Left Ventricular Shape Research Articles

Percutaneous Ventricular Restoration with a Partitioning Device for Ischemic Heart Failure Treatment.

Percutaneous ventricular restoration with a ventricular partitioning device (VPD) is a novel minimally invasive procedure designed to restore the left ventricular (LV) shape by isolating the infarcted and aneurysmal LV apex from remainder of the cavity in heart failure patients with severely reduced LV ejection fraction. In this review, we perform an in-depth analysis of the design and purpose of the VPD and review the available clinical data, with special attention to hemodynamics, outcomes, and complications. PARACHUTE trials have shown >90% procedural success rate of VPD implant. Heart failure patients had improvement in hemodynamics (reduction in LV volumes and increase in LV ejection fraction) and functional status (6-min walking distance and quality of life scores) after the VPD implant. Optimal implant position is necessary to obtain a good clinical outcome. Percutaneous VPD implantation has thus far been a safe intervention capable of improving surrogate markers of heart failure but there is still a need to develop more durable devices with a long-lasting hemodynamics effect.

Invited Commentary

Undersizing mitral annuloplasty (UMA) has emerged as a mitral repair technique of choice to correct ischemic mitral regurgitation (IMR). Despite the unphysiological leaflet coaptation that results from this repair and the potential deleterious impact that restricting mitral annular dynamics and basal myocardial contraction may have on left ventricular function, extensive surgical experience with UMA and its procedural ease makes this a procedure of choice. However, to achieve better long-term patient outcomes after UMA, the adverse impact of UMA on the valve and the ventricle needs to be better understood. In this study, Pantoja and colleagues [1Pantoja J.L. Morgan A.E. Grossi E.A. et al.Undersized mitral annuloplasty increases strain in the proximal lateral left ventricular wall.Ann Thorac Surg. 2017; 103: 820-827Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar] use a finite element model of an IMR-like left ventricle to demonstrate that UMA impacts basal myocardial mechanics and acutely alters left ventricular shape. Specifically, the end-diastolic longitudinal strain in the lateral left ventricular wall was elevated when compared with the preoperative configuration, but the fiber strain in the same region was decreased. The authors conclude that UMA induced changes in left ventricular shape and that mechanics can trigger continued remodeling of the ventricle and result in recurrent IMR and poor ventricular function. This is a nicely done computational study, albeit with some limitations, which follow:1.Preannuloplasty annular size and shape—in the clinical scenario, the mitral annular sizes, shapes, and extent of dilatation differs significantly between patients, and the effect of an annuloplasty ring on each annulus may be variable. Despite using 5 sheep-specific models in this study, the variability in annular geometry and its impact on postannuloplasty strains were not investigated.2.Impact of IMR correction—Annuloplasty acutely abolishes IMR and thus reduces. Reduced end-diastolic strain may reduce the impact that the ring may have on the ventricular shape and mechanics. The computational model does not consider the physiological effects of the ring on the ventricle.3.The distinction of the myocardium into layers is only hypothetical and not ultrastructure driven in this model. Specifically, the infarcted myocardium is thinned, lacks distinct layers, and is often stiffened from fibrosis. The computational model did not seem to consider these regional structural features, which may have an impact on the reported strains. Notwithstanding these limitations, this study provides some preliminary insights into the deleterious impact that undersizing annuloplasty may have on the left ventricle. However, whether it causes continued left ventricular remodeling or impairs systolic function remains speculative at best and needs careful experimental validation. In 2012, Shudo and coworkers [2Shudo Y. Nakatani S. Sakaguchi T. et al.Left ventricular mechanics following restrictive mitral annuloplasty for functional mitral regurgitation: two dimensional speckle tracking echocardiographic study.Echocardiography. 2012; 29: 445-450Crossref PubMed Scopus (4) Google Scholar] investigated left ventricular mechanics at 4 weeks after UMA in patients with IMR and reported that ejection fraction and longitudinal strains were largely unaltered. Radial and longitudinal strains were improved at the mid and apical levels but were unaltered at the base of the ventricle. Left ventricular twist was significantly elevated in these patients after UMA, compared with their preoperative measurements. The discrepancy between such improved left ventricular mechanics in patients who underwent UMA and the adverse impact suggested in this simplified computational model will need to be explained for clinical translation of these findings. Undersized Mitral Annuloplasty Increases Strain in the Proximal Lateral Left Ventricular WallThe Annals of Thoracic SurgeryVol. 103Issue 3PreviewRecurrence of mitral regurgitation (MR) after undersized mitral annuloplasty (MA) for ischemic MR is as high as 60%, with the recurrence rate likely due to continued dilation of the left ventricle (LV). To better understand the causes of recurrent MR, we studied the effect of undersized MA on strain in the LV wall. We hypothesize that the acute change in ventricular shape induced by MA will cause increased strain in regions nearest the mitral valve. Full-Text PDF

Orthogonal decomposition of left ventricular remodeling in myocardial infarction

Left ventricular size and shape are important for quantifying cardiac remodeling in response to cardiovascular disease. Geometric remodeling indices have been shown to have prognostic value in predicting adverse events in the clinical literature, but these often describe interrelated shape changes. We developed a novel method for deriving orthogonal remodeling components directly from any (moderately independent) set of clinical remodeling indices. Results: Six clinical remodeling indices (end-diastolic volume index, sphericity, relative wall thickness, ejection fraction, apical conicity, and longitudinal shortening) were evaluated using cardiac magnetic resonance images of 300 patients with myocardial infarction, and 1991 asymptomatic subjects, obtained from the Cardiac Atlas Project. Partial least squares (PLS) regression of left ventricular shape models resulted in remodeling components that were optimally associated with each remodeling index. A Gram–Schmidt orthogonalization process, by which remodeling components were successively removed from the shape space in the order of shape variance explained, resulted in a set of orthonormal remodeling components. Remodeling scores could then be calculated that quantify the amount of each remodeling component present in each case. A one-factor PLS regression led to more decoupling between scores from the different remodeling components across the entire cohort, and zero correlation between clinical indices and subsequent scores. Conclusions: The PLS orthogonal remodeling components had similar power to describe differences between myocardial infarction patients and asymptomatic subjects as principal component analysis, but were better associated with well-understood clinical indices of cardiac remodeling. The data and analyses are available from www.cardiacatlas.org.

Depleted Leukocyte Mitochondrial DNA Copy Number Correlates With Unfavorable Left Ventricular Volumetric and Spherical Shape Remodeling in Acute Myocardial Infarction After Primary Angioplasty.

Left ventricular (LV) shape influences LV systolic function. It is possible to assess LV shape using 3-D echocardiography sphericity index (SI). Maintaining mitochondrial DNA copy number (MCN) is important for preserving mitochondrial function and LV systolic function after acute myocardial infarction (AMI). Information is limited, however, regarding the relationship between leukocyte MCN and the subsequent change in LV shape after AMI.Methods and Results:Fifty-five AMI patients undergoing primary angioplasty were recruited. Plasma MCN was measured before primary angioplasty using quantitative polymerase chain reaction. 3-D echocardiography measurement of SI was performed at baseline, and at 1-, 3-, and 6-month follow-up. AMI subjects with MCN lower than the median had a higher 6-month SI and LV volume compared with those with higher MCN. Baseline echocardiographic parameters were similar between the 2 groups. MCN was negatively correlated with 3- and 6-month SI, and 3- and 6-month LV volume. On multiple linear regression analysis, baseline plasma MCN could predict LV SI and LV volume at 6 months after primary angioplasty for AMI, even after adjusting for traditional prognostic factors. In AMI patients, higher plasma leukocyte MCN at baseline was associated with favorable LV shape and remodeling at 6-month follow-up. Plasma leukocyte MCN may provide a novel prognostic biomarker for LV remodeling after AMI.

Real-time 3-dimensional transesophageal echocardiography assessment of left ventricular shape and function after surgical remodelling

BackgroundReal-time three dimensional transoesoph-ageal echocardiography (RT 3D-TEE) may better reflect left ventricle (LV) shape and function than cconventional 2D-TEE. The goal of this study was to evaluate the ad-vantages of 3D analysis in shape assessment and to quantify the LV volume by ejection fraction (EF) measurement, after LV surgi-cal remodelling.MethodsIn a prospective manner, twenty consecu-tive coronary surgery patients with LV an-teroapical aneurysm and functional mitral regurgitation were analyzed by 2D- and thereafter by 3D- TEE before and after surgery. The key intraoperative inclusion criteria was a LVEF < 30% confirmed by intraoperative 3D-TEE immediately before surgical remodeling.ResultsBefore surgery, the geometry of post infarc-tion aneurysm shows negative curvatures of the antero-basal and infero-apical seg-ment and the apex of LV is shifted clock-wise, towards the mitral valve. Surgery had significantly reduced the LV volumes and the LVEF had increased by 13.3% as recorded by 2D-TEE and by 18.3% as as-sessed by 3D-TEE quantification (p < 0.001 for both). Accordingly, the longitudinal plane had been shortened, the apex was now shifted anti-clockwise towards the aorta and the inferior region had taken a more important function of the LV. Signifi-cantly lower values were observed in the EF measurement with 3D- vs 2D-TEE before remodelling (22.3 vs. 29.7%, p = 0.048). ConclusionImprovement of LV function occurred due to the increased systolic contraction of the inferior region after remodelling in pa-tients with postinfarction aneurysm.

Left ventricular shape predicts different types of cardiovascular events in the general population

ObjectiveTo investigate whether sphericity volume index (SVI), an indicator of left ventricular (LV) remodelling, predicts incident cardiovascular events (coronary heart disease, CHD; all cardiovascular disease, CVD; heart failure, HF; atrial...

Three-Dimensional Transthoracic Echocardiography in the Comprehensive Evaluation of Right and Left Heart Chamber Remodeling Following Percutaneous Mitral Valve Repair

Percutaneous mitral valve repair (PMVR) is an alternative treatment in patients with significant mitral regurgitation (MR) who are denied surgery. Although in surgical patients, outcomes have been related both to acute hemodynamic favorable results and to positive cardiac remodeling in the midterm, in the case of PMVR the effect on cardiac chamber remodeling has never been extensively studied. The aims of this study were (1) to evaluate the short- and mid-term remodeling induced by PMVR on cardiac chamber volume using two- and three-dimensional (3D) transthoracic echocardiographic (TTE) imaging and (2) to assess changes in left ventricular (LV) shape on the basis of 3D TTE data. Patients undergoing PMVR were prospectively enrolled. Two-dimensional and 3D TTE data sets acquiredat baseline, and at 30days and 6months after PMVR were analyzed to assess LV and right ventricular (RV) volumes and ejection fraction and left atrial and right atrial volumes. Moreover, 3D endocardial surfaces were extracted to compute 3D shape indexes of LV sphericity and conicity at end-diastole and end-systole. Six of the 64 enrolled patients did not reach follow-up and were excluded. The analysis was feasible inall 58 patients considered (26 with functional MR and 32 [55%] with degenerative MR). PMVR resulted in significantreduction of MR and in favorable remodeling: (1) effective PMVR was mainly associated with decreased LV loading, (2) PMVR-related reverse remodeling was observed in patients with degenerative MR and those with functional MR at 30days and continued at 6-month follow-up, (3) favorable remodeling in LV shape from abnormally spherical to more normal conical took place in both groups after PMVR, and (4) RV volumes and systolic function were preserved after PMVR. A comprehensive two-dimensional and 3D TTE analysis allows investigation from a double perspective (volume and morphology) of the entity and modality of changes following PMVR. In high-risk patients undergoing PMVR, postprocedural heart remodeling involves all cardiac chambers, occurs in the short term, and further improves at midterm follow-up.

Left ventricular outflow tract obstruction in ICU patients.

Left ventricular (LV) outflow tract (LVOT) obstruction (LVOTO) is not unusual in ICU patients particularly with septic shock. LVOT was first described in patients with hypertrophic cardiomyopathy and was defined as LV wall thickness at least 15 mm. LVOT is usually because of systolic anterior motion of the mitral valve. By convention, LVOTO is defined as an instantaneous peak Doppler LVOT pressure gradient at least 30 mmHg at rest or during physiological provocation such as Valsalva maneuver. Recently, it has been demonstrated that LVOT can be present in patients with severe hypovolemia or hyperkinesia with or without LV hypertrophy and can lead to hemodynamic compromise. LVOT is because of a combination of precipitating factors, which may or may not be associated with anatomical abnormalities. Decreased preload because of hypovolemia or decreased afterload because of septic shock, increased heart rate, and LV hyperkinesis produced by dobutamine infusion can induce a change of LV shape and induce LVOTO. LVOTO is not uncommon in ICU patients and can be observed at the early phase of septic shock. Treatment should include discontinuation of dobutamine infusion and fluid infusion. β blockers can be useful in this clinical situation.

Foundations of Pharmacotherapy for Heart Failure With Reduced Ejection Fraction: Evidence Meets Practice, Part I.

Pharmacologic treatment for systolic heart failure, otherwise known as heart failure with reduced ejection fraction, has been established through clinical trials and is formulated into guidelines to standardize the diagnosis and treatment. The premise of pharmacologic therapy in heart failure with reduced ejection fraction is aimed primarily at interrupting the neurohormonal cascade that is responsible for altering left ventricular shape and function. This is the first in a series of articles to describe the pharmacologic agents in the guidelines that impact the morbidity and mortality associated with heart failure. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and vasodilators will be presented in the context of the mechanism of action in heart failure, investigational trials that showed beneficial effects, and the practical application for clinical use.

Left ventricular shape variation in patients with aortic coarctation pre- and post-stent implantation

Background Coarctation of the aorta (CoA) affects about 4 out of every 10,000 babies born and requires lifelong followup. Even after successful early repair, late cardiovascular (CV) complications arise. In adult patients, left ventricular remodeling (LVR) patterns can predict CV risk. However, few studies on LVR of CoA patients exist due to lack of detailed geometric models. The Cardiac Atlas Project (CAP), a worldwide consortium for pooling standardized analyses of cardiac images for mapping heart shape and motion, provides a unique opportunity to study CoA cardiac remodeling. This study compares LV shape in a sample of CoA patients preand post-stent to normal patients from the CAP with the goal of developing model-based predictions of LVR to guide clinical management.

An interactive tool for rapid biventricular analysis of congenital heart disease.

SummaryCardiac malformations are the most common birth defect. Better interventions in early life have improved mortality for children with congenital heart disease, but heart failure is a significant problem in adulthood. These patients require regular imaging and analysis of biventricular (left and right ventricular) function. In this study, we describe a rapid method to analyse left and right ventricular shape and function from cardiac MRI examinations. A 4D (3D+time) finite element model template is interactively customized to the anatomy and motion of the biventricular unit. The method was validated in 17 patients and 10 ex‐vivo hearts. Interactive model updates were achieved through preconditioned conjugate gradient optimization on a multithread system, and by precomputing points predicted from a coarse mesh optimization.

Abstract 15641: Quantification of Left Ventricular Shape Differentiates Pediatric Pulmonary Hypertension Patients From Matched Controls

Background: Changes in left ventricular (LV) shape are observed in patients with pulmonary hypertension (PH). Quantification of shape changes could serve as an additional tool to non-invasively monitor pediatric patients with PH. Decomposing the shape of a ventricle into a series of components and magnitudes will facilitate differentiation of healthy and PH subjects. Methods: Parasternal short axis echo images acquired from 42 pediatric subjects with PH as well as 42 age and sex matched normal control subjects underwent speckle tracking using Velocity Vector Imaging (Siemens) to produce series of x,y coordinates tracing the LV endocardium in each frame. A Fourier transform was then used to derive shape components and magnitudes from LV shape in each frame. Magnitudes from the first 11 components were normalized to heart size (magnitude/LV length as measured on apical view) and analyzed across a single cardiac cycle. Results: Fourier decomposition produced a series of shape components from short axis echo views of the LV (Figure 1). All 11 components analyzed were significantly different between groups (Figure 2). Conclusion: Quantification of LV shape can differentiate normal pediatric subjects from those with PH. Shape analysis is a promising new method to precisely describe shape changes observed in PH. Differences between groups speak to intra ventricular coupling that occurs in right ventricular overload and may describe phenomena such as mechanical hinge points at the septal-wall interface, myocardial discontinuities or deformations from reflected pressure waves. Further analysis surrounding timing and correlation to clinical parameters is underway.

Information maximizing component analysis of left ventricular remodeling due to myocardial infarction.

BackgroundAlthough adverse left ventricular shape changes (remodeling) after myocardial infarction (MI) are predictive of morbidity and mortality, current clinical assessment is limited to simple mass and volume measures, or dimension ratios such as length to width ratio. We hypothesized that information maximizing component analysis (IMCA), a supervised feature extraction method, can provide more efficient and sensitive indices of overall remodeling.MethodsIMCA was compared to linear discriminant analysis (LDA), both supervised methods, to extract the most discriminatory global shape changes associated with remodeling after MI. Finite element shape models from 300 patients with myocardial infarction from the DETERMINE study (age 31–86, mean age 63, 20 % women) were compared with 1991 asymptomatic cases from the MESA study (age 44–84, mean age 62, 52 % women) available from the Cardiac Atlas Project. IMCA and LDA were each used to identify a single mode of global remodeling best discriminating the two groups. Logistic regression was employed to determine the association between the remodeling index and MI. Goodness-of-fit results were compared against a baseline logistic model comprising standard clinical indices.ResultsA single IMCA mode simultaneously describing end-diastolic and end-systolic shapes achieved best results (lowest Deviance, Akaike information criterion and Bayesian information criterion, and the largest area under the receiver-operating-characteristic curve). This mode provided a continuous scale where remodeling can be quantified and visualized, showing that MI patients tend to present larger size and more spherical shape, more bulging of the apex, and thinner wall thickness.ConclusionsIMCA enables better characterization of global remodeling than LDA, and can be used to quantify progression of disease and the effect of treatment. These data and results are available from the Cardiac Atlas Project (http://www.cardiacatlas.org).

IMPACTS OF ATRIALIZED RIGHT VENTRICLE AND LEFT VENTRICULAR SHAPE IN EBSTEIN’S ANOMALY ON LEFT VENTRICULAR FUNCTION ASSESSED BY CARDIOVASCULAR MAGNETIC RESONANCE

The utility of cardiovascular magnetic resonance (CMR) for assessment of patients with Ebstein’s anomaly is not well-defined. Left ventricular (LV) failure is common in Ebstein’s anomaly. We investigated whether atrialized right ventricle (ARV) and LV shape impact LV function in Ebstein’s anomaly by cardiovascular MRI (CMR). We analyzed CMR studies in patients with Ebstein’s anomaly for measures of severity, including ARV, functional (FRV) and total right ventricular (TRV) volumes, LV volumes, LV and RV ejection fraction (EF). Also, we analyzed LV wall motion and wall thickening in accordance with the 16-segment model proposed by the American Society of Echocardiography. We related those CMR values to LV failure in Ebstein’s anomaly. Ten patients (mean age 27 +/- 12 years, 80 % female) were included. ARV end-diastolic volume index (EDVi) was 91 +/- 57 ml/m2 and TRVEDVi was 232 +/- 167 ml/m2. FRVEF was 52 +/- 11 % and TRVEF was 53 +/- 16 %. LVEDVi and LVEF were normal (64 +/- 15 ml/m2 and 61 +/- 6 %) but the LV was basally narrowed and modestly dilated apically, and exhibits basal septal hypokinesis with anterior hyperkinesis. ARVEDV and TRVEDV were strongly negatively correlated with LVEDV (r = -0.72 and -0.76), and TRVEDV and TRV end-systolic volume were negatively correlated with LVEF (r = -0.53 and -0.61). LVEF was affected by atrialized and functional RV volumes. The LV was basally narrowed and modestly dilated apically, and the apparent basal septal dyskinesis observed in most patients. The ventricular interaction was indeed proved, and LV dysfunction as well as right sided volume overload has a negative impact on cardiac outcome in Ebstein’s anomaly.

Left ventricular shape and mass impact torsional dynamics in asymptomatic patients with chronic aortic regurgitation and normal left ventricular ejection fraction.

Chronic aortic regurgitation (AR) is associated with a unique pattern of left ventricular (LV) volume and pressure overload, leading to LV remodelling. LV torsional motion, a key component of LV performance, can be altered in this setting. We aimed to assess the impact of LV remodelling on LV torsional dynamics parameters using speckle-tracking echocardiography (STE) in asymptomatic AR patients. We prospectively enrolled 60 patients with chronic AR and LVEF > 50% and 55 healthy controls. LV rotation, twisting and untwisting were assessed using STE. Patients with AR had higher LV diameters, volumes and mass, a more spherical LV shape than controls, but similar LVEF. In AR patients we found reduced peak LV apical rotation and decreased (2.1 ± 0.8 vs 2.9 ± 0.9°/cm, p < 0.001) and delayed (time to peak LV twist: 0.94 ± 0.12 vs 0.99 ± 0.09, p = 0.004) peak LV torsion. Also, peak LV untwisting velocity was decreased (-123.5 ± 41.5 vs -152.3 ± 55.0°/s, p = 0.002) due to lower peak LV apical diastolic rotation rate. LV shape influenced LV torsional dynamics, a more spherical LV displaying reduced peak LV apical rotation and diastolic rotation rate and decreased LV twist. A more hypertrophied LV had a lower peak LV torsion, peak LV apical diastolic rotation rate and peak LV untwisting velocity. LV apical rotation and torsion are decreased and LV twist is delayed in patients with chronic AR and normal LVEF, detecting early subclinical LV dysfunction before LVEF declines. Also, LV untwisting is reduced in these patients. LV remodelling impairs LV torsional dynamics parameters in this setting.

A New 4D Trajectory-Based Approach Unveils Abnormal LV Revolution Dynamics in Hypertrophic Cardiomyopathy

The assessment of left ventricular shape changes during cardiac revolution may be a new step in clinical cardiology to ease early diagnosis and treatment. To quantify these changes, only point registration was adopted and neither Generalized Procrustes Analysis nor Principal Component Analysis were applied as we did previously to study a group of healthy subjects. Here, we extend to patients affected by hypertrophic cardiomyopathy the original approach and preliminarily include genotype positive/phenotype negative individuals to explore the potential that incumbent pathology might also be detected. Using 3D Speckle Tracking Echocardiography, we recorded left ventricular shape of 48 healthy subjects, 24 patients affected by hypertrophic cardiomyopathy and 3 genotype positive/phenotype negative individuals. We then applied Generalized Procrustes Analysis and Principal Component Analysis and inter-individual differences were cleaned by Parallel Transport performed on the tangent space, along the horizontal geodesic, between the per-subject consensuses and the grand mean. Endocardial and epicardial layers were evaluated separately, different from many ecocardiographic applications. Under a common Principal Component Analysis, we then evaluated left ventricle morphological changes (at both layers) explained by first Principal Component scores. Trajectories’ shape and orientation were investigated and contrasted. Logistic regression and Receiver Operating Characteristic curves were used to compare these morphometric indicators with traditional 3D Speckle Tracking Echocardiography global parameters. Geometric morphometrics indicators performed better than 3D Speckle Tracking Echocardiography global parameters in recognizing pathology both in systole and diastole. Genotype positive/phenotype negative individuals clustered with patients affected by hypertrophic cardiomyopathy during diastole, suggesting that incumbent pathology may indeed be foreseen by these methods. Left ventricle deformation in patients affected by hypertrophic cardiomyopathy compared to healthy subjects may be assessed by modern shape analysis better than by traditional 3D Speckle Tracking Echocardiography global parameters. Hypertrophic cardiomyopathy pathophysiology was unveiled in a new manner whereby also diastolic phase abnormalities are evident which is more difficult to investigate by traditional ecocardiographic techniques.

GLOBAL FEATURE FOR LEFT VENTRICULAR DYSFUNCTION DETECTION BASED ON SHAPE DEFORMATION TRACKING

Left ventricular (LV) shape alteration is closely correlated with cardiac disease and LV function. In this paper, we propose a feature to detect LV dysfunction globally by analyzing the LV shape deformation in systolic contraction. The feature is an index that is extracted from geometric measurement of LV shape such as the length of the long axis, the short axis, and the apical diameter. A framework for computing the features is also proposed that consists of shape model construction and motion estimation of myocardial boundary. The LV shape model is extracted from apical 2 and 4 chamber views of 2D echocardiography. The long axis, the short axis, and the apical diameter were redefined according to the LV shape constructed. An optical flow technique was used to estimate the position of the LV boundary in each frame. The classification of the LV dysfunction was performed using linear discriminant analysis (LDA) and neural networks (NNs). The 2D echocardiography dataset collected from routine clinical check-up were used to validate the proposed method by comparing the computation result and cardiac expert diagnose. Classification performance and statistical analysis, which was performed to discriminate between healthy and diseased data, indicated promising results. The global LV features would provide a strong basis for a global LV function diagnosis and a global cardiac pathology assessment.

Impact and Predictors of Noncircular Left Ventricular Outflow Tract Shapes on Estimating Aortic Stenosis Severity by Means of Continuity Equations

Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined. In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area. We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm(2)) was underestimated by the standard method (1.05 ± 0.47 cm(2); P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape. More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.

0523: Feasibility and accuracy of left ventricular volumes and ejection fraction measured by different echocardiographic methods in congenital heart diseases involving the right ventricle

In CHD with RV volumetric or barometric overload, LV shape is altered. Little is known about the accuracy in this population of left ventricular (LV) volumes and ejection fraction (EF) measurement by standard echocardiographic methods using geometrical assumption: Teicholz, biplane Simpson and real-time 3D echocardiography (RT-3DE). Three-dimensional knowledge-based reconstruction (3D-KR) derived from two-dimensional echocardiographic imaging is a novel technique that has no geometrical assumption. The aim of our study is to assess the accuracy of several echocardiographic methods for measuring LV volumes and EF compared to cardiac magnetic resonance (CMR) measurements (gold standard) in this population. 68 patients (mean age 13,3±4 years) with Congenital Heart Diseases (CHD) involving the RV and referred for cardiac MRI, were included. Among them, 13 patients had barometric overload, 37 patients had volumetric overload, and 18 patients had mixed overload. Echocardiographic images acquisition was performed using a standard ultrasound scanner linked to a Ventripoint Medical Systems unit. Analyzed parameters were end-diastolic volume (EDV), end-systolic volume (ESV), and LVEF measured by Teicholz, Simpson’s modified formula and RT-3DE (GE Vingmed QVG Auto-4D). The method of disks was used for CMR LV volumes. Intra-observer, inter-observer, and inter-technique variability was assessed using intraclass correlation coefficient (CC), Pearson’s CC, coefficients of variation, and Bland-Altman analysis. Feasibility was 98% for Teicholz Method and 3D-KR, 71% for Simpson’s modified formula, and 73% for RT-3DE. We found globally poor correlation and agreement for volumes and EF between the different methods and MRI. The agreement was better when RV volumes were lower than 120 ml/m2 (and thus, LV shape was less altered). LV volumes and EFs cannot be measured accurately by echocardiography in patients with dilated right ventricles.

Characterizing heart failure in the ventricular volume domain.

Heart failure (HF) may be accompanied by considerable alterations of left ventricular (LV) volume, depending on the particular phenotype. Two major types of HF have been identified, although heterogeneity within each category may be considerable. All variants of HF show substantially elevated LV filling pressures, which tend to induce changes in LV size and shape. Yet, one type of HF is characterized by near-normal values for LV end-diastolic volume (EDV) and even a smaller end-systolic volume (ESV) than in matched groups of persons without cardiac disease. Furthermore, accumulating evidence indicates that, both in terms of shape and size, in men and women, the heart reacts differently to adaptive stimuli as well as to certain pharmacological interventions. Adjustments of ESV and EDV such as in HF patients are associated with (reverse) remodeling mechanisms. Therefore, it is logical to analyze HF subtypes in a graphical representation that relates ESV to EDV. Following this route, one may expect that the two major phenotypes of HF are identified as distinct entities localized in different areas of the LV volume domain. The precise coordinates of this position imply unique characteristics in terms of the actual operating point for LV volume regulation. Evidently, ejection fraction (EF; equal to 1 minus the ratio of ESV and EDV) carries little information within the LV volume representation. Thus far, classification of HF is based on information regarding EF combined with EDV. Our analysis shows that ESV in the two HF groups follows different patterns in dependency of EDV. This observation suggests that a superior HF classification system should primarily be founded on information embodied by ESV.