不同基因型地中海贫血患儿血清铁代谢指标的研究

目的：探讨血清铁(SI)、总铁结合力(TIBC)、转铁蛋白(Tf)的检测在地中海贫血（地贫）中的临床应用价值。方法：对选取的9例静止型α地贫,56例标准型α地贫,26例血红蛋白H病,40例β地贫杂合子（β+地贫）,56例β地贫双重杂合子(或纯合子) （β0地贫）,45例缺铁性贫血（IDA）患儿以及70例健康儿童（对照组）血清SI、TIBC、Tf进行检测。结果：β0地贫组SI水平明显高于其余各组（P0.05）;静止型α地贫、标准型α地贫组SI、TIBC水平与对照组相近（P>0.05）,但Tf水平明显低于对照组（P0.05）。结论：SI和TIBC用于监测地贫患儿的铁负荷优于Tf。对于SI异常增高和TIBC明显降低的的小细胞性贫血患儿,诊断为β0地贫的可能性大。［中国当代儿科杂志,2010,12（2）：85-88］     

不同基因型地中海贫血患儿铁代谢和红细胞系造血状况研究

目的：探讨不同基因型地中海贫血（地贫）患儿体内铁代谢和红细胞系造血状况。方法：对158例确诊地贫患儿进行血清铁蛋白（SF）、血清转铁蛋白受体（sTfR）、促红细胞生成素（EPO）检测,比较不同基因型地贫患儿之间的差异,并分析其与血红蛋白水平的相关性。结果：158例地贫患儿中,轻型α地贫52例（32.9％）,血红蛋白H病（HbH病）27例（17.1％）,轻型β地贫59例（37.4％）,重型β地贫13例（8.2％）,α复合β地贫7例（4.4％）。HbH病及重型β地贫患儿的SF水平较其他各组明显升高,差异有统计学意义（P＜0.01）;重型β地贫患儿sTfR水平较其他各组升高,差异有统计学意义（P<0.05）。重型β地贫患儿EPO水平较其他各组明显升高,差异有统计学意义（P＜0.01）;HbH病和重型β地贫患儿Hb水平和EPO水平呈负相关,分别为γ=-0.656（P＜0.01）和γ=-0.641（P＜0.05）。结论：不同基因型地贫患儿体内铁代谢和红细胞系造血状况不同,联合SF、sTfR和EPO检测可反映造血状况,指导临床治疗。［中国当代儿科杂志,2010,12（8）：602-604］     

重型β珠蛋白生成障碍性贫血患儿生长发育指标与血清铁蛋白、血红蛋白量的关系和意义

目的 了解重型β珠蛋白生成障碍性贫血(简称β地贫)患儿生长发育指标落后情况,以及血清铁蛋白(SF)定量、每次输血前Hb量对其生长发育指标的关系和意义.方法 对59例重型β地贫(地贫组)患儿和48例同龄健康儿童(健康对照组)检测生长参数:身高[计算身高标准差分值(SDS)]、体质量[计算体质量指数(BMI)],Hb量、SF定量,青春发育分期采用Tanner分期方法 分期.应用SPSS 11.0软件进行统计学分析.结果 与对照组比较, 重型β地贫患儿组身高SDS、Hb量、SF定量水平均显著降低(t=-7.084,-25.771,11.928 Pa<0.01),而BMI无显著性差异(t=-0.326 P>0.05).青春期发育程度中,在重型β地贫组(10～14岁)21例患儿中仅2例开始发育,且均为Tanner 2期,而对照组(10～14岁)24例中全部开始正常发育,重型β地贫患儿发育显著落后.患儿身高SDS与年龄呈显著负相关(r=-0.588 P<0.01),与每次输血前Hb呈正相关(r=0.219 P<0.05),与SF无相关性(r=0.033 P>0.05).结论 重型β地贫的生长和发育指标均落后于正常同龄儿,年龄越大,落后越明显.其生长发育异常与患儿体内铁超负荷有关.患儿平时保持Hb水平相对高值,正规采用去铁胺等祛铁治疗将有助于改善患儿最终身高和发育水平.     

β地中海贫血患儿生长落后与甲状腺功能关系的探讨

为分析甲状腺功能状态在β地贫生长落后患儿中的变化，以探讨甲状腺功能在患儿生长的价值。我们对27例β地贫患儿（重型21例，中间型6例）进行了身高（H）、体重（W）、血红蛋白（Hb）、血清铁蛋白（SF）、三碘甲腺原氨酸（Ts）和甲状腺素（L4）的测定。结果患儿的H、W、Hb均低于正常儿（P＜0．05）；SF高于正常儿（P＜0．05）；Ts、T4在5岁以下组（20例）为正常（P＞0．05），在5岁以上组（7例）低于正常（P＜0．05）。我们认为β地贫患儿的生长落后与长期贫血有关，“甲低”为亚临床型，甲状腺激素水平的低下不仅是生长落后的加重因素。铁的长期沉积比单次检测更有意义。     

地拉罗司治疗重型β-地中海贫血铁过载患儿临床疗效及安全性研究

目的：探讨铁螯合剂地拉罗司（deferasirox,DFX）治疗重型β-地中海贫血（β-thalassemia major,β-TM）铁过载患儿的疗效及安全性。方法随机选择24例规律输血的β-TM铁过载患儿,参加DFX不同服药剂量的临床研究,调查血清铁蛋白（SF）的变化及不良反应。并将持续服用DFX 5年患儿与同期使用去铁胺联合去铁酮治疗患儿（对照组）的心脏MRI T2*、肝脏MRI T2*值进行比较。结果DFX每日20～30 mg/kg的起始剂量对于铁过载患儿无明显效果,加量至每日30～40 mg/kg 后SF水平下降显著(U=58,P＜0.01);不良反应以血清肝脏转氨酶升高最为常见,其次为血清肌酐非进行性升高。持续DFX 治疗5年组SF水平明显低于对照组（1748±481 ng/mL vs 3462±1744 ng/mL,P<0.05）;肝脏MRI T2* 值明显高于对照组（8.5±2.9 ms vs 2.7±1.9 ms,P<0.01）。两组心脏MRI T2*均值比较差异无统计学意义。结论DFX能显著降低β-TM 患儿SF水平,并显示出剂量依赖性变化;其对心脏铁负荷的减少未显示出明显优势,而对肝脏铁负荷的减低疗效显著。DFX治疗的不良反应以肝酶升高、血清肌酐非进行性升高为主。     

β地中海贫血患儿生长落后与甲状腺功能关系的探讨

为分析甲状腺功能状态在β地贫生长落后患儿中的变化，以探讨甲状腺功能在患儿生长的价值。我们对２７例β地贫患儿（重型２１例，中间型６例）进行了身高（Ｈ）、体重（Ｗ）、血红蛋白（Ｈｂ）、血清铁蛋白（ＳＦ）、三碘甲腺原氨酸（Ｔｓ）和甲状腺素（Ｔ４）的测定。结果患儿的Ｈ、Ｗ、Ｈｂ均低于正常儿（Ｐ〈０．０５）；ＳＦ高于正常儿（Ｐ〈０．０５）；Ｔｓ、Ｔ４在５岁以下组（２０例）为正常（Ｐ〉０．０５），在５岁以上组     

左向右分流型先天性心脏病合并心力衰竭患儿血清IGF-1和IGFBP-3的变化及意义

目的：探讨左向右分流型先天性心脏病（先心病）合并心力衰竭（心衰）患儿血清胰岛素样生长因子-1（IGF-1）和胰岛素样生长因子结合蛋白-3(IGFBP-3)的变化及意义。方法：20例健康儿童（对照组）,20例无心脏基础疾病的心衰患儿（心衰组）,20例无心衰的左向右分流型先心病患儿（先心组）,30例伴心衰的左向右分流型先心病患儿（先心+心衰组）作为研究对象。对不同组别的血清IGF-1及IGFBP-3进行比较;并对先心+心衰组患儿按心功能Ⅱ、Ⅲ、Ⅳ级分为3个亚组,对其血清IGF-1、IGFBP-3及cTnI水平进行比较及相关性分析。结果：先心组血清IGF-1及IGFBP-3水平下降,与对照组比较差异有统计学意义(P<0.01)。先心+心衰组血清IGF-1水平明显下降,与对照组及先心组比较差异有统计学意义(分别P<0.01,P<0.05)。心衰组血清IGF-1及IGFBP-3水平明显增高,与其他各组比较差异有统计学意义(P<0.01)。先心+心衰组患儿按心功能分级比较的各亚组间随心功能下降血清IGF-1水平依次降低(P<0.01),且该组患儿血清IGF-1、IGFBP-3水平与血清cTnI水平呈负相关（分别r=-0.692、-0.530,P<0.05）。结论：血清IGF-1水平可作为左向右分流型先心病病情评估的客观指标及合并心衰的危险因素,这也为该类患儿使用外源性IGF-1治疗心衰提供了临床依据。     

葡萄糖-6磷酸脱氢酶活性对珠蛋白生成障碍性贫血的辅助诊断价值

目的探讨葡萄糖-6磷酸脱氢酶（G-6PD）活性对珠蛋白生成障碍性贫血（地贫）的辅助诊断价值及其适用范围。方法采用琼脂糖凝胶血红蛋白电泳和（或）地贫基因检测、血常规、血清铁蛋白、G-6PD活性测定筛选940例儿童样本,将其分为3组（A组820例为单纯地贫患儿,B组40例为单纯缺铁性贫血（IDA）患儿,C组80例为健康对照组）,并对其G-6PD值进行相关统计分析。结果血红蛋白H（HbH）病、重型β地贫、中间型β地贫、IDA、轻型β地贫、α复合β地贫、轻型α地贫的G-6PD活性水平分别为（35.23&#177;7.11）、（34.95&#177;10.72）、（26.64&#177;10.85）、（23.86&#177;7.68）、（19.89&#177;5.99）、（18.65&#177;6.67）、（16.75&#177;5.49）NBT单位,与健康对照组比较均有显著性差异（Pa〈0.05）。G-6PD值辅助诊断HbH病及重型β地贫最优的临界点为25.75 NBT单位,ROC曲线下面积（Az）为0.903,灵敏度和特异度分别为83.1%、85.1%。αα/-α^3.7和αα/-α^-4.2二种静止型α地贫G-6PD值分别为（14.61&#177;4.19）和（13.14&#177;3.99）NBT单位,17M杂合子和41-42M杂合子2种轻型β地贫G-6PD水平分别为（18.77&#177;6.81）和（22.94&#177;7.43）NBT单位,经统计学分析无显著性差异（P〉0.05）。结论G-6PD活性对地贫的辅助诊断有一定价值,但有其适用范围,适用于HbH病及重型β地贫,不适用于地贫基因类型的鉴别。     

手足口病合并病毒性脑炎患儿血清铁蛋白及神经元特异性烯醇化酶水平的变化及意义

目的：探讨手足口病（HFMD）合并病毒性脑炎患儿血清铁蛋白和神经元特异性烯醇化酶（NSE）水平的变化及意义。方法：采用酶联免疫吸附（ELISA）与电化学发光法对20 例HFMD合并病毒性脑炎（脑炎组）和20 例单纯HFMD患儿(单纯HFMD组)进行血清铁蛋白和NSE水平测定,并与20 例正常健康儿(对照组)进行比较。结果：脑炎组血清铁蛋白含量为 212±71 μg /L,明显高于单纯HFMD组（85±18 μg /L）及对照组（70±15 μg/L）（均P＜0.01）;脑炎组血清NSE含量（8.6±2.6 μg/L）亦明显高于单纯HFMD组（6.0±1.3 μg/L）及对照组（5.6±1.8 μg/L）,（均P＜0.01）。治疗后脑炎组血清铁蛋白及NSE分别下降至126±37 μg /L、6.8±1.9 μg/L,较治疗前差异有统计学意义（P<0.01）。结论：HFMD合并病毒性脑炎患儿血清铁蛋白和NSE含量显著升高,对血清铁蛋白和NSE含量的检测有利于HFMD合并病毒性脑炎的早期诊断。     

新生儿缺氧缺血性脑病血清白介素-1β和白介素-18测定及意义

目的 探讨新生儿缺氧缺血性脑病（HIE）血清白介素（IL）-1β和IL-18的变化以及二者与HIE临床分度之间的关系。方法采用酶联免疫吸附法（ELISA）检测了70例HIE患儿（按临床分度分轻、中、重三组）及22例正常对照组足月新生儿第三天血清IL-1β和IL-18的水平。结果（1）HIE组新生儿血清IL-1β和IL-18均明显高于对照组（P〈0．05）；（2）与正常对照组比较，中、重度HIE组血清IL-1β和IL-18水平明显增高（P〈0．01）；轻度HIE组血清IL-1β、IL-18水平则与正常对照组无显著性差异（P〉0．05）。HIE组间血清IL-1β及IL-18两两比较，中度与轻度组比较有显著性差异（P〈0．05）；重度组与其他两组比较均明显升高（P〈0．01）。结论急性期HIE患儿血清IL-1β和IL-18水平与HIE临床分度基本一致。因此，血清IL-1β和IL-18水平可作为辅助诊断HIE的指标，对协助HIE临床分度具有重要价值。     

小儿扩张型心肌病心率变异性分析

目的分析扩张型心肌病(DCM)儿童的心率变异性(HRV)。方法DCM儿童23例(研究组),匹配健康儿童23例为对照(对照组)。采用康泰TLC3000A12通道动态心电图(EKG)分析系统描记24hEKG,分析心率、HRV的时域指标和频域指标。应用SPSS11.0软件进行统计学处理。结果与对照组比较,研究组最低心率明显增高(P<0.05),最高心率稍增高(P>0.05);HRV时域指标SDNN、SDANN、pNN50明显降低(P<0.05),rMSSD稍降低(P>0.05);HRV频域指标TP、ULF明显降低(P<0.05),VLF、LF、HF、LF/HF稍增高(P>0.05)。结论DCM儿童自主神经功能明显受损。     

北京地区3~12岁920名儿童心率变异性分层随机抽样调查分析

摘要 目的 测定920名3～12岁儿童心率变异性（HRV）时域指标值范围；明确HRV与年龄、性别的相关性；研究无症状期前收缩和QT延长儿童HRV的变化。方法 920名3～12岁儿童分为学龄前期组（3～6岁，274名)、学龄期组（～10岁，365名)、青春前期组（～12岁，281名)，行24 h HRV时域分析；进行各年龄组、性别HRV的方差分析；室性期前收缩按照Lown分级法分成4组，QT延长以QTc>450 ms为界分成正常和延长2组，分别进行组间HRV的方差分析。结果 ①HRV各时域指标值随年龄增长而增高，各年龄组均数间差异有统计学意义（P<0.01）。②按性别分组比较HRV 5项时域指标值，男性高于女性，总体标准差（SDNN）、均值标准差（SDANN）和标准差均值（SDNNINX）3项指标均数差异有统计学意义（P<0.05），学龄期和青春前期组SDNN、SDANN均数的男、女间差异有统计学意义（P<0.01），差值均方的平方根（RMSSD）和差值>50 ms的百分比（PNN50）均数差异无统计学意义（P>0.05）。③无期前收缩组与无症状偶发期前收缩组、频发期前收缩组和病理性期前收缩组HRV时域指标值差异无统计学意义（P>0.05）。④QT间期正常组和延长组HRV时域指标值差异无统计学意义（P>0.05）。结论 ①儿童HRV存在年龄差异。HRV的时域指标值随年龄增长而增加，提示儿童心脏自主神经系统发育尚不成熟，交感神经和迷走神经随年龄的增长发育渐趋完善和平衡。②学龄前期至青春前期，HRV男性高于女性。提示心脏自主神经总张力男性高于女性，男性心交感神经张力较女性相对增高；而心迷走神经张力男、女间差异无统计学意义，男、女心脏迷走神经功能发育可能较一致。青春期前，男、女间HRV的差异最为显著。可能提示此年龄段男、女间心脏自主神经发育的不一致性。③无症状期前收缩及QT间期延长儿童的HRV与其他儿童HRV相比无明显变化。     

Heart rate variability in diabetic children: Sensitivity of the time- and frequency-domain methods

Summary Heart rate variability (HRV) is a noninvasive index of the neural activity of the heart. Although also influenced by the sympathetic activity of the heart, HRV is essentially determined by the vagal stimulation of the heart. Several HRV abnormalities have been described in adults with diabetes mellitus. However, there are few data on HRV in children with diabetes mellitus. In the present study, HRV was assessed in seven healthy children, 10 diabetic children with good glycemic control and 11 diabetic children with poor glycemic control. All had normal standard cardiac autonomic function tests, obtained from 24-h Holter tapes. HRV was measured by calculating six time-domain (mean R-R interval (RR), standard deviation of the R-R interval [SDRR], standard deviation of the mean of 288 R-R intervals [SDANN], the mean of the 288 standard deviations computed for each 5-min period [SD], percentage of differences of adjacent R-R intervals of >50 msec for the entire 24 h [pNN50], and the root mean square of successive differences [rMSSD]) and four frequency-domain (low frequency [LF], high frequency [HF], total heart rate power spectra, and LF/HF ratio) indexes. SD, pNN50, rMSSD, LF, HF and total heart rate power spectra were markedly and significantly reduced in diabetic children with poor metabolic control. The 24-h variation of low- and high-frequency components of heart rate power spectra of the latter children had a differet shape. Thus, diabetic children with poor metabolic control (elevated HbA₁c and B₂M levels) have a low HRV compared to those diabetic children with good control and healthy chidren. These results can be interpreted as evidence of cardiac autonomic neuropathy in diabetic children with asymptomatic diabetic autonomic neuropathy.     

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.     

正常新生儿心率变异性研究

目的 探讨正常新生儿心率变异性（HRV）的特点。方法 应用Compas XM Holter分析系统对35例正常足月新生儿进行HRV时域分析。结果 新生儿出生后1～7d与8～28d HRV指标无差异（P＞0.05）。24h正常RR间期标准差（SDNN）、心率变异性指数（HRVI）与24h平均心率（AHR）、最慢心率（MiHR）呈中度负相关（r值分别为-0.44,-0.43,-0.51,-0.56,P﹤.05）。结论 HRV是反映新生儿心脏自主神经功能较稳定的指标,结果可供新生儿HRV研究参考。     

心率变异性分析有助于对儿童不明原因心悸的诊断

目的：心率变异性作为评价患儿心率变异程度的量化指标,临床上应用越来越广泛。该研究的目的是探讨不明原因心悸患儿心率变异性(HRV)的特点,为心悸患儿的临床诊断提供参考。方法：对34例不明原因心悸患儿,27例正常儿童进行动态心电图检查,分析动态心电图的STT变化及心率的昼夜节律变化,心率变异性时域指标两两比较。结果：心悸患儿时域指标相邻正常RR间期均数的标准差(SDNN)、相邻正常RR间期差值的均方根(RMSSD)、相邻正常RR间期差值大于50ms的个数占总心博数的百分比(PNN50)降低,与对照组相比差异有显著性(P<0.05)。其中15例患儿STT改变的特点符合β受体功能亢进症的诊断标准。结论：不明原因心悸患儿的心率变异性时域指标SDNN,RMSSD,PNN50均有下降,结合STT改变的特点,心率变异性分析可为临床诊断β受体功能亢进症和心脏神经官能症提供参考。     

Serum Angiogenin Level in Sickle Cell Disease and Beta Thalassemia Patients

Introduction: Angiogenesis has been investigated in different kinds of anemia. However, its role as a marker of angiogenesis has not been investigated in thalassemia or sickle cell disease (SCD). Objectives: We aimed to investigate serum angiogenin level in children and adolescents with beta thalassemia or SCD and its relation to possible risk factors of angiogenesis. Materials and Methods: This study included; 32 β-thalassemia major (β-TM) patients aged 14.2 ± 3.8 years, 20 β-thalassemia intermedia (β-TI) patients aged 14.3 ± 4.8 years, 20 SCD patients aged 14.1 ± 2.4 years; 8 with (HbSS) and 12 with sickle thalassemia (HbS/β-thalassemia) and 35 age and sex-matched controls. Data collected regarding; age, sex, disease duration, blood transfusion frequency, transfusion index, chelation type and duration, CBC, Hb electrophoresis, serum ferritin and serum angiogenin level (by ELISA). Results: Angiogenin level was significantly higher in patients with SCD [250 (100–300) pg/mL] compared to β-TM [180 (140–230) pg/mL] and controls [89 (80–103) pg/mL] (P < .001) especially those with HbSS (P = .06). There was a significant negative correlation between serum angiogenin and age of patients, age of onset and duration of chelation in β-TM (P < .01, P < .001, P = .003) and β-TI (P = .009, P = .03, P < .001) and with serum ferritin in β-TI group (r = ?0.573, P = .008). In SCD, angiogenin level was negatively correlated with both frequency of blood transfusion (r = ?0.731, P < .001) and duration of hydroxyurea therapy (P = .017). Conclusions: High angiogenin level detected among patients with SCD may be negatively influenced by regular blood transfusion and hydroxyurea therapy, while; early onset of chelation therapy may decrease angiogenin level in β-TM.     

北京地区3至12岁1581例健康儿童心率变异性分析

目的 探讨健康儿童早搏、房室传导阻滞、心率变异性（heart rate variability,HRv）与年龄、性别的关系.方法 1581例健康儿童分为3～6岁、～10岁、～12岁3组,按年龄、性别及室性早搏发生与否分组进行心律失常发生率、HRV的5项时域值的比较.结果 （1） ECG和24h心电监测（Holter）示健康儿童的平均心率、最慢心率和最快心率随年龄增加而降低,PR、QTc间期相反,除PR间期外其余各项指标差异均有统计学意义（P＜0.01）.（2）健康儿童Holter和ECG心律失常阳性检出率差异有统计学意义（x2 =4.810,P＜0.05）.（3）不同年龄组室上性早搏、室性早搏、Ⅰ.房室传导阻滞的发生率差异有统计学意义（P＜0.05）,且随年龄增长有升高或下降趋势;与3～6岁组比较,～ 10岁和～12岁组室性早搏发生危险度明显增加（OR =1.31和2.04）.（4） HRV的5项时域指标值随年龄增长而增高,各年龄组比较差异有统计学意义（P＜0.01）.（5） HRV的5项时域指标值男性均高于女性（P＜0.01）.（6）按室性期前收缩分组,HRV的5项时域指标差异均无统计学意义（P＞0.05）.结论 （1）健康儿童的心率随年龄增长逐渐下降,QTc间期随年龄增加而延长.（2）健康儿童Holter检测心律失常中室上性早搏的发生率最高.（3）健康儿童中室上性早搏、室性早搏的发生随年龄增长而增多,青春前期更明显.Ⅰ°房室传导阻滞的发生随年龄的增长有下降趋势.上述类型心律失常的发生与性别无关.（4）健康儿童HRV存在年龄差异,提示儿童心脏自主神经系统发育尚不成熟.（5）青春期前,男女间HRV的差异最为显著,提示可能此年龄段男女间心脏自主神经发育的不一致性.（6）健康儿童室性早搏的发生大部分为良性早搏.     

Comparison of Tissue Doppler Imaging with MRI T2* and 24-Hour Rhythm Holter Heart Rate Variability for Diagnosing Early Cardiac Impairment in Thalassemia Major Patients

Objectives: Cardiology follow up is important in thalassemia major patients. The object of this study is to define parameters which can be used in the early detection of cardiac impairment. Material and Methods: Forty seven beta thalassemia major patients (mean age 16.3 ± 4.47 years; 22 boys, 25 girls) whose left ventricular systolic functions were normal and a healthy control group of fifty age and gender matched children were included in the study. M-mode echocardiographic measurements, systolic and diastolic functions with PW and tissue Doppler and heart rate variabilities (HRVs) were compared between the two groups. The patients were also grouped according to MRT2*, ferritin and left ventricular diastolic diameters (LVDds) to compare the echocardiographic and Holter parameters among them. Results: None of the children in the study group had symptomatic congestive heart failure. PW Doppler late diastolic forward flow in pulmonary artery was higher in the thalassemia group when compared with the control group (P = 0.01) indicating decreased compliance of the right ventricle. While the systolic and diastolic functions were normal, all the HRV parameters in the thalassemia group were significantly lower than the control group (P = 0.005). Conclusions: Significant decrease in HRV and increase in PW late diastolic forward flow in pulmonary artery in the absence of systolic or diastolic dysfunction, points out that these parameters can be useful in detection of early cardiac impairment.