Effect of 28-mm Cryoballoon Ablation on Major Atrial Ganglionated Plexi

Abstract

Objectives: The authors intended to investigate if 28-mm cryoballoon (CB) ablation also modifies the 4 major atrial ganglionaated plexi (GP).

Background: The major atrial GP facilitate the initiation and maintenance of atrial fibrillation (AF). The 28-mm CB covers a large surface area of the left atrium and probably the GP areas.

Methods: High-frequency stimulation (20 Hz) was delivered to the area of anterior right GP (ARGP), inferior right GP, superior left (SLGP), and inferior left GP (ILGP). Positive GP sites were defined as a prolongation of R-wave to R-wave (RR) interval during AF by >50%. The area of each GP before and after CB ablation was compared.

Results: A total of 18 patients with paroxysmal AF who underwent CB and radiofrequency ablation and had positive GP sites were reviewed. The Wilcoxon signed-rank test was used to assess the effects of CB ablation on each GP. There was a statistically significant difference in the area of all 4 GP after CB ablation: 1) ARGP area: 2.9 cm² (interquartile range [IQR]: 2.1 to 3.5 cm²) pre-CB, 0.1 cm² (IQR: 0 to 0.6 cm²) post-CB, p = 0.0002; 2) inferior right GP area: 2.1 cm² (IQR: 0.9 to 2.9 cm²) pre-CB, 0.5 cm² (IQR: 0 to 1.7 cm²) post-CB, p = 0.001; 3) SLGP area: 1.4 cm² (IQR: 0.6 to 2.4 cm²) pre-CB, 0 cm² (IQR: 0 to 0 cm²) post-CB, p = 0.0002; and 4) ILGP area: 1.3 cm² (IQR: 0.3 to 2.2 cm²) pre-CB, 0.3 cm² (IQR: 0 to 1.6 cm²) post-CB, p = 0.008.

Conclusions: The surface area of all 4 of the major atrial GP was substantially reduced by CB ablation. The SLGP and ARGP had the largest, whereas the ILGP had the least percent of reduction following CB ablation. Part of the therapeutic effects of CB ablation may result from modifying the 4 major atrial GP.

Keywords: atrial fibrillation; autonomic nervous system; cryoballoon ablation; ganglionated plexi.