Introduction. While several studies have compared the radiofrequency current (RFC) and cryoablation for the treatment of patients with atrial fibrillation (AF), no study has monitored the long-term outcomes with the usage of implantable loop recorders (ILRs). Methods. We enrolled 89 consecutive patients with nonvalvular paroxysmal AF (N=44 for RFC and N=45 for cryoballoon). The primary efficacy end point was the assessment of effectiveness for each group (RFC versus cryoballoon) when examining freedom from arrhythmia by monitoring with ECG, Holter, and implantable loop recoder (ILR). The primary safety end point compared rates of adverse events between both groups. The secondary efficacy end point examined the duration of the postablation blanking period from ILR retrieved data. Results. The mean age of the study population was 56.6±10.2 years, and the follow-up duration was 12 months. There were no differences in baseline patient characteristics between groups. At 12 months, the absolute effectiveness (measured by ILR) was 65.9% in the RFC group and 51.1% in the cryoballoon group (OR = 1.85; 95% CI: 0.79–4.35; p=0.157), and the clinical effectiveness (measured by ECG and Holter) was 81.8% in the RFC group and 55.6% in the cryoballoon group (OR = 3.6; 95% CI: 1.37–9.46; p=0.008). There was no difference in safety between both groups. Asymptomatic episodes were significantly more present in the RFC group as measured by ILRs (p<0.010). In cryoballoon group, arrhythmia episodes were recorded equally irrespective of the follow-up method (i.e., ECG and Holter versus ILR (p>0.010)). The blanking period does not seem to be as important in cryoballoon as compared to RFC. Conclusion. RFC and cryoballoon ablation had similar absolute effectiveness at 12 months. ECG and Holter were effective when assessing the efficacy of the cryoballoon ablation; however, in the RFC group, ILR was necessary to accurately assess long-term efficacy.
Radiofrequency current directed across the mitral anulus with a bipolar epicardial-endocardial catheter electrode configuration in dogs.