Left Ventricular Shape Research Articles

Genetic basis of right and left ventricular heart shape.

Heart shape captures variation in cardiac structure beyond traditional phenotypes of mass and volume. Although observational studies have demonstrated associations with cardiometabolic risk factors and diseases, its genetic basis is less understood. We utilised cardiovascular magnetic resonance images from 45,683 UK Biobank participants to construct a heart shape atlas from bi-ventricular end-diastolic surface mesh models through principal component (PC) analysis. Genome-wide association studies were performed on the first 11 PCs that captured 83.6% of shape variance. We identified 43 significant loci, 14 were previously unreported for cardiac traits. Genetically predicted PCs were associated with cardiometabolic diseases. In particular two PCs (2 and 3) linked with more spherical ventricles being associated with increased risk of atrial fibrillation. Our study explores the genetic basis of multidimensional bi-ventricular heart shape using PCA, reporting new loci and biology, as well as polygenic risk scores for exploring genetic relationships of heart shape with cardiometabolic diseases.

Left ventricular shape index and eccentricity index with ECG-gated Nitrogen-13 ammonia PET/CT in patients with myocardial infarction, ischemia, and normal perfusion

BackgroundLV geometry with shape index (SI) and eccentricity index (EI) measured by myocardial perfusion positron emission tomography/computed tomography (PET/CT) may allow the evaluation of left ventricular (LV) adverse remodeling. This first study aims to explore the relationship of SI and EI values acquired by Nitrogen-13 ammonia PET/CT in patients with normal perfusion, ischemia, and myocardial infarction. And evaluate the correlations between the variables of LV geometry, and with the variables of LV function. Methods and resultsOne hundred and forty patients who underwent an electrocardiogram (ECG)-gated PET/CT were selected and classified into 4 groups according to ischemia or infarction burden (normal perfusion, mild ischemia, moderate-severe ischemia, and infarction). The variables were automatically retrieved using dedicated software (QPS/QGS; Cedars-Sinai, Los Angeles, CA, USA). On multicomparison analysis (one-way ANOVA and Dunnett's Test), subjects in the infarction group had significant higher values of SI end-diastolic rest (P < 0.001), and stress (P = 0.003), SI end-systolic rest (P = 0.002) and stress (P < 0.001) as well as statistically significant lower values of EI rest (P < 0.001) and stress (P < 0.001) when compared with all other groups. Regarding Pearson correlation, in the infarcted group all the variables of SI and EI were significantly correlated (P < 0.001) with strong correlation coefficients (>0.60). SI end-systolic correlated significantly with the variables of LV function independently of the group of patients (P < 0.05). ConclusionsShape and eccentricity indices differ in patients with myocardial infarction as compared to patients with ischemia or normal perfusion. This encourage further research in their potential for detecting LV adverse remodeling.

Timing of Surgery for Asymptomatic Primary Mitral Regurgitation: Possible Value of Early, Serial Measurements of Left Ventricular Sphericity.

Asymptomatic primary mitral regurgitation due to myxomatous degeneration of the mitral valve leaflets may remain so for long periods, even as left ventricular function progresses to a decompensated stage. During the early compensated stage, the ventricle's initial response to the volume overload is an asymmetric increase in the diastolic short axis dimension, accomplished by a diastolic shift of the interventricular septum into the right ventricular cavity, creating a more spherical left ventricular diastolic shape, increasing diastolic filling and stroke volume. Early valve repair is recommended to reduce postoperative left ventricular dysfunction. Early serial measurements of left ventricular sphericity index [LV-Si]. during the compensated stage of mitral regurgitation might identify subtle changes in left ventricular shape and assist in determining the optimal earliest timing for surgical intervention.

Do False Tendons Prevent Adverse Left Ventricular Remodeling After Anterior Wall Myocardial Infarction? An Echocardiographic Strain Imaging Study

The role of muscular left ventricular (LV) false tendons (FTs) is poorly understood. To gain insight into their pathophysiologic significance, we adapted echocardiographic LV strain imaging software to measure LVFT longitudinal strain in subjects with normal left ventricles and in patients who sustained previous anterior wall myocardial infarction (AWMI). GE EchoPAC software was used to measure longitudinal strain in LVFTs ≥0.3 cm in diameter. Tendinous strain was measured in 11 patients with LVFTs confined to the left anterior descending artery territory (connecting the anteroseptum or anterior wall to the apex) ≥6 months after AWMI (myocardial infarction [MI]+FT+ group) and in 25 patients with normal hearts containing LVFTs (MI-FT+ group). We also compared the indexed LV end-diastolic volumes in the MI+FT+ group to that of 25 patients with previous AWMI without LVFTs (MI+FT- group). The mean LVFT strain in MI+FT+ group was 5.5 ± 6.2% and -28.9 ± 4.7% in the MI-FT+ group (p <0.0001). The indexed LV end-diastolic volume in the MI+FT+ group did not differ from the MI+FT- group (88.4 ± 17.8 vs 87.9 ± 17 ml/m2, p = 0.90). In conclusion, the negative strain (contraction) developed by LVFTs in the MI-FT+ group may help maintain normal LV size and shape by generating inward restraining forces. The development of positive strain (stretch) in LVFTs in patients in the MI+FT+ group suggests they become infarcted after AWMI. This implies that they are incapable of generating inward restraining forces that might otherwise mitigate adverse remodeling. Of note, LV volumes after AWMI do not differ whether or not LVFTs are present.

Assessment of LV structural remodelling by the application of the finite element method to 3D echocardiography data

ABSTRACT This study presents novel applications for conducting left ventricular (LV) shape analysis within a finite element (FE) framework. The 3D endocardial surface data of both healthy and dilated LVs are obtained using TomTec 4D LV-Analysis software through echocardiography and then imported into the FE framework for LV geometry. By applying FE analysis to 3D echocardiography data, we propose novel methods for evaluating LV shape and remodelling, including the nodal strain approximation along myocardial fibre directions, the assessment of LV sphericity and eccentricity in multiple planes, a new method for LV apical conicity, and the analysis of regional LV rotations. The feasibility of these novel formulations and the developed FE based framework are demonstrated by evaluating and comparing 3D echocardiography data from two objects, one with a healthy LV and the other with dilated cardiomyopathy.

Antagonism of contractile forces in left ventricular hypertrophy: a diagnostic challenge for better pathophysiological and clinical understanding

Cardiac function is characterised by haemodynamic parameters in the clinical scenario. Due to recent development in imaging techniques, the clinicians focus on the quantitative assessment of left ventricular size, shape...

Early-Onset Fetal Growth Restriction Increases Left Ventricular Sphericity in Adolescents Born Very Preterm.

Left ventricular shape alterations predict cardiovascular outcomes and have been observed in children born preterm and after fetal growth restriction (FGR). The aim was to investigate whether left ventricular shape is altered in adolescents born very preterm and if FGR has an additive effect. Adolescents born very preterm due to verified early-onset FGR and two control groups with birthweight appropriate for gestational age (AGA), born at similar gestational age and at term, respectively, underwent cardiac MRI. Principal component analysis was applied to find the modes of variation best explaining shape variability for end-diastole, end-systole, and for the combination of both, the latter indicative of function. Seventy adolescents were included (13-16years; 49% males). Sphericity was increased for preterm FGR versus term AGA for end-diastole (36[0-60] vs -42[-82-8]; p = 0.01) and the combined analysis (27[-23-94] vs -51[-119-11]; p = 0.01), as well as for preterm AGA versus term AGA for end-diastole (30[-56-115] vs -42[-82-8]; p = 0.04), for end-systole (57[-29-89] vs -30[-79-34]; p = 0.03), and the combined analysis (44[-50-145] vs -51[-119-11]; p = 0.02). No group differences were observed for left ventricular mass or ejection fraction (all p ≥ 0.33). Sphericity was increased after very preterm birth and exacerbated by early-onset FGR, indicating an additive effect to that of very preterm birth on left ventricular remodeling. Increased sphericity may be a prognostic biomarker of future cardiovascular disease in this cohort that as of yetshows no signs of cardiac dysfunction using standard clinical measurements.

Cardiac phenotype of propionic acidemia in the Amysh community

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Propionic acidemia (PA) is an organic acid disorder with poorly described cardiac phenotype despite progressive important cardiac remodeling and causes of death including congestive heart failure and sudden cardiac death, often in a setting of vigorous exercise or stress. Cardiac modifications begin at cellular level, both metabolic and lipid depositions, resulting in overall changes in shape, size, geometry and function, with ventricular dysfunction and risk for arrhythmias at young age. Purpose Echocardiographic assessment of left ventricular (LV) shape and timing (especially the Isovolumic contraction time (IVCT)) can help us understand the pathophysiology during the remodeling process in this rare disease. Methods We included all the PA patients from the Amish plain Community seen in our center. Clinical data, including demographics, ECG and echo measurements were recorded. Results We included 22 patients, who were homozygous for the pathogenic variant for PA, (59% males, 20.3± 13.3 years old). ECG analysis showed mild tachycardia (92 ± 30bpm) with normal QRS (84± 18 msec) and QTc segments duration (424± 31 msec). Echocardiography demonstrated a globular LV with dilated base and apical segments, normal systolic function, and normal diastolic function. The Global Longitudinal Strain was mildly decreased (GLS −17±3.08) with a dispersion of the regional strain with apical sparing. (Figure 1). The mean LV IVCT (75 msec) was longer compared to mean RV IVCT (69 msec, Figure 1). Conclusion Patients with PA present with very specific remodeling, including an increase in sphericity of the heart and slightly decreased GLS with normal EF. The very long LV IVCT suggests a problem with pressure generation, potentially as a marker of decreased LV contractility, either at cellular level or with activation-contraction coupling. Together with the difference in timings between the LV and RV this might become a substrate for life-threatening arrhythmias. A contractility problem, together with the exercise induced arrhythmias suggest that PA patients might benefit from afterload reduction.

Left ventricular shape index and eccentricity index assessed by gated PET/CT. Promising parameters for detection of left ventricular remodelling

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): University of Groningen/University Medical Center Groningen. Background Left ventricular (LV) remodelling has been described as the pathway that precedes heart failure. This process consists of changes in the shape, size, volume and function of the left ventricle; all of this directly associated to increased risk of major adverse cardiac events (MACEs). Different parameters are used to evaluate cardiac geometry in multiple cardiac imaging modalities. In nuclear medicine, LV geometry can be studied through shape index (SI) and eccentricity index (EI). These values examine the degree of sphericity (SI) and elongation (EI) of the left ventricle. However, in cardiac perfusion PET/CT, the LV remodelling has not been extensively studied with SI and EI values, and their role is yet to be elucidated. Purpose This project aim to describe the role of SI and EI values in patients examined by gated 13N-ammonia PET/CT in ischemic and infarction scenario. Methods We retrospectively randomly selected 140 patients referred to 13N-ammonia PET/CT between 2016 and 2022 for suspected or diagnosed CAD. The patients were classified in 4 groups of 35 patients according to the presence and burden of ischemia or infarction: normal=0% of scar burden and ischemic burden; mild ischemia=5–10% of ischemic burden; moderate-severe ischemia≥10% of ischemic burden and infarction≥5% of scar burden. We collected the information regarding myocardial flows (myocardial blood flow (MBF) at rest, hyperaemic MBF at stress and coronary flow reserve (CFR)) and left ventricular geometry (SI end-diastolic at rest and stress, SI end-systolic at rest and stress, and EI at rest and stress). All the variables were automatically processed with QPS/QGS software. We performed a multicomparison analysis for the mentioned variables with One way ANOVA variance and Dunnett’s Test as Post Hoc, stablishing as the control the infarction group. Results The study population consisted of 35.7% women, all patients over 36 years old, with no significant differences between groups regarding the presence of cardiac risk factors. The control group showed important changes in all SI and EI when compared to the rest of the groups. With a maximum change of 0.090 observed in SI end-systolic stress in the mild ischemia group, and a minimum change of −0.041 in EI rest in the moderate-severe ischemia group. Control subjects had statistically significant higher values of SI end-diastolic rest (p&amp;lt;0.001) and stress (p = 0.005), end-systolic rest (p = 0.001)and stress (p&amp;lt;0.001) and statistically significant lower values of EI rest (p&amp;lt;0.001) and stress (p&amp;lt;0.001) when compared with all the other groups. Additionally, all SI and EI values in stress follow a linear change proportional to the degree of myocardial extend (Figure 1 and 2). Conclusions(s) SI and EI by 13N-ammonia PET/CT are variables that seem clinically relevant for the early detection of LV remodeling. However, there is still research to do for establishing cut-off values and evaluating the prediction of MACEs.

Left ventricular shape remodelling predicts major arrhythmic events in stable coronary artery disease

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): This work was supported by the National Institute for Health Research Biomedical Research Centre at Guy’s and St. Thomas’ Trust and King’s College, the Centre of Excellence in Medical Engineering funded by the Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC; WT088641/Z/09/Z). M.J.B. is supported by a Medical Research Council New Investigator Grant (MR/N011007/1) and British Heart Foundation (Project grant PG/18/74/34077). This work was supported by EPSRC 2018/19 DTP - EP/R513064/1 grant. This work was supported by a National Heart and Lung Institute Foundation grant awarded to Professor Sanjay Prasad and Dr Richard Jones. Background Arrhythmic risk stratification of patients with stable coronary artery disease (CAD) for defibrillator implantation remains imprecise. Current clinical guidelines center on a basic assessment of adverse cardiac remodelling, an approach with well documented limitations. More advanced analysis of intricate and regional LV remodelling in these patients may shed new insight for enhanced risk prediction of life-threatening arrhythmia in stable CAD. Objective We explored a novel computational 3D LV shape analysis strategy to accurately represent, and quantify, arrhythmogenic LV remodelling patterns in late gadolinium enhancement cardiovascular magnetic resonance images (LGE-CMR) in patients with stable CAD. We assess the utility of our patient-specific 3D LV arrhythmic shape (LVAS) score predicting major arrhythmic event; comparing to the current clinical benchmark of severely reduced LVEF and NYHA functional class. Methods Patients with stable CAD were prospectively recruited into a CMR registry and followed up for a composite endpoint of major arrhythmic events (MAE) consisting of sudden cardiac death (SCD), aborted SCD or haemodynamically unstable VT. Time-to-event data was also recorded. 2D LGE-CMR images were contoured and used as input to an advanced computational shape-analysis approach (Figure 1A). Reconstructed 3D LV shape models were analysed using Principle Component Analysis and Cox-Lasso to characterise the average arrhythmogenic LV shape, which was then used to quantitatively define a patient-specific LV arrhythmic shape (LVAS) score. Results Of 397 patients (mean [SD] LVEF% 45.4 ± 16.0) followed for a median (IQR) of 6 (3) years, 55 (14%) experienced a major arrhythmic event (MAE). The mean (SD) LVEF for patients who experienced MAE was lower than for those that did not (37.1% ± 13.2 vs 46.7% ± 16.0), yet there was no difference in NYHA class. LVAS mean (95% confidence interval [CI]) score was different between event and event-free patients: 2.98 (0.48-6.44) vs 19.83 (10.66-29), P&amp;lt;0.001. On univariate Cox regression analysis both LVAS score (hazard ratio [HR] 2.1, 95% CI 1.6-2.7, P&amp;lt;0.001) and LVEF&amp;lt;35% (HR 2.9, 95% CI 1.6-5.0, P&amp;lt;0.01) were associated with the primary endpoint. NYHA Class &amp;gt;I was not associated with the primary endpoint (HR 1.5, 95% CI 0.8-2.7, P=0.221). In multivariate Cox regression analysis, LVAS remained independently associated with the primary endpoint after adjusting for LVEF&amp;lt;35% and NYHA&amp;gt;Class I: LVAS score HR 2.1, 95% CI 1.5-3.0, P&amp;lt;0.001; LVEF&amp;lt;35% HR 1.0, 95% CI 0.5-2.2, P=0.923; NYHA&amp;gt;Class I HR 1.3, 95% CI 0.7-2.5, P=0.443 (Figure 1 B, C). The addition of the LVAS score increased the C-statistic from 0.6 to 0.75 between models. Conclusion A Left Ventricle Arrhythmic Shape score improved arrhythmic risk stratification compared to guideline-based clinical parameters, highlighting a potentially novel approach to identifying candidates for implantable cardioverter defibrillators in stable CAD.

MRXCAT2.0: Synthesis of realistic numerical phantoms by combining left-ventricular shape learning, biophysical simulations and tissue texture generation

BackgroundStandardised performance assessment of image acquisition, reconstruction and processing methods is limited by the absence of images paired with ground truth reference values. To this end, we propose MRXCAT2.0 to generate synthetic data, covering healthy and pathological function, using a biophysical model. We exemplify the approach by generating cardiovascular magnetic resonance (CMR) images of healthy, infarcted, dilated and hypertrophic left-ventricular (LV) function. MethodIn MRXCAT2.0, the XCAT torso phantom is coupled with a statistical shape model, describing population (patho)physiological variability, and a biophysical model, providing known and detailed functional ground truth of LV morphology and function. CMR balanced steady-state free precession images are generated using MRXCAT2.0 while realistic image appearance is ensured by assigning texturized tissue properties to the phantom labels. FindingPaired CMR image and ground truth data of LV function were generated with a range of LV masses (85–140 g), ejection fractions (34–51%) and peak radial and circumferential strains (0.45 to 0.95 and − 0.18 to − 0.13, respectively). These ranges cover healthy and pathological cases, including infarction, dilated and hypertrophic cardiomyopathy. The generation of the anatomy takes a few seconds and it improves on current state-of-the-art models where the pathological representation is not explicitly addressed. For the full simulation framework, the biophysical models require approximately two hours, while image generation requires a few minutes per slice. ConclusionMRXCAT2.0 offers synthesis of realistic images embedding population-based anatomical and functional variability and associated ground truth parameters to facilitate a standardized assessment of CMR acquisition, reconstruction and processing methods.

Left Ventricular Adverse Remodeling in Ischemic Heart Disease: Emerging Cardiac Magnetic Resonance Imaging Biomarkers

Post-ischemic left ventricular (LV) remodeling is a biologically complex process involving myocardial structure, LV shape, and function, beginning early after myocardial infarction (MI) and lasting until 1 year. Adverse remodeling is a post-MI maladaptive process that has been associated with long-term poor clinical outcomes. Cardiac Magnetic Resonance (CMR) is the best tool to define adverse remodeling because of its ability to accurately measure LV end-diastolic and end-systolic volumes and their variation over time and to characterize the underlying myocardial changes. Therefore, CMR is the gold standard method to assess in vivo myocardial infarction extension and to detect the presence of microvascular obstruction and intramyocardial hemorrhage, both associated with adverse remodeling. In recent times, new CMR quantitative biomarkers emerged as predictive of post-ischemic adverse remodeling, such as T1 mapping, myocardial strain, and 4D flow. Additionally, CMR T1 mapping imaging may depict infarcted tissue and assess diffuse myocardial fibrosis by using surrogate markers such as extracellular volume fraction, which may predict functional recovery or risk stratification of remodeling. Finally, there is emerging evidence supporting the utility of intracavitary blood flow kinetic energy and hemodynamic features assessed by the 4D flow CMR technique as early predictors of remodeling.

Left ventricular anatomy in obstructive hypertrophic cardiomyopathy: beyond basal septal hypertrophy.

Obstructive hypertrophic cardiomyopathy (oHCM) is characterized by dynamic obstruction of the left ventricular (LV) outflow tract (LVOT). Although this may be mediated by interplay between the hypertrophied septal wall, systolic anterior motion of the mitral valve, and papillary muscle abnormalities, the mechanistic role of LV shape is still not fully understood. This study sought to identify the LV end-diastolic morphology underpinning oHCM. Cardiovascular magnetic resonance images from 2398 HCM individuals were obtained as part of the NHLBI HCM Registry. Three-dimensional LV models were constructed and used, together with a principal component analysis, to build a statistical shape model capturing shape variations. A set of linear discriminant axes were built to define and quantify (Z-scores) the characteristic LV morphology associated with LVOT obstruction (LVOTO) under different physiological conditions and the relationship between LV phenotype and genotype. The LV remodelling pattern in oHCM consisted not only of basal septal hypertrophy but a combination with LV lengthening, apical dilatation, and LVOT inward remodelling. Salient differences were observed between obstructive cases at rest and stress. Genotype negative cases showed a tendency towards more obstructive phenotypes both at rest and stress. LV anatomy underpinning oHCM consists of basal septal hypertrophy, apical dilatation, LV lengthening, and LVOT inward remodelling. Differences between oHCM cases at rest and stress, as well as the relationship between LV phenotype and genotype, suggest different mechanisms for LVOTO. Proposed Z-scores render an opportunity of redefining management strategies based on the relationship between LV anatomy and LVOTO.

Analysing functional implications of differences in left ventricular morphology using statistical shape modelling

Functional implications of left ventricular (LV) morphological characterization in congenital heart disease are not widely explored. This study qualitatively and quantitatively assessed LV shape associations with a) LV function and b) thoracic aortic morphology in patients with aortic coarctation (CoA) with/without bicuspid aortic valve (BAV), and healthy controls. A statistical shape modelling framework was employed to analyse three-dimensional (3D) LV shapes from cardiac magnetic resonance (CMR) data in isolated CoA (n = 25), CoA + BAV (n = 30), isolated BAV (n = 30), and healthy controls (n = 25). Average 3D templates and deformations were computed. Correlations between shape data and CMR-derived morphometric parameters (i.e., sphericity, conicity) or global and apical strain values were assessed to elucidate possible functional implications. The relationship between LV shape features and arch architecture was also explored. The LV template was shorter and more spherical in CoA patients. Sphericity was overall associated with global and apical radial (p = 0.001, R2 = 0.09; p < 0.0001, R2 = 0.17) and circumferential strain (p = 0.001, R2 = 0.10; p = 0.04, R2 = 0.04), irrespective of the presence of aortic stenosis and/or regurgitation and controlling for age and hypertension status. LV strain was not associated with arch architecture. Differences in LV morphology were observed between CoA and BAV patients. Increasing LV sphericity was associated with reduced strain, independent of aortic arch architecture and functional aortic valve disease.

Left ventricular morphology in patients with aortic coarctation and bicuspid aortic valve: novel insights from a statistical shape modelling framework

Abstract Background The functional implications of left ventricular (LV) morphological characterization in congenital heart disease (CHD) are not widely explored. Purpose This study qualitatively and quantitatively assessed LV shape associations with a) LV function and b) thoracic aortic morphology in patients with aortic coarctation (CoA) with/without bicuspid aortic valve (BAV). Methods A statistical shape modelling (SSM) framework was employed to analyse three-dimensional (3D) LV shapes from cardiac magnetic resonance (CMR) imaging data in n=110 cases including: isolated CoA (n=25), CoA+BAV (n=30), isolated BAV (n=30), and age-matched healthy controls (n=25). Average 3D templates (Picture 1) and deformations were computed. Correlations between shape data and CMR-derived morphometric parameters (i.e. sphericity, conicity) as well as CMR-derived global and apical strain values were assessed to elucidate possible functional implications. The relationship between LV shape features and arch architecture (i.e. gothicity, tortuosity) was also explored by means of regression analysis. Results The LV template was shorter and more spherical in CoA patient (Picture 1), as also confirmed by statistical analysis of the SSM-derived shape modes. LV sphericity, which was higher in CoA, was associated (p≤0.04) with lower global longitudinal, radial and circumferential strain, irrespective of the presence of aortic stenosis and/or regurgitation. Conversely, neither LV morphology nor LV strain was not associated with arch architecture. Conclusions Differences in LV morphology were observed between CoA and BAV patients. Increasing LV sphericity was associated with reduced strain, independent of aortic arch architecture and functional aortic valve disease. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation and NIHR BRC

Multi-Ethnic Study of Atherosclerosis: Relationship between Left Ventricular Shape at Cardiac MRI and 10-year Outcomes.

Background Left ventricular (LV) subclinical remodeling is associated with adverse outcomes and indicates mechanisms of disease development. Standard metrics such as LV mass and volumes may not capture the full range of remodeling. Purpose To quantify the relationship between LV three-dimensional shape at MRI and incident cardiovascular events over 10 years. Materials and Methods In this retrospective study, 5098 participants from the Multi-Ethnic Study of Atherosclerosis who were free of clinical cardiovascular disease underwent cardiac MRI from 2000 to 2002. LV shape models were automatically generated using a machine learning workflow. Event-specific remodeling signatures were computed using partial least squares regression, and random survival forests were used to determine which features were most associated with incident heart failure (HF), coronary heart disease (CHD), and cardiovascular disease (CVD) events over a 10-year follow-up period. The discrimination improvement of adding LV shape to traditional cardiovascular risk factors, coronary artery calcium scores, and N-terminal pro-brain natriuretic peptide levels was assessed using the index of prediction accuracy and time-dependent area under the receiver operating characteristic curve (AUC). Kaplan-Meier survival curves were used to illustrate the ability of remodeling signatures to predict the end points. Results Overall, 4618 participants had sufficient three-dimensional MRI information to generate patient-specific LV models (mean age, 60.6 years ± 9.9 [SD]; 2540 women). Among these participants, 147 had HF, 317 had CHD, and 455 had CVD events. The addition of LV remodeling signatures to traditional cardiovascular risk factors improved the mean AUC for 10-year survival prediction and achieved better performance than LV mass and volumes; HF (AUC, 0.83 ± 0.01 and 0.81 ± 0.01, respectively; P < .05), CHD (AUC, 0.77 ± 0.01 and 0.75 ± 0.01, respectively; P < .05), and CVD (AUC, 0.78 ± 0.0 and 0.76 ± 0.0, respectively; P < .05). Kaplan-Meier analysis demonstrated that participants with high-risk HF remodeling signatures had a 10-year survival rate of 56% compared with 95% for those with low-risk scores. Conclusion Left ventricular event-specific remodeling signatures were more predictive of heart failure, coronary heart disease, and cardiovascular disease events over 10 years than standard mass and volume measures and enable an automatic personalized medicine approach to tracking remodeling. © RSNA, 2022 Online supplemental material is available for this article.

Leveraging CMR for 3D echocardiography: an annotated multimodality dataset for AI

Abstract Funding Acknowledgements: Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Health Research Council of New Zealand (HRC) National Heart Foundation of New Zealand (NHF) Segmentation of the left ventricular myocardium and cavity in 3D echocardiography (3DE) is a critical task for the quantification of systolic function in heart disease. Continuing advances in 3DE have considerably improved image quality, prompting increased clinical uptake in recent years, particularly for volumetric measurements. Nevertheless, analysis of 3DE remains a difficult problem due to inherently complex noise characteristics, anisotropic image resolution, and regions of acoustic dropout. One of the primary challenges associated with the development of automated methods for 3DE analysis is the requirement of a sufficiently large training dataset. Historically, ground truth annotations have been difficult to obtain due to the high degree of inter- and intra-observer variability associated with manual 3DE segmentation, thus, limiting the scope of AI-based solutions. To address the lack of expert consensus, we instead used labels derived from cardiac magnetic resonance (CMR) images of the same subjects. By spatiotemporally registering CMR labels to corresponding 3DE image data on a per subject basis (Figure 1), we collated 520 annotated 3DE images from a mixed cohort of 130 human subjects (2 independent single-beat acquisitions per subject at end-diastole and end-systole) consisting of healthy controls and patients with acquired cardiac disease. Comprising images acquired across a range of patient demographics, this curated dataset exhibits variation in image quality, 3DE acquisition parameters, as well as left ventricular shape and pose within the 3D image volume. To demonstrate the utility of such a dataset, nn-UNet, a self-configuring deep learning method for semantic segmentation was employed. An 80/20 split of the dataset was used for training and testing, respectively, and data augmentations were applied in the form of scaling, rotation, and reflection. The trained network was capable of reproducing measurements derived from CMR for end-diastolic volume, end-systolic volume, ejection fraction, and mass, while outperforming an expert human observer in terms of accuracy as well as scan-rescan reproducibility (Table I). As part of ongoing efforts to improve the accuracy and efficiency of 3DE analysis, we have leveraged the high resolution and signal-to-noise-ratio of CMR (relative to 3DE), to create a novel, publicly available benchmark dataset for developing and evaluating 3DE labelling methods. This approach not only significantly reduces the effects of observer-specific bias and variability in training data arising from conventional manual 3DE analysis methods, but also improves the agreement between cardiac indices derived from 3DE and CMR. Figure 1. Data annotation workflow Table I. Results

Incremental value of left ventricular shape parameters measured by gated SPECT MPI in predicting the super-response to CRT

BackgroundThe purpose of this study was to evaluate the predictive value of left ventricular (LV) shape parameters measured by gated SPECT myocardial perfusion imaging (MPI) in super-responders enrolled in the VISION-CRT trial. MethodsOne hundred and ninety-nine patients who met standard criteria for CRT from multiple centers were enrolled in this study. End-systolic eccentricity (ESE) and end-diastolic eccentricity (EDE) were measures of LV shape. Super-responders were the patients who had a relative increase in left ventricular ejection fraction (LVEF) ≥ 15%. ResultsComplete data were obtained in 165 patients, and 43.6% of them were classified as super-responders. ESE was an independent predictor of CRT super-responders in univariate (OR 12.59, 95% CI 1.56–101.35, P = .017) and multivariate analysis (OR 35.71, 95% CI 1.66–766.03, P = .006). ESE had an incremental value over significant clinical and SPECT imaging variables, including angiotensin-converting enzyme inhibitors or angiotensin II receptor blocker, coronary artery disease, myocardial infarction, LVEF, end-diastolic volume index, and scar burden (AUC 0.82 vs. 0.80, sensitivity 0.68 vs. 0.65, specificity 0.82 vs. 0.78). ConclusionsLV shape parameters derived from gated SPECT MPI have the promise to improve the prediction of the super-response to CRT. Moreover, ESE provides incremental value over existing clinical and nuclear imaging variables.

Cardiac remodelling in association with left ventricular dyssynchrony and systolic dysfunction in patients with coronary artery disease.

In patients with coronary artery disease (CAD), ischaemic cardiomyopathy may result in progressive cardiac remodelling and left ventricular (LV) dysfunction. Myocardial perfusion imaging (MPI) can be used to quantify LV size and shape, mechanical dyssynchrony (LVMD) and ejection fraction (EF) as well as myocardial ischaemia and injury extents. We investigated the prevalence of LV remodelling (LVR) in patients with CAD and the relationship between LVR, LVMD and EF. Three hundred twenty-sixpatients with CAD were evaluated. The EF and end-diastolic volume (EDV) were measured using MPI. LVMD was assessed using phase analysis. LVR was characterised according to LV dilatation or increased shape indices (systolic shape index[SIES] anddiastolic shape index [SIED]). LVR were observed in 41% of CAD patients. EDV, SIES and SIED were larger in patients with LVMD or low EF. After adjustment for age, sex and infarct and ischaemia extents, phase histogram bandwidth correlated with EDV (r = 0.218) and SIES (r = 0.266) and EF correlated with EDV (r = -0.535), SIES (r = -0.554) and SIED (r = -0.217, p < 0.001 for all). LVR is frequently seen in patients with CAD and may be detected even before the development of symptomatic heart failure. A large LV volume and a more spherical-shaped LV were associated with LVMD and low EF, highlighting the close relationships between remodelling and systolic dyssynchrony and dysfunction. MPI is useful for assessing LVR by providing information about LV size and shape, which changes from an ellipsoid towards a spherical form in the development of ischaemic cardiomyopathy.

Reshaping the Preterm Heart: Shifting Cardiac Renin-Angiotensin System Towards Cardioprotection in Rats Exposed to Neonatal High-Oxygen Stress.

Background:Approximately 10% of infants are born preterm. Preterm birth leads to short and long-term changes in cardiac shape and function. By using a rat model of neonatal high-oxygen (80%O2) exposure, mimicking the premature hyperoxic transition to the extrauterine environment, we revealed a major role of the renin-angiotensin system peptide Angio II (angiotensin II) and its receptor AT1 (angiotensin receptor type 1) on neonatal O2-induced cardiomyopathy. Here, we tested whether treatment with either orally active compounds of the peptides Angio-(1–7) or alamandine included in cyclodextrin could prevent postnatal cardiac remodeling and the programming of cardiomyopathy induced by neonatal high-O2 exposure.Methods:Sprague-Dawley pups were exposed to room air or 80% O2 from postnatal day 3 (P3) to P10. Neonatal rats were treated orally from P3 to P10 and assessed at P10 and P28. Left ventricular (LV) shapes were characterized by tridimensional computational atlases of ultrasound images in addition to histomorphometry.Results:At P10, high O2-exposed rats presented a smaller, globular and hypertrophied LV shape versus controls. Treatment with cyclodextrin–Angio-(1–7) significantly improved LV function in the O2-exposed neonatal rats and slightly changed LV shape. Cyclodextrin-alamandine and cyclodextrin–Angio-(1–7) treatments similarly reduced hypertrophy at P10 as well as LV remodeling and dysfunction at P28. Both treatments upregulated cardiac angiotensin-converting enzyme 2 in O2-exposed rats at P10 and P28.Conclusions:Our findings demonstrate LV remodeling changes induced by O2-stress and the potential benefits of treatments targeting the cardioprotective renin-angiotensin system axis, supporting the neonatal period as an important window for interventions aiming at preventing cardiomyopathy in people born preterm.