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Fluid dynamics of the heart

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https://www.readbyqxmd.com/read/29229579/investigation-of-the-pulsatility-of-cerebrospinal-fluid-using-cardiac-gated-intravoxel-incoherent-motion-imaging
#1
Anton S Becker, Andreas Boss, Markus Klarhoefer, Tim Finkenstaedt, Moritz C Wurnig, Cristina Rossi
The quantitative and non-invasive monitoring of cerebrospinal fluid (CSF) dynamics and composition may have high clinical relevance in the management of CSF disorders. In this study, we propose the use of the Intravoxel Incoherent Motion (IVIM) MRI for obtaining simultaneous measurements of CSF self-diffusion and fluid circulation. The rationale for this study was that turbulent fluid and mesoscopic fluid fluctuations can be modeled in a first approximation as a fast diffusion process. In this case, we expect that the fast fluid circulation and slower molecular diffusion dynamics can be quantified, assuming a bi-exponential attenuation pattern of the diffusion-weighted signal in MRI...
December 8, 2017: NeuroImage
https://www.readbyqxmd.com/read/29203173/evaluation-of-the-dynamic-predictors-of-fluid-responsiveness-in-dogs-receiving-goal-directed-fluid-therapy
#2
Maja J Drozdzynska, Yu-Mei Chang, Giacomo Stanzani, Ludovic Pelligand
OBJECTIVES: Goal-directed fluid therapy (GDFT) based on pulse pressure variation (PPV) was used in anaesthetized dogs undergoing abdominal surgeries. The aims were 1) to evaluate the success rate of the PPV ≥13% in detecting fluid responsiveness [delta stroke volume (ΔSV) ≥10%]; 2) to assess the correlation between PPV, systolic pressure variation (SPV), Plethysmograph Variability Index (PVI) and central venous pressure (CVP) and 3) to establish the threshold value for the PVI that would predict a PPV value of ≥13% and indirectly discriminate responders from nonresponders to fluid therapy...
June 17, 2017: Veterinary Anaesthesia and Analgesia
https://www.readbyqxmd.com/read/29183945/organ-size-control-via-hydraulically-gated-oscillations
#3
Teresa Ruiz-Herrero, Kévin Alessandri, Basile V Gurchenkov, Pierre Nassoy, L Mahadevan
Hollow vesicular tissues of various sizes and shapes arise in biological organs such as ears, guts, hearts, brains and even entire organisms. Regulating their size and shape is crucial for their function. Although chemical signaling has been thought to play a role in the regulation of cellular processes that feed into larger scales, it is increasingly recognized that mechanical forces are involved in the modulation of size and shape at larger length scales. Motivated by a variety of examples of tissue cyst formation and size control that show simultaneous growth and size oscillations, we create a minimal theoretical framework for the growth and dynamics of a soft, fluid-permeable, spherical shell...
December 1, 2017: Development
https://www.readbyqxmd.com/read/29181891/fluid-structure-interaction-of-a-pulsatile-flow-with-an-aortic-valve-model-a-combined-experimental-and-numerical-study
#4
J Sigüenza, D Pott, S Mendez, S J Sonntag, T A S Kaufmann, U Steinseifer, F Nicoud
The complex fluid-structure interaction problem associated with the flow of blood through a heart valve with flexible leaflets is investigated both experimentally and numerically. In the experimental test rig, a pulse duplicator generates a pulsatile flow through a biomimetic rigid aortic root where a model of aortic valve with polymer flexible leaflets is implanted. High-speed recordings of the leaflets motion and Particle Image Velocimetry measurements were performed together to investigate the valve kinematics and the dynamics of the flow...
November 27, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/29161412/fluid-dynamics-in-heart-development-effects-of-hematocrit-and-trabeculation
#5
Nicholas A Battista, Andrea N Lane, Jiandong Liu, Laura A Miller
Recent in vivo experiments have illustrated the importance of understanding the haemodynamics of heart morphogenesis. In particular, ventricular trabeculation is governed by a delicate interaction between haemodynamic forces, myocardial activity, and morphogen gradients, all of which are coupled to genetic regulatory networks. The underlying haemodynamics at the stage of development in which the trabeculae form is particularly complex, given the balance between inertial and viscous forces. Small perturbations in the geometry, scale, and steadiness of the flow can lead to changes in the overall flow structures and chemical morphogen gradients, including the local direction of flow, the transport of morphogens, and the formation of vortices...
November 16, 2017: Mathematical Medicine and Biology: a Journal of the IMA
https://www.readbyqxmd.com/read/29124548/development-of-an-experimental-and-digital-cardiovascular-arterial-model-for-transient-hemodynamic-and-postural-change-studies-a-preliminary-framework-analysis
#6
Rodward L Hewlin, John P Kizito
The ultimate goal of the present work is to aid in the development of tools to assist in the treatment of cardiovascular disease. Gaining an understanding of hemodynamic parameters for medical implants allow clinicians to have some patient-specific proposals for intervention planning. In the present work an experimental and digital computational fluid dynamics (CFD) arterial model consisting of a number of major arteries (aorta, carotid bifurcation, cranial, femoral, jejunal, and subclavian arteries) were fabricated to study: (1) the effects of local hemodynamics (flow parameters) on global hemodynamics (2) the effects of transition from bedrest to upright position (postural change) on hemodynamics, and (3) diffusion of dye (medical drug diffusion simulation) in the arterial system via experimental and numerical techniques...
November 9, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/29124390/the-liebau-phenomenon-a-translational-approach-to-new-paradigms-of-csf-circulation-and-related-flow-disturbances
#7
Pierluigi Longatti
PURPOSE: The aim of the study is to provide a comparison between Liebau's effect, underlying the working principles of impedance pumps, and the cerebrospinal fluid (CSF) circulation. METHODS: Gerhard Liebau was a cardiologist with a specific interest in severe aortic regurgitation. Such interest drew his scientific attention to the flow-driven efficiency of valveless pumps. During one of his experiments, he assembled two rubber tubes of different sizes and documented how water could be aspirated against gravity when the tube of larger diameter underwent rhythmic compression...
November 9, 2017: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
https://www.readbyqxmd.com/read/29122962/frequent-drinking-of-small-volumes-improves-cardiac-function-and-survival-in-rats-with-chronic-heart-failure
#8
Can Zheng, Meihua Li, Toru Kawada, Masashi Inagaki, Kazunori Uemura, Masaru Sugimachi
Fluid retention is the main reason for the high hospitalization rate among patients with chronic heart failure (CHF). Given the lack of knowledge about fluid intake regulation and its consequences in patients with CHF, current guidelines do not provide clear direction for fluid management. Using a rat model of CHF, we investigated altering drinking behaviors and explored fluid management strategies. CHF was induced by ligating the left anterior descending coronary arteries in 8-week-old, male, Sprague-Dawley rats...
November 2017: Physiological Reports
https://www.readbyqxmd.com/read/29098290/fluid-structure-interaction-models-of-bicuspid-aortic-valves-the-effects-of-non-fused-cusp-angles
#9
Karin Lavon, Rotem Halevi, Gil Marom, Sagit Ben Zekry, Ashraf Hamdan, Hans Joachim Schäfers, Ehud Raanani, Rami Haj-Ali
Bicuspid aortic valve (BAV) is the most common type of congenital heart disease, occurring in 0.5-2% of the population, where the valve has only two rather than the three normal cusps. Valvular pathologies, such as aortic regurgitation and aortic stenosis, are associated with BAVs, thereby increasing the need for a better understanding of BAV kinematics and geometrical characteristics. The aim of this study is to investigate the influence of the non-fused cusp (NFC) angle in BAV type-1 configuration on the valve's structural and hemodynamic performance...
November 2, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/29091053/multiscale-network-representation-of-physiological-time-series-for-early-prediction-of-sepsis
#10
Supreeth P Shashikumar, Qiao Li, Gari D Clifford, Shamim Nemati
Objective and Approach: Sepsis, a dysregulated immune-mediated host response to infection, is the leading cause of morbidity and mortality in critically ill patients. Indices of heart rate variability and complexity (such as entropy) have been proposed as surrogate markers of neuro-immune system dysregulation with diseases such as sepsis. However, these indices only provide an average, one dimensional description of complex neuro-physiological interactions. We propose a novel multiscale network construction and analysis method for multivariate physiological time series, and demonstrate its utility for early prediction of sepsis...
November 30, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/29082600/analysis-of-left-ventricular-fluid-dynamics-in-dilated-cardiomyopathy-by-echocardiographic-particle-image-velocimetry
#11
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...
October 29, 2017: Echocardiography
https://www.readbyqxmd.com/read/29080776/comprehensive-computational-assessment-of-blood-flow-characteristics-of-left-ventricle-based-on-in-vivo-mri-in-presence-of-artificial-myocardial-infarction
#12
Ali Imanparast, Nasser Fatouraee, Farhad Sharif
BACKGROUND: Understanding the effects of cardiac diseases on the heart's functionality which is the purpose of many biomedical researches, directly affects the diagnostic and therapeutic methods. Myocardial infarction (MI) is a common complication of cardiac ischemia, however, the impact of MI on the left ventricle (LV) flow patterns has not been widely considered by computational fluid dynamics studies thus far. METHODS: In this study, we present an insightful numerical method that creates an artificial MI on an image-based fluid-structure interactional model of normal LV to investigate its influence on the flow in comparison with the normal case...
October 26, 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/29076944/a-numerical-simulation-of-heartassist5-blood-pump-using-an-advanced-turbulence-model
#13
Primož Drešar, Marcel C M Rutten, Igor D Gregorič, Jožef Duhovnik
The need for mechanical assistance of the failing heart has increased with improvements in medicine and a rapidly aging population. In recent decades, significant progress has been made in the development and refinement of ventricular assist devices (VADs). Such devices operate in mixed laminar, transitional, and turbulent flow regime. One tool that assists in the development of VADs by facilitating understanding of the physical and mechanical properties of these flow regimes is computational fluid dynamics (CFD)...
October 23, 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/29031174/dynamic-right-ventricular-outflow-obstruction-a-rare-cause-of-hypotension-during-anestesia-induction
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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...
November 2017: General Thoracic and Cardiovascular Surgery
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