Endocardium Of Left Ventricle Research Articles

Dynamic-guided Spatiotemporal Attention for Echocardiography Video Segmentation.

Left ventricle (LV) endocardium segmentation in echocardiography video has received much attention as an important step in quantifying LV ejection fraction. Most existing methods are dedicated to exploiting temporal information on top of 2D convolutional networks. In addition to single appearance semantic learning, some research attempted to introduce motion cues through the optical flow estimation (OFE) task to enhance temporal consistency modeling. However, OFE in these methods is tightly coupled to LV endocardium segmentation, resulting in noisy inter-frame flow prediction, and post-optimization based on these flows accumulates errors. To address these drawbacks, we propose dynamic-guided spatiotemporal attention (DSA) for semi-supervised echocardiography video segmentation. We first fine-tune the off-the-shelf OFE network RAFT on echocardiography data to provide dynamic information. Taking inter-frame flows as additional input, we use a dual-encoder structure to extract motion and appearance features separately. Based on the connection between dynamic continuity and semantic consistency, we propose a bilateral feature calibration module to enhance both features. For temporal consistency modeling, the DSA is proposed to aggregate neighboring frame context using deformable attention that is realized by offsets grid attention. Dynamic information is introduced into DSA through a bilateral offset estimation module to effectively combine with appearance semantics and predict attention offsets, thereby guiding semantic-based spatiotemporal attention. We evaluated our method on two popular echocardiography datasets, CAMUS and EchoNet-Dynamic, and achieved state-of-the-art.

Visualization of Left Ventricular Endocardium Activation Time during Cardiac Conduction System Pacing

Introduction. Right ventricular myocardial pacing leads to asynchronous contraction of the left ventricle (LV) and can impair its contractility over time. Stimulation of the conduction system of the heart ensures physiological activation of the ventricles.
 The aim. To visualize the pattern of propagation of the electrical front on the activation map of the LV endocardium during conduction system pacing and during right ventricular myocardial pacing.
 Materials and methods. In two patients with the conduction system pacing, who were operated at the National Amosov Institute of Cardiovascular Surgery, invasive LV activation mapping was performed on various options of cardiac pacing using the EnSite Precision TM navigation system. One patient with complete atrioventricular block had nonselective His bundle pacing. The second patient had dilated cardiomyopathy and indications for cardiac resynchronization therapy and ablation of the atrioventricular junction due to chronic tachyform of atrial fibrillation. After an unsuccessful attempt to place LV lead in coronary sinus, a lead for left bundle branch pacing was implanted. Different activation maps of the LV endocardium were built in two patients with two types of cardiac pacing: right ventricular myocardial pacing and cardiac conduction system pacing.
 Results. The total LV endocardial activation time was significantly different in the two studied patients with different pacing options. In a patient with non-selective stimulation of His bundle, the total LV endocardial activation time was 43 ms (QRS width 126 ms, the interval from the stimulus to the peak of the R wave in lead V6 78 ms). After switching to right ventricular myocardial pacing with a decrease in the pacing amplitude, the total LV endocardial activation time prolonged to 90 ms (QRS width 165 ms, the interval from the stimulus to the peak of the R wave in lead V6 117 ms). In a patient with left bundle branch pacing, total LV endocardial activation time was 51 ms (QRS width 160 ms, the interval from the stimulus to the peak of the R wave in lead V6 66 ms). With switching exclusively to right ventricular pacing the total LV endocardial activation time prolonged to 93 ms (stimulated QRS width 180 ms). At the same time, the activation pattern of the LV endocardium was significantly different, since the right ventricular lead was located closer to the apex.
 Conclusions. Conduction system pacing provides rapid physiological LV activation and potentially avoids the negative consequences of asynchronous slow ventricular activation during right ventricular pacing.

Diastolic vortex ring derangements in ischemic cardiomyopathy left ventricles: a 4D Flow MRI study

Abstract Funding Acknowledgements Type of funding sources: Private hospital(s). Main funding source(s): This work was supported by IRCCS Policlinico San Donato, a Clinical Research Hospital partially funded by the Italian Ministry of Health. Introduction Blood flowing into the left ventricle (LV) forms a 3D vortex ring starting from the free margin of mitral valve leaflets and encompassing the inflow jet. Vortex ring formation is presumed to store part of the kinetic energy of the entering jet and help directing blood flow towards the aorta [1]. Changes in vortex formation are associated to altered endocardial wall motion and LV chamber remodeling, as in case of ischemic cardiomyopathy (ICM). 4D Flow MRI is currently the unique volumetric imaging technique to assess in vivo changes of diastolic vortex ring. Purpose To characterize changes in LV diastolic vortex ring and associated energetics in a cohort of ICM patients (n = 12) vs. controls (n = 12) with comparable age. Methods 4D Flow MRI data were acquired for ICM patients presenting with anterior myocardial infarction and in healthy controls. The diastolic vortex ring was assessed at peak E-wave and at peak A-wave through the λ2 method [2]. Geometrical features of the vortex ring, e.g., circularity index (CI) and vortex orientation (α), were extracted (Figure 1). Kinetic energy (KE), rate of viscous energy loss (EL), vorticity and volume were computed for each vortex ring core; the ratios with the respective quantities computed for the entire LV were derived. Results At peak E-wave, the vortex ring was less circular (p = 0.017) and formed a smaller α with the mitral valve plane (p = 0.024) in ICM patients as compared to controls. At peak A-wave, the vortex ring core remained less circular (p = 0.027) in ICM patients, while vortex orientation remained comparable between the two groups. KE ratio, EL ratio, vorticity ratio and volume ratio significantly decreased for ICM patients at both E-peak and A-peak (Table 1). Conclusions Though ICM is primarily addressed and investigated as a systolic dysfunction, diastolic function can be deranged too, as highlighted by altered diastolic vortex ring shape and energetics.

A new method incorporating deep learning with shape priors for left ventricular segmentation in myocardial perfusion SPECT images

Accurate segmentation of the left ventricle (LV) is crucial for evaluating myocardial perfusion SPECT (MPS) and assessing LV functions. In this study, a novel method combining deep learning with shape priors was developed and validated to extract the LV myocardium and automatically measure LV functional parameters. The method integrates a three-dimensional (3D) V-Net with a shape deformation module that incorporates shape priors generated by a dynamic programming (DP) algorithm to guide its output during training. A retrospective analysis was performed on an MPS dataset comprising 31 subjects without or with mild ischemia, 32 subjects with moderate ischemia, and 12 subjects with severe ischemia. Myocardial contours were manually annotated as the ground truth. A 5-fold stratified cross-validation was used to train and validate the models. The clinical performance was evaluated by measuring LV end-systolic volume (ESV), end-diastolic volume (EDV), left ventricular ejection fraction (LVEF), and scar burden from the extracted myocardial contours. There were excellent agreements between segmentation results by our proposed model and those from the ground truth, with a Dice similarity coefficient (DSC) of 0.9573 ± 0.0244, 0.9821 ± 0.0137, and 0.9903 ± 0.0041, as well as Hausdorff distances (HD) of 6.7529 ± 2.7334 mm, 7.2507 ± 3.1952 mm, and 7.6121 ± 3.0134 mm in extracting the LV endocardium, myocardium, and epicardium, respectively. Furthermore, the correlation coefficients between LVEF, ESV, EDV, stress scar burden, and rest scar burden measured from our model results and the ground truth were 0.92, 0.958, 0.952, 0.972, and 0.958, respectively. The proposed method achieved a high accuracy in extracting LV myocardial contours and assessing LV functions.

Cross-Domain Echocardiography Segmentation with Multi-Space Joint Adaptation.

The segmentation of the left ventricle endocardium (LVendo) and the left ventricle epicardium (LVepi) in echocardiography plays an important role in clinical diagnosis. Recently, deep neural networks have been the most commonly used approach for echocardiography segmentation. However, the performance of a well-trained segmentation network may degrade in unseen domain datasets due to the distribution shift of the data. Adaptation algorithms can improve the generalization of deep neural networks to different domains. In this paper, we present a multi-space adaptation-segmentation-joint framework, named MACS, for cross-domain echocardiography segmentation. It adopts a generative adversarial architecture; the generator fulfills the segmentation task and the multi-space discriminators align the two domains on both the feature space and output space. We evaluated the MACS method on two echocardiography datasets from different medical centers and vendors, the publicly available CAMUS dataset and our self-acquired dataset. The experimental results indicated that the MACS could handle unseen domain datasets well, without requirements for manual annotations, and improve the generalization performance by 2.2% in the Dice metric.

An approach to help differentiate postinfarct scar from borderzone tissue using Ripple Mapping during ventricular tachycardia ablation.

Ventricular scar is traditionally highlighted on a bipolar voltage (BiVolt) map in areas of myocardium <0.50 mV. We describe an alternative approach using Ripple Mapping (RM) superimposed onto a BiVolt map to differentiate postinfarct scar from conducting borderzone (BZ) during ventricular tachycardia(VT) ablation. Fifteen consecutive patients (left ventricular ejection fraction 30 ± 7%) underwent endocardial left ventricle pentaray mapping (median 5148 points) and ablation targeting areas of late Ripple activation. BiVolt maps were studied offline at initial voltage of 0.50-0.50 mV to binarize the color display (red and purple). RMs were superimposed, and the BiVolt limits were sequentially reduced until only areas devoid of Ripple bars appeared red, defined as RM-scar. The surrounding area supporting conducting Ripple wavefronts in tissue <0.50 mV defined the RM-BZ. RM-scar was significantly smaller than the traditional 0.50 mV cutoff (median 4% vs. 12% shell area, p < .001). 65 ± 16% of tissue <0.50 mV supported Ripple activation within the RM-BZ. The mean BiVolt threshold that differentiated RM-scar from BZ tissue was 0.22 ± 0.07 mV, though this ranged widely (from 0.12 to 0.35 mV). In this study, septal infarcts (7/15) were associated with more rapid VTs (282 vs. 347 ms, p = .001), and had a greater proportion of RM-BZ to RM-scar (median ratio 3.2 vs. 1.2, p = .013) with faster RM-BZ conduction speed (0.72 vs. 0.34 m/s, p = .001). Conversely, scars that supported hemodynamically stable sustained VT (6/15) were slower (367 ± 38 ms), had a smaller proportion of RM-BZ to RM-scar (median ratio 1.2 vs. 3.2, p = .059), and slower RM-BZ conduction speed (0.36 vs. 0.63 m/s, p = .036). RM guided ablation collocated within 66 ± 20% of RM-BZ, most concentrated around the RM-scar perimeter, with significant VT reduction (median 4.0 episodes preablation vs. 0 post, p < .001) at 11 ± 6 months follow-up. Postinfarct scars appear significantly smaller than traditional 0.50 mV cut-offs suggest, with voltage thresholds unique to each patient.

Endocardial fibroelastosis causing sudden death in an infant: Autopsy case report of an unusual lesion.

Endocardial fibroelastosis is characterized by proliferation of both elastic and collagenous fibers within the endocardium, causing diffuse or localized thickening. A four-and-a-half-month-old baby was admitted to a local hospital, with a history of seizures for one day. Baby developed features of heart failure and died within one week after admission. At the post-mortem examination, heart was found to be enlarged with dilated ventricles. The endocardium of left ventricle was markedly thickened with a whitish appearance. Histopathology showed a thick layer of collagenous fibrous tissue in the endocardium, which was confirmed by Masson trichrome stain. The cause of death was offered as dilated cardiomyopathy due to endocardial fibroelastosis. The underlying mechanisms of myocardial fibrosis remain unclear. It is hypothesized that genetic, infectious, inflammatory, and nutritional processes are involved in this condition. This case highlights the importance of gross specimen examination and special staining methods to support histopathology after postmortem examination, for ascertaining the cause of death.

Terminal end of retro-aortic root branch: An unrecognized origin for "proximal left anterior fascicle" premature ventricular complexes with narrow QRS duration.

Premature ventricular complexes (PVCs) with narrow QRS duration, inferior frontal plane QRS axis, and right bundle branch block (RBBB) pattern generally originate from the proximal segment of the left anterior fascicle (LAF). The purpose of this study was to investigate the exact origin of this category of PVCs. Twenty-two patients with assumed proximal LAF-PVCs were enrolled in the study. Detailed mapping of fascicular potentials (FPs) was performed during sinus rhythm (SR) and PVCs. During SR, a cluster of FPs could be found at the most superior portion of the left ventricle (LV). These FPs represented the terminal end of a discrete branch of the left fascicular system, which we named the "retro-aortic root branch" (RARB). The shortest distance between the proximal LAF and the terminal end of the RARB was 13.5 ± 4.2 mm. The earliest activation site (EAS) of PVCs in all patients were confirmed at the terminal end of the RARB, where the FP-V interval was 35.1 ± 4.3 ms during PVCs. The shortest distance from the right coronary cusp (RCC) to the EAS was 5.3 ± 3.5 mm. PVCs could be eliminated by ablation from the RCC in 45.5% (10/22) cases, in the remaining cases, ablation at the EAS in the LV endocardium successfully abolished PVCs. The terminal end of the retro-aortic root branch was the actual origin site for PVCs with inferior frontal plane axis, RBBB pattern and narrow QRS duration. Ablation in the RCC or at the EAS in the LV could both eliminate PVCs safely with high efficacy.

Left Ventricle Segmentation in Cardiac MR Images via an Improved ResUnet.

Cardiovascular diseases are reported as the leading cause of death around the world. Automatic segmentation of the left ventricle (LV) from magnetic resonance (MR) images is essential for an early diagnosis. An enhanced ResUnet is proposed in this paper to improve the performance of extracting LV endocardium and epicardium from MR images, improving the accuracy of the model by introducing a medium skip connection for the contracting path and a short skip connection for the residual unit. Also, a depth-wise separable convolution replaces the typical convolution operation to improve training efficiency. In the MICCAI 2009 LV segmentation challenge test dataset, the percentages of “good” contours, dice metric, and average perpendicular distance of endocardium (epicardium) are 99.12% ± 2.29%(100% ± 0%), 0.93 ± 0.02 (0.96 ± 0.01), and 1.60 ± 0.42 mm (1.37 ± 0.23 mm), respectively. Experimental results demonstrate that the proposed model obtains promising performance and outperforms state-of-the-art methods. By incorporating these various skip connections, the segmentation accuracy of the model is significantly improved, while the depth-wise separable convolution also improves the model efficiency.

Anatomical variations in coronary venous drainage: challenges and solutions in delivering cardiac resynchronisation therapy

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac resynchronisation therapy (CRT) is the cornerstone of heart failure management. Delivery of a left ventricular lead can occur in a small proportion of patients undermining the benefits of this treatment. Abnormal coronary venous anatomy is a contributing factor to this failure. Although epicardial lead placement is available, this patient cohort requiring CRT is subject to higher peri-operative morbidity and mortality than the general population; a transvenous approach is preferable. Purpose To investigate the abnormalities of the coronary venous system in candidates for cardiac resynchronization therapy (CRT) and describe methods for circumventing the resulting difficulties. Methods From 4 implanting institutes, data of all CRT implants between October 2008-October 2020 were screened for abnormal cardiac venous anatomy, defined as an anatomical variation not conforming to the accepted ‘normal’ anatomy. Patient demographics, procedural detail and subsequent left ventricle (LV) lead pacing indices were collected. Results From a total of 3548 CRT implants, 15 (0.42%) patients (80% male) of 72.2±10.6 years in age with a LV ejection fraction of 34±10.3% were identified to have had an abnormal cardiac venous anatomy over the study period. There were 13 cases of persistent left side superior vena cava (pLSVC), 5 of which had coronary sinus ostium atresia (CSOA) including 2 with an ‘unroofed’ coronary sinus (CS); 1 patient had a unique anomalous origin of the CS and 1 patient had an isolated CSOA. In total 14 patients (60% repeat attempt) had successful percutaneous implant under general anaesthesia (46.7%) via the cephalic vein (59.1%), using the femoral approach (53.3%) for levophase venography and/or pull-through, including 1 case of endocardial LV implant. Pacing follow-up over 37.64±37.6 months demonstrated LV lead threshold between 0.62-2.9 volts (pulsewidth 0.4-1.5 milliseconds) in all cases; 5 patients died within 2.92±1.6 years of successful implant. Conclusion CRT devices can be implanted percutaneously even in the presence of substantial abnormalities of coronary venous anatomy. Alternative routes of venous access may be required.

P117 INCIDENTAL FINDING OF A PAPILLARY FIBROELASTOMA WITH UNCOMMON LOCATION: CASE REPORT

Abstract A 64–year old man with no cardiological history came to our laboratory to perform a transthoracic echocardiogram because of increased blood pressure. Patient was asymptomatic. Echocardiogram revealed the presence of a small mass attached to the proximal part of the interventricular septum (IVS) (Fig. 1), characterized by high mobility within the left ventricular outflow tract (LVOT). Transesophageal echocardiogram confirmed the presence of a 8 mm pedunculated mass with implant base on IVS, 2 cm below the aortic valve and oscillating in LVOT (Fig. 2). The high risk of peripheral embolization led the Heart team to propose cardiac surgery. The operation was conducted through a J–ministernotomy on a fourth intercostal space, cannulation of ascending aorta and right atrium, transverse aortotomy and identification of the mass via the transaortic route. The appearance of the mass, glossy brown and with a gelatinous consistency, first appeared to be attributable to papillary fibroelastoma. The histological investigation (Fig. 3) confirmed the diagnosis. Postoperative course was regular and the patient was discharged on fifth postoperative day. Discussion Papillary fibroelastoma is the third most common primary cardiac tumour, after myxoma and lipoma, with an incidence of around 10%. In 90% of the cases the origin is from the valvular endocardium (the aortic and mitral valve surfaces are the most affected sites), while the origin from the endocardium of left ventricle, as in the case of our patient, is much more rare (less than 10% of cases). Atypical locations, in addition to IVS, are papillary muscles, tendinous chords and atrial endocardium. Although most patients are asymptomatic, consequences related to peripheral embolization can be very serious (neurological complications, acute coronary sindrome, peripheral ischaemia, pulmonary embolism). Mobility rather than size appears to be an indipendent predictor of death and non fatal embolization; for this reason, in the presence of mobile and pedunculated mass, surgical intervention is always reccomended. Surgical excision is associated with a low operative risk and the minimally invasive approach, as in our case, allows for a rapid recovery.

Anatomical variations in coronary venous drainage: Challenges and solutions in delivering cardiac resynchronization therapy.

To investigate the abnormalities of the coronary venous system in candidates for cardiac resynchronization therapy (CRT) and describe methods for circumventing the resulting difficulties. From four implanting institutes, data of all CRT implants between October 2008 and October 2020 were screened for abnormal cardiac venous anatomy, defined as an anatomical variation not conforming to the accepted 'normal' anatomy. Patient demographics, procedural detail, and subsequent left ventricle (LV) lead pacing indices were collected. From a total of 3548 CRT implants, 15 (0.42%) patients (80% male) of 72.2 ± 10.6 years in age with an LV ejection fraction of 34 ± 10.3% were identified to have had an abnormal cardiac venous anatomy over the study period. There were 13 cases of persistent left side superior vena cava (pLSVC), five of which had coronary sinus ostium atresia (CSOA) including two with an "unroofed" coronary sinus (CS); one patient had a unique anomalous origin of the CS and one patient had an isolated CSOA. In total 14 patients (60% repeat attempt) had successful percutaneous implant under general anesthesia (46.7%) via the cephalic vein (59.1%), using the femoral approach (53.3%) for levophase venography and/or pull-through, including one case of endocardial LV implant. Pacing follow-up over 37.64 ± 37.6 months demonstrated LV lead threshold between 0.62 and 2.9 volts (pulsewidth 0.4-1.5 ms) in all cases; five patients died within 2.92 ± 1.6 years of a successful implant. CRT devices can be implanted percutaneously even in the presence of substantial abnormalities of coronary venous anatomy. Alternative routes of venous access may be required.

CA-534-01 PULSED FIELD ABLATION COMPARED TO RADIOFREQUENCY ABLATION OF LEFT VENTRICULAR MYOCARDIUM IN A SWINE INFARCT MODEL

There is limited data on use of pulsed field ablation (PFA) in the left ventricle (LV), particularly in the presence of myocardial scar To evaluate the lesion characteristics of PFA and radiofrequency energy (RFA) in healthy and infarcted LV myocardium 10 swine were included: 8 underwent 120min LAD balloon occlusion myocardial infarction and were survived for 6-8 weeks; 2 were healthy controls. PFA and standard RFA was delivered to the LV endocardium in healthy myocardium or scar identified with electroanatomic mapping. Bipolar, biphasic PFA was delivered at 1800 to 2000V for 2.5secs x 4 applications/site using 2 different catheters: linear quadripolar (LINEAR) or multi-spline 8-pole catheter (BASKET). Irrigated RF energy was delivered from 35W-50W to achieve >10 ohm impedance drop. Detailed histologic measurements of ablation depth were performed. In the PFA group, 21 lesions were delivered to healthy LV and 20 to scar, all without complications. There was no significant difference in histologic lesion depth in healthy myocardium or scar between LINEAR vs. BASKET PFA catheters (Figure A). In the RF group, 19 lesions were delivered to healthy LV and 8 to scar. Maximal lesion depth for PFA and RFA were similar in healthy tissue, however lesion depth was greater for PFA than RFA in scar (Figure B, 6.1±1.7 vs 3.8±1.7 mm; P=0.005). There was no vascular injury observed with PFA, however RFA led to adventitial edema and thrombosis. PFA allows rapid, safe and effective ablation of surviving islands of myocardium within infarcted LV substrate. Lesion depth in myocardial scar is greater for PFA than RFA. This technology holds promise for treating infarct-related ventricular tachycardia in humans.

Semi-supervised segmentation of echocardiography videos via noise-resilient spatiotemporal semantic calibration and fusion.

We present a novel model for left ventricle endocardium segmentation from echocardiography video, which is of great significance in clinical practice and yet a challenging task due to (1) the severe speckle noise in echocardiography videos, (2) the irregular motion of pathological heart, and (3) the limited training data caused by high annotation cost. The proposed model has three compelling characteristics. First, we propose a novel adaptive spatiotemporal semantic calibration method to align the feature maps of consecutive frames, where the spatiotemporal correspondences are figured out based on feature maps instead of pixels, thereby mitigating the adverse effects of speckle noise in the calibration. Second, we further learn the importance of each feature map of neighbouring frames to the current frame from the temporal perspective so as to distinctively rather than uniformly harness the temporal information to tackle the irregular and anisotropic motions. Third, we integrate these techniques into the mean teacher semi-supervised architecture to leverage a large amount of unlabeled data to improve the segmentation accuracy. We extensively evaluate the proposed method on two public echocardiography video datasets (EchoNet-Dynamic and CAMUS), where the average dice coefficient on the left ventricular endocardium segmentation achieves 92.87% and 93.79%, respectively. Comparisons with state-of-the-art methods also demonstrate the effectiveness of the proposed method by achieving a better segmentation performance with a faster speed.

Anatomical knowledge based level set segmentation of cardiac ventricles from MRI

This paper represents a novel level set framework for segmentation of cardiac left ventricle (LV) and right ventricle (RV) from magnetic resonance images based on anatomical structures of the heart. We first propose a level set approach to recover the endocardium and epicardium of LV by using a bi-layer level set (BILLS) formulation, in which the endocardium and epicardium are represented by the 0-level set and k-level set of a level set function. Furthermore, the recovery of LV endocardium and epicardium is achieved by a level set evolution process, called convexity preserving bi-layer level set (CP-BILLS). During the CP-BILLS evolution, the 0-level set and k-level set simultaneously evolve and move toward the true endocardium and epicardium under the guidance of image information and the impact of the convexity preserving mechanism as well. To eliminate the manual selection of the k-level, we develop an algorithm for automatic selection of an optimal k-level. As a result, the obtained endocardial and epicardial contours are convex and consistent with the anatomy of cardiac ventricles. For segmentation of the whole ventricle, we extend this method to the segmentation of RV and myocardium of both left and right ventricles by using a convex shape decomposition (CSD) structure of cardiac ventricles based on anatomical knowledge. Experimental results demonstrate promising performance of our method. Compared with some traditional methods, our method exhibits superior performance in terms of segmentation accuracy and algorithm stability. Our method is comparable with the state-of-the-art deep learning-based method in terms of segmentation accuracy and algorithm stability, but our method has no need for training and the manual segmentation of the training data.

Semi-automated left ventricular endocardial detection versus hand-tracing in the measurement of left ventricular volumes and ejection fraction in daily clinical practice

Abstract Background The common method of assessing left ventricle (LV) volumes and ejection fraction (EF) is hand-tracing Biplane Simpson method. Alternatively, ultrasound vendors offer different semi-automated LV endocardial border detection software with anatomical intelligence to assess LV volumes and EF. By using speckle-tracking technique, this software tracks the LV endocardium throughout the cardiac cycle and computes the LV volumes in every image frame using the disk summation method from which a volume-curve is generated, and the EF is calculated using the maximum and minimum volumes obtained. Data on the performance of this method in comparison with the hand-tracing Biplane Simpson method in daily clinical practice is scarce. Purpose To determine the accuracy of LV volumes and EF using semi-automated LV endocardial detection tracing, and to compare the reproducibility of this method with the hand-tracing Biplane Simpson method, among operators with varying level of experience in echocardiography. Methods This was a single center retrospective observational study, conducted in year 2020. 127 patients, aged &amp;gt;18 years, who underwent clinically indicated transthoracic echocardiography were recruited. The echocardiographic images were analyzed independently in a blinded fashion by 3 operators – a sonographer, a fellow-in-training and a cardiologist specialized in echocardiography. The LV volumes and EF were first measured using hand-tracing Biplane Simpson method, then repeated using semi-automated tracing at a different time and the operator were blinded to the initial hand-tracing measurements. Results The mean age of patients was 50±16 years, 35.4% were male, mean body surface area was 1.62±0.18m2, 92.1% were in sinus rhythm, and 61.4% had good acoustic window. Table 1 shows the LV end-diastolic volume (EDV), end-systolic volume (ESV) and EF, measured using different method, by the 3 operators. There were excellent correlation and agreement between semi-automated tracing measurements and hand-tracing measurements of LV EDV (r=0.985, LOA [mean ± 1.96 SD] 16.9 ml, ICC 0.991), ESV (r=0.990, LOA 12.7 ml, ICC 0.994) and EF (r=0.962, LOA 7.43%, ICC 0.967) by experienced cardiologist. The limit of agreement (LOA) between cardiologist and sonographer for semi-automated tracing measurement of LV EDV, ESV and EF were 29.13 ml, 19.74 ml and 9.25% respectively, which was comparable with that of hand-tracing measurement. The agreement between cardiologist and fellow-in-training for semi-automated tracing measurement of LV volumes and EF was slightly better than hand-tracing method, with a LOA of 25.60 ml, 17.48 ml and 7.08%, for EDV, ESV and EF respectively (Table 2). Conclusion In daily clinical practice, measurement of LV volumes and EF using semi-automated LV endocardial tracing method is accurate and demonstrates comparable reproducibility with hand-tracing Biplane Simpson method among operators with different level of experience in echocardiography. Funding Acknowledgement Type of funding sources: None.

Physiology and Practicality of Left Ventricular Septal Pacing.

Left ventricular septal pacing (LVSP) and left bundle branch pacing (LBBP) have been introduced to maintain or correct interventricular and intraventricular (dys)synchrony. LVSP is hypothesised to produce a fairly physiological sequence of activation, since in the left ventricle (LV) the working myocardium is activated first at the LV endocardium in the low septal and anterior free-wall regions. Animal studies as well as patient studies have demonstrated that LV function is maintained during LVSP at levels comparable to sinus rhythm with normal conduction. Left ventricular activation is more synchronous during LBBP than LVSP, but LBBP produces a higher level of intraventricular dyssynchrony compared to LVSP. While LVSP is fairly straightforward to perform, targeting the left bundle branch area may be more challenging. Long-term effects of LVSP and LBBP are yet to be determined. This review focuses on the physiology and practicality of LVSP and provides a guide for permanent LVSP implantation.

A novel approach for left ventricle segmentation in tagged MRI

Automatic left ventricle (LV) segmentation from tagged cardiac magnetic resonance imaging is significant for evaluating heart function and providing follow-up treatments in clinical medicine. However, due to the complicated cardiac structure and extra interference, it is challenging for traditional methods to delineate the LV automatically and get accurate results. Therefore, we proposed the automatic LV segmentation algorithm combined with deep learning and curriculum learning strategy. The key technologies are described as follows: firstly, local sine-wave modeling (SinMod) is practiced to track cardiac motion information, implement automatic heart location and obtain the region of interest. Secondly, U-Net is utilized as the basic model to segment the LV endocardium and epicardium. Additionally, a new curriculum learning training strategy is adopted to improve segmentation accuracy. Finally, comparative results demonstrate the superior performance of our approach to those resulting from traditional methods.

Deep learning based fully automatic segmentation of the left ventricular endocardium and epicardium from cardiac cine MRI.

The segmentation of cardiac medical images is a crucial step for calculating clinical indices such as wall thickness, ventricular volume, and ejection fraction. In this study, we introduce a method named LsUnet that combines multi-channel, fully convolutional neural network, and annular shape level-set methods for efficiently segmenting cardiac cine magnetic resonance (MR) images. In this method, the multi-channel deep learning algorithm is applied to train the segmentation task to extract the left ventricle (LV) endocardial and epicardial contours. Next, the segmentation contours from the multi-channel deep learning method are incorporated into a level-set formulation, which is dedicated explicitly to detecting annular shapes to assure the segmentation's accuracy and robustness. The proposed automatic approach was evaluated on 95 volumes (total 1,076 slices, ~80% as for training datasets, ~20% 2D as for testing datasets). This combined multi-channel deep learning and annular shape level-set segmentation method achieved high accuracy with average Dice values reaching 92.15% and 95.42% for LV endocardium and epicardium delineation, respectively, in comparison to the reference standard (the manual segmentation). A novel method for fully automatic segmentation of the LV endocardium and epicardium from different MRI datasets is presented. The proposed workflow is accurate and robust compared to the reference and other state-of-the-art methods.

Percutaneous transluminal septal myocardial ablation markedly reduces energy loss in hypertrophic obstructive cardiomyopathy: a four-dimensional flow magnetic resonance imaging study

Abstract Background Functional follow-up modalities of hypertrophic obstructive cardiomyopathy (HOCM) subjected to percutaneous transluminal septal myocardial ablation (PTSMA) are limited mainly to echocardiography and catheterization. Recent advancements in four-dimensional (4D) flow magnetic resonance imaging (MRI) have enabled us to assess patients from the perspective of fluid dynamics by visualising blood flow and calculating quantitative parameters such as wall shear stress and energy loss within cardiac chambers or blood vessels. Several reports have demonstrated that the intra-cardiac energy loss decreased along with improvement of cardiac function achieved by treatment of cardiac diseases. Whether changes in energy loss occur along with PTSMA in HOCM patients and the underlying mechanism remain unknown. Purpose This study sought to investigate the influence of PTSMA in patients with HOCM on energy loss in the left ventricle (LV) and aortic root measured by 4D flow MRI. Methods We retrospectively recruited HOCM patients who underwent PTSMA at a referral centre from May to November 2019. Patients who underwent 4D flow MRI both before and after PTSMA were included. We collected demographic and clinical data from electronic health records. MRI scans implemented two-dimensional phase-contrast imaging of the three-chamber plane with three-directional velocity, using a 1.5 T scanner. Furthermore, 4D blood flow analysis was performed on off-line saved data, using iTFlow version 1.9. We assessed energy loss in one cardiac cycle within the three-chamber plane of the LV and aortic root (area surrounded by the LV endocardium, sinotubular junction, and mitral annulus). Results This study finally included 12 patients, whose mean age was 66±12 years, and 5 (42%) of whom were men. The pressure gradient between the LV apex and ascending aorta was 81±32 mmHg before and 20±22 mmHg immediately after PTSMA (P&amp;lt;0.005, paired). Before PTSMA, 6 patients were in New York Heart Association functional class III and the other 6 in class II. However, after PTSMA, 10 patients improved to class I and 2 to class II. PTSMA reduced energy loss in one cardiac cycle within the three-chamber plane of the LV and aortic root, from 79±36 mJ/m to 55±19 mJ/m (P=0.001, paired). Conclusions PTSMA in patients with HOCM reduced energy loss within the LV and aortic root, indicating significant decrease with cardiac workload. Four-dimensional flow MRI of the three-chamber plane to assess energy loss within the LV and aortic root is a time-efficient and reproducible quantitative method to evaluate the effects of PTSMA. Given its non-invasive nature, it also enables to sequentially follow-up HOCM patients who underwent PTSMA. Periprocedural changes of energy loss Funding Acknowledgement Type of funding source: None