Spatial Thermodynamics of very High Power-Short Duration Catheter
Ablation for Pulmonary Vein Isolation in an in-vivo model
Abstract
Introduction: The spatial thermodynamics of very high power-short
duration (vHPSD) radiofrequency (RF) application during pulmonary vein
isolation (PVI) in in-vivo model has not been well characterized. This
study was conducted to investigate the distance-temperature relationship
during vHPSD-RF ablation. Methods: PVI was performed using the vHPSD
catheter with the settings of 90W, RF time of 4 sec and 15mL/min
irrigation in a canine model. Catheter contact force (CF) of 10-20g was
defined as ‘normal’ and CF >20g as ‘firm’ CF. Tissue
temperature was monitored using thermocouples implanted at the surface
of the left atrial-pulmonary vein junction, left phrenic nerve, and the
luminal esophagus. PVI using a standard contact-force sensing catheter
(SCF) (settings of 35W, 30sec and 30mL/min irrigation) was performed for
comparison. Results: A total of 334 TC profiles in 4 animals was
investigated. Time to maximum tissue temperature (MTT) (6.0sec
[vHPSD/normal CF] vs. 30.5 sec [SCF/normal CF],
p<0.001; 8.0sec [vHPSD/firm CF] vs. 24.0sec [SCF/firm
CF], p=0.022) was shorter with vHPSD than in SCF groups. MTT within
10mm from catheter-tip was lower in vHPSD ablation with normal CF than
using SCF ablation (median 41.9°C [interquartile-range; 40.2-46.1]
vs. 49.5°C [45.9-56.2], p=0.013). The distance margin to keep the
MTT below 39ºC, 42ºC, and 50ºC were 4.9mm, 4.2mm, and 3.4mm,
respectively in the vHPDS group. This margin was larger (8.0mm, 6.6mm,
and 4.6mm) in the SCF group. Conclusion: Our study underscores that
vHPSD creates greater resistive heating than conventional catheter
ablation.