Left atrial volume and dominant frequency of atrial fibrillation in patients undergoing catheter ablation of persistent atrial fibrillation.

BACKGROUND: Prior studies have suggested that left atrial (LA) volume and frequency of atrial fibrillation (AF) are associated with suboptimal outcomes in patients undergoing catheter ablation of AF. However, the interaction of these factors and their relative impact on outcome are not clear.

METHODS: Seventy-nine consecutive patients underwent catheter ablation of persistent AF. LA volume was determined by echocardiography. Electrograms from the LA appendage (LAA), coronary sinus (CS), and lead V(1) were obtained before ablation, and the dominant frequency (DF) was determined by fast Fourier transformation. The ablation strategy consisted of pulmonary vein isolation, electrogram-guided, and linear ablation.

RESULTS: The mean LA volume indexed, LA voltage, and DF in the LAA were 48 ± 16 mL/m(2), 0.58 ± 0.20 mV, and 6.3 ± 0.8 Hz, respectively. There was a significant inverse correlation between LA volume and DF in the CS (P < 0.0001, R = -0.51). The mean LA amplitude also correlated with DF in the LAA (P = 0.0008, R = 0.37). In 38 patients (48%), AF terminated during catheter ablation. Sixty-six of the 79 patients (84%) are arrhythmia-free without antiarrhythmic drugs at a mean follow-up of 14 ± 7 months after the last procedure. Advancing age was associated with recurrence (odds ratio (OR), 1.2; 95% confidence interval (CI), 1.02 to 1.42; P = 0.02), and duration of radiofrequency energy delivery was associated with a favorable outcome (OR, 0.93; 95% CI, 0.86 to 0.99; P = 0.04).

CONCLUSION: Atrial enlargement is associated with a lower AF frequency. Age and RF duration seem to be better predictors of outcome than LA volume or AF frequency.