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Fluid dynamics of the heart

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https://www.readbyqxmd.com/read/29031174/dynamic-right-ventricular-outflow-obstruction-a-rare-cause-of-hypotension-during-anestesia-induction
#1
Maria Enrica Antoniucci, Christian Colizzi, Gabriella Arlotta, Maria Calabrese, Michele Corrado, Sergio Guarneri, Lorenzo Martinelli, Andrea Scapigliati, Roberto Zamparelli, Franco Cavaliere
INTRODUCTION: Dynamic obstruction of right ventricle outflow tract (RVOTO) is a rare condition that may acutely cause severe heart failure. It has been reported in some hypertrophic cardiomyopathies, after lung transplantation, and in some cases of hemodynamic instability after cardiopulmonary bypass. PRESENTATION OF CASE: We report the case of a 71-year-old man who developed severe hypotension during the induction of general anesthesia for surgical coronary revascularization...
October 5, 2017: International Journal of Surgery Case Reports
https://www.readbyqxmd.com/read/28971104/wave-intensity-analysis-and-its-application-to-the-coronary-circulation
#2
REVIEW
C J Broyd, J E Davies, J E Escaned, A Hughes, K Parker
Wave intensity analysis (WIA) is a technique developed from the field of gas dynamics that is now being applied to assess cardiovascular physiology. It allows quantification of the forces acting to alter flow and pressure within a fluid system, and as such it is highly insightful in ascribing cause to dynamic blood pressure or velocity changes. When co-incident waves arrive at the same spatial location they exert either counteracting or summative effects on flow and pressure. WIA however allows waves of different origins to be measured uninfluenced by other simultaneously arriving waves...
March 31, 2017: Global Cardiology Science & Practice
https://www.readbyqxmd.com/read/28964151/complex-blood-flow-patterns-in-an-idealized-left-ventricle-a-numerical-study
#3
Anna Tagliabue, Luca Dedè, Alfio Quarteroni
In this paper, we study the blood flow dynamics in a three-dimensional (3D) idealized left ventricle of the human heart whose deformation is driven by muscle contraction and relaxation in coordination with the action of the mitral and aortic valves. We propose a simplified but realistic mathematical treatment of the valves function based on mixed time-varying boundary conditions (BCs) for the Navier-Stokes equations modeling the flow. These switchings in time BCs, from natural to essential and vice versa, model either the open or the closed configurations of the valves...
September 2017: Chaos
https://www.readbyqxmd.com/read/28951296/a-fractionation-approach-applying-chelating-magnetic-nanoparticles-to-characterize-pericardial-fluid-s-proteome
#4
Fábio Trindade, Paulo Bastos, Adelino Leite-Moreira, Bruno Manadas, Rita Ferreira, Sofia F Soares, Ana L Daniel-da-Silva, Inês Falcão-Pires, Rui Vitorino
Owing to their close proximity, pericardial fluid (PF)'s proteome may mirror the pathophysiological status of the heart. Despite this diagnosis potential, the knowledge of PF's proteome is scarce. Large amounts of albumin hamper the characterization of the least abundant proteins in PF. Aiming to expand PF's proteome and to validate the technique for future applications, we have fractionated and characterized the PF, using N-(trimethoxysilylpropyl)ethylenediamine triacetic acid (EDTA)-functionalized magnetic nanoparticles (NPs@EDTA) followed by a GeLC-MS/MS approach...
September 23, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28945567/-cardiac-lymphatic-system
#5
Barbara Garmy-Susini, Nathalie Pizzinat, Nicole Villeneuve, Antoine Bril, Ebba Brakenhielm, Angelo Parini
The lymphatic system is a network of vessels and lymphoid tissues that maintain tissue fluid homeostasis, transport intestinal fat, and regulate immune surveillance. Despite a large body of evidence showing the importance of lymphatic vessels in cardiovascular diseases, the role of cardiac lymphatics has not been extensively investigated. This review highlights the chronology of key discoveries in cardiac lymphatic development and function. In physiology, the cardiac lymphatic system dynamically regulates interstitial fluid drainage to the mediastinal lymph nodes to maintain homeostasis and prevent edema...
August 2017: Médecine Sciences: M/S
https://www.readbyqxmd.com/read/28938307/design-and-development-of-a-miniaturized-percutaneously-deployable-wireless-left-ventricular-assist-device-early-prototypes-and-feasibility-testing
#6
Brian Letzen, Jiheum Park, Zeynep Tuzun, Pramod Bonde
The current left ventricular assist devices (LVADs) are limited by a highly invasive implantation procedure in a severely unstable group of advanced heart failure patients. Additionally, the current transcutaneous power drive line acts as a nidus for infection resulting in significant morbidity and mortality. In an effort to decrease this invasiveness and eliminate drive line complications, we have conceived a wireless miniaturized percutaneous LVAD, capable of being delivered endovascularly with a tether-free operation...
September 21, 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/28929446/new-imaging-tools-in-cardiovascular-medicine-computational-fluid-dynamics-and-4d-flow-mri
#7
Keiichi Itatani, Shohei Miyazaki, Tokoki Furusawa, Satoshi Numata, Sachiko Yamazaki, Kazuki Morimoto, Rina Makino, Hiroko Morichi, Teruyasu Nishino, Hitoshi Yaku
Blood flow imaging is a novel technology in cardiovascular medicine and surgery. Today, two types of blood flow imaging tools are available: measurement-based flow visualization including 4D flow MRI (or 3D cine phase-contrast magnetic resonance imaging), or echocardiography flow visualization software, and computer flow simulation modeling based on computational fluid dynamics (CFD). MRI and echocardiography flow visualization provide measured blood flow but have limitations in temporal and spatial resolution, whereas CFD flow calculates the flow according to assumptions instead of flow measurement, and it has sufficiently fine resolution up to the computer memory limit, and it enables even virtual surgery when combined with computer graphics...
September 19, 2017: General Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28929246/a-numerical-study-of-the-hemodynamic-effect-of-the-aortic-valve-on-coronary-flow
#8
Shaily Wald, Alex Liberzon, Idit Avrahami
During diastole, coronary perfusion depends on the pressure drop between the myocardial tissue and the coronary origin located at the aortic root. This pressure difference is influenced by the flow field near the closing valve leaflets. Clinical evidence is conclusive that patients with severe aortic stenosis (AS) suffer from diastolic dysfunction during hyperemia, but show increased coronary blood flow (CBF) during rest. Transcatheter aortic valve implantation (TAVI) was shown to decrease rest CBF along with its main purpose of improving the aortic flow and reducing the risk of heart failure...
September 19, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28868168/validity-of-pulse-pressure-variation-ppv-compared-with-stroke-volume-variation-svv-in-predicting-fluid-responsiveness
#9
Abhishek Rathore, Shalendra Singh, Ritesh Lamsal, Priya Taank, Debashish Paul
OBJECTIVE: Static monitors for assessing the fluid status during major surgeries and in critically ill patients have been gradually replaced by more accurate dynamic monitors in modern-day anaesthesia practice. Pulse pressure variation (PPV) and systolic pressure variation (SPV) are the two commonly used dynamic indices for assessing fluid responsiveness. METHODS: In this prospective observational study, 50 patients undergoing major surgeries were monitored for PPV and SPV: after the induction of anaesthesia and after the administration of 500 mL of isotonic crystalloid bolus...
August 2017: Turkish Journal of Anaesthesiology and Reanimation
https://www.readbyqxmd.com/read/28843327/role-of-computational-modelling-in-planning-and-executing-interventional-procedures-for-congenital-heart-disease
#10
REVIEW
Timothy C Slesnick
Increasingly, computational modelling and numerical simulations are used to help plan complex surgical and interventional cardiovascular procedures in children and young adults with congenital heart disease. From its origins more than 30 years ago, surgical planning with analysis of flow hemodynamics and energy loss/efficiency has helped design and implement many modifications to existing techniques. On the basis of patient-specific medical imaging, surgical planning allows accurate model production that can then be manipulated in a virtual surgical environment, with the proposed solutions finally tested with advanced computational fluid dynamics to evaluate the results...
September 2017: Canadian Journal of Cardiology
https://www.readbyqxmd.com/read/28820467/aquaporin-4-functionality-and-virchow-robin-space-water-dynamics-physiological-model-for-neurovascular-coupling-and-glymphatic-flow
#11
REVIEW
Tsutomu Nakada, Ingrid L Kwee, Hironaka Igarashi, Yuji Suzuki
The unique properties of brain capillary endothelium, critical in maintaining the blood-brain barrier (BBB) and restricting water permeability across the BBB, have important consequences on fluid hydrodynamics inside the BBB hereto inadequately recognized. Recent studies indicate that the mechanisms underlying brain water dynamics are distinct from systemic tissue water dynamics. Hydrostatic pressure created by the systolic force of the heart, essential for interstitial circulation and lymphatic flow in systemic circulation, is effectively impeded from propagating into the interstitial fluid inside the BBB by the tightly sealed endothelium of brain capillaries...
August 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28812203/assessment-of-methodologies-to-calculate-intraventricular-pressure-differences-in-computational-models-and-patients
#12
Francisco J Londono-Hoyos, Abigail Swillens, Joris Van Cauwenberge, Brett Meyers, Maheswara Reddy Koppula, Pavlos Vlachos, Julio A Chirinos, Patrick Segers
Intraventricular pressure differences (IVPDs) govern left ventricular (LV) efficient filling and are a significant determinant of LV diastolic function. Our primary aim is to assess the performance of available methods (color M-mode (CMM) and 1D/2D MRI-based methods) to determine IVPDs from intracardiac flow measurements. Performance of three methods to calculate IVPDs was first investigated via an LV computational fluid dynamics (CFD) model. CFD velocity data were derived along a modifiable scan line, mimicking ultrasound/MRI acquisition of 1D (IVPDCMM/IVPD1D MRI) and 2D (IVPD2D MRI) velocity-based IVPD information...
August 16, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28800300/intraventricular-vector-flow-mapping-a-doppler-based-regularized-problem-with-automatic-model-selection
#13
Kondo Claude Assi, Etienne Gay, Christophe Chnafa, Simon Mendez, Franck Nicoud, Juan F P J Abascal, Pierre Lantelme, François Tournoux, Damien Garcia
We propose a regularized least-squares method for reconstructing 2D velocity vector fields within the left ventricular cavity from single-view color Doppler echocardiographic images. Vector flow mapping is formulated as a quadratic optimization problem based on an [Formula: see text]-norm minimization of a cost function composed of a Doppler data-fidelity term and a regularizer. The latter contains three physically interpretable expressions related to 2D mass conservation, Dirichlet boundary conditions, and smoothness...
August 11, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28795671/-two-dimensional-speckle-tracking-imaging-in-assessing-the-left-ventricular-systolic-function-and-its-dynamic-changes-of-patients-with-septic-shock
#14
Fei Yang, Yong Chen, Ruiqiang Zheng, Yong Ma, Haidi Yu, Wenjuan Zhang, Yang Zhang
OBJECTIVE: To evaluate early and dynamic changes of the left ventricular systolic function of patients with septic shock by two-dimensional speckle tracking imaging (2D-STI), and to provide guidance for treatment and prognosis. METHODS: Fifty-eight septic shock patients admitted to intensive care unit (ICU) of Subei People's Hospital from January 2016 to April 2017 were enrolled. The septic shock patients were given early fluid resuscitation. The left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), early diastolic mitral flow velocity/early diastolic mitral annular peak velocity (E/Em) were obtained by conventional echocardiography, and the left ventricular global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS) were obtained by 2D-STI before fluid resuscitation and 1, 3, 7, 14 days after fluid resuscitation...
August 2017: Zhonghua Wei Zhong Bing Ji Jiu Yi Xue
https://www.readbyqxmd.com/read/28782911/simulation-of-aortopulmonary-collateral-flow-in-fontan-patients-for-use-in-prediction-of-interventional-outcomes
#15
Petter Frieberg, Pia Sjöberg, Johan Revstedt, Einar Heiberg, Petru Liuba, Marcus Carlsson
PURPOSE: Patients with complex congenital heart disease may need to be converted to a Fontan circulation with systemic venous return surgically connected to the pulmonary circulation. These patients frequently form aortopulmonary collaterals (APC), that is arterial inflows to the pulmonary artery vascular tree. The aim of this study was to develop a method to calculate the effect of APC on the pulmonary flow distribution based on magnetic resonance imaging (MRI) measurements and computational fluid dynamics simulations in order to enable prediction of interventional outcomes in Fontan patients...
August 7, 2017: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28777391/design-and-numerical-evaluation-of-an-axial-partial-assist-blood-pump-for-chinese-and-other-heart-failure-patients
#16
Guang-Mao Liu, Dong-Hai Jin, Jian-Ye Zhou, Xi-Hang Jiang, Han-Song Sun, Yan Zhang, Hai-Bo Chen, Sheng-Shou Hu, Xing-Min Gui
A fully implantable axial left ventricular assist device LAP31 was developed for Chinese or other heart failure patients who need partial support. Based on the 5-Lpm total cardiac blood output of Chinese without heart failure disease, the design point of LAP31 was set to a flow rate of 3 Lpm with 100-mmHg pressure head. To achieve the required pressure head and good hemolytic performance, a structure that includes a spindly rotor hub and a diffuser with splitter and cantilevered main blades was developed. Computational fluid dynamics (CFD) was used to analyze the hydraulic and hemodynamic performance of LAP31...
August 2, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28751011/a-coupled-mitral-valve-left-ventricle-model-with-fluid-structure-interaction
#17
Hao Gao, Liuyang Feng, Nan Qi, Colin Berry, Boyce E Griffith, Xiaoyu Luo
Understanding the interaction between the valves and walls of the heart is important in assessing and subsequently treating heart dysfunction. This study presents an integrated model of the mitral valve (MV) coupled to the left ventricle (LV), with the geometry derived from in vivo clinical magnetic resonance images. Numerical simulations using this coupled MV-LV model are developed using an immersed boundary/finite element method. The model incorporates detailed valvular features, left ventricular contraction, nonlinear soft tissue mechanics, and fluid-mediated interactions between the MV and LV wall...
July 24, 2017: Medical Engineering & Physics
https://www.readbyqxmd.com/read/28744907/design-and-hemocompatibility-analysis-of-a-double-suction-injection-suspension-blood-pump-using-computational-fluid-dynamics-methods
#18
Yue Wu, Liangfan Zhu, Yun Luo
The blood pump has become a possible solution to heart diseases. For the prevention of device failure and hemocompatibility problems, a rotary pump with suspended bearing is a preferred solution. In our previous work, a novel injection suspension method has been introduced to levitate the rotor. The suspension method is totally passive. This study aims to apply this suspension method to a double-suction pump, and the property of the pump was investigated using computational fluid dynamics (CFD) methods. The flow field of the pump is simulated based on the SST k-ω turbulent model...
July 26, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28744840/organ-dynamics-and-fluid-dynamics-of-the-hh25-chick-embryonic-cardiac-ventricle-as-revealed-by-a-novel-4d-high-frequency-ultrasound-imaging-technique-and-computational-flow-simulations
#19
Sheldon Ho, Germaine Xin Yi Tan, Toon Jin Foo, Nhan Phan-Thien, Choon Hwai Yap
Past literature has provided evidence that a normal mechanical force environment of blood flow may guide normal development while an abnormal environment can lead to congenital malformations, thus warranting further studies on embryonic cardiovascular flow dynamics. In the current study, we developed a non-invasive 4D high-frequency ultrasound technique, and use it to analyze cardiovascular organ dynamics and flow dynamics. Three chick embryos at stage HH25 were scanned with high frequency ultrasound in cine-B-mode at multiple planes spaced at 0...
July 25, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28744828/review-of-numerical-methods-for-simulation-of-mechanical-heart-valves-and-the-potential-for-blood-clotting
#20
Mohamad Shukri Zakaria, Farzad Ismail, Masaaki Tamagawa, Ahmad Fazli Abdul Aziz, Surjatin Wiriadidjaja, Adi Azrif Basri, Kamarul Arifin Ahmad
Even though the mechanical heart valve (MHV) has been used routinely in clinical practice for over 60 years, the occurrence of serious complications such as blood clotting remains to be elucidated. This paper reviews the progress that has been made over the years in terms of numerical simulation method and the contribution of abnormal flow toward blood clotting from MHVs in the aortic position. It is believed that this review would likely be of interest to some readers in various disciplines, such as engineers, scientists, mathematicians and surgeons, to understand the phenomenon of blood clotting in MHVs through computational fluid dynamics...
July 26, 2017: Medical & Biological Engineering & Computing
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