How epicardial electrodes influence the transmembrane potential during a strong shock

Area of Science:

• Biomedical Engineering
• Computational Biology
• Cardiac Electrophysiology

Background:

• Defibrillation experiments are crucial for treating cardiac arrhythmias.
• Surface recording electrodes are commonly used in these studies.
• Potential artifacts from electrodes could misrepresent cardiac electrical behavior.

Purpose of the Study:

• To analyze a potential artifact introduced by surface recording electrodes during cardiac defibrillation experiments.
• To investigate the influence of electrodes on transmembrane potential during electrical shocks.
• To quantify the depolarization and hyperpolarization effects around electrodes.

Main Methods:

• Utilized the bidomain model to represent cardiac tissue electrical behavior.
• Incorporated electrode polarization impedance into the model.
• Calculated the transmembrane potential induced by a uniform electric field around a circular electrode.

Main Results:

• Identified adjacent regions of depolarization and hyperpolarization around the electrode.
• Demonstrated that induced depolarization exceeds 100 mV for a 0.5 mm radius Ag-AgCl electrode in a 500 V/m field.
• Quantified the impact of electrode size and electric field strength on transmembrane potential changes.

Conclusions:

• Surface electrodes can introduce significant artifacts in defibrillation studies.
• The observed depolarization effect may confound interpretations of cardiac tissue response to shocks.
• Results highlight the need to consider electrode artifacts in experimental design and data analysis for cardiac electrophysiology.