Radiofrequency Ablation Using an Open Irrigated Electrode Cooled With Half-Normal Saline

Area of Science:

• Cardiovascular Ablation Technologies
• Electrophysiology Research
• Biomedical Engineering

Background:

• Ventricular arrhythmias can originate deep in the myocardium, proving refractory to standard radiofrequency ablation (RFA).
• Current RFA techniques using normal saline (NS) irrigation may not achieve sufficient lesion depth for these challenging cases.
• Reducing irrigant ionic concentration is a potential strategy to enhance lesion penetration.

Purpose of the Study:

• To evaluate half-normal saline (HNS) as a cooling irrigant for radiofrequency ablation (RFA).
• To compare lesion sizes created with HNS versus normal saline (NS) irrigation in both ex vivo and in vivo models.
• To assess the potential of HNS for creating deeper ablation lesions.

Main Methods:

• Ex vivo studies utilized bovine myocardium with sequential unipolar and bipolar radiofrequency ablation (RFA) using HNS and NS.
• In vivo studies involved unipolar HNS-RFA in a porcine ventricular model, compared to NS.
• Lesion size and volume were quantified to compare the efficacy of different irrigation solutions.

Main Results:

• Unipolar RFA with HNS produced larger lesions than unipolar RFA with NS ex vivo.
• Ex vivo bipolar RFA with HNS resulted in the largest lesion dimensions.
• In vivo unipolar HNS-RFA in porcine ventricles created significantly larger lesion volumes (152.9 ± 29.2 μl) compared to NS (94.7 ± 33.4 μl).

Conclusions:

• Decreasing irrigant ionic concentration with HNS in RFA can create larger ablation lesions.
• HNS irrigation may offer a viable strategy for ablating deep myocardial circuits resistant to standard ablation.
• Further research is warranted to validate this novel RFA approach for clinical application.