Abstract Objectives This study sought to observe the relationship between left atrial (LA) strain and left ventricular diastolic function and determine whether LA strain could be used to detect ...diastolic dysfunction (DD) and classify its degree when present. Background The assessment of diastolic function is complex and multiparametric because most conventional parameters do not follow the progression of DD. Strain imaging is an emerging index of LA function, with recent data demonstrating that LA strain is diminished in diastolic heart failure. However, LA strain is not part of the standard assessment of diastolic function. We hypothesized that LA strain decreases with worsening DD in a stepwise fashion and could thus be useful in evaluating DD. Methods We performed a retrospective derivation and validation cohort study to derive and test LA strain thresholds for DD grades (0 to 3) in patients with preserved left ventricular ejection fraction (N = 229). Two-dimensional speckle tracking was used to measure peak LA strain, which was applied as a single parameter to classify DD. American Society of Echocardiography guidelines were used as the reference standard. Results In the derivation cohort (n = 90), peak LA strain was significantly different between DD groups, with gradual decreases seen with worsening DD. Receiver-operating characteristic analysis resulted in 3 distinct LA strain thresholds for categorization of DD grades, with good to excellent diagnostic utility (area under the curve: 0.86 to 0.91). In an independent validation group (n = 139) with a spectrum of diastolic function, 11 patients (8%) had indeterminate DD grades using standard criteria, whereas LA strain was measured in all patients and its cutoffs resulted in diagnostic accuracy up to 95%. Conclusions LA strain measurements are feasible and allow accurate categorization of DD, because unlike the traditional parameters, it changes progressively with severity of DD. LA strain may become a useful tool for diastolic assessment in future clinical practice.
Abstract Objectives The goal of this study was to test the feasibility and accuracy of an automated algorithm that simultaneously quantifies 3-dimensional (3D) transthoracic echocardiography ...(TTE)-derived left atrial (LA) and left ventricular (LV) volumes and left ventricular ejection fraction (LVEF). Conventional manual 3D TTE tracings and cardiac magnetic resonance (CMR) images were used as a reference for comparison. Background Cardiac chamber quantification from 3D TTE is superior to 2D TTE measurements. However, integration of 3D quantification into clinical practice has been limited by time-consuming workflow and the need for 3D expertise. A novel automated software was developed that provides LV and LA volumetric quantification from 3D TTE datasets that reflect real-life manual 3-dimensional echocardiography measurements and values comparable to CMR. Methods A total of 159 patients were studied in 2 separate protocols. In protocol 1, 94 patients underwent 3D TTE imaging (EPIQ, iE33, X5-1, Philips Healthcare, Andover, Massachusetts) covering the left atrium and left ventricle. LA and LV volumes and LVEF were obtained using the automated software (HeartModel, Philips Healthcare) with and without contour correction, and compared with the averaged manual 3D volumetric measurements from 3 readers. In protocol 2, automated measurements from 65 patients were compared with a CMR reference. The Pearson correlation coefficient, Bland-Altman analysis, and paired Student t tests were used to assess inter-technique agreement. Results Correlations between the automated and manual 3D TTE measurements were strong (r = 0.87 to 0.96). LVEF was underestimated and automated LV end-diastolic, LV end-systolic, and LA volumes were overestimated compared with manual measurements. Agreement between the automated analysis and CMR was also strong (r = 0.84 to 0.95). Test–retest variability was low. Conclusions Automated simultaneous quantification of LA and LV volumes and LVEF is feasible and requires minimal 3D software analysis training. The automated measurements are not only comparable to manual measurements but also to CMR. This technique is highly reproducible and timesaving, and it therefore promises to facilitate the integration of 3D TTE-based left-heart chamber quantification into clinical practice.
The rapid technological developments of the past decade and the changes in echocardiographic practice brought about by these developments have resulted in the need for updated recommendations to the ...previously published guidelines for cardiac chamber quantification, which was the goal of the joint writing group assembled by the American Society of Echocardiography and the European Association of Cardiovascular Imaging. This document provides updated normal values for all four cardiac chambers, including three-dimensional echocardiography and myocardial deformation, when possible, on the basis of considerably larger numbers of normal subjects, compiled from multiple databases. In addition, this document attempts to eliminate several minor discrepancies that existed between previously published guidelines.
Echocardiographic quantification of left ventricular (LV) ejection fraction (EF) relies on either manual or automated identification of endocardial boundaries followed by model-based calculation of ...end-systolic and end-diastolic LV volumes. Recent developments in artificial intelligence resulted in computer algorithms that allow near automated detection of endocardial boundaries and measurement of LV volumes and function. However, boundary identification is still prone to errors limiting accuracy in certain patients. We hypothesized that a fully automated machine learning algorithm could circumvent border detection and instead would estimate the degree of ventricular contraction, similar to a human expert trained on tens of thousands of images.
Machine learning algorithm was developed and trained to automatically estimate LVEF on a database of >50 000 echocardiographic studies, including multiple apical 2- and 4-chamber views (AutoEF, BayLabs). Testing was performed on an independent group of 99 patients, whose automated EF values were compared with reference values obtained by averaging measurements by 3 experts using conventional volume-based technique. Inter-technique agreement was assessed using linear regression and Bland-Altman analysis. Consistency was assessed by mean absolute deviation among automated estimates from different combinations of apical views. Finally, sensitivity and specificity of detecting of EF ≤35% were calculated. These metrics were compared side-by-side against the same reference standard to those obtained from conventional EF measurements by clinical readers.
Automated estimation of LVEF was feasible in all 99 patients. AutoEF values showed high consistency (mean absolute deviation =2.9%) and excellent agreement with the reference values:
=0.95, bias=1.0%, limits of agreement =±11.8%, with sensitivity 0.90 and specificity 0.92 for detection of EF ≤35%. This was similar to clinicians' measurements:
=0.94, bias=1.4%, limits of agreement =±13.4%, sensitivity 0.93, specificity 0.87.
Machine learning algorithm for volume-independent LVEF estimation is highly feasible and similar in accuracy to conventional volume-based measurements, when compared with reference values provided by an expert panel.
Echocardiographic assessment of the right ventricle is difficult because of its complex shape. Three-dimensional echocardiographic (3DE) imaging allows more accurate and reproducible analysis of the ...right ventricle than two-dimensional methodology. However, three-dimensional volumetric analysis has been hampered by difficulties obtaining consistently high-quality coronal views, required by the existing software packages. The aim of this study was to test a new approach for volumetric analysis without coronal views by using instead right ventricle-focused three-dimensional acquisition with multiple short-axis views extracted from the same data set.
Transthoracic 3DE and cardiovascular magnetic resonance (CMR) images were prospectively obtained on the same day in 147 patients with wide ranges of right ventricular (RV) size and function. RV volumes and ejection fraction were measured from 3DE images using the new software and compared with CMR reference values. Comparisons included linear regression and Bland-Altman analyses. Repeated measurements were performed to assess measurement variability.
Sixteen patients were excluded because of suboptimal image quality (89% feasibility). RV volumes and ejection fraction obtained with the new 3DE technique were in good agreement with CMR (end-diastolic volume, r = 0.95; end-systolic volume, r = 0.96; ejection fraction, r = 0.83). Biases were, respectively, -6 ± 11%, 0 ± 15%, and -7 ± 17% of the mean measured values. In a subset of patients with suboptimal 3DE images, the new analysis resulted in significantly improved accuracy against CMR and reproducibility, compared with previously used coronal view-based techniques. The time required for the 3DE analysis was approximately 4 min.
The new software is fast, reproducible, and accurate compared with CMR over a wide range of RV size and function. Because right ventricle-focused 3DE acquisition is feasible in most patients, this approach may be applicable to a broader population of patients who can benefit from RV volumetric assessment.
The His-SYNC pilot trial was the first randomized comparison between His bundle pacing in lieu of a left ventricular lead for cardiac resynchronization therapy (His-CRT) and biventricular pacing ...(BiV-CRT), but was limited by high rates of crossover.
To evaluate the results of the His-SYNC pilot trial utilizing treatment-received (TR) and per-protocol (PP) analyses.
The His-SYNC pilot was a multicenter, prospective, single-blinded, randomized, controlled trial comparing His-CRT vs BiV-CRT in patients meeting standard indications for CRT (eg, NYHA II-IV patients with QRS >120 ms). Crossovers were required based on prespecified criteria. The primary endpoints analyzed included improvement in QRS duration, left ventricular ejection fraction (LVEF), and freedom from cardiovascular (CV) hospitalization and mortality.
Among 41 patients enrolled (aged 64 ± 13 years, 38% female, LVEF 28%, QRS 168 ± 18 ms), 21 were randomized to His-CRT and 20 to BiV-CRT. Crossover occurred in 48% of His-CRT and 26% of BiV-CRT. The most common reason for crossover from His-CRT was inability to correct QRS owing to nonspecific intraventricular conduction delay (n = 5). Patients treated with His-CRT demonstrated greater QRS narrowing compared to BiV (125 ± 22 ms vs 164 ± 25 ms TR, P < .001;124 ± 19 ms vs 162 ± 24 ms PP, P < .001). A trend toward higher echocardiographic response was also observed (80 vs 57% TR, P = .14; 91% vs 54% PP, P = .078). No significant differences in CV hospitalization or mortality were observed.
Patients receiving His-CRT on-treatment demonstrated superior electrical resynchronization and a trend toward higher echocardiographic response than BiV-CRT. Larger prospective studies may be justifiable with refinements in patient selection and implantation techniques to minimize crossovers.
The ongoing refinements in 3-dimensional (3D) echocardiography technology continue to expand the scope of this imaging modality in clinical cardiology by offering new features that stem from the ...ability to image the heart in its complete dimensionality. Over the years, countless publications have described these benefits and tested new frontiers where 3D echocardiographic imaging seemed to offer promising ways to improve patients' care. These include improved techniques for chamber quantification and novel ways to visualize cardiac valves, including 3D printing, virtual reality, and holography. The aims of this review article are to focus on the most important developments in the field in the recent years, discuss the current utility of 3D echocardiography, and highlight several interesting future directions.
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