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The objective of this study was to simulate clamping of the aorta. It is computationally demanding and involves contact between clamp and aorta, large deformations, and fluid-structure interactions (FSI). Models of the aortic root and clamp were created and solve in ADINA, a finite element analysis package. The tissue model was created using a non-linear material. Fluid-structure interactions (FSI)...
We built a pulmonary and cardiovascular integrated model which is driven by O2 consumption. The integrated model consists of a pulmonary model, a cardiovascular model, a gas exchange model, a respiratory control system model and a cardiovascular control model. To verify the integrated model, we calculated ventilations and cardiac outputs in different O2 consumptions and compared the results with literature...
Nowadays, circulatory support has become a common practice in medicine and a standard in the treatments of cardio vascular disease (CVD). A new pneumatic ventricular assist device (VAD) has been developed in Mexico City. This paper shows the first results of acute in-vivo trials, intended to verify the new system for providing physiological flows and pressures. Two VADs were implanted to as right...
Current implantable LVADs are bulky and expensive. They all require high-risk surgery for insertion including a need for a heart/lung machine and complex connection to the heart or major blood vessels. This paper presents a newly designed "plug and play" transventricle LVAD that can be plugged into the circulation easily and work instantly with no complicated surgical procedure, no prime,...
In the development of left ventricular assist devices (LVADs), numerical simulations of the cardiovascular (CV) system have been widely used. Further, electrohydraulic simulations have been developed to evaluate the performance of a physical LVAD prototype against a numerical model of the CV system. The effects of dynamic cardiac compression (DCC) have been less well modeled. This paper considers...
Wave propagation through the arterial system changes with age and disease state, and mutant mice are often used to study these conditions. We have developed several noninvasive ultrasonic techniques to measure blood velocity and vessel wall motion from which we can calculate aortic pulse wave velocity (PWV), local compliance, impedance spectra, characteristic impedance (Zc), augmentation index (AI),...
Dwarf mouse (deficient in growth hormone and insulin-like growth factor-1) lives about 30% longer than wild type mice. However, very little is known about their cardiovascular physiology. We examined the aortic input impedance in dwarf mice and their wild-type littermates to evaluate any differences. Aortic impedance was determined using pressure and velocity signals which are independent of body...
Idealized geometries of bypass grafts have been constructed to analyze the blood flow in an aorto-coronary bypass graft system. In this paper we discuss the influence of the realistic bypass graft geometry for the in-plane and out-of-plane aorto-left bypass graft models on the wall shear stress distribution. In the in-plane aorto-left coronary bypass graft model we have the centerlines of the aorta,...
Sleep studies are considered a paradigmatic example of the complex cardiorespiratory interactions, with an important impact also for clinical implications: diagnosis and treatment control, not only for the classical common sleep disturbances, but also for obstructive sleep apnea (OSA) or central apnea (CA) which are often associated with an increased risk of cardiovascular pathologies, such as hypertension,...
To investigate the effects of voluntary breathing on respiratory sinus arrhythmia and nonlinearity of heart rate variability (HRV), two kinds of voluntary breathing, speech and breath-holding, were used. The results showed that both types of voluntary breathing diminished the high frequency component of HRV, but speech decreased, while breath-holding enhanced the nonlinearity of HRV as detected by...
Studies suggest that obstructive sleep apnea syndrome (OSAS) is causally related to abnormal cardiovascular autonomic control in adults, but this has not been established in pediatric OSAS. The goal of this study was to quantify autonomic system dysfunction, as manifested by cardiovascular response abnormalities, in children with OSAS. During wakefulness, we continuously measured the ECG, arterial...
The risk for cardiovascular disease is significantly high in diabetes mellitus. Experimental evidence suggests that oxidative stress plays a dominant role in the pathogenesis of diabetes mellitus. Carvedilol, a non-selective beta-adrenoceptor and selective alpha1-adrenoceptor blocker, also has antioxidant and free radical scavenger properties. In the present study the effect of carvedilol on the antioxidative...
The aim of the present study was to clarify whether simulated microgravity-induced post-suspension cardiovascular deconditioning in rats could be prevented by daily short-duration standing (STD). Three groups of rats were used as subjects to perform the experiments. Compared to a control group of male Sprague-Dawley rats (CON), a group of rats with tail-suspension (SUS) for 28 d was used to simulate...
The main purpose of this paper is to develop a theoretical tool in order to fundamentally characterize the performance of Myocardial elastography and identify the optimal parameters to be used for the more reliable detection of ischemia or infarction. A complete representation of the left-ventricular function throughout an entire cardiac cycle was previously demonstrated through the use of a 3D finite-element...
This paper proposes to use the pulse transit time variability (PTTV) as an indicator of the variability in hemodynamics and studies its correlation with other cardiovascular variabilities, especially the blood pressure variability (BPV), which receives increasing attentions as an independent indicator of autonomic regulation and abnormalities in cardiovascular system. Continuous blood pressure (BP),...
Shape design optimization for an untethered microdevice meant to navigate in the human bloodstream is studied based on previous variational finite element (FE) work done. The suggested shape for a first generation prototype is a prolate spheroid design, which enables to minimize the drag force and to maximize the use of the MRI's magnetic gradients
This paper presents a new technique for identification of regional dysfunctions in the left ventricle from 2-D echocardiography. It uses a novel left ventricular border tracking algorithm based on fuzzy inference system. In this paper we show how the regional dysfunction present in the left ventricle can be identified by tracking the movement of centre of mass of left ventricle in a 2D space. The...
[Gd(TTDA-BOM)]2- is a newly developed paramagnetic contrast agent. The ligand, TTDA-BOM, bears a benzyloxymethyl group so that the lipophilicity is increased. The water exchange rate for [Gd(TTDA-BOM)]2- is significantly higher than that of [Gd(DTPA)]2- and [Gd(BOPTA)]2-. In addition, the bound relaxivity of this Gd (III) complex has a remarkably high value with HSA. Therefore, it has potential to...
Non-invasive cardiovascular measurements are used to evaluate cardiovascular diseases early and to cure early. By using various evaluation methods of cardiovascular features to diagnose cardiovascular disease. Flow-mediated dilation (FMD) evaluated by ultrasound offers a mechanism to characterize endothelial function and, therefore, may play a role in the diagnosis of cardiovascular diseases. Cardiovascular...
Echocardiography is a routine clinical procedure to diagnose cardiac functions. The organic structure of the mouse is similar to that of human so that murine echocardiography has potentially become an effective tool for the assessment of human cardiovascular disease. However, clinical ultrasonic imaging systems are not suitable for murine cardiac imaging due to its limited spatial and temporal resolution...
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