Transmural Strain Gradient Research Articles

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. MethodsWe 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. ResultsƐ 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. ConclusionsThe 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.

The role transmural strain gradient in assessment of functionally single ventricle contractility

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The funds of the Ministry of Education and Science. Background Cardiac imaging in patients with FSV (functionally single ventricle) underwent the Fontan procedure is a challenge. One of the most difficult issue to be resolved in FSV patients is myocardial contractility. Thus, we sought for deformation parameters analysis by STE (Speckle Tracing Echocardiography), for haemodynamic and structural reason. We incorporated a novel STE (Speckle Tracing Echocardiography) parameter– TG (transmural strain gradient) representing the difference in strain between subendocardial and subepicardial layer to assess FSV contractile reserve. The role of TG in assessment of FSV after Fontan palliation has not been evaluated yet. Purpose The study aimed to introduce/evaluate transmural longitudinal strain gradient (TG) at rest and during exercise as marker of FSV contractility and exercise performace. Methods The group of 37 patients with FSV after Fontan palliation were enrolled in our study at least 12 months after Fontan operation and in sinus rhythm on ECG. We performed an transthoracic echocardiography at rest and during exercise on a semi-supine cycle ergometer. The apical-chamber views were registered for subsequent post-processing analysis. Due to heterogeneous FSV morphology and primary defects as well as accompanying intraventricular septum segments malformation in majority of cases, we decided to measure and analyse FSV free wall longitudinal strain only. The values of layer-specific: subendocardial and subepicardial longitudinal free wall systolic strain were assessed and the gradient between them was calculated. The TG at rest and during exercise were compared with the cardiopulmonary exercise test results, NYHA class, FSV systolic function studied by CMR (Cardiac Magnetic Resonance) and NT-proBNP concentration. Results The values of TG at rest and during exercise correlated with peak oxygen uptake during the cardio-pulmonary exercise test (p = ,012 for TG at rest, p = ,031). TG during exercise was negatively correlated with CMR-derived ejection fraction (p = ,031) . There was no relationship between TG and NYHA-class and NT-proBNP. Conclusion(s) TG is a promising parameter for FSV contractility assessment. Our preliminary study suggests that it can complete traditional imaging technics and derived parameters. TG is highly associated to exercise capacity. However, utility of TG requires further investigation.

Features of left ventricle longitudinal strain in children from one to five years old, born with low, very low, and extremely low body weight

Purpose. The study assessed left ventricle longitudinal strain of the endocardial, middle, and epicardial layers in children from one to five years old, born with low, very low, and extremely low body weight.Material and methods. The study was performed in 204 children aged from one to five years; of these, 53 children were prematurely born late in pregnancy, 103 children were born very preterm, and 48 children were born healthy and full-term. The left ventricle longitudinal strain of the endocardial, middle, and epicardial layers was assessed off-line using the Speckle Tracking Imaging-2D Strain technology.Results. Disturbance of the transmural gradient strain of left ventricle wall were detected in 11.32% of prematurely born late in pregnancy children and in 16.5% of very preterm children. A decrease of left ventricle segments strain was registered in 33.96% of children prematurely born late in pregnancy and in 18.44% very preterm children. In children of the same age, born healthy and full-term, transmural wall gradient disturbances and decrease of strain in left ventricle segments were not observed. In children prematurely born late in pregnancy, the disturbance of the transmural strain gradient of left ventricle and the decrease of strain in left ventricle segments are not associated with left ventricle remodeling.Conclusion. The development of the cardiovascular system in children of early and preschool age, born prematurely with low, very low, and extremely low body weight, is characterized by disturbances in the transmural strain gradient of left ventricle wall, due to the processes of postnatal growth and development of the child’s heart, which requires monitoring on an outpatient basis in polyclinic in childhood — by a pediatric cardiologist and a pediatrician, and in adulthood — by a cardiologist and therapist.

Evaluation of left ventricular systolic function in patients with systemic lupus erythematosus using ultrasonic layer-specific strain technology and its association with cardiovascular events: a long-term follow-up study

BackgroundSystemic lupus erythematosus (SLE) is a multisystem, autoimmune disease with potential cardiovascular involvement. Layer-specific strain (LSS) analysis is a new method that allows early detection of subtle left ventricular (LV) systolic dysfunction. The aim of this study was to evaluate LV systolic function in patients with SLE using conventional echocardiographic measurements and longitudinal strain (LS) and circumferential strain (CS) by LSS. Furthermore, the association between echocardiographic parameters and the occurrence of cardiovascular events was assessed.MethodsA total of 162 patients with SLE (the SLE group) who underwent a dedicated multidisciplinary assessment, including echocardiography, were analyzed at the time of their first visits. The control group consisted of 68 age- and sex-matched healthy subjects. LS and CS on endocardial, mid-myocardial, and epicardial layers at 17 cardiac segments were measured. Transmural strain gradient was calculated as the differences in systolic strain between the endocardial and epicardial layers.ResultsCompared with control subjects, patients with SLE had significantly lower LV ejection fraction, LS, and CS values in all layers (P < 0.05); LV LS and CS gradient were all lower than control subjects (P < 0.05). During a median follow-up period of 83 months (interquartile range: 64–95 months), 59 patients (36.4%) developed cardiovascular events. Using multivariate Cox regression analysis, we found that LV endocardial LS (hazard ratio, 1.014; 95% CI, 1.002–1.035; P = 0.025) and CS (hazard ratio, 1.051; 95% CI, 1.027–1.077; P < 0.001) demonstrated independent associations with cardiovascular events; whereas LV ejection fraction was not significantly associated with cardiovascular events. The Kaplan–Meier survival curves showed that patients with SLE with lower LV endocardial LS and CS (based on the cutoff values of -21.5% and -29.0%, respectively) experienced higher cumulative rates of cardiovascular events compared with those with higher LV endocardial LS and CS.ConclusionsIn patients with SLE, LV systolic function measured by LV endocardial LS and CS were significantly lower than that of the control group and were associated with cardiovascular events, potentially representing a new technology to improve risk stratification in these patients

Myocardial strain measured via two-dimensional speckle-tracking echocardiography in a family diagnosed with arrhythmogenic left ventricular cardiomyopathy

BackgroundArrhythmogenic cardiomyopathy is a myocardial disorder characterized by ventricular arrhythmias, right and/or left ventricular involvement, and fibrofatty infiltrations in the myocardium. We report a family diagnosed with arrhythmogenic left ventricular cardiomyopathy (ALVC) and depict their echocardiographic characteristics.Methods and resultsFifteen family members were divided into three groups based on whether they carried the TMEM43 mutation and had been diagnosed with ALVC. Eight of them had TMEM43 mutations, and four were diagnosed with ALVC according to the Padua criteria. Only the proband experienced sudden cardiac death and had a dilated left ventricle. Left ventricular ejection fraction was reduced in two patients; however, left ventricular global longitudinal strain was depressed in three patients. Low QRS voltages in limb leads were evident in three patients, and five patients had frequent ventricular premature contractions. Late gadolinium enhancement was evident in three patients. Left ventricular layer-specific strain showed that the transmural strain gradient ratio was increased in patients diagnosed with ALVC, and it was elevated in the genotype-positive and phenotype-negative groups compared with healthy individuals.ConclusionGlobal left ventricular longitudinal strain better evaluated left ventricular function than left ventricular ejection fraction. The transmural strain gradient ratio was elevated in patients diagnosed with ALVC, suggesting that it was useful for the evaluation of ALVC.

Marked Disparity in Regional and Transmural Cardiac Mechanics in the Athlete’s Heart

Regional heterogeneity of the human heart plays an important role in left ventricular (LV) and right ventricular (RV) function and may contribute to enhanced myocardial efficiency in the athlete's heart. This study comprehensively characterized regional and transmural myocardial tissue deformation (strain) in recreationally active (RA) and endurance-trained (ET) men to determine if regional nonuniformity evolves alongside morphological adaptations associated with endurance training. Echocardiography was used to measure LV and RV global, regional (apical, mid, basal) and transmural (endocardial, epicardial) longitudinal strain in 30 endurance-trained (ET) (age, 31 ± 2 yr; body mass index, 23.1 ± 0.5 kg·m; V˙O2peak, 60.2 ± 6.5 mL·kg·min) and 30 RA (age: 29 ± 2 yr; body mass index, 23.4 ± 0.4 kg·m; V˙O2peak: 42.6 ± 4.6 mL·kg·min). Nonuniformity was characterized using apex-to-base and transmural (endocardial-to-epicardial) strain gradients. Global longitudinal strain was similar in ET and RA in the left (-17.4% ± 0.4% vs -17.8% ± 0.5%, P = 0.662) and right ventricle (-25.8% ± 0.8% vs 26.4% ± 1.0%, P = 0.717). The apex-to-base strain gradient was greater in ET than RA in the left (-6.5% ± 0.7% vs -2.7% ± 0.8%, P = 0.001) and right ventricle (-9.6% ± 1.8% vs -3.0% ± 1.6%, P = 0.010). The LV transmural strain gradient was greater than RV in both groups, but similar in ET and RA (-4.7% ± 0.2% vs -4.7% ± 0.2%, P = 0.850), whereas RV transmural strain gradient was greater in ET than RA (-3.4% ± 0.3% vs -1.6% ± 0.4%, P = 0.003). RV apex-to-base and transmural strain gradients correlated with RV end-diastolic area (R = 0.536 & 0.555, respectively, P < 0.01) and V˙O2peak (R = 0.415 & 0.677, respectively, P < 0.01). Transmural nonuniformity is more pronounced in the left ventricle than the RV free wall; however, RV functional nonuniformity develops markedly after endurance training. Differences in myocardial architecture and exercise-induced wall stress in the left and right ventricles are possible explanations for the marked functional nonuniformity throughout the myocardium and in response to endurance exercise training.

Intact myocardial preparations reveal intrinsic transmural heterogeneity in cardiac mechanics

Determining transmural mechanical properties in the heart provides a foundation to understand physiological and pathophysiological cardiac mechanics. Although work on mechanical characterisation has begun in isolated cells and permeabilised samples, the mechanical profile of living individual cardiac layers has not been examined. Myocardial slices are 300 μm-thin sections of heart tissue with preserved cellular stoichiometry, extracellular matrix, and structural architecture. This allows for cardiac mechanics assays in the context of an intact in vitro organotypic preparation. In slices obtained from the subendocardium, midmyocardium and subepicardium of rats, a distinct pattern in transmural contractility is found that is different from that observed in other models. Slices from the epicardium and midmyocardium had a higher active tension and passive tension than the endocardium upon stretch. Differences in total myocyte area coverage, and aspect ratio between layers underlined the functional readouts, while no differences were found in total sarcomeric protein and phosphoprotein between layers. Such intrinsic heterogeneity may orchestrate the normal pumping of the heart in the presence of transmural strain and sarcomere length gradients in the in vivo heart.

P208 Abnormal coronary flow reserve assessed with stress echocardiography induces a reduction in transmural strain gradient and an increase in heterogeneous myocardial electrical activation

Abstract OnBehalf Echo Lab INC Background The integrated quadruple stress echo (IQ-SE) is a state-of-the-art protocol that expands the risk stratification potential of SE. The coronary flow reserve (CFVR) has pronostic implication mainly in the absence of wall motion abnormalities. Longitudinal multilayer strain analysis assesses trasmural strain gradient. The prognostic value of multilayer strain analysis alongside the IQ-SE has not been established. We aim to determine the additive value of multilayer strain analysis during IQ-SE. Methods Prospective observational study. We evaluated one hundred twenty intermediate-high risk patients without obstructive coronary artery disease (mean age 61 ± 12 years, female 43%) with IQ-SE dipyridamole at our institution. Abnormal CFVR was defined as CFVR &amp;lt;2. Multilayer strain analysis and mechanical dispersion, were performed during rest and stress, with an automatic frame-by-frame with speckle tracking. Results The IQ-SE was feasible in all patients. At rest, mean three-dimensional left ventricular ejection fraction (3D LVEF) was 59% (53-62) without wall motion abnormalities. Abnormal CFVR was seen in 38 patients (32%) and reduced left ventricular contractile reserve (LVCR) in 56 patients (46%). Patients with abnormal CFVR, showed a reduction in EndoLS and transmural strain gradient, and an increase in mechanical dispersion and in lung B-lines during stress. No differences were observed in 3D LVEF and LVCR. Conclusions Endocardial ischemia due to microvascular dysfunction leads to a reduction in transmural strain gradient. Adding multilayer strain analysis to IQ-SE might detect myocardial subclinical dysfunction, arrhythmic risk and pulmonary congestion due to microvascular dysfunction. Left ventricular mechanics analysis CVFR &amp;lt;2 (38) CVFR &amp;gt;2 (81) P Rest EpiLS (%) -14.9 ±4.2 -18 ± 3.7 0.001 EndoLS (%) -20.2 ± 5.9 -23.5 ± 4.5 0.001 EndoLS- EpiLS 5.1 (3.8-6.3) 5.4 (4.2-6.3) 0.27 Mechanical Dispersion (ms) 57.7 (42.2-69) 44.2 (35-54) 0.006 Stress EpiLS (%) -17.2 ± 4.8 -20 ± 4.4 0.003 EndoLS (%) -23 ± 6 -26.6 ± 5.7 0.002 EndoLS- EpiLS 5.6 (4.5-6.7) 6.3 (5.4-7.9) 0.01 Mechanical Dispersion (ms) 47 (39.5 - 59) 39 (30-54.6) 0.007 CVFR: coronary flow reserve; EpiLS: Epicardium longitudinal strain; EndoLS: endocardial longitudinal strain; EndoLS- EpiLS: trasmural strain gradient. Abstract P208 Figure. IQ-SE and Multilayer Strain

P678 Late gadolinium enhancement cardiac magnetic resonance and layer-specific longitudinal strain in treatment naive Anderson Fabry disease

Abstract Background In Anderson-Fabry disease (AFD), the accumulation of glycosphingolipids in cardiomyocytes causes inflammation, hypertrophy and interstitial fibrosis which is first limited to the mid-myocardial layers, then spreads to transmural fibrosis. Speckle tracking echocardiography allows the estimation of layer-specific strain, differentiating longitudinal strain (LS) at subendocardium and subepicardium (LSsubendo and LSsubepi, respectively). Purpose To investigate the matching of functional and structural abnormalities in newly diagnosed, never treated AFD patients by comparing multi-layer LS and late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR). Methods Twenty newly diagnosed, never treated AFD patients (age = 37 ± 13 years; F/M =10/10) and 20 healthy controls, matched for age and sex, underwent comprehensive evaluation of target organs and a standard echo-Doppler exam, including assessment of relative diastolic wall thickness (RWT) and left ventricular mass index (LVMI). Left ventricular hypertrophy (LVH) was defined as LVMi &amp;gt; 47 g/m^2.7 in women and &amp;gt;50 g/m^2.7 in men. Speckle tracking echocardiography derived left ventricular transmural global longitudinal strain (GLS), LSsubendo, LSsubepi and LS gradient (LSsubendo - LSsubpepi) were also determined. CMR sequences including assessment of LGE were also performed. Results AFD patients had normal renal function and comparable body mass index, blood pressure, heart rate, ejection fraction and diastolic indices with healthy controls. LVMi (p = 0.006) and RWT (p &amp;lt; 0.02) were greater in AFD patients than in controls. GLS (p = 0.006), LSsubendo (p = 0.005) and LSsubepi (p &amp;lt; 0.001) were lower in AFD patients. By CMR, only four patients (F/M = 3/1), 3 with LVH (75%), exhibited focal LGE, always localized in the midwall. LGE was detected at basal lateral wall in three patients and at the septal insertional points with the right ventricle in the remaining one. AFD patients with LGE had higher LVMi than those without LGE (47.2 ± 11.0 vs. 34.5 ± 11.6 g/m^2.7, p = 0.04). There was no correspondence of LGE with both regional LS and layer specific LS impairment (Figure). However, AFD patients with LGE had higher LS gradient compared to those without LGE (5.8 ± 0.65 vs. 4.8 ± 0.66, p &amp;lt; 0.02). Conclusions Treatment naïve AFD patients show a reduction of longitudinal deformation, which involves both subendocardial and subepicardial layers. Patients with LGE present higher LV mass and increased LS gradient, without a correspondence of LGE with both regional and layer specific LS impairment. Accordingly, this impairment might due to myocardial inflammation occurring in the early disease stages more than to myocardial fibrosis itself. Abstract P678 Figure. Multilayer bull"s eye and LGE-CMR in AFD

Value of layer-specific strain distribution patterns in hypertrophied myocardium from different etiologies

BackgroundIntrinsic myocardial mechanics might have different patterns because of the different etiologies of myocardial hypertrophy. We used layer-specific strain to compare those with aortic stenosis (AS) and hypertrophic cardiomyopathy (HCM) and examined the differences in strain distribution pattern and for their clinical implications. MethodsComprehensive echocardiography was done in 3 groups: 129 with moderate-to-severe AS, 172 consecutive patients with HCM, and 58 healthy controls. Left ventricle (LV) layer-specific deformation parameters were obtained using two-dimensional speckle tracking echocardiography. The transmural strain gradient was defined as the strain difference between subendocardial and subepicardial myocardium. Both diseased groups were further divided based on the median value of transmural strain gradient for the hemodynamics correlation. ResultsCompared with the HCM group, the AS group had more preserved transmural longitudinal strain gradient (4.49 ± 1.3% vs. 3.61 ± 1.2%, p < 0.001), which was not significantly different from that of the healthy controls (4.49 ± 1.3% vs. 4.54 ± 1.0%, p = 0.975). And only in AS group the transmural circumferential strain correlated with myocardium mass index (r = −0.237, p = 0.008), and the hemodynamic profiles (LV ejection fraction and LA pressure) were correlated well with transmural strain gradient, in that the lower subgroup had a significantly lower LV ejection fraction and higher average E/E′. ConclusionsMyocardium hypertrophy from different etiology resulted in different layer-specific strain distribution pattern. The loss of an adequate transmural strain gradient correlated with hemodynamics and might reflect intrinsic myocardial dysfunction.

Ageing Alters Right Ventricular But Not Left Ventricular Myocardial Mechanics

Introduction: Ageing is associated with a progressive stiffening of the pulmonary vasculature that causes an increase in pulmonary vascular resistance and a decrease in compliance. It remains unclear if right ventricular myocardial mechanics adapt in response to age-related remodeling in the pulmonary vasculature. PURPOSE: Accordingly, this study examined global and transmural longitudinal myocardial tissue deformation (strain) in a cohort of healthy young and middle-aged men to characterize age-related changes in myocardial tissue mechanics. METHODS: Two-dimensional echocardiography was used to measure left (LV) and right (RV) ventricular strain in 10 young men (YM; Age: 27 ± 2yr, BMI: 23.2 ± 2.4m2) and 10 middle aged men (MAM; Age: 61 ± 7yr, BMI: 25.9 ± 3.2m2). A transmural strain gradient was calculated as the difference between endocardial and epicardial strain as an index of regional non-uniformity. RESULTS: Systemic blood pressure was similar in young and middle aged men (YM: 118 ± 4mmHg vs MAM: 122 ± 4mmHg, p > 0.05), while echocardiographic estimates of pulmonary blood pressure via the tricuspid regurgitation pressure gradient were greater in middle aged men (YM: 17 ± 4mmHg vs MAM: 25 ± 6mmHg, p 0.05) in young (LV EDV: 118 ± 19mL; RV EDA: 18.3 ± 2.2cm2) and middle aged men (LV EDV: 118 ± 17mL; RV EDA: 17.3 ± 3.8cm2). LV global longitudinal strain (YM: -17.5 ± 1.0% vs MAM: -18.0 ± 1.0%, p > 0.05) was similar in young and middle aged men, while RV global longitudinal strain (YM: -27.3 ± 1.8% vs MAM: -22.5 ± 1.7%, p 0.05) was similar in young and middle aged men, while RV transmural strain gradient (YM: -1.1 ± 0.4% vs MAM: -5.5 ± 0.5%, p<0.01) was higher in middle aged men. CONCLUSION: Ageing was associated with global and regional alterations in RV myocardial mechanics, while LV function was unaltered. Specifically, ageing resulted in a decrease in RV global strain and an increase in transmural non-uniformity (i.e., increased transmural strain gradient). Differences in LV and RV myocardial architecture and age-related changes in the pulmonary vasculature are possible explanations for opposing LV and RV functional remodeling in response to ageing.

Distribution pattern of left-ventricular myocardial strain analyzed by a cine MRI based deformation registration algorithm in healthy Chinese volunteers

The cine magnetic resonance imaging based technique feature tracking-cardiac magnetic resonance (FT-CMR) is emerging as a novel, simple and robust method to evaluate myocardial strain. We investigated the distribution characteristics of left-ventricular myocardial strain using a novel cine MRI based deformation registration algorithm (DRA) in a cohort of healthy Chinese subjects. A total of 130 healthy Chinese subjects were enrolled. Three components of orthogonal strain (radial, circumferential, longitudinal) of the left ventricle were analyzed using DRA on steady-state free precession cine sequence images. A distinct transmural circumferential strain gradient was observed in the left ventricle that showed universal increment from the epicardial to endocardial myocardial wall (epiwall: −15.4 ± 1.9%; midwall: −18.8 ± 2.0%; endowall: −22.3 ± 2.3%, P < 0.001). Longitudinal strain showed a similar trend from epicardial to endocardial layers (epiwall: −16.0 ± 2.9%; midwall: −15.6 ± 2.7%; endowall: −14.8 ± 2.4%, P < 0.001), but radial strain had a very heterogeneous distribution and variation. In the longitudinal direction from the base to the apex of the left ventricle, there was a trend of decreasing peak systolic longitudinal strain (basal: −23.3 ± 4.6%; mid: −13.7 ± 7.3%; apical: −13.2 ± 5.5%; P < 0.001). In conclusion, there are distinct distribution patterns of circumferential and longitudinal strain within the left ventricle in healthy Chinese subjects. These distribution patterns of strain may provide unique profiles for further study in different types of myocardial disease.

Value of Layer-Specific Strains in Hypertrophied Myocardium of Aortic Stenosis from Comparison with Hypertrophy Cardiomyopathy

Intrinsic myocardial mechanics may have different patterns due to different etiologies of myocardial hypertrophy. We used layer-specific strain to compare the hypertrophied myocardium between hypertrophic cardiomyopathy (HCM) and aortic stenosis (AS) individuals. We searched for the differences in strain distribution and clinical implications for these patients. Comprehensive echocardiography were performed in 3 groups of 172 consecutive patients with HCM, 129 participants with moderate to severe AS and 79 healthy controls. Left ventricular (LV) layer-specific deformation parameters were obtained by two-dimensional speckle tracking echocardiography, including longitudinal strain of both sub-endocardial and sub-epicardial myocardium. The transmural strain gradient was defined as the strain difference between sub-endocardial and sub-epicardial myocardium. We further divided AS patients into two subgroups according to the median level of transmural longitudinal strain gradient. In comparison of the layer-specific myocardial deformation parameters between the HCM and AS groups, hypertrophied myocardium from the AS group had better sub-epicardial myocaridial (¬¬-13.5±3.5% vs -11.6±3.5%, p<0.001) and sub-endocardial myocardial longitudinal strain (-18.0±4.4% vs -15.3±4.3%, p<0.001), and higher transmural longitudinal strain gradient (4.5±1.3% vs 3.6±1.2%, p<0.001). Both diseased groups had significantly reduced layer-specific longitudinal strains than the healthy controls (sub-endocardial: -21.20±3.7%, sub-epicardial: -16.7±3.0%, both p <0.001 ). The transmural longitudinal strain gradient of the AS group revealed no significant difference from the healthy controls (4.49±1.3 % vs 4.51±1.0 %, p = 0.996 ), whereas there was significant reduction from the HCM group (3.61±1.2 % vs 4.51±1.0%, p < 0.001). This transmural gradient difference still remained significant after being adjusted for global longitudinal strain, age, gender, LV mass index, and average early mitral filling velocity to early annular velocity ratio (E/E’) (p<0.001) in multivariate analysis. There were no valvular severity differences in the two AS subgroups, but the subgroup with lower transmural longitudinal gradient had significant lower LV ejection fraction (62.8 ± 12.2% vs. 70.4 ± 7.5%, p < 0.001) and higher average E/E’ (20.6 ± 10.7 vs. 15.9 ± 7, p = 0.004). Hypertrophied myocardium in AS patients not only had better longitudinal strain at sub-epicardial and sub-endocardial myocardium, but also presented with more preserved transmural longitudinal strain gradient when compared to those of the HCM group. The loss of preserving adequate transmural longitudinal strain gradient might reflect intrinsic myocardial dysfunction in AS.

Evaluation of left ventricular transmural mechanics after anthracycline chemotherapy in patients with breast cancer by speckle tracking imaging

Objective To evaluate the left ventricular transmural mechanics changes of breast cancer patients between before and after anthracycline chemotherapy by two-dimensional speckle tracking imaging (2D-STI), and to predict early cardiotoxicity caused by anthracycline. Methods Forty-six breast cancer patients with postoperative anthracycline-based chemotherapy were recruited. Echocardiography were performed on all subjects before and at 1, 3 and 6 anthracycline-based chemotherapeutic cycle. Global longitudinal strain(GLS), endocardial longitudinal strain(LS-endo), epicardial longitudinal strain(LS-epi), global radial strain(GRS), endocardial radial strain(RS-endo), epicardial radial strain(RS-epi), global circumferential strain(GCS), endocardial circumferential strain(CS-endo) and epicardial circumferential strain(CS-epi) were assessed by 2D-STI and transmural myocardial strain gradient-longitudinal strain(TMSG-LS), transmural myocardial strain gradient-radial strain(TMSG-RS), transmural myocardial strain gradient-circumferential strain(TMSG-CS) were calculated. Conventional echocardiographic parameters and strain-related parameters before and after chemotherapy were compared. The receiver operating characteristics(ROC)curve was performed to determine sensitivity and specifity of strain parameters for prediction value of cardiotoxicity induced by anthracycline chemotherapy. Results ①After the sixth cycle of anthracycline chemotherapy, 9 patients (16.4%) had developed anthracycline-induced cardiotoxicity, and 37 patients (80.4%) did not meet the criteria for cardiotoxicity. ②There were no significant differences in conventional echocardiography parameters between before and after chemotherapy (P>0.05). Left ventricular ejection fraction (LVEF), fractional shortening (FS) and E/A significantly decreased, but E/e significantly increased after six cycles of chemotherapy (P LS-endo> GLS> LS-epi. Conclusions After three cycles of chemotherapy, the decreases of TMSG-LS, LS-endo, GLS and LS-epi preceded the change of LVEF and other strain parameters, TMSG-LS and LS-endo can accurately and early detect anthracycline chemotherapy-induced cardiotoxicity. Key words: Echocardiography; Breast neoplasms; Anthracyclines; Transmural myocardial strain gradient; Two-dimensional speckle tracking imaging

GW26-e5449 Left Ventricular transmural strain gradient analysis by Layer-specific Strain Imaging

GW26-e5449 Left Ventricular transmural strain gradient analysis by Layer-specific Strain Imaging

PM426 Experimental Validation of Left Ventricular Transmural Strain Gradient with Echocardiographic Velocity Vector Imaging

PM426 Experimental Validation of Left Ventricular Transmural Strain Gradient with Echocardiographic Velocity Vector Imaging

Transmural strain and rotation gradient in survivors of childhood cancers

Subendocardial layer of the ventricle has been shown to be sensitive to anthracycline damage. This study tested the hypothesis that anthracycline therapy for childhood malignancies has differential impact on deformation and rotation of left ventricular (LV) subendocardial and subepicardial layers and hence transmural myocardial strain and rotation gradients. Thirty-two anthracycline-treated survivors of childhood malignancies aged 19.3 ± 5.4 years and 28 controls were studied. Apical four-chamber and parasternal LV short-axis acquisitions at base, papillary muscle level, and apex were analysed for layer-specific myocardial strain and apical and basal rotation and rotational velocities using two-dimensional speckle tracking echocardiography. Transmural strain and rotation gradients were calculated as differences between peak systolic strain and rotation between the inner and outer layers, respectively. Compared with controls, patients had significantly lower transmural circumferential, but not radial or longitudinal, strain gradients (P< 0.05), accounted by the reduced subendocardial circumferential strain, at all three ventricular levels (all P< 0.05). No significant difference in basal transmural rotation gradient was found between patients and controls (P= 0.32). On the other hand, apical rotation, systolic twisting velocity, and diastolic untwisting velocity were reduced preferentially at the subendocardial layer in patients (all P< 0.05), hence accounting for their significantly reduced transmural rotation gradient compared with controls (P< 0.001). The LV ejection fraction correlated inversely with apical transmural circumferential strain gradient (r= -0.39, P= 0.002) and rotation gradient (r= 0.33, P= 0.01). Preferential impairment of subendocardial circumferential deformation and apical rotation with consequential reduction of transmural circumferential strain and rotation gradients occurs in anthracycline-treated survivors of childhood cancers.

Left ventricular strain, rotation, and torsion as markers of acute myocardial ischemia

This study investigates how tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE) describe regional myocardial deformation during controlled reductions of left anterior descending (LAD) coronary artery perfusion pressure. In eight anesthetized pigs, a shunt with constrictor was installed from the brachiocephalic artery to the LAD. Data were obtained with open shunt, followed by four degrees of stenosis (S1-S4) of increasing severity: S1, ∼15%; S2, ∼35%; S3, ∼50%; and S4, ∼60% reductions of LAD perfusion pressure. At each situation, microspheres for perfusion measurements were injected and left ventricular (LV) short- and long-axis cineloops were recorded. In the anterior wall, radial, circumferential, and longitudinal one-layer STE strain, one-layer radial TDI strain, and three-layer radial TDI and STE strain were measured. LV peak mean rotation was measured at six equidistant levels from apex to base (in 7 pigs). LV torsion was calculated from end-systolic mean rotation. With open shunt, three-layer TDI analysis showed a transmural strain gradient with no perfusion gradient. Perfusion, one-layer TDI strain, and strain in the mid- and subendocardium from three-layer TDI were reduced at S2 (P < 0.05). STE strain was not affected until S3 (P < 0.05). Peak mean rotation, increasing toward the apex, decreased at the three apical levels at S4 (P < 0.05). LV torsion did not decrease (P = 0.26). In conclusion, TDI strain detected dysfunction already with minor changes in global hemodynamics, whereas STE strain was first reduced with moderate changes. LV peak mean rotation was not reduced until severe reduction of LAD perfusion pressure, but remained increasingly counterclockwise toward the apex. LV torsion remained unaffected by ischemia.

Imaging three‐dimensional myocardial mechanics using navigator‐gated volumetric spiral cine DENSE MRI

A navigator-gated 3D spiral cine displacement encoding with stimulated echoes (DENSE) pulse sequence for imaging 3D myocardial mechanics was developed. In addition, previously described 2D postprocessing algorithms including phase unwrapping, tissue tracking, and strain tensor calculation for the left ventricle (LV) were extended to 3D. These 3D methods were evaluated in five healthy volunteers, using 2D cine DENSE and historical 3D myocardial tagging as reference standards. With an average scan time of 20.5 ± 5.7 min, 3D data sets with a matrix size of 128 × 128 × 22, voxel size of 2.8 × 2.8 × 5.0 mm(3), and temporal resolution of 32 msec were obtained with displacement encoding in three orthogonal directions. Mean values for end-systolic mid-ventricular mid-wall radial, circumferential, and longitudinal strain were 0.33 ± 0.10, -0.17 ± 0.02, and -0.16 ± 0.02, respectively. Transmural strain gradients were detected in the radial and circumferential directions, reflecting high spatial resolution. Good agreement by linear correlation and Bland-Altman analysis was achieved when comparing normal strains measured by 2D and 3D cine DENSE. Also, the 3D strains, twist, and torsion results obtained by 3D cine DENSE were in good agreement with historical values measured by 3D myocardial tagging.

Experimental validation of left ventricular transmural strain gradient with echocardiographic two-dimensional speckle tracking imaging

To validate intramural strain measured by a speckle tracking imaging (STI) system against that measured by sonomicrometry crystals. In 11 anaesthetized sheep, six sets of three sonomicrometry crystals were implanted in endo-, mid-wall, and epimyocardium on the anterior and lateral walls. Circumferential strain (CS) was calculated at three layers from endo-, mid-wall, and epicardial speckle. Radial strain (RS) was assessed for inner and outer halves of the myocardium. We compared ultrasound-derived strain measurements against those by sonomicrometry at baseline and during pharmacological stress and coronary occlusion. Intraclass correlation coefficients at baseline and during coronary occlusion were as follows: endocardial CS 0.80, 0.97; mid-wall CS 0.58, 0.89; epicardial CS 0.71, 0.81; endocardial RS 0.50, 0.78; epicardial RS 0.35, 0.83; and total RS 0.33, 0.71; respectively. At baseline, endocardial strains were higher than mid-wall and epicardial strains, resulting in an inner/outer wall RS gradient and inner/mid/outer wall CS gradients. Ischaemia caused significant reduction in all strains and disappearance of the strain gradient. A newly developed STI system can accurately assess the intramural heterogeneity of CS distribution in normal and ischaemic myocardial segments and has the potential to become a non-invasive bedside tool for characterizing myocardial strain gradient.