Bipolar catheter ablation in ventricular myocardium

Area of Science:

• Electrophysiology
• Cardiac Ablation Technologies
• Medical Device Engineering

Background:

• Catheter radiofrequency ablation (RFA) for deep myocardial arrhythmias has high recurrence rates (>40%).
• Unipolar ablation (UA) often fails to create transmural lesions, limiting its effectiveness in disrupting critical arrhythmia circuits.
• Bipolar ablation (BA) offers a potential alternative for improved transmurality.

Purpose of the Study:

• To test the hypothesis that bipolar ablation (BA) is more effective than unipolar ablation (UA) in achieving transmural lesions.
• To determine the optimal configuration for ventricular BA in creating effective and safe lesions.

Main Methods:

• Sequential UA and BA were performed on porcine ventricular septal and free wall models.
• Irrigated, contact-force sensing ablation catheters were used, oriented perpendicularly to the myocardium.
• Variables tested included return catheter type, ablation duration, irrigation fluid, and power settings to optimize BA.

Main Results:

• BA created significantly more transmural lesions with fewer steam pops compared to UA (P < .01).
• BA lesions were deeper, narrower, and larger in volume.
• Optimal BA parameters involved using an irrigated catheter as the return electrode, 30W power, and 120 seconds duration, balancing transmurality and safety.

Conclusions:

• Bipolar ablation (BA) demonstrates superior efficacy in creating transmural lesions for treating cardiac arrhythmias.
• The optimized BA configuration (irrigated return electrode, 30W, 120s) enhances lesion depth and transmurality while minimizing risks like steam pops.
• BA represents a promising advancement over UA for managing complex arrhythmias originating from deep myocardial substrates.