无创法测定正常儿童左室后负荷及其收缩功能的研究

无创法测定正常儿童左室后负荷及其收缩功能的研究河南医科大学第一附院超声科秦石成，汤五洲为了解正常儿童的左室后负荷及其收缩功能的情况，本文用超声心动图测定左室内径及室壁厚度，结合袖带血压计测量的收缩压，测定了８０名正常儿童的左室收缩末期室壁应力（ＥＳＳ...     

毛细支气管炎合并心力衰竭患儿血浆Apelin和血管紧张素Ⅱ的表达

目的:研究毛细支气管炎合并心力衰竭患儿血浆Apelin和血管紧张素Ⅱ(angiotensin Ⅱ,Ang Ⅱ)的表达水平及其关系.方法:用放射免疫法测定32例毛细支气管炎合并心力衰竭患儿和28例毛细支气管炎不合并心力衰竭患儿以及17例健康体检儿童血浆Apelin和Ang Ⅱ含量.结果:(1)毛细支气管炎合并心力衰竭患儿血浆Apelin和Ang Ⅱ水平较毛细支气管炎不合并心力衰竭患儿和正常对照儿童均显著增高;(2)毛细支气管炎不合并心力衰竭患儿血浆Apelin和Ang Ⅱ水平与正常对照儿童比较有明显差异,但差异不具有统计学意义;(3)毛细支气管炎合并心力衰竭患儿血浆Apelin和Ang Ⅱ随心力衰竭的治疗而下降,治疗前后比较差异有统计学意义;(4)毛细支气管炎合并心力衰竭患儿血浆Apelin和Ang Ⅱ在治疗前后含量均呈正相关.结论:Apelin和Ang Ⅱ参与了毛细支气管炎合并心力衰竭的病理过程;且二者表达呈正相关.     

心力衰竭患儿心脏纵轴运动的定量组织速度成像研究

目的 探讨定量组织速度成像技术(QTVI)评价心力衰竭(CHF)患儿左心室纵轴运动及其与左心功能的关系.方法 获取标准心尖四腔观及两腔观,应用QTVI技术描记40例正常小儿及30例心力衰竭患儿左心室4个壁12节段心肌的组织多普勒速度曲线,分别测量各节段心肌运动曲线上收缩期峰值速度(Vs)和心肌各节段收缩期位移值(Ds),计算每一壁内基底段与中间段Vs及Ds均值.同时测量左心功能指标LVEF.结果 (1)CHF组患儿左心室Vs和Ds较正常组明显减低(P＜0.05);(2)各壁同一壁内Vs及Ds测值从基底段到心尖段逐渐递减的规律不如正常组明显;(3)各室壁速度及位移测值与LVEF的相关性有统计学意义.结论 Vs及Ds是评价左室纵轴运动的敏感指标,与左心功能指标LVEF相关性良好.QTVI可以快速、无创、定量评价心衰患儿左心室纵轴运动.     

心力衰竭患儿左室非同步运动与二尖瓣环运动速度的定量组织速度成像研究

目的探讨心力衰竭患儿左室非同步运动与二尖瓣环运动速度之间的关系。方法健康小儿40例,心力衰竭患儿30例,获取标准心尖四腔和两腔观。①在多普勒组织速度成像（DTI）状态下,测量左室后间隔、侧壁、前壁、下壁收缩期和舒张早期频谱中的峰值速度（Vs、Ve）,计算四个壁Vs和Ve均值;②QTVI状态下,测量并计算左心室四个壁12节段同步性指标Ts、Te的最大差值Max－△Ts和Max－△Te。同时测量左心功能指标左室射血分数（LVEF）。结果心力衰竭组Max—△Ts和Max—△Te明显大于正常对照组,差异有统计学意义（P〈0．01）;Vs、Ve的均值明显低于正常对照组,P〈0．01;直线相关分析显示MeanVs与Max—△Ts、MeanVe与Max－△Te、Max—△Ts与LVEF相关性好。结论心力衰竭患儿左室内心肌存在非同步运动现象,与二尖瓣环运动速度相关性好,可导致心功能下降。     

三维超声心动图评价左心室型单心室心肌收缩位移的临床研究

目的探讨三维超声心动图(3DE)在评价功能性单心室患儿心室各节段心肌室壁运动中的应用价值。方法研究对象分两组,病例组为51例功能性单心室患儿,均为左心室型单心室,对照组为51例正常儿童,应用Q-lab软件分析并计算功能性单心室主心腔及正常儿童左心室各节段心肌的最大收缩位移值,以及室壁收缩位移占舒张期室壁到左心室重心距离的百分比,即圆心位移值。结果病例组基底段后侧壁、前侧壁,中间段后侧壁、前侧壁,心尖段后壁、侧壁、心尖部的心肌位移值明显小于对照组的相应节段的心肌位移值(P<0.05)。病例组余心肌节段心肌位移值与对照组相应节段心肌位移值无明显统计学差异(P>0.05)。病例组心肌各节段的圆心位移值与对照组心肌各节段的圆心位移值无显著性差异。结论三维超声心动图可利用心肌收缩位移评估功能性单心室患者室壁运动。     

应用定量组织速度成像技术和组织追踪法研究急性期川崎病患儿左心收缩功能

目的应用定量组织速度成像技术和组织追踪法研究急性期川崎病(Kd)患儿左心收缩功能,以寻求川崎病早期心脏损害的诊断指标。方法通过M-型超声获得左室射血分数(EF);应用定量组织速度成像技术和组织追踪分析软件测量31例急性期川崎病患儿与20例正常儿童前间隔、后壁、前壁、下壁、后间隔和侧壁的二尖瓣环处、基底部和中间部的收缩期峰值速度(Vs)、收缩期最大位移(D),并比较两组间各参数。结果患儿组左室射血分数与正常组相比无统计学差异;患儿组各室壁的二尖瓣环处和部分室壁的基底部、中间部的Vs低于正常组(P<0.05)。6个室壁的平均Vs在二尖瓣环水平、基底部和中间部两组间均有统计学差异(P<0.05)。患儿各室壁各节段的收缩期最大位移均低于正常儿童,在所有二尖瓣环水平和部分室壁基底部、中间部两组间有统计学差异(P<0.05)。结论川崎病急性期左室整体和部分室壁局部收缩功能受损;定量组织速度成像技术和组织追踪法能够定量急性期川崎病左室功能改变。     

慢性心力衰竭患儿血清肿瘤坏死因子测定及意义

用放射免疫液相竞争法测定４６例慢性心力衰竭患儿血清中的肿瘤坏死因子α,其中３１例治疗好转后再次测定,并以３０正常儿童为对照。结果：恶性瓦衰患儿血清ＴＮＦ－α水平较正常显著升高,治疗好转后明显下降,但仍高于正常儿童;心功能越差,血清ＴＮＦ－α水平增高越明显;不同病因所致心衰之间ＴＮＦ－α水平无统计学差异。     

A-SMA技术评价病毒性心肌炎儿童左室局部功能的研究

目的 应用心肌自动分区运动分析(A-SMA)技术对病毒性心肌炎儿童左室局部功能进行研究.方法 A-SMA技术检测70例病毒性心肌炎儿童左室收缩期面积变化率(FAC-S)及舒张期面积变化率(FAC-D),患儿按心肌酶CK-MB增高与否分为两组,与40例正常儿童心功能指标进行对照分析;并且观察室壁运动彩色的变化.结果 2组病毒性心肌炎儿童不同切面收缩期和舒张期左室壁各节段FAC-S,FAC-D高低不均,大部分节段较正常儿童减低,差异有统计学意义或有显著统计学意义(P<0.05或P<0.001);病毒性心肌炎儿童室壁运动彩色变化不一致,色带层次减少或变窄.结论 A-SMA技术可以定量检测病毒性心肌炎儿童左室局部功能.     

正常儿童左室心肌的应变率及其影响因素

目的探讨我国正常儿童左室心肌应变率在各节段、室壁之间的分布特点以及与年龄、性别的关系。方法100例正常儿童按年龄分为4组，应用应变率成像技术分别测定左室心肌室间隔、侧壁、下壁、前壁各节段的应变率参数并分析。结果1～9岁儿童左室心肌各室壁收缩期和舒张晚期应变率由基底段向心尖段逐渐递减，心尖与基底段差异有统计学意义（P〈0．001）；10～14岁儿童收缩期、舒张早期应变率在各室壁、节段差异无统计学意义（P〉0．05）。不同性别儿童应变率各参数的差异均无统计学意义。结论正常儿童左室心肌收缩期和舒张早期应变率在各室壁、节段的分布随年龄增长逐渐趋向一致，不同性别儿童左室心肌应变率各参数的差异无统计学意义。     

速度向量成像评价左室型单心室短轴收缩功能

目的 观察左室型单心室短轴运动情况,评价速度向量成像(velocity vector imaging,VVI)技术估测左室型单心室患儿心室短轴收缩功能的价值.方法 左室型单心室患儿14例(单心室组)及正常儿童14例(对照组)为研究对象,应用VVI技术对主心腔短轴乳头肌水平室壁周向和径向应变及应变率进行分析.结果 单心室组前间隔、前壁、侧壁、下壁、后间隔节段的周向应变较对照组相应节段明显减低(均P ＜0.05).单心室组前间隔、前壁、侧壁、后壁、后间隔节段的周向应变率较对照组相应节段明显减低(均P ＜0.05).对照组的室间隔应变及应变率显著高于其余节段,差异有统计学意义(P＜0.05).单心室组各节段的径向应变及应变率较对照组相应节段明显减低,两组间差异具有统计学意义(P ＜0.05).对照组乳头肌水平各节段径向收缩期峰值应变及应变率差异无统计学意义(P＞0.05).结论 左室型单心室患儿存在周向和径向收缩功能不全,VVI技术能定量评价左室型单心室短轴节段室壁的收缩功能.     

速度向量成像估测正常儿童心室长轴心肌节段功能的研究

目的 通过速度向量成像（VVI）探索正常儿童左右心室长轴各节段运动的变化规律。方法采集44名健康儿童心尖四腔切面,Syngo Workplace软件测定各节段的速度、应变、应变率和位移,分析VVI参数与年龄之间的关系。结果 ①正常儿童左右心室的速度、应变、应变率和位移从基底段到心尖段依次降低。右室游离壁的速度、位移、应变和应变率明显高于左室游离壁和室间隔的相应节段（P〈0．05）。②左室游离壁基底段和中间段的速度与年龄具有较好的相关性（r=0．436,P〈0．01;r=0．464,P〈0．01）;右室游离壁的各节段速度与年龄无相关性（P〉0．05）。③左右室的游离壁基底段的应变与年龄具有较好的相关性（r=0．478,P〈0．Ol;r：0．497,P〈0．01）;右室游离璧中间段的应变率与年龄有较好的相关性（r=0．520,P〈0．01）。结论应变和应变率受到年龄的影响,因此在估测局部心肌节段功能时应考虑到该影响。     

Use of Angiotensin II Stress Pulsed Tissue Doppler Imaging to Evaluate Regional Left Ventricular Contractility in Patients with Hypertrophic Cardiomyopathy

There is controversy concerning whether contract-ility in the nonhypertrophied region of the left ventricular (LV) wall is impaired or normal in patients with hypertrophic cardiomyopathy (HCM). Global LV systolic function decreases with increases in afterload in this disease. This study was performed to identify abnormalities in regional LV contractility along the long and short axes in the setting of HCM with the use of angiotensin II (AT-II) stress pulsed tissue Doppler imaging (PTDI). Angiotensin II was administered intravenously to patients with asymmetric septal hypertrophy (HCM group, n = 21) and age-matched normal volunteers (N group, n = 12). We then measured the percent LV fractional shortening (%FS) and end-systolic circumferential LV wall stress by M-mode echocardiography, LV ejection fraction (LVEF) by 2-dimensional echocardiography, and time-velocity integral (TVI) of LV outflow velocity by pulsed Doppler echocardiography. The peak first and second systolic LV wall motion velocities along the long (L-Sw(1) and L-Sw(2)) and short (S-Sw(1) and S-Sw(2)) axes were measured in the LV posterior wall and ventricular septum with the use of PTDI. The end-systolic circumferential LV wall stress at baseline was significantly lower in the HCM group. The L-Sw(1) and L-Sw(2) for the posterior wall were significantly lower in the HCM group, but the S-Sw(1) and S-Sw(2) for the posterior wall and ventricular septum were similar in the two groups. The %FS, LVEF, TVI, and systolic PTDI variables along both axes for the posterior wall decreased significantly, and end-systolic circumferential LV wall stress increased significantly at AT-II doses of 0.005 or 0.010 microg/kg per minute in the HCM group. No significant changes were found in either group in the systolic PTDI variables (except for L-Sw(1)) for the ventricular septum with AT-II infusion. Contractility along the long and short axes of the nonhypertrophied LV wall is easily impaired with increases in afterload in patients with HCM, resulting in a decrease in global LV systolic function. We found AT-II stress PTDI to be a safe and useful technique for evaluating the regional LV systolic function in this disease.     

Effects of dobutamine on coronary flow velocity response and their relations to age

The purpose of this study was to assess the effects of low-dose dobutamine on left ventricular (LV) functional and coronary flow reserves using transthracic echocardiography. The study group consisted of 30 children aged from 5 months to 16 years (mean 4.8 +/- 4.4 years). Echocardiographic studies were repeated before and during dobutamine infusion (5 microg/kg per minute). The peak diastolic velocity in the left descending coronary artery (LAD) was recorded by pulsed-Doppler under the guidance of color Doppler flow mapping. The coronary flow velocity (CFV) response was calculated as the ratio of LAD peak flow velocity at dobutamine infusion to basal LAD peak flow velocity. Left ventricular contractility was calculated by two-dimensionally directed M-mode echocardiography. The rate-corrected mean velocity of circumferential fiber shortening (mVcfc) and LV end-systolic wall stress (ESS) were used as indices of contractility. Adequate spectral Doppler recordings of the LAD peak flow velocity for the assessment of CFV response were obtained in 26 of 30 patients (87%). The LAD peak flow velocity at dobutamine infusion increased significantly compared with the basal values. The CFV response in the younger children was low and increased significantly with age. The CFV response did not show significant correlations with the changes in heart rate, systolic blood pressure, rate-pressure product, nor ESS during dobutamine infusion. However, a significant relationship between the CFV response and the percent change of mVcfc was observed. In the present study using high frequency transthoracic echocardiography, we demonstrated the age-related changes in CFV response and LV functional reserve by dobutamine infusion. Responses of LV contractility and coronary flow to dobutamine are less sensitive in youngerchildren and increased with increasing age.     

Depression of Heart Rate Variability in Patients with Increased Ventricular Wall Stress

Background: Heart failure is characterized by neurohumoral dysfunction that can be assessed by measurement of heart rate variability (HRV). Depression of HRV is related to several hemodynamic parameters. We hypothesized that an increased left ventricular (LV) wall stress is related to a depressed HRV in patients with LV dilatation or dysfunction.
Methods: Cardiac function and mass were measured in 31 patients with LV dilatation or dysfunction and 21 controls using cardiac magnetic resonance (CMR) imaging. LV wall stress was calculated using a CMR-based thick-walled sphere model. Standard deviation of normal-to-normal (NN) intervals (SDNN) and average NN intervals over 5 minutes (SDANN-i) were calculated.
Results: LV end-diastolic (ED) and end-systolic (ES) wall stress were significantly increased in patients with SDNN < 75 ms (P < 0.05). SDNN and SDANN-i were decreased (P = 0.001, P < 0.001) in patients with LVED wall stress >8 kPa and LVES wall stress >30 kPa (P < 0.05). To examine potential effects of LVEF, LVED and LVES volume, and wall stress on HRV, a multiple linear regression analysis was performed, which revealed LVED wall stress as the only independent parameter influencing SDNN (P = 0.039). LV ejection fraction, LV mass, and volumes were not significantly related to HRV.
Conclusions: LV wall stress was independently related with depression of HRV. Therefore, LV wall stress might be prognostically important and a therapeutic target in heart failure.     

Left ventricular remodeling, mechanics, and tissue characterization in congenital aortic stenosis.

BACKGROUND: As the response of the myocardium to pressure overload is age-dependent, this study was designed to examine left ventricular (LV) remodeling, mechanics, and tissue characterization in children with moderate congenital aortic stenosis. METHODS: We studied by echocardiography Doppler 22 patients (mean age 12.4 +/- 5.6 years) with peak and mean transvalvular gradient of 63 +/- 6 and 32 +/- 4 mm Hg, respectively. In addition, 30 age- and body surface area-matched participants with structurally normal hearts were used as a control group. Sex- and age-specific cut-off levels for LV mass/height(2.7) and relative wall thickness were defined to assess LV geometry. As a load-independent index of myocardial contractility, the relation between the rate-corrected velocity of circumferential fiber shortening both at endocardium and midwall, and meridional end-systolic stress was assessed. In addition, LV diastolic function was also evaluated by the mitral flow indexes. Finally, ultrasonic tissue characterization of the LV myocardium was performed by calculating the magnitude of cyclic variation, which reflects the intramural contractile function, and the averaged myocardial intensity of integrated backscatter, which is directly related to the myocardium collagen content. RESULTS: The endocardial velocity of circumferential fiber shortening endocardium and meridional end-systolic stress relationship was within the normal range (mean +/- 2SD) in 18 of 22 patients (81.8%), and midwall velocity of circumferential fiber shortening at endocardium and meridional end-systolic stress was normal in all 22 patients. No mitral flow index of LV diastolic function was significantly different between aortic stenosis group and normal participants. In our study population, 16 of 22 patients (72.7%) showed normal LV geometry, 3 (13.6%) had a pattern of concentric remodeling, and 3 (13.6%) concentric hypertrophy. LV hypertrophy was not marked (left ventricular mass index [LVMI] < 51 g/m(2.7)) in any patient. Finally, compared with control participants our study population showed, both at interventricular septum and posterior wall, comparable values of cyclic variation integrated backscatter, but significantly higher values of averaged myocardial integrated backscatter intensity (P <.01). CONCLUSIONS: In children with moderate congenital aortic stenosis, the total amount of myocardial collagen was increased despite normal LV myocardial contractility and diastolic function. Furthermore, LV remodeling was abnormal in only about a quarter of our patients and none had more than mild hypertrophy. Although the majority of these patients do not have markers now recognized to predict higher risk of cardiovascular events, the long-term significance of myocardial fibrosis and its response to treatment remain to be investigated.     

Effect of aging on diastolic left ventricular myocardial velocities measured by pulsed tissue Doppler imaging in healthy subjects.

We evaluated the effect of aging on diastolic left ventricular (LV) wall motion velocity in 80 healthy persons with the use of pulsed tissue Doppler imaging. The wall motion velocity patterns were recorded at the middle regions of the LV posterior wall and ventricular septum in the parasternal (along the short axis) and apical (along the long axis) LV long-axis views. In the posterior wall, the peak early diastolic wall motion velocities (Ews) along both axes correlated inversely with age (long axis: r = -0.61, P <. 0001; short axis: r = -0.55, P <.0001), and the peak atrial systolic wall motion velocities(Aws) along both axes correlated directly with age (long axis: r = 0.59, P <.0001; short axis: r = 0.65, P <.0001). In the ventricular septum, the Ew along the long axis correlated inversely with age (r = -0.51, P <.0001), and the Aws along both axes correlated directly with age (long axis: r = 0.57, P <.0001; short axis: r = 0.53, P <.0001). The Ews along both axes at the posterior wall correlated directly with the peak early diastolic transmitral flow velocity. The Aws along both axes at the ventricular septum and posterior wall correlated directly with the peak atrial systolic transmitral flow velocity. The times from the second heart sound to the peak of the early diastolic waves of the ventricular septum and posterior wall along both axes significantly increased with age. The times from the aortic component of the second heart sound to the peak of the early diastolic motion velocities along both axes were significantly longer at the ventricular septum than at the posterior wall. Pulsed tissue Doppler imaging may be useful for evaluating the effect of aging on diastolic LV function in healthy persons.     

Effects of Enalaprilat on Regional Wall Stress in Patients with Angina Pectoris

Left ventricle (LV) cineventriculograms silhouettes in the right anterior oblique projection with simultaneous pressure micromanometry were assessed before and 10 min after administration of 1.25 mg enalaprilat intravenously to 10 patients with angina pectoris undergoing diagnostic cardiac catheterization. Cineventriculograms were divided into 20 areas using a modified Leighton's method for segmentalization of the LV and computed by the Janz's method for regional wall stress. Enalaprilat reduced preload and afterload in all cases. There was significant reduction in regional wall stress in 15 of the 20 segments after enalaprilat administration compared with baseline analysis. Segments without significant reduction in wall stress wee apical. There was significant reduction in global wall stress after enalaprilat. Thus, enalaprilat, in addition to improve hemodynamics decreasing both preload and afterload, reduces LV wall stress both regional and global. Clinical implications of these findings are in agreement with the wall stress reduction for prevention of ventricular remodeling with this agent in postinfarction patients.     

The Left Ventricular Apex is the Optimal Site for Pediatric Pacing:

Pacing at the commonly used right ventricular (RV) apex results in impaired ventricular performance. Previous animal studies indicated that the left ventricular (LV) apex is a superior pacing site. The purpose of this study was to investigate in dogs whether this good performance is associated with a more synchronous electrical activation pattern of the LV and whether the LV apex is also a good pacing site in children. In 11 healthy dogs and 8 children undergoing cardiac surgery, dual chamber pacing was performed at the RV apex, LV apex and LV lateral free wall (LVFW). In dogs, a basket electrode was inserted into the LV to assess pattern and timing of LV endocardial activation. In the children, hemodynamic measurements were performed immediately after recovery from cardiopulmonary bypass. In dogs, LV apex pacing resulted in synchronous activation around the LV circumference whereas RV apex and LVFW pacing resulted in asynchrony of activation between the septum and LVFW. In both canine and children's hearts most hemodynamic variables remained at sinus rhythm level during LV apex pacing, but LVdPdtmax, stroke work (dogs), and pulse pressure (children) were reduced as compared with sinus rhythm during RV apex and LVFW pacing. LV apex pacing results in synchronous activation of the LV and is, in adult dogs and in children, associated with superior hemodynamic performance. (PACE 2004; 27 [Pt. II]:837–843)     

Are there sex differences in regional systolic function and wall stress in hypertrophic obstructive cardiomyopathy? A three-dimensional echocardiography study.

OBJECTIVES: Sex-related differences in left ventricular (LV) systolic function have been previously reported in patients with aortic stenosis and hypertensive heart disease. The goal of this study was to determine systolic function of the LV in male and female patients with hypertrophic obstructive cardiomyopathy and to relate it to wall thickness and wall stress, respectively. BACKGROUND: Wall thickening, a parameter of regional systolic function, is determined by wall thickness and wall stress. A comprehensive analysis of regional LV function was performed from multiplane transesophageal echocardiography with 3-dimensional reconstruction of the LV. METHODS: In 21 patients (11 men and 10 women) 4 parallel (2 basal and 2 apical) equidistant short-axis cross sections from base to apex were obtained from the reconstructed LV. In each short axis, 24 wall-thickness measurements were carried out in 15-degree intervals at end-diastole (ED) and end-systole. Thus, a total of 192 measurements were obtained in each patient. Wall thickening, a parameter of regional systolic function, was calculated as the difference of ED and end-systolic wall thickness, and fractional thickening as thickening divided by ED thickness. RESULTS: Fractional thickening and wall stress were inversely related to ED wall thickness in both men and women. Women showed better LV systolic function when compared with men (P <.001). However, when corrected for wall stress, which was lower in women, there was no sex difference in systolic function. CONCLUSIONS: There are regional differences in LV systolic function in men and women that depend on regional wall thickness and wall stress.