组织多普勒成像技术在评价胎儿房室传导时间方面的应用

房室传导是保障胎儿心脏活动正常进行的生理基础。与其它检查方法相比,组织多普勒成像技术(TDI)能更准确地进行胎儿房室传导时间的评价。本文将从TDI的原理、方法及优势几方面进行综述。     

应用组织多普勒成像技术测量正常胎儿房室传导时间的初步研究

目的 应用组织多普勒成像测量正常胎儿的房室传导时间,建立正常胎儿的房室传导时间参考值范围,为早期发现房室传导异常提供依据.方法 100名中晚孕超声筛查结果正常的胎儿(15～40孕周),按检查时不同胎龄分为5组进行研究.获得TDI动态图像后脱机软件QLAB分析测定房室传导时间,各组间进行方差分析并将AVCT与心率及孕周进行线性相关及线性回归分析;纳入研究的胎儿出生后尽量进行心电图和超声心动图检查.结果 正常胎儿房室传导时间范围为(123.9±10)ms;胎儿房室传导时间与心率成负相关(Y＝190.261-0.467X, P＜0.01),与孕周无明显相关(Y=0.045X,P=0.66).结论 组织多普勒成像为测量胎儿房室传导时间的良好方法;胎儿房室传导时间与孕周无相关,而与心率呈负相关;正常值的建立将有助于临床早期发现和诊断胎儿房室传导异常.     

组织多普勒成像技术在评估胎儿房室传导时间中的应用

房室传导是保障胎儿心脏活动正常进行的生理基础。与其他检查方法相比较,组织多普勒成像技术能更准确地评价胎儿房室传导时间。本文就组织多普勒成像的原理、优势、方法及指标选择等方面进行探讨。     

超声心动图对胎儿房室瓣的显像方法及其临床应用研究进展

作为目前检查胎儿心脏结构的主要手段,超声心动图在筛查先天性心脏病(CHD)中起重要作用。房室瓣畸形是胎儿CHD中较为常见的一类,准确评价胎儿房室瓣的形态与功能对产前诊断胎儿房室瓣畸形具有重要意义。本文对近年来国内外评价胎儿房室瓣的方法、房室瓣畸形的超声心动图特点等进行综述。     

超声速度向量成像三维数据成像技术观察心律失常胎儿心脏传导状态

目的 应用超声速度向量成像(VVI)三维数据成像技术评价胎儿不同类型心律失常中的房室传导模式.方法 收集经超声心动图检查确诊的心律失常胎儿60胎及正常胎儿40胎,行VVI,应用Siemens Syngo Workplace工作站分析三维数据成像.结果 VVI三维数据成像可清晰显示胎儿不同类型心律失常的房室传导形式.下传心房早搏提前出现的心房收缩后有心室收缩,后伴不完全代偿间期,未下传心房早搏在心房提前收缩后发生传导阻滞,其后无心室收缩;与窦性心律兴奋点比较,心房早搏位置轴发生改变.室上性心动过速伴不规律房室传导阻滞时,房室激动的速度轴降低,时间轴和位置轴无变化.心房颤动和心房扑动伴房室传导紊乱时心室律绝对不齐,房室激动的速度轴明显降低.Ⅱ度房室传导阻滞时,房室呈2∶1下传,完全性房室传导阻滞房室间运动无关联;房室激动的速度轴、时间轴和位置轴均无变化.结论 应用VVI三维数据成像可立体观察胎儿心脏传导状态.     

胎儿期Ⅰ°房室传导阻滞的诊断性研究分析

目的：选择较理想的指标及临界值点用于筛查胎儿Ⅰ°房室传导阻滞。方法：对62例晚孕孕妇（均大于38周）,进行组织多普勒成像（TDI）检测,记录Aa-IV（心房收缩期起点至等容收缩期起点的时间间隔）及Aa-Sa（心房收缩期起点至心室收缩射血期起点的时间间隔）,作为胎儿房室传导时间的评价指标。出生后一周内行新生儿心电图检查,测量PR间期。应用直线回归分析,比较Aa-IV、Aa-Sa与PR测值的相关性。绘制受试者工作特征曲线（ROC曲线）,分析比较Aa-IV、Aa-Sa的诊断准确性。结果：Aa-IV与PR的相关性更好。ROC曲线显示Aa-IV具有中等诊断意义;Aa-Sa诊断价值较低。根据敏感度及特异度分析,认为Aa-IV≥93.7 ms可作为筛查胎儿Ⅰ°房室传导阻滞的最佳临界值。结论：Aa-IV更适用于胎儿Ⅰ°房室传导阻滞的诊断,筛查胎儿Ⅰ°房室传导阻滞的最佳临界值为Aa-IV≥93.7 ms。     

定量组织速度成像与频谱多普勒超声心动图对胎儿心脏传导时间间歇的对照研究

目的 探讨定量组织速度成像技术(QTVI)在胎儿心脏传导时间间歇研究中的应用价值.方法 对116例无持续性心律失常的胎儿,分别采用QTVI和脉冲多普勒超声心动图(PD)测量胎儿的房室传导时间(AV)和心室开始收缩到下一心动周期心房开始收缩的时间间期(VA),采用t检验比较2种方法 测量的一致性.胎儿心脏传导时间与孕周、胎心率进行直线相关分析.结果 QTVI测量AV为(120.45±7.00)ms(95%CI,115.67～124.67 ms),VA为(300.31±23.51)ms(95%CI,287.67～316.00 ms);PD测量AV为(122.70±7.39)ms(95%CI,118.33～127.67 ms),VA为(297.85±22.15)ms(95%CI,284.83～310.33 ms).胎儿心脏传导时间与孕周呈正相关,与胎心率呈负相关.不同心率胎儿之间AV比较差异无统计学意义(P＞0.05).不同心率胎儿之间VA比较差异有统计学意义(P＜0.05);不同孕周胎儿之间AV及VA比较差异均无统计学意义(P＞0.05).结论 QTVI可简便快速地测定胎儿心脏传导时间,这在分析胎儿心律失r常方面具有重要的应用价值.     

产前超声心动图诊断胎儿Ⅰ度房室传导阻滞

目的 探讨产前应用多普勒超声技术测量胎儿心脏机械性PR间期并诊断胎儿Ⅰ度房室传导阻滞的临床意义.方法 选取经胎儿超声心动图检测出的100胎心脏疾病胎儿(疾病组),应用彩色多普勒引导脉冲多普勒取样容积记录左心室流人道及流出道血流频谱,测量PR间期及VA间期,并与120名正常胎儿(正常对照组)比较.结果 疾病组胎儿中先天性心脏病83胎、心律失常13胎、双胎输血综合征4胎,其中多普勒超声测量PR间期延长(131～220 ms)75胎.疾病组的PR、VA间期与正常对照组比较,差异有统计学意义(P<0.001).结论 多普勒超声心动图技术可以更好地获得房室传导时间的定位取样,且简便易行,对测量胎儿心脏机械性PR间期并诊断胎儿Ⅰ度房室传导阻滞有重要的临床价值.     

组织多普勒与脉冲多普勒超声评价胎儿心脏传导时间的定量研究

目的 确立正常胎儿的心脏传导时间参考值,探讨不同孕龄及心率对该值的影响.方法 189例孕妇,分别采用组织多普勒成像(TDI)和脉冲多普勒技术(PD)测量胎儿的房室传导时间(AV)和心室开始收缩到下-心动周期心房开始收缩的时间间期(VA),采用配对t检验比较两种方法测量的一致性,胎儿心脏传导时间与孕周、胎心率进行直线相关分析.结果 TDI测量AV为(126.56±15.33)ms,95% CI(124.10～129.03)ms;VA为(285.22±24.53)ms,95% CI(281.27～289.16)ms;PD测量AV为(127.42±12.88)ms,95%CI(125.35～129.49)ms;VA为(287.42±25.19)ms,95%CI(283.37～291.47)ms.TDI、PD测量胎儿心脏传导时间差异无统计学意义.胎儿心脏传导时间与孕周呈正相关,与胎心率呈负相关.PD、TDI测量AV在不同心率胎儿的比较差异无统计学意义,VA在不同心率胎儿的比较差异有统计学意义;PD、TDI测量AV、VA在不同孕周胎儿的比较差异无统计学意义.17例阵发性心律失常胎儿表现为AV、VA值的改变.结论 TDI、PD均可简单快速地定量测定胎儿心脏传导时间,胎儿心脏传导时间参考值的测定对于胎儿心律失常的评估具有潜在的应用价值.     

三种多普勒超声检查方法在定量测定胎儿心脏房室传导时间的应用

目的 采用3种多普勒超声检查方法:上腔静脉/升主动脉脉冲多普勒同步记录法(SVC/AAO)、二尖瓣环组织多普勒法(TDI)及肺动/静脉脉冲多普勒同步记录法(PA/PV)分别创建中晚孕期胎儿心脏房室传导时间(AV)正常值参考范围,并分析AV值与孕周、胎儿心率及心脏面积的相关性.方法 选取2019年6月至12月在浙江大学医...     

多普勒超声检测胎儿心脏机械性PR间期的临床意义研究

目的应用多普勒超声技术测量胎儿心脏机械性PR间期并探讨其临床意义。方法选取经胎儿超声心动图检出的83例疾病组胎儿,分别为先天性心脏病及心律失常。正常对照组为100例中、晚孕胎儿。应用彩色多普勒引导脉冲多普勒取样容积记录左心室流入道及流出道血流频谱,测量从舒张期二尖瓣A峰起始至收缩期主动脉射血起始的心房到心室的传导时间(PR间期),并同时测量收缩期主动脉射血起始至二尖瓣A峰起始的时间(VA间期)。结果 83例疾病组胎儿中先天性心脏病69例,心律失常12例,双胎输血综合征1例(双胎儿)。其中54例多普勒超声测量PR间期延长(131～220ms),并检出自身免疫性抗体阳性和弱阳性5例。正常对照组100例的中、晚孕孕妇均无自身免疫系统疾病,并经超声排除胎儿先天性心脏病、心律失常及其他胎儿异常,多普勒超声测量PR间期值均≤130ms。两组PR间期、VA间期比较差异有统计学意义(P0.01)。结论本研究结果表明,除孕妇患自身免疫性疾病可引起胎儿传导系统受损外,胎儿患先天性心脏病、心律失常等疾病时,其窦房结、房室结传导功能的易损性明显高于正常胎儿。其影响因素与心脏解剖结构异常和传导系统发育不良的相关性有待进一步研究。     

二维联合动态三维超声时空关联成像技术诊断胎儿完全型心内膜垫缺损

目的探讨二维联合动态三维超声时空关联成像(STIC)技术诊断胎儿完全型心内膜垫缺损(CTECD)的价值。方法应用超声心动图检查28 388例孕18~40周的胎儿,二维及彩色多普勒超声以胎儿四腔心切面为常规扫查切面,多切面扫查观察胎儿心脏大小、形态、房室结构、房室瓣开闭、左右心室流出道及其血流动力学改变,发现心脏解剖结构异常后应用动态三维超声STIC技术实时、动态观测胎儿三维房室结构及其血流动力学改变。结果本组28 388例孕妇中,超声心动图明确存在先天性心脏病胎儿861例,其中诊断CTECD 68例。结论二维联合动态三维超声STIC技术可诊断胎儿CTECD,可在短时间内直观地显示胎儿CTECD的大小、形态及其血流动力学改变。     

Is immune-mediated complete fetal atrioventricular block reversible by transplacental dexamethasone therapy?

We report for the first time a fetal case with sustained regression from isolated complete to first-degree heart block on transplacental treatment with high-dose dexamethasone. Doppler echocardiography is an excellent diagnostic tool in the non-invasive assessment of fetal atrioventricular conduction and its anomalies.     

M型超声结合房室梯形图分析法诊断胎儿心律失常的临床应用价值

目的 探讨M型超声结合房室梯形图分析诊断胎儿心律失常的价值。方法 回顾性分析2016年1月至2020年10月期间重庆市妇幼保健院经胎儿超声心动图检查应用M 型超声取样线获取房室壁、房室瓣及半月瓣的活动曲线,结合房室梯形图法分析及诊断胎儿心律失常类型。结果 M型超声结合房室梯形图法共诊断165例胎儿心律失常,其中房性早搏76例(46.1%),室性早搏6例(3.6%),窦性心动过速43例(26.0%),室上性心动过速8例(4.8%),其中房性心动过速1例(0.6%),心房扑动1例(0.6%),窦性心律过缓22例(13.3%),房室传导阻滞9例(5.5%)。结论 M型超声结合房室梯形图诊断胎儿心律失常可行,此方法简单、直观,能明确胎儿心律失常类型。     

胎儿房室瓣畸形的三维表面成像

目的 应用三维表面成像观察胎儿房室瓣畸形的立体形态结构,分析其三维图像特征。方法 分别获取58胎中晚孕期房室瓣畸形及97胎中晚孕期正常胎儿的心脏容积数据;房室瓣畸形胎儿中,完全型或部分型房室间隔缺损26胎,单心室共同房室瓣15胎,三尖瓣下移畸形2胎,瓣膜闭锁15胎。应用表面成像模式进行成像分析,对比观察房室瓣畸形及正常胎儿房室瓣的三维图像特征。结果 ①表面成像显示房室瓣畸形胎儿瓣环与正常胎儿相比存在明显不同。②表面成像模式可显示房室瓣畸形的立体形态,如完全型房室间隔缺损时,其共同房室瓣有5个瓣叶:前、后桥瓣,左、右壁瓣以及右前上瓣,开放时呈花瓣状。结论 三维表面成像能够逼真显示胎儿房室瓣畸形时的立体形态和活动特征,弥补二维超声观察胎儿房室瓣视野不足的缺点。     

A new and simple Doppler method for measurement of fetal cardiac isovolumetric contraction time.

OBJECTIVES: The fetal cardiac isovolumetric contraction time is defined as the interval between mitral valve closure and aortic valve opening. The objective of this study was to develop a simple and reliable Doppler method for measuring fetal isovolumetric contraction time using a digital filtering and processing system. METHODS: Cardiac Doppler signals were recorded from 40 fetuses at 18-40 weeks' gestation using a continuous-wave ultrasound transducer. The raw signal was digitized, filtered and divided into five different frequency ranges: 250-375, 375-500, 500-750, 750-1000 and 1000-1500 Hz. To determine the most suitable filter setting for detecting mitral valve closure and aortic valve opening signals, we examined whether they were detected clearly in each filter range. RESULTS: Both mitral valve closure and aortic valve opening signals were detected clearly in the 500-1000 Hz range. The atrioventricular flow and outflow noises in the 250-500 and 1000-1500 Hz ranges helped us to identify the signals. It was found that dividing the raw signals into three ranges of 250-500, 500-1000 and 1000-1500 Hz was the most suitable digital-filter setting for measuring isovolumetric contraction time. CONCLUSIONS: We have developed a simple Doppler method for measuring fetal isovolumetric contraction time. The advent of digital processing has simplified the equipment and the simultaneous multidisplay of three different filtered signals enables easy and accurate measurement.     

Atrioventricular Block Occurring Late After Heart Transplantation: Presentation of Three Cases and Literature Review

Sinus node dysfunction is a well-known occurrence following orthotopic heart transplantation, but atrioventricular block is rarely described. We compare the incidence and clinical presentation of atrioventricular block and sin us node dysfunction among the first 200 consecutive patients receiving heart transplantation at the University of Utah. Two of 200 patients (1%) required pacemaker implantation for symptomatic atrioventricular block compared to 13 of 200 (6.5%) who required pacemaker for symptomatic sinus node dysfunction. Of the patients with atrioventricular block, one had intermittent Mobitz II second-degree atrioventricular block and one had high grade atrioventricular block without ventricular escape. The most striking difference between the patients with atrioventricular block and those with sinus node dysfunction was the interval between transplantation and pacemaker implantation; time to pacemaker implantation in the atrioventricular block patients was 955 and 810 days compared to a median time of 26 days for sinus node dysfunction patients (P = 0.037). The patients requiring permanent pacemaker implantation were similar to those not requiring pacemaker implantation with respect to age, sex, ischemic time, and donor age. None of the patients requiring permanent pacemaker implantation was on amiodarone therapy within 2 months of transplant.     

The short-term effect of nifedipine tocolysis on placental, fetal cerebral and atrioventricular Doppler waveforms.

OBJECTIVE: To evaluate the effect of nifedipine on placental and fetal middle cerebral and atrioventricular Doppler waveforms. METHODS: Doppler waveforms of uterine (UtA), umbilical (UA) and middle cerebral (MCA) arteries and both atrioventricular valves were measured from 21 pregnant women/fetuses prior to and during nifedipine therapy for preterm labor. Maternal and fetal heart rates (FHR), maternal systolic and diastolic blood pressure, the Doppler pulsatility index and systolic/diastolic ratio of the UtA, UA and MCA were measured. The total time velocity integrals (TVI) of tricuspid and mitral valves and their E-wave/A-wave (E/A) TVI ratios were measured. Wilcoxon signed pairs test was used to compare the differences in Doppler parameters before and at 3 h after nifedipine loading up to a maximum dose of 40 mg. RESULTS: Fetal arterial and UtA Doppler parameters were not different before and after nifedipine therapy. Blood flow across the atrioventricular valves and the TVI were equally unaffected by nifedipine. The TVI x FHR product was also unchanged following nifedipine therapy. CONCLUSIONS: In women with otherwise uncomplicated pregnancies, nifedipine loading and tocolysis are generally well tolerated by the mother. Placental and fetal cerebral arterial blood flow, fetal systolic and diastolic cardiac function and downstream distribution of fetal cardiac output are unaffected by nifedipine loading. These results apply to women with unchanged vital parameters. Further studies are necessary to show long-term effects of nifedipine therapy and may help to refine choice of tocolytic agents.