Mitral annular electrogram morphology - a balanced signal does not identify the anatomical annulus

Breaking the Mold: Lithotripsy for Mitral Annular Calcification.

Septal myectomy is a well-established surgical intervention for patients with hypertrophic obstructive cardiomyopathy (HOCM). However, mitral annulus dynamics in HOCM patients and the procedure's impact on them are not fully understood. This study aimed to evaluate the mitral valve annulus's dynamics and the effect of septal myectomy on its geometry and function using three-dimensional transesophageal echocardiography (3D TEE) in HOCM patients. A single-site, prospective observational study was conducted at a tertiary-level hospital; 26 patients with HOCM who underwent septal myectomy were included. Intraoperative 3D TEE was performed before and after surgery to assess mitral annular dimensions, area, and motion. Clinical outcomes, including New York Heart Association (NYHA) functional class and left ventricular outflow tract (LVOT) gradient, were also evaluated. Preoperative and postoperative transesophageal images were analyzed offline to measure mitral annular dynamics across the cardiac cycle using dedicated software and Doppler-derived pressure gradients. Throughout the four phases of the cardiac cycle (late diastole, early systole, mid-systole, and late systole), there were no significant dynamic changes in mitral annulus dimensions, specifically, the anteroposterior (AP) diameter (p = 0.286), anterolateral-posteromedial (AL-PM) diameter (p = 0.922), sphericity index (p = 0.311), inter-trigonal diameter (p = 0.982), intercommissural diameter (p = 0.999), 3D saddle-shaped annulus area (p = 0.714), 3D saddle-shaped annulus perimeter (p = 0.754), annulus height (p = 0.981), nonplanar angle (p = 0.902), aorto-mitral angle (p = 0.949), and saddling (p = 0.231). Immediately after septal myectomy, despite significant LVOT gradient reduction (88.4±45.6mmHg preoperative vs. 9.3±4.7mmHg postoperative; p<0.001), no significant improvements were detected in mitral annular parameters (p>0.05 for all parameters). 3D TEE offers critical insights into the dynamics of the mitral valve annulus across various phases of the cardiac cycle. In patients with HOCM, the mitral valve annulus exhibits reduced dynamic motion, with a notable loss of normal systolic AP contraction and saddling. Immediate postoperative assessments did not demonstrate significant improvements in mitral annulus dynamics. Therefore, further longitudinal studies are necessary to assess long-term changes in mitral annulus dynamics due to LV remodeling following septal myectomy procedures.

To develop a method for reducing mitral regurgitation in dogs by positioning and tightening a circumferential suture around the mitral valve annulus. Description of clinical cases. 15 dogs with spontaneous mitral valve disease, annular dilation, and refractory congestive heart failure treated between 1962 and 1994. A composite suture material was constructed using braided Teflon-impregnated polyester sternotomy suture, barium sulfate thread, and Silastic tubing. Through a left lateral thoracotomy, the suture was positioned around the mitral annulus by passing it through the coronary sinus, right atrium, and underneath the left coronary arteries before tightening it. Six dogs died during surgery because of hemorrhage from the left atrium, coronary sinus, or left coronary artery. Three dogs died postoperatively because of coronary artery compression by the suture. Satisfactory suture placement was achieved in six dogs, three of which were long-term survivors (6 to 26 months) before they were euthanatized for noncardiac reasons. Reduction of mitral annulus diameter with a circumferential purse-string suture does not require cardiopulmonary bypass. The surgery is technically difficult, and detailed knowledge of coronary artery anatomy is required. The current suture design is inexpensive, radiopaque, and biocompatible; no special instruments are required for placement. Mitral regurgitation is the most common cardiovascular disorder in dogs and the most common cause of congestive heart failure. Annular dilation occurs as a consequence of mitral regurgitation. Placement and tightening of a circumferential suture around the mitral annulus reduces the degree of mitral regurgitation.

To evaluate the narrowing of the left ventricular outflow tract (LVOT) during systole caused by a rigid mitral prosthesis, the geometric relationship between the prosthesis (or the mitral annulus) and the left ventricular base (LVB) was studied in five patients with mechanical mitral valve prostheses and eight normal subjects. The images of the mitral valve annulus (MVA) and the LVOT orifice reconstructed in three dimensions were projected on the plane of the LV base. Calculating the areas of these projected images (i.e., those for MVA [Sm], LVOT orifice [So], the LVB [Sb; Sb = Sm + So]), the MVA-LVB ratio (Sm/Sb) was determined. In the normal subject, the MVA-LVB ratio was nearly constant during systole (59 +/- 5% at 0 msec and 62 +/- 7% at 300 msec, respectively), whereas in the patients with prostheses, the ratio increased from 61 +/- 4% (0 msec) to 69 +/- 4% (300 msec). The increase in MVA-LVB ratio reduces the proportionate share of LVOT orifice in relation to the total LVB. The ideal mitral valve prosthesis should be flexible at the annulus to attain good performance in LVB dynamics.

In this paper we present a three-dimensional computational fluid dynamics (CFD) framework of the left atrium (LA) and its pulmonary veins (PVs). The framework uses magnetic resonance imaging (MRI) to render the subject-specific atrial and venous geometries. The aim was first to investigate the diastolic flow field in an anatomically representative model of the LA and PVs. Second, to investigate the impact of different positions of the PVs on the intra-atrial flow and on the resulting velocity distribution at the mitral valve (MV) plane. Three 3D models with different venous entry locations were created for this purpose. In the model with anatomically based PV positions, the velocity profile at the MV plane showed qualitatively good agreement with the MRI flow measurements. When comparing the flow field in the three models, the results clearly illustrate that the PVs have a significant impact on the intra-atrial flow and the final velocity profile at the MV plane. Because the interpatient variability in PV number and branching patterns is large, the velocity profile at the MV plane should be considered as a subject-specific property. Therefore, we suggest that in order to obtain a physiological correct simulation of ventricular filling and MV opening dynamics, a subject-specific representation of the atrial and venous anatomies should be included in the simulation model.

Noninvasive assessment of diastolic dysfunction relies on multiple echocardiographic indicators, including measurements from both standard B-mode images and Doppler, obtained at various cardiac locations such as the mitral annulus, tricuspid annulus, left ventricle, and left atrium. The diagnostic process is complex and subject to interobserver variability, making accurate and rapid evaluation challenging. Automated semantic segmentation of key cardiac structures, such as the left atrium, left ventricle, and mitral valve annulus, offers a potential solution by capturing temporal changes throughout the cardiac cycle. This study aims to improve the accuracy of segmenting the left atrium, left ventricle, and mitral valve annulus in echocardiographic images and to leverage the resulting temporal segmentation features for more reliable identification of diastolic dysfunction. This study presents Diff-TransUNet, a novel segmentation model incorporating a noise-robust Differential Transformer module. Evaluations on private (1137 training images, 135 validation images, and 88 test images), CAMUS (1400 training images, 200 validation images, and 200 test images), and EchoNet-Dynamic (5000 training images, 2546 validation images, and 2528 test images) datasets demonstrate improved performance over state-of-the-art methods, assessed by Dice coefficient (Dice), Intersection-over-Union (IoU), and 95th percentile Hausdorff Distance (HD95) metrics. Statistical analysis was performed to compare Diff-TransUNet with baseline methods across evaluation metrics. To control for errors arising from multiple comparisons, p-values were adjusted using the Benjamini-Hochberg false discovery rate (FDR) correction. Statistical significance was assessed at a 95% confidence level. In addition to p-values, Cohen's d effect size was computed to quantify the practical significance of performance differences. The proposed Diff-TransUNet achieved a Dice of 87.49%, IoU of 79.07%, and HD95 of 1.48 on the private dataset. Compared with state-of-the-art models, Dice improved by 1.35%-4.30% (p<0.05, Cohen's d=0.32-0.90), IoU by 1.97%-5.67% (p<0.05, Cohen's d=0.37-1.03), and HD95 by 0.16-0.83 (p<0.05, Cohen's d=0.21-0.90). On the CAMUS dataset, the model achieved a Dice of 88.74%, IoU of 80.58%, and HD95 of 2.83, showing improvements of 1.07%-4.96% (p<0.05, Cohen's d=0.18-0.63) in Dice, 1.55%-6.89% (p<0.05, Cohen's d=0.19-0.71) in IoU, and 0.41-2.85 (p<0.05, Cohen's d=0.12-0.46) in HD95 compared to advanced models. On the EchoNet-Dynamic dataset, the model obtained a Dice of 92.25%, IoU of 85.87%, and HD95 of 1.65, outperforming other methods by 0.42%-2.00% (p<0.05, Cohen's d=0.10-0.40) in Dice, 0.69%-3.21% (p<0.05, Cohen's d=0.10-0.43) in IoU, and 0.21-1.12 (p<0.05, Cohen's d=0.09-0.34) in HD95. Furthermore, by extracting volumetric segmentation features, the proposed method achieved an accuracy of 88.95% (95 % CI 87.15% to 90.08%) in identifying diastolic dysfunction. The proposed Diff-TransUNet model achieves significant improvements in ultrasound segmentation. Features extracted from the left ventricle, left atrium, and mitral annulus segmented by Diff-TransUNet can be effectively used for the identification of diastolic dysfunction.

OBJECTIVES: The present study was designed to investigate the dimensions of mitral valve annulus in the presence of mitral regurgitation. METHOD: Fifty-four patients were examined. On transthoracic echocardiographic images, we performed linear measurements in the parasternal plane in order to define the size of the left ventricle, left atrium, and mitral valve annulus. We compared these findings with those obtained in 16 control subjects. RESULTS: Twenty-one patients with mild or moderate mitral regurgitation demonstrated no significant change of the mitral valve annulus compared with the control group (P > 0.05). Seventeen patients with severe mitral regurgitation (grade of 4) had a significant increase of the dimensions of the mitral valve annulus, left ventricle, and left atrium (P < 0.05). The etiology of mitral regurgitation was degenerative in 32 patients, rheumatic in 2 patients, and mitral valve prolapse in 4 patients. All patients had normal left ventricular systolic function. Thirty-one patients were in normal sinus rhythm, and seven were in atrial fibrillation. CONCLUSIONS: The measurement of the diameter of the mitral valve annulus is feasible with transthoracic echocardiography. In addition to the evaluation of mitral valve leaflets and subvalvular apparatus, the measurement of the mitral valve annulus is important in the evaluation of mitral regurgitation, as its enlargement is indicative for severe mitral regurgitation.

Objective To define the mechanical features of mitral annulus at various sites,and to investigate the specific mechanics characterization at different mitral annulus sites in evaluation consequences of left ventricular function by dual pulse-wave Doppler (DPW) technology.Methods The DPW spectrums were obtained at lateral and aboral interval,anterior and inferior and posterior mitral annular from 112 normal adults.The peak systolic velocity (Sm),peak early diastolic velocity (Em),peak late diastolic velocity (Am),the beginning time of the peak and the time to peak were measured,and E/A,Em/Am,E/Em,left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were computed.Results 1)Sm,Em,Am and Em/Am measured in the free wall annulus were significantly greater than measured in the interval annulus of mitral annular sites.However,E/Em was opposited (P ＜ 0.05).Sm of the posterior wall mitral annulus accelerated frist and experienced shortest duration in all the mitral annular sites (P ＜ 0.01).There were no significant differences of Em time parameters among different mitral annulus sites.Am of the beginning time and peak time in the free wall annulus were significantly longer than that in the interval annulus of anterior mitral annular sites.However,the acceleration time was opposited(P ＜0.05).2) Sm was correlated with LVEF and LVFS (r =0.243 and r =0.227,P ＜0.01) only at the posterior mitral annular site,Em/Am of anterior and posterior wall mitral annulus had the highest correlations with mitral orifice flow E/A(r =0.545 and 0.545 respectively,P ＜ 0.01).Conclusions There are significant differences among the mechanics patterns at different mitral annulus sites in normal adults.The mechanics characterization at different mitral annulus sites have different conclusions of left ventricular function. Key words: Echocardiography; Ventricular function,left; Mitral annulus; Dual pulse-wave Doppler

The study of systolic changes in both the inflow and outflow of the left ventricle after mitral repair elucidates the geometric characteristics after surgery. The study included eight normal subjects and six patients after mitral repair without a prosthesis. The left ventricular (LV) base, consisting of both mitral valve annulus (MVA) and left ventricular outflow tract (LVOT) orifice, was reconstructed from magnetic resonance images. The angle between the planes of the MVA and LV base (MB angle), and the proportionate share of the LVOT at the LV base were calculated. After mitral repair, both the MVA and LV base became almost normal in size, showing flexible change (i.e., contraction and dorsiflexion) in the MVA and contraction of the LV base in systole. Compared with the normal heart at 100 ms delay from the electrocardiogram R wave, the hearts of the patients at the same phase had a mean 1.05 cm2 larger LVOT orifice, resulting in a mean 8.0 degree larger MB angle. Furthermore, the LVOT orifice occupied a mean of 49.5% of the LV base (41.9% in normal subjects). We hypothesize that the higher MB angle at early systole may weaken the tension of the chordae of the anterior mitral leaflet.

Introduction Accurate measurement of the mitral valve (MV) annulus is important for echocardiographic assessment of left ventricular stroke volume and, ultimately, essential for evaluating valvular disease. Current echocardiographic guidelines recommend estimating cross-sectional area (CSA) using the apical 4-chamber (A4C) view [1]. However, these estimations rely on geometric assumptions that can introduce error [2,3]. Additionally, inherent interobserver variability in echocardiography poses further challenges to measurement reliability. Purpose This study aims to investigate the impact of MV geometric assumptions on CSA estimation and assess the robustness of these measurements in the context of interobserver variability, using annotations from a large cohort of experienced sonographers. Methods MV diameters were estimated from manual MV annulus delineations at end-diastole (ED) in A4C and apical 2-chamber (A2C) sequences on a cohort of 10 patients (median age: 72 y, IQR: 52-77; 70% male) by 35 experienced sonographers (mean expertise 5.3 ± 2.9 y). Ground truth delineations and ED frames were defined by a clinical committee of experts. CSA was calculated based on a circular assumption using A4C (CSA_4C) and A2C (CSA_2C) views, as well as an elliptical assumption integrating both of them (CSA_4C2C) (Figure 1). Agreement and consistency across CSA estimates were evaluated via Pearson’s correlation, linear regression and Bland-Altman analysis. Interobserver variability was quantified using the coefficient of variation. Results MV diameters in A2C were significantly larger than in A4C (mean difference 0.27 ± 0.69 cm; p = 0.03), in contrast with prior literature [2,4]. The poor correlation between these measures (R = 0.33) further underscores their inconsistency. Similarly, CSA_2C and CSA_4C were weakly correlated (R = 0.35) and poorly agreed (mean difference: -1.2 cm2; 95% LoA: -7.4 to 5.0 cm2), while CSA_4C2C provided intermediate values, as expected. These results revealed substantial discrepancies between geometric assumptions and confirmed the presence of a systematic bias when relying on single-view area estimations. Regarding interobserver variability in CSA estimations, CSA_4C showed the highest variability (38.0 ± 9.8%), while CSA_4C2C notably evidenced a reduced variability (29.5 ± 6.8%) (Figure 2). This reduction highlighted the added robustness of combining views, rather than relying on a single-plane measurement. Conclusion This study demonstrates that: (1) CSA estimates of the MV annulus are substantially influenced by geometric assumptions; and (2) the elliptical approach, incorporating both A4C and A2C views, enhances measurement consistency and substantially reduces interobserver variability while maintaining strong correlation with the traditional A4C assessment, preferred in clinical guidelines. Altogether supports the adoption of the elliptical approach for MV annular area quantification in echocardiography.Figure 1 Figure 2

Although monopolar radiofrequency (RF) catheter ablation is being used to interrupt left-sided accessory pathways in patients with tachyarrhythmia, little is known of the histologic effects from this method of treatment. RF ablation at the mitral valve (MV) annulus was performed in ten dogs to examine the histology of the lesion area. A custom 6 French ablation catheter with a 4 mm distal electrode was positioned beneath the MV adjacent to the annulus. Mean preablation atrial to ventricular electrogram ratio (A/V ratio) was 0.26 +/- 0.17. Thirty +/- 1 watts of RF power were applied for 53 +/- 13 seconds between the distal electrode and a large skin electrode. Nine dogs were sacrificed 6 weeks and one dog 2 days following ablation. Annular lesions were seen in eight of the ten dogs. Lesion volume was 136 +/- 41 mm3 and correlated with the A/V ratio (r2 = 0.74, P = 0.006). Lesions consisted of necrosis of the left ventricle with extension into the atrioventricular groove and left atrium. No injury to the coronary sinus or circumflex artery was observed. A small area of injury was noticed on the mitral leaflet in one dog. Monopolar RF ablation creates lesions at the MV annulus without injury to adjacent vascular structures.

A simplified method for determining regurgitant fraction by Doppler echocardiography in patients with aortic regurtitation

Introduction

Objective To study the relationship between ischemic mitral regurgitation and geometric angles of the mitral valve leaflets in patients with coronary artery disease and papillary muscle dysfunction by transesophageal echocardiography（TEE）, and to evaluate anatomy and pathophysiology mechanicm of the ischemic mitral regurgitation with left ventricular papillary muscle dysfunction. Methods A total of 84 subjects were enrolled in this study. All of the subjects were divided into group A （healthy volunteers constituted the control group, n = 40）,group B （chronic inferior or posterior myocardial infarction patients with papillary muscle dysfunction group, n = 44）, group C（patients from group B after mitral valvuloplasty surgery, n = 20）.The relationship between mitral regurgitation and geometric angles of the mitral valve leaflets and mitral annulus were studied by TEE. Results Geometric angle between the mitral valve leaflets and mitral annulus were significantly larger in group B,and geometric angles of the mitral valve leaflets and mitral annulus was positive correlated with degree of mitral regurgitation. Degree of mitral regurgitation significantly reduced in group C, no significant difference was found at the geometric angles of the mitral valve leaflets and mitral valve annular compared with group A. Conclusions The degree of mitral regurgitation were highly correlated with geometric angles of the mitral valve leaflets and mitral valve annular in patients with left ventricular papillary muscle dysfunction caused by coronary heart dlsease.Repair of the mitral valve leaflets surgery can significantly reduce geometric angles of the mitral valve leaflets and mitral valve annular,and reduce the degree of mitral regurgitation significantly. Key words: Echocardiography, transesophageal; Mitral valve insufficiency; Papillary muscledysfunction ; Geometric angles

Intraatrial insertion of a mitral prosthesis in a destroyed or calcified mitral annulus