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Cellular electrophysiological changes induced in vitro by radiofrequency current: comparison with electrical ablation
Y Z Ge1, P Z Shao, J Goldberger
1Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, Illinois, USA.
Pacing and Clinical Electrophysiology : PACE
|February 1, 1995
Summary
Radiofrequency ablation creates smaller, more uniform lesions than direct current ablation. Both methods cause cellular damage, but radiofrequency ablation results in fewer inexcitable cells in the border zone.
Area of Science:
- Cardiovascular Electrophysiology
- Biophysics
- Medical Device Technology
Background:
- Understanding the cellular effects of ablation techniques is crucial for improving cardiac procedures.
- Direct current (DC) and radiofrequency (RF) ablation are used to treat cardiac arrhythmias, but their cellular impacts differ.
Purpose of the Study:
- To compare the cellular electrophysiological effects of RF energy delivery versus high-energy DC electrical ablation in an in vitro canine epicardial model.
- To elucidate the cellular basis for clinical observations following RF ablation.
Main Methods:
- In vitro canine epicardial strips were superfused with Tyrode's solution.
- Catheters delivered 10 J of DC energy or 40 V of RF energy to the epicardial surface.
- Cellular electrophysiology was assessed by measuring resting membrane potential, peak dV/dT, action potential amplitude, and action potential duration (APD).
Main Results:
- DC energy produced larger lesions with a wider border zone (10-12 mm) containing viable but damaged cells, including up to 36.4% inexcitable cells between 2-5 mm.
- RF energy created smaller, more homogeneous lesions with a narrower border zone (6-8 mm) and significantly fewer inexcitable cells (2.6%) between 2-5 mm.
- RF ablation resulted in severe electrophysiological abnormalities within 2 mm of the site, with only minor abnormalities further away.
Conclusions:
- RF current ablation generates smaller and more homogeneous lesions compared to DC ablation.
- Despite a smaller border zone, RF ablation leaves a region of partially depolarized but viable myocardium.
- These cellular findings correlate with clinical observations of RF ablation outcomes.