LONDON, UNITED KINGDOM. Initial complete success rates (no AF, no antiarrhythmics) for catheter ablation at high-volume centers average between 50 and 60% at the 1-year follow-up. The main cause of failure is recovery of electrical conduction between the pulmonary veins and the left atrium through the development of gaps in the originally complete lesion rings around the pulmonary veins. The primary aim of repeat procedures is to re-ablate the gaps and doing so can bring success rates to 85% or higher for paroxysmal afibbers. A group of electrophysiologists from St. Bartholomew's Hospital now report that a combination of standard radiofrequency (RF)-powered pulmonary vein isolation and balloon-based cryotherapy may eliminate the need for repeat ablations.
The study involved 25 consecutive paroxysmal afibbers who underwent a first circumferential (wide area) pulmonary vein isolation procedure, 25 paroxysmal afibbers who underwent cryotherapy using a cryo-balloon (88% used a 28-mm balloon) and 25 who were treated with a combination of the two approaches. Follow-up ranged from 1.4 to 2.2 years. Complete success rate at the 1-year follow-up (freedom from symptomatic episodes) was 52% in the RF ablation group, 56% in the cryoablation group, and 80% in the combined group. No complications were observed in the RF only group, but two phrenic nerve palsies, which recovered by 3 months, and one groin hematoma occurred in the cryo only and combined treatment groups. The total average procedure time was slightly longer in the combined group (229 minutes) than in the RF only group (197 minutes), and the cryo only group (185 minutes). The additional cost involved in the combined procedure was $3360 US. The British EPs conclude that the combined approach is safe and significantly more effective than stand-alone RF ablation, or stand-alone cryotherapy.
Tayebjee, MH, Schilling, RJ, et al. Pulmonary vein isolation with radiofrequency ablation followed by cryotherapy. Europace, Vol. 13, 2011, pp. 1250-55
Editor's comment: It makes sense that creating two sets of lesions isolating the pulmonary veins from the left atrium is more effective than just one set. However, the study was really just a feasibility study and larger, randomized studies with longer follow-up periods are needed to confirm the superior efficacy of the combined procedure. Nevertheless, substantial cost savings could, no doubt, be realized if the combined approach would eliminate the need for repeat procedures in a significant number of cases.