Cryoablation of superoparaseptal and septal accessory pathways: a single centre experience.

AIMS Radiofrequency (RF) catheter ablation in the septum close to the atrioventricular (AV) node or His bundle has an increased risk of irreversible complications. Cryothermal energy has the advantages of reversible cryomapping and increased catheter stability. This study evaluates the usefulness of cryoablation in superoparaseptal and septal accessory pathways (APs). METHODS AND RESULTS Twenty-seven consecutive patients (16 men, 11 women, median age 29 years, range 15-65) underwent cryoablation for APs either located in the superoparaseptal (n=18) or septal (n=9) area. Cryomapping, using exclusively a 6 mm tip catheter, at -30 degrees C was performed before ablation with a goal temperature of -80 degrees C for 240 s. Acute success was achieved in 26 out of 27 patients (96%). Total procedure and fluoroscopy time was 163+/-61 and 30+/-22 min, respectively. During a follow-up for a mean of 996+/-511 days, seven patients (27%) had recurrences of arrhythmia. Five out of these seven underwent a second cryoablation with successful results, giving a total success rate of 89%. Two patients developed transient second degree AV block during cryoablation; however, no permanent AV block was observed. The recurrence rate was significantly higher in patients with procedure-related transient mechanical AP block (6/7; 86%) due to catheter trauma compared with those without mechanical block (5/20; 25%; P=0.006). CONCLUSION Cryoablation of the superoparaseptal and septal APs is a safe and effective alternative to RF therapy. Procedure-related transient mechanical AP block predicts worse late outcome.