scholarly journals Improved estimation of left ventricular volume from electric field modeling

2021 ◽  
Vol 12 (1) ◽  
pp. 125-134
Author(s):  
Leonie Korn ◽  
Stephan Dahlmanns ◽  
Steffen Leonhardt ◽  
Marian Walter
Keyword(s):  
Electric Field ◽  
Analytical Calculation ◽  
Ventricular Volume ◽  
Volume Measurement ◽  
In Vitro Models ◽  
Left Ventricular ◽  
Calculation Methods ◽  
Ventricular Assist ◽  
Wide Range

Abstract Volume measurement is beneficial in left ventricular assist device (LVAD) therapy to quantify patient demand. In principle, an LVAD could provide a platform that allows bioimpedance measurements inside the ventricle without requiring additional implants. Conductance measured by the LVAD can then be used to estimate the ventricular radius, which can be applied to calculate ventricular volume. However, established methods that estimate radius from conductance require elaborate individual calibration or show low accuracy. This study presents two analytical calculation methods to estimate left ventricular radius from conductance using electric field theory. These methods build on the established method of Wei, now considering the dielectric properties of muscle and background tissue, the refraction of the electric field at the blood-muscle boundary, and the changes of the electric field caused by the measurements. The methods are validated in five glass containers of different radius. Additional bioimpedance measurements are performed in in-vitro models that replicate the left ventricle’s shape and conductive properties. The proposed analytical calculation methods estimate the radii of the containers and the in-vitro models with higher accuracy and precision than Wei’s method. The lead method performs excellently in glass cylinders over a wide range of radii (bias: 1.66%–2.48%, limits of agreement < 16.33%) without calibration to specific geometries.

Resizable Ventricular Patch Plasty in the Porcine Left Ventricle a Pilot Study

2010 ◽  
Vol 5 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Willemijn H. F. Huijgen ◽  
Paul F. Gründeman ◽  
Tycho van der Spoel ◽  
Maarten-Jan Cramer ◽  
Paul Steendijk ◽  
...  
Keyword(s):  
Pilot Study ◽  
Animal Experiments ◽  
Ventricular Volume ◽  
Left Ventricular ◽  
Left Ventricular Aneurysm ◽  
Patch Shape ◽  
End Diastolic Volume ◽  
Patch Plasty

Objective Endoventricular circular patch plasty is a method used to reconstruct the ventricular cavity in patients with (post) ischemic left ventricular aneurysm or global dilatation. However, late redilatation with mitral regurgitation has been reported, in which postoperative apex shape seems to play an important role. We studied the feasibility of ventricular volume downsizing with a variably shaped patch in porcine hearts. Methods In five in vitro and two acute animal experiments, a dyskinetic aneurysm was simulated with a pericardial insert. Reducing patch surface by changing patch shape diminished end-diastolic volume. In vitro, static end-diastolic volume was determined for each patch shape using volumetry and echocardiography. In the acute animal experiments, preliminary observations of patch behavior in live material were made, and pressure/time relationship, dPdTmax, was registered. Results In vitro, bringing the convex patch into a flat plane reduced LV volume from 66 ± 7 mL (aneurysm) to 49 ± 5 mL. Four of 5 patch shapes further reduced volume to a mean of 38 ± 7 mL (P = 0.03). The in vitro echocardiographic measurements correlated with volumetry findings (r = 0.81). In the acute animal experiments, dPdTmax varied with patch shape, independent of volume changes. Conclusions In this pilot study, in vitro shape configuration of the resizable ventricular patch resulted in a calibrated end-diastolic volume reduction. The data of the two in vivo pilot experiments clearly indicate that change in patch configuration in the situation of more or less unchanged end-diastolic volume had impact on cardiac performance. Future studies must substantiate the results of this observation.

scholarly journals Validation of a CFD Methodology for Positive Displacement LVAD Analysis Using PIV Data

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Richard B. Medvitz ◽  
Varun Reddy ◽  
Steve Deutsch ◽  
Keefe B. Manning ◽  
Eric G. Paterson
Keyword(s):  
Left Ventricular ◽  
Hydrodynamic Performance ◽  
Ventricular Assist ◽  
Shear Rates ◽  
Eddy Simulation ◽  
Positive Displacement ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd ◽  
High Level

Computational fluid dynamics (CFD) is used to asses the hydrodynamic performance of a positive displacement left ventricular assist device. The computational model uses implicit large eddy simulation direct resolution of the chamber compression and modeled valve closure to reproduce the in vitro results. The computations are validated through comparisons with experimental particle image velocimetry (PIV) data. Qualitative comparisons of flow patterns, velocity fields, and wall-shear rates demonstrate a high level of agreement between the computations and experiments. Quantitatively, the PIV and CFD show similar probed velocity histories, closely matching jet velocities and comparable wall-strain rates. Overall, it has been shown that CFD can provide detailed flow field and wall-strain rate data, which is important in evaluating blood pump performance.

scholarly journals In vitro comparison of the hemocompatibility of two centrifugal left ventricular assist devices

2019 ◽  
Vol 157 (2) ◽  
pp. 591-599.e4 ◽  
Author(s):  
Rashad Zayat ◽  
Ajay Moza ◽  
Oliver Grottke ◽  
Tim Grzanna ◽  
Tamara Fechter ◽  
...  
Keyword(s):  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist ◽  
In Vitro Comparison

A Systemic Mock Circulation for In-Vitro Testing of a Pneumatically Operated Left Ventricular Assist Device

2014 ◽  
Vol 47 (3) ◽  
pp. 8409-8414 ◽  
Author(s):  
A. Karabegovic ◽  
M. Hinteregger ◽  
C. Janeczek ◽  
W. Reichenfelser ◽  
V. Soragnese ◽  
...  
Keyword(s):  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Left Ventricular ◽  
In Vitro Testing ◽  
Assist Device ◽  
Ventricular Assist ◽  
Mock Circulation ◽  
Left Ventricular Assist

Defibrillator-Heart Pump: An Implantable Ventricular Assist Device With Integrated Defibrillator Component—The First In Vitro Testing

2019 ◽  
Vol 26 (6) ◽  
pp. 720-724
Author(s):  
Anas Aboud ◽  
Kai Liebing ◽  
Charlie Abraham ◽  
Jan-Christian Reil ◽  
Yara Turkistani ◽  
...  
Keyword(s):  
Heart Failure ◽  
Therapeutic Option ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
In Vitro Testing ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Heart Pump ◽  
Increased Risk

Left ventricular assist devices (LVADs) are an important therapeutic option for patients with end-stage heart failure waiting for heart transplantation or in older patients as definite therapy for heart failure. Interestingly, about 62% of patients receiving LVADs do not have an automatic implantable cardioverter-defibrillator (AICD) at the time of implantation, although these patients have increased risk of being confronted with dangerous arrhythmia. Therefore, an LVAD system including AICD function is a reasonable alternative for such heart failure patients thereby avoiding a second surgical intervention for AICD implantation. In this article, a newly developed system including LVAD and AICD function is introduced, and we also report its first in vitro testing.

scholarly journals Antioxidant and Anti-Inflammatory Effects of Citrus Flavonoid Hesperetin: Special Focus on Neurological Disorders

Antioxidants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 609 ◽  
Author(s):  
Amjad Khan ◽  
Muhammad Ikram ◽  
Jong Ryeal Hahm ◽  
Myeong Ok Kim
Keyword(s):  
Neurodegenerative Disorders ◽  
In Vitro Models ◽  
Experimental Models ◽  
Special Focus ◽  
Neuroprotective Effects ◽  
Beneficial Effects ◽  
Wide Range ◽  
Underlying Mechanisms

Neurodegenerative disorders have emerged as a serious health issue in the current era. The most common neurodegenerative disorders are Alzheimer’s disease (AD), Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis (ALS). These diseases involve progressive impairment of neurodegeneration and memory impairment. A wide range of compounds have been identified as potential neuroprotective agents against different models of neurodegeneration both in vivo and in vitro. Hesperetin, a flavanone class of citrus flavonoid, is a derivative of hesperidin found in citrus fruits such as oranges, grapes, and lemons. It has been extensively reported that hesperetin exerts neuroprotective effects in experimental models of neurodegenerative diseases. In this systematic review, we have compiled all the studies conducted on hesperetin in both in vivo and in vitro models of neurodegeneration. Here, we have used an approach to lessen the bias in each study, providing a least biased, broad understanding of findings and impartial conclusions of the strength of evidence and the reliability of findings. In this review, we collected different papers from a wide range of journals describing the beneficial effects of hesperetin on animal models of neurodegeneration. Our results demonstrated consistent neuroprotective effects of hesperetin against different models of neurodegeneration. In addition, we have summarized its underlying mechanisms. This study provides the foundations for future studies and recommendations of further mechanistic approaches to conduct preclinical studies on hesperetin in different models.

Accuracy of ventricular lumen volume measurement by intraventricular balloon method

1979 ◽  
Vol 236 (3) ◽  
pp. H506-H507 ◽  
Author(s):  
H. Suga ◽  
K. Sagawa
Keyword(s):  
Left Ventricular Volume ◽  
Ventricular Volume ◽  
Volume Measurement ◽  
Left Ventricular ◽  
Inflated Balloon ◽  
Lumen Volume ◽  
Formalin Fixed

To assess the accuracy of left ventricular volume measured by the intraventricular balloon method, we measured the space between the endocardium and the gradually inflated balloon in six Formalin-fixed canine left ventricles. The space was as small as 1-1.5 ml for intraballoon pressure of 100-200 mmHg and tended to increase to 2 ml with decreases in pressure to 50 mmHg.

In vitro performance of trans‐valve left ventricular assist device installed at aortic valve position

2020 ◽  
Vol 44 (10) ◽  
pp. 1067-1072
Author(s):  
Eiji Okamoto ◽  
Tetsuya Yano ◽  
Yusuke Inoue ◽  
Yasuyuki Shiraishi ◽  
Tomoyuki Yambe ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Left Ventricular ◽  
Assist Device ◽  
Ventricular Assist ◽  
Left Ventricular Assist ◽  
Valve Position ◽  
In Vitro Performance
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