Anatomical extent of pulmonary vein isolation after cryoballoon ablation for atrial fibrillation: comparison between the 23 and 28 mm balloons

BACKGROUND: Pulmonary vein isolation seems to occur in the distal part of the ostium leaving the atrium largely unablated when using the 23 mm cryoballoon catheter ablation for atrial fibrillation. We hypothesize that ablating with the larger 28 mm cryoballoon would target a wider portion of the left atrial cavity. AIM: To compare the anatomical extent of pulmonary vein isolation using electroanatomical mapping when performing atrial fibrillation ablation with a 23 mm or a 28 mm cryoballoon. METHODS: Eight consecutive patients selected for circumferential pulmonary vein cryoballoon isolation for highly symptomatic paroxysmal atrial fibrillation were randomly assigned to ablation with the 23 or 28 mm balloon. After ablation, electroanatomical mapping was performed to compare the anatomical extent of pulmonary vein isolation between the two balloon dimensions. RESULTS: Extent of pulmonary vein isolation significantly differed when the lesions with either balloon dimensions were compared. Pulmonary vein isolation only occurred in the tubular part of the ostium when performed with the 23 mm balloon. Conversely, the lesion created with the 28 mm balloon included a larger portion of the left atrium. In fact, when using the smaller balloon (23 mm) the mean documented extent of electrical isolation was 20.7 ± 2.8% of the maps' surface, whereas it was 40.2 ± 3.9% when performing ablation with the bigger balloon (28 mm). The difference in calculated area of electrical isolation between group A and B was statistically significant (P < 0.05). CONCLUSION: Pulmonary vein isolation occurs significantly more proximally in the atrium when performing atrial fibrillation ablation with a 28 mm cryoballoon when compared with a 23 mm balloon.