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Cardiac vortex

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https://www.readbyqxmd.com/read/29466325/electromechanical-vortex-filaments-during-cardiac-fibrillation
#1
J Christoph, M Chebbok, C Richter, J Schröder-Schetelig, P Bittihn, S Stein, I Uzelac, F H Fenton, G Hasenfuß, R F Gilmour, S Luther
Self-organized dynamics of vortex-like rotating waves or scroll waves underlie complex spatial-temporal pattern formation in many excitable chemical and biological systems1-4 . In the heart, filament-like phase singularities5,6 associated with three-dimensional scroll waves8 are considered to be the organizing centers of life-threatening cardiac arrhythmias7-13 . The mechanisms underlying the onset, perpetuation, and control14-16 of electromechanical turbulence in the heart are inherently three-dimensional phenomena...
February 21, 2018: Nature
https://www.readbyqxmd.com/read/29454583/post-operative-ventricular-flow-dynamics-following-atrioventricular-valve-surgical-and-device-therapies-a-review
#2
REVIEW
Yen Ngoc Nguyen, Munirah Ismail, Foad Kabinejadian, Edgar Lik Wui Tay, Hwa Liang Leo
Intra-ventricular flow dynamics has recently emerged as an important evaluation and diagnosis tool in different cardiovascular conditions. The formation of vortex pattern during the cardiac cycle has been suggested to play important epigenetic and energy-modulation roles in cardiac remodelling, adaptations and mal-adaptations. In this new perspective, flow alterations due to different cardiovascular procedures can affect the long-term outcome of those procedures. Especially, repairs and replacements performed on atrioventricular valves are likely to exert direct impact on intra-ventricular flow pattern...
February 14, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/29305613/optimized-time-resolved-echo-particle-image-velocimetry-particle-tracking-velocimetry-measurements-elucidate-blood-flow-in-patients-with-left-ventricular-thrombus
#3
Kaushik Sampath, Thura T Harfi, Richard T George, Joseph Katz
Contrast ultrasound is a widely used clinical tool to obtain real-time qualitative blood flow assessments in the heart, liver, etc. Echocardiographic particle image velocimetry (echo-PIV) is a technique for obtaining quantitative velocity maps from contrast ultrasound images. However, unlike optical particle image velocimetry (PIV), routine echo images are prone to nonuniform spatiotemporal variations in tracer distribution, making analysis difficult for standard PIV algorithms. This study introduces optimized procedures that integrate image enhancement, PIV, and particle tracking velocimetry (PTV) to obtain reliable time-resolved two-dimensional (2D) velocity distributions...
April 1, 2018: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/29230570/the-relationship-between-systolic-vector-flow-mapping-parameters-and-left-ventricular-cardiac-function-in-healthy-dogs
#4
Seijirow Goya, Tomoki Wada, Kazumi Shimada, Daiki Hirao, Ryou Tanaka
Vector flow mapping (VFM) is a novel echocardiographic technology that shows blood flow vectors and vortexes, enabled the hydrokinetic evaluation of hemodynamics within the left ventricle. VFM provides several unique parameters: circulation, vorticity, vortex area, and energy loss. The present study aims to reveal a relationship between VFM parameters and cardiac function. Five healthy Beagle dogs were anesthetized and administered with dobutamine (0, 2, 4, 8, 12 µg/kg/min). Pressure-volume diagrams were acquired to assess cardiac function using pressure-volume conductance catheter...
December 11, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/29217489/fixed-volume-particle-trace-emission-for-the-analysis-of-left-atrial-blood-flow-using-4d-flow-mri
#5
Stephen Gaeta, Petter Dyverfeldt, Jonatan Eriksson, Carl-Johan Carlhäll, Tino Ebbers, Ann F Bolger
4D Flow MRI has been used to quantify normal and deranged left ventricular blood flow characteristics on the basis of functionally distinct flow components. However, the application of this technique to the atria is challenging due to the presence of continuous inflow. This continuous inflow necessitates plane-based emission of particle traces from the inlet veins, leading to particles that represents different amounts of blood, and related quantification errors. The purpose of this study was to develop a novel fixed-volume approach for particle tracing and employ this method to develop quantitative analysis of 4D blood flow characteristics in the left atrium...
April 2018: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29098349/vortex-flow-in-the-right-atrium-surrogates-supraventricular-arrhythmia-and-thrombus-after-atriopulmonary-connection-type-fontan-operation-vortex-flow-analysis-using-conventional-cine-magnetic-resonance-imaging
#6
Yumi Shiina, Kei Inai, Tatsunori Takahashi, Yamato Shimomiya, Umiko Ishizaki, Kenji Fukushima, Michinobu Nagao
We developed a novel imaging technique, designated as vortex flow (VF) mapping, which presents a vortex flow visually on conventional two-dimensional (2D) cine MRI. Using it, we assessed circumferential VF patterns and influences on RA thrombus and supraventricular tachycardia (SVT) in AP connection-type Fontan circulation. Retrospectively, we enrolled 27 consecutive patients (25.1 ± 9.2 years) and 7 age-matched controls who underwent cardiac MRI. Conventional cine images acquired using a 1.5-Tesla scanner were scanned for axial and coronal cross section of the RA...
November 2, 2017: Pediatric Cardiology
https://www.readbyqxmd.com/read/29082600/analysis-of-left-ventricular-fluid-dynamics-in-dilated-cardiomyopathy-by-echocardiographic-particle-image-velocimetry
#7
Chouchou Tang, Yizhong Zhu, Jing Zhang, Chengcheng Niu, Dan Liu, Yacong Liao, Lijun Zhu, Qinghai Peng
OBJECTIVE: The aim was to analyze left ventricular (LV) fluid dynamics in dilated cardiomyopathy (DCM) by using echocardiographic particle image velocimetry (E-PIV). METHODS: Twenty patients with DCM and twenty healthy volunteers were examined. LV ultrasound contrast was administered by intravenous bolus injection. At least three dynamic contrast-enhanced echocardiographic images of cardiac cycles from apical three-chamber view and four-chamber view were obtained...
January 2018: Echocardiography
https://www.readbyqxmd.com/read/29060697/a-generic-cardiac-biventricular-fluid-electromechanics-model
#8
Azam Ahmad Bakir, Amr Al Abed, Nigel H Lovell, Socrates Dokos
We present a fully-coupled fluid-electromechanics model of the heart using a generic biventricular structure to provide a tool for future multiphysics interaction studies. A simplified Purkinje fibre structure was embedded within the myocardium along with transmural variation of action potential duration to obtain realistic activation and relaxation sequences. To ease computational requirements, phenomenological action potential and excitation-contraction formulations were chosen, and coupled to transverse isotropic hyperelastic myocardial material physics...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059653/blood-motion-turbulent-or-laminar
#9
Alla P Stepanchuk
INTRODUCTION: The issue on the mode of blood motion in the bloodstream, where the arterial and venous flow is significantly different, has been of greater concern recently. However, the conclusions are largely based on the analysis of the geometric orientation in the wall of arteries of smooth muscle elements. The aim of our study was to examine the characteristics of the prominent configuration of cardial cavities and arterial vessels. MATERIALS AND METHODS: The material for study were specimens of human heart, rabbit aorta and arterial microvessels of rat salivary glands, examined by injection and corrosive methods, scanning and transmission electron microscopy...
2017: Wiadomości Lekarskie: Organ Polskiego Towarzystwa Lekarskiego
https://www.readbyqxmd.com/read/28852976/experimental-study-of-right-ventricular-hemodynamics-after-tricuspid-valve-replacement-therapies-to-treat-tricuspid-regurgitation
#10
Yen Ngoc Nguyen, Munirah Ismail, Foad Kabinejadian, Chi Wei Ong, Edgar Lik Wui Tay, Hwa Liang Leo
The increased understanding of right heart diseases has led to more aggressive interventions to manage functional tricuspid regurgitation (FTR). In some cases of FTR, prosthetic valve replacement is typically considered when concomitant organic components or significant geometrical distortions are involved in the pathology of the tricuspid valve. However, little is known of the performance of current devices in the right heart circulation. In this study, a novel in vitro mock circulatory system that incorporated a realistic tricuspid valve apparatus in a patient-specific silicon right ventricle (RV) was designed and fabricated...
December 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28445281/relationship-between-the-abnormal-diastolic-vortex-structure-and-impaired-left-ventricle-filling-in-patients-with-hyperthyroidism
#11
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
#12
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...
June 2017: Journal of Cardiac Failure
https://www.readbyqxmd.com/read/28405398/mechanisms-of-vortices-termination-in-the-cardiac-muscle
#13
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
#14
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...
May 24, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28389690/energy-dynamics-of-the-intraventricular-vortex-after-mitral-valve-surgery
#15
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...
September 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
#16
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°)...
September 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
#17
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...
May 2017: Echocardiography
https://www.readbyqxmd.com/read/28239142/computational-analysis-of-intra-ventricular-flow-pattern-under-partial-and-full-support-of-bjut-ii-vad
#18
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
#19
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
#20
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
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