Abstract 18715: Left Atrial Pressure and Dominant Frequency of Atrial Fibrillation in Humans
Background: Atrial stretch is thought to play a role in the development of atrial fibrillation (AF). However, the precise mechanism by which stretch contributes to AF maintenance in humans is unknown.
Methods: The subjects of this study were 58 consecutive patients with persistent AF (n=40) or paroxysmal AF (n=18) undergoing left atrial (LA) ablation. LA pressure was measured before ablation. Both atria and the coronary sinus were mapped, and regional dominant frequency (DF) was determined by fast Fourier transformation.
Results: The mean LA pressure in the persistent AF group was significantly higher than in the paroxysmal AF group (18±5 vs. 10±4 mm Hg, p<0.0001). The mean DF in the persistent AF group was also higher than in the paroxysmal AF group (6.36±0.51 and 5.83±0.54 Hz, p=0.0006). In patients with persistent AF, there was a significant correlation between LA pressure and the DF at 7 regions, including the LA appendage (r=0.55, p=0.0002). The mean DF was directly related to the duration of continuous, uninterrupted arrhythmia in patients with persistent AF (r=0.51, p=0.0009). DFmax was found at the LA appendage region in 24 of the 40 patients (60%) with persistent AF (p=0.0006). In multivariate analysis, LA pressure was the only independent predictor of DFmax in the LA appendage in patients with persistent AF (p=0.04, OR 1.41, 95% CI, 1.02 to 1.94).
Conclusions: The DF of AF was directly related to LA pressure in patients with persistent AF. This suggests that atrial stretch contributes to maintenance of AF in humans by stabilizing high frequency sources. The direct relationship between arrhythmia duration and AF frequency is consistent with tachycardia-related electrical remodeling reported in experimental studies. The high prevalence of DFmax sites in the region of the LA appendage in patients with persistent AF warrants further study.
- © 2010 by American Heart Association, Inc.