Myocardial mechanics: understanding and applying three-dimensional speckle tracking echocardiography in clinical practice

Speckle tracking echocardiography (STE) is an emerging tool to characterize and quantify myocardial segmental and rotational mechanics. This literature review is aimed at clinical and academic cardiologists to provide: (1) a conceptual framework of STE to initiate understanding of myocardial mechanics; (2) evidence that three-dimensional (3D) STE overcomes the problems of time-consuming data acquisition and postprocessing seen with two-dimensional STE; and (3) illustrative clinical cases with analysis of myocardial mechanics via 3D STE to show the incremental value of strain in clinical decision making.     

Evaluation of myocardial deformation in patients with sickle cell disease and preserved ejection fraction using three-dimensional speckle tracking echocardiography

Background: Sickle cell disease (SCD) is a hemoglobinopathy that affects one in 500 African Americans. Although it is well established that patients with SCD have left ventricular (LV) diastolic dysfunction, it is not clear whether they have subtle LV systolic dysfunction despite preserved ejection fraction (EF). We used three-dimensional speckle tracking echocardiography (3DSTE) to assess changes in both systolic and diastolic LV function in SCD. Methods: Transthoracic real time 3D images were obtained (Philips iE33) in 56 subjects, including 28 stable outpatients with SCD (age 33 ± 7 years) and 28 normal controls (age 35 ± 9 years). 3DSTE was performed using prototype software (4DLV Analysis, TomTec) to obtain LV volume and deformation time curves, from which indices of systolic and diastolic LV function were calculated. Results: In SCD patients, 3DSTE-derived LV filling parameters were significantly different from normal controls, reflecting an increase in both rapid and atrial filling volumes and prolonged active relaxation, depicted by a decrease in filling volume fractions at fixed times and an increase in rapid filling duration. Global LV systolic function was not only preserved but increased compared to controls, as reflected by significantly increased global longitudinal strain. Importantly, twist angle and torsion as well as radial and circumferential components of 3D strain were similar in both groups. Conclusions: 3DSTE was able to confirm diastolic dysfunction, as expected in some patients with SCD. However, 3DSTE strain analysis did not reveal any changes in LV systolic function. These findings provide novel insight into the pathophysiology of the cardiovascular complications of SCD.     

Two-dimensional color Doppler echocardiography for left ventricular stroke volume assessment: a comparison study with three-dimensional echocardiography

Aim: Whether measurement of left ventricular outflow tract diameter (LVOTd) using color Doppler (CD) in order to more accurately define LVOTd is more accurate for determination of stroke volume (SV) than gray scale and compare it with direct measurement of LVOT area (a) using three‐dimensional echocardiography (3DE) for SV determination. Methods and Results: Twenty‐one volunteers were examined. LVOTa was calculated by two‐dimensional echocardiography (2DE) using the following formula: π× (d/2)², d = LVOT diameter by gray scale and CD, respectively. Planimetry of LVOTa was performed in parasternal long axis using 3DE. Eccentricity Index was calculated using the lateral and anterior‐posterior LVOTd. SV was obtained by four different methods: (1) 2D gray scale, (2) 2D color, (3) LVOTa × LVOT velocity time integral, and (4) SV by Simpson's biplane method. Gray scale LVOTd was significantly smaller compared to LVOTd obtained with CD (P < 0.05). Significant differences occurred between LVOTa gray scale and CD (3.29 ± 0.74 cm² vs 3.67 ± 0.70 cm², P < 0.05) and between LVOTa calculated by gray scale in comparison to 3DE planimetry; (3.29 ± 0.74 cm² vs 3.61 ± 0.89 cm², P = 0.011). Half of the subjects had at least 17% difference between the lateral and anterior‐posterior LVOTd. There were significant differences between SV by 2D gray scale and 2D CD (82.8 ± 17.1 mL vs 92.4 ± 16.8 mL, P < 0.05) and between 2D gray scale and 3DE planimetry (82.8 ± 17.1 mL vs 90.7 ± 19.8 mL, P = 0.025). Conclusion: Our study demonstrates LVOT being frequently elliptical. SV and LVOTa were found to be similar when comparing 2DE CD and 3DE planimetry and showed higher values in comparison to 2DE gray scale, which suggests 2DE CD to be an alternative approach for SV assessment.     

Real time three-dimensional stress echocardiography: a new approach for assessing diastolic function

Objective: To assess the feasibility of utilizing real time three‐dimensional echocardiography (RT3DE) for assessment of diastolic function during stress. Methods: Rest and stress volumes were acquired in 24 patients and parameters of diastolic function—peak ventricular filling rate (PFR) and time to peak filling rate (TPFR)—were calculated. Results: Calculation of diastolic parameters was feasible in all patients. Resting PFR correlated with end‐diastolic (EDV) and stroke volumes and inversely with TPFR (r = 0.53, 0.66, –0.5). With stress, PFR increased by 93% and TPFR decreased by 23% (P < 0.001). Stress PFR correlated with stress heart rate, EDV and stroke volume (r = 0.52, 0.50, 0.62) while TPFR correlated inversely with heart rate (r =–0.71). The change in PFR with stress correlated with the change in stroke volume (r = 0.42), while the change in TPFR correlated with the change in end‐systolic volume (ESV) (r = 0.43) and inversely with the change in diastolic blood pressure (r =–0.41). Rest and stress PFR and TPFR are independent of age, gender and blood pressure and the change in PFR is independent of stress heart rate or blood pressure. E/E′ correlated with stress TPFR (r = 0.72) and change in TPFR (r = 0.67) and inversely with change in PFR (r =–0.67). Conclusions: RT3DE can assess diastolic function during stress by detecting changes in PFR and TPFR, independent of gender, age, and blood pressure. The changes in these parameters with stress are influenced by baseline filling pressures. Larger studies are required to validate the clinical significance of these observations. (Echocardiography 2011;28:676‐683)     

二维斑点追踪技术在同年龄段尿毒症患者左房功能中的研究

目的 应用超声心动图评价尿毒症患者左房大小及功能,并探讨年龄对其影响.方法 选取金山医院肾内科2016年1月-2018年6月期间常规透析治疗尿毒症患者174例及性别、年龄相匹配的正常人55例为研究对象,按年龄＜45岁、45～64岁及≥65岁分成青年组、中年组和老年组.超声心动图测量左房内径、容积及左房射血分数(LAEF...     

Assessment of Interventricular Dyssynchrony by Real Time Three‐Dimensional Echocardiography: An In Vitro Study in a Porcine Model

Background: Loss of synchronous contraction between or within the right and left ventricle (RV, LV) leads to adverse ventricular function. We used real time three‐dimensional echocardiography (RT3DE) for evaluation of severity of interventricular dyssynchrony and function in a porcine heart model. Methods: Six fresh in vitro porcine hearts were used to create a controlled model of LV and RV dyssynchrony using two sets of pulsatile pumps. Synchronized and dyssynchronized pump settings were used with two different dyssynchronized settings: LV filled first and RV filled first. Results: There was good correlation between actual measurement and RT3DE for interventricular time difference (r = 0.95, P < 0.0001) and stroke volume (SV) for LV and RV (0.89, 0.85; P < 0.0001, respectively). RT3DE data showed a small but significant underestimation for actual volume (P < 0.05). The intra‐ and interobserver variabilities are 2.9 ± 1.5% and 3.1 ± 5.4% for LV and RV SVs, and 1.7 ± 2.4% and 2.2 ± 3.2% for time differences by RT3DE. There was significant difference in RV SV between synchrony and dyssynchrony when the RV filled first (P < 0.05), but not in other groups. The same pattern was found in RT3DE derived SVs (synchrony versus dyssynchrony with RV filled first, P < 0.05). Conclusions: There is no compromise in LV SV during interventricular dyssynchrony; but RV SV was significantly diminished when the RV filled first. RT3DE is a feasible, robust and reproducible method to identify interventricular dyssynchrony and to evaluate ventricular SVs. (Echocardiography 2010;27:709‐715)     

Three-dimensional echocardiography in congenital heart disease

Complex intracardiac anatomy and spatial relationships are inherent to congenital heart defects (CHDs). Recognition of the limitations of two-dimensional echocardiography has stimulated clinical interest in three-dimensional imaging. The current review examines contemporary studies in the following areas where three-dimensional echocardiography has provided additive value in CHD: (1) visualization of morphology, (2) quantitation of chamber sizes and ventricular function, and (3) image-guided interventions.     

Pulmonary venous flow as assessed by Doppler echocardiography: potential clinical applications

During the past few years Doppler assessment of pulmonary venous flow has gained increasing interest. The growing experience with the use of transesophageal echocardiography, the approach that nearly always yields registrations adequate for quantitative analysis, has markedly contributed in this respect. The Doppler-derived pulmonary venous flow pattern can be regarded as a measure of left atrial inflow and it augments the clinical significance of Doppler transmitral flow in the evaluation of diastolic left ventricular function. This article summarizes physiological background, possible applications, and limitations of Doppler echocardiography of pulmonary venous flow in clinical cardiology.     

急性心肌梗死患者室壁运动及心功能损害与发病-超声检查时间的关系

目的 探索急性心肌梗死患者室壁运动及心功能损害与发病-超声检查时间的关系.方法 收集初发急性心肌梗死患者219例,均已排除陈旧性心肌梗死、早期心肌再梗死、严重的瓣膜性心脏病、先天性心脏病、心肌病等影响室壁运动及心功能的疾病.所有患者均在予冠状动脉介入干预前行经胸超声心动图检查,采用二维超声等方法测量或（和）计算左心室舒张末期内径（left ventricular diameters in diastasis,LVDd）、收缩末期内径（left ventricular diameters in systole,LVDs）、左心室射血分数（left ventricular ejection fraction,LVEF）、室壁运动计分指数（wall motion index,WMI）及运动正常节段（fragments with normal wall motion,FM）百分比等参数,并精确记录发病-超声检查时间.结果 WMI、LVDd、LVDs、LVEF、FM百分比与发病-超声检查时间的相关关系均有统计学意义（P＜0.05）,相关系数分别为0.167,0.235,0.258,-0.196,-0.144.在WMI的多重线性回归分析结果显示,变量FM百分比、LVEF、左回旋支和（或）右冠状动脉进入方程（R2=0.878,justed R2=0.876）,偏回归系数分别为-1.103,-0.030,-0.001.结论 对于未予冠状动脉介入干预的急性心肌梗死患者,其室壁运动及心功能均随发病-超声检查时间的增加而减弱.     

Segmental Contribution to Left Ventricular Systolic Function at Rest and Stress: A Quantitative Real Time Three‐Dimensional Echocardiographic Study

Objective: To assess the relative contribution of each myocardial segment to global systolic function during stress using real time three‐dimensional echocardiography (RT3DE). Background: During stress, global augmentation in contractility results in an increased stroke volume. The relative contribution of each myocardial segment to these volumetric changes is unknown. Methods: Full volume was acquired using RT3DE at rest and following peak exercise in 22 patients who had no ischemia and no systolic dyssynchrony on two‐dimensional (2D) stress echocardiography. The following were calculated at rest and peak stress: end‐diastolic volume (EDV), end‐systolic volume (ESV), stroke volume (SV), ejection fraction (EF), relative SV, and relative EF. Results: With stress, an increase in global EDV from 90.8 to 101.1 ml (P < 0.001), SV from 59 to 78.4 ml (P = 0.01), and EF from 65.6 to 78.4% (P = 0.001) was observed. ESV decreased from 31.8 to 22.7 ml (P < 0.001). Segmental analysis revealed significantly higher SV, relative SV, and relative EF for the basal anterior, basal anterolateral, and basal inferolateral segments compared with the apical septum and apical inferior segments at both rest and stress (P < 0.001). The SV, relative SV, and relative EF increased significantly from apex to mid to base at both rest and stress (P < 0.001). Conclusions: The relative volumetric contribution of each myocardial segment to global left ventricular systolic function at rest and stress is not uniform. The basal segments contribute more than the mid and apical segments. Specifically, the basal anterior, basal anterolateral, and basal inferolateral segments contribute the most to augmentation of left ventricular systolic function with exercise. (ECHOCARDIOGRAPHY 2010;27:167‐173)