Modified energy settings are mandatory to minimize oesophageal injury using the novel multipolar irrigated radiofrequency ablation catheter for pulmonary vein isolation

Aims The multipolar irrigated radiofrequency (RF) ablation catheter (nMARQ (TM)) is a novel tool for pulmonary vein isolation (PVI). We investigated the incidence of thermal oesophageal injury (El) using the nMARQ (TM) for PVI. Methods and results In the initial six patients (Group 1), RF was delivered at the posterior wall with a maximum duration of 60 sand a maximum power (maxP) of 20W for unipolar ablation, and a maxP of 10W for the bipolar ablation. In the Latter 15 patients (Group 2), RF application was Limited at the posterior wall to a maximum duration of 30 sand a maxP of 15 Wfor unipolar ablation a max P of 10W for bipolar ablation. Oesophageal temperature monitoring was performed in all patients and ablation was terminated at a temperature rise >41 degrees C. Endoscopy was carried out within 2 days post-ablation. Pulmonary vein isolation was performed during sinus rhythm and was successfully achieved in 83 of 84 PVs except the septal inferior vein in one patient. Charring was seen in 3 of 21 (14.3%) patients without any evidence of embolism. Phrenic nerve patsy occurred in one patient. Endoscopy revealed severe El in 3 of 6 (50%) patients in Group 1 and in 1 of 15 patients (6.7%) in Group 2. Procedure times between Groups 1 and 2 were similar (228.3 + 60.2 min vs. 221.3 + 51.8 min; P = 0.79). Conclusion An unexpectedly high incidence of thermal El was noted following PVI using the nMARQ (TM) with the initial ablation protocol. However, the incidence of thermal El can be sigificantly reduced with limited power and RF application time at the posterior Left atrium.