Left Ventricular Short-axis Views Research Articles

Transthoracic cardiac ultrasonic shear wave elastography for detecting myocardial stiffness in healthy and hypertrophic cardiomyopathy individuals

Objective: To explore the feasibility of transthoracic cardiac shear wave elastography (SWE) for non-invasive quantitative measurement of myocardial stiffness in healthy volunteers (HV) and hypertrophic cardiomyopathy (HCM) patients, and analyze the relationship between myocardial shear wave velocity (SWV) and left ventricular diastolic function. Methods: A total of 16 HV who underwent health check-ups and 5 HCM patients who visited the Cardiology Outpatient Clinic at Fujian Medical University Affiliated Union Hospital from September 2022 to October 2023 were prospectively recruited. The SWE technique was used to measure SWV of the basal segment of the interventricular septum, including left ventricular long-axis myocardial shear wave velocity (LA-SWV) and short-axis myocardial shear wave velocity (SA-SWV). The intraclass correlation coefficient (ICC) was employed to evaluate the intra-observer and inter-observer consistency of SWV measurements. Spearman's correlation analysis was performed to evaluate the correlation between baseline characteristics, echocardiography parameters and SWV. Quantitative data were expressed as median (interquartile range) [M (Q1, Q3)]. Results: The HV group had the age of 34.5 (24.0, 51.0) years, including 8 males (50%); the HCM group had the age of 34.0 (27.0, 46.0) years, including 3 males (60%). The intra-observer and inter-observer ICC (95%CI) for LA-SWV measurements were 0.806 (0.592-0.907) and 0.785 (0.471-0.949), respectively, indicating high consistency; the intra-observer and inter-observer ICC (95%CI) for SA-SWV measurements were 0.746 (0.359-0.862) and 0.602 (0.245-0.834), indicating moderate consistency. LA-SWV [1.74 (1.65, 1.77) vs 1.25 (1.22, 1.33) m/s, P<0.001] and SA-SWV [1.98 (1.96, 2.15) vs 1.52(1.46, 1.55) m/s, P<0.001] were significantly higher in HCM group than those in HV group. There was no significant correlation between SWV and gender, age or body mass index (all P>0.05). In the left ventricular long-axis view, interventricular septal end-diastolic thickness (IVSDT) (r=0.749, P<0.001), early diastolic mitral valve flow velocity/early diastolic mitral annular peak motion velocity (E/e') (r=0.669, P<0.001), and left ventricular mass index (LVMI) (r=0.679, P<0.001) were positively correlated with LA-SWV, while e' (r=-0.545, P<0.001) and late diastolic mitral annular peak motion velocity (r=-0.489, P=0.021) were negatively correlated with LA-SWV. In the left ventricular short-axis view, IVSDT (r=0.784, P<0.001), E/e' (r=0.657, P<0.001), and LVMI (r=0.660, P<0.001) were positively correlated with SA-SWV, while e' was negatively correlated with SA-SWV (r=-0.658, P<0.001). Conclusions: The use of SWE technique to measure myocardial SWV can be applied to assess the stiffness differences between normal myocardium and HCM myocardium. Additionally, SWV is correlated with left ventricular diastolic function indices and can effectively evaluate the diastolic dysfunction of the left ventricle caused by HCM.

TTE left ventricular short-axis view showed that the mitral valve vegetation disappeared after treatment.

TTE left ventricular short-axis view showed that the mitral valve vegetation disappeared after treatment.

Deep learning for transesophageal echocardiography view classification

Transesophageal echocardiography (TEE) imaging is a vital tool used in the evaluation of complex cardiac pathology and the management of cardiac surgery patients. A key limitation to the application of deep learning strategies to intraoperative and intraprocedural TEE data is the complexity and unstructured nature of these images. In the present study, we developed a deep learning-based, multi-category TEE view classification model that can be used to add structure to intraoperative and intraprocedural TEE imaging data. More specifically, we trained a convolutional neural network (CNN) to predict standardized TEE views using labeled intraoperative and intraprocedural TEE videos from Cedars-Sinai Medical Center (CSMC). We externally validated our model on intraoperative TEE videos from Stanford University Medical Center (SUMC). Accuracy of our model was high across all labeled views. The highest performance was achieved for the Trans-Gastric Left Ventricular Short Axis View (area under the receiver operating curve [AUC] = 0.971 at CSMC, 0.957 at SUMC), the Mid-Esophageal Long Axis View (AUC = 0.954 at CSMC, 0.905 at SUMC), the Mid-Esophageal Aortic Valve Short Axis View (AUC = 0.946 at CSMC, 0.898 at SUMC), and the Mid-Esophageal 4-Chamber View (AUC = 0.939 at CSMC, 0.902 at SUMC). Ultimately, we demonstrate that our deep learning model can accurately classify standardized TEE views, which will facilitate further downstream deep learning analyses for intraoperative and intraprocedural TEE imaging.

Balanced Steady-State Free Precession Cine MR Imaging in the Presence of Cardiac Devices: Value of Interleaved Radial Linear Combination Acquisition With Partial Dephasing.

Balanced steady-state free precession (bSSFP) is important in cardiac MRI but suffers from off-resonance artifacts. The interpretation-limiting artifacts in patients with cardiac implants remain an unsolved issue. To develop an interleaved radial linear combination bSSFP (lcSSFP) method with partial dephasing (PD) for improved cardiac cine imaging when implanted cardiovascular devices are present. Prospective. Flow phantom adjacent to a pacemaker and 10 healthy volunteers (mean age ± standard deviation: 31.9 ± 2.9 years, 4 females) with a cardioverter-defibrillator (ICD) positioned extracorporeally at the left chest in the prepectoral region. A 3-T, 1) Cartesian bSSFP, 2) Cartesian gradient echo (GRE), 3) Cartesian lcSSFP, and 4) radial lcSSFP cine sequences. Flow artifacts mitigation using PD was validated with phantom experiments. Undersampled radial lcSSFP with interleaving across phase-cyclings and cardiac phases (RLC-SSFP), combined with PD, was then employed for achieving improved quality of cine images from left ventricular short-axis view. The image quality in the presence of cardiac devices was qualitatively assessed by three independent raters (1=worst, 5=best), regarding five criteria (banding artifacts, streak artifacts, flow artifacts, cavity visibility, and overall image quality). Wilcoxon rank-sum test for the five criteria between Cartesian bSSFP cine and RLC-SSFP with PD. Fleiss kappa test for inter-reader agreement. A P value < 0.05 was considered statistically significant. Based on simulations and phantom experiments, 60 projections per phase cycling and 1/6 PD were chosen. The in vivo experiments demonstrated significantly reduced banding artifacts (4.8 ± 0.4 vs. 2.7 ± 0.7), fewer streak artifacts (3.7 ± 0.6 vs. 2.6 ± 0.7) and flow artifacts (4.4 ± 0.4 vs. 3.7 ± 0.6), therefore improved cavity visibility (4.1 ± 0.4 vs. 2.9 ± 0.9) and overall quality (4.0 ± 0.4 vs. 2.7 ± 0.7). RLC-SSFP method with PD may improve cine image quality in subjects with cardiac devices. 2. Stage 1.

Abstract 15815: Left Atrial Strain Characterizes the Atrio-ventricular Substrate Responsive to Cardiac Resynchronization Therapy in Patients With Intermediate Electrocardiographic Criteria

Introduction: Guidelines favor patient selection by left bundle branch block (LBBB) with QRS width ≥150 ms for cardiac resynchronization therapy (CRT). Predicting CRT response in patients with QRS width 120 to 149 ms or non-LBBB remains difficult. Left ventricular (LV) global longitudinal strain (GLS) and systolic stretch index (SSI) have shown to characterize the ventricular substrate responsive to CRT. However, the potential application of longitudinal left atrial (LA) strain remains unclear. Hypothesis: Baseline LA strain has prognostic value in CRT patients with intermediate ECG criteria. Methods: We studied 195 patients who underwent CRT based on routine indications: ejection fraction ≤35% and QRS width ≥120 ms. GLS was assessed using the 3 standard apical views. Radial SSI was derived from the mid LV short axis view. Peak longitudinal LA strain was derived from the 2 and 4-chamber apical view. The predefined combined clinical endpoint was death, heart transplant or left ventricular assist device over 4 years after CRT. Results: LA strain was feasible in 162 (83%) of the CRT candidates: QRS duration 156 ± 26 ms, 39.5% had LBBB with QRS ≥ 150ms, 60.5% had intermediate ECG criteria. High peak longitudinal strain (&gt;median, 10.1%) was associated with favorable event-free survival (p&lt;0.001). Patients with intermediate ECG criteria for CRT and both high peak longitudinal LA strain and high GLS (&gt;median, 8.4%) had similar outcome to those with Class I indications for CRT. Multivariable analysis revealed that LA strain had independent prognostic value (hazard ratio 0.9 per LA strain %, p &lt; 0.001) even after adjusted for other clinical, electrophysiological and echocardiographic covariates including QRS morphology and duration, GLS and SSI. Conclusions: Peak LA strain had important prognostic value in candidates for CRT. Prognostic value of LA strain was additive to LV strain characteristics and most significant in CRT patients with intermediate ECG criteria for CRT.

Radial Motion Estimation of Myocardium in Rats with Myocardial Infarction: A Hybrid Method of FNCCGLAM and Polar Transformation

Ultrasound elastography is a novel approach of evaluating regional myocardial systolic function and detecting infarcted area. This study aims to evaluate the radial motion of myocardial infarction (MI) area in left ventricular parasternal short axis (PSAX) view using a hybrid method of fast normalized cross-correlation and global analytic minimization (FNCCGLAM) and polar transformation. Fifteen rats were randomly selected for sham group, MI group and ischemia-reperfusion (IR) group (N = 5 for each group). The ultrasound radiofrequency data of the PSAX view of rat heart were acquired. After polar transformation of the data, the infarcted myocardium with the change of mechanical property was tracked over one myocardial systolic phase by the proposed method in comparison with fast normalized cross-correlation (FNCC) and dynamic programming analytic minimization (DPAM). To obtain a clear visualization of the myocardium, the inverse polar transformation was performed. The results indicated that the use of FNCCGLAM refined the myocardial displacements to obtain high-quality myocardial elastographic map with a higher contrast-to-noise ratio and dynamically tracked the infarcted myocardial segment with a higher success rate in comparison with FNCC and DPAM. It was found that the radial systolic motion of the infarcted anterior segment in the MI group reduced significantly (p < 0.05) in comparison with the sham group, while the systolic function of that myocardial segment in the IR group recovered at some extent. The results in this study suggest that FNCCGLAM is superior to FNCC and DPAM with the improved accuracy and robustness of motion estimation and has potentials as displacement estimator in ultrasound elastography.

Usefulness of pericardial lung ultrasonography for the diagnosis of cardiogenic pulmonary edema in dogs

To investigate whether lung ultrasonography (LUS) performed around the heart, where the lungs are in contact with the pericardium (ie, pericardial LUS), could be used for the diagnosis of cardiogenic pulmonary edema (CPE) in dogs with degenerative mitral valve disease (DMVD). 15 control dogs with healthy hearts and 26 dogs with DMVD. In a prospective multicenter study design, dogs with DMVD were assigned to 2 groups: those with CPE (n = 11) and those without CPE (15). Thoracic radiography, echocardiography, and pericardial LUS were performed for all dogs. For pericardial LUS, the left ventricular short-axis view was obtained with a sector probe (dog positioned in right parasternal recumbency) and the number of B lines was recorded. Accuracy of pericardial LUS for the diagnosis of CPE was calculated, with thoracic radiography used as the reference standard. On thoracic radiography, all dogs with CPE had a diffuse distribution of interstitial to alveolar pulmonary infiltrates. On pericardial LUS, most control dogs (14/15) and dogs with DMVD but no CPE (13/15) had ≤ 2 B lines, whereas all dogs with DMVD and CPE had ≥ 3 B lines. The presence of ≥ 4 B lines had high sensitivity (91%; 95% confidence interval, 62% to 98%) and excellent specificity (100%; 95% confidence interval, 89% to 100%) for the diagnosis of CPE, and the area under the receiver operating characteristic curve was 0.99. Results suggested that identification of ≥ 4 B lines extending from the epicardium of the left ventricle into the lung field on pericardial LUS may be useful in the diagnosis of CPE in dogs with DMVD. Additional research is needed to determine whether pericardial LUS allows differentiation between CPE and pneumonia.

Effects of modified acidic fibroblast growth factor mediated by nanoliposomes combined with ultrasound-targeted microbubble destruction on left ventricular systolic function in diabetic rats

Objective To investigate the effects of modified acidic fibroblast growth factor (MaFGF) mediated by nanoliposomes combined with ultrasound-targeted microbubble destruction (UTMD) on left ventricular systolic function in early diabetes mellitus(DM) rats. Methods The nanoliposomes containing MaFGF(MaFGF-nlip) were prepared by reverse phase evaporation method. Among 60 male Sprague Dawley (SD) rats, 50 rats were randomly selected and were induced to be DM models by streptozotocin(STZ) through intraperitoneal injecting, the other 10 rats as control group. Then DM rats were randomly divided into 4 groups: DM model group, MaFGF solution group, MaFGF-nlip group and MaFGF-nlip+ UTMD group. After the successful induction of DM model, the intervention was performed twice a week.After 12 weeks of intervention, all rats underwent conventional echocardiography and velocity vector imaging (VVI). Left ventricular ejection fraction (LVEF) and left ventricular fraction shortening(LVFS) were measured by conventional echocardiography. The mean peak systolic radial velocity (Vs), radial strain (Sr) and radial strain rate (SRr) of six walls at the papillary muscle level were measured in left ventricular short-axis view by VVI. At last, myocardial tissue of all rats were stained with Sirius red to evaluate myocardial interstitial fibrosis. The level of myocardial apoptosis was evaluated by TUNEL staining, and the changes of myocardial ultrastructure were observed by transmission electron microscopy. Results The prepared MaFGF-nlip were more rounded, evenly dispersed, and of good stability and high encapsulation efficiency. Twelve weeks later after intervention, LVEF, LVFS, Vs, Sr and SRr in the DM model group were significantly lower than those in the control group (all P<0.05). LVEF, LVFS, Vs, Sr and SRr in the MaFGF-nlip+ UTMD group were significantly higher than those of the DM model group and other intervention groups (all P<0.05). The results of Sirius red staining and Tunel staining showed that CVF and AI in the DM model group were significantly higher than those in the control group (all P<0.05). For MaFGF-nlip+ UTMD group, CVF and AI were significantly decreased compared with the DM model group and other intervention groups(all P<0.05). According to the results of transmission electron microscopy, compared with the DM model group, the improvement of myocardial ultrastructure was the most obvious in the MaFGF-nlip+ UTMD group. Conclusions MaFGF delivered by using nanoliposomes combined with UTMD can improve the left ventricular systolic function in diabetic rats by inhibiting the myocardium cardiac fibrosis and reducing the cardiomyocyte apoptosis. Key words: Ultrasound-targeted microbubble destruction; Diabetic cardiomyopathy; Ventricular function, left; Nanoliposomes; Modified acidic fibroblast growth factor

Layer-specific speckle tracking analysis of left ventricular systolic function and synchrony in maintenance hemodialysis patients

BackgroundThis study investigated the value of layer-specific strain analysis by two-dimensional speckle tracking echocardiography (2D-STE) for evaluating left ventricular (LV) systolic function and synchrony in maintenance hemodialysis (MHD) patients.MethodsA total of 34 MHD patients and 35 healthy controls were enrolled in this study. Dynamic images were collected at the LV apical long-axis, the four- and two- chamber, and the LV short-axis views at the basal, middle, and apical segments. The layer-specific speckle tracking (LST) technique was used to analyze the longitudinal strain (LS) and circumferential strain (CS) of LV sub-endocardium, mid-myocardium, sub-epicardium, global longitudinal strain (GLS), global circumferential strain (GCS), the LV 17 segment time to peak LS (TTP), and the peak strain dispersion (PSD). The differences in these parameters were compared between control and MHD groups, and the correlation between PSD and each LS parameter was examined. The receiver operator characteristic (ROC) curve was used to evaluate the efficacy of three myocardial layer LS and CS in the assessment of LV systolic dysfunction in MHD patients.ResultsMHD patients had comparable left ventricular ejection fraction (LVEF), but significantly smaller LV GLS, GCS, and three-layer LS and CS compared to the control group. The three myocardial layer LS of the basal segment, middle segment, and apex segment was significantly reduced in the MHD patients compared to the normal subjects, while the three myocardial layer CS of the basal segment, middle segment, and apex segment was significantly reduced in the MHD patients compared to the normal subjects, except for the sub-endocardium of the middle and apex segment. MHD patients had significantly higher TTP of LV 17 segments and PSD compared to controls, and had delayed peak time in most segments. In addition, PSD of MHD patients was positively correlated with sub-endocardial and mid-myocardial LS and GLS, but not with sub-epicardial LS. The area under the curves (AUCs) of sub-endocardial, mid-myocardial, and sub-epicardial LS in MHD patients were 0.894, 0.852, and 0.870, respectively; the AUCs of sub-epicardial, mid-myocardial, and sub-endocardial CS were 0.852, 0.837, and 0.669, respectively.ConclusionsLST may detect early changes of all three-layer LS and CS and PSD in MHD patients, and is therefore a valuable tool to diagnose LV systolic dysfunction in MHD patients.

Echocardiographic Assessment of Left Bundle Branch–Related Strain Dyssynchrony: A Comparison With Tagged MRI

Recent studies have shown the efficacy of myocardial strain estimated using speckle tracking echocardiography (STE) in predicting response to cardiac resynchronisation therapy. This study focuses on circumferential strain patterns, comparing STE-acquired strains to tagged-magnetic resonance imaging (MRI-T). Second, the effect of regularisation was examined. Two-dimensional parasternal ultrasound (US) and MRI-T data were acquired in the left ventricular short-axis view of canines before (n = 8) and after (n = 9) left bunch branch block (LBBB) induction. US-based strain analysis was performed on Digital Imaging and Communications in Medicine data at the mid-level using three overall methods (“Commercial software,” “Basic block-matching,” “regularised block-matching”). Moreover, three regularisation approaches were implemented and compared. MRI-T analysis was performed using SinMod. Normalised regional circumferential strain curves, based on standard six or septal/lateral segments, were analysed and cross-correlated with MRI-T data. Systolic strain (SS) and septal rebound stretch (SRS) were calculated and compared. Overall agreement of normalised circumferential strain was good between all methods on a global and regional level. All STE methods showed a bias (≥4% strain) toward higher SS estimates. Pre-LBBB, septal and lateral segment correlation was excellent between the Basic (mean ρ = 0.96) and regularised (mean ρ = 0.97) methods and MRI-T. The Commercial method showed a significant discrepancy between the two walls (septal ρ = 0.94, lateral ρ = 0.68). Correlation with MRI-T reduced between pre- and post-LBBB (Commercial ρ = 0.79, Basic ρ = 0.82, mean regularised ρ = 0.86). Septal strain patterns and SRS varied with the STE software and type of regularisation, with all STE methods estimating non-zero SRS values pre-LBBB. Absolute values showed moderate agreement, with a bias for higher strain from STE. SRS varied with the type of software and extra regularisation applied. Open efforts are needed to understand the underlying causes of differences between STE methods before standardisation can be achieved. This is particularly important given the apparent clinical value of strain-based parameters such as SRS.

Early Left Ventricular Dysfunction Detected by Speckle Tracking in Long-Term Hemodialysis Patients with Valvular Calcification

Purpose: Cardiac valve calcification (VC) is very common in patients on hemodialysis. However, the definite effect of VC on left ventricular (LV) geometry and function in this population is unknown, especially when LV ejection fraction (LVEF) is normal. The aim of this study was to determine the effect of VC on LV geometry and function in long-term hemodialysis patients by conventional echocardiography and two-dimensional speckle tracking echocardiography (2D-STE). Methods: A total of 47 hemodialysis patients (2–3 times weekly for 5 years or more) were enrolled in this study. Cardiac VC was defined as bright echoes of more than 1 mm on one or more cusps of the aortic valve or mitral valve or mitral annulus using echocardiography as the screening method. LV longitudinal global strain (GLS) was assessed on the apical four-chamber view and calculated as the mean strain of 6 segments. LV global circumferential strain was acquired on the LV short axis view at the level of papillary muscles. Results: Twenty-five patients with VC had higher mean values of interventricular septum thickness, LV posterior wall thickness, LV mass index, relative wall thickness, and LV mass/end-diastolic volume than 22 patients without VC (p < 0.05, respectively), indicating more obvious LV hypertrophy (LVH). VC patients had higher mitral annular E/E′ values, especially at the septal side representing increased LV filling pressure compatible with diastolic dysfunction, while only the E/E′ ratio of the septal side was significantly different between the 2 groups (16.7 ± 4.1 vs. 12.3 ± 4.4, p < 0.01). When assessed by GLS, LV longitudinal systolic function was also lower in in patients with VC compared with those without VC (–0.18 ± 0.03 vs. –0.25 ± 0.04; p < 0.01). Conclusions: Cardiac VC diagnosed by echocardiography when it occurs in long-term hemodialysis patients may indicate more severe LVH, myocardial damage, and worse heart function in comparison to those without VC. Tissue Doppler imaging and 2D-STE can detect the subtle change of heart function in this population in the early stage of LV dysfunction when LVEF is normal.

2D Speckle Tracking to Assess Left Ventricular Function in a Model of Ex Vivo Heart Perfusion

2D speckle tracking echocardiography (STE) is an emerging technology to evaluate left ventricular (LV) function and assesses myocardial fibers deformation [1]. Longitudinal shortening of LV fibers in apical views defines global longitudinal strain (GLS) and circumferential shortening in LV short axis views global circumferential strain (GCS). Ex Vivo Heart Perfusion (EVHP) perfuses the heart and allows functional assessment before transplant [2]. We applied STE to evaluate LV performance during EVHP.

Atorvastatin Attenuates Myocardial Hypertrophy in Spontaneously Hypertensive Rats via the C/EBPβ/PGC-1α/UCP3 Pathway

Background/Aims: Many clinical and experimental studies have shown that treatment with statins could prevent myocardial hypertrophy and remodeling induced by hypertension and myocardial infarction. But the molecular mechanism was not clear. We aimed to investigate the beneficial effects of atorvastatin on hypertension-induced myocardial hypertrophy and remodeling in spontaneously hypertensive rats (SHR) with the hope of revealing other potential mechanisms or target pathways to interpret the pleiotropic effects of atorvastatin on myocardial hypertrophy. Methods: The male and age-matched animals were randomly divided into three groups: control group (8 WKY), SHR (8 rats) and intervention group (8 SHR). The SHR in intervention group were administered by oral gavage with atorvastatin (suspension in distilled water, 10 mg/Kg once a day) for 6 weeks, and the other two groups were administered by gavage with equal quantity distilled water. Blood pressure of rats was measured every weeks using a standard tail cuff sphygmomanometer. Left ventricular (LV) dimensions were measured from short-axis views of LV under M-mode tracings using Doppler echocardiograph. Cardiomyocyte apoptosis was assessed by the TUNEL assay. The protein expression of C/EBPβ, PGC-1α and UCP3 were detected by immunohistochemistry or Western blot analysis. Results: At the age of 16 weeks, the mean arterial pressure of rats in three groups were 103.6±6.1, 151.8±12.5 and 159.1±6.2 mmHg respectively, and there wasn’t statistically significant difference between the SHR and intervention groups. Staining with Masson’s trichrome demonstrated that the increased interstitial fibrosis of LV and ventricular remodeling in the SHR group were attenuated by atorvastatin treatment. Echocardiography examination exhibited that SHR with atorvastatin treatment showed an LV wall thickness that was obviously lower than that of water-treated SHR. In hypertrophic myocardium, accompanied by increasing C/EBPβ expression and the percentage of TUNEL-positive cells, the expression of Bcl-2/Bax ratio, PGC-1α and UCP3 were reduced, all of which could be abrogated by treatment with atorvastatin for 6 weeks. Conclusion: This study further confirmed that atorvastatin could attenuate myocardial hypertrophy and remodeling in SHR by inhibiting apoptosis and reversing changes in mitochondrial metabolism. The C/EBPβ/PGC-1α/UCP3 signaling pathway might also be important for elucidating the beneficial pleiotropic effects of atorvastatin on myocardial hypertrophy.

Analysis of left ventricular circumferential strain in patients with left bundle branch block by layer-specific speckle tracking imaging

Objective To evaluate the left ventricular systolic circumferential strain by layer-specific speckle tracking imaging in healthy volunteers and patients with left bundle branch block (LBBB). Methods Forty patients with LBBB were divided into two groups, LBBB1 group [left ventricular ejection fraction(LVEF≥50%] and LBBB2 group (LVEF<50%), and 25 healthy subjects were selected as the control group.High frame rate two-dimensional images were recorded from the left ventricular short-axis views at the levels of the mitral annulus, papillary muscle and apex respectively. The peak systolic circumferential strain of the endocardium, myocardium and epicardium were measured using layer-specific strain software. Results The circumferential strain of the epicardium and myocardium at the level of the apex showed a statistically significant difference between the LBBB1 group and the control group (P=0.004), while there was no statistically significant difference demonstrated at the levels of the mitral annulus and papillary muscle(P>0.01). The circumferential strain of the endocardium at the levels of the papillary muscle and apex showed a statistically significant difference between the LBBB1 group and the control group(P=0.000), while there was no statistically significant difference demonstrated at the level of the mitral annulus(P>0.01). The circumferential strain of the endocardium, myocardium and epicardium at the three short-axis view levels showed statistically significant differences between the LBBB2 group and the control or LBBB1 groups respectively(P=0.000). Conclusions The circumferential strain of the endocardium at the level of the apex can provide more information about disease prognosis, especially in LBBB patients with a LVEF of ≥50%. Key words: Echocardiography; Bundle branch block; Speckle tracking imaging; Circumferential strain

Evaluation of left ventricular systolic function after renal sympathetic denervation in beagles with heart failure by layer-specific two-dimensional speckle tracking imaging

Objective To assess the left ventricular systolic function after renal sympathetic denervation(RSD) in beagles with heart failure by layer-specific two-dimensional speckle tracking imaging. Methods Twenty-three beagles were randomly divided into control group (8 dogs), URSD group (8 dogs) and RSD group (7 dogs). Control group was implanted with pacemakers without pacing, URSD group was implanted with pacemakers and underwent 3 weeks of rapid right ventricular pacing, and RSD group underwent catheter-based RSD bilaterally and was simultaneously implanted with pacemakers. All standard measurements were obtained from the left ventricular short-axis views at the levels of mitral annulus, papillary muscle and apex, and apical four-chamber, two-chamber, and long-axis views. The peak systolic longitudinal strain and circumferential strain of each layer of the left ventricle were measured by layer-specific two-dimensional speckle tracking imaging. Results After 3 weeks, all of the dogs in both the URSD and RSD groups showed lower left ventricular diastolic and systolic function compared with those in the control group, however, the dogs in the RSD group had a higher LV ejection fraction (LVEF) than the dogs in the URSD group(P<0.05). Compared with the control group, the global longitudinal strain, circumferential strain and radial strain all decreased significantly in URSD and RSD groups. The longitudinal strain of endo- and mid-cardium and the circumferential strain in endo-cardium were significantly higher in RSD group than those in URSD group(P<0.05). Conclusions Myocardial systolic function is impaired in dogs with heart failure, layer-specific two-dimensional speckle tracking imaging can provide effective tools to assess the left ventricular systolic function. Renal sympathetic denervation can improve the myocardial systolic function in dogs with heart failure. Key words: Echocardiography; Renal sympathetic nerve; Catheter ablation; Ventricular function, left; Layer-specific speckle tracking imaging

Prevention of doxorubicin induced cardiomyopathy after delivery of modified acidic fibroblast growth factor by using ultrasound-targeted microbubble destruction: a preliminary experimental study

Objective To observe the preventive effects of doxorubicin-induced cardiomyopathy (DOX-CM) rats after delivery of modified acidic fibroblast growth factor (MaFGF) by using ultrasound-targeted microbubble destruction (UTMD). Methods Fifty male SD rats were randomly divided into five groups: ①Control group; ②DOX-CM group; ③MaFGF group; ④UTMD group; ⑤MaFGF+ UTMD group. ②~⑤groups were intraperitoneally injected with doxorubicin to induce DOX-CM and given the corresponding interventions. Six weeks after intervention, all rats were underwent conventional echocardiography and velocity vector imaging (VVI) exams. Left ventricular internal dimension-diastole (LVIDd), left ventricular internal dimension-systole (LVIDs), left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were measured using conventional echocardiography. The segmental mean peak systolic radial velocity (Vs), systolic radial strain (Sr), and systolic radial strain rate (SRr) of six walls at the papillary muscle level were measured in left ventricular short-axis view by VVI. At last, myocardial tissues of all rats were stained with HE to observe the myocardial tissue morphology and with Van Gieson (VG) to calculate the collagen volume fractions (CVF). Results Six weeks after intervention, heart weight/body weight (HW/BW), LVIDs and LVIDd of MaFGF+ UTMD group were significantly decreased compared with those of DOX-CM group(P<0.05), while the LVEF, LVFS, Vs, Sc and Sr were significantly increased (P<0.05). Van Gieson stains showed that the collagen volume fractions (CVF) of DOX-CM groups significantly increased compared with that of the control group (P<0.01), while the CVF of MaFGF+ UTMD groups significantly decreased (P<0.01). Conclusions Delivery of MaFGF to myocardium in DOX-CM rats by UTMD could retard the formation of myocardial fibrosis and effectively protect the left ventricular function of DOX-CM rats. Key words: Echocardiography; Microbubbles; Acidic fibroblast growth factor; Cardiomyopathy; Doxorubicin

Improvement of left ventricular myocardial perfusion after acidic fibroblast growth factor delivered by using ultrasound-targeted microbubble destruction in rats with diabetic cardiomyopathy: an preliminary study

Objective To investigate the protective effects of left ventricular myocardial perfusion after delivery of acidic fibroblast growth factor (aFGF) in rats with diabetic cardiomyopathy (DCM) by using ultrasound-targeted microbubble destruction (UTMD) with real-time myocardial contrast echocardiography(RT-MCE). Methods Among 64 male SD rats, 52 rats were randomly selected and were induced DCM by streptozotocin through intraperitoneal injecting, the other rats as normal control group. DCM rats were randomly divided into the DCM model group, aFGF only group, SonoVue-aFGF group and the SonoVue-aFGF+ UTMD group in this study. The aFGF only group rats were injected with aFGF solution through tail vein, the SonoVue-aFGF group were injected with SonoVue-aFGF solution through tail vein and SonoVue-aFGF+ UTMD group rats were injected with SonoVue-aFGF solution through tail vein and using UTMD simultaneously. All rats underwent conventional echocardiography and RT-MCE exams before and 4 weeks after intervention. Left ventricular ejection fraction (LVEF) and left ventricular fraction shortening(LVFS) were measured by conventional echocardiography. The plateau intensity (A), initial slope of the curve (β) and myocardial blood flow (A×β) of left ventricular anterior wall at the papillary muscle level were measured in left ventricular short-axis view by RT-MCE. Results Before intervention, LVEF and LVFS in the DCM model group, aFGF only group, SonoVue-aFGF group and the SonoVue-aFGF+ UTMD group were significantly lower than in the normal control group (P 0.05), however A and A×β in the SonoVue-aFGF+ UTMD group were significantly increased than those in the DCM model group(P<0.01). Compared with the same group before intervention, A and A×β in the SonoVue-aFGF+ UTMD group were higher (P<0.05) and these in the DCM model group were lower during four weeks after intervention (P<0.05). Conclusions Acidic fibroblast growth factor delivered by using UTMD can improve the left ventricular myocardial perfusion in diabetic cardiomyopathy rats. Key words: Echocardiography; Diabetic cardiomyopathies; Fibroblast growth factor; Microbubbles; Ventricular function, left

A Novel Method for Sensitive Determination of Subclinical Left-Ventricular Systolic Dysfunction in Subjects With Obstructive Sleep Apnea

This study was to evaluate the subclinical left-ventricular (LV) systolic dysfunction with 2-dimensional speckle-tracking echocardiography in subjects with obstructive sleep apnea (OSA) with normal left ventricular ejection fraction and without any confounding disease that can cause myocardial dysfunction. Nineteen healthy individuals and 60 subjects with OSA were included in this study. According to the severity of disease, OSA subjects were examined in 3 groups: mild, moderate, and severe OSA. LV apical views (for longitudinal strain) and short-axis views (for circumferential strain) were acquired for evaluation. Three-layer longitudinal strain values and circumferential strain values were determined for each view, and averages of these were used in comparison with other groups. Three-layer longitudinal strain values of the subjects with OSA were lower than those of the healthy individuals, and these values were decreased along with the OSA severity. The difference was significant between severe OSA and all other groups. Three-layer circumferential strain values of the OSA subjects were lower than those of the healthy individuals, and the difference was significant between the control group and all other groups. The apnea hypopnea index was found to be correlated with the 3-layer longitudinal strain (r = -0.74, P < .001; r = -0.72, P < .001; r = -0.69, P = <.001). Three-layer longitudinal and circumferential LV systolic functions in OSA subjects with normal left ventricular ejection fraction are deteriorated in the subclinical stage. Two-dimensional speckle-tracking echocardiography can be used as an effective method in the determination of subclinical myocardial dysfunction in subjects with OSA.

Evaluation of left ventricular systolic function in different layers myocardium in patients with hypertrophic cardiomyopathy by two-dimensional speckle tracking echocardiography

Objective To assess the systolic function in left ventricular subendocardial myocardium, midmyocardium and subepicardial myocardium in patients with hypertrophic cardiomyopathy (HCM) by two-dimensional speckle tracking echocardiography. Methods A total of 32 patients with HCM and 32 healthy adults were included in the study. All standard measurements were obtained from the left ventricular short-axis views at the levels of mitral annulus, papillary muscle and apex, and apical four-chamber, two-chamber, and long-axis views. Two-dimensional speckle tracking imaging was employed. The global peak systolic radial strain, peak systolic longitudinal strain and circumferential strain of each layer of the left ventricle were measured. Results In patients with HCM and the control group, the peak systolic longitudinal strain and circumferential strain reduced from subendocardial myocardium to subepicardial myocardium. The global peak systolic radial strain in patients with HCM was significant lower than that in the control group. And in patients with HCM, peak systolic longitudinal strain in subendocardial myocardium, midmyocardium and subepicardial myocardium was significant lower than those in the control group. Conclusions Peak systolic longitudinal strain and circumferential strain are reduced from subendocardial myocardium to subepicardial myocardium.Myocardial systolic function is impaired in patients with HCM. In patients with HCM, longitudinal strain of each layer is lower, but circumferential strain is mainly reduced in midmyocardium and subepicardial myocardium compared with that in the control group. Key words: Echocardiography; Cardiomyopathy, hypertrophic; Ventricular function, left; Two-dimensional speckle tracking imaging

Right ventricular myocardial deformation patterns in children with congenital heart disease associated with right ventricular pressure overload.

Longitudinal wall motion of the right ventricle (RV) has been thoroughly studied in patients with RV dysfunction. However, circumferential strain of the RV free wall has yet to be investigated. Therefore, this study was conducted to assess the utility of RV free wall circumferential strain. Strain profile curves were obtained using speckle tracking echocardiography from the subcostal left ventricular (LV) short-axis view in 30 normal children (normal group) and 25 patients with RV pressure overload (RVO group). The time-strain curves of three individual segmental (anterior, lateral, and inferior segments) and global circumferential deformations were evaluated. RV ejection fraction (RVEF), RV systolic pressure (RVSP), and RV fractional area change obtained in the four-chamber view and LV short-axis view [RVFAC (4CH) and RVFAC (SAX), respectively] were measured, and their relationships with RV free wall deformation were assessed. In the normal group, circumferential strain was significantly lower in the anterior segment than in the other segments. The inferior segment had a significantly larger strain than the other segments in the RVO group. Circumferential strain was predominant over longitudinal RV free wall strain in the RVO group (-18.4 ± 3.9 vs. -14.2 ± 3.8%, respectively; P < 0.005), whereas no significant difference between them was observed in the normal group (-23.0 ± 3.9 vs. -22.4 ± 4.7%, respectively). Global circumferential strain had a significantly higher correlation with RVFAC (4CH), RVFAC (SAX), RVEF, and RVSP than global longitudinal strain (P < 0.05 for all). RV free wall circumferential strain provides better information about RV function than longitudinal strain in children with RVO.