Atrial linear lesions: Feasibility using cryoablation

Abstract

Although focal ablation has become an accepted approach to treat AF it is associated with a high arrhythmia recurrence rate. Therefore, the concept of creating linear lesions in the right or left atrium is of great interest as well. However, the creation of long linear lesions using RF ablation is extremely difficult. Therefore, the aim of our study was to asses whether the creation of a long linear lesion in the right atrium is possible using cryotherapy. A right atrial septal linear lesion was performed in 6 pigs. The ablation procedure was performed with a 7 F Freezor cryocatheter (CryoCath Technologies). The non-fluoroscopic mapping system LocaLisa was used as a navigation tool. The CARTO system was used for the evaluation of the linear lesions. Furthermore, all animals were sacrificed immediately after the ablation procedure and a post-mortem examination of the lesions was performed. Additionally, an analysis of the amplitudes of the intracardiac electrograms registered via the ablation catheter was performed before and after the ablation procedure. A right atrial septal linear lesion could be performed successfully in all 6 pigs. For the performance of this ablation line, a median number of 16 (range: 15) cryoapplications was necessary. The amplitudes of the intracardiac electrograms registerd via the ablation catheter decreased significantly after the ablation. Similarly, a CARTO bipolar voltage map revealed very low potentials among the ablation line in all pigs. There was a sharply demarcated ablation line in all pigs. Further analysis of the CARTO maps revealed an incomplete conduction block in all pigs. This was mostly due to a gap in the area of the fossa ovalis. The creation of long linear lesions using cryoablation is feasible and safe. Lesion characteristics are different and more favourable in comparison to RF-lesions. However, lesion transmurality was lacking especially in the area of the fossa ovalis.