Cardiac magnetic resonance-feature tracking technique can assess cardiac function and prognosis in patients with myocardial amyloidosis / 南方医科大学学报

OBJECTIVE@#To quantitatively assess cardiac functions in patients with cardiac amyloidosis (CA) and hypertrophic cardiomyopathy (HCM) using cardiac magnetic resonance-feature tracking (CMR-FT) technique and evaluate the prognostic value of CMR-FT in patients with CA.@*METHODS@#We retrospectively collected the data from 31 CA patients with systemic amyloidosis confirmed by Congo red staining and serum immunohistochemistry after extracardiac tissue biopsy undergoing CMR at our hospital from March, 2013 to June, 2021.Thirty-one age and gender matched patients with asymmetric left ventricular wall hypertrophy and 31 healthy individuals without organic or functional heart disease served as the controls.Radial, circumferential and longitudinal strains and strain rates of the left ventricle at the global level and in each myocardial segment (basal, middle and apical) were obtained with CMR-FT technique and compared among the 3 groups.The predictive value of myocardial strains and strain rates for all-cause mortality in CA patients was analyzed using a stepwise COX regression model.@*RESULTS@#The left ventricular volume, myocardial mass, ejection fraction and cardiac output differed significantly among the groups (P < 0.05).Except for apical longitudinal strain, the global and segmental strains were all significantly lower in CA group than in HCM group (P < 0.05).The global and segmental strains were all significantly lower in CA group than in the healthy individuals (P < 0.05).The basal strain rates in the 3 directions were significantly lower in CA group than in the healthy individuals (P < 0.05), but the difference in apical strain rates was not statistically significant between the two groups.Multivariate stepwise COX analysis showed that troponin T (HR=1.05, 95%CI: 1.01-1.10, P=0.017) and middle peak diastolic circumferential strain rate (HR=6.87, 95%CI: 1.52-31.06, P=0.012) were strong predictors of death in CA patients.@*CONCLUSION@#Strain and strain rate parameters derived from CMR-FT based on cine sequences are new noninvasive imaging markers for assessing cardiac impairment in CA and cardiac function changes in HCM, and provide independent predictive information for all-cause mortality in CA patients.

Study of nonlinear viscoelastic mechanical properties of degenerated intervertebral discs / Estudio de las propiedades mecánicas viscoelásticas no lineales de discos intervertebrales degenerados

SUMMARY: Biomechanical factors are important factors in inducing intervertebral disc degeneration, in this paper, the nonlinear viscoelastic mechanical properties of degenerated intervertebral discs were analyzed experimentally. Firstly, the loading and unloading curves of intervertebral discs before and after degeneration at different strain rates were compared to analyze the changes of their apparent viscoelastic mechanical properties; The internal stress/strain distribution of the disc before and after degeneration was then tested by combining digital image technology and fiber grating technology. The results show that the intervertebral disc is strain-rate- dependent whether before or after degeneration; The modulus of elasticity and peak stress of the degenerated disc are significantly reduced, with the modulus of elasticity dropping to 50 % of the normal value and the peak stress decreasing by about 55 %; Degeneration will not change the distribution of the overall internal displacement of the intervertebral disc, but has a greater impact on the superficial and middle AF; The stress in the center of the nucleus pulposus decreases, and the stress in the outer AF increases after degeneration. Degeneration has a great impact on the nonlinear viscoelastic mechanical properties of intervertebral disc, which has reference value for the mechanism, treatment and prevention of clinical degenerative diseases.

RESUMEN: Los factores biomecánicos son importantes en la inducción de la degeneración del disco intervertebral. En este estudio se analizaron experimentalmente las propiedades mecánicas viscoelásticas no lineales de los discos intervertebrales degenerados. En primer lugar se compararon las curvas de carga y descarga de los discos intervertebrales, antes y después de la degeneración, a diferentes velocidades de deformación para analizar los cambios aparentes de sus propiedades mecánicas viscoelásticas. La distribución interna de tensión/deformación del disco antes y después de la degeneración se probó luego combinando tecnología de imagen digital y tecnología de rejilla de fibra. Los resultados mostraron que el disco intervertebral depende de la velocidad de deformación antes o después de la degeneración; El módulo de elasticidad y la tensión máxima del disco degenerado se reducen significativamente, cayendo el módulo de elasticidad al 50 % del valor normal y la tensión máxima disminuyendo en aproximadamente un 55 %; La degeneración no cambiará la distribución del desplazamiento interno general del disco intervertebral, pero tiene un mayor impacto en la FA superficial y media; El estrés en el centro del núcleo pulposo disminuye y el estrés en el FA externo aumenta después de la degeneración. La degeneración tiene un gran impacto en las propiedades mecánicas viscoelásticas no lineales del disco intervertebral, que tiene valor de referencia para el mecanismo, tratamiento y prevención de enfermedades clínicas degenerativas.

Compression Properties of Fat Layer under Impact Loading / 医用生物力学

Objective To study dynamic compression performance of adipose tissues, so as to further reveal the damage mechanism, and provide references for medical treatment.Methods Based on the improved split Hopkinson pressure bar (SHPB) experimental device, the adipose tissue dynamic compression experiment was conducted. The stress-strain curves of adipose tissues at different strain rates were obtained. Then the numerical model of SHPB was established, and the experimental process was simulated and analyzed. The numerical simulation for penetration process of 32 mm diameter rubber non-lethal projectile into the simulated target in human abdomen was carried out.Results Adipose tissues had a noticeable strain rate effect. The stress-strain curves at two high strain rates were approximately straight lines. The slope was similar, and the elastic modulus was 3.25 MPa, which was about 6 times of that under a quasi-static state. The simulation curves of fat SHPB were consistent with the experimental curves, which verified correctness of the constitutive model. In the process of non-lethal projectile penetrating human abdomen, an annular convex area similar to water wave appeared on skin surface, and the fat layer absorbed about 67% of the impact kinetic energy.Conclusions The experimental data of adipose tissues are very accurate. Numerical simulation can reproduce the penetration process well, and provide references for studying the damaging effect of non-lethal weapons on human body.

A Continuum Constitutive Model of skeletal Muscle at Variable Strain Rate / 医用生物力学

Objective Aiming at the problem that mechanical properties for the continuum of muscle tissues cannot be considered in active and passive behaviors of different structurally coupled muscles, a method of passive and active coupling in the same constitutive equation was proposed to construct ahyperelastic active and passive constitutive model of skeletal muscle continuum. Methods In order to calibrate parameters of the passive constitutive model, the uniaxial tensile experiment method and conditions were given, and through theoretical derivation, the specific method of using experimental data to solve the passive model parameters was introduced. In order to verify effectiveness of the active model, the model was verified with an example. Results The curves predicted by the model were in good agreement with the experimental output stress-stretch ratio curves. At the same strain, the maximum error of passive stress and total stress were only 20 kPa and 40 kPa. Conclusions The continuum hyperelastic constitutive model can better simulate active and passive behavior of skeletal muscles, which is beneficial for modeling and simulation of human muscles in further study.

Numerical Model for Calculating Active and Passive Properties of Muscles with High Strain Rate / 医用生物力学

Objective On the basis of explicit dynamics calculation theory, a numerical model for calculating active and passive properties of muscles with high strain rate was proposed. Methods In the process of calculating the motion equation of muscle element with high strain rate, Hill’s three-factor muscle model with high strain rate was introduced into the noda force formula to modify the node force in each time step. Results As Hill’s three-factor muscle model was introduced in numerical calculation, the muscle element had the passive characteristics of the general structural constitutive model and its proprietary active characteristics. Conclusions The research findings will contribute to numerical calculation for dynamic response and damage of muscles with high strain rate.

Evaluation of left ventricular diastolic function by strain rate parameters in patients with coronary artery disease without regional wall motion abnormalities / 中华超声影像学杂志

Objective:To investigate the value of early diastolic strain rate (e′SR) and peak value of early diastolic velocity (E) to e′SR (E/e′SR) in predicting the severity of coronary lesions in patients with coronary artery disease (CAD) without regional wall motion abnormalities (RWMA) and with preserved left ventricular ejection fraction (LVEF).Methods:A selection of 70 patients with CAD without RWMA and with preserved LVEF (>50%) admitted to Zhengzhou University People′s Hospital from October 2020 to March 2021 were collected and divided into two groups according to the Gensini score method: low group with a score<34 and high group with a score≥34. Another 30 healthy volunteers with matching gender and age at the same period were selected as the control group. Cardiac structural parameters left atrium diameter (LAD), left ventricular end diastolic diameter (LVEDd), left ventricular end systolic diameter (LVEDs), interventricular septum diastolic diameter (IVST), left atrial volume (LAV), E, peak value of late diastolic velocity (A) of mitral inflow, peak value of early diatolic tissue Doppler velocity of septal and lateral walls of mitral annulus and LVEF were routinely measured. Left atrial volume index (LAVI), mean of peak value of early diatolic tissue Doppler velocity of septal and lateral walls of mitral annulus (e′), E/e′were calculated. Speckle tracking imaging (STI) technique was used to collect systolic left ventricular global longitudinal strain (GLS) and e′SR, E/e′SR was calculated. The differences in each parameter among the three groups were compared. The ROC curve was used to obtain the best cut-off values of e′SR and E/e′SR for predicting the severity of coronary lesions in CAD patients, respectively, and the corresponding sensitivity and specificity were obtained, respectively.Results:Compared with the control group, LAV and LAVI were increased in the high group (all P<0.05). Compared with the control and the low group, e′ was decreased and E/e′ was increased in the high group (all P<0.05). Compared with the control group, e′SR and GLS were decreased and E/e′SR were increased in the high and low groups (all P<0.05). Compared with the low group, e′SR and GLS were decreased and E/e′SR was increased in the high group (all P<0.05). ROC curve analysis showed that the maximum area of E/e′SR under the curve was 0.717. When the Youden index was maximum, its best cut-off value was 0.75 m, and corresponding sensitivity and specificity were 60.0% and 85.7%, respectively. The maximum area under the e′SR curve was 0.785. When the Youden index was maximum, its best cut-off value was 1.12 s -1, and the corresponding sensitivity and specificity were 85.7% and 68.6%, respectively. Conclusions:For CAD patients without significant RWMA and with preserved LVEF, left ventricular diastolic and systolic function may be impaired to varying degrees, manifesting as decreased e′SR, increased E/e′SR, decreased GLS. The parameters of diastolic strain rate are a reliable basis for early detection of impaired diastolic function in CAD patients, and have certain clinical significance for predicting the severity of coronary lesions.

Ratcheting behavior of adult and juvenile cartilage under rolling load / 中国组织工程研究

BACKGROUND: Domestic and foreign scholars have done a lot of researches on the stress of articular cartilage under different mechanical environments and cyclic compressive loads, but they mainly studied the effect of cartilage under the cyclic compressive load. Studies on the effects of age factor on the mechanical properties of cartilage and studies regarding the properties of cartilage in complex stress environments are not exhaustive. OBJECTIVE: To investigate the effects of different rolling load conditions on the ratcheting behavior of adult and juvenile articular cartilage. METHODS: Adult cartilage and juvenile cartilage were used as experimental objects, and the load was applied by a rolling load device under different experimental conditions (compression: 10%, 20%, 30%; rolling rate: 1.66, 3.44, 6.68 mm/s; defect width: 1, 2,4 mm). At the same time, non-contact digital technology was used to collect the sample during the loading process, and the cyclical pressure was studied by analyzing and processing the image. The ratcheting behavior of adult and juvenile articular cartilage was studied under rolling load. RESULTS AND CONCLUSION: Under rolling load, the ratcheting strain of adult cartilage and juvenile cartilage showed a rapid increase followed by a slow increase tendency with the rolling load. With the increase of compression, the ratcheting strain of adult cartilage and juvenile cartilage increased. At the same amount of compression, the ratcheting strain of juvenile cartilage was greater than that of adult cartilage, and their ratcheting strain gradually decreased from the surface layer to the deep layer along the depth of cartilage. As the rolling rate increased, the ratcheting strain of adult cartilage and juvenile cartilage decreased. The ratcheting strain values and trends of 1 mm microdefect articular cartilage were similar to those of intact articular cartilage. Under the condition of 2,4 mm defect, the ratcheting strain value of the defected cartilage was higher than that of the intact cartilage.

Avaliação da deformação miocárdica pela ecocardiografia feature tracking em gatos com defeito perimembranoso do septo ventricular / Evaluation of myocardial deformation by the ecocardiography feature tracking in cats with perimembranosous defect of the septo ventricular

O desenvolvimento de novas ferramentas, como a ecocardiografia bidimensional feature tracking (2D-FTI), permite diagnosticar, de forma precoce, se há disfunção miocárdica em doenças cardíacas, inclusive as congênitas. O defeito septal ventricular (DSV) é a alteração congênita mais observada em felinos, no entanto pouco se sabe sobre a disfunção cardíaca nessa cardiopatia, especialmente em animais assintomáticos. O objetivo deste estudo foi avaliar, por meio do 2D-FTI, a deformação miocárdica ventricular esquerda pela mensuração dos índices ecocardiográficos strain (St) e strain rate (StR) radial, circunferencial e longitudinal, em gatos saudáveis e com DSV. Foram avaliados 12 gatos saudáveis e seis gatos com DSV para obtenção de St e StR em diversos segmentos miocárdicos. No sentido longitudinal, houve diferença estatística (P<0,05) para os segmentos septal basal, mediano e apical epicárdicos (P=0,0017; P<0,0001; P=0,0288), lateral mediano epicárdico (P=0,0327), septal mediano endocárdico (P=0,0035), lateral mediano endocárdico (P=0,0461), St epicárdico (P=0,0250) e St global (P=0,0382). Também houve diferença no segmento lateral mediano circunferencial endocárdico (P=0,0248), lateral mediano radial (St: P=0,0409; StR: P=0,0166) e posterior mediano radial (P=0,0369). O estudo evidenciou que, mesmo em animais assintomáticos com DSV, há redução na deformação miocárdica ventricular principalmente no sentido longitudinal, demonstrando maior vulnerabilidade dessas fibras.(AU)

The development of new tools, such as two-dimensional feature tracking (2D-FTI), allows early diagnosis of myocardial dysfunction in heart diseases including congenital heart disease. The ventricular septal defect (VSD) is the most frequently observed congenital abnormality in cats, however, little is known about cardiac dysfunction, especially in asymptomatic animals. The objective of this study was to evaluate the left ventricular myocardial deformation through 2D-FTI by the measurement of the radial, circumferential and longitudinal echocardiographic strain (St) and strain rate (StR) indices. Twelve healthy cats and six cats with VSD were evaluated to obtain St and StR in several myocardial segments. In the longitudinal direction, there was a statistical difference (P<0.05) for the epimyocardial basal septal, mid-septal, apical septal (P=0.0017; P<0.0001; P=0.0288), epimyocardial mid-lateral (P=0.0327), endomyocardial mid-septal (P=0.0035), endomyocardial mid-lateral (P=0.0461), St epimyocardial (P=0.0250) and St global (P=0.0382). There was also difference in the circumferential endomyocardial mid-lateral segment (P=0.0248), radial mid-lateral (St: P=0.0409; StR: P=0.0166) and radial mid-posterior (P=0.0369). The study showed that even in asymptomatic animals with VSD there is a reduction in ventricular myocardial deformation mainly in the longitudinal direction, demonstrating the fragility of these fibers.(AU)

Evaluation of left atrial function in asymptomatic dogs with chronic myxomatous mitral valve disease: two-dimensional feature-tracking echocardiography and Simpsons monoplanar methods / Avaliação da função atrial esquerda em cães assintomáticos com degeneração mixomatosa crônica de valva mitral: métodos ecocardiográficos bidimensional feature tracking e monoplanar de Simpson

The present study evaluated the volume and function of the left atrium by two-dimensional echocardiographic feature-tracking imaging (2D-FTI) and Simpson's monoplanar modeling in dogs with asymptomatic degenerative mitral valve disease (DMVD). The study consisted of 80 dogs that were divided into the following three groups: Group 1, 21 dogs (A); Group 2, 30 dogs (B1) and Group 3, 29 dogs (B2). The variable strain (contraction phase) was significantly lower in Group 3 than in Group 1 (12.92±4.54 x 16.69±5.74, p=0.014), and significant differences in the contraction strain index (CSI) were observed between all of the groups that were evaluated (1 = 46.82±8.10, 2 = 39.88±8.03, 3 = 35.25±5.64, p<0.0001). The atrial diastolic volume index (AdVi) that was measured by 2D-FTI was significantly higher in Group 3 than in Group 1 (1.31±0.95 x 0.96±0.31, p=0.038), and the atrial cardiac index (ACI) was also higher in Group 3 than in Group 1 (102.38±80.18 x 78.19±33.38, p=0.030). Atrial function was assessed by Simpson's monoplanar method, which demonstrated an increase in the left atrial systolic volume, while the contractile function decreased with an increasing disease severity (Group 1 0.21±0.06; Group 2 0.25±0.06; Group 3 0.32±0.08, p<0.0001). The intraobserver and interobserver assessments showed low to moderate variability; most of the values for the coefficient of variation for the variables that were analysed with each method were below 25%. Thus, DMVD was determined to cause an alteration in atrial function, especially in the contraction phase, and even in asymptomatic animals, and the methods of 2D-FTI echocardiography and Simpson's monoplanar evaluation are sensitive and early methods for the detection of left atrial dysfunction.(AU)

O presente estudo avaliou o volume e a função atrial esquerda obtidos por meio da ecocardiografia bidimensional feature tracking (2D-FTI) e pelo método monoplanar de Simpson em cães saudáveis e cães com DMVD assintomáticos. Foram avaliados 80 cães distribuídos em três grupos: Grupo 1, 21 cães (classe A); Grupo 2, 30 cães (classe B1) e Grupo 3, 29 cães (classe B2). A variável strain (fase de contração) foi significativamente menor no Grupo 3 que no Grupo 1 (12,92±4,54 x 16,69±5,74, p=0,014) e para a variável índice de strain de contração (CSI), houve diferença estatística entre todos os grupos avaliados (1 = 46,82±8,10; 2 = 39,88±8,03; 3 = 35,25±5,64, p<0,0001). O índice de volume diastólico atrial (iVdA) mensurado por meio do 2D-FTI foi significativamente maior no Grupo 3 que no Grupo 1 (1,31±0,95 x 0,96±0,31, p=0,038), assim como para o índice cardíaco atrial (iCA) também foi maior no Grupo 3 (102,38±80,18 x 78,19±33,38, p=0,030). A função atrial avaliada pelo método monoplanar de Simpson demonstrou um aumento do volume atrial esquerdo e do volume sistólico do átrio esquerdo, enquanto que a função contrátil diminuiu com o aumento da gravidade da doença (Grupo 1 0,21±0,06; Grupo 2 0,25±0,06; Grupo 3 0,32±0,08; p<0,0001). A avaliação intraobservador e interobservador, demonstrou variabilidade baixa a moderada, uma vez que a maioria dos valores de coeficiente de variação se concentraram abaixo de 25% para as variáveis analisadas em ambos os métodos. Dessa forma, conclui-se que a DMVD causa alteração na função atrial, principalmente na fase de contração, mesmo em animais assintomáticos e que a ecocardiografia 2D-FTI e o método monoplanar de Simpson são métodos sensíveis e precoces na detecção da disfunção atrial esquerda.(AU)

The value of TI-RADS,ultrasonic elastic strain rate and VTQ in identity of benign and malignant thyroid nodule / 安徽医科大学学报

Objective To explore the value of ultrsound tyorid imaige reporing and systerm (TI-RADS ), ultrasonic elastic strain rate (SR) and virtual touch tissue quantification (VTQ) three methods diagnosis of benign and malignant thyroid nodule. Methods 128 patients with thyroid nodule which need surgical treatment were selected as research objective. Before surgical treatment, all thyroid nodules detection with two-dimensional and color doppler ultrasoundand and classification by TI-RADS; All thyroid nodules measuring the SR of thyroid nodule as referenced of sternocleidomastoid; All thyroid nodules conducted with VTQ detection and recorded by shear wave velocity. Receiver operator characteristic curve (ROC) was used to evaluate TI-RADS, SR and VTQ in identifying benign and malignant thyroid nodule which by surgery pathology as the gold standard. Results TI-RADS, SR and VTQ had statistically significant (P < 0. 05 ) in benign and malignant thyroid nodules, the area under the ROC curve of TI-RADS, SR and VTQ were respectively 0. 83, 0. 87, 0. 92. Conclusion VTQ could improve the accuracy of ultrasonography in identifying benign and malignant thyroid nodule.

Testing of Mechanical Properties of Ballistic Gelatin / 医用生物力学

Objective To study the mechanical properties of ballistic gelatin and establish a dynamic constitutive model by a numerical method to lay the foundation for the related research on wound ballistics. Methods First, 20% ballistic gelatin samples at 10°C were prepared, and then, the quasi static and dynamic compressive mechanical properties of the ballistic gelatin were tested using a universal material testing machine and an aluminum Hopkinson bar, respectively. Results The quasi-static and dynamic compressive stress-strain curves of 20% ballistic gelatin at 10 ℃ were obtained. When the strain was 0.45, the true stress was 0.041, 0.083, 0.194, 14.515, 31.496, 55.597, and 96.678 MPa at a strain rate of 10-3, 10-2, 10-1, 5 800, 7 900, 10 400, and 13 000 s-1, respectively. When the strain rate was 13 000 s-1 and the strain increased from 0.4 to 0.5, the stress increased rapidly from 53.558 MPa to 164.417 MPa, equivalent to an increase by over 3.07 times. Conclusions The ballistic gelatin had a remarkable strain rate effect in the range of both low and high strain rates. The constitutive model with strain rate was established based on the experimental results with the form of σ=kε·mεn, and the material constants of 20% ballistic gelatin were obtained.

Effect of left ventricular hypertrophy and deformation on cardiac function in patients with uremia cardiomyopathy by using quantitative speckle tracking technology / 中南大学学报(医学版)

Objective:To evaluate the effect of left ventricular hypertrophy and deformation on cardiac function in patients with uremic cardiomyopathy (UCM) by using the technology of two dimensional speckle tracking imaging (2D-STI).Methods:A total of 67 UCM patients were randomly divided into the normal cardiac function group (subgroup A,32 cases) and the abnormal cardiac function group (subgroup B,35 cases)according to the New York Heart Association points (NYHA-P).A total of 30 healthy subjetcs served as the control group.Parameters including left ventricular ejection fraction (LVEF),left ventricular mass index (LVMI),left ventricular spherical index (LVSI),left ventricular myocardial mean radial strain (MRS),mean radial strain rate (MRSR),mean longitudinal strain (MLS),local systolic twist angle (STA),and mitral annulus maximum displacement (TMAD) were detected.Results:MLS,MRS,MRSR,LVSI,STA and TMAD in the Group A and Group B were lower than that in the control group (P＜0.05),and LVMI in the Group A and Group B was increased than those in the control group (P＜0.05);LVEE MLS,MRS,MRSR,LVSI and STAin the Group B was decreased than that in the Group A (P＜0.05).MLS in the Group A and B were positively correlated with LVEF and LVSI,but negatively correlated with LVMI.Using the point of 14.10％ for MLS to evaluate UCM patients with NYHA-P＞4 points,the sensitivity,the specificity and Yuedden index were 90.5％,71％ and 0.585,respectively.STA in UCM patients were lower than that in the control (P＜0.05).Conclusion:2D-STI possesses a unique advantage in detecting left ventricular strain and strain rate on left ventricular regional function in UCM with left ventricular hypertrophy and ventricular deformation.There is no direct correlation between the left ventricular hypertrophy and ventricular deformation,but the ventricular hypertrophy and deformation are correlated with regional cardiac function and clinical cardiac function.Left ventricular regional dysfunction may occur before cardiac hypertrophy and deformation.

Assessment of left ventricular diastolic function in patients with uremia by diastolic strain rate parameters / 中华超声影像学杂志

Objective To evaluate the left ventricular diastolic function in patients with uremia by two-dimensional speckle tracking technology ( 2D-STI ) . Methods Ninety-three patients with uremia ( serum creatinine value≥ 700 μmol/l) and 29 controls were included . Uremia patients were divided into group with decreased LVEF ( LVEF < 50％ ,group C ,19 cases) and group with normal LVEF ( LVEF≥50％ ) . The latter were divided into group with normal diastolic function ( group A ,31 cases) and group with diastolic dysfunction ( group B ,23 cases) according to the diastolic function;pulsed wave tissue Dopper imaging datas included:diastolic velocity e1′,a1′ and e2′,a2′ at septal or lateral sites of mitral annulus , average E/e′and e′/a′. 2D-STI strain and strain rate parameters included:the longitudinal peak systolic strain ( GLS) ,the longitudinal peak systolic strain rate ( LSRs) ,longitudinal peak strain rate in early diastole (LSRe)andE/LSRe.Results ①Systolicfunctionparameters:comparedwithcontrolgroup,LVEF decreased significantly only in group C( P <0 .05) ,while there was no significant difference among group A ,B and control group ( P> 0 .05 ) ;GLS in group A ,B and C decreased significantly and showed a decreasing trend among these three groups( P <0 .05) ;LSRs in group B and C decreased significantly ,while there was no significant difference between group A and control group( P > 0 .05) . ② Diastolic function parameters:compared with control group ,the average E/e′decreased significantly in group B and C( P <0 .05) ,while group A showed no significant difference( P > 0 .05) . Compared with group A ,the average E/e′increased significantly in group B and C ( P < 0 .05) . Compared with control group ,LSRe in three uremia groups decreased significantly ,which showed a decreasing trend among these three groups ( P <0 .05) ;however ,E/LSRe in three uremia groups increased significantly and showed an increasing trend among these three groups ( P < 0 .05 ) . ③ The correlation analysis showed that there were positive correlations between average e′ and LSRe and between average E/e′ and E/LSRe in uremic patients . Conclusions In patients with uremia ,left ventricular systolic and diastolic function impaired in the early phase . Strain rate parameters in diastole especially E/LSRe obtained by 2D-STI can be used as sensitive , early parameter for evaluation of left ventricular diastolic dysfunction .

A preliminary study of left ventricular function assessement in patients with atrial fibrillation by MR feature tracking technique / 中华放射学杂志

Objective To explore the clinical application value of left atrial function with feature tracking cardiac magnetic resonance imaging (FT-CMR) by evaluating preliminarily left atrial strain and strain rate in patients with atrial fibrillation. Methods Thirty patients with paroxysmal atrial fibrillation, thirty patients with persistent atrial fibrillation and twenty-two healthy subjects were enrolled. All the subjects underwent cardiac magnetic resonance imaging with the real steady-state free precession(SSFP) sequence. FT-CMR parameters included left atrial strain and strain rate parameters, left atrial volume and function parameters were detected by using offline cardiovascular analysis software, respectively. Left atrial strain and strain rate parameters included left atrial total strain(Εs), passive strain(Εe), active strain(Εa), peak positive strain rate(SRs), peak early negative strain rate(SRe)and peak late negative strain rate(SRa). Volume and function parameters included maximum of left atrial volume(LAVmax), minimum of left atrial volume(LAVmin), total left atrial emptying fraction(LATEF), passive left atrial emptying fraction(LAPEF)and active left atrial emptying fraction(LAAEF). The differences in the general data among the paroxysmal atrial fibrillation group, the persistent atrial fibrillation group and the control group were compared by usingχ2 test or ANOVA analysis. The differences in all parameters between the atrial fibrillation group and the control group, the paroxysmal atrial fibrillation group and the persistent atrial fibrillation group were compared by using independent t test. Left atrial strain and strain rate parameters on an intra-observer and inter-observer were determined by intraclass correlation coefficient(ICC)analyses. Results Compared to control group, LAVmax and LAVmin in atrial fibrillation group were significantly increased(t=9.737,7.889,P<0.001);The LATEF and LAPEF had no significant difference, the LAAEF in two groups had statistically significant difference(t=-4.762,P<0.001).The absolute value of Es, Ee, Ea, SRs, SRe, SRa in atrial fibrillation group were significantly reduced than in control group(t=-7.732,-6.610,-6.493,-7.546, 6.864, 5.917,P<0.001). Compared with paroxysmal atrial fibrillation group, LAVmax and LAVmin in persistent atrial fibrillation group were increased obviously, LATEF and LAPEF were significantly decreased, and the differences were statistically significant(t=-4.575,-5.524, 4.002, 4.028,P<0.001).The LAAEF in two groups had no statistically significant difference. Compared with strain and strain rate in two groups, absolute value of Es, Ee, Ea, SRs, SRe, SRa in persistent atrial fibrillation group significantly decreased than in paroxysmal atrial fibrillation(t=4.310, 3.128, 4.465, 5.496,-3.290,-3.863,P<0.001). The intra-group and inter-group had well correlation coefficients between the observers in the left atrial strain and strain rate parameters of the subjects(ICC=0.85—0.94,0.81—0.90). Conclusions FT-CMR technique can be used to assess the left atrial strain and strain rate in patients with atrial fibrillation;Left atrial reservoir, conduit and booster-pump functions in patients with atrial fibrillation were impaired. Patients with persistent atrial fibrillation had worse left atrial function throughout the entire cardiac cycle compared with those with paroxysmal atrial fibrillation.

Normal reference values for left ventricular peak systolic longitudinal strain and strain rate in healthy children at different ages: a preliminary analysis / 第三军医大学学报

Objective To analyze the normal reference values of left ventricular longitudinal peak systolic strain (LS) and strain rate (LSr) by two-dimensional speckle tracking imaging (2D-STI) in healthy children at different ages.Methods Clinical ultrasound data of 330 healthy children who taking physical examination in our hospital from September 2015 to November 2016 were collected and retrospectively.They were divided into 7 groups according to their ages,that is,neonate group (0 to 28 days old),infant group (28 days to 1 year old),toddle group (1 to 3 years old),pre-school group (3 to 6 years old),school age group (6 to 9 years old),pre-adolescence group (9 to 13 years old) and adolescence group (13 to 18 years old).2D-STI was performed in the 3 apical projections of left ventricle (LV).The regional peak systolic longitudinal strain and strain rate of LV were measured.Results ① Significant differences were found in the LS and LSr values from 6 segments of the same wall (P ＜ 0.05),and the LS and LSr values were gradually increased from basal segment to apical segment.②There were no significant differences in the LS,LSr and global LS (GLS) values of 18 segments between sexes (P ＞ 0.05).③ Except the basal segments of posterior wall,inferior wall and posterior septum,LS value was gradually elevated with the increase of age (LS ＜LSinfant ＜ LStoddler,pre-shool and school age ＜ LSpre-adolescence and adolescence),So was GLS value.④LS in 18 segments had a positive correlation with age,and the value of apical segment in lateral wall was most remarkably correlated (r =0.551,P ＜0.01);Regional LS had a negative correlation with heart rate,and that of middle segment in lateral wall was the most apparent (r =-0.625,P ＜ 0.01);GLS was positively influenced by age (r =0.665,P ＜ 0.01) and negatively affected by heart rate (r =-0.625,P ＜ 0.01).⑤The heterogeneities were found in the correlations of regional LSr with age and heart rate in segments and in the LSr among different age groups.Conclusion Normal reference values of LV peak LS and LSr are established for healthy children at different ages,and they possess their own characteristics.

Roles of MyD88 and TRIF in cardiac dysfunction during sepsis / 中华危重病急救医学

Objective To investigate the roles of myeloid differentiation factor 88 (MyD88) and TIR domain-containing adaptor inducing interferon-β (TRIF) in sepsis-induced myocardial dysfunction, and to analyze whether strain rate (SR) can be early sensitive evaluation for septic heart failure.Methods Sixty-four healthy male C57BL/6 mice were divided into four groups by random number table (n = 16 in each group): sham group, cecum ligation and puncture (CLP)-induced sepsis model group, anti-MyD88 group and anti-TRIF group. The anti-MyD88 group and anti-TRIF group were injected with 5μL/g of anti-MyD88 antibody or anti-TRIF antibody through the tail veins 2 hours before CLP. Eight animals in each group were used to observe the survival of 24 hours, and the other 8 myocardial tissues were harvested for examination. The cardiac function was evaluated by echocardiography before and 6 hours and 12 hours after operation. The mRNA expressions of MyD88, TRIF and inflammatory factors in myocardium were measured by polymerase chain reaction (PCR) at 24 hours after operation, and the degree of neutrophils infiltration was detected by myeloperoxidase (MPO) activity.Results The number of 24-hour survive in anti-MyD88 group and anti-TRIF group were higher than that in CLP group (number: 4, 3 vs. 2,P = 0.044,P = 0.047). Compared with sham group, the cardiac function was significantly decreased, the mRNA expressions of myocardial tissues MyD88, TRIF, interleukin (IL-1, IL-6) and tumor necrosis factor-α (TNF-α) were significantly increased, and the infiltration of neutrophils were obvious in CLP group. Compared with CLP group, the left ventricular short axis fractional shortening rate (FS) and SR were significantly increased after 12 hours in anti-MyD88 group and anti-TRIF group [FS: (49.52±1.78)%, (49.89±1.49)%vs. (41.11±1.63)%, SR (s-1): 17.63±2.16, 17.85±1.64 vs. 12.55±1.84]; the mRNA expressions of MyD88, TRIF and inflammatory factors were significantly decreased [MyD88 mRNA (A value): 0.463±0.046, 0.505±0.048 vs. 0.638±0.102, TRIF mRNA (A value): 0.413±0.031, 0.410±0.021 vs. 0.625±0.057, IL-1 mRNA (A value):0.569±0.101, 0.570±0.091 vs. 0.946±0.171, IL-6 mRNA (A value): 0.551±0.143, 0.431±0.157 vs. 0.850±0.194, TNF-α mRNA (A value): 0.471±0.082, 0.444±0.093 vs. 0.707±0.094]; and the infiltration of neutrophils were significantly decreased [MPO (U/L): 62.34±2.60, 60.87±2.40 vs. 73.83±4.90], with statistically significant differences (allP 0.05).Conclusions Blocking MyD88 and TRIF expression play significant and similar roles in protecting cardiac deterioration from sepsis by attenuating cytokine release, reducing neutrophil infiltration. SR can sensitively assess septic cardiac dysfunction.

Avaliação da depressão miocárdica por meio do feature tracking bidimensional em cadelas com sepse / Assessment of myocardial depression by two-dimensional feature tracking in dogs with sepsis

O objetivo deste estudo prospectivo foi analisar a função do ventrículo esquerdo de cadelas que apresentavam sepse ou não e diagnosticar a depressão miocárdica de forma precoce, por meio do feature tracking imaging bidimensional (FTI-2D).Vinte e nove cadelas diagnosticadas com piometra, patologia usada como modelo experimental para sepse, foram avaliadas. Os animais foram submetidos ao exame ecocardiográfico convencional e ao FTI-2D e divididos em três grupos: grupo I (controle), grupo II (piometra sepse) e grupo III (piometra não sepse). Em relação aos parâmetros da ecocardiografia convencional, não houve diferença estatística entre os grupos avaliados. Quanto ao strain radial, os grupos II e III apresentaram função ventricular inferior no momento do diagnóstico (22,805,80 grupo I; 18,455,96 grupo II; 18,719,45 grupo III; P=0,032) e o grupo III manteve essa redução no retorno. Já no strain rate radial, apenas o grupo III obteve função ventricular inferior no momento do diagnóstico (1,900,57 grupo I; 1,910,70 grupo II, 1,570,53 grupo III; P=0,021). Para o strain longitudinal, observou-se função ventricular mais baixa nos grupos II e III no momento do diagnóstico (11,043,38 grupo I; 8,593,97 grupo II; 8,211,99; P=0,048) e após 10 dias de pós-cirúrgico (11,043,38 grupo I; 9,002,16 grupo II; 8,122,27 grupo III; p=0,048). O FTI-2D foi capaz de detectar alterações precoces da função ventricular esquerda, que não foram observadas no exame ecocardiográfico convencional, sugerindo quadro de depressão miocárdica, até mesmo em cadelas com piometra sem quadro clínico evidente de sepse. Assim, essa modalidade pode ser útil no diagnóstico, pois pode detectar alterações cardíacas precoces, possibilitando uma intervenção terapêutica rápida.(AU)

The aim of this prospective study was to analyze the left ventricular function of dogs who had sepsis or not and diagnose myocardial depression early on through the two-dimensional feature tracking imaging (2D-FTI). Twenty-nine dogs diagnosed with pyometra, a pathology used as an experimental model for sepsis were evaluated. The animals were subjected to conventional echocardiography and 2D-FTI, and divided into three groups: Group I (control), group II (sepsis pyometra) and group III (no sepsis pyometra). Regarding the parameters of conventional echocardiography, there was no statistical difference between the groups. As for the radial Strain, group II and III had lower ventricular function at diagnosis (22.805.80 Group I; 18.455.96 Group II; 18.719.45 Group III; P = 0.032) and group III maintained this reduction in return. Regarding the radial Strain rate, only the III group had lower ventricular function at diagnosis (1.900.57 Group I; 1.910.70 Group II, 1.570.53 Group III; P = 0.021). For the Longitudinal Strain we observed lower ventricular function in groups II and III at diagnosis (11.043.38 Group I, Group II 8.593.97, 8.211.99; P = 0.048) and ten days after surgery (11.043.38 Group I; 9.002.16 Group II; 8.122.27 Group III; P = 0.048). The 2D-FTI was able to detect early changes in left ventricular function, suggesting myocardial depression frame, even in female dogs with pyometra without clear clinical picture of sepsis, which were not seen in conventional echocardiography. Thus, this model can be useful in diagnosis, because it can detect early cardiac changes, enabling a rapid therapeutic intervention.(AU)

Cambios estructurales y funcionales del ventrículo derecho en deportistas de alto rendimiento evaluados por ecocardiografía con strain por speckle tracking / Structural and functional changes of right ventricle in highly trained athletes evaluated by echocardiography by speckle tracking strain / Alterações estruturais e funcionais do ventrículo direito em atletas altamente treinados avaliados por ecocardiografia com strain por speckle tracking

Introducción. El entrenamiento físico intenso se asocia a cambios cardíacos estructurales tanto del ventrículo izquierdo como del ventrículo derecho (VD). Sin embargo, no hay estudios en atletas argentinos que valoren con técnicas ecocardiográficas actuales dichos cambios, con el fin de reconocer precozmente aquellos que presentan dilataciones o hipertrofias patológicas que puedan asociarse a aumento del riesgo de muerte súbita. Objetivo. Evaluar la anatomía, función y comportamiento del VD en deportistas que realizan actividades isométricas o estáticas (GE), isotónicas o dinámicas (GD) y compararlo con pacientes controles no deportistas (GC). Materiales y métodos. Se realizó un ecocardiograma transtorácico, evaluando principalmente el VD a través del TAPSE, los diámetros diastólicos y sistólicos, el Doppler tisular (DTI), y el strain y strain rate por speckle tracking. Resultados. Incluimos 117 pacientes, 11 en GE, 56 en GD, y 50 controles. En los deportistas el acortamiento longitudinal con strain rate a nivel apical y basal, el diámetro diastólico apical y basal, el diámetro sistólico basal, las ondas S, E y A a nivel basal de la pared libre del VD por DTI, y las ondas S y E a nivel medio de la pared libre del VD por DTI mostraron diferencias significativas, con valores mayores en el grupo de deportistas tanto estáticos como dinámicos. Conclusión. Nuestro estudio demostró que los diámetros mayores del VD en los deportistas sanos se asocian a aumento de la deformación miocárdica medida por DTI y a través del acortamiento longitudinal del strain.

Introduction. The intense physical training is associated with cardiac structural changes in both the left ventricle and the right ventricle (RV). However, no studies in Argentine athletes who value with current echocardiographic techniques such changes, in order to recognize early those with dilations or pathological hypertrophy that may be associated with increased risk of sudden death. Objective. Evaluate the anatomy, function and behavior of RV in athletes who perform isometric or static (SG), isotonic or dynamic activities (DG) and compared with control patients non-athletes (CG). Materials and methods. Each patient underwent transthoracic echocardiography, evaluating primarily the RV through TAPSE, the diastolic and systolic diameters, Doppler tissue imaging (DTI), and the strain and strain rate by speckle tracking. Results. We included 117 patients, 11 in SG, 56 in DG, and 50 controls. In athletes the longitudinal shortening with strain rate at apical and basal level, the diastolic diameter apical and basal systolic diameter baseline, the S, E and A waves at baseline of the RV free wall by DTI, and waves S and E at the middle level of the RV free wall by DTI showed significant differences, with higher values in the group of both static and dynamic athletes. Conclusion. Our study showed that the largest diameters of RV in healthy athletes are associated with increased myocardial deformation measured by DTI and through the longitudinal shortening strain.

Introdução. O treinamento físico intenso está associado a alterações estruturais cardíacas, tanto no ventrículo esquerdo e do ventrículo direito (VD). No entanto, não existem estudos em atletas argentinos que valorizam com técnicas de ecocardiografia atuais tais mudanças, a fim de reconhecer cedo aqueles com dilatações ou hipertrofia patológica que pode estar associado ao aumento do risco de morte súbita. Objetivo. Avaliar a anatomia, função e comportamento do VD em atletas que realizam atividades isométricas ou estáticas (GE), isotônicas ou dinâmicas (GD) e em comparação com pacientes de controle não-atletas (GC). Materiais e métodos. Cada paciente foi submetido a uma ecocardiografia transtorácica, avaliando principalmente o RV através do TAPSE, os diâmetros diastólicos e sistólicos, o Doppler tecidual (DTI), e o strain e strain rate por speckle tracking. Resultados. Foram incluídos 117 pacientes, 11 no GE, 56 no GD, e 50 controles. Em os atletas o encurtamento longitudinal com strain rate a nível apical e basal, o diâmetro diastólico apical e basal, o diâmetro sistólico basal, as ondas S, E e A na níveis basal da parede livre do VD pelo DTI, e ondas S e E no nível médio da parede livre do VD por DTI apresentou diferenças significativas, com valores mais elevados no grupo de ambos os atletas estáticas e dinâmicas. Conclusão. Nosso estudo mostrou que os maiores diâmetros de VD em atletas saudáveis são associados com aumento da deformação miocárdica medida pelo DTI e através do encurtamento longitudinal do strain.

Deformação miocárdica radial por meio do speckle tracking bidimensional em suínos com hipertensão pulmonar induzida e tratados com angiotensina-(1-7) / Evaluation of myocardial radial deformation by bidimensional speckle tracking in pigs with pulmonary hypertension treated with angiotensin- (1-7)

A hipertensão arterial pulmonar (HAP) é uma doença complexa, caracterizada por disfunção endotelial, que resulta em remodelamento vascular pulmonar e elevação da pressão arterial pulmonar, com consequente insuficiência cardíaca direita. O speckle tracking bidimensional (2D-STE) é uma das mais recentes ferramentas da ecocardiografia, o qual tem sido empregado para avaliação mais precoce da função ventricular e do efeito da HAP sobre a função dos ventrículos esquerdo e direito. O objetivo deste estudo foi avaliar a deformação (St e StR) miocárdica radial do VE em modelo experimental de suínos com HAP induzida e tratados com angiotensina-(1-7), a fim de verificar as possibilidades desse novo fármaco nas respostas clínica e hemodinâmica, pois apresenta efeitos anti-inflamatório e vasodilatador, bem como ações antiproliferativas no sistema cardiovascular. Neste estudo, foi possível observar que os animais tratados com Ang-(1-7) apresentaram St e StR radiais maiores que o grupo placebo aos 60 dias de experimento, demonstrando uma melhora na função sistólica do miocárdio pelo aumento da deformação miocárdica (16,06±7,50 - placebo; 25,14±14,91 - Ang-(1-7)) e StR (1,28±0,51 - placebo; 1,51±0,58 - Ang-(1-7)). Essa melhora na função sistólica pode ser atribuída aos efeitos do fármaco, que reduziram também o desenvolvimento da hipertensão pulmonar. Diante dos resultados, acredita-se que a Ang-(1-7) possa ser um medicamento promissor para tratamento da HAP.(AU)

Pulmonary arterial hypertension (PAH) is a complex disease characterized by endothelial dysfunction resulting in pulmonary vascular remodeling, increased pulmonary arterial pressure, with subsequent right heart failure. The two-dimensional speckle tracking (2D-STE) is one of the newer tools used for early assessment of ventricular function. The aim of this study was to evaluate the radial myocardial deformation (St and StR) of LV in experimental pigs with induced PAH and treated with Ang- (1-7), checking the possibilities of this new drug in clinical and hemodynamic response, since it has anti-inflammatory effects and antiproliferative actions on the cardiovascular system. In this study we observed that animals treated with Ang (1-7) had radial St and StR higher than the placebo group at 60 days of the experiment demonstrating an improvement in systolic function of the myocardium by increased myocardial deformation (16.06±7.50 - placebo; 25.14±14.91 - Ang (1-7)) and StR (1.28±0.51 - placebo; 1.51±0.58 - Ang (1-7)). This improvement in systolic function can be attributed to drug effects while also reducing the development of pulmonary hypertension. Based on the results it is believed that Ang (1-7) may be a promising drug for the treatment of PAH.(AU)