Left Ventricular Mechanics in Idiopathic Dilated Cardiomyopathy: Systolic-Diastolic Coupling and Torsion

Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023

Central Illustration : Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023 Proposal for including strain in the integrated diastolic function assessment algorithm, adapted from Nagueh et al.67 Am: mitral A-wave duration; Ap: reverse pulmonary A-wave duration; DD: diastolic dysfunction; LA: left atrium; LASr: LA strain reserve; LVGLS: left ventricular global longitudinal strain; TI: tricuspid insufficiency. Confirm concentric remodeling with LVGLS. In LVEF, mitral E wave deceleration time < 160 ms and pulmonary S-wave < D-wave are also parameters of increased filling pressure. This algorithm does not apply to patients with atrial fibrillation (AF), mitral annulus calcification, > mild mitral valve disease, left bundle branch block, paced rhythm, prosthetic valves, or severe primary pulmonary hypertension.

Automated segmentation of long and short axis DENSE cardiovascular magnetic resonance for myocardial strain analysis using spatio-temporal convolutional neural networks

BACKGROUND

Cine Displacement Encoding with Stimulated Echoes (DENSE) facilitates the quantification of myocardial deformation, by encoding tissue displacements in the cardiovascular magnetic resonance (CMR) image phase, from which myocardial strain can be estimated with high accuracy and reproducibility. Current methods for analyzing DENSE images still heavily rely on user input, making this process time-consuming and subject to inter-observer variability. The present study sought to develop a spatio-temporal deep learning model for segmentation of the left-ventricular (LV) myocardium, as spatial networks often fail due to contrast-related properties of DENSE images.

METHODS

2D + time nnU-Net-based models have been trained to segment the LV myocardium from DENSE magnitude data in short- and long-axis images. A dataset of 360 short-axis and 124 long-axis slices was used to train the networks, from a combination of healthy subjects and patients with various conditions (hypertrophic and dilated cardiomyopathy, myocardial infarction, myocarditis). Segmentation performance was evaluated using ground-truth manual labels, and a strain analysis using conventional methods was performed to assess strain agreement with manual segmentation. Additional validation was performed using an externally acquired dataset to compare the inter- and intra-scanner reproducibility with respect to conventional methods.

RESULTS

Spatio-temporal models gave consistent segmentation performance throughout the cine sequence, while 2D architectures often failed to segment end-diastolic frames due to the limited blood-to-myocardium contrast. Our models achieved a DICE score of 0.83 ± 0.05 and a Hausdorff distance of 4.0 ± 1.1 mm for short-axis segmentation, and 0.82 ± 0.03 and 7.9 ± 3.9 mm respectively for long-axis segmentations. Strain measurements obtained from automatically estimated myocardial contours showed good to excellent agreement with manual pipelines, and remained within the limits of inter-user variability estimated in previous studies.

CONCLUSION

Spatio-temporal deep learning shows increased robustness for the segmentation of cine DENSE images. It provides excellent agreement with manual segmentation for strain extraction. Deep learning will facilitate the analysis of DENSE data, bringing it one step closer to clinical routine.

Midwall Fibrosis and Cardiac Mechanics: Rigid Body Rotation Is a Novel Marker of Disease Severity in Pediatric Primary Dilated Cardiomyopathy

Background

Midwall fibrosis (MWF) detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) predicts adverse outcome in adults with dilated cardiomyopathy (DCM). Its relevance in children and adolescents is relatively unknown. Left ventricular (LV) strain, rotation and twist are important parameters of cardiac function; yet, their role in pediatric heart failure is understudied. This study aimed to evaluate MWF and cardiac mechanics in pediatric DCM.

Methods

Patients ≤21 years with primary DCM were prospectively enrolled and underwent standardized CMR including LGE. All participants were categorized according to the presence or absence of MWF (MWF+ vs. MWF–). Cardiac mechanics were assessed using CMR feature tracking. Impaired LV twist with apex and base rotating in the same direction was termed rigid body rotation (RBR).

Results

In total, 17 patients (median age 11.2 years) were included. MWF was present in seven patients (41%). Median N-terminal pro brain natriuretic peptide (NT-proBNP) was higher (5,959 vs. 242 pg/ml, p = 0.887) and LV ejection fraction (LVEF) lower (28 vs. 39%, p = 0.536) in MWF+ vs. MWF– patients, yet differences were not statistically significant. MWF+ patients had reduced global longitudinal (GLS), circumferential (GCS) and radial strain (GRS), again without statistical significance (p = 0.713, 0.492 and 1.000, respectively). A relationship between MWF and adverse outcome was not seen (p = 0.637). RBR was more common in MWF+ (67 vs. 50%), and was associated with the occurrence of adverse events (p = 0.041). Patients with RBR more frequently were in higher New York Heart Association classes (p = 0.035), had elevated NT-proBNP levels (p = 0.002) and higher need for catecholamines (p = 0.001). RBR was related to reduced GLS (p = 0.008), GCS (p = 0.031), GRS (p = 0.012), LV twist (p = 0.008), peak apical rotation (p < 0.001), and LVEF (p = 0.001), elevated LV end-diastolic volume (p = 0.023) and LV end-systolic volume (p = 0.003), and lower right ventricular stroke volume (p = 0.023).

Conclusions

MWF was common, but failed to predict heart failure. RBR was associated with clinical and biventricular functional signs of heart failure as well as the occurrence of adverse events. Our findings suggest that RBR may predict outcomes and may serve as a novel marker of disease severity in pediatric DCM.

Clinical Trial Registration:https://clinicaltrials.gov/, identifier: NCT03572569.

Quantitative assessment of left ventricular longitudinal function and myocardial deformation in Duchenne muscular dystrophy patients

Background

Duchenne muscular dystrophy (DMD) manifests in males mainly by skeletal muscle impairment, but also by cardiac dysfunction. The assessment of the early phases of cardiac involvement using echocardiography is often very difficult to perform in these patients. The aim of the study was to use cardiac magnetic resonance (CMR) strain analysis and mitral annular plane systolic excursion (MAPSE) in the detection of early left ventricular (LV) dysfunction in DMD patients.

Methods and results

In total, 51 male DMD patients and 18 matched controls were examined by CMR. MAPSE measurement and functional analysis using feature tracking (FT) were performed. Three groups of patients were evaluated: A/ patients with LGE and LV EF < 50% (n = 8), B/ patients with LGE and LVEF ≥ 50% (n = 13), and C/ patients without LGE and LVEF ≥ 50% (n = 30). MAPSE and global LV strains of the 3 DMD groups were compared to controls (n = 18).

Groups A and B had significantly reduced values of MAPSE, global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) in comparison to controls (p < 0.05). The values of MAPSE (11.6 ± 1.9 v 13.7 ± 2.7 mm) and GCS (− 26.2 ± 4.2 v − 30.0 ± 5.1%) were significantly reduced in group C compared to the controls (p < 0.05).

Conclusion

DMD patients had decreased LV systolic function measured by MAPSE and global LV strain even in the case of normal LV EF and the absence of LGE. FT and MAPSE measurement provide sensitive assessment of early cardiac involvement in DMD patients.

Left Ventricular Strain and Rotation in Patients with Dilated Cardiomyopathy and Severe Systolic Dysfunction

INTRODUCTION

In dilated cardiomyopathy (DCM) left ventricular (LV) strain and twist are significantly decreased. However, the rate of attenuation has not been investigated well in patients with varying degrees of systolic dysfunction.

AIM

The present study aimed to investigate the relationship between LV deformational and rotational mechanics and conventional and tissue Doppler imaging (TDI) parameters, and to search for a constellation of findings distinguishing patients with severe systolic dysfunction (SSD) in DCM.

METHODS

Fifty-two patients with heart failure NYHA class III-IV and ejection fraction (EF) ≤45% were prospectively enrolled (mean age 61.8 ± 13.4 years; 36 males, 69%). Severe systolic LV dysfunction was considered as EF <30%. Echocardiography with 2D-speckle tracking analysis was performed.

RESULTS

The relationships of global longitudinal strain (GLS) with EF, circumferential strain at mid-level (CSmid), and systolic medial mitral annulus velocity were strong (r = -0.53, 0.67, and -0.56, respectively, p < 0.0001 for all). A good correlation was found between CSmid and EF (r = -0.50, p < 0.0001). There were weak correlations between basal endocardial rotation (BRendo) and EF and CSmid. Multiple regression analysis found GLS (p < 0.0001) and BRendo (p = 0.04) to be predictors of the change of EF. In ROC curve analysis, the cut-off values of GLS -7.2% (AUC 0.81, p < 0.0001), CSmid -7.5% (AUC 0.76, p = 0.002), and BRendo -2.43° (AUC 0.68, p = 0.03) identified SSD.

CONCLUSIONS

Parameters of LV mechanics were related to conventional and TDI systolic parameters in patients with DCM. The degree of alterations of LV longitudinal and circumferential deformation and basal rotation may identify patients with SSD and a higher risk, and may help in therapeutic decision making.

Role of Speckle Tracking Echocardiography in Dilated Cardiomyopathy: A Review

Dilated cardiomyopathy (DCM) is an important cause of the heart failure. Timely diagnosis and optimal management decrease morbidity and mortality in heart failure patients. Although transthoracic echocardiography is used as the diagnostic test of choice in these patients, new modalities like speckle tracking echocardiography (STE) have promising results in diagnosing these patients in the earlier course of the disease. Advancements in cardiac imaging are expected as more clinical studies on the role of STE in different cardiac diseases that emerge. In this review article, we will discuss the basics of STE and its role in diagnosing DCM.

Forgotten Right Ventricle in Pediatric Dilated Cardiomyopathy

To evaluate the right ventricular (RV) function in relation to that of the left ventricle (LV) in patients with dilated cardiomyopathy (DCM). Echocardiographic examination was done using tissue Doppler imaging (TDI) and two-dimensional speckle tracking echocardiography (2D-STE) for 32 pediatric patients with DCM comparing them to another 32 normal matched controls. The global longitudinal strain (GLS) derived from 2D-STE was used to reflect the LV systolic function. Tricuspid annular plan systolic excursion (TAPSE) and the following RV TDI derived indexes: peak systolic velocity (S'), peak early diastolic velocity E', peak late diastolic velocity A', isovolumic acceleration (IVA) and myocardial performance index (MPI) were measured. RV had significant systolic and diastolic dysfunction; TAPSE, S' velocity, IVA, peak early diastolic velocity (E') and peak early diastolic velocity/peak late diastolic velocity (E'/A') ratio were significantly decreased while MPI was significantly prolonged compared to controls. Moreover, TAPSE, S', IVA, E', E'/A' and RV MPI were significantly correlated to LV GLS. For prediction of LV dysfunction among patients, the area under the receiver operating characteristic curve was 0.98 for RV MPI, 0.906 for RV IVA. For identifying severe LV dysfunction; RV MPI  > 0.29 had 100% sensitivity and 93.7% specificity, while the RV IVA  ≤ 3 had 84.4% sensitivity and 90.6% specificity. In pediatric patients with DCM the RV systolic and diastolic functions are affected beside the LV dysfunction. Non-conventional echocardiographic evaluation of RV function is recommended in among this cohort.

Myocardial deformation pattern in left ventricular non-compaction: Comparison with dilated cardiomyopathy

INTRODUCTION

Left ventricular (LV) systolic dysfunction is the most frequent initial presentation of patient with LV noncompaction (NC). Our objectives were to evaluate myocardial contraction properties in patients with LVNC and the relationship of non-compacted segments with the degree of global and regional systolic deformation.

METHODS

We included 50 LVNC with an echocardiography and speckle imaging calculation of peak longitudinal strain (PLS). Each of the 16 LV myocardial segments was defined as NC (ratio NC/compacted layer > 2), borderline (NC/C 0-2) and compacted (NC/C = 0). Basal, median and apical strain values were calculated as the average of segmental strain values. For comparison a group of 50 patients with dilated cardiomyopathy (DCM) underwent the same measurements.

RESULTS

There was no statistical difference between the 2 groups for any conventional LV systolic parameters. A characteristic deformation pattern was observed in LVNC with higher strain values in the LV apical segments (- 12.8 ± 5.9 vs - 10.7 ± 5.7) and an apical-basal ratio (1.52 ± 0.73 vs 1.12 ± 0.42; p < 0.001). There was no correlation between LV function and the degree of NC. Among 726 segments, compacta thickness was thinner in NC vs C segments (6.4 ± 1.4 vs 7.7 ± 1.8 mm; p < 0.05). There was no difference in WMS but regional strain values were significantly higher in NC compared to C segments (- 13.1 ± 6.1 vs - 10.2 ± 6.3; p < 0.05).

CONCLUSIONS

Compared to DCM, LVNC presented with relatively preserved apical deformation as compared to basal segments. Lower regional deformation values in compacted segments confirm the concept that LVNC is a phenotypic marker of an underlying diffuse cardiomyopathy involving both C and NC myocardium.

Feasibility of radial and circumferential strain analysis using 2D speckle tracking echocardiography in cats

The purpose of the present study is to investigate the feasibility of strain analysis using speckle tracking echocardiography (STE) in cats and to evaluate STE variables in cats with hypertrophic cardiomyopathy (HCM). Sixteen clinically healthy cats and 17 cats with HCM were used. Radial and circumferential strain and strain rate variables in healthy cats were measured using STE to assess the feasibility. Comparisons of global strain and strain variables between healthy cats and cats with HCM were performed. Segmental assessments of left ventricle (LV) wall for strain and strain rate variables in cats with HCM were also performed. As a result, technically adequate images were obtained in 97.6% of the segments for STE analysis. Sedation using buprenorphine and acepromazine did not affect any global strain nor strain rate variable. In LV segments of cats with HCM, reduced segmental radial strain and strain rate variables had significantly related with segmental LV hypertrophy. It is concluded that STE analysis using short axis images of LV appeared to be clinically feasible in cats, having the possibility to be useful for detecting myocardial dysfunctions in cats with diseased heart.

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.

Effect of through-plane motion on left ventricular rotation: a study using slice-following harmonic phase imaging

Noninvasive quantification of regional left ventricular rotation may improve understanding of cardiac function. Current methods used to quantify rotation typically acquire data on a set of prescribed short-axis slices, neglecting effects due to through-plane myocardial motion. We combine principles of slice-following tagged imaging with harmonic phase analysis methods to account for through-plane motion in regional rotation measurements. We compare rotation and torsion measurements obtained using our method to those obtained from imaging datasets acquired without slice-following. Our results in normal volunteers demonstrate differences in the general trends of average and regional rotation-time plots in midbasal slices and the rotation versus circumferential strain loops. We observe substantial errors in measured peak average rotation of the order of 58% for basal slices (due to change in the pattern of the curve), -6.6% for midventricular slices, and -8.5% for apical slices; and an average error in base-to-apex torsion of 19% when through-plane motion is not considered. This study concludes that due to an inherent base-to-apex gradient in rotation that exists in the left ventricular, accounting for through-plane motion is critical to the accuracy of left ventricular rotation quantification.

Variability of post-exercise pulmonary capillary wedge pressure recovery. Implications for noninvasive echocardiographic diagnostics

AIM

The aim of our study was to assess the course of immediate post-exercise pulmonary capillary wedge pressure (PCWP) changes to identify the optimal time window for the noninvasive diagnostics of exercise-induced PCWP elevation.

METHODS AND RESULTS

Seventy-one patients at risk of heart failure with normal left ventricular ejection fraction underwent simultaneous exercise echocardiography and right heart catheterization. The ratio of early left ventricular filling velocity (E) to early diastolic mitral annular velocity (e') was used to predict noninvasively exercise-induced PCWP elevation. Fifty-one patients had exercise-induced PCWP elevation ≥ 8 mmHg and reached peak exercise PCWP ≥ 20 mmHg. Rapid post-exercise recovery of PCWP within 2 min was achieved in 18 (35.3%) patients. Intermediate post-exercise PCWP recovery at 3 and 4 min was found in 16 (31.4%) patients while late post-exercise PCWP recovery (≥ 5 min) was achieved in 17 (33.3%) patients.

CONCLUSION

The course of post-exercise PCWP recovery is highly variable, and a significant proportion of patients have only a brief period (≤ 2 min) of exercise-induced PCWP elevation. This fact should be taken into account in noninvasive assessment of exercise-induced PCWP.

Normal ranges of left ventricular strain: a meta-analysis

BACKGROUND

The definition of normal values of left ventricular global longitudinal strain (GLS), global circumferential strain, and global radial strain is of critical importance to the clinical application of this modality. The investigators performed a meta-analysis of normal ranges and sought to identify factors that contribute to reported variations.

METHODS

MEDLINE, Embase, and the Cochrane Library database were searched through August 2011 using the key terms "strain," "speckle tracking," "left ventricle," and "echocardiography" and related phrases. Studies were included if the articles reported left ventricular strain using two-dimensional speckle-tracking echocardiography in healthy normal subjects, either in the control group or as a primary objective of the study. Data were combined using a random-effects model, and effects of demographic, hemodynamic, and equipment variables were sought in a meta-regression.

RESULTS

The search identified 2,597 subjects from 24 studies. Reported normal values of GLS varied from -15.9% to -22.1% (mean, -19.7%; 95% CI, -20.4% to -18.9%). Normal global circumferential strain varied from -20.9% to -27.8% (mean, -23.3%; 95% CI, -24.6% to -22.1%). Global radial strain ranged from 35.1% to 59.0% (mean, 47.3%; 95% CI, 43.6% to 51.0%). There was significant between-study heterogeneity and inconsistency. The source of variation was sought between studies using meta-regression. Blood pressure, but not age, gender, frame rate, or equipment, was associated with variation in normal GLS values.

CONCLUSIONS

The narrowest confidence intervals from this meta-analysis were for GLS and global circumferential strain, but individual studies have shown a broad range of strain in apparently normal subjects. Variations between different normal ranges seem to be associated with differences in systolic blood pressure, emphasizing that this should be considered in the interpretation of strain.

The role of 3D wall motion tracking in heart failure

Heart failure is a major health problem in developed countries and a growing one in developing countries. Cardiac remodeling in heart failure affects myocardial mechanics, which requires comprehensive evaluation in three dimensions. The novel technique of 3D wall motion tracking applies speckle tracking technology to full volume, 3D echocardiographic datasets. Quantification of conventional and novel left ventricular (LV) parameters including volumes, ejection fraction, global and regional 3D strain, endocardial area strain, twist, and dyssynchrony, and identification of the site of latest mechanical activation are feasible on the basis of a single acquisition of a full-volume dataset. Clinical applications of 3D wall motion tracking include the assessment of global and regional LV performance in ischemic and nonischemic heart diseases, evaluation of mechanics in cardiomyopathies and congenital heart disease, potential selection of patients for cardiac resynchronization therapy and prediction of their response, and detection of subclinical cardiac dysfunction in diseases with likelihood of progression to heart failure. Technological advances with improvement in spatial and temporal resolution of this novel imaging modality are expected. Although 3D wall motion tracking is still in its infancy, this method has begun to provide new insights into LV mechanics and has already found clinical applications. Future developments in 3D assessment of right ventricular and myocardial layer-specific mechanics are awaited.

Loss of left ventricular torsion as the predominant mechanism of left ventricular systolic dysfunction in a patient with tubercular cardiomyopathy

Pericarditis is the commonest form of cardiac involvement in tuberculosis whereas myocardial involvement is exceedingly rare. We hereby report a patient who presented with cardiac tuberculosis manifesting as predominantly right-sided cardiomyopathy. In addition to being a very rare clinical presentation, this case provided an interesting insight into the left ventricular (LV) myocardial mechanics. The patient had nearly preserved contractile function of the LV myocardium (except for segmental abnormalities in circumferential strain) but had marked impairment of torsion resulting in LV systolic dysfunction. Such disproportionate loss of LV torsion leading to LV systolic dysfunction has not been previously described on echocardiography. These myocardial mechanical abnormalities almost completely recovered with adequate antitubercular treatment. Thus, this case proved to be a unique demonstration of the significant, independent role played by torsion in maintenance of normal LV systolic function.

Heart disease and left ventricular rotation - a systematic review and quantitative summary

Background

Left ventricular (LV) rotation is increasingly examined in those with heart disease. The available evidence measuring LV rotation in those with heart diseases has not been systematically reviewed.

Methods

To review systematically the evidence measuring LV rotational changes in various heart diseases compared to healthy controls, literature searches were conducted for appropriate articles using several electronic databases (e.g., MEDLINE, EMBASE). All randomized-controlled trials, prospective cohort and case–controlled studies that assessed LV rotation in relation to various heart conditions were included. Three independent reviewers evaluated each investigation’s quality using validated scales. Results were tabulated and levels of evidence assigned.

Results

A total of 1,782 studies were found through the systematic literature search. Upon review of the articles, 47 were included. The articles were separated into those investigating changes in LV rotation in participants with: aortic stenosis, myocardial infarction, hypertrophic cardiomyopathy, dilated cardiomyopathy, non-compaction, restrictive cardiomyopathy/ constrictive pericarditis, heart failure, diastolic dysfunction, heart transplant, implanted pacemaker, coronary artery disease and cardiovascular disease risk factors. Evidence showing changes in LV rotation due to various types of heart disease was supported by evidence with limited to moderate methodological quality.

Conclusions

Despite a relatively low quality and volume of evidence, the literature consistently shows that heart disease leads to marked changes in LV rotation, while rotational systolic-diastolic coupling is preserved. No prognostic information exists on the potential value of rotational measures of LV function. The literature suggests that measures of LV rotation may aid in diagnosing subclinical aortic stenosis and diastolic dysfunction.

Subclinical myocardial dysfunction in patients with reverse-remodeled dilated cardiomyopathy

BACKGROUND

The aim of this study was to test the hypothesis that patients with reverse-remodeled dilated cardiomyopathy (DCM), whose ejection fractions (EFs) were normalized after optimal pharmacologic therapy, had subclinical myocardial dysfunction.

METHODS

Thirty-two patients with reverse-remodeled DCM, defined as having an initial EF ≤ 35%, which then recovered to ≥50% after optimal pharmacologic therapy, and 11 normal controls with preserved EFs were retrospectively studied. Averaged peak systolic and early diastolic radial, circumferential, and longitudinal speckle-tracking strain rates were assessed from an 18-segment left ventricular model. Similarly, averaged peak systolic radial, circumferential, and longitudinal speckle-tracking strain was obtained.

RESULTS

Peak systolic and early diastolic longitudinal strain rates, peak systolic and early diastolic circumferential strain rates, and peak circumferential and longitudinal strain in patients with reverse-remodeled DCM were significantly lower than those in normal controls, but peak systolic and early diastolic radial strain rates and peak radial strain in patients with reverse-remodeled DCM were similar to those in normal controls. Isometric handgrip stress testing showed a significant decrease in EF from 56 ± 5% to 51 ± 5% (P < .001). Of note, the increase of afterload resulting from isometric handgrip stress testing was associated with a decrease in peak systolic circumferential and longitudinal strain rates and peak circumferential strain in patients with reverse-remodeled DCM.

CONCLUSIONS

The circumferential and longitudinal myocardial function of patients with reverse-remodeled DCM is lower compared with that of normal controls with preserved EFs. Furthermore, the increase in afterload was associated with the decrease in circumferential and longitudinal myocardial systolic function. These findings suggest that in treated patients with DCM with reverse remodeling, left ventricular mechanics may not be normal, even when EFs are normal.

Two-dimensional speckle-tracking echocardiography reveals systolic abnormalities in granulomatosis with polyangiitis (Wegener's)

BACKGROUND

Two-dimensional speckle-tracking echocardiography (STE) is a novel technique providing accurate assessment of myocardial function. However, its value in granulomatosis with polyangiitis (Wegener's) (WG) has not been studied.

OBJECTIVE

To assess the presence and frequency of systolic left ventricular (LV) dysfunction using STE and to determine incremental value of STE over standard echocardiography to detect myocardial abnormalities in WG.

METHODS

Twenty-two WG patients (11 males, 11 females, mean age 46.8 ± 12.3 years) and 22 sex- and age-matched healthy subjects underwent standard and STE. Global longitudinal, circumferential, and rotational deformation parameters were calculated.

RESULTS

All patients had LV ejection fraction (EF) >50%. LVEF was 65.0 ± 7.5% and LV end-diastolic volume index 44.8 ± 11.8 mL/m(2) . Regional LV wall motion abnormalities were found in 7 (32%), while abnormal global STE determined systolic dysfunction in 16 (73%) subjects (P = 0.008). Global longitudinal, circumferential and radial peak-systolic deformational parameters (strain or strain rate) were decreased in 11 (50%), 9 (41%), and 3 (14%) patients (P = 0.02), respectively. Comparing patients with abnormal and normal STE derived global systolic function, the former had higher cumulative disease extent index (10.6 ± 3.0 vs 7.5 ± 1.8; P = 0.03) and vasculitis damage index (7.9 ± 1.9 vs 6.0 ± 1.7; P = 0.04).

CONCLUSIONS

Despite normal LVEF the global systolic LV abnormalities detected by STE are common in WG. They correspond to the extent and severity of WG and are more frequent than regional wall motion abnormalities in standard echocardiography.

Risk assessment of ventricular arrhythmias in patients with nonischemic dilated cardiomyopathy by strain echocardiography

BACKGROUND

Indications for prophylactic implantable cardioverter-defibrillator implantation in patients with nonischemic dilated cardiomyopathy (DCM) are based on left ventricular (LV) ejection fraction (LVEF), although LVEF has limited ability to predict arrhythmias. It has recently been shown that strain echocardiography can predict ventricular arrhythmias in patients after myocardial infarction. The aim of this study was to evaluate whether strain echocardiography may help in the risk stratification of ventricular arrhythmias in patients with DCM.

METHODS

Ninety-four patients with nonischemic DCM were prospectively included. By speckle-tracking strain echocardiography, global longitudinal strain was calculated as the average of peak longitudinal strain from a 16-segment LV model. The time interval from electrocardiographic peak R to peak negative strain was assessed in each LV segment. Mechanical dispersion was defined as the standard deviation of time to peak negative strain from 16 LV segments.

RESULTS

After a median of 22 months of follow-up (range, 1-46 months), 12 patients (13%) had experienced arrhythmic events, defined as sustained ventricular tachycardia or cardiac arrest. LVEF and global longitudinal strain were reduced in patients with DCM with arrhythmic events compared with those without (28 ± 10% vs 38 ± 13%, P = .01, and -6.4 ± 3.3% vs -12.3 ± 5.2%, P < .001, respectively). Global longitudinal strain showed greater area under the curve than LVEF to identify arrhythmic events in receiver operating characteristic curve analyses (P = .05). Patients with arrhythmic events had increased mechanical dispersion (98 ± 43 vs 56 ± 18 ms, P < .001). Mechanical dispersion predicted arrhythmias independently of LVEF (hazard ratio, 1.28; 95% confidence interval, 1.11-1.49; P = .001).

CONCLUSIONS

Global longitudinal strain is a promising marker of arrhythmias. Mechanical dispersion predicted arrhythmic events in patients with DCM independently of LVEF. Strain echocardiography may help in the risk stratification of patients with DCM not fulfilling current implantable cardioverter-defibrillator indications.

Preliminary clinical study of left ventricular myocardial strain in patients with non-ischemic dilated cardiomyopathy by three-dimensional speckle tracking imaging

Background

Non-ischemic dilated cardiomyopathy (DCM) is the most common cardiomyopathy worldwide, with significant mortality. Correct evaluation of the patient's myocardial function has important clinical significance in the diagnosis, therapeutic effect assessment and prognosis in non-ischemic DCM patients. This study evaluated the feasibility of three-dimensional speckle tracking imaging (3D-STE) for assessment of the left ventricular myocardial strain in patients with non-ischemic dilated cardiomyopathy (DCM).

Methods

Apical full-volume images were acquired from 65 patients with non-ischemic DCM (DCM group) and 59 age-matched normal controls (NC group), respectively. The following parameters were measured by 3D-STE: the peak systolic radial strain (RS), circumferential strain (CS), longitudinal strain (LS) of each segment. Then all the parameters were compared between the two groups.

Results

The peak systolic strain in different planes had certain regularities in normal groups, radial strain (RS) was the largest in the mid region, the smallest in the apical region, while circumferential strain (CS) and longitudinal strain (LS) increased from the basal to the apical region. In contrast, the regularity could not be applied to the DCM group. RS, CS, LS were significantly decreased in DCM group as compared with NC group (P < 0.001 for all). The interobserver, intraobserver and test-retest reliability were acceptable.

Conclusions

3D-STE is a reliable tool for evaluation of left ventricular myocardial strain in patients with non-ischemic DCM, with huge advantage in clinical application.

Fourier analysis of STimulated echoes (FAST) for the quantitative analysis of left ventricular twist

PURPOSE

To validate a novel method for the rapid and facile quantification of left ventricular (LV) twist from tagged magnetic resonance images and demonstrate the potential clinical utility in a series of 20 healthy volunteers.

MATERIALS AND METHODS

Cardiac magnetic resonance imaging (MRI) short-axis images were acquired with tissue tagging in 20 healthy subjects and six canines. The tagged images were processed using a novel Fourier Analysis of the STimulated echoes (FAST) method, which uses a series of Fourier-space operations to measure LV twist with limited user interaction. A subset of eight healthy subjects and the canine data were compared to results from previously validated "gold standard" software (FindTags). Interobserver and intraobserver coefficients of variation (CV(INTER) and CV(INTRA) ), linear regression, and Bland-Altman analyses were used to assess agreement between observers and methods.

RESULTS

CV(INTRA) for peak systolic twist (2.9% and 2.6%) and CV(INTER) (4.3% and 4.2%) were all small. Linear regression analysis of the FAST and FindTags twist values indicated very good agreement in healthy subjects (R = 0.91) and in canines (R = 0.95). Bland-Altman comparison of the FAST and FindTags twist results indicated excellent agreement in healthy subjects (bias of -0.5°, 95% confidence intervals (-4.3°, 4.3°)) and canines (bias of 0.2°, 95% confidence intervals (-2.7°, 3.1°)). Peak systolic twist in healthy subjects averaged 10.5 ± 1.9° degrees.

CONCLUSION

The FAST method for quantifying LV twist produces results that are not significantly different from the current "gold standard" in a fraction of the user interaction time and has demonstrated feasibility in human subjects.

The role of exercise echocardiography in the diagnostics of heart failure with normal left ventricular ejection fraction

AIMS

Few data are available on the exercise-induced abnormalities of myocardial function in patients with exertional dyspnoea and normal left ventricular ejection fraction (LV EF). The main aims of this study were to determine the prevalence of isolated exercise-induced heart failure with normal ejection fraction (HFNEF) and to assess whether disturbances in LV or right ventricular longitudinal systolic function are associated with the diagnosis of HFNEF.

METHODS AND RESULTS

Eighty-four patients with exertional dyspnoea and normal LV EF and 14 healthy controls underwent spirometry, NT-proBNP plasma analysis, and exercise echocardiography. Doppler LV inflow and tissue mitral and tricuspid annular velocities were analysed at rest and immediately after the termination of exercise. Of the 30 patients with the evidence of HFNEF, 6 (20%) patients had only isolated exercise-induced HFNEF. When compared with the remaining patients, those with HFNEF had a significantly lower resting and exercise peak mitral annular systolic velocity (Sa) and the mitral annular velocity during atrial contraction, lower exercise peak mitral annular velocity at early diastole, and lower exercise peak systolic velocity of tricuspid annular motion. The multivariate logistic regression analysis including both parameters standardly defining HFNEF and the new Doppler variables potentially associated with the diagnosis of HFNEF revealed that NT-proBNP, LV mass index, left atrial volume index, and Sa significantly and independently predict the diagnosis of HFNEF.

CONCLUSION

A significant proportion of patients require exercise to diagnose HFNEF. Sa appears to be a significant independent predictor of HFNEF, which may increase the diagnostic value of models utilizing the variables recommended by the European Society of Cardiology guidelines.

Assessment of left ventricular regional function in affected and carrier dogs with Duchenne muscular dystrophy using speckle tracking echocardiography

Background

Two-dimensional speckle tracking echocardiography (STE) is a relatively new method to detect regional myocardial dysfunction. To assess left ventricular (LV) regional myocardial dysfunction using STE in Duchenne muscular dystrophy model dogs (CXMD_J) without overt clinical signs of heart failure.

Methods

Six affected dogs, 8 carrier dogs with CXMD_J, and 8 control dogs were used. Conventional echocardiography, systolic and diastolic function by Doppler echocardiography, tissue Doppler imaging (TDI), and strain indices using STE, were assessed and compared among the 3 groups.

Results

Significant differences were seen in body weight, transmitral E wave and E' wave derived from TDI among the 3 groups. Although no significant difference was observed in any global strain indices, in segmental analysis, the peak radial strain rate during early diastole in posterior segment at chordae the tendineae level showed significant differences among the 3 groups.

Conclusions

The myocardial strain rate by STE served to detect the impaired cardiac diastolic function in CXMD_J without any obvious LV dilation or clinical signs. The radial strain rate may be a useful parameter to detect early myocardial impairment in CXMD_J.

Systolic-diastolic coupling of myocardial deformation of the left ventricle in children with left ventricular noncompaction

Disruption of the myocardial architecture in left ventricular noncompaction (LVNC) may alter myocardial deformation. We evaluated LV myocardial deformation and tested the hypothesis that tight systolic-diastolic coupling occurs in LVNC. Longitudinal and circumferential strain and strain rates (SRs) as determined by speckle tracking echocardiography in nine children aged 5.6 ± 5.5 years was compared with those in nine controls. Left ventricular systolic myocardial deformation parameters were correlated with ejection fraction and indices of diastolic deformation. Compared with controls, patients had lower global LV systolic longitudinal strain (P = 0.008), systolic SR (P = 0.05) and early diastolic SR (P < 0.001). Similarly, LV systolic circumferential strain (base, P = 0.04; papillary muscle level, P = 0.01; apex, P = 0.04), systolic SR (base, P = 0.04) and early diastolic SR (papillary muscle level, P = 0.004, apex, P = 0.02) were lower in patients than in controls. Among patients, the LV ejection fraction correlated with global longitudinal systolic strain and SR and circumferential systolic strain and SR at all levels (all P < 0.05). Positive correlations existed between early diastolic and systolic SRs in corresponding dimensions (longitudinal r = 0.80, P = 0.01; circumferential at base, r = 0.91, P = 0.001; papillary muscle level, r = 0.96, P < 0.001; apex r = 0.98, P = <0.001). In conclusion, LV myocardial deformation is reduced in the longitudinal and circumferential dimensions and manifests tight systolic-diastolic coupling in children with LVNC.

Assessment of myocardial mechanics using speckle tracking echocardiography: fundamentals and clinical applications

The authors summarize the recent developments in speckle-tracking echocardiography (STE), a relatively new technique that can be used in conjunction with two-dimensional or three-dimensional echocardiography for resolving the multidirectional components of left ventricular (LV) deformation. The tracking system is based on grayscale B-mode images and is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation. The integration of STE with real-time cardiac ultrasound imaging overcomes some of the limitations of previous work in the field and has the potential to provide a unified framework to more accurately quantify the regional and global function of the left ventricle. STE holds promise to reduce interobserver and intraobserver variability in assessing regional LV function and to improve patient care while reducing health care costs through the early identification of subclinical disease. Following a brief overview of the approach, the authors pool the initial observations from clinical studies on the development, validation, merits, and limitations of STE.