Assessment of Coronary Flow Velocity Reserve by Noninvasive Transthoracic Doppler Echocardiography in Patients with Angiographically Normal Coronary Arteries

Summary： The measurement of coronary flow velocity reserve （CFVR） by transthoracic Doppler echocardiography （TTDE） with invasive intracoronary Doppler flow wire technique （ICD） was validated and the pathological factors which influence CFVR in patients with angiographically normal coronary arteries were analyzed. CFVR was determined successfully in left anterior descending artery （LAD） in 37 of 40 patients with angiographically normal coronary arteries （men 22, women 15, age 20-75 years, mean age 54±12 years）. Coronary flow velocity was measured in the distal LAD by TTDE with contrast enhancement at baseline and during intravenous adenosine infusion of 110 μg/ kg per min within 48 h after ICD technique. Average peak velocity at baseline （APVb）, average peak velocity during hyperemia （APVh） and CFVR determined from TTDE were correlated closely with those from ICD measurements （APVb： y= 0. 64x＋ 5. 04, r=0. 86, P〈0. 001; APVh： y=0. 63x＋14. 36, r=0.82, P〈0.001; CFVR： y=0.65xq-0.92, r=0.88, P〈0.001）. For CFVR measurements, the mean differences between TTDE and ICD methods were 0. 12±0.39. CFVR in patients with history of hypertension was significantly lower than that in patients without history of hypertension （P〈0.05）. Intravascular ultrasound （IVUS） was performed in 34 patients. Plaque formation was found in LAD by IVUS in 17 （50%） patients. No significant difference in CFVR was found between the patients without plaque formation （3. 11±0. 49） and those with plaque formation （2. 76±0.53, P=0. 056）. It is suggested that TTDE with contrast enhancement provides reliable measurement of APV and CFVR in the distal I.AD. The early stage of atherosclerosis could be detected by IVUS, which may be normal in angiography. CFVR is impaired in patients with history of hypertension compared with that in patients without history of hypertension.

Non-invasive Assessment of Coronary Flow Velocity Reserve: A New Method Using Transthoracic Doppler Echocardiography

Summary: Transthoracic Doppler echocardiography (TTDE) allows noninvasive flow measurement in the distal left anterior descending artery (LAD). The feasibility of detecting coronary flow by contrast-enhanced TTDE with second harmonic technique was assessed, the coronary flow velocity reserve (CFVR) was evaluated in comparison to intracoronary Doppler flow (ICD) analysis and the CFVR after PTCA in LAD was investigated. In 77 (96 %) of 80 patients, CFVR was successfully determined with intravenous adenosine infusion. Doppler signal quality was evaluated in the first 46 patients by use of intravenous Levovist infusion and second harmonic technique. The Doppler flow was not visible in 1 patient only. CFVR determined from TTDE (2.77±0.65) was correlated closely with those from ICD (2.88±0.78) measurements (y=0.73x+0.67, r=0.87, P<0.001). In conclusion, TTDE is a feasible method and provides reliable data on CFVR which can be used for follow-up after PTCA.

Value of Acceleration Flow in the Left Anterior Descending Coronary Artery for the Detection of Coronary Artery Stenosis by Transthoracic Coronary Color Doppler Echocardiography

Summary： Whether the localized flow acceleration occurs in the resting stenotie left anterior descending coronary artery was explored and its value for detection of coronary stenosis estimated. Blood flow in the left anterior descending coronary arteries in 45 patients was detected by transthoratio color Doppler echocardiograph and multipoint pulse Doppler spectrums were recorded in the same segment. The ratio of the maximal peak diastolic velocity to the minimal peak diastolic velocity was calculated. The ratio ≥1.5 was the cutoff value for the presence of localized acceleration flow. There were 23 patients with localized acceleration flow examined by eehoeardiography. Twenty of them were found to have luminal diameter stenosis （60%-98%） in the left anterior descending coronary arteries by coronary angiography and 3 patients were normal. There were 22 patients without localized acceleration flow examined by eehoeardiography. Eighteen of them had no or %60 stenosis. Four patients had serious stenosis （≥95%） or occluded segments in the left anterior descending coronary arteries on coronary angiography. The ratio of the maximal peak diastolic velocity to the minimal peak diastolic velocity was significantly higher in patients with left anterior descending coronary artery stenosis than that in those without stenosis （1.9±0.3 vs 1.3±0.2, P〈0.01） and it correlated significantly with left anterior descending coronary artery stenosis （r=0.77, P〈0.01）. The specificity by using the ratio≥1. 5 for stenosis detection was 85.7% （18/ 21）, and the sensitivity was 83.3% （20/24）. This study demonstrated that local blood flow velocity was increased in the resting stenotie left anterior descending coronary artery. Transthoraeie color Doppler eehoeardiography is a reliable noninvasive method to detect localized acceleration flow in the left anterior descending coronary artery stenosis and it is useful in the noninvasive diagnosis of stenosis in the left anterior descending coronary artery.

STUDY OF PULSED DOPPLER SIGNAL PROCESSING AND VELOCITY TRACKING TECHNIQUE

This paper describes a signal processing system in a Pulsed Doppler (PD) radar. It mainly consists of a velocity tracking loop and a digital signal processing auxiliary channel. With many signal processing techniques, the system successfully solves the signal detection and tracking at low SNR and the interference identification and rejection. The idea of system design is introduced in detail. Finally, some simulation and experimental results are presented.

Pulsed Doppler Tissue Imaging for Assessment of Left Ventricular Systolic and Diastolic Synchronicity in Normal Subjects

Objectives To quantitatively analyze the longitudinal myocardial systolic and diastolic velocities and time intervals of the left ventricle in normal subjects, and to explore the value of pulsed Doppler tissue imaging （DTI） for the assessment of left ventricular systolic and diastolic synchronicity. Methods Twenty and six healthy subjects were studied by pulsed DTI. The septal and lateral, anterior and inferior walls of the left ventricle were displayed respectively, and basal and middle segments of each wall were selected for myocardial motion spectrum sampling. DTI parameters were： peak systolic myocardial velocity （s）, regional pre-ejection period （PEP）, time to the peak of s wave （Ts）, regional ejection time （ET） ; peak early diastolic velocity （e）, peak late diastolic velocity （a）, e/a ratio, time to the beginning of e wave （QE）, time to the peak of e wave （Te） and regional isovolumic relaxation time （IVRT）. Results The e and e/a were significantly different among basal segments, and s and e/a were significantly different among middle segments, with the highest value in lateral segments and the lowest value in septal segments. The s, e and a were all significantly higher in basal segments than middle segments. None of the systolic time intervals （PEP, Ts and ET） and diastolic time intervals （QE, Te and IVRT） were significantly different among basal segments and middle segments, neither were they when basal segment was compared with middle segment. Conclusions In normal subjects, the longitudinal myocardial systolic and diastolic velocities of the left ventricle are not homogeneous, but the contraction and relaxation are highly synchronized. Pulsed DTI can be used to quantitatively analyze the systolic and diastolic synchronicity of the heart.

Prevalence of Atrial Fibrillation in Systolic Heart Failure, Pulsed and Tissue Doppler Echocardiographic Abnormalities

Background: Heart failure (HF) is a common clinical syndrome mostly due to the impaired ability of the Left Ventricle (LV) to eject blood with reduced cardiac output. Heart failure is called systolic (SHF) if left ventricle ejection fraction on echo-cardiogram is low (LVEF of ≤50%). Aim: To assess the echocardiographic characteristics of patients with SHF with Atrial Fibrillation (AF) and compare with those with Sinus Rhythm (SR) on 12 leads ECG. Furthermore, to evaluate the clinical and biochemical markers for the prediction of AF in SHF. Method: Over two years duration, each patient diagnosed with SHF was enrolled in the study (n = 354) based on admission code. AF or sinus rhythm on 12 leads ECG was documented on each patient. Multiple logistic regression analysis was applied to assess the risk ratio of different clinical and Doppler derived variables for the development of AF in SHF. Results: Out of the total hospital medical admissions of 14,674 patients, there were 354 patients with diagnosis of SHF, a prevalence of 2.4%. The incidence of AF on ECG was 109 (31%) patients in the whole study population and 245 (69%) in SR. M Mode echocardiogram in patients with SHF and AF compared with those in SR showed significant dilation of LV cavity in systole with LVESD of 5.72 ± 0.63 vs. 5.23 ± 0.76 cm, P < 0.001 and in Diastole LVEDD of 6.83 ± 0.51 vs. 6.58 ± 0.63 cm, P < 0.001. Pulsed Doppler echocardiogram showed a severe restrictive-pattern with shorter Decellration Time (DT) of 163.73 ± 7.42 vs. 214.9 ± 31.81msec, P < 0.001 and higher Pulse to Tissue Doppler ratio of E/Em of 14.26 ± 1.34 vs. 9.99 ± 1.27, P , and the serum level of Brain Natriuretic Peptide (BNP) hormone of 723.72 ± 13.45 vs. 686.98 ± 72.57 pg/ml, P < 0.001. The predictive risks (odd ratio) of different clinical variables for the development of AF in SHF were positive for high BNP > 500 pg/ml of 2.8, history of hypertension of 1.8, history of DM of 1.7, BMI > 28 of 1.4, LV hypertrophy on ECG of 1.3. Conclusions: The prevalence of Systolic Heart Failure in the study population was 2.4%. The prevalence of AF in the study population was 31%. The best predictors of AF in SHF were high BNP > 500 pg/ml, history of hypertension, Diabete Mellitus and LV Hypertrophy on ECG.

Speckle tracking echocardiography:A new approach to myocardial function

Echocardiography is the most common diagnostic method for assessing cardiac function but some limitations affect this technique.Until now,visual assessment of wall motion and thickening has allowed only a subjective evaluation of myocardial function and requires long-term training.Recently,new echocardiographic techniques have been introduced to evaluate myocardial mechanics.Tissue Doppler imaging(TDI)technique is limited by angle-dependency such that only deformation along the ultrasound beam can be derived from velocities,while myocardium deforms simultaneously in three dimensions.Speckle tracking echocardiography (STE)is a more recent technique that provides a global approach to left ventricular myocardial mechanics,giving information about the three spatial dimensions of cardiac deformation.In this editorial,we describe the physical and pathophysiological concepts of STE,discussing the differences compared to TDI and underlining the pitfalls of this new technique.

Role of 2-dimensional Doppler echo-cardiography in screening portopulmonary hypertension in portal hypertension patients

BACKGROUND: Portopulmonary hypertension (PPH) is difficult to recognize in the early and middle stages because it is frequently asymptomatic. As right ventricular function is impaired in patients with moderate and severe PPH, any dramatic hemodynamic changes in liver transplantation or other procedures may result in death from pulmonary and cardiac events. In this study, we investigated the prevalence of PPH in patients with portal hypertension (PHT) mainly caused by hepatitis B virus, and evaluated the effect of 2-dimensional Doppler echocardiography (2D-ECHO) in screening for PPH. METHODS: One hundred and five PHT patients received transthoracic 2D-ECHO preoperatively, systolic pulmonary arterial pressure (SPAP, normal range <30 mmHg) and pulmonary acceleration time (PAT, normal range >= 120 msec) were measured to screen for PPH (positive result: SPAP >= 30 mmHg and/or PAT <100 msec). Subsequently, pulmonary hemodynamic parameters were measured by right heart catheterization (RHC) for definitive diagnosis of PPH. The results of the two methods were compared to assess the screening effect of 2D-ECHO. RESULTS: The prevalence of PPH in this study was 3.8% (4/105). About 90% (95/105) of patients had a detectable tricuspid regurgitation by 2D-ECHO and the mean SPAP was 27.7 +/- 5.9 mmHg. Twenty-two of these 95 patients had an SPAP >30 mmHg. The mean PAT of all patients was 140 23 msec and 5 were <100 msec. Twenty-two patients were screened out by 2D-ECHO and 4 were diagnosed by RHC. A positive significant correlation (r=0.55, P<0.01) was found between SPAP measured by 2D-ECHO and mean pulmonary artery pressure (MPAP) measured by RHC, and a weak but significant negative correlation (r=-0.27, P=0.005) existed between PAT and pulmonary vascular resistance (PVR). The sensitivity, specificity, agreement rate, positive predictive value and negative predictive value of the screening test were 100%, 82%, 83%, 18% and 100%, respectively. CONCLUSIONS: The prevalence of PPH in this study is lower than in Western countries. As a screening test, 2D-ECHO has very high sensitivity and negative predictive value. A negative test result can directly be used to exclude PPH, while a positive result should be confirmed by RHC.

Can transthoracic Doppler echocardiography be used to detect coronary slow flow phenomenon？

Background Coronary slow flow phenomenon （CSFP） is an important, angiographic clinical entity but is lacking non-invasive detecting techniques. This study aimed to elucidate the value of transthoracic Doppler echocardiography （TTDE） in the diagnosis and monitoring of coronary slow flow in left anterior descending （LAD） coronary artery.Methods We consecutively enrolled 27 patients with CSFP in LAD detected by coronary arteriography from August 2009 to April 2010. Thirty-eight patients with angiographically normal coronary flow served as control. Corrected thrombolysis in myocardial infarction （TIMI） frame count （CTFC） was used to document coronary flow velocities. All subjects underwent TTDE within 24 hours after coronary angiography. LAD flow was detected and the coronary diastolic peak velocities （DPV） and diastolic mean velocities （DMV） were calculated.Results Sixty of 65 （92.3%） subjects successfully underwent TTDE. Baseline clinical characteristics were similar between the two groups. Coronary DPV and DMV of LAD were significantly lower in the CSFP group than in the control group （（0.228±0.029） m/s vs. （0.302±0.065） m/s, P=0.000; （0.176±0.028） m/s vs. （0.226±0.052） m/s, P=0.000,respectively）. There was a high inverse correlation between CTFC and coronary DPV and DMV （r=-0.727, P=0.000;r=-0.671, P=0.000, respectively）. Receiver operating characteristic （ROC） curve showed that the area under the curve （AUC） was less than one half for coronary DPV （AUC=0.104） and DMV （AUC=0.204）, respectively.Conclusions In patients with CSFP, there is a high inverse correlation between CTFC and coronary diastolic flow velocities in the LAD coronary artery, as measured by TTDE. The value of TTDE in the monitoring and evaluation of coronary flow in patients with CSFP deserves further investigation.

Comparison between Doppler echocardiography and hot-film anemometry in measuring the turbulent shear stress downstream of artificial mitral valves： a methodological study

Background Turbulent shear stress （TSS） plays an important role in the research of fluid dynamics of heart valves. This study aimed to perform a quantitative study of TSS downstream of porcine artificial mitral valves in order to verify the correlation of hot-film anemometry （HFA） and Doppler echocardiography combined with computer-aided image analysis for the detection of TSS. Methods A porcine model of mitral valve replacement was established. HFA and Doppler ultrasound techniques were used to directly and indirectly measure TSS-relevant parameters of the artificial mitral valve following different mitral valve replacements： different approaches were used to reserve the subvalvular apparatus of the mitral valve. A correlation analysis was then carried out. Results There was a significant correlation between the HFA and Doppler ultrasound combined with computer-aided image analysis of the TSS at the same time and at the same site. No significant difference was found in the TSS measured by the two methods. Conclusions Compared with HFA, Doppler echocardiography combined with computer-aided image analysis is a safe, non-invasive, and real-time method that enables accurate and quantitative detection of TSS downstream in vivo, objectively reflecting the flow field downstream of the artificial mitral valve. Doppler ultrasound combined with computer- aided image analysis can be employed for quantitatively evaluating the downstream hemodynamic performance of the mitral valve.

Real-time Three-Dimensional Color Doppler Flow Imaging： An Improved Technique for Quantitative Analysis of Aortic Regurgitation

The recently introduced real-time three-dimensional color Doppler flow imaging （RT-3D CDFI） technique provides a quick and accurate calculation of regurgitant jet volume （RJV） and fraction. In order to evaluate RT-3D CDFI in the noninvasive assessment of aortic RJV and regurgitant jet fraction （RJF） in patients with isolated aortic regurgitation, real-time three-dimensional echocardiographic studies were performed on 23 patients with isolated aortic regurgitation to obtain LV end-diastolic volumes （LVEDV）, end-systolic volumes （LVESV） and RJV, and then RJF could be calculated. The regurgitant volume （RV） and regurgitant fraction （RF） calculated by two-dimensional pulsed Doppler （2D-PD） method served as reference values. The results showed that aortic RJV measured by the RT-3D CDFI method showed a good correlation with the 2D-PD measurements （r= 0.93, Y=0.89X＋ 3.9, SEE= 8.6 mL, P〈0.001 ）; the mean （SD） difference between the two methods was - 1.5 （9.8） mL. % RJF estimated by the RT-3D CDFI method was also correlated well with the values obtained by the 2D-PD method （r=0.88, Y=0.71X＋ 14.8, SEE= 6.4 %, P〈0. 001）; the mean （SD） difference between the two methods was -1.2 （7.9） %. It was suggested that the newly developed RT-3D CDFI technique was feasible in the majority of patients. In patients with eccentric aortic regurgitation, this new modality provides additional information to that obtained from the two-dimensional examination, which overcomes the inherent limitations of two-dimensional echocardiography by depicting the full extent of the jet trajectory. In addition, the RT-3D CDFI method is quick and accurate in calculating RJV and RJF.

Clinical Evaluation of Color Doppler Ultrasound in Selecting the Optimal Treatment Modality for Infantile Hemangioma

Objective We investigated the efficacy and safety of 1064 nm Nd： YAG laser, intense pulsed light （IPL）, and lauromacrogol injection in the treatment of hemangioma, in order to evaluate the value of color Doppler ultrasound guidance in choosing the optimal treatment modality. Methods Infantile patients who were clinical diagnosed as hemangiomas were randomly divided into group A, who had color Doppler ultrasound examinations before the treatment, and group B who had the treatment without ultrasound evaluation. Patients in the group A were assigned into subgroups according to the depth of lesion by sonography： group A-1 for those who had a lesion depth 〈1.2 mm, and took intense pulsed light therapy; group A-2 for those who had a lesion depth ≥1.2mm and 〈 3 mm, and took long pulse 1064 nm Nd：YAG laser therapy; group A-3 for those who had a lesion depth ≥3mm and 〈5 mm, and were treated by IPL combined with long pulse 1064 nm Nd：YAG laser treatment; Group A-4 for those who had a lesion depth ≥5 mm, and took lauromacrogol injection therapy. Patients in the group B took long pulse 1064 nm Nd：YAG laser treatment without preoperative ultrasound evaluation. The efficacy and adverse reactions of the treatments between the groups were evaluated and compared statistically. Results Totally 113 patients with 128 skin lesions were enrolled in this study, 85 in the group A （mean age 6.8±7.9 months） and 28 in the group B （mean age 6.9±9.9 months）. The mean depth of hemangioma was 3.3±1.1 mm in the group A, ranging from 0.5-7.8 mm, with 0.8±0.4 mm, 2.2±0.4 mm, 4.2±0.6 mm and 6.2±0.7 mm in group A1, A2, A3 and A4, respectively. The cure rates and effective rates in the group A were significantly higher than those in the group B （cure rates： 64.5% vs 56.3%, U=3.378, P=0.045; effective rates： 89.5% vs 78.1%, U=4.163, P=0.041）. The adverse effect rates of the group A （vesicle 20.0%, pigmentation 46.9%, scarring 17.7%） were lower than those of the group B （vesicle 21.9%, pigmentation 60.4%, scarring 25.0%）. Incidences of pigmentation and scarring were statistically significantly different （U=3.884, P=0.034, and U=4.016, P=0.032 respectively） between the two groups. Conclusion With the guidance of color Doppler ultrasound, the efficacy and safety of long pulse 1064 nmNd：YAG laser, intense pulsed light, and lauromacrogol injection in the treatment of infantile hemangioma have better outcomes compared to laser treatment alone without preoperative ultrasound examination.

Assessment and impact of diastolic function by echocardiography in elderly patients

Doppler echocardiography is the gold standard for assessment of diastolic dysfunction, which is increasingly recognised as a cause of heart failure, especially in the elderly. Using a combination of Doppler echocardiography techniques, it is possible to identify grades of dia- stolic dysftmction, estimate left ventricular filling pressures and establish the chronicity of diastolic dysfunction. These physiologi- cally-derived measures have been widely validated against invasive measurements of left heart pressures and have been shown to be prog- nostically valuable in a wide range of clinical settings. This review explores the mechanisms, and approaches to the assessment of diastolic dysfunction in the elderly. The challenge for clinicians is to identify pathophysiological changes from those associated with normal ageing. When used in combination, and taking age into account, Doppler echocardiographic parameters are helpful in the assessment of dyspnoea in older patients and provide prognostic insights.

Evaluation of right-to-left shunt on contrast-enhanced transcranial Doppler in patent foramen ovale-related cryptogenic stroke: Research based on imaging

BACKGROUND Cardiogenic embolism caused by patent foramen ovale(PFO)is a common etiology of cryptogenic stroke(CS),particularly in young and middle-aged patients.Studies about right-to-left shunt(RLS)detection using contrast-enhanced transcranial Doppler(c-TCD)are numerous.According to the time phase and number of microbubbles detected on c-TCD,RLS can be classified and graded.We hypothesized that the characteristics of an infarction lesion on diffusion-weighted imaging differs when combining the type and grade of RLS on c-TCD in patients with PFO-related CS.AIM To explore the characteristics of infarction lesions on diffusion-weighted imaging when combining the RLS type and grade determined by c-TCD.METHODS We retrospectively evaluated CS patients from August 2015 to December 2019 at a tertiary hospital.In total,111 PFO-related CS patients were divided according to whether RLS was permanent(microbubbles detected both at resting state and after the Valsalva maneuver)or latent(microbubbles detected only after the Valsalva maneuver)on c-TCD.Each group was subdivided into small,mild and large RLS according to the grade of shunt on c-TCD.A normal control group was composed of 33 patients who suffered from simple dizziness.Intragroup and intergroup differences were analyzed in terms of clinical,laboratory and diffusion-weighted imaging lesion characteristics.The correlation between RLS grade evaluated by c-TCD and size of PFO determined by transesophageal echocardiography were also analyzed.RESULTS In 111 patients with PFO-related CS,68 had permanent RLS and 43 had latent RLS.Clinical characteristics and laboratory tests were not significantly different among the permanent RLS,latent RLS and normal control groups.The proportion of patients with multiple territory lesions in the permanent RLS group(50%)was larger than that in the latent RLS group(27.91%;P=0.021).Posterior circulation was more likely to be affected in the latent RLS group than in the permanent RLS group(30.23%vs 8.82%,P=0.004).Permanent-large and latent-large RLS were both more likely to be related to multiple(P_(trend)=0.017 and 0.009,respectively),small(P_(trend)=0.035 and 0.006,respectively)and cortical(P_(trend)=0.031 and 0.033,respectively)lesions.The grade of RLS evaluated by c-TCD was correlated to the size of PFO determined by transesophageal echocardiography(r=0.758,P<0.001).CONCLUSION Distribution of the infarct suggested the possible type of RLS.Multiple,small and cortical infarcts suggest large RLS induced by a large PFO.

Assessment of atrial electromechanical interval using echocardiography after catheter ablation in patients with persistent atrial fibrillation

We sought to investigate variation of atrial electromechanical interval after catheter ablation procedure in patients with persistent atrial fibrillation using pulse Doppler（PW） and pulse tissue Doppler imaging（PW-TDI）.A total of 25 consecutive in-patients with persistent atrial fibrillation,who restored sinus rhythm after ablation procedure,were recruited in our cardiac center.Echocardiography was performed on each patient at 2 hours,1 day,5 days,1 month and 3 months after the ablation therapy,and atrial electromechanical delay was measured simultaneously by PW and PW-TDI.There was no significant difference between PW and TDI in measuring atrial electromechanical delay.However,at postoperative 2 hours,peak A detection rates were mathematically but nonsignificantly greater by PWTDI than by PW.Second,there was a significant decreasing trend in atrial electromechanical interval from postoperative 2 hours to 3 months,but only postoperative 2-hour atrial electromechanical interval was significantly greater than atrial electromechanical interval at other time.Lastly,patients without postoperative 2-hour atrial electromechanical interval had a significantly longer duration of atrial fibrillation as compared to those with postoperative 2-hour atrial electromechanical interval,by the PW or by PW-TDI,respectively.In patients with persistent atrial fibrillation,atrial electromechanical interval may decrease significantly within the first 24 hours after ablation but remain consistent later,and was significantly related to patients＇ duration of atrial fibrillation.Atrial electromechanical interval,as a potential predicted factor,is recommended to be measured by either PW or TDI after24 hours,when patients had recovered sinus rhythm by radiofrequency ablation.

高血压病心功能不全Doppler超声图的表现及意义

目的 :研究高血压病心功能不全 (HD)的 Doppler超声表现形式及临床意义。方法 :采用 2 5 0 0型多功能超声心动图对 78例高血压病 HD患者进行检测。结果 :轻度 HD组 :以 E/ A (二尖瓣舒张早期最大流速 /舒张晚期最大流速 ) <1,S/ D (肺静脉收缩期最大流速 /舒张期最大流速 ) >1为多 ,占 74.3%;中度 HD组 :以 1<E/ A<2 ,S/D<1为多 ,占 70 .8%;重度 HD组 :以 E/ A≥ 2 ,S/ D<1为多 ,占 80 %。单纯左室舒张功能障碍或与左室收缩功能障碍并存时 ,E/ A、 S/ D比值的变化规律与高血压病不同程度 NYHA心功能分级的相似。结论 :测定高血压病患者的 E/ A、S/ D对于评价其心功能、预后 ,指导治疗有重要意义。

Tissue Doppler,speckling tracking and four-dimensional echocardiographic assessment of right ventricular function in children with dilated cardiomyopathy

BACKGROUND Right ventricular(RV)function is frequently overlooked during dilated cardiomyopathy(DCM)evaluation.AIM To evaluate RV function in children with idiopathic DCM using relatively recent echocardiographic modalities.METHODS We prospectively studied the cardiac function in 50 children with idiopathic DCM and 50 healthy children as a control group,using four-dimensional echocardiography(4-DE),Tissue Doppler Imaging(TDI),and two-dimensional-speckles tracking echocardiography(2-D-STE).RV EF was measured by 4-DE.RESULTS The auto left(LV)ejection fractions(EF)measured by 2-D-STE were significantly lower in the patients'group than in the control.The sphericity index was also significantly lower in children with DCM than in the control.RV EF measured by 4-DE was significantly lower in the patient's group than the control.RV S wave,e´/a'ratio,myocardial performance index(MPI),and tricuspid annular plane systolic excursion(TAPSE)were significantly impaired in children with DCM than in control.Both LV and RV global longitudinal strains(GLS)were significantly reduced in children with DCM than in control.RVGLS was significantly associated with the duration since diagnosis,tricuspid annulus S wave,RV MPI,and TAPSE,but not with the age of the patients,RV EF,or e´/a'ratio.CONCLUSION There was impairment of the RV LGS and other systolic and diastolic parameters in children with DCM.STE and TDI can help to detect the early decline of RV function.

关于矩形脉冲类信号Doppler分辨的算法研究

对于由矩形脉冲构成的复杂信号来说 ,若按定义式计算其速度名义分辨参数或Doppler分辨常数往往比较复杂 ,特别是对于多周期信号更是如此。本文在求得信号模糊函数的基础上 ,抛开了分辨力的定义计算式 ,提出了从信号的模糊函数矩阵中 ,找出半功率点所在的行数 ,从而使这一问题得到解决 ,为快速估算信号的速度名义分辨参数提出了一种新的算法。另外 ,在对多周期“同步加白”信号Doppler分辨常数的计算中 ,充分利用单周期信号的计算结果 ,使对包络函数高次项的积分得到简化 ,避免了复杂、重复的运算 。

SEVERAL PROBLEMS IN DESIGNING DBS SYSTEMS FOR AIRBORNE PULSE DOPPLER RADAR

ＳＥＶＥＲＡＬＰＲＯＢＬＥＭＳＩＮＤＥＳＩＧＮＩＮＧＤＢＳＳＹＳＴＥＭＳＦＯＲＡＩＲＢＯＲＮＥＰＵＬＳＥＤＯＰＰＬＥＲＲＡＤＡＲＹＡＮＧＪｉａｎｈａｎｇ（杨建航）（ＤｅｐａｒｔｍｅｎｔｏｆＡｅｒｏ－ＥｌｅｃｔｒｏｎｉｃＥｎｇｉｎｅｒｉｎｇ，ＡｉｒＦｏ...

THE CLINICAL VALUE OF COLOR DOPPLER FLOW CONVERGENCE IN THE QUANTIFICATION OF MITRAL REGURGITATION

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