Impedance and Temperature Monitoring Improve the Safety of Closed-Loop Irrigated-Tip Radiofrequency Ablation

• Published in: Journal of cardiovascular electrophysiology Vol. 18; no. 3; pp. 318 - 325
• Main Authors: THIAGALINGAM, ARAVINDA, D'AVILA, ANDRE, McPHERSON, CHRISTINA, MALCHANO, ZACHARY, RUSKIN, JEREMY, REDDY, VIVEK Y.
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.03.2007
• Subjects: ablation; Animals; arrhythmia; atrial fibrillation; Body Temperature; Catheter Ablation - instrumentation; Catheter Ablation - methods; catheterization; Electric Impedance; electrophysiology; Heart Ventricles - surgery; In Vitro Techniques; Male; Swine; Therapeutic Irrigation; ventricular tachycardia
• ISSN: 1045-3873; 1540-8167
• DOI: 10.1111/j.1540-8167.2006.00745.x

Introduction: Irrigated‐tip catheter ablation allows larger ablation lesions to be created, but also decreases catheter temperature monitoring accuracy. It is unclear which parameters should be monitored to optimize efficacy and safety during irrigated‐tip ablation. Methods and Results: Freshly excised hearts from eight male pigs were perfused and superfused using oxygenated swine blood in an ex vivo model. Ablations were performed for 1 minute using one of five different ablation protocols: (1) Temperature Control (42°C 40 W), (2) Fixed Power 20 W, (3) Fixed Power 30 W, (4) Impedance Control (target 10 Ω impedance drop), and (5) Impedance Control (target 20 Ω drop). All ablations were performed with a perpendicular orientation of the catheter to the endocardial surface. Ablation lesions depth was significantly lower in the temperature control group (5.0 ± 1.7 mm) compared with the fixed power ablation groups (6.5 ± 1.0 mm for Power 20 W, 6.6 ± 1.2 mm for Power 30 W). Impedance‐controlled ablation created lesions intermediate in depth between fixed power and temperature controlled (6.0 ± 1.6 for Impedance 10 Ω and 6.2 ± 1.4 mm for Impedance 20 Ω groups). There was a significantly greater incidence of pops and thrombus formation in the Power 20 W (9/14), Power 30 W (10/14), and Impedance 20 Ω (10/16) groups than the Temperature Control (1/16) and Impedance control 10 Ω (2/16) groups. 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 Ω drop) created lesions of comparable size to fixed‐power ablations with a significantly better safety profile.