Novel Insights on the Virtual Electrode Response

6/5/00


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Table of Contents

Living State Physics

Novel Insights on the Virtual Electrode Response

Outline

The Cardiac Bidomain Model

“Virtual Electrodes”

Phenomena unique to the cardiac bidomain with unequal intracellular and extracellular anisotropies

Phenomena unique to the cardiac bidomain with unequal intracellular and extracellular anisotropies, con't

Optical Imaging Setup

Vanderbilt Cardiac Imaging System

Information from Imaging Data

Point-Electrode Excitation of Refractory Tissue

Long-Standing Puzzle

Four Modes of Cardiac Activation

Synchronous Imaging of Point Activation Patterns

Prediction

(Saypol & Roth, 1992)

Quatrefoil Reentry Predicted by the Bidomain Model

Activation Sequence

Quatrefoil Reentry from Cathodal Stimulation

Isochronal Map of Quatrefoil Reentry (Cathodal S2)

Functional Block is Characterized by Low-Amplitude Oscillation of Vm

Isochronal Map of Quatrefoil Reentry (Anodal S2)

Prediction

Endocardium - Epicardium

Heart Free in the Bath

Heart Pressed against the Front Window

Propagationless, Post-Shock Charge-Diffusion

Response during a 200-V/5-ms Shock

Preservation of Endocardial Response with Insulating Plate

The Problem of Defibrillation

Possible Answers

Tissue Response to Field Shock

Conclusion

Future Studies

Four Modes of Cardiac Activation

Author: Marc Lin