Parasternal Short Axis Research Articles

Fully automated quantification of cardiac chamber and function assessment in 2-D echocardiography: clinical feasibility of deep learning-based algorithms

We aimed to compare the segmentation performance of the current prominent deep learning (DL) algorithms with ground-truth segmentations and to validate the reproducibility of the manually created 2D echocardiographic four cardiac chamber ground-truth annotation. Recently emerged DL based fully-automated chamber segmentation and function assessment methods have shown great potential for future application in aiding image acquisition, quantification, and suggestion for diagnosis. However, the performance of current DL algorithms have not previously been compared with each other. In addition, the reproducibility of ground-truth annotations which are the basis of these algorithms have not yet been fully validated. We retrospectively enrolled 500 consecutive patients who underwent transthoracic echocardiogram (TTE) from December 2019 to December 2020. Simple U-net, Res-U-net, and Dense-U-net algorithms were compared for the segmentation performances and clinical indices such as left atrial volume (LAV), left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), LV mass, and ejection fraction (EF) were evaluated. The inter- and intra-observer variability analysis was performed by two expert sonographers for a randomly selected echocardiographic view in 100 patients (apical 2-chamber, apical 4-chamber, and parasternal short axis views). The overall performance of all DL methods was excellent [average dice similarity coefficient (DSC) 0.91 to 0.95 and average Intersection over union (IOU) 0.83 to 0.90], with the exception of LV wall area on PSAX view (average DSC of 0.83, IOU 0.72). In addition, there were no significant difference in clinical indices between ground truth and automated DL measurements. For inter- and intra-observer variability analysis, the overall intra observer reproducibility was excellent: LAV (ICC = 0.995), LVEDV (ICC = 0.996), LVESV (ICC = 0.997), LV mass (ICC = 0.991) and EF (ICC = 0.984). The inter-observer reproducibility was slightly lower as compared to intraobserver agreement: LAV (ICC = 0.976), LVEDV (ICC = 0.982), LVESV (ICC = 0.970), LV mass (ICC = 0.971), and EF (ICC = 0.899). The three current prominent DL-based fully automated methods are able to reliably perform four-chamber segmentation and quantification of clinical indices. Furthermore, we were able to validate the four cardiac chamber ground-truth annotation and demonstrate an overall excellent reproducibility, but still with some degree of inter-observer variability.

Validation of a deep learning algorithm identifying diagnostic quality cardiac ultrasound reference views during search phase

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): DESKi Background Transthoracic echocardiography requires long and demanding training. The use of deep learning algorithms for the identification of diagnostic quality reference views opens the way for assisting low-experienced operators. However, such algorithms have only been trained and validated on retrospective data extracted from daily hospital practice. Those retrospective data are the best clips selected by experts during each exam. Thus, the performance of those algorithms has not been evaluated on complete acquisitions, including the search phase, i.e. when the operator is moving the probe to reach the optimal position. Those search phases are not recorded in clinical practice. Purpose The objective of this study was to evaluate the performance of a deep learning algorithm that identifies diagnostic quality images for 7 echocardiographic reference views on a prospective dataset including search phases. Methods A retrospective dataset containing acquisitions extracted from daily hospital practice was created. The retrospective dataset was manually annotated by experts following quality criteria that were defined for 7 main reference views: parasternal long and short axis, apical 4, 2, and 3-chamber, subcostal 4-chamber and inferior vena cava. Each frame of the acquisitions was annotated by an expert and reviewed by a second expert. A deep learning model was trained on the retrospective dataset and evaluated with 5-fold cross-validation. In a prospective dataset, for each included patient and each reference view, operators recorded the entire acquisition, including the search phase. Acquisitions were manually annotated by 2 experts following the same quality criteria. The model trained on retrospective data was evaluated on this prospective dataset against manual experts’ annotations. Additionally, 3 experts annotated a subset of the prospective dataset to evaluate the inter-observer variability. Results 481,111 frames from 1,325 patients were annotated for the retrospective dataset. On the 5-fold cross-validation, the algorithm reached an average accuracy of 89.2 ± 0.7% per frame and an average F1-score of 87.9 ± 0.9% per frame. For the prospective dataset, 70 patients were included and 143,804 frames annotated. The average accuracy was 84.8 ± 5.0% per patient, and the average F1-score was 83.1 ± 8.7% per patient. The average inter-observer agreement rates, performed on 10 patients (23,390 frames), were between 82.8 ± 4.9% and 86.3 ± 6.2%. Conclusions We propose a deep learning algorithm that automatically identifies 7 of the most common reference views with diagnostic quality while achieving performance within the range of the inter-observer variability in acquisitions including search phases.

Abstract WP228: Normal Left Atrial Diameter Is Associated With Better Performance On A Telephone Cognition Screening Tool Among Ischemic Stroke Survivors

Background: Cardiac structure and function are important in determining ischemic stroke (IS) etiology, but whether there is an association with cognition post IS is unknown. Methods: IS patients admitted to Johns Hopkins Hospital (2017-2019) underwent transthoracic echocardiography. IS was classified (TOAST) by a masked reviewer. Parasternal short axis left atrial (LA) diameter was evaluated as a continuous variable with a spline at 4cm (normal ≤4cm versus enlarged >4cm); left ventricle ejection fraction (LVEF) was evaluated as a nonlinear continuous variable with two spline knots at 40% and 65%. Cognition was assessed by telephone using the Six Item Screener (SIS), which tests orientation (day, month, year) and recall (grass, paper, shoe) and was dichotomized into low (0-3, worse score) and high (4-6, better score), and conservatively imputing low category scores for non-answerers. Multivariable logistic regression determined the association of SIS category with LA or LVEF, each, adjusted for covariates. Results: Participants (N=119) were on average 60 (18-89) years, 60% male, and 59% Black. Mean LA diameter was 3.9cm ( SD =0.8) and mean LVEF 61.4% ( SD =10.5). For LA diameter ≤4cm, each 1cm increase was associated with 5.93 greater odds (95% CI=1.49-23.65) of scoring in the high SIS category, while for LA diameter >4cm each 1cm increase was associated with lower odds (OR=0.88, 95% CI=0.39-1.99) of scoring in the high SIS category (Figure 1). Decreased (OR=0.91, 95% CI=0.74-1.11), normal (OR=0.98, 95% CI=0.91-1.06) or hyperdynamic LVEF (OR=1.02, 95% CI=0.90-1.14) showed no relationship with SIS category. Conclusions: In this study, a 1cm change in LA diameter was significantly associated with a higher score on a telephone cognition screening test, if patients had a LA diameter within normal range, but without the same association with SIS if the LA diameter was >4cm. We cautiously suggest that LA function may be associated with cognition post-stroke.

Moderna Vaccine Induced Recurrent Myopericarditis

COVID-19 mRNA vaccine-related myocarditis and myopericarditis is a rare complication, with the US Centers for disease Control and Prevention reporting 4.2 per million females aged 12-29 years, dropping to 1.0 per million over 30, and exceptionally rare is recurrent myopericarditis requiring immunosuppressive therapy. We report a case of a 51-year-old female with no significant medical history presented to the emergency department with pleuritic chest pain, and progressive breathlessness 9 days after her first Moderna vaccine. Electrocardiography revealed widespread ST segment elevation with PR depression in the inferior leads. Her inflammatory markers were elevated with a C- reactive protein of 263. Transthoracic echocardiography revealed a moderate circumferential pericardial effusion with a maximum of 1.8cm adjacent to the lateral wall of the left ventricle in the parasternal short axis view and no evidence of tamponade physiology. The patient did not show initial response to anti-inflammatory therapy, and was commenced on steroid therapy, and subsequently immunosuppressive therapy, namely azathioprine, to manage disease activity. This case brings to light a rare but significant side effect of mRNA vaccine, and whilst this case should not impede vaccination efforts, it highlights that whilst the majority of patients get transient self-limiting myocardial inflammation, rare cases of prolonged myopericarditis may occur which may require prolonged immunosuppression.

OR4. Agreement between Transthoracic Echocardiography and Surgical Measurements of the Tricuspid Annulus Diameter

Abstract Aims The tricuspid annulus dilatation is an indication for tricuspid repair concomitant with mitral surgery. The distance between anteroseptal and anteroposterior commissure represents the direction of dilatation provided by surgical measurements. However, none of the standard views of two-dimensional transthoracic echocardiography (2D-TTE) intersect that plane and there is still a lack of study regarding the tricuspid annulus measurements by three-dimensional transthoracic echocardiography (3D-TTE). Therefore, this study aims to determine the agreement between the tricuspid annulus diameter measurement by transthoracic echocardiography and surgical measurement. Methods and Results 40 patients were included. Measurements of tricuspid annulus diameter by 2D-TTE and 3D-TTE were performed before surgery in parasternal right ventricle inflow (PRVI), parasternal short axis (PSAX), apical 4-chambers (A4C), and multiplanar analysis 3D-TTE views. Surgical measurements were performed during surgery. Agreement between the echocardiography and surgical measurements was analyzed using Bland-Altman and intraclass correlation analysis. Mean difference ± standard deviation (limits of agreement) and ICC of PRVI 2D-TTE vs surgical measurement were 1.35±5.02 mm (-8.48 - 11.18 mm), ICC 0.89, p < 0.001; PSAX 2D-TTE vs surgical measurement were 1.35±5.23 mm (-8.90 - 11.60 mm), ICC 0.88, p < 0.001; A4C 2D-TTE vs surgical measurement were 1.33±3.69 mm (-5.91 - 8.56 mm), ICC 0.93, p < 0.001; septolateral diameter 3D-TTE vs surgical measurements were 1.42±4.41 mm, (-7.22 - 10.06 mm), ICC 0.90, p < 0.001; anteroposterior diameter 3D-TTE vs surgical measurements were -2.695±7.43 mm (- 17.26 - 11.87 mm), ICC 0.68, p < 0.001. Conclusion A4C 2D-TTE and septolateral diameter 3D-TTE measurement have an excellent agreement with surgical measurement.

Abstract 10345: Video-Based Deep Learning Model for Automated Assessment of Ejection Fraction in Pediatric Patients

Introduction: Echocardiographic assessment of left ventricular (LV) systolic function by ejection fraction (EF) is crucial for diagnosis and monitoring in pediatric patients. EF requires manual tracing of the LV but measurement reproducibility is affected by diverse phenotypes, image quality, and operator skill. We sought to train a deep learning model (EchoNet-Peds) on a pediatric-specific video dataset to automatically segment the LV and estimate EF by 5/6 Area Length (AL) using two common views, the apical 4 chamber (A4C) and parasternal short axis (PSAX). Methods: EchoNet-Peds evaluated raw A4C and PSAX videos to segment the LV and predict the EF from the A4C and PSAX views. Eighty percent of the dataset was used for algorithm training, 10% for validation, and 10% for testing. We used the training set to predict the EF by AL, determined hyperparameters from the validation set, and reported results using 10-fold cross-validation on the test set. Results: The dataset included 1923 children (43% female) with 4400 echocardiogram studies. EFs ranged from 10% to 81% (61% ± 10.1) and ages from 0 to 18 years (10 ± 5.4 years). EchoNet-Peds achieved Dice Similarity Coefficients of 0.901 (0.895 - 0.907) and 0.887 (0.879 - 0.895) for segmenting the LV in A4C and PSAX views respectively. The A4C view predicts an EF by AL with an R2 of 0.73 (0.67 - 0.77) and the PSAX view predicts an R2 of 0.74 (0.70 - 0.77). Combining both predictions results in an overall R2 of 0.78 (0.74 - 0.81). The model performs well when stratified by sex, age, and body surface area (BSA), and improves in younger patients and lower BSA (Figure 1 b-d). Conclusions: EchoNet-Peds is the first demonstration that AI trained on a pediatric-specific dataset utilizing multiple views can accurately segment the LV and predict EF. The automated functionality of EchoNet-Peds can be used for real-time assessment of cardiac function despite pediatric heterogeneity.

Abstract 11887: High Agreement Between 2D and 3D Echocardiography in Measuring Dimensions of the Patent Ductus Arteriosus in Infants

Introduction: The patent ductus arteriosus (PDA) is a common lesion in infants. Two-dimensional echocardiography (2DE) is standard for PDA imaging. Three-dimensional echocardiography (3DE) is often used for complex anatomy and for procedural planning. Very limited data exist on use of 3DE of the PDA in infants despite its value in planning interventions. We aim to determine the agreement between 2DE and 3DE in measuring PDAs in infants. Hypothesis: Significant agreement exists between 2DE and 3DE for PDA measurements. Methods: Infants with a known PDA underwent 2DE and 3DE imaging by an IRB-approved protocol. Subjects were <1 year old, >32 weeks corrected gestation (CGA), >1kg, and clinically stable. Parasternal short axis (PSAX) and suprasternal notch (SSN) PDA images were taken. Two blinded observers measured the pulmonic (PA) and aortic (Ao) end of the PDA. Interobserver variability was assessed by interclass correlation (ICC), Bland-Altman (BA), and coefficient of variability (COA). 2DE to 3DE agreement was assessed by BA. Results: For 19 subjects acquired, median CGA 38.0 weeks (IQR 35.6-39.1), median weight 3.07kg (IQR 2.83-4.34). ICC for 2DE and 3DE in all views was >0.98 with narrow limits of agreement (LOA) (Table 1). BA showed low bias and narrow LOA. COA was <3.6%. Paired 2DE-3DE comparison had low bias and narrow LOA (Table 2). Conclusions: PDA measures by 2DE and 3DE have strong interobserver agreement. Paired 2DE-3DE measures show low bias and variability. A larger cohort will test agreement with variable subject size, ductal size & type, and compare to angiography. Preliminary data show promise for 3DE in future use for PDA procedural planning.

Prevalence of left ventricular systolic dysfunction by single echocardiographic view: towards an evidence-based point of care cardiac ultrasound scanning protocol.

Limited views are often obtained in the setting of cardiac ultrasound, however, the likelihood of missing left ventricular (LV) dysfunction based on a single view is not known. We sought to determine the echo views that were least likely to miss LV systolic dysfunction in consecutive transthoracic echocardiograms (TTEs). Structured data from TTEs performed at 2 hospitals from September 25, 2017, to January 15, 2019, were screened. Studies of interest were those with reported LV dysfunction. Views evaluated were the parasternal long-axis (PLAX), parasternal-short axis at mitral (PSAX M), papillary muscle (PSAX PM), and apical (PSAX A) levels, apical 2 (AP2), apical 3 (AP3), and apical 4 (AP4) chamber views. The probability that a view contained at least 1 abnormal segment was determined and analyzed with McNemar’s test for 21 adjusted pair-wise comparisons. There were 4102 TTE studies included for analysis. TTEs on males comprised 72.7% of studies with a mean LV ejection fraction of 42.8 ± 9.7%. The echo view with the greatest likelihood of encompassing an abnormal segment was the AP2 view with a prevalence of 93.4% (p < 0.001, compared to all other views). The PLAX view performed the worst with a prevalence of 82.5% (p < 0.015, compared to all other views). The best parasternal view for the detection of abnormality was the PSAX PM view at 90.4%. In conclusions, a single echo view will contain abnormal segments > 82% of the time in the setting of LV systolic dysfunction, with a prevalence of up to 93.4% in the apical windows.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10554-021-02460-4.

An Abnormal Echocardiogram and Telemetry Tracing in a Late Preterm Infant.

An Abnormal Echocardiogram and Telemetry Tracing in a Late Preterm Infant.

Classification of Echocardiogram View using A Convolutional Neural Network

The standard views in echocardiography capture distinct slices of the heart which can be used to assess cardiac function. Determining the view of a given echocardiogram is the first step for analysis. To automate this step, a deep network of the ResNet-18 architecture was used to classify between six standard views. The network parameters were pre-trained with the ImageNet database and prediction quality was assessed with a visualization tool known as gradient-weighted class activation mapping (Grad-CAM). The network was able to distinguish between three parasternal short axis views and three apical views to ~99\% accuracy. 10-fold cross validation showed a 97\%-98\% accuracy for the apical view subcategories (which included apical two-, three-, and four- chamber views). Grad-CAM images of these views highlighted features that were similar to those used by experts in manual classification. Parasternal short axis subcategories (which included apex level, mitral valve level, and papillary muscle level) had accuracies of 54\%-73\%. Grad-CAM images illustrate that the network classifies most parasternal short axis views as belonging to the papillary muscle level. Likely more images and incorporating time-dependent features would increase the parasternal short axis view accuracy. Overall, a convolutional neural network can be used to reliably classify echocardiogram views.

Adoptability and accuracy of point-of-care ultrasound in screening for valvular heart disease in the primary care setting.

Despite continued efforts, a majority of patients with valvular heart disease (VHD) remain undiagnosed and untreated. This study aimed to assess the adoptability and accuracy of point-of-care handheld echocardiographic assessments (POCE) in the primary care setting. Eleven previously untrained primary care providers were trained to use the Vscan Extend (GE, WI) POCE to assess VHD, left ventricular function (LVEF), and major extra-cardiac findings. Their assessments were compared to those of three blinded expert readers. A total of 175 patients underwent POCE assessments which were evaluated using Kappa statistics (κ) together with their estimated standard error, p value, and 95% CI bounds. Each patient had a mean of 3.3 ± 1.1 (±SD) assessments performed. Identical or nearly identical agreement between previously untrained primary providers and expert readers was evident for the diagnosis of tricuspid regurgitation, mitral regurgitation, pericardial effusion, and volume status. These agreements were strongest in apical long axis (κ=1, p < 0.001) and parasternal long and short axis views (κ > =0.82 p < 0.001), though agreement remained robust in apical 4-chamber views (κ ≥ 0.76). The agreements in LVEF assessment were identical in the apical long axis view (κ=1, p < 0.001) and robust in the remaining 3 views (κ > =0.66, p < 0.001). The assessments of aortic stenosis (parasternal/long, κ=0.42, and parasternal/short, κ=0.47, both p < 0.001) were weak in their agreement. Compared to expert echocardiography readers, the untrained providers' use of POCE for VHD shows high user adoptability and diagnostic accuracies in the primary care setting.

Ultrasonographic study of the right coronary artery in performance horses

Historically, echocardiography has focused on the assessment of cardiac dimensions and índices of cardiac function. However, when referred to ultrasonographic coronary arteries characterisation in the horse, information is scarce. The purpose of this study was to describe the right coronary artery in both long and short axis and to analyse its variability between horses with different levels of performance. Sixty healthy horses were included in the study. The animals were eventing horses at different levels of performance and were allocated into two groups according to their athletic level. The internal lumen diameter and the area of the right coronary artery (RCA) were measured in the right parasternal long and short axis views in the 3rd and 4th intercostal space respectively, during systole and diastole. The results were compared between groups using the analysis of variance (ANOVA) and Student's t-test. The correlation between the physiological parameters and the RCA was assessed using the Pearson correlation coefficient. Statistically significant differences were found when the RCA internal diameter was assessed between groups in both short and long axis. There were no statistically significant differences intra-group when short and long axis measurements were compared between each other. A positive correlation was observed between RCA and age, height, left atrium diameter, aortic valve diameter, sinus of Valsalva diameter, and aorta diameter. In conclusion, the level of training might affect the ultrasound measurement of the RCA in sport horses. Non-invasive echocardiography can be used to consistently assess the size of the right coronary artery in athletic horses in both short and long axis.

Long-Term Electrocardiographic and Echocardiographic Progression of Arrhythmogenic Right Ventricular Cardiomyopathy and Their Correlation With Ventricular Tachyarrhythmias.

Prior studies of structural and electrocardiographic changes in arrhythmogenic right ventricular (RV) cardiomyopathy and their role in predicting ventricular arrhythmias (ventricular tachycardia) have shown conflicting results. We reviewed 405 ECGs, 315 transthoracic echocardiographies, and 441 implantable cardioverter defibrillator interrogations in 64 arrhythmogenic RV cardiomyopathy patients (56% men, mean age [SD], 44.2 [14.6] years) over a mean follow-up of 10 (range, 2.3-19) years. Generalized estimating equations were used to identify the association between ECG abnormalities, clinical variables, and transthoracic echocardiographic measurements (>mild degree of tricuspid regurgitation, RV outflow tract diameter in parasternal long axis and short axis, RV end-diastolic area, fractional area change). There was a 4.65 (95% CI, 0.51%-8.8%) increase in RV end-diastolic area, a 3.75 (95% CI, 1.17%-6.34%) decrease in fractional area change, and 1.9 (95% CI, 1.3-2.8) higher odds (odds ratio) of RV wall motion abnormality with every 5-year increase in age after patients' first transthoracic echocardiography. >Mild tricuspid regurgitation was an independent predictor of RV enlargement and dysfunction (hazard ratio of >10% drop in fractional area change from baseline [95% CI], 3.51 [1.77-6.95] and hazard ratio of >10% increase in RV end-diastolic area from baseline [95% CI], 4.90 [2.52-9.52]). Patients with implantable cardioverter defibrillator were more likely to develop >mild tricuspid regurgitation and larger structural and functional disease progression. More pronounced increase in RV end-diastolic area was translated into higher rates of any ventricular tachycardia. Inferior T-wave inversions and sum of R waves (mm) in V1 to V3 were predictors of RV enlargement and dysfunction with the former also predicting risk of any ventricular tachycardia. Arrhythmogenic RV cardiomyopathy is a progressive disease. Tricuspid regurgitation is an independent predictor of structural disease progression, which may be exacerbated by use of a transvenous implantable cardioverter defibrillator lead.

A Novel Two-Dimensional Echocardiography Method to Objectively Quantify Aortic Valve Calcium and Predict Aortic Stenosis Severity

Aortic valve calcium (AVC) is a strong predictor of aortic stenosis (AS) severity and is typically calculated by multidetector computed tomography (MDCT). We propose a novel method using pixel density quantification software to objectively quantify AVC by two-dimensional (2D) transthoracic echocardiography (TTE) and distinguish severe from non-severe AS. A total of 90 patients (mean age 76 ± 10 years, 75% male, mean AV gradient 32 ± 11 mmHg, peak AV velocity 3.6 ± 0.6 m/s, AV area (AVA) 1.0 ± 0.3 cm2, dimensionless index (DI) 0.27 ± 0.08) with suspected severe aortic stenosis undergoing 2D echocardiography were retrospectively evaluated. Parasternal short axis aortic valve views were used to calculate a gain-independent ratio between the average pixel density of the entire aortic valve in short axis at end diastole and the average pixel density of the aortic annulus in short axis (2D-AVC ratio). The 2D-AVC ratio was compared to echocardiographic hemodynamic parameters associated with AS, MDCT AVC quantification, and expert reader interpretation of AS severity based on echocardiographic AVC interpretation. The 2D-AVC ratio exhibited strong correlations with mean AV gradient (r=0.72, p < 0.001), peak AV velocity (r=0.74, p < 0.001), AVC quantified by MDCT (r=0.71, p <0.001) and excellent accuracy in distinguishing severe from non-severe AS (area under the curve=0.93). Conversely, expert reader interpretation of AS severity based on echocardiographic AVC was not significantly related to AV mean gradient (t=0.23, p=0.64), AVA (t=2.94, p=0.11), peak velocity (t=0.59, p=0.46), or DI (t=0.02, p=0.89). In conclusion, these data suggest that the 2D-AVC ratio may be a complementary method for AS severity adjudication that is readily quantifiable at time of TTE.

ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2-Evidence Base and Standardized Methods of Imaging.

ASNC/AHA/ASE/EANM/HFSA/ISA/SCMR/SNMMI Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis: Part 1 of 2-Evidence Base and Standardized Methods of Imaging.

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

BackgroundIn majority of studies on speckle tracking echocardiography (STE) the strain estimates are averaged over large areas of the left ventricle. This may impair the diagnostic capability of the STE in the case of e.g. local changes of the cardiac contractility. This work attempts to evaluate, how far one can reduce the averaging area, without sacrificing the estimation accuracy that could be important from the clinical point of view.MethodsSynthetic radio frequency (RF) data of a spheroidal left ventricular (LV) model were generated using FIELD II package and meshes obtained from finite element method (FEM) simulation. The apical two chamber (A2C) view and the mid parasternal short axis view (pSAXM) were simulated. The sector encompassed the entire cross-section (full view) of the LV model or its part (partial view). The wall segments obtained according to the American Heart Association (AHA17) were divided into subsegments of area decreasing down to 3 mm2. Longitudinal, circumferential and radial strain estimates, obtained using a hierarchical block-matching method, were averaged over these subsegments. Estimation accuracy was assessed using several error measures, making most use of the prediction of the maximal relative error of the strain estimate obtained using the FEM derived reference. Three limits of this predicted maximal error were studied, namely 16.7%, 33% and 66%. The smallest averaging area resulting in the strain estimation error below one of these limits was considered the smallest allowable averaging area (SAAA) of the strain estimation.ResultsIn all AHA17 segments, using the A2C projection, the SAAA ensuring maximal longitudinal strain estimates error below 33% was below 3 mm2, except for the segment no 17 where it was above 278 mm2. The SAAA ensuring maximal circumferential strain estimates error below 33% depended on the AHA17 segment position within the imaging sector and view type and ranged from below 3–287 mm2. The SAAA ensuring maximal radial strain estimates error below 33% obtained in the pSAXM projection was not less than 287 mm2. The SAAA values obtained using other maximal error limits differ from SAAA values observed for the 33% error limit only in limited number of cases. SAAA decreased when using maximal error limit equal to 66% in these cases. The use of the partial view (narrow sector) resulted in a decrease of the SAAA.ConclusionsThe SAAA varies strongly between strain components. In a vast part of the LV model wall in the A2C view the longitudinal strain could be estimated using SAAA below 3 mm2, which is smaller than the averaging area currently used in clinic, thus with a higher resolution. The SAAA of the circumferential strain estimation strongly depends on the position of the region of interest and the parameters of the acquisition. The SAAA of the radial strain estimation takes the highest values. The use of a narrow sector could increase diagnostic capabilities of 2D STE.

Focused ultrasound in out-of-hospital cardiac arrest by advanced paramedics

Background: This study describes and evaluates advanced paramedic practitioner (APP) use of focused cardiac ultrasound (FoCUS) in out-of-hospital cardiac arrest (OHCA), and relates ultrasound findings with decisions to terminate resuscitation. The authors report characteristics of patients who do/do not undergo a FoCUS examination by APPs, ultrasound probe positions used and whether FoCUS findings were associated with decisions to terminate resuscitation or to convey patients to an emergency department (ED) with ongoing resuscitation. Method: A retrospective, observational cohort study of all adult medical OHCA patients attended by APPs in Greater London during 2018 was carried out using data from EMS and APP databases. Results: Twenty-eight APPs attended 1444 OHCA patients in 2018, of whom 744 underwent FoCUS. The subcostal probe position was used most frequently (74%), followed by the parasternal long axis (19%), with significantly smaller use of the parasternal short axis and apical windows. Absence of spontaneous cardiac motion (SCM) was associated with resuscitation being terminated (333 out of 391; 85%) and the presence of SCM was associated with conveyance to the emergency department (213 out of 264 patients; 80%). All decisions to terminate resuscitation were within the APP scope of practice. Conclusion: The authors believe this is the largest prehospital study involving FoCUS in OHCA. An association between FoCUS findings and decisions made to either convey patients to hospital or terminate resuscitation was found. The SC window was most used and ROLE decisions were deemed to be in accordance with local guidance and practice.

Focused ultrasound in out-of-hospital cardiac arrest by advanced paramedics

Background: This study describes and evaluates advanced paramedic practitioner (APP) use of focused cardiac ultrasound (FoCUS) in out-of-hospital cardiac arrest (OHCA), and relates ultrasound findings with decisions to terminate resuscitation. The authors report characteristics of patients who do/do not undergo a FoCUS examination by APPs, ultrasound probe positions used and whether FoCUS findings were associated with decisions to terminate resuscitation or to convey patients to an emergency department (ED) with ongoing resuscitation. Method: A retrospective, observational cohort study of all adult medical OHCA patients attended by APPs in Greater London during 2018 was carried out using data from emergency medical services (EMS) and APP databases. Results: Twenty-eight APPs attended 1444 OHCA patients in 2018, of whom 744 underwent FoCUS. The subcostal probe position was used most frequently (74%), followed by the parasternal long axis (19%), with significantly smaller use of the parasternal short axis and apical windows. Absence of spontaneous cardiac motion (SCM) was associated with resuscitation being terminated (333 out of 391; 85%) and the presence of SCM was associated with conveyance to the emergency department (213 out of 264 patients; 80%). All decisions to terminate resuscitation were within the APP scope of practice. Conclusion: The authors believe this is the largest prehospital study involving FoCUS in OHCA. An association between FoCUS findings and decisions made to either convey patients to hospital or terminate resuscitation was found. The SC window was most used and ROLE decisions were deemed to be in accordance with local guidance and practice.

Tricuspid valve in congenital heart disease: multimodality imaging and electrophysiological considerations.

The tricuspid valve (TV) has been neglected for many years. Only recently, new studies demonstrated the prognostic role of the tricuspid valve lesions. In addition to that, new interventional approaches offer the possibility to noninvasively treat tricuspid valve disease. In this review, our aim was to summarize the role of different imaging techniques in the assessment of tricuspid valve with particular regards to congenital heart diseases. Finally, we analyze the importance of the TV and its adjacent regions from an electrophysiological point of view, both in structurally normal hearts and in congenital heart diseases. The most relevant transthoracic echocardiography (TTE) views to visualize the TV are the "modified" parasternal long axis, the apical views and subcostal projections, such as right oblique or left oblique views. However, simultaneous visualization of the three leaflets is possible only with three-dimensional TTE or, sometimes, in parasternal short axis and subcostal short axis views in children. 3D echocardiography is promising in this field. Indeed, its unique projections, such as en-face views from the right ventricular and atrial perspectives, are able to define the spatial relationship of the tricuspid leaflets with the surrounding structures. Moreover, multimodality imaging assessment has been recently proposed for the diagnostic assessment of the TV, especially before percutaneous intervention. Cardiac computed tomography provides valuable anatomic spatial information of the TV apparatus. Cardiac magnetic resonance is able to provide, noninvasively, detailed morphological and functional information of the valve.

Analysis of left ventricular rotational deformation by 2D speckle tracking echocardiography: a feasibility study in athletes

2D speckle tracking echocardiography (2DSTE) is established to analyse left ventricular (LV) longitudinal function. The analysis of LV rotational deformation is challenging and requires standardization of image acquisition as well as postprocessing analysis. The aim of this study was to test the feasibility to analyse LV rotational deformation using 2DSTE by introducing a novel algorithm for the detection of artefacts. The study was performed in 20 healthy subjects serving as a control group and in 53 competitive sportsmen. Circumferential, radial strain (CS, RS) and LV rotation were analysed by 2DSTE in parasternal short axis views. The stepwise algorithm to exclude potential artefacts starts with the visual estimation of the image quality with respect to complete visualization of all myocardial segments during the entire cardiac cycle followed by the exclusion of data sets in participants with conduction abnormalities. The next step is the optimization of tracking areas and a cross-check of implausible strain waveforms in multiple acquired comparable cineloops. The last step is the exclusion of strain curves with persisting implausible waveforms if standardization failures and incorrect LV wall tracking are fixed. Plausible physiological strain curves were observed in 89% (n = 65/73) of all subjects. In controls all implausible waveforms could be verified as artefacts. The algorithm was applied in 53 professional athletes to test and confirm its feasibility. Abnormal CS waveforms were documented in 25 athletes, verified as artefacts due to tracking failures in 22 athletes and due to incorrect image acquisition in 3 athletes. CS artefacts were mostly located in the basal posterior and lateral LV segments. (endocardial: 6%, n = 4/70; p < 0.05) and basal posterior (endocardial: 8%, n = 5/70; p < 0.05) segments were highly susceptible to artefacts. 2DSTE of parasternal short axis views to analyse circumferential and radial deformation as well as LV rotation is feasible in athletes. The proposed algorithm helps to avoid artefacts and might contribute to standardization of this technique. 2DSTE might provide an interesting diagnostic tool for the detection of viral myocarditis, e.g. in athletes.