How accurate is visual assessment of synchronicity in myocardial motion? An In vitro study with computer-simulated regional delay in myocardial motion: clinical implications for rest and stress echocardiography studies

The clinical value of noninvasive left ventricular myocardial work in the diagnosis of myocardial ischemia in coronary heart disease: a comparative study with coronary flow reserve fraction

The prompt and precise identification of hemodynamically significant coronary artery lesions remains an ongoing challenge. This study investigated the diagnostic value of non-invasive global left ventricular myocardial work indices by echocardiography in functional status of coronary artery disease (CAD) patients with myocardial ischemia using fractional flow reserve (FFR) as the gold standard. A total of 77 consecutive patients with clinically suspected CAD were prospectively enrolled. All participants sequentially underwent echocardiography, invasive coronary angiography (ICA) and FFR measurement. According to the results of ICA, patients were divided into myocardial ischemia group (FFR ≤ 0.8, n = 27) and non-myocardial ischemia group (FFR > 0.8, n = 50). Myocardial work indices including global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE), global positive work (GPW), global negative work (GNW), global systolic constructive work (GSCW) and global systolic wasted work (GSWW) were obtained by using the non-invasive left ventricular pressure strain loop (PSL) technique. Compared with the non-myocardial ischemia group, GWI, GCW, GPW and GSCW were significantly decreased in the myocardial ischemia group at either the 18-segment level or the 12-segment level (P < 0.001). At the 18-segment level, GWI < 1783.6 mmHg%, GCW < 1945.4 mmHg%, GPW < 1788.7 mmHg% and GSCW < 1916.5 mmHg% were optimal cut-off value to detect myocardial ischemia with an FFR ≤ 0.8. Global left ventricular myocardial work indices by echocardiography exhibited a good diagnostic value in patients with CAD and may have a good clinical significance for the screening of suspected myocardial ischemia.

A Comparative Analysis of Apical Rocking and Septal Flash: Two Views of the Same Systole?

Heart failure (HF) is a complex medical condition characterized by both electrical and mechanical dyssynchrony. Both dyssynchrony mechanisms are intricately linked together, but the current guidelines for cardiac resynchronization therapy (CRT) rely only on the electrical dyssynchrony criteria, such as the QRS complex duration. This possible inconsistency may result in undertreating eligible individuals who could benefit from CRT due to their mechanical dyssynchrony, even if they fail to fulfill the electrical criteria. The main objective of this literature review is to provide a comprehensive analysis of the practical value of echocardiography for the assessment of left ventricular (LV) dyssynchrony using parameters such as septal flash and apical rocking, which have proven their relevance in patient selection for CRT. The secondary objectives aim to offer an overview of the relationship between septal flash and apical rocking, to emphasize the primary drawbacks and benefits of using echocardiography for evaluation of septal flash and apical rocking, and to offer insights into potential clinical applications and future research directions in this area. Conclusion: there is an opportunity to render resynchronization therapy more effective for every individual; septal flash and apical rocking could be a very useful and straightforward echocardiography resource.

Non-invasive myocardial work is reduced during transient acute coronary occlusion

Background

During ischemia a close relationship exists between sub-endocardial blood flow and myocardial function. Strain parameters can capture an impairment of regional longitudinal function but are load dependent. Recently, a novel non-invasive method to calculate Myocardial Work (MW) showed a strong correlation with invasive work measurements.

Our aim was to investigate the ability of non-invasive MW indices to identify the ischaemic risk area during transient acute coronary occlusion (TACO).

Methods and results

The study population comprises 50 individuals with critical coronary stenosis (CCS). Echocardiography recordings were obtained before coronary angiography, during TACO and after revascularization to measure global longitudinal strain (GLS), Myocardial Work Index (MWI), Myocardial Constructive Work (MCW), Myocardial Wasted work (MWW), Myocardial work efficiency (MWE).

Compared to baseline, we found a significant reduction of GLS (p = 0.005), MWI, MCW and MWE (p<0.001) during TACO.

Conclusions

The non-invasive measurement of MW parameters is a sensitive and early marker of myocardial ischemia during TACO.

Left Ventricular Relaxation Half-Time as a Predictor of Cardiac Events in Idiopathic Dilated Cardiomyopathy and Hypertrophic Cardiomyopathy With Left Ventricular Systolic and/or Diastolic Dysfunction

PURPOSE

Diastolic dysfunction preceding systolic dysfunction is considered an important interaction in cardiomyopathy with poor prognosis. The aim of this study was to compare left ventricular (LV) isovolumic relaxation with the other parameters as a potential prognostic marker for patients with idiopathic dilated cardiomyopathy (IDC) and hypertrophic cardiomyopathy (HC).

METHODS

A total of 145 patients with IDC and 116 with HC were evaluated for hemodynamic parameters; LV pressure was directly measured by a micromanometer catheter, and relaxation half-time (T_1/2) was used to determine LV isovolumic relaxation. The median follow-up period was 4.7 years.

RESULTS

The mean ages of the patients with IDC and HC were 52.0 ± 12.0 and 57.1 ± 12.4 years, respectively. Each patient group was further divided into 2 groups based on the median value of T_1/2: (1) <41.0 ms (D-L group) and ≥41.0 ms (D-H group) (2) <38.5 ms (H-L group) and ≥38.5 ms (H-H group). Kaplan-Meier analysis showed a significantly higher probability of cardiac events in the D-H group than in the D-L group (p = 0.001) and in the H-H group than in the H-L group (p = 0.028). Further, Cox proportional hazard regression analysis revealed that T_1/2 was an independent predictor of cardiac events for patients with IDC (hazard ratio 1.109; p = 0.007) and HC (hazard ratio 1.062; p = 0.041). In conclusion, regardless of the type of cardiomyopathy, T_1/2 as a measure of LV isovolumic relaxation function was found to be associated with the occurrence of cardiac events.

Machine learning of the spatio-temporal characteristics of echocardiographic deformation curves for infarct classification

The aim of this study was to analyze the whole temporal profiles of the segmental deformation curves of the left ventricle (LV) and describe their interrelations to obtain more detailed information concerning global LV function in order to be able to identify abnormal changes in LV mechanics. The temporal characteristics of the segmental LV deformation curves were compactly described using an efficient decomposition into major patterns of variation through a statistical method, called Principal Component Analysis (PCA). In order to describe the spatial relations between the segmental traces, the PCA-derived temporal features of all LV segments were concatenated. The obtained set of features was then used to build an automatic classification system. The proposed methodology was applied to a group of 60 MRI-delayed enhancement confirmed infarct patients and 60 controls in order to detect myocardial infarction. An average classification accuracy of 87% with corresponding sensitivity and specificity rates of 89% and 85%, respectively was obtained by the proposed methodology applied on the strain rate curves. This classification performance was better than that obtained with the same methodology applied on the strain curves, reading of two expert cardiologists as well as comparative classification systems using only the spatial distribution of the end-systolic strain and peak-systolic strain rate values. This study shows the potential of machine learning in the field of cardiac deformation imaging where an efficient representation of the spatio-temporal characteristics of the segmental deformation curves allowed automatic classification of infarcted from control hearts with high accuracy.

Comprehensive Modeling and Visualization of Cardiac Anatomy and Physiology from CT Imaging and Computer Simulations

In clinical cardiology, both anatomy and physiology are needed to diagnose cardiac pathologies. CT imaging and computer simulations provide valuable and complementary data for this purpose. However, it remains challenging to gain useful information from the large amount of high-dimensional diverse data. The current tools are not adequately integrated to visualize anatomic and physiologic data from a complete yet focused perspective. We introduce a new computer-aided diagnosis framework, which allows for comprehensive modeling and visualization of cardiac anatomy and physiology from CT imaging data and computer simulations, with a primary focus on ischemic heart disease. The following visual information is presented: (1) Anatomy from CT imaging: geometric modeling and visualization of cardiac anatomy, including four heart chambers, left and right ventricular outflow tracts, and coronary arteries; (2) Function from CT imaging: motion modeling, strain calculation, and visualization of four heart chambers; (3) Physiology from CT imaging: quantification and visualization of myocardial perfusion and contextual integration with coronary artery anatomy; (4) Physiology from computer simulation: computation and visualization of hemodynamics (e.g., coronary blood velocity, pressure, shear stress, and fluid forces on the vessel wall). Substantially, feedback from cardiologists have confirmed the practical utility of integrating these features for the purpose of computer-aided diagnosis of ischemic heart disease.

Anthracycline or trastuzumab-related cardiotoxicity: do we have a predictive biomarker?

Chemotherapy-induced cardiotoxicity, is a well-known and potentially serious complication strongly impacting the quality of life and overall survival of breast cancer patients. The current diagnostic approach to detect cardiac damage is the estimation of left ventricular ejection fraction by echocardiography. However, this approach exhibits less sensitivity toward early prediction of cardiomyopathy, not allowing for preventive strategies. Measurement of serum cardiac-specific biomarkers can be a valid diagnostic tool for identifying patients prone to developing cardiotoxocity and in whom closer cardiac monitoring and preventive strategies are pivotal. In this article, we review work done on biomarkers in recent years, with an emphasis on troponin and B-type natriuretic peptide, which are currently the most studied in this field. We also briefly discuss current and emerging imaging techniques for early detection of cardiomyopathy.

Strain Analysis in the Detection of Myocardial Infarction at the Acute and Chronic Stages

BACKGROUND

Myocardial ischemia causes contractile dysfunction in ischemic, stunned, and tethered regions with larger infarcted zones having a negative prognostic impact on patients' outcomes. To distinguish the infarcted myocardium from the other regions, we investigated the diagnostic potential of circumferential strain (CS) and radial strain (RS) during the acute and chronic stages of myocardial infarction.

METHODS

Ten pigs underwent 90-minute occlusion of the left anterior descending artery, followed by reperfusion. Echocardiography was performed at baseline, after 90-minute occlusion, and at 2 hours, 30, and 60 days postreperfusion. CS and RS were measured using speckle tracking echocardiography. Subsequently, the pigs were sacrificed, and histological analysis for infarct size was performed.

RESULTS

After 90-minute occlusion, reduced strains were detected for all segments (infarcted anterior wall - baseline: CS: -17.6 ± 5.7%, RS: 54.4 ± 16.9%; 90 min: CS: -10.3 ± 3.0%, RS: 23.3 ± 7.0%; tethered posterior wall - baseline: CS: -18.4 ± 3.5%, RS: 68.7 ± 21.1%; 90 min: CS: -10.7 ± 6.4%, RS: 34.5 ± 14.7%, P < 0.001). However, postsystolic shortening was detected only in the infarcted segments, and the time-to-peak CS was 25% longer (P < 0.05). At 30 and 60 days postreperfusion, time-to-peak CS could only detect large scars in the anterior and anterior-septum walls (P < 0.05), while peak CS also detected smaller scars in the lateral wall (P < 0.05). RS failed to distinguish between normal, stunned/tethered, and infarcted myocardium.

CONCLUSIONS

During occlusion and 2 hours postreperfusion, time-to-peak CS could distinguish between infarcted and stunned/tethered myocardial segments, while at 30 and 60 days postreperfusion, peak CS was the best detector of infarction.

Dilated Cardiomyopathy: Normalized Multiparametric Myocardial Strain Predicts Contractile Recovery

BACKGROUND

Left ventricular contractile injury in dilated cardiomyopathy (DCM) may occur in a consistently heterogeneous distribution, suggesting that early-injury sentinel regions may have prognostic significance. Heightened surveillance of these regions with high-resolution contractile metrics may predict recovery in DCM.

METHODS

Multiple three-dimensional strain parameters were calculated at each of 15,300 left ventricular grid points from systolic displacement data obtained from cardiac magnetic resonance imaging in 124 test subjects. In 24 DCM patients, Z-scores for two strain parameters at each grid point were calculated by comparison of patient-specific strain values to respective point-specific mean and standard deviation values from a normal human strain database (n = 100). Multiparametric strain Z-scores were averaged over six left ventricular regions at basilar, mid, and apical levels (18 subregions). Patients with DCM were stratified into three groups on the basis of a blinded review of clinical contractile recovery (complete, n = 7; incomplete, n = 7; none, n = 10).

RESULTS

Basilar-septal subregions were consistently heavily injured. Basilar-septal Z-scores were significantly larger (worse) than those for the rest of the left ventricle (2.73 ± 1.27 versus 2.22 ± 0.83; p = 0.011) and lateral wall (2.73 ± 1.27 versus 1.44 ± 0.72; p < 0.001). All patients with sentinel region average multiparametric strain Z-scores less than two standard deviations (n = 6) experienced complete recovery, whereas 17 of 18 DCM patients with Z-scores greater than two standard deviations experienced incomplete or no contractile recovery.

CONCLUSIONS

Contractile injury in DCM is heterogeneous, with basilar-septal regions injured more than lateral regions. The targeting of early-injury sentinel regions for heightened surveillance with high-resolution metrics of microregional contractile function may accurately predict recovery on medical therapy. A two standard deviation Z-score threshold may predict contractile recovery.

Echocardiographic Evaluation of Left Atrial Mechanics: Function, History, Novel Techniques, Advantages, and Pitfalls

Left atrial (LA) functional analysis has an established role in assessing left ventricular diastolic function. The current standard echocardiographic parameters used to study left ventricular diastolic function include pulsed-wave Doppler mitral inflow analysis, tissue Doppler imaging measurements, and LA dimension estimation. However, the above-mentioned parameters do not directly quantify LA performance. Deformation studies using strain and strain-rate imaging to assess LA function were validated in previous research, but this technique is not currently used in routine clinical practice. This review discusses the history, importance, and pitfalls of strain technology for the analysis of LA mechanics.

Quantifying "normalized" regional left ventricular contractile function in ischemic coronary artery disease

OBJECTIVE

When significant coronary lesions are identified by angiography, regional left ventricular (LV) contractile function often plays a role in determining candidacy for revascularization. To improve on current subjective and nonquantitative metrics of regional LV function, we tested a z-score "normalization" of regional strain information quantified from clinically acquired high-resolution LV geometric datasets.

METHODS

Test subjects (n = 120) underwent cardiac MRI with multiple 3-dimensional strain parameters calculated from tissue tag-plane displacement data. Sixty healthy volunteers contributed strain parameter data at each of 15,300 LV grid points, to form a normal human strain database. Point-specific database comparisons were made in 60 patients who had documented coronary artery disease (CAD), by angiography. Patient-specific, color-coded 3-dimensional LV maps of z-score-normalized contractile function were generated.

RESULTS

Blinded clinical review indicated that 55% (33 of 60) of the patients with CAD had significant regional contractile abnormalities by 1 of 3 "gold-standard" criteria: (1) Q waves on electrocardiography (ECG); (2) infarct on radionuclide single-photon emission computed tomography (SPECT); or (3) akinesia or dyskinesia on echocardiography. Consistency among all gold-standard metrics was found for only 19% (6 of 31) of patients with CAD who had ≥2 available metrics. Blinded MRI-based, multiparametric, strain z-score localization of contractile abnormalities was accurate in 89% (ECG), 97% (SPECT), and 95% (echocardiography).

CONCLUSIONS

Nonsubjective normalization of regional LV contractile function by z-score calculation from a normal human strain database can localize and quantitatively display regional wall motion abnormalities in patients with CAD. This high-resolution localization of regional wall motion abnormalities may help improve the accuracy of therapeutic intervention in patients who have CAD.

Value of two-dimensional strain imaging in prediction of myocardial function recovery after percutaneous revascularization of infarct-related artery

BACKGROUND

Speckle tracking is integrated into echocardiographic systems for evaluation of left ventricular (LV) function by means of automated function imaging (AFI). This study aimed at evaluating role of AFI-based strain in predicting postpercutaneous coronary intervention (PCI) LV function recovery.

METHODS

Fifty patients with anterior wall myocardial infarction and impaired LV ejection fraction (LVEF) were prospectively enrolled. All patients showed positive viability results concerning left anterior descending (LAD) artery territory using low-dose dobutamine stress echocardiography (LDSE). All patients underwent strain imaging using AFI (before and after PCI).

RESULT

Mean age of the study population was 56.2 ± 5.4 years, 34 (68%) being males. 24 (48%) patients showed post-PCI LV function recovery after 4 months. They showed higher pre-PCI LVEF and AFI-based strain values. Logistic regression analysis presented baseline LVEF as an independent predictor of LV function recovery (Odds ratio = 0.7026, 95% CI: 0.54-0.93). A pre-PCI AFI strain value of -4.5% (sensitivity: 84% and specificity: 75%) for LAD territory and -9.5% (sensitivity and specificity of 50%) for global LV predicted LV function recovery.

CONCLUSION

Assessment of global and territorial LV strains using AFI; is of added value upon viability assessment using LDSE. Higher baseline LVEF and strain values are associated with post-PCI LV function recovery.

Tissue Doppler, strain and strain rate in ischemic heart disease "how I do it"

Echocardiography is the standard method for assessing myocardial function in patients with ischemic heart disease. The acquisition and interpretation of echocardiographic images, however, remains a highly specialized task which often relies entirely on the subjective visual assessment of the reader and requires therefore, particular training and expertise. Myocardial deformation imaging allows quantifying myocardial function far beyond what can be done with sole visual assessment. It can improve the interpretation of regional dysfunction and offers sensitive markers of induced ischemia which can be used for stress tests. In the following, we recapitulate shortly the pathophysiological and technical basics and explain in a practical manner how we use this technique in investigating patients with ischemic heart disease.

Regional strain determination and myocardial infarction detection by three-dimensional echocardiography with varied temporal resolution

BACKGROUND

Three-dimensional echocardiography (3DE) is a promising method for strain determination; however, there are temporal resolution concerns. This study aims to evaluate the feasibility and accuracy of 3DE on longitudinal and circumferential strain (LS, CS) determination and infarction detection under variable frame rates (FR) and "heart rates" (stroke rates [SR]) conditions.

METHODS

Latex balloons were sewn into the left ventricle (LV) of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus at stroke volumes (SV) 30-70 mL. The hearts were pumped at 2 normal limits of human heart rate. Full-volume data were acquired before and after a simulated myocardial infarction (MI) at the 2 most commonly used FRs. LS and CS values were evaluated against sonomicrometry.

RESULTS

Longitudinal strain and CS derived from high FR acquisitions showed statistically superior correlations with sonomicrometry data (LS: R(2) = 0.85, CS: R(2) = 0.84) than strain values from low FR (LS: R(2) = 0.78, CS: R(2) = 0.76) (all P < 0.01). After MI induction, LS and CS at different FRs were significantly decreased while maintaining excellent correlations with sonomicrometry data (all P < 0.001). There is no statistical difference of strain values between different SR acquisitions.

CONCLUSION

Three-dimensional wall-motion tracking has the ability to accurately determine regional myocardial deformation and detect MI. Different heart rates within a physiologically relevant range have no effect on 3D strain accuracy. Strain values calculated from higher frame rate acquisitions were found to have a slightly better accuracy.

Perioperative assessment of myocardial deformation

Evaluation of left ventricular performance improves risk assessment and guides anesthetic decisions. However, the most common echocardiographic measure of myocardial function, the left ventricular ejection fraction (LVEF), has important limitations. LVEF is limited by subjective interpretation that reduces accuracy and reproducibility, and LVEF assesses global function without characterizing regional myocardial abnormalities. An alternative objective echocardiographic measure of myocardial function is thus needed. Myocardial deformation analysis, which performs quantitative assessment of global and regional myocardial function, may be useful for perioperative care of surgical patients. Myocardial deformation analysis evaluates left ventricular mechanics by quantifying strain and strain rate. Strain describes percent change in myocardial length in the longitudinal (from base to apex) and circumferential (encircling the short-axis of the ventricle) direction and change in thickness in the radial direction. Segmental strain describes regional myocardial function. Strain is a negative number when the ventricle shortens longitudinally or circumferentially and is positive with radial thickening. Reference values for normal longitudinal strain from a recent meta-analysis by using transthoracic echocardiography are (mean ± SD) -19.7% ± 0.4%, while radial and circumferential strain are 47.3% ± 1.9% and -23.3% ± 0.7%, respectively. The speed of myocardial deformation is also important and is characterized by strain rate. Longitudinal systolic strain rate in healthy subjects averages -1.10 ± 0.16 s. Assessment of myocardial deformation requires consideration of both strain (change in deformation), which correlates with LVEF, and strain rate (speed of deformation), which correlates with rate of rise of left ventricular pressure (dP/dt). Myocardial deformation analysis also evaluates ventricular relaxation, twist, and untwist, providing new and noninvasive methods to assess components of myocardial systolic and diastolic function. Myocardial deformation analysis is based on either Doppler or a non-Doppler technique, called speckle-tracking echocardiography. Myocardial deformation analysis provides quantitative measures of global and regional myocardial function for use in the perioperative care of the surgical patient. For example, coronary graft occlusion after coronary artery bypass grafting is detected by an acute reduction in strain in the affected coronary artery territory. In addition, assessment of left ventricular mechanics detects underlying myocardial pathology before abnormalities become apparent on conventional echocardiography. Certainly, patients with aortic regurgitation demonstrate reduced longitudinal strain before reduction in LVEF occurs, which allows detection of subclinical left ventricular dysfunction and predicts increased risk for heart failure and impaired myocardial function after surgical repair. In this review, we describe the principles, techniques, and clinical application of myocardial deformation analysis.

Diagnostic Value of 2D Strain Imaging In Patients with Suspected Coronary Artery Disease

Background: Strain imaging (SI) has been shown to quantify regional myocardial function in both acute ischemic myocardium and infarcted myocardium. The aim of this study is to determine the diagnostic value of SI for the detection of coronary lesions in pts with chest pain, but without apparent wall motion abnormalities. Methods: SI for advanced wall motion analysis was performed in 59 pts with suspicious stable angina (SA) and in 57 pts with suspicious unstable angina (UA), prior to coronary angiography (CAG). Longitudinal strain was measured in 3 apical views. For the identification of ischemia a magnitude parameter, being defined as a reduction of the peak systolic strain, was used. A homogenous pattern of strain was defined as relatively uniform distribution of the peak systolic strain. Heterogeneity of strain was considered abnormal; these segments were called strain (+) and the rest were called strain (-). Results: Out of the 59 SA patients, 28 had >70% stenosis (ischemic-SA) and 31 had normal coronary anatomy or 50% stenosis (normal-SA). Of the 28 patients in the ischemic-SA group, 9 patients (32%) showed a homogeneous pattern of peak systolic strain throughout the wall (strain negative) and 19 patients (67%) showed heterogeneity of strain (strain positive). 31 patients with normal coronary anatomy or <50% stenosis (normal-SA), 6 patients (19%) showed heterogeneity of strain (strain positive) and 25 patients (80%) showed a homogeneous pattern of peak systolic strain throughout the wall (strain negative). The positive predictive value of strain was 76% in the SA group. In the group of 57 UA patients, 32 had >70% stenosis (ischemic-UA), and 25 had normal coronary anatomy or 50% stenosis (normal-UA). From the 32 patients in the ischemic-UA group, 7 patients (22%) were determined to be strain negative, and 25 patients (78%) were determined to be strain positive. Out of 25 patients with normal coronary anatomy or 50% stenosis (normal-UA), 25 patients (80%) showed a homogeneous pattern of peak systolic strain throughout the wall (strain negative) and 6 patients (19%) showed heterogeneity of strain (strain positive). The positive predictive value of strain was 80.6% in the UA group. Sensitivity and specificity of 2D strain was evaluated using diagnostic test. The results were: 68% and 80.6% respectively in the stable angina group and 78% and 76% respectively in the unstable angina group.Conclusion: Ultrasound-based SI demonstrates a strong correlation with CAG and it has potential as a non-invasive diagnostic tool for detecting CAD in pts with chest pain and without wall motion abnormalities.

Effect of coronary artery bypass surgery on left ventricular function as assessed by strain and strain rate imaging

INTRODUCTION

This study examined the effect of coronary artery revascularization on left ventricular function and the results of strain imaging for the detection of ischemia before and after coronary artery bypass graft (CABG) surgery.

MATERIAL AND METHODS

Sixty-eight patients with a history of coronary artery disease (CAD) were included, prospectively. Conventional echocardiography and color tissue Doppler-derived strain-strain rate echocardiographic imaging were performed 24 hours before and 3 months after CABG surgery.

RESULTS

While strain rate values of the basal septum, middle segment of the lateral wall, middle segment of the inferior wall, and middle and basal segments of the anterior wall were significantly increased, other segments did not change after the operation. The mean systolic strain rate value was significantly increased after the operation. Left ventricle strain values in the middle segment of the septum, middle and basal segments of the inferior wall, and middle and basal segments of the anterior wall were significantly increased after the operation. No significant difference was noted in the basal septum or the middle and basal segments of the lateral wall after the operation. The mean systolic strain value was significantly increased after the operation.

CONCLUSION

The results of this study suggest that strain and strain rate echocardiography can provide an accurate evaluation of regional contractile function after CABG, even in the segments that are apparently normal.

Mitral Annular Systolic Velocities Predict Left Ventricular Wall Motion Abnormality During Dobutamine Stress Echocardiography

Background

Longitudinal systolic left ventricular contraction is complementary to the radial performance and can be assessed using tissue Doppler imaging (TDI). This study was performed to evaluate the contribution of mitral annular systolic velocities using TDI after dobutamine stress echocardiography (DSE).

Methods and Results

Fifty subjects with suspected coronary artery disease and chest pain were examined, using DSE as usual, as well as TDI imaging of the mitral annulus at the septal, lateral, inferior, anterior, posterior regions and the proximal anteroseptal region from the apical views, before and immediately after DSE. In 24 subjects the study was normal, while wall motion abnormality was seen in 26, 9 of them only after DSE. Mitral annular systolic velocity at the 6 locations increased significantly after DSE both in normal subjects and in those with wall motion abnormality (WMA). After DSE mitral annular septal systolic velocity in normals, 19.2 ± 3.8 cm/sec, was higher than in those with WMA, 14.6 ± 2.5 cm/sec, P < 0.0003. Post-DSE mitral systolic velocity was senstive and accurate in predicting WMA.

Conclusions

Systolic mitral TDI velocities increase after DSE, however to a lesser extent in those with wall motion abnormality, and can differentiate them from normal subjects.

Prominent papillary muscles in Fabry disease: a diagnostic marker?

Fabry disease is often linked with a prominent papillary muscle. It remains unknown whether this sign could be used as a diagnostic marker to screen for Fabry patients. Standard echo was performed in 101 consecutive patients with concentric left ventricular (LV) hypertrophy (28 Fabry, 30 Friedreich, 34 isolated arterial hypertension, 9 amyloidosis) and 50 healthy controls. In addition, the areas of both papillary muscles, as well as the LV endocardial circumference, were manually traced in short axis views. A ratio of papillary muscle size to LV circumference was calculated (PM_LV_ratio). The papillary muscle area was positively correlated to LV wall thickness in this cohort (p < 0.0001; r = 0.58). In all patient subgroups, the absolute papillary muscle area was significantly enlarged and the PM_LV_ratio was significantly higher when compared with controls. However, Fabry patients showed a significantly larger absolute papillary muscle area than Friedreich and amyloidosis patients and a higher PM_LV_ratio than hypertensive and amyloidosis patients. Enlarged absolute papillary muscle area was evidenced in 21 (75%), and increased PM_LV_ratio was found in 22 (78%) of 28 Fabry patients. Combining these two parameters yields a sensitivity of 75% and specificity of 86% for diagnosing Fabry disease with LV hypertrophy. Only 10 of 73 non-Fabry patients (14%) (4 Friedreich, 1 amyloidosis, 5 hypertensive) showed an increased absolute papillary muscle area and PM_LV_ratio. In conclusion, this study confirmed the assumption that the prominent papillary muscle could be an echocardiographic marker for detection of Fabry patients with concentric LV hypertrophy.

Assessment of apical rocking: a new, integrative approach for selection of candidates for cardiac resynchronization therapy

AIMS

Current attempts of improving patient selection in cardiac resynchronization therapy (CRT) are mainly based on echocardiographic timing of myocardial velocity peaks. Regional myocardial function is neglected. Apical transverse motion (ATM) is a new parameter to quantify apical rocking as an integrative surrogate of both temporal and functional inhomogeneities within the left ventricle. In this study, we tested the predictive value of apical rocking for response to CRT.

METHODS AND RESULTS

Sixty-nine patients eligible for CRT were assessed by echocardiography before and 11 ± 5 months after pacemaker implantation. Response was defined as left ventricular (LV) end-systolic volume decrease >15%. Rocking was quantified (ATM) and visually assessed by four blinded readers. Predictive value for CRT response of both assessments was compared with conventional dyssynchrony parameters. ATM in the four-chamber view plane differentiated best between responders and non-responders (2.2 ± 1.5 vs. 0.06 ± 1.9 mm, P< 0.0001). Quantified ATM predicted reverse remodelling with a sensitivity, specificity, and accuracy of 75, 96, and 83% whereas visual rocking assessment resulted in 89, 75, and 83%, respectively. The accuracy of conventional parameters was significantly lower.

CONCLUSION

Apical rocking is a new marker to assess LV dyssynchrony and predict CRT response. It is superior to conventional parameters. Even its simple visual assessment may be sufficiently accurate in the clinical setting.

Longitudinal peak strain detects a smaller risk area than visual assessment of wall motion in acute myocardial infarction

BACKGROUND

Opening of an occluded infarct related artery reduces infarct size and improves survival in acute ST-elevation myocardial infarction (STEMI). In this study we performed tissue Doppler analysis (peak strain, displacement, mitral annular movement (MAM)) and compared with visual assessment for the study of the correlation of measurements of global, regional and segmental function with final infarct size and transmurality. In addition, myocardial risk area was determined and a prediction sought for the development of infarct transmurality >or=50%.

METHODS

Twenty six patients with STEMI submitted for primary percutaneous coronary intervention (PCI) were examined with echocardiography on the catheterization table. Four to eight weeks later repeat echocardiography was performed for reassessment of function and magnetic resonance imaging for the determination of final infarct size and transmurality.

RESULTS

On a global level, wall motion score index (WMSI), ejection fraction (EF), strain, and displacement all showed significant differences (p <or= 0.001, p <or= 0.001, p <or= 0.001 and p = 0.03) between the two study visits, but MAM did not (p = 0.17). On all levels (global, regional and segmental) and both pre- and post PCI, WMSI showed a higher correlation with scar transmurality compared to strain. We found that both strain and WMSI predicted the development of scar transmurality >or=50%, but strain added no significant information to that obtained with WMSI in a logistic regression analysis.

CONCLUSIONS

In patients with acute STEMI, WMSI, EF, strain, and displacement showed significant changes between the pre- and post PCI exam. In a ROC-analysis, strain had 64% sensitivity at 80% specificity and WMSI around 90% sensitivity at 80% specificity for the detection of scar with transmurality >or=50% at follow-up.

Baseline and follow-up assessment of regional left ventricular volume using 3-Dimensional echocardiography: comparison with cardiac magnetic resonance

The assessment of regional volumes is an option for analysis of the response of LV segments to interventions such as revascularization or cell therapy. We sought to compare regional volumes from 3D-echocardiography (3DE) with cardiac magnetic resonance (CMR) over follow-up. CMR regional volumes were assessed at baseline and after one year follow-up in 30 unselected patients (28 men, 65 +/- 11 years) presenting for evaluation of cardiac function with previous infarction. 3DE images were also gathered over 4 cardiac cycles and measurements were performed off-line. CMR images were obtained using a 1.5 Tesla scanner and measured offline by method of landmarks and by centre of mass. Regional volumes were measured at end-diastole (rEDV) and end-systole (rESV) and the change in volume was compared for each over follow-up. There was good correlation between 3DE and both CMR methods at baseline and follow-up. Changes in rEDV with 3DE vs CMR(L) were comparable (0.11 +/- 3 ml vs 0.12 +/- 3 ml, p = 0.94), as was change in CMR(M) (0.26 +/- 2 ml, p = 0.69). However the change in regional volume by 3DE and CMR(L) correlated poorly (r = 0.03, p = 0.68), as did change in 3DE vs CMR(M) (r = 0.04, p = 0.65). Similarly, changes in rESV with 3DE and CMR(L) were similar (0.27 +/- 2 ml vs 0.36 +/- 2 ml, p = 0.70), as was change in CMR(M) (0.05 +/- 1 ml, p = 0.31). Again, correlations between rESV by 3DE vs CMR(L) were poor (r = 0.03, p = 0.72), as well as 3DE vs CMR(M) (r = 0.07, p = 0.40). Although global 3DE volumes compare well with CMR volumes, new developments in image quality and automated software will be needed before changes in regional volumes can be reliably followed with 3DE.

Diagnostic capability and reproducibility of strain by Doppler and by speckle tracking in patients with acute myocardial infarction

OBJECTIVES

The objective of the present study was to investigate the ability of strain by Doppler and by speckle tracking echocardiography in the acute phase in patients with ST-segment elevation myocardial infarction (STEMI) to diagnose left ventricular (LV) infarct size. Furthermore, we wanted to study at which time during the cardiac cycle strain should be measured.

BACKGROUND

The assessment of regional myocardial dysfunction may be an important diagnostic tool in the evaluation of acute myocardial injury.

METHODS

Strain by Doppler and speckle tracking were assessed in the acute phase and after 10 days in 36 patients (61 +/- 11 years) with STEMI treated with thrombolysis. In a 16-segment model of the LV, peak systolic, end systolic, and peak negative strain were validated against the corresponding myocardial segments measured by contrast-enhanced cardiac magnetic resonance. The 16 segments were averaged to assess LV global longitudinal strain. In addition, 6 segments were analyzed from parasternal short-axis recordings at the papillary muscle level to assess circumferential strain. Reproducibility was tested in 20 patients.

RESULTS

The different segmental strain assessments separated significantly (p < 0.0001) between the different levels of infarct transmurality regardless of method, with better reproducibility for speckle strain. Circumferential strain separated better than longitudinal strain. With a cutoff value of -13.3% for segmental circumferential strain, sensitivity was 80% and specificity was 74% for prediction of transmural infarction. The LV global strain showed a good correlation with LV infarct size, with the best correlation for LV global peak systolic speckle strain (beta = 0.76, p < 0.0001).

CONCLUSIONS

On a segmental level, circumferential strain separated transmural from subendocardial necrosis better than longitudinal strain in the acute phase in patients with STEMI. Our findings suggest that in the acute phase in patients treated with thrombolysis, LV global peak systolic speckle strain should be the preferred method for predicting final LV infarct size.

Left ventricular systolic and diastolic dyssynchrony in coronary artery disease with preserved ejection fraction

The present study aims to evaluate LV (left ventricular) mechanical dyssynchrony in CAD (coronary artery disease) with preserved and depressed EF (ejection fraction). Echocardiography with TDI (tissue Doppler imaging) was performed in 311 consecutive CAD patients (94 had preserved EF > or =50% and 217 had depressed EF <50%) and 117 healthy subjects to determine LV systolic and diastolic dyssynchrony by measuring Ts-SD (S.D. of time to peak myocardial systolic velocity during the ejection period) and Te-SD (S.D. of time to peak myocardial early diastolic velocity during the filling period) respectively, using a six-basal/six-mid-segmental model. In CAD patients with preserved EF, both Ts-SD (32.2+/-17.3 compared with 17.7+/-8.6 ms; P<0.05) and Te-SD (26.2+/-13.6 compared with 20.3+/-8.1 ms; P<0.05) were significantly prolonged when compared with controls, although they were less prolonged than CAD patients with depressed EF (Ts-SD, 37.8+/-16.5 ms; and Te-SD, 36.0+/-23.9 ms; both P<0.005). Patients with preserved EF who had no prior MI (myocardial infarction) had Ts-SD (32.9+/-17.5 ms) and Te-SD (28.6+/-14.8 ms) prolonged to a similar extent (P=not significant) to those with prior MI (Ts-SD, 28.4+/-16.8 ms; and Te-SD, 25.5+/-15.0 ms). Patients with class III/IV angina or multi-vessel disease were associated with more severe mechanical dyssynchrony (P<0.05). Furthermore, the majority of patients with mechanical dyssynchrony had narrow QRS complexes in those with preserved EF. This is in contrast with patients with depressed EF in whom systolic and diastolic dyssynchrony were more commonly associated with wide QRS complexes. In conclusion, LV mechanical dyssynchrony is evident in CAD patients with preserved EF, although it was less prevalent than those with depressed EF. In addition, mechanical dyssynchrony occurred in CAD patients without prior MI and narrow QRS complexes.

Improved estimation and visualization of two-dimensional myocardial strain rate using MR velocity mapping

PURPOSE

To estimate regional myocardial strain rate, with reduced sensitivity to noise and velocities outside the region of interest, and provide a visualization of the spatial variation of the obtained tensor field within the myocardium.

MATERIALS AND METHODS

Myocardial velocities were measured using two-dimensional phase contrast velocity mapping. Velocity gradients were estimated using normalized convolution and the calculated 2D strain rate tensor field was visualized using a glyph representation. Validation utilized a numerical phantom with known strain rate distribution. Strain rate glyph visualizations were created for normal myocardium in both systole and diastole and compared to a patient with an anteroseptal infarction.

RESULTS

In the phantom study the strain rate calculated with normalized convolution showed a very good agreement with the analytic solution, while traditional methods for gradient estimation were shown to be sensitive to both noise and surrounding velocity data. Normal myocardium showed a homogenous strain rate distribution, while a heterogeneous strain rate can be clearly seen in the patient data.

CONCLUSION

The proposed approach for quantification and visualization of the regional myocardial strain rate can provide an objective measure of regional myocardial contraction and relaxation that may be valuable for the assessment of myocardial heart disease.

Standard values for real-time transthoracic three-dimensional echocardiographic dyssynchrony indexes in a normal population

BACKGROUND

There is a paucity of information describing the real-time 3-dimensional echocardiography (RT3DE) and dyssynchrony indexes (DIs) of a normal population. We evaluate the RT3DE DIs in a population with normal electrocardiograms and 2- and 3-dimensional echocardiographic analyses. This information is relevant for cardiac resynchronization therapy.

METHODS

We evaluated 131 healthy volunteers (73 were male, aged 46 +/- 14 years) who were referred for routine echocardiography; who presented normal cardiac structure on electrocardiography, 2-dimensional echocardiography, and RT3DE; and who had no history of cardiac diseases. We analyzed 3-dimensional left ventricular ejection fraction, left ventricle end-diastolic volume, left ventricle end-systolic volume, and left ventricular systolic DI% (6-, 12-, and 16-segment models). RT3DE data were analyzed by quantifying the statistical distribution (mean, median, standard deviation [SD], relative SD, coefficient of skewness, coefficient of kurtosis, Kolmogorov-Smirnov test, D'Agostino-Pearson test, percentiles, and 95% confidence interval).

RESULTS

Left ventricular ejection fraction ranged from 50% to 80% (66.1% +/- 7.1%); left ventricle end-diastolic volume ranged from 39.8 to 145 mL (79.1 +/- 24.9 mL); left ventricle end-systolic volume ranged from 12.9 to 66 mL (27 +/- 12.1 mL); 6-segment DI% ranged from 0.20% to 3.80% (1.21% +/- 0.66%), median: 1.06, relative SD: 0.5482, coefficient of skewness: 1.2620 (P < .0001), coefficient of Kurtosis: 1.9956 (P = .0039); percentile 2.5%: 0.2900, percentile 97.5%: 2.8300; 12-segment DI% ranged from 0.22% to 4.01% (1.29% +/- 0.71%), median: 1.14, relative SD: 0.95, coefficient of skewness: 1.1089 (P < .0001), coefficient of Kurtosis: 1.6372 (P = .0100), percentile 2.5%: 0.2850, percentile 97.5%: 3.0700; and 16-segment DI% ranged from 0.29% to 4.88% (1.59 +/- 0.99), median: 1.39, relative SD: 0.56, coefficient of skewness: 1.0792 (P < .0001), coefficient of Kurtosis: 0.9248 (P = .07), percentile 2.5%: 0.3750, percentile 97.5%: 3.750.

CONCLUSION

This study allows for the quantification of RT3DE DIs in normal subjects, providing a comparison for patients with heart failure who may be candidates for cardiac resynchronization therapy.

High frequency ultrasound imaging detects cardiac dyssynchrony in noninfarcted regions of the murine left ventricle late after reperfused myocardial infarction

Cardiac dyssynchrony in the left ventricles of murine hearts late (> or =28 d) after reperfused myocardial infarction (post-MI) was assessed using high frequency 30 MHz B-mode ultrasound imaging. Nine post-MI and six normal C57Bl/6 mice were studied in both short- and long-axis views. Regional time to peak displacement (T(peak_d)) and time to peak strain (T(peak_s)) were calculated in 36 sectors along the myocardial circumference; then their standard deviations (SD_T(peak_d) and SD_T(peak_s)) were computed among noninfarcted myocardial regions for each mouse and were compared between the normal and post-MI mouse groups with Student's t-test. The comparison revealed that SD_T(peak_d) and SD_T(peak_s) were significantly larger in the post-MI hearts than in the normal hearts. The displacement uniformity ratio was determined to be 0.97 +/- 0.01 and 0.85 +/- 0.07 for radial and circumferential displacements in the normal hearts, respectively; and 0.59 +/- 0.17 and 0.64 +/- 0.24 in the post-MI hearts. In conclusion, this high resolution ultrasound image tracking method provides for the detection of cardiac dyssynchrony in the noninfarcted regions in the murine left ventricles late after MI by identifying the temporal and spatial disparity of regional myocardial contraction.

Quantification of regional volume and systolic function of the left ventricle by real-time three-dimensional echocardiography

Real-time three-dimensional (3D) echocardiography (RT-3DE) provides a unique technique to evaluate left ventricular regional function in a 3D format. We aimed to explore whether the left ventricular segmental volume and systolic function is uniform and to establish normal values of volume and systolic function parameters of 16 regions in healthy subjects. RT-3DE was performed in 41 normal subjects and four-dimensional (4D)-left ventricle (LV) analysis software and a TomTec workstation were used to analyze data for regional end-diastolic volume (EDV(R)), regional end-systolic volume (ESV(R)), regional stroke volume (SV(R)), regional ejection fraction (EF(R)), ratio of SV(R) to global SV (SV(R/G)) and ratio of SV(R) to global EDV (EF(R/G)). All regional volume and systolic function parameters were not uniform among the left ventricular walls. They all increased in the order of inferior, posterior, lateral, septal, anterior and antero-septal walls with an increasing trend from the apical, middle to basal segments. The systolic function (EF(R), SV(R/G) and EF(R/G)) of the anterior and antero-septal walls was significantly higher than that of the lateral, inferior and posterior walls. And the intra- and interobserver variability for EDV(R), ESV(R), SV(R/G) and EF(R/G) ranged from 2.9% to 5.8%. In conclusion, the regional volume and systolic function of the left ventricle is not uniform and, therefore, a normal left ventricle cannot be regarded as a symmetric model for assessing the regional systolic function. This information may improve the accuracy of RT-3DE techniques in the assessment of the left ventricular regional function. (E-mail: zhangyun@sdu.edu.cn and yaogh@yahoo.com).

Strain rate imaging pre- and post-percutaneous coronary intervention: a potential role in the objective detection of ischaemia in exercise stress echocardiography

AIMS

To determine the feasibility of strain rate imaging (SRI) in the objective detection of exercise-induced ischaemia.

METHODS AND RESULTS

Sixteen patients undergoing elective percutaneous coronary intervention (PCI) underwent treadmill exercise stress echocardiography (ESE) pre- and post-PCI. Measurement of systolic SRI parameters was attempted in all myocardial segments at baseline, peak stress, and in recovery. Segments were divided into those supplied by target (Group 1) and non-target vessels (Group 2). Percutaneous coronary intervention was successful in all patients. In Group 1, there was no significant difference in post-systolic strain rate (SRps) at baseline or at peak stress but there was significantly greater SRps pre-PCI compared with post-PCI at 30 min into recovery (-0.37 +/- 0.53 vs. -0.07 +/- 0.44 s(-1), P = 0.004). There were similar findings with the SRps index [ratio of SRps:peak systolic strain rate (SRsys)]. Group 2 segments did not demonstrate any significant differences in SRI parameters pre- and post-PCI. At peak exercise pre-PCI, Group 1 segments had significantly delayed time to SRsys compared with Group 2 (0.12 +/- 0.05 vs. 0.09 +/- 0.05 s, P = 0.013), a difference that was abolished post-PCI.

CONCLUSION

This suggests a potential role for SRI in the objective detection of exercise-induced ischaemia by echocardiography at peak stress and during recovery at the time of improved image quality.

Comparison between dobutamine echocardiography and single-photon emission computed tomography for interpretive reproducibility

Interpretive variability of dobutamine stress echocardiography (DSE) and stress single-photon emission computed tomography (SPECT) has been previously investigated. However, no study has directly compared the variability of these techniques in the same patient population. We directly compared the interpretive reproducibility of DSE and stress SPECT in patients undergoing both types of pharmacologic stress imaging. Before discharge, simultaneous DSE and SPECT was performed in 56 patients early after a first acute myocardial infarction. Intra- and interobserver concordances were evaluated by exact agreement and kappa statistic. Intraclass coefficient of correlation was used to assess intra- and interobserver reproducibilities of segmental score analysis. Intraobserver agreement percentages in the identification of patients with ischemia were 98% for SPECT and 91% for DSE (p = NS) and kappa values were excellent (>0.80) for both techniques. Interobserver agreement was higher (p <0.01) for SPECT (96%) than for DSE (79%). Similarly, kappa value was excellent for SPECT (0.92) and only moderate for DSE (0.56). Finally, the intraclass coefficients of correlation for intra- and interobserver reproducibilities were higher for SPECT (0.98 and 0.97, respectively) than for DSE (0.80 and 0.71, respectively; p <0.001 for both). In conclusion, after uncomplicated acute myocardial infarction, stress SPECT imaging has a better interpretive reproducibility than DSE.