"Perpetual motion" improves ablation outcome
REDWOOD CITY, CALIFORNIA. Catheter ablation involves a fine balance between creating an effective electrical barrier and avoiding complications such as pericardial tamponade, stroke or TIA, pulmonary vein stenosis, esophageal complications, phrenic nerve injury, and heart block. Radiofrequency ablation for atrial fibrillation (AF) has traditionally used a point-by-point technique where the catheter is held at each point to be ablated for 20 to 45 seconds so as to achieve irreversible coagulation into a scar that will prevent electrical conduction. Older solid catheters needed higher power than newer irrigated (cooled) catheters to achieve effective coagulation and thus their use was associated with an increased number of complications.

Now electrophysiologists at the Sequoia Hospital report that using an open irrigated tip catheter in a "perpetual motion" mode, rather than holding it at a specific point for an extended period of time, results in shorter procedure times, fewer complications, and an improved success rate. Their retrospective study involved 843 afibbers who underwent a total of 1,122 ablations between October 2003 and December 2009. The average age of the patients was 62 years and 28% were female. Most had persistent (50.2%) or paroxysmal (32%) with 17.8% having permanent AF. All patients underwent a circumferential PVI and a left atrium roof-line ablation as well as right and left atrial flutter ablations as needed.

In their analysis the EPs compared procedure time, success rate, and complications in four groups. Group 1 was ablated using a closed tip 8-mm catheter with maximum power setting of 70 W. In group 2 an open irrigated tip catheter (OITC) with a power setting of 40 W was used. Group 3 was treated with an OITC and a power setting of 45 W, and group 4 with an OITC at 50 W and the "perpetual motion" technique. This technique involves moving the OITC back and forth across a small area, staying at one point for only 3 to 10 seconds as opposed to holding the catheter in one position for up to 45 seconds. The small area was "painted" with the catheter until electrical silence was achieved. Outcomes for the four groups are presented in the table below:
*After initial ablation

The "cure rate" or AF-free survival for persistent AF was substantially better in group 4 (60%) than in groups 2 (35%) and 3 (43%), but was not significantly different for paroxysmal AF when comparing the three OITC groups.

The authors conclude that using the "perpetual motion" technique with an OITC at 50 W shortens procedure and fluoroscopy time, and improves outcome of catheter ablation for atrial fibrillation.

Winkle, RA, et al. Atrial fibrillation ablation: "Perpetual motion" of open irrigated tip catheters at 50 W is safe and improves outcomes. PACE, January 5, 2011 [Epub ahead of print]

Editor's comment: The idea of "painting" a small area at a time rather than holding the catheter at one point for an extended period of time intuitively makes sense and, according to this retrospective study, results in improved outcome and fewer complications.