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Simultaneous multipolar radiofrequency ablation in the monopolar mode increases lesion size
1Department of Medicine, University of Arizona College of Medicine, Tucson, USA.
Pacing and Clinical Electrophysiology : PACE
|July 1, 1996
Summary
Simultaneous radiofrequency (RF) ablation using all four poles of a quadripolar catheter created significantly larger lesions compared to using only the distal tip. This multipolar RF ablation may reduce the number of applications needed for effective arrhythmia treatment.
Area of Science:
- Electrophysiology
- Medical Devices
- Cardiac Ablation
Background:
- Radiofrequency (RF) energy delivery from electrophysiology catheter tips can create lesions insufficient for ablating arrhythmias in a single application.
- Larger lesions are desirable for more effective ablation of arrhythmogenic sites.
Purpose of the Study:
- To investigate if simultaneous radiofrequency (RF) energy delivery using all four electrodes of a quadripolar catheter can produce larger lesions compared to traditional distal tip ablation.
- To compare lesion size in vitro and in vivo using multipolar versus unipolar RF energy delivery.
Main Methods:
- RF energy was delivered via a quadripolar catheter (Webster Labs) with 4-mm tip and 2-mm ring electrodes.
- Lesion size was compared between simultaneous multipolar (all four electrodes) and distal tip unipolar configurations.
- Experiments were conducted using fresh bovine ventricular tissue (in vitro) and in dogs (in vivo).
- RF energy was delivered at a constant voltage and 400 kHz frequency, with preliminary power determination to avoid coagulation.
Main Results:
- Simultaneous multipolar RF ablation resulted in significantly larger lesions compared to distal tip ablation, both in vitro and in vivo.
- Lesion length approximately doubled in both experimental settings.
- A trend towards increased lesion depth was observed with multipolar delivery.
- Lesion width was significantly increased in the in vivo studies.
Conclusions:
- Simultaneous multipolar delivery of RF energy effectively produces larger lesions than distal tip delivery alone.
- This technique holds potential for increasing lesion size, thereby reducing the number of RF energy applications required for successful arrhythmia ablation.