Catheter Ablation of Atrial Fibrillation and Atrial Flutter : A Comparison of Cryo and Radiofrequency Techniques

Sammanfattning: Atrial fibrillation (AF) and atrial flutter (AFl) are two of the most common arrhythmias encountered in the population. Catheter ablation has emerged as a useful tool in the treatment of these arrhythmias. Although radiofrequency (RF) is the most commonly used energy source for ablation, cryoenergy may have some advantageous properties. The purpose of these studies was to evaluate and compare ablation with novel ablation catheters using either of these energy sources.When used for AFl ablation, cryoenergy was associated with less perceived pain than radiofrequency. However, the acute success rate was significantly lower for cryoablation (56%) compared with RF ablation (100%) in our study.Being one of the first centres to use a new so-called “one-shot” device for pulmonary vein isolation (PVI), the cryoballoon, we described our initial experience with this catheter in 40 patients undergoing AF ablation.  A high rate of PVI could be achieved although an additional cryocatheter was needed in 44% of the procedures. Freedom from arrhythmia-related symptoms was seen in 53% after a mean follow-up of 8.9 months.Comparing the cryoballoon and a RF-based device intended for PVI, the pulmonary vein ablation catheter (PVAC), both catheters proved comparably effective (≥93%) and safe in achieving PVI with comparable procedure times. After 12 months only 46% versus 34% (ns) in the cryoballoon- and the PVAC group, respectively, were regarded as free from AF without antiarrhythmic drugs, after one ablation procedure, whereas 60% versus 54% reported clinical success. Quality of life was significantly increased in both groups, to a level comparable with the general Swedish population.We tested the hypothesis that RF ablation would be accompanied by a higher activation of the coagulation and inflammatory systems, measured by biomarkers. Such a difference could not be supported in our study, which showed a comparable response with either technique, even though the cryoballoon caused more pronounced myocardial damage.Two different energy settings with different ratios of bipolar-to-unipolar energy were tested with the PVAC under the hypothesis that ablation with a higher proportion of unipolar energy would require fewer applications in order to achieve PVI. However, this study failed to show any difference between the groups.