心肌代谢和灌注不匹配的定量评价 及心功能恢复的预测

目的　定量评价急性心肌梗死 (AMI)再灌注后心肌代谢和血流灌注不匹配区域与发病 1个月后左室功能恢复之间的关系。方法　接受再灌注治疗的AMI患者 18例 ,1周内实施2 0 1TlCl和12 3 I β 甲基碘苯十五烷酸 (12 3 I BMIPP)双核素心肌断层显像并制成BMIPP/Tl图像 ,分析BMIPP/Tl异常区域与 1个月后左室功能恢复之间的关系。结果　BMIPP/Tl在 0 .94～ 0 .85区域的像数与 1个月后左室射血分数和室壁运动计分的改善 (ΔLVEF和ΔWMS)之间呈显著正相关 ,但BMIPP/Tl<0 .85区域的像数和ΔLVEF和ΔWMS不相关。结论　应用BMIPP/Tl图像定量评价AMI再灌注后心肌代谢和灌注的不匹配程度 ,可以客观地评价疗效和预测慢性期心功能的恢复 ,有十分重要的临床意义。     

Myocardial imaging with 123I-BMIPP in patients with congestive heart failure

First, we studied the diagnostic utility of myocardial imaging with 123I-BMIPP (BMIPP), a 3-methyl-branched fatty acid analog, in patients with various types of cardiomyopathy and left ventricular dysfunction (ejection fraction below 40%) by comparing with myocardial flow tracer imaging. The incidence of a dissociation between myocardial BMIPP and 201Tl distributions (BMIPP< 201Tl) as a marker of metabolic abnormality in viable tissue varied considerably among various heart diseases. Patients with ischemic cardiomyopathy and the dilated form of hypertrophic cardiomyopathy had a higher incidence while those with idiopathic dilated, alcoholic and hypertensive cardiomyopathy had a lower incidence. These results suggest that the marked difference between ischemic and idiopathic dilated cardiomyopathies may contribute to the differential diagnosis between these two diseases which are main basic abnormalities in congestive heart failure. Second, we investigated the relationship between myocardial BMIPP uptake and ventricular stress in patients with right ventricular pressure overload due to pulmonary hypertension. Myocardial BMIPP uptake in the right ventricle estimated by referring to uptake in the left ventricle showed a significant correlation with mean pulmonary artery pressure (mPAP) and no significant difference with myocardial 99mTc-sestamibi uptake in the 15–81mmHg mPAP range. These results suggest that myocardial utilization of free fatty acid may be preserved in the presence of higher ventricular wall stress.     

巢蛋白在低氧大鼠肺组织及肺动脉平滑肌细胞的表达及意义

目的研究不同间期低氧大鼠肺组织及低氧培养的肺动脉平滑肌细胞（PASMC）中巢蛋白的表达变化。方法24只雄性sD大鼠随机分为正常对照组（N组）,低氧2周组（H2W组）,低氧4周组（H4w组）。测定大鼠肺动脉平均压（mPAP）、颈动脉平均压（mCAP）、右心室／（左心室＋室间隔）质量比[RV/（LV＋S）]、肺动脉相对中膜厚度（PAMT）;免疫组织化学染色测定肺动脉巢蛋白含量。分别采用逆转录PCR和蛋白印迹法检测各组大鼠肺组织巢蛋白的mRNA及蛋白含量。蛋白印迹法检测常氧和缺氧培养的PASMC中巢蛋白的蛋白含量。结果H2W组、H4w组mPAP、RV／（LV＋S）、PAMT、肺动脉巢蛋白的蛋白含量、肺组织匀浆巢蛋白mRNA及蛋白含量均显著高于N组（P〈0．01）,且随着低氧时间的延长,逐渐增加;肺动脉平滑肌细胞中的巢蛋白的蛋白含量,随着低氧培养的时间的增加而逐渐增高（P均〈0．05）。结论低氧时巢蛋白在大鼠肺组织及肺动脉平滑肌细胞中的表达增加,后者可能在肺血管重构中起着重要作用。     

Right ventricular pressure overload during acute lung injury: Cardiac mechanics and the pathophysiology of right ventricular systolic dysfunction

Right ventricular (RV) pressure overload (PO) accompanying acute lung injury is associated with a poor prognosis. To determine if RV ischemia (RVI) is responsible for RV failure (RVF) during acute PO induced by an acute lung injury, a group of eight dogs was studied with the pericardia open after instrumentation with RV, left ventricular (LV), and pulmonary artery (PA) Millar catheters, a PA thermodilution catheter, an aortic fluid-filled catheter, and RV and LV septal-free wall segment length crystals. The animals were studied during baseline, and after infusing glass beads into the right atrium sufficient to first double the PA pressure (PAP), then triple the PAP, and finally to produce RVF (decreased cardiac output with increased RV preload). Transmural RV biopsies were obtained at each phase for adenosine triphosphate and creatine phosphate (CP) assays. To determine the mechanism of RVI, a second group of nine dogs was studied (with the pericardia closed) at baseline, after a doubling of PAP and during RVF. Right ventricular myocardial blood flow was determined by a microsphere technique at each phase and was correlated with the determinants of RV myocardial O₂ demand and supply. In the open pericardia group, RVF, but not doubling or tripling of PAP, was associated with a decrease in CP to 50% of baseline conditions, confirming RVI (4.82 ± 3.67 versus 10.39 ± 3.94 μmol/gm wet weight; P < .005). In the closed pericardia group, RV myocardial blood flow increased in response to myocardial O₂ demands (multiple R = .69 for endocardial and .64 for epicardial flow; P < .05), although the ratio for total RV blood flow to myocardial O₂ demand ratio (planimetered area beneath RV pressure tracing) decreased (4.88 ± 2.76 versus 2.08 ± 2.14; P < .05). In both groups of dogs, RVF was associated with a similar decrease in LV end diastolic segment length or preload (17% in open group and 10% in closed group; P = NS between groups) and stroke work. From these observations, we conclude that after an acute lung injury, RVPO induces RVF because RV myocardial O₂ demand outstrips RV myocardial O₂ supply. Coincidentally with RVF, LV function is depressed on a preload-mediated basis independent of the pericardium, suggesting a dominant “series” interaction between both ventricles. These observations suggest that therapy in patients with acute lung injury is better aimed at increasing RV myocardial blood flow and RV function.     

辛伐它汀干预后肥大细胞在肺动脉高压中的变化

目的:建立SD大鼠高肺血流,注射野百合碱所致肺动脉高压模型,并用辛伐它汀干预,观察肺组织中肥大细胞及肥大细胞两种亚型的变化,探讨辛伐它汀干预后肥大细胞在肺动脉高压中的改变及其机制。方法:采用腹主动脉-下腔静脉造瘘,术后第二天治疗组给予辛伐它汀2mg/kg干预,并于术后7天给予治疗组和模型组一次性腹腔注射野百合碱60mg/kg,制造肺动脉高压(pulmonary hypertension)动物模型,正常SD大鼠作为对照组,35天后测定肺动脉压力。取右下肺组织,用抗类胰蛋白酶单克隆抗体和抗类糜蛋白酶单克隆抗体免疫组织化学染色观察实验组与正常组之间肥大细胞数量的变化,HE染色观察肺组织一般病理变化。结果:HE染色显示模型组肺组织中动脉管壁明显曾粗,有新生血管形成。平均肺动脉压力(mPAP)模型组动物较对照组明显升高(P<0.05),模型组较治疗组也明显升高(P<0.05);右心室/(左心室 室间隔)(RV/LV S)模型组较对照组明显增加(P<0.05),模型组较治疗组也明显增加(P<0.05),肥大细胞总数(类胰蛋白酶阳性的肥大细胞)及类糜蛋白酶阳性的肥大细胞模型组较对照组明显增多(P<0.05),肥大细胞在治疗组较模型组明显减少(P<0.05)。结论:腹主动脉-下腔静脉造瘘合并野百合碱腹腔注射成功地建立了肺动脉高压的动物模型,已有文献报道肥大细胞可能参与了肺动脉高压的形成,免疫组织化学染色显示在辛伐它汀干预后肥大细胞的总数治疗组较模型组明显减少,对临床治疗肺动脉高压提供了新的思路。     

Sonographic sign suggesting the prenatal diagnosis of coarctation of the aorta

Coarctation of the aorta is a serious heart defect that can be successfully treated if identified early. Actual narrowing of the aortic isthmus is very difficult if not impossible to demonstrate on prenatal sonography; however, the indirect sign of discrepant ventricular sizes (right ventricle [RV] greater than left ventricle [LV]) is potentially useful to identify fetuses at risk for having coarctation of the aorta. We report on nine fetuses, 18 to 38 weeks gestation, in which the left ventricle was smaller than the right ventricle. After birth, four of the nine had coarctation of the aorta. One infant with Down's syndrome had a patent ductus arteriosus as well as foramen ovale. Another infant had a small left ventricle and parachute mitral valve but no coarctation. The last three infants had a normal cardiac workup at birth. We conclude that a small left ventricle compared to the right ventricle on prenatal sonography can be a sign of congenital heart disease and that one of the defects that can give this appearance is aortic coarctation. Careful neonatal follow-up is warranted.     

右心室不同部位起搏时左心室总体及节段心肌收缩功能的超声评估

目的 应用斑点追踪显像技术评价右心室不同部位起搏对左心室总体及节段心肌收缩功能的影响.方法 获取右室间隔起搏组(9例)、右室心尖起搏组(15例)、正常对照组(13例)心尖左室长轴观、胸骨旁左室短轴观图像,测量各节段峰值纵向应变(S_L)、峰值径向应变(S_R),计算左室总体峰值纵向应变(GS_L)、总体峰值径向应变(GS_R).结果 右室心尖起搏组GS_L[-(18.29±2.67)%]低于正常对照组[-(21.07±2.08)%]及右室间隔起搏组[-(20.54±2.29)%],差异均具有统计学意义(P＜0.05),右室间隔起搏组与正常对照组GS_L比较差异无统计学意义(P＞0.05).而右室心尖起搏组GS_R[-(26.85±7.73)%]与右室间隔起搏组GS_R[(28.59±6.06)%]均低于正常对照组[(36.26±9.37)%],差异有统计学意义(P＜0.05),两起搏组间GS_R差异无统计学意义(P＞0.05),但右室心尖起搏组GS_R有进一步降低趋势.两起搏组邻近起搏位点的左室节段心肌S_L及S_R较正常对照组相应节段明显降低,但右室间隔起搏组保持了与正常对照组相似的左室内应变分布,右室心尖起搏组左室内应变分布异常.结论 斑点追踪显像技术可定量评价右室不同部位起搏时左室总体及节段心肌收缩功能变化.     

Characteristics of hemodynamic and external respiratory function in patients with concomitant wounds of the heart and lung during early postoperative period

The parameters of intracardiac hemodynamics and external respiratory function (ERF) were studied by echocardiography and computed spirography with pneumotachometry in 123 patients with punctured and lacerated wounds of the chest in the early postoperative period. All the patients were divided into 6 groups according to the pattern of injuries. Group 1 included 25 patients with chest wound without organ damages; Group 2 comprised 42 patients with wound of the lung; Group 3 consisted of 22 patients with wound of the left ventricle (LV); in Group 4 there were 11 persons with wound of LV and the lung; Group 5 included 8 victims with wound of the right ventricle (RV); and Group 6 comprised 15 patients with wounds of the lung and RV. One- and five-day follow-ups revealed the most pronounced disorders of intracardiac hemodynamics and ERF in patients with concomitant wound of the lung and RV (Group 6). At the same time it was found that when wounds of the lung were concomitant with those of the heart, there was discoordination of RV and LV work with decreased volumetric blood flow along the pulmonary artery. These impairments also persisted by day 5 of the moment of wound. By that time there were positive hemodynamic and ERF changes in the other groups.     

Spatial Inhomogeneity of Cardiac Norepinephrine Transport Protein and Meta-[123I]Iodobenzylguanidine Uptake in Swine Myocardial Tissue

Purpose

The aim of the present study was to evaluate the expression of the cardiac norepinephrine transporter (NET) in the left ventricle (LV) of healthy pigs and its relationship with regional meta-[¹²³I]iodobenzylguanidine ([¹²³I]MIBG) myocardial uptake.

Procedures

Experiments were performed on animals injected with [¹²³I]MIBG and acquired 2 h later using an ultrafast CZT gamma camera to assess the regional myocardial uptake. After image acquisition, animals were euthanized; the heart was quickly excised and underwent to an ex vivo single photon emission tomography (SPECT) imaging. Four small samples of tissue were then harvested from mid-walls and apex of the left ventricle; NET densities were evaluated and further normalized for protein loading per cardiac region.

Results

Three variants of NET protein with different molecular weights were detected. The expression of NET was not homogenous in the LV, with the highest density in the inferior wall and the lowest one in the apical area. The regional in vivo [¹²³I]MIBG uptake revealed an analogous trend, showing a good linear relationship with NET expression. Parallel results were obtained from the ex vivo study.

Conclusion

This study elucidates the expression of three different variants of NET proteins into the left ventricular myocardium of a healthy pig. NET expression into the LV was not homogeneous and paralleled by differences in regional [¹²³I]MIBG uptake. Moreover, the correlation and the agreement between measurements of regional expression of NET variants and [¹²³I]MIBG uptake represent a relevant finding for inferences about NET expression in the context of clinical imaging.

     

Functional tricuspid regurgitation and the right ventricle: what we do not know is more than we know

The tricuspid valve (TV) lies in between the right atrium and the right ventricle (RV), consisting of annulus, leaflets, chords and papillary muscles. The RV appears triangular-shaped in a lateral view and crescent-shaped in a cross-section one. In normal conditions, the septum is concave toward the left ventricle (LV) in both systole and diastole and the RV volume is larger than the LV volume, although its mass is a third of the LV. The strict relationship between the TV apparatus and the RV underlies the physiological mechanism of TV functioning, and so, the RV plays an important role in case of functional tricuspid regurgitation. Nevertheless, the systematic assessment of RV is still not performed mainly due to lack of standardization. Hence, new echocardiographic guidelines have recently been proposed to standardize the RV assessment using transthoracic 2D?echocardiography. 3D-echocardiography and MRI are more useful to measure volumes and ejection fraction; in particular, MRI is able to provide a tissue evaluation. Today, surgical strategies are directed mainly to the annulus with fluctuating results because functional tricuspid regurgitation is not due only to the annulus but also to the RV, which is difficult to assess, due to its evolution being unpredictable and complicated by the interaction with LV.     

Fourier Analysis in Patients with Different Pacing Modes

The purpose of this study was to evaluate the usefulness of phase analysis in detecting the altered activation sequence induced by different pacing modes. Radionuclide ventriculography and planar gated blood pool scintigraphy were performed at rest in 56 patients with different pacemakers. This method permitted us to localize the pacemaker impulse site in the right ventricle and its diffusion in the heart. In patients with VVI pacemaker, this technique showed an evident asynchronism of contraction and relaxation of each ventricle and the standard deviation of phase angle (sigma), calculated by computer, is greater during pacing than sinus rhythm for left (LV) and right (RV) ventricles (LV sigma: 17 degrees +/- 4 vs 11 degrees +/- 3, less than 0.001; RV sigma: 31 degrees +/- 7 vs 14 degrees +/- 4, P less than 0.001). In the patients with VVI rate responsive pacemakers, the LV sigma changed from 18.5 +/- 3 under pacing to 11 degrees +/- 3 in sinus rhythm, P less than 0.001, while the RV sigma changed from 30 degrees +/- 8 to 14 degrees +/- 4, P less than 0.001. Instead in the patients with DDD pacemakers, the LV sigma changed from 15.5 degrees +/- 2 under pacing to 11 degrees +/- 3 in sinus rhythm, P less than 0.05, while the RV sigma changed from 29.1 degrees +/- 6 to 14 degrees +/- 4, P less than 0.001.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of right atrial function by two-dimensional speckle-tracking echocardiography in patients with right ventricular myocardial infarction

Right ventricular myocardial infarction (RVMI) damages the systolic and diastolic functions of the RV, so the right atrium interacts with the RV with an acutely altered function. The aim of our study was to compare right atrial function as evaluated by 2D speckle-tracking echocardiography (2DSTE) between patients with inferior wall myocardial infarction (INFMI) and patients affected by both inferior myocardial infarction and right ventricular myocardial infarction (INFMI?+?RVMI). Our study recruited 70 consecutive patients with INFMI (43 patients without RVMI and 27 patients with RVMI). Right atrial function was evaluated by 2DSTE. Early diastolic strain, systolic strain rate, absolute value of early diastolic strain rate, expansion index, and diastolic emptying index of the right atrium were reduced in the patients with INFMI?+?RVMI compared to the patients with INFMI. The area under the curve for early diastolic strain for INFMI diagnosis was 0.682 (p value?=?0.011, 95?% CI 0.550–0.815). Right atrial early diastolic longitudinal strain <27.5?% had 59.3?% sensitivity and 79.1?% specificity for the discrimination of INFMI?+?RVMI from INFMI. Our results demonstrated that right atrial reservoir and conduit functions were impaired in the patients with INFMI?+?RVMI compared with the patients with INFMI.     

CRT in a congenital heart disease patient with interventricular dyssynchrony due to an RV conduction delay

We encountered a unique pattern of cardiac dyssynchrony in a patient with complex congenital heart disease (heterotaxy syndrome) with a biventricular physiology and systemic left ventricle (LV). On speckle tracking echocardiography, dyssynchrony was not detected within the LV, but was noted in an interventricular fashion between the LV and right ventricle (RV). An electrophysiologic study revealed a conduction delay in the subpulmonary RV. Cardiac resynchronization therapy provided reverse cardiac remodeling and an excellent result in our patient by placing the pacing leads around the dyssynchronous lesion.     

超声组织多普勒成像评价儿童先天性心脏病并肺动脉高压患者心室功能研究

目的 探讨超声组织多普勒成像技术评价儿童先天性心脏病并肺动脉高压患者心室功能的价值.方法 20例先天性心脏病并肺动脉高压、20例先天性心脏病无肺动脉高压患儿及24例门诊体检健康儿童,分别行组织多普勒超声心动图检查.心尖四腔心切面测量左心室侧壁二尖瓣环附着处、右心室侧壁三尖瓣环附着处收缩期S波峰速度(Sm)、舒张早期负向E波峰速度(Em)、舒张晚期负向A波峰速度(Am)、等容收缩间期(ICT)、等容舒张间期(IRT)、射血时间(ET),计算左心室、右心室Tei指数,比较各组间差异,并分析先天性心脏病并肺动脉高压组患儿右心室组织多普勒参数与肺动脉收缩压(sPAP)的相关性.结果 先天性心脏病并肺动脉高压组患儿左心室、右心室Em及左心室ET降低,而左心室、右心室Am、ICT、IRT、Tei指数均异常升高.右心室IRT与sPAP具有良好的正相关.结论 儿童先天性心脏病并肺动脉高压患者左右心室功能均受损,以右心室舒张功能及左心室舒张收缩功能下降为主,右心室IRT可作为预测肺动脉高压的新无创指标.     

Changes of fibronectin in the right and left ventricles of rats exposed to chronic normobaric hypoxia.

Changes of fibronectin (FN) in the right and left ventricles of adult rats exposed to chronic normobaric hypoxia were observed by a peroxidase immunohistochemical stain technique and analyzed quantitatively by a point counting method. Fifty-six rats were randomly divided into control groups of day 0 (immediately prior to the experiment), day 5, day 15, and day 30 and hypoxia groups of day 5, day 15, and day 30. Rats of the hypoxia groups were put into a normobaric hypoxia chamber with oxygen concentration adjusted to 10 percent. The rats of the control groups breathed room air. From day 5 on, the ratio of the weight of the right ventricle (RV) to that of the left ventricle (LV) plus interventricular septum (SP), RV/(LV+SP), and the ratio of the weight of the right ventricle (RV) to the body weight (BW), RV/BW, in the hypoxia groups increased significantly as compared with those of the control groups. The amount of immunoreactive FN in the right ventricle increased significantly in the hypoxia groups after exposure to hypoxia environment for 15 days (10.31% +/- 2.15%, mean +/- S.D.) and for 30 days (9.55% +/- 1.65%) as compared with those in the day 0 control group (3.05% +/- 1.15%, p < 0.01), the day 15 control group (3.26% +/- 0.83%, p < 0.01), and the day 30 control group (3.19% +/- 0.51%, p < 0.01). However, there were no significant changes in the amount of immunoreactive FN in the left ventricle of the hypoxia groups as compared with the control groups. These results suggest that chronic hypoxia may lead to an increase of FN in the hypertrophied right ventricle but not in the left ventricle, which indicates that pulmonary hypertension induced by chronic hypoxia rather than chronic hypoxia itself is a major cause for the increase of FN in the myocardium. The increased FN in the right ventricle may accelerate the accumulation of collagen and, in turn, contribute to the increase of the myocardial stiffness and eventually to the diastolic dysfunction of the hypertrophied right ventricle induced by chronic hypoxia.     

实时三维超声心动图技术评估正常成年人右室收缩功能

目的：用经胸实时三维超声心动图技术（RT-3DE）评估正常人右室整体及节段收缩功能;并与左室三维及传统方法相比较,评价三维测量右室每搏输出量（RVSV）的准确性。方法34例正常成人,行经胸左、右心室RT-3DE图像采集,脱机分析右室整体及流出道（RV-outflow）、体部（RV-body）和流入道（RV-inflow）节段容积参数和射血分数（RVEF）,左室整体三维容积参数和射血分数（LVEF）。同时用传统M型Teichholtz方法测量LVSV和LVEF;用右室流出道流速曲线速度时间积分（VTI）方法估测RVSV。分析3种方法测得SV的相关性。结果34例正常人三维方法测得的RVSV 与三维方法测得的LVSV相关性较高（r=0.86,P〈0.001）;与Teichholtz方法测得的LVSV相关性较差（r=0.31,P〈0.001）;与右室流出道VTI方法测得的RVSV相关性较差（r=0.46,P〈0.001）;二维和流速曲线方法测值均较三维方法偏高（P〈0.05）。右室各节段收缩强度存在差异,节段EF值（%）流入道（62.00±7.20）＞流出道（53.08±14.10）＞体部（32.00±11.08）（P〈0.05）。右室三维整体收缩功能参数经体表面积标化后,不同性别间未见显著统计学差异。结论RV-3DE方法评估正常成人LVSV、RVSV一致性好,相关性较高。正常人右室流入道的收缩活动强度及对整体每搏输出量的贡献占主要地位,其次是流出道、体部。RT-3DE为研究右室整体和节段收缩功能提供了可靠、无创的新方法。     

正常人心肌应变及应变率定量分析

目的 定量研究我国成年人心肌应变及应变率的正常值范围、心肌各节段之间的差异，以及与年龄和性别的关系。方法 应用GE Vivid 7超声仪及Q-analyze软件对50例健康者左右心室心肌各节段进行应变和应变率定量分析。结果 左室基底段、中间段和心尖段的应变和应变率依次递减，基底段最大，心尖段最小。左室基底段室间隔、前壁、后壁、下壁和侧壁的应变和应变率差异无显著性意义。右室中间段的应变和应变率最大，右室基底段的应变大于左室，右室中间段和心尖段的应变和应变率测量值均明显大于左室，性别和年龄对左右心室肌应变和应变率的影响不大。结论 应变或应变率成像能够定量分析局部心肌的变形，为临床评价心功能提供了又一有效工具。     

Normal regional right ventricular function and its change with age: a Doppler myocardial imaging study.

BACKGROUND: Doppler Myocardial Imaging (DMI) is a new technique currently being studied for the assessment of regional systolic and diastolic left ventricular (LV) function. No normal values or data on age-related changes in regional myocardial right ventricular (RV) velocities are available. METHODS AND RESULTS: Color DMI was used in 32 healthy volunteers (aged 16-76 years) to derive regional velocities from basal, medial, and apical segments of the RV free wall in the apical 4-chamber view, and from distal segments as well as from the tricuspid annulus in the parasternal long-axis view. Both mitral annular and regional LV velocities (4-chamber, long-axis parasternal view) were also recorded and compared with corresponding RV regional velocities. The M-mode displacement of the cardiac base was measured. Corresponding RV and LV DMI data sets were compared. For longitudinal function, RV free wall systolic velocities were consistently higher than velocities recorded in corresponding LV segments (analysis of variance, P <.05). Older subjects (40-76 years; 13 men, 2 women) had lower RV long-axis regional velocities than younger subjects (16-39 years; 15 men, 2 women), but had higher short-axis RV systolic velocities. For diastolic velocities, a negative correlation between age and the ratio of regional early diastolic to late diastolic velocity was shown for all RV free wall segments (eg, basal segment: r = -0.63, P <.0001). CONCLUSIONS: The right ventricle has higher long-axis regional velocities, a greater excursion of its lateral atrioventricular valve ring, and reduced circumferential shortening velocities compared with the left ventricle. Right ventricular longitudinal shortening is dominant over short-axis function in healthy young subjects. Normal age-related changes of diastolic velocities for each segment of the normal RV free wall have been defined.     

Echocardiographic evaluation of fetal hydrothorax: the effusion ratio as a diagnostic tool.

OBJECTIVE: Fetal hydrothorax may lead to hydrops and is associated with mortality as high as 50%. The objective of this study was to define the pathophysiology of fetal hydrothorax and its relation to hydrops. METHODS: Measurements from echocardiograms of 33 fetuses diagnosed with hydrothorax were made, and included diameters of the thorax, heart, inferior vena cava, right ventricle (RV), left ventricle (LV) and aortic and pulmonary valves. Doppler-derived velocities were measured in the aorta and pulmonary artery just above the aortic and pulmonary valves. The ratio of the area of the effusion to the area of the thorax (effusion ratio) was calculated. Variables were converted into Z-scores from regression equations based on normal data. Features of fetuses with and without hydrops were compared. RESULTS: Higher effusion ratios were noted in hydropic versus non-hydropic fetuses. Compared to a normal population, study subjects had smaller dimensions of LV, RV and aortic and pulmonary valves. They also had higher pulmonary artery peak velocities. The comparison between non-hydropic and hydropic fetuses revealed lower values for LV and pulmonary valve dimensions, and peak aortic velocity in hydropic fetuses. The severity of LV compression correlated significantly with effusion ratio. CONCLUSION: Fetal hydrothorax is accompanied by compression of the cardiac structures, resulting in altered cardiac hemodynamics. Echocardiographic assessment, including the measurement of effusion ratio, may be a useful tool in guiding fetal therapy.     

The importance of the maximum pulmonary artery regurgitant velocity following repair of tetralogy of Fallot: a pilot study

Background: Tetralogy of Fallot repairs invariably result in pulmonary regurgitation with the long term sequelae of ventricular dilatation and dysfunction. Objective: The purpose of this study is to correlate pulmonary flow parameters with right ventricular size and function. Materials and methods: Pulmonary artery velocity was mapped by magnetic resonance flow analysis in seven children with pulmonary regurgitation following tetralogy of Fallot repair. Right and left ventricular volumes were determined by Simpson's rule from double oblique cine gradient echo images of the heart. The ejection fraction was calculated for each ventricle. Right ventricular enlargement was normalized for patient size by calculating the ratios of right ventricle end diastolic and end systolic volumes to the left ventricle end diastolic and end systolic volumes respectively (EDV RV:LV and ESV RV:LV). The maximum pulmonary artery antegrade and retrograde velocities and the ratio of the time for antegrade to regurgitant flow were compared to ventricular function and volume measurements by regression analysis. Results: A significant linear relationship between the maximum regurgitant pulmonary artery velocity and EDV RV:LV was identified (r ² = 0.82). Conclusion: An elevated maximum pulmonary regurgitant velocity correlated well with the degree of right ventricular enlargement in patients following tetralogy of Fallot repair. If the results are verified by a larger study, the maximum pulmonary regurgitant velocity may be substituted for the more cumbersome direct measurement of right ventricular size.