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Cardiac near-field morphology during conduction around a microscopic obstacle--a computer simulation study
1Institut für Medizinische Physik und Biophysik, Karl Franzens Universität Graz, Graz, Austria. gernot.plank@uni-graz.at
Annals of Biomedical Engineering
|December 3, 2003
Summary
Conduction obstacles in cardiac tissue distort the electric near-field (E) vector loop. Despite distortions, the peak of the E loop reliably indicates the direction of cardiac electrical propagation.
Area of Science:
- Biophysics
- Cardiac Electrophysiology
Background:
- The cardiac electric near-field (E) exhibits a vector loop during depolarization.
- Observed experimental E loop morphologies deviate from theoretical predictions for continuous conduction.
Purpose of the Study:
- To investigate the influence of microscopic conduction obstacles on E vector loop morphology.
- To determine if the peak of distorted E loops remains a reliable indicator of propagation direction.
Main Methods:
- Utilized a computer model of cardiac tissue with a central conduction obstacle.
- Simulated the behavior of the electric near-field (E) in an unbounded volume conductor.
- Analyzed E vector loop morphologies and compared propagation directions (phiI(m)) with E field directions (phiE).
Main Results:
- Simulated E loop distortions closely matched experimentally observed morphologies.
- Differences between intracellular propagation direction (phiI(m)) and E field direction (phiE) were minimal (<18 degrees).
- Obstacles caused significant loop deformations, especially during initial and terminal phases of depolarization.
Conclusions:
- Microscopic conduction obstacles contribute to the variety of experimentally observed E vector loop morphologies.
- The electric near-field (E) remains a reliable indicator of the intracellularly determined direction of cardiac electrical propagation (phiI(m)).