P5700Comparison of efficacy and safety of ventricular lesions formation by unipolar and bipolar radiofrequency ablation on an animal model

Abstract Aims Despite all this technical progress, VT recurrence after unipolar ablation remains relatively high (12–47%). Bipolar ablation has been proposed as an appealing solution, which may overcome boundaries associated with unipolar ablation settings. Therefore, we have proposed an animal study to compare bipolar (BPA) vs sequential unipolar ablation (UPA) using a contact-force sensing technology on both catheters. Methods 20 large white female pigs (6 months-old, 60–70kg) underwent multiple RF ablations (30W, 60s, 30ml/min irrigation) on ventricular myocardium, from epicardial and endocardial sides. After the procedure, the animal underwent euthanasia, cardioplegia and organ excision. The hearts were fixed and underwent high-resolution cardiac MRI. Each lesion was characterized primarily in terms of volume, depth, width and transmurality. Results We evaluated 35 lesions across the intraventricular septum. No difference in volume, linear dimensions and impedance drop was observed in this area, between the two ablation settings. However, for the generation of unipolar lesions, twice the ablation time was needed. Transmurality of the lesions shows a trend in favor of BPA. We then analyzed 73 lesions from the endocardial side and 34 from the epicardial one of the ventricular free walls. Lesion transmurality was found remarkably improved in BPA (p=0.030, OR 23.73 [4.71,11.96]). Ventricular BPA lesions were significantly deeper on the epicardial side (p