Modified Unipolar Return Pulsed Field Ablation in Ventricular Myocardium

Area of Science:

• Cardiovascular Research
• Medical Devices
• Electrophysiology

Background:

• Pulsed field ablation (PFA) parameters are being optimized to enhance lesion depth.
• This study investigates a modified unipolar return PFA system for creating deep lesions in ventricular myocardium.

Purpose of the Study:

• To evaluate a modified unipolar return PFA system for its ability to generate deep lesions.
• To compare the efficacy of the modified system against a conventional unipolar return system.

Main Methods:

• Numerical modeling was employed to compare system configurations.
• Ablation procedures were conducted in 14 swine (healthy and infarcted models).
• Lesion creation utilized a focal catheter with an inferior vena cava return electrode, employing biphasic, microsecond pulses.

Main Results:

• Numerical modeling indicated the modified system produced deeper, less variable lesions than the skin patch.
• In healthy swine, lesion depths up to 11.6 mm were achieved with 16 pulse trains.
• In infarcted swine, lesions consistently penetrated fibrotic scar tissue, with 57% showing epicardial involvement.

Conclusions:

• The modified unipolar return PFA system effectively creates large, transmural lesions in both healthy and infarcted swine ventricles.
• This system demonstrates potential for improved lesion depth, width, and consistency compared to conventional unipolar PFA.