Impact of pharmacological autonomic blockade on complex fractionated atrial electrograms.

INTRODUCTION: The influence of the autonomic nervous system on the pathogenesis of complex fractionated atrial electrograms (CFAE) during atrial fibrillation (AF) is incompletely understood. This study evaluated the impact of pharmacological autonomic blockade on CFAE characteristics. METHODS AND RESULTS: Autonomic blockade was achieved with propanolol and atropine in 29 patients during AF. Three-dimensional maps of the fractionation degree were made before and after autonomic blockade using the Ensite Navx system. In 2 patients, AF terminated following autonomic blockade. In the remaining 27 patients, 20,113 electrogram samples of 5 seconds duration were collected randomly throughout the left atrium (10,054 at baseline and 10,059 after autonomic blockade). The impact of autonomic blockade on fractionation was assessed by blinded investigators and related to the type of AF and AF cycle length. Globally, CFAE as a proportion of all atrial electrogram samples were reduced after autonomic blockade: 61.6 +/- 20.3% versus 57.9 +/- 23.7%, P = 0.027. This was true/significant for paroxysmal AF (47 +/- 23% vs 40 +/- 22%, P = 0.003), but not for persistent AF (65 +/- 22% vs 62 +/- 25%, respectively, P = 0.166). Left atrial AF cycle length prolonged with autonomic blockade from 170 +/- 33 ms to 180 +/- 40 ms (P = 0.001). Fractionation decreases only in the 14 of 27 patients with a significant (>6 ms) prolongation of the AF cycle length (64 +/- 20% vs 59 +/- 24%, P = 0.027), whereas fractionation did not reduce when autonomic blockade did not affect the AF cycle length (58 +/- 21% vs 56 +/- 25%, P = 0.419). CONCLUSIONS: Pharmacological autonomic blockade reduces CFAE in paroxysmal AF, but not persistent AF. This effect appears to be mediated by prolongation of the AF cycle length.

Prospective randomized comparison between the conventional electroanatomical system and three-dimensional rotational angiography during catheter ablation for atrial fibrillation.

BACKGROUND: Theoretically, the use of electroanatomical mapping systems may reduce radiation exposure, while three-dimensional rotational atriography (3DATG) may increase exposure. Anatomical representation and image registration using 3DATG are likely to be superior, but the net clinical benefit of either system is unknown. OBJECTIVE: The purpose of this prospective randomized two-center study was to compare the procedural and clinical outcome of patients with atrial fibrillation (AF) treated by catheter ablation using either three-dimensional (3D) electroanatomical mapping (Carto) or 3DATG. METHODS: From November 2007 to November 2008, 91 consecutive patients with AF (mean age 58 +/- 10 years; 63% paroxysmal AF, 37% persistent AF) from two centers (Bordeaux and Boston) were randomized to ablation using either 3DATG (44 patients) or Carto (47 patients). RESULTS: Of the 47 left atrial shells acquired with 3DATG, one was uninterpretable. There was no difference in total radiofrequency applications (72 +/- 23 vs. 79 +/- 33 minutes, respectively, P = .296), procedural duration (232 +/- 65 vs. 218 +/- 67 minutes; P = .335), fluroroscopic duration (75 +/- 28 vs. 67 +/- 26 minutes; P = .151), or radiation exposure (71,810 +/- 42,954 vs. 68,009 +/- 38,345 mGy cm(2); P = .719) between procedures performed with 3DATG or Carto. After a mean follow-up of 10 +/- 4 months, there was no difference in clinical outcome using either Carto or 3DATG concerning total arrhythmia recurrence (34% versus 38%; P = .668) or AF recurrence (20% vs. 15%; P = .555). CONCLUSION: Three-dimensional ATG-guided AF ablation has similar radiation exposure and procedural and outcome characteristics compared with Carto-guided ablation. The ease of use and accurate 3D representation of the left atrium make 3DATG a reasonable alternative to conventional 3D electroanatomical mapping systems, however, without advanced mapping functions.