Results of a prospective randomised evaluation of using high power during CLOSE-guided pulmonary vein isolation (PVI) using the Thermocool Smarttouch (Biosense Webster) device—the POWER-AF study—have been published online in Circulation: Arrhythmia and Electrophysiology.
Authors Jean-Yves Wielandts (Department of Cardiology, AZ Sint-Jan Hospital, Bruges, Belgium) et al describe CLOSE-guided atrial fibrillation (AF) ablation is based on contiguous, optimised point-by-point radiofrequency (RF) lesions, but note that the optimal RF power remains unknown.
POWER-AF, a monocentric study including patients with paroxysmal AF, planned for first CLOSE-guided PVI using a contact force RF catheter. A total of 100 patients were randomised into two groups (1:1), with the control group receiving AF ablation using the standard CLOSE protocol (35W), while in the experimental group PVI was performed using high power (45W). Endoscopic evaluation was performed in patients with an intraesophageal temperature rise greater than 38.5 degrees.
A total of 96 patients were included in the study, with 48 randomised to each group. The study team reports that in the high power group, patients experienced a shorter procedure time (80 minutes vs. 102 minutes, p<0.001), a shorter total RF application time [16 minutes vs. 26 minutes (p<0.001)] and RF time per application [26 vs. 37 seconds anteriorly, p<0.001 and 13 vs. 17 seconds posteriorly, p<0.001].
Endoscopic evaluation, which was performed in 19 patients in the high power group and 25 patients in the control group patients respectively (p=0.31) showed an ulcerative perforation in a high power group patient and a superficial ulcerative lesion in a control group patient. Six-month AF recurrence was not significantly different between the two groups, they note (10% in High Power vs. 8% in Control, p=0.74).
In conclusion, the study team writes: “This randomised controlled study shows that a 45W RF-power CLOSE-protocol in paroxysmal AF patients significantly increases the global procedural efficiency with similar mid-term efficacy. However, our study showed a narrower safety margin and a limited increased efficiency at the posterior wall using high power. This advocates against the use of high power in the region neighbouring the oesophagus.”