超声心动图对马凡氏综合征患者的右心室收缩功能的评价

目的用超声心动图评价成年马凡氏综合征（Marfan syndrome,MFS）患者是否存在右心室收缩功能不全。方法41例MFS患者及43例正常对照者行M型、二维及组织多普勒超声心动图。记录三尖瓣环收缩期位移（tricuspid annular plane systolic excursion,TAPSE）、右心室面积缩小率（fractional are achange,FAC）及组织多普勒三尖瓣环收缩速度（S。）。结果MFS患者右心室收缩功能指标虽处于正常范围,但均低于正常对照[TAPSE：（21±2）mm口s．（26±1）mm,P〈O．01;FAC：36％±2％vs．42％±3％,P〈O．01;Su：（12±0．3）cm／svs．（16±0．9）cm／s,P〈0．01]。结论MFS患者存在右心室收缩功能不全,提示MFS可能累及右心室心肌。     

Exercise capacity in hypertrophic cardiomyopathy depends on left ventricular diastolic function.

Some studies have demonstrated that left ventricular (LV) diastolic function is the principal determinant of impaired exercise capacity in hypertrophic cardiomyopathy (HC). In this study we sought the capability of echocardiographic indexes of diastolic function in predicting exercise capacity in patients with HC. We studied 52 patients with HC while they were not on drugs;12 of them had LV tract obstruction at rest. Diastolic function was assessed by M-mode and Doppler echocardiography by measuring: (1) left atrial fractional shortening, and the slope of posterior aortic wall displacement during early atrial emptying on M-mode left atrial tracing; and (2) Doppler-derived transmitral and pulmonary venous flow velocity indexes. Exercise capacity was assessed by maximum oxygen consumption by cardiopulmonary test during cycloergometer upright exercise. Maximum oxygen consumption correlated with the left atrial fractional shortening (r = 0.63, p <0.001), the slope of posterior aortic wall displacement during early atrial emptying (r = 0.55, p <0.001), age (r = -0.50; p <0.001), pulmonary venous diastolic anterograde velocity (r = 0.41, p <0.01), and the systolic filling fraction (r = -0.43; p <0.01). By stepwise multiple linear regression analysis, left atrial fractional shortening and the pulmonary venous systolic filling fraction were the only determinants of the maximum oxygen consumption (multiple r = 0.70; p <0.001). Exercise capacity did not correlate with Doppler-derived transmitral indexes. Thus, in patients with HC, exercise capacity was determined by passive LV diastolic function, as assessed by the left atrial M-mode and Doppler-derived pulmonary venous flow velocities.     

Right ventricular long axis function in adults and children with Ebstein's malformation

OBJECTIVES: To assess right ventricular function in adults and children with Ebstein's anomaly. Design: Prospective study. Setting: Tertiary referral centre. SUBJECTS: Fifteen patients (8 adults and 7 children) with Ebstein's anomaly and 14 healthy controls. Interventions: Transthoracic echocardiography was performed in all. Right ventricular function was assessed from long axis M-mode recordings of the right atrio-ventricular free wall. Total systolic excursion as well as peak shortening and lenghtening rates of the right ventricle were measured. RESULTS: Children and adult patients with Ebstein's anomaly differed in terms of age at diagnosis, the adult group having been diagnosed later 19.8+/-15.8 vs. 5.9+/-6.2 years, P<0.05. Measures of right ventricular long axis function in children with Ebstein's anomaly showed a significantly reduced systolic excursion 1.4+/-0.4 vs. 2.4+/-0.53 cm, P<0.05 and peak lenghtening rate; early 8.04+/-4.3 vs. 11.8+/-2.4 cm/s and late 6.14+/-3.6 vs. 10.6+/-4.3 cm/s, P=0.05 compared to controls. In contrast, measurements of right ventricular long axis function in adults with Ebstein's anomaly showed no significant difference when compared to the control group. Transtricuspid Doppler flow velocities were not different between patient's groups and corresponding controls. CONCLUSION: The right ventricle assessed by this simple, non-invasive technique reveals a significantly reduced systolic and diastolic function in children with Ebstein's malformation compared to controls but a 'normal' right ventricular function comparable to controls in adult patients. Significant right ventricular dysfunction in children with Ebstein's anomaly could account for their earlier presentation. Long term follow up of the right ventricular abnormalities is needed in such children to discover more about the natural history of the disease.     

Right ventricular dysfunction due to right ventricular outflow tract patch

Doppler tissue imaging analysis was used to examine the relationship between right ventricular function and right ventricular outflow tract damage in 54 patients with repaired tetralogy of Fallot. The patients were divided into three groups: 16 in whom the right ventricular outflow tract was directly sutured (group DS), 23 who had transventricular patch repair (group TVP), and 15 who had transannular patch repair (group TAP). The control group consisted of 16 age-matched patients who underwent patch closure of a ventricular septal defect (group C). The Tei index was obtained from tricuspid and pulmonary Doppler flow velocities. The right ventricular Tei index was significantly greater in groups TVP and TAP than in group DS. Doppler tissue imaging analysis in groups TVP and TAP showed shorter myocardial systolic velocity, diastolic peak velocity, and atrial diastolic peak velocity, lower peak myocardial velocity and acceleration during isovolumic contraction, and prolonged isovolumic relaxation and contraction times compared to groups DS and C. Right ventricular dysfunction is due to the right ventricular outflow tract patch. Thus, the right ventricular outflow tract may be essential for right ventricular ejection and maintenance of right ventricular function.     

Assessment of the normal adult right ventricular diastolic function using M-mode echocardiographic measurement of tricuspid ring motion

Right ventricular function can be evaluated echocardiographically by assessing the longitudinal motion of the tricuspid ring recorded in the apical four chamber view. In this study, we applied this technique to assess the right ventricular diastolic function in 10 healthy Japanese men (mean age : 28±6 years; age range : 20–43 years). Echocardiographic studies were performed with a phased-array imaging system using a 2.5 MHz probe. Tricuspid ring motion was measured by two-dimensional echo guided M-mode echocardiogram of the right lateral tricuspid ring. The excursion of the tricuspid ring during early diastole (dS; mm) and the peak rate of change of the excursion (dS/dt; mm/sec) were measured. We also assessed the right ventricular function by cine magnetic resonance imaging (MRI). Cine gradient echo images were obtained along the short axis of the right ventricle. The right ventricular volume at each phase of the cardiac cycle was calculated by Simpson's method and time–volume curves were constructed. The peak filling rate (dV/dt; ml/s) was determined from these time–volume curves. The dS was 12.8±2.5 mm, dS/dt was 132±27 mm/sec and dV/dt was 269±66 ml/s. There were significant positive correlations between dS and dV/dt (r=0.80, P<0.01), and between dS/dt and dV/dt (r=0.45, P<0.05). Based on our results, M-mode echocardiographic measurements of tricuspid ring motion may be used to assess the right ventricular diastolic function.     

右心室不同部位起搏对左心室收缩功能的影响

目的:比较右心室心尖(RVA)及流出道间隔部(RVOT-S)起搏对左心室收缩功能的影响,探讨合理的右心室起搏部位。方法:自2007年8月~2009年12月,36例左室收缩功能正常的完全性房室传导阻滞患者,随机纳入RVA和RVOT-S起搏组,起搏器植入12月后分别测定左室射血分数(LVEF),左室收缩末容量(LVESV),主动脉瓣口速度时间积分(VTI),主动脉与肺动脉瓣开放时间差(QAO-QP),房颤负荷(AFb),自动模式转换(AMS),血浆脑钠尿肽原(NT-proBNP)变化,QRS波宽度,比较两组的差别。结果:起搏12月后RVOT-S组LVEF及VTI明显高于RVA组(均P<0.05);LVESV,QAO-QP,NT-BNP,AFb,AMS及QRS波宽度明显低于RVA组(均P<0.05)。结论:与RVOT-S组相比,RVA长期起搏可导致明显左右心室间以及左室内收缩不同步及左室重构,减低左心室收缩功能,对心室依赖起搏患者应首选RVOT-S为心室电极植入部位。     

Determinants and clinical significance of natriuretic peptides and hypertrophic cardiomyopathy.

AIMS: Atrial and brain natriuretic peptide levels closely reflect impaired left ventricular function in patients with heart failure. In the present study we assessed the determinants and the clinical significance of atrial and brain natriuretic peptide plasma levels in hypertrophic cardiomyopathy. METHODS AND RESULTS: In 44 patients with hypertrophic cardiomyopathy (40+/-15 years) we evaluated: (a) atrial and brain natriuretic peptide plasma levels; (b) left ventricular hypertrophy; (c) left ventricular ejection fraction; (d) transmitral and pulmonary venous flow velocity patterns, and left atrial fractional shortening; (e) left ventricular outflow tract gradient; (f) maximal oxygen consumption. Left ventricular hypertrophy influenced only brain natriuretic peptide levels (r=0.32;P<0.05). Atrial and brain natriuretic peptide plasma levels did not correlate with left ventricular ejection fraction, but correlated with left ventricular outflow tract gradient (r=0.35;P<0.05; and r=0.40, P=0.022, respectively) and left atrial fractional shortening (r=-0.57;P<0.001, and r=-0.35;P<0.05, respectively). Atrial but not brain natriuretic peptide plasma levels were inversely related to maximal oxygen consumption (r=-0.35;P<0.05). By stepwise multiple regression analysis, left atrial fractional shortening and left ventricular outflow tract gradient were the only predictors of atrial and brain natriuretic peptide plasma levels, respectively. CONCLUSIONS: In hypertrophic cardiomyopathy, atrial natriuretic peptide plasma levels are mainly determined by diastolic function: this explains the relationship with exercise tolerance. In contrast, brain natriuretic peptide plasma levels are mainly determined by left ventricular outflow tract gradient.     

An abnormal right ventricular apical angle is indicative of global right ventricular impairment

The presence of right ventricular (RV) dysfunction is an adverse prognostic indicator but current echocardiographic methods have some limitations. RV apical angles in systole and diastole were correlated with known parameters of RV function in patients without pulmonary hypertension (Group 1) and in patients with pulmonary hypertension (Group 2). RV apical angles were significantly smaller in both systole (22 +/- 7 degrees) and diastole (33 +/- 6 degrees) in Group 1 patients when compared to Group 2 (54 +/- 18 degrees, p < 0.0001 and 59 +/- 17 degrees, p < 0.0001, respectively). RV apical angles, both in systole and diastole, were strongly correlated with RV end-systolic area (R = 0.89, p < 0.0001) and end-diastolic area (R = 0.81, p < 0.0001), respectively. Similarly, the apical systolic and diastolic angle correlated well with decreased tricuspid annular plane systolic excursion (TAPSE, R = -0.76 and R = -0.73, p < 0.001) as well as with decreased RV fractional area change (R = -0.81 and R = -0.77, p < 0.001). Therefore, we conclude that this new measurement of RV apical angle is simple and useful to quantify RV apical structural and functional abnormalities that are well correlated with global RV impairment in patients with chronic pulmonary hypertension.     

右心室流出道间隔部起搏对左心室功能的影响

目的比较右心室流出道间隔部(RVOT)起搏与右心室心尖部(RVA)起搏的血流动力学差异;评估RVOT起搏技术的可行性与安全性。方法选择有永久起搏器置入适应证的患者75例。根据术者建议和患者意愿分为RVOT组(40例)和RVA组(35例)。所有房室传导阻滞及病窦综合征合并一度房室传导阻滞患者采用双腔起搏双腔感知触发抑制型起搏模式,心房颤动伴长间歇患者采用抑制型心室按需起搏模式。比较2组的血流动力学差异。结果 RVOT组的QRS波宽度较RVA组缩窄(23.2±28.7)ms,差异有统计学意义(P<0.01)。与RVA组比较,RVOT组LVEF、左心室短轴缩短率明显升高,左心室舒张末容积明显下降(P<0.05,P<0.01)。与术前比较,RVA组LVEF、左心室短轴缩短率明显下降,左心室舒张末容积明显升高,差异有统计学意义(P<0.01)。结论利用螺旋电极进行RVOT起搏可行且较为安全。RVOT起搏的血流动力学参数优于RVA。     

Echo derived variables predicting exercise tolerance in patients with dilated and poorly functioning left ventricle

OBJECTIVE: To determine whether resting echo derived measurements predict exercise tolerance and its interrelation with heart rate response and ventilation drive in patients with systolic left ventricular disease. DESIGN: Prospective echocardiographic examination followed by cardiopulmonary exercise testing. SETTING: A tertiary referral centre for cardiac diseases. SUBJECTS: 21 patients (11 with coronary artery disease, 10 with idiopathic dilated cardiomyopathy) with end diastolic dimension > 6.4 cm, shortening fraction < 25%, and in sinus rhythm. There were 11 age matched normal controls. RESULTS: In the patients, peak oxygen consumption (mVo2) correlated with right ventricular long axis excursion (r = 0.62); 65% of the variance in mVo2 was predictable using a multivariate model with right ventricular long axis excursion and peak lengthening rate, and peak mitral atrial filling velocity as independent variables. Aetiology was not an independent predictor, although the right ventricular long axis excursion (mean (SD)) was greater in patients with idiopathic dilated cardiomyopathy than in those with coronary artery disease (2.4 (0.5) cm v 1.6 (0.5) cm, p < 0.001). Peak heart rate correlated with duration of mitral regurgitation (r = -0.52) and the slope of ventilation against CO2 production correlated with M mode isovolumic relaxation time (r = 0.61). CONCLUSIONS: In patients with systolic left ventricular dysfunction, more than half the variance in exercise tolerance can be predicted by factors measured on echocardiography at rest, particularly right ventricular long axis excursion.     

Abnormal regional left ventricular mechanics in treated hypertensive patients with 'normal left ventricular function'

Global systolic and diastolic LV function assessed by conventional echocardiographic indices is often normal in patients with controlled hypertension, with or without left ventricular hypertrophy. However, it is not certain whether regional myocardial function in these patients remains normal. We investigated 26 patients and 10 age matched normal controls, by means of long axis M-mode echocardiography. There was no significant difference in age, sex distribution, heart rate, blood pressure and routine ECG measurements between the two groups. Although there was significant LVH in patients compared to normal controls, LV cavity size and global systolic function, assessed by shortening fraction, ejection fraction and mean velocity of circumferential fibre shortening did not differ between the two groups, nor did LV diastolic function, assessed by the mitral flow pattern. However, LV regional mechanics, as assessed by multiple long axis M-mode echocardiograms differed significantly, in both systole and diastole, between the two groups. Compared to controls, the total longitudinal systolic excursion in both LV free wall and ventricular septum were significantly reduced in patients, and so was maximum early relaxation and atrial contraction in the LV free wall. The mean rate of systolic excursion in all 3 sites did not differ between the two groups, but the mean rate of early relaxation in both LV free wall and ventricular septum was significantly decreased in patients compared to normal controls. In conclusion, the evaluation of LV dysfunction in patients who have achieved good blood pressure control requires more than a conventional echocardiographic assessment. The assessment of regional mechanics described in the present paper offers an easy and sensitive method for the detection of subtle signs of LV mechanical inefficiency associated with LVH.     

The relationship between systolic anterior motion of the mitral valve and the left ventricular outflow tract Doppler in hypertrophic cardiomyopathy

In an attempt to investigate the role of left ventricular blood outflow in the generation of systolic anterior motion (SAM) of the mitral valve in patients with hypertrophic cardiomyopathy, we precisely analyzed the temporal relation of SAM and the left ventricular outflow tract (LVOT) systolic Doppler events obtained at the maximal mitral-septal apposition or equivalent area in eight patients with severe SAM, in five patients with mild/moderate SAM, and in seven patients with no SAM, using M-mode and pulsed Doppler echocardiography; the results were compared with those in 10 normal subjects. In all 13 patients with SAM, the timing of SAM generation corresponded to the LVOT Doppler events either between the onset of SAM and the onset of Doppler (r = 0.834, p less than 0.0001) or between the peak of SAM and the peak of Doppler (r = 0.836, p less than 0.0001). The excursion rate of the development of SAM showed a correlation with the LVOT blood outflow acceleration (r = 0.828, p less than 0.0001). The timing of SAM resolution also correlated with the Doppler events, either between the offset of SAM and the offset of Doppler (r = 0.795, p less than 0.001) or the end of SAM and the end of Doppler (r = 0.859, p less than 0.0001). The LVOT blood outflow deceleration showed a correlation with the regression rate of SAM (r = 0.668, p less than 0.013). The LVOT blood outflow acceleration was significantly higher in patients with severe SAM than in patients with mild/moderate SAM or no SAM. This study suggests that the high LVOT blood outflow acceleration in early systole possibly plays an important part in the generation of the Bernoulli pressure drop and results in anterior motion of the mitral valve. At mid-systole, a drag force and/or suction effect of pressure drop produced by continuous outflow blood may sustain the anterior motion of the mitral valve. At late systole, as the blood flow decelerates, the regression of SAM then occurs.     

Clinical value of echocardiography in evaluating hemodynamics and right ventricular function in patients with chronic thromboembolic pulmonary hypertension after balloon pulmonary angioplasty

BackgroundPatients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) are eligible for balloon pulmonary angioplasty (BPA). However, the short-term effects of BPA on pulmonary hemodynamics and right ventricular (RV) function in patients with CTEPH have not been elucidated. In the current study, echocardiography was conducted to explore the short-term effects of BPA on inoperable CTEPH patients.MethodsA total of 30 inoperable CTEPH patients who underwent echocardiography before and after BPA were enrolled to the present retrospective study. Right heart catheterization (RHC) parameters, echocardiography function parameters, and echocardiography structural parameters of patients were evaluated at baseline and within 24 hours after BPA and the results were compared.ResultsRHC parameters including pulmonary artery systolic pressure (PASP), pulmonary artery diastolic pressure (PADP), mean pulmonary artery pressure (mPAP), and pulmonary vascular resistance (PVR), and echocardiography structural parameters including right atrium diameter (RAD), right ventricular end-diastolic area (RVEDA), right ventricular end-systolic area (RVESA), right atrium end-diastolic area (RAEDA) and right atrium end-systolic area (RAESA) significantly improved within 24 h after BPA compared with the baseline results (P<0.05). However, there were no significant differences in echocardiography function parameters including tissue Doppler-derived tricuspid lateral annular systolic velocity (S’), tricuspid annular plane systolic excursion (TAPSE), right ventricular index of myocardial performance (RIMP), right ventricular fractional area change (RVFAC) and left ventricular stroke volume (LVSV) before and after BPA.ConclusionsThe findings show that a single BPA procedure significantly improves RV volume load and reduces the pulmonary blood pressure in CTEPH patients in the short-term. However, BPA does not improve RV systolic function 24 hours after the procedure. The results indicate that evaluation of RV structural and function with echocardiography is an effective approach for non-invasive monitoring of patient status after BPA.     

Cardiac magnetic resonance imaging findings in patients with right ventricular outflow tract premature contractions

AIMS: To assess prospectively the value of cardiac magnetic resonanceimaging in patients with apparently idiopathic premature contractionsarising from the right ventricular outflow tract. METHODS: We compared magnetic resonance imaging scans in 19 patients(13 males and six females, mean age 44 years) with frequent(>100 per hour), monomorphic (left bundle branch block andinferior axis morphology) extrasystoles, and in 10 volunteers(four males and six females, mean age 36·7 years) withoutstructural heart disease. Magnetic resonance imaging studies(1 or 1·5 Tesla) included spinecho and gradient-echosequences in the standard planes. The presence of structuraland dynamic abnormalities of the right and left ventricles,such as reduced wall thickness, systolic bulging, and decreasedsystolic thickening, were evaluated. In addition, end-diastolicdiameters of the right ventricular outflow tract were measuredin the transverse plane. RESULTS: The dimensions of the right ventricular outflow tract were widerin patients with extrasystoles compared to the control group.Mean anteroposterior and transverse diameters were 39·6±4·6mm vs 29·9±4·8 mm (P<0·01) and27·5±3·8 mm vs 20·5±2·5mm (P<0·01), respectively. Wall motion and morphologicalabnormalities were present in 16/19 (84%) patients, and wereconfined to the anterolateral wall in 15/16 cases. All normalsubjects had normal magnetic resonance imaging findings (P=0·008). CONCLUSIONS: Cardiac magnetic resonance imaging revealed that in patientswith idiopathic right ventricular outflow tract premature contractionsthere was a higher rate of morphological and functional abnormalitiesof the right ventricular outflow tract than in the normal subjects.Large studies and long follow-up are needed to confirm whetherthese findings could help identify a localized form of arrhythmogeniccardiomyopathy, and its clinical significance.     

Altered Right Ventricular Contractile Pattern after Cardiac Surgery: Monitoring of Septal Function Is Essential

Assessment of right ventricular (RV) function is important in the management of various forms of cardiovascular disease. Accurately assessing RV volume and systolic function is a challenge in day‐to‐day clinical practice due to its complex geometry. Tricuspid annular plane systolic excursion (TAPSE) and systolic excursion velocity (S′) have been reviewed to further assess their suitability and objectivity in evaluating RV function. Multiple studies have validated their diagnostic and prognostic values in numerous pathologic conditions. Diminished longitudinal contraction after cardiothoracic surgery is a well‐known phenomenon, but it is not well validated. Despite significant reduction in RV performance along the long‐axis assessed by TAPSE and S′ after cardiac surgery, RV ejection fractions did not change as well as the left ventricular parameters and exercise capacity. RV contractile patterns were markedly altered with decreased longitudinal shortening and increased transverse shortening, which are likely resulted from the septal damage during cardiac surgery. The septum is essential for RV performance due to its oblique fiber orientation. This allows ventricular twisting, which is a vital mechanism against increased pulmonary vascular resistance. The septum function along with TAPSE and S′ should be adequately assessed during cardiac surgery, and evidence of septal dysfunction should lead to reevaluation of myocardial protection methods.     

Diagnosis of ischemic right ventricular dysfunction by M-mode echocardiography

The importance of right ventricular infarction depends uponthe presence and severity of the resultant ischemic right ventriculardysfunction. The usefulness of M-mode echocardiography for thediagnosis of ischemic right ventricular dysfunction was investigatedin 63 patients with acute myocardial infarction. Group A included35 patients with ischemic right ventricular dysfunction, andGroup B 28 patients without ischemic right ventricular dysfunction.The diagnosis of ischemic right ventricular dysfunction wasmade when the right atrial pressure was higher than 10 mm Hgand greater than, equal to or not more than 5 mm Hg less thanpulmonary capillary pressure. Right ventricular diastolic dimension was greater in Group Athan in Group B (P<0.01). The upper 95% confidence limitof this parameter was found to be 18 mm/m² in Group B. The rightventricular/left ventricular diastolic dimension ratio was greaterin Group A than in Group B (P <0.01). The upper limit ofthis ratio in Group B was 0.63. When either of these two criteria was present (right ventriculardiastolic dimension 18 mm/m² or right ventricular/left ventriculardiastolic dimension0.63), the diagnosis of ischemic right ventriculardysfunction could be made in 19 of 35 patients (sensitivity54.2%), with no false positives (specificity 100%). The interventricular septum was rapidly displaced upwards atthe beginning of systole and downwards during diastole in eightpatients from Group A, and in no patient from Group B. M-mode echocardiographic indices of right ventricular dilatationmay be of value in the diagnosis of ischemic right ventriculardysfunction, but their sensitivity is low. The discrepancy betweenhemodynamic and M-mode echocardiographic parameters of ischemicright ventricular dysfunction may be attributed to impairmentof right ventricular compliance, with a right ventricular diastoledimension/right atrial pressure ratio greater in Group B thanin Group A (P< 0.01).     

Assessment of right and left ventricular function in terms of force development with gestational age in the normal human fetus.

OBJECTIVE--To assess right and left ventricular systolic function in normal human fetuses by cross sectional Doppler echocardiography to calculate the force developed by myocardial shortening. DESIGN--Cross sectional echocardiographic images of the aorta and pulmonary arteries were obtained prospectively in order to measure great vessel diameters and calculate their cross sectional areas. Doppler velocity signals were recorded from the proximal aorta and the proximal pulmonary artery and digitised to obtain peak velocity, acceleration time, flow velocity time integral during acceleration, and the flow velocity time integral for the whole of ejection. Right and left ventricular force development was estimated by Newton's equation in which force is defined as the product of mass and acceleration. PATIENTS--58 normal human fetuses at a gestational age of from 20 to 42 weeks. RESULTS--The cross sectional area of the pulmonary artery was 20% greater than that of the aorta. Aortic acceleration time was longer than that in the pulmonary artery, and peak blood flow velocity in the aorta was consistently greater than that in the pulmonary artery. Right ventricular stroke volume was significantly greater than left ventricular stroke volume. The force developed by the right and left ventricles was, however, similar throughout the gestational period studied, increasing tenfold from 20 weeks' gestation to term (r = 0.74, p less than 0.0001; r = 0.75, p less than 0.0001) respectively. CONCLUSION--The development of right and left ventricular force in the human fetus is similar in spite of the greater volume handled by the right ventricle. This index of ventricular performance does not require calculation of ventricular volume and because it varies independently of ventricular geometry and heart rate it should prove useful in assessing cardiac function in the normal human fetus and in fetuses with ventricular dysfunction.     

Assessment of right and left ventricular function in terms of force development with gestational age in the normal human fetus.

OBJECTIVE--To assess right and left ventricular systolic function in normal human fetuses by cross sectional Doppler echocardiography to calculate the force developed by myocardial shortening. DESIGN--Cross sectional echocardiographic images of the aorta and pulmonary arteries were obtained prospectively in order to measure great vessel diameters and calculate their cross sectional areas. Doppler velocity signals were recorded from the proximal aorta and the proximal pulmonary artery and digitised to obtain peak velocity, acceleration time, flow velocity time integral during acceleration, and the flow velocity time integral for the whole of ejection. Right and left ventricular force development was estimated by Newton's equation in which force is defined as the product of mass and acceleration. PATIENTS--58 normal human fetuses at a gestational age of from 20 to 42 weeks. RESULTS--The cross sectional area of the pulmonary artery was 20% greater than that of the aorta. Aortic acceleration time was longer than that in the pulmonary artery, and peak blood flow velocity in the aorta was consistently greater than that in the pulmonary artery. Right ventricular stroke volume was significantly greater than left ventricular stroke volume. The force developed by the right and left ventricles was, however, similar throughout the gestational period studied, increasing tenfold from 20 weeks' gestation to term (r = 0.74, p less than 0.0001; r = 0.75, p less than 0.0001) respectively. CONCLUSION--The development of right and left ventricular force in the human fetus is similar in spite of the greater volume handled by the right ventricle. This index of ventricular performance does not require calculation of ventricular volume and because it varies independently of ventricular geometry and heart rate it should prove useful in assessing cardiac function in the normal human fetus and in fetuses with ventricular dysfunction.     

Evolution of ventricular function during permanent pacing from either right ventricular apex or outflow tract following AV-junctional ablation for atrial fibrillation.

AIMS: To compare acute and chronic ventricular function between patients, without cardiac failure, paced at either right ventricular apex or outflow tract. METHODS: Twenty patients. 10 paced apically and 10 in the outflow tract, underwent two radionuclide ventriculograms. Eight parameters of systolic or diastolic function were compared at each assessment, as were changes within each group over time. RESULTS: No differences were identified in systolic function between pacing sites 6 weeks after pacing or 23 weeks later. Peak filling rate was lower (P=0.04) at the second assessment with outflow tract pacing. No other diastolic differences were identified. Between assessments, time to peak filling rate prolonged (P=0.04) with apical pacing, while left ventricular area reduced (P=0.04) and peak filling rate decreased (P=0.04) with outflow tract pacing. Septal motion was better preserved with outflow tract pacing. No other parameter changed over time. ECG measures were similar at 14.7 months. CONCLUSIONS: No major differences were identified in systolic function between pacing sites. Some systolic parameters were better preserved with outflow tract pacing and diastolic function deteriorated subtly over time in both groups. Right ventricular pacing adversely affects left ventricular function.     

高迁移率族蛋白B1在新生儿持续肺动脉高压中的变化及临床意义

目的 观察高迁移率族蛋白B1(HMGB1)在新生儿持续肺动脉高压(PPHN)中的变化,并探讨其临床意义.方法 62例PPHN患儿根据肺动脉收缩压(PASP)分为轻度组(n=22例)、中度组(n=21例)和重度组(n=19例),同期选择20例正常新生儿作为对照组.检测和比较PPHN患儿及正常新生儿出生时血清HMGB1水平...