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.