C U R R E N T    P R O J E C T

Modeling cardiac fibrosis and its relation to arrhythmogenicity

Background:  Atrial fibrillation is the most common arrhythmia observed in clinical practice. Its prevalence increases substantially with age. Proliferation of fibrous tissue was consistently reported in the elderly atria.

Hypotheses:  We hypothesized that fibrosis is an arrhythmogenic factor that reinforces the substrate vulnerability to arrhythmia by promoting slow conduction, reentries and conduction blocks. Other factors such as repolarization heterogeneities or ectopic foci are assumed to be needed in combination with fibrosis to trigger an arrhythmia.

Objective:  Studying the effect of fibrosis on the propagation of the cardiac impulse during paced rhythm and reentries using a combination of computer modeling and in vitro experiments.

Methods:  The dynamics of reentries will be investigated in monolayers of co-cultured cardiac myocytes and fibroblasts using optical mapping in collaboration with experimentalists. A dedicated computer model of cardiac tissue including fibrosis will be developed based on the bidomain formulation in order to reproduce and help interpret these experiments. The three-dimensional effects related to the distribution of fibrosis will be studied by extending the results to a computer model of the mouse heart. Finally, the possible clinical implications of this project will be evaluated in a computer model of the human atria including fibrosis (focusing mainly on the pulmonary vein region).

Expectations:  This work is expected to improve our understanding of the role of fibrosis in reentry and fibrillation, and provide modeling tools for the inclusion of fibrosis in electrophysiological models of the heart.

Supervisor:  Prof. C.S. Henriquez (Duke Univ.)

Funding:  Fellowship from the Swiss National Science Foundation (PA002-113171).

F O R M E R    P R O J E C T S

Simulation and analysis of electrocardiograms during atrial fibrillation,,
Signal Processing Institute, EPFL, 2005-2006,
Co-workers:  M. Lemay, Z. Ihara, L. Dang.
Supervisors:  Prof. A. van Oosterom and Prof. L. Kappenberger (Lausanne University Hospital), Dr. N. Virag (Medtronic Europe), Dr. J.-M. Vesin and Prof. M. Kunt (EPFL).

Computer simulation of atrial arrhythmias,,
Signal Processing Institute, EPFL, 2000-2004,
Co-workers:  O. Blanc, S. Zozor, L. Dang, Z. Ihara.
Supervisors:  Dr. N. Virag (Medtronic Europe), Prof. C.S. Henriquez (Duke Univ.), Dr. J.-M. Vesin and Prof. M. Kunt (EPFL), Dr. E. Pruvot and Prof. L. Kappenberger (Lausanne University Hospital).

Study of a statistical model of mass aggregation,
Master thesis, Institute of theoretical physics, EPFL, 1999-2000,
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Numerical simulation of a chip prehensor based on aerodynamic effects,
Robotic Systems Laboratory, EPFL, 1999,
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Study of irreversible statistical models: spin dynamics, sandpile models and turbulence models,
Institute of Theoretical Physics, EPFL, 1998-1999,
Supervisors:  Dr. L. Frachebourg and Prof. Ph. Martin.

Development of visualization and statistical tools for atmospheric data,
MeteoSwiss, Station Aérologique, Payerne, 1998,
Supervisor:  Dr. D. Ruffieux.

Analysis of shock waves generated by high speed trains entering a tunnel,
Fluid Mechanics Laboratory, EPFL, 1998,
Supervisors:  Dr. V. Bourquin and Dr. A. Drotz.