Atrial Chamber Research Articles

Left fouratrial heart. First clinical case

The left three-atrial heart (LTH) is a rare congenital abnormality where the left auricle (LA) is divided into two chambers with an additional membrane. This article describes for the first time a clinical case of congenital heart defect with four atrial chambers. A 41-old man was hospitalized for newly diagnosed paroxysmal atrial fibrillation. On transthoracic echocardiogram (EchoCG), LA was considerably enlarged and divided into two equal interconnected parts with a membrane. Additional examination with contrast-enhanced EchoCG and computed tomography revealed two membranes dividing the LA into three chambers. Prediction for the patient was beneficial since there were no other developmental abnormalities of the heart, and the LA transmembrane pressure gradient (PG) was small. Data of literature on the incidence and prognosis of LTH are provided.

All’s Not Well(ens) that Ends Well: Case Study of Significant Thebesian Veins Mimicking Wellens Syndrome

Thebeisan veins are microfistulous connections between a coronary arterial branch directly to a ventricular or atrial chamber. Extensive thebesian veins that empty into the left ventricle can cause typical chest pain symptoms, troponin elevation, and ischemic EKG changes from coronary steal leading to acute coronary syndrome in extreme cases. Literature review exposed a consistent pattern of EKG findings among patients with extensive thebesian veins involving all three major coronary arteries. We present a case study as an example of this rare anatomic finding of extensive thebesian veins draining into the left ventricle causing acute coronary syndrome in a symptomatic patient with elevated troponin and ischemic changes on EKG. This same EKG pattern that is present in our patient was discovered to be consistent among available case studies reviewed that had included an EKG tracing in their report. A newly proposed association between the ischemic changes on EKG due to extensive thebeisan veins and those of a severe proximal left anterior descending coronary artery stenotic lesion was discovered. The newly discovered consistency in the EKG pattern with acute coronary syndrome caused by extensive thebesian veins is the same pattern as that seen in Wellens Syndrome.

Hemodialysis patients with less extracellular water overload and smaller cardiac atrial chamber sizes are at greater risk of a fall in blood pressure during dialysis.

Intradialytic hypotension is the most common complication of hemodialysis (HD) treatments. Excessive ultrafiltration results in reduced cardiac preload. We aimed to determine whether a fall in systolic blood pressure during HD was greater in patients starting HD with (a) less overhydration measured by extracellular water (ECW) and (b) lower cardiac preload by cardiac magnetic resonance imaging (MRI). Pre-HD measurements of ECW and total body water (TBW) were performed using multifrequency bioimpedance (MFBIA). Cardiac chamber sizes and functions were determined by MRI. Twenty-six patients, 18 males (69.2%), 11 (42.3%) with diabetes, mean age 63.9 ± 15.9 years were studied. Systolic blood pressure (SBP) fell in 15 (57.7%) patients, and either did not change or increased in 9. There was no difference in demographics between groups. Patients with a fall in SBP had lower pre-HD ECW/TBW (0.400 ± 0.018 vs 0.418 ± 0.021), indexed right ventricular end-diastolic volume (81.2 ± 37.6 vs 100.8 ± 33.7 mL/m2 ), and indexed left atrial size (13.7 ± 3.9 vs 18.3 ± 5.0 mL/m2 ), all P < .05, respectively. There were univariate correlations between the change in SBP and pre-HD ECW/TBW for the trunk (r = .50, P = .009) and indexed left atrial volume (r = .54, P = .005). A fall in blood pressure occurred more commonly in patients starting HD with lower overhydration as measured by bioimpedance, and those with smaller cardiac chamber sizes. Patients with the lowest ECW/TBW and smallest cardiac chamber sizes had the greatest falls in SBP. This study reinforces the importance of determining physiological target weights and avoiding inappropriately low target weights for HD patients.

Gon4l/Udu regulates cardiomyocyte proliferation and maintenance of ventricular chamber identity during zebrafish development

Vertebrate heart development requires spatiotemporal regulation of gene expression to specify cardiomyocytes, increase the cardiomyocyte population through proliferation, and to establish and maintain atrial and ventricular cardiac chamber identities. The evolutionarily conserved chromatin factor Gon4-like (Gon4l), encoded by the zebrafish ugly duckling (udu) locus, has previously been implicated in cell proliferation, cell survival, and specification of mesoderm-derived tissues including blood and somites, but its role in heart formation has not been studied. Here we report two distinct roles of Gon4l/Udu in heart development: regulation of cell proliferation and maintenance of ventricular identity. We show that zygotic loss of udu expression causes a significant reduction in cardiomyocyte number at one day post fertilization that becomes exacerbated during later development. We present evidence that the cardiomyocyte deficiency in udu mutants results from reduced cell proliferation, unlike hematopoietic deficiencies attributed to TP53-dependent apoptosis. We also demonstrate that expression of the G1/S-phase cell cycle regulator, cyclin E2 (ccne2), is reduced in udu mutant hearts, and that the Gon4l protein associates with regulatory regions of the ccne2 gene during early embryogenesis. Furthermore, udu mutant hearts exhibit a decrease in the proportion of ventricular cardiomyocytes compared to atrial cardiomyocytes, concomitant with progressive reduction of nkx2.5 expression. We further demonstrate that udu and nkx2.5 interact to maintain the proportion of ventricular cardiomyocytes during development. However, we find that ectopic expression of nkx2.5 is not sufficient to restore ventricular chamber identity suggesting that Gon4l regulates cardiac chamber patterning via multiple pathways. Together, our findings define a novel role for zygotically-expressed Gon4l in coordinating cardiomyocyte proliferation and chamber identity maintenance during cardiac development.

Inferring Tunicate Relationships and the Evolution of the Tunicate Hox Cluster with the Genome of Corella inflata.

Tunicates, the closest living relatives of vertebrates, have served as a foundational model of early embryonic development for decades. Comparative studies of tunicate phylogeny and genome evolution provide a critical framework for analyzing chordate diversification and the emergence of vertebrates. Toward this goal, we sequenced the genome of Corella inflata (Ascidiacea, Phlebobranchia), so named for the capacity to brood self-fertilized embryos in a modified, “inflated” atrial chamber. Combining the new genome sequence for Co. inflata with publicly available tunicate data, we estimated a tunicate species phylogeny, reconstructed the ancestral Hox gene cluster at important nodes in the tunicate tree, and compared patterns of gene loss between Co. inflata and Ciona robusta, the prevailing tunicate model species. Our maximum-likelihood and Bayesian trees estimated from a concatenated 210-gene matrix were largely concordant and showed that Aplousobranchia was nested within a paraphyletic Phlebobranchia. We demonstrated that this relationship is not an artifact due to compositional heterogeneity, as had been suggested by previous studies. In addition, within Thaliacea, we recovered Doliolida as sister to the clade containing Salpida and Pyrosomatida. The Co. inflata genome provides increased resolution of the ancestral Hox clusters of key tunicate nodes, therefore expanding our understanding of the evolution of this cluster and its potential impact on tunicate morphological diversity. Our analyses of other gene families revealed that several cardiovascular associated genes (e.g., BMP10, SCL2A12, and PDE2a) absent from Ci. robusta, are present in Co. inflata. Taken together, our results help clarify tunicate relationships and the genomic content of key ancestral nodes within this phylogeny, providing critical insights into tunicate evolution.

Chronic Hemodynamic Overload of the Atria is an Important Factor for Shear Signaling Remodeling in Rat Hearts

Hemodynamic disturbances induced by hypertension, heart failure, and valve diseases lead atrial fibrillation. We have previously shown that shear stress induces proarrhythmic Ca2+ waves via connexin43 (Cx43) hemichannel opening, and that ATP release through the Cx43, in turn, activates P2Y1 receptors (P2Y1Rs) and P2X4 receptors (P2X4Rs) in rat atrial myocytes. To understand cellular mechanism for mechanically-induced atrial arrhythmia and role of shear signaling in this pathogenesis, we compared atrial shear signaling between sham-operated rats and the rats subjected to prolonged transverse aortic constriction (TAC). Atrial cell hypertrophy with higher fractional shortening and dilation of atrial chamber were observed at 5 weeks (wk) after TAC surgery. On 4-month (mon) after TAC surgery, more severe dilation in atrium with lower fractional shortening was detected. Whole-cell patch clamp studies revealed that shear-induced nonselective cation currents that are mediated by P2X4Rs (about 50%) and Cx43 (about 20%), were enhanced with hypertrophy, but they were no longer enhanced during atrial failure. Total Cx43 proteins and phosphorylated Cx43 at its ser-368 residue were gradually increased by TAC, which was consistent with larger shear-induced NMDG+ currents in TAC rat atrial myocytes. P2X4R expression increased in 5-wk-TAC atrial cells, but decreased in 4-mon-TAC atrial cells. On the other hand, P2Y1R-dependent longitudinal Ca2+ waves and P2Y1R expression were significantly increased by 4-mon-TAC. Our data suggest that Cx43-P2 receptor-mediated shear signaling is significantly altered by the progress of atrial dilation and volume overload, and that biphasic changes in P2X4R function and expression versus TAC duration may play a role in the progression from hypertrophy to failure in atrium subjected to aortic stenosis and increased afterload.

Favorable Effects of Sacubitril/Valsartan on the Peak Atrial Longitudinal Strain in Patients With Chronic Heart Failure and a History of One or More Episodes of Atrial Fibrillation: A Retrospective Cohort Study.

BackgroundThe peak atrial longitudinal strain (PALS) is primarily an index of the reservoir function of atrial chambers. The conceptual basis exists to hypothesize that sacubitril/valsartan improves the expandability of atrial chambers in the reservoir phase of the atrial mechanical cycle, as a consequence of its effect of prolonging the half-life of natriuretic peptides. Therefore in this retrospective study we evaluated the repercussions of the administration of sacubitril/valsartan maintained for at least 12 months on the PALS.MethodsIn our retrospective study a cohort of 40 patients treated with sacubitril/valsartan has been compared with a second cohort subjected to the conventional treatment with an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker. A general criterion to be satisfied was the presence of at least one episode of atrial fibrillation (AF) in the history of the enrolled patients. The study population was composed of New York Heart Association (NYHA) class II/III chronic heart failure (CHF) patients, due to the fact that the treating physicians of the patients whose clinical records were used as source of data, complied with the international guidelines that have so far validated sacubitril/valsartan exclusively for the CHF therapy. The aims were to verify whether the 1-year administration of sacubitril/valsartan is effective in improving the PALS, and also ascertain whether the drug is associated with a decreased risk of AF relapses over a mean retrospective observation period of 12 months.ResultsSacubitril/valsartan cohort was proven to benefit from a significant increase in average values of PALS (median: 26.5%; interquartile range (IQR): 22% - 30%), opposed to the much less pronounced increase in PALS found in the conventional therapy cohort (median: 22.5%; IQR: 18% - 25.5%). Additionally, the comparison made by means of one-way analysis of variance regarding the mean changes of PALS values, outlined clearly that the sacubitril/valsartan users had an increase in PALS after 1 year of therapy significantly greater (P < 0.001) compared to the patients taking the conventional drugs. Moreover, a risk significantly higher of AF recurrences (P = 0.001) was identified in the conventional therapy group compared to the sacubitril/valsartan group during a 12-month retrospective observation period.ConclusionsIn the present retrospective cohort study a higher increase of PALS has been shown in the cohort treated with sacubitril/valsartan. Moreover, a reduced risk of AF recurrences has been shown in the sacubitril/valsartan users compared to the patients with CHF subjected to conventional treatment.

P687 Left atrial mass - a potential pitfall

Abstract Background. Echocardiography is an important diagnostic tool in differential diagnosis of retrosternal pain. Despite the high prevalence of hiatus hernia, a relatively small number of echocardiographically manifested cases have been reported. Case summary. A 75 y old female patient with rheumatic polymialgia and diabetes was admitted for progressive weakness, retrosternal pain and dyspnoea. Due to elevated levels of D-dimer and troponin I an urgent CT angiography was performed and a diagnosis of pulmonary embolism was confirmed in the ER. Echocardiography showed a mildly hypertrophied left ventricle with normal EF, a mildly dilated right ventricle, moderate pulmonary hypertension 45 mmHg, and an apparent mass in the left atrium (picture). To further characterize the left atrial mass a cardiac MR angiography was made, that excluded potential cardiac tumor and confirmed that the suspected mass was a large hiatus hernia impressing the left atrium. Patient was treated with anticoagulant therapy due to PE and corticosteroids due to polymialgia and was discharged in improved condition. We also consulted thoracic surgeons regarding hernia and did not decide to operate on the hernia urgently but opted for conservative reflux measures and an outpatient follow up with barium contrast oesophagus imaging. Discussion. Hiatal hernia may exert a wide spectrum of manifestations mimicking acute cardiovascular events, from ECG changes to angina, dyspnoea and even syncope as a consequence of total compression of the left atrium. A history of known hiatus hernia and aforementioned clinical correlates postprandially may shed some clues. Echocardiographic features that may suggest a hiatus hernia include: 1. A large ill-defined mass filling the left atrial chamber from posteriorly, with its maximal size seen when imaged in a posterior plane. 2. Respiratory variation in the degree of encroachment of the mass on the left atrium. 3. Loss of the normal sharply defined sonolucency of the descending thoracic aorta in the apical 4-chamber and long-axis views due to superimposition of the hiatus hernia. 4. A swirling motion seen within the mass after consumption of effervescent fluids. 5. Occasionaly, identification of an inner lining reminiscent of gastric mucosa is possible. Various intracardiac or extrinsic lesions can resemble the echocardiographic appearance of hiatus hernia. Other potential causes of extracardiac masses that could encroach on the left atrium include structures such as aneurysm or dissection of the aorta, dilation of coronary sinus, abcesses, oesophageal carcinoma and other mediastinal space occupying structures. Conclusion. Hiatus hernia can simulate clinical and sonographic characteristics of cardiac disorders. Its echocardiographic manifestation may mimic a left atrial mass and must therefore be differentiated from such lesions. Abstract P687 Figure. Hiatal hernia mimicking LA mass(PLAX)

A Systematic Review of a Long-forgotten Cause of Atrial Fibrillation and Stroke: Cor Triatriatum.

Cor triatriatum is a rare congenital cardiac condition characterized by the division of one atrium into two chambers by a fibromuscular membrane, resulting in three atrial chambers. The goal of this study was to determine the associations of cor triatriatum with cyanosis, atrial fibrillation (AF), and stroke.MEDLINE (PubMed, Ovid), Embase, and Cochrane databases were searched on April 25, 2019, for relevant articles on cor triatriatum. After initial screening and removal of duplicates, 235 articles were selected. Data were extracted from these articles, including types, presentations, diagnostic findings, management, and outcomes of patients with cor triatriatum.Approximately 83% of patients with cor triatriatum had cor triatriatum sinistrum (CTS) and 17% had cor triatriatum dextrum (CTD). The mean age of all patients was 29±23 years. Mean ages at diagnosis differed significantly in patients with CTS and CTD (31±23 years vs. 21±20 years, p=0.02). CTS showed a significantly greater association with AF (14.65% vs. 12.5%, p=0.036) and had a substantially higher risk of stroke (7.9% vs. 5.0%, p=0.04) than CTD. CTS also had a numerically higher association with atrial septal defects (15.13% vs. 15.6%), but this difference was not statistically significant (p=0.89). In contrast, cyanosis at presentation was significantly more frequent in patients with CTD than CTS (5.5% vs. 5.3%, p=0.05). Management did not differ significantly between these groups (p=0.29). The overall mortality rate was 16%, with no significant difference between patients with CTS and CTD (p=0.33).The higher likelihood of AF and stroke in CTS than in CTD patients warrants treatment of the former with anticoagulation agents, irrespective of their CHA₂DS₂-VASc scores (congestive heart failure, hypertension, age, diabetes mellitus, stroke, vascular disease, age, sex category). Patients with CTS usually present at an older age due to their lower risk of cyanosis and asymptomatic AF.

P5568Disease stages of structural and functional cardiac changes associate with outcomes in patients with mitral regurgitation receiving mitral valve intervention

Abstract Background/Introduction Severe mitral regurgitation (MR) produces volume overload resulting in progressive cardiac dysfunction that can extend beyond the left-sided chambers. It is unknown whether a specific MR staging system, that would quantify the extent of structural and functional cardiac changes, would be associated with outcomes in severe MR patients receiving mitral valve (MV) intervention. Purpose To examine the clinical utility of a novel MR staging system, based on the extent of cardiac damage, for prediction of clinical outcomes for patients with severe MR who underwent surgical or transcatheter therapy. Methods Patients were categorized into five stages using pre-procedural echocardiography; Stage 0: no other cardiac damage detected; Stage 1: Left atrium (LA) abnormality, as defined by the presence of atrial fibrillation or LA chamber enlargement; Stage 2: LV dysfunction, as defined by LV ejection fraction &lt;60%; Stage 3: Pulmonary artery vasculature or tricuspid valve abnormality, as defined by the presence of systolic pulmonary arterial pressure ≥60 mmHg) or ≥grade 2 tricuspid regurgitation; and Stage 4: Right ventricular (RV) disease as defined by the presence of &gt;mild RV dysfunction. The primary outcomes were all-cause mortality, and the combined endpoint of death or heart failure rehospitalization at one-year follow-up. Results A total of 696 patients with MR (age 70±14 years; 60% men) who underwent MV surgery (69%) or transcatheter MV repair with MitraClip device (31%) were examined. Prevalences of stage 0, 1, 2, 3, and 4 were 6.6%, 34.6%, 20.0%, 26.6%, and 12.2%, respectively. The median follow-up time was 15 months (IQR, 6.4, 24.4 months). At one-year, there was graded increase in all-cause death and in the combined endpoint of death or heart failure rehospitalization with each MR stage (Figure). In multivariate models, these associations remained independently associated with both one-year endpoints for patients receiving either surgical or transcatheter interventions. Figure 1 Conclusion This novel MR staging system is practical and may improve clinical risk stratification of patients with severe MR being considered for MV interventions.

P2458Restricted left atrial motion as a result of atrial stiffening in patients with cardiac amyloidosis

Abstract Background Left atrial (LA) involvement of abnormal amyloid fibrils could induce LA dysfunction and stiffening in patients with cardiac amyloidosis (CA). Thus, the assessments of LA function and stiffness might be a potential approach to diagnose CA phenotype among patients with hypertrophied hearts. Purpose We sought to determine whether LA reservoir strain with speckle tracking echocardiography could be used a marker of LA stiffness in a derivation cohort. Furthermore, we tested to our hypothesis that LA reservoir strain could differentiate CA patients from hypertrophic cardiomyopathy (HCM) in an independent validation cohort. Methods In the derivation cohort, echocardiography was performed simultaneously with measurements of pulmonary capillary wedge pressure (PCWP) in 50 patients with suspected or established heart failure and relatively preserved left ventricular (LV) ejection fraction (56±10%). LA maximum and minimum volume index, and reservoir strain were measured from apical four-chamber view. LA stiffness index was computed as a pressure rise from x-trough to v-wave divided by an increase from minimum to maximum indexed LA volume (Figure A). In an independent validation group, we studied a total of 33 biopsy-proved CA patients and 127 HCM patients (LV ejection fraction: 57±11% vs. 66±10%, P&lt;0.01) in sinus rhythm on the date of comprehensive echocardiographic study. Among them, cardiac magnetic resonance imaging (CMR) could be evaluated in 17 CA patients and 98 HCM patients. Furthermore, right heart catheterization was performed with 12 CA patients and 12 HCM patients in the CMR group. Results The derivation cohort study found that there was a significant curvilinear correlation of LA reservoir strain to LA stiffness index (Figure B). In the validation cohort, LA reservoir strain was reduced in patients with CA compared with HCM in all participants (11.6±5.6% vs. 18.5±6.9%, P&lt;0.01), although there was no significant difference of LA maximal volume index between 2 groups (37±16 ml/m2 vs. 37±12 ml/m2, p=0.89). In the CMR group, the late gadolinium enhancement was observed in the LA wall in 16 patients with CA (94.1%) as shown in Figure C. In contrast, the LA enhancement revealed only in 1 patient with HCM (1.0%). Among patients with invasive measures, LA stiffness index [median (interquartile range)] was higher in patients with CA than that in patients with HCM [1.1 (0.4–2.8) vs. 0.2 (0.1–0.6), P=0.01]. Conclusions LA reservoir function was fairly limited in patients with CA compared with HCM. Restricted LA motion might be related to atrial amyloid deposits or fibrosis, which potentially provokes atrial chamber stiffening.

P4365Role of 3D speckle-tracking echocardiography system, using comparison with cardiac magnetic resonance imaging and to assess the contribution of regional RV function to global function in COPD patients

Abstract Background Chronic obstructive pulmonary disease may alter right and left ventricular function by changing intrathoracic pressure. Pulmonary hyperinflation may increase right atrial pressure, leading to reduced venous return and subsequent reductions in RV pre-load. In COPD patients, hyperinflation has been directly correlated with reduced atrial chamber size, global RV dysfunction, and reduced LV filling. Accurate assessment of global and regional right ventricular (RV) systolic function is challenging. Purpose The aims of this study were to confirm the reliability and feasibility of a three-dimensional (3D) speckle-tracking echocardiography (STE) system, using comparison with cardiac magnetic resonance imaging (CMR), and to assess the contribution of regional RV function to global function. Methods In a retrospective, cross-sectional study setting, RV volumetric data were studied in 302 patients who were referred for both CMR and 3D echocardiography within 1 month. Three-dimensional STE-derived area strain, longitudinal strain, and circumferential strain were assessed as global, inlet, outflow, apical, and septal segments. Results 208 patients (69%) had adequate 3D echocardiographic data. RV measurements derived from 3D STE and CMR were closely related (RV end-diastolic volume, R2=0.88; RV end-systolic volume, R2=0.81; RV ejection fraction [RVEF], R2=0.69; P&lt;0.004 for all). RVEF and RV end-diastolic volume from 3D STE were slightly but significantly smaller than CMR values (mean differences, −2.8% and −7.8 mL for RVEF and RV end-diastolic volume, respectively). Among conventional echocardiographic parameters for RV function (tricuspid annular plane systolic excursion, fractional area change, S' of the tricuspid annulus, RV free wall two-dimensional longitudinal strain), only fractional area change was significantly related to RVEF (r=0.29, P=0.003). Among segmental 3D strain variables, inlet area strain (r=−0.48, P&lt;0.002) and outflow circumferential strain (r=−0.37, P&lt;0.003) were independent factors associated with CMR-derived RVEF. Conclusions Regional RV wall motion showed that heterogeneous segmental deformations affect global RV function differently; specifically, inlet area strain and outflow circumferential strain.RV volume and RVEF determined by STE were comparable with CMR measurements. Severity of COPD influences RV systolic dysfunction, which is reflected in speckle tracking 3D echocardiographic parameters.

P4356Assessment of global and regional right ventricular systolic function in restrictive pulmonary disease by novel speckle tracking 3D echocardiography comparison with cardiac magnetic resonance imaging

Abstract Background Chronic restrictive pulmonary disease may alter right and left ventricular function by changing intrathoracic pressure. Pulmonary hyperinflation may increase right atrial pressure, leading to reduced venous return and subsequent reductions in RV pre-load. In CRPD patients, hyperinflation has been directly correlated with reduced atrial chamber size, global RV dysfunction, and reduced LV filling. Accurate assessment of global and regional right ventricular (RV) systolic function is challenging. Purpose The aims of this study were to confirm the reliability and feasibility of a three-dimensional (3D) speckle-tracking echocardiography (STE) system, using comparison with cardiac magnetic resonance imaging (CMR), and to assess the contribution of regional RV function to global function. Methods In a retrospective, cross-sectional study setting, RV volumetric data were studied in 200 patients who were referred for both CMR and 3D echocardiography within 1 month. Three-dimensional STE-derived area strain, longitudinal strain, and circumferential strain were assessed as global, inlet, outflow, apical, and septal segments. Results 136 patients (68%) had adequate 3D echocardiographic data. RV measurements derived from 3D STE and CMR were closely related (RV end-diastolic volume, R2=0.89; RV end-systolic volume, R2=0.82; RV ejection fraction [RVEF], R2=0.68; P&lt;0.003 for all). RVEF and RV end-diastolic volume from 3D STE were slightly but significantly smaller than CMR values (mean differences, −3% and −8 mL for RVEF and RV end-diastolic volume, respectively). Among conventional echocardiographic parameters for RV function (tricuspid annular plane systolic excursion, fractional area change, S' of the tricuspid annulus, RV free wall two-dimensional longitudinal strain), only fractional area change was significantly related to RVEF (r=0.30, P=0.005). Among segmental 3D strain variables, inlet area strain (r=−0.49, P&lt;0.004) and outflow circumferential strain (r=−0.39, P&lt;0.005) were independent factors associated with CMR-derived RVEF. Conclusions Severity of restrictive pulmonary disease influences RV systolic dysfunction, which is reflected in speckle tracking 3D echocardiographic parameters. Regional RV wall motion showed that heterogeneous segmental deformations affect global RV function differently; specifically, inlet area strain and outflow circumferential strain.RV volume and RVEF determined by STE were comparable with CMR measurements.

P615Role of three-dimensional (3D) speckle-tracking echocardiography (STE) system, using comparison with cardiac magnetic resonance imaging (CMR) and to assess the contribution of regional RV function to

Abstract Background Chronic obstructive pulmonary disease may alter right and left ventricular function by changing intrathoracic pressure. Pulmonary hyperinflation may increase right atrial pressure, leading to reduced venous return and subsequent reductions in RV pre-load. In COPD patients, hyperinflation has been directly correlated with reduced atrial chamber size, global RV dysfunction, and reduced LV filling. Accurate assessment of global and regional right ventricular (RV) systolic function is challenging. Purpose The aims of this study were to confirm the reliability and feasibility of a three-dimensional (3D) speckle-tracking echocardiography (STE) system, using comparison with cardiac magnetic resonance imaging (CMR), and to assess the contribution of regional RV function to global function. Methods In a retrospective, cross-sectional study setting, RV volumetric data were studied in 302 patients who were referred for both CMR and 3D echocardiography within 1 month. Three-dimensional STE-derived area strain, longitudinal strain, and circumferential strain were assessed as global, inlet, outflow, apical, and septal segments. Results 208 patients (69%) had adequate 3D echocardiographic data. RV measurements derived from 3D STE and CMR were closely related (RV end-diastolic volume, R2=0.88; RV end-systolic volume, R2=0.81; RV ejection fraction [RVEF], R2=0.69; P&lt;0.004 for all). RVEF and RV end-diastolic volume from 3D STE were slightly but significantly smaller than CMR values (mean differences, −2.8% and −7.8 mL for RVEF and RV end-diastolic volume, respectively). Among conventional echocardiographic parameters for RV function (tricuspid annular plane systolic excursion, fractional area change, S' of the tricuspid annulus, RV free wall two-dimensional longitudinal strain), only fractional area change was significantly related to RVEF (r=0.29, P=0.003). Among segmental 3D strain variables, inlet area strain (r=−0.48, P&lt;0.002) and outflow circumferential strain (r=−0.37, P&lt;0.003) were independent factors associated with CMR-derived RVEF. Conclusions Regional RV wall motion showed that heterogeneous segmental deformations affect global RV function differently; specifically, inlet area strain and outflow circumferential strain.RV volume and RVEF determined by STE were comparable with CMR measurements. Severity of COPD influences RV systolic dysfunction, which is reflected in speckle tracking 3D echocardiographic parameters.

A robust computational framework for estimating 3D Bi-Atrial chamber wall thickness

Atrial fibrillation (AF) is the most prevalent form of cardiac arrhythmia. The atrial wall thickness (AWT) can potentially improve our understanding of the mechanism underlying atrial structure that drives AF and provides important clinical information. However, most existing studies for estimating AWT rely on ruler-based measurements performed on only a few selected locations in 2D or 3D using digital calipers. Only a few studies have developed automatic approaches to estimate the AWT in the left atrium, and there are currently no methods to robustly estimate the AWT of both atrial chambers. Therefore, we have developed a computational pipeline to automatically calculate the 3D AWT across bi-atrial chambers and extensively validated our pipeline on both ex vivo and in vivo human atria data. The atrial geometry was first obtained by segmenting the atrial wall from the MRIs using a novel machine learning approach. The epicardial and endocardial surfaces were then separated using a multi-planar convex hull approach to define boundary conditions, from which, a Laplace equation was solved numerically to automatically separate bi-atrial chambers. To robustly estimate the AWT in each atrial chamber, coupled partial differential equations by coupling the Laplace solution with two surface trajectory functions were formulated and solved. Our pipeline enabled the reconstruction and visualization of the 3D AWT for bi-atrial chambers with a relative error of 8% and outperformed existing algorithms by >7%. Our approach can potentially lead to improved clinical diagnosis, patient stratification, and clinical guidance during ablation treatment for patients with AF.

Biomechanical signaling within the developing zebrafish heart attunes endocardial growth to myocardial chamber dimensions

Intra-organ communication guides morphogenetic processes that are essential for an organ to carry out complex physiological functions. In the heart, the growth of the myocardium is tightly coupled to that of the endocardium, a specialized endothelial tissue that lines its interior. Several molecular pathways have been implicated in the communication between these tissues including secreted factors, components of the extracellular matrix, or proteins involved in cell-cell communication. Yet, it is unknown how the growth of the endocardium is coordinated with that of the myocardium. Here, we show that an increased expansion of the myocardial atrial chamber volume generates higher junctional forces within endocardial cells. This leads to biomechanical signaling involving VE-cadherin, triggering nuclear localization of the Hippo pathway transcriptional regulator Yap1 and endocardial proliferation. Our work suggests that the growth of the endocardium results from myocardial chamber volume expansion and ends when the tension on the tissue is relaxed.

The value of three-dimensional echocardiography in the evaluation of cor triatrium sinister

Introduction Cor triatrium sinister is a very rare congenital heart disease in which the pulmonary veins enter a proximal accessory left atrial chamber that is separated from a distal true left atrial chamber by a fibromuscular membrane presenting one or more ostia. Its incidence in the adulthood is extremely rare. Adult patients are symptomatic in case the orifice across the membrane becomes obstructive mimicking a mitral stenosis. It has been reported that severe obstruction is present if maximum doppler velocity across the orifice is more than 2 m/s.1 However, in a review of case series no correlation could be found between the pressure gradient across the fenestration and the clinical symptoms.2 We report the case of a symptomatic adult female with obstructive cor triatrium in whom the intraoperative three-dimensional transesophageal echocardiography (3D TEE) revealed the severity of obstruction in contrast to the mild intraoperative pressure gradients. Methods A 34-year-old female was scheduled for surgical repair of a cor triatrium sinister. The symptoms of dyspnea had increased during the last months (NYHA III) which resulted in the echocardiographic diagnosis. The mean pressure gradient across the orifice was estimated 6 mmHg at rest and 18 mmHg at effort using modified Bernoulli equation. There were no associated cardiac abnormalities and no signs of pulmonary hypertension. The patient gave written consent to present her case. Results The induction of anesthesia was performed with the aim to keep hemodynamic stability. The intraoperative TEE confirmed the diagnosis. Color flow across the orifice showed an aspect of rather laminar flow. The mean pressure gradient across the sole orifice was 2 mmHg.Three-dimensional en face view of the membrane permitted offline analysis of the lesion in several orthogonal planes and measurement of the effective opening area of the orifice which was 1.45 cm2 (Fig 1). Discussion This case illustrates that pressure gradient across an obstructive cor triatrium may underestimate the true severity of the lesion as the blood flow may be low through the channel. Therefore, 3D echocardiography should be routinely performed in patients with cor triatrium in order to measure the exact maximal fenestration orifice area.

Development of an in vitro test procedure for the characterization of left atrial appendage occluder devices

Abstract The implantation of an occluder in the left atrial appendage (LAA) is an emerging therapy for the treatment of patients suffering from atrial fibrillation and with a contraindication to oral anticoagulation. The LAA occluder (LAAO) provides a reduction of the potential risk of strokes by thromboembolism. Currently, only a few CE-approved devices are available on the market and the number of clinical trials is comparatively low. Furthermore, there is currently no standardized test method available for testing functionality of the occluder, especially for testing safe anchorage and permeability. Therefore, the aim of this study is to establish an in vitro test method to prove anchorage mechanism and permeability regarding thromboembolism of the LAAO under physiological conditions. A standardized technical and fully parameterized silicone model of a LAA, based on studies of different morphologies and sizes, was developed. The LAA model was mounted onto the left atrial chamber of a commercial pulse duplicator system to simulate physiological hemodynamic conditions. The test was performed using the Watchman device (Boston Scientific, USA; size: 31 mm). The inner implantation diameter of the LAA model was designed according to a target compression of 10% for the Watchman device in the implanted configuration. Furthermore, thrombus-like particles (n=150, d=1,7±0,05 mm) were added to represent the flushing of thrombi out of the LAA after device implantation. Within several cycles it was confirmed that no particles were washed out of the LAA model with the implanted occluder leading to a full protection against thromboembolism. It could also be shown that the occluder is firmly anchored in the LAA. Pressure measurements with sensors in the left atrium and in the LAA distal to the occluder could also show that the occluder has no influence on the pressure conditions in the LAA.

Correction to: 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

Correction to: 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

The Role of Non-Coding RNA in Congenital Heart Diseases.

Cardiovascular development is a complex developmental process starting with the formation of an early straight heart tube, followed by a rightward looping and the configuration of atrial and ventricular chambers. The subsequent step allows the separation of these cardiac chambers leading to the formation of a four-chambered organ. Impairment in any of these developmental processes invariably leads to cardiac defects. Importantly, our understanding of the developmental defects causing cardiac congenital heart diseases has largely increased over the last decades. The advent of the molecular era allowed to bridge morphogenetic with genetic defects and therefore our current understanding of the transcriptional regulation of cardiac morphogenesis has enormously increased. Moreover, the impact of environmental agents to genetic cascades has been demonstrated as well as of novel genomic mechanisms modulating gene regulation such as post-transcriptional regulatory mechanisms. Among post-transcriptional regulatory mechanisms, non-coding RNAs, including therein microRNAs and lncRNAs, are emerging to play pivotal roles. In this review, we summarize current knowledge on the functional role of non-coding RNAs in distinct congenital heart diseases, with particular emphasis on microRNAs and long non-coding RNAs.