Electrical isolation of pulmonary veins using cryothermal energy: study design and initial results.

BACKGROUND: Atrial fibrillation (AF) is the most frequently encountered arrhythmia. Radiofrequency pulmonary vein (PV) ablation is promising for symptomatic paroxysmal AF, but is associated with a significant risk of PV stenosis.
OBJECTIVES: To assess the efficacy of cryothermal PV ablation and the incidence of PV stenosis.
METHODS: Highly symptomatic patients with paroxysmal or persistent AF were eligible for cryothermal ablation. Multislice spiral CT scans were performed before, and three months after ablation. AF burden was assessed using transtelephonic ECG recording and by telephonic enquiry.
RESULTS: An attempt was made to isolate 27 PVs in 15 patients. In total, 20 PVs could be isolated (74% acute success). No significant difference in PV diameter was seen before and after ablation. Five out of 12 patients with paroxysmal AF were completely without AF after one ablation procedure. An additional two patients reported a significant reduction in symptoms. In the three patients with persistent AF no improvement was reported.
CONCLUSION: Cryothermal PV ablation was effective in isolation of the targeted PVs. It appears to be safe, as no PV stenosis was seen in this study three months after the ablation. Taking into account a learning curve, we consider the clinical results to be very promising.