Monday, March 31, 2008
3pm in Howey Physics Lecture Room 5

 

Flavio Fenton
Dept. of Biomedical Sciences
Cornell University

 

"Understanding Wave Instabilities in Cardiac Tissue"

The heart is an electro-mechanical system: under normal conditions, electrical waves propagate throughout cardiac tissue in a coordinated manner to initiate an efficient mechanical contraction. In pathologic states, electrical wave propagation can be  destabilized and can exhibit period-doubling bifurcations that can result in both quasiperiodic and spatiotemproally chaotic oscillations. In turn, these oscillations can lead to single or multiple rapidly rotating spiral or scroll waves that inhibit contraction and can be lethal if untreated. Despite much study, little is known about the actual mechanisms that initiate, perpetuate, and terminate reentrant waves in cardiac tissue.

In this talk, I will discuss experimental and theoretical approaches to understanding the dynamics of cardiac arrhythmias. I will show how state-of-the-art voltage-sensitive fluorescent dyes can be used to image the electrical waves present in cardiac tissue, leading to new insights about their underlying dynamics. I will discuss how period-doubling bifurcations that arise at fast heart rates, in conjunction with intracellular calcium cycling and cardiac tissue anisotropy, may give rise to arrhythmias. Finally, I will show how control algorithms and the application of a series of low-voltage electrical shocks can stabilize and terminate arrhythmias and may have future clinical applications.