Date: 25 Mar 2008

Clinical outcome of left atrial ablation for paroxysmal atrial fibrillation is related to the extent of radiofrequency ablation

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Abstract

Background

The exact mechanism of eliminating atrial fibrillation (AF) by catheter ablation techniques is not known. We investigated whether the extent of atrial damage conferred by radiofrequency lesions is a predictor of success after ablation, regardless of the method employed for ablation.

Methods

Ninety consecutive patients with paroxysmal AF subjected to ostial–antral pulmonary vein isolation (n = 41) or circumferential (n = 49) catheter ablation were studied.

Results

At 1 year follow-up, 16 out of 41 patients (39%) with ostial–antral ablation and 16 out of 49 patients (32.6%) with circumferential ablation had AF recurrences (p = 0.5). The mean duration of radiofrequency ablation lesions was statistically significantly shorter in patients with recurrence of AF compared to those with sinus rhythm 1 year after ablation (22.3 ± 4.2 min vs. 27.2 ± 4.5 min, respectively, p value < 0.001). Radiofrequency ablation time was inversely associated with the risk of recurrence of AF 1 year after ablation and this relationship remained even after adjustment for potential confounding factors such as age, sex, left atrial size, and type of ablation technique (ostial–antral or circumferential; HR  =  0.80, 95% CI: 0.72–0.87, p < 0.001).

Conclusions

Duration of radiofrequency energy delivery is an independent predictor of clinical outcome at 1 year follow-up both among patients undergoing circumferential as well as ostial–antral ablation.