Abstract: Spiral waves of electrical activity in mammalian cardiac tissue haveb
become a major focus of research because of their central role in
arrhythmogenesis. Experiments using voltage-sensitive dyes have shown that
many dangerous arrhythmias occur because of the presence of reentrant
waves (spiral waves) of electrical activity. When a single spiral wave is
present, the resulting fast heartbeat is known as tachycardia. When a
single spiral wave becomes unstable and breaks down into many waves,
tachycardia generally transforms into lethal fibrillation.

This talk will provide a brief introduction to cardiac electrophysiology
and mathematical models for cell dynamics and will focus in particular on
how these models are used in the context of complex systems and excitable
media to study reentrant waves in cardiac tissue. Several mechanisms that
can destabilize spiral waves and produce spiral wave breakup will be
discussed along with electrophysiological characteristics of cardiac
tissue that can be associated with these mechanisms. Examples of
experiments and simulations ranging from isolated cells to anatomically
realistic three-dimensional hearts will be shown.

Beth Israel Medical Center NY