Related Experiment Videos
Energy steering of biphasic waveforms using a transvenous three electrode system.
F M Leonelli1, K E Wang, C King
1Division of Cardiovascular Medicine, University of Kentucky, Lexington, USA.
Pacing and Clinical Electrophysiology : PACE
|July 7, 1999
Summary
Optimizing endocardial defibrillation waveforms by steering shock current through three electrodes significantly reduced the energy required for defibrillation. Shocks delivered primarily via the right ventricle (RV) to superior vena cava (SVC) + pectoral can (C) pathways proved most effective.
Area of Science:
- Cardiovascular Medicine
- Biomedical Engineering
- Electrophysiology
Background:
- The optimal electrode configuration for endocardial defibrillation remains debated.
- Current two-pathway systems (right ventricle [RV] cathode, SVC + pectoral can anode) show effectiveness, possibly due to uniform voltage gradients.
- Investigating three-electrode systems offers potential for waveform optimization.
Purpose of the Study:
- To hypothesize that varying current distribution in a three-electrode system can yield more effective defibrillation waveforms.
- To compare the characteristics and efficacy of six biphasic waveforms using different electrode configurations.
- To determine the impact of current steering on defibrillation energy requirements.
Main Methods:
- Twelve pigs were used to test six biphasic waveforms with varying current distribution between RV-->C and RV-->SVC + C pathways.
- Configurations included exclusive two-pathway use (RV-->C or RV-->SVC + C) and sequential/combined three-pathway use.
- Waveform characteristics (impedance, pulse width, tilt, peak/average current) and defibrillation efficacy (stored energy DFT) were measured.
Main Results:
- Increasing the fraction of current delivered via RV-->SVC + C pathways decreased impedance and pulse width, while increasing tilt, peak, and average current.
- Waveforms with 75% or 100% of their duration using RV-->SVC + C pathways required significantly lower stored energy for defibrillation.
- Altering current distribution among three electrodes generates distinct waveforms and optimizes energy delivery.
Conclusions:
- Current distribution during defibrillation shocks can be actively controlled in three-electrode systems.
- Steering 75% or more of the shock current to the RV-->SVC + C pathways significantly lowers the energy needed for defibrillation.
- This energy steering technique holds promise for optimizing current delivery and improving defibrillation outcomes.