Parasternal Long-axis View Research Articles

Gender difference in the relationship between epicardial adipose tissue and central obesity.

Body fat distribution is closely related to cardiovascular disease than the amount of total body fat itself. The epicardial adipose tissue (EAT) measured by transthoracic echocardiography represents central obesity. We hypothesized that the gender affected the link between EAT thickness and body fat distribution. We measured EAT thickness using transthoracic echocardiography and total body fat and regional body fat distribution using dual-energy X-ray absorptiometry (DXA) in 390 patients (250 males, 59 ± 11 year-old). The EAT thickness was measured on the free wall of the right ventricle at the end of the diastole on parasternal long-axis view of echocardiography. The median and mean EAT thickness of 390 patients were 4.0 mm and 4.2 ± 1.2 mm, respectively. The mean EAT thickness revealed positive correlation with truncal fat mass to total body fat mass ratio (FMtrunk/FMtotal, R = 0.291, P = .024). Subgroup analysis categorized by gender demonstrated the female group has stronger correlation of EAT thickness with fat distribution than the male group (male: R = 0.174, P = .006, female: R = 0.378, P < .001). EAT thickness is closely related to body fat distribution. Females showed a more significant correlation between EAT thickness and central fat accumulation than males. EAT thickness might be considered as a relevant parameter of central obesity, especially in females.

Echocardiographic estimates of stroke volume in healthy dogs: comparability, reference intervals, and reproducibility

Introduction: This study aimed to compare estimates of stroke volume (SV) from different anatomic sites and to generate reference intervals for indices such as shunt volume (ShuntVol) or regurgitant volume (RegVol) in a large sample of healthy dogs. Animals, Materials and MethodsNinety healthy dogs underwent an echocardiogram, where SV was assessed at the level of the pulmonary valve (SVPV), aortic valve (SVAV), mitral valve (SVMV), and left ventricle using the difference in end-diastolic volume and end-systolic volume from a right parasternal long-axis four-chamber view (SVLV_RPLx) and left apical four-chamber view (SVLV_Ap4Ch). Eight dogs underwent repeated echocardiograms by the same operator on three different days and by three different operators on the same day. Bland–Altman plots and 95% reference intervals were generated. Reproducibility was described using coefficients of variation and reproducibility coefficients. ResultsMean differences (95% limits of agreement) for ShuntVol (SVPV-SVAV), RegVolLV_RPLx (SVLV_RPLx-SVAV), RegVolLV_Ap4Ch (SVLV_Ap4Ch-SVAV), and RegVolMV (SVMV-SVAV) were as follows: −0.14 (−0.72, 0.44), −0.05 (−0.59, 0.48), −0.16 (−0.71, 0.39), and 0.12 (−0.76, 1.00) mL/kg, respectively. All but RegVolLV_RPLx showed significant (P<0.01) fixed bias. Reference intervals for ShuntVol, RegVolLV_RPLx, RegVolLV_Ap4Ch, and RegVolMV were as follows: −0.85-0.64, −0.65-0.58, −0.77-0.52, and −0.91-1.06 mL/kg, respectively. Intra-operator and interoperator coefficients of variation were lowest for SVAV and highest for SVMV and SVLV_AP4Ch. ConclusionsEchocardiographic estimates of SV are not interchangeable and can exhibit wide limits of agreement. Reference intervals help provide a frame of reference to assess disease severity in dogs with a shunting lesion (ShuntVol) and mitral regurgitation (RegVol).

Cardiac amyloidosis: a texture issue. a proof of concept study on quantification of granular sparkling in patients with transthyretin-related cardiac amyloidosis using radiomics and granulometry

Abstract Background Granular sparkling is a well-known echocardiographic feature found in patients with transthyretin-related cardiac amyloidosis (ATTR-CA). However, there is no objective technique for quantifying this feature, which therefore remains a qualitative, elusive and ultimately unreliable imaging characteristic. Recent evidence suggests that radiomics and, in particular, ultrasonomics could play an important role in the non-invasive tissue characterization of cardiomyopathies through the study of specific myocardial texture features. Purpose The aim of this study is to statistically and geometrically characterize granular sparkling as a volume-independent texture property of the myocardium in patients with ATTR-CA. Methods We retrospectively collected echocardiogram video-clips in parasternal long axis (PLAX) and 4-chamber (4CH) views of 229 patients with ATTR-CA, and 224 age- and gender-matched hypertensive patients without any known cardiac disease. From each video-clip, one end-diastole frame was extracted and annotated by an expert to identify a region-of-interest (ROI) within the interventricular septum. Left ventricle chamber masks were also extracted, and used as a brightness reference to enforce invariance w.r.t. the settings of the specific ultrasound system (Fig. 1). Because many established radiomic textural features are heavily volume-confounded, we analyzed the ROI texture by extracting a subset of volume-invariant radiomic features (i.e. ROI-independent), as well as morphological granulometry features. We then fitted a logistic regression classifier to discriminate between ATTR-CA and controls based on the computed textural features. Results 94 radiomic features were identified, of which 73 were volume-invariant. The texture-based classifier predicted the diagnosis with a cross-validated accuracy of 91%, a specificity of 90% and a sensitivity of 92% by utilizing 73 volume-invariant radiomic features on both PLAX and 4CH views (Fig. 2). The addition of granulometry and the further addition of 11 volume-confounded features and 9 shape features to the model did not significantly enhance its discriminative performance (Fig. 2). The top 10 volume-invariant discriminative features were largely consistent in PLAX and 4CH views (Fig. 2), with variables descriptive of greater heterogeneity (such as glszm_ZoneEntropy and glszm_RunEnNtropy) and a higher spatial rate of change (such as ngtdm_Complexity) in the texture of ATTR-CA frames as compared to control frames. Conclusions Our results confirm the ability of radiomics in detecting subtle differences in the myocardial texture of echocardiographic images between patients with ATTR-CA and hypertensive controls. High levels of accuracy are obtained with a purely texture-based, volume-independent set of features. These findings suggest that the diagnosis of ATTR-CA could be simplified and made earlier using a statistical model based on the extraction of radiomic features.Figure 1Figure 2

Deep learning for fully automated echocardiographic measurements of left ventricular wall thickness and chamber dimensions in the parasternal long-axis view

Abstract Background Accurate quantification of left ventricular (LV) wall thickness and chamber dimensions in the echocardiographic parasternal long-axis view (PLAX) is crucial for clinical decisions in patients with heart disease. However, there is a need for more reproducible and time-efficient methods. Fully automated deep learning (DL)-based methods could address this need. Purpose To develop a DL-based method for fully automated measurements of LV wall thickness and chamber dimensions in PLAX, validate its performance in a large population cohort, and evaluate its capacity to differentiate between hypertensive and normotensive groups. Methods DL networks were trained on PLAX recordings from 207 subjects. The DL method performed cardiac segmentation, timing of end-systole and end-diastole, and measured LV wall thickness and chamber dimensions in PLAX. The model was validated in a large populational echocardiography dataset including a subset with test-retest evaluation. Agreement with expert reference measurements, test-retest reproducibility, and comparison of normotensive and hypertensive (defined as those on hypertensive medication or with systolic blood pressure &amp;gt;160 mmHg) groups were evaluated. Results In the populational study of 2047 subjects, the novel DL method demonstrated a feasibility of 97.6%. Strong agreement was observed between the automated DL method and expert readers in measuring end-diastolic septal thickness, posterior wall thickness, and LV diameter (bias 0.1 mm, 0.2 mm, and 2.2 mm, respectively, Figure 1). In a test-retest dataset (n=40, with 2 recordings per patient and 4 readers), the novel DL method displayed improved reproducibility compared to inter-reader measurements, with minimal detectable change for interventricular septal diameter 2.2 mm versus 2.6 mm, posterior wall diameter 1.2 mm versus 2.5 mm, and LV diameter 5.0 mm versus 6.3 mm (Figure 2). The DL method measured significantly wider septal diameter in the hypertensive group compared to normotensive group (p&amp;lt;0.001). Mean analysis time for wall thickness and chamber dimensions using the DL method was 1.2 seconds. Conclusion The novel DL method accurately measured LV wall thickness and chamber dimensions in the PLAX view, and demonstrated improved test-retest reproducibility compared to experienced echocardiographers. Additionally, it was able to detect significantly wider septal diameters in the hypertensive population. By providing fast and reliable measurements in retrospective data, and with potential for real-time measurements during image acquisition, this DL method has the potential to improve the yield, efficiency, and workflow in echocardiography.Bland-Altman posterior wall diameterTest-retest posterior wall diameter

Left ventricular hypertrophy, wall thickness, and histological myocyte alteration in end-stage heart failure: a call for a standard definition

Abstract Objective This study aimed to examine the relationship between different left ventricular hypertrophy (LVH) classification criteria according to the American Society of Echocardiography (ASE), and anatomical measurement of LV wall thickness (LVWT) and histological evidence of myocyte hypertrophy. Methods Data from 146 consecutive patients (47 years; 75% were male) who have undergone heart transplantation were analysed. Fixed ventricles were dissected and measured in weight after both atria, great vessels, and epicardial fat were removed. The fixed biventricular weight was calculated as 87% of total weight (the effect of fixed formalin reduced the total weight by 3%). Anatomical LVWT was measured with a ruler at LV free wall where maximal thickness is located. A comprehensive echocardiogram was performed in all patients before heart transplantation. LVM and relative wall thickness (RWT) (2 PWT/LVEDD) were measured by M-mode echocardiography in parasternal long-axis view. Patients were considered to have LVH when the LVM index exceeds 95 g/m2 in women and exceeds 115 g/m2 in men. Patients were considered to have concentric LVH when RWT &amp;gt; 0.42. LVWT was measured using 2D echocardiography perpendicular to the LV long axis. Results Of 146 explanted hearts, dilated cardiomyopathy (CM), cardiac amyloid, and hypertrophic CM were diagnosed in 53 (47%), 1 (1%), and 8 (5%) patients, respectively. Anatomic ventricular mass correlated with echocardiographic LVM (r=0.5, p &amp;lt; 0.01). Anatomic LVWT modestly correlated with echocardiographic LVWT (r=0.2, p=0.01). Of 146 patients, echocardiographic normal LV geometry, concentric LV remodelling, concentric LVH, and eccentric LVH were present in 22 (15%), 6 (4%), 14 (10%), and 104 (71%), respectively. Increased LVWT (≥ 13 mm) assessed by 2-D echocardiography was present in normal LV geometry (5%), concentric LV remodelling (5%), concentric LVH (57%), and eccentric LVH (33%) (p &amp;lt;0.001) in those classified by ASE guidelines. Anatomic LVWT (≥ 13 mm) was present in normal LV geometry (14%), concentric LV remodelling 5%), concentric LVH (14%), and eccentric LVH (80%) (p &amp;lt;0.001) in those classified by ASE guidelines. Histological myocyte hypertrophy was present in normal LV geometry (12%), concentric LV remodelling (2%), concentric LVH (11%), and eccentric LVH (70%) (p &amp;lt;0.001) in those classified by ASE guidelines. Conclusions 2D-derived echocardiographic increased LVWT in patients with LVH defined by increased LVM index was present in approximately 30-50%. Furthermore, anatomical increased LVWT in those with LVH classified by ASE guidelines was present in a varying range of 10-70%. Patients with concentric LVH had a low prevalence of histological myocyte hypertrophy (approximately 10%). Inconsistencies in classification methods reveal the need for more robust LVH terminologies and definition that is consistent across cardiac imaging and anatomico-pathological examination, particularly in patients with CM.

Tissue Doppler Right Ventricle Myocardial Performance Index (TDI RV-MPI) Versus Tricuspid Annular Plane Systolic Excursion (TAPSE) in Evaluation of RV dysfunction in Patients with or without LV dysfunction

Introduction: Cardiovascular disease remains a leading cause of death. Right ventricular (RV) function is a strong predictor of outcome in many cardiovascular diseases, but its significance is often neglected. It has often been coined “the forgotten chamber. RV dysfunction may be secondary to left ventricle (LV) dysfunction as a consequence of “Ventricular Interdependence”. As RV dysfunction is associated with high in-hospital morbidity and mortality, early reorganization of RV dysfunction is warranted; but until today it remains a challenging task because of complex structure and asymmetric shape of RV. Objective: Our objective was to compare the efficacy of Tissue Doppler Right Ventricle Myocardial Performance Index (TDI RV-MPI) with Tricuspid Annular Plane Systolic Excursion (TAPSE), as a predictor of RV Systolic dysfunction. Methods: This was a cross-sectional study in patients undergoing comprehensive Transthoracic Echocardiography for any indication. Our aim was to compare Tissue Doppler Right ventricle Myocardial Performance Index (TDI RV-MPI) with TAPSE to predict RV function in patients with or without LV dysfunction .The current study recruited 100 patients who presented to the Cardiology Clinic of Lab Aid Cardiac Hospital. In addition to calculation of conventional, quantitative LVEF done in 2D guided M-mode in Para-sternal long-axis view, RV function was assessed in all subjects by measurement of Tricuspid Annular Plane Systolic Excursion (TAPSE) &amp; Tissue Doppler RV Myocardial Performance Index (TDI RV-MPI). Both were compared in prediction of RV dysfunction in patients with or without LV systolic dysfunction Results: RV dysfunction was found in subjects with LV dysfunction by both TAPSE &amp; TDI RV -MPI. RV dysfunction increased with reducing left ventricular ejection fraction. Normal TAPSE (~24 mm) was evidence of normal TDI RV-MPI (0.2594±0.03269, P&lt;.001), consistent with normal RV function. Of note, reduced TAPSE (~12 mm) was at the same time was evidence of increased TDI RV-MPI (0.7550±0.06351, P&lt;.001), suggestive of RV dysfunction. Simultaneously normal LVEF (~ 55%) was evidence of normal TAPSE (22±1.582 mm, P&lt;.001) &amp; normal TDI RV-MPI (0.25±.0509, P&lt;.001). Reduced LVEF (~25%) was at the same time, evidence of reduced TAPSE (15.50±3.317 mm, P&lt;.001) &amp; increased TDI RV-MPI (0.66±.1150, P&lt;.001). A statistically significant negative correlation of TDI RV-MPI (r=-0.927) was observed with TAPSE (p&lt;0.001). Also statistically significant negative correlation of TDI RV-MPI (r=-0.798) and significant positive correlation of TAPSE (r=0.813) were observed with LVEF (p&lt;0.001). In the analysis TDI RV-MPI maintained significant correlation with both LVEF &amp; TAPSE. In linear regression analysis TAPSE &amp; LVEF were significant independent predictor of TDI RV-MPI. Most important determinants of TDI RV-MPI was TAPSE (R=0.927, p&lt;0.001) . Conclusion: This study demonstrated that in patients with LV dysfunction there was RV dysfunction due to ‘ventricular interdependence’ as detected by both TAPSE &amp; TDI RV-MPI. TDI RV-MPI is a simple, sensitive, reproducible, noninvasive, non-geometirc echocadiographic parameter to provide global assessment of systolic and diastolic function of RV. It has the ability to detect RV dysfunction at an early stage, so as to reduce morbidity and mortality in these patients. It is evident that TDI RV-MPI can be a surrogate of TAPSE even with superior efficacy in RV functional assessment maintaining close relation with LVEF. These observations could guide decision making in daily clinical practice. Bangladesh Crit Care J September 2024; 12 (2): 105-112

Assessment of left atrial function using two-dimensional speckle tracking echocardiography in cryptogenic stroke patients.

Cryptogenic cerebrovascular stroke can be defined as an ischemic stroke that lacks a clear cause, even after a thorough evaluation. It should be distinguished from the embolic stroke of undetermined source (ESUS), a subgroup that includes cardio-embolic sources. This study aims to assess left atrial function through two-dimensional speckle tracking echocardiography (2D-STE) to determine its potential association with cryptogenic stroke andits predictive value for subclinical atrial fibrillation (AF). Our prospective cohort study involved 62 patients with unexplained cerebrovascular stroke or TIA, regardless of gender. Following TEE assessments, 22 patients were excluded due to identified sources of cardio-embolism. The remaining 40 participants were clustered into Group I. Group II, consisted of 40 healthy individuals without significant medical history, served as a control group. Both groups underwent two-dimensional trans-thoracic echocardiography and speckle tracking echocardiography. LA dysfunction parameters exhibited significant differences between Group I and Group II. LV diastolic dysfunction, LAVI, LAEF, and LASr were notably affected in Group I. At the same time, LA diameter in the parasternal long-axis view (PLAX) displayed a significant difference with a p value of 0.001. Within Group I, 14 patients experienced AF episodes (Group Ia, 35%); while, the remaining 26 were categorized as Group Ib (65%). LV diastolic dysfunction displayed a p value < 0.011; while, LAVI, LAEF, and LASr exhibited considerable differences with p values < 0.0001. However, the LA diameter showed no significant variation between the two groups. LASr emerged as the most sensitive and specific parameter for predicting AF, with a cutoff point of ≤ 24.5% and a p value < 0.0001. LAEF showed a cutoff point of ≤ 40.5% and a p value of 0.011. Meanwhile, LAVI demonstrated the lowest sensitivity and specificity, with a mean cutoff point of ≥ 38.5ml/m2 and a p value of 0.003. 2D-STE is crucial for assessing LA dysfunction as a potential cryptogenic stroke cause after TEE and ruling out cardio-embolism sources. LASr serves as a key LA cardiopathy indicator, even preceding AF. LASr independently poses an AF risk. While LAEF and LAVI are significant LA dysfunction parameters and AF predictors, they exhibit lower sensitivity and specificity than LASr.

Prevalence of Diastolic and Systolic Mitral Annular Disjunction in Patients With Mitral Valve Prolapse

Mitral annular disjunction (MAD) is commonly evaluated at end-systole. However, a systolic-only disjunction is merely apparent and two distinct phenotypes have been identified: True-MAD (atrial displacement of the posterior leaflet in diastole and systole) and Pseudo-MAD (apparent displacement in systole only). The prevalence of True-MAD and Pseudo-MAD in mitral valve prolapse (MVP) is not known. Aim of this study was to assess the prevalence of True-MAD and Pseudo-MAD in myxomatous MVP patients by transthoracic echocardiography (TTE) and to validate TTE compared to cardiac magnetic resonance (CMR) (reference standards). Consecutive patients who underwent TTE for MVP were included. Mitral annular phenotype was evaluated in TTE parasternal long-axis view. Accuracy (against CMR) and intra/inter rater reliability of TTE were also assessed. Six-hundred-three consecutive patients were included. The prevalence of True-MAD and Pseudo-MAD was 7% (42) and 37% (221) (p<0.05), respectively. Accordingly, 221 of 263 (84%) patients classically classified as "MAD" would have been reclassified as Pseudo-MAD. Pseudo-MAD prevalence and systolic length increased with higher mitral regurgitation (MR) severity (23% for mild MR, 36% for moderate MR, 44% for severe MR (p<0.05); 6 ± 2 mm for mild MR; 8 ± 2 mm for moderate MR; 10 ± 2mm for severe MR (p<0.05), while True-MAD prevalence was consistent across MR grades. Pseudo-MAD was linked to systolic curling and Pickelhaube. TTE showed an overall accuracy of 0.89 (Cohen k 0.80), a substantial inter-rater agreement of 0.87 (k 0.76) and an almost perfect intra-rater agreement of 0.93 (k 0.85). True-MAD, unlike Pseudo-MAD, is rare in patients with MVP. Pseudo-MAD is associated with the grade of MR and other echocardiographic features of advanced myxomatous degeneration. TTE is an accurate and reliable first line method to assess mitral annulus morphology in MVP.

Left atrial fractional shortening in cats: a comparison between two echocardiographic views

Introduction/objectivesLeft atrial fractional shortening (LAFS%) is a widely used index of left atrial systolic function in cats that has been shown to predict development of hypertrophic cardiomyopathy (HCM) and cardiac mortality. It can be determined by two methods: from an M-mode right parasternal short-axis view (LAFS%RPSA-MM) or two-dimensional right parasternal long-axis four-chamber view (LAFS%RPLA-2D). We aimed to assess the agreement between LAFS%RPSA-MM and LAFS%RPLA-2D in cats and to evaluate the correlation between LAFS%RPSA-MM and LAFS%RPLA-2D and left ventricular systolic performance. Animals, materials, and methodsOne hundred and seventeen cats were enrolled in the study: 40 control, 41 HCM stage B (asymptomatic), and 36 HCM stage C (symptomatic) cats. This was a retrospective case–control study. Bland–Altman analysis was used to assess agreement between LAFS%RPSA-MM and LAFS%RPLA-2D across the whole cohort and in cats with asymptomatic and symptomatic HCM. Correlation analysis was used to assess associations between LAFS% methods and forward aortic flow, left ventricular fractional shortening, and aortic root motion. ResultsThe LAFS% determined by LAFS%RPSA-MM and LAFS%RPLA-2D was similar (P=0.8), but Bland–Altman analysis showed wide limits of agreement between methods. There was a good correlation between LAFS%RPSA-MM and LAFS%RPLA-2D and aortic root motion (r = 0.78 and r = 0.71, respectively) and a fair correlation with left ventricular fractional shortening (r = 0.31 and r = 0.29, respectively). None of the methods showed a correlation with indices of aortic flow. ConclusionsOur study suggests a poor agreement between LAFS%RPSA-MM and LAFS%RPLA-2D, and thus, these methods should not be used interchangeably. Both echocardiographic methods showed good correlation with aortic root motion.

Assessment of an Artificial Intelligence Tool for Estimating Left Ventricular Ejection Fraction in Echocardiograms from Apical and Parasternal Long-Axis Views.

This work aims to evaluate the performance of a new artificial intelligence tool (ExoAI) to compute the left ventricular ejection fraction (LVEF) in echocardiograms of the apical and parasternal long axis (PLAX) views. We retrospectively gathered echocardiograms from 441 individual patients (70% male, age: 67.3 ± 15.3, weight: 87.7 ± 25.4, BMI: 29.5 ± 7.4) and computed the ejection fraction in each echocardiogram using the ExoAI algorithm. We compared its performance against the ejection fraction from the clinical report. ExoAI achieved a root mean squared error of 7.58% in A2C, 7.45% in A4C, and 7.29% in PLAX, and correlations of 0.79, 0.75, and 0.89, respectively. As for the detection of low EF values (EF < 50%), ExoAI achieved an accuracy of 83% in A2C, 80% in A4C, and 91% in PLAX. Our results suggest that ExoAI effectively estimates the LVEF and it is an effective tool for estimating abnormal ejection fraction values (EF < 50%). Importantly, the PLAX view allows for the estimation of the ejection fraction when it is not feasible to acquire apical views (e.g., in ICU settings where it is not possible to move the patient to obtain an apical scan).

Echocardiographic evaluation of left atrial volume and comparative analysis to left atrial to aortic root ratio in premature neonates and infants with patent ductus arteriosus.

Left atrium to aortic root ratio (LA/Ao) is an echocardiographic marker of hemodynamically significant patent ductus arteriosus (PDA). Since 2-dimensional measurement of the ratio is geometrically limited, left atrial volume (LAV) which has 3-dimensional characteristics was investigated. The aim of this study was to determine a correlation between LA/Ao ratio and LAV as well as holodiastolic flow reversal in preterm neonates with and without a PDA. A retrospective evaluation of neonates with and without PDA was performed. Targeted neonatal echocardiography evaluation of LA/Ao and LAV was measured from parasternal long-axis view and the apical 4 and 2-chamber views, respectively. Univariate and linear regression analysis were performed. 200 patients were included of whom 158 (79.0%) had a PDA shunt. The median gestational age at the time of echo was 27.4weeks (IQR: 25.7-29.4weeks). The median LA/Ao ratio was 1.51 (IQR: 1.26-1.83) and median LAV indexed to weight was .91mL/kg (IQR:.65-1.18mL/kg). There was a significant correlation between LA/Ao and LAV indexed to weight in the PDA group (r2=.080, p=.0003). LA/Ao ratio and LAV indexed to weight differed significantly between those with diastolic flow reversal versus no-flow reversal (LA/Ao, p=.003; LAV, p=.001). This study demonstrated a significant correlation between LA/Ao and LAV in preterm infants with PDA, with greater magnitude of discordance for LAV. The power of LAV versus LA/Ao in monitoring hemodynamically significant PDA requires prospective evaluation.

Machine Learning and Deep Learning Methods for Fast and Accurate Assessment of Transthoracic Echocardiogram Image Quality.

High-quality echocardiogram images are the cornerstone of accurate and reliable measurements of the heart. Therefore, this study aimed to develop, validate and compare machine learning and deep learning algorithms for accurate and automated assessment of transthoracic echocardiogram image quality. In total, 4090 single-frame two-dimensional transthoracic echocardiogram images were used from apical 4-chamber, apical 2-chamber and parasternal long-axis views sampled from 3530 adult patients. The data were extracted from CAMUS and Unity Imaging open-source datasets. For every raw image, additional grayscale block histograms were developed. For block histogram datasets, six classic machine learning algorithms were tested. Moreover, convolutional neural networks based on the pre-trained EfficientNetB4 architecture were developed for raw image datasets. Classic machine learning algorithms predicted image quality with 0.74 to 0.92 accuracy (AUC 0.81 to 0.96), whereas convolutional neural networks achieved between 0.74 and 0.89 prediction accuracy (AUC 0.79 to 0.95). Both approaches are accurate methods of echocardiogram image quality assessment. Moreover, this study is a proof of concept of a novel method of training classic machine learning algorithms on block histograms calculated from raw images. Automated echocardiogram image quality assessment methods may provide additional relevant information to the echocardiographer in daily clinical practice and improve reliability in clinical decision making.

Exploring heart dissection techniques for enhancing anatomical education: a pilot study to replicate transthoracic echocardiography.

For novice learners, converting two-dimensional (2D) images of echocardiography to three-dimensional (3D) cardiac structures is deemed challenging. This study aimed to develop an accurate dissection method of the heart to reproduce the transthoracic echocardiographic views on cadavers and elucidate new educational methods in human anatomy dissection courses. A total of 18 hearts were used in this study. After reflecting the anterior thoracic wall inferiorly, the hearts were excised from embalmed cadavers. Thereafter, three landmarks were set on the heart for each plane of the incision, and the hearts were incised to observe the three different echocardiographic views, which include the apical four-chamber view (A4C), parasternal long axis (PLAX) view, and parasternal short axis (PSAX) view at the papillary muscle level. If all structures for observation during routine echocardiography are clearly observed in each view, a successful incision is considered. All procedures and incisions were performed by the medical students. After a successful incision, hearts were returned to the original position in the pericardial sac for further observation. The success rates of incision for each view were 83.3% (5/6 success cases), 83.3% (5/6 success cases), and 66.7% (4/6 success cases) in the A4C view, PLAX view, and PSAX view at the papillary muscle level, respectively. This dissection method could probably be employed to reproduce transthoracic echocardiographic views on cadaveric hearts, which is beneficial for novice learners for a deeper understanding of the anatomy.

Development and Validation of a Deep-Learning Network for Detecting Congenital Heart Disease from Multi-View Multi-Modal Transthoracic Echocardiograms.

Early detection and treatment of congenital heart disease (CHD) can significantly improve the prognosis of children. However, inexperienced sonographers often face difficulties in recognizing CHD through transthoracic echocardiogram (TTE) images. In this study, 2-dimensional (2D) and Doppler TTEs of children collected from 2 clinical groups from Beijing Children's Hospital between 2018 and 2022 were analyzed, including views of apical 4 chamber, subxiphoid long-axis view of 2 atria, parasternal long-axis view of the left ventricle, parasternal short-axis view of aorta, and suprasternal long-axis view. A deep learning (DL) framework was developed to identify cardiac views, integrate information from various views and modalities, visualize the high-risk region, and predict the probability of the subject being normal or having an atrial septal defect (ASD) or a ventricular septaldefect (VSD). A total of 1,932 children (1,255 healthy controls, 292 ASDs, and 385 VSDs) were collected from 2 clinical groups. For view classification, the DL model reached a mean [SD] accuracy of 0.989 [0.001]. For CHD screening, the model using both 2D and Doppler TTEs with 5 views achieved a mean [SD] area under the receiver operating characteristic curve (AUC) of 0.996 [0.000] and an accuracy of 0.994 [0.002] for within-center evaluation while reaching a mean [SD] AUC of 0.990 [0.003] and an accuracy of 0.993 [0.001] for cross-center test set. For the classification of healthy, ASD, and VSD, the model reached the mean [SD] accuracy of 0.991 [0.002] and 0.986 [0.001] for within- and cross-center evaluation, respectively. The DL models aggregating TTEs with more modalities and scanning views attained superior performance to approximate that of experienced sonographers. The incorporation of multiple views and modalities of TTEs in the model enables accurate identification of children with CHD in a noninvasive manner, suggesting the potential to enhance CHD detection performance and simplify the screening process.

Is myocardial fibrosis appropriately assessed by 2D strain derived integrated backscatter?

Abstract Introduction Calibrated integrated backscatter (cIB) may be obtained from bidimensional (2D) strain echocardiography as a quantification measurement of myocardial ultrasound reflectivity. Increased collagen content of the myocardium modifies tissue reflectivity and cIB is suggested as a marker of left ventricular (LV) fibrosis. However, its diagnostic accuracy is not fully established. Aim To assess the correlation between cIB by 2D strain and LV myocardial fibrosis (MF), as evaluated by non-invasive imaging and histopathology. Methods Correlation study from a cohort of 157 patients with severe symptomatic aortic stenosis (AS) referred for surgical aortic valve replacement (AVR). Patients with complete preoperative transthoracic echocardiography, cardiac magnetic resonance (CMR) and endomyocardial biopsy (EMB) obtained from the anterior basal septum at the time of AVR were selected. Two groups of 30 patients were evaluated, with and without late gadolinium enhancement (LGE) at CMR. Integrated Backscatter was obtained at QRS peak in decibels (dB) from both parasternal long axis (PLAX) and apical-three-chamber (A3C) cine clips at Qanalysis. cIB was calculated by subtracting the pericardial intensity from the average of the anteroseptal and basal inferolateral wall values. Correlation analysis was performed for the whole group of patients with global and segmental (anterior basal septum) values of native T1 and extracellular volume (ECV), and EMB collagen volume fraction (CVF) from Masson´s Trichrome staining. IBS values were compared in both group of patients. Results 60 patients (74 [36-74] years, 45% male) with high gradient (mean gradient: 63±20mmHg), normal flow (45±10mL/m2), preserved ejection fraction (60±9%) AS were included. Basal septal cIB was –9.17±9.45dB and –17.45 (–31.2–10.95) dB from A3C and PLAX views, respectively. These indexes did not correlate with basal septum thickness or global LV mass. Absolute and cIB did not correlate neither with global and regional T1 and ECV values, nor with CVF at EMB. These were not significantly different in both groups of patients and there was no correlation between cIB values and mass of replacement MF in patients with LGE. Conclusion In these cohort of patients with classical severe AS, there was no correlation of cIB with imaging markers of both replacement and diffuse MF. cIB also didn´t correlate with CVF at histopathology. These findings suggest that reflectivity indexes are not suitable for myocardial tissue characterization in this setting.

Veterinary echocardiographers' preferences for left atrial size assessment in cats: the BENEFIT project

Introduction/objectivesVeterinary echocardiographers' preferences for left atrial (LA) size assessment in cats have not been systematically investigated. The primary aim of this prospective exploratory study was to investigate echocardiographers' preferences concerning LA size assessment in cats. A secondary aim was to investigate echocardiographers' preferences for assessing LA size in subgroups based on geographic, demographic, and professional profiles. Animals, materials, and methodsAn online survey instrument was designed, verified, and distributed globally to veterinary echocardiographers. ResultsA total of 655 veterinary echocardiographers from six continents and 54 countries, working in specialty practice (56%) and in general practice (38%), provided data. Linear two-dimensional (2D) technique was favored by most echocardiographers (n = 612) for LA size assessment. Most commonly, respondents combined linear 2D with subjective assessment (n = 227), while 209 used linear 2D-based methods alone. Most echocardiographers using linear 2D-based methods preferred the right parasternal short-axis view and to index the LA to the aorta (Ao). Approximately 10% of the respondents obtained LA dimensions from a right parasternal long-axis four-chamber view. Approximately one-third of echocardiographers that made linear measurements from 2D echocardiograms shared the same preferences regarding cat position, acquisition view, indexing method and time point identification for the LA measurement. The responses were comparably homogeneous across geographic location, level of training, years performing echocardiography, and type of practice. Discussion/conclusionMost veterinary echocardiographers assessed LA size in cats using linear 2D echocardiography from a right parasternal short-axis view, and indexed LA to Ao. Respondents' preferences were similar over geographic, demographic, and professional backgrounds.

Natural shear wave measurements detect changes in operational stiffness induced by mechanical ventilation in sheep

Abstract Shear wave elastography (SWE) has the potential to non-invasively measure myocardial stiffness, based on the propagation speed of shear waves traveling through the myocardium after valve closure. However, shear wave propagation speed (SWS) is related to the operational stiffness of the heart, which is defined by the slope of the end-diastolic stress-strain relationship at the operating volume/pressure. Therefore, operational stiffness can be altered by both changes in intrinsic myocardial stiffness and myocardial loading conditions. We aimed to investigate whether SWE can detect differences in operational stiffness induced by loading changes during mechanical ventilation, and whether SWE combined with respiratory hold manoeuvres could detect an evolution in stiffness during the course of ischemic cardiomyopathy (ICM). We assessed SWS in 8 sedated and mechanically ventilated sheep: 1 healthy control, 3 within 8 weeks, and 4 after at least 16 weeks following left coronary artery ligation (early vs. late ICM). Left ventricular parasternal long-axis views were acquired with a state-of-the-art ultrasound scanner with high frame rate technology (&amp;gt; 1100 Hz). Shear waves after mitral valve closure were considered during an inspiratory hold at 30 cmH2O and 15 cmH2O and expiratory hold at 0 cmH2O (atmospheric pressure). We used linear regression to assess the trend of the SWS during ventilation manoeuvres per animal and a two-tailed Student’s T-test to assess changes between ICM stages and their respective response to ventilation manoeuvres. In all but one sheep, SWS declined with higher inspiratory pressures (see fig. 1), possibly due to a reduction in preload at higher inspiratory pressures resulting in a shift towards a reduced slope on the myocardial stress-strain relation. The sheep with a positive slope was excluded from further analyses. SWS during expiratory hold at atmospheric pressure was 3.4 m/s in the healthy control and was significantly lower in early vs. late ICM (mean±SD 4.0±0.6 vs. 9.0±1.7 m/s; p=0.007). Furthermore, the change in SWS was larger in late vs. early ICM (slope of regression line -0.16 vs. -0.05 m/s/cmH2O; p=0.03). These observations suggest loading on a steeper part of the end-diastolic stress strain relationship in late ICM. In conclusion, our results suggest that SWE is able to detect differences in operational stiffness induced by mechanical ventilation. Secondly, SWE appears to distinguish between different time points in the course of ICM based on the magnitude of the SWS during expiratory hold at atmospheric pressure, but also on the magnitude of the SWS change during loading alterations induced by mechanical ventilation. Further work should assess whether SWE combined with respiratory hold manoeuvres could contribute to differentiate intrinsic from hemodynamic stiffening, and to exploit its full potential as a non-invasive bedside method for the assessment of operational stiffness.

Sitting maneuver to uncover latent left ventricular outflow tract obstruction in patients without hypertrophic cardiomyopathy

BackgroundLeft ventricular outflow tract obstruction [LVOTO; pressure gradient (PG) ≥30 mmHg] is observed in some patients without hypertrophic cardiomyopathy (HCM), and it may develop especially in older patients without HCM (non-HCM). The aim of this study is to investigate if the Valsalva or an upright sitting maneuver can unveil latent LVOTO in patients with non-HCM. MethodsA total of 33 non-HCM patients with a late peaking or dagger-shaped pulsed Doppler waveform of the LVOT and PG <30 mmHg were included. The Doppler flow velocity of the LVOT was measured at rest, after the Valsalva and a sitting maneuver. Peak PG of ≥30 mmHg after either maneuver was defined as latent LVOTO. The angle between the left ventricular septum and the aorta in the parasternal long-axis view and the apical three-chamber view was measured. ResultsTwenty (61 %) of the 33 patients (mean age 74 ± 9 years) were diagnosed with latent LVOTO. Of these, five (25 %) patients were diagnosed after both the Valsalva and sitting maneuver, and 15 (75 %) were diagnosed only after the sitting maneuver. The latent LVOTO group had a significantly smaller angle than the no-LVOTO group between the ventricular septum and the aorta in the parasternal long axis views (107 ± 8° vs. 117 ± 8°, p < 0.01). ConclusionThe sitting maneuver is better than the Valsalva maneuver in unveiling latent LVOTO in older, non-HCM patients.

Deep learning for automated left ventricular outflow tract diameter measurements in 2D echocardiography

BackgroundMeasurement of the left ventricular outflow tract diameter (LVOTd) in echocardiography is a common source of error when used to calculate the stroke volume. The aim of this study is to assess whether a deep learning (DL) model, trained on a clinical echocardiographic dataset, can perform automatic LVOTd measurements on par with expert cardiologists.MethodsData consisted of 649 consecutive transthoracic echocardiographic examinations of patients with coronary artery disease admitted to a university hospital. 1304 LVOTd measurements in the parasternal long axis (PLAX) and zoomed parasternal long axis views (ZPLAX) were collected, with each patient having 1–6 measurements per examination. Data quality control was performed by an expert cardiologist, and spatial geometry data was preserved for each LVOTd measurement to convert DL predictions into metric units. A convolutional neural network based on the U-Net was used as the DL model.ResultsThe mean absolute LVOTd error was 1.04 (95% confidence interval [CI] 0.90–1.19) mm for DL predictions on the test set. The mean relative LVOTd errors across all data subgroups ranged from 3.8 to 5.1% for the test set. Generally, the DL model had superior performance on the ZPLAX view compared to the PLAX view. DL model precision for patients with repeated LVOTd measurements had a mean coefficient of variation of 2.2 (95% CI 1.6–2.7) %, which was comparable to the clinicians for the test set.ConclusionDL for automatic LVOTd measurements in PLAX and ZPLAX views is feasible when trained on a limited clinical dataset. While the DL predicted LVOTd measurements were within the expected range of clinical inter-observer variability, the robustness of the DL model requires validation on independent datasets. Future experiments using temporal information and anatomical constraints could improve valvular identification and reduce outliers, which are challenges that must be addressed before clinical utilization.Graphical

E-Point Septal Separation: A Bedside Tool for Emergency Physician Assessment of Left Ventricular Ejection Fraction

Introduction: Rapid assessment of left ventricular ejection fraction (LVEF) may be critical among emergency department (ED) patients. This study examined the predictive relationship between bedside mitral-valve E-point septal separation (EPSS) measurements to the quantitative calculated LVEF. Objective: The aim of this study was to investigate the ability of a new index, namely the mitral valve E-Point Septal Separation (EPSS ) to predict the left ventricular (LV) systolic function. Methods: A prospective observational study was conducted on a sequential convenience sample of patients, receiving comprehensive Transthoracic Echocardiography (TTE). The current study recruited 100 patients who presented to the Cardiology Clinic of Lab Aid Cardiac Hospital. Echocardiographic examinations were performed to obtain 2D guided M-mode measurements of the EPSS in addition to calculation of conventional, quantitative LVEF. All the measurements were done in the Para-sternal long-axis view. A linear regression analysis was conducted to examine the relation of EPSS to the calculated LVEF from the comprehensive TTE. Results: Total 100 patients were enrolled in the study. It was found that there was a very significant negative correlation of EPSS with Calculated LVEF (r=--.766, p&lt;0.001). An EPSS ≥ 7 mm was evidence of reduced LVEF &lt;40%, ( p&lt;0.01). Of note an EPSS ≥ 12 mm correlates with severely decreased LV function, with an estimated LVEF of ≤ 30% (p&lt;0.01). As was shown by the results of the linear regression analysis, EPSS was a significant determinant of calculated LVEF (R=.766, p&lt;0.001). The results of the linear regression analysis indicated that the EPSS was an independent predictor of the LVEF. Conclusions: Measurements of EPSS were significantly associated with the calculated measurements of LVEF from comprehensive TTE. An EPSS measurement of &gt;7 mm was uniformly sensitive at identifying patients with reduced LVEF &amp; &gt;12 mm was uniformly sensitive at identifying patients with severely reduced LVEF. EPSS may allow certain clinicians, especially beginners and emergency department physicians, to assess the LVEF when other methods are not available or questionable. Bangladesh Crit Care J September 2023; 11 (2): 90-94