Mathematics Colloquium
3:00 p.m.
Math Annex 1100
Jim Keener
University of Utah
The Importance of Microstructure in Defibrillation
Defibrillation of cardiac muscle by the application
of a large brief current is used routinely in hospitals
to save hundreds of lives daily. Although this technique
was discovered in the late 1940's and has been steadily
improved since then, until recently there has been no
theory describing how or why defibrillation works. In fact,
previous theory predicted that it cannot work, even though
it obviously does.
Within the last few years a theory describing the mechanism
of defibrillation has been proposed. This theory exploits
the spatial inhomogeneity of the normal heart. However,
a substantial controversy remains about the nature of the
most important inhomogeneities, with one view favoring large
scale inhomogeneities, such as anisotropy and changes
in fiber direction, and another favoring small scale
inhomogeneities.
In this talk, I will describe this proposed mechanism
for cardiac defibrillation and use homogenization theory
to develop a mathematical model that shows when it works
and why it fails. I will also demonstrate why there is a
crucial dependence on the spatial scale of inhomogeneity.
Refreshments will be served at 2:45 p.m. in the Faculty Lounge,
Math Annex (Room 1115).
