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  • cardiac
  • An automated, closed-loop 1D-0D modelling framework was developed, and we demonstrate its efficacy in (1) reproducing measured multi-variate cardiovascular variables (pulse pressure, total peripheral resistance and cardiac output) and (2) providing automated estimates of variables that have not been measured (uterine arterial and venous blood flow, pulse wave velocity, pulsatility index). (springer.com)
  • Using this model as a framework, results were analyzed for the four distinct phases of the cardiac cycle - diastole, isovolumic contraction, ejection and isovolumic relaxation. (biomedcentral.com)
  • Unique parameter identification for cardiac diagnosis in critical care using minimal data sets. (ac.be)
  • The simplified models can also act as a bridge to identifying more sophisticated cardiac models, by providing an initial set of patient specific parameters that can reveal trends and interactions in the data over time. (ac.be)
  • Cardiac contraction is modeled using the varying-elastance concept. (physiology.org)
  • In summary, the combined protocol strategy can be readily applied for quantitative TATS network studies during physiological myocyte adaptation or disease changes, comparison of different cardiac or skeletal muscle cell types, phenotyping of transgenic models, and pharmacological or therapeutic interventions. (jove.com)
  • The displacement field during the cardiac cycle is described by three time-dependent parameters, using a family of volume-preserving mappings based on prolate spheroidal coordinates. (deepdyve.com)
  • Stress equilibrium is imposed in weak form and the resulting force balance equations are coupled to a lumped-parameter model of the circulation, leading to a system of differential-algebraic equations, whose numerical solution yields predictions of LV pressure and volume, together with spatial distributions of stresses and strains throughout the cardiac cycle. (deepdyve.com)
  • This approach allows simulations of LV dynamics that run faster than real time, and could be used to determine patient-specific parameters of LV performance on-line from clinically available measurements, with the eventual goal of real-time, patient-specific analysis of cardiac parameters. (deepdyve.com)
  • This is a lumped parameter model for cardiac activation based on the work of Heldt et al. (cellml.org)
  • numerical
  • 4 ] and Singh and Shah [ 5 ] analyzed the decreases of instantaneous maximal transvalvular pressure in aortic stenosis using numerical models. (hindawi.com)
  • An analytical solution has been developed to model blood flow in tapering vessels and when compared with the numerical solution, showed excellent agreement. (biomedcentral.com)
  • To this end, numerical simulations were performed using acquired central pressure signals from different subject groups (young, adults, and hypertensive) as input and then comparing the output of the model with measured radial artery pressure waveforms. (hindawi.com)
  • Pathological conditions were modeled as changes in arterial elasticity ( E ). Numerical results showed that the model was able to propagate acquired pressure waveforms and to reproduce PPA variations as a consequence of elastic changes. (hindawi.com)
  • We also present a practical biomedical application of the developed numerical model to the problem of blood flow variability in cerebral circulation due to anatomical features of the vascular network in the presence of the atherosclerosis disease. (springer.com)
  • vascular
  • For the purpose of a better understanding of the correlation between vascular stenoses and ABI, a computational model for simulating blood pressure and flow propagation in various arterial stenosis circumstances was developed with a detailed compartmental description of the heart and main arteries. (hindawi.com)
  • The model will provide a basis for future studies aiming to elucidate the physiological mechanisms underlying the dynamic properties (changing shapes) of vascular flow waveforms that are observed with advancing gestation. (springer.com)
  • We believe that such a model could have clinical applications particularly with relation to mesenteric ischemia, a complex vascular problem that arises due to a narrowing or blockage of blood vessels that supply oxygenated blood to the small and large intestines, for which accurate diagnosis is often delayed. (biomedcentral.com)
  • It consists of a simplified fluid circuit with lumped parameter elements implemented in hardware (compliance chamber, vascular resistor, and venous reservoir). (forschung3r.ch)
  • The calculation and modeling of vascular input impedance are based on the assumption that pressure and flow are linearly related in the frequency domain. (ahajournals.org)
  • The calculation of vascular impedance by Fourier methods and Windkessel-type lumped parameter models is based on the assumption that pressure and flow are linearly related in the frequency domain. (ahajournals.org)
  • Both of these noninvasive measures of vascular dysfunction are independent predictors of future cardiovascular events in patients with and without kidney disease. (jove.com)
  • arterial
  • 1 - 3 ] developed finite element models including nonlinearities arising from geometry and material properties to analyze the characteristics of blood flow and pressure decrease caused by an arterial stenosis. (hindawi.com)
  • ABI, defined as the ratio of systolic pressure in the ankle arteries (the posterior tibial artery in this model) and systolic pressure in the brachial artery (Figure 1 ), was an important noninvasive measurement for the detection of arterial obstructive disease, especially for the lower extremity arterial stenosis [ 8 - 10 ]. (hindawi.com)
  • Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential therapies. (jove.com)
  • Arterial pressure waves have been described in one dimension using several approaches, such as lumped (Windkessel) or distributed (using Navier-Stokes equations) models. (hindawi.com)
  • We considered two models simulating drug delivery to the arterial wall: (i) two-dimensional drug-coated balloons and (ii) three-dimensional drug-eluting stents. (royalsocietypublishing.org)
  • hemodynamic
  • Models used in those studies were mostly applied to the analysis of hemodynamic effects of stenoses on blood pressure decreases or flow characteristics. (hindawi.com)
  • Although it is important to analyze the hemodynamic factors related to the right ventricle (RV) after left ventricular assist device (LVAD) implantation, previous studies have focused only on the alteration of the ventricular shape and lack quantitative analysis of the various hemodynamic parameters. (biomedcentral.com)
  • Therefore, we quantitatively analyzed various hemodynamic parameters related to the RV under normal, heart failure (HF), and HF incorporated with continuous flow LVAD therapy by using a computational model. (biomedcentral.com)
  • Simulation studies, on the other hand, can overcome those limitations and provide data on a variety of hemodynamic parameters in a noninvasive manner. (biomedcentral.com)
  • Model verification was performed by comparing the simulation output under baseline conditions and at different levels of orthostatic stress to sets of population-averaged hemodynamic data reported in the literature. (cellml.org)
  • Windkessel
  • We determined the impedance spectra at several cycle lengths for each embryo and a reference curve from a three-element Windkessel model with the use of nonlinear curve fitting. (ahajournals.org)
  • fluid
  • We propose a one-dimensional model for collecting lymphatics coupled with a novel Electro-Fluid-Mechanical Contraction (EFMC) model for dynamical contractions, based on a modified FitzHugh-Nagumo model for action potentials. (springer.com)
  • The EFMC model combines the electrical activity of lymphangions (action potentials) with fluid-mechanical feedback (circumferential stretch of the lymphatic wall and wall shear stress) and lymphatic vessel wall contractions. (springer.com)
  • Imaging
  • Conclusions: This new method offers a robust and time saving procedure to quantify myocardial tissue and blood with displacement, velocity and deformation parameters on regular sequences of CMR imaging. (jove.com)
  • differential
  • The EFMC model is governed by four Ordinary Differential Equations (ODEs) and phenomenologically relies on: (1) environmental calcium influx, (2) stretch-activated calcium influx, and (3) contraction inhibitions induced by wall shear stresses. (springer.com)
  • Models that use Partial Differential Equations. (physiome.org)
  • simulation
  • The goal of developing therapies and dosage regimes for characterized subgroups of the general population can be facilitated by the use of simulation models able to incorporate information about inter-individual variability in drug disposition (pharmacokinetics), toxicity and response effect (pharmacodynamics). (royalsocietypublishing.org)
  • ventricular
  • It causes and aggravates pre-existing AR while performing well in the event of mitral regurgitation (MR). Indirect parameters, such as the mean systolic pressure, product of heart rate and peak systolic pressure, and pressure-volume are used to quantify the effect of IABP on ventricular workload. (springer.com)
  • The goal of this study is to examine the effect of IABP therapy on ventricular mechanics under valvular insufficiency by using a computational model of the heart. (springer.com)
  • Indirect parameters such as the mean systolic pressure, product of heart rate and peak systolic pressure, and pressure-volume are used to quantify the effect of IABP on ventricular workload. (springer.com)
  • The goal of this study involves examining the effect of IABP therapy on ventricular mechanics under the valvular insufficiency condition, which includes the AR and MR conditions in the failing ventricle, by using a computational model of the heart. (springer.com)
  • To test this hypothesis, we used a computational model to explore the effects of heart rate (HR) and aortic rigidity on left ventricular (LV) power requirement. (jove.com)
  • Echocardiography is the mainstay of the noninvasive assessment of right ventricular function in rodent models and has the advantage of clear translation to humans in whom the same tool is used. (jove.com)
  • Left ventricular mass (LVM) is known to be related to overall and cardiovascular mortality in end stage kidney disease (ESKD) patients. (jove.com)
  • elasticity
  • In each segment, individual components are modelled by representations of the local resistance to blood flow, vessel elasticity and the inertia of the blood. (cellml.org)
  • time-dependent
  • The pumping heart is modeled by the time-dependent linear curves of compliances in the heart. (koreascience.or.kr)
  • In the current study, a large strain time-dependent constitutive model of human vocal fold tissue is used to investigate effects of phonatory posturing cyclic strain in the range of 1 Hz to 10 Hz. (jove.com)
  • Methods
  • Using the methods of grounded theory, our findings were synthesized into a theoretical model depicting the structure and process of formal family meetings within this setting. (jove.com)
  • Standard methods for parameter identification rely on gradient descent, which can often converge to wrong solutions, particularly as the number of parameters increases. (canterbury.ac.nz)
  • Overview of congenital and adult cardiovascular disease, diagnostic methods and treatment strategies. (stanford.edu)
  • Existing methods for studying voice production include in vivo experimentation using human and animal subjects, in vitro experimentation using excised larynges and synthetic models, and computational modeling. (jove.com)
  • elastance
  • The heart is modelled as a two-chambered pump with variable elastance and two heart valves to control the direction of blood flow. (cellml.org)
  • biological
  • This review outlines some of the challenges and opportunities for those engaged in modelling biological systems. (royalsocietypublishing.org)
  • From a control design perspective, the important issues from the PD model are the large variability in the observed responses, typical of biological systems, and the significant delay between the HR response and the infusion administration. (rpi.edu)
  • murine models
  • Published echocardiography protocols in murine models of PAH are lacking. (jove.com)
  • The use of primary cardiomyocytes (CMs) in culture has provided a powerful complement to murine models of heart disease in advancing our understanding of heart disease. (jove.com)
  • To elucidate mechanisms of renal injury due to ischemia and possible therapeutic strategies murine models are intensively required 7-13 . (jove.com)
  • Flow
  • This is the first model capable of estimating volumetric blood flow to the uterus via the utero-ovarian communicating arteries. (springer.com)
  • Using this model, blood flow has been simulated which show physiologically realistic flow profiles. (biomedcentral.com)
  • and provide the three-dimensional model and the fractional flow reserve to a user via a display device, wherein the three-dimensional model and the fractional flow reserve are displayed together on the display device. (patentsencyclopedia.com)
  • dysfunction
  • Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. (jove.com)
  • human
  • Through its efforts to standardize annotation with consequent increase in data usability, the human physiome project has a vital role in improving productivity in model development and, thus, the development of personalized therapy regimes. (royalsocietypublishing.org)
  • D*(t), and demonstrate in the healthy human brain that both parameters D* and fD* are significantly larger during systole than diastole, while the diffusion coefficient D and f do not vary significantly. (jove.com)
  • Consequently, one- and two-layer synthetic vocal fold models have exhibited disadvantages 3,6,8 such as higher onset pressures than what are typical for human phonation (onset pressure is the minimum lung pressure required to initiate vibration), unnaturally large inferior-superior motion, and lack of a "mucosal wave" (a vertically-traveling wave that is characteristic of healthy human vocal fold vibration). (jove.com)
  • Ethanol administration to pregnant rodents has been used to model human exposure during the first and second trimesters of pregnancy. (jove.com)
  • objective
  • Objective: Our purpose was to rigorously examine the nature of family meetings as conducted in an inpatient hospice care unit in order to generate an inductive theoretical model. (jove.com)
  • The objective is to use this modeled information to design a control device to read several patient outputs, and to adjust the dosage of several drugs accordingly. (rpi.edu)