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Heart Wall (heart + wall)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

The Use of Ultrasonic Reflectoscope for the Continuous Recording of the Movements of Heart Walls.

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 3 2004
I. Edler
First page of article [source]

Physiologically correct animation of the heart

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2008
Kyoungju Park
Abstract Physiologically correct animation of the heart should incorporate non-homogeneous and nonlinear motions of the heart. Therefore, we introduce a methodology that estimates deformations from volume images and utilizes them for animation. Since volume images are acquired at regular slicing intervals, they miss information between slices and recover deformation on the slices. Therefore, the estimated finite element models (FEMs) result in coarse meshes with chunk elements the sizes of which depend on the slice intervals. Thus, we introduce a method of generating a detailed model using implicit surfaces and transferring a deformation from a FEM to implicit surfaces. An implicit surface heart model is reconstructed using contour data points and then cross-parameterized to the heart FEM, the time-varying deformation of which has been estimated by tracking the insights of the heart wall. The implicit surface heart models are composed of four heart walls that are blended into one model. A correspondence map between the source and the target meshes is made using the template fitting method. Deformation coupling transfers the deformation of a coarse heart FEM model to a detailed implicit model by factorizing linear equations. We demonstrate the system and show the resulting deformation of an implicit heart model. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Prediction of the External Work of the Native Heart From the Dynamic H-Q Curves of the Rotary Blood Pumps During Left Heart Bypass

ARTIFICIAL ORGANS, Issue 9 2010
Yoshimasa Yokoyama
Abstract The ventricular performance is dependent on the drainage effect of rotary blood pumps (RBPs) and the performance of RBPs is affected by the ventricular pulsation. In this study, the interaction between the ventricle and RBPs was examined using the pressure-volume (P-V) diagram of the ventricle and dynamic head pressure-bypass flow (H-Q) curves (H, head pressure: arterial pressure minus ventricular pressure vs. Q, bypass flow) of the RBPs. We first investigated the relationships in a mock loop with a passive fill ventricle, followed by validation in ex vivo animal experiments. An apical drainage cannula with a micro-pressure sensor was especially fabricated to obtain ventricular pressure, while three pairs of ultrasonic crystals placed on the heart wall were used to derive ventricular volume. The mock loop-configured ventricular apical,descending aorta bypass revealed that the external work of the ventricle expressed by the area inside the P-V diagrams (EWHeart) correlated strongly with the area inside dynamic H-Q curves (EWVAD), with the coefficients of correlation being R2 = 0.869 , 0.961. The results in the mock loop were verified in the ex vivo studies using three Shiba goats (10,25 kg in body weight), showing the correlation coefficients of R2 = 0.802 , 0.817. The linear regression analysis indicated that the increase in the bypass flow reduced pulsatility in the ventricle expressed in EWHeart as well as in EWVAD. Experimental results, both mock loop and animal studies, showed that the interaction between cardiac external work and H-Q performance of RBPs can be expressed by the relationships "EWHeart versus EWVAD." The pulsatile nature of the native heart can be expressed in the area underneath the H-Q curves of RBPs EWVAD during left heart bypass indicating the status of the level of assistance by RBPs and the native heart function. [source]