Session P84.6

Suppression of Spiral Waves by Electric Stimulation: A Simulation Study

B Xu, S Jacquir, S Binczak*, G Laurent, JM Bilbault

Université de Bourgogne
Dijon, France

Since years it is well known that cardiac fibrillation can cause some mortal cardiac diseases. However, there are still many aspects of cardiac fibrillation's mechanisms which need to be studied. When the fibrillation happens, the propagation of electrical waves in the heart is severely disrupted. It has been observed that spiral waves involve in cardiac fibrillation. Modeling studies proved also that it is possible to induce spiral waves in cardiac model in some certain conditions. According to these studies, the dynamics of spiral waves can be changed by electric stimulations. If spiral waves are terminated, the heart's function could be restored. This provides a way of defibrillation. In this paper, our aims are to determine the optimal stimulation, such as the number of required stimulated sites and parameters (amplitude and frequency), in order to suppress spiral waves in a localized area of a cardiac tissue. Using a bidimensional FitzHugh-Nagumo (FHN) model, spiral waves have been generated using appropriate initial conditions. When the stability of these waves has been confirmed, a stimulation function introduced to FHN model delivers a train of monophasic stimulus from electrodes distributed periodically. Our results suggest that it is possible to suppress spiral waves using a grid of stimulation sites with appropriate stimulating signals. The minimum number of electrodes leading to the electrical resetting of the system is then investigated in function of the stimulation parameters (amplitude and frequency) and intrinsic parameters. We conclude on the possibility of hybrid strategies based on biological modifications of the cardiac tissue (strength of the intracellular coupling and conductance of sodium current) and the electrical stimulation, yielding to reduce the amplitude of electrical stimulation and the number of electrodes while maintaining the suppression of spiral waves.

(Abstract Control Number: 79)