References of "Dauby, Pierre"
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See detailA multi-scale cardiovascular system model can account for the load-dependence of the end-systolic pressure-volume relationship.
Pironet, Antoine ULg; Desaive, Thomas ULg; Kosta, Sarah ULg et al

in BioMedical Engineering OnLine (2013), 12(1), 8

ABSTRACT: BACKGROUND: The end-systolic pressure-volume relationship is often considered as a load-independent property of the heart and, for this reason, is widely used as an index of ventricular ... [more ▼]

ABSTRACT: BACKGROUND: The end-systolic pressure-volume relationship is often considered as a load-independent property of the heart and, for this reason, is widely used as an index of ventricular contractility. However, many criticisms have been expressed against this index and the underlying time-varying elastance theory: first, it does not consider the phenomena underlying contraction and second, the end-systolic pressure volume relationship has been experimentally shown to be load-dependent. METHODS: In place of the time-varying elastance theory, a microscopic model of sarcomere contraction is used to infer the pressure generated by the contraction of the left ventricle, considered as a spherical assembling of sarcomere units. The left ventricle model is inserted into a closed-loop model of the cardiovascular system. Finally, parameters of the modified cardiovascular system model are identified to reproduce the hemodynamics of a normal dog. RESULTS: Experiments that have proven the limitations of the time-varying elastance theory are reproduced with our model: (1) preload reductions, (2) afterload increases, (3) the same experiments with increased ventricular contractility, (4) isovolumic contractions and (5) flow-clamps. All experiments simulated with the model generate different end-systolic pressure-volume relationships, showing that this relationship is actually load-dependent. Furthermore, we show that the results of our simulations are in good agreement with experiments. CONCLUSIONS: We implemented a multi-scale model of the cardiovascular system, in which ventricular contraction is described by a detailed sarcomere model. Using this model, we successfully reproduced a number of experiments that have shown the failing points of the time-varying elastance theory. In particular, the developed multi-scale model of the cardiovascular system can capture the load-dependence of the end-systolic pressure-volume relationship. [less ▲]

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See detailnon invasive estimation of left atrial pressure and mitral valve area waveforms during an entire cardiac cycle
Paeme, Sabine ULg; Pironet, Antoine ULg; LANCELLOTTI, Patrizio ULg et al

in proceeding of 11th national day of the National Committee on Biomedical Engineering (2012, December 07)

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See detailDirect parameter identification in a model of the cardiovascular system
Pironet, Antoine ULg; Dauby, Pierre ULg; Desaive, Thomas ULg

in 11th Belgian Day on Biomedical Engineering (2012, December 07)

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See detailThe rabbit left ventricle modeling at the cellular scale: application to flow-clamp experiments
Kosta, Sarah ULg; Pironet, Antoine ULg; Dauby, Pierre ULg

in Proceedings of the 11th Belgian National Day on Biomedical Engineering (2012, December)

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See detailDevelopment and Identification of a Closed-Loop Model of the Cardiovascular System Including the Atria
Pironet, Antoine ULg; Revie, James A.; Paeme, Sabine ULg et al

Conference (2012, August 31)

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See detailStructural model of the mitral valve included in a cardiovascular closed loop model. Static and dynamic validation
Paeme, Sabine ULg; Pironet, Antoine ULg; Chase, J. Geoffrey et al

in proceedings of 8th IFAC Symposium on Biological and Medical Systems, Budapest 29-31 août 2012 (2012, August 31)

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See detailAutonomous electrical activity induced by cardiac tissue deformation in a thermo-electro-mechanical background
Collet, Arnaud ULg; Desaive, Thomas ULg; Dauby, Pierre ULg

in 8th IFAC Symposium on Biological and Medical Systems (2012, August)

In a healthy heart, the mechano-electric feedback (MEF) process acts as an intrinsic regulatory mechanism of the myocardium which allows the normal cardiac contraction by damping mechanical perturbations ... [more ▼]

In a healthy heart, the mechano-electric feedback (MEF) process acts as an intrinsic regulatory mechanism of the myocardium which allows the normal cardiac contraction by damping mechanical perturbations in order to generate a new healthy electromechanical situation. However, under certain conditions, the MEF can be a generator of dramatic arrhythmias by inducing local electrical depolarizations as a result of abnormal cardiac tissue deformations, via stretch-activated channels (SACs). Then, these perturbations can propagate in the whole heart and lead to global cardiac dysfunctions. In the present study, we examine the spatio-temporal behavior of the autonomous electrical activity induced by the MEF when the heart is subject to temperature variations. For instance, such a situation can occur during a therapeutic hypothermia. This technique is usually used to prevent neuronal injuries after a cardiac resuscitation. From this perspective, we introduce a one-dimensional time-dependent model containing all the key ingredients that allow accounting for excitation-contraction coupling, MEF and thermoelectric coupling. Our simulations show that an autonomous electrical activity can be induced by cardiac deformations, but only inside a certain temperature interval. In addition, in some cases, the autonomous electrical activity takes place in a periodic way like a pacemaker. We also highlight that some properties of the action potentials that are generated by the MEF, are significantly influenced by temperature. Moreover, in the situation where a pacemaker activity occurs, we also show that the period is heavily temperature-dependent. [less ▲]

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See detailDevelopment and Identification of a Closed-Loop Model of the Cardiovascular System Including the Atria
Pironet, Antoine ULg; Revie, James A.; Paeme, Sabine ULg et al

in Proceedings of the 8th IFAC Symposium on Biological and Medical Systems (2012, August)

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See detailEvaporation in motion
Machrafi, Hatim ULg; Rednikov, Alexey; Colinet, Pierre et al

Article for general public (2012)

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See detailSolutal Marangoni instability in a binary liquid layer evaporating into air: the importance of transients in the gas for highly unstable cases
Machrafi, Hatim ULg; Rednikov, Alexey; Colinet, Pierre et al

in Bulletin of the American Physical Society, Vol. 57, n°17 (2012) (2012)

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See detailBeyond the Fourier heat conduction law and the thermal no-slip boundary condition
Lebon, Georgy ULg; Jou, D.; Dauby, Pierre ULg

in Physics Letters A (2012), 376(45), 2842-2846

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See detailSolutal Marangoni instability of binary mixtures evaporating into air: an analytical model describing highly unstable cases
Machrafi, Hatim ULg; Rednikov, Alexey; Colinet, Pierre et al

in Book of abstracts of the Seventh International Symposium on TWO-PHASE SYSTEMS FOR GROUND AND SPACE APPLICATIONS (2012)

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See detailExtremely Unstable Evaporative Bénard-Marangoni Systems: the Role of Transients in the Gas
Rednikov, Alexey; Machrafi, Hatim ULg; Dauby, Pierre ULg et al

in Book of Conference Abstracts of the International Marangoni Association, 6 (2012)

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See detailOnset of thermal ripples at the interface of an evaporating liquid under a flow of inert gas
Scheid, B.; Margerit, J.; Iorio, C. S. et al

in Experiments in Fluids (2012), 52

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See detailModèle unidimensionnel instationnaire de l'activité pacemaker cardiaque induite par le feedback mécano-électrique dans un environnement thermo-électro-mécanique
Collet, Arnaud ULg; Desaive, Thomas ULg; Dauby, Pierre ULg

in Annales de Cardiologie et d'Angeiologie (2012)

Aim of the study: In a healthy heart, the mechano-electric feedback (MEF) process acts as an intrinsic regulatory mechanism of the myocardium which allows the normal cardiac contraction by damping ... [more ▼]

Aim of the study: In a healthy heart, the mechano-electric feedback (MEF) process acts as an intrinsic regulatory mechanism of the myocardium which allows the normal cardiac contraction by damping mechanical perturbations in order to generate a new healthy electromechanical situation. However, under certain conditions, the MEF can be a generator of dramatic arrhythmias by inducing local electrical depolarizations as a result of abnormal cardiac tissue deformations, via stretch-activated channels (SACs). Then, these perturbations can propagate in the whole heart and lead to global cardiac dysfunctions. In the present study, we qualitatively investigate the influence of temperature on autonomous electrical activity generated by the MEF. Method: We introduce a one-dimensional time-dependent model containing all the key ingredients that allow accounting for the excitation-contraction coupling, the MEF and the thermoelectric coupling. Results: Our simulations show that an autonomous electrical activity can be induced by cardiac deformations, but only inside a certain temperature interval. In addition, in some cases, the autonomous electrical activity takes place in a periodic way like a pacemaker. We also highlight that some properties of action potentials, generated by the mechano-electric feedback, are significantly influenced by temperature. Moreover, in the situation where a pacemaker activity occurs, we also show that the period is heavily temperature-dependent. Conclusions: Our qualitative model shows that the temperature is a significant factor with regards to the electromechanical behavior of the heart and more specifically, with regards to the autonomous electrical activity induced by the cardiac tissue deformations. [less ▲]

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