Author + information
- Received November 23, 2015
- Revision received February 5, 2016
- Accepted March 17, 2016
- Published online December 1, 2016.
- Duy T. Nguyen, MDa,
- Wendy S. Tzou, MDa,
- Matthew M. Zipse, MDa,
- Joshua D. Moss, MDb,
- Lijun Zheng, MSa and
- William H. Sauer, MDa,∗ ()
- aUniversity of Colorado, Section of Cardiac Electrophysiology, Division of Cardiology, Aurora, Colorado
- bUniversity of Chicago, Section of Cardiac Electrophysiology, Division of Cardiology, Chicago, Illinois
- ↵∗Reprint requests and correspondence:
Dr. William H. Sauer, Section of Cardiac Electrophysiology, University of Colorado, 12401 East 17th Avenue, B136, Aurora, Colorado 80045.
Objectives This study sought to determine whether partially insulated focused ablation (PIFA) catheters can minimize risk of injury to critical structures, such as the phrenic nerve and atrioventricular (AV) node, during ablation of adjacent myocardial tissue.
Background PIFA catheters using thermally conductive materials may have differential radiofrequency (RF) heating properties allowing for tailored RF application with more precision.
Methods Open-irrigated, 4- and 8-mm RF ablation catheter tips were insulated partially by coating one-half of their surfaces with a layer of vinyl, silicone, vinyl–silicone, polyurethane, or a composite of aluminum oxide/boron nitride (AOBN). These coated catheters or corresponding noninsulated catheters were positioned with 10 g of force on viable bovine myocardial tissue during RF application in an ex vivo setup. Tip temperatures, power, and lesion volumes were compared. The most effective coating, AOBN, was modified further by adding fenestrations to aid in passive cooling. PIFA catheters with fenestrated AOBN coating were then tested in an in vivo porcine model to target myocardial tissue adjacent to the AV node and the phrenic nerve.
Results PIFA catheters all demonstrated higher tip temperatures, although silicone- and AOBN-catheters demonstrated this to a lesser degree. Significant differences in lesion volumes and temperature-limited powers were noted between control, silicone, and AOBN tips. Steam pops were significantly higher for silicone but not AOBN. In contrast with non-PIFA catheters, injuries to the phrenic nerve and AV node during in vivo ablations with AOBN insulation positioned over these structures were reduced significantly.
Conclusions RF ablation using catheter tips partially coated with a thermally conductive insulation material such as AOBN results in larger ablation lesion volumes without temperature limitations. Partial insulation of the catheter tip will protect adjacent critical structures during RF ablation.
Drs. Sauer and Nguyen have received significant research grants from Biosense Webster and CardioNXT; and educational grants from St Jude Medical, Boston Scientific, and Medtronic. Drs. Sauer and Nguyen have a provisional patent on partially insulated focused catheter ablation. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received November 23, 2015.
- Revision received February 5, 2016.
- Accepted March 17, 2016.
- American College of Cardiology Foundation