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106 results on '"Colli Franzone, Piero"'

2. Transmural APD heterogeneity determines ventricular arrhythmogenesis in LQT8 syndrome: Insights from Bidomain computational modeling.

Author

Scacchi, Simone, Pavarino, Luca F., Mazzanti, Andrea, Trancuccio, Alessandro, Priori, Silvia G., and Colli Franzone, Piero

Subjects
VENTRICULAR arrhythmia, LONG QT syndrome, ARRHYTHMIA, ACTION potentials, VENTRICULAR tachycardia, HETEROGENEITY, HETEROZYGOSITY
Abstract

Long QT Syndrome type 8 (LQT8) is a cardiac arrhythmic disorder associated with Timothy Syndrome, stemming from mutations in the CACNA1C gene, particularly the G406R mutation. While prior studies hint at CACNA1C mutations' role in ventricular arrhythmia genesis, the mechanisms, especially in G406R presence, are not fully understood. This computational study explores how the G406R mutation, causing increased transmural dispersion of repolarization, induces and sustains reentrant ventricular arrhythmias. Using three-dimensional numerical simulations on an idealized left-ventricular model, integrating the Bidomain equations with the ten Tusscher-Panfilov ionic model, we observe that G406R mutation with 11% and 50% heterozygosis significantly increases transmural dispersion of repolarization. During S1-S4 stimulation protocols, these gradients facilitate conduction blocks, triggering reentrant ventricular tachycardia. Sustained reentry pathways occur only with G406R mutation at 50% heterozygosis, while neglecting transmural heterogeneities of action potential duration prevents stable reentry, regardless of G406R mutation presence. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Relationship Between Cardiac Electrical and Mechanical Activation Markers by Coupling Bidomain and Deformation Models

Author

Colli-Franzone, Piero, Pavarino, Luca F., Scacchi, Simone, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, van Assen, Hans, editor, Bovendeerd, Peter, editor, and Delhaas, Tammo, editor

Published
2015
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6. Parallel Coupled and Uncoupled Multilevel Solvers for the Bidomain Model of Electrocardiology

Author

Colli Franzone, Piero, Pavarino, Luca F., Scacchi, Simone, Barth, Timothy J., Series editor, Griebel, Michael, Series editor, Keyes, David E., Series editor, Nieminen, Risto M., Series editor, Roose, Dirk, Series editor, Schlick, Tamar, Series editor, Erhel, Jocelyne, editor, Gander, Martin J., editor, Halpern, Laurence, editor, Pichot, Géraldine, editor, Sassi, Taoufik, editor, and Widlund, Olof, editor

Published
2014
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7. Effects of Anodal Cardiac Stimulation on V m and Distributions: A Bidomain Study

Author

Colli-Franzone, Piero, Pavarino, Luca F., Scacchi, Simone, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Ourselin, Sébastien, editor, Rueckert, Daniel, editor, and Smith, Nicolas, editor

Published
2013
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9. Anode Make and Break Excitation Mechanisms and Strength-Interval Curves: Bidomain Simulations in 3D Rotational Anisotropy

Author

Colli-Franzone, Piero, Pavarino, Luca F., Scacchi, Simone, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Metaxas, Dimitris N., editor, and Axel, Leon, editor

Published
2011
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10. Effects of Anisotropy and Transmural Heterogeneity on the T-Wave Polarity of Simulated Electrograms

Author

Colli Franzone, Piero, Pavarino, Luca F., Scacchi, Simone, Taccardi, Bruno, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Ayache, Nicholas, editor, Delingette, Hervé, editor, and Sermesant, Maxime, editor

Published
2009
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19. Numerical evaluation of cardiac mechanical markers as estimators of the electrical activation time.

Author

Colli Franzone, Piero, Pavarino, Luca F., and Scacchi, Simone

Subjects
*SPATIAL resolution, *PSYCHOLOGICAL feedback, *ENERGY function, *STRAIN energy, *CARDIAC imaging, *ARRHYTHMIA
Abstract

Recent advances in the development of noninvasive cardiac imaging technologies have made it possible to measure longitudinal and circumferential strains at a high spatial resolution also at intramural level. Local mechanical activation times derived from these strains can be used as noninvasive estimates of electrical activation, in order to determine, eg, the origin of premature ectopic beats during focal arrhythmias or the pathway of reentrant circuits. The aim of this work is to assess the reliability of mechanical activation time markers derived from longitudinal and circumferential strains, denoted by ATell and ATecc, respectively, by means of three‐dimensional cardiac electromechanical simulations. These markers are compared against the electrical activation time (ATv), computed from the action potential waveform, and the reference mechanical activation markers derived from the active tension and fiber strain waveforms, denoted by ATta and ATeff, respectively. Our numerical simulations are based on a strongly coupled electromechanical model, including bidomain representation of the cardiac tissue, mechanoelectric (ie, stretch‐activated channels) and geometric feedbacks, transversely isotropic strain energy function for the description of passive mechanics and detailed membrane and excitation‐contraction coupling models. The results have shown that, during endocardial and epicardial ectopic stimulations, all the mechanical markers considered are highly correlated with ATv, exhibiting correlation coefficients larger than 0.8. However, during multiple endocardial stimulations, mimicking the ventricular sinus rhythm, the mechanical markers are less correlated with the electrical activation time, because of the more complex resulting excitation sequence. Moreover, the inspection of the endocardial and epicardial isochrones has shown that the ATell and ATecc mechanical activation sequences reproduce only some qualitative features of the electrical activation sequence, such as the areas of early and late activation, but in some cases, they might yield wrong excitation sources and significantly different isochrones patterns. Cardiac mechanical activation times derived from longitudinal or circumferential strains can be used as noninvasive estimates of electrical activation, with the aim of identifying, eg, the origin of premature ectopic beats during focal arrhythmias or the pathway of reentrant circuits. The aim of this work is to assess the reliability of mechanical activation time markers by means of three‐dimensional cardiac electromechanical simulations. The results have shown that the mechanical activation sequences reproduce the same qualitative features of the electrical activation sequence, with the same location of areas of early and late activation. [ABSTRACT FROM AUTHOR]

Published
2021
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21. Cardiac kinematic parameters computed from video of in situ beating heart

Author

Fassina, Lorenzo, primary, Rozzi, Giacomo, additional, Rossi, Stefano, additional, Scacchi, Simone, additional, Galetti, Maricla, additional, Lo Muzio, Francesco Paolo, additional, Del Bianco, Fabrizio, additional, Colli Franzone, Piero, additional, Petrilli, Giuseppe, additional, Faggian, Giuseppe, additional, and Miragoli, Michele, additional

Published
2017
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30. Convergence of front propagation for anisotropic bistable reaction-diffusion equations

Author

Paolini, Maurizio, Colli Franzone, Piero, Bellettini, Giovanni, Paolini, Maurizio (ORCID:0000-0001-9703-5813), Paolini, Maurizio, Colli Franzone, Piero, Bellettini, Giovanni, and Paolini, Maurizio (ORCID:0000-0001-9703-5813)

Abstract

We study the convergence of the singularly perturbed anisotropic, nonhomogeneous reaction-diffusion equation $\epsilon \partial_t u - \epsilon^2\text{div} T^o(x, \nabla u) + f(u) - \epsilon \frac{c_1}{c_0} g = 0$ where f is the derivative of a bistable quartic-like potential with unequal wells, $T^o (x, \cdot)$ is a nonlinear monotone operator homogeneous of degree one and g is a given forcing term. More precisely we prove that an appropriate level set of the solution satisfies an $O (\epsilon^3 |\log\epsilon|^2)$ error bound (in the Hausdorff distance) with respect to a hypersurface moving with the geometric law $V = (c - \epsilon \kappa_\phi) n_\phi +$ g-dependent terms, where $n_\phi$ is the so-called Cahn-Hoffmann vector and $\kappa_\phi$ denotes the anisotropic mean curvature of the hypersurface. We also discuss the connection between the anisotropic reaction-diffusion equation and the bidomain model, which is described by a system of equations modeling the propagation of an electric stimulus in the cardiac tissue.

Published
1997

35. DYNAMICAL EFFECTS OF MYOCARDIAL ISCHEMIA IN ANISOTROPIC CARDIAC MODELS IN THREE DIMENSIONS.

Author

COLLI FRANZONE, PIERO, PAVARINO, LUCA F., and SCACCHI, SIMONE

Subjects
*CORONARY disease, *MATHEMATICAL models, *MYOCARDIUM, *COMPUTER simulation, *ELECTROCARDIOGRAPHY
Abstract

The interaction between the presence of moderate or severe subendocardial ischemic regions and the anisotropic structure of the cardiac muscle is investigated here by means of numerical simulations based on anisotropic Bidomain and Monodomain models. The ischemic effects on cardiac excitation, recovery and distribution of action potential duration are discussed, showing the presence of ischemic epicardial markers. Extracellular potential distributions during the ST and TQ intervals are computed separately using non-stationary models. During the ST interval, the extracellular potential patterns differ from those simulated with stationary models used in the literature. These differences are explained by decomposing the cardiac current sources into conormal, axial and orthogonal components and by determining which component is dominant during the ST and TQ intervals. [ABSTRACT FROM AUTHOR]

Published
2007
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37. Accurate Computation of Electrograms in the Left Ventricular Wall.

Author

Colli-Franzone, Piero, Pennacchio, Micol, Guerri, Luciano, and Brezzi, F.

Subjects
*ELECTRONICS in cardiology, *HEART
Abstract

An integral representation of electrograms is used for large scale simulations in an anisotropic model of the whole left ventricle. Numerical artifacts, like spurious oscillations or peaks, may appear if the computational grid is not fine enough. To avoid an excessive increase in the number of elements and nodes, we present a numerical procedure based on a combination of: a special refinement of the grid, a sub-element technique, a nonlinear interpolation and a split form of the integral. The numerical simulations show that in this way it is possible to suppress the numerical artifacts thus allowing an accurate computation of electrograms in any point inside or outside the myocardial wall. [ABSTRACT FROM AUTHOR]

Published
2000
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40. Simulation Studies of Cardiac Bioelectrical Activity

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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41. Numerical Methods for the Bidomain and Reduced Models

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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42. The Inverse Problem of Electrocardiology

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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43. Parallel Solvers for the Bidomain System

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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44. Anisotropic Cardiac Sources

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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45. Basic Cardiac Anatomy and Electrocardiology

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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46. Mathematical Models of Cellular Bioelectrical Activity

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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47. Reduced Macroscopic Models: The Monodomain and Eikonal Models

Author

Franzone, Piero Colli, Pavarino, Luca F., Scacchi, Simone, Quarteroni, Alfio, Editor-in-chief, Hou, Thomas Y., Series editor, Le Bris, Claude, Series editor, Patera, Anthony T., Series editor, Zuazua, Enrique, Series editor, Colli Franzone, Piero, Pavarino, Luca Franco, and Scacchi, Simone

Published
2014
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