Ambient circulation surrounding an ablation catheter tip affects ablation lesion characteristics

Area of Science:

• Cardiovascular Research
• Medical Device Technology
• Electrophysiology

Background:

• The impact of circulating environments on radiofrequency (RF) ablation lesion formation is not well understood.
• Understanding these effects is crucial for optimizing ablation strategies and patient outcomes.

Purpose of the Study:

• To investigate how ambient circulating environments (CEs) influence the efficacy and characteristics of RF ablation lesions.
• To compare the performance of different ablation catheters under varying flow conditions in both ex vivo and in vivo models.

Main Methods:

• Ex vivo endocardial ablation using bovine myocardium with 3.5 mm open irrigated (OI), 4 mm, and 8 mm catheters under standard, high, and no-flow conditions.
• In vivo epicardial ablation in rats using OI catheters with and without circulating saline.

Main Results:

• High flow rates reduced ablation lesion volumes across all tested catheters.
• No-flow conditions resulted in smaller lesions for 4 mm and OI catheters but larger lesions for the 8 mm catheter.
• In vivo ablation with circulating fluid produced smaller lesions compared to no-flow conditions.

Conclusions:

• Increased endocardial CE flow can decrease RF ablation effectiveness.
• No-flow environments may limit RF efficacy for specific catheters (e.g., 4 mm), impacting safety and efficacy, particularly in epicardial procedures or endocardial settings with variable flow.