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.

OBJECTIVE

The purpose of this study was to determine the impact of left atrial (LA) pressure on AF frequency in patients undergoing catheter ablation of AF.

METHODS

The subjects of this study were 58 consecutive patients with persistent AF (n = 40) or paroxysmal AF (n = 18) undergoing LA ablation. LA pressure was measured before ablation. Both atria and the coronary sinus were mapped, and regional dominant frequency (DF) was determined.

RESULTS

Mean LA pressure in the persistent AF group was significantly higher than in the paroxysmal AF group (18 ± 5 vs 10 ± 4 mmHg, P <.0001). Mean DF in the persistent AF group was also higher than in the paroxysmal AF group (6.36 ± 0.51 Hz and 5.83 ± 0.54 Hz, P = .0006). In patients with persistent AF, there was a significant correlation between LA pressure and DF at the LA appendage (r = 0.55, P = .0002). DF(max) was found at the LA appendage region in 24 (60%) of the 40 patients with persistent AF (P = .0006). In multivariate analysis, LA pressure was the only independent predictor of DF(max) in the LA appendage (P = .04, odds ratio 1.41, 95% confidence interval 1.02-1.94).

CONCLUSION

Higher LA pressure in patients with persistent AF implies that these patients are more vulnerable to stretch-related remodeling than are patients with paroxysmal AF. The DF of AF was directly related to LA pressure in patients with persistent AF. This finding suggests that atrial stretch may contribute to the maintenance of AF in humans by stabilizing high-frequency sources.