DC、SDNN、SDANN、RMSSD、LF、HF均低于血脂正常组,AC、BMI高于血脂正常组(P0.01)。肥胖儿童BMI与DC、SDNN、SDANN、RMSSD、HF呈明显负相关(P0.05);与AC呈明显正相关(P0.05)。结论学龄期肥胖儿童的自主神经功能受损,表现为迷走神经张力减低,其中合并血脂异常者以上表现尤为突出。肥胖程度越高,迷走神经张力越低,发生心血管疾病的危险性可能越大。     

有症状早搏患儿心率变异性的临床研究

目的 调查有心前区不适儿童早搏发生率,明确早搏与心率变异性(heart rate variability,HRV)的关系.方法 426例3～12岁有心前区不适儿童行24 h HRV时域分析;房性早搏(房早)、室性早搏(室早)按照Lown分级法分级,进行HRV分析.结果 (1)426例儿童中201例(47.2%)无任何心律失常.225例(52.8%)有早搏,其中单纯室早102例(23.9%),单纯房早77例(18.1%),同时合并房早、室早46例(10.8%).(2)在房早儿童中SDANN、PNN50值随着Lown分级升高而变化,差异具有显著性(F=4.39,P＜0.05;F=3.55,P＜0.05).2级以上房早儿童SDANN、PNN50值较0、1级儿童显著升高(P＜0.05);(3)在室早儿童中SDANN、RMSSD、PNN50值随着Lown分级升高而变化,差异具有显著性(F=3.61.P＜0.05;F=3.25,P＜0.05;F=2.63,P＜0.05).(4)有早搏儿童SDNN值较无早搏儿童差异无显著性(F=1.84,P＞0.05),SDANN、RMSSD、PNN50值差异有显著性(F=4.28,P＜0.05;F=2.72,P＜0.05;F=3.27,P＜0.05).结论 有心前区不适的儿童早搏发生率高于正常儿童,室早较房早发生率高.此类儿童有无早搏时心脏自主神经总张力是一致的,早搏的发生与交感神经张力增强、迷走神经紧张性抑制作用减弱有关.合并早搏时HRV均显著降低,室早降低最明显.无器质性心脏病儿童出现早搏可能系心脏自主神经功能紊乱所致,应用HRV分析鉴别早搏的性质具有临床意义.     

直立倾斜试验不同时间点心率和心率差对儿童及青少年体位性心动过速综合征的诊断效率

目的 探讨直立倾斜试验（HUTT）不同时间点心率（HR）和心率差（HRD）对儿童及青少年体位性心动过速综合征（POTS）的诊断效率。方法 选择诊断为POTS的6~16岁儿童及青少年217例为POTS组,匹配同期健康的儿童及青少年73例为对照组。POTS组又分为≤12岁亚组（n=127）和 > 12岁亚组（n=90）。分析比较两组儿童及青少年基线时、HUTT 5 min、HUTT 10 min的HR（HR0、HR5、HR10）及HUTT 5 min、HUTT 10 min的HR与HR0的差值（HRD5、HRD10）,并分析HR5、HR10、HRD5、HRD10对POTS的诊断效率。结果 POTS组HR5、HR10、HRD5、HRD10较对照组明显增加（P < 0.05）。HUTT 5 min时HR或HRD对男性患儿诊断POTS符合率高于女性患儿（P < 0.05）,HUTT 10 min时HR或HRD对男性患儿诊断POTS符合率低于女性患儿（P < 0.05）。> 12岁亚组HR诊断POTS符合率更高（P < 0.05）,≤12岁亚组HRD诊断POTS符合率更高（P < 0.05）。HR5、HR10、HRD5和HRD10 4项联合预测诊断POTS的曲线下面积（0.974,95%CI：0.949~0.989）大于上述各单项指标预测的曲线下面积（P < 0.05）,且灵敏度（87.80%）和特异度（95.83%）最高。HRD诊断效能高于HR（P < 0.05）。结论 HUTT不同时间点的HR和HRD对预测诊断儿童及青少年POTS具有较高价值,诊断POTS符合率存在年龄和性别差异。     

学龄前儿童病毒性心肌炎心率变异性与心率减速力分析

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24 h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。     

Circadian rhythm of heart rate and heart rate variability

BACKGROUND—Measurements of heart rate variability (HRV) are increasingly used as markers of cardiac autonomic activity.AIM—To examine circadian variation in heart rate and HRV in children.SUBJECTS—A total of 57 healthy infants and children, aged 2 months to 15 years, underwent ambulatory 24 hour Holter recording. Monitoring was also performed on five teenagers with diabetes mellitus and subclinical vagal neuropathy in order to identify the origin of the circadian variation in HRV.METHODS—The following variables were determined hourly: mean RR interval, four time domain (SDNN, SDNNi, rMSSD, and pNN50) and four frequency domain indices (very low, low and high frequency indices, low to high frequency ratio). A chronobiological analysis was made by cosinor method for each variable.RESULTS—A significant circadian variation in heart rate and HRV was present from late infancy or early childhood, characterised by a rise during sleep, except for the low to high frequency ratio that increased during daytime. The appearance of these circadian rhythms was associated with sleep maturation. Time of peak variability did not depend on age. Circadian variation was normal in patients with diabetes mellitus.CONCLUSION—We have identified a circadian rhythm of heart rate and HRV in infants and children. Our data confirm a progressive maturation of the autonomic nervous system and support the hypothesis that the organisation of sleep, associated with sympathetic withdrawal, is responsible for these rhythms.     

Circadian rhythm of heart rate and heart rate variability.

BACKGROUND: Measurements of heart rate variability (HRV) are increasingly used as markers of cardiac autonomic activity. AIM: To examine circadian variation in heart rate and HRV in children. SUBJECTS: A total of 57 healthy infants and children, aged 2 months to 15 years, underwent ambulatory 24 hour Holter recording. Monitoring was also performed on five teenagers with diabetes mellitus and subclinical vagal neuropathy in order to identify the origin of the circadian variation in HRV. METHODS: The following variables were determined hourly: mean RR interval, four time domain (SDNN, SDNNi, rMSSD, and pNN50) and four frequency domain indices (very low, low and high frequency indices, low to high frequency ratio). A chronobiological analysis was made by cosinor method for each variable. RESULTS: A significant circadian variation in heart rate and HRV was present from late infancy or early childhood, characterised by a rise during sleep, except for the low to high frequency ratio that increased during daytime. The appearance of these circadian rhythms was associated with sleep maturation. Time of peak variability did not depend on age. Circadian variation was normal in patients with diabetes mellitus. CONCLUSION: We have identified a circadian rhythm of heart rate and HRV in infants and children. Our data confirm a progressive maturation of the autonomic nervous system and support the hypothesis that the organisation of sleep, associated with sympathetic withdrawal, is responsible for these rhythms.     

正常儿童动态心电图窦性心率及心率变异分析

目的探讨正常儿童心率及心率变异性(HRV)特点。方法对804例正常儿童进行24h全程动态心电图检查,分析心率及HRV。结果不同年龄儿童窦性心率范围不同,年龄越小心率越快;儿童不同性别间HRV中24h内全部正常心动周期的标准差(SDNN)、24h内每5minNN间期标准差的平均值(SDNNindex)、NN50占所有N-N间期个数的百分数(PNN50)、极低频率(VLF)、低频(LF)差异有显著性;儿童不同年龄组间24h内5min节段平均心动周期的标准差(SDANN)、VLF、LF、全程相邻NN间期之间的均方根值(rMSSD)差异有显著性;儿童组与成人正常参考值中SDNN、SDANN、rMSSD差异有显著性,rMSSD儿童组中明显高于成人组。结论HRV是一种反映自主神经活性及其平衡的能定量、可重复的非侵入性的检测方法,是自主神经系统与心血管系统相互制约的结果。不同年龄、不同性别间儿童HRV存在显著差异;儿童组与成人参考值存在显著差异,尤其rMSSD儿童明显高于成人,提示儿童的自主神经功能较成人活跃,而随着年龄增长自主神经功能减退,尤其是迷走神经的紧张抑制功能明显减退。     

Heart rate turbulence in children--age and heart rate relationships

Heart rate turbulence (HRT) is a chronotropic response of the sinus heart rhythm to ventricular premature beat (VPB). Children show decreasing heart rate together with the maturation of the autonomic nervous system. The aim of the research was to assess the relationship between HRT parameters, age, and heart rate and time domain heart rate variability (HRV) parameters in healthy children. Twenty-four-hour ECG Holter recording was performed on 398 healthy children. The mean RR interval preceding VPB, number of VPBs, and HRT parameters-turbulence onset (TO) and turbulence slope (TS)-were determined. We observed significant correlation among TS and mean RR and age. Children with prepubertal status have lower values of TS compared with those during puberty. According to given quartiles, upper for TO was > or =-0.8%, lower for TS was < or =4.56 ms/RR, 13 patients (3%) obtained abnormal both TO and TS. The correlations between HRT and HRV parameters were observed among the youngest children. Age and heart rate preceding VPB have no effect on HRT onset in children, whereas HRT slope is highly dependent on these variables. Our results support hypothesis that in older children HRT is dependent on autonomic tone and also determined by other intrinsic modulators.     

Does fetal heart rate predict subsequent heart rate in childhood?

An investigation to determine whether there is any relationship between extremes of fetal heart rate during labour and subsequent heart rate at the age of 10 was carried out using data from the 1970 cohort of British Births. In 11,000 nationally representative children it was found that low fetal heart rate (below 120 beats/min) was associated with a heart rate at age 10 which was significantly lower than in those children whose fetal heart rate had remained between 120 and 160 beats/min (P less than 0.01). This relationship could not be explained by fetal asphyxiation, maternal antenatal hypotension or the method of pain relief during labour. There was no equivalent relationship with high fetal heart rate during labour. This could imply that some fetuses with low heart rates are not exhibiting fetal distress but have an inherent tendency to relatively slow heart rates.     

Metabolic rate of sleeping infants

AIM: To measure the sleeping metabolic rate (SMR) of healthy infants in the first year of life. METHODS: The SMR was measured on 73 infants aged 1 to 12 months in a special nursery using indirect calorimetry. One hundred satisfactory observations were made. The room air and radiative temperatures, humidity, and amount of insulation were measured. Parents chose the clothing and bedding that they judged their infant needed. RESULTS: The mean (SD) SMR was 2.4 (0.4) watts (W)/kg or 45 (10) W/m2. The mean SMR of infants aged 1-2 months was 38 compared with 44 W/m2 in infants of 8-12 months; the difference was not significant. There were no obvious differences in SMR between boys and girls. But there were wide differences in SMR between apparently similar infants, range 1.4 to 3.5 W/kg. Most parents selected insulation between 1 and 3 togs, and this was weakly negatively correlated with air temperature. CONCLUSION: These wide variations in SMR mean that it is impossible to give specific guidelines on the amount of clothing and bedding a particular infant will need for thermal comfort in a given room temperature.