Catheter cryoablation of the atrioventricular node in patients with atrialfibrillation: A novel technology for ablation of cardiac arrhythmias

Introduction: Recent animal studies demonstrated the feasibility and safety of applying percutaneous catheter cryoablation technology for ablation of arrhythmogenic sites. The studies also showed that reversible "ice mapping" can be performed before creating permanent lesions. We investigated the fe asibility and safety of applying this new technology in man. Methods and Results: Cryoablation of the AV node (AVN) using a 9-French qua dripolar catheter with a 4-mm electrode tip was attempted in 12 patients (m ean age 67.8 +/- 11.4 years) with refractory atrial fibrillation, Whereas t echnical issues prevented adequate tissue contact in two patients, complete AVN block was obtained in the remaining 10 patients after 4.8 +/- 1.9 cryo applications lasting 5.5 +/- 0.2 minutes resulting in temperatures of -58.1 degrees +/- 5.4 degreesC, In all patients with sinus rhythm at the time of the procedure, cryomapping at warmer temperatures induced reversible AVN b lock and allowed confirmation of a successful site before definitive ablati on, Intracardiac echocardiography was performed in three patients and allow ed visualization of the cryocatheter-endocardial contact and cryolesion for mation. No major procedural complications were reported. After 6 months of follow-up, 8 of 10 initially successful patients remained in complete block ; 1 had partial recovery of AVN conduction manifested by atrial fibrillatio n with a slow ventricular response, and 1 fully recovered AVN conduction. Conclusion: (1) Catheter cryoablation of the AVN can be performed safely in man. (2) Reversible cryomapping is feasible and may offer an advantage ove r radiofrequency ablation, (3) Cryoeatheter-endocardial contact and cryoles ion growth can be monitored with intracardiac echocardiography.