Abstract 3320: Impedance and Temperature Monitoring Improve The Safety of Irrigated Tip Radiofrequency Ablation
Introduction: Irrigated tip radiofrequency (RF) catheter ablation allows larger ablation lesions to be created but also decreases the accuracy of catheter tip temperature monitoring. It is not clear which parameters are useful to monitor during irrigated tip ablation to create the largest possible lesion safely. We hypothesised that impedance monitoring may improve the safety profile of irrigated tip RF ablation.
Methods: Freshly excised hearts from 8 male pigs were perfused and superfused using oxygenated ovine blood in an ex vivo model. Ablations were performed for 1 minute using one of 5 different ablation protocols:
Temperature control (42°C 40 W)
Power control 20W
Power control 30W
Impedance control (target 10 Ohms drop) and
impedance control (target 20 Ohms drop).
All ablations were performed with a perpendicular orientation of the catheter to the endocardial surface with 10g contact pressure. Ablations were stopped if impedance rises (> 10 ohms) or pops occurred.
Results: A total of 76 ablation lesions were created. The mean power varied from 13.4 W (temperature control ablation group) to 29.8 W (30 W fixed power group). There was a significantly greater incidence of pops and thrombus formation in the Power 20W (9/14), Power 30W (10/14) and Impedance 20 Ohms (10/16) groups than the temperature control (1/16) and Impedance control 10 Ohms (2/16) groups. See table⇓ for detailed results.
Conclusion: Temperature control improved the safety profile during irrigated tip ablation in comparison with fixed power ablations but resulted in significantly smaller lesions. Impedance controlled ablation lesions (target 10 Ohm drop) created lesions of comparable size to fixed power ablations with a significantly better safety profile.