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Sample records for left ventricle finite-element

  1. Finite element stress analysis of the human left ventricle whose irregular shape is developed from single plane cineangiocardiogram

    NASA Technical Reports Server (NTRS)

    Ghista, D. N.; Hamid, M. S.

    1977-01-01

    The three-dimensional left ventricular chamber geometrical model is developed from single plane cineangiocardiogram. This left ventricular model is loaded by an internal pressure monitored by cardiac catheterization. The resulting stresses in the left ventricular model chamber's wall are determined by computerized finite element procedure. For the discretization of this left ventricular model structure, a 20-node, isoparametric finite element is employed. The analysis and formulation of the computerised procedure is presented in the paper, along with the detailed algorithms and computer programs. The procedure is applied to determine the stresses in a left ventricle at an instant, during systole. Next, a portion (represented by a finite element) of this left ventricular chamber is simulated as being infarcted by making its active-state modulus value equal to its passive-state value; the neighbouring elements are shown to relieve the 'infarcted' element of stress by themselves taking on more stress.

  2. Incorporation of a Left Ventricle Finite Element Model Defining Infarction Into the XCAT Imaging Phantom

    PubMed Central

    Veress, Alexander I.; Segars, W. Paul; Tsui, Benjamin M. W.; Gullberg, Grant T.

    2011-01-01

    The 4D extended cardiac-torso (XCAT) phantom was developed to provide a realistic and flexible model of the human anatomy and cardiac and respiratory motions for use in medical imaging research. A prior limitation to the phantom was that it did not accurately simulate altered functions of the heart that result from cardiac pathologies such as coronary artery disease (CAD). We overcame this limitation in a previous study by combining the phantom with a finite-element (FE) mechanical model of the left ventricle (LV) capable of more realistically simulating regional defects caused by ischemia. In the present work, we extend this model giving it the ability to accurately simulate motion abnormalities caused by myocardial infarction (MI), a far more complex situation in terms of altered mechanics compared with the modeling of acute ischemia. The FE model geometry is based on high resolution CT images of a normal male subject. An anterior region was defined as infarcted and the material properties and fiber distribution were altered, according to the bio-physiological properties of two types of infarction, i.e., fibrous and remodeled infarction (30% thinner wall than fibrous case). Compared with the original, surface-based 4D beating heart model of the XCAT, where regional abnormalities are modeled by simply scaling down the motion in those regions, the FE model was found to provide a more accurate representation of the abnormal motion of the LV due to the effects of fibrous infarction as well as depicting the motion of remodeled infarction. In particular, the FE models allow for the accurate depiction of dyskinetic motion. The average circumferential strain results were found to be consistent with measured dyskinetic experimental results. Combined with the 4D XCAT phantom, the FE model can be used to produce realistic multimodality sets of imaging data from a variety of patients in which the normal or abnormal cardiac function is accurately represented. PMID:21041157

  3. Finite element analysis of left ventricle during cardiac cycles in viscoelasticity.

    PubMed

    Shen, Jing Jin; Xu, Feng Yu; Yang, Wen An

    2016-08-01

    To investigate the effect of myocardial viscoeslasticity on heart function, this paper presents a finite element model based on a hyper-viscoelastic model for the passive myocardium and Hill's three-element model for the active contraction. The hyper-viscoelastic model considers the myocardium microstructure, while the active model is phenomenologically based on the combination of Hill's equation for the steady tetanized contraction and the specific time-length-force property of the myocardial muscle. To validate the finite element model, the end-diastole strains and the end-systole strain predicted by the model are compared with the experimental values in the literature. It is found that the proposed model not only can estimate well the pumping function of the heart, but also predicts the transverse shear strains. The finite element model is also applied to analyze the influence of viscoelasticity on the residual stresses in the myocardium. PMID:27253618

  4. Quasi-static image-based immersed boundary-finite element model of left ventricle under diastolic loading

    PubMed Central

    Gao, Hao; Wang, Huiming; Berry, Colin; Luo, Xiaoyu; Griffith, Boyce E

    2014-01-01

    Finite stress and strain analyses of the heart provide insight into the biomechanics of myocardial function and dysfunction. Herein, we describe progress toward dynamic patient-specific models of the left ventricle using an immersed boundary (IB) method with a finite element (FE) structural mechanics model. We use a structure-based hyperelastic strain-energy function to describe the passive mechanics of the ventricular myocardium, a realistic anatomical geometry reconstructed from clinical magnetic resonance images of a healthy human heart, and a rule-based fiber architecture. Numerical predictions of this IB/FE model are compared with results obtained by a commercial FE solver. We demonstrate that the IB/FE model yields results that are in good agreement with those of the conventional FE model under diastolic loading conditions, and the predictions of the LV model using either numerical method are shown to be consistent with previous computational and experimental data. These results are among the first to analyze the stress and strain predictions of IB models of ventricular mechanics, and they serve both to verify the IB/FE simulation framework and to validate the IB/FE model. Moreover, this work represents an important step toward using such models for fully dynamic fluid–structure interaction simulations of the heart. © 2014 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons, Ltd. PMID:24799090

  5. Quasi-static image-based immersed boundary-finite element model of left ventricle under diastolic loading.

    PubMed

    Gao, Hao; Wang, Huiming; Berry, Colin; Luo, Xiaoyu; Griffith, Boyce E

    2014-11-01

    Finite stress and strain analyses of the heart provide insight into the biomechanics of myocardial function and dysfunction. Herein, we describe progress toward dynamic patient-specific models of the left ventricle using an immersed boundary (IB) method with a finite element (FE) structural mechanics model. We use a structure-based hyperelastic strain-energy function to describe the passive mechanics of the ventricular myocardium, a realistic anatomical geometry reconstructed from clinical magnetic resonance images of a healthy human heart, and a rule-based fiber architecture. Numerical predictions of this IB/FE model are compared with results obtained by a commercial FE solver. We demonstrate that the IB/FE model yields results that are in good agreement with those of the conventional FE model under diastolic loading conditions, and the predictions of the LV model using either numerical method are shown to be consistent with previous computational and experimental data. These results are among the first to analyze the stress and strain predictions of IB models of ventricular mechanics, and they serve both to verify the IB/FE simulation framework and to validate the IB/FE model. Moreover, this work represents an important step toward using such models for fully dynamic fluid-structure interaction simulations of the heart. © 2014 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons, Ltd. PMID:24799090

  6. Normal and Pathological NCAT Image and PhantomData Based onPhysiologically Realistic Left Ventricle Finite-Element Models

    SciTech Connect

    Veress, Alexander I.; Segars, W. Paul; Weiss, Jeffrey A.; Tsui,Benjamin M.W.; Gullberg, Grant T.

    2006-08-02

    The 4D NURBS-based Cardiac-Torso (NCAT) phantom, whichprovides a realistic model of the normal human anatomy and cardiac andrespiratory motions, is used in medical imaging research to evaluate andimprove imaging devices and techniques, especially dynamic cardiacapplications. One limitation of the phantom is that it lacks the abilityto accurately simulate altered functions of the heart that result fromcardiac pathologies such as coronary artery disease (CAD). The goal ofthis work was to enhance the 4D NCAT phantom by incorporating aphysiologically based, finite-element (FE) mechanical model of the leftventricle (LV) to simulate both normal and abnormal cardiac motions. Thegeometry of the FE mechanical model was based on gated high-resolutionx-ray multi-slice computed tomography (MSCT) data of a healthy malesubject. The myocardial wall was represented as transversely isotropichyperelastic material, with the fiber angle varying from -90 degrees atthe epicardial surface, through 0 degreesat the mid-wall, to 90 degreesat the endocardial surface. A time varying elastance model was used tosimulate fiber contraction, and physiological intraventricular systolicpressure-time curves were applied to simulate the cardiac motion over theentire cardiac cycle. To demonstrate the ability of the FE mechanicalmodel to accurately simulate the normal cardiac motion as well abnormalmotions indicative of CAD, a normal case and two pathologic cases weresimulated and analyzed. In the first pathologic model, a subendocardialanterior ischemic region was defined. A second model was created with atransmural ischemic region defined in the same location. The FE baseddeformations were incorporated into the 4D NCAT cardiac model through thecontrol points that define the cardiac structures in the phantom whichwere set to move according to the predictions of the mechanical model. Asimulation study was performed using the FE-NCAT combination toinvestigate how the differences in contractile function

  7. Dynamic finite-strain modelling of the human left ventricle in health and disease using an immersed boundary-finite element method

    PubMed Central

    Gao, Hao; Carrick, David; Berry, Colin; Griffith, Boyce E.; Luo, Xiaoyu

    2016-01-01

    Detailed models of the biomechanics of the heart are important both for developing improved interventions for patients with heart disease and also for patient risk stratification and treatment planning. For instance, stress distributions in the heart affect cardiac remodelling, but such distributions are not presently accessible in patients. Biomechanical models of the heart offer detailed three-dimensional deformation, stress and strain fields that can supplement conventional clinical data. In this work, we introduce dynamic computational models of the human left ventricle (LV) that are derived from clinical imaging data obtained from a healthy subject and from a patient with a myocardial infarction (MI). Both models incorporate a detailed invariant-based orthotropic description of the passive elasticity of the ventricular myocardium along with a detailed biophysical model of active tension generation in the ventricular muscle. These constitutive models are employed within a dynamic simulation framework that accounts for the inertia of the ventricular muscle and the blood that is based on an immersed boundary (IB) method with a finite element description of the structural mechanics. The geometry of the models is based on data obtained non-invasively by cardiac magnetic resonance (CMR). CMR imaging data are also used to estimate the parameters of the passive and active constitutive models, which are determined so that the simulated end-diastolic and end-systolic volumes agree with the corresponding volumes determined from the CMR imaging studies. Using these models, we simulate LV dynamics from enddiastole to end-systole. The results of our simulations are shown to be in good agreement with subject-specific CMR-derived strain measurements and also with earlier clinical studies on human LV strain distributions. PMID:27041786

  8. The direct incorporation of perfusion defect information to define ischemia and infarction in a finite element model of the left ventricle.

    PubMed

    Veress, Alexander I; Fung, George S K; Lee, Taek-Soo; Tsui, Benjamin M W; Kicska, Gregory A; Paul Segars, W; Gullberg, Grant T

    2015-05-01

    This paper describes the process in which complex lesion geometries (specified by computer generated perfusion defects) are incorporated in the description of nonlinear finite element (FE) mechanical models used for specifying the motion of the left ventricle (LV) in the 4D extended cardiac torso (XCAT) phantom to simulate gated cardiac image data. An image interrogation process was developed to define the elements in the LV mesh as ischemic or infarcted based upon the values of sampled intensity levels of the perfusion maps. The intensity values were determined for each of the interior integration points of every element of the FE mesh. The average element intensity levels were then determined. The elements with average intensity values below a user-controlled threshold were defined as ischemic or infarcted depending upon the model being defined. For the infarction model cases, the thresholding and interrogation process were repeated in order to define a border zone (BZ) surrounding the infarction. This methodology was evaluated using perfusion maps created by the perfusion cardiac-torso (PCAT) phantom an extension of the 4D XCAT phantom. The PCAT was used to create 3D perfusion maps representing 90% occlusions at four locations (left anterior descending (LAD) segments 6 and 9, left circumflex (LCX) segment 11, right coronary artery (RCA) segment 1) in the coronary tree. The volumes and shapes of the defects defined in the FE mechanical models were compared with perfusion maps produced by the PCAT. The models were incorporated into the XCAT phantom. The ischemia models had reduced stroke volume (SV) by 18-59 ml. and ejection fraction (EF) values by 14-50% points compared to the normal models. The infarction models, had less reductions in SV and EF, 17-54 ml. and 14-45% points, respectively. The volumes of the ischemic/infarcted regions of the models were nearly identical to those volumes obtained from the perfusion images and were highly correlated (R

  9. Double inlet left ventricle

    MedlinePlus

    ... born with this condition have only one working pumping chamber (ventricle) in their heart. ... condition generally have a large left ventricle (the pumping chamber of the heart that supplies the body ...

  10. Left ventricular finite element model bounded by a systemic circulation model.

    PubMed

    Veress, A I; Raymond, G M; Gullberg, G T; Bassingthwaighte, J B

    2013-05-01

    A series of models were developed in which a circulatory system model was coupled to an existing series of finite element (FE) models of the left ventricle (LV). The circulatory models were used to provide realistic boundary conditions for the LV models. This was developed for the JSim analysis package and was composed of a systemic arterial, capillary, and venous system in a closed loop with a varying elastance LV and left atria to provide the driving pressures and flows matching those of the FE model. Three coupled models were developed, a normal LV under normotensive aortic loading (116/80 mm Hg), a mild hypertension (137/89 mm Hg) model, and a moderate hypertension model (165/100 mm Hg). The initial step in the modeling analysis was that the circulation was optimized to the end-diastolic pressure and volume values of the LV model. The cardiac FE models were then optimized to the systolic pressure/volume characteristics of the steady-state JSim circulatory model solution. Comparison of the stress predictions for the three models indicated that the mild hypertensive case produced a 21% increase in the average fiber stress levels, and the moderate hypertension case had a 36% increase in average stress. The circulatory work increased by 18% and 43% over that of the control for the mild and moderate hypertensive cases, respectively. PMID:24231963

  11. Pseudoaneurysm of the left ventricle.

    PubMed Central

    Mackenzie, J W; Lemole, G M

    1994-01-01

    Pseudoaneurysm of the left ventricle most often occurs after transmural myocardial infarction but may also follow cardiac operations, trauma, inflammation, or infection. In contrast to patients with true ventricular aneurysm, those with false aneurysm most commonly die of hemorrhage. Review of the reported surgical experience and of our 14 cases confirms that standard chest radiographs with an abnormal cardiac silhouette and rapidly expanding size may alert the physician to this sometimes overlooked diagnosis. Noninvasive tests such as color-flow Doppler echocardiography, 2-dimensional echocardiography, cineangiographic computed tomography, and transesophageal echocardiography allow relatively easy recognition of these apparently rare lesions with increasing frequency. Cardiac catheterization, however, is usually still necessary for a clear picture of the location and anatomy of the aneurysm and the state of the coronary arteries. Finally, a new classification is proposed, consisting of true aneurysm, false aneurysm, pseudo-false aneurysm, and mixed aneurysm. Images PMID:7888805

  12. Regional left ventricular myocardial contractility and stress in a finite element model of posterobasal myocardial infarction.

    PubMed

    Wenk, Jonathan F; Sun, Kay; Zhang, Zhihong; Soleimani, Mehrdad; Ge, Liang; Saloner, David; Wallace, Arthur W; Ratcliffe, Mark B; Guccione, Julius M

    2011-04-01

    Recently, a noninvasive method for determining regional myocardial contractility, using an animal-specific finite element (FE) model-based optimization, was developed to study a sheep with anteroapical infarction (Sun et al., 2009, "A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm," ASME J. Biomech. Eng., 131(11), p. 111001). Using the methodology developed in the previous study (Sun et al., 2009, "A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular Aneurysm," ASME J. Biomech. Eng., 131(11), p. 111001), which incorporates tagged magnetic resonance images, three-dimensional myocardial strains, left ventricular (LV) volumes, and LV cardiac catheterization pressures, the regional myocardial contractility and stress distribution of a sheep with posterobasal infarction were investigated. Active material parameters in the noninfarcted border zone (BZ) myocardium adjacent to the infarct (T(max_B)), in the myocardium remote from the infarct (T(max_R)), and in the infarct (T(max_I)) were estimated by minimizing the errors between FE model-predicted and experimentally measured systolic strains and LV volumes using the previously developed optimization scheme. The optimized T(max_B) was found to be significantly depressed relative to T(max_R), while T(max_I) was found to be zero. The myofiber stress in the BZ was found to be elevated, relative to the remote region. This could cause further damage to the contracting myocytes, leading to heart failure. PMID:21428685

  13. Chronic obstructive pulmonary disease and left ventricle.

    PubMed

    Portillo, Karina; Abad-Capa, Jorge; Ruiz-Manzano, Juan

    2015-05-01

    Several studies have shown that the interaction between chronic obstructive pulmonary disease (COPD) and cardiovascular comorbidity is complex and bidirectional, since each of these diseases complicates the prognosis of the other. Recent advances in imaging technology have led to better characterization of cardiac chambers and allowed the relationship between certain cardiac function parameters and COPD clinical and functional variables to be explored. Although cardiac abnormalities in COPD have been mainly associated with the right ventricle, several studies have reported that the left ventricle may also be affected in this disease. A better understanding of the mechanisms involved and their clinical implications will establish diagnostic and therapeutic strategies for patients with both these conditions. PMID:24816034

  14. Finite element analysis of stresses developed in the blood sac of a left ventricular assist device.

    PubMed

    Haut Donahue, T L; Dehlin, W; Gillespie, J; Weiss, W J; Rosenberg, G

    2009-05-01

    The goal of this research is to develop a 3D finite element (FE) model of a left ventricular assist device (LVAD) to predict stresses in the blood sac. The hyperelastic stress-strain curves for the segmented poly(ether polyurethane urea) (SPEUU) blood sac were determined in both tension and compression using a servo-hydraulic testing system at various strain rates. Over the range of strain rates studied, the sac was not strain rate sensitive, however the material response was different for tension versus compression. The experimental tension and compression properties were used in a FE model that consisted of the pusher plate, blood sac and pump case. A quasi-static analysis was used to allow for nonlinearities due to contact and material deformation. The 3D FE model showed that blood sac stresses are not adversely affected by the location of the inlet and outlet ports of the device and that over the systolic ejection phase of the simulation the prediction of blood sac stresses from the full 3D model and an axisymmetric model are the same. Minimizing stresses in the blood sac will increase the longevity of the blood sac in vivo. PMID:19131267

  15. MRI-based finite-element analysis of left ventricular aneurysm.

    PubMed

    Walker, Joseph C; Ratcliffe, Mark B; Zhang, Peng; Wallace, Arthur W; Fata, Bahar; Hsu, Edward W; Saloner, David; Guccione, Julius M

    2005-08-01

    Tagged MRI and finite-element (FE) analysis are valuable tools in analyzing cardiac mechanics. To determine systolic material parameters in three-dimensional stress-strain relationships, we used tagged MRI to validate FE models of left ventricular (LV) aneurysm. Five sheep underwent anteroapical myocardial infarction (25% of LV mass) and 22 wk later underwent tagged MRI. Asymmetric FE models of the LV were formed to in vivo geometry from MRI and included aneurysm material properties measured with biaxial stretching, LV pressure measurements, and myofiber helix angles measured with diffusion tensor MRI. Systolic material parameters were determined that enabled FE models to reproduce midwall, systolic myocardial strains from tagged MRI (630 +/- 187 strain comparisons/animal). When contractile stress equal to 40% of the myofiber stress was added transverse to the muscle fiber, myocardial strain agreement improved by 27% between FE model predictions and experimental measurements (RMS error decreased from 0.074 +/- 0.016 to 0.054 +/- 0.011, P < 0.05). In infarct border zone (BZ), end-systolic midwall stress was elevated in both fiber (24.2 +/- 2.7 to 29.9 +/- 2.4 kPa, P < 0.01) and cross-fiber (5.5 +/- 0.7 to 11.7 +/- 1.3 kPa, P = 0.02) directions relative to noninfarct regions. Contrary to previous hypotheses but consistent with biaxial stretching experiments, active cross-fiber stress development is an integral part of LV systole; FE analysis with only uniaxial contracting stress is insufficient. Stress calculations from these validated models show 24% increase in fiber stress and 115% increase in cross-fiber stress at the BZ relative to remote regions, which may contribute to LV remodeling. PMID:15778283

  16. [Surgical treatment of double outlet left ventricle].

    PubMed

    Planché, C; Pernot, C; Batisse, A; Kachaner, J; Langlois, J; Bruniaux, J; Binet, J P

    1979-05-01

    Three young patients with double outlet left ventricle were operated on at the Centre chirurgica Marie-Lannelongue. There was one secondary death. The follow up period of the two survivors is 24 months and 8 months respectively. The diagnosis of this rare congenital abnormality is difficult because of the multiplicity of the anatomical changes and the diversity of the final clinical entity. This is reflected in the attempts at classification. These difficulties are increased by the high incidence of incomplete forms of the condition which gives rise, especially in vivo, to problems of terminology. Echocardiography provides valuable information in the diagnosis of these forms by showing the abnormal relationship between the interventricular septum and the origin of the great vessels. A complete work up is essential before any decision can be made on management. Particular importance is placed on the topographical and morphological features of the atria and ventricles, the connections of the aorta and pulmonary arteries, and the state of the pulmonary tract. Modern surgical techniques have made correction possible in most forms of the disease, but involves complex procedures which leaves doubts on their long term outcome. PMID:115403

  17. The hypertrabeculated (noncompacted) left ventricle is different from the ventricle of embryos and ectothermic vertebrates.

    PubMed

    Jensen, Bjarke; Agger, Peter; de Boer, Bouke A; Oostra, Roelof-Jan; Pedersen, Michael; van der Wal, Allard C; Nils Planken, R; Moorman, Antoon F M

    2016-07-01

    Ventricular hypertrabeculation (noncompaction) is a poorly characterized condition associated with heart failure. The condition is widely assumed to be the retention of the trabeculated ventricular design of the embryo and ectothermic (cold-blooded) vertebrates. This assumption appears simplistic and counterfactual. Here, we measured a set of anatomical parameters in hypertrabeculation in man and in the ventricles of embryos and animals. We compared humans with left ventricular hypertrabeculation (N=21) with humans with structurally normal left ventricles (N=54). We measured ejection fraction and ventricular trabeculation using cardiovascular MRI. Ventricular trabeculation was further measured in series of embryonic human and 9 animal species, and in hearts of 15 adult animal species using MRI, CT, or histology. In human, hypertrabeculated left ventricles were significantly different from structurally normal left ventricles by all structural measures and ejection fraction. They were far less trabeculated than human embryonic hearts (15-40% trabeculated volume versus 55-80%). Early in development all vertebrate embryos acquired a ventricle with approximately 80% trabeculations, but only ectotherms retained the 80% trabeculation throughout development. Endothermic (warm-blooded) animals including human slowly matured in fetal and postnatal stages towards ventricles with little trabeculations, generally less than 30%. Further, the trabeculations of all embryos and adult ectotherms were very thin, less than 50 μm wide, whereas the trabeculations in adult endotherms and in the setting of hypertrabeculation were wider by orders of magnitude. It is concluded in contrast to a prevailing assumption, the hypertrabeculated left ventricle is not like the ventricle of the embryo or of adult ectotherms. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes

  18. Recovery of the 3-D shape of the left ventricle from echocardiographic images.

    PubMed

    Coppini, G; Poli, R; Valli, G

    1995-01-01

    A computational method is reported which allows the fully automated recovery of the three-dimensional shape of the cardiac left ventricle from a reduced set of apical echo views. Two typically ill-posed problems have been faced: 1) the detection of the left ventricle contours in each view, and 2) the integration of the detected contour points (which form a sparse and partially inconsistent data set) into a single surface representation. The authors' solution to these problems is based on a careful integration of standard computer vision algorithms with neural networks. Boundary detection comprises three steps: edge detection, edge grouping, and edge classification. The first and second steps (which are typical early-vision tasks not involving specific domain-knowledge) have been performed through fast, well-established algorithms of computer vision. The higher level task of left ventricle-edge discrimination, which involves the exploitation of specific knowledge about the left ventricle silhouette, has been performed by feedforward neural networks. Following the most recent results in the field of computer vision, the first step in solving the problem of recovering the ventricle surface has been the adoption of a physically inspired model of it. Basically, the authors have modeled the left ventricle surface as a closed, thin, elastic surface and the data as a set of radial springs acting on it. The recovery process is equivalent to the settling of the surface-plus-springs system into a stable configuration of minimum potential energy. The finite element discretization of this model leads directly to an analog neural-network implementation. The efficiency of such an implementation has been remarkably enhanced through a learning algorithm which embeds specific knowledge about the shape of the left ventricle in the network. Experiments using clinical echographic sequences are described. Four apical views (each with a different rotation of the probe) have been acquired

  19. Transcatheter closure of ruptured sinus of valsalva to left ventricle

    PubMed Central

    Manuel, Devi A; Lahiri, Anandaroop; George, Oommen K

    2016-01-01

    We report a rare case of ruptured right sinus of valsalva into the left ventricle (LV). Transthoracic echocardiography showed a marked turbulent flow from the right aortic sinus to the LV. We describe a novel technique of closure of this defect with duct occluder, involving the formation of an arterio-arterial loop, without resorting to the usual arteriovenous loop. PMID:27011698

  20. Transcatheter closure of ruptured sinus of valsalva to left ventricle.

    PubMed

    Manuel, Devi A; Lahiri, Anandaroop; George, Oommen K

    2016-01-01

    We report a rare case of ruptured right sinus of valsalva into the left ventricle (LV). Transthoracic echocardiography showed a marked turbulent flow from the right aortic sinus to the LV. We describe a novel technique of closure of this defect with duct occluder, involving the formation of an arterio-arterial loop, without resorting to the usual arteriovenous loop. PMID:27011698

  1. Rotational angiography of left ventricle to guide ventricular tachycardia ablation.

    PubMed

    Wolf, Jiri; Starek, Zdenek; Jez, Jiri; Lehar, Frantisek; Lukasova, Marketa; Kulik, Tomas; Novak, Miroslav

    2015-06-01

    Three-dimensional rotational angiography (3 DRA) is a novel imaging method introduced to guide complex catheter ablations of the left atrium. Our aim was to investigate the feasibility of the method in visualization of left ventricular anatomy and to develop a corresponding protocol for guidance of ventricular tachycardia ablation. We performed 3D rotational angiography in 13 patients using a direct left atrial protocol for data acquisition and the 3D reconstruction of the left ventricle was achieved in all patients. Clinical data comparison has proved lower use of radiation and contrast medium during 3 DRA-guided ablations as compared to CT-guided procedures. PMID:25761532

  2. An Inverse Finite Element Method for Determining the Tissue Compressibility of Human Left Ventricular Wall during the Cardiac Cycle

    PubMed Central

    Hassaballah, Abdallah I.; Hassan, Mohsen A.; Mardi, Azizi N.; Hamdi, Mohd

    2013-01-01

    The determination of the myocardium’s tissue properties is important in constructing functional finite element (FE) models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV) internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility), as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle. PMID:24367544

  3. An inverse finite element method for determining the tissue compressibility of human left ventricular wall during the cardiac cycle.

    PubMed

    Hassaballah, Abdallah I; Hassan, Mohsen A; Mardi, Azizi N; Hamdi, Mohd

    2013-01-01

    The determination of the myocardium's tissue properties is important in constructing functional finite element (FE) models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV) internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility), as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle. PMID:24367544

  4. Patient-specific simulation of a trileaflet aortic heart valve in a realistic left ventricle and aorta

    NASA Astrophysics Data System (ADS)

    Gilmanov, Anvar; Le, Trung; Stolarski, Henryk; Sotiropoulos, Fotis

    2013-11-01

    We develop a patient-specific model of the left ventricle consisting of: (1) magnetic-resonance images (MRI) data for wall geometry and kinematics reconstruction of the left ventricle during one cardiac cycle and (2) an elastic trileaflet aortic heart valve implanted in (3) a realistic aorta interacting with blood flow driven by the pulsating left ventricle. Blood flow is simulated via a new fluid-structure interaction (FSI) method, which couples the sharp-interface CURVIB [L. Ge, F. Sotiropoulos, JCP, (2007)] for handling complex moving boundaries with a new, rotation-free finite-element (FE) formulation for simulating large tissue deformations [H. Stolarski, A. Gilmanov, F. Sotiropoulos, IJNME, (2013)] The new FE shell formulation has been extensively tested and validated for a range of relevant problems showing good agreements. Validation of the coupled FSI-FE-CURVIB model is carried out for a thin plate undergoing flow-induced vibrations in the wake of a square cylinder and the computed results are in good agreement with published data. The new approach has been applied to simulate dynamic interaction of a trileaflet aortic heart valve with pulsating blood flow at physiological conditions and realistic artery and left ventricle geometry.

  5. Is the human left ventricle partially a fractal pump?

    NASA Astrophysics Data System (ADS)

    Moore, Brandon; Dasi, Lakshmi

    2011-11-01

    Ventricular systolic and diastolic dysfunctions represent a large portion of healthcare problems in the United States. Many of these problems are caused and/or characterized by their altered fluid-structure mechanics. The structure of the left ventricle in particular is complex with time dependent multi-scale geometric complexity. At relatively small scales, one facet that is still not well understood is the role of trabeculae in the pumping function of the left ventricle. We utilize fractal geometry tools to help characterize the complexity of the inner surface of the left ventricle at different times during the cardiac cycle. A high-resolution three dimensional model of the time dependent ventricular geometry was constructed from computed tomography (CT) images in a human. The scale dependent fractal dimension of the ventricle was determined using the box-counting algorithm over the cardiac cycle. It is shown that the trabeculae may indeed play an integral role in the biomechanics of pumping by regulating the mechanical leverage available to the cardiac muscle fibers.

  6. Chest tube injury to left ventricle: complication or negligence?

    PubMed

    Haron, Hairufaizi; Rashid, Norfaezan Abdul; Dimon, Mohd Zamrin; Azmi, Muhd Helmi; Sumin, Joanna Ooi; Zabir, Azmil Farid; Abdul Rahman, Mohd Ramzisham

    2010-07-01

    An injury to the left ventricle after a chest tube insertion is a rare but lethal phenomenon that is likely to occur if precautions are not seriously addressed. We present a 15-year-old girl who was diagnosed a left empyema thoracis. An attempt to place a chest drain in this young girl was almost fatal. A left ventricular repair together with thoracotomy and decortication were successful. This case emphasizes the rarity of this lethal complication and the importance of the correct technique for chest tube insertion. PMID:20609810

  7. [Pseudoaneurysm of the left ventricle: a report of 2 cases].

    PubMed

    Pomini, G; Lupia, M; Milano, A; Gribaldo, R

    1993-03-01

    Two cases of left ventricular pseudoaneurysm following myocardial infarction are presented. In the first patient a two-dimensional echocardiography study revealed a small posterior echo-free space that appeared to communicate with the left ventricle through a small defect in the left ventricular posterior wall. Conventional Doppler echocardiography and colour flow imaging demonstrated flow between the left ventricle and the paraventricular chamber. In the other patient, the same study detected an enormous false aneurysm. We found a large extramyocardial echo-free space within the pericardial cavity. The site of this space was posterolateral and communicating with the left ventricular cavity. Cardiac catheterization and surgery confirmed the diagnosis. A postoperative echocardiographic study demonstrated a persistent but smaller saccular echo-free space and a residual shunt through one site of repair in the first patient; in the other, after surgical treatment there was no residual flow, but a left ventricular dysfunction was detected. Two dimensional and color Doppler echocardiography is the best technique among the noninvasive methods, for detecting and following up left ventricular pseudoaneurysms. PMID:8325466

  8. Application of NASTRAN for stress analysis of left ventricle of the heart

    NASA Technical Reports Server (NTRS)

    Pao, Y. C.; Ritman, E. L.; Wang, H. C.

    1975-01-01

    Knowing the stress and strain distributions in the left ventricular wall of the heart is a prerequisite for the determination of the muscle elasticity and contractility in the process of assessing the functional status of the heart. NASTRAN was applied for the calculation of these stresses and strains and to help in verifying the results obtained by the computer program FEAMPS which was specifically designed for the plane-strain finite-element analysis of the left ventricular cross sections. Adopted for the analysis are the true shape and dimensions of the cross sections reconstructed from multiplanar X-ray views of a left ventricle which was surgically isolated from a dog's heart but metabolically supported to sustain its beating. A preprocessor was prepared to accommodate both FEAMPS and NASTRAN, and it has also facilitated the application of both the triangular element and isoparameteric quadrilateral element versions of NASTRAN. The stresses in several crucial regions of the left ventricular wall calculated by these two independently developed computer programs are found to be in good agreement. Such confirmation of the results is essential in the development of a method which assesses the heart performance.

  9. Left Ventricle Segmentation Using Model Fitting and Active Surfaces

    PubMed Central

    Tay, Peter C.; Li, Bing; Garson, Chris D.; Acton, Scott T.; Hossack, John A.

    2010-01-01

    A method to perform 4D (3D over time) segmentation of the left ventricle of a mouse heart using a set of B mode cine slices acquired in vivo from a series of short axis scans is described. We incorporate previously suggested methods such as temporal propagation, the gradient vector flow active surface, superquadric models, etc. into our proposed 4D segmentation of the left ventricle. The contributions of this paper are incorporation of a novel despeckling method and the use of locally fitted superellipsoid models to provide a better initialization for the active surface segmentation algorithm. Average distances of the improved surface segmentation to a manually segmented surface throughout the entire cardiac cycle and cross-sectional contours are provided to demonstrate the improvements produced by the proposed 4D segmentation. PMID:20300558

  10. Blood flow and wall motion in an idealized left ventricle

    NASA Astrophysics Data System (ADS)

    Tavoularis, Stavros; Doyle, Matthew; Bourgault, Yves

    2006-11-01

    During diastole of the heart, the left ventricle (LV) expands as a result of both incoming blood flow and wall material relaxation. In this work, we simulate both of these effects, along with the fluid-structure interaction between the blood and the heart wall. As a first step leading to more realistic studies, we approximate the LV by a prolate ellipsoid and the valves by cylindrical tubes. The mitral valve is open, allowing blood to enter the LV, whereas the aortic valve is closed. To account for the effects of muscle fibers in the heart wall, we model the wall as a multi-layered orthotropic linear elastic material with different material properties in the fiber, sheet, and sheet-normal directions within each layer. Results will be presented for this idealized configuration, while simulations of blood flow in realistic canine left and right ventricles are currently underway.

  11. Postoperative false aneurysm of left ventricle and obstruction of left circumflex coronary artery complicating enlargement of restrictive ventricular septal defect in double-outlet right ventricle.

    PubMed

    Edwards, W D; Wilcox, W D; Danielson, G K; Feldt, R H

    1980-07-01

    A case is reported of double-outlet right ventricle (DORV) with restrictive subaortic ventricular septal defect (VSD) in which enlargement of the defect at the time of surgical repair was associated with the late postoperative development of a false aneurysm of the left ventricle. The enlarging fale aneurysm caused extrinsic compression of the dominant left circumflex coronary artery, with subsequent ischemia and infarction of the posterolateral left ventricle. The anatomy and surgical implications of restrictive VSD are discussed. PMID:7382528

  12. Vortex formation and instability in the left ventricle

    NASA Astrophysics Data System (ADS)

    Le, Trung Bao; Sotiropoulos, Fotis; Coffey, Dane; Keefe, Daniel

    2012-09-01

    We study the formation of the mitral vortex ring during early diastolic filling in a patient-specific left ventricle (LV) using direct numerical simulation. The geometry of the left ventricle is reconstructed from Magnetic Resonance Imaging (MRI) data of a healthy human subject. The left ventricular kinematics is modeled via a cell-based activation methodology, which is inspired by cardiac electro-physiology and yields physiologic LV wall motion. In the fluid dynamics videos, we describe in detail the three-dimensional structure of the mitral vortex ring, which is formed during early diastolic filling. The ring starts to deform as it propagates toward the apex of the heart and becomes inclined. The trailing secondary vortex tubes are formed as the result of interaction between the vortex ring and the LV wall. These vortex tubes wrap around the circumference and begin to interact with and destabilize the mitral vortex ring. At the end of diastole, the vortex ring impinges on the LV wall and the large-scale intraventricular flow rotates in clockwise direction. We show for the first time that the mitral vortex ring evolution is dominated by a number of vortex-vortex and vortex-wall interactions, including lateral straining and deformation of vortex ring, the interaction of two vortex tubes with unequal strengths, helicity polarization of vortex tubes and twisting instabilities of the vortex cores.

  13. Endovascular Treatment of Two Pseudoaneurysms Originating From the Left Ventricle

    SciTech Connect

    Cwikiel, Wojciech Keussen, Inger; Gustafsson, Ronny; Mokhtari, Arash

    2013-12-15

    A 67-year-old woman resented with an acute type A aortic dissection, which was treated surgically with aortic valve replacement as a composite graft with reimplantation of the coronary arteries. At the end of surgery, a left-ventricular venting catheter was placed through the apex and closed with a buffered suture. Consecutive computed tomography (CT) examinations verified a growing apex pseudoaneurysm. Communication between the ventricle and the pseudoaneurysm was successfully closed with an Amplatz septal plug by the transfemoral route. Follow-up CT showed an additional pseudoaneurysm, which also was successfully closed using the same method.

  14. Stress and strain adaptation in load-dependent remodeling of the embryonic left ventricle

    PubMed Central

    Faas, Daniela; Sedmera, David

    2013-01-01

    Altered pressure in the developing left ventricle (LV) results in altered morphology and tissue material properties. Mechanical stress and strain may play a role in the regulating process. This study showed that confocal microscopy, three-dimensional reconstruction, and finite element analysis can provide a detailed model of stress and strain in the trabeculated embryonic heart. The method was used to test the hypothesis that end-diastolic strains are normalized after altered loading of the LV during the stages of trabecular compaction and chamber formation. Stage-29 chick LVs subjected to pressure overload and underload at stage 21 were reconstructed with full trabecular morphology from confocal images and analyzed with finite element techniques. Measured material properties and intraventricular pressures were specified in the models. The results show volume-weighted end-diastolic von Mises stress and strain averaging 50–82% higher in the trabecular tissue than in the compact wall. The volume-weighted-average stresses for the entire LV were 115, 64, and 147 Pa in control, underloaded, and overloaded models, while strains were 11, 7, and 4%; thus, neither was normalized in a volume-weighted sense. Localized epicardial strains at mid-longitudinal level were similar among the three groups and to strains measured from high-resolution ultrasound images. Sensitivity analysis showed changes in material properties are more significant than changes in geometry in the overloaded strain adaptation, although resulting stress was similar in both types of adaptation. These results emphasize the importance of appropriate metrics and the role of trabecular tissue in evaluating the evolution of stress and strain in relation to pressure-induced adaptation. PMID:23254562

  15. Measurement of Strain in the Left Ventricle during Diastole withcine-MRI and Deformable Image Registration

    SciTech Connect

    Veress, Alexander I.; Gullberg, Grant T.; Weiss, Jeffrey A.

    2005-07-20

    The assessment of regional heart wall motion (local strain) can localize ischemic myocardial disease, evaluate myocardial viability and identify impaired cardiac function due to hypertrophic or dilated cardiomyopathies. The objectives of this research were to develop and validate a technique known as Hyperelastic Warping for the measurement of local strains in the left ventricle from clinical cine-MRI image datasets. The technique uses differences in image intensities between template (reference) and target (loaded) image datasets to generate a body force that deforms a finite element (FE) representation of the template so that it registers with the target image. To validate the technique, MRI image datasets representing two deformation states of a left ventricle were created such that the deformation map between the states represented in the images was known. A beginning diastoliccine-MRI image dataset from a normal human subject was defined as the template. A second image dataset (target) was created by mapping the template image using the deformation results obtained from a forward FE model of diastolic filling. Fiber stretch and strain predictions from Hyperelastic Warping showed good agreement with those of the forward solution. The technique had low sensitivity to changes in material parameters, with the exception of changes in bulk modulus of the material. The use of an isotropic hyperelastic constitutive model in the Warping analyses degraded the predictions of fiber stretch. Results were unaffected by simulated noise down to an SNR of 4.0. This study demonstrates that Warping in conjunction with cine-MRI imaging can be used to determine local ventricular strains during diastole.

  16. A new approach to assessment of the left ventricle

    PubMed Central

    Poppe, Katrina K.; Doughty, Rob N.; Whalley, Gillian A.; Triggs, Christopher M.

    2016-01-01

    Cardiac motion is a continuous process; however most measurements to assess cardiac function are taken at brief moments in the cardiac cycle. Using functional data analysis, repeated measurements of left ventricular volume recorded at each frame of a continuous image measured with cardiac ultrasound (echocardiography) were turned into a function of volume over time. The first derivative of the displacement of volume with respect to time is velocity; the second derivative is acceleration. Plotting volume, velocity, and acceleration against each other in a 3-dimensional plot results in a closed loop. The area within the loop is defined by the kinematics of volume change and so may represent ventricular function. • We have developed an approach to analyzing images of the left ventricle that incorporates information from throughout the cardiac cycle. • Comparing systolic and diastolic areas within a loop defined by volume, velocity, and acceleration of left ventricular volume highlights imbalances in the kinematics of the two phases, potentially indicating early sub-clinical disease. • Substantially more information about left ventricular function may be derived from a non-invasive clinically available tool such as echocardiography. PMID:27104150

  17. Percutaneous cardioscopy of the left ventricle in patients with myocarditis

    NASA Astrophysics Data System (ADS)

    Uchida, Yasumi; Tomaru, Takanobu; Nakamura, Fumitaka; Oshima, Tomomitsu; Fujimori, Yoshiharu; Hirose, Junichi

    1992-08-01

    The morphology and function of the cardiac chambers have been evaluated clinically using cineventriculography, computed tomography, magnetic resonance imaging, and endomyocardial biopsy. Excluding the invasive technique of biopsy where tissue is actually removed, these other non-invasive techniques reveal only indirect evidence of endocardial and subendocardial pathology and, therefore, allow the potential for misdiagnosis from insufficient data. Fiberoptic examinations, as recently demonstrated in coronary, pulmonary, and peripheral vessels, allow direct observation of pathology otherwise unobtainable. Recently, similar techniques have been applied to examine the cardiac chambers of dogs and the right heart of humans. In this study, we examine the feasibility and safety of percutaneous fiberoptic cardioscopy of the left ventricle in patients with myocarditis.

  18. Dynamic simulation of chorded mitral valve in a left ventricle using an immersed boundary method

    NASA Astrophysics Data System (ADS)

    Luo, Xiaoyu; Yin, Min; Liang, Chunlei; Wang, Tiejun; Watton, Paul

    2007-11-01

    We use an immersed boundary model to investigate the dynamic behaviour of a chorded mitral prosthesis placed within a left ventricle under physiological flow conditions. In vivo magnetic resonance images of the left ventricle are used to create a numerical ventricle model. The motion of the ventricle model is prescribed during a cardiac cycle. Fluid-structure interaction simulations are carried out to test the performance of the mitral valve in a more realistic physiological environment. These simulations enable us to assess the effect of the ventricle motion, especially its flow vortex structure, on the function of the chorded mitral valve.

  19. Transmural distribution of myocardial infarction: difference between the right and left ventricles in a canine model

    SciTech Connect

    Ohzono, K.; Koyanagi, S.; Urabe, Y.; Harasawa, Y.; Tomoike, H.; Nakamura, M.

    1986-07-01

    The evolution of myocardial infarction 24 hours after ligating both the right coronary artery and the obtuse marginal branch of the left circumflex coronary artery was examined in 33 anesthetized dogs. Postmortem coronary angiography and a tracer microsphere technique were used to determine risk areas and their collateral blood flows, respectively. The mean weight of the risk areas was 11.3 +/- 0.5 g (mean +/- SEM) in the right ventricle and 10.5 +/- 0.9 g in the left ventricle (NS). The weight of infarcted tissue was 5.7 +/- 0.7 g in the right ventricle and 5.2 +/- 0.9 g in the left ventricle (NS). In both ventricles, infarct weight was linearly related to risk area size, and the percent of risk area necrosis was inversely correlated with the extent of collateral flow at 24 hours of coronary ligation, defined as the mean myocardial blood flow inside the central risk area. Ratios of infarct to risk area between the subendocardial and subepicardial layers were 0.76 +/- 0.06 and 0.28 +/- 0.05 in the right and left ventricles, respectively (p less than 0.01, between ventricles, n = 31), which coincided well with subendocardial-to-subepicardial-flow ratios at 24 hours, ie, 0.86 +/- 0.04 in the right ventricle and 0.32 +/- 0.06 in the left ventricle (p less than 0.01). The regional distribution of myocardial infarction correlated well with flow distribution inside the risk area; the slope of these relations was similar between the subendocardium and subepicardium in the right ventricle, whereas in the left ventricle it was larger in the subendocardium than in the subepicardium. Thus, in the dog, the inherent change in the regional distribution of coronary collateral blood flow is an important modifier in the evolution of myocardial infarction, especially in the left ventricle.

  20. Left ventricle wall motion tracking using curvature properties

    NASA Astrophysics Data System (ADS)

    Chandra, Kambhamettu; Goldgof, Dmitry B.

    1992-06-01

    This paper presents the complete implementation of the new algorithm for tracking points on the left ventricle (LV) surface from volumetric cardiac images. We define the local surface stretching as an additional motion parameter of nonrigid transformation. Stretching is constant at all points on the surface for homothetic motion, or follows a polynomial function of certain order (linear in our implementation) in conformal motion. The wall deformation and correspondence information between successive frames of LV in a heart cycle are considered important in evaluating heart behavior and improved diagnosis. We utilize small motion assumption between consecutive frames, hypothesize all possible correspondences, and compute curvature changes for each hypothesis. The computed curvature change is then compared with the one predicted by conformal motion assumption for hypotheses evaluation. We demonstrate the improved performance of the new algorithm utilizing conformal motion with linear stretching assumption over constant stretching assumption on simulated data. Then, the algorithm is applied to real cardiac (CT) images and the stretching of the LV wall is determined. The data set used in our experiments was provided by Dr. Eric Hoffman at University of Pennsylvania Medical school and consists of 16 volumetric (128 by 128 by 118) images taken through the heart cycle.

  1. Measurements, modeling, control and simulation - as applied to the human left ventricle for purposeful physiological monitoring.

    NASA Technical Reports Server (NTRS)

    Ghista, D. N.; Rasmussen, D. N.; Linebarger, R. N.; Sandler, H.

    1971-01-01

    Interdisciplinary engineering research effort in studying the intact human left ventricle has been employed to physiologically monitor the heart and to obtain its 'state-of-health' characteristics. The left ventricle was selected for this purpose because it plays a key role in supplying energy to the body cells. The techniques for measurement of the left ventricular geometry are described; the geometry is effectively displayed to bring out the abnormalities in cardiac function. Methods of mathematical modeling, which make it possible to determine the performance of the intact left ventricular muscle, are also described. Finally, features of a control system for the left ventricle for predicting the effect of certain physiological stress situations on the ventricle performance are discussed.

  2. Quantification of Protein Expression Changes in the Aging Left Ventricle of Rattus norvegicus

    PubMed Central

    Grant, Jennifer E.; Bradshaw, Amy D.; Schwacke, John H.; Baicu, Catalin F.; Zile, Michael R.; Schey, Kevin L.

    2009-01-01

    As the heart ages, electrophysiological and biochemical changes can occur, and the ventricle in many cases loses distensibility, impairing diastolic function. How the proteomic signature of the aged ventricle is unique in comparison to young hearts is still under active investigation. We have undertaken a quantitative proteomics study of aging left ventricles (LVs) utilizing the isobaric Tagging for Relative and Absolute Quantification (iTRAQ) methodology. Differential protein expression was observed for 117 proteins including proteins involved in cell signaling, the immune response, structural proteins, and proteins mediating responses to oxidative stress. For many of these proteins, this is the first report of an association with the aged myocardium. Additionally, two proteins of unknown function were identified. This work serves as the basis for making future comparisons of the aged left ventricle proteome to that of left ventricles obtained from other models of disease and heart failure. PMID:19603826

  3. Recurrent pseudoaneurysm of the left ventricle with subcutaneous herniation into the chest wall. A case report.

    PubMed Central

    Rao, M S; Vaijyanath, P; Taneja, K; Dubey, B; Manchanda, S C; Venugopal, P

    1998-01-01

    Pseudoaneurysm of the left ventricle is rare, and recurrence is extremely rare. We report the case of a 62-year-old man who presented at our hospital with a painless pulsatile swelling in the left breast. He had undergone coronary artery bypass grafting and left-ventricular aneurysmectomy 14 years earlier. On investigation, the swelling was diagnosed to be a pseudoaneurysm of the left ventricle with subcutaneous herniation. The extreme rarity of this condition prompted us to report the case. The investigative techniques and the surgical strategy are discussed. Images PMID:9885110

  4. Patient-specific finite element modeling of the Cardiokinetix Parachute(®) device: effects on left ventricular wall stress and function.

    PubMed

    Lee, Lik Chuan; Ge, Liang; Zhang, Zhihong; Pease, Matthew; Nikolic, Serjan D; Mishra, Rakesh; Ratcliffe, Mark B; Guccione, Julius M

    2014-06-01

    The Parachute(®) (Cardiokinetix, Inc., Menlo Park, California) is a catheter-based device intended to reverse left ventricular (LV) remodeling after antero-apical myocardial infarction. When deployed, the device partitions the LV into upper and lower chambers. To simulate its mechanical effects, we created a finite element LV model based on computed tomography (CT) images from a patient before and 6 months after Parachute(®) implantation. Acute mechanical effects were determined by in silico device implantation (VIRTUAL-Parachute). Chronic effects of the device were determined by adjusting the diastolic and systolic material parameters to better match the 6-month post-implantation CT data and LV pressure data at end-diastole (ED) (POST-OP). Regional myofiber stress and pump function were calculated in each case. The principal finding is that VIRTUAL-Parachute was associated with a 61.2 % reduction in the lower chamber myofiber stress at ED. The POST-OP model was associated with a decrease in LV diastolic stiffness and a larger reduction in myofiber stress at the upper (27.1%) and lower chamber (78.4%) at ED. Myofiber stress at end-systole and stroke volume was little changed in the POST-OP case. These results suggest that the primary mechanism of Parachute(®) is a reduction in ED myofiber stress, which may reverse eccentric post-infarct LV hypertrophy. PMID:24793158

  5. Regional myocardial shape and dimensions of the working isolated canine left ventricle

    NASA Technical Reports Server (NTRS)

    Ritman, E.; Tsuiki, K.; Donald, D.; Wood, E. H.

    1975-01-01

    Angiographic experiments were performed on isolated canine left ventricle preparations using donor dog to supply blood to the coronary circulation via a rotary pump to control coronary flow. The angiographic record was transferred from video tape to video disk for detailed uninterrupted sequential analysis at a frequency of 60 fields/sec. It is shown that the use of a biplane X-ray technique and a metabolically supported isolated canine left ventricle preparation provides an angiographically ideal means of measuring the mechanical dynamics of the myocardium while the intact left ventricular myocardial structure and electrical activation pattern retain most of the in situ ventricular characteristics. In particular, biplane X-ray angiography of the left ventricle can provide estimates of total ventricular function such as ejection fraction, stroke volume, and myocardial mass correct to within 15% under the angiographically ideal conditions of the preparation.

  6. Acute ileofemoral artery thromboembolism due to left ventricle thrombi with spontaneous coronary artery dissection

    PubMed Central

    Jun, Heungman; Jung, Cheol-Woong

    2015-01-01

    Spontaneous coronary artery dissection (SCAD) is a very rare cause of peripheral artery thromboembolism. It is especially rare to show symptoms of acute limb ischemia without chest symptoms during a hospital visit. In this case, a rare case of SCAD led to left heart failure and caused left ventricle thrombi, which in turn caused peripheral thromboembolism. PMID:25553326

  7. Pathomorphology of myocardial circulation: comparative study in increased left or right ventricle afterload.

    PubMed

    Tverskaya, M S; Sukhoparova, V V; Karpova, V V; Raksha, A P; Kadyrova, M K; Abdulkerimova, N Z; Bobrova, N A

    2008-03-01

    Comparative study of pathomorphology of myocardial circulation under conditions of increased afterload of the left or right ventricles showed similar changes. All compartments of the coronary bed were plethoric, capillary blood stasis and perivascular edema, more pronounced in arterial vessels, were detected in both cases. These changes equally involved both ventricles and the ventricular septum. Significant differences consisted in local increase in the density of functioning capillaries. The increase was the maximum in hemodynamically overloaded ventricle and ventricular septum, presumably due to increase of their contractile activity. The density of functioning capillaries in the intact (vs. pressure overloaded) ventricle also increased, but to a lesser degree, which could be due to systemic neurohumoral effects. If increased afterload was complicated by the development of heart failure, circulatory disorders in the myocardium progressed. Significant increase in the density of functioning capillaries in all cardiac compartments indicated decreased vascular tone and exhaustion of coronary reserve. This was paralleled by a sharp arterial plethora in case of increased afterload of the left ventricle and sharp blood stasis in the microcirculatory bed in case of increased right ventricle afterload. Reduction of effective perfusion pressure in the presence of coronary dystonia can cause coronary insufficiency and myocardial ischemia in case of increased right ventricle afterload. PMID:19039949

  8. The Role of Shape and Heart Rate on the Performance of the Left Ventricle.

    PubMed

    Song, Zeying; Borazjani, Iman

    2015-11-01

    The left ventricle function is to pump the oxygenated blood through the circulatory system. Ejection fraction is the main noninvasive parameter for detecting heart disease (healthy >55%), and it is thought to be the main parameter affecting efficiency. However, the effects of other parameters on efficiency have yet to be investigated. We investigate the effect of heart rate and left ventricle shape by carrying out 3D numerical simulations of a left ventricle at different heart rates and perturbed geometries under constant, normal ejection fraction. The simulation using the immersed boundary method provide the 3D flow and pressure fields, which enable direct calculation of a new hemodynamic efficiency (H-efficiency) parameter, which does not depend on any reference pressure. The H-efficiency is defined as the ratio of flux of kinetic energy (useful power) to the total cardiac power into the left ventricle control volume. Our simulations show that H-efficiency is not that sensitive to heart rate but is maximized at around normal heart rate (72 bpm). Nevertheless, it is more sensitive to the shape of the left ventricle, which affects the H-efficiency by as much as 15% under constant ejection fraction. PMID:26312776

  9. Regional myocardial shape and dimensions of the working isolated canine left ventricle

    NASA Technical Reports Server (NTRS)

    Ritman, E. L.; Tsuiki, K.; Donald, D.; Wood, E. H.

    1975-01-01

    The extent to which the dynamic shape and dimensions of the isolated left ventricular myocardial wall differ throughout the myocardium and how these differences are characteristic of the anatomic location was demonstrated. The use of a biplane X-ray technique and a metabolically-supported isolated canine left ventricle preparation provided an angiographically ideal means of measuring mechanical dynamics of the myocardium while the intact left ventricular myocardial structure and electrical activation pattern retains most of the in situ ventricular characteristics.

  10. A new hybrid electro-numerical model of the left ventricle.

    PubMed

    Kozarski, Maciej; Ferrari, Gianfranco; Zieliński, Krzysztof; Górczyńska, Krystyna; Pałko, Krzysztof J; Tokarz, Arkadiusz; Darowski, Marek

    2008-09-01

    The paper presents a new project of a hybrid numerical-physical model of the left ventricle. A physical part of the model can be based on electrical or hydraulic structures. Four variants of the model with numerical and physical heart valves have been designed to investigate an effect of a heart assistance connected in series and in parallel to the natural heart. The LabVIEW real time environment has been used in the model to increase its accuracy and reliability. A prototype of the hybrid electro-numerical model of the left ventricle has been tested in an open loop and closed loop configuration. PMID:18762290

  11. Automatic short axis orientation of the left ventricle in 3D ultrasound recordings

    NASA Astrophysics Data System (ADS)

    Pedrosa, João.; Heyde, Brecht; Heeren, Laurens; Engvall, Jan; Zamorano, Jose; Papachristidis, Alexandros; Edvardsen, Thor; Claus, Piet; D'hooge, Jan

    2016-04-01

    The recent advent of three-dimensional echocardiography has led to an increased interest from the scientific community in left ventricle segmentation frameworks for cardiac volume and function assessment. An automatic orientation of the segmented left ventricular mesh is an important step to obtain a point-to-point correspondence between the mesh and the cardiac anatomy. Furthermore, this would allow for an automatic division of the left ventricle into the standard 17 segments and, thus, fully automatic per-segment analysis, e.g. regional strain assessment. In this work, a method for fully automatic short axis orientation of the segmented left ventricle is presented. The proposed framework aims at detecting the inferior right ventricular insertion point. 211 three-dimensional echocardiographic images were used to validate this framework by comparison to manual annotation of the inferior right ventricular insertion point. A mean unsigned error of 8, 05° +/- 18, 50° was found, whereas the mean signed error was 1, 09°. Large deviations between the manual and automatic annotations (> 30°) only occurred in 3, 79% of cases. The average computation time was 666ms in a non-optimized MATLAB environment, which potentiates real-time application. In conclusion, a successful automatic real-time method for orientation of the segmented left ventricle is proposed.

  12. Unusual Clinical Presentation of a Giant Left Ventricle Hydatid Cyst

    PubMed Central

    Alizadeh-Ghavidel, Alireza; Kyavar, Majid; Sadeghpour, Anita; Totonchi, Zia; Mirmesdagh, Yalda; Almassi, Nooshin; Madadi, Shabnam

    2013-01-01

    A 39-year-old woman was hospitalized in our center due to chest and left shoulder pain. Having a history of tamponade and tuberculosis, she was under treatment for the previous two months. Echocardiography, chest CT and MRI documented intramyocardial and pericardial hydatid cyst which was later confirmed by further pathological studies. Later, the cyst was removed surgically. PMID:24404351

  13. Automatic finite element generators

    NASA Technical Reports Server (NTRS)

    Wang, P. S.

    1984-01-01

    The design and implementation of a software system for generating finite elements and related computations are described. Exact symbolic computational techniques are employed to derive strain-displacement matrices and element stiffness matrices. Methods for dealing with the excessive growth of symbolic expressions are discussed. Automatic FORTRAN code generation is described with emphasis on improving the efficiency of the resultant code.

  14. Effect of diastolic flow patterns on the function of the left ventricle

    NASA Astrophysics Data System (ADS)

    Seo, Jung Hee; Mittal, Rajat

    2013-11-01

    Direct numerical simulations are used to study the effect of intraventricular flow patterns on the pumping efficiency and the blood mixing and transport characteristics of the left ventricle. The simulations employ a geometric model of the left ventricle which is derived from contrast computed tomography. A variety of diastolic flow conditions are generated for a fixed ejection fraction in order to delineate the effect of flow patterns on ventricular performance. The simulations indicate that the effect of intraventricular blood flow pattern on the pumping power is physiologically insignificant. However, diastolic flow patterns have a noticeable effect on the blood mixing as well as the residence time of blood cells in the ventricle. The implications of these findings on ventricular function are discussed.

  15. A numerical study of the left ventricle using structure-based bio-mechanical model

    NASA Astrophysics Data System (ADS)

    Zhu, Yunfei; Luo, Xiaoyu; Feng, Yaoqi

    A numerical study of the left ventricle using structure-based bio-mechanical model In space environment, microgravity and radiation can have deleterious effects on the cardiovascular system of the astronauts. The work in this paper is part of an ongoing effort to use mathematical models to provide a better understanding of the impact of long-duration spaceflight on the heart and blood vessels. In this study, we develop a computational left ventricle model before and after myocardium infarction based on cardiovascular mechanical theory. The anatomically realistic model has a rule-based fibre structure and a orthotropic structure-based constitutive model. The differences of deformations in the left ventricle before and after infarction are compared in details. In particular, the effects of fiber direction and fiber dispersion are examined. The disarray of both the fiber and sheet orientation is characterized by a dispersion parameter. The left ventricle volume is calculated from the MRI images and used for the optimization of the parameters of the myocardium. We provide the numerical framework for further study on effects of spaceflight on the cardiovascular system.

  16. [The index of left ventricle dilatation estimated with echocardiography in infarct patients].

    PubMed

    Scotta di Quacquaro, G; Punzi, M; Franciulli, V

    1981-03-31

    The Authors have introduced, for functional valuation of the left ventricle in infarcted patients, an echocardiographic new parameter: the index of dilatation (ID). This index constantly show oneself increased in all infarcted patients that clinically show marks of the cardiac decompensation, also when the Vcf and Fe show modest alterations. According to the Authors, the ID have in report with the PTDVS and constitute and important evidence of the left ventricular working controllable in the time. PMID:6452589

  17. A Computational Chemo-Fluidic Modeling for the Investigation of Patient-Specific Left Ventricle Thrombogenesis

    NASA Astrophysics Data System (ADS)

    Mittal, Rajat; Seo, Jung Hee; Abd, Thura; George, Richard T.

    2015-11-01

    Patients recovering from myocardial infarction (MI) are considered at high-risk for cardioembolic stroke due to the formation of left ventricle thrombus (LVT). The formation of LVT is the result of a complex interplay between the fluid dynamics inside the ventricle and the chemistry of coagulation, and the role of LV flow pattern on the thrombogenesis was not well understood. The previous computational study performed with the model ventricles suggested that the local flow residence time is the key variable governing the accumulation of coagulation factors. In the present study, a coupled, chemo-fluidic computational modeling is applied to the patient-specific cases of infracted ventricles to investigate the interaction between the LV hemodynamics and thrombogensis. In collaboration with the Johns Hopkins hospital, patient-specific LV models are constructed using the multi-modality medical imaging data. Blood flow in the left ventricle is simulated by solving the incompressible Navier-Stokes equations and the biochemical reactions for the thrombus formation are modeled with convection-diffusion-reaction equations. The formation and deposition of key coagulation chemical factors are then correlated with the hemodynamic flow metrics to explore the biophysics underlying LVT risk. Supported by the Johns Hopkins Medicine Discovery Fund and NSF Grant: CBET-1511200, Computational resource by XSEDE NSF grant TG-CTS100002.

  18. Multiple Small Coronary Artery Fistulas Emptying into the Left Ventricle: A Rare but Challenging Problem

    PubMed Central

    Kahaly, Omar

    2016-01-01

    A coronary artery fistula (CAF) is an abnormal communication between a coronary artery and a cardiac chamber or a great vessel. CAFs are rare based on coronary arteriography and when found they most often empty into the right ventricle and atrium and less often into the high pressure, low compliance left ventricle (LV). A patient who presented with atypical chest pain and was found to have multiple small CAFs originating from the ramus intermedius coronary artery and emptying into the LV is presented. This case highlights the challenges in providing an appropriate therapy for multiple small CAFs emptying into the LV. PMID:27525009

  19. Automated Axial Right Ventricle to Left Ventricle Diameter Ratio Computation in Computed Tomography Pulmonary Angiography

    PubMed Central

    Rodríguez-López, Sara; Kumamaru, Kanako K.; George, Elizabeth; San José Estépar, Raúl; Rybicki, Frank J.; Ledesma-Carbayo, Maria J.

    2015-01-01

    Background and Purpose Right Ventricular to Left Ventricular (RV/LV) diameter ratio has been shown to be a prognostic biomarker for patients suffering from acute Pulmonary Embolism (PE). While Computed Tomography Pulmonary Angiography (CTPA) images used to confirm a clinical suspicion of PE do include information of the heart, a numerical RV/LV diameter ratio is not universally reported, likely because of lack in training, inter-reader variability in the measurements, and additional effort by the radiologist. This study designs and validates a completely automated Computer Aided Detection (CAD) system to compute the axial RV/LV diameter ratio from CTPA images so that the RV/LV diameter ratio can be a more objective metric that is consistently reported in patients for whom CTPA diagnoses PE. Materials and Methods The CAD system was designed specifically for RV/LV measurements. The system was tested in 198 consecutive CTPA patients with acute PE. Its accuracy was evaluated using reference standard RV/LV radiologist measurements and its prognostic value was established for 30-day PE-specific mortality and a composite outcome of 30-day PE-specific mortality or the need for intensive therapies. The study was Institutional Review Board (IRB) approved and HIPAA compliant. Results The CAD system analyzed correctly 92.4% (183/198) of CTPA studies. The mean difference between automated and manually computed axial RV/LV ratios was 0.03±0.22. The correlation between the RV/LV diameter ratio obtained by the CAD system and that obtained by the radiologist was high (r=0.81). Compared to the radiologist, the CAD system equally achieved high accuracy for the composite outcome, with areas under the receiver operating characteristic curves of 0.75 vs. 0.78. Similar results were found for 30-days PE-specific mortality, with areas under the curve of 0.72 vs. 0.75. Conclusions An automated CAD system for determining the CT derived RV/LV diameter ratio in patients with acute PE has high

  20. Finite Element Analysis Code

    Energy Science and Technology Software Center (ESTSC)

    2006-03-08

    MAPVAR-KD is designed to transfer solution results from one finite element mesh to another. MAPVAR-KD draws heavily from the structure and coding of MERLIN II, but it employs a new finite element data base, EXODUS II, and offers enhanced speed and new capabilities not available in MERLIN II. In keeping with the MERLIN II documentation, the computational algorithms used in MAPVAR-KD are described. User instructions are presented. Example problems are included to demonstrate the operationmore » of the code and the effects of various input options. MAPVAR-KD is a modification of MAPVAR in which the search algorithm was replaced by a kd-tree-based search for better performance on large problems.« less

  1. The Impact of Obesity on the Left Ventricle

    PubMed Central

    Turkbey, Evrim B.; McClelland, Robyn L.; Kronmal, Richard A.; Burke, Gregory L.; Bild, Diane E.; Tracy, Russell P.; Arai, Andrew E.; Lima, João A. C.; Bluemke, David A.

    2011-01-01

    OBJECTIVES The purpose of this study was to evaluate the relationship of left ventricular (LV) remodeling assessed by cardiac magnetic resonance to various measures of obesity in a large population-based study. BACKGROUND Obesity is a well-known risk factor for cardiovascular disease, yet its relationship with LV size and function is poorly understood. METHODS A total of 5,098 participants (age 45 to 84 years; 48% men) in the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent cardiovascular disease underwent cardiac magnetic resonance to assess LV size and function as well as measures of obesity, including body mass index, waist-to-hip ratio and waist circumference, and cardiovascular risk factors. Fat mass (FM) was estimated based on height-weight models derived from bioelectrical impedance studies. The associations of obesity measures with LV size and function were evaluated using linear spline regression models for body mass index and multivariable regression models for other measures of obesity; they were displayed graphically using generalized additive models. RESULTS LV mass and end-diastolic volume were positively associated with measures of obesity in both sexes after adjustment for risk factors (e.g., 5.7-g and 6.9-g increase in LV mass per 10-kg increase in FM in women and men, respectively [p < 0.001]). LV mass-to-volume ratio was positively associated with increased body mass index, waist-to-hip ratio, waist circumference, and estimated FM (e.g., 0.02-g/ml and 0.06-g/ml increase in mass-to-volume ratio per 10-kg increase in FM in women and men, respectively [p < 0.001]). The increased mass-to-volume ratio was due to a greater increase in LV mass relative to LV end-diastolic volume. All associations were stronger for men than for women. Ejection fraction showed no significant association with measures of obesity. CONCLUSIONS Obesity was associated with concentric LV remodeling without change in ejection fraction in a large

  2. Structure-based finite strain modelling of the human left ventricle in diastole.

    PubMed

    Wang, H M; Gao, H; Luo, X Y; Berry, C; Griffith, B E; Ogden, R W; Wang, T J

    2013-01-01

    Finite strain analyses of the left ventricle provide important information on heart function and have the potential to provide insights into the biomechanics of myocardial contractility in health and disease. Systolic dysfunction is the most common cause of heart failure; however, abnormalities of diastolic function also contribute to heart failure, and are associated with conditions including left ventricular hypertrophy and diabetes. The clinical significance of diastolic abnormalities is less well understood than systolic dysfunction, and specific treatments are presently lacking. To obtain qualitative and quantitative information on heart function in diastole, we develop a three-dimensional computational model of the human left ventricle that is derived from noninvasive imaging data. This anatomically realistic model has a rule-based fibre structure and a structure-based constitutive model. We investigate the sensitivity of this comprehensive model to small changes in the constitutive parameters and to changes in the fibre distribution. We make extensive comparisons between this model and similar models that employ different constitutive models, and we demonstrate qualitative and quantitative differences in stress and strain distributions for the different constitutive models. We also provide an initial validation of our model through comparisons to experimental data on stress and strain distributions in the left ventricle. PMID:23293070

  3. Finite Element Analysis Code

    Energy Science and Technology Software Center (ESTSC)

    2005-05-07

    CONEX is a code for joining sequentially in time multiple exodusll database files which all represent the same base mesh topology and geometry. It is used to create a single results or restart file from multiple results or restart files which typically arise as the result of multiple restarted analyses. CONEX is used to postprocess the results from a series of finite element analyses. It can join sequentially the data from multiple results databases intomore » a single database which makes it easier to postprocess the results data.« less

  4. Finite Element Analysis Code

    Energy Science and Technology Software Center (ESTSC)

    2005-06-26

    Exotxt is an analysis code that reads finite element results data stored in an exodusII file and generates a file in a structured text format. The text file can be edited or modified via a number of text formatting tools. Exotxt is used by analysis to translate data from the binary exodusII format into a structured text format which can then be edited or modified and then either translated back to exodusII format or tomore » another format.« less

  5. 3D Segmentation of the Left Ventricle Combining Long- and Shortaxis Views

    NASA Astrophysics Data System (ADS)

    Relan, Jatin; Säring, Dennis; Groth, Michael; Müllerleile, Kai; Handels, Heinz

    Segmentation of the left ventricle (LV) is required to quantify LV remodeling after myocardial infarction. Therefore spatiotemporal Cine MR sequences including longaxis and shortaxis images are acquired. In this paper a new segmentation method for fast and robust segmentation of the left ventricle is presented. The new approach considers the position of the mitral valve and the apex as well as the longaxis contours to generate a 3D LV surface model. The segmentation result can be checked and adjusted in the shortaxis images. Finally quantitative parameters were extracted. For evaluation the LV was segmented in eight datasets of the same subject by two medical experts using a contour drawing tool and the new segmentation tool. The results of both methods were compared concerning interaction time and intra- and interobserver variance. The presented segmentation method proved to be fast. The intra- and interobserver variance is decreased for all extracted parameters.

  6. Pseudoaneurysm of the free wall of the left ventricle without obstruction of major coronary arteries.

    PubMed

    Tesler, U F; Leccese, A

    1996-01-01

    We report a case of a 63-year-old woman who presented with pseudoaneurysm of the free wall of the left ventricle secondary to myocardial infarction, in the presence of angiographically normal major coronary arteries. This is the only such case we know of, in which the patient underwent successful surgical correction. At last follow-up, the patient was in good condition with no evidence of cardiac disease, at 9 years after surgery. PMID:8680277

  7. Traumatic Left Anterior Descending Coronary Artery-Right Ventricle Fistula: A Case Report

    PubMed Central

    Sheikhi, Mohammad Ali; Asgari, Mehdi; Firouzabadi, Mehdi Dehghani; Zeraati, Mohammad Reza; Rezaee, Alireza

    2011-01-01

    Traumatic coronary artery-cameral fistulas (TCAF) are rare and may present secondary to penetrating injuries (80%) or iatrogenic traumas. Early operative intervention remains the recommended treatment modality for accidental traumatic coronary artery fistulas. We report the case of a 17-year-old man who presented with left anterior descending coronary artery-right ventricle fistula following penetrating cardiac trauma, which was successfully repaired surgically. PMID:23074613

  8. Ghost in the left ventricle on electrocardiogram-gated cardiac computed tomography by turbulent flow.

    PubMed

    Byun, Sung Su; Sung, Yon Mi; Lee, Kyounghoon; Kim, Yoon Kyung; Park, Jae Hyung

    2015-01-01

    We report on an extremely rare case of a fake lesion in the left ventricle on electrocardiogram-gated cardiac computed tomography simulating thrombus or tumor by turbulent flow in a 14-year-old boy. Cardiac magnetic resonance imaging with contrast-enhanced myocardial perfusion and delayed enhancement images were helpful in excluding true thrombus or tumor. Awareness of this potential pitfall is critical in order to avoid unnecessary anticoagulation or surgery. PMID:25229204

  9. Idiopathic dilated cardiomyopathy: computerized anatomic study of relashionship between septal and free left ventricle wall

    PubMed Central

    Juliani, Paulo Sérgio; da Costa, Éder França; Correia, Aristides Tadeu; Monteiro, Rosangela; Jatene, Fabio Biscegli

    2014-01-01

    Introduction A feature of dilated cardiomyopathy is the deformation of ventricular cavity, which contributes to systolic dysfunction. Few studies have evaluated this deformation bearing in mind ventricular regions and segments of the ventricle, which could reveal important details of the remodeling process, supporting a better understanding of its role in functional impairment and the development of new therapeutic strategies. Objective To evaluate if, in basal, equatorial and apical regions, increased internal transverse perimeter of left ventricle in idiopathic dilated cardiomyopathy occurs proportionally between the septal and non-septal segment. Methods We performed an anatomical study with 28 adult hearts from human cadavers. One group consisted of 18 hearts with idiopathic dilated cardiomyopathy and another group with 10 normal hearts. After lamination and left ventricle digital image capture, in three different regions (base, equator and apex), the transversal internal perimeter of left ventricle was divided into two segments: septal and not septal. These segments were measured by proper software. It was established an index of proportionality between these segments, called septal and non-septal segment index. Then we determined whether this index was the same in both groups. Results Among patients with normal hearts and idiopathic dilated cardiomyopathy, the index of proportionality between the two segments (septal and non-septal) showed no significant difference in the three regions analyzed. The comparison results of the indices NSS/SS among normal and enlarged hearts were respectively: in base 1.99 versus 1.86 (P=0.46), in equator 2.22 versus 2.18 (P=0.79) and in apex 2.96 versus 3.56 (P=0.11). Conclusion In the idiopathic dilated cardiomyopathy, the transversal dilatation of left ventricular internal perimeter occurs proportionally between the segments corresponding to the septum and free wall at the basal, equatorial and apical regions of this chamber

  10. Pseudoaneurysm of the free wall of the left ventricle without obstruction of major coronary arteries.

    PubMed Central

    Tesler, U F; Leccese, A

    1996-01-01

    We report a case of a 63-year-old woman who presented with pseudoaneurysm of the free wall of the left ventricle secondary to myocardial infarction, in the presence of angiographically normal major coronary arteries. This is the only such case we know of, in which the patient underwent successful surgical correction. At last follow-up, the patient was in good condition with no evidence of cardiac disease, at 9 years after surgery. Images PMID:8680277

  11. Computational modeling and analysis for left ventricle motion using CT/Echo image fusion

    NASA Astrophysics Data System (ADS)

    Kim, Ji-Yeon; Kang, Nahyup; Lee, Hyoung-Euk; Kim, James D. K.

    2014-03-01

    In order to diagnose heart disease such as myocardial infarction, 2D strain through the speckle tracking echocardiography (STE) or the tagged MRI is often used. However out-of-plane strain measurement using STE or tagged MRI is inaccurate. Therefore, strain for whole organ which are analyzed by simulation of 3D cardiac model can be applied in clinical diagnosis. To simulate cardiac contraction in a cycle, cardiac physical properties should be reflected in cardiac model. The myocardial wall in left ventricle is represented as a transversely orthotropic hyperelastic material, with the fiber orientation varying sequentially from the epicardial surface, through about 0° at the midwall, to the endocardial surface. A time-varying elastance model is simulated to contract myocardial fiber, and physiological intraventricular systolic pressure curves are employed for the cardiac dynamics simulation in a cycle. And an exact description of the cardiac motion should be acquired in order that essential boundary conditions for cardiac simulation are obtained effectively. Real time cardiac motion can be acquired by using echocardiography and exact cardiac geometrical 3D model can be reconstructed using 3D CT data. In this research, image fusion technology from CT and echocardiography is employed in order to consider patient-specific left ventricle movement. Finally, longitudinal strain from speckle tracking echocardiography which is known to fit actual left ventricle deformation relatively well is used to verify these results.

  12. Fluid Structure Interaction simulation of heart prosthesis in patient-specific left-ventricle/aorta anatomies

    NASA Astrophysics Data System (ADS)

    Le, Trung; Borazjani, Iman; Sotiropoulos, Fotis

    2009-11-01

    In order to test and optimize heart valve prosthesis and enable virtual implantation of other biomedical devices it is essential to develop and validate high-resolution FSI-CFD codes for carrying out simulations in patient-specific geometries. We have developed a powerful numerical methodology for carrying out FSI simulations of cardiovascular flows based on the CURVIB approach (Borazjani, L. Ge, and F. Sotiropoulos, Journal of Computational physics, vol. 227, pp. 7587-7620 2008). We have extended our FSI method to overset grids to handle efficiently more complicated geometries e.g. simulating an MHV implanted in an anatomically realistic aorta and left-ventricle. A compliant, anatomic left-ventricle is modeled using prescribed motion in one domain. The mechanical heart valve is placed inside the second domain i.e. the body-fitted curvilinear mesh of the anatomic aorta. The simulations of an MHV with a left-ventricle model underscore the importance of inflow conditions and ventricular compliance for such simulations and demonstrate the potential of our method as a powerful tool for patient-specific simulations.

  13. Effect of trabeculae and papillary muscles on the hemodynamics of the left ventricle

    NASA Astrophysics Data System (ADS)

    Vedula, Vijay; Seo, Jung-Hee; Lardo, Albert C.; Mittal, Rajat

    2016-04-01

    The impact of surface trabeculae and papillary muscles on the hemodynamics of the left ventricle (LV) is investigated using numerical simulations. Simulations of ventricular flow are conducted for two different models of the LV derived from high-resolution cardiac computed tomography (CT) scans using an immersed boundary method-based flow solver. One model comprises a trabeculated left ventricle (TLV) that includes both trabeculae and papillary muscles, while the second model has a smooth left ventricle that is devoid of any of these surface features. Results indicate that the trabeculae and papillary muscles significantly disrupt the vortices that develop during early filling in the TLV model. Large recirculation zones are found to form in the wake of the papillary muscles; these zones enhance the blockage provided by the papillary muscles and create a path for the mitral jet to penetrate deeper into the ventricular apex during diastole. During systole, the trabeculae enhance the apical washout by `squeezing' the flow from the apical region. Finally, the trabeculae enhance viscous dissipation rate of the ventricular flow, but this effect is not significant in the overall power budget.

  14. [Research of Left Ventricle Function Analysis Using Real-time Cardiac Magnetic Resonance Imaging].

    PubMed

    Yang, Fan; He, Yan; Zhang, Jie; Wu, Yin

    2015-12-01

    Real-time free breathing cardiac cine imaging is a reproducible method with shorter acquisition time and without breath-hold for cardiac magnetic resonance imaging. However, the detection of end-diastole and end-systole frames of real-time free breathing cardiac cine imaging for left ventricle function analysis is commonly completed by visual identification, which is time-consuming and laborious. In order to save processing time, we propose a method for semi-automatic identification of end-diastole and end-systole frames. The method fits respiratory motion signal and acquires the expiration phase, end-diastole and end-systole frames by cross correlation coefficient. The procedure successfully worked on ten healthy volunteers and validated by the analysis of left ventricle function compared to the standard breath-hold steady-state free precession cardiac cine imaging without any significant statistical differences. The results demonstrated that the present method could correctly detect end-diastole and end-systole frames. In the future, this technique may be used for rapid left ventricle function analysis in clinic. PMID:27079101

  15. Right Ventricular Outflow Tract Tachycardia with Structural Abnormalities of the Right Ventricle and Left Ventricular Diverticulum

    PubMed Central

    Martini, Bortolo; Trevisi, Nicola; Martini, Nicolò; Zhang, Li

    2015-01-01

    A 43-year-old woman presented to the emergency room with a sustained ventricular tachycardia (VT). ECG showed a QRS in left bundle branch block morphology with inferior axis. Echocardiography, ventricular angiography, and cardiac magnetic resonance imaging (CMRI) revealed a normal right ventricle and a left ventricular diverticulum. Electrophysiology studies with epicardial voltage mapping identified a large fibrotic area in the inferolateral layer of the right ventricular wall and a small area of fibrotic tissue at the anterior right ventricular outflow tract. VT ablation was successfully performed with combined epicardial and endocardial approaches. PMID:26509086

  16. A robust automated left ventricle region of interest localization technique using a cardiac cine MRI atlas

    NASA Astrophysics Data System (ADS)

    Ben-Zikri, Yehuda Kfir; Linte, Cristian A.

    2016-03-01

    Region of interest detection is a precursor to many medical image processing and analysis applications, including segmentation, registration and other image manipulation techniques. The optimal region of interest is often selected manually, based on empirical knowledge and features of the image dataset. However, if inconsistently identified, the selected region of interest may greatly affect the subsequent image analysis or interpretation steps, in turn leading to incomplete assessment during computer-aided diagnosis or incomplete visualization or identification of the surgical targets, if employed in the context of pre-procedural planning or image-guided interventions. Therefore, the need for robust, accurate and computationally efficient region of interest localization techniques is prevalent in many modern computer-assisted diagnosis and therapy applications. Here we propose a fully automated, robust, a priori learning-based approach that provides reliable estimates of the left and right ventricle features from cine cardiac MR images. The proposed approach leverages the temporal frame-to-frame motion extracted across a range of short axis left ventricle slice images with small training set generated from les than 10% of the population. This approach is based on histogram of oriented gradients features weighted by local intensities to first identify an initial region of interest depicting the left and right ventricles that exhibits the greatest extent of cardiac motion. This region is correlated with the homologous region that belongs to the training dataset that best matches the test image using feature vector correlation techniques. Lastly, the optimal left ventricle region of interest of the test image is identified based on the correlation of known ground truth segmentations associated with the training dataset deemed closest to the test image. The proposed approach was tested on a population of 100 patient datasets and was validated against the ground truth

  17. Probabilistic fracture finite elements

    NASA Technical Reports Server (NTRS)

    Liu, W. K.; Belytschko, T.; Lua, Y. J.

    1991-01-01

    The Probabilistic Fracture Mechanics (PFM) is a promising method for estimating the fatigue life and inspection cycles for mechanical and structural components. The Probability Finite Element Method (PFEM), which is based on second moment analysis, has proved to be a promising, practical approach to handle problems with uncertainties. As the PFEM provides a powerful computational tool to determine first and second moment of random parameters, the second moment reliability method can be easily combined with PFEM to obtain measures of the reliability of the structural system. The method is also being applied to fatigue crack growth. Uncertainties in the material properties of advanced materials such as polycrystalline alloys, ceramics, and composites are commonly observed from experimental tests. This is mainly attributed to intrinsic microcracks, which are randomly distributed as a result of the applied load and the residual stress.

  18. A Reconstruction Method of Blood Flow Velocity in Left Ventricle Using Color Flow Ultrasound

    PubMed Central

    Jang, Jaeseong; Ahn, Chi Young; Jeon, Kiwan; Heo, Jung; Lee, DongHak; Choi, Jung-il

    2015-01-01

    Vortex flow imaging is a relatively new medical imaging method for the dynamic visualization of intracardiac blood flow, a potentially useful index of cardiac dysfunction. A reconstruction method is proposed here to quantify the distribution of blood flow velocity fields inside the left ventricle from color flow images compiled from ultrasound measurements. In this paper, a 2D incompressible Navier-Stokes equation with a mass source term is proposed to utilize the measurable color flow ultrasound data in a plane along with the moving boundary condition. The proposed model reflects out-of-plane blood flows on the imaging plane through the mass source term. The boundary conditions to solve the system of equations are derived from the dimensions of the ventricle extracted from 2D echocardiography data. The performance of the proposed method is evaluated numerically using synthetic flow data acquired from simulating left ventricle flows. The numerical simulations show the feasibility and potential usefulness of the proposed method of reconstructing the intracardiac flow fields. Of particular note is the finding that the mass source term in the proposed model improves the reconstruction performance. PMID:26078773

  19. Mathematical model of the anatomy and fibre orientation field of the left ventricle of the heart

    PubMed Central

    2013-01-01

    Background One of the main factors affecting propagation of electrical waves and contraction in ventricles of the heart is anisotropy of cardiac tissue. Anisotropy is determined by orientation of myocardial fibres. Determining fibre orientation field and shape of the heart is important for anatomically accurate modelling of electrical and mechanical function of the heart. The aim of this paper is to introduce a theoretical rule-based model for anatomy and fibre orientation of the left ventricle (LV) of the heart and to compare it with experimental data. We suggest explicit analytical formulae that allow us to obtain the left ventricle form and its fibre direction field. The ventricle band concept of cardiac architecture given by Torrent-Guasp is chosen as the model postulate. Methods In our approach, anisotropy of the heart is derived from some general principles. The LV is considered as a set of identical spiral surfaces, each of which can be produced from the other by rotation around one vertical axis. Each spiral surface is filled with non-intersecting curves which represent myocardial fibres. For model verification, we use experimental data on fibre orientation in human and canine hearts. Results LV shape and anisotropy are represented by explicit analytical expressions in a curvilinear 3-D coordinate system. The derived fibre orientation field shows good qualitative agreement with experimental data. The model reveals the most thorough quantitative simulation of fibre angles at the LV middle zone. Conclusions Our analysis shows that the band concept can generate realistic anisotropy of the LV. Our model shows good qualitative agreement between the simulated fibre orientation field and the experimental data on LV anisotropy, and the model can be used for various numerical simulations to study the effects of anisotropy on cardiac excitation and mechanical function. PMID:23773421

  20. NOTE: A cooled intraesophageal balloon to prevent thermal injury during endocardial surgical radiofrequency ablation of the left atrium: a finite element study

    NASA Astrophysics Data System (ADS)

    Berjano, Enrique J.; Hornero, Fernando

    2005-10-01

    Recent clinical studies on intraoperative monopolar radiofrequency ablation of atrial fibrillation have reported some cases of injury to the esophagus. The aim of this study was to perform computer simulations using three-dimensional finite element models in order to investigate the feasibility of a cooled intraesophageal balloon appropriately placed to prevent injury. The models included atrial tissue and a fragment of esophagus and lung linked by connective tissue. The lesion depth in the esophagus was assessed using a 50 °C isotherm and expressed as a percentage of thickness of the esophageal wall. The results are as follows: (1) chilling the esophagus by means of a cooled balloon placed in the lumen minimizes the lesion in the esophageal wall compared to the cases in which no balloon is used (a collapsed esophagus) and with a non-cooled balloon; (2) the temperature of the cooling fluid has a more significant effect on the minimization of the lesion than the rate of cooling (the thermal transfer coefficient for forced convection); and (3) pre-cooling periods previous to RF ablation do not represent a significant improvement. Finally, the results also suggest that the use of a cooled balloon could affect the transmurality of the atrial lesion, especially in the cases where the atrium is of considerable thickness.

  1. Scaling of left ventricle cardiomyocyte ultrastructure across development in the kangaroo Macropus fuliginosus.

    PubMed

    Snelling, Edward P; Taggart, David A; Maloney, Shane K; Farrell, Anthony P; Leigh, Christopher M; Waterhouse, Lyn; Williams, Ruth; Seymour, Roger S

    2015-06-01

    The heart and left ventricle of the marsupial western grey kangaroo Macropus fuliginosus exhibit biphasic allometric growth, whereby a negative shift in the trajectory of cardiac growth occurs at pouch exit. In this study, we used transmission electron microscopy to examine the scaling of left ventricle cardiomyocyte ultrastructure across development in the western grey kangaroo over a 190-fold body mass range (0.355-67.5 kg). The volume-density (%) of myofibrils, mitochondria, sarcoplasmic reticuli and T-tubules increase significantly during in-pouch growth, such that the absolute volume (ml) of these organelles scales with body mass (Mb; kg) with steep hyperallometry: 1.41Mb (1.38), 0.64Mb (1.29), 0.066Mb (1.45) and 0.035Mb (1.87), respectively. Maturation of the left ventricle ultrastructure coincides with pouch vacation, as organelle volume-densities scale independent of body mass across post-pouch development, such that absolute organelle volumes scale in parallel and with relatively shallow hypoallometry: 4.65Mb (0.79), 1.75Mb (0.77), 0.21Mb (0.79) and 0.35Mb (0.79), respectively. The steep hyperallometry of organelle volumes and volume-densities across in-pouch growth is consistent with the improved contractile performance of isolated cardiac muscle during fetal development in placental mammals, and is probably critical in augmenting cardiac output to levels necessary for endothermy and independent locomotion in the young kangaroo as it prepares for pouch exit. The shallow hypoallometry of organelle volumes during post-pouch growth suggests a decrease in relative cardiac requirements as body mass increases in free-roaming kangaroos, which is possibly because the energy required for hopping is independent of speed, and the capacity for energy storage during hopping could increase as the kangaroo grows. PMID:25908057

  2. Fat infiltration of left ventricle - a rare cause of sudden cardiac death.

    PubMed

    Kanchan, Tanuj; Acharya, Jenash; Ram, Pradhum; Khadilkar, Urmila N; Rana, Talvinder

    2016-09-01

    Cor adiposum is a rare disorder of the heart, where the normal heart tissue is replaced by fibro-fatty infiltrates. We report one such case of a middle-aged female who was declared dead shortly after a syncopal episode. At autopsy, the pericardium was intact and firmly adhered to the heart. Histopathology revealed fatty infiltrates extending into the left ventricle of the heart. A post-mortem diagnosis of Cor adiposum was made which is an uncommonly reported cause of sudden cardiac death. PMID:26975397

  3. Level set algorithms comparison for multi-slice CT left ventricle segmentation

    NASA Astrophysics Data System (ADS)

    Medina, Ruben; La Cruz, Alexandra; Ordoñes, Andrés.; Pesántez, Daniel; Morocho, Villie; Vanegas, Pablo

    2015-12-01

    The comparison of several Level Set algorithms is performed with respect to 2D left ventricle segmentation in Multi-Slice CT images. Five algorithms are compared by calculating the Dice coefficient between the resulting segmentation contour and a reference contour traced by a cardiologist. The algorithms are also tested on images contaminated with Gaussian noise for several values of PSNR. Additionally an algorithm for providing the initialization shape is proposed. This algorithm is based on a combination of mathematical morphology tools with watershed and region growing algorithms. Results on the set of test images are promising and suggest the extension to 3{D MSCT database segmentation.

  4. Segmentation of the Left Ventricle in Myocardial Perfusion SPECT Using Active Shape Model

    NASA Astrophysics Data System (ADS)

    Tan, Wooi-Haw; Besar, Rosli

    In the quantification of myocardial perfusion SPECT (MPS), numerous processes are involved. Automation is desired as it will considerably reduce the laboriousness of the underlying tasks. In this paper, we propose a segmentation scheme for the delineation of left ventricle (LV) using the Active Shape Models. Our scheme will reduce the labour-intensiveness in MPS quantification, while still allowing interactive guidance from the medical experts. The proposed scheme has been applied on clinical MPS tomograms in which it has successfully delineated the LV in 94% of the test data. In addition, it has also shown to be more suitable for LV segmentation than the rivaling Active Contour Model.

  5. Oxygen utilization of the human left ventricle - An indirect method for its evaluation and clinical considerations

    NASA Technical Reports Server (NTRS)

    Ghista, D. N.; Sandler, H.

    1974-01-01

    An analytical method is presented for determining the oxygen consumption rate of the intact heart working (as opposed to empty but beating) human left ventricle. Use is made of experimental recordings obtained for the chamber pressure and the associated dimensions of the LV. LV dimensions are determined by cineangiocardiography, and the chamber pressure is obtained by means of fluid-filled catheters during retrograde or transeptal catheterization. An analytical method incorporating these data is then employed for the evaluation of the LV coronary oxygen consumption in five subjects. Oxygen consumption for these subjects was also obtained by the conventional clinical method in order to evaluate the reliability of the proposed method.

  6. Three-dimensional structure of the flow inside the left ventricle of the human heart

    NASA Astrophysics Data System (ADS)

    Fortini, S.; Querzoli, G.; Espa, S.; Cenedese, A.

    2013-11-01

    The laboratory models of the human heart left ventricle developed in the last decades gave a valuable contribution to the comprehension of the role of the fluid dynamics in the cardiac function and to support the interpretation of the data obtained in vivo. Nevertheless, some questions are still opened and new ones stem from the continuous improvements in the diagnostic imaging techniques. Many of these unresolved issues are related to the three-dimensional structure of the left ventricular flow during the cardiac cycle. In this paper, we investigated in detail this aspect using a laboratory model. The ventricle was simulated by a flexible sack varying its volume in time according to a physiologically shaped law. Velocities measured during several cycles on series of parallel planes, taken from two orthogonal points of view, were combined together in order to reconstruct the phase-averaged, three-dimensional velocity field. During the diastole, three main steps are recognized in the evolution of the vortical structures: (1) straight propagation in the direction of the long axis of a vortex ring originated from the mitral orifice; (2) asymmetric development of the vortex ring on an inclined plane; and (3) single vortex formation. The analysis of three-dimensional data gives the experimental evidence of the reorganization of the flow in a single vortex persisting until the end of the diastole. This flow pattern seems to optimize the cardiac function since it directs velocity towards the aortic valve just before the systole and minimizes the fraction of blood residing within the ventricle for more cycles.

  7. Characterization of human left ventricle flow patterns using ultrasound and Lagrangian coherent structures

    NASA Astrophysics Data System (ADS)

    Hendabadi, Sahar; Del Alamo, Juan Carlos; Benito, Yolanda; Yotti, Raquel; Bermejo, Javier; Shadden, Shawn

    2012-11-01

    We discuss work towards understanding human left ventricle (LV) transport and mixing characteristics in normal subjects and patients with dilated cardiomyopathy. Prior studies have shown that the fluid dynamics in the left ventricle (LV) play a major role in dictating overall cardiac health. This study utilizes a noninvasive method to obtain planar velocity data over the apical long-axis view of the LV from color Doppler and B-mode ultrasound measurements. We use a Lagrangian measure to study unsteady behavior of blood transport inside the LV. We compute finite-time Lyapunov exponent (FTLE) fields to extract Lagrangian coherent structures (LCS) from the empirical data. This application presents a particular challenge to Lagrangian computations due to the presence of moving flux, and no-flux, boundaries. We describe a method for unstructured grid generation from the LV motion, and LCS computation on the deforming unstructured grid. Results demonstrate that LCS reveal the moving boundaries confining the blood volume injected to the LV in diastole and ejected into the aorta in systole. We discuss findings related to the quantification of the LV vortex, whose geometry and motion is thought to be an important indicator of cardiac health.

  8. Cross-sectional echocardiography. II. Analysis of mathematic models for quantifying volume of the formalin-fixed left ventricle.

    PubMed

    Wyatt, H L; Heng, M K; Meerbaum, S; Gueret, P; Hestenes, J; Dula, E; Corday, E

    1980-06-01

    Cross-sectional echocardiography was used to quantify volume in 21 canine left ventricles that were fixed in formalin and immersed in mineral oil. Area, length and diameter measurements were obtained from short- and long-axis cross-sectional images of the left ventricle and volume was calculated by seven mathematic models. Calculated volume was then compared, by linear regression and percent error analyses, with fluid volume of the left ventricle, obtained by filling the chamber with a known amount of fluid. Volumes ranged from 13-146 ml. Mathematic models using short-axis area and long-axis length gave higher correlation coefficients (r = 0.982 and r = 0.969) and lower mean errors (10-20%) than standard formulas previously used for M-mode echo and angiography. Thus, short-axis area analysis with cross-sectional echocardiography is well-suited for quantifying left ventricular volumes in dogs. PMID:7371124

  9. Finite element computational fluid mechanics

    NASA Technical Reports Server (NTRS)

    Baker, A. J.

    1983-01-01

    Finite element analysis as applied to the broad spectrum of computational fluid mechanics is analyzed. The finite element solution methodology is derived, developed, and applied directly to the differential equation systems governing classes of problems in fluid mechanics. The heat conduction equation is used to reveal the essence and elegance of finite element theory, including higher order accuracy and convergence. The algorithm is extended to the pervasive nonlinearity of the Navier-Stokes equations. A specific fluid mechanics problem class is analyzed with an even mix of theory and applications, including turbulence closure and the solution of turbulent flows.

  10. Cross-sectional echocardiography. I. Analysis of mathematic models for quantifying mass of the left ventricle in dogs.

    PubMed

    Wyatt, H L; Heng, M K; Meerbaum, S; Hestenes, J D; Cobo, J M; Davidson, R M; Corday, E

    1979-11-01

    Cross-sectional echocardiography was used to quantify left ventricular mass noninvasively in 21 dogs. Short- and long-axis cross-sectional images of the left ventricle were reproducibly traced at endocardial and epicardial borders during stop-motion video-tape replay. We used area, length and diameter measurements to calculate left ventricular mass by seven mathematic models, including the standard formulas used with M-mode echocardiography and cineangiography. Calculated mass was compared with excised weight of the left ventricle by regression and percent error analyses. Formulas using short-axis areas and long-axis length resulted in higher correlation coefficients (0.94--0.95) and lower mean errors (6--7%) than for standard formulas. Since short-axis areas account for regional left ventricular irregularities, noninvasive quantification of left ventricular mass by cross-sectional echocardiography in dogs is most accurate with formulas using short-axis areas. PMID:487544

  11. Measuring Regional Changes in the Diastolic Deformation of the Left Ventricle of SHR Rats Using microPET Technology and Hyperelastic Warping

    SciTech Connect

    Gullberg, Grant T; VERESS , ALEXANDER I.; WEISS, JEFFREY A.; HUESMAN, RONALD H.; REUTTER, BRYAN W.; TAYLOR , SCOTT E.; SITEK , AREK; FENG, BING; YANG , YONGFENG; GULLBERG, GRANT T.

    2008-04-04

    The objective of this research was to assess applicability of a technique known as hyperelastic warping for the measurement of local strains in the left ventricle (LV) directly from microPET image data sets. The technique uses differences in image intensities between template (reference) and target (loaded) image data sets to generate a body force that deforms a finite element (FE) representation of the template so that it registers with the target images. For validation, the template image was defined as the end-systolic microPET image data set from a Wistar Kyoto (WKY) rat. The target image was created by mapping the template image using the deformation results obtained from a FE model of diastolic filling. Regression analysis revealed highly significant correlations between the simulated forward FE solution and image derived warping predictions for fiber stretch (R2 = 0.96), circumferential strain (R2 = 0.96), radial strain (R2 = 0.93), and longitudinal strain (R2 = 0.76) (p<0.001for all cases). The technology was applied to microPET image data of two spontaneously hypertensive rats (SHR) and a WKY control. Regional analysis revealed that, the lateral freewall in the SHR subjects showed the greatest deformation compared with the other wall segments. This work indicates that warping can accurately predict the strain distributions during diastole from the analysis of microPET data sets.

  12. Toward automatic finite element analysis

    NASA Technical Reports Server (NTRS)

    Kela, Ajay; Perucchio, Renato; Voelcker, Herbert

    1987-01-01

    Two problems must be solved if the finite element method is to become a reliable and affordable blackbox engineering tool. Finite element meshes must be generated automatically from computer aided design databases and mesh analysis must be made self-adaptive. The experimental system described solves both problems in 2-D through spatial and analytical substructuring techniques that are now being extended into 3-D.

  13. Distance regularized two level sets for segmentation of left and right ventricles from cine-MRI.

    PubMed

    Liu, Yu; Captur, Gabriella; Moon, James C; Guo, Shuxu; Yang, Xiaoping; Zhang, Shaoxiang; Li, Chunming

    2016-06-01

    This paper presents a new level set method for segmentation of cardiac left and right ventricles. We extend the edge based distance regularized level set evolution (DRLSE) model in Li et al. (2010) to a two-level-set formulation, with the 0-level set and k-level set representing the endocardium and epicardium, respectively. The extraction of endocardium and epicardium is obtained as a result of the interactive curve evolution of the 0 and k level sets derived from the proposed variational level set formulation. The initialization of the level set function in the proposed two-level-set DRLSE model is generated from roughly located endocardium, which can be performed by applying the original DRLSE model. Experimental results have demonstrated the effectiveness of the proposed two-level-set DRLSE model. PMID:26740057

  14. The "bad" left ventricle. Results of coronary surgery and effect on late survival.

    PubMed

    Manley, J C; King, J F; Zeft, H J; Johnson, W D

    1976-12-01

    Between 1968 and 1971, 252 patients with severe ventricular malfunction underwent revascularization surgery. By means of single-plane ventriculography, the ventricle was divided into six segments, three anteriorly and three inferiorly, and ejection fractions were calculated. Patients were classified into four groups according to these observations. Results were assessed in regard to relief of angina, graft patency status, surgical mortality rate, and survival as determined by actuarial life-table analysis. These results were then compared to over-all medical and surgical experience contained in the Milwaukee Cardiovascular Data Registry as well as to other reported series of medical treatment for similar degrees of coronary artery disease and impairment of left ventricular function. Comparison between the surgical and medical series suggests improved survival and improved quality of life in the surgically treated patients. Thus many patients with severe ventricular malfunction, especially if associated with angina, can be reasonably considered candidates for surgery. PMID:994534

  15. Left ventricle motion modeling and analysis by adaptive-size physically based models

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Chen; Goldgof, Dmitry B.

    1992-06-01

    This paper presents a new physically based modeling method which employs adaptive-size meshes to model left ventricle (LV) shape and track its motion during cardiac cycle. The mesh size increases or decreases dynamically during surface reconstruction process to locate nodes near surface areas of interest and to minimize the fitting error. Further, presented with multiple 3-D data frames, the mesh size varies as the LV undergoes nonrigid motion. Simulation results illustrate the performance and accuracy of the proposed algorithm. Then, the algorithm is applied to the volumetric temporal cardiac data. The LV data was acquired by the 3-D computed tomography scanner. It was provided by Dr. Eric Hoffman at University of Pennsylvania Medical school and consists of 16 volumetric (128 by 128 by 118) images taken through the heart cycle.

  16. Pharmacological characterization of the activity of endogenous inotropic factor from porcine left ventricle.

    PubMed

    Chen, Q M; Chau, T; Agbanyo, M; Navaratnam, S; Khatter, J C; Bose, D

    1993-01-01

    We report some of the unique pharmacological properties of a semipurified endogenous inotropic factor (EIF) present in the extract of the porcine left ventricle. EIF produced the following effects: (a) increase in isometric contractile force developed by electrically driven canine right ventricular trabecula, reaching a maximum with 60-100 microliters/ml concentration; (b) inhibition of Na-pump activity in canine portal vein; (c) no digitalis-like cardiac toxicity, e.g., increased diastolic tension or spontaneous diastolic mechanical oscillatory activity, despite inhibition of the sodium pump; (d) a small increase in sarcoplasmic reticular Ca release from the heart but a large increase in transsarcolemmal Ca influx as seen in biphasic contractions, an action similar to that produced by digitalis-like substances; and (e) prolongation of the action potential duration and refractory period of the canine isolated trabeculae. This latter action may confer a unique antiarrhythmic property to EIF. PMID:7508042

  17. Automatic localization of the left ventricle in cardiac MRI images using deep learning.

    PubMed

    Emad, Omar; Yassine, Inas A; Fahmy, Ahmed S

    2015-08-01

    Automatic localization of the left ventricle (LV) in cardiac MRI images is an essential step for automatic segmentation, functional analysis, and content based retrieval of cardiac images. In this paper, we introduce a new approach based on deep Convolutional Neural Network (CNN) to localize the LV in cardiac MRI in short axis views. A six-layer CNN with different kernel sizes was employed for feature extraction, followed by Softmax fully connected layer for classification. The pyramids of scales analysis was introduced in order to take account of the different sizes of the heart. A publically-available database of 33 patients was used for learning and testing. The proposed method was able it localize the LV with 98.66%, 83.91% and 99.07% for accuracy, sensitivity and specificity respectively. PMID:26736354

  18. Left ventricular wall stress compendium.

    PubMed

    Zhong, L; Ghista, D N; Tan, R S

    2012-01-01

    Left ventricular (LV) wall stress has intrigued scientists and cardiologists since the time of Lame and Laplace in 1800s. The left ventricle is an intriguing organ structure, whose intrinsic design enables it to fill and contract. The development of wall stress is intriguing to cardiologists and biomedical engineers. The role of left ventricle wall stress in cardiac perfusion and pumping as well as in cardiac pathophysiology is a relatively unexplored phenomenon. But even for us to assess this role, we first need accurate determination of in vivo wall stress. However, at this point, 150 years after Lame estimated left ventricle wall stress using the elasticity theory, we are still in the exploratory stage of (i) developing left ventricle models that properly represent left ventricle anatomy and physiology and (ii) obtaining data on left ventricle dynamics. In this paper, we are responding to the need for a comprehensive survey of left ventricle wall stress models, their mechanics, stress computation and results. We have provided herein a compendium of major type of wall stress models: thin-wall models based on the Laplace law, thick-wall shell models, elasticity theory model, thick-wall large deformation models and finite element models. We have compared the mean stress values of these models as well as the variation of stress across the wall. All of the thin-wall and thick-wall shell models are based on idealised ellipsoidal and spherical geometries. However, the elasticity model's shape can vary through the cycle, to simulate the more ellipsoidal shape of the left ventricle in the systolic phase. The finite element models have more representative geometries, but are generally based on animal data, which limits their medical relevance. This paper can enable readers to obtain a comprehensive perspective of left ventricle wall stress models, of how to employ them to determine wall stresses, and be cognizant of the assumptions involved in the use of specific models

  19. Coupled Hemodynamic-Biochemical Modeling of Thrombus Formation in Infarcted Left Ventricles

    NASA Astrophysics Data System (ADS)

    Seo, Jung Hee; Vedula, Vijay; George, Richard; Mittal, Rajat

    2013-11-01

    Patients with heart failure (HF) and left ventricular (LV) systolic dysfunction have higher rates of thromboembolic events including embolic stroke and peripheral arterial thrombi. A common cause of arterial emboli in HF patients is myocardial infarction (MI) and subsequent left ventricular thrombus (LVT) formation. Stagnation of blood and endocardial injury are hypothesized to promote the development of LVT. The identification of high risk patients and the pharmacologic prevention of LVT formation are the keys to preventing embolic events. Stratification of patients at risk for LVT formation is currently limited, and primarily based on global assessment of ventricular function and image based assessment of ventricular wall motion. In this study, we explore a method to predict LVT risk using a multi-physics computational model. The blood flow in the left ventricle is simulated by solving the incompressible Navier-Stokes equation using an immersed boundary method and this is coupled to a convection-diffusion-reaction equation based model of platelet activation and coagulation. The results are then correlated with the other hemodynamic metrics such as wall shear stress and residence time to develop quantitative metrics for the LVT risk prediction. Supported by NSF CDI-Type II grant IOS-1124804, Computational resource by XSEDE NSF grant TG-CTS100002.

  20. Four-dimensional functional analysis of left and right ventricles using MR images and active appearance models

    NASA Astrophysics Data System (ADS)

    Zhang, Honghai; Thomas, Matthew T.; Walker, Nicholas E.; Stolpen, Alan H.; Wahle, Andreas; Scholz, Thomas D.; Sonka, Milan

    2007-03-01

    Conventional analysis of cardiac ventricular function from magnetic resonance images is typically relying on short axis image information only. Usually, two cardiac phases of the cardiac cycle are analyzed- the end-diastole and end-systole. Unfortunately, the short axis ventricular coverage is incomplete and inconsistent due to the lack of image information about the ventricular apex and base. In routine clinical images, this information is only available in long axis image planes. Additionally, the standard ventricular function indices such as ejection fraction are only based on a limited temporal information and therefore do not fully describe the four-dimensional (4D, 3D+time) nature of the heart's motion. We report a novel approach in which the long and short axis image data are fused to correct for respiratory motion and form a spatio-temporal 4D data sequence with cubic voxels. To automatically segment left and right cardiac ventricles, a 4D active appearance model was built. Applying the method to cardiac segmentation of tetralogy of Fallot (TOF) and normal hearts, our method achieved mostly subvoxel signed surface positioning errors of 0.2+/-1.1 voxels for normal left ventricle, 0.6+/-1.5 voxels for normal right ventricle, 0.5+/-2.1 voxels for TOF left ventricle, and 1.3+/-2.6 voxels for TOF right ventricle. Using the computer segmentation results, the cardiac shape and motion indices and volume-time curves were derived as novel indices describing the ventricular function in 4D.

  1. The NESSUS finite element code

    NASA Technical Reports Server (NTRS)

    Dias, J. B.; Nagiegaal, J. C.; Nakazawa, S.

    1987-01-01

    The objective of this development is to provide a new analysis tool which integrates the structural modeling versatility of a modern finite element code with the latest advances in the area of probabilistic modeling and structural reliability. Version 2.0 of the NESSUS finite element code was released last February, and is currently being exercised on a set of problems which are representative of typical Space Shuttle Main Engine (SSME) applications. NESSUS 2.0 allows linear elastostatic and eigenvalue analysis of structures with uncertain geometry, material properties and boundary conditions, which are subjected to a random mechanical and thermal loading environment. The NESSUS finite element code is a key component in a broader software system consisting of five major modules. NESSUS/EXPERT is an expert system under development at Southwest Research Institute, with the objective of centralizing all component-specific knowledge useful for conducting probabilistic analysis of typical Space Shuttle Main Engine (SSME) components. NESSUS/FEM contains the finite element code used for the structural analysis and parameter sensitivity evaluation of these components. The task of parametrizing a finite element mesh in terms of the random variables present is facilitated with the use of the probabilistic data preprocessor in NESSUS/PRE. An external database file is used for managing the bulk of the data generated by NESSUS/FEM.

  2. Postnatal growth of cardiomyocytes in the left ventricle of the rat.

    PubMed

    Wulfsohn, D; Nyengaard, J R; Tang, Y

    2004-03-01

    We studied the development of myocytes and interstitium using perfusion-fixed left ventricles obtained from normal female Wistar rats at 5 days (n = 5), 25 days (n = 5), and 125 days (n = 5) of age. Using design-based stereological methods and light microscopy, we estimated the following parameters: volume of left ventricle made up by myocytes, myocyte nuclei, and interstitium; total numbers of myocyte and non-myocyte nuclei; mean volumes of myocyte nuclei; the total volume, surface area, and length of fibers; and the mean star volumes of fibers. Some derived parameters were also calculated, namely, the mean myocardium volume per nucleus and the mean fiber cross-sectional area. We found that postnatal myocyte growth after day 5 in the young rat is largely hypertrophic, while interstitial growth is hyperplastic. The increase in left ventricular mass was 10-fold over the ages studied, whereas total length, surface area, and volume of fibers increased approximately 3-, 8-, and 11-fold over the period. Relative rates of growth implied that fiber growth was dominated by an increase in length compared to other dimensions. The total number of myocyte nuclei ( approximately 30 x 10(6)) did not change between 5 and 25 days of age, but then almost doubled in 125-day-old rats. The number of non-myocyte nuclei increased 9-fold over the period studied in an exponential manner. The mean myocyte nucleus volume tripled between the ages of 5 and 25 days and then remained the same. The volume-weighted mean nucleus volume was highly variable and showed no significant trend with age. Our results provide support for the claim made by some researchers that myocyte proliferation had ceased by day 5 after birth, but do not provide evidence for binucleation of myocytes between 5 and 25 days after birth. Reported numbers of myocyte nuclei express a net growth and do not rule out both myocyte death and creation throughout the early postnatal period. We clearly detect an increase in the

  3. Cancer induces cardiomyocyte remodeling and hypoinnervation in the left ventricle of the mouse heart.

    PubMed

    Mühlfeld, Christian; Das, Suman Kumar; Heinzel, Frank R; Schmidt, Albrecht; Post, Heiner; Schauer, Silvia; Papadakis, Tamara; Kummer, Wolfgang; Hoefler, Gerald

    2011-01-01

    Cancer is often associated with cachexia, cardiovascular symptoms and autonomic dysregulation. We tested whether extracardiac cancer directly affects the innervation of left ventricular myocardium. Mice injected with Lewis lung carcinoma cells (tumor group, TG) or PBS (control group, CG) were analyzed after 21 days. Cardiac function (echocardiography), serum levels of TNF-α and Il-6 (ELISA), structural alterations of cardiomyocytes and their innervation (design-based stereology) and levels of innervation-related mRNA (quantitative RT-PCR) were analysed. The groups did not differ in various functional parameters. Serum levels of TNF-α and Il-6 were elevated in TG. The total length of axons in the left ventricle was reduced. The number of dense core vesicles per axon profile was reduced. Decreased myofibrillar volume, increased sarcoplasmic volume and increased volume of lipid droplets were indicative of metabolic alterations of TG cardiomyocytes. In the heart, the mRNA level of nerve growth factor was reduced whereas that of β1-adrenergic receptor was unchanged in TG. In the stellate ganglion of TG, mRNA levels of nerve growth factor and neuropeptide Y were decreased and that of tyrosine hydroxylase was increased. In summary, cancer induces a systemic pro-inflammatory state, a significant reduction in myocardial innervation and a catabolic phenotype of cardiomyocytes in the mouse. Reduced expression of nerve growth factor may account for the reduced myocardial innervation. PMID:21637823

  4. [Electrovectorcardiographic aspects of systolic and diastolic overloads of the left ventricle].

    PubMed

    de Micheli, A; Medrano, G A; Casanova, J M

    1990-01-01

    Electrovectorcardiographic features of the ventricular depolarization and repolarization related to hemodynamic conditions were studied in typical cases of left ventricular systolic and diastolic overloads. Electrovectorcardiographic exploration was effected prospectively in 70 subjects with aortic coarctation (52 men and 18 women) and in 90 with patent ductus arteriosus (18 men and 72 women). Fifty-five subjects of the series with systolic overload (A) and sixty-five with diastolic overload (B) underwent surgical treatment. In all cases, high fidelity tracings were obtained by means of a VR-6 polygraph: standard leads, unipolar limb leads, thoracic and precordial unipolar leads from V7R to V7 or V8, high abdominal leads MD, ME, MI and, when it was possible, the corresponding intraventricular unipolar leads. Vectorcardiographic curves were recorded in three planes by Grishman's cube method and photographed using the polaroid system. In both series, ventricular conduction disturbances of proximal or peripheral types were observed. These seem to be independent of hemodynamic conditions. In the presence of aortic coarctation as well as of patent ductus arteriosus, the Q-Tc interval can be prolonged in all leads, probably owing to electrolytic disorders, or in left leads only as a reflection of elevated telediastolic pressure in the ipsilateral ventricle. PMID:2378532

  5. Case Report: Disparate flow in HeartMate II patient with extensive left ventricle repair.

    PubMed

    Tran, Phat L; Kazui, Toshinobu; Perovic, Viktor; Mikail, Philmon; Lick, Scott; Smith, Richard; Betterton, Edward W; Venkat, Raj; Iwanski, Jessika; Wong, Raymond K; Slepian, Marvin J; Khalpey, Zain

    2016-05-01

    This case study reports the operative management of a 63-year-old male patient following implantation of the HeartMate II (HMII) left ventricular assist device (LVAD), with a non-compliant left ventricle (LV) and a reduced right ventricular (RV) end-diastolic volume. Intraoperatively, the patient had a thin, fragile LV wall with laminated clot; a ventricular septal defect was encountered during removal of the clot. Along with an aortic valve repair, the LV and the septum were reconstructed with multiple bovine pericardium patches, thus, moderately reducing the RV and LV stroke volume. A difference in cardiac output via a Swan-Ganz catheter (approximately 1.5 l/min) was observed as opposed to the HMII's estimated flow. The result was later replicated and verified ITALIC! in vitrovia the Donovan Mock Circulation System (DMCS), where about 2 l/min lower flow on the HMII system was observed. In conclusion, the HMII flow rate displayed can be inaccurate and should only be used for trending. PMID:26531760

  6. The Effects of Training on the Time Components of the Left Ventricle, and Cardiac Time Components: Sedentary versus Active Individuals.

    ERIC Educational Resources Information Center

    Plowman, Sharon Ann

    A review of previous research was completed to determine (a) the response of the cardiac time components of the left ventricle to varying types and intensities of training programs, (b) the probable physiological explanations for these responses, and (c) the significance of the changes which did or did not occur. It was found that, at rest,…

  7. Probabilistic Finite Element: Variational Theory

    NASA Technical Reports Server (NTRS)

    Belytschko, T.; Liu, W. K.

    1985-01-01

    The goal of this research is to provide techniques which are cost-effective and enable the engineer to evaluate the effect of uncertainties in complex finite element models. Embedding the probabilistic aspects in a variational formulation is a natural approach. In addition, a variational approach to probabilistic finite elements enables it to be incorporated within standard finite element methodologies. Therefore, once the procedures are developed, they can easily be adapted to existing general purpose programs. Furthermore, the variational basis for these methods enables them to be adapted to a wide variety of structural elements and to provide a consistent basis for incorporating probabilistic features in many aspects of the structural problem. Tasks concluded include the theoretical development of probabilistic variational equations for structural dynamics, the development of efficient numerical algorithms for probabilistic sensitivity displacement and stress analysis, and integration of methodologies into a pilot computer code.

  8. Finite elements: Theory and application

    NASA Technical Reports Server (NTRS)

    Dwoyer, D. L. (Editor); Hussaini, M. Y. (Editor); Voigt, R. G. (Editor)

    1988-01-01

    Recent advances in FEM techniques and applications are discussed in reviews and reports presented at the ICASE/LaRC workshop held in Hampton, VA in July 1986. Topics addressed include FEM approaches for partial differential equations, mixed FEMs, singular FEMs, FEMs for hyperbolic systems, iterative methods for elliptic finite-element equations on general meshes, mathematical aspects of FEMS for incompressible viscous flows, and gradient weighted moving finite elements in two dimensions. Consideration is given to adaptive flux-corrected FEM transport techniques for CFD, mixed and singular finite elements and the field BEM, p and h-p versions of the FEM, transient analysis methods in computational dynamics, and FEMs for integrated flow/thermal/structural analysis.

  9. Second order tensor finite element

    NASA Technical Reports Server (NTRS)

    Oden, J. Tinsley; Fly, J.; Berry, C.; Tworzydlo, W.; Vadaketh, S.; Bass, J.

    1990-01-01

    The results of a research and software development effort are presented for the finite element modeling of the static and dynamic behavior of anisotropic materials, with emphasis on single crystal alloys. Various versions of two dimensional and three dimensional hybrid finite elements were implemented and compared with displacement-based elements. Both static and dynamic cases are considered. The hybrid elements developed in the project were incorporated into the SPAR finite element code. In an extension of the first phase of the project, optimization of experimental tests for anisotropic materials was addressed. In particular, the problem of calculating material properties from tensile tests and of calculating stresses from strain measurements were considered. For both cases, numerical procedures and software for the optimization of strain gauge and material axes orientation were developed.

  10. Element-topology-independent preconditioners for parallel finite element computations

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Alexander, Scott

    1992-01-01

    A family of preconditioners for the solution of finite element equations are presented, which are element-topology independent and thus can be applicable to element order-free parallel computations. A key feature of the present preconditioners is the repeated use of element connectivity matrices and their left and right inverses. The properties and performance of the present preconditioners are demonstrated via beam and two-dimensional finite element matrices for implicit time integration computations.

  11. Failing Left Ventricles Have an Enhanced Post-Stimulation Potentiation Despite Their Impaired Force Frequency Relationship.

    PubMed

    Watanabe, Tohru; Kashimura, Takeshi; Kodama, Makoto; Tanaka, Komei; Fujiki, Shinya; Hayashi, Yuka; Obata, Hiroaki; Hanawa, Haruo; Minamino, Tohru

    2016-05-25

    The left ventricular contractile force (LV dP/dtmax) of patients with left ventricular systolic dysfunction does not increase effectively with an increase in heart rate. In other words, their force-frequency relationship (FFR) is impaired. However, it is unknown whether a longer coupling interval subsequent to tachycardia causes a stronger contraction (poststimulation potentiation, PSP) in a rate-dependent manner.In 16 patients with idiopathic dilated cardiomyopathy (DCM) (48 ± 2 years old, LVEF 30 ± 10%) and 6 control patients (58 ± 4 years old, LVEF 70 ± 7%), FFR was assessed by right atrial pacing using a micro-manometer-tipped catheter. At each pacing rate, the increase of LV dP/dtmax over basal LV dP/dt (ΔFFR) and the increase of LV dP/dtmax of the first beat after pacing cessation over LV dP/dtmax during pacing (ΔPSP) were evaluated.Patients with DCM had smaller LV dP/dtmax at baseline (872 ± 251 versus 1370 ± 123 mmHg/second, P = 0.0002) and developed smaller ΔFFR (eg, at 120/minute, 77 ± 143 versus 331 ± 131 mmHg/second, P = 0.0011). In contrast, they showed a rate-dependent increase of LV dP/dtmax of PSP and had greater ΔPSP (eg, at 120/minute, 294 ± 173 versus -152 ± 131 mmHg/second, P < 0.0001).Failing left ventricles develop little contractile force during tachycardia despite their rate-dependent enhancement in post-stimulation potentiation, suggesting that refractoriness of contractile force underlies impaired FFR. PMID:27181036

  12. Simulated Microgravity and Recovery-Induced Remodeling of the Left and Right Ventricle

    PubMed Central

    Zhong, Guohui; Li, Yuheng; Li, Hongxing; Sun, Weijia; Cao, Dengchao; Li, Jianwei; Zhao, Dingsheng; Song, Jinping; Jin, Xiaoyan; Song, Hailin; Yuan, Xinxin; Wu, Xiaorui; Li, Qi; Xu, Qing; Kan, Guanghan; Cao, Hongqing; Ling, Shukuan; Li, Yingxian

    2016-01-01

    Physiological adaptations to microgravity involve alterations in cardiovascular systems. These adaptations result in cardiac remodeling and orthostatic hypotension. However, the response of the left ventricle (LV) and right ventricle (RV) following hindlimb unloading (HU) and hindlimb reloading (HR) is not clear and the underlying mechanism remains to be understood. In this study, three groups of mice were subjected to HU by tail suspension for 28 days. Following this, two groups were allowed to recover for 7 or 14 days. The control group was treated equally, with the exception of tail suspension. Echocardiography was performed to detect the structure and function changes of heart. Compared with the control, the HU group of mice showed reduced LV-EF (ejection fraction), and LV-FS (fractional shortening). However, mice that were allowed to recover for 7 days after HU (HR-7d) showed increased LVIDs (systolic LV internal diameter) and LV Vols (systolic LV volume). Mice that recovered for 14 days (HR-14d) returned to the normal state. In comparison, RV-EF and RV-FS didn't recover to the normal conditions till being reloaded for 14 days. Compared with the control, RVIDd (diastolic RV internal diameter), and RV Vold (diastolic RV volume) were reduced in HU group and recovered to the normal conditions in HR-7d and HR-14d groups, in which groups RVIDs (systolic RV internal diameter) and RV Vols (systolic RV volume) were increased. Histological analysis and cardiac remodeling gene expression results indicated that HU induces left and right ventricular remodeling. Western blot demonstrated that the phosphorylation of HDAC4 and ERK1/2 and the ratio of LC3-II / LC3-I, were increased following HU and recovered following HR in both LV and RV, and the phosphorylation of AMPK was inhibited in both LV and RV following HU, but only restored in LV following HR for 14 days. These results indicate that simulated microgravity leads to cardiac remodeling, and the remodeling changes can

  13. A Three-Dimensional Analytical (Rheological) Model of the Human Left Ventricle in Passive-Active States

    PubMed Central

    Ghista, Dhanjoo N.; Brady, Allan J.; Radhakrishnan, S.

    1973-01-01

    In this paper a three-dimensional continuum model of a mammalian left ventricle is formulated. The stresses in the model satisfy the conditions of zero stress on the outer (epicardial surface-representing) boundary. The strains of the model are obtained from the actual dynamic geometry measurements (obtained from cineangiocardiography). Since the left ventricular muscle is incompressible, the dilatational strain is zero and hence the (three-dimensional) deviatric stress components are related to the corresponding strain components by Maxwell and Voigt rheological model analogues of one-dimensional systems; the parameters of the model are series and parallel elastic (SE, PE) elements and the contractile element (CE) (representing the sarcomere). The incorporation of the rheological features of the cardiac muscle into the three-dimensional constitutive equations (for the three-dimensional continuum model of the left ventricle) is a feature of this paper. A procedure is presented to determine the parameters of the constitutive equations (i.e., the SE, PE, and the parameters of the force-velocity relation for the CE) for the left ventricle of a subject from data on the dimensions and chamber pressure of the left ventricle. The values of these parameters characterize the rheology of the left ventricular muscle of the subject. In order to demonstrate clinical application of the analyses, in vivo data of the subjects' left ventricular pressure and dimensions are obtained, and the analyses are applied to the data to determine (for each subject) the values and characteristics of the elastic elements and CEs. PMID:4726883

  14. [Mathematical Modelling of the Dependence of the Performance of the Left Ventricle of the Heart on Preload and Afterload].

    PubMed

    Syomin, F A; Zberia, M V; Koubassova, N A; Tsaturyan, A K

    2015-01-01

    The results of the numerical simulation of the end-diastolic, end-systolic and stroke volumes of the left ventricle of the heart are presented. The simulation was based on a published simple kinetic model of cardiac muscle and approximation of the ventricle geometry with thick-wall cylinder where the fibre orientation varied linearly from sub-epicardium towards sub-endocardium. Blood flow was modelled with a liner compartment model. This simplified approach provides correct dependencies of the stroke volume on the pre- and afterload, namely end-diastolic pressure and peripheral resistance. The calculations show that the stroke volume is independent of arterial compliance and blood inertia. PMID:26841514

  15. Constrictive pericarditis with a calcified pericardial band at the level of left ventricle causing mid-ventricular obstruction.

    PubMed

    Gautam, Mani Prasad; Gautam, Samir; Sogunuru, Guruprasad; Subramanyam, Gangapatnam

    2012-01-01

    An adolescent presented with insidious onset and gradually progressive distension of abdomen associated with bilateral ankle swelling of few months duration. He had one episode of prolonged low-grade self-limiting febrile illness during childhood but had not consulted to doctor and never had been diagnosed as case of tuberculosis or acute pericarditis. A detail clinical evaluation showed raised central venous pressure, ascites and ankle oedema. Systemic examination was not much informative except ejection systolic murmur in third left intercostal space. Echocardiography and CT scan heart showed localised thickened pericardium with calcific band around the left ventricle at mid ventricle level. The band around the heart caused the heart to have a 'dumbbell' appearance with ballooning in apical area and a rare mid-ventricular obstruction in the left. A diagnosis of chronic constrictive pericarditis with calcific band was made and the patient was referred to another centre for cardiac surgery. PMID:22605003

  16. In-vivo characterization of left-ventricle pressure-volume telemetry system in swine model.

    PubMed

    Fricke, Kyle; Konecny, Filip; El-Warrak, Alexander; Hodgson, Chad; Cadieux-Pitre, Heather; Hill, Tracy; Sobot, Robert

    2016-10-01

    We present in-vivo study related to the use of our implantable RF telemetry system for pressure-volume (PV) cardiac monitoring in a animal subject. We implant a commercial MEMS PV sensor into the subject's heart left-ventricle (LV), while the telemetry system is implanted outside of the heart and connected to the sensor with a 7-microwires tether. The RF telemetry system is suitable for commercial application in medium sized subjects, its total volume of 2.475cm(3) and a weight of 4.0g. Our designed system is 58 % smaller in volume, 44 % in weight and has a 55 % reduction in sampling power over the last reported research in PV telemetry. In-vivo data was captured in both an acute and a freely moving setting over a 24 hour period. We experimentally demonstrated viability of the methodology that includes the surgical procedure and real-time monitoring of the in-vivo data in a freely moving subject. Further improvements in catheter design will improve the data quality and safety of the subject. This real-time implantable technology allows for researchers to quantify cardiac pathologies by extracting real-time pressure-volume loops, wirelessly from within freely moving subjects. PMID:27492638

  17. Chloroquine improves left ventricle diastolic function in streptozotocin-induced diabetic mice.

    PubMed

    Yuan, Xun; Xiao, Yi-Chuan; Zhang, Gui-Ping; Hou, Ning; Wu, Xiao-Qian; Chen, Wen-Liang; Luo, Jian-Dong; Zhang, Gen-Shui

    2016-01-01

    Diabetes is a potent risk factor for heart failure with preserved ejection fraction (HFpEF). Autophagy can be activated under pathological conditions, including diabetic cardiomyopathy. The therapeutic effects of chloroquine (CQ), an autophagy inhibitor, on left ventricle function in streptozotocin (STZ)-induced diabetic mice were investigated. The cardiac function, light chain 3 (LC3)-II/LC3-I ratio, p62, beclin 1, reactive oxygen species, apoptosis, and fibrosis were measured 14 days after CQ (ip 60 mg/kg/d) administration. In STZ-induced mice, cardiac diastolic function was decreased significantly with normal ejection fraction. CQ significantly ameliorated cardiac diastolic function in diabetic mice with HFpEF. In addition, CQ decreased the autophagolysosomes, cardiomyocyte apoptosis, and cardiac fibrosis but increased LC3-II and p62 expressions. These results suggested that CQ improved the cardiac diastolic function by inhibiting autophagy in STZ-induced HFpEF mice. Autophagic inhibitor CQ might be a potential therapeutic agent for HFpEF. PMID:27621594

  18. [HEMODYNAMIC CHILDREN WITH ISOLATED ANOMALOUS CHORDS OF THE LEFT VENTRICLE DEPENDING ON LOCATION AND QUANTITY].

    PubMed

    Kondrashova, V G

    2015-01-01

    A total of 156 children group (children born to parents exposed to the Chernobyl disaster), in which, according to Doppler echocardiography, revealed isolated abnormal chords of the left ventricle (AHLV). Analysis of morphometric parameters and central hemodynamics conducted according to the localization AHLV. Found that concomitant localization AHLV at the threshold of the number of the most influencing change morphoinetric indicators and central hemodynamics. Condition of systemic circulation indicates a decline in their adaptive capacity of the cardiovascular system due to changes in the dynamics and power of the heartbeat. The decrease in stroke volume, stroke and cardiac index suggests hypokinetic type of organization of central hemodynamics, which can be considered an early sign of stress features of the heart and blood vessels. In this subgroup of children revealed significant changes in transmitral flow, indicating the initiation they have diastolic dysfunc tion. When the number of prethreshold AHLV most pronounced changes were found in the middle of their localization. Almost a third of children in this subgroup with individual assessment also revealed signs of initiation of diastolic dysfunction. PMID:27089709

  19. Assessment of left ventricle systolic and diastolic functions in schizophrenia patients.

    PubMed

    Korkmaz, Sevda; Korkmaz, Hasan; Özer, Ömer; Atmaca, Murad

    2016-06-30

    The objective of the study was to scrutinize in detail the changes that occur in left ventricle (LV) systolic and diastolic functions using echocardiography in patients with at least 5 years of history and 40 healthy volunteers matching the patients in age and gender, who were enrolled in a cross-sectional study. All cases were examined with Tei Index, an index that could assess LV systolic and diastolic functions in conjuction, and with LV ejection fraction (LVEF) that assesses systolic function. In addition, Mitral E and A wave velocities, Isovolemic relaxation time (IVRT), Tissue Doppler Em (peak early motion) and Am (peak after motion) waves, which evaluate diastolic functions were measured. Tei Index was calculated as 0.61±0.19 in the patient group, and as 0.39±0.10 in the control group and the difference was statistically significant (p<0.001). LVEF was measured as 58%±5 in the patient group, and as 62%±3 in the control group and the difference was statistically significant (p<0.001). Also the IVRT values were significantly different between the tissue Doppler Em and Em/Am ratio among the groups (p<0.001). Echocardiographic myocardial performance, LV systolic and diastolic functions in schizophrenia patients was found to be worse than those of the control group. PMID:27138830

  20. Cardiac Cell Culture Model (CCCM) as a Left Ventricle Mimic for Cardiac Tissue Generation

    PubMed Central

    Nguyen, Mai-Dung; Tinney, Joseph P.; Yuan, Fangping; Roussel, Thomas J.; El-Baz, Ayman; Giridharan, Guruprasad; Keller, Bradley B.; Sethu, Palaniappan

    2013-01-01

    A major challenge in cardiac tissue engineering is the delivery of hemodynamic mechanical cues that play a critical role in the early development and maturation of cardiomyocytes. Generation of functional cardiac tissue capable of replacing or augmenting cardiac function therefore requires physiologically relevant environments that can deliver complex mechanical cues for cardiomyocyte functional maturation. The goal of this work is the development and validation of a cardiac cell culture model (CCCM) microenvironment that accurately mimics pressure-volume changes seen in the left ventricle and to use this system to achieve cardiac cell maturation under conditions where mechanical loads such as pressure and stretch are gradually increased from the unloaded state to conditions seen in vivo. The CCCM platform, consisting of a cell culture chamber integrated within a flow loop was created to accomplish culture of 10 day chick embryonic ventricular cardiomyocytes subject to 4 days of stimulation (10 mm Hg, ~13% stretch at a frequency of 2 Hz). Results clearly show that CCCM conditioned cardiomyocytes accelerate cardiomyocyte structural and functional maturation in comparison to static unloaded controls as evidenced by increased proliferation, alignment of actin cytoskeleton, bundle-like sarcomeric α-actinin expression, higher pacing beat rate at lower threshold voltages and increased shortening. These results confirm the CCCM microenvironment can accelerate immature cardiac cell structural and functional maturation for potential cardiac regenerative applications. PMID:23952579

  1. Flow Behavior in the Left Heart Ventricle Following Apico-Aortic Bypass Surgery

    NASA Astrophysics Data System (ADS)

    Shahriari, Shahrokh; Jeyhani, Morteza; Labrosse, Michel; Kadem, Lyes

    2013-11-01

    Apico-aortic bypass (AAB) surgery is an alternative for transcatheter aortic valve implantation (TAVI) to reduce left ventricle (LV) overload in patients with severe aortic stenosis (AS). It consists in connecting the apex of the LV to the descending thoracic aorta with a valved conduit. Postoperative flow assessments show that two thirds of the outflow is conducted from the LV apex to the conduit, while only one third crosses the native aortic valve. In this study, we performed high speed particle image velocimetry (PIV) measurements of flow pattern within an in vitro elastic model of LV in the presence of a very severe AS, before and after AAB. Results indicate that AAB effectively relieves the LV outflow obstruction; however, it also leads to abnormal ventricular flow patterns. Normal LV flow dynamics is characterized by an emerging mitral jet flow followed by the development of a vortical flow with velocities directed towards the aortic valve, while measurements in the presence of AAB show systolic flow bifurcating to the apical conduit and to the aortic valve outflow tract. This study provides the first insight into the LV flow structure after AAB including outflow jets and disturbed stagnation regions.

  2. Manifold parametrization of the left ventricle for a statistical modelling of its complete anatomy

    NASA Astrophysics Data System (ADS)

    Gil, D.; Garcia-Barnes, J.; Hernández-Sabate, A.; Marti, E.

    2010-03-01

    Distortion of Left Ventricle (LV) external anatomy is related to some dysfunctions, such as hypertrophy. The architecture of myocardial fibers determines LV electromechanical activation patterns as well as mechanics. Thus, their joined modelling would allow the design of specific interventions (such as peacemaker implantation and LV remodelling) and therapies (such as resynchronization). On one hand, accurate modelling of external anatomy requires either a dense sampling or a continuous infinite dimensional approach, which requires non-Euclidean statistics. On the other hand, computation of fiber models requires statistics on Riemannian spaces. Most approaches compute separate statistical models for external anatomy and fibers architecture. In this work we propose a general mathematical framework based on differential geometry concepts for computing a statistical model including, both, external and fiber anatomy. Our framework provides a continuous approach to external anatomy supporting standard statistics. We also provide a straightforward formula for the computation of the Riemannian fiber statistics. We have applied our methodology to the computation of complete anatomical atlas of canine hearts from diffusion tensor studies. The orientation of fibers over the average external geometry agrees with the segmental description of orientations reported in the literature.

  3. Automatic Endocardium Contour Tracing Method Using Standard Left Ventricles Shape Model

    NASA Astrophysics Data System (ADS)

    Horie, Masahiro; Kashima, Masayuki; Sato, Kiminori; Watanabe, Mutsumi

    The necessity of ultrasonic diagnosis tools increases every year. We propose an automatic endocardium tracing method by applying prepared “Standard Left Ventricles Shape Model (SLVSM)”. The cross section of heart wall in ultrasonic image is decided depending on the position and the angle of this probe. The initial contour is adaptively determined as crossing curve line between the SLVSM and the cross section. And the endocardium contour is extracted by active contour model(ACM) in two stages. In the first stage, an endocardium contour is detected using the result of an edge extraction based on the separability of image features. In the second stage, the endocardium contour is extracted using shape correction processing. “Mitral valve processing” not only detects the position of the mitral valve at the end diastolic period, but also corrects the detected contour after the first stage of ACM. Experimental results using one healthy case and three diseased cases have shown the effectiveness of the proposed method.

  4. Accurate segmentation framework for the left ventricle wall from cardiac cine MRI

    NASA Astrophysics Data System (ADS)

    Sliman, H.; Khalifa, F.; Elnakib, A.; Soliman, A.; Beache, G. M.; Gimel'farb, G.; Emam, A.; Elmaghraby, A.; El-Baz, A.

    2013-10-01

    We propose a novel, fast, robust, bi-directional coupled parametric deformable model to segment the left ventricle (LV) wall borders using first- and second-order visual appearance features. These features are embedded in a new stochastic external force that preserves the topology of LV wall to track the evolution of the parametric deformable models control points. To accurately estimate the marginal density of each deformable model control point, the empirical marginal grey level distributions (first-order appearance) inside and outside the boundary of the deformable model are modeled with adaptive linear combinations of discrete Gaussians (LCDG). The second order visual appearance of the LV wall is accurately modeled with a new rotationally invariant second-order Markov-Gibbs random field (MGRF). We tested the proposed segmentation approach on 15 data sets in 6 infarction patients using the Dice similarity coefficient (DSC) and the average distance (AD) between the ground truth and automated segmentation contours. Our approach achieves a mean DSC value of 0.926±0.022 and AD value of 2.16±0.60 compared to two other level set methods that achieve 0.904±0.033 and 0.885±0.02 for DSC; and 2.86±1.35 and 5.72±4.70 for AD, respectively.

  5. ATP synthesis and export in heart left ventricle mitochondria from spontaneously hypertensive rat.

    PubMed

    Atlante, A; Seccia, T M; Pierro, P; Vulpis, V; Marra, E; Pirrelli, A; Passarella, S

    1998-04-01

    Use was made of mitochondria isolated from heart left ventricles of either spontaneously hypertensive or age-matched Wistar-Kyoto rats used as a control to find out whether hypertrophy (5-week-old rats) or hypertrophy/hypertension (24-week-old rats) can cause change in the mechanisms by which ATP is synthesised via ATP synthase and subsequently exported via the ADP/ATP translocator outside mitochondria. To do this, photometric measurements were made of the rate of ATP appearance in the extramitochondrial phase, which occurs as a result of ADP addition to mitochondria. In mitochondria from spontaneously hypertensive rats deficit of ATP production was found dependent on changes in the KmADP and Vmax values of both the ADP/ATP translocator and the ATP synthase. The ADP/ATP translocator was found to determine the rate of ATP production outside mitochondria in all the tested samples. In an initial investigation carried out to ascertain how cell ATP deficit can be counterbalanced, an increase in both adenylate kinase and creatine kinase activities was found in both hypertrophy and hypertrophy/hypertension. A possible increase in anaerobic glycolysis was also suggested by the increased lactate dehydrogenase activity. PMID:9852286

  6. Accelerated circumferential strain quantification of the left ventricle using CIRCOME: simulation and factor analysis

    NASA Astrophysics Data System (ADS)

    Moghaddam, Abbas N.; Finn, J. Paul

    2008-03-01

    Circumferential strain of the left ventricle reflects myocardial contractility and is considered a key index of cardiac function. It is also an important parameter in the quantitative evaluation of heart failure. Circumferential compression encoding, CIRCOME, is a novel method in cardiac MRI to evaluate this strain non-invasively and quickly. This strain encoding technique avoids the explicit measurement of the displacement field and does not require calculation of strain through spatial differentiation. CIRCOME bypasses these two time-consuming and noise sensitive steps by directly using the frequency domain (k-space) information from radially tagged myocardium, before and after deformation. It uses the ring-shaped crown region of the k-space, generated by the taglines, to reconstruct circumferentially compression-weighted images of the heart before and after deformation. CIRCOME then calculates the circumferential strain through relative changes in the compression level of corresponding regions before and after deformation. This technique can be implemented in 3D as well as 2D and may be employed to estimate the overall global or regional circumferential strain. The main parameters that affect the accuracy of this method are spatial resolution, signal to noise ratio, eccentricity of the center of radial taglines their fading and their density. Also, a variety of possible image reconstruction and filtering options may influence the accuracy of the method. This study describes the pulse sequence, algorithm, influencing factors and limiting criteria for CIRCOME and provides the simulated results.

  7. Chloroquine improves left ventricle diastolic function in streptozotocin-induced diabetic mice

    PubMed Central

    Yuan, Xun; Xiao, Yi-Chuan; Zhang, Gui-Ping; Hou, Ning; Wu, Xiao-Qian; Chen, Wen-Liang; Luo, Jian-Dong; Zhang, Gen-Shui

    2016-01-01

    Diabetes is a potent risk factor for heart failure with preserved ejection fraction (HFpEF). Autophagy can be activated under pathological conditions, including diabetic cardiomyopathy. The therapeutic effects of chloroquine (CQ), an autophagy inhibitor, on left ventricle function in streptozotocin (STZ)-induced diabetic mice were investigated. The cardiac function, light chain 3 (LC3)-II/LC3-I ratio, p62, beclin 1, reactive oxygen species, apoptosis, and fibrosis were measured 14 days after CQ (ip 60 mg/kg/d) administration. In STZ-induced mice, cardiac diastolic function was decreased significantly with normal ejection fraction. CQ significantly ameliorated cardiac diastolic function in diabetic mice with HFpEF. In addition, CQ decreased the autophagolysosomes, cardiomyocyte apoptosis, and cardiac fibrosis but increased LC3-II and p62 expressions. These results suggested that CQ improved the cardiac diastolic function by inhibiting autophagy in STZ-induced HFpEF mice. Autophagic inhibitor CQ might be a potential therapeutic agent for HFpEF. PMID:27621594

  8. Radiofrequency catheter ablation of the atrioventricular junction from the left ventricle

    SciTech Connect

    Sousa, J.; el-Atassi, R.; Rosenheck, S.; Calkins, H.; Langberg, J.; Morady, F. )

    1991-08-01

    The purpose of this study was to describe a new technique for catheter ablation of the atrioventricular junction using radiofrequency energy delivered in the left ventricle. Catheter ablation of the atrioventricular (AV) junction using a catheter positioned across the tricuspid annulus was unsuccessful in eight patients with a mean {plus minus} SD age of 51 {plus minus} 19 years who had AV nodal reentry tachycardia (three patients), orthodromic tachycardia using a concealed midseptal accessory pathway, atrial tachycardia, atrial flutter (two patients), or atrial fibrillation. Before attempts at catheter ablation of the AV junction, each patient had been refractory to pharmacological therapy, and four had failed attempts at either catheter modification of the AV node using radiofrequency energy or surgical and catheter ablation of the accessory pathway. Conventional right-sided catheter ablation of the AV junction using radiofrequency energy in six patients and both radiofrequency energy and direct current shocks in two patients was ineffective. The mean amplitude of the His bundle potential recorded at the tricuspid annulus at the sites of unsuccessful AV junction ablation was 0.1 {plus minus} 0.08 mV, with a maximum His amplitude of 0.03-0.28 mV. A 7F deflectable-tip quadripolar electrode catheter with a 4-mm distal electrode was positioned against the upper left ventricular septum using a retrograde aortic approach from the femoral artery. Third-degree AV block was induced in each of the eight patients with 20-36 W applied for 15-30 seconds. The His bundle potential at the sites of successful AV junction ablation ranged from 0.06 to 0.99 mV, with a mean of 0.27 {plus minus} 0.32 mV. There was no rise in the creatine kinase-MB fraction and no complications occurred. An intrinsic escape rhythm of 30-60 beats/min was present in seven of the eight patients.

  9. Echocardiographic detection of free-floating thrombus in left ventricle during coronary artery bypass grafting

    PubMed Central

    Vaggar, Jagadeesh N.; Gadhinglajkar, Shrinivas; Pillai, Vivek; Sreedhar, Rupa; Cahndran, Roshith; Roy, Suddhadeb

    2015-01-01

    We report an incident of detection of a free-floating thrombus in the left ventricle (LV) using intraoperative two-dimensional (2D) and three-dimensional (3D) transesophageal echocardiography (TEE) during proximal coronary artery bypass graft anastomosis. A 58-year-old man presented to us with a 6-month history of chest pain without any history suggestive of myocardial infarction or transient ischemic attacks. His preoperative echocardiography revealed the systolic dysfunction of LV, mild hypokinesia of basal and mid-anterior wall, and the absence of an aneurysm. He was scheduled for on-pump coronary artery bypass surgery. On intraoperative TEE before establishing cardiopulmonary bypass (CPB), a small immobile mass was found attached to LV apical area. After completion of distal coronary artery grafting, when the aortic cross-clamp was removed, the heart was filled partially and beating spontaneously. TEE examination using 2D mode revealed a free-floating mass in the LV, which was suspected to be a thrombus. Additional navigation using biplane and 3D modes confirmed the presence of the thrombus and distinguished it from papillary muscles and artifact. The surgeon opened the left atrium after re-establishing electromechanical quiescence and removed a thrombus measuring 1.5 cm × 1 cm from the LV. The LV mass in the apical region was no longer seen after discontinuation of CPB. Accurate TEE-detection and timely removal of the thrombus averted disastrous embolic complications. Intraoperative 2D and recent biplane and 3D echocardiography modes are useful monitoring tools during the conduct of CPB. PMID:26440248

  10. A clinical method for mapping and quantifying blood stasis in the left ventricle.

    PubMed

    Rossini, Lorenzo; Martinez-Legazpi, Pablo; Vu, Vi; Fernández-Friera, Leticia; Pérez Del Villar, Candelas; Rodríguez-López, Sara; Benito, Yolanda; Borja, María-Guadalupe; Pastor-Escuredo, David; Yotti, Raquel; Ledesma-Carbayo, María J; Kahn, Andrew M; Ibáñez, Borja; Fernández-Avilés, Francisco; May-Newman, Karen; Bermejo, Javier; Del Álamo, Juan C

    2016-07-26

    In patients at risk of intraventrcular thrombosis, the benefits of chronic anticoagulation therapy need to be balanced with the pro-hemorrhagic effects of therapy. Blood stasis in the cardiac chambers is a recognized risk factor for intracardiac thrombosis and potential cardiogenic embolic events. In this work, we present a novel flow image-based method to assess the location and extent of intraventricular stasis regions inside the left ventricle (LV) by digital processing flow-velocity images obtained either by phase-contrast magnetic resonance (PCMR) or 2D color-Doppler velocimetry (echo-CDV). This approach is based on quantifying the distribution of the blood Residence Time (TR) from time-resolved blood velocity fields in the LV. We tested the new method in illustrative examples of normal hearts, patients with dilated cardiomyopathy and one patient before and after the implantation of a left ventricular assist device (LVAD). The method allowed us to assess in-vivo the location and extent of the stasis regions in the LV. Original metrics were developed to integrate flow properties into simple scalars suitable for a robust and personalized assessment of the risk of thrombosis. From a clinical perspective, this work introduces the new paradigm that quantitative flow dynamics can provide the basis to obtain subclinical markers of intraventricular thrombosis risk. The early prediction of LV blood stasis may result in decrease strokes by appropriate use of anticoagulant therapy for the purpose of primary and secondary prevention. It may also have a significant impact on LVAD device design and operation set-up. PMID:26680013

  11. Coronary collaterals provide a constant scaffold effect on the left ventricle and limit ischemic left ventricular dysfunction in humans

    PubMed Central

    Hoole, Stephen P.; White, Paul A.; Read, Philip A.; Heck, Patrick M.; West, Nick E.; O'Sullivan, Michael

    2012-01-01

    Coronary collaterals preserve left ventricular (LV) function during coronary occlusion by reducing myocardial ischemia and may directly influence LV compliance. We aimed to re-evaluate the relationship between coronary collaterals, measured quantitatively with a pressure wire, and simultaneously recorded LV contractility from conductance catheter data during percutaneous coronary intervention (PCI) in humans. Twenty-five patients with normal LV function awaiting PCI were recruited. Pressure-derived collateral flow index (CFIp): CFIp = (Pw − Pv)/(Pa − Pv) was calculated from pressure distal to coronary balloon occlusion (Pw), central venous pressure (Pv), and aortic pressure (Pa). CFIp was compared with the changes in simultaneously recorded LV end-diastolic pressure (ΔLVEDP), end-diastolic volume, maximum rate of rise in pressure (ΔLVdP/dtmax; systolic function), and time constant of isovolumic relaxation (ΔLV τ; diastolic function), measured by a LV cavity conductance catheter. Measurements were recorded at baseline and following a 1-min coronary occlusion and were duplicated after a 30-min recovery period. There was significant LV diastolic dysfunction following coronary occlusion (ΔLVEDP: +24.5%, P < 0.0001; and ΔLV τ: +20.0%, P < 0.0001), which inversely correlated with CFIp (ΔLVEDP vs. CFIp: r = −0.54, P < 0.0001; ΔLV τ vs. CFIp: r = −0.46, P = 0.0009). Subjects with fewer collaterals had lower LVEDP at baseline (r = 0.33, P = 0.02). CFIp was inversely related to the coronary stenosis pressure gradient at rest (r = −0.31, P = 0.03). Collaterals exert a direct hemodynamic effect on the ventricle and attenuate ischemic LV diastolic dysfunction during coronary occlusion. Vessels with lesions of greater hemodynamic significance have better collateral supply. PMID:22323649

  12. Coronary collaterals provide a constant scaffold effect on the left ventricle and limit ischemic left ventricular dysfunction in humans.

    PubMed

    Hoole, Stephen P; White, Paul A; Read, Philip A; Heck, Patrick M; West, Nick E; O'Sullivan, Michael; Dutka, David P

    2012-04-01

    Coronary collaterals preserve left ventricular (LV) function during coronary occlusion by reducing myocardial ischemia and may directly influence LV compliance. We aimed to re-evaluate the relationship between coronary collaterals, measured quantitatively with a pressure wire, and simultaneously recorded LV contractility from conductance catheter data during percutaneous coronary intervention (PCI) in humans. Twenty-five patients with normal LV function awaiting PCI were recruited. Pressure-derived collateral flow index (CFI(p)): CFI(p) = (P(w) - P(v))/(P(a) - P(v)) was calculated from pressure distal to coronary balloon occlusion (P(w)), central venous pressure (P(v)), and aortic pressure (P(a)). CFI(p) was compared with the changes in simultaneously recorded LV end-diastolic pressure (ΔLVEDP), end-diastolic volume, maximum rate of rise in pressure (ΔLVdP/dt(max); systolic function), and time constant of isovolumic relaxation (ΔLV τ; diastolic function), measured by a LV cavity conductance catheter. Measurements were recorded at baseline and following a 1-min coronary occlusion and were duplicated after a 30-min recovery period. There was significant LV diastolic dysfunction following coronary occlusion (ΔLVEDP: +24.5%, P < 0.0001; and ΔLV τ: +20.0%, P < 0.0001), which inversely correlated with CFI(p) (ΔLVEDP vs. CFI(p): r = -0.54, P < 0.0001; ΔLV τ vs. CFI(p): r = -0.46, P = 0.0009). Subjects with fewer collaterals had lower LVEDP at baseline (r = 0.33, P = 0.02). CFI(p) was inversely related to the coronary stenosis pressure gradient at rest (r = -0.31, P = 0.03). Collaterals exert a direct hemodynamic effect on the ventricle and attenuate ischemic LV diastolic dysfunction during coronary occlusion. Vessels with lesions of greater hemodynamic significance have better collateral supply. PMID:22323649

  13. The influence of coronary angioplasty of the infarct-dependent artery on systolic and diastolic function of the left ventricle.

    PubMed

    Khalilov, Sh D; Guluzade, V U; Alieva, Kh A; Mirzakhanova, L R; Imanov, G G

    2009-01-01

    The target of research is to compare the changes of systolic and diastolic functions of the left ventricle in patients with at least one month infarction after infarct-dependent artery recanalization through elective stenting. The group of 60 patients was selected, 47 men and 13 women, who underwent hospitalization in Central Hospital of Oilworkers in 2006-2007. The investigation was conducted on 30 patients (24 men and 6 women), who underwent elective stenting of LAD. The control group was composed of 30 patients (23 men and 7 women) after anterior myocardial infarction without further stenting of infarct-dependent artery. The clinical diagnosis was confirmed by coronary ventriculography. The patients underwent the echocardiography the day before stenting. The "Sonoline G60 (Siemens, Germany)" machine with 2.5MHz probe has been used. The echocardiography was repeated after 7 days and 3, 6, 12 months after stent implantation. The standard parameters of systolic and diastolic function of the left ventricle were identified during investigation. The statistical processing was delivered through PC with Excel program set. All data are presented in (M+/-m), where the M--mean value, m--standard mean fault. Comparison of the data was conducted with Student criterion. The results of treatment of patients with and without further stenting of infarct-dependent artery were compared. It was found that the stenting of infarct-dependent artery with standard therapy in patients after myocardial infarction has better impact on systolic function, than traditional medical therapy without further reperfusion. The stenting of infarct-dependent artery facilitates earlier improvement of the systolic and diastolic function of the left ventricle. The diastolic relaxation grade of the left ventricle after stenting of the left coronary artery is higher, than in patients without further revascularization. PMID:19644191

  14. Non-invasive assessment of functional strain lines in the real human left ventricle via speckle tracking echocardiography.

    PubMed

    Evangelista, A; Gabriele, S; Nardinocchi, P; Piras, P; Puddu, P E; Teresi, L; Torromeo, C; Varano, V

    2015-02-01

    A mechanics-based analysis of data from three-dimensional speckle tracking echocardiography is proposed, aimed at investigating deformations in myocardium and at assessing shape and function of distinct strain lines corresponding to the principal strain lines of the cardiac tissue. The analysis is based on the application of a protocol of measurement of the endocardial and epicardial principal strain lines, which was already tested on simulated left ventricles. In contrast with similar studies, it is established that endocardial principal strain lines cannot be identified with any structural fibers, not even along the systolic phase and is suggested that it is due to the capacity of the endocardial surface to contrast the dilation of the left ventricle. PMID:25547026

  15. Visualization and simulated surgery of the left ventricle in the virtual pathological heart of the Virtual Physiological Human.

    PubMed

    McFarlane, N J B; Lin, X; Zhao, Y; Clapworthy, G J; Dong, F; Redaelli, A; Parodi, O; Testi, D

    2011-06-01

    Ischaemic heart failure remains a significant health and economic problem worldwide. This paper presents a user-friendly software system that will form a part of the virtual pathological heart of the Virtual Physiological Human (VPH2) project, currently being developed under the European Commission Virtual Physiological Human (VPH) programme. VPH2 is an integrated medicine project, which will create a suite of modelling, simulation and visualization tools for patient-specific prediction and planning in cases of post-ischaemic left ventricular dysfunction. The work presented here describes a three-dimensional interactive visualization for simulating left ventricle restoration surgery, comprising the operations of cutting, stitching and patching, and for simulating the elastic deformation of the ventricle to its post-operative shape. This will supply the quantitative measurements required for the post-operative prediction tools being developed in parallel in the same project. PMID:22670207

  16. Integration of electro-anatomical and imaging data of the left ventricle: An evaluation framework.

    PubMed

    Soto-Iglesias, David; Butakoff, Constantine; Andreu, David; Fernández-Armenta, Juan; Berruezo, Antonio; Camara, Oscar

    2016-08-01

    Integration of electrical and structural information for scar characterization in the left ventricle (LV) is a crucial step to better guide radio-frequency ablation therapies, which are usually performed in complex ventricular tachycardia (VT) cases. This integration requires finding a common representation where to map the electrical information from the electro-anatomical map (EAM) surfaces and tissue viability information from delay-enhancement magnetic resonance images (DE-MRI). However, the development of a consistent integration method is still an open problem due to the lack of a proper evaluation framework to assess its accuracy. In this paper we present both: (i) an evaluation framework to assess the accuracy of EAM and imaging integration strategies with simulated EAM data and a set of global and local measures; and (ii) a new integration methodology based on a planar disk representation where the LV surface meshes are quasi-conformally mapped (QCM) by flattening, allowing for simultaneous visualization and joint analysis of the multi-modal data. The developed evaluation framework was applied to estimate the accuracy of the QCM-based integration strategy on a benchmark dataset of 128 synthetically generated ground-truth cases presenting different scar configurations and EAM characteristics. The obtained results demonstrate a significant reduction in global overlap errors (50-100%) with respect to state-of-the-art integration techniques, also better preserving the local topology of small structures such as conduction channels in scars. Data from seventeen VT patients were also used to study the feasibility of the QCM technique in a clinical setting, consistently outperforming the alternative integration techniques in the presence of sparse and noisy clinical data. The proposed evaluation framework has allowed a rigorous comparison of different EAM and imaging data integration strategies, providing useful information to better guide clinical practice in

  17. The numerical analysis of non-Newtonian blood flow in human patient-specific left ventricle.

    PubMed

    Doost, Siamak N; Zhong, Liang; Su, Boyang; Morsi, Yosry S

    2016-04-01

    Recently, various non-invasive tools such as the magnetic resonance image (MRI), ultrasound imaging (USI), computed tomography (CT), and the computational fluid dynamics (CFD) have been widely utilized to enhance our current understanding of the physiological parameters that affect the initiation and the progression of the cardiovascular diseases (CVDs) associated with heart failure (HF). In particular, the hemodynamics of left ventricle (LV) has attracted the attention of the researchers due to its significant role in the heart functionality. In this study, CFD owing its capability of predicting detailed flow field was adopted to model the blood flow in images-based patient-specific LV over cardiac cycle. In most published studies, the blood is modeled as Newtonian that is not entirely accurate as the blood viscosity varies with the shear rate in non-linear manner. In this paper, we studied the effect of Newtonian assumption on the degree of accuracy of intraventricular hemodynamics. In doing so, various non-Newtonian models and Newtonian model are used in the analysis of the intraventricular flow and the viscosity of the blood. Initially, we used the cardiac MRI images to reconstruct the time-resolved geometry of the patient-specific LV. After the unstructured mesh generation, the simulations were conducted in the CFD commercial solver FLUENT to analyze the intraventricular hemodynamic parameters. The findings indicate that the Newtonian assumption cannot adequately simulate the flow dynamic within the LV over the cardiac cycle, which can be attributed to the pulsatile and recirculation nature of the flow and the low blood shear rate. PMID:26849955

  18. Aberrant Glycosylation in the Left Ventricle and Plasma of Rats with Cardiac Hypertrophy and Heart Failure.

    PubMed

    Nagai-Okatani, Chiaki; Minamino, Naoto

    2016-01-01

    Targeted proteomics focusing on post-translational modifications, including glycosylation, is a useful strategy for discovering novel biomarkers. To apply this strategy effectively to cardiac hypertrophy and resultant heart failure, we aimed to characterize glycosylation profiles in the left ventricle and plasma of rats with cardiac hypertrophy. Dahl salt-sensitive hypertensive rats, a model of hypertension-induced cardiac hypertrophy, were fed a high-salt (8% NaCl) diet starting at 6 weeks. As a result, they exhibited cardiac hypertrophy at 12 weeks and partially impaired cardiac function at 16 weeks compared with control rats fed a low-salt (0.3% NaCl) diet. Gene expression analysis revealed significant changes in the expression of genes encoding glycosyltransferases and glycosidases. Glycoproteome profiling using lectin microarrays indicated upregulation of mucin-type O-glycosylation, especially disialyl-T, and downregulation of core fucosylation on N-glycans, detected by specific interactions with Amaranthus caudatus and Aspergillus oryzae lectins, respectively. Upregulation of plasma α-l-fucosidase activity was identified as a biomarker candidate for cardiac hypertrophy, which is expected to support the existing marker, atrial natriuretic peptide and its related peptides. Proteomic analysis identified cysteine and glycine-rich protein 3, a master regulator of cardiac muscle function, as an O-glycosylated protein with altered glycosylation in the rats with cardiac hypertrophy, suggesting that alternations in O-glycosylation affect its oligomerization and function. In conclusion, our data provide evidence of significant changes in glycosylation pattern, specifically mucin-type O-glycosylation and core defucosylation, in the pathogenesis of cardiac hypertrophy and heart failure, suggesting that they are potential biomarkers for these diseases. PMID:27281159

  19. Aberrant Glycosylation in the Left Ventricle and Plasma of Rats with Cardiac Hypertrophy and Heart Failure

    PubMed Central

    Nagai-Okatani, Chiaki; Minamino, Naoto

    2016-01-01

    Targeted proteomics focusing on post-translational modifications, including glycosylation, is a useful strategy for discovering novel biomarkers. To apply this strategy effectively to cardiac hypertrophy and resultant heart failure, we aimed to characterize glycosylation profiles in the left ventricle and plasma of rats with cardiac hypertrophy. Dahl salt-sensitive hypertensive rats, a model of hypertension-induced cardiac hypertrophy, were fed a high-salt (8% NaCl) diet starting at 6 weeks. As a result, they exhibited cardiac hypertrophy at 12 weeks and partially impaired cardiac function at 16 weeks compared with control rats fed a low-salt (0.3% NaCl) diet. Gene expression analysis revealed significant changes in the expression of genes encoding glycosyltransferases and glycosidases. Glycoproteome profiling using lectin microarrays indicated upregulation of mucin-type O-glycosylation, especially disialyl-T, and downregulation of core fucosylation on N-glycans, detected by specific interactions with Amaranthus caudatus and Aspergillus oryzae lectins, respectively. Upregulation of plasma α-l-fucosidase activity was identified as a biomarker candidate for cardiac hypertrophy, which is expected to support the existing marker, atrial natriuretic peptide and its related peptides. Proteomic analysis identified cysteine and glycine-rich protein 3, a master regulator of cardiac muscle function, as an O-glycosylated protein with altered glycosylation in the rats with cardiac hypertrophy, suggesting that alternations in O-glycosylation affect its oligomerization and function. In conclusion, our data provide evidence of significant changes in glycosylation pattern, specifically mucin-type O-glycosylation and core defucosylation, in the pathogenesis of cardiac hypertrophy and heart failure, suggesting that they are potential biomarkers for these diseases. PMID:27281159

  20. Optimization-Based Speckle Tracking Algorithm for Left Ventricle Strain Estimation: A Feasibility Study.

    PubMed

    Khamis, Hanan; Shimoni, Sara; Hagendorff, Andreas; Smirin, Nahum; Friedman, Zvi; Adam, Dan

    2016-08-01

    Speckle tracking echocardiography (STE) is a widespread method for calculating myocardial strains and estimating left ventricle function. Since echocardiographic clips are corrupted by speckle decorrelation noise, resulting in irregular, nonphysiological tissue displacement fields, smoothing is performed on the displacement data, affecting the strain results. Thus, strain results may depend on the specific implementations of 2-D STE, as well as other systems' characteristics of the various vendors. A novel algorithm (called K-SAD) is introduced, which integrates the physiological constraint of smoothness of the displacement field into an optimization process. Simulated B-mode clips, modeling healthy and abnormal cases, were processed by K-SAD. Peak global and subendocardial longitudinal strains, as well as regional strains, were calculated. In addition, 410 healthy subjects were also processed. The results of K-SAD are compared with those of one of the leading commercial product. K-SAD provides global mid-wall strain values, as well as subendocardial and regional strain values, all in good agreement with the ground-truth-simulated phantom data. K-SAD peak global longitudinal systolic strain values for 410 healthy subjects are quite similar for the different regions: - 17.02 ± 4.02%, - 19.00 ± 3.45%, and - 19.72 ± 5.06% at the basal, mid, and apical regions, respectively. Improved performance under noisy conditions was demonstrated by comparing a subgroup of 40 subjects with the best image quality with the remaining 370 cohort: K-SAD provides statistically similar global and regional results for the two cohorts. Our study indicates that the sensitivity of strain values to speckle noise, caused by the post block-matching weighted smoothing, can be significantly reduced and accuracy enhanced by employing an integrated one-stage, physiologically constrained optimization process. PMID:27214894

  1. Infinite Possibilities for the Finite Element.

    ERIC Educational Resources Information Center

    Finlayson, Bruce A.

    1981-01-01

    Describes the uses of finite element methods in solving problems of heat transfer, fluid flow, etc. Suggests that engineers should know the general concepts and be able to apply the principles of finite element methods. (Author/WB)

  2. Single primitive ventricle with normally related great arteries and atresia of the left A-V valve.

    PubMed Central

    Coto, E O; Raggio, J M; Malo, P; Sainz, C; Aparisi, R; Gomez-Ullate, J M

    1978-01-01

    A child aged 2 years and 9 months was angiocardiographically diagnosed to have a single ventricle with normally related great arteries and atresia of the left A-V valve. A Blalock-Hanlon procedure and division of a large patent ductus arteriosus were followed by reduction in pulmonary artery pressure, but after operation the patient showed signs of left ventricular failure unresponsive to medical treatment, necessitating pulmonary artery banding. We have found only three similar published cases, and this is the only one with full angiographic documentation. Images PMID:725830

  3. Cardiac wound healing post-myocardial infarction: a novel method to target extracellular matrix remodeling in the left ventricle.

    PubMed

    Zamilpa, Rogelio; Zhang, Jianhua; Chiao, Ying Ann; de Castro Brás, Lisandra E; Halade, Ganesh V; Ma, Yonggang; Hacker, Sander O; Lindsey, Merry L

    2013-01-01

    Myocardial infarction (MI) is a leading cause of death worldwide. Permanent ligation of the left anterior descending coronary artery (LAD) is a commonly used surgical model to study post-MI effects in mice. LAD occlusion induces a robust wound healing response that includes extracellular matrix (ECM) remodeling. This chapter provides a detailed guide on the surgical procedure to permanently ligate the LAD. Additionally, we describe a prototype method to enrich cardiac tissue for ECM, which allows one to focus on ECM remodeling in the left ventricle following surgically induced MI in mice. PMID:24029944

  4. The left ventricle as a mechanical engine: from Leonardo da Vinci to the echocardiographic assessment of peak power output-to-left ventricular mass.

    PubMed

    Dini, Frank L; Guarini, Giacinta; Ballo, Piercarlo; Carluccio, Erberto; Maiello, Maria; Capozza, Paola; Innelli, Pasquale; Rosa, Gian M; Palmiero, Pasquale; Galderisi, Maurizio; Razzolini, Renato; Nodari, Savina

    2013-03-01

    The interpretation of the heart as a mechanical engine dates back to the teachings of Leonardo da Vinci, who was the first to apply the laws of mechanics to the function of the heart. Similar to any mechanical engine, whose performance is proportional to the power generated with respect to weight, the left ventricle can be viewed as a power generator whose performance can be related to left ventricular mass. Stress echocardiography may provide valuable information on the relationship between cardiac performance and recruited left ventricular mass that may be used in distinguishing between adaptive and maladaptive left ventricular remodeling. Peak power output-to-mass, obtained during exercise or pharmacological stress echocardiography, is a measure that reflects the number of watts that are developed by 100 g of left ventricular mass under maximal stimulation. Power output-to-mass may be calculated as left ventricular power output per 100 g of left ventricular mass: 100× left ventricular power output divided by left ventricular mass (W/100 g). A simplified formula to calculate power output-to-mass is as follows: 0.222 × cardiac output (l/min) × mean blood pressure (mmHg)/left ventricular mass (g). When the integrity of myocardial structure is compromised, a mismatch becomes apparent between maximal cardiac power output and left ventricular mass; when this occurs, a reduction of the peak power output-to-mass index is observed. PMID:21934524

  5. Lactate clearance for initiating and weaning off extracorporeal membrane oxygenation in a child with regressed left ventricle after arterial switch operation

    PubMed Central

    Singh, Sarvesh Pal; Chauhan, Sandeep; Bisoi, A. K.; Sahoo, Manoj

    2016-01-01

    We hereby report a child with transposition of great arteries and regressed ventricle who underwent arterial switch operation (ASO) with the aid of cardiopulmonary bypass and “integrated” extracorporeal membrane oxygenation (ECMO) circuit. The significance of lactate clearance as a guide to initiate and terminate veno-arterial ECMO in a post ASO child with regressed left ventricle is discussed. PMID:26750700

  6. Peridynamic Multiscale Finite Element Methods

    SciTech Connect

    Costa, Timothy; Bond, Stephen D.; Littlewood, David John; Moore, Stan Gerald

    2015-12-01

    The problem of computing quantum-accurate design-scale solutions to mechanics problems is rich with applications and serves as the background to modern multiscale science research. The prob- lem can be broken into component problems comprised of communicating across adjacent scales, which when strung together create a pipeline for information to travel from quantum scales to design scales. Traditionally, this involves connections between a) quantum electronic structure calculations and molecular dynamics and between b) molecular dynamics and local partial differ- ential equation models at the design scale. The second step, b), is particularly challenging since the appropriate scales of molecular dynamic and local partial differential equation models do not overlap. The peridynamic model for continuum mechanics provides an advantage in this endeavor, as the basic equations of peridynamics are valid at a wide range of scales limiting from the classical partial differential equation models valid at the design scale to the scale of molecular dynamics. In this work we focus on the development of multiscale finite element methods for the peridynamic model, in an effort to create a mathematically consistent channel for microscale information to travel from the upper limits of the molecular dynamics scale to the design scale. In particular, we first develop a Nonlocal Multiscale Finite Element Method which solves the peridynamic model at multiple scales to include microscale information at the coarse-scale. We then consider a method that solves a fine-scale peridynamic model to build element-support basis functions for a coarse- scale local partial differential equation model, called the Mixed Locality Multiscale Finite Element Method. Given decades of research and development into finite element codes for the local partial differential equation models of continuum mechanics there is a strong desire to couple local and nonlocal models to leverage the speed and state of the

  7. [Demonstration of obstruction of blood outflow from the left and right ventricles in idiopathic hypertrophic subaortic stenosis].

    PubMed

    Makhkamova, M N

    1985-12-01

    A comparative assessment of the value of routine clinical and intracardiac investigation procedures for the diagnosis of idiopathic hypertrophic subaortic stenosis (IHSS) was carried out in 12 patients with simultaneous obstructions of the left- and right-ventricular blood outflow pathways caused by hypertrophy of the interventricular septum. It is suggested that electrocardiographic and roentgenologic evidence of overloaded right and left compartments of the heart signals are indicative of the need for simultaneous catheterization and angiocardiography of the right and left compartments that can detect right-ventricular obstruction in the IHSS patients. Intravital diagnosis of the obstruction makes possible complete correction of the defect, whereas an isolated removal of the left-ventricular obstruction is not successful in the presence of an obstruction in the right ventricle. PMID:2936921

  8. A level set approach for left ventricle detection in CT images using shape segmentation and optical flow

    NASA Astrophysics Data System (ADS)

    Brieva, Jorge; Moya-Albor, Ernesto; Escalante-Ramírez, Boris

    2015-01-01

    The left ventricle (LV) segmentation plays an important role in a subsequent process for the functional analysis of the LV. Typical segmentation of the endocardium wall in the ventricle excludes papillary muscles which leads to an incorrect measure of the ejected volume in the LV. In this paper we present a new variational strategy using a 2D level set framework that includes a local term for enhancing the low contrast structures and a 2D shape model. The shape model in the level set method is propagated to all image sequences corresponding to the cardiac cycles through the optical flow approach using the Hermite transform. To evaluate our strategy we use the Dice index and the Hausdorff distance to compare the segmentation results with the manual segmentation carried out by the physician.

  9. Automatic segmentation of the left ventricle and computation of diagnostic parameters using regiongrowing and a statistical model

    NASA Astrophysics Data System (ADS)

    Fritz, Dominik; Rinck, Daniel; Unterhinninghofen, Roland; Dillmann, Ruediger; Scheuering, Michael

    2005-04-01

    The manual segmentation and analysis of high-resolution multi-slice cardiac CT datasets is both labor intensive and time consuming. Therefore it is necessary to supply the cardiologist with powerful software tools to segment the myocardium and compute the relevant diagnostic parameters. In this work we present an semi-automatic cardiac segmentation approach with minimal user interaction. It is based on a combination of an adaptive slice-based regiongrowing and a modified Active Shape Model (ASM). Starting with a single manual click point in the ascending aorta, the aorta, the left atrium and the left ventricle get segmented with the slice-based adaptive regiongrowing. The approximate position of the aortic and mitral valve as well as the principal axes of the left ventricle (LV) are determined. To prevent the regiongrowing from draining into neighboring anatomical structures via CT artifacts, we implemented a draining control by examining a cubic region around the currently processed voxel. Additionally, we use moment-based parameters to integrate simple anatomical knowledge into the regiongrowing process. Using the results of the preceding regiongrowing process, a ventricle-centric and normalized coordinate system is established which is used to adapt a previously trained ASM to the image, using an iterative multi-resolution approach. After fitting the ASM to the image, we can use the generated model-points to create an exact surface model of the left ventricular myocardium for visualization and for computing the diagnostically relevant parameters, like the ventricular blood volume and the myocardial wall thickness.

  10. Endocardial left ventricle feature tracking and reconstruction from tri-plane trans-esophageal echocardiography data

    NASA Astrophysics Data System (ADS)

    Dangi, Shusil; Ben-Zikri, Yehuda K.; Cahill, Nathan; Schwarz, Karl Q.; Linte, Cristian A.

    2015-03-01

    Two-dimensional (2D) ultrasound (US) has been the clinical standard for over two decades for monitoring and assessing cardiac function and providing support via intra-operative visualization and guidance for minimally invasive cardiac interventions. Developments in three-dimensional (3D) image acquisition and transducer design and technology have revolutionized echocardiography imaging enabling both real-time 3D trans-esophageal and intra-cardiac image acquisition. However, in most cases the clinicians do not access the entire 3D image volume when analyzing the data, rather they focus on several key views that render the cardiac anatomy of interest during the US imaging exam. This approach enables image acquisition at a much higher spatial and temporal resolution. Two such common approaches are the bi-plane and tri-plane data acquisition protocols; as their name states, the former comprises two orthogonal image views, while the latter depicts the cardiac anatomy based on three co-axially intersecting views spaced at 600 to one another. Since cardiac anatomy is continuously changing, the intra-operative anatomy depicted using real-time US imaging also needs to be updated by tracking the key features of interest and endocardial left ventricle (LV) boundaries. Therefore, rapid automatic feature tracking in US images is critical for three reasons: 1) to perform cardiac function assessment; 2) to identify location of surgical targets for accurate tool to target navigation and on-target instrument positioning; and 3) to enable pre- to intra-op image registration as a means to fuse pre-op CT or MR images used during planning with intra-operative images for enhanced guidance. In this paper we utilize monogenic filtering, graph-cut based segmentation and robust spline smoothing in a combined work flow to process the acquired tri-plane TEE time series US images and demonstrate robust and accurate tracking of the LV endocardial features. We reconstruct the endocardial LV

  11. Systemic or Endoventricular Thrombolysis to Treat HeartWare Left Ventricle Assist Device Thrombosis: A Clinical Dilemma.

    PubMed

    Raffa, Giuseppe M; D'Ancona, Giuseppe; Sciacca, Sergio; Pietrosi, Astrid; Hernandez Baravoglia, Cesar M; Turrisi, Marco; Romano, Giuseppe; Armaro, Alessandro; Stringi, Vincenzo; Clemenza, Francesco; Pilato, Michele

    2015-06-01

    Endoventricular thrombolytic procedure (ETP) has been used to treat continuous-flow left ventricle assist device (CF-LVAD) thrombosis. The study aims to investigate the occurrence of complications after ETP. Data were retrospectively reviewed and analyzed in a series of patients who underwent CF-LVAD followed by ETP. Since November 2010, 20 patients underwent HeartWare CF-LVAD implantation at our institute. Four patients (20%) developed pump thrombosis and underwent a total of nine ETPs with tissue plasminogen activator infused into the left ventricle. The mean age was 60.2 ± 9 years. ETP was performed via either the femoral (n = 6) or radial artery (n = 3). Five ETPs (55.5%) were complicated by left and right radial artery occlusion, two by groin hematomas, and one by femoral artery false aneurysm. ETP carries a strong risk of vascular access complications that, in CF-LVAD patients, may add to the already complex clinical profile and economic burden; thus, a less invasive treatment is advisable whenever required. PMID:25735566

  12. Catheter-based high-intensity ultrasound for epicardial ablation of the left ventricle: device design and in vivo feasiblity

    NASA Astrophysics Data System (ADS)

    Salgaonkar, Vasant A.; Nazer, Babak; Jones, Peter D.; Tanaka, Yasuaki; Martin, Alastair; Ng, Bennett; Duggirala, Srikant; Diederich, Chris J.; Gerstenfeld, Edward P.

    2015-03-01

    The development and in vivo testing of a high-intensity ultrasound thermal ablation catheter for epicardial ablation of the left ventricle (LV) is presented. Scar tissue can occur in the mid-myocardial and epicardial space in patients with nonischemic cardiomyopathy and lead to ventricular tachycardia. Current ablation technology uses radiofrequency energy, which is limited epicardially by the presence of coronary vessels, phrenic nerves, and fat. Ultrasound energy can be precisely directed to deliver targeted deep epicardial ablation while sparing intervening epicardial nerve and vessels. The proof-of-concept ultrasound applicators were designed for sub-xyphoid access to the pericardial space through a steerable 14-Fr sheath. The catheter consists of two rectangular planar transducers, for therapy (6.4 MHz) and imaging (5 MHz), mounted at the tip of a 3.5-mm flexible nylon catheter coupled and encapsulated within a custom-shaped balloon for cooling. Thermal lesions were created in the LV in a swine (n = 10) model in vivo. The ultrasound applicator was positioned fluoroscopically. Its orientation and contact with the LV were verified using A-mode imaging and a radio-opaque marker. Ablations employed 60-s exposures at 15 - 30 W (electrical power). Histology indicated thermal coagulation and ablative lesions penetrating 8 - 12 mm into the left ventricle on lateral and anterior walls and along the left anterior descending artery. The transducer design enabled successful sparing from the epicardial surface to 2 - 4 mm of intervening ventricle tissue and epicardial fat. The feasibility of targeted epicardial ablation with catheter-based ultrasound was demonstrated.

  13. Ectopia cordis with a double outlet right ventricle, large ventricular septal defect, malposed great arteries and left ventricular hypoplasia.

    PubMed

    Malik, Rabiya; Zilberman, Mark V; Tang, Liwen; Miller, Susan; Pandian, Natesa G

    2015-03-01

    Ectopia cordis, defined as partial or complete displacement of the heart outside of the thoracic cavity, is a rare congenital malformation. If not surgically corrected during the early years of life, ectopia cordis can prove to be a fatal abnormality. However, due to the presence of multiple intracardiac and extracardiac malformations, a corrective surgery might not always be successful. The pathology of ectopia cordis with a double outlet right ventricle, large ventricular septal defect, malposed great arteries and left ventricular hypoplasia is discussed, highlighting the complexities involved in such a rare disorder. PMID:25409882

  14. Domain decomposition methods for mortar finite elements

    SciTech Connect

    Widlund, O.

    1996-12-31

    In the last few years, domain decomposition methods, previously developed and tested for standard finite element methods and elliptic problems, have been extended and modified to work for mortar and other nonconforming finite element methods. A survey will be given of work carried out jointly with Yves Achdou, Mario Casarin, Maksymilian Dryja and Yvon Maday. Results on the p- and h-p-version finite elements will also be discussed.

  15. Finite element methods in numerical relativity.

    NASA Astrophysics Data System (ADS)

    Mann, P. J.

    The finite element method is very successful in Newtonian fluid simulations, and can be extended to relativitstic fluid flows. This paper describes the general method, and then outlines some preliminary results for spherically symmetric geometries. The mixed finite element - finite difference scheme is introduced, and used for the description of spherically symmetric collapse. Baker's (Newtonian) shock modelling method and Miller's moving finite element method are also mentioned. Collapse in double-null coordinates requires non-constant time slicing, so the full finite element method in space and time is described.

  16. ANSYS duplicate finite-element checker routine

    NASA Technical Reports Server (NTRS)

    Ortega, R.

    1995-01-01

    An ANSYS finite-element code routine to check for duplicated elements within the volume of a three-dimensional (3D) finite-element mesh was developed. The routine developed is used for checking floating elements within a mesh, identically duplicated elements, and intersecting elements with a common face. A space shuttle main engine alternate turbopump development high pressure oxidizer turbopump finite-element model check using the developed subroutine is discussed. Finally, recommendations are provided for duplicate element checking of 3D finite-element models.

  17. T3 enhances Ang2 in rat aorta in myocardial I/R: comparison with left ventricle.

    PubMed

    Sabatino, Laura; Kusmic, Claudia; Nicolini, Giuseppina; Amato, Rosario; Casini, Giovanni; Iervasi, Giorgio; Balzan, Silvana

    2016-10-01

    Angiogenesis is important for recovery after tissue damage in myocardial ischemia/reperfusion, and tri-iodothyronine (T3) has documented effects on angiogenesis. The angiopoietins 1/2 and tyrosine kinase receptor represent an essential system in angiogenesis controlling endothelial cell survival and vascular maturation. Recently, in a 3-day ischemia/reperfusion rat model, the infusion of a low dose of T3 improved the post-ischemic recovery of cardiac function.Adopting this model, our study aimed to investigate the effects of T3 on the capillary index and the expression of angiogenic genes as the angiopoietins 1/2 and tyrosine kinase receptor system, in the thoracic aorta and in the left ventricle. In the thoracic aorta, T3 infusion significantly improved the angiogenic sprouting and angiopoietin 2 expression. Instead, Sham-T3 group did not show any significant increment of capillary density and angiopoietin 2 expression. In the area at risk (AAR) of the left ventricle, T3 infusion did not increase capillary density but restored levels of angiopoietin 1, which were reduced in I/R group. Angiopoietin 2 levels were similar to Sham group and unchanged by T3 administration. In the remote zone, T3 induced a significant increment of both angiopoietin 1/2. In conclusion, T3 infusion induced a different response of angiopoietin 1/2 between the ventricle (the AAR and the remote zone) and the thoracic aorta, probably reflecting the different action of angiopoietin 1/2 in cardiomyocytes and endothelial cells. Overall, these data suggest a new aspect of T3-mediated cardioprotection through angiogenesis. PMID:27444191

  18. Computational modeling of Takotsubo cardiomyopathy: effect of spatially varying β-adrenergic stimulation in the rat left ventricle

    PubMed Central

    Land, Sander; Niederer, Steven A.; Louch, William E.; Røe, Åsmund T.; Aronsen, Jan Magnus; Stuckey, Daniel J.; Sikkel, Markus B.; Tranter, Matthew H.; Lyon, Alexander R.; Harding, Sian E.

    2014-01-01

    In Takotsubo cardiomyopathy, the left ventricle shows apical ballooning combined with basal hypercontractility. Both clinical observations in humans and recent experimental work on isolated rat ventricular myocytes suggest the dominant mechanisms of this syndrome are related to acute catecholamine overload. However, relating observed differences in single cells to the capacity of such alterations to result in the extreme changes in ventricular shape seen in Takotsubo syndrome is difficult. By using a computational model of the rat left ventricle, we investigate which mechanisms can give rise to the typical shape of the ventricle observed in this syndrome. Three potential dominant mechanisms related to effects of β-adrenergic stimulation were considered: apical-basal variation of calcium transients due to differences in L-type and sarco(endo)plasmic reticulum Ca2+-ATPase activation, apical-basal variation of calcium sensitivity due to differences in troponin I phosphorylation, and apical-basal variation in maximal active tension due to, e.g., the negative inotropic effects of p38 MAPK. Furthermore, we investigated the interaction of these spatial variations in the presence of a failing Frank-Starling mechanism. We conclude that a large portion of the apex needs to be affected by severe changes in calcium regulation or contractile function to result in apical ballooning, and smooth linear variation from apex to base is unlikely to result in the typical ventricular shape observed in this syndrome. A failing Frank-Starling mechanism significantly increases apical ballooning at end systole and may be an important additional factor underpinning Takotsubo syndrome. PMID:25239804

  19. [Echocardiographic triangular pattern of the mitral valve during acute pressure overload of the left ventricle: an experimental study].

    PubMed

    Tanimoto, M; Yamamoto, T; Kimura, S; Komasa, N; Makihata, S; Yasutomi, N; Saito, Y; Kawai, Y; Iwasaki, T

    1982-03-01

    The changes of mitral valve echo and hemodynamic data [isovolumic relaxation time (IRT)/square root R-R, time constant T, peak positive dP/dt/P, left ventricular enddiastolic pressure (LVEDP) and left ventricular systolic pressure (LVSP] during acute pressure overload produced by aortic root obstruction were analyzed in 13 mongrel dogs under sodium pentbarbital anesthesia (25 mg/kg). IRT/square root R-R, time constant T, positive dP/dt and LVSP were expressed as percent changes to the value (=100%) of pre-pressure overload, LVEDP was expressed by an absolute value as mmHg. In 7 of 13 dogs, an abnormal diastolic monophasic triangular pattern of the mitral valve was observed during acute pressure overload of the left ventricle, and values of five hemodynamic data were compared between cases with or without the triangular pattern. The values of IRT/square root R-R, time constant T, positive dP/dt/P, LVSP amd LVEDP in cases with the triangular pattern became from 200 to 500% (275 +/- 100%), from 175 to 267% (220 +/- 50%), from 55 to 112% (81 +/- 21%), from 129 to 200% (59 +/- 21%) and from 7 to 33 mmHg (16 +/- 9 mmHg), respectively. The values of IRT/square root R-R, time constant T, positive dP/dt/P, LVSP and LVEDP in cases with the non-triangular pattern became from 116 to 155% (133 +/- 17%), from 116 to 154% (136 +/- 16%), from 111 to 186% (62 +/- 34%) and from 9 to 20 mmHg (9 +/- 6 mmHg), respectively. Thus, the values of IRT/square root R-R and time constant T were significantly different between the two groups. The possible explanation for the triangular pattern of the mitral valve seems to be due to impaired active relaxation system of the left ventricle resulting in a markedly delayed opening of the mitral valve. We conclude that early diastolic isovolumic relaxation of the left ventricle is impaired by acute pressure overload, and the echocardiographic diastolic monophasic triangular pattern of the mitral valve reflects this impairment. PMID:7119493

  20. Double Outlet Right Ventricle

    MedlinePlus

    ... the right ventricle into the lungs, and the aorta sends oxygen-rich blood from the left ventricle ... the body. Together, the pulmonary artery and the aorta are known as the great arteries. But with ...

  1. Shape regression machine and efficient segmentation of left ventricle endocardium from 2D B-mode echocardiogram.

    PubMed

    Zhou, Shaohua Kevin

    2010-08-01

    We present a machine learning approach called shape regression machine (SRM) for efficient segmentation of an anatomic structure that exhibits a deformable shape in a medical image, e.g., left ventricle endocardial wall in an echocardiogram. The SRM achieves efficient segmentation via statistical learning of the interrelations among shape, appearance, and anatomy, which are exemplified by an annotated database. The SRM is a two-stage approach. In the first stage that estimates a rigid shape to solve an automatic initialization problem, it derives a regression solution to object detection that needs just one scan in principle and a sparse set of scans in practice, avoiding the exhaustive scanning required by the state-of-the-art classification-based detection approach while yielding comparable detection accuracy. In the second stage that estimates the nonrigid shape, it again learns a nonlinear regressor to directly associate nonrigid shape with image appearance. The underpinning of both stages is a novel image-based boosting ridge regression (IBRR) method that enables multivariate, nonlinear modeling and accommodates fast evaluation. We demonstrate the efficiency and effectiveness of the SRM using experiments on segmenting the left ventricle endocardium from a B-mode echocardiogram of apical four chamber view. The proposed algorithm is able to automatically detect and accurately segment the LV endocardial border in about 120ms. PMID:20494610

  2. Probabilistic finite element analysis of a craniofacial finite element model.

    PubMed

    Berthaume, Michael A; Dechow, Paul C; Iriarte-Diaz, Jose; Ross, Callum F; Strait, David S; Wang, Qian; Grosse, Ian R

    2012-05-01

    We employed a probabilistic finite element analysis (FEA) method to determine how variability in material property values affects stress and strain values in a finite model of a Macaca fascicularis cranium. The material behavior of cortical bone varied in three ways: isotropic homogeneous, isotropic non-homogeneous, and orthotropic non-homogeneous. The material behavior of the trabecular bone and teeth was always treated as isotropic and homogeneous. All material property values for the cranium were randomized with a Gaussian distribution with either coefficients of variation (CVs) of 0.2 or with CVs calculated from empirical data. Latin hypercube sampling was used to determine the values of the material properties used in the finite element models. In total, four hundred and twenty six separate deterministic FE simulations were executed. We tested four hypotheses in this study: (1) uncertainty in material property values will have an insignificant effect on high stresses and a significant effect on high strains for homogeneous isotropic models; (2) the effect of variability in material property values on the stress state will increase as non-homogeneity and anisotropy increase; (3) variation in the in vivo shear strain values reported by Strait et al. (2005) and Ross et al. (2011) is not only due to variations in muscle forces and cranial morphology, but also due to variation in material property values; (4) the assumption of a uniform coefficient of variation for the material property values will result in the same trend in how moderate-to-high stresses and moderate-to-high strains vary with respect to the degree of non-homogeneity and anisotropy as the trend found when the coefficients of variation for material property values are calculated from empirical data. Our results supported the first three hypotheses and falsified the fourth. When material properties were varied with a constant CV, as non-homogeneity and anisotropy increased the level of variability in

  3. Early genes induction in spontaneously hypertensive rats left ventricle with angiotensin-converting enzyme inhibitors but not hydralazine

    SciTech Connect

    Susic, D.; Aristizabal, D.J.; Prakash, O.; Nunez, E.; Frohlich, E.D.

    1995-12-01

    Spontaneously hypertensive rats were given an angiotensin-converting enzyme (ACE) inhibitor (benazepril or quinapril) or hydralazine and were left for up to 6 hr. To examine whether administration of antihypertensive agents affects expression of immediate early genes in left ventricular myocardium, groups of rats were sacrificed at 1, 3, and 6 hr after dosing; total RNA was extracted from left ventricular tissue and analyzed by blot hybridization technique using labeled probes for c-myc, c-fos, and GAPDH mRNA. All three antihypertensive agents reduced pressure similarly, and treatment with the two ACE inhibitors increased c-fos and c-myc mRNA expression in left ventriculum. By contrast, hydralazine did not increase steady-state mRNA expression of either proto-oncogene. Thus, in parallel with the pressure fall, acute administration of the ACE inhibitors induced expression of c-fos and c-myc mRNAs in the left ventricle. Since the equidepressor dose of hyralazine did not affect expression of these proto-oncogenes, this effect of ACE inhibitors is independent of their hemodynamic action. 27 refs., 1 fig., 2 tabs.

  4. FEBio: finite elements for biomechanics.

    PubMed

    Maas, Steve A; Ellis, Benjamin J; Ateshian, Gerard A; Weiss, Jeffrey A

    2012-01-01

    In the field of computational biomechanics, investigators have primarily used commercial software that is neither geared toward biological applications nor sufficiently flexible to follow the latest developments in the field. This lack of a tailored software environment has hampered research progress, as well as dissemination of models and results. To address these issues, we developed the FEBio software suite (http://mrl.sci.utah.edu/software/febio), a nonlinear implicit finite element (FE) framework, designed specifically for analysis in computational solid biomechanics. This paper provides an overview of the theoretical basis of FEBio and its main features. FEBio offers modeling scenarios, constitutive models, and boundary conditions, which are relevant to numerous applications in biomechanics. The open-source FEBio software is written in C++, with particular attention to scalar and parallel performance on modern computer architectures. Software verification is a large part of the development and maintenance of FEBio, and to demonstrate the general approach, the description and results of several problems from the FEBio Verification Suite are presented and compared to analytical solutions or results from other established and verified FE codes. An additional simulation is described that illustrates the application of FEBio to a research problem in biomechanics. Together with the pre- and postprocessing software PREVIEW and POSTVIEW, FEBio provides a tailored solution for research and development in computational biomechanics. PMID:22482660

  5. Finite element coiled cochlea model

    NASA Astrophysics Data System (ADS)

    Isailovic, Velibor; Nikolic, Milica; Milosevic, Zarko; Saveljic, Igor; Nikolic, Dalibor; Radovic, Milos; Filipović, Nenad

    2015-12-01

    Cochlea is important part of the hearing system, and thanks to special structure converts external sound waves into neural impulses which go to the brain. Shape of the cochlea is like snail, so geometry of the cochlea model is complex. The simplified cochlea coiled model was developed using finite element method inside SIFEM FP7 project. Software application is created on the way that user can prescribe set of the parameters for spiral cochlea, as well as material properties and boundary conditions to the model. Several mathematical models were tested. The acoustic wave equation for describing fluid in the cochlea chambers - scala vestibuli and scala timpani, and Newtonian dynamics for describing vibrations of the basilar membrane are used. The mechanical behavior of the coiled cochlea was analyzed and the third chamber, scala media, was not modeled because it does not have a significant impact on the mechanical vibrations of the basilar membrane. The obtained results are in good agreement with experimental measurements. Future work is needed for more realistic geometry model. Coiled model of the cochlea was created and results are compared with initial simplified coiled model of the cochlea.

  6. Successful Operative Repair of Delayed Left Ventricle Rupture From Blunt Trauma.

    PubMed

    Greene, Christina L; Boyd, Jack H

    2016-08-01

    A 21-year-old female was found to have an enlarging pericardial effusion 10 days after a 40-foot fall. Initial cardiac evaluation was negative. Ten days after presentation she developed hemodynamic compromise and chest computed tomography was concerning for cardiac rupture. The patient was taken to the operating room where the ruptured posterior ventricle was repaired, perforation in the P1 leaflet was identified and the mitral valve was replaced. The patient survived. To our knowledge, this is the first report of survival after delayed presentation of atrioventricular rupture at the level of the mitral valve. PMID:27449439

  7. Application of a PExSim for modeling a POLVAD artificial heart and the human circulatory system with left ventricle assistance

    NASA Astrophysics Data System (ADS)

    Siewnicka, Alicja; Fajdek, Bartlomiej; Janiszowski, Krzysztof

    2010-01-01

    This paper presents a model of the human circulatory system with the possible addition of a parallel assist device, which was developed for the purpose of artificial heart monitoring. Information about an identification experiment of an extracorporeal ventricle assist device POLVAD is included. The modelling methods applied and the corresponding functional blocks in a PExSim package are presented. The results of the simulation for physiological conditions, left ventricle failure and pathological conditions with parallel assistance are included.

  8. Automatic localization of the left ventricle from cardiac cine magnetic resonance imaging: a new spectrum-based computer-aided tool.

    PubMed

    Zhong, Liang; Zhang, Jun-Mei; Zhao, Xiaodan; Tan, Ru San; Wan, Min

    2014-01-01

    Traditionally, cardiac image analysis is done manually. Automatic image processing can help with the repetitive tasks, and also deal with huge amounts of data, a task which would be humanly tedious. This study aims to develop a spectrum-based computer-aided tool to locate the left ventricle using images obtained via cardiac magnetic resonance imaging. Discrete Fourier Transform was conducted pixelwise on the image sequence. Harmonic images of all frequencies were analyzed visually and quantitatively to determine different patterns of the left and right ventricles on spectrum. The first and fifth harmonic images were selected to perform an anisotropic weighted circle Hough detection. This tool was then tested in ten volunteers. Our tool was able to locate the left ventricle in all cases and had a significantly higher cropping ratio of 0.165 than did earlier studies. In conclusion, a new spectrum-based computer aided tool has been proposed and developed for automatic left ventricle localization. The development of this technique, which will enable the automatic location and further segmentation of the left ventricle, will have a significant impact in research and in diagnostic settings. We envisage that this automated method could be used by radiographers and cardiologists to diagnose and assess ventricular function in patients with diverse heart diseases. PMID:24722328

  9. Impact of Continuous Erythropoietin Receptor Activator on Selected Biomarkers of Cardiovascular Disease and Left Ventricle Structure and Function in Chronic Kidney Disease

    PubMed Central

    Rysz, Jacek; Franczyk, Beata; Baj, Zbigniew; Majewska, Ewa

    2016-01-01

    Background. Cardiovascular morbidity and mortality are very high in patients with chronic kidney disease (CKD). The purpose of this study is to evaluate the impact of continuous erythropoietin receptor activator (CERA) on selected biomarkers of cardiovascular disease, left ventricle structure, and function in CKD. Material and Methods. Peripheral blood was collected from 25 CKD patients before and after CERA treatment and 20 healthy subjects. In serum samples, we assessed inflammatory markers (IL-1β, TNF-RI, TNF-RII, sFas, sFasL, MMP-9, TIMP-1, and TGF-β1), endothelial dysfunction markers (sE-selectin, sICAM-1, and sVCAM-1), and volume-related marker (NT-proBNP). All subjects underwent echocardiography and were evaluated for selected biochemical parameters (Hb, creatinine, and CRP). Results. Evaluated biomarkers and echocardiographic parameters of left ventricle structure were significantly increased but left ventricle EF was significantly decreased in CKD patients compared to controls. After CERA treatment, we observed a significant increase of Hb and left ventricle EF and a significant decrease of NT-proBNP and MMP-9. There was a significant negative correlation between Hb and TNF-RI, sICAM-1, and IL-1β. Conclusions. Our results indicate that selected biomarkers related to cardiovascular risk are significantly increased in CKD patients compared to controls. CERA treatment has anti-inflammatory action, diminishes endothelial dysfunction, and improves left ventricle function in these patients. PMID:27034745

  10. Graphics for Finite-Element Analysis

    NASA Technical Reports Server (NTRS)

    Thornton, E. A.; Sawyer, L. M.

    1982-01-01

    ELPLOT program is a passive computer graphics system that could be utilized for display of models and responses of general finite-element analyses. Program includes: Wide range of view-orientation selections, number of alternative data-input formats, extensive family of finite-element types, and capabilities for both static and dynamic-response displays.

  11. 3-D Finite Element Code Postprocessor

    Energy Science and Technology Software Center (ESTSC)

    1996-07-15

    TAURUS is an interactive post-processing application supporting visualization of finite element analysis results on unstructured grids. TAURUS provides the ability to display deformed geometries and contours or fringes of a large number of derived results on meshes consisting of beam, plate, shell, and solid type finite elements. Time history plotting is also available.

  12. Finite-Element Composite-Analysis Program

    NASA Technical Reports Server (NTRS)

    Bowles, David E.

    1990-01-01

    Finite Element Composite Analysis Program, FECAP, special-purpose finite-element program for analyzing behavior of composite material with microcomputer. Procedure leads to set of linear simultaneous equations relating unknown nodal displacement to applied loads. Written in HP BASIC 3.0.

  13. Finite element analysis of helicopter structures

    NASA Technical Reports Server (NTRS)

    Rich, M. J.

    1978-01-01

    Application of the finite element analysis is now being expanded to three dimensional analysis of mechanical components. Examples are presented for airframe, mechanical components, and composite structure calculations. Data are detailed on the increase of model size, computer usage, and the effect on reducing stress analysis costs. Future applications for use of finite element analysis for helicopter structures are projected.

  14. Parametric ultrasound and fluoroscopy image fusion for guidance of left ventricle lead placement in cardiac resynchronization therapy.

    PubMed

    Babic, Aleksandar; Odland, Hans Henrik; Gérard, Olivier; Samset, Eigil

    2015-04-01

    Recent studies show that the response rate to cardiac resynchronization therapy (CRT) could be improved if the left ventricle (LV) is paced at the site of the latest mechanical activation, but away from the myocardial scar. A prototype system for CRT lead placement guidance that combines LV functional information from ultrasound with live x-ray fluoroscopy was developed. Two mean anatomical models, each containing LV epi-, LV endo- and right ventricle endocardial surfaces, were computed from a database of 33 heart failure patients as a substitute for a patient-specific model. The sphericity index was used to divide the observed population into two groups. The distance between the mean and the patient-specific models was determined using a signed distance field metric (reported in mm). The average error values for LV epicardium were [Formula: see text] and for LV endocardium were [Formula: see text]. The validity of using average LV models for a CRT procedure was tested by simulating coronary vein selection in a group of 15 CRT candidates. The probability of selecting the same coronary branch, when basing the selection on the average model compared to a patient-specific model, was estimated to be [Formula: see text]. This was found to be clinically acceptable. PMID:26158110

  15. Influence of the heart rate and atrioventricular delays on vortex evolution and blood transport inside the left ventricle

    NASA Astrophysics Data System (ADS)

    Hendabadi, Sahar; Martinez-Legazpi, Pablo; Benito, Yolanda; Bermejo, Javier; Del Alamo, Juan Carlos; Shadden, Shawn

    2013-11-01

    Cardiac resynchronization therapy (CRT) is used to help restore coordinated pumping of the ventricles by overcoming delays in electrical conduction due to cardiac disease. This is accomplished by a specialized cardiac pacemaker that is able to adjust the atrioventricular (AV) delay.A major clinical challenge is to adjust the pacing strategy to best coordinate the blood flow mechanics of ventricular filling and ejection. To this end, we have studied the difference in the vortex formation and its evolution inside the left ventricle (LV) for 4 different AV delays in a cohort of patients with implanted pacemakers. A reconstruction algorithm was used to obtain 2D velocity over the apical long-axis view of the LV from color Doppler and B-mode ultrasound data. To study blood transport, we have identified Lagrangian coherent structures to determine moving boundaries of the blood volumes injected to the LV in diastole and ejected to the aorta in systole. In all cases, we have analyzed the differences in filling and ejection patterns and the blood transport during the E-wave and A-wave formation.Finally we have assessed the influence of the AV delay on 2 indices of stasis, direct flow and residence time.The findings shed insight to the optimization of AV delays in patients undergoing CRT. NIH award 5R21HL108268 and grants PIS09/02603 and RD06/0010 from the Plan Nacional de Investigacion Cientifica, Spain.

  16. Automated Classification of Disease Patterns from Echo-cardiography Images Based on Shape Features of the Left Ventricle

    NASA Astrophysics Data System (ADS)

    Das, Shaoli; Parekh, Ranjan

    2010-10-01

    Computer assisted diagnosis using analysis of medical images is an area of active research in health informatics. This paper proposes a technique for indication of heart diseases by using information related to shapes of the left ventricle (LV). LV boundaries are tracked from echo-cardiography images taken from LV short axis view, corresponding to two disease conditions viz. dilated cardiomyopathy and hypertrophic cardiomyopathy, and discriminated from the normal condition. The LV shapes are modeled using shape histograms generated by plotting the frequency of normalized radii lengths drawn from the centroid to the periphery, against a specific number of bins. A 3-layer neural network activated by a log-sigmoid function is used to classify the shape histograms into one of the three classes. Experimentations on a dataset of 240 images show recognition accuracies of the order of 80%.

  17. Robust boundary detection and tracking of left ventricles on ultrasound images using active shape model and ant colony optimization.

    PubMed

    Zhang, Yaonan; Gao, Yuan; Jiao, Jinling; Li, Xian; Li, Sai; Yang, Jun

    2014-01-01

    Information regarding the motion, strain and synchronization are important for cardiac diagnosis and therapy. Extraction of such information from ultrasound images remains an open problem till today. In this paper, a novel method is proposed to extract the boundaries of left ventricles and track these boundaries in ultrasound image sequences. The initial detection of boundaries was performed by an active shape model scheme. Subsequent refinement of the boundaries was done by using local variance information of the images. The main objective of this paper is the formulation of a new boundary tracking algorithm using ant colony optimization technique. The experiments conducted on the simulated image sequences and the real cardiac ultrasound image sequences shows a positive and promising result. PMID:25226995

  18. Automated Classification of Disease Patterns from Echo-cardiography Images Based on Shape Features of the Left Ventricle

    SciTech Connect

    Das, Shaoli; Parekh, Ranjan

    2010-10-26

    Computer assisted diagnosis using analysis of medical images is an area of active research in health informatics. This paper proposes a technique for indication of heart diseases by using information related to shapes of the left ventricle (LV). LV boundaries are tracked from echo-cardiography images taken from LV short axis view, corresponding to two disease conditions viz. dilated cardiomyopathy and hypertrophic cardiomyopathy, and discriminated from the normal condition. The LV shapes are modeled using shape histograms generated by plotting the frequency of normalized radii lengths drawn from the centroid to the periphery, against a specific number of bins. A 3-layer neural network activated by a log-sigmoid function is used to classify the shape histograms into one of the three classes. Experimentations on a dataset of 240 images show recognition accuracies of the order of 80%.

  19. [Evaluation of systolic and diastolic function of the left ventricle in children with acute lymphoblastic leukaemia before treatment].

    PubMed

    Jackowska, Teresa; Pleskot, Marek; Gołabek, Małgorzata; Rokicka-Milewska, Roma; Wróblewska-Kałuzewska, Maria; Wypych, Agnieszka; Matysiak, Michał; Klus, Kinga; Juraszewska, Ewa; Balwierz, Walentyna; Wójcik, Beata; Sadurska, Elzbieta; Kowalczyk, Jerzy; Stencel, Dariusz; Siwinska, Aldona; Wachowiak, Jacek; Szmyd, Krzysztof; Kukawczyńska, Ewa; Chybicka, Alicja; Płoszyńska, Anna; Aleszewicz-Baranowska, Janina; Balcerska, Anna; Ostański, Mariusz; Pobudejska, Agnieszka; Sońta-Jakimczyk, Danuta; Krenke, Katarzyna; Madry, Wojtek; Syczewska, Małgorzata; Rudziński, Andrzej

    2004-01-01

    Between 1995 and 2001 echo-cardiography was performed in 244 children (128 boys, 116 girls) with acute lymphoblastic leukaemia (ALL) before the beginning of therapy with anthracyclines (medium 5.4 days after the diagnosis). The mean age at diagnosis was 5.4 years (range 9 months to 17.7 years). 189 children (97 boys and 92 girls) were included into the standard and medium risk groups and 55 (31 boys and 24 girls) into the high risk group. 29% of ALL children had disturbances in ECG. Changes in the thickness of the intraventricular septum (%IVSTh) and left ventricular posterior wall (%LVPWTh) were statistically lower, especially in children under 7 years of age. Some children showed lowering of shortening fraction (%FS - 8.6%), ejection fraction (%EF - 10.2%) and corrected velocity of fibber-shortening (Vcfc - 25.8%). Children with decreased shortening fraction (%FS) had left ventricular posterior wall thickness (%LVPWTh) impairment. Changes in diastolic function indicate impaired relaxation and compliance of the left ventricle. Decreased peak early filling velocity (E) was found. There were also longer deceleration time (EDecT) and decreased deceleration from peak E velocity (E/Dec) and longer isovolumetric relaxation time in children in standard and medium risk groups. Shorter acceleration time (EAccT) was seen in the high risk group. Evaluation of cardiac function before anthracycline chemotherapy will allow to select patients with pre-existing cardiac impairment for whom cardioprotective treatment is absolutely necessary. PMID:15686051

  20. Will Finite Elements Replace Structural Mechanics?

    NASA Astrophysics Data System (ADS)

    Ojalvo, I. U.

    1984-01-01

    This paper presents a personal view regarding the need for a continued interest and activity in structural methods in general, while viewing finite elements and the computer as simply two specific tools for assisting in this endeavor. An attempt is made to provide some insight as to why finite element methods seem to have "won the war," and to give examples of their more (and less) intelligent use. Items addressed include a highlight of unnecessary limitations of many existing standard finite element codes and where it is felt that further development work is needed.

  1. The finite element method in thermomechanics

    SciTech Connect

    Hsu, T.

    1986-01-01

    Thermal stress analysis is critical in the design and operation of energy-efficient power plant components and engines as well as in nuclear and aerospace systems. The Finite Element Method in Thermomechanics attempts to embrace a wide range of topics in the nonlinear thermomechanical analysis. The book covers the basic principles of the finite element method: the formulations for the base thermomechanical analysis, including thermoelastic-plastic-creep stress analysis; the use of Fourier series for nonaxisymmetric loadings, and stress waves in solids in thermal environments; and the base finite element code called TEPSAC.

  2. Myocardial regeneration after implantation of porcine small intestinal submucosa in the left ventricle

    PubMed Central

    Ramos, Cassiana Maria Garcez; Francisco, Julio César; Olandoski, Marcia; de Carvalho, Katherine Athayde Teixeira; Cunha, Ricardo; Erbano, Bruna Olandoski; Jorge, Lianna Ferrari; Baena, Cristina Pellegrino; do Amaral, Vivian Ferreira; Noronha, Lucia; de Macedo, Rafael Michel; Faria-Neto, José Rocha; Guarita-Souza, Luiz César

    2014-01-01

    Introduction Most cardiomyocytes do not regenerate after myocardial infarction. Porcine small intestinal submucosa has been shown to be effective in tissue repair. Objective To evaluate myocardial tissue regeneration and functional effects of SIS implantation in pigs after left ventriculotomy. Methods Fifteen pigs were assigned to two groups: porcine small intestinal submucosa (SIS) (N=10) and control (N=5). The SIS group underwent a mini sternotomy, left ventriculotomy and placement of a SIS patch. The control group underwent a sham procedure. Echocardiography was performed before and 60 days after the surgical procedure. Histological analysis was performed with hematoxylin-eosin stain and markers for actin 1A4, anti sarcomeric actin, connexin43 and factor VIII. Results Weight gain was similar in both groups. Echocardiography analysis revealed no difference between groups regarding end diastolic and systolic diameters and left ventricular ejection fraction, both pre (P=0.118, P=0.313, P=0.944) and post procedure (P=0.333, P=0.522, P=0.628). Both groups showed an increase in end diastolic (P<0,001 for both) and systolic diameter 60 days after surgery (P=0.005, SIS group and P=0.004, control group). New cardiomyocytes, blood vessels and inflammatory reactions were histologically identified in the SIS group. Conclusion SIS implantation in pigs after left ventriculotomy was associated with angiomuscular regeneration and no damage in cardiac function. PMID:25140470

  3. A survey of mixed finite element methods

    NASA Technical Reports Server (NTRS)

    Brezzi, F.

    1987-01-01

    This paper is an introduction to and an overview of mixed finite element methods. It discusses the mixed formulation of certain basic problems in elasticity and hydrodynamics. It also discusses special techniques for solving the discrete problem.

  4. Noncomplicated Excision of a Mobile Pedunculated Septal Hemangioma of the Left Ventricle

    PubMed Central

    Mazen, Mahmoud; Abdelgawad, Ahmed; El-Shemy, Ahmed; Ramadan, Mona; Al-Batrek, Hani; Mahdi, Ousama; Ramadan, Mahmoud M.

    2016-01-01

    Patient: Female, 27 Final Diagnosis: LV hemangioma Symptoms: Palpitation • dyspnea • fatigue Medication: — Clinical Procedure: Posterior atriotomy Specialty: Cardiology Objective: Rare disease Background: Cardiac tumors are quite rare, and differential diagnosis of them is challenging. Case Report: A young lady with a history of palpitations, dyspnea, and fatigue was proven by transthoracic echocardiography and cardiac magnetic resonance imaging to have a mobile left ventricular mass with rounded contour attached to the mid-part of the interventricular septum. The mass was approached via a posterior inter-atrial approach to avoid left ventriculotomy and provide adequate exposure to completely excise the tumor and control its pedicle with minimal cardiac trauma. Histological examination of the mass was diagnostic of capillary and sinusoidal hemangioma. Conclusions: Complete excision of cardiac hemangioma is recommended once it is diagnosed, for histopathologic diagnosis and because of the possibility of serious complications. PMID:27384944

  5. Noncomplicated Excision of a Mobile Pedunculated Septal Hemangioma of the Left Ventricle.

    PubMed

    Mazen, Mahmoud; Abdelgawad, Ahmed; El-Shemy, Ahmed; Ramadan, Mona; Al-Batrek, Hani; Mahdi, Ousama; Ramadan, Mahmoud M

    2016-01-01

    BACKGROUND Cardiac tumors are quite rare, and differential diagnosis of them is challenging. CASE REPORT A young lady with a history of palpitations, dyspnea, and fatigue was proven by transthoracic echocardiography and cardiac magnetic resonance imaging to have a mobile left ventricular mass with rounded contour attached to the mid-part of the interventricular septum. The mass was approached via a posterior inter-atrial approach to avoid left ventriculotomy and provide adequate exposure to completely excise the tumor and control its pedicle with minimal cardiac trauma. Histological examination of the mass was diagnostic of capillary and sinusoidal hemangioma. CONCLUSIONS Complete excision of cardiac hemangioma is recommended once it is diagnosed, for histopathologic diagnosis and because of the possibility of serious complications. PMID:27384944

  6. Finite element modeling of the human pelvis

    SciTech Connect

    Carlson, B.

    1995-11-01

    A finite element model of the human pelvis was created using a commercial wire frame image as a template. To test the final mesh, the model`s mechanical behavior was analyzed through finite element analysis and the results were displayed graphically as stress concentrations. In the future, this grid of the pelvis will be integrated with a full leg model and used in side-impact car collision simulations.

  7. Finite-Element Modeling For Structural Analysis

    NASA Technical Reports Server (NTRS)

    Min, J. B.; Androlake, S. G.

    1995-01-01

    Report presents study of finite-element mathematical modeling as used in analyzing stresses and strains at joints between thin, shell-like components (e.g., ducts) and thicker components (e.g., flanges or engine blocks). First approach uses global/local model to evaluate system. Provides correct total response and correct representation of stresses away from any discontinuities. Second approach involves development of special transition finite elements to model transitions between shells and thicker structural components.

  8. Correlation-based discrimination between cardiac tissue and blood for segmentation of the left ventricle in 3-D echocardiographic images.

    PubMed

    Saris, Anne E C M; Nillesen, Maartje M; Lopata, Richard G P; de Korte, Chris L

    2014-03-01

    For automated segmentation of 3-D echocardiographic images, incorporation of temporal information may be helpful. In this study, optimal settings for calculation of temporal cross-correlations between subsequent time frames were determined, to obtain the maximum cross-correlation (MCC) values that provided the best contrast between blood and cardiac tissue over the entire cardiac cycle. Both contrast and boundary gradient quality measures were assessed to optimize MCC values with respect to signal choice (radiofrequency or envelope data) and axial window size. Optimal MCC values were incorporated into a deformable model to automatically segment the left ventricular cavity. MCC values were tested against, and combined with, filtered, demodulated radiofrequency data. Results reveal that using envelope data in combination with a relatively small axial window (0.7-1.25 mm) at fine scale results in optimal contrast and boundary gradient between the two tissues over the entire cardiac cycle. Preliminary segmentation results indicate that incorporation of MCC values has additional value for automated segmentation of the left ventricle. PMID:24412178

  9. A laboratory investigation of the flow in the left ventricle of a human heart with prosthetic, tilting-disk valves

    NASA Astrophysics Data System (ADS)

    Cenedese, A.; del Prete, Z.; Miozzi, M.; Querzoli, G.

    2005-08-01

    The understanding of the phenomena involved in ventricular flow is becoming more and more important because of two main reasons: the continuous improvements in the field of diagnostic techniques and the increasing popularity of prosthetic devices. On one hand, more accurate investigation techniques gives the chance to better diagnose diseases before they become dangerous to the health of the patient. On the other hand, the diffusion of prosthetic devices requires very detailed assessment of the modifications that they introduce in the functioning of the heart. The present work is focussed on the experimental investigation of the flow in the left ventricle of the human heart with the presence of a tilting-disk valve in the mitral position, as this kind of valve is known to change deeply the structure of such a flow. A laboratory model has been built up, which consists of a cavity able to change its volume, representing the ventricle, on which two prosthetic valves are mounted. The facility is designed to be able to reproduce any arbitrarily assigned law of variation of the ventricular volume with time. In the present experiment, a physiologically shaped curve has been used. Velocity was measured using a feature-tracking (FT) algorithm; as a consequence, the particle trajectories are known. The flow has been studied by changing both the beat rate and the stroke volume. The flow was studied both kinematically, examining velocity and vorticity fields, and dynamically, evaluating turbulent and viscous shear stresses, and inertial forces exerted on fluid elements. The analysis of the results allows the identification of the main features of the ventricular flow, generated by a mitral, tilting-disk valve, during the whole cardiac cycle and its dependence on the frequency and the stroke volume.

  10. Left atrioventricular remodeling in the assessment of the left ventricle diastolic function in patients with heart failure: a review of the currently studied echocardiographic variables

    PubMed Central

    Danzmann, Luiz C; Bodanese, Luiz Carlos; Köhler, Ilmar; Torres, Marco R

    2008-01-01

    Multiparametric echocardiographic imaging of the failing heart is now increasingly used and useful in decision making in heart failure. The reasons for this, relies on the need of different strategies of handling these patients, as differentiation of systolic or diastolic dysfunction, as well as on the gamma of approaches available, such as percutaneous and surgical revascularization, devices implantations, and valvular regurgitations and stenosis corrections. Congestive heart failure in patients with normal left ventricular diameters or preserved left ventricular ejection fraction had been pointed out recently as present in a proportion so high as 40 to 50 percent of cases of heart failure, mainly due to the epidemics in well developed countries, as is the problem of not well controlled metabolic states (such as obesity and diabetes), but also due to the real word in developing countries, as is the case of hypertension epidemics and its lack of adequate control. As a matter of public utility, the guidelines in the diagnosis and treatment of such patients will have to be cheap, available, easily reproducible, and ideally will furnish answers for the clinician questions not in a binary "black or white" manner, but with graduations, so if possible it has to be quantitative. The present paper aim to focus on the current clinical applications of tissue Doppler and of left atrial function and remodeling, and its pathophysiologic relationship with the left ventricle, as will be cleared in the documented review of echocardiography that follows, considering that the need of universal data on the syndrome of the failing heart does not mean, unfortunately, that all patients and clinicians in developing countries have at their own health facilities the same imaging tools, since they are, as a general rule, expensive. PMID:19014611

  11. Echocardiographic diastolic abnormalities of the left ventricle in inflammatory joint disease.

    PubMed Central

    Rowe, I F; Gibson, D G; Keat, A C; Brewerton, D A

    1991-01-01

    Echocardiographic early diastolic abnormalities have been shown recently in 50% of men with ankylosing spondylitis. Similar techniques were used to investigate subjects with rheumatoid arthritis and psoriatic arthritis with or without spondylitis. These subjects had no clinical, radiographic, or electrocardiographic evidence of cardiac or respiratory disease. Echocardiographic abnormalities seen resembled those of ankylosing spondylitis in that the interval between minimum left ventricular dimension and mitral valve opening was prolonged in 12 of 22 subjects with rheumatoid arthritis and in seven of 11 subjects with psoriatic arthritis. Isovolumic relaxation time was significantly prolonged in four subjects with rheumatoid arthritis and one with psoriatic arthritis. Unlike ankylosing spondylitis, however, there was consistent reduction in peak rate of left ventricular dimension increase in subjects with rheumatoid arthritis and psoriatic arthritis. In addition, the dimension increase during atrial systole was greater than normal in nine subjects with rheumatoid arthritis and two with psoriatic arthritis. The most likely cause of these abnormalities is increased connective tissue deposition in the myocardium. Images PMID:2029204

  12. Aortic pressure reduction redistributes transmural blood flow in dog left ventricle

    SciTech Connect

    Smolich, J.J.; Weissberg, P.L.; Broughton, A.; Korner, P.I. )

    1988-02-01

    The authors studied the effect of graded aortic blood pressure reduction on left ventricular (LV) blood flow in anesthetized, autonomically blocked, open-chest dogs at constant heart rate and mean left atrial pressure. Aortic diastolic pressure (ADP) was lowered from rest to 90, 75, and 60 mmHg with an arteriovenous fistula. Global and regional LV blood flow was measured with radioactive microspheres. Mean LV blood flow fell stepwise from 145 ml {center dot} min{sup {minus}1} {center dot} 100 g{sup {minus}1} at rest to 116 ml {center dot} min{sup {minus}1} {center dot} 100 g{sup {minus}1} at ADP of 60 mmHg, whereas the endocardial-to-epicardial flow ratio decreased from 1.20 to 084. The transmural redistribution of LV blood flow was not accompanied by increases in LV oxygen extraction, depression of LV contractility, LV dilatation or LV electrical dysfunction and also occurred in the presence of considerable coronary vasodilator flow reserve. Electrical evidence of subendocardial ischemia appeared at ADP of 32 mmHg and an endocardial-to-epicardial flow ratio of 0.41 in a subgroup of animals. They conclude that the redistribution of LV flow during moderate aortic pressure reduction was an appropriate physiological adjustment to uneven transmural alterations in regional LV wall stress and that it preceded a more pronounced redistribution evident with myocardial ischemia.

  13. The Spatial Distribution of Actin and Mechanical Cycle of Myosin Are Different in Right and Left Ventricles of Healthy Mouse Hearts

    PubMed Central

    2014-01-01

    The contraction of the right ventricle (RV) expels blood into the pulmonary circulation, and the contraction of the left ventricle (LV) pumps blood into the systemic circulation through the aorta. The respective afterloads imposed on the LV and RV by aortic and pulmonary artery pressures create very different mechanical requirements for the two ventricles. Indeed, differences have been observed in the contractile performance between left and right ventricular myocytes in dilated cardiomyopathy, in congestive heart failure, and in energy usage and speed of contraction at light loads in healthy hearts. In spite of these functional differences, it is commonly believed that the right and left ventricular muscles are identical because there were no differences in stress development, twitch duration, work performance, or power among the RV and LV in dogs. This report shows that on a mesoscopic scale [when only a few molecules are studied (here three to six molecules of actin) in ex vivo ventricular myofibrils], the two ventricles in rigor differ in the degree of orientational disorder of actin within in filaments and during contraction in the kinetics of the cross-bridge cycle. PMID:25488019

  14. Particle tracking velocimetry using echocardiographic data resolves flow in the left ventricle

    NASA Astrophysics Data System (ADS)

    Sampath, Kaushik; Abd, Thura T.; George, Richard T.; Katz, Joseph

    2015-11-01

    Two dimensional contrast echocardiography was performed on patients with a history of left ventricular (LV) thrombus. The 636 x 434 pixels electrocardiograms were recorded using a GE Vivid 9E system with (M5S-D and 4V-D) probes in a 2-D mode at a magnification of 0.3 mm/pix. The concentration of 2-4.5 micron seed bubbles was adjusted to obtain individually discernable traces, and a data acquisition rate of 60-90 fps kept the inter-frame displacements suitable for matching traces, and calculating vectors, but yet low enough to allow a scanning depth and width of upto 13 cm and 60 degrees respectively. Particle tracking velocimetry (PTV) guided by initial particle image velocimetry (PIV) was used to obtain the velocity distributions inside the LV with vector spacing of 3-5 mm. The data quality was greatly enhanced by implementing an iterative particle specific enhancement and tracking algorithm. Data covering 20 heart beats facilitated phase averaging. The results elucidated blood flow in the intra-ventricular septal region, lateral wall region, the apex of the LV and the mitral valve region.

  15. A semi-automatic method for left ventricle volume estimate: an in vivo validation study

    NASA Technical Reports Server (NTRS)

    Corsi, C.; Lamberti, C.; Sarti, A.; Saracino, G.; Shiota, T.; Thomas, J. D.

    2001-01-01

    This study aims to the validation of the left ventricular (LV) volume estimates obtained by processing volumetric data utilizing a segmentation model based on level set technique. The validation has been performed by comparing real-time volumetric echo data (RT3DE) and magnetic resonance (MRI) data. A validation protocol has been defined. The validation protocol was applied to twenty-four estimates (range 61-467 ml) obtained from normal and pathologic subjects, which underwent both RT3DE and MRI. A statistical analysis was performed on each estimate and on clinical parameters as stroke volume (SV) and ejection fraction (EF). Assuming MRI estimates (x) as a reference, an excellent correlation was found with volume measured by utilizing the segmentation procedure (y) (y=0.89x + 13.78, r=0.98). The mean error on SV was 8 ml and the mean error on EF was 2%. This study demonstrated that the segmentation technique is reliably applicable on human hearts in clinical practice.

  16. Effect of Trabeculae on the Hemodynamics of an Embryonic Left Ventricle

    NASA Astrophysics Data System (ADS)

    Vedula, Vijay; Lee, Juhyun; Hsiai, Tzung; Marsden, Alison

    2015-11-01

    The left ventricular (LV) endocardium is not smooth, but has ``trabeculae'' protruding into the LV cavity. Recent studies have indicated that trabeculae significantly influence LV hemodynamics by enhancing the diastolic penetration depth of inflow and facilitating a better apical systolic washout. However, it remains unclear how the role of hemodynamics modulates the initiation of trabeculae during cardiac morphogenesis. While such an assessment of mammalian heart models is hampered by the prolonged duration of cardiac development and complexity of surrounding internal organs, embryonic zebrafish is a genetically tractable model for investigating cardiac morphogenesis. We employ a novel light-sheet fluorescent microscopy to extract 4D LV models of zebrafish and develop an ALE-based moving domain CFD solver to perform flow simulations and extract quantitative data related to flow velocities and pressure gradients. We will compare near-wall flow dynamics between the wild type zebrafish (with trabeculae) and the cloche mutant lines that fail to develop trabeculae, to provide new insights into the flow-induced mechano-transduction relevant to the initiation of trabeculae during cardiac morphogenesis. This research is supported by NIH 1R01HL121754-01 grant and Burroughs Wellcome Fund Career Award. Computational resources are provided through the NSF XSEDE grant TG-CTS130034. The light-sheet imaging and zebrafish model are supported by NIH 1R01HL129727.

  17. The relationship between left ventricle myocardial performance index of healthy women and geographical factors

    NASA Astrophysics Data System (ADS)

    Han, Xiao; Ge, Miao; Dong, Jie; Wang, Zixuan; He, Jinwei; Yang, Rongrong

    2015-11-01

    The study focused on the relationship between geographical factors and left ventricular myocardial performance index (MPI)reference value, analyed the different distribution of MPI, and then provided a scientific basis for clinical examination. This study collected MPI reference values of 2545 healthy women from 91 cities in China, used the Moran's index to determin the spatial relationship, selected 25 geographical factors, examined the significance between MPI and geographical factors by correlation analysis, through the significance test, and extracted seven significant factors to build the artificial neural network (ANN) model and principal component analysis (PCA) model. Through calculating the relative error, the ANN model was chosen as the better model to predict the values. By normality test for the predicted values, the geographical distribution was made by disjunctive kriging interpolation. The predicted values decrease from north to south. If geographical factors are obtained in one location, the MPI of healthy women in this area can be predicted by the ANN model. Synthesizing the influence of physiological and geographical could be more scientific to formulate the MPI reference value.

  18. Left ventricle myocardial border detection in three-dimensional intracardiac ultrasound images

    NASA Astrophysics Data System (ADS)

    Liang, Weidong; Kanani, Prapti; Allan, John; Kerber, Richard; McKay, Charles R.; Sonka, Milan

    1997-05-01

    We have previously reported an automated approach to detection of endocardial and epicardial borders in individual intracardiac ultrasound (ICUS) images. Here, we report the method's extension to 3D ICUS image data sets. Our method is based on fully automated detection of epicardial and endocardial borders inside a single interactively identified region of interest. BOrder detection is based on an optimal graph-searching approach that utilizes a priori knowledge about left ventricular (LV) anatomy and ultrasound imaging physics. Eight cadaveric pig hearts were used for validation. Two ICUS sequences were obtained from each heart, with a 10 MHz CVIS 10F catheter positioned in the LV across (1) the aortic valve and (2) the mitral valve. Performance of the 3D automated border detection method was assessed by comparing the observer- defined and computer-determined quantitative indices of LV volume and by border positioning errors. The 3D reconstruction of the lV was performed from the sequences of the detected epicardial and endocardial borders using shape- based interpolation and surface rendering.

  19. Relationship between cardioscopic images and histological changes in the left ventricle of patients with idiopathic myocarditis†

    PubMed Central

    Uchida, Yasumi; Uchida, Yasuto; Sakurai, Takeshi; Kanai, Masahito; Shirai, Seiichiro; Nakagawa, Osamu; Hiruta, Nobuyuki

    2011-01-01

    Aims Endomyocardial biopsy is essential for definite diagnosis of idiopathic myocarditis. However, since endomyocardial biopsy is guided by fluoroscopy, whether or not the diseased myocardium is biopsied depends on chance, and this may lead to misdiagnosis. If the endocardial surface represents changes indicative of stages of myocarditis, staging of myocarditis and targeted cardioscope-guided biopsy could be used for accurate histological diagnosis. Methods and results The relationship between left ventricular endocardial surface colour observed by cardioscopy and biopsy findings were examined in 78 patients with suspected idiopathic myocarditis. Of these, 59 patients were diagnosed histologically as idiopathic myocarditis. Endocardial colour was classified into red, milky white, purple, yellowish brown, or white. Biopsied specimens with red and milky white wall segments exhibited histological changes compatible with acute myocarditis; purple segments, active chronic myocarditis; and yellowish brown and white segments, inactive chronic myocarditis. The sensitivity, specificity, and predictive value of red and milky white colours for detecting acute myocarditis were 100, 100, and 100%, respectively; of purple for detecting active chronic myocarditis were 83, 92, and 78%, respectively; and yellowish brown and white for detecting inactive chronic myocarditis were 82, 74, and 53, respectively. Conclusion Red and milky white endocardial surface colours predicted histological acute myocarditis, and purple predicted active chronic myocarditis. However, yellowish brown and white colours did not predict inactive chronic myocarditis. PMID:21257727

  20. [Contraction disorders of the left ventricle in ischemic heart disease. Studies using atrial stimulation].

    PubMed

    Schwarz, F; Thormann, J; Zimmermann, H; Winkler, B

    1975-01-25

    Sixty-one patients with suspected ischemic heart disease (IHD) have been investigated by atrial stimulation (AST). Group A patients had normal coronarograms and served as controls. Group B patients had pathological conronarograms (at least 50% stenosis in one of the 3 vessels) and normal ventriculograms. Group C patients had pathological coronarograms and ventricular aneurysms. During AST, group C patients exhibited lower dp/dt max and dp/dt min as well as higher left ventricular end-diastolic pressure (LVEDP) and/or mean pulmonary artery pressure (MPAP) than groups A and B. Group B differed from group A only by increased MPAP during AST. When compared to controls, contractility in group C was reduced even at rest. AST offers an excellent means of diagnosing IHD if heart rates of 140/min and above are used. An abnormal increase in MPAP serves as the simplest parameter for IHD. Elevated MPAP at rest prompts suspicion of ventricular aneurysm. It is possible to deduce a quanitative estimate of contracitility by correlating dp/dt max to LVEDP. A hyperbolic relation results. PMID:1124378

  1. Cardiac dysfunction and orthostatic intolerance in patients with myalgic encephalomyelitis and a small left ventricle.

    PubMed

    Miwa, Kunihisa

    2015-07-01

    The etiology of chronic fatigue syndrome (CFS) is unknown. Myalgic encephalomyelitis (ME) has been recently postulated to be the cause of CFS. Orthostatic intolerance (OI) has been known as an important symptom in predicting quality of life in CFS patients. Cardiac function may be impaired in patients with ME. The presence or absence of OI was determined both symptomatically and by using a 10-min stand-up test in 40 ME patients. Left ventricular (LV) dimensions and function were determined echocardiographically in the ME patients compared to 40 control subjects. OI was noted in 35 (97%) of the 36 ME patients who could stand up quickly. The mean values for the cardiothoracic ratio, systemic systolic and diastolic pressures, LV end-diastolic diameter (EDD), LV end-systolic diameter, stroke volume index, cardiac index and LV mass index were all significantly smaller in the ME group than in the controls. Both a small LVEDD (<40 mm, 45 vs. 3%) and a low cardiac index (<2 l/ min/mm2, 53 vs. 8%) were significantly more common in the ME group than in the controls. Both heart rate and LV ejection fraction were similar between the groups. In conclusion, a small LV size with a low cardiac output was common in ME patients, in whom OI was extremely common. Cardiac dysfunction with a small heart appears to be related to the symptoms of ME. PMID:24736946

  2. The Clinical Benefits of Adding a Third Dimension to Assess the Left Ventricle with Echocardiography

    PubMed Central

    Badano, Luigi P.

    2014-01-01

    Three-dimensional echocardiography is a novel imaging technique based on acquisition and display of volumetric data sets in the beating heart. This permits a comprehensive evaluation of left ventricular (LV) anatomy and function from a single acquisition and expands the diagnostic possibilities of noninvasive cardiology. It provides the possibility of quantitating geometry and function of LV without preestablished assumptions regarding cardiac chamber shape and allows an echocardiographic assessment of the LV that is less operator-dependent and therefore more reproducible. Further developments and improvements for widespread routine applications include higher spatial and temporal resolution to improve image quality, faster acquisition, processing and reconstruction, and fully automated quantitative analysis. At present, three-dimensional echocardiography complements routine 2DE in clinical practice, overcoming some of its limitations and offering additional valuable information that has led to recommending its use for routine assessment of the LV of patients in whom information about LV size and function is critical for their clinical management. PMID:24959374

  3. Dose impaired relaxation of left ventricle affect early outcomes in CABG patients?

    PubMed

    Bagheri, Jamshid; Rezakhanloo, Fereshteh

    2010-01-01

    Although systolic dysfunction is revealed as a prognostic factor in cardiac surgery, the role of diastolic dysfunction as a predictive factor is less evaluated. In this retrospective study from 872 patients that underwent isolated coronary artery bypass graft (Jan 2008-Feb 2009), 388 patients had normal left ventricular ejection fraction (>50%). These are divided in two groups, Group 1: 361 patients without diastolic dysfunction (impaired relaxation) and Group 2: 27 patients with diastolic dysfunction (impaired relaxation). Mean age in group 1 was 57.72 year and in group 2 was 61.16 year (P = 0.07). Risk factors such as diabetes mellitus, hypertention and dyslipidemia were similar. Although overall complication rate was higher in group 2 (11.1% vs. 2.8% P value 0.05), but when each complication was studied individually no significant statistical difference was found. Also no significant statistical difference was found in mortality (2.2% in group 1 vs 7.4% in group 2 P = 0.1). In conclusion, from clinical standpoint diastolic dysfunction can be an important factor in assessing surgical outcome in patients whom underwent coronary artery bypass grafting. PMID:21137652

  4. Hyperglycemia has a greater impact on left ventricle function in South Asians than in Europeans

    PubMed Central

    Park, Chloe M; Tillin, Therese; March, Katherine; Ghosh, Arjun K; Jones, Siana; Wright, Andrew; Heasman, John; Francis, Darrel; Sattar, Naveed; Mayet, Jamil; Chaturvedi, Nish; Hughes, Alun D

    2016-01-01

    Objective Diabetes is associated with left ventricular diastolic and systolic dysfunction. South Asians may be at particular risk of developing LV dysfunction due to a high prevalence of diabetes. We investigated the role of diabetes and hyperglycaemia in LV dysfunction in a community-based cohort of older South Asians and White Europeans. Research Design and Methods Conventional and Doppler echocardiography was performed in 999 participants (542 Europeans, 457 South Asians aged 58-86 years) in a population-based study. Anthropometry, fasting bloods, coronary artery calcification scoring, blood pressure and renal function were measured. Results Diabetes, and hyperglycaemia across the spectrum of HbA1c had a greater adverse effect on LV function in South Asians than Europeans (NT-proBNP beta±SE 0.09±0.04, p=0.01 versus -0.04±0.05, p=0.4, p for HbA1c/ethnicity interaction 0.02), diastolic function (E/e’ 0.69±0.12, p<0.0001 versus 0.09±0.2, p=0.6, p interaction 0.005, and systolic function (s’ -0.11±0.06, p=0.04 versus 0.14±0.09, p=0.1, p interaction 0.2). Multivariable adjustment for hypertension, microvascular disease, LV mass, coronary disease and dyslipidaemia only partially accounted for the ethnic differences. Adverse LV function in diabetic South Asians could not be accounted for by poorer glycaemic control or longer diabetes duration. Conclusions Diabetes and hyperglycaemia have a greater adverse effect on LV function in South Asians than Europeans incompletely explained by adverse risk factors. South Asians may require earlier, and more aggressive treatment of their cardiometabolic risk factors to reduce risks of LV dysfunction. PMID:24241789

  5. Myofiber angle distributions in the ovine left ventricle do not conform to computationally optimized predictions

    PubMed Central

    Ennis, Daniel B.; Nguyen, Tom C.; Riboh, Jonathan C.; Wigström, Lars; Harrington, Katherine B.; Daughters, George T.; Ingels, Neil B.; Miller, D. Craig

    2008-01-01

    Recent computational models of optimized left ventricular (LV) myofiber geometry that minimize the spatial variance in sarcomere length, stress, and ATP consumption have predicted that a midwall myofiber angle of 20° and transmural myofiber angle gradient of 140° from epicardium to endocardium is a functionally optimal LV myofiber geometry. In order to test the extent to which actual fiber angle distributions conform to this prediction, we measured local myofiber angles at an average of nine transmural depths in each of 32 sites (4 short-axis levels, 8 circumferentially distributed blocks in each level) in five normal ovine LVs. We found: 1) a mean midwall myofiber angle of −7° (SD 9), but with spatial heterogeneity (averaging 0° in the posterolateral and anterolateral wall near the papillary muscles, and −9° in all other regions); and 2) an average transmural gradient of 93° (SD 21), but with spatial heterogeneity (averaging a low of 51° in the basal posterior sector and a high of 130° in the mid-equatorial anterolateral sector). We conclude that midwall myofiber angles and transmural myofiber angle gradients in the ovine heart are regionally non-uniform and differ significantly from the predictions of present-day computationally optimized LV myofiber models. Myofiber geometry in the ovine heart may differ from other species, but model assumptions also underlie the discrepancy between experimental and computational results. To test of the predictive capability of the current computational model would we propose using an ovine specific LV geometry and comparing the computed myofiber orientations to those we report herein. PMID:18805536

  6. Three-dimensional active shape model matching for left ventricle segmentation in cardiac CT

    NASA Astrophysics Data System (ADS)

    van Assen, Hans C.; van der Geest, Rob J.; Danilouchkine, Mikhail G.; Lamb, Hildo J.; Reiber, Johan H. C.; Lelieveldt, Boudewijn P. F.

    2003-05-01

    Manual quantitative analysis of cardiac left ventricular function using multi-slice CT is labor intensive because of the large datasets. We present an automatic, robust and intrinsically three-dimensional segmentation method for cardiac CT images, based on 3D Active Shape Models (ASMs). ASMs describe shape and shape variations over a population as a mean shape and a number of eigenvariations, which can be extracted by e.g. Principal Component Analysis (PCA). During the iterative ASM matching process, the shape deformation is restricted within statistically plausible constraints (+/-3σ). Our approach has two novel aspects: the 3D-ASM application to volume data of arbitrary planar orientation, and the application to image data from another modality than which was used to train the model, without the necessity of retraining it. The 3D-ASM was trained on MR data and quantitatively evaluated on 17 multi-slice cardiac CT data sets, with respect to calculated LV volume (blood pool plus myocardium) and endocardial volume. In all cases, model matching was convergent and final results showed a good model performance. Bland-Altman analysis however, showed that bloodpool volume was slightly underestimated and LV volume was slightly overestimated by the model. Nevertheless, these errors remain within clinically acceptable margins. Based on this evaluation, we conclude that our 3D-ASM combines robustness with clinically acceptable accuracy. Without retraining for cardiac CT, we could adapt a model trained on cardiac MR data sets for application in cardiac CT volumes, demonstrating the flexibility and feasibility of our matching approach. Causes for the systematic errors are edge detection, model constraints, or image data reconstruction. For all these categories, solutions are discussed.

  7. Hyperglycemia has a greater impact on left ventricle function in South Asians than in Europeans.

    PubMed

    Park, Chloe M; Tillin, Therese; March, Katherine; Ghosh, Arjun K; Jones, Siana; Wright, Andrew; Heasman, John; Francis, Darrel; Sattar, Naveed; Mayet, Jamil; Chaturvedi, Nish; Hughes, Alun D

    2014-04-01

    OBJECTIVE Diabetes is associated with left ventricular (LV) diastolic and systolic dysfunction. South Asians may be at particular risk of developing LV dysfunction owing to a high prevalence of diabetes. We investigated the role of diabetes and hyperglycemia in LV dysfunction in a community-based cohort of older South Asians and white Europeans. RESEARCH DESIGN AND METHODS Conventional and Doppler echocardiography was performed in 999 participants (542 Europeans and 457 South Asians aged 58-86 years) in a population-based study. Anthropometry, fasting bloods, coronary artery calcification scoring, blood pressure, and renal function were measured. RESULTS Diabetes and hyperglycemia across the spectrum of HbA1c had a greater adverse effect on LV function in South Asians than Europeans (N-terminal-probrain natriuretic peptide β ± SE 0.09 ± 0.04, P = 0.01, vs. -0.04 ± 0.05, P = 0.4, P for HbA1c/ethnicity interaction 0.02), diastolic function (E/e' 0.69 ± 0.12, P < 0.0001, vs. 0.09 ± 0.2, P = 0.6, P for interaction 0.005), and systolic function (s' -0.11 ± 0.06, P = 0.04, vs. 0.14 ± 0.09, P = 0.1, P for interaction 0.2). Multivariable adjustment for hypertension, microvascular disease, LV mass, coronary disease, and dyslipidemia only partially accounted for the ethnic differences. Adverse LV function in diabetic South Asians could not be accounted for by poorer glycemic control or longer diabetes duration. CONCLUSIONS Diabetes and hyperglycemia have a greater adverse effect on LV function in South Asians than Europeans, incompletely explained by adverse risk factors. South Asians may require earlier and more aggressive treatment of their cardiometabolic risk factors to reduce risks of LV dysfunction. PMID:24241789

  8. Fast left ventricle tracking in CMR images using localized anatomical affine optical flow

    NASA Astrophysics Data System (ADS)

    Queirós, Sandro; Vilaça, João. L.; Morais, Pedro; Fonseca, Jaime C.; D'hooge, Jan; Barbosa, Daniel

    2015-03-01

    In daily cardiology practice, assessment of left ventricular (LV) global function using non-invasive imaging remains central for the diagnosis and follow-up of patients with cardiovascular diseases. Despite the different methodologies currently accessible for LV segmentation in cardiac magnetic resonance (CMR) images, a fast and complete LV delineation is still limitedly available for routine use. In this study, a localized anatomically constrained affine optical flow method is proposed for fast and automatic LV tracking throughout the full cardiac cycle in short-axis CMR images. Starting from an automatically delineated LV in the end-diastolic frame, the endocardial and epicardial boundaries are propagated by estimating the motion between adjacent cardiac phases using optical flow. In order to reduce the computational burden, the motion is only estimated in an anatomical region of interest around the tracked boundaries and subsequently integrated into a local affine motion model. Such localized estimation enables to capture complex motion patterns, while still being spatially consistent. The method was validated on 45 CMR datasets taken from the 2009 MICCAI LV segmentation challenge. The proposed approach proved to be robust and efficient, with an average distance error of 2.1 mm and a correlation with reference ejection fraction of 0.98 (1.9 +/- 4.5%). Moreover, it showed to be fast, taking 5 seconds for the tracking of a full 4D dataset (30 ms per image). Overall, a novel fast, robust and accurate LV tracking methodology was proposed, enabling accurate assessment of relevant global function cardiac indices, such as volumes and ejection fraction

  9. Fluid-structure interaction of an aortic heart valve prosthesis driven by an animated anatomic left ventricle

    NASA Astrophysics Data System (ADS)

    Le, Trung Bao; Sotiropoulos, Fotis

    2013-07-01

    We develop a novel large-scale kinematic model for animating the left ventricle (LV) wall and use this model to drive the fluid-structure interaction (FSI) between the ensuing blood flow and a mechanical heart valve prosthesis implanted in the aortic position of an anatomic LV/aorta configuration. The kinematic model is of lumped type and employs a cell-based, FitzHugh-Nagumo framework to simulate the motion of the LV wall in response to an excitation wavefront propagating along the heart wall. The emerging large-scale LV wall motion exhibits complex contractile mechanisms that include contraction (twist) and expansion (untwist). The kinematic model is shown to yield global LV motion parameters that are well within the physiologic range throughout the cardiac cycle. The FSI between the leaflets of the mechanical heart valve and the blood flow driven by the dynamic LV wall motion and mitral inflow is simulated using the curvilinear immersed boundary (CURVIB) method (Ge and Sotiropoulos, 2007; Borazjani et al., 2008) [1,2] implemented in conjunction with a domain decomposition approach. The computed results show that the simulated flow patterns are in good qualitative agreement with in vivo observations. The simulations also reveal complex kinematics of the valve leaflets, thus, underscoring the need for patient-specific simulations of heart valve prosthesis and other cardiac devices.

  10. Relationship between changes of chamber mechanical parameters and mean pressure-mean flow diagrams of the left ventricle.

    PubMed

    Negroni, J A; Lascano, E C; Pichel, R H

    1988-01-01

    A theoretical relationship between mean ventricular pressure (P) and mean ventricular outflow (Q) was developed based on a model of the left ventricle with elastic-resistive properties. Using a polynomial interpolation method, a fifth-order polynomial equation for the P-Q relationship was obtained. Its coefficients are functions of end-diastolic volume (VD), heart rate (HR), contractile state (CS), diastolic elastance (ED), asymmetry (S) of the elastance function E(t), and ventricular internal resistance factor (K). Effect of changes of these parameters indicated that normal and enhanced CS relations diverge toward the P axis but have a common intercept toward the Q axis. A similar effect was obtained with increased asymmetry of E(t). Changes in VD, HR and ED produced a parallel shift of the P-Q relation. The effect of K was negligible, however, which would reduce the description of the P-Q relationship to a third-order polynomial equation. A flow-dependent deactivation component was introduced, altering the asymmetry factor S, which decreases in a linear proportion to Q. This factor shifted the pump function graph downwards. We conclude that the theoretical description of the P-Q relation we present reproduces the experimental behavior of pump function diagrams reported in the literature (changes in VD, HR, and CS) and predicts the possible behavior due to other parameter changes. PMID:3400909

  11. Electrical Wave Propagation in an Anisotropic Model of the Left Ventricle Based on Analytical Description of Cardiac Architecture

    PubMed Central

    Pravdin, Sergey F.; Dierckx, Hans; Katsnelson, Leonid B.; Solovyova, Olga; Markhasin, Vladimir S.; Panfilov, Alexander V.

    2014-01-01

    We develop a numerical approach based on our recent analytical model of fiber structure in the left ventricle of the human heart. A special curvilinear coordinate system is proposed to analytically include realistic ventricular shape and myofiber directions. With this anatomical model, electrophysiological simulations can be performed on a rectangular coordinate grid. We apply our method to study the effect of fiber rotation and electrical anisotropy of cardiac tissue (i.e., the ratio of the conductivity coefficients along and across the myocardial fibers) on wave propagation using the ten Tusscher–Panfilov (2006) ionic model for human ventricular cells. We show that fiber rotation increases the speed of cardiac activation and attenuates the effects of anisotropy. Our results show that the fiber rotation in the heart is an important factor underlying cardiac excitation. We also study scroll wave dynamics in our model and show the drift of a scroll wave filament whose velocity depends non-monotonically on the fiber rotation angle; the period of scroll wave rotation decreases with an increase of the fiber rotation angle; an increase in anisotropy may cause the breakup of a scroll wave, similar to the mother rotor mechanism of ventricular fibrillation. PMID:24817308

  12. Structure and Functional Characteristics of Rat's Left Ventricle Cardiomyocytes under Antiorthostatic Suspension of Various Duration and Subsequent Reloading

    PubMed Central

    Ogneva, I. V.; Mirzoev, T. M.; Biryukov, N. S.; Veselova, O. M.; Larina, I. M.

    2012-01-01

    The goal of the research was to identify the structural and functional characteristics of the rat's left ventricle under antiorthostatic suspension within 1, 3, 7 and 14 days, and subsequent 3 and 7-day reloading after a 14-day suspension. The transversal stiffness of the cardiomyocyte has been determined by the atomic force microscopy, cell respiration—by polarography and proteins content—by Western blotting. Stiffness of the cortical cytoskeleton increases as soon as one day after the suspension and increases up to the 14th day, and starts decreasing during reloading, reaching the control level after 7 days. The stiffness of the contractile apparatus and the intensity of cell respiration also increases. The content of non-muscle isoforms of actin in the cytoplasmic fraction of proteins does not change during the whole experiment, as does not the beta-actin content in the membrane fraction. The content of gamma-actin in the membrane fraction correlates with the change in the transversal stiffness of the cortical cytoskeleton. Increased content of alpha-actinin-1 and alpha-actinin-4 in the membrane fraction of proteins during the suspension is consistent with increased gamma-actin content there. The opposite direction of change of alpha-actinin-1 and alpha-actinin-4 content suggests their involvement into the signal pathways. PMID:23093854

  13. Hyperthyroid dog left ventricle has the same oxygen consumption versus pressure-volume area (PVA) relation as euthyroid dog.

    PubMed

    Suga, H; Tanaka, N; Ohgoshi, Y; Saeki, Y; Nakanishi, T; Futaki, S; Yaku, H; Goto, Y

    1991-01-01

    We studied the effects of hyperthyroidism on the relation between O2 consumption (Vo2) and the pressure-volume area (PVA) of the left ventricle (LV) in dogs. PVA is a measure of the total mechanical energy generated per beat of LV. Dogs were treated by daily intramuscular injection of 0.3 or 1.0 mg/kg L-thyroxine over 2-5 weeks. Hyperthyroid dogs had a 40 times higher serum T4, a 40% higher sinus heart rate, and a 35% higher LV Emax (an index of ventricular contractility) than euthyroid dogs. Hyperthyroid dog hearts had linear Vo2-PVA relations like euthyroid dog hearts. The regression line was Vo2 = A x PVA + B, where A was 2.30 (dimensionless) and B was 0.53 J/beat per 100 g LV. B was significantly increased with dobutamine and decreased with propranolol, whereas A was not significantly changed by them. These A and B values were comparable to euthyroid data. Hyperthyroidism did not significantly affect myosin Ca-ATPase activity and V3-type myosin predominance, but increased the speed of the force transient response to length perturbation by 20%-70%, suggesting similar increases in crossbridge cycling rate. We conclude that in spite of accelerated crossbridge cycling rate the Vo2-PVA relation was not altered by hyperthyroidism in dogs. PMID:1830045

  14. Drift of Scroll Wave Filaments in an Anisotropic Model of the Left Ventricle of the Human Heart

    PubMed Central

    Pravdin, Sergei; Dierckx, Hans; Markhasin, Vladimir S.; Panfilov, Alexander V.

    2015-01-01

    Scroll waves are three-dimensional vortices which occur in excitable media. Their formation in the heart results in the onset of cardiac arrhythmias, and the dynamics of their filaments determine the arrhythmia type. Most studies of filament dynamics were performed in domains with simple geometries and generic description of the anisotropy of cardiac tissue. Recently, we developed an analytical model of fibre structure and anatomy of the left ventricle (LV) of the human heart. Here, we perform a systematic study of the dynamics of scroll wave filaments for the cases of positive and negative tension in this anatomical model. We study the various possible shapes of LV and different degree of anisotropy of cardiac tissue. We show that, for positive filament tension, the final position of scroll wave filament is mainly determined by the thickness of the myocardial wall but, however, anisotropy attracts the filament to the LV apex. For negative filament tension, the filament buckles, and for most cases, tends to the apex of the heart with no or slight dependency on the thickness of the LV. We discuss the mechanisms of the observed phenomena and their implications for cardiac arrhythmias. PMID:26539486

  15. Electrical wave propagation in an anisotropic model of the left ventricle based on analytical description of cardiac architecture.

    PubMed

    Pravdin, Sergey F; Dierckx, Hans; Katsnelson, Leonid B; Solovyova, Olga; Markhasin, Vladimir S; Panfilov, Alexander V

    2014-01-01

    We develop a numerical approach based on our recent analytical model of fiber structure in the left ventricle of the human heart. A special curvilinear coordinate system is proposed to analytically include realistic ventricular shape and myofiber directions. With this anatomical model, electrophysiological simulations can be performed on a rectangular coordinate grid. We apply our method to study the effect of fiber rotation and electrical anisotropy of cardiac tissue (i.e., the ratio of the conductivity coefficients along and across the myocardial fibers) on wave propagation using the ten Tusscher-Panfilov (2006) ionic model for human ventricular cells. We show that fiber rotation increases the speed of cardiac activation and attenuates the effects of anisotropy. Our results show that the fiber rotation in the heart is an important factor underlying cardiac excitation. We also study scroll wave dynamics in our model and show the drift of a scroll wave filament whose velocity depends non-monotonically on the fiber rotation angle; the period of scroll wave rotation decreases with an increase of the fiber rotation angle; an increase in anisotropy may cause the breakup of a scroll wave, similar to the mother rotor mechanism of ventricular fibrillation. PMID:24817308

  16. Fluid-structure interaction of an aortic heart valve prosthesis driven by an animated anatomic left ventricle

    PubMed Central

    Le, Trung Bao; Sotiropoulos, Fotis

    2012-01-01

    We develop a novel large-scale kinematic model for animating the left ventricle (LV) wall and use this model to drive the fluid-structure interaction (FSI) between the ensuing blood flow and a mechanical heart valve prosthesis implanted in the aortic position of an anatomic LV/aorta configuration. The kinematic model is of lumped type and employs a cell-based, FitzHugh-Nagumo framework to simulate the motion of the LV wall in response to an excitation wavefront propagating along the heart wall. The emerging large-scale LV wall motion exhibits complex contractile mechanisms that include contraction (twist) and expansion (untwist). The kinematic model is shown to yield global LV motion parameters that are well within the physiologic range throughout the cardiac cycle. The FSI between the leaflets of the mechanical heart valve and the blood flow driven by the dynamic LV wall motion and mitral inflow is simulated using the curvilinear immersed boundary (CURVIB) method [1, 2] implemented in conjunction with a domain decomposition approach. The computed results show that the simulated flow patterns are in good qualitative agreement with in vivo observations. The simulations also reveal complex kinematics of the valve leaflets, thus, underscoring the need for patient-specific simulations of heart valve prosthesis and other cardiac devices. PMID:23729841

  17. First third filling parameters of left ventricle assessed from gated equilibrium studies in patients with various heart diseases

    SciTech Connect

    Adatepe, M.H.; Nichols, K.; Powell, O.M.; Isaacs, G.H.

    1984-01-01

    The authors determined the first third filling fraction (1/3 FF), the maximum filling rate (1/3 FR) and the mean filling rate (1/3 MFR) for the first third diastolic filling period of the left ventricle in patients with coronary artery disease (CAD), valvular heart disease (VHD), pericardial effusion (PE), cardiomyopathies (CM), chronic obstructive lung disease (COPD) and in 5 normals-all from resting gated equilibrium studies. Parameters are calculated from the third order Fourier fit to the LV volume curve and its derivative. 1/3 FF% = 1/3 diastolic count - end systolic count / 1/3 diastolic count x 100. Patients with CAD are divided into two groups: Group I with normal ejection fraction (EF) and wall motion (WM); Group II with abnormal EF and WM. Results are shown in the table. Abnormal filling parameters are found not only in CAD but in VHD, PE and CM. The authors conclude that the first third LV filling parameters are sensitive but non-specific indicators of filling abnormalities caused by diverse etiologic factors. Abnormal first third filling parameters may occur in the presence of a normal resting EF and WM in CAD.

  18. Finite Element Interface to Linear Solvers

    SciTech Connect

    Williams, Alan

    2005-03-18

    Sparse systems of linear equations arise in many engineering applications, including finite elements, finite volumes, and others. The solution of linear systems is often the most computationally intensive portion of the application. Depending on the complexity of problems addressed by the application, there may be no single solver capable of solving all of the linear systems that arise. This motivates the desire to switch an application from one solver librwy to another, depending on the problem being solved. The interfaces provided by solver libraries differ greatly, making it difficult to switch an application code from one library to another. The amount of library-specific code in an application Can be greatly reduced by having an abstraction layer between solver libraries and the application, putting a common "face" on various solver libraries. One such abstraction layer is the Finite Element Interface to Linear Solvers (EEl), which has seen significant use by finite element applications at Sandia National Laboratories and Lawrence Livermore National Laboratory.

  19. Visualizing higher order finite elements. Final report

    SciTech Connect

    Thompson, David C; Pebay, Philippe Pierre

    2005-11-01

    This report contains an algorithm for decomposing higher-order finite elements into regions appropriate for isosurfacing and proves the conditions under which the algorithm will terminate. Finite elements are used to create piecewise polynomial approximants to the solution of partial differential equations for which no analytical solution exists. These polynomials represent fields such as pressure, stress, and momentum. In the past, these polynomials have been linear in each parametric coordinate. Each polynomial coefficient must be uniquely determined by a simulation, and these coefficients are called degrees of freedom. When there are not enough degrees of freedom, simulations will typically fail to produce a valid approximation to the solution. Recent work has shown that increasing the number of degrees of freedom by increasing the order of the polynomial approximation (instead of increasing the number of finite elements, each of which has its own set of coefficients) can allow some types of simulations to produce a valid approximation with many fewer degrees of freedom than increasing the number of finite elements alone. However, once the simulation has determined the values of all the coefficients in a higher-order approximant, tools do not exist for visual inspection of the solution. This report focuses on a technique for the visual inspection of higher-order finite element simulation results based on decomposing each finite element into simplicial regions where existing visualization algorithms such as isosurfacing will work. The requirements of the isosurfacing algorithm are enumerated and related to the places where the partial derivatives of the polynomial become zero. The original isosurfacing algorithm is then applied to each of these regions in turn.

  20. Finite element radiation transport in one dimension

    SciTech Connect

    Painter, J.F.

    1997-05-09

    A new physics package solves radiation transport equations in one space dimension, multiple energy groups and directions. A discontinuous finite element method discretizes radiation intensity with respect to space and angle, and a continuous finite element method discretizes electron temperature `in space. A splitting method solves the resulting linear equations. This is a one-dimensional analog of Kershaw and Harte`s two-dimensional package. This package has been installed in a two-dimensional inertial confinement fusion code, and has given excellent results for both thermal waves and highly directional radiation. In contrast, the traditional discrete ordinate and spherical harmonic methods show less accurate results in both cases.

  1. Finite-element models of continental extension

    NASA Technical Reports Server (NTRS)

    Lynch, H. David; Morgan, Paul

    1990-01-01

    Numerical models of the initial deformation of extending continental lithosphere, computed to investigate the control of preexisting thermal and mechanical heterogeneities on the style of deformation, are presented. The finite element method is used to calculate deformation with a viscoelastic-plastic model for the lithosphere. Comparisons of the results of analytic models and finite-element models using this method show that good results may be obtained by the numerical technique, even with elements containing both brittle and viscoelastic sampling points. It is shown that the gross style of initial extensional deformation is controlled by the depth and width of the initial heterogeneity which localizes deformation.

  2. Analysis of flow within a left ventricle model fully assisted with continuous flow through the aortic valve.

    PubMed

    Yano, Tetsuya; Funayama, Masanori; Sudo, Seiichi; Mitamura, Yoshinori

    2012-08-01

    Blood compatibility of a ventricular assist device (VAD) depends on the dynamics of blood flow. The focus in most previous studies was on blood flow in the VAD. However, the tip shape and position of the VAD inflow cannula influence the dynamics of intraventricular blood flow and thus thrombus formation in the ventricle. In this study, blood flow in the left ventricle (LV) under support with a catheter-type continuous flow blood pump was investigated. The flow field was analyzed both numerically and experimentally to investigate the effects of catheter tip shape and its insertion depth on intraventricular flow patterns. A computational model of the LV cavity with a simplified shape was constructed using computer-aided design software. Models of catheters with three different tip shapes were constructed and each was integrated to the LV model. In addition, three variations of insertion depth were prepared for all models. The fully supported intraventricular flow field was calculated by computational fluid dynamics (CFD). A transparent LV model made of silicone was also fabricated to analyze the intraventricular flow field by the particle image velocimetry technique. A mock circulation loop was constructed and water containing tracer particles was circulated in the loop. The motion of particles in the LV model was recorded with a digital high-speed video camera and analyzed to reveal the flow field. The results of numerical and experimental analyses indicated the formation of two large vortices in the bisector plane of the mitral and aortic valve planes. The shape and positioning of the catheter tip affected the flow distribution in the LV, and some of these combinations elongated the upper vortex toward the ventricular apex. Assessment based on average wall shear stress on the LV wall indicated that the flow distribution improved the washout effect. The flow patterns obtained from flow visualization coincided with those calculated by CFD analysis. Through these

  3. Studies of finite element analysis of composite material structures

    NASA Technical Reports Server (NTRS)

    Douglas, D. O.; Holzmacher, D. E.; Lane, Z. C.; Thornton, E. A.

    1975-01-01

    Research in the area of finite element analysis is summarized. Topics discussed include finite element analysis of a picture frame shear test, BANSAP (a bandwidth reduction program for SAP IV), FEMESH (a finite element mesh generation program based on isoparametric zones), and finite element analysis of a composite bolted joint specimens.

  4. Total Mechanical Unloading Minimizes Metabolic Demand of Left Ventricle and Dramatically Reduces Infarct Size in Myocardial Infarction

    PubMed Central

    Kakino, Takamori; Arimura, Takahiro; Sakamoto, Takafumi; Nishikawa, Takuya; Sakamoto, Kazuo; Ikeda, Masataka; Kishi, Takuya; Ide, Tomomi; Sunagawa, Kenji

    2016-01-01

    Background Left ventricular assist device (LVAD) mechanically unloads the left ventricle (LV). Theoretical analysis indicates that partial LVAD support (p-LVAD), where LV remains ejecting, reduces LV preload while increases afterload resulting from the elevation of total cardiac output and mean aortic pressure, and consequently does not markedly decrease myocardial oxygen consumption (MVO2). In contrast, total LVAD support (t-LVAD), where LV no longer ejects, markedly decreases LV preload volume and afterload pressure, thereby strikingly reduces MVO2. Since an imbalance in oxygen supply and demand is the fundamental pathophysiology of myocardial infarction (MI), we hypothesized that t-LVAD minimizes MVO2 and reduces infarct size in MI. The purpose of this study was to evaluate the differential impact of the support level of LVAD on MVO2 and infarct size in a canine model of ischemia-reperfusion. Methods In 5 normal mongrel dogs, we examined the impact of LVAD on MVO2 at 3 support levels: Control (no LVAD support), p-LVAD and t-LVAD. In another 16 dogs, ischemia was induced by occluding major branches of the left anterior descending coronary artery (90 min) followed by reperfusion (300 min). We activated LVAD from the beginning of ischemia until 300 min of reperfusion, and compared the infarct size among 3 different levels of LVAD support. Results t-LVAD markedly reduced MVO2 (% reduction against Control: -56 ± 9%, p<0.01) whereas p-LVAD did less (-21 ± 14%, p<0.05). t-LVAD markedly reduced infarct size compared to p-LVAD (infarct area/area at risk: Control; 41.8 ± 6.4, p-LVAD; 29.1 ± 5.6 and t-LVAD; 5.0 ± 3.1%, p<0.01). Changes in creatine kinase-MB paralleled those in infarct size. Conclusions Total LVAD support that minimizes metabolic demand maximizes the benefit of LVAD in the treatment of acute myocardial infarction. PMID:27124411

  5. Finite element displacement analysis of a lung.

    NASA Technical Reports Server (NTRS)

    Matthews, F. L.; West, J. B.

    1972-01-01

    A method is given based on the technique of finite elements which determines theoretically the mechanical behavior of a lung-shaped body loaded by its own weight. The results of this theoretical analysis have been compared with actual measurements of alveolar size and pleural pressures in animal lungs.

  6. Animation of finite element models and results

    NASA Technical Reports Server (NTRS)

    Lipman, Robert R.

    1992-01-01

    This is not intended as a complete review of computer hardware and software that can be used for animation of finite element models and results, but is instead a demonstration of the benefits of visualization using selected hardware and software. The role of raw computational power, graphics speed, and the use of videotape are discussed.

  7. Assignment Of Finite Elements To Parallel Processors

    NASA Technical Reports Server (NTRS)

    Salama, Moktar A.; Flower, Jon W.; Otto, Steve W.

    1990-01-01

    Elements assigned approximately optimally to subdomains. Mapping algorithm based on simulated-annealing concept used to minimize approximate time required to perform finite-element computation on hypercube computer or other network of parallel data processors. Mapping algorithm needed when shape of domain complicated or otherwise not obvious what allocation of elements to subdomains minimizes cost of computation.

  8. Precise survival time and physical activity after fatal left ventricle injury from sharp pointed weapon: a case report and a review of the literature.

    PubMed

    Franchi, Angélique; Kolopp, Martin; Coudane, Henry; Martrille, Laurent

    2016-09-01

    Survival time and physical activity following fatal injury are especially important during investigation of homicide cases and the estimation of a victim's survival time and physical activity following a fatal injury from a sharp weapon is a commonly raised issue, particularly at trial. According to the literature, survival time and physical activity after cardiac damage are short-term estimates without high accuracy. We report the homicide case of a young man who died as a result of a left ventricle injury caused by a sharp pointed weapon. This case is based on evidence from a video surveillance camera that recorded the whole scene after the fatal injury: The victim showed an adapted physical activity for 38 s, although the left ventricle incision measured 2 cm. Despite several cases in the literature, it is not possible to correlate precisely the size of the wounds and the acting capability. PMID:26914799

  9. Finite Element Simulation of Smart Structures

    NASA Technical Reports Server (NTRS)

    Cui, Y. Lawrence; Panahandeh, M.

    1996-01-01

    Finite element equations representing the behavior of piezoelectric materials when bounded to a typical structure and used as sensors and actuators were developed. Emphasis was placed on generating sensor output equations of piezoelectric sensors and responses of a typical structure bonded with piezoelectric sensors and actuators on the basis of finite element formulation. The model can predict not only structural responses due to both mechanical and electrical loading but also electrical potential due to mechanical or thermal effects. The resulted finite element equations were then used for simple control design and performance evaluation. In the control algorithm, voltages coming out from piezoelectric sensors, which are proportional to strains at sensing locations, are taken as input. The voltages applied to the piezoelectric actuators are used as output. The feasibility of integrating control algorithm with the element routine developed herein and FEAP was demonstrated. In particular, optimal independent modal space control was implemented in a software package on the basis of finite element formulation. A rudimentary finite element-control algorithm package was also developed to evaluate the performance of candidate control laws. A few numerical simulations using the software package developed herein were given. The integrated software package will provide a design tool to address issues such as how adaptive smart systems will scale to a full size aircraft, the amount of piezoelectric materials and the powers needed to actuate it for desired performance. It will also provide a viable new structural control design concept for practical applications in large flexible structures such as aerospace vehicles and aircraft.

  10. Analysis of the stability of housekeeping gene expression in the left cardiac ventricle of rats submitted to chronic intermittent hypoxia.

    PubMed

    Julian, Guilherme Silva; Oliveira, Renato Watanabe de; Tufik, Sergio; Chagas, Jair Ribeiro

    2016-01-01

    Obstructive sleep apnea (OSA) has been associated with oxidative stress and various cardiovascular consequences, such as increased cardiovascular disease risk. Quantitative real-time PCR is frequently employed to assess changes in gene expression in experimental models. In this study, we analyzed the effects of chronic intermittent hypoxia (an experimental model of OSA) on housekeeping gene expression in the left cardiac ventricle of rats. Analyses via four different approaches-use of the geNorm, BestKeeper, and NormFinder algorithms; and 2-ΔCt (threshold cycle) data analysis-produced similar results: all genes were found to be suitable for use, glyceraldehyde-3-phosphate dehydrogenase and 18S being classified as the most and the least stable, respectively. The use of more than one housekeeping gene is strongly advised. RESUMO A apneia obstrutiva do sono (AOS) tem sido associada ao estresse oxidativo e a várias consequências cardiovasculares, tais como risco aumentado de doença cardiovascular. A PCR quantitativa em tempo real é frequentemente empregada para avaliar alterações na expressão gênica em modelos experimentais. Neste estudo, analisamos os efeitos da hipóxia intermitente crônica (um modelo experimental de AOS) na expressão de genes de referência no ventrículo cardíaco esquerdo de ratos. Análises a partir de quatro abordagens - uso dos algoritmos geNorm, BestKeeper e NormFinder e análise de dados 2-ΔCt (ciclo limiar) - produziram resultados semelhantes: todos os genes mostraram-se adequados para uso, sendo que gliceraldeído-3-fosfato desidrogenase e 18S foram classificados como o mais e o menos estável, respectivamente. A utilização de mais de um gene de referência é altamente recomendada. PMID:27383935

  11. Evaluation of state-of-the-art segmentation algorithms for left ventricle infarct from late Gadolinium enhancement MR images.

    PubMed

    Karim, Rashed; Bhagirath, Pranav; Claus, Piet; Housden, R James; Chen, Zhong; Karimaghaloo, Zahra; Sohn, Hyon-Mok; Lara Rodríguez, Laura; Vera, Sergio; Albà, Xènia; Hennemuth, Anja; Peitgen, Heinz-Otto; Arbel, Tal; Gonzàlez Ballester, Miguel A; Frangi, Alejandro F; Götte, Marco; Razavi, Reza; Schaeffter, Tobias; Rhode, Kawal

    2016-05-01

    Studies have demonstrated the feasibility of late Gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging for guiding the management of patients with sequelae to myocardial infarction, such as ventricular tachycardia and heart failure. Clinical implementation of these developments necessitates a reproducible and reliable segmentation of the infarcted regions. It is challenging to compare new algorithms for infarct segmentation in the left ventricle (LV) with existing algorithms. Benchmarking datasets with evaluation strategies are much needed to facilitate comparison. This manuscript presents a benchmarking evaluation framework for future algorithms that segment infarct from LGE CMR of the LV. The image database consists of 30 LGE CMR images of both humans and pigs that were acquired from two separate imaging centres. A consensus ground truth was obtained for all data using maximum likelihood estimation. Six widely-used fixed-thresholding methods and five recently developed algorithms are tested on the benchmarking framework. Results demonstrate that the algorithms have better overlap with the consensus ground truth than most of the n-SD fixed-thresholding methods, with the exception of the Full-Width-at-Half-Maximum (FWHM) fixed-thresholding method. Some of the pitfalls of fixed thresholding methods are demonstrated in this work. The benchmarking evaluation framework, which is a contribution of this work, can be used to test and benchmark future algorithms that detect and quantify infarct in LGE CMR images of the LV. The datasets, ground truth and evaluation code have been made publicly available through the website: https://www.cardiacatlas.org/web/guest/challenges. PMID:26891066

  12. Right aortic arch with isolation of the left innominate artery in a case of double chamber right ventricle and ventricular septal defect.

    PubMed

    Mangukia, Chirantan; Sethi, Sonali; Agarwal, Saket; Mishra, Smita; Satsangi, Deepak Kumar

    2014-05-01

    Herein, we report an unusual case of right aortic arch with isolation of the left innominate artery in a case of double chamber right ventricle with ventricular septal defect. The blood supply to the innominate artery was by a collateral arising from the descending aorta. The embryological development of this anomaly can be explained by the hypothetical double aortic arch model proposed by Edwards with interruption of the arch at two levels. PMID:24987265

  13. Isothiocyanates Ameliorate the Symptom of Heart Dysfunction and Mortality in a Murine AIDS Model by Inhibiting Apoptosis in the Left Ventricle

    PubMed Central

    Ho, Jin-Nyoung; Yoon, Ho-Geun; Park, Chang-Soo; Kim, Sunoh; Jun, Woojin; Choue, Ryowon

    2012-01-01

    Abstract Cardiac involvement has been reported in as many as 45–55% of patients with human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS), and significant cardiac morbidity is reported in 6–7% of HIV patients. We investigated the inhibitory effects of isothiocyanates (ITCs) on heart dysfunction and mortality by regulating apoptosis in the left ventricle of the heart in a murine AIDS model. Mice were divided into six groups: an uninfected group, an untreated LP-BM5 retrovirus-infected group, and four LP-BM5 retrovirus-infected groups treated with one of four ITCs (sulforaphane [SUL], indolo[3,2-b]carbazole, benzyl isothiocyanate [BITC], or phenethyl isothiocyanate [PEITC]). After 16 weeks, the median survival time of the LP-BM5 retrovirus-infected mice was 87 days, whereas that of the uninfected control group and all ITC treatment groups was over 112 days. SUL, PEITC, and BITC significantly inhibited apoptosis in the left ventricle by increasing the Bcl-2/Bax ratio compared with LP-BM5-infected mice. In addition, SUL and PEITC suppressed inducible nitric oxide synthase (iNOS) expression at both the mRNA and protein levels in the left ventricle of heart tissue infected with the LP-BM5 retrovirus by inactivating cytoplasmic nuclear factor κB (NF-κB). In conclusion, LP-BM5 retrovirus infection was related to survival of murine AIDS mice, and NF-κB-mediated iNOS expression may be an important mediator of left ventricle dysfunction of the heart. Furthermore, certain ITCs may have the potential to improve AIDS-related heart dysfunction due to their inhibition of apoptosis by decreasing iNOS and Bax expression through suppression of NF-κB. PMID:22925072

  14. A biplane roentgen videometry system for dynamic /60 per second/ studies of the shape and size of circulatory structures, particularly the left ventricle.

    NASA Technical Reports Server (NTRS)

    Ritman, E. L.; Sturm, E.; Wood, E. H.; Heintzen, P. H.

    1971-01-01

    A roentgen-television digital-computer technique and a display system developed for dynamic circulatory structure studies are described. Details are given for a videoroentgenographic setup which is used for obtaining biplane roentgen silhouettes of a left ventricle. A 60 per sec measurement of the shape and volume of angiographically outlined cardiac chambers can be made by this technique along with simultaneous ECG, pressure, and flow measurements accessible for real-time digital computer processing and analysis.

  15. Acute pressure overload of the right ventricle. Comparison of two models of right-left shunt. Pulmonary artery to left atrium and right atrium to left atrium: experimental study

    PubMed Central

    2011-01-01

    Abtract Background In right ventricular failure (RVF), an interatrial shunt can relieve symptoms of severe pulmonary hypertension by reducing right ventricular preload and increasing systemic flow. Using a pig model to determine if a pulmonary artery - left atrium shunt (PA-LA) is better than a right atrial - left atrial shunt (RA-LA), we compared the hemodynamic effects and blood gases between the two shunts. Methods Thirty, male Large White pigs weighting in average 21.3 kg ± 0.7 (SEM) were divided into two groups (15 pigs per group): In group 1, banding of the pulmonary artery and a pulmonary artery to left atrium shunt with an 8 mm graft (PA-LA) was performed and in group 2 banding of the pulmonary artery and right atrial to left atrial shunt (RA-LA) with a similar graft was performed. Hemodynamic parameters and blood gases were measured from all cardiac chambers in 10 and 20 minutes, half and one hour interval from the baseline (30 min from the banding). Cardiac output and flow of at the left anterior descending artery was also monitored. Results In both groups, a stable RVF was generated. The PA-LA shunt compared to the RA-LA shunt has better hemodynamic performance concerning the decreased right ventricle afterload, the 4 fold higher mean pressure of the shunt, the better flow in left anterior descending artery and the decreased systemic vascular resistance. Favorable to the PA-LA shunt is also the tendency - although not statistically significant - in relation to central venous pressure, left atrial filling and cardiac output. Conclusion The PA-LA shunt can effectively reverse the catastrophic effects of acute RVF offering better hemodynamic characteristics than an interatrial shunt. PMID:22011551

  16. Finite Element Analysis of Honeycomb Impact Attenuator

    NASA Astrophysics Data System (ADS)

    Yang, Seung-Yong; Choi, Seung-Kyu; Kim, Nohyu

    To participate in Student Formula Society of Automotive Engineers (SAE) competitions, it is necessary to build an impact attenuator that would give an average deceleration not to exceed 20g when it runs into a rigid wall. Students can use numerical simulations or experimental test data to show that their car satisfies this safety requirement. A student group to study formula cars at the Korea University of Technology and Education has designed a vehicle to take part in a SAE competition, and a honeycomb structure was adopted as the impact attenuator. In this paper, finite element calculations were carried out to investigate the dynamic behavior of the honeycomb attenuator. Deceleration and deformation behaviors were studied. Effect of the yield strength was checked by comparing the numerical results. ABAQUS/Explicit finite element code was used.

  17. Revolution in Orthodontics: Finite element analysis

    PubMed Central

    Singh, Johar Rajvinder; Kambalyal, Prabhuraj; Jain, Megha; Khandelwal, Piyush

    2016-01-01

    Engineering has not only developed in the field of medicine but has also become quite established in the field of dentistry, especially Orthodontics. Finite element analysis (FEA) is a computational procedure to calculate the stress in an element, which performs a model solution. This structural analysis allows the determination of stress resulting from external force, pressure, thermal change, and other factors. This method is extremely useful for indicating mechanical aspects of biomaterials and human tissues that can hardly be measured in vivo. The results obtained can then be studied using visualization software within the finite element method (FEM) to view a variety of parameters, and to fully identify implications of the analysis. This is a review to show the applications of FEM in Orthodontics. It is extremely important to verify what the purpose of the study is in order to correctly apply FEM. PMID:27114948

  18. Visualization of higher order finite elements.

    SciTech Connect

    Thompson, David C.; Pebay, Philippe Pierre; Crawford, Richard H.; Khardekar, Rahul Vinay

    2004-04-01

    Finite element meshes are used to approximate the solution to some differential equation when no exact solution exists. A finite element mesh consists of many small (but finite, not infinitesimal or differential) regions of space that partition the problem domain, {Omega}. Each region, or element, or cell has an associated polynomial map, {Phi}, that converts the coordinates of any point, x = ( x y z ), in the element into another value, f(x), that is an approximate solution to the differential equation, as in Figure 1(a). This representation works quite well for axis-aligned regions of space, but when there are curved boundaries on the problem domain, {Omega}, it becomes algorithmically much more difficult to define {Phi} in terms of x. Rather, we define an archetypal element in a new coordinate space, r = ( r s t ), which has a simple, axis-aligned boundary (see Figure 1(b)) and place two maps onto our archetypal element:

  19. Verification of Orthogrid Finite Element Modeling Techniques

    NASA Technical Reports Server (NTRS)

    Steeve, B. E.

    1996-01-01

    The stress analysis of orthogrid structures, specifically with I-beam sections, is regularly performed using finite elements. Various modeling techniques are often used to simplify the modeling process but still adequately capture the actual hardware behavior. The accuracy of such 'Oshort cutso' is sometimes in question. This report compares three modeling techniques to actual test results from a loaded orthogrid panel. The finite element models include a beam, shell, and mixed beam and shell element model. Results show that the shell element model performs the best, but that the simpler beam and beam and shell element models provide reasonable to conservative results for a stress analysis. When deflection and stiffness is critical, it is important to capture the effect of the orthogrid nodes in the model.

  20. Finite element computation with parallel VLSI

    NASA Technical Reports Server (NTRS)

    Mcgregor, J.; Salama, M.

    1983-01-01

    This paper describes a parallel processing computer consisting of a 16-bit microcomputer as a master processor which controls and coordinates the activities of 8086/8087 VLSI chip set slave processors working in parallel. The hardware is inexpensive and can be flexibly configured and programmed to perform various functions. This makes it a useful research tool for the development of, and experimentation with parallel mathematical algorithms. Application of the hardware to computational tasks involved in the finite element analysis method is demonstrated by the generation and assembly of beam finite element stiffness matrices. A number of possible schemes for the implementation of N-elements on N- or n-processors (N is greater than n) are described, and the speedup factors of their time consumption are determined as a function of the number of available parallel processors.

  1. Plasticity - Theory and finite element applications.

    NASA Technical Reports Server (NTRS)

    Armen, H., Jr.; Levine, H. S.

    1972-01-01

    A unified presentation is given of the development and distinctions associated with various incremental solution procedures used to solve the equations governing the nonlinear behavior of structures, and this is discussed within the framework of the finite-element method. Although the primary emphasis here is on material nonlinearities, consideration is also given to geometric nonlinearities acting separately or in combination with nonlinear material behavior. The methods discussed here are applicable to a broad spectrum of structures, ranging from simple beams to general three-dimensional bodies. The finite-element analysis methods for material nonlinearity are general in the sense that any of the available plasticity theories can be incorporated to treat strain hardening or ideally plastic behavior.

  2. Finite element analysis of human joints

    SciTech Connect

    Bossart, P.L.; Hollerbach, K.

    1996-09-01

    Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described.

  3. Quadrilateral/hexahedral finite element mesh coarsening

    SciTech Connect

    Staten, Matthew L; Dewey, Mark W; Scott, Michael A; Benzley, Steven E

    2012-10-16

    A technique for coarsening a finite element mesh ("FEM") is described. This technique includes identifying a coarsening region within the FEM to be coarsened. Perimeter chords running along perimeter boundaries of the coarsening region are identified. The perimeter chords are redirected to create an adaptive chord separating the coarsening region from a remainder of the FEM. The adaptive chord runs through mesh elements residing along the perimeter boundaries of the coarsening region. The adaptive chord is then extracted to coarsen the FEM.

  4. Evolution of assumed stress hybrid finite element

    NASA Technical Reports Server (NTRS)

    Pian, T. H. H.

    1984-01-01

    Early versions of the assumed stress hybrid finite elements were based on the a priori satisifaction of stress equilibrium conditions. In the new version such conditions are relaxed but are introduced through additional internal displacement functions as Lagrange multipliers. A rational procedure is to choose the displacement terms such that the resulting strains are now of complete polynomials up to the same degree as that of the assumed stresses. Several example problems indicate that optimal element properties are resulted by this method.

  5. Finite element analysis of flexible, rotating blades

    NASA Technical Reports Server (NTRS)

    Mcgee, Oliver G.

    1987-01-01

    A reference guide that can be used when using the finite element method to approximate the static and dynamic behavior of flexible, rotating blades is given. Important parameters such as twist, sweep, camber, co-planar shell elements, centrifugal loads, and inertia properties are studied. Comparisons are made between NASTRAN elements through published benchmark tests. The main purpose is to summarize blade modeling strategies and to document capabilities and limitations (for flexible, rotating blades) of various NASTRAN elements.

  6. Finite element based electric motor design optimization

    NASA Technical Reports Server (NTRS)

    Campbell, C. Warren

    1993-01-01

    The purpose of this effort was to develop a finite element code for the analysis and design of permanent magnet electric motors. These motors would drive electromechanical actuators in advanced rocket engines. The actuators would control fuel valves and thrust vector control systems. Refurbishing the hydraulic systems of the Space Shuttle after each flight is costly and time consuming. Electromechanical actuators could replace hydraulics, improve system reliability, and reduce down time.

  7. Finite Element Analysis of Reverberation Chambers

    NASA Technical Reports Server (NTRS)

    Bunting, Charles F.; Nguyen, Duc T.

    2000-01-01

    The primary motivating factor behind the initiation of this work was to provide a deterministic means of establishing the validity of the statistical methods that are recommended for the determination of fields that interact in -an avionics system. The application of finite element analysis to reverberation chambers is the initial step required to establish a reasonable course of inquiry in this particularly data-intensive study. The use of computational electromagnetics provides a high degree of control of the "experimental" parameters that can be utilized in a simulation of reverberating structures. As the work evolved there were four primary focus areas they are: 1. The eigenvalue problem for the source free problem. 2. The development of a complex efficient eigensolver. 3. The application of a source for the TE and TM fields for statistical characterization. 4. The examination of shielding effectiveness in a reverberating environment. One early purpose of this work was to establish the utility of finite element techniques in the development of an extended low frequency statistical model for reverberation phenomena. By employing finite element techniques, structures of arbitrary complexity can be analyzed due to the use of triangular shape functions in the spatial discretization. The effects of both frequency stirring and mechanical stirring are presented. It is suggested that for the low frequency operation the typical tuner size is inadequate to provide a sufficiently random field and that frequency stirring should be used. The results of the finite element analysis of the reverberation chamber illustrate io-W the potential utility of a 2D representation for enhancing the basic statistical characteristics of the chamber when operating in a low frequency regime. The basic field statistics are verified for frequency stirring over a wide range of frequencies. Mechanical stirring is shown to provide an effective frequency deviation.

  8. Finite element modeling of nonisothermal polymer flows

    NASA Technical Reports Server (NTRS)

    Roylance, D.

    1981-01-01

    A finite element formulation designed to simulate polymer melt flows in which both conductive and convective heat transfer are important is described, and the numerical model is illustrated by means of computer experiments using extruder drag flow and entry flow as trial problems. Fluid incompressibility is enforced by a penalty treatment of the element pressures, and the thermal convective transport is modeled by conventional Galerkin and optimal upwind treatments.

  9. Finite element analysis of wrinkling membranes

    NASA Technical Reports Server (NTRS)

    Miller, R. K.; Hedgepeth, J. M.; Weingarten, V. I.; Das, P.; Kahyai, S.

    1984-01-01

    The development of a nonlinear numerical algorithm for the analysis of stresses and displacements in partly wrinkled flat membranes, and its implementation on the SAP VII finite-element code are described. A comparison of numerical results with exact solutions of two benchmark problems reveals excellent agreement, with good convergence of the required iterative procedure. An exact solution of a problem involving axisymmetric deformations of a partly wrinkled shallow curved membrane is also reported.

  10. ExodusII Finite Element Data Model

    Energy Science and Technology Software Center (ESTSC)

    2005-05-14

    EXODUS II is a model developed to store and retrieve data for finite element analyses. It is used for preprocessing (problem definition), postprocessing (results visualization), as well as code to code data transfer. An EXODUS II data file is a random access, machine independent, binary file that is written and read via C, C++, or Fortran library routines which comprise the Application Programming Interface. (exodus II is based on netcdf)