The influence of heart rate and age on diastolic blood flow velocity in the left ventricular inflow tract

To investigate the relationship between age-related blood flow velocity and heart rate in the left ventricular inflow tract, we studied 118 healthy volunteers (age greater than 15 years). The maximal velocity (Vmax) of the transmitral diastolic flow during early ventricular filling (E) and during filling due to atrial contraction (A) was measured at 3 sites in the left ventricle with pulsed Doppler echocardiography. At all these sites a significant positive correlation was found between the VmaxA and the EA ratio and the interaction of heart rate and age. VmaxA increases if age and heart rate increase. The influence of the interaction of age and heart rate on VmaxA is most pronounced near the mitral annulus. VmaxA is only related to age and decreases with advancing age. Our observations contribute to the explanation of the more important role of the atrial contraction in the elderly.     

The relationship between fetal heart rate and Doppler blood flow velocity waveforms

The degree of fetal heart rate dependency of pulsatility index measurements in the fetal descending aorta, internal carotid artery, and umbilical artery was studied relative to quiet and active sleep states in normal and growth-retarded fetuses at 37-38 weeks of gestation. In all vessels an inverse relationship between pulsatility index and heart rate was established. The degree of this inverse relationship varies proportionally with the level of peripheral vascular resistance in the vessels studied.     

健康老年人米餐后脑血流速度及血压心率的变化

目的　研究健康老年人米餐后脑血流速度及血压、心率变化规律。方法　测定 30例健康老人[平均年龄 (70± 3)岁 ]米餐前后脑血流速度 (CFV)、血压及心率变化指标。结果　米餐后脑血流速度较米餐前显著减慢 (P <0 0 1) ,动脉血压略有下降 ,心率略快 (P >0 0 5 )。结论　米餐 30min后老年人脑血管收缩期和部分脑血管舒张期血流量减少 ,心率及血压无明显变化。     

Impact of milrinone on mitral annular velocity in patients with congestive heart failure

Purpose

The purpose of this study is to assess the impact of milrinone on mitral annular velocity in patients with congestive heart failure.

Method

We studied 27 patients with congestive heart failure. All patients underwent transthoracic echocardiography both before and after administration of milrinone. We measured the early transmitral velocity (E) and the mitral annular early diastolic velocity (Ea). The ratio of E to Ea (E/Ea) was calculated. After the baseline echocardiography, milrinone was administered as a continuous infusion at a rate of 0.25 μg/kg/min. Echocardiographic measurements were repeated 4 h after milrinone was begun.

Results

After administration of milrinone, Ea was significantly increased, while E/Ea was significantly decreased. The population of 27 patients was divided into 20 (74 %) with left ventricular ejection fraction (LVEF) <50 % and seven (26 %) with LVEF ≥50 %. Ea was significantly increased in both groups, while E/Ea was significantly decreased.

Conclusion

Even low-dose milrinone produced an improvement in left ventricular (LV) diastolic function, as evidenced by an increase in Ea, and falls in LV filling pressures, as determined by a decrease in E/Ea, in patients with congestive heart failure throughout a wide range of LV systolic function.     

二尖瓣血流传播速度估测左心室舒张功能影响因素的研究

目的 探讨超声心动图色彩反转速度及切面选择对二尖瓣血流传播速度(Vp)测定结果的影响。方法 在33例先天性心脏病患儿中，分别于心尖四腔及二腔观采集二尖瓣血流的彩色M型图像。应用自行设计的计算机辅助测量系统(CAMS)测量二尖瓣血流传播速度。分别在四腔及二腔观选取3种不同的感兴趣色彩测定血流传播速度(Vp)。所有患者均进行心导管检查，并将超声测得二尖瓣血流传播速度与心导管参数进行比较。结果所有患者中．由心尖四腔及二腔观图像所获得的Vp之间差异无显著性意义。在33例先天性心脏病患者中．不同切面及不同感兴趣色彩所测得的Vp之间差异无显著性意义。不同切面与不同感兴趣色彩所测得的Vp均与左心室舒缓时间常数(τ)显著相关。当设定处理色彩代表较高的血流速度时。Vp与τ之间的相关性更好。结论CAMS系统可准确地估测二尖瓣血流传播速度以反映左心室舒张功能。切面观选择对血流传播速度的选择无显著影响．在检测中应选定代表较高血流速度的感兴趣色彩。     

Influence of Doppler sample volume location on the assessment of changes in mitral inflow velocity profiles

Previous studies that have validated Doppler indexes of mitral inflow have used pulsed wave sample volume locations either at the level of the mitral valve anulus or at the tips of the mitral valve leaflets. Although significant differences between absolute values for peak velocities and velocity time integrals at these sample volume locations have previously been reported, no information exists that has compared changes in inflow profiles after an intervention to improve left ventricular filling. To address this question, 13 patients with severe pulmonary hypertension (mean pulmonary artery pressure, 50 +/- 13 mm Hg) caused by chronic thromboembolic disease were studied with use of Doppler echocardiography immediately before and after surgical reduction of pulmonary hypertension (pulmonary vascular resistance decreased from 916 +/- 413 to 233 +/- 89 dynes.sec.cm5). This clinical model has been shown to have abnormal mitral inflow velocity profiles that improve markedly after surgery. Doppler measures of early and late peak velocities were significantly lower both before and after surgery when sampling at the mitral anulus compared with the leaflet tips, although late filling parameters and the deceleration of early flow velocity tended to differ little. With surgery, the significant increase in peak early velocity and the ratio of early to late velocity was present regardless of the sample volume location (peak E at leaflet tips, 47.1 +/- 16.0 to 68.9 +/- 15.4 [p less than 0.001], and at anulus, 40.7 +/- 11.3 to 56.2 +/- 14.6 cm/sec [p less than 0.001]; peak E/A at leaflet tips, 0.95 +/- 0.4 to 1.55 +/- 0.9, and at anulus, 0.78 +/- 0.3 to 1.32 +/- 0.7 [both p less than 0.02]).(ABSTRACT TRUNCATED AT 250 WORDS)     

Orthostatic hypotension and cerebral blood flow velocity in the rehabilitation of stroke patients

The objective of this study was to investigate the results of transcranial Doppler monitoring during tilt table tests in stroke patients with and without orthostatic hypotension. In stroke patients without orthostatic hypotension, the mean flow velocity was almost similar in both middle cerebral arteries and was stable during the test. In patients with orthostatic hypotension symptoms, a significant difference was found between the two hemispheres. Mean flow velocity in the damaged middle cerebral artery was lower in the supine position and stayed almost the same at 80 degrees standing. In the non-damaged middle cerebral artery, however, the mean flow velocity was much higher when supine and dropped in the standing position. These findings suggest that the appearance of orthostatic hypotension symptoms may be associated in post-stroke patients with decreased blood velocity in the damaged middle cerebral artery. Those patients are at a high risk of developing syncopal reactions and should be treated on the tilt table with caution, especially at the beginning of the rehabilitation.     

Systolic and diastolic changes in human coronary blood flow during Valsalva manoeuvre

Valsalva manoeuvre is reported to be sometimes successful for the relief of angina pectoris. The present study investigated how haemodynamic changes produced by Valsalva manoeuvre can interact to improve the relationship between cardiac work and coronary blood flow. Ten male subjects aged 53 ± 12 years (SD) were considered. Blood velocity in the internal mammary artery, previously anastomosed to the left descending coronary artery, was studied with Doppler technique. The subjects performed Valsalva manoeuvres by expiring into a tube connected to a mercury manometer, to develop a pressure of 40 mmHg. The arterial blood pressure curve was continuously monitored with a Finapres device from a finger of the left hand. During expiratory effort, an increase in heart rate and a decrease in arterial pulse pressure were followed by a more delayed and progressive increase in mean and diastolic pressures. Systolic blood velocity markedly decreased along with the reduction in pulse pressure and increase in heart rate. By contrast, diastolic and mean coronary blood velocities did not show any significant change. Since it is known that the Valsalva manoeuvre strongly reduces stroke volume and cardiac output, it is likely that a reduction in cardiac work also takes place. Since in diastole, i.e. when the myocardial wall is better perfused, coronary blood velocity did not show any significant reduction, it is likely that unchanged perfusion in the presence of reduced cardiac work is responsible for the relief from angina sometimes observed during Valsalva manoeuvre. It is also likely that the increase in heart rate prevents the diastolic and mean blood coronary velocity from decreasing during the expiratory strain, when an increased sympathetic discharge could cause vasoconstriction through the stimulation of the coronary α‐receptors.     

Pulmonary venous flow velocity: relation to hemodynamics, mitral flow velocity and left atrial volume, and ejection fraction.

Abnormal pulmonary venous flow velocity patterns are present in multiple cardiac disease states, but the determinants of pulmonary venous flow velocity have not been fully elucidated. To determine the relative importance of several proposed factors that could influence pulmonary venous flow, anatomic, hemodynamic, and Doppler mitral and pulmonary venous flow velocity data were compared in 50 consecutive patients undergoing cardiac catheterization for clinical reasons. Pulmonary venous diastolic flow velocity was most strongly related to left ventricular isovolumetric relaxation time (r = -0.59), left ventricular end-diastolic pressure (LVEDP, r = 0.50), left atrial minimum volume (r = 0.50), mitral deceleration time (r = -0.50), and early diastolic mitral flow velocity (r = 0.45). Pulmonary venous systolic flow velocity related best with left atrial minimum volume (r = -0.45) and left atrial ejection fraction (r = 0.44). Pulmonary venous systolic flow velocity integral also showed the strongest relation with left atrial minimum volume (r = -0.48). Relations between pulmonary venous flow velocity and velocity time integrals and other variables were sometimes significantly different, apparently caused in part to differences in heart rate. These results suggest that pulmonary venous diastolic flow velocity is influenced by the same factors that influence early left ventricular diastolic filling; pulmonary venous systolic flow velocity relates best to left atrial volume and atrial ejection fraction and does not relate to left ventricular ejection fraction. Future studies analyzing pulmonary venous flow velocity variables should include data on both peak velocities and velocity time integrals as well as left atrial size and function.     

Fetal heart rate and blood flow velocity variability in the presence of increased nuchal translucency: a preliminary study.

OBJECTIVE: To study the power spectrum distribution of heart rate and umbilical artery flow velocity variability in fetuses with increased nuchal translucency thickness (NT). METHODS: Doppler velocity waveforms were collected from long-lasting (>20 s) umbilical artery recordings in 18 fetuses with increased NT (>3 mm) and 18 normal controls matched for gestational age at 11-14 (median, 12) weeks. The NT group included 11 abnormal karyotypes: trisomy 18 (n = 3), 45,X (n = 4), trisomy 21 (n = 3) and a balanced translocation. Absolute heart rate as well as the coefficient of variation for both beat-to-beat heart rate variability and umbilical artery blood flow velocity variability were determined. The ratios of the integrated low-frequency components (0.05-0.2 Hz) and the integrated high-frequency ones (0.25-1.6 Hz; LH ratio) from normalized power spectrum distributions were established to reflect sympathovagal balance. RESULTS: The mean heart rate was not significantly different between the two groups. However, mean heart rate variability and time-averaged flow velocity variability were significantly increased in the NT group, while there was no significant difference in the LH ratios between the two groups. The mean umbilical artery pulsatility index was significantly higher in the NT group. CONCLUSION: The autonomic nervous system does not seem to play a role in the altered cardiovascular homeostasis in the presence of increased fetal NT.     

红细胞分布宽度、肾小球滤过率与慢性心力衰竭的相关性研究

目的 研究红细胞分布宽度(RDW)、肾小球滤过率(GFR)与慢性心力衰竭的相关性,并探讨其可能的机制和意义.方法 收集160例慢性心力衰竭患者的住院病历资料,根据纽约心脏病学会(NYHA)心功能分级分为:心功能Ⅱ级组(n=52),心功能Ⅲ级组(n=58),心功能Ⅳ级组(n=50).另选取40例同期住院的非慢性心力衰竭患者作为对照组,比较RDW、GFR、血红蛋白(Hb)、脑钠肽(BNP)、心脏超声相关参数、左心室质量(LVM)和左心室质量指数(LVMI)等在各组间的变化差异,分析RDW、GFR与慢性心力衰竭严重程度的相关性.结果 随着NYHA心功能分级的逐步增加,RDW水平呈逐渐升高趋势,GFR、Hb水平呈逐渐降低趋势,且各组间差异均有统计学意义:RDW(12.31±0.34)% vs (14.24±0.74)%、(15.11±0.74)%、(16.18±0.89)%,GFR(106.70±22.01) ml·min-1·1.73 m-2 vs (83.32±15.38) ml·min-1·1.73 m-2 、(69.63±13.20) ml·min-1·1.73 m-2 、(61.48±13.46) ml·min-1·1.73 m-2,Hb(145.15±9.09) g/L vs (137.65±11.13) g/L、(129.14±13.58) g/L、(117.84±14.86) g/L (均P＜0.01).经相关性分析,RDW和BNP、LVEDd、LVM、LVMI呈正相关(r=0.652、0.639、0.420、0.432,均P＜0.01),和LVEF呈负相关(r＝-0.733,P＜0.01);GFR和BNP、LVEDd、LVM、LVMI呈负相关(r＝-0.481、-0.377、-0.199、-0.333,P＜0.05或＜0.01),和LVEF呈正相关(r＝0.456,P＜0.01);RDW和Hb、GFR呈负相关(r＝-0.815、-0.532,P＜0.01),Hb和GFR呈正相关(r＝0.659,P＜0.01).结论 RDW、GFR水平和慢性心力衰竭严重程度之间存在显著的相关性:慢性心力衰竭患者的心功能越差,左心室重构程度越重,则RDW水平越高,GFR水平越低.RDW和GFR可作为评估慢性心力衰竭严重程度的有力指标.     

彩色血流传播速度对二尖瓣置换术后左心室舒张功能的定量评估

目的 探讨彩色M型多普勒(CMM)评价二尖瓣置换术(MVR)后患者左室舒张功能的临床价值.方法 52例接受MVR术后3个月以上患者为病例组,另选取年龄、性别相匹配的30例正常人为对照组.测量左房室腔大小、机械瓣口流速、射血分数(EF)等常规超声心动图指标;应用CMM测量舒张期左室内彩色血流传播速度(Vp),计算二尖瓣位机械瓣口血流速度(E)与Vp比值(E/Vp);应用组织多普勒测量二尖瓣环舒张期峰值速度(Em),计算均值Em'和E/Em'.结果 ①MVR组Vp、Em较对照组明显减低,E/Vp、E/Em'较对照组明显增高,差异有统计学意义(P<0.001).E/Vp与E/Em'相关性良好,r=0.86,P <0.01;②Vp受左窜收缩功能和心律的影响,当EF≤50%或者心房颤动时,Vp减低更明显(P<0.01),而E/Vp受EF及心房颤动的影响较小(P>0.05);③绘制ROC曲线,以E/Vp≥2.00为最佳截断值,预测E/Em'≥15的敏感性为92.31%,特异性为83.65%,曲线下面积0.954.结论 CMM可用于评价MVR术后左室舒张功能;E/Vp与E/Em具有良好的一致性,可作为评价MVR术后左室舒张功能的有效指标.     

Role of preload and inotropy in stroke volume regulation at constant heart rate.

The relationship between preload and inotropy on left ventricular function was studied in anaesthetized open-chest dogs, by measuring left ventricular dimensions and stroke volume before and during saline infusion at different levels of inotropy. Left ventricular dimensions were continuously estimated by recording myocardial chord length (MCL) in the anterior wall of the left ventricle by ultrasonic technique. The effects of isoproterenol, a stimulator of adrenergic beta-receptors (high inotropy), and propranolol, an inhibitor of adrenergic beta-receptors (low inotropy), were examined during right atrial pacing at constant heart rate averaging 161 +/- 5 beats/min. Stroke volume was varied within the range 9.0 +/- 1.7 ml to 28.6 +/- 3.2 ml by increasing inotropy and preload. To increase preload, saline was infused intravenously until end-diastolic MCL increased by about 10% and left ventricular end-diastolic pressure was higher than 10 mmHg. At constant heart rate and blood volume, both before and during saline infusion, end-diastolic MCL was not influenced by isoproterenol or propranolol administration. End-systolic MCL was reduced by raising inotropy. The difference between end-diastolic and end-systolic MCL, the systolic myocardial shortening (MS), increased during saline infusion; the relative increase in MS was the same at high and low inotropy. On average, MS was more than 50% longer at high than at low inotropy, both before and after saline infusion. Thus, left ventricular end-diastolic volume is increased by saline infusion and end-systolic volume is reduced by increasing inotropy. Preload and inotropy exert independent effects on stroke volume.     

三维超声体积自动测量技术评估肺血减少型先天性心脏病胎儿肺体积变化

目的 采用三维超声计算机辅助虚拟脏器分析（VOCAL）技术观察肺血减少型先天性心脏病（CHD-DPBF）对胎儿肺体积发育的影响。方法 收集41胎法洛四联症（TOF）胎儿（TOF组）和110胎正常胎儿（对照组），以二维超声估测胎儿孕周、体质量及心胸比（CTR），以三维超声VOCAL技术测量胎儿肺体积，计算超声肺重比（肺体积与体质量的比值）和肺体积与孕周比值，比较2组间的差异；评估胎儿肺体积与孕周的相关性。结果 TOF组胎儿孕周、估算体质量和肺体积与对照组比较差异无统计学意义（P均>0.05），TOF组胎儿CTR大于对照组（P<0.001），胎儿肺体积与孕周比值及超声肺重比小于对照组（P均<0.05）。TOF组及对照组胎儿肺体积与孕周均呈正相关（r=0.611、0.547，P均<0.001）。结论 CHD-DPBF胎儿超声肺重比及肺体积与孕周比值均低于正常胎儿，提示CHD-DPBF胎儿肺脏发育受到一定程度不良影响。     

Unique features of early diastolic mitral annulus velocity in constrictive pericarditis.

BACKGROUND: In most primary myocardial diseases, early diastolic mitral annulus velocity (E') decreases with disease progression. To our knowledge, constrictive pericarditis (CP) is the only condition without this phenomenon. OBJECTIVE: This study was performed to evaluate the diagnostic and pathophysiologic role of mitral annulus velocity in patients with CP. METHODS: In all, 17 patients with CP (9 men; mean age 46.5 +/- 14.3 years), 8 patients with cardiac tamponade (Tamp) (2 men; mean age 44.5 +/- 15.0 years), and age- and sex-matched control subjects for CP and Tamp were recruited for the study. Early mitral inflow velocity and E' were obtained while simultaneously recording respiration. In 8 patients with CP and in all patients with Tamp, these measurements were repeated after the relief of constrictive physiology or after pericardiocentesis. RESULTS: In patients with CP, E' was significantly higher than it was for control subjects (12.9 +/- 3.0 cm/s vs 9.8 +/- 2.4 cm/s, P <.01). An E' of 2 cm/s higher than the predicted normal E' could differentiate patients with CP from control subjects with a sensitivity of 76% and specificity of 82%. In 12 of 17 patients (71%), inspiratory E' was higher than expiratory E'-the opposite of mitral inflow variation. In 8 patients, E' decreased significantly after the relief of constrictive physiology (13.8 +/- 2.5 cm/s vs 9.3 +/- 3.1 cm/s, P <.05). In contrast, E' in the Tamp group was significantly lower than in the control group (6.8 +/- 1.6 cm/s vs 10.2 +/- 2.5 cm/s, P <.01), did not show significant respiratory variation, and increased significantly after pericardiocentesis (6.8 +/- 1.6 cm/s vs 9.5 +/- 3.0 cm/s, P <.05). CONCLUSION: E' is exaggerated in CP, which is helpful for diagnosis. The opposite phenomenon was noted in Tamp, a dissimilarity that might contribute to different hemodynamics.     

正常青年人汉语认知活动与脑血流速度变化的相关性研究

目的:探讨汉语认知任务的完成对脑血流速度的影响。方法:在进行汉语词语联想、句子重建、近意词辨别认知任务时及其先前的休息期,对45个正常的志愿者(右利手)用经颅超声多普勒监测其双侧大脑中动脉血流速度的变化。结果:完成认知任务时与休息时期相比,所有认知任务的完成均诱导出双侧大脑中动脉血流速度的显著增加(P<0.01):词语联想任务左侧相对增加14.2±4.7,右侧8.5±2.8,句子重建左侧相对增加13.8±3.2,右侧8.6±2.2,近意词辨别左侧相对增加13.0±6.4,右侧7.3±3.1;并显现出显著的左侧半球偏侧化。性别对部分认知活动诱导的脑血流速度变化产生影响,但男女性别间偏侧化倾向无显著差异。结论:词语联想、句子重建、近意词辨别任务可诱导脑血流速度的左侧偏侧化。     

Impact of congenital heart disease on cerebrovascular blood flow dynamics in the fetus.

OBJECTIVES: Neurological abnormalities are present in some children after repair of congenital heart disease (CHD). Recently, structural brain abnormalities have been identified in infants prior to cardiac surgery. By altering in utero blood flow patterns, the type of CHD may impact upon cerebrovascular flow dynamics prior to birth. We sought to determine whether left- and right-sided obstructive congenital heart lesions modify cerebrovascular flow dynamics in the fetus. METHODS: Pulsed Doppler was used to measure blood flow velocities in the umbilical (UA) and middle cerebral (MCA) arteries in 172 fetuses from 20 to 39 weeks' gestational age referred for fetal echocardiography. Pulsatility index (PI), an indicator of downstream vascular resistance, was determined by (peak systolic velocity--end-diastolic velocity)/mean velocity. RESULTS: Fetuses with hypoplastic left heart syndrome (HLHS; n = 28) had decreased MCA-PI (P = 0.009) compared to normal fetuses (n = 114). Fetuses with right-sided obstructive lesions (RSOL; n = 17) had increased MCA-PI (P = 0.001) when compared to fetuses with HLHS. The UA-PI was elevated in fetuses with RSOLs (P = 0.045). CONCLUSIONS: Cerebrovascular resistance is lower than normal in fetuses with HLHS, a condition in which cerebral perfusion occurs retrograde via the ductus arteriosus. Fetuses with RSOL had significantly higher cerebrovascular resistance compared to fetuses with HLHS. The type of CHD impacts upon fetal cerebrovascular blood flow distribution and this may have implications for later development of neurological sequelae.     

Influence of body size and age on maximal diastolic velocity of mitral annulus motion.

BACKGROUND: Maximal long-axis relaxation velocity (RV(m)), measured from the mitral annulus motion (MAM), has recently been suggested as an index of left ventricular (LV) diastolic function. M-mode recording and pulsed tissue Doppler have been used. Regarding the M-mode method, reference values have not been presented previously. In the current study, therefore, the influence on RV(m) of such variables as age, body size, heart rate, and blood pressure was investigated to obtain adequate reference values. METHODS AND RESULTS: Fifty-seven healthy subjects were included in the study. RV(m) was recorded by M-mode echocardiography from apical 4- and 2-chamber views from 4 sites of the mitral annulus. Multiple regression analysis showed that heart rate ought to be taken into account when reference values are calculated for children and adolescents, and age must be considered in adults. For reference values in children and adolescents, the following equation is suggested: RV(m) = 171 - 0.54 x heart rate (SEE = 18.7). In adults over 18 years, the suggested equation is RV(m) = 163 - 1.29 x age (SEE = 8.4.)