Eliminating the effects of motion during radiofrequency lesion delivery using a novel contact-force controller

Catheter-tissue contact force is a determinant of radiofrequency (RF) ablation lesion effectiveness. However, ablation on a beating heart is subject to force variability, making it difficult to optimally deliver consistently durable and transmural lesions. This work evaluates improvements in contact force stability and lesion reproducibility by using a catheter contact-force controller (CFC) during lesion delivery in vitro and in vivo.

Using a sheath and force-sensing catheter, an experienced operator attempted to maintain a constant force of 20 g at targets within the atria and left ventricle of a pig manually and using the CFC; the average force and contact-force variation (CFV) achieved using each approach were compared. Ablation lesions (20 W, 30 seconds, 17 mL/min irrigation) were created in bovine tissue samples mounted on a platform programmed to reproduce clinically relevant motion. CFC-assisted lesions were delivered to stationary and moving tissue with forces of 5 to 35  g. Mimicking manual intervention, lesions were also delivered to moving tissue while the CFC was disabled. Resultant lesion volumes were compared using two-way analysis of variance. When using the CFC, the average force was within 1 g of the set level, with a CFV less than 5 g, during both in vitro and in vivo experiments. Reproducible and statistically identical (P = .82) lesion volumes proportional to the set force were achieved in both stationary and moving tissue when the CFC was used.

CFC assistance maintains constant force in vivo and removes effect of motion on lesion volume during RF lesion delivery.