Impact of tip design and thermocouple location on the efficacy and safety of radiofrequency application

• Published in: Journal of interventional cardiac electrophysiology Vol. 66; no. 4; pp. 885 - 896
• Main Authors: Yamaguchi, Junji, Takigawa, Masateru, Goya, Masahiko, Martin, Claire, Amemiya, Miki, Yamamoto, Tasuku, Nishimura, Takuro, Nakamura, Rena, Shirai, Yasuhiro, Tao, Susumu, Miyazaki, Shinsuke, Takahashi, Yoshihide, Sasano, Tetsuo
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-06-2023; Springer Nature B.V
• Subjects: Animals; Cardiac Catheters; Cardiology; Catheter Ablation; Catheters; Contact angle; Contact force; Effectiveness; Equipment Design; Laser beam cutting; Lesions; Medical instruments; Medicine; Medicine & Public Health; Multivariate analysis; Placement; Radio frequency; Risk reduction; Safety; Steam; Swine; Therapeutic Irrigation; Thermocouples; Tissue analysis; FlexAbility™ SE; Lesion size; TactiCath™ SE; Steam pop; Catheter ablation
• ISSN: 1572-8595; 1383-875X; 1572-8595
• DOI: 10.1007/s10840-022-01219-8

Background
The FlexAbility™ SE catheter has a laser-cut 8Fr 4-mm flexible tip irrigated through laser-cut kerfs with a thermocouple 0.3 mm from the distal end. The TactiCath™ SE catheter has an 8Fr 3.5-mm tip and 6-irrigation port with a thermocouple 2.67 mm proximal to the tip. We investigated the impact of these differences on the efficacy and safety of radiofrequency (RF) applications.
Methods
RF applications at a range of powers (20 W, 30 W, and 40 W), contact forces (5 g, 15 g, and 25 g), and durations (10–60 s) using perpendicular/parallel catheter orientation were performed in excised porcine hearts. Lesion characteristics and incidence of steam pops were compared.
Results
A total of 540 lesions were examined. The FlexAbility™ SE catheter produced smaller lesion depths (4.0 mm vs. 4.4 mm,
p
 = 0.014 at 20 W; 4.6 mm vs. 5.6 mm,
p
 = 0.015 at 30 W), surface areas (22.7mm
2
vs. 29.2mm
2
at 20 W,
p
 = 0.005; 23.2mm
2
vs. 28.7mm
2
,
p
 = 0.009 at 30 W), and volumes (126.1mm
3
vs. 175.1mm
3
,
p
 = 0.018 at 20 W; 183.2mm
3
vs. 304.3mm
3
,
p
 = 0.002 at 30 W) with perpendicular catheter placement. However, no differences were observed with parallel catheter placement. Steam-pops were significantly less frequently observed with the FlexAbility™ SE catheter (4% vs. 22%,
p
 < 0.001) irrespective of catheter direction to the tissue. Multivariate analysis showed that use of the TactiCath™ SE catheter, power ≥ 40 W, contact force ≥ 25 g, RF duration > 30 s, parallel angle, and impedance drop ≥ 20Ω were significantly associated with occurrence of steam-pops.
Conclusions
The FlexAbility™ SE catheter reduced the risk of steam-pops but produced smaller lesions with perpendicular catheter placement compared to the TactiCath™ SE catheter.