Publications by authors named "J Sundnes"

The existing theories of post-traumatic stress disorder (PTSD) have inspired large volumes of research and have contributed substantially to our current knowledge base. However, most of the theories are of a qualitative and verbal nature, and may be difficult to evaluate and compare with each other. In this paper, we propose that one way forward is to use computational modelling to formulate more precise theories of PTSD that can be evaluated by (1) assessing whether the model can explain fundamental phenomena related to PTSD, and (2) comparing simulated outcomes with real data.

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Article Synopsis
  • - Atrial fibrillation (AF) increases the risk of stroke due to blood clot formation mainly in the left atrial appendage (LAA), and this study explores how different wall motion models affect risk assessment through computational fluid dynamics (CFD) simulations.
  • - Four modeling scenarios were tested: rigid walls, generic wall motion, semi-generic wall motion, and patient-specific wall motion, using a left atrial geometry obtained from 4D CT scans during AF.
  • - Results showed that while wall motion did not significantly impact hemodynamics or thrombus markers overall, rigid wall assumptions distorted flow patterns in the LAA, suggesting that more flexible models (generic or patient-specific) can provide more accurate risk evaluations. *
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Pulmonary arterial hypertension (PAH) presents a significant challenge to right ventricular (RV) function due to progressive pressure overload, necessitating adaptive remodeling in the form of increased wall thickness, enhanced myocardial contractility and stiffness to maintain cardiac performance. However, the impact of these remodeling mechanisms on RV mechanics in not clearly understood. In addition, there is a lack of quantitative understanding of how each mechanism individually influences RV mechanics.

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Background: Increasing cardiomyocyte contraction during myocardial stretch serves as the basis for the Frank-Starling mechanism in the heart. However, it remains unclear how this phenomenon occurs regionally within cardiomyocytes, at the level of individual sarcomeres. We investigated sarcomere contractile synchrony and how intersarcomere dynamics contribute to increasing contractility during cell lengthening.

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Computational fluid dynamics (CFD) in combination with patient-specific medical images has been used to correlate flow phenotypes with disease initiation, progression and outcome, in search of a prospective clinical tool. A large number of CFD software packages are available, but are typically based on rigid domains and low-order finite volume methods, and are often implemented in massive low-level C++ libraries. Furthermore, only a handful of solvers have been appropriately verified and validated for their intended use.

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