Computational cardiac models have been extensively used to study different cardiac biomechanics; specifically, finite-element analysis has been one of the tools used to study the internal stresses and strains in the cardiac wall during the cardiac cycle. Cubic-Hermite finite element meshes have been used for simulating cardiac biomechanics due to their convergence characteristics and their ability to capture smooth geometries compactly-fewer elements are needed to build the cardiac geometry-compared to linear tetrahedral meshes. Such meshes have previously been used only with simple ventricular geometries with non-physiological boundary conditions due to challenges associated with creating cubic-Hermite meshes of the complex heart geometry. However, it is critical to accurately capture the different geometric characteristics of the heart and apply physiologically equivalent boundary conditions to replicate the in vivo heart motion. In this work, we created a four-chamber cardiac model utilizing cubic-Hermite elements and simulated a full cardiac cycle by coupling the 3D finite element model with a lumped circulation model. The myocardial fiber-orientations were interpolated within the mesh using the Log-Euclidean method to overcome the singularity associated with interpolation of orthogonal matrices. Physiologically equivalent rigid body constraints were applied to the nodes along the valve plane and the accuracy of the resulting simulations were validated using open source clinical data. We then simulated a complete cardiac cycle of a healthy heart and a heart with acute myocardial infarction. We compared the pumping functionality of the heart for both cases by calculating the ventricular work. We observed a 20% reduction in acute work done by the heart immediately after myocardial infarction. The myocardial wall displacements obtained from the four-chamber model are comparable to actual patient data, without requiring complicated non-physiological boundary conditions usually required in truncated ventricular heart models.
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http://dx.doi.org/10.1016/j.jbiomech.2019.05.019 | DOI Listing |
Med Phys
December 2024
Image X Institute, University of Sydney, Sydney, New South Wales, Australia.
Background: STereotactic Arrhythmia Radioablation (STAR) is a novel noninvasive method for treating arrythmias in which external beam radiation is directed towards subregions of the heart. Challenges for accurate STAR targeting include small target volumes and relatively large patient motion, which can lead to radiation related patient toxicities. 4D Cone-beam CT (CBCT) images are used for stereotactic lung treatments to account for respiration-related patient motion.
View Article and Find Full Text PDFJ Vis Exp
December 2024
School of Biological Science and Medical Engineering, Southeast University; Mathematical Sciences Department, Worcester Polytechnic Institute.
Quantifying the mechanical properties of coronary arterial walls could provide meaningful information for the diagnosis, management, and treatment of coronary artery diseases. Since patient-specific coronary samples are not available for patients requiring continuous monitoring, direct experimental testing of vessel material properties becomes impossible. Current coronary models typically use material parameters from available literature, leading to significant mechanical stress/strain calculation errors.
View Article and Find Full Text PDFInt J Cardiol Congenit Heart Dis
December 2024
Department of Cardiology, Boston Children's Hospital, Boston, MA, USA.
Background: Change in the oxygen consumption (VO) at the ventilatory anaerobic threshold (VAT) is an important outcome in research studies of children with congenital heart disease (CHD). The range of values reported by different raters for any given VAT is needed to contextualize a change in VAT in intervention studies.
Methods: Sixty maximal cardiopulmonary exercise tests (CPET) for CHD patients 8-21 years old were independently reviewed by six exercise physiologists and four pediatric cardiologists.
Comput Biol Med
December 2024
Department of Mechanical and Aerospace Engineering, University of Central Florida, and the Biomedical Acoustics Research Company, 32816, Orlando, FL, USA.
Background: Seismocardiographic signals (SCG) are chest wall vibrations induced by mechanical cardiac activities. This study investigated the morphological changes in the SCG signal due to respiration and exercise.
Methods: Fifteen healthy subjects were recruited, and SCG was acquired before and after exercise.
Comput Methods Programs Biomed
December 2024
Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain. Electronic address:
Background And Objective: In silico human models are being used more and more to predict the potential proarrhythmic risk of compounds. It has been shown that incorporation of the dynamics of drug-hERG channel interactions can have an important impact on the action potential duration (APD) at normal heart rates. Our aim is to investigate the relevance of drug dynamics on other important biomarkers of proarrhythmic risk.
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