biotechnology symposium 2005 abstracts - Universität Leipzig

38
BIOMEDICAL AND CELL ENGINEERING
3.1 Modeling cardiac electric signals – From ion
channels to the ECG
Olaf Dössel
The electrocardiogramm ECG is a well-known diagnostic tool. The electrical signals that
can be measured on the surface of the body originate from electrophysiological processes
in the heart. The “sources” of these electric signals are the ion channels embedded into
the membrane of the myocytes that open and close according to basic rules. These rules
have been described mathematically fi rst by Hodgkin and Huxley. Today the complete
chain from the ion channels (nanometer scale) over the myocytes (micrometer scale) to a
description of the tissue (millimeter scale) and ending with the ECG on the body surface
(meter scale) can be described explicitly with mathematical models.
A large set of membrane proteins is taken into account today in order to describe the
electrophysiology of isolated myocytes. A very detailed description of the electrophysiology
of the heart is necessary for realistic modeling of excitation propagation. Knowing the
bioelectric source distribution in the heart the time course of the body surface potential
map BSPM can be calculated.
In future better therapeutic measures can be designed using computer models of the
human heart. It will be possible to predict the effect of new drugs on the rhythm of the
whole heart by knowing the effect on the ion channels. Optimized strategies for RF ablation
can be found. Maybe also new electrode confi gurations and pulses for electric stimulation
like they are used in a heart pacemaker or a defi brillator can be investigated.
Prof. Dr. Olaf Dössel
Universität Karlsruhe (TH)
Department of Electrical Engineering
and Information Technology
Institute of Biomedical Engineering
E-Mail: olaf.doessel@ibt.uni-karlsruhe.de
www.ibt.uni-karlsruhe.de