Normal range of myocardial layer-specific strain using two-dimensional speckle tracking echocardiography

Echocardiographic Assessment of Cardiac Remodeling According to Obesity Class

Evidence supports the existence of cardiac remodeling in obesity; however, no standard diagnostic criteria has been proposed or validated. This study aimed to identify echocardiographic features of cardiac remodeling according to obesity class and assess the effect of nonsurgical weight loss on cardiac structure and function. A total of 120 patients were divided according to their obesity class (group 1: body mass index [BMI] 18.5 to 24.9, group 2: 25 to 29.9, group 3: 30 to 39.9, and group 4: >40) and underwent cross-sectional transthoracic echocardiography. Echocardiographic parameters of cardiac chamber quantification and function were compared among the 4 groups. Echocardiographic parameters were compared before and after nonsurgical weight loss in a subgroup of patients. Overall, there was an incremental increase in left ventricular (LV), left atrial (LA), and right ventricular dimensions, LV mass (LVM), and LV stroke volume (all p <0.0001) across the obesity classes. There was no significant difference in LV ejection fraction or right ventricular systolic function, as assessed by tricuspid annular plane systolic excursion; however, there was a significant decrease in global longitudinal strain (BMI 18.5 to 24.9: 22.8 ± 1.7%, BMI 25 to 29.9: 22.0 ± 1.4%, BMI 30 to 39.9: 20.8 ± 1.1%, BMI >40: 20.6 ± 1.3%, p <0.0001) and LA strain (BMI 18.5 to 24.9: 37.7 ± 2.3%, BMI 25 to 29.9: 32.8 ± 2.1%, BMI 30 to 39.9: 31.5 ± 1.8%, BMI >40: 29.0 ± 2.8%, p <0.0001). Allometric height-indexed LV and LA dimensions increased with increasing BMI class (p <0.0001). Echocardiographic parameters did not change significantly after nonsurgical weight loss. In conclusion, echocardiographic features can be described according to obesity class. Allometric height indexation may better reflect cardiac remodeling in obesity than body surface area indexation. Nonsurgical weight loss was not associated with significant changes in cardiac chamber dimensions and function.

Layer-Specific Strain Analysis in Patients with Dilated Cardiomyopathy

BACKGROUND/OBJECTIVES

This study aimed to evaluate layer-specific strain according to etiology and assess whether subtle changes in longitudinal and circumferential layer strain are involved in predicting cardiac mortality during a two-year follow-up in patients with dilated cardiomyopathy admitted with heart failure decompensation.

METHODS

97 patients with dilated cardiomyopathy and a left ventricle ejection fraction ≤ 40% were recruited, 51 with ischemic and 46 with nonischemic etiologies. Conventional and two-dimensional speckle-tracking echocardiography (2D-STE) were conducted in dilated cardiomyopathy patients with a compensated phase of heart failure before discharge. Layer-specific longitudinal and circumferential strain was assessed from the endocardium, mid-myocardium, and epicardium by two-dimensional (2D) speckle-tracking echocardiography. The gradient between the endocardium and epicardium was calculated.

RESULTS

Patients with nonischemic etiology of dilated cardiomyopathy presented smaller values of global and layer strain than patients in the ischemic group. GLS, GLSend, GLSend-GLSepi, CSPMend, CSPMend-CSPMepi, CSAP, CSAPend, and CSAPend-CSAPepi were the parameters with statistically significant decreased values in non-survivors compared with survivors. In multivariate analysis, only CSPMend showed an independent value in predicting mortality at two-year follow-up. Receiver operator curve analysis provided CSPMend of -10.8% as a cut-off value with a sensitivity of 80% and specificity of 61.05% in identifying the dilated cardiomyopathy and heart failure patients with a risk of death at two-year follow-up.

CONCLUSIONS

GLS, GCS, and layer-specific strain analysis showed decreased values in nonischemic compared with ischemic dilated cardiomyopathy and also in non-survivors compared with survivors. CSPMend was the most sensitive strain parameter to identify patients with increased mortality risk at two-year follow-up.

Mechanoresponsive Drug Release from a Flexible, Tissue-Adherent, Hybrid Hydrogel Actuator

Soft robotic technologies for therapeutic biomedical applications require conformal and atraumatic tissue coupling that is amenable to dynamic loading for effective drug delivery or tissue stimulation. This intimate and sustained contact offers vast therapeutic opportunities for localized drug release. Herein, a new class of hybrid hydrogel actuator (HHA) that facilitates enhanced drug delivery is introduced. The multi-material soft actuator can elicit a tunable mechanoresponsive release of charged drug from its alginate/acrylamide hydrogel layer with temporal control. Dosing control parameters include actuation magnitude, frequency, and duration. The actuator can safely adhere to tissue via a flexible, drug-permeable adhesive bond that can withstand dynamic device actuation. Conformal adhesion of the hybrid hydrogel actuator to tissue leads to improved mechanoresponsive spatial delivery of the drug. Future integration of this hybrid hydrogel actuator with other soft robotic assistive technologies can enable a synergistic, multi-pronged treatment approach for the treatment of disease.

The utility of novel STE parameters in echocardiographic assessment of single ventricle after Fontan palliation

Background and aims of the study A functionally single ventricle (FSV) refers to a group of congenital heart defects that are not amenable for biventricular correction. The Fontan operation is utilized as surgical treatment for most of FSV patients. The evaluation of FSV function is extremely difficult due to its unique pathophysiology. This study aimed to explore the efficacy of speckle tracking echocardiography (STE) parameters measured at rest and during exercise for comprehensive assessment of univentricular heart.

METHODS

We enrolled 37 patients with a functionally single ventricle after the Fontan operation, hospitalized in the Department of Congenital Heart Defects between years 2019 and 2021.The echocardiographic stress tests were performed in the Echocardiography Laboratory of the Congenital Heart Defects Department. The study was conducted on a bicycle ergometer in a semi-recumbent position. The parameters obtained by speckle tracking echocardiography (STE): the longitudinal strain of the FSV free wall (Ɛ) and the longitudinal strain of myocardial layers: subendocardial, medial and subepicardial were analyzed. A transmural longitudinal strain gradient (TG) was calculated as the difference between longitudinal deformation of the subendocardial and subepicardial layers. Current results of cardiac magnetic resonance imaging (CMR) and cardio-pulmonary test (CPET) were also incorporated. Demographic data, past interventions, pharmacological treatment and comorbidities were extracted from medical records.

RESULTS

Ɛ at rest and during exercise were not related to the parameters of physical capacity obtained on CPET nor to the CMR results. The transmural strain gradient was dependent on physical performance parameter- peak oxygen uptake- and related to the FSV ejection fraction calculated by magnetic resonance imaging.

CONCLUSIONS

The transmural strain gradient and FSV free wall strain are readily measurable and suitable for evaluating single ventricle function. The TG is positively correlated with peak oxygen uptake during the cardiopulmonary test and with the ejection fraction derived from cardiac magnetic resonance imaging. The applicability of these findings in patients undergoing the Fontan procedure warrants further exploration.

Implanted Carbon Nanotubes Harvest Electrical Energy from Heartbeat for Medical Implants

Reliability of power supply for current implantable electronic devices is a critical issue for longevity and for reducing the risk of device failure. Energy harvesting is an emerging technology, representing a strategy for establishing autonomous power supply by utilizing biomechanical movements in human body. Here, a novel "Twistron energy cell harvester" (TECH), consisting of coiled carbon nanotube yarn that converts mechanical energy of the beating heart into electrical energy, is presented. The performance of TECH is evaluated in an in vitro artificial heartbeat system which simulates the deformation pattern of the cardiac surface, reaching a maximum peak power of 1.42 W kg-1 and average power of 0.39 W kg-1 at 60 beats per minute. In vivo implantation of TECH onto the left ventricular surface in a porcine model continuously generates electrical energy from cardiac contraction. The generated electrical energy is used for direct pacing of the heart as documented by extensive electrophysiology mapping. Implanted modified carbon nanotubes are applicable as a source for harvesting biomechanical energy from cardiac motion for power supply or cardiac pacing.

Characterizing collagen scaffold compliance with native myocardial strains using an ex-vivo cardiac model: The physio-mechanical influence of scaffold architecture and attachment method

Applied to the epicardium in-vivo, regenerative cardiac patches support the ventricular wall, reduce wall stresses, encourage ventricular wall thickening, and improve ventricular function. Scaffold engraftment, however, remains a challenge. After implantation, scaffolds are subject to the complex, time-varying, biomechanical environment of the myocardium. The mechanical capacity of engineered tissue to biomimetically deform and simultaneously support the damaged native tissue is crucial for its efficacy. To date, however, the biomechanical response of engineered tissue applied directly to live myocardium has not been characterized. In this paper, we utilize optical imaging of a Langendorff ex-vivo cardiac model to characterize the native deformation of the epicardium as well as that of attached engineered scaffolds. We utilize digital image correlation, linear strain, and 2D principal strain analysis to assess the mechanical compliance of acellular ice templated collagen scaffolds. Scaffolds had either aligned or isotropic porous architecture and were adhered directly to the live epicardial surface with either sutures or cyanoacrylate glue. We demonstrate that the biomechanical characteristics of native myocardial deformation on the epicardial surface can be reproduced by an ex-vivo cardiac model. Furthermore, we identified that scaffolds with unidirectionally aligned pores adhered with suture fixation most accurately recapitulated the deformation of the native epicardium. Our study contributes a translational characterization methodology to assess the physio-mechanical performance of engineered cardiac tissue and adds to the growing body of evidence showing that anisotropic scaffold architecture improves the functional biomimetic capacity of engineered cardiac tissue. STATEMENT OF SIGNIFICANCE: Engineered cardiac tissue offers potential for myocardial repair, but engraftment remains a challenge. In-vivo, engineered scaffolds are subject to complex biomechanical stresses and the mechanical capacity of scaffolds to biomimetically deform is critical. To date, the biomechanical response of engineered scaffolds applied to live myocardium has not been characterized. In this paper, we utilize optical imaging of an ex-vivo cardiac model to characterize the deformation of the native epicardium and scaffolds attached directly to the heart. Comparing scaffold architecture and fixation method, we demonstrate that sutured scaffolds with anisotropic pores aligned with the native alignment of the superficial myocardium best recapitulate native deformation. Our study contributes a physio-mechanical characterization methodology for cardiac tissue engineering scaffolds.

Utilizing Artificial Intelligence-Based Deformable Registration for Global and Layer-Specific Cardiac MRI Strain Analysis in Healthy Children and Young Adults

RATIONALE AND OBJECTIVES

The absence of published reference values for multilayer-specific strain measurement using cardiac magnetic resonance (CMR) in young healthy individuals limits its use. This study aimed to establish normal global and layer-specific strain values in healthy children and young adults using a deformable registration algorithm (DRA).

MATERIALS AND METHODS

A retrospective study included 131 healthy children and young adults (62 males and 69 females) with a mean age of 16.6 ± 3.9 years. CMR examinations were conducted using 1.5T scanners, and strain analysis was performed using TrufiStrain research prototype software (Siemens Healthineers, Erlangen, Germany). Global and layer-specific strain parameters were extracted from balanced Steady-state free precession cine images. Statistical analyses were conducted to evaluate the impact of demographic variables on strain measurements.

RESULTS

The peak global longitudinal strain (LS) was -16.0 ± 3.0%, peak global radial strain (RS) was 29.9 ± 6.3%, and peak global circumferential strain (CS) was -17.0 ± 1.8%. Global LS differed significantly between males and females. Transmural strain analysis showed a consistent pattern of decreasing LS and CS from endocardium to epicardium, while radial strain increased. Basal-to-apical strain distribution exhibited decreasing LS and increasing CS in both global and layer-specific analysis.

CONCLUSION

This study uses DRA to provide reference values for global and layer-specific strain in healthy children and young adults. The study highlights the impact of sex and age on LS and body mass index on RS. These insights are vital for future cardiac assessments in children, particularly for early detection of heart diseases.

Limitations of Diagnosis of Ischemic Left Ventricular Dysfunction Using the Values of Strain, Twist and Untwist in Patients With Myocardial Infarction of Various Localization

AIM

To compare capabilities for diagnosing regional and global myocardial dysfunction using the values of longitudinal and circular strain, left ventricular (LV) torsion and untwisting in patients with myocardial infarction (MI) of various locations.

MATERIAL AND METHODS

Patients included in the study (n=121) were divided into three groups: patients with unstable angina (n=30), patients with anterior MI (n=45), and patients with inferior MI (n=46). Clinical, laboratory and instrumental test were performed, including echocardiography. For a quantitative analysis of LV contractility, the maximum systolic peaks of regional and global longitudinal and circular strain, systolic and diastolic rotation, LV torsion and untwisting were measured.

RESULTS

Anterior MI was characterized by injury of the LV apical segments, while inferior MI was characterized by injury of the basal segments. In anterior MI, the longitudinal strain was reduced less than 14.5% and circular strain less than 19.3% in the apical segment of the LV anteroseptal wall (ASW). In akinesia of the LV ASW apical segment, longitudinal and circular strains were reduced less than 10%. The magnitude of the circular strain of the LV ASW apical segment (diagnostic threshold 19.3%, sensitivity (Se) 87%, specificity (Sp) 90%) was superior to that of the longitudinal strain as a diagnostic marker for regional ischemic dysfunction in anterior MI. The magnitude of the circular strain of the basal segment of the LV inferior wall in inferior MI has a greater diagnostic value for identifying regional systolic dysfunction than the value of the longitudinal strain of this LV segment. The diagnostic threshold was 17.3%, Se 79%, Sp 80%.

CONCLUSION

A decrease in the circular strain of the LV ASW less than 19.3% in the LV apical segment is more specific (Sp 90%) for diagnosing regional systolic dysfunction in anterior MI than a decrease in longitudinal strain. A circular strain value of less than 17.3% in the basal segment of the LV inferior wall is more specific (Sp 80%) than the longitudinal strain of this segment for diagnosing regional systolic dysfunction in inferior MI. Predominant injury to the LV apex in anterior MI can cause systolic and diastolic myocardial dysfunction, which is manifested by a decrease in LV circular deformation, torsion and untwisting.

Evaluation of left ventricular function of pregnant women with autoimmune diseases using speckle tracking echocardiography

Pregnancy can cause fluctuations in autoimmune diseases (AD) women, which may aggravate the cardiac damage. Maternal heart function is very important for maternal and fetal health. Therefore, early and accurate evaluation of the heart function of AD pregnant women is necessary. This study was aimed to evaluate the left ventricular (LV) function of AD pregnant women using two-dimensional speckle tracking echocardiography (2DSTE). A total of 96 subjects, including 26 non-pregnant AD patients (AD group), 33 AD pregnant women (AD-P group), and 37 healthy pregnant women (H-P group) were conducted. Baseline clinical and conventional echocardiography characteristics of all the subjects were collected. The 2DSTE was performed to acquire layer-specific strain parameters of LV. Compared with H-P group, AD-P group showed no significant differences in GLSmid and GLSepi. However, the GLSendo (24.10 [22.30 to 25.40] vs. 21.70 [19.05 to 25.15], P = 0.023) and ΔGLS (5.50 [4.80 to 6.00] vs. 4.90 [4.20 to 5.80], P = 0.017) were decreased, while the PSD (27 [23 to 32] vs. 32 [24 to 44], P = 0.014) was increased. At the segmental level, there was no significant difference in apex LSmid and LSepi between the two groups, while the AD-P group showed transmural dysfunction in basal and middle segments, and the LSendo in apex segments (32.84 [28.34 to 34.25] vs. 27.97 [21.87 to 33.61], P = 0.021) were significantly decreased. Compared with AD group, AD-P group showed no significant difference in ΔGLS, PSD, and GLS parameters of three layers. For the segmental level, there were no significant differences in the LSepi of the apex segment and the LS in three layers of the basal and middle segments between the two groups, while LSendo (32.69 [29.13 to 35.53] vs. 27.97 [21.87 to 33.60], P = 0.017) and LSmid (24.70 [22.24 to 27.78] vs. 21.32 [16.91 to 26.11], P = 0.023) in apex segments were significantly lower in AD-P group. The anti-SSA/Ro antibody were positive independently correlated with PSD. In conclusion, layer-specific strain parameters and PSD by 2DSTE provide an accurate and reproducible measurement of myocardial function. There are subclinical LV myocardial dysfunction in AD pregnant women. Besides, the positive of anti-SSA/Ro antibody maybe associated with LV myocardial dysfunction.

Role of two-dimensional strain echocardiographic parameters in suspected acute coronary syndrome patients with initial non-diagnostic electrocardiogram and troponins: An observational study

INTRODUCTION

Diagnosis of acute coronary syndrome (ACS) is often challenging especially in presence of initial normal troponins and non-specific electrocardiogram. The index study aimed at determining the diagnostic value of strain echocardiography in patients with suspected ACS but with non-diagnostic electrocardiogram and echocardiography findings.

METHODS

The study was conducted on 42 patients with suspected ACS and non-diagnostic electrocardiograms, normal quantitative troponin-T levels, and left ventricular function. All patients underwent conventional and 2D-strain echocardiography followed by coronary angiography, within 24 h of admission. Patients with regional wall motion abnormalities (RWMA), valvular heart disease, suspected myocarditis, and past coronary artery disease (CAD) were excluded.

RESULTS

Amongst the global strains, the global circumferential strain (GCS) was significantly reduced (p = .014) amongst those with significant CAD on angiography as opposed to global longitudinal strain (GLS) which was similar in the two groups (p = .33). The GCS/GLS ratio was also significantly reduced in patients with significant CAD compared to those with normal/mild disease on coronary angiography (p = .025). Both the parameters had good accuracy in predicting significant CAD. GCS displayed a sensitivity of 80% and a specificity of 86% at an optimal cut-off 31.5% (AUROC: .93, 95% CI: .601-1.000; p = .03), and likewise GCS/GLS ratio had a sensitivity of 80% and a specificity and 86% at a cut-off of 1.89% (AUROC: .86, 95% CI: .592-1.000; p = .049). GLS and peak atrial longitudinal strain (PALS) did not differ significantly in patients with/without significant CAD (p = .32 and .58, respectively).

CONCLUSION

GCS and GCS/GLS ratio provides incremental value in comparison to GLS, PALS, and tissue Doppler indices (E/e') in patients with suspected ACS and non-diagnostic electrocardiogram and troponins. GCS at cut-off of >31.5% and GCS/GLS ratio >1.89 can reliably exclude patients with significant CAD in this setting.

ECHO provides layer-specific insight of both myocardial deformation and microcirculation dysfunction in dilated cardiomyopathy patients: Clinical value of combined application of left ventricular layer-specific strain and myocardial contrast echocardiography

AIM

To investigate the pattern of left ventricular (LV) function and myocardial perfusion and their relationship in dilated cardiomyopathy (DCM) patients using layer-specific speckle tracking imaging (STI) and layer-specific myocardial contrast echocardiography (MCE).

MATERIAL AND METHODS

Thirty DCM patients and 30 controls were recruited and underwent STI and MCE examination. The peak values of longitudinal strain (LS), circumferential strain (CS) of each layer of LV were recorded and compared between groups. Additionally, cross-sectional area of a microvessel (A) and average myocardial microvascular lesion (β) of each layer were measured, myocardial blood flow (MBF) was estimated using A × β, above parameters were compared between two groups.

RESULTS

The LS of endo- (LS_endo ), mid- (LS_mid ) and epicardium (LS_epi ), as well as CS of endo- (RS_endo ), mid- (RS_mid ), (LS_epi ) epicardium and LS endo/epi, CS endo/epi were significantly decreased in DCM patients. More importantly, DCM patients demonstrated decreased A, β and A × β in all three myocardium layers and A endo/epi, β endo/epi, A × β endo/epi compared to the controls. The time to peak and the cardiac cycle required to reach the peak were prolonged in DCM patients (p < 0.05). Longitudinal strain parameters of each layer had a negative relationship with perfusion parameter A and this relationship was strongest between LSendo and Aendo (r = 0.690, p < 0.01).

CONCLUSIONS

The cardiac strain and, more importantly, coronary microcirculation perfusion was impaired in each layer in DCM patients. The longitudinal function of the LV myocardium was closely related to changes in myocardial microcirculation perfusion.

Fibroblast Growth Factor 23: Potential Marker of Invisible Heart Damage in Diabetic Population

Two-dimensional speckle-tracking echocardiography (2DSTE) detects myocardial dysfunction despite a preserved left ventricular ejection fraction. Fibroblast growth factor 23 (FGF23) has become a promising biomarker of cardiovascular risk. This study aimed to determine whether FGF23 may be used as a marker of myocardial damage among patients with diabetes mellitus type 2 (T2DM) and no previous history of myocardial infarction. The study enrolled 71 patients with a median age of 70 years. Laboratory data were analyzed retrospectively. Serum FGF23 levels were determined using a sandwich enzyme-linked immunosorbent assay. All patients underwent conventional echocardiography and 2DSTE. Baseline characteristics indicated that the median time elapsed since diagnosis with T2DM was 19 years. All subjects were divided into two groups according to left ventricular diastolic function. Individuals with confirmed left ventricular diastolic dysfunction had significantly lower levels of estimated glomerular filtration rate and higher values of hemoglobin A1c. Global circumferential strain (GCS) was reduced in the majority of patients. Only an epicardial GCS correlated significantly with the FGF23 concentration in all patients. The study indicates that a cardiac strain is a reliable tool for a subtle myocardial damage assessment. It is possible that FGF23 may become an early diagnostic marker of myocardial damage in patients with T2DM.

Assessment of subclinical cardiac dysfunction by speckle-tracking echocardiography among people living with human immunodeficiency virus

Background

People living with HIV (PLWH) have an increased risk of developing cardiovascular diseases (CVD). As speckle-tracking echocardiography (STE) has been used to detect subclinical myocardial abnormalities, this study aims to detect early cardiac impairment among Asian PLWH using STE and to investigate the associated risk factors.

Methods

We consecutively recruited asymptomatic PLWH without previous CVD from a medical center of Taiwan, and their cardiac function was evaluated by conventional echocardiogram and STE. Enrolled PLWH were classified as antiretroviral therapy (ART)-experienced and ART-naive, and multivariable regressions were used to assess the association between myocardial strain and risk factors including traditional CVD and HIV-associated factors.

Results

A total of 181 PLWH (mean age: 36.4 ± 11.4 years, 173 males) were recruited and conventional echocardiogram parameters were within normal ranges. Decreased myocardial strain across the myocardium was found, with a mean left ventricular (LV) global longitudinal strain of -18.7 ± 2.9%. The LV strain in the ART-experienced group (-19.0 ± 2.9%) was significantly better than the ART-naive group (-17.9 ± 2.8%), despite a younger age and lesser CVD risk factors in the ART-naive group. Hypertension [B = 1.92, 95% confidence interval (95% CI) 0.19-3.62, p = 0.029] and ART-naive with both low and high viral loads (VL) (B = 1.09, 95% CI 0.03-2.16, p = 0.047; and B = 2.00, 95% CI, 0.22-3.79, p = 0.029) were significantly associated with reduced myocardial strain.

Conclusion

This is the first and largest cohort using STE to investigate myocardial strain in Asian PLWH. Our results suggest that hypertension and detectable VL are associated with impaired myocardial strain. Thus, timely ART administration with VL suppression and hypertension control are crucial in preventing CVD when making the management parallel with the improved life expectancy of PLWH on ART.

2D Strain Analysis in Myocarditis-Can We Be Any Closer to Diagnose the Acute Phase of the Disease?

BACKGROUND

The aim of present study was to assess left ventricular myocardial deformation detected by 2D STE in patients with suspected acute myocarditis (AM) early on admission in whom later cardiac magnetic resonance (CMR) evaluation was performed.

METHODS

A total of 47 patients with suspected AM based on clinical practice were prospectively enrolled. Coronary angiography was performed on all patients to rule out significant coronary artery disease. CMR confirmed myocardial inflammation, oedema, and regional necrosis meeting the Lake Louise criteria in 25 patients (53%, oedema (+) subgroup). In the remaining patients, only LGE was confirmed in the sub-epicardial or intramuscular localization (22 patients, 47%, oedema (-) subgroup). Early on admission, echocardiography with measurements of global and segmental longitudinal strains (GLS), circumferential strains (GCS) at the endocardial (endocardial GCS) and epicardial (epicardial GCS) layers, transmural GCS, and radial strains (RS) were performed.

RESULTS

Mild reduction of GLS, GRS, and transmural GCS values were found in patients with oedema (+) subgroup. The epicardial GCS turned out to be the diagnostic factor for oedema with a cut-off point of 13,0% (AUC 0.747, p = 0.0005). Twenty-two patients (all but three) with an acute phase of myocarditis and epicardial GCS -13.0% or less had oedema confirmed by CMR.

CONCLUSIONS

2D STE can help to set the diagnosis of AM in patients with acute chest pain with a normal coronary angiogram. The epicardial GCS can serve as a diagnostic factor for oedema in patients with early stage of AM. In patients presenting with signs of AM (oedema in CMR), the epicardial GCS is modified in comparison with a subgroup without oedema; therefore, this parameter could be used to improve the performance of ultrasound.

Normative healthy reference values for global and segmental 3D principal and geometry dependent strain from cine cardiac magnetic resonance imaging

3-Dimensional (3D) myocardial deformation analysis (3D-MDA) enables novel descriptions of geometry-independent principal strain (PS). Applied to routine 2D cine cardiovascular magnetic resonance (CMR), this provides unique measures of myocardial biomechanics for disease diagnosis and prognostication. However, healthy reference values remain undefined. This study describes age- and sex-stratified reference values from CMR-based 3D-MDA, including 3D PS. One hundred healthy volunteers were prospectively recruited following institutional ethics approval and underwent CMR imaging. 3D-MDA was performed using validated software. Age- and sex-stratified global and segmental strain measures were derived for conventional geometry-dependent [circumferential (CS), longitudinal (LS), and radial (RS)] and geometry-independent [minimum (minPS) and maximum principal (maxPS)] directions of deformation. Layer-specific contraction angle interactions were determined using local minPS vectors. The average age was 43 ± 15 years and 55% were women. Strain measures were higher in women versus men. 3D PS-based assessment of maximum tissue shortening (minPS) and maximum tissue thickening (maxPS) were greater than corresponding geometry-dependent markers of LS and RS, consistent with improved representation of local tissue deformations. Global maxPS amplitude best discriminated both age and sex. Segmental analyses showed greater strain amplitudes in apical segments. Transmural PS contraction angles were higher in females and showed a heterogeneous distribution across segments. In this study we provided age and sex-based reference values for 3D strain from CMR imaging, demonstrating improved capacity for 3D PS to document maximal local tissue deformations and to discriminate age and sex phenotypes. Novel markers of layer-specific strain angles from 3D PS were also described.

Age-, Sex-, and Race-Based Normal Values for Left Ventricular Circumferential Strain from the World Alliance Societies of Echocardiography Study

BACKGROUND

Left ventricular (LV) circumferential strain has received less attention than longitudinal deformation, which has recently become part of routine clinical practice. Among other reasons, this is because of the lack of established normal values. Accordingly, the aim of this study was to establish normative values for LV circumferential strain and determine sex-, age-, and race-related differences in a large cohort of healthy adults.

METHODS

Complete two-dimensional transthoracic echocardiograms were obtained in 1,572 healthy subjects (51% men), enrolled in the World Alliance Societies of Echocardiography Normal Values Study. Subjects were divided into three age groups (<35, 35-55, and >55 years) and stratified by sex and by race. Vendor-independent semiautomated speckle-tracking software was used to determine LV regional circumferential strain and global circumferential strain (GCS) values. Limits of normal for each measurement were defined as 95% of the corresponding sex and age group falling between the 2.5th and 97.5th percentiles. Intergroup differences were analyzed using unpaired t tests.

RESULTS

Circumferential strain showed a gradient, with lower magnitude at the mitral valve level, increasing progressively toward the apex. Compared with men, women had statistically higher magnitudes of regional and global strain. Older age was associated with a stepwise increase in GCS despite an unaffected ejection fraction, a decrease in LV volume, and relatively stable global longitudinal strain in men, with a small gradual decrease in women. Asian subjects demonstrated significantly higher GCS magnitudes than whites of both sexes and blacks among women only. In contrast, no significant differences in GCS were found between white and black subjects of either sex. Importantly, despite statistical significance of these differences across sex, age, and race, circumferential strain values were similar in all groups, with variations of the order of magnitude of 1% to 2%. Notably, no differences in GCS were found among brands of imaging equipment.

CONCLUSION

This study established normal values of LV regional circumferential strain and GCS and identified sex-, age-, and race-related differences when present.

Novel approach to artefact detection and the definition of normal ranges of segmental strain and strain-rate values

AIMS

Strain artefacts are known to hamper the correct interpretation of segmental strain and strain-rate (S/SR). Defining the normal ranges of myocardial segmental deformation is important in clinical studies and routine echocardiographic practice. In order to define artefact-free normal ranges for segmental longitudinal S/SR parameters, we investigated the extent to which different types of artefacts and their segmental localisation in the three different myocardial layers created a bias in the results of echocardiographic strain measurements.

METHODS

The study included echocardiograms from men and women aged 40-69 years from two population-based studies, namely the Know Your Heart study (Russia) and the Tromsø Study (Norway). Of the 2207 individuals from these studies, 840 had normal results, defined as the absence of hypertension or indicators of any cardiovascular disease. Two-dimensional (2D) global and segmental S/SR of the three myocardial layers were analysed using speckle tracking echocardiography. Artefacts were assessed with two different methods: visual identification of image-artefacts and a novel conceptual approach of 'curve-artefacts' or unphysiological strain-curve formation.

RESULTS

Segmental strain values were found to have significantly reduced in the presence of strain-curve artefacts (14.9%±5.8% towards -20.7%±4.9%), and increased with the foreshortening of the 2D image. However, the individual global strain values were not substantially altered by discarding segmental artefacts. Reduction due to artefacts was observed in all segments, layers, systolic and diastolic strain, and SR. Thus, we presented normal ranges for basal-septal, basal, medial and apical segment groups after excluding artefacts.

CONCLUSION

Strain-curve artefacts introduce systematic errors, resulting in reduced segmental S/SR values. In terms of artefact-robust global longitudinal strain, the detection of curve-artefacts is crucial for the correct interpretation of segmental S/SR patterns. Intersegmental S/SR gradients and artefacts need to be considered for the correct definition of normalcy and pathology.

Wet-Spun Polycaprolactone Scaffolds Provide Customizable Anisotropic Viscoelastic Mechanics for Engineered Cardiac Tissues

Myocardial infarction is a leading cause of death worldwide and has severe consequences including irreversible damage to the myocardium, which can lead to heart failure. Cardiac tissue engineering aims to re-engineer the infarcted myocardium using tissues made from human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to regenerate heart muscle and restore contractile function via an implantable epicardial patch. The current limitations of this technology include both biomanufacturing challenges in maintaining tissue integrity during implantation and biological challenges in inducing cell alignment, maturation, and coordinated electromechanical function, which, when overcome, may be able to prevent adverse cardiac remodeling through mechanical support in the injured heart to facilitate regeneration. Polymer scaffolds serve to mechanically reinforce both engineered and host tissues. Here, we introduce a novel biodegradable, customizable scaffold composed of wet-spun polycaprolactone (PCL) microfibers to strengthen engineered tissues and provide an anisotropic mechanical environment to promote engineered tissue formation. We developed a wet-spinning process to produce consistent fibers which are then collected on an automated mandrel that precisely controls the angle of intersection of fibers and their spacing to generate mechanically anisotropic scaffolds. Through optimization of the wet-spinning process, we tuned the fiber diameter to 339 ± 31 µm and 105 ± 9 µm and achieved a high degree of fidelity in the fiber structure within the scaffold (fiber angle within 1.8° of prediction). Through degradation and mechanical testing, we demonstrate the ability to maintain scaffold mechanical integrity as well as tune the mechanical environment of the scaffold through structure (Young’s modulus of 120.8 ± 1.90 MPa for 0° scaffolds, 60.34 ± 11.41 MPa for 30° scaffolds, 73.59 ± 3.167 MPa for 60° scaffolds, and 49.31 ± 6.90 MPa for 90° scaffolds), while observing decreased hysteresis in angled vs. parallel scaffolds. Further, we embedded the fibrous PCL scaffolds in a collagen hydrogel mixed with hiPSC-CMs to form engineered cardiac tissue with high cell survival, tissue compaction, and active contractility of the hiPSC-CMs. Through this work, we develop and optimize a versatile biomanufacturing process to generate customizable PCL fibrous scaffolds which can be readily utilized to guide engineered tissue formation and function.

Acute coronary syndrome versus acute myocarditis in young adults–value of speckle tracking echocardiography

Purpose

Comparing myocarditis with an acute coronary syndrome (ACS)-like presentation and acute myocardial infarction (AMI) poses an important clinical challenge. The purpose of the study was to investigate the diagnostic value of the clinical, laboratory and especially echocardiographic characteristics including speckle tracking echocardiography (STE) of patients with ACS-like myocarditis and AMI.

Methods

We conducted a retrospective analysis comparing 69 symptomatic patients (≤ 45 years old), hospitalized at the Department of Interventional Cardiology (Medical University of Lodz, Poland) between April 2014 and June 2021 with an initial diagnosis of ST-segment elevation myocardial infarction.

Results

37 patients with the cardiac magnetic resonance–confirmed acute myocarditis and 32 patients diagnosed with AMI based on the clinical presentation, electrocardiogram and the presence of a culprit lesion on the coronary angiography were analysed including echocardiography parameters. On STE analysis an average global longitudinal (GLS), radial and circumferential strain including three—layers observation were significantly lower (absolute value) in patients with AMI versus acute myocarditis (p<0.05). There was no significant difference in Endo/Epi ratio (p = 0.144) between the groups. An average GLS < (-17.5) represented the optimal cut-off value for the myocarditis diagnosis.

Conclusion

In patients with AMI a significant reduction of global and three-layers strains compared to patients with myocarditis was detected. Furthermore, our analysis also confirmed the discriminative pattern of myocardial injury between the groups.

High-Spatiotemporal-Resolution Visualization of Myocardial Strains Through Vector Doppler Estimation: A Small-Animal Study

High-frequency ultrasound (HFUS) imaging is extensively used for cardiac diseases in small animals due to its high spatial resolution. However, there is a lack of a system that can provide a 2-D high-spatiotemporal dynamic visualization of mouse myocardial strains. In this article, a dynamic HFUS (40 MHz) high-resolution strain imaging was developed through the vector Doppler imaging. Following in vitro tests using a rubber balloon phantom, in vivo experiments were performed on wild-type (WT) and myocardial infarction (MI) mice. High-resolution dynamic images of myocardial strains were obtained in the longitudinal, radial, and circumferential directions at a frame rate of 1 kHz. Global peak strain values for WT mice were -19.3% ± 1.3% (longitudinal), 31.4% ± 1.7% (radial in the long axis), -19.9% ±.8% (circumferential), and 34.4% ± 1.9% (radial in the short axis); those for the MI mice were -16.1% ±.9% (longitudinal), 26.8% ± 2.9% (radial in the long axis), -15.2% ± 2.7% (circumferential), and 21.6% ± 4.8% (radial in the short axis). These results indicate that the strains for MI mice are significantly lower than those for WT mice. Regional longitudinal strain curves in the epicardial, midcardial, and endocardial layers were measured and the peak strain values for WT mice were -22.% and -16.8% in the endocardial and epicardial layers, respectively. However, no significant difference in the layer-based values was noted for the MI mice. Regional analysis results revealed obvious myocardial strain variation in the apical anterior region in the MI mice. The experimental results demonstrate that the proposed dynamic cardiac strain imaging can be useful in high-performance imaging of small-animal cardiac diseases.

Role of Myocardial Strain Imaging in Cancer Therapy-Related Cardiac Dysfunction

PURPOSE OF REVIEW

This review aims to provide a contemporary perspective on the role of myocardial strain imaging in the management of patients on cardiotoxic therapy.

RECENT FINDINGS

Risk/benefit evaluation of cardiotoxic cancer treatment remains challenging, weighing life-saving cancer therapy with fatal cardiac dysfunction potentially caused by cancer therapy. The serial change in left ventricular ejection fraction (LVEF) was conventionally used for the detection of cancer therapy-related cardiac dysfunction (CTRCD). Peak systolic global longitudinal strain (GLS) by speckle-tracking echocardiography has turned into a vital pre- and post-chemotherapy assessment for the early detection of cardiotoxicity. Complexity in cardiotoxic therapy regimen, different definition of CTRCD by LVEF, variations in GLS values, timings, and variable cutoffs make it challenging to standardize the protocol for the detection of CTRCD. GLS > 15% relative reduction from baseline has been widely used. Evidence suggests that GLS could predict early subclinical LV dysfunction, and initiation of cardioprotective therapy led to less decline of LV function. Most of the studies used an echocardiographic endpoint, and the impact of GLS on the long-term clinical outcome is not established. GLS has emerged as a reliable measure to identify early subclinical LV dysfunction by detecting myocardial deformation in patients on cardiotoxic chemotherapy. To date, a significant decline in GLS suggests the initiation of cardioprotective therapy with close monitoring. Interruption of prognostically important cardiotoxic chemotherapies requires a multidisciplinary team approach guided mainly by LVEF and other clinical factors. Further randomized control trials with hard clinical endpoints and longer follow-ups may help to determine the role of GLS in CTRCD.

Electrocardiographic Characteristics and Their Correlation with Echocardiographic Alterations in Fabry Disease

Fabry disease (FD) is an X-linked disorder with α-galactosidase A deficiency. Males (>30 years) and females (>40 years) often present with cardiac manifestations, predominantly left ventricular hypertrophy (LVH). The aim of this study was to evaluate electrocardiographic (ECG) characteristics within FD patients to identify gender related differences, and to additionally explore the association of ECG parameters with structural and functional alterations on transthoracic echocardiography (TTE). Retrospective cross-sectional analysis of 45 FD patients with contemporaneous ECG and TTE was performed and compared to age and gender matched healthy controls. FD patients demonstrated alterations in several ECG parameters particularly in males, including prolonged P-wave duration (91 vs. 81 ms, p = 0.022), prolonged QRS duration (96 vs. 84 ms, p < 0.001), increased R-wave amplitude in lead I (8.1 vs. 5.7 mV, p = 0.047), increased Sokolow–Lyon index (25 vs. 19 mV, p = 0.002) and were more likely to meet LVH criteria (31% vs. 7%, p = 0.006). FD patients with impaired basal longitudinal strain (LS) on TTE were more likely to meet LVH criteria (41% vs. 0%, p = 0.018). Those with more advanced FD (increased LV wall thickness on TTE) were more likely to meet LVH criteria but additionally demonstrated prolonged ventricular depolarization (QRS duration 101 vs. 88 ms, p = 0.044). Therefore, alterations on ECG demonstrating delayed atrial activation, delayed ventricular depolarization and evidence of LVH were more often seen in male FD patients. Impaired basal LS, a TTE marker of early cardiac involvement, correlated with ECG abnormalities. Increased LV wall thickness on TTE, a marker of more advanced FD, was associated with more severe ECG abnormalities.

How to standardize measurement of global longitudinal strain

Global longitudinal strain (GLS) is a robust and sensitive marker of left-ventricular systolic function, reflecting longitudinal shortening of the ventricle. A growing body of evidence indicates its superiority in identifying subclinical, early alterations in cardiac function compared to traditional markers, such as ejection fraction. Therefore, there is a growing demand to assess GLS in clinical settings, but limited availability on how to obtain GLS accurately and appropriately in the current literature. This review summarizes key aspects of GLS measurement, including image acquisition, post-processing, and training/experience needed to facilitate the clinical implication with standardization.

Layer-Specific Global Longitudinal Strain Predicts Arrhythmic Risk in Arrhythmogenic Cardiomyopathy

Background: Arrhythmogenic cardiomyopathy (AC) is a life-threatening disease which predispose to malignant arrhythmias and sudden cardiac death (SCD) in the early stages of the disease. Risk stratification relies on the electrical, genetic, and imaging data. Our study aimed to investigate how myocardial deformation parameters may identify the subjects at risk of known predictors of major ventricular arrhythmias.

Methods: A cohort of 45 subjects with definite or borderline diagnosis of AC was characterized using the advanced transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) and divided into the groups according to the potential arrhythmic risk markers, such as non-sustained ventricular tachycardia (NSVT), late gadolinium enhancement (LGE), and genetic status. Layer-specific global longitudinal strain (GLS) by TTE 2D speckle tracking was compared in patients with and without these arrhythmic risk markers.

Results: In this study, 23 (51.1%) patients were men with mean age of 43 ± 16 years. Next-generation sequencing identified a potential pathogenic mutation in 39 (86.7%) patients. Thirty-nine patients presented LGE (73.3%), mostly located at the subepicardial-to-mesocardial layers. A layer-specific-GLS analysis showed worse GLS values at the epicardial and mesocardial layers in the subjects with NSVT and LGE. The epicardial GLS values of −15.4 and −16.1% were the best cut-off values for identifying the individuals with NSVT and LGE, respectively, regardless of left ventricular ejection fraction (LVEF).

Conclusions: The layer-specific GLS assessment identified the subjects with high-risk arrhythmic features in AC, such as NSVT and LGE. An epicardial GLS may emerge as a potential instrument for detecting the subjects at risk of SCD in AC.

Quantitative evaluation of fetal ventricular function by speckle tracking echocardiography

METHODS

The study included 59 patients with normal fetal heart structure, blood flow, and heart rhythm (fetal abnormality-negative group) and 50 patients with abnormal fetal heart structure, blood flow, and/or heart rhythm (fetal abnormality-positive group). Automated Cardiac Motion Quantification (aCMQ) was performed in both groups to obtain left and right ventricular endocardial global longitudinal strain (GLSendo), mid-myocardial global longitudinal strain (GLSmid), and epicardial global longitudinal strain (GLSepi). Parameters between the two groups were compared and correlation analyses performed. A deformation analysis was performed by two trained observers, and reproducibility was assessed.

RESULTS

The fetal left ventricular and right ventricular global longitudinal strain (LV-GLS and RV-GLS, respectively) decreased in a gradient from the endocardium to the epicardium. LV-GLS and RV-GLS of all myocardial layers were lower in the fetal abnormality-positive than -negative group (all P < 0.05). Correlation analysis showed that neither LV-GLS nor RV-GLS was significantly correlated with gestational age in the fetal abnormality-negative group (all P > 0.05), whereas left ventricular GLSendo, GLSmid, and GLSepi were negatively correlated with gestational age in the fetal abnormality-positive group (r = -.39 to -.44, all P < 0.05). Repeatability testing showed that the inter-observer and intra-observer intra-class correlation coefficients for LV-GLS and RV-GLS in each myocardial layer were >.75 (all P < 0.001).

CONCLUSIONS

As a new speckle tracking echocardiography tool, aCMQ has feasibility and repeatability in evaluating myocardial deformation of the fetal ventricle. This technique might provide helpful information on ventricular myocardial deformation in fetal hearts with abnormal structure or rhythm for clinical guidance in pregnancy.

Echocardiography in Women: How Are Mars and Venus Different?

PURPOSE OF REVIEW

Sex is an important determinant of cardiac structure and function. We review key sex differences in universal echocardiographic parameters and discuss the clinical implications of using sex-specific algorithms to increase the diagnostic accuracy of echocardiography and improve the timely treatment of common cardiovascular disorders, and the unique role of echocardiography in pregnancy and the evaluation of ischemic heart disease.

RECENT FINDINGS

Emerging echocardiographic findings have begun to define important sex-based differences in chamber size and ventricular function. We advocate for additional research and the consideration of sex-specific algorithms in future expert consensus guidelines for the diagnosis and treatment of valvular heart disease, heart failure, and thoracic aortic disease. Echocardiography is an essential diagnostic tool in our armamentarium of imaging modalities for the sex-specific diagnosis and guidance of treatment for a broad spectrum of cardiovascular disorders.

Value of layer-specific speckle tracking echocardiography for early detection of myocardial injury caused by chemotherapy in breast cancer patients with cardiovascular risk

The probability of toxicity-related myocardial injury event with anthracyclines is controversial, which could be related to the underlying cardiac status before chemotherapy. Our study sought to investigate the influence of cardiovascular risk factors on myocardial motion and cardiac function using layer-specific speckle tracking echocardiography (STE) during chemotherapy with epirubicin. Female patients with first-diagnosed breast cancer were prospectively enrolled in our study and received 4 chemotherapeutic cycles with epirubicin in each cycle of 21 days. All patients underwent echocardiography for layer-specific STE analysis before and after all chemotherapy. Clinical data including cardiovascular risk factors were collected. According to the Framingham score, patients with cardiovascular risk factors were divided into groups with low, medium, and high risk. 134 patients existed in the final analysis. The accumulated dose of epirubicin for were 560.0 ± 103.8 mg. 97 (72.4%) patients had cardiovascular risk factors. According to the Framingham score, 57 (42.5%) patients categorized in high risk. Endocardial layer strain after chemotherapy were lower than those at baseline (p < 0.05, all), especially for patients with high risk. The changes of endocardial longitudinal strain during chemotherapy were associated with cardiovascular risks at baseline with correlation coefficient of 0.627. Our study found that layer-specific STE is valuable for early detection of toxicity-related myocardial injury for patients with breast cancer after epirubicin chemotherapy and cardiovascular risk factors have greatly influenced on cardiac function during chemotherapy. The endocardial layer strain is sensitive to evaluate early-stage toxicity-related myocardial injury after epirubicin chemotherapy.

3D Myocardial Mechanical Wave Measurements: Toward In Vivo 3D Myocardial Elasticity Mapping

OBJECTIVES

This study aimed to investigate the potential of a novel 3-dimensional (3D) mechanical wave velocity mapping technique, based on the natural mechanical waves produced by the heart itself, to approach a noninvasive 3D stiffness mapping of the left ventricle.

BACKGROUND

Myocardial fibrosis is recognized as a pathophysiological substrate of major cardiovascular disorders such as cardiomyopathies and valvular heart disease. As fibrosis leads to increased myocardial stiffness, ultrasound elastography measurements could provide important clinical information.

METHODS

A 3D high frame rate imaging sequence was implemented on a high-end clinical ultrasound scanner to achieve 820 volumes/s when gating over 4 consecutive cardiac cycles. Five healthy volunteers and 10 patients with various degrees of aortic stenosis were included to evaluate feasibility and reproducibility. Mechanical waves were detected using the novel Clutter Filter Wave Imaging approach, shown to be highly sensitive to the weak tissue displacements caused by natural mechanical waves.

RESULTS

3D spatiotemporal maps of mechanical wave velocities were produced for all subjects. Only the specific mechanical wave at atrial contraction provided a full 3D coverage of the left ventricle (LV). The average atrial kick propagation velocity was 1.6 ± 0.2 m/s in healthy volunteers and 2.8 ± 0.8 m/s in patients (p = 0.0016). A high correlation was found between mechanical wave velocity and age (R² = 0.88, healthy group), septal wall thickness (R² = 0.73, entire group), and peak jet velocity across the aortic valve (R² = 0.70). For 3 of the patients, the higher mechanical wave velocity coexisted with the presence of late gadolinium enhancement on cardiac magnetic resonance.

CONCLUSIONS

In this study, 3D LV mechanical wave velocities were visualized and measured in healthy volunteers and patients with aortic stenosis. The proposed imaging sequence and measurement technique allowed, for the first time, the measurement of full spatiotemporal 3D elasticity maps of the LV using ultrasound. (Ultrasonic markers for myocardial fibrosis and prognosis in aortic stenosis; NCT03422770).

Architected fibrous scaffolds for engineering anisotropic tissues

Mimicking the native three-dimensional microenvironment is of crucial importance when biofabricating a new healthcare material. One aspect of the native tissue that is often omitted when designing a suitable scaffold is its anisotropy. Not only is matching native mechanical properties important when designing implantable scaffolds or healthcare materials, but matching physiological structure is also important as many cell populations respond differently to fiber orientation. Therefore, novel aligned electrospun scaffolds with varying fiber angles and spacing of bundles were created and mechanically characterized. Through controlling the angle between the fibers in each layer of the scaffold, a range of different physiological anisotropic mechanical properties were achieved that encompasses values found in native tissues. Extrapolation of this mechanical data allowed for any native tissue's anisotropic Young's modulus to be mimicked by electrospinning fibers at a particular angle. These electrospun scaffolds were then incorporated with cell-laden hydrogels to create hybrid structures that contain the benefits of both scaffolding techniques with the ability to encapsulate cells in the hydrogel. To conclude, this study develops a novel bundled fiber scaffold that was architected to yield anisotropic properties matching native tissues.

Cardiac mechanostructure: Using mechanics and anisotropy as inspiration for developing epicardial therapies in treating myocardial infarction

The mechanical environment and anisotropic structure of the heart modulate cardiac function at the cellular, tissue and organ levels. During myocardial infarction (MI) and subsequent healing, however, this landscape changes significantly. In order to engineer cardiac biomaterials with the appropriate properties to enhance function after MI, the changes in the myocardium induced by MI must be clearly identified. In this review, we focus on the mechanical and structural properties of the healthy and infarcted myocardium in order to gain insight about the environment in which biomaterial-based cardiac therapies are expected to perform and the functional deficiencies caused by MI that the therapy must address. From this understanding, we discuss epicardial therapies for MI inspired by the mechanics and anisotropy of the heart focusing on passive devices, which feature a biomaterials approach, and active devices, which feature robotic and cellular components. Through this review, a detailed analysis is provided in order to inspire further development and translation of epicardial therapies for MI.

Evaluation of strain averaging area and strain estimation errors in a spheroidal left ventricular model using synthetic image data and speckle tracking

BACKGROUND

In majority of studies on speckle tracking echocardiography (STE) the strain estimates are averaged over large areas of the left ventricle. This may impair the diagnostic capability of the STE in the case of e.g. local changes of the cardiac contractility. This work attempts to evaluate, how far one can reduce the averaging area, without sacrificing the estimation accuracy that could be important from the clinical point of view.

METHODS

Synthetic radio frequency (RF) data of a spheroidal left ventricular (LV) model were generated using FIELD II package and meshes obtained from finite element method (FEM) simulation. The apical two chamber (A2C) view and the mid parasternal short axis view (pSAXM) were simulated. The sector encompassed the entire cross-section (full view) of the LV model or its part (partial view). The wall segments obtained according to the American Heart Association (AHA17) were divided into subsegments of area decreasing down to 3 mm2. Longitudinal, circumferential and radial strain estimates, obtained using a hierarchical block-matching method, were averaged over these subsegments. Estimation accuracy was assessed using several error measures, making most use of the prediction of the maximal relative error of the strain estimate obtained using the FEM derived reference. Three limits of this predicted maximal error were studied, namely 16.7%, 33% and 66%. The smallest averaging area resulting in the strain estimation error below one of these limits was considered the smallest allowable averaging area (SAAA) of the strain estimation.

RESULTS

In all AHA17 segments, using the A2C projection, the SAAA ensuring maximal longitudinal strain estimates error below 33% was below 3 mm2, except for the segment no 17 where it was above 278 mm2. The SAAA ensuring maximal circumferential strain estimates error below 33% depended on the AHA17 segment position within the imaging sector and view type and ranged from below 3-287 mm2. The SAAA ensuring maximal radial strain estimates error below 33% obtained in the pSAXM projection was not less than 287 mm2. The SAAA values obtained using other maximal error limits differ from SAAA values observed for the 33% error limit only in limited number of cases. SAAA decreased when using maximal error limit equal to 66% in these cases. The use of the partial view (narrow sector) resulted in a decrease of the SAAA.

CONCLUSIONS

The SAAA varies strongly between strain components. In a vast part of the LV model wall in the A2C view the longitudinal strain could be estimated using SAAA below 3 mm2, which is smaller than the averaging area currently used in clinic, thus with a higher resolution. The SAAA of the circumferential strain estimation strongly depends on the position of the region of interest and the parameters of the acquisition. The SAAA of the radial strain estimation takes the highest values. The use of a narrow sector could increase diagnostic capabilities of 2D STE.

Usefulness of a multiparametric evaluation including global longitudinal strain for an early diagnosis of acute myocarditis

Cardiac magnetic resonance imaging (CMRI) represents the main imaging modality for diagnosing acute myocarditis. However, its limited availability could entail missing or delayed diagnosis. A reduction of left ventricular global longitudinal strain (LV GLS) by speckle tracking echocardiography (STE) correlates with amount of oedema in acute myocarditis and here may be early detected. Aim was to evaluate the diagnostic and prognostic role of 3-layers LV GLS in patients with acute myocarditis. Out of 122 patients with suspected acute myocarditis, a total of 86 consecutive patients with CMRI-confirmed acute myocarditis admitted in two Italian institutions were retrospectively screened. Exclusion criteria were met in 29 patients because of poor acoustic window or missing data. A total of 57 patients were then included. Clinical characteristics, laboratory examinations, transthoracic echocardiography data and STE parameters were collected early after hospitalization. In the study population, mean age was 38.8 ± 15.6 years, the prevalence of male gender was 90%. On admission, 22 patients (39%) had fever (body temperature > 37.5 °), mean white blood cell (WBC) count was 10.9 ± 1.7/10^3 and overall LV ejection fraction was 50.1% ± 11.2. An epicardial LV GLS < 18% was present in 74% of patients, and a model including at least one of LV GLS < 18% (absolute value), fever and WBC > 10.0/10^3 was able to identify all patients with CMRI-diagnosed acute myocarditis. An epicardial LV GLS < 15.3% (absolute value) at baseline significantly predicted the lack of myocarditis resolution during follow-up (AUC 0.76, 95% CI 0.58-0.93, p = 0.02). A multiparametric model including epicardial LV GLS, fever and elevated WBC count on admission could be useful for early diagnosing an acute myocarditis, especially when CMRI is not promptly available. Baseline epicardial LV GLS may also identify patients with less-likely myocarditis resolution.

In Vivo Comparison of Multiline Transmission and Diverging Wave Imaging for High-Frame-Rate Speckle-Tracking Echocardiography

High-frame-rate (HFR) speckle-tracking echocardiography (STE) assesses myocardial function by quantifying motion and deformation at high temporal resolution. Among the proposed HFR techniques, multiline transmission (MLT) and diverging wave (DW) imaging have been used in this context both being characterized by specific advantages and disadvantages. Therefore, in this article, we directly contrast both approaches in an in vivo setting while operating at the same frame rate (FR). First, images were recorded at baseline (resting condition) from healthy volunteers and patients. Next, additional acquisitions during stress echocardiography were performed on volunteers. Each scan was contoured and processed by a previously proposed 2-D HFR STE algorithm based on cross correlation. Then, strain curves and their end-systolic (ES) values were extracted for all myocardial segments for further statistical analysis. The baseline acquisitions did not reveal differences in estimated strain between the acquisition modes ( ); myocardial segments ( ); or an interaction between imaging mode and depth ( ). Similarly, during stress testing, no difference ( p = 0.7 ) was observed for the two scan sequences, stress levels or an interaction sequence-stress level ( p = 0.94 ). Overall, our findings show that MLT and DW compoundings give comparable HFR STE strain values and that the choice for using one method or the other may thus rather be based on other factors, for example, system requirements or computational cost.

Integrating Measures of Myocardial Fibrosis in the Transition from Hypertensive Heart Disease to Heart Failure

PURPOSE OF REVIEW

This review aims to summarize recent developments in identifying and quantifying both the presence and amount of myocardial fibrosis by imaging and biomarkers. Further, this review seeks to describe in general ways how this information may be used to identify hypertension and the transition to heart failure with preserved ejection fraction.

RECENT FINDINGS

Recent studies using cardiac magnetic resonance imaging highlight the progressive nature of fibrosis from normal individuals to those with hypertension to those with clinical heart failure. However, separating hypertensive patients from those with heart failure remains challenging. Recent studies involving echocardiography show the subclinical myocardial strain changes between hypertensive heart disease and heart failure. Lastly, recent studies highlight the potential use of biomarkers to identify those with hypertension at the greatest risk of developing heart failure. In light of the heterogeneous nature between hypertension and heart failure with preserved ejection fraction, an integrated approach with cardiac imaging and biomarker analysis may enable clinicians and investigators to more accurately characterize, prevent, and treat heart failure in those with hypertension.

Reliability of left atrial strain reference values: A 3D echocardiographic study

Background

Standard apical four-chamber and two-chamber views often maximize the long-axis of the left ventricle, resulting in artifactitious foreshortening of the left atrium (LA), which may overestimate LA longitudinal reservoir strain (LALS). We compared LALS values between 2D echocardiography (2DE) and 3D echocardiography (3DE) in healthy subjects to determine whether 2DE speckle tracking analysis overestimates the reference value of LALS.

Methods and results

In this study, 4 types of cohorts were included: 1. 105 normal subjects (retrospectively), 2. 53 patients with cardiovascular diseases (retrospectively), 3. 15 patients who received cardiac magnetic resonance (prospectively), and 4. 20 normal subjects (prospectively). LALS and LA length were measured using both 2DE and 3DE in 105 healthy subjects (median age: 42 years). Biplane LALS was measured in apical four- and two-chamber views using 2DE speckle tracking software, and 3DE LALS was measured using new 3DE LA strain software. To determine sensitivity, we also performed the same analysis in 53 patients with cardiovascular disease. The mean value of biplane LALS was 39.6%. LA length at both end-diastole (r = -0.43) and end-systole (r = -0.54) was negatively correlated with biplane LALS. Multivariate regression analysis revealed that both end-diastolic and end-systolic LA length had significant negative relationships with biplane LALS after adjusting for anthropometric and echocardiographic image quality parameters. 3DE LALS (23.7±7.6%) gave significantly lower values than 2DE LALS (39.5±12.0%, p<0.001) with a weak correlation (r = 0.33). LA length measured by 2DE was significantly shorter than that measured by 3DE. The same trend was observed in diseased patients.

Conclusions

Our results revealed that in 2DE, the LA cavity consistently appears longitudinally foreshortened in apical views, potentially overestimating LALS. 3DE may overcome this limitation.

Layer-specific strain echocardiography may reflect regional myocardial impairment in patients with hypertrophic cardiomyopathy

Our study aimed to determine whether layer-specific strain (LSS) could reflect regional myocardial impairment in patients with hypertrophic cardiomyopathy (HCM). The study enrolled 50 patients with HCM and 30 age-matched healthy controls. Transmural gradient of longitudinal strain (TGLS), defined as the difference between the longitudinal strain of the endocardium and epicardium in a left ventricular segment, was used to reflect layer-specific myocardial impairment. Negative TGLS was consistently observed in healthy controls. The TGLS was relatively consistent within the basal, middle, and apical levels in healthy controls,but showed a significant gradient from the base towards the apex. In patients with HCM, the hypertrophic segments had significantly higher TGLS than the relatively normal segments or healthy controls at all 3 levels (0.14 % ± 3.48 % vs. -2.65 % ± 4.44 % vs. -2.17 % ± 1.66 % for basal, - 0.72 % ± 3.71 % vs. -4.02 % ± 4.00 % vs. -3.58 % ± 2.29 % for middle, and - 8.69 % ± 7.96 % vs. -11.44 % ± 6.65 % vs. -10.04 % ± 3.20 % for apex). Abnormal TGLS, defined as positive TGLS, in patients with HCM was associated with chest pain. In receiver operating characteristic curve analysis, a large area of abnormal TGLS (> 4 segments) had moderate accuracy for predicting chest pain (sensitivity, 73.3 %; specificity, 70.0 %). TGLS, a novel LSS derived parameter, may reflect regional myocardial impairment in patients with HCM.

Age- and sex-based normal values of layer-specific longitudinal and circumferential strain by speckle tracking echocardiography: the Copenhagen City Heart Study

AIMS

Technical advancements in 2D-speckle tracking echocardiography (2DSTE) have allowed for quantification of layer-specific global longitudinal strain (GLS) and circumferential strain (GCS) of the left ventricle (LV). The aim of this study was to establish age- and sex-based reference ranges of peak systolic layer-specific GLS and GCS and to assess normal values of regional strain.

METHODS AND RESULTS

We performed 2DSTE analysis of 1997 members of the general population from the fifth round of the Copenhagen City Heart Study, who were free of cardiovascular disease and risk factors. The mean age was 46 ± 16 years (range 21-97) and 62% were female. Mean values for peak systolic whole wall GLS (GLSWW.Sys), endomycardial (GLSEndo.Sys), and epimyocardial (GLSEpi.Sys) were 19.9 ± 2.1% (prediction interval [PI]: 15.8-24.0%), 23.5 ± 2.5% (PI: 18.6-28.4%), and 17.3 ± 1.9% (PI: 13.6-21.1%), respectively. Mean peak systolic whole wall GCS (GCSWW.Sys), was 21.6 ± 3.7% (PI: 14.3-28.9%), endomyocardial (GCSEndo.Sys) was 31.9 ± 4.7% (PI: 22.7-41.1%), and epimyocardial (GCSEpi.Sys) was 14.3 ± 3.8% (PI: 6.8-21.8%). A significant discrepancy in normal strain values between males and females was observed. Men had lower mean values and lower reference limits for all strain parameters. Furthermore, GLS and GCS changed differently with age in males and females. Finally, regional LS decreased from the apical to the basal LV region in both sexes, and regional CS varied significantly by LV segment.

CONCLUSION

In this study, we reported age- and sex-based reference ranges of layer-specific GLS and GCS. These reference ranges varied significantly with sex and age.

Layer-specific strain for assessing the effect of naringin on systolic myocardial dysfunction induced by sepsis and its underlying mechanisms

OBJECTIVE

This study aimed to investigate the protective effects of naringin on myocardial deformation and oxidative responses in rats with sepsis-induced myocardial dysfunction (SIMD).

METHODS

Global and segmental layer-specific longitudinal strain (LS) was assessed by speckle tracking echocardiography. Serum levels of creatine kinase, lactate dehydrogenase, superoxide dismutase, and malondialdehyde were measured. The activity of cleaved caspase-3 was determined by immunohistochemistry. Protein expression levels of Kelch-like ECH-related protein 1 (Keap1), nuclear erythroid factor 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) were measured by western blotting.

RESULTS

Naringin inhibited the lipopolysaccharide-induced decrease in global and layer-specific LS of the left ventricle. Naringin also increased superoxide dismutase expression and decreased malondialdehyde, creatine kinase, lactate dehydrogenase, and cleaved caspase-3 expression in rats with SIMD. Furthermore, naringin increased Nrf2 and HO-1 protein expression levels, and decreased Keap1 protein expression levels in rats with SIMD.

CONCLUSION

Layer-specific LS analysis of myocardial function by speckle tracking echocardiography can reflect early changes in myocardial systolic function. Naringin may possess a protective effect through moderating lipopolysaccharide-induced myocardial oxidative stress via the Keap1/Nrf2/HO-1 pathway in rats with SIMD.

Layer-Specific Strain Is Preload Dependent: Comparison between Speckle-Tracking Echocardiography and Cardiac Magnetic Resonance Feature-Tracking

BACKGROUND

Speckle-tracking echocardiographic (STE) imaging and cardiac magnetic resonance feature-tracking (CMR-FT) are novel imaging techniques enabling layer-specific quantification of myocardial deformation. Conventional echocardiographic parameters are load dependent, but few studies have investigated the effects of loading conditions on STE and CMR-FT layer-specific strain and the interchangeability of the two modalities. The aim of this study was to evaluate the effects of acute preload augmentation by saline infusion on STE and CMR-FT longitudinal and circumferential layer-specific strain parameters and their intermodal agreement.

METHODS

A total of 80 subjects, including 41 control subjects (mean age, 40 ± 12 years; 49% men) and 39 patients with cardiac disease (mean age, 47 ± 15 years; 92% men) were examined using STE and CMR-FT layer-specific strain analysis before and after saline infusion (median, 2.0 L) with quantification of transmural global longitudinal strain (GLS), epicardial GLS, endocardial GLS, transmural global circumferential strain (GCS), epicardial GCS, and endocardial GCS in addition to epicardial-endocardial gradients. Bland-Altman plots and Pearson correlation coefficients were used to evaluate agreement between the two modalities across all strain parameters.

RESULTS

Acute saline infusion increased all STE and CMR-FT layer-specific strain parameters in both groups. STE and CMR-FT GLS increased by 1.4 ± 1.5% and 1.5 ± 2.0% (P < .001) in control subjects and by 0.9 ± 1.8% and 0.9 ± 1.9% (P < .001) in patients with cardiac disease. STE and CMR-FT GCS increased by 2.0 ± 2.2% and 1.8 ± 2.3% (P < .001) in control subjects and by 1.8 ± 2.3% and 1.7 ± 3.6% in patients with cardiac disease (P < .001 and P = .03). STE longitudinal strain correlated strongly with corresponding CMR-FT longitudinal strain (GLS, epicardial GLS, and endocardial GLS: r = 0.81, r = 0.82, and r = 0.81, respectively) despite poor intermodal agreement (bias ± limits of agreement, -2.84 ± 4.06%, 0.16 ± 3.68%, and 2.33 ± 3.52%, respectively) whereas GCS, epicardial GCS, and endocardial GCS correlated weakly between the two modalities (r = 0.28, r = 0.19, and r = 0.34, respectively) and displayed poor intermodal agreement (bias ± limits of agreement, -1.33 ± 6.86%, 4.43 ± 6.49%, and -9.92 ± 8.55%, respectively).

CONCLUSIONS

STE and CMR-FT longitudinal and circumferential layer-specific strain parameters are preload dependent in both control subjects and patients with cardiac disease. STE and CMR-FT longitudinal layer-specific strain parameters are strongly correlated, whereas circumferential layer-specific strain parameters are weakly correlated. STE and CMR-FT longitudinal and circumferential strain should not be used interchangeably, because of poor intermodal agreement.

Layer-specific strain in patients with heart failure using cardiovascular magnetic resonance: not all layers are the same

BACKGROUND

Global longitudinal strain (GLS), most commonly measured at the endocardium, has been shown to be superior to left ventricular (LV) ejection fraction (LVEF) for the identification of systolic dysfunction and prediction of outcomes in heart failure (HF). We hypothesized that strains measured at different myocardial layers (endocardium = ENDO, epicardium = EPI, average = AVE) will have distinct diagnostic and predictive performance for patients with HF.

METHODS

Layer-specific GLS, layer-specific global circumferential strain (GCS) and global radial strain (GRS) were evaluated by cardiovascular magnetic resonance imaging (CMR) feature tracking in the Alberta HEART study. A total of 453 subjects consisted of healthy controls (controls, n = 77), at-risk for HF (at-risk, n = 143), HF with preserved ejection fraction (HFpEF, n = 87), HF with mid-range ejection fraction (HFmrEF, n = 88) and HF with reduced ejection fraction (HFrEF, n = 58). For outcomes analysis, CMR-derived imaging parameters were adjusted with a base model that included age and N-terminal prohormone of b-type natriuretic peptide (NT-proBNP) to test their independent association with 5-year all-cause mortality.

RESULTS

GLS_EPI distinguished all groups with preserved LVEF (controls - 16.5 ± 2.4% vs. at-risk - 15.5 ± 2.7% vs. HFpEF - 14.1 ± 3.0%, p < 0.001) while GLS_ENDO and all GCS (all layers) were similar among these groups. GRS was reduced in HFpEF (41.1 ± 13.8% versus 48.9 ± 10.7% in controls, p < 0.001) and the difference between GLS_EPI and GLS_ENDO were significantly larger in HFpEF as compared to controls. Within the preserved LVEF groups, reduced GRS and GLS_EPI were significantly associated with increased LV mass (LVM) and LVM/LV end-diastolic volume EDV (concentricity). In multivariable analysis, only GLS_AVE and GRS predicted 5-year all-cause mortality (all ps < 0.05), with the strongest association with 5-year all-cause mortality by Akaike Information Criterion analysis and significant incremental value for outcomes prediction beyond LVEF or GLS_ENDO by the likelihood ratio test.

CONCLUSION

Global strains measured on endocardium, epicardium or averaged across the wall thickness are not equivalent for the identification of systolic dysfunction or outcomes prediction in HF. The endocardium-specific strains were shown to have poorest all-around performance. GLS_AVE and GRS were the only CMR parameters to be significantly associated with 5-year all-cause mortality in multivariable analysis. GLS_EPI and GRS, as well as the difference in endocardial and epicardial strains, were sensitive to systolic dysfunction among HF patients with normal LVEF (> 55%), in whom lower strains were associated with increased concentricity.

Strain Imaging in Cardio-Oncology

Echocardiographic imaging is crucial for patient management during cardiotoxic cancer therapy. Left ventricular ejection fraction is the most commonly used parameter for identifying left ventricular dysfunction. However, it lacks sensitivity to detect subclinical changes in cardiac function due to cardiotoxic treatment. Global longitudinal strain (GLS) is the best studied strain parameter with established diagnostic and prognostic value. Multiple studies have demonstrated changes in GLS as an early marker of cardiotoxicity. This document serves as a primer to help clinicians in the acquisition and interpretation of strain in cardio-oncology. Cases with embedded videos illustrate a step-by-step approach to obtaining GLS measurements and common pitfalls to avoid. The document includes a concise summary of the indications of GLS in cardio-oncology and its role in guiding oncological therapy. Practical approaches on how to implement strain in the echo laboratory with guidance on training and quality assurance are also discussed.

Left atrial speckle tracking echocardiography in clinically healthy dogs: Variability and prediction intervals

Left atrial (LA) speckle tracking echocardiography (STE) provides indices of LA deformation such as strain and strain rate. These variables offer useful clinical information in human and canine patients with cardiac disease. At present, reference ranges for LA STE variables in dogs are scarcely established and, due to variability among centers, they cannot be accepted worldwide. The present study aimed to provide normal ranges for LA strain and strain rate variables in clinically healthy dogs, and to evaluate the effect of clinical parameters such as bodyweight. Eighty clinically healthy dogs served as the study population. Left atrial STE was feasible in all dogs and agreement within and between observers was clinically acceptable for most of the variables, in particular strain variables. Age, sex, and heart rate did not affect LA STE. Bodyweight was negatively correlated with strain variables and positively correlated with diastolic strain rate variables and the relationship was allometric. Bodyweight-based vendor-dependent prediction intervals for LA STE variables in clinically healthy dogs could aid the evaluation of LA function in clinical practice.

Experimental Research on the Evaluation of Left Ventricular Function by Layered Speckle Tracking in a Constrictive Pericarditis Rat Model

OBJECTIVES

In animal models with constrictive pericarditis (CP), detecting the function of cardiac systole by conventional noninvasive ultrasound is a challenge. We aimed to detect cardiac dysfunction in rat models with CP in the early stage by layered speckle tracking.

METHODS

We compared a rat CP model (n = 23, injected with a solution of 1-mg/mL lipopolysaccharides [0.5 mL] and a 10% talc suspension [0.5 mL]) with a control group (n = 20, no injection). After 8 weeks, conventional echocardiography and layered speckle tracking were used to assess the left ventricular structures and functions in the groups.

RESULTS

The global circumferential strain (CS) and longitudinal strain (LS) were decreased in the CP group (P < .05). The CS of the epicardial and middle layers in the CP group was decreased (P < .05), but the endocardial layer was not statistically different. The LS of the epicardial layer was decreased (P < .05), but the middle and endocardial layers were not statistically different. The global free-wall and septal-wall CS of the CP group was decreased (P < .05), mainly due to the decrease of CS of the epicardial and middle layers. The global free-wall LS of the CP group was decreased (P < .05), mainly due to the decrease of LS of the epicardial and middle layers. There were no significant differences between the groups in global LS of the septal wall.

CONCLUSIONS

In the early stage of CP, subepicardial myocardial damage precedes that of the subendocardial myocardium, and free-wall damage precedes that of the septal wall.

Prominent Longitudinal Strain Reduction of Basal Left Ventricular Segments in Patients With Coronavirus Disease-19

BACKGROUND

Coronavirus disease-19 (COVID-19) has been associated with overt and subclinical myocardial dysfunction. We observed a recurring pattern of reduced basal left ventricular (LV) longitudinal strain on speckle-tracking echocardiography in hospitalized patients with COVID-19 and subsequently aimed to identify characteristics of affected patients. We hypothesized that patients with COVID-19 with reduced basal LV strain would demonstrate elevated cardiac biomarkers.

METHODS AND RESULT

Eighty-one consecutive patients with COVID-19 underwent speckle-tracking echocardiography. Those with poor quality speckle-tracking echocardiography (n = 2) or a known LV ejection fraction of <50% (n = 4) were excluded. Patients with an absolute value basal longitudinal strain of <13.9% (2 standard deviations below normal) were designated as cases (n = 39); those with a basal longitudinal strain of ≥13.9% were designated as controls (n = 36). Demographics and clinical variables were compared. Of 75 included patients (mean age 62 ± 14 years, 41% women), 52% had reduced basal strain. Cases had higher body mass index (median 34.1; interquartile range 26.5-37.9 kg/m² vs median 26.9, interquartile range, 24.8-30.0 kg/m², P = .009), and greater proportions of Black (74% vs 36%, P = .0009), hypertensive (79% vs 56%, P = .026), and diabetic patients (44% vs 19%, P = .025) compared with controls. Troponin and N-terminal pro-brain natriuretic peptide levels trended higher in cases, but were not significantly different.

CONCLUSIONS

Reduced basal LV strain is common in patients with COVID-19. Patients with hypertension, diabetes, obesity, and Black race were more likely to have reduced basal strain. Further investigation into the significance of this strain pattern is warranted.

Does layer-specific strain using speckle tracking echocardiography improve the assessment of left ventricular myocardial deformation? A review

An increasing number of studies of left ventricular myocardial deformation have been published. Layer-specific strain using speckle tracking echocardiography to evaluate left ventricular function is not recommended in clinical practice. However, evaluation of myocardial mechanics using longitudinal and circumferential layer-specific strain enables the detection of subclinical impairment of myocardial deformation in various diseases. Unfortunately, normal values for longitudinal and circumferential strain have not been clearly defined. In normal subjects, layer-specific strain decreases from the endocardial to the epicardial layer, and from the apex to the base of the left ventricle. Although various studies have tried to define normal values for each layer in healthy subjects, studies with more subjects are needed. This tool has good reproducibility in terms of intraobserver and interobserver variability, but, as with monolayer strain, it has poor intervendor variability. Efforts that aim for standardization between vendors will be required before widespread use of this technique can be advocated.

Head-to-head comparison of cardiovascular MR feature tracking cine versus acquisition-based deformation strain imaging using myocardial tagging and strain encoding

PURPOSE

Myocardial feature-tracking (FT) deformation imaging is superior for risk stratification compared with volumetric approaches. Because there is no clear recommendation regarding FT postprocessing, we compared different FT-strain analyses with reference standard techniques, including tagging and strain-encoded (SENC) MRI.

METHODS

Feature-tracking software from four different vendors (TomTec, Medis, Circle [CVI], and Neosoft), tagging (Segment), and fastSENC (MyoStrain) were used to determine left ventricular global circumferential strains (GCS) and longitudinal strains (GLS) in 12 healthy volunteers and 12 patients with heart failure. Variability and agreements were assessed using intraclass correlation coefficients for absolute agreement (ICCa) and consistency (ICCc) as well as Pearson correlation coefficients.

RESULTS

For FT-GCS, consistency was excellent comparing different FT vendors (ICCc = 0.84-0.97, r = 0.86-0.95) and in comparison to fast SENC (ICCc = 0.78-0.89, r = 0.73-0.81). FT-GCS consistency was excellent compared with tagging (ICCc = 0.79-0.85, r = 0.74-0.77) except for TomTec (ICCc = 0.68, r = 0.72). Absolute FT-GCS agreements among FT vendors were highest for CVI and Medis (ICCa = 0.96) and lowest for TomTec and Neosoft (ICCa = 0.32). Similarly, absolute FT-GCS agreements were excellent for CVI and Medis compared with both tagging and fast SENC (ICCa = 0.84-0.88), good to excellent for Neosoft (ICCa = 0.77 and 0.64), and lowest for TomTec (ICCa = 0.41 and 0.47). For FT-GLS, consistency was excellent (ICCc ≥ 0.86, r ≥ 0.76). Absolute agreements among FT vendors were excellent (ICCa = 0.91-0.93) or good to excellent for TomTec (ICCa = 0.69-0.85). Absolute agreements (ICCa) were good (CVI 0.70, Medis 0.60) and fair (TomTec 0.41, Neosoft 0.59) compared with tagging, but excellent compared with fast SENC (ICCa = 0.77-0.90).

CONCLUSION

Although absolute agreements differ depending on deformation assessment approaches, consistency and correlation are consistently high regardless of the method chosen, thus indicating reliable strain assessment. Further standardisation and introduction of uniform references is warranted for routine clinical implementation.

Echocardiographic reference ranges for normal left ventricular layer-specific strain: results from the EACVI NORRE study

AIMS

To obtain the normal range for 2D echocardiographic (2DE) measurements of left ventricular (LV) layer-specific strain from a large group of healthy volunteers of both genders over a wide range of ages.

METHODS AND RESULTS

A total of 287 (109 men, mean age: 46 ± 14 years) healthy subjects were enrolled at 22 collaborating institutions of the EACVI Normal Reference Ranges for Echocardiography (NORRE) study. Layer-specific strain was analysed from the apical two-, three-, and four-chamber views using 2DE software. The lowest values of layer-specific strain calculated as ±1.96 standard deviations from the mean were -15.0% in men and -15.6% in women for epicardial strain, -16.8% and -17.7% for mid-myocardial strain, and -18.7% and -19.9% for endocardial strain, respectively. Basal-epicardial and mid-myocardial strain decreased with age in women (epicardial; P = 0.008, mid-myocardial; P = 0.003) and correlated with age (epicardial; r = -0.20, P = 0.007, mid-myocardial; r = -0.21, P = 0.006, endocardial; r = -0.23, P = 0.002), whereas apical-epicardial, mid-myocardial strain increased with the age in women (epicardial; P = 0.006, mid-myocardial; P = 0.03) and correlated with age (epicardial; r = 0.16, P = 0.04). End/Epi ratio at the apex was higher than at the middle and basal levels of LV in men (apex; 1.6 ± 0.2, middle; 1.2 ± 0.1, base 1.1 ± 0.1) and women (apex; 1.6 ± 0.1, middle; 1.1 ± 0.1, base 1.2 ± 0.1).

CONCLUSION

The NORRE study provides useful 2DE reference ranges for novel indices of layer-specific strain.

Speckle tracking echocardiography in a patient with viral myocarditis and acute myocardial infarction

The present case of a patient with acute myocarditis with preserved left ventricular (LV) ejection fraction at the acute stage illustrates the obvious impairment of circumferential and rotational deformation, which can be documented by speckle tracking echocardiography. Thus, qualitative patterns of LV twist, radial strain, and circumferential layer strain, might be a new approach to detect acute myocarditis. The early diagnosis of acute myocarditis by echocardiography is important because of the considerable risk of cardiovascular morbidity as documented by the occurrence of an acute myocardial infarction presumably induced by inflammatory process in this case. <Learning objective: The compound of myocardial deformations caused by left ventricular subendomyocardial and subepimyocardial fibers may be a crucial diagnostic target in cardiac diseases. The predominant involvement of viral myocarditis of the outer myocardial layers might induce impairment of circumferential and rotational deformation, which can potentially serve as a new diagnostic key by echocardiography. In contrast, left ventricular ejection fraction and longitudinal deformation are often observed within normal ranges in patients with acute myocarditis. Acute myocardial infarction as a major cardiac event in acute stage of myocarditis causes completely different deformation patterns, mainly by the predominant involvement of the inner myocardial layers inducing severe pathologies of territorial longitudinal deformation. Patients with suspected acute myocarditis and abnormal findings of circumferential and rotational deformation should undergo additional diagnostic procedures as cardiac magnetic resonance and myocardial biopsy to confirm the diagnosis.>.