Left Ventricle Length Research Articles

Development of automated neural network prediction for echocardiographic left ventricular ejection fraction.

The echocardiographic measurement of left ventricular ejection fraction (LVEF) is fundamental to the diagnosis and classification of patients with heart failure (HF). This paper aimed to quantify LVEF automatically and accurately with the proposed pipeline method based on deep neural networks and ensemble learning. Within the pipeline, an Atrous Convolutional Neural Network (ACNN) was first trained to segment the left ventricle (LV), before employing the area-length formulation based on the ellipsoid single-plane model to calculate LVEF values. This formulation required inputs of LV area, derived from segmentation using an improved Jeffrey's method, as well as LV length, derived from a novel ensemble learning model. To further improve the pipeline's accuracy, an automated peak detection algorithm was used to identify end-diastolic and end-systolic frames, avoiding issues with human error. Subsequently, single-beat LVEF values were averaged across all cardiac cycles to obtain the final LVEF. This method was developed and internally validated in an open-source dataset containing 10,030 echocardiograms. The Pearson's correlation coefficient was 0.83 for LVEF prediction compared to expert human analysis (p < 0.001), with a subsequent area under the receiver operator curve (AUROC) of 0.98 (95% confidence interval 0.97 to 0.99) for categorisation of HF with reduced ejection (HFrEF; LVEF<40%). In an external dataset with 200 echocardiograms, this method achieved an AUC of 0.90 (95% confidence interval 0.88 to 0.91) for HFrEF assessment. The automated neural network-based calculation of LVEF is comparable to expert clinicians performing time-consuming, frame-by-frame manual evaluations of cardiac systolic function.

Association of Gestational Age at Birth With Left Cardiac Dimensions at Near-Term Corrected Age Among Extremely Preterm Infants

Remodeling and altered ventricular geometry have been described in adults born preterm. Although they seem to have an adverse cardiac phenotype, the impact of various degrees of prematurity on cardiac development has been scarcely reported. In this study, we evaluated the impact of gestational age (GA) at birth on cardiac dimensions and function at near-term age among extremely preterm infants. This is a retrospective single-center cohort study of infants born at <29weeks ofGA between 2015 and 2019. Infants with available clinically acquired echocardiography between 34 and 43weeks were included. Two groups were investigated: those born <26weeks and those born ≥26weeks. All measurements were done by an expert masked to clinical data using the raw images. The primary outcome was measurements of cardiac dimensions and function based on GA group. Secondary outcomes were the association between cardiac dimensions and postnatal steroid exposure and with increments of GA at birth. A total of 205 infants were included (<26weeks, n=102; ≥26weeks, n=103). At time of echocardiography, weight (2.4±0.5 vs 2.5±0.5kg, P=.86) and age (37.2±1.6 vs 37.1±1.9weeks, P=.74) were similar between groups. There was no difference in metrics of right-sided dimensions and function. However, left-sided dimensions were decreased in infants born <26weeks, including systolic left ventricle (LV) diameter (1.06±0.20cm vs 1.12±0.18cm, P=.02), diastolic LV length (2.85±0.37 vs 3.02±0.57cm, P=.02), and estimated LV end-diastolic volume (5.36±1.69 vs 6.01±1.79mL, P=.02). In our cohort of very immature infants, birth at the extreme of prematurity was associated with smaller left cardiac dimensions around 36weeks of corrected age. Future longitudinal prospective studies should evaluate further the impact of prematurity on LV development and performance and their long-term clinical impact.

Echocardiographic Measures of Left Atrial Structure and Function and the Association with Atrial Fibrillation following Acute Coronary Syndrome

Introduction: Acute coronary syndrome (ACS) is associated with an increased risk of developing atrial fibrillation (AF). This arrhythmia is associated with adverse outcomes, making it important to identify high-risk patients. The aim was to evaluate the prognostic value of measures of left atrial (LA) structure and function in AF prediction following ACS. Methods: Three hundred and eighty-one patients who had a percutaneous coronary intervention for ACS were included in the study. Our endpoint was new-onset AF. Results: With a median follow-up time of 5.4 [3.9–6.8] years, 56 patients (14.7%) developed AF. Patients developing AF had significantly (p ≤ 0.05) increased maximal and minimal LA volumes (LAV_max and LAV_min, respectively). LAV_max and LAV_min remained significantly increased in AF patients when indexing to either body surface area (LAV_max/BSA and LAV_min/BSA, respectively), left ventricle length in end diastole (LAV_max/LVLd and LAV_min/LVLd, respectively), or late mitral annular diastolic velocity (LAV_max/a’ and LAV_min/a’, respectively), while LA expansion index (LAEi), LA emptying fraction (LAEF), and peak LA longitudinal strain (PALS) were decreased. In univariable Cox regressions, all LA measures were found to be predictors of AF. After multivariable adjustment for clinical and echocardiographic parameters, all measures reflecting atrial function (LAV_min, LAV_min/BSA, LAV_min/LVLd, LAV_min/a’, LAV_max/a’, LAEF, LAEi, and PALS) (p ≤ 0.05) but no structural measures (LAV_max, LAV_max/BSA, and LAV_max/LVLd) remained significant independent predictors of AF. Conclusion: Echocardiographic measures of LA function are independent predictors of AF following ACS. Evaluation of LA function might improve the prognostic workup, aid in risk stratification for AF, and improve selection for further examinations.

Expected small left heart size in the presence of congenital diaphragmatic hernia: Fetal values and Z-scores for infants confirmed to have no heart disease postnatally.

In fetuses with left-sided congenital diaphragmatic hernia (CDH), left heart structures may appear small, but usually normalize after birth in the absence of structural cardiac anomalies. To decrease the possibility of an erroneous diagnosis of structural heart disease, we identify normal values for left heart structures in the presence of left CDH and secondarily investigate the relationship of left heart size and survival to neonatal hospital discharge. Left heart structures [mitral valve (MV) and aortic valve (AoV) annulus diameter, left ventricle (LV) length and width] were measured by fetal echocardiogram in fetuses with left CDH and no congenital heart disease. We generated linear regression models to establish the relationship of gestational age for each left heart structure using data from fetuses who survived after birth. We calculated z-scores (normalized to gestational age), and assessed the relationship of survival to the size of each structure. One hundred forty-two fetuses underwent fetal echocardiogram (median 25 weeks' gestation, IQR 23, 27 weeks). Left heart structures were deemed small when using published normative data from unaffected fetuses (z-scores: MV -1.09 ± 1.35, AoV -2.12 ± 1.16, LV length -1.36 ± 1.24, LV width -4.79 ± 0.79). CDH-specific models derived from log-transformed values yielded left-shifted distributions, reflecting the small structures (mean z-score lower by: MV 0.99 ± 0.30, AoV 2.04 ± 0.38, LV length 1.30 ± 0.36, and LV width 4.69 ± 0.28; p < 0.0001 for all comparisons). Non-survivors had worse z-scores than survivors for all measurements, but this did not reach statistical significance. Log-transformed linear models generated new normative data for fetal left heart structures in left CDH, which may be used to allay antenatal concerns regarding structural left heart anomalies. There were no significant differences in z-scores between survivors and non-survivors, suggesting that in the absence of true structural disease, cardiac evaluation is not predictive in isolation and that causes of mortality are likely multifactorial in this population.

311 A new color Doppler-based echocardiographic technique for evaluation of intraventricular flow dynamics: first application to normal subjects, athletes, and patients

Abstract Aims A new echocardiographic, color Doppler-based technique, named HyperDoppler, has been recently introduced for non-invasive evaluation of intracardiac flow dynamics. The aim of this study was to verify the feasibility and reproducibility of this technique and its capability to differentiate geometrical and energy measures of vortex flow within the left ventricle (LV) in normal subjects, athletes and patients with heart failure. Methods and results Two Italian cardiology centres enrolled each one 100 unselected, consecutive patients presenting at the echocardiography laboratory for a clinical examination, regardless of the indication to echocardiography. In these patients, the feasibility, repeatability, reproducibility, and inter-centre reproducibility of the HyperDoppler technique were tested using the intraclass correlation coefficient (ICC) and Bland–Altman analysis. In addition, 50 normal subjects, 30 professional athletes, and 50 patients with stabilized chronic heart failure and LV ejection fraction &amp;lt;40% were enrolled. Images were acquired using a MyLab X8 echo-scanner and analysed to provide the following vortex flow measures: vortex area, normalized with the LV area; vortex intensity (i.e. the integral of the vorticity inside the vortex), normalized with the total vorticity; vortex depth (the distance of its centre from the LV base) and length along the base-apex direction, both normalized with the LV length; and the total kinetic energy dissipation (KED). Feasibility of HyperDoppler was very high (94.5%). According to the ICC values, at Centre 1 repeatability and reproducibility of vortex flow measures in unselected patients were good for vortex area (0.82, 0.85), length (0.83, 0.82) and depth (0.87, 0.84) and excellent for vortex intensity (0.92, 0.90) and KED (0.98, 0.98). Results of the Bland–Altman analysis showed no bias nor consistent under/overestimations of flow measures, with 95% of points always lying within the limits of agreement for each flow measure. Centre 2 provided similar repeatability and reproducibility evaluations for all the vortex measures, thus supporting a good-to-excellent inter-centre reproducibility. Athletes had greater vortex area, intensity, and KED compared to healthy subjects while they had smaller vortex length and depth and greater KED compared to patients with heart failure and reduced LV ejection fraction. In comparison with healthy subjects, heart failure patients showed greater vortex area, length, depth, and intensity but smaller KED. Combining vortex flow measures, the LV flow profile of healthy individuals, athletes, and heart failure patients could be differentiated. Conclusions HyperDoppler is a new ultrasound technique which is feasible, reliable, and practical for assessment of LV flow dynamics. It can quantitate several measures of the LV vortex and may distinguish normal subjects and patients. Future studies are needed to clarify how to implement this technique in cardiology clinical practice.

Evaluation of fetal cardiac functions in the setting of maternal diabetes: Application of the global spherical index, global strain and fractional area change by the speckle tracking technique

ObjectiveTo evaluate ventricular contractility and profile heart deformations in fetuses of hyperglycemic mothers using the Speckle tracking imaging (STI). The fractional area change (FAC), global longitudinal strain (GLS) and global sphericity index (GSI) of the 4-chamber view (4-CV) were computed. Study DesignDynamic 4-CV images of 60 fetuses exposed to maternal diabetes (MD) and 60 controls were retrospectively collected between 19 and 37 weeks of gestation. Speckle-tracking analysis was used to compute and compare GSI, GLS and FAC of the right ventricle (RV) and the left ventricle (LV) between the groups. By definition, GSI was the ratio of the epicardial basal–apical length in end-diastole (BAL) to the overall transverse length of RV and LV in end-diastole (TL). The FAC was calculated by dividing the difference between end-diastolic area and end-systolic area by the end-diastolic area. Similarly, the GLS of the RV and LV was obtained by dividing the difference between the endocardial length in end-systole and endocardial length in end-diastole to the endocardial length in end-diastole. Data for conventional echocardiographic parameters, standard biological measurements of fetus and maternal baseline characteristics were also recorded and compared between the groups. Linear regression analysis was performed to assess the association between age, BMI and the inter-ventricular septum thickness (IVST). ResultsGestational age at the time of examination did not differ significantly between the control and gestational diabetes group (p = 0.74). In fetuses exposed to MD, the thickness of the IVS was higher while the FAC of RV, GLS of RV and the GSI were all significantly lower. The FAC and global strain of LV generally decreased with progress in gestation but the difference between the two groups was not statistically significant. Conventional echocardiography in fetuses exposed to MD revealed a lower mitral E/A ratio and a larger myocardial performance index (MPI) of the RV and LV. Although the annular plane systolic excursion (MAPSE), tricuspid annular plane systolic excursion (TAPSE) and septal annular plane systolic excursion (SAPSE) were also lower in this group, the difference was not statistically significant compared to fetuses of the control group. No regression relationship between age, BMI and IVST were noticed in any group. ConclusionThis study found that diastolic dysfunction among fetuses of gestational diabetic mothers is accompanied by global cardiac deformation and functional decrease of the RV in systole in the second and third trimester. The GSI, global strain and FAC acquired by SRI can be used as convenient and reliable quantitative parameters in the assessment of cardiac function in fetuses exposed to gestational diabetes.

Patient size parameters to guide use of the Impella device in pediatric patients.

To define patient and ventricular size parameters to guide Impella device (Abiomed, Inc., Danvers, MA) placement for mechanical circulatory support (MCS) in small pediatric patients (10-30 kg). There are few options for MCS in children, and there are no data on minimum patient size requirements for placement of the Impella 2.5 device. This was a multicenter study of echocardiographic and magnetic resonance imaging (MRI) derived dimensions of the left ventricle (LV) length and ascending aorta used to define minimum size parameters that are necessary for the placement of the Impella catheter. Data were collected from 44 cardiac MRIs conducted in healthy pediatric patients and 39 echocardiograms performed in pediatric patients with cardiomyopathy prior to surgical ventricular assist device (VAD) placement. The Impella 2.5 catheter is 7.5 cm from the pigtail to the aortic annulus marker, thus requiring an LV apical length of 7.5 cm to allow the device to function in an unconstrained fashion. In the cohort of patients undergoing consideration for VAD placement, a minimum LV length of 7.5 cm corresponded to a height of 122 cm, weight of 23 kg, and body surface area (BSA) of 0.89 m2 . In the MRI cohort, this corresponded to a height of 121 cm, weight of 23.9 kg, and BSA of 0.89 m2 . MCS with Impella devices is feasible in pediatric patients. This study defines anthropomorphic and anatomic measurements to guide providers in patient selection for MCS using the Impella devices.

Left ventricular vortex formation in preterm infants assessed by blood speckle imaging.

A vortex is a rotational fluid structure formed by shearing of fluid layers. It forms during diastole in the left ventricle (LV) and helps redirect flow to the LV outflow tract for ejection, optimizing energy conservation. The aim of this study was to demonstrate the feasibility of detecting and analyzing LV vortices using a new ultrasound technique known as blood speckle imaging (BSI). Conventional and BSI parameters were acquired in preterm infants referred for echocardiography. BSI feasibility and reliability were explored using highest frequency settings and optimized Nyquist limits. Vortex area was determined by tracing the outer vortex ring at maximum area. Peak vortex formation time (PVFT) was determined at time of maximum vortex area relative to the R-wave, and vortex duration from frame-by-frame analysis of first appearance to vortex degradation. Left ventricle vortices were detected in 49 of the 50 preterm infants (weight 500-2020g) with excellent intra- and inter-observer reliability. Mean vortex area indexed to LV area was 0.19 (0.08). Peak vortex formation time was at 87 (7)% of the cardiac cycle, and vortex duration lasted 13 (4)% of the cardiac cycle. Vortex area correlated positively with LV length, end-diastolic dimension, end-diastolic volume, mitral annular (R +0.42, +0.50, +0.47, +0.50, all P<0.01), and transmitral Vti (R +0.37, P<0.01). PVFT correlated negatively with E, EA, and Ee' (R -0.42, -0.47, -0.47, all P<0.01). Left ventricle vortex formation can be analyzed with two-dimensional BSI and has the potential to complement existing parameters of cardiac health.

Novel Cardiac Coordinate Modeling System for Three-Dimensional Quantification of Inflow Cannula Malposition of HeartMate II LVADs.

Optimal function of left ventricular assist devices (LVADs) depends on proper alignment of the inflow cannula (IC). Quantitative guidelines for IC angulation are lacking because of variation in cardiac geometry and difficulty in analyzing three-dimensional (3D) cannula orientation relative to the left ventricle (LV). Based on contrast-enhanced computed tomography images from five normal and five clinically malpositioned IC cases in patients with HeartMate II LVADs, we developed a method for 3D quantification of IC malpositioning. Using Mimics image software (Materialise, Leuven, Belgium), the native heart, major arteries, and LVAD were segmented to create patient-specific 3D models, allowing LV cavity volume and long-axis length to be measured directly. The deviation of the IC was quantified in a cylindrical coordinate system at the IC insertion point relative to the mitral valve and septum, and IC occlusion was assessed by the distance between cannula inlet and the proximal endocardium. Compared with normal cases, patients with malpositioned pumps had shorter LV length (p = 0.03) and reduced pump pocket depth (p = 0.009). Malpositioned pumps may experience greater obstruction by the nearby myocardium. This quantitative 3D modeling tool may help identify different modes of pump malalignment and migration and may facilitate preoperative planning and minimally invasive approaches via virtual LVAD implantation.

Evaluation of the anatomic and hemodynamic abnormalities in tricuspid atresia before and after surgery using computational fluid dynamics.

Analysis of hemodynamics inside tricuspid atresia (TA) chamber is essential to the understanding of TA for optimal treatment. In this study, we introduced a combined computational fluid dynamics (CFD) to simulate blood flow in the left ventricle (LV) to study the diastolic flow changes in TA.Real-time 3-dimentional echocardiography loops (ECHO) were acquired in normal control group, in TA patients before surgery (pre-op group) and after surgery (post-op group). ECHO loops were reconstructed and simulated by CFD, the geometric, volumetric changes, and vortices in the LV were studies and compare among 3 groups.Compared with the control group, pre-op TA patients demonstrated significant LV remodeling, manifesting with smaller LV length, larger diameter, width and spherical index, as well as lager volumes; post-op TA group showed revisions in values of both geometric and volumetric measurements. CDF also demonstrated the abnormality of vortices in the pre-op TA patients and the alteration of existence and measurements of vortex in postoperation group.Echo-based CFD modeling can show the abnormality of TA in both LV geometric, volumetric measurements and intracardiac vortices; and CFD is capable to demonstrate the alterations of LV after Fontan and Glenn surgical procedure.

Should we Correct Mitral Annular Plane Systolic Excursion for Left Ventricle Length When Evaluating Left Ventricle Long-Axis Function with Cardiovascular Magnetic Resonance?

Should we Correct Mitral Annular Plane Systolic Excursion for Left Ventricle Length When Evaluating Left Ventricle Long-Axis Function with Cardiovascular Magnetic Resonance?

Evolution of Left Ventricular Size in Late Survivors of Surgery for Hypoplastic Left Heart Syndrome

Aortic atresia and mitral atresia are predictors of adverse events in early life in patients with hypoplastic left heart syndrome, but it is unclear whether late outcomes are also affected, and whether this impact is related to a small hypertrophied left ventricle (LV) that impairs right ventricle (RV) function. Thirty patients with hypoplastic left heart syndrome surviving with a Fontan procedure were identified. Follow-up echocardiograms were available at birth, before the Fontan procedure, and several years after. Mean follow-up time was 10.9 ± 3.1 years. Measurements included interventricular septum thickness and ventricular length. The LV/RV length ratio at birth was calculated, and its impact on later LV and septal growth was examined. The primary endpoint was a composite of death, transplantation, or Fontan takedown. A cutoff LV/RV length ratio of 0.55 was identified: length ratio was 0.55 or less in group A (18patients) and more than 0.55 in group B (12 patients) The LV/RV length ratio and interventricular septum thickness decreased over time in group A while remaining static in group B. The LV length at birth did not affect late adverse outcomes (hazard ratio 2.7, 95% confidence interval: 0.31 to 23.4, p= 0.37), whereas aortic atresia and mitral atresia were the most potent predictors of death or transplantation or takedown (hazard ratio 8.5, 95% confidence interval: 1.2 to 57.7, p= 0.029). Patients with aortic atresia and mitral atresia have worse outcomes even after Fontan independently of a small, thick, hypertrophied LV. The most severely hypoplastic LVs do not grow proportionally as much as the RVs.

63 Effect of Preload Reduction on Left Ventricular Torsion in Patients with Heart Failure and Preserved Ejection Fraction on Maintenance Haemodialysis

BackgroundThe effects of dialysis on diastolic flow, short and long axis function have been previously studied. However its effect on left ventricle (LV) rotation and torsion is not known. LV...

Echocardiographic Assessment of Left Ventricular Twisting and Untwisting Rate in Normal Subjects by Tissue Doppler and Velocity Vector Imaging: Comparison of Two Methods

Background: The torsional parameters of the left ventricle (LV) are sensitive indicators of the cardiac performance. The torsion/twist of the LV is the wringing motion of the heart around its long axis created by oppositely directed apical and basal rotations and is determined by contracting myofibers in the LV wall which are arranged in opposite directions between the subendocardial and subepicardial layers. This motion is essential for regulating the LV systolic and diastolic functions. Objectives: Recent advances in echocardiography techniques have allowed for quantification of LV mechanics. The aim of the present study was to compare various LV twisting and untwisting parameters in healthy human subjects determined by velocity vector imaging (VVI) and tissue Doppler imaging (TDI) at rest. Patients and Methods: All volunteers (47 healthy subjects in two groups: 24 subjects in VVI group and 23 subjects in TDI group) underwent complete echocardiographic study, and LV torsional parameters were assessed by VVI or TDI methods. In addition, LV torsion and LV twisting/untwisting rate profiles were calculated throughout cardiac cycle. Results: Twist degree was significantly lower in the VVI group than in the TDI group (P = 0.008, r = 0.56). LV torsion was lower in the VVI group but was not significant. (P = 0.13, r = 0.38). Twisting rate (P = 0.004, r = 0.66) and untwisting rate (P = 0.0001, r = 0.61) were lower in the VVI group, but when timing of untwisting rate was normalized by systolic duration, there was no significant difference between the two groups (P = 0.41, r = 0.59). Similarly, when peak untwisting rate was normalized by LV length, there was a significant decline in normalized peak untwisting rate in the VVI group (P = 0.004, r = 0.62), but not in peak twisting rate normalized by LV length (P = 0.12, r = 0.42). Peak untwisting rate normalized by LV torsion was not statistically different between the two groups (P = 0.05, r = 0.53). Conclusions: Results suggest that these methods cannot be interchanged, and VVI showed significantly lower LV peak twist, peak twisting rate and peak untwisting rate. However, when LV twist and LV twisting rates were normalized to LV length, values were comparable for both imaging techniques.

Long axis strain by MRI and echocardiography in a postmyocardial infarct population

To compare long axis strain (LAS) by magnetic resonance imaging (MRI) and echocardiography in a postinfarct patient population. Long axis left ventricle (LV) function is a sensitive index of incipient heart failure by echocardiography, but is less well established in MRI. LAS is an index of global LV function, which is easily assessed in cine loops provided by most cardiac MRI protocols. In all, 116 patients (57 ± 9 years) were studied the same day using echocardiography and MRI 7.4 ± 4.1 months after a first myocardial infarction. LV length was measured in end diastole and end systole in conventional cine images with a temporal resolution of 50 msec or less, and LAS (%) was calculated as the change in LV length, relative to end diastole. Infarct mass was assessed by contrast-enhanced MRI. LAS was progressively reduced in patients with larger infarcts, and demonstrated good correlations with infarct mass (r = 0.55, P < 0.01). There was a good agreement between LAS assessed by echocardiography and MRI (r = 0.77, P < 0.01), and between LAS by MRI and speckle tracking strain by echocardiography (r = 0.74, P < 0.01). LAS is an index that allows measurement of LV long axis function by conventional cine MRI.

Age, gender, blood pressure, and ventricular geometry influence normal 3D blood flow characteristics in the left heart

The aim of this study was to assess the effect of age, gender, physiological, and global cardiac function parameters on differences in normal 3D blood flow in the left ventricle (LV) and atrium (LA) using 4D flow magnetic resonance imaging (MRI). Four-dimensional flow MRI was acquired in healthy volunteers of two age and gender groups: <30 years (6 women, n = 12) and >50 years (6 women, n = 12). Systolic and early to mid-diastolic vortex flow (number of vortices, duration, area, peak velocity inside the vortex) in the LA and LV was assessed using intra-cardiac flow visualization based on 3D particle traces and velocity vector fields. A larger number of vortices in the LA were found in young compared with older individuals (number of diastolic vortices: 1.6 ± 0.8 vs. 0.7 ± 0.7, P = 0.01) with higher velocities (54 ± 12 cm/s vs. 41 ± 11 cm/s in systole, 47 ± 13 vs. 31 ± 8 cm/s in diastole, P < 0.05). Vortices in the LV base were smaller in women compared with men (369 ± 133 vs. 543 ± 176 mm(2), P = 0.009), while vortex size was increased in mid-ventricular locations (maximum area: 546 ± 321 vs. 293 ± 174 mm(2), P < 0.05). Correlation analysis revealed significant relationships (P = 0.005-0.048, correlation coefficients = 0.44-0.84) between LA and LV vortex characteristics (number, size, vortex velocities) and blood pressure as well as end-diastolic volume, LV length, and ejection fraction. Flow patterns in the left heart demonstrated differences related to age, gender, blood pressure, and ventricular geometry. The findings constitute a prerequisite for the understanding of the impact of cardiac disease on intra-cardiac haemodynamics.

Left Ventricular Remodeling in Human Heart Failure: Quantitative Echocardiographic Assessment of 1,794 Patients

The left ventricle (LV) undergoes significant architectural remodeling in heart failure (HF). However, the fundamental associations between cardiac function and LV size and performance have not been thoroughly characterized in this population. We sought to define the adaptive remodeling that occurs in chronic human HF through the detailed analyses of a large quantitative echocardiography database. Baseline echocardiograms were performed in 1,794 patients with HF across a broad range of ejection fraction (EF), from less than 10% to greater than 70%. Core lab measurements of LV volumes and length were made, from which EF, mass, sphericity indices, stroke volume (SV), and stroke work were derived. Spearman correlation coefficients and linear regression methods were used to determine the relationships between remodeling parameters. The median EF was 28.6% (IQR 21.9-37.0). Across a multitude of parameters of cardiac structure and function, indexed end-systolic volumes (ESVs) explained the greatest proportion of the variance in EF (R =-0.87, P < 0.0001). Systolic sphericity index and LV mass were also strongly correlated with EF (R =-0.62 and -0.63, P < 0.0001), reflective of the alterations in LV shape and size that occur as EF declines. SV was rigorously maintained across a broad spectrum of EF, until the EF fell below 20%, at which point SV decreased significantly (P < 0.0001). In chronic HF, the LV undergoes extensive structural adaptive remodeling in order to maintain SV across a broad range of EF. However, when the EF falls below 20%, further modulation of SV is no longer possible through alterations in ventricular architecture.

A novel cardiac magnetic resonance imaging technique to evaluate left ventricular diastolic function in patients with hypertrophic cardiomyopathy

Background The temporal and spatial resolution of cardiac magnetic resonance (CMR) imaging allows precise tracking of the left ventricle (LV) atrioventricular junction (AVJ) throughout the cardiac cycle. Similar to tissue Doppler imaging in echocardiography, AVJ motion assessed by CMR reflects diastolic LV function. A prior study by our group demonstrated significant differences in the displacement and velocity of the AVJ during diastole in patients with heart failure with preserved ejection fraction compared to normal hearts. In the current study we hypothesized that diastolic left ventricular function defined by AVJ motion is abnormal in patients with hypertrophic cardiomyopathy (HCM), a group known to have altered LV relaxation properties. Methods We retrospectively identified 24 patients with known or suspected HCM and normal ejection fractions who underwent CMR as part of their clinical assessment and 14 normal control subjects. The longitudinal motion of the lateral and septal AVJs was tracked at 25 times through the cardiac cycle using the 4-chamber cine CMR view . The baseline position of the AVJ was defined at end diastole and its longitudinal displacement was measured relative to a reference line drawn between the LV apex and the midpoint of the mitral annnulus. The displacement of the AVJ in relation to its starting position at end diastole was normalized by LV length. Based on the resulting plots of AVJ position versus time in the cardiac cycle (see figure below) five motion variables were calculated: maximum longitudinal displacement (MD) of the AVJ, maximum velocity during early diastole (MVED), velocity at half-maximal displacement during early diastole (VHMDED), slope of the best fit line of displacement in diastasis (VDS), and the ratio of VDS/MVED. Data obtained in HCM patients were compared to normal control subjects using the Student t-test. Results Means and standard deviations were calculated for each of the AVJ motion variables (MD, VHMDED, MVED, VDS, VDS/MVED) for the septal (S) and lateral walls (LW) of HCM patients and normal control subjects. Lateral and septal AVJ data were directly compared to the corresponding walls in patients and controls. We found highly statistically significant differences in MD and the four CMR correlates of diastolic LV function (VHMDED, MVED, VDS, VDS/MVED) in patients with HCM compared to normal controls, as noted in the table below. Conclusions Novel CMR correlates of diastolic left ventricular function are markedly abnormal in patients with HCM. Measured at the AVJ, patients with HCM had significantly less maximal displacements, slower velocities during early diastolic filling, and higher velocities during diastasis compared to normal control subjects. The evaluation of AVJ motion by CMR may provide a new method to assess diastolic function.

087 Left ventricle shape and trabeculations in idiopathic dilated cardiomyopathy assessed by cardiac magnetic resonance imaging

Idiopathic dilated cardiomyopathies (IDC) frequently develop left ventricle (LV) hypertrabeculation which bring to doubt about the diagnostic of LV non compaction (LVNC). The high spatial resolution of cardiac magnetic resonance imaging (CMR) allows distinguishing myocardial trabeculations explaining the exponential rise in the number of reports describing LVNC. To study the correlation between the LV shape and myocardial trabeculations regarding the BNP level in a population of IDC. Between November 2007 and November 2009, 48 IDC were prospectively assessed by CMR. Patients with echocardiographic LV ejection fraction (LVEF) > 45%, severe valvulopathy or usual criteria of LVNC were excluded. Patients with significant coronary artery disease (coronary stenosis > 50%) at the angiogram or subendocardium gadolinium delayed enhancement at the CMR were considered as ischemic cardiomyopathy and were excluded. LV end-diastolic volume (EDV) and end-systolic volume were measured by summing cine-CMR LV short axis slice. Sphericity index (SI) was defined as the ratio of LV end-diastolic diameter (EDD) on LV length measured respectively in midventricular short axis and midventricular 4 chambers cine-CMR views. LV trabeculation index (LVTI) was defined as the ratio of trabeculated on compacted layers thickness in a 16-segment model excluding apex. BNP was measured for each patient. Mean age was 52 ± 14 years with 29 (60%) men. Mean LVEF was 25 ± 10% with a mean indexed EDD of 37 ± 5 mm/m 2 and EDV of 135 ± 45 ml/m 2 . LVTI was not correlate with indexed EDV (r = 0.14; p = 0.34) and LVEF (r = 0.02, p = 0.9) but it was linearly correlated with SI (r = 0.26; p = 0.046) and had a tendency to have a negative correlation with BNP level (r = −0.26; p = 0.07). These results suggest that LV myocardial trabeculation thickness increases linearly with the LV shape sphericity and has a tendency to decrease with the rise of LV pressure regime assessed by BNP level.

Torsion of young hearts: a speckle tracking study of normal infants, children, and adolescents

Our aim was to study the rotational mechanics of the heart in a special population including neonates, young children, and adolescents. We showed the effect of age on torsion and the different rotational variables. This study is the first that focuses on neonatal heart mechanics. We recruited 70 normal children between few hours and 18 years old. We excluded abnormal rhythm and function. Short-axis parasternal views were taken at the base of the heart and the apex. Using the speckle tracking technique, we analysed the rotation curves at apex and base and calculated the net twist and torsion of the left ventricle (LV). We also calculated the twist and untwist rates to get the correlation with age and body surface area (BSA). Rotational patterns during diastole also were studied. Deformational time delay between the base and the apex was looked up. Apical rotation and net twist increased with age significantly (r = 0.41 and 0.38, respectively, P = 0.001) but when normalized by LV length there was fixed torsion among age groups. Rotation velocity declined with ageing during systole and diastole for both base and apex (r = -0.58 and -0.62 for twist rate, -0.69 and -0.6 for untwist rate, respectively, P < 0.001). Concordant results were reported for BSA. Deformational delay was decreasing with age (r = -0.74 for systolic and -0.53 for diastolic, P < 0.001). Infants hearts tend to deform more and faster than other groups. While apical twist and net twist increase with age, torsion is fixed among age groups. In young hearts, torsion is the result of differential twist.