Open-Irrigated Laser Catheter Ablation Produces Flow-Dependent Sizes of Lesions

• Published in: Pacing and clinical electrophysiology Vol. 36; no. 9; pp. 1132 - 1137
• Main Authors: WEBER, HELMUT P., SAGERER-GERHARDT, MICHAELA
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.09.2013
• Subjects: Animals; Cardiac Catheterization - methods; contact pressure; Dogs; Dose-Response Relationship, Radiation; energy settings; irrigation flow; Laser Therapy - methods; Muscle, Skeletal - pathology; Muscle, Skeletal - surgery; open-irrigated laser catheter; Radiation Dosage; Therapeutic Irrigation; open-irrigated laser catheter; irrigation flow; contact pressure; energy settings
• ISSN: 0147-8389; 1540-8159
• DOI: 10.1111/pace.12152

Background Growth and sizes of lesions produced during catheter ablation is difficult to control. Laser lesion formation was evaluated during various flow rates and energy settings by using an open‐irrigated laser catheter on a thigh‐muscle dog model. Methods Laser radiation at 15 W or 20 W was applied in blood for 10 seconds, 20 seconds, 30 seconds, 40 seconds, and 50 seconds during an irrigation flow of 16 mL/min or 35 mL/min, in direct contact, and in a noncontact mode of laser application. Lesions were evaluated morphometrically. Results There was a linear increase of lesions with the increase of the level of energy applied. Maximal depth of lesions achieved during a flow rate of 16 mL/min at 15 W/50 seconds increased significantly from 9.9 ± 0.3 mm to 12.1 ± 0.5 mm, and at 20 W/50 seconds from 11.1 ± 0.55 mm to 12.4 ± 0.26 mm, when irrigation flow was 35 mL/min (P < 0.5). However, difference of lesion increase between 15 W and 20 W was not significant (P = 0.30). Lesions were achieved also in a noncontact mode of radiation at a distance of 1–2 mm, but not at 5 mm away. Radiation at 20 W > 40 seconds and a flow rate of 35 mL/min may cause steam pop with intramural cavitation. Conclusions By using an open‐irrigated laser catheter augmentation of catheter flow increases lesion sizes. Lesions can be achieved also in a noncontact mode of radiation. In order to avoid unwanted effects the level of energy applied must be limited.