Long-term effects of catheter ablation for lone atrial fibrillation: progressive atrial electroanatomic substrate remodeling despite successful ablation.

BACKGROUND: Whether curative ablation can prevent progression of the atrial electroanatomic remodeling associated with atrial fibrillation (AF) is not known.
OBJECTIVE: The purpose of this study was to determine whether successful radiofrequency ablation (RFA) of AF can prevent progression of the atrial substrate associated with AF.
METHODS: Detailed right atrial electroanatomic maps from 11 patients without apparent structural heart disease undergoing RFA of AF at baseline and ≥6 months following successful RFA were compared to 11 control patients undergoing electrophysiologic evaluation of supraventricular tachycardia. Bipolar voltage, conduction, effective refractory periods (ERPs), and signal complexity were assessed.
RESULTS: At baseline compared with the control group, the AF group demonstrated (1) lower voltage (P <.001); (2) slowed conduction (P = .005); (3) more prevalent complex signals (P <.001); (4) prolonged regional refractoriness (P <.05), and (5) left atrial dilation (P = .01). At 10 ± 13 month follow-up, the AF group demonstrated the following compared to baseline: (1) lower voltage (P <.05); (2) either no improvement or further slowing of conduction; (3) further prolongation of regional refractoriness (P <.05); and (4) reversal of left atrial dilation (P <.05).
CONCLUSION: Patients with lone AF demonstrate evidence of an abnormal atrial substrate at baseline compared to control patients without AF. This substrate does not appear to reverse even after successful catheter ablation. These findings may have implications for long-term outcomes of ablation and for timing of ablative intervention.