Color-coded measures of myocardial velocity throughout the cardiac cycle by tissue Doppler imaging to quantify regional left ventricular function

Improved velocity-selective labeling pulses for myocardial ASL

PURPOSE

To develop and evaluate an improved velocity-selective (VS) labeling pulse for myocardial arterial spin labeling (ASL) perfusion imaging that addresses two limitations of current pulses: (1) spurious labeling of moving myocardium and (2) low labeling efficiency.

METHODS

The proposed myocardial VSASL labeling pulse is designed using a Fourier Transform based Velocity-Selective labeling pulse train. The pulse utilizes bipolar velocity-encoding gradients, a 9-tap velocity-encoding envelope, and double-refocusing pulses with Malcolm Levitt phase cycling. Amplitudes of the velocity-encoding envelope were optimized to minimize the labeling of myocardial velocities during stable diastole (±2-3 cm/s) and maximize the labeling of coronary velocities (10-130 cm/s during rest/stress or 10-70 cm/s during rest). Myocardial ASL experiments were performed in seven healthy subjects using the previously developed VS-ASL protocol by Jao et al with the two proposed VS pulses and original VS pulse. Myocardial ASL experiments were also performed using FAIR ASL. Myocardial perfusion and physiological noise (PN) were evaluated and compared.

RESULTS

Bloch simulations of the first and second proposed pulses show <2% labeling over ±3 cm/s and ±2 cm/s, respectively. Bloch simulations also show the mean labeling efficiency of arterial blood is 1.23 over the relevant coronary arterial ranges. In-vivo VSASL experiments show the proposed pulses provided comparable measurements to FAIR ASL and reduced TSNR in 5 of 7 subjects compared to the original VS pulse.

CONCLUSION

We demonstrate an improved VS labeling pulse specifically for myocardial ASL perfusion imaging to reduce spurious labeling of moving myocardium and PN.

Demonstration of velocity selective myocardial arterial spin labeling perfusion imaging in humans

PURPOSE

Transit delay is a potential source of error in cardiac arterial spin-labeled (ASL) in heart failure or with collateral circulation. This study demonstrates the feasibility of using transit delay insensitive velocity selective ASL and compares its performance with flow-sensitive alternating inversion recovery (FAIR) ASL.

METHODS

Velocity selective labeling was achieved using an adiabatic BIR8 preparation. FAIR and velocity-selective ASL (VSASL) with various velocity cutoffs (V_C  = 10-40 cm/s) and labeling directions (anterior-posterior X, lateral-septal Y, and apical-basal Z) were carried out in 10 healthy volunteers (1F/9M age 23-30 y). Myocardial blood flow (MBF) and temporal signal-to-noise (TSNR) were measured.

RESULTS

VSASL sensitivity to perfusion decreased with increasing V_C . At low V_C (<5 cm/s), spurious labeling of myocardium occurs and overestimates MBF. MBF measured with FAIR (1.12 ± 0.26 ml/g/min) and VASL (1.26 ± 0.27 ml/g/min) at V_C of 10 cm/s in Z were comparable (TOST with difference of 0.30 ml/g/min, P = 0.049). TSNR was 2.8 times larger using FAIR (13.62 ± 5.25) than in VSASL (4.87 ± 1.58). VSASL was insensitive to perfusion in the Y direction. X and Z performed similarly with TSNR of 4.17 ± 2.32 and 3.97 ± 0.56, respectively.

CONCLUSION

VSASL is a promising alternative to FAIR ASL in the heart and is well suited for scenarios when transit delays are long. Magn Reson Med 80:272-278, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Cardiac functions assessment in children with celiac disease and its correlation with the degree of mucosal injury: Doppler tissue imaging study

BACKGROUND/AIMS

Celiac disease (CD)-associated cardiologic disorders is a growing concern. However, data regarding cardiac affection in children with CD are few. This study aimed at assessing the subclinical impact of CD on the global myocardial performance in Saudi children with CD using Doppler tissue imaging (DTI).

PATIENTS AND METHODS

Conventional two-dimensional echocardiography was performed among 20 Saudi children with CDas well as 20 age and sex-matched healthy controls. DTI were used to determine right ventricular (RV) and left ventricular (LV) Tei indexes. These findings were correlated with the Modified Marsh Classification of the histologic findings in CD.

RESULTS

LV and RV Tei indexes were significantly higher in children with CD than the control group (mean ± standard deviation: 0.47 ± 0.05 vs. 0.31 ± 0.18; P< 0.0005 and 0.51 ± 0.04 vs. 0.32 ± 0.05; P< 0.0001, respectively). RV Tei index was found to be positively correlated with the Modified Marsh Classification of CD (r = 0.7753, P< 0.0001). LV Tei index tended to be more affected in patients with more severe histologic findings, however, such relation did not reach statistical significance (r = 0.2479, P = 0.292). Fractional shortening did not correlate with the Modified Marsh Classification of histologic findings in CD patients (r= -0.11, P = 0.641).

CONCLUSIONS

Subclinical myocardial dysfunction of both ventricles occurs in children with CD. The DTI method appears to be more sensitive than conventional two-dimensional echocardiography in the early detection of myocardial dysfunction in children with CD.

Maternal obesity affects fetal myocardial function as early as in the first trimester

OBJECTIVE

To investigate cardiac function from 14 weeks' gestation in fetuses of obese pregnant women (FOW). Animal studies have shown that maternal obesity induces fibrosis in fetal myocardium. We hypothesized that fetal cardiac function would be impaired among FOW.

METHODS

A case-control study with longitudinal follow-up was performed at Trondheim University Hospital, Norway. In total, 80 pregnant women were included and the final population comprised 52 obese and 24 of normal weight (mean body mass index before pregnancy, 34.8 ± 4.1 vs 21.0 ± 2.2 kg/m(2) ; P < 0.001). The main outcome measures were global strain rate (GSR) and strain by tissue Doppler imaging, tissue Doppler velocities (TDVs) and interventricular septal thickness assessed by fetal echocardiography at gestational ages of 14, 20 and 32 weeks.

RESULTS

In FOW, fetal left ventricle (LV) and right ventricle (RV) GSR and strain were significantly lower than in fetuses of normal-weight pregnant women: LV GSR was 33.3% lower at 14 weeks, 22.4% lower at 20 weeks and 22.8% lower at 32 weeks of gestation (P < 0.001) with no difference in fetal heart rate. Systolic and late diastolic TDVs for LV were significantly lower from 20 weeks' gestation and remained lower throughout pregnancy. Fetal interventricular septum was 26.6% (P < 0.001) thicker in late pregnancy in FOW compared with normal-weight pregnancies.

CONCLUSIONS

At 14 weeks of gestation, we detected fetal myocardial dysfunction with reduced LV and RV GSR and strain in FOW compared with fetuses of women with normal weight. Our finding is alarming considering the high prevalence of obesity and may partly explain the predisposition of offspring to cardiovascular disease later in life.

Automatic Segmentation of Mechanically Inhomogeneous Tissues Based on Deformation Gradient Jump

Variations in properties, active behavior, injury, scarring, and/or disease can all cause a tissue's mechanical behavior to be heterogeneous. Advances in imaging technology allow for accurate full-field displacement tracking of both in vitro and in vivo deformation from an applied load. While detailed strain fields provide some insight into tissue behavior, material properties are usually determined by fitting stress-strain behavior with a constitutive equation. However, the determination of the mechanical behavior of heterogeneous soft tissue requires a spatially varying constitutive equation (i.e., one in which the material parameters vary with position). We present an approach that computationally dissects the sample domain into many homogeneous subdomains, wherein subdomain boundaries are formed by applying a betweenness based graphical analysis to the deformation gradient field to identify locations with large discontinuities. This novel partitioning technique successfully determined the shape, size and location of regions with locally similar material properties for: (1) a series of simulated soft tissue samples prescribed with both abrupt and gradual changes in anisotropy strength, prescribed fiber alignment, stiffness, and nonlinearity, (2) tissue analogs (PDMS and collagen gels) which were tested biaxially and speckle tracked (3) and soft tissues which exhibited a natural variation in properties (cadaveric supraspinatus tendon), a pathologic variation in properties (thoracic aorta containing transmural plaque), and active behavior (contracting cardiac sheet). The routine enables the dissection of samples computationally rather than physically, allowing for the study of small tissues specimens with unknown and irregular inhomogeneity.

Assessment of cardiac functions in children with sickle cell anemia: doppler tissue imaging study

BACKGROUND AND AIMS

The extent in which sickle cell anemia (SCA) impacts myocardial function in children is unclear. Doppler tissue imaging (DTI) was introduced as a new non-invasive echocardiographic method for assessment of ventricular systolic and diastolic functions. We undertook this study to assess subclinical impact of SCA on global myocardial performance in affected children using DTI and to correlate it with mean hemoglobin concentration.

METHODS

Eighty five children with SCA (mean age 11.82 ± 3.7 years) was included as the study group and 55 age- and sex-matched healthy children as the control group. Conventional two-dimensional echocardiography was performed in both groups and DTI was used to determine right ventricular (RV) and left ventricular (LV) Tei indexes. Mean Hb concentration was correlated to the cardiac functions of SCA children.

RESULTS

RV and LV Tei indexes were significantly higher in SCA group (mean ± SD: 0.54 ± 0.19 vs. 0.27 ± 0.01, p <0.0001 and 0.47 ± 0.09 vs. 0.30 ± 0.07, p <0.0001, respectively). Also, mean Hb concentration was correlated negatively with both LV Tei index (r = -0.611, p <0.0001) and with RV Tei index (r = -0.894, p <0.0001). On the contrary, fractional shortening (FS) did not correlate with mean Hb concentration (r = -0.044, p = 0.681).

CONCLUSIONS

DTI technique appears to be more sensitive than conventional echocardiography in the early detection of myocardial dysfunction in children with SCA. This provides insights into the value of early screening and the potential for preventive therapy in children to avert cardiac morbidity and mortality in adults with SCA.

Assessment of Myocardial Function in Children before and after Autologous Peripheral Blood Stem Cell Transplantation

BACKGROUND

Increased interest is focused on the long-term adverse effects of bone marrow transplantation. Subclinical cardiac involvement appears common in adults, but only a few reports have examined pediatric patients.

MATERIALS AND METHODS

A prospective case-control study of 19 children with normal cardiac function undergoing autologous hematopoietic stem cell transplantation (HSCT) was performed. Tissue Doppler imaging (TDI) and echocardiographic measurements were obtained according to the guidelines of the American Society of Echocardiography before and 3 months after HSCT.

RESULTS

Lateral mitral annulus before HSCT showed significant reduced mitral systolic annular velocity (P < 0.0001), early diastolic annular velocity (P < 0.0001), late diastolic annular velocity (P = 0.02) and prolonged isovolumetric relaxation time (IRT) (P < 0.0001) compared with control. Significant reduced mitral systolic annular velocity (P < 0.0001), early diastolic annular velocity (P = 0.0005) and Em/Am ratio (P = 0.004), with higher late diastolic annular velocity (P = 0.02) and prolonged isovolumetric contraction time (ICT) (P = 0.003) and IRT (P = 0.002) after HSCT, were observed. Investigation of lateral tricuspid annulus showed nearly similar results as the lateral mitral annulus. LV and RV Tei indices were higher before HSCT compared with control and remained high after HSCT.

CONCLUSION

TDI detected subtle abnormalities in systolic and diastolic functions before and after HSCT, which suggests that a conditioning regimen may affect cardiac function.

Does surgically induced right bundle branch block really effect ventricular function in children after ventricular septal defect closure?

In this prospective study, we aimed to assess left and right ventricular function in terms of the presence of right bundle branch block (RBBB) in the cases with repaired ventricular septal defect (VSD). Fifty-three patients who had VSD surgery at least 1-year preceding admission and 52 healthy controls were enrolled into the study. All the participants underwent electrocardiographic and echocardiographic examination. The cases with RBBB were determined. The conventional and tissue Doppler echocardiographic measurements of the patients with and without RBBB were compared with each other and healthy controls. Twenty-eight of VSD repair groups were male and 25 were female. Control group consisted of 30 males and 22 females. The mean age of the study and control groups was 7.5 ± 5.0 and 6.9 ± 4.3 years, respectively. RBBB was detected in 20 of 53 (37.7 %) operated patients. The only significant difference between the cases with and without RBBB was decreased right ventricular fractional area change (%) in the former group (33 ± 7 vs. 39 ± 5 p < 0.05). When compared to controls, operated group had statistically lower [corrected] tricuspid annular plane systolic excursion (p < 0.05), lower systolic, early diastolic, and late diastolic myocardial velocities, higher left and right ventricular myocardial performance indices, irrespective of the presence of RBBB. The ratios of mitral or tricuspid inflow to left or right ventricular myocardial in early diastolic velocities measured from lateral annular levels were increased in operated group (all p values <0.05). In conclusion, RBBB in the cases with surgical VSD repair might be associated with right ventricular dysfunction. Biventricular systolic and diastolic dysfunction may develop following VSD repair irrespective of the presence of RBBB. Tissue Doppler-derived myocardial performance indices are useful in detection of those subclinical dysfunctions.

Characterization of dysfunctional remote myocardium in left ventricular anterior aneurysms and improvements following surgical ventricular restoration using cardiac magnetic resonance imaging: preliminary results

OBJECTIVES

In patients with previous myocardial infarction, the remote uninfarcted regions, although contractile, demonstrate dysfunctional wall kinetics because of increased afterload, which improves after surgical ventricular restoration (SVR). We characterized left ventricular (LV) mean myocardial velocity (MMV) through an analysis of endocardial motion and wall thickening (WT) over the cardiac cycle using standard cardiac magnetic resonance (cMR).

METHODS

LV endocardial motion and WT from cMR data in 7 heart failure (HF) patients with postinfarction antero apical aneurysm were compared against normal controls to establish a baseline for the mean myocardial velocity during phases of the cardiac cycle. The HF patients' MMV and WT curves were compared with post-SVR data.

RESULTS

Global MMV showed significant postoperative improvements in the ejection phase of systole and the early filling phase of diastole. The aneurysmal wall was dyskinetic in both systole and diastole. The remote myocardium preoperatively had a delayed peak velocity during the ejection phase of systole and diminished velocity during early filling in diastole. After SVR, the remote myocardium had an increased MMV with an earlier peaking during the ejection phase and slightly improved early diastolic velocity. WT increased cumulatively during systole and decreased during diastole with improved end-systolic and end-diastolic wall thickness after SVR. The end-systolic wall thickness showed a significant correlation with left ventricular ejection fraction (r(2) = 0.89, P = 0.001) and stroke volume (r(2) = 0.80, P = 0.02). The MMV had a significant correlation with WT over the phases of the cardiac cycle (r(2) = 0.953, P ≤ 0.0001).

CONCLUSIONS

In patients with chronic ischaemic heart disease with LV aneurysms/large areas of scar, improvements in the remote myocardial MMV and WT underline LV systolic function improvements after SVR. The persistence of myocardial WT in early diastole is the likely mechanism for incomplete or absence of relief of LV diastolic dysfunction by SVR.

Assessment of No-Reflow Phenomenon by Myocardial Blush Grade and Pulsed Wave Tissue Doppler Imaging in Patients with Acute Coronary Syndrome

Background:

No-reflow phenomenon is a complication of myocardial revascularization and it is associated with a worse prognosis.

Materials and Methods:

A prospective study was carried out enrolling patients with acute myocardial infarction (64 patients, 49 male and 15 female, median age 64.9 ± 10.61 years), both STEMI and NSTEMI, who underwent myocardial revascularization with percutaneous coronary intervention (PCI). TIMI flow and Myocardial Blush Grade (MBG) were assessed at baseline (T0), in addition to tissue Doppler imaging (TDI) and electrocardiogram. Cardiological evaluation was also performed at T1 (one month after PCI) and T2 (every year after revascularization for a mean follow-up of 24.9 months ± 6.93 months). Patients were divided into two groups on the basis of MBG.

Results:

In the present study, we found at T1 a significant association between MBG and dyslipidemia (P = 0,038) and NYHA class and MBG (P = 0,040), among clinical variables and cardiovascular risk factors. Moreover, a statistically significant relationship was observed between MBG and a new echocardiographic index of systolic and diastolic dysfunction, the EAS index measured with tissue Doppler imaging (P = 0,013). At T2, the EAS parameter was also significantly impaired in patients with reduced MBG, compared to patients with normal MBG (P = 0,003).

Conclusions:

This study demonstrates that the combined evaluation of systolic and diastolic dysfunction by EAS index, according to the literature, could detect a subclinical ventricular dysfunction due to a perfusion defect. Therefore, EAS index could be a useful parameter to be measured in the follow-up of patients undergoing revascularization.

Myocardial performance in children with autoimmune hepatitis: Doppler tissue imaging study

Autoimmune hepatitis (AIH) is a member of autoimmune diseases family which can increase risk of cardiovascular morbidity and mortality. This study aimed to assess subclinical impact of AIH on global myocardial performance in affected children using Doppler tissue imaging (DTI) and to correlate it with total serum immunoglobulin-G (IgG). Thirty children with AIH (mean age = 12.67 ± 2.9 years) was included as the study group and 20 age- and sex-matched healthy children (mean age = 11.93 ± 2.66 years) as the control group. Conventional two-dimensional echocardiography was performed to both groups and DTI were used to determine right ventricular (RV) and left ventricular (LV) Tei indexes. Total serum IgG levels at initial diagnosis of AIH were correlated to the cardiac functions of AIH patients. RV and LV Tei indexes were significantly higher in AIH group (mean ± SD: 0.46 ± 0.088 vs. 0.26 ± 0.01, P < 0.0001 and 0.45 ± 0.086 vs. 0.31 ± 0.02, P < 0.0001, respectively). Also, total IgG concentrations were correlated positively with the LV Tei index (r = 0.69, P < 0.0001) and with the RV Tei index (r = 0.61, P < 0.0003) and correlated negatively with the mitral systolic (Sm) velocity (r = -0.76, P < 0.0001) and with tricuspid systolic (Sm) velocity (r = -0.66, P < 0.0001). On the other hand, fractional shortening did not correlate with serum IgG concentrations (r = -0.04, P = 0.821). In conclusion, the DTI technique appears to be more sensitive than conventional echocardiography in the early detection of myocardial dysfunction in AIH children.

Tissue Doppler imaging predicts adverse outcome in children with idiopathic pulmonary arterial hypertension

OBJECTIVE

To evaluate the clinical utility of tissue Doppler imaging (TDI) in assessment of disease severity and prognostic value in children with idiopathic pulmonary arterial hypertension (PAH).

STUDY DESIGN

A prospective study was performed to evaluate TDI velocities (systolic myocardial velocity, early diastolic myocardial relaxation velocity [Em], late diastolic myocardial velocity associated with atrial contraction), brain natriuretic peptide, New York Heart Association (NYHA) functional class, and hemodynamics in 51 children (mean age; 11.6 years) with idiopathic PAH. Fifty-one healthy children with comparable demographics served as controls.

RESULTS

Em, Em/late diastolic myocardial velocity associated with atrial contraction ratio, and systolic myocardial velocity at mitral annulus, septum, and tricuspid annulus in PAH were significantly reduced compared with controls. Tricuspid Em had significant inverse correlations with plasma brain natriuretic peptide levels (r = -0.60, P < .001), right ventricular end-diastolic pressure (r = -0.79, P < .001), and mean pulmonary arterial pressure (r = -0.67, P < .001). Statistically significant differences were observed in tricuspid Em between NYHA functional class II vs combined III and IV (mean and SD; 11.9 ± 4.2 cm/s vs 8.2 ± 3.6 cm/s, respectively, P = .002). Cumulative event-free survival rate was significantly lower when tricuspid Em was ≤8 cm/s (log-rank test, P < .001)

CONCLUSIONS

Tricuspid Em velocity correlated with NYHA functional class as disease severity and may serve as a useful prognostic marker in children with idiopathic PAH. The present study is the initial report to evaluate TDI velocities against midterm outcome variables in a relatively large pediatric PAH population.

Myocardial dysfunction in neonatal sepsis: a tissue Doppler imaging study

OBJECTIVES

To assess myocardial performance in septic full-term infants and to correlate it with serum cardiac troponin T concentrations.

DESIGN

Prospective, case-control, clinical study.

SETTING

Neonatal intensive care unit in a university hospital.

PATIENTS

Twenty septic and 20 nonseptic full-term neonates.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Conventional echocardiography, tissue Doppler imaging, and serum cardiac troponin T concentration tests were performed as soon as diagnosis was made. On tissue Doppler imaging measurements, right ventricular and left ventricular Tei indexes were significantly higher in septic neonates compared to nonseptic neonates (mean ± SD: 0.51 ± 0.09 vs. 0.28 ± 0.05, p < .001, and 0.56 ± 0.07 vs. 0.39 ± 0.04, p < .001, respectively). Mitral and tricuspid peak annular systolic velocities were significantly lower in septic neonates (mean ± SD: 4.35 ± 0.68 vs. 6.89 ± 0.94 cm/sec, p < .0001, and 5.55 ± 0.66 vs. 6.69 ± 0.87 cm/second, p < .0001, respectively). On conventional echocardiography measurements, left ventricular internal diameter at end-diastole was significantly higher in septic neonates (p = .04), whereas cardiac index and left ventricular and right ventricular diastolic functions were not significantly different between septic and nonseptic neonates. Cardiac troponin T concentrations were significantly higher in septic neonates (median [range], 0.19 [0.12- 0.32] vs. 0.03 [0-0.07] mg/L, p < .0001), and they correlated positively with left ventricular Tei index (r = .80; p < .0001) and right ventricular Tei index (r = .73; p < .0001), and correlated negatively with mitral peak annular systolic velocity (r = -.70; p < .0001) and tricuspid peak annular systolic (r = -.39, p = .012). Nonsurvivors had significantly higher serum cardiac troponin T concentrations and left ventricular Tei index.

CONCLUSIONS

Neonatal sepsis is associated with systolic and diastolic myocardial dysfunction. This study provides proof-of-concept data for the use of tissue Doppler imaging in assessment of myocardial dysfunction in septic neonates. Tissue Doppler imaging appears to be more sensitive than conventional echocardiography in the detection of this dysfunction. Serum cardiac troponin T and left ventricular Tei index may have prognostic value in these patients.

Left intraventricular diastolic and systolic pressure gradients

To describe left ventricular (LV) function comprehensively, it is crucial to characterize precisely transmitral, intraventricular and transaortic pressure–flow relations. The site of measurement is important; as the measurement location is moved from the mitral valve toward the apex and the outflow tract, important regional pressure differences are recorded inside the LV. These intraventricular pressure gradients (IVPGs) play an important role in ventricular filling in the normal heart and may be abolished by systolic or diastolic dysfunction. Despite their apparent importance in ventricular filling and diastolic function, IVPGs have never been utilized in clinical cardiology, due to the complexity of their acquisition. The application of Doppler echocardiography allows the reconstruction of diastolic IVPGs completely non-invasively, thus avoiding the risk and expense of a cardiac catheterization. Regional pressure gradients are also present during ventricular emptying but their correlation with systolic function is not so clear. The current minireview highlights theories and experimental data on invasive and non-invasive assessment of diastolic and systolic IVPGs and their role in LV filling and emptying. We also review the pathophysiological modulation of regional gradients, their importance in understanding and evaluating the complex phenomena underlying ventricular filling, as well as their potential clinical application.

Echocardiographic assessment of myocardial strain

Echocardiographic strain imaging, also known as deformation imaging, has been developed as a means to objectively quantify regional myocardial function. First introduced as post-processing of tissue Doppler imaging velocity converted to strain and strain rate, strain imaging has more recently also been derived from digital speckle tracking analysis. Strain imaging has been used to gain greater understanding into the pathophysiology of cardiac ischemia and infarction, primary diseases of the myocardium, and the effects of valvular disease on myocardial function, and to advance our understanding of diastolic function. Strain imaging has also been used to quantify abnormalities in the timing of mechanical activation for heart failure patients undergoing cardiac resynchronization pacing therapy. Further advances, such as 3-dimensional speckle tracking strain imaging, have emerged to provide even greater insight. Strain imaging has become established as a robust research tool and has great potential to play many roles in routine clinical practice to advance the care of the cardiovascular patient. This perspective reviews the physiology of myocardial strain, the technical features of strain imaging using tissue Doppler imaging and speckle tracking, their strengths and weaknesses, and the state-of-the-art present and potential future clinical applications.

Acoustic radiation force-driven assessment of myocardial elasticity using the displacement ratio rate (DRR) method

A noninvasive method of characterizing myocardial stiffness could have significant implications in diagnosing cardiac disease. Acoustic radiation force (ARF)-driven techniques have demonstrated their ability to discern elastic properties of soft tissue. For the purpose of myocardial elasticity imaging, a novel ARF-based imaging technique, the displacement ratio rate (DRR) method, was developed to rank the relative stiffnesses of dynamically varying tissue. The basis and performance of this technique was demonstrated through numerical and phantom imaging results. This new method requires a relatively small temporal (<1 ms) and spatial (tenths of mm(2)) sampling window and appears to be independent of applied ARF magnitude. The DRR method was implemented in two in vivo canine studies, during which data were acquired through the full cardiac cycle by imaging directly on the exposed epicardium. These data were then compared with results obtained by acoustic radiation force impulse (ARFI) imaging and shear wave velocimetry, with the latter being used as the gold standard. Through the cardiac cycle, velocimetry results portray a range of shear wave velocities from 0.76-1.97 m/s, with the highest velocities observed during systole and the lowest observed during diastole. If a basic shear wave elasticity model is assumed, such a velocity result would suggest a period of increased stiffness during systole (when compared with diastole). Despite drawbacks of the DRR method (i.e., sensitivity to noise and limited stiffness range), its results predicted a similar cyclic stiffness variation to that offered by velocimetry while being insensitive to variations in applied radiation force.

Prognostic significance of right ventricular dimension on acute decompensation in chronic left-sided heart failure

Right ventricular (RV) dysfunction has been discussed in relation to an adverse outcome in heart failure (HF). The aim of this study was to analyze the relationship between RV function with HF exacerbation and its subsequent long-term outcome in patients with chronic left-sided HF.We studied 122 consecutive patients who were admitted for dyspnea due to exacerbated left-sided HF with a left ventricular (LV) ejection fraction of less than 40%. Conventional echocardiography was performed in the study subjects on admission and at discharge. Cox proportional hazards analysis revealed that RV end-diastolic dimension (RVDd) (hazard ratio 1.131, P = 0.005, 95% confidence interval 1.039-1.231) and the serum level of creatinine on admission were independent predictors of subsequent cardiac-related death, but RVDd at discharge and other LV parameters were not. Thus, patients were divided into tertiles on the basis of RVDd on admission: < 32 mm (n = 37), 32-40 mm (n = 43), and ≥ 40 mm (n = 42). According to the increase in the RVDd category, the cardiac-related death-free rate significantly decreased. Among the 3 groups, the pulse pressure and serum total bilirubin levels that demonstrated low cardiac output syndrome (LOS) parameters had significant differences.RVDd on admission could be measured noninvasively and easily to predict a worse long-term prognosis of chronic left-sided HF on admission, and showed correlations with LOS parameters.

Left atrial distensibility and E/e' for estimating left ventricular filling pressure in patients with stable angina. -A comparative echocardiography and catheterization study-

BACKGROUND

Although E/e' (the ratio of early diastolic mitral inflow velocity to early diastolic mitral annular velocity) is widely used to measure left ventricular filling pressure (LVFP), its accuracy is questionable in coronary artery disease patients.

METHODS AND RESULTS

Echocardiograms and LVFP were obtained from 174 patients with stable angina (Canadian Cardiovascular Society angina grade I-II) who had received interventions for angiography-confirmed coronary stenosis. Compared with single-vessel groups, the multiple-vessel group exhibited lower mitral annular velocities, higher LVFP, and stronger correlations between E/regional e' and LVFP. Additionally, stronger correlations between E/regional e' and LVFP existed in patients with systolic dysfunction or lower variation of myocardial performance index (MPI) among anterior, inferior and lateral borders of mitral annulus. Average e' was not superior to any regional e' for assessing LVFP by the E/e' method. E/e' and left atrial (LA) ejection fraction (EF) correlated linearly with LVFP, but the correlation between LA distensibility and LVFP was logarithmical. Compared with E/e', LA distensibility and LAEF were superior for identifying high LVFP.

CONCLUSIONS

E/e' is not completely satisfactory for assessing LVFP in patients with stable angina, especially those with single-vessel disease, preserved systolic function or high MPI variation. For identifying high LVFP, LA distensibility and LAEF are better than E/e'.

Early echocardiographic findings in β-thalassemia intermedia patients using standard and tissue Doppler methods

Heart complications are among the serious problems of patients with β-thalassemia intermedia. This study aimed to evaluate myocardial function in these patients. Clinical parameters and both standard Doppler and pulsed Doppler tissue imaging parameters were compared in 51 β-thalassemia intermedia patients (mean age, 17.05 ± 5.8 years) and 20 normal subjects (mean age, 17.81 ± 7.35 years, p = 0.98). In 11 patients (21.5%), pulmonary artery hypertension was detected. M-mode echocardiographic findings such as ejection fraction and fractional shortening did not show statistically significant changes (p > 0.005). Pulsed Doppler showed a significant difference in the early (E) to late diastolic (A) velocity ratio of the tricuspid and mitral valve between the patients and the control subjects (p < 0.05). In the pulsed tissue Doppler study, the peak systolic velocity of the septum (Ss), the peak atrial velocity of the septum (Aas), the peak systolic velocity of the tricuspid annulus (St), the peak early diastolic velocity of the tricuspid annulus (Eat), and the peak late diastolic velocity of the tricuspid annulus (Aat) were increased significantly (p < 0.05). The pulse tissue Doppler of the lateral mitral annulus did not change significantly (p > 0.005). The peak systolic velocity of the posterior wall and the peak late diastolic velocity of the anterior wall changed significantly (p < 0.05). This study showed that β-thalassemia intermedia patients with normal M-mode and two-dimensional echocardiography had statistically significant changes in pulsed Doppler and pulsed tissue Doppler imaging.

Myocardial performance in asphyxiated full-term infants assessed by Doppler tissue imaging

The aim of this study was to assess myocardial performance of full-term infants with perinatal asphyxia using Doppler tissue imaging (DTI) and to correlate it with serum cardiac troponin T (cTnT) concentrations. Twenty-five asphyxiated and 20 nonasphyxiated term infants were investigated. Serum cTnT concentrations were measured between 12 and 24 h of life. Conventional two-dimensional Doppler echocardiography and DTI were done during the first 72 h of life. Right ventricular (RV) and left ventricular (LV) Tei indexes were significantly higher in asphyxiated neonates (mean +/- SD: 0.45 +/- 0.05 vs. 0.28 +/- 0.05, P < 0.001 and 0.51 +/- 0.04 vs. 0.38 +/- 0.04, P < 0.001, respectively). Mitral and tricuspid systolic (Sm) velocities were significantly lower in asphyxiated neonates (mean +/- SD: 5.06 +/- 0.89 vs. 6.89 +/- 0.94 cm/s, P < 0.001 and 5.78 +/- 0.58 vs. 6.69 +/- 0.87 cm/s, P < 0.001, respectively). cTnT concentrations were significantly higher in asphyxiated neonates [median (range): 0.17 (0.05-0.23) vs. 0.03 (0-0.07) microg/l, P < 0.001)], and they correlated positively with the LV Tei index (r = 0.67, P < 0.001) and the RV Tei index (r = 0.68, P < 0.001) and negatively with the mitral systolic (Sm) velocity (r = -0.68, P < 0.001) and tricuspid systolic (Sm) velocity (r = -0.41, P = 0.01). A higher cTnT was a significant predictor of mortality, whereas fractional shortening (FS) and DTI measurements did not show any significant predictive value. The DTI technique appears to be more sensitive than conventional echocardiography in the early detection of myocardial dysfunction induced by perinatal asphyxia in full-term infants.

Tissue Doppler imaging of right ventricular decompensation in pulmonary hypertension

Right ventricular (RV) function is closely linked to outcomes in pulmonary hypertension (PH). The authors sought to evaluate RV myocardial strain in 3 groups of patients: normal, PH with compensated RV function (PH-C), and PH with decompensated RV function (PH-D). Fifty-six patients (aged 56+/-12 years; 40 women; mean pulmonary artery pressure [MPAP] range, 13-82 mm Hg) underwent right heart catheterization and 2-dimensional echocardiography with tissue Doppler imaging of the RV. Right atrial pressures were 6+/-3, 5+/-2, and 14+/-4 mm Hg; MPAP values were 19+/-3, 44+/-15, and 56+/-13 mm Hg; pulmonary vascular resistances were 1.4+/-0.4, 7.9+/-5.1, and 11.5+/-6.6 Wood units; and cardiac indices were 3.4+/-0.9, 2.8+/-0.8, and 2.2+/-0.7 L/min/m(2) (P<.05 for all for normal, PH-C, and PH-D patients), respectively. RV free wall strain decreased significantly among all 3 groups (-26%+/-6%, -19%+/-7%, and -14%+/-5%; P<.0001). RV free wall strain decreases in PH without hemodynamically decompensated RV function suggesting it may be a preceding step in the development of RV failure. This may be of particular use in following patients sequentially.

Demonstration of regional differences in equine ventricular myocardial velocity in normal 2-year-old Thoroughbreds with Doppler tissue imaging

REASONS FOR PERFORMING STUDY

Doppler tissue imaging (DTI) is a novel noninvasive method by which myocardial velocity can be assessed directly and it allows regional, rather than global, cardiac function to be evaluated.

HYPOTHESIS

That regional differences in myocardial velocities exist within the equine ventricle.

OBJECTIVES

To develop a repeatable examination technique for DTI in horses, describe DTI findings in various regions of the normal equine ventricle, compare colour (CDTI) and spectral (SDTI) techniques of DTI, and document regional differences in myocardial velocity.

METHODS

Five regions of the ventricles (right ventricular wall, interventricular septum and left, right and caudal regions of the left ventricle) were evaluated using SDTI and CDTI in 20 clinically normal Thoroughbreds age 2 years. Individual repeatability of the method was determined by examination of one 6-year-old Thoroughbred on 6 occasions.

RESULTS

Three major movements were observed in the ventricular walls in systole, early diastole and late diastole. The interventricular septum had a complex pattern of movement. The left region of the left ventricle and interventricular septum had the most rapid movement. The individual repeatability of CDTI was poor, while in systole and early diastole, but not late diastole, SDTI produced repeatable estimates of maximal myocardial velocity. The different velocity estimates obtained with SDTI and CDTI are not interchangeable. Regional differences in the peak mean and maximal myocardial velocities were found in systole and early diastole (P<0.05), but were not identified in late diastole.

CONCLUSIONS

The SDTI modality appears to produce the most repeatable data. There are regional differences in myocardial velocity within the equine ventricles for systole and early diastole.

POTENTIAL RELEVANCE

DTI shows potential as a tool for studying regional myocardial movement both in clinical cases suspected of having myocardial dysfunction and in a research setting. In particular, SDTI offers potential as a direct and noninvasive means to study early diastolic function of the equine ventricles.

Echocardiographic evaluation of systolic heart failure

Echocardiography is the most commonly used modality for evaluating left ventricular size and function in the context of systolic heart failure. Traditional techniques, though extensively used, have their limitations and more recently several newer technologies have emerged that are more reproducible, provide prognostic information, guide therapies and have an important role in monitoring progress. This review will evaluate the traditional and more novel techniques used and briefly provide an overview of the role of echocardiography in guiding and monitoring therapies in patients with systolic heart failure.

Left ventricular systolic function of newborns with asphyxia evaluated by tissue Doppler imaging

The aim of the study was to evaluate the left ventricular systolic function of newborns with asphyxia using tissue Doppler imaging (TDI). Newborns with a history of asphyxia were divided into severe and mild groups based on their Apgar scores; normal newborns without asphyxia served as the controls. Left ventricular ejection fraction (LVEF), fraction shortening (FS), and stroke volume (SV) were measured by M-mode echocardiography at 24, 48, and 72 h after birth. The peak systolic velocity of the anterior mitral valve leaflet (Sm wave) was measured with TDI. Cardiac troponin I (CTnI) was measured. The results revealed that the LVEF and FS of the severe asphyxia group at 24 h were significantly lower than those at later time points (P < 0.01). These parameters were also significantly lower than those of the mild and control groups (P < 0.01). SV was not significantly different among the three groups. Sm wave of asphyxia groups was significantly lower than that of control group (P < 0.001). In the severe asphyxia group, Sm wave at 24 h was significantly lower than that at 48 or 72 h (P < 0.001). CTnI values of the severe asphyxia group were remarkably higher than those of the other two groups (P < 0.01). The findings of this study indicate decreased left ventricular systolic function of newborn children after asphyxia. Sm by TDI is a more sensitive indicator of left ventricular systolic function than LVEF, FS, or SV by M-mode echocardiography.

In vivo cardiac, acoustic-radiation-force-driven, shear wave velocimetry

Shear wave elasticity imaging (SWEI) was employed to track acoustic radiation force impulse (ARFI)-induced shear waves in the mid-myocardium of the left ventricular free wall (LVFW) of a beating canine heart. Shear waves were generated and tracked with a linear ultrasound transducer that was placed directly on the exposed epicardium. Acquisition was ECG-gated and coincided with the mid-diastolic portion of the cardiac cycle. Axial displacement profiles consistent with shear wave propagation were clearly evident in all SWEI acquisitions (i.e., those including an ARFI excitation); displacement data from control cases (i.e., sequences lacking an ARFI excitation) offered no evidence of shear wave propagation and yielded a peak absolute mean displacement below 0.31 microm after motion filtering. Shear wave velocity estimates ranged from 0.82 to 2.65 m/s and were stable across multiple heartbeats for the same interrogation region, with coefficients of variation less than 19% for all matched acquisitions. Variations in velocity estimates suggest a spatial dependence of shear wave velocity through the mid-myocardium of the LVFW, with velocity estimates changing, in limited cases, through depth and lateral position.

Differential strain and velocity generation along the right ventricular free wall in pulmonary hypertension

BACKGROUND

In contrast to the homogeneously distributed deformation properties within the left ventricle, the right ventricular (RV) free wall (RVFW) shows a more inhomogeneous distribution. It has been demonstrated that pulmonary hypertension (PH) results in significant RVFW mechanical delay.

OBJECTIVE

To assess the effect of the degree of pulmonary arterial systolic pressure on the RVFW strain gradient and on myocardial velocity generation.

METHODS

Peak longitudinal strain and velocity data were collected from three different segments (basal, mid- and apical) of the RVFW in 17 normal individuals and 31 PH patients.

RESULTS

A total of 144 RV wall segments were analyzed. RVFW strain values in individuals without PH were higher in the mid and apical segments than in the basal segment. In contrast, RVFW strain in PH patients was higher in basal segments and diminished toward the apex. In terms of RVFW velocities, both groups showed decremental values from basal to apical segments. Basal and mid-RVFW velocities were significantly lower in PH patients than in individuals without PH.

CONCLUSIONS

PH results in significant alterations of strain and velocity generation that occurs along the RVFW. Of these abnormalities, the reduction in strain from the mid and apical RVFW segments was most predictive of PH. It is important to be aware of these differences in strain generation when studying the effect of PH on the right ventricle. Additional studies are required to determine whether these differences are due to RV remodelling.

New Echocardiographic Techniques for Evaluating Left Ventricular Myocardial Function

Ultrasound imaging of the heart continues to play an important role in diagnosis and management of patients with cardiovascular diseases. Recent advances in ultrasound technology and introduction of newer imaging modalities have enabled improved assessment of left ventricular myocardial function. Tissue Doppler imaging and 2-dimensional speckle tracking allow more objective quantification of myocardial function in the form of tissue velocities, displacement, strain, and strain rate. Similarly, contrast-enhanced echocardiography and 3-dimensional echocardiography have provided a unique insight into left ventricular form and function that was not possible by unenhanced 2-dimensional echocardiography. In this review, the authors discuss the clinical application of these new imaging techniques in the assessment of left ventricular myocardial function.

Identifying right ventricular dysfunction with tissue Doppler imaging in pulmonary hypertension

BACKGROUND

Standard echocardiographic assessment of right ventricular (RV) function is problematic due to the complex RV geometry. We used tissue Doppler imaging to identify RV dysfunction in patients with pulmonary hypertension (PH).

METHODS

Study population consisted of 44 patients (mean age 52+/-11; 30 females) with PH who underwent color tissue Doppler imaging of the RV and right heart catheterization within 2 days of each other. Peak systolic velocity and strain were measured at the RV free wall and correlated with invasive measures of PH and RV function. Myocardial velocity and strain was also measured in 20 healthy volunteers who served as normal controls (mean age 47+/-13; 13 females).

RESULTS

PH patients had significantly reduced RV free wall velocity (6.4+/-2.1 cm/s vs. 8.2+/-2.1 cm/s; p<0.05) and RV strain (-18+/-7% vs. -28+/-6%; p<0.001) versus controls. RV peak strain demonstrated excellent correlation with transpulmonary gradient (r=0.72; p<0.001), pulmonary vascular resistance (r=0.73; p<0.001), and significant inverse correlation with cardiac index (r=-0.69; p<0.001). RV velocity had a significant, but weaker, correlation with cardiac index (r=0.33; p<0.05) and no association with transpulmonary gradient or pulmonary vascular resistance. In a multivariate model, RV strain but not RV velocity was independently associated with cardiac index.

CONCLUSIONS

RV myocardial strain demonstrated excellent correlation with hemodynamic variables indicative of RV performance in PH patients.

Utility of right ventricular tissue Doppler imaging: correlation with right heart catheterization

OBJECTIVES

The objective of this study was to correlate tissue Doppler imaging of the right ventricle (RV) with pulmonary hemodynamics in patients referred for right heart catheterization.

METHODS

Seventy subjects (mean age 54 +/- 13; 35 males) prospectively underwent tissue Doppler imaging of the RV and right heart catheterization within 1 day of each other. Peak systolic velocity and strain were measured at the RV free wall and correlated with pulmonary hemodynamics.

RESULTS

RV myocardial velocity demonstrated no correlation with any hemodynamic variable. While RV strain demonstrated significant correlation with cardiac index (r =-0.61; P < 0.001), correlations with transpulmonary gradient (r = 0.26; P < 0.05) and pulmonary vascular resistance (r = 0.30; P < 0.05) were weaker. Subgroup analysis revealed that in patients with left ventricular systolic dysfunction (n = 31), RV strain showed no correlation with any hemodynamic variable. In patients with normal left ventricular systolic function (n = 39), correlations were significant between RV strain and mean pulmonary artery pressure (r = 0.59; P < 0.001), pulmonary vascular resistance (r = 0.60; P < 0.001), and cardiac index (r =-0.67; P < 0.001).

CONCLUSIONS

RV myocardial strain correlates significantly with pulmonary hemodynamics in patients with pulmonary hypertension and normal left ventricular function. However, there is no correlation with RV performance in patients with left ventricular dysfunction.

Assessment of left ventricular functions in patients with isolated coronary artery ectasia by conventional and tissue Doppler imaging

The authors sought to determine left ventricular functions by conventional and tissue Doppler imaging in patients with isolated coronary artery ectasia and controls. Peak early (E) and late (A) mitral inflow velocity, E/A ratio, E deceleration time, and isovolumetric relaxation time were obtained. Peak systolic velocity (Sm), diastolic early (Em), and late (Am) velocities were measured by tissue Doppler imaging. Interventricular septum velocities, including peak systolic (Ss), diastolic early (Es), and late (As) velocities, were recorded. Peak early (E) velocity, E/A ratio, and E deceleration time were different in both groups. Isovolumetric relaxation time was prolonged in patients with coronary artery ectasia than controls. Em and Em/Am ratio were lower in patients with coronary artery ectasia than controls. Diastolic early and Es/As velocities were lower in patients with coronary artery ectasia compared with controls. The authors showed that mitral inflow-lateral annulus and interventricular septum velocities were lower in patients with coronary artery ectasia than controls indicating left ventricular diastolic dysfunction.

Visualization of propagation of pulse vibration along the heart wall and imaging of its propagation speed

Though myocardial viscoelasticity is essential in the evaluation of heart diastolic properties, it has never been noninvasively measured in vivo. By the ultrasonic measurement of the myocardial motion, we have already found that some pulsive waves are spontaneously excited by aortic-valve closure (AVC) at end-systole (T0) (IEEE UFFC-43(1996)791-810). Using a sparse sector scan, in which the beam directions are restricted to about 16, the pulsive waves were measured almost simultaneously at about 160 points set along the heart wall at a sufficiently high frame rate (UMB 27(2001)752-768). The consecutive spatial phase distributions clearly revealed wave propagation along the heart wall for the first time (IEEE UFFC 51(2005)1931-1942). The propagation time of the wave along the heart wall is very small and cannot be measured by conventional equipment. Based on this phenomenon, we developed a means to measure the myocardial viscoelasticity in vivo. The phase velocity of the wave is determined for each frequency component. By comparing the dispersion of the phase velocity with the theoretical one of the Lamb wave, which propagates along the viscoelastic plate (heart wall) immersed in blood, the instantaneous viscoelasticity is determined noninvasively (IEEE UFFC-51(2005)1931-1942). In this study, the phase distribution obtained by the sparse scan is interpolated and extrapolated, and then the spatial distribution of the instantaneous phase velocity of the wave components propagating from the base side to the apical side of the heart wall is obtained for the longitudinal cross-sectional image.

Abnormal right ventricular myocardial strain generation in mild pulmonary hypertension

BACKGROUND

Although right ventricular (RV) dyssynchrony has been identified in patients with severe pulmonary hypertension due to significant RV enlargement and compromise in systolic function, a more clinically relevant question pertains to RV mechanical properties in patients with mild elevation in pulmonary artery systolic pressures (PASP).

METHODS

Several echocardiographic parameters and peak longitudinal strain were measured in 40 patients and divided into two groups of 20 patients based on their PASP.

RESULTS

Group I included 20 individuals (mean age 48 +/- 16 years with a mean PASP of 27 +/- 5 mmHg) and Group II included 20 patients (mean age 63 +/- 14 years with a mean PASP of 49 +/- 7 mmHg.) All time intervals were adjusted for heart rate. RV fractional area change and tricuspid annular plane systolic excursion for Group I (62 +/- 12% and 2.74 +/- 0.56 cm) and Group II (49 +/- 14%; P < 0.02 and 2.09 +/- 0.40; P < 0.002) were both normal. However, Group II had lower peak longitudinal RV free wall (RVF) strain (-27.3 +/- 7.1 % vs. -31.9 +/- 8.7%, P < 0.04), longer time to peak RVF strain (448 +/- 57 ms vs. 411 +/- 43 ms; P < 0.03) and evidence of significant RV dyssynchrony (-83 +/- 55 ms vs. 1 +/- 17 ms, P < 0.00001) in contrast to Group I.

CONCLUSION

In conclusion, mild elevations in PASP affect the mechanical properties of the RV and result in RV dyssynchrony despite absence of gross abnormalities in RV size or function.

Correlation of Tricuspid Annular Velocities With Invasive Hemodynamics in Pulmonary Hypertension

The authors performed tissue Doppler imaging of the tricuspid annulus in patients with pulmonary hypertension to assess its correlation with invasive indices of right ventricular function. The study population consisted of 32 patients with suspected pulmonary hypertension who underwent pulsed tissue Doppler imaging of the tricuspid annulus and right heart catheterization. Peak systolic (Sa), early diastolic (Ea), and late diastolic (Aa) velocities of the lateral tricuspid annulus were measured and correlated with hemodynamic variables. Peak Sa demonstrated excellent correlation with hemodynamic variables, including cardiac index (r=0.78; P<.001), pulmonary vascular resistance (r=-0.79; P<.001), and transpulmonary gradient (r=-0.72; P<.001). Peak Sa <10 cm/s predicted cardiac index <2.0 L/min/m2 with 89% sensitivity and 87% specificity. In conclusion, tissue Doppler imaging of the tricuspid annulus is a complementary method to assess right ventricular function in pulmonary hypertensive patients.

Diastolic heart failure in anaesthesia and critical care

Diastolic heart failure is an underestimated pathology with a high risk of acute decompensation during the perioperative period. This article reviews the epidemiology, risk factors, pathophysiology, and treatment of diastolic heart failure. Although frequently underestimated, diastolic heart failure is a common pathology. Diastolic heart failure involves heart failure with preserved left ventricular (LV) function, and LV diastolic dysfunction may account for acute heart failure occurring in critical care situations. Hypertensive crisis, sepsis, and myocardial ischaemia are frequently associated with acute diastolic heart failure. Symptomatic treatment focuses on the reduction in pulmonary congestion and the improvement in LV filling. Specific treatment is actually lacking, but encouraging data are emerging concerning the use of renin-angiotensin-aldosterone axis blockers, nitric oxide donors, or, very recently, new agents specifically targeting actin-myosin cross-bridges.

Tissue Doppler imaging a new prognosticator for cardiovascular diseases

Tissue Doppler imaging (TDI) is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular (LV) systolic and diastolic function. Recent studies have explored the prognostic role of TDI-derived parameters in major cardiac diseases, such as heart failure, acute myocardial infarction, and hypertension. In these conditions, myocardial mitral annular or basal segmental (Sm) systolic and early diastolic (Ea or Em) velocities have been shown to predict mortality or cardiovascular events. In particular, those with reduced Sm or Em values of <3 cm/s have a very poor prognosis. In heart failure and after myocardial infarction, noninvasive assessment of LV diastolic pressure by transmitral to mitral annular early diastolic velocity ratio (E/Ea or E/Em) is a strong prognosticator, especially when E/Ea is > or =15. In addition, systolic intraventricular dyssynchrony measured by segmental analysis of myocardial velocities is another independent predictor of adverse clinical outcome in heart failure subjects, even when the QRS duration is normal. In heart failure patients who received cardiac resynchronization therapy, the presence of systolic dyssynchrony at baseline is associated with favorable LV remodeling, which in turn predicts a favorable long-term clinical outcome. Finally, TDI and derived deformation parameters improve prognostic assessment during dobutamine stress echocardiography. A high mean Sm value in the basal segments of patients with suspected coronary artery disease is associated with lower mortality rate or myocardial infarction and is superior to the wall motion score.

Full motion and flow field recovery from echo Doppler data

We present a new computational method for reconstructing a vector velocity field from scattered, pulsed-wave ultrasound Doppler data. The main difficulty is that the Doppler measurements are incomplete, for they do only capture the velocity component along the beam direction. We thus propose to combine measurements from different beam directions. However, this is not yet sufficient to make the problem well posed because 1) the angle between the directions is typically small and 2) the data is noisy and nonuniformly sampled. We propose to solve this reconstruction problem in the continuous domain using regularization. The reconstruction is formulated as the minimizer of a cost that is a weighted sum of two terms: 1) the sum of squared difference between the Doppler data and the projected velocities 2) a quadratic regularization functional that imposes some smoothness on the velocity field. We express our solution for this minimization problem in a B-spline basis, obtaining a sparse system of equations that can be solved efficiently. Using synthetic phantom data, we demonstrate the significance of tuning the regularization according to the a priori knowledge about the physical property of the motion. Next, we validate our method using real phantom data for which the ground truth is known. We then present reconstruction results obtained from clinical data that originate from 1) blood flow in carotid bifurcation and 2) cardiac wall motion.

Evaluation of cardiac global function using the myocardial performance index by tissue Doppler echocardiography in patients with uremia

OBJECTIVE

The purpose of this study was to assess global ventricular function in patients with uremia by means of the myocardial performance index (MPI) derived from tissue Doppler echocardiography.

METHODS

According to the left ventricular mass index and pericardial effusion, 45 patients with uremia were classified into 2 groups: a uremia group and a uremia with pericardial effusion group. To calculate left ventricular MPI (LVMPI) and right ventricular MPI (RVMPI) by tissue Doppler echocardiography, the isovolumic contraction time (ICT), isovolumic relaxation time (IRT), and ejection time (ET) were measured at different sites in the mitral and tricuspid annuli.

RESULTS

The mean ICT and IRT were longer, the ET was shorter, and the LVMPI and RVMPI were higher in the 2 disease groups than in a control group, and the indices were higher in the uremia with pericardial effusion group than in the uremia group. The increase of the LVMPI was more obvious than that of the RVMPI. There was a significant difference in the mean LVMPI and RVMPI among the 3 groups (P<.01). The MPI was positively correlated with the IRT and the sum of the ICT and IRT and negatively correlated with the ET.

CONCLUSIONS

Both left and right ventricular systolic and diastolic function are impaired in patients with uremia. The MPI could be measured by tissue Doppler echocardiography, and we suggest that this index provides a novel, noninvasive method for clinical research on global myocardial performance in patients with uremia.

Right ventricular dyssynchrony in heart failure: a tissue Doppler imaging study

BACKGROUND

The development of right ventricular dysfunction is a poor prognostic sign in patients with heart failure (HF). Although left ventricular dyssynchrony has been well described, it is not known whether right ventricular dyssynchrony coexists in HF. We used tissue Doppler imaging to determine whether right ventricular dyssynchrony is also present in HF patients.

METHODS AND RESULTS

In 34 HF patients (mean age 56 +/- 13 years), we measured longitudinal strain at the right ventricular free wall, interventricular septum, and left ventricular lateral wall. Right ventricular and left ventricular dyssynchrony were defined as the difference in time to peak strain between the right ventricular free wall and the septum and between the left ventricular lateral wall and septum, respectively. Mean right ventricular dyssynchrony was 59 +/- 45 ms and the mean left ventricular dyssynchrony was 80 +/- 62 ms. We found a strong correlation between right ventricular dyssynchrony and pulmonary artery systolic pressure (r = 0.73; P < .001) and a negative correlation between right ventricular dyssynchrony and right ventricular fractional area change (r = -0.43; P < .02).

CONCLUSION

HF patients exhibit right ventricular dyssynchrony by strain imaging which correlates with pulmonary hypertension and right ventricular dysfunction.