Background: Although proposed to facilitate pulmonary vein isolation (PVI), high-power ablation may favor extracardiac damage. Negative component abolition of the unipolar signal reflects lesion transmurality. The present study sought to evaluate the safety and efficacy of high-power ablation using unipolar signal modification as a local end point. Methods High power and standard power were compared in 4 swine and 100 consecutive patients referred for PVI. The first 50 patients were included in the control group (25–30 W) and the last 50 patients in the study group (40–50 W). Atrial radiofrequency applications were stopped 2 s (study group and swine) or 5 s (control group) after unipolar signal modification. Ventricular radiofrequency applications of 500 J (25 W·20 s versus 50 W·10 s) were performed at the swine epicardium. Results: Swine gross necropsy did not show any extracardiac damage related to atrial lesions. At equal energy of 500 J, 50 W lesions were deeper (3±0.9 versus 2.6±1.1 mm; P =0.03) and wider (6.2±2 versus 5±2.3 mm; P =0.006) than 25 W lesions. No complications occurred during the clinical study, whatever the power output used for PVI. For a similar sinus rhythm maintenance at 12 months (90% versus 88%; P =0.75), the study group displayed higher first-pass PVI (92% versus 73%; P <0.001), lower acute pulmonary vein reconnection (2% versus 17%; P <0.001), reduced procedure time (73.1±18.2 versus 107.4±21.2 min; P <0.001), and ablation time (13±2.9 versus 30.3±8.8 min; P <0.001). Conclusions: High-power PVI guided by unipolar signal modification safely decreases procedural burden while ensuring robust 12-month outcomes.

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