Segment by segment linear ablation with an articulated bilimb catheter: initial experimental results

Area of Science:

• Cardiovascular Medicine
• Electrophysiology
• Medical Devices

Background:

• Transcatheter radiofrequency (RF) ablation for atrial fibrillation/flutter necessitates linear lesions.
• Conventional catheters face limitations in endocardial contact, lesion size, and penetration, impacting efficacy.

Purpose of the Study:

• To evaluate the efficacy and safety of a novel RF ablation catheter designed for creating long myocardial lesions in the right atrium.
• Assess the performance of a catheter with perpendicularly contacting articulated bilimb electrodes and an irrigated planar interface.

Main Methods:

• RF ablation was performed in the right atria of 14 anesthetized sheep using three incremental power levels (25-75 W).
• Three electrode prototypes were tested, aiming for fully transmural (FT) lesions, defined by continuous epicardial and endocardial imprints.
• Lesions were examined macroscopically and histologically 1 hour post-ablation.

Main Results:

• 86% of lesions were fully transmural (FT) at higher power levels (55-75 W), compared to 37% at lower levels (25-45 W).
• Histology confirmed continuous FT lesions in most cases, forming coalescent linear lesions averaging 25 x 6 x 4 mm.
• Post-ablation electrograms showed significant amplitude reduction, indicating effective electrical isolation, with no perforations observed.

Conclusions:

• The novel bilimb electrode catheter can create continuous, fully transmural lesions in various sheep atrial regions, including trabeculated areas.
• This catheter demonstrates potential as an improved tool for catheter ablation procedures targeting atrial fibrillation and flutter.
• Stable endocardial contact and effective lesion creation suggest enhanced safety and efficacy for future clinical applications.