Abstract 3505: Spectral Mapping Guided AF-Nests Ablation of Paroxysmal and Permanent AF: Implications of Automatic Firing during RF Delivery and Procedural Outcomes
Background: PVI at its antrum level (PVAI), combined with isolation of the superior vena cava (SVCI) has improved long-term ablation success of paroxysmal (PAF) and persistent/permanent (PS/PM-AF). Real time spectral mapping (SM) in sinus rhythm (SR) identifies sites with disorganized frequencies, namely fibrillar atrial myocardium or AF-Nest (AFN). The spectral characteristics of AFNs may be an expression of regional clusters of autonomic nerve system (ANS) possibly creating different degrees of anatomical and/or functional abnormalities that could lead to focal cellular disarray, anisotropic conduction and triggering atrial automaticity (firing).
Purposes: To assess if automatic firing (possibly due to direct stimulation of nerve terminals) could result from RF current delivery at AFN sites localized in both atria and within the coronary sinus (CS). To determine if adjunctive AFN ablation improves outcome.
Methods and Results: One hundred and forty consecutive pts underwent ablation of PAF (N=84) and PS/PM-AF (N=56). Following PVAI, spectral mapping and ablation of AFN was performed in sinus rhythm. The AFNs (29±13 AFN sites per pt) were typically found in the low crista terminalis and adjacent low lateral right atrium (CT-RA), left atrial appendage (LAA), RA inferior to the CSos, RA-SVC junction (septal aspect) and CS (middle and distal). Firing (short, fast and irregular atrial bursts) during AFN ablation along the CT-RA was virtually present in all pts. Firing was often seen with AFN ablation in the CS, LAA and RA-SVC. At times, firing triggers AF despite of having completed PVAI. Success following a single procedure (defined as freedom of AF or Atrial Tachycardia (AT) recurrences during F/U=193±46 days): PAF (AF 92%, AT 97%); PS/PM-AF (AF 95%, AT 84%).
Conclusions: Automatic firing is commonly induced during RF delivery at AFN sites, particularly at CT-RA, LAA and CS. This hybrid ablation strategy has favorably improved long-term AF ablation outcome. Whether AFN ablation modulates an unbalanced ANS potentially responsible for initiation and maintenance of AF remains to be demonstrated.