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Cardiac vortex

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https://www.readbyqxmd.com/read/28445281/relationship-between-the-abnormal-diastolic-vortex-structure-and-impaired-left-ventricle-filling-in-patients-with-hyperthyroidism
#1
Bin-Yu Zhou, Ming-Xing Xie, Jing Wang, Xin-Fang Wang, Qing Lv, Man-Wei Liu, Shuang-Shuang Kong, Ping-Yu Zhang, Jin-Feng Liu
Intraventricular hydrodynamics plays an important role in evaluating cardiac function. Relationship between diastolic vortex and left ventricular (LV) filling is still rarely elucidated. The aim of this study was to evaluate the evolution of vortex during diastole in hyperthyroidism (HT) and explore the alteration of hydromechanics characteristics with sensitive indexes.Forty-three patients diagnosed with HT were classified into 2 groups according to whether myocardial damage existed: simple hyperthyroid group (HT1, n = 21) and thyrotoxic cardiomyopathy (HT2, n = 22)...
April 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28435004/improvements-in-left-ventricular-diastolic-mechanics-after-parachute-device-implantation-in-patients-with-ischemia-heart-failure-a-cardiac-computerized-tomographic-study
#2
Chun-Ho Yun, Jing-Yi Sun, Barry Templin, Shih-Hsuan Lin, Kuan-Ming Chen, Tung-Hsin Wu, Chung-Lieh Hung, Chun-Chieh Liu, Hsi-Hsien Hsu, Mohamad Amer Alaiti, Anas Fares, Anthony DeCicco, Hiram G Bezerra
BACKGROUND: Percutaneous ventricular restoration therapy with the use of a left ventricle (LV)-partitioning Parachute device has emerged as a clinical treatment option for LV apical aneurysm after extensive anterior myocardial infarction (AMI). We assessed changes of diastolic mechanics and functional improvements following LV Parachute device implantation by means of cardiac computerized tomography (CCT). METHODS AND RESULTS: CCT data were obtained from 28 patients before and after LV Parachute device implantation...
April 20, 2017: Journal of Cardiac Failure
https://www.readbyqxmd.com/read/28405398/mechanisms-of-vortices-termination-in-the-cardiac-muscle
#3
D Hornung, V N Biktashev, N F Otani, T K Shajahan, T Baig, S Berg, S Han, V I Krinsky, S Luther
We propose a solution to a long-standing problem: how to terminate multiple vortices in the heart, when the locations of their cores and their critical time windows are unknown. We scan the phases of all pinned vortices in parallel with electric field pulses (E-pulses). We specify a condition on pacing parameters that guarantees termination of one vortex. For more than one vortex with significantly different frequencies, the success of scanning depends on chance, and all vortices are terminated with a success rate of less than one...
March 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28395878/cerebral-aneurysm-blood-flow-simulations-are-sensitive-to-basic-solver-settings
#4
Kendall D Dennis, David F Kallmes, Dan Dragomir-Daescu
Computational modeling of peri-aneurysmal hemodynamics is typically carried out with commercial software without knowledge of the sensitivity of the model to variation in input values. For three aneurysm models, we carried out a formal sensitivity analysis and optimization strategy focused on variation in timestep duration and model residual error values and their impact on hemodynamic outputs. We examined the solution sensitivity to timestep sizes of 10(-3)s, 10(-4)s, and 10(-5)s while using model residual error values of 10(-4), 10(-5), and 10(-6) using ANSYS Fluent to observe compounding errors and to optimize solver settings for computational efficiency while preserving solution accuracy...
April 3, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28389690/energy-dynamics-of-the-intraventricular-vortex-after-mitral-valve-surgery
#5
Kouki Nakashima, Keiichi Itatani, Tadashi Kitamura, Norihiko Oka, Tetsuya Horai, Shohei Miyazaki, Masaki Nie, Kagami Miyaji
Mitral valve morphology after mitral valve surgery affects postoperative intraventricular flow patterns and long-term cardiac performance. We visualized ventricular flow by echocardiography vector flow mapping (VFM) to reveal the impact of different mitral valve procedures. Eleven cases of mechanical mitral valve replacement (nine in the anti-anatomical and two in the anatomical position), three bioprosthetic mitral valve replacements, and four mitral valve repairs were evaluated. The mean age at the procedure was 57...
April 7, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/28343891/an-investigation-on-the-effects-of-the-angles-between-the-mitral-and-aortic-orifice-during-diastolic-period-using-fsi
#6
Md Shamsul Arefin
BACKGROUND: It was well documented that the changes in the physiological structure of the heart can alter the hemodynamic behaviour of the human left ventricle. Although there were various imaging tools that can stipulate the blood flow characteristics inside the ventricle, but the effect of the variation in the angles between the mitral and aortic orifices were yet to be determined. Hence the primary focus of this paper was to use Fluid-Structure Interaction scheme throughout the diastolic phase to examine and determine the hemodynamic behaviour inside the cavity under various angles between the mitral and aortic orifices (50°, 55° and 60°)...
March 18, 2017: Pathophysiology: the Official Journal of the International Society for Pathophysiology
https://www.readbyqxmd.com/read/28332315/significant-increase-of-flow-kinetic-energy-in-nonresponders-patients-to-cardiac-resynchronization-therapy
#7
Sara Cimino, Dino Palombizio, Francesco Cicogna, Donatella Cantisani, Manuela Reali, Domenico Filomena, Valentina Petronilli, Carlo Iacoboni, Luciano Agati
BACKGROUNDS: It's still unclear if different patterns of intraventricular flow dynamics may be detected in patients nonresponders to cardiac resynchronization therapy (CRT) as compared to responders ones. Aim of this study was to evaluate the characteristics of left ventricular (LV) flow dynamics 6-months after CRT to identify Echo-particle imaging velocity (PIV) patterns were more frequently detected in nonresponders patients. METHODS: Thirty-two patients with dilated cardiomyopathy, undergoing CRT, were enrolled in this study...
March 23, 2017: Echocardiography
https://www.readbyqxmd.com/read/28239142/computational-analysis-of-intra-ventricular-flow-pattern-under-partial-and-full-support-of-bjut-ii-vad
#8
Qi Zhang, Bin Gao, Yu Chang
BACKGROUND Partial support, as a novel support mode, has been widely applied in clinical practice and widely studied. However, the precise mechanism of partial support of LVAD in the intra-ventricular flow pattern is unclear. MATERIAL AND METHODS In this study, a patient-specific left ventricular geometric model was reconstructed based on CT data. The intra-ventricular flow pattern under 3 simulated conditions - "heart failure", "partial support", and "full support" - were simulated by using fluid-structure interaction (FSI)...
February 27, 2017: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/28148318/utility-of-4d-flow-mapping-in-eisenmenger-syndrome-with-pulmonary-atresia
#9
Soha Romeih, Heba Aguib, Magdi Yacoub
Management of patients with Eisenmenger syndrome with pulmonary atresia is challenging because of the complexity of the structure-function relationship of the components of the syndrome. Multi-modality imaging including cardiac magnetic resonance (CMR) 4D Flow offers unprecedented opportunities to unravel, at least in part, some of these components, and thus help in the management of these patients. In this study, we describe the use of these integrated methods with particular reference to CMR 4D Flow in a patient with Eisenmenger syndrome and pulmonary atresia and outline both the utility and the limitations...
December 2016: Cardiology in the Young
https://www.readbyqxmd.com/read/28114013/wall-less-flow-phantoms-with-tortuous-vascular-geometries-design-principles-and-a-patient-specific-model-fabrication-example
#10
Chung Kit Ho, Adrian J Y Chee, Billy Y S Yiu, Anderson C O Tsang, Kwok Wing Chow, Alfred C H Yu
Flow phantoms with anatomically realistic geometry and high acoustic compatibility are valuable investigative tools in vascular ultrasound studies. Here, we present a new framework to fabricate ultrasound-compatible flow phantoms to replicate human vasculature that is tortuous, non-planar and branching in nature. This framework is based upon the integration of rapid prototyping and investment casting principles. A pedagogical walkthrough of our engineering protocol is presented in this paper using a patient-specific cerebral aneurysm model as an exemplar demonstration...
December 6, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27959808/wall-less-flow-phantoms-with-tortuous-vascular-geometries-design-principles-and-a-patient-specific-model-fabrication-example
#11
Chung Kit Ho, Adrian J Y Chee, Billy Y S Yiu, Anderson C O Tsang, Kwok Wing Chow, Alfred C H Yu
Flow phantoms with anatomically realistic geometry and high acoustic compatibility are valuable investigative tools in vascular ultrasound studies. Here, we present a new framework to fabricate ultrasound-compatible flow phantoms to replicate human vasculature that is tortuous, nonplanar, and branching in nature. This framework is based upon the integration of rapid prototyping and investment casting principles. A pedagogical walkthrough of our engineering protocol is presented in this paper using a patient-specific cerebral aneurysm model as an exemplar demonstration...
January 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27939353/three-dimensional-diastolic-blood-flow-in-the-left-ventricle
#12
Seyed Saeid Khalafvand, Eddie Yin-Kwee Ng, Liang Zhong, Tin-Kan Hung
Three-dimensional blood flow in a human left ventricle is studied via a computational analysis with magnetic resonance imaging of the cardiac motion. Formation, growth and decay of vortices during the myocardial dilation are analyzed with flow patterns on various diametric planes. They are dominated by momentum transfer during flow acceleration and deceleration through the mitral orifice. The posterior and anterior vortices form an asymmetric annular vortex at the mitral orifice, providing a smooth transition for the rapid inflow to the ventricle...
January 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/27913338/intracardiac-vortex-dynamics-by-high-frame-rate-doppler-vortography-in-vivo-comparison-with-vector-flow-mapping-and-4-d-flow-mri
#13
Julia Faurie, Mathilde Baudet, Kondo Claude Assi, Dominique Auger, Guillaume Gilbert, Francois Tournoux, Damien Garcia
Recent studies have suggested that intracardiac vortex flow imaging could be of clinical interest to early diagnose the diastolic heart function. Doppler vortography has been introduced as a simple color Doppler method to detect and quantify intraventricular vortices. This method is able to locate a vortex core based on the recognition of an antisymmetric pattern in the Doppler velocity field. Because the heart is a fast-moving organ, high frame rates are needed to decipher the whole blood vortex dynamics during diastole...
February 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27891172/vortex-analysis-of-intra-aneurismal-flow-in-cerebral-aneurysms
#14
Kevin Sunderland, Christopher Haferman, Gouthami Chintalapani, Jingfeng Jiang
This study aims to develop an alternative vortex analysis method by measuring structure ofIntracranial aneurysm (IA) flow vortexes across the cardiac cycle, to quantify temporal stability of aneurismal flow. Hemodynamics were modeled in "patient-specific" geometries, using computational fluid dynamics (CFD) simulations. Modified versions of known λ2 and Q-criterion methods identified vortex regions; then regions were segmented out using the classical marching cube algorithm. Temporal stability was measured by the degree of vortex overlap (DVO) at each step of a cardiac cycle against a cycle-averaged vortex and by the change in number of cores over the cycle...
2016: Computational and Mathematical Methods in Medicine
https://www.readbyqxmd.com/read/27866678/patient-specific-cfd-models-for-intraventricular-flow-analysis-from-3d-ultrasound-imaging-comparison-of-three-clinical-cases
#15
A M Bavo, A M Pouch, J Degroote, J Vierendeels, J H Gorman, R C Gorman, P Segers
BACKGROUND: As the intracardiac flow field is affected by changes in shape and motility of the heart, intraventricular flow features can provide diagnostic indications. Ventricular flow patterns differ depending on the cardiac condition and the exploration of different clinical cases can provide insights into how flow fields alter in different pathologies. METHODS: In this study, we applied a patient-specific computational fluid dynamics model of the left ventricle and mitral valve, with prescribed moving boundaries based on transesophageal ultrasound images for three cardiac pathologies, to verify the abnormal flow patterns in impaired hearts...
January 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/27848215/accuracy-and-limitations-of-vector-flow-mapping-left-ventricular-phantom-validation-using-stereo-particle-image-velocimetory
#16
Rei Asami, Tomohiko Tanaka, Ken-Ichi Kawabata, Kunio Hashiba, Takashi Okada, Tomohide Nishiyama
BACKGROUND: The accuracy of vector flow mapping (VFM) was investigated in comparison to stereo particle image velocimetry (stereo-PIV) measurements using a left ventricular phantom. VFM is an echocardiographic approach to visualizing two-dimensional flow dynamics by estimating the azimuthal component of flow from the mass-conservation equation. VFM provides means of visualizing cardiac flow, but there has not been a study that compared the flow estimated by VFM to the flow data acquired by other methods...
June 2017: Journal of Echocardiography
https://www.readbyqxmd.com/read/27796137/two-dimensional-intraventricular-flow-pattern-visualization-using-the-image-based-computational-fluid-dynamics
#17
Siamak N Doost, Liang Zhong, Boyang Su, Yosry S Morsi
The image-based computational fluid dynamics (IB-CFD) technique, as the combination of medical images and the CFD method, is utilized in this research to analyze the left ventricle (LV) hemodynamics. The research primarily aims to propose a semi-automated technique utilizing some freely available and commercial software packages in order to simulate the LV hemodynamics using the IB-CFD technique. In this research, moreover, two different physiological time-resolved 2D models of a patient-specific LV with two different types of aortic and mitral valves, including the orifice-type valves and integrated with rigid leaflets, are adopted to visualize the process of developing intraventricular vortex formation and propagation...
April 2017: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/27612951/patient-specific-cfd-simulation-of-intraventricular-haemodynamics-based-on-3d-ultrasound-imaging
#18
A M Bavo, A M Pouch, J Degroote, J Vierendeels, J H Gorman, R C Gorman, P Segers
BACKGROUND: The goal of this paper is to present a computational fluid dynamic (CFD) model with moving boundaries to study the intraventricular flows in a patient-specific framework. Starting from the segmentation of real-time transesophageal echocardiographic images, a CFD model including the complete left ventricle and the moving 3D mitral valve was realized. Their motion, known as a function of time from the segmented ultrasound images, was imposed as a boundary condition in an Arbitrary Lagrangian-Eulerian framework...
September 9, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/27501792/counter-clockwise-vortical-blood-flow-in-the-main-pulmonary-artery-in-a-patient-with-patent-ductus-arteriosus-with-pulmonary-arterial-hypertension-a-cardiac-magnetic-resonance-imaging-case-report
#19
Gert Reiter, Ursula Reiter, Gabor Kovacs, Gabriel Adelsmayr, Andreas Greiser, Aurelien F Stalder, Horst Olschewski, Michael Fuchsjäger
BACKGROUND: In patients with pulmonary hypertension (PH), duration of vortical blood flow along the main pulmonary artery enables estimation of the mean pulmonary arterial pressure (mPAP) non-invasively. It remains to date not known, if this method is applicable in patients with pulmonary arterial hypertension (PAH) and abnormal aortic-to-pulmonary shunting. CASE PRESENTATION: The present case analyzes the effect of a patent ductus arteriosus (PDA) on pulmonary artery flow patterns in PAH (mPAP from right heart catheterization, 75 mmHg)...
August 8, 2016: BMC Medical Imaging
https://www.readbyqxmd.com/read/26993615/cardiac-mri-based-numerical-modeling-of-left-ventricular-fluid-dynamics-with-mitral-valve-incorporated
#20
Boyang Su, Ru San Tan, Ju Le Tan, Kenneth Wei Qiang Guo, Jun Mei Zhang, Shuang Leng, Xiaodan Zhao, John Carson Allen, Liang Zhong
Recent numerical studies were focused on the modeling of flow in patient-specific left ventricle (LV); however, the mitral valve (MV) was usually excluded. In this study, both patient-specific LV and MV were modeled to achieve a more realistic intraventricular flow. Cardiac MRI images were acquired from a pulmonary arterial hypertension (PAH) patient and a healthy volunteer, and manual segmentation was conducted to reconstruct three-dimensional (3D) LV and MV geometries at each frame. Based on these 3D geometries, vortex formation time (VFT) was derived, and the values were 4...
May 3, 2016: Journal of Biomechanics
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