NSC Seminar Ectopic activity in 2-dimenstional cultures of cardiac tissue

2006-03-16 13:00 - 2006-03-16 14:30
Alain Pumir (Institut Non Lineaire de Nice)
Ectopic sources are believed to play a crucial role in the generation and development of cardiac arrhythmias, especially during or shortly after an infarct. To gain a better understanding on the mechanisms leading to arrhythmias, a systematic study has been conducted in favourable conditions. The experimental results show the importance of two parameters : the cell to cell coupling, and the ’cell automaticity’, that characterizes whether a cell is spontaneously oscillatory or not. The heterogeneity of cell properties plays a key role in this work. The work can be summarized by a phase diagram, as a function of these two parameters.I will briefly describe the experimental results, then, I will introduce a simplified model that allows us to reproduce numerically the network behavior as well as the transition between the different regimes (including completely silent, isolated activity of a cell or a cluster of cell, partial propagation of waves, and synchronized activity over the whole system). Analytical estimates obtained in a few simple cases will be also discussed.