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Electrode polarity does not alter the initial ventricular activation sequence during pacing with extracardiac
P J Birkui1, P Savard, F Hélie
1INSERM U256 Hôpital Broussais, Paris, France.
Pacing and Clinical Electrophysiology : PACE
|December 1, 1995
Summary
External cardiac pacing using extracardiac electrodes shows that electrode polarity does not significantly alter ventricular activation sequences. This finding suggests a need to revise standard electrode nomenclature for pacing applications.
Area of Science:
- Cardiovascular Electrophysiology
- Medical Device Technology
Background:
- External cardiac pacing is crucial for managing arrhythmias.
- Understanding the electrical field generated by extracardiac electrodes is essential for effective pacing.
Purpose of the Study:
- To investigate the cardiac electrical response to external pacing in dogs.
- To determine the influence of electrode type, position, and polarity on ventricular activation sequences.
Main Methods:
- Ventricular epicardial mapping in six anesthetized dogs with induced atrioventricular block.
- Utilized a 127-unipolar electrode array and computer-generated isopotential and isochronal maps.
- Applied unipolar stimulation pulses using various cutaneous and esophageal electrodes.
Main Results:
- Epicardial electrical field was primarily dependent on electrode position, not type.
- Anteroposterior and anteroesophageal electrode configurations produced a consistent apex-to-base potential gradient.
- Ventricular activation sequences showed interindividual consistency despite stimulation protocol changes.
- Inverting electrode polarity did not significantly alter the origin of ventricular activation.
Conclusions:
- Electrode polarity has minimal impact on ventricular activation sequences during extracardiac pacing.
- Current nomenclature defining the negative electrode as "active" may require revision.
- Electrode position is a more critical factor in determining pacing-induced electrical fields.
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