Mapping Atrial Fibrillation After Surgical Therapy to Guide Endocardial Ablation.

Background: Surgical ablation for atrial fibrillation (AF) can be effective, yet has mixed results. It is unclear which endocardial lesions delivered as part of hybrid therapy' will best augment surgical lesion sets in individual patients. We addressed this question by systematically mapping AF endocardially after surgical ablation and relating findings to early recurrence, then performing tailored endocardial ablation as part of hybrid therapy.

Methods: We studied 81 consecutive patients undergoing epicardial surgical ablation (stage 1 hybrid), of whom 64 proceeded to endocardial catheter mapping and ablation (stage 2). Stage 2 comprised high-density mapping of pulmonary vein (PV) or posterior wall (PW) reconnections, low-voltage zones (LVZs), and potential localized AF drivers. We related findings to postsurgical recurrence of AF.

Results: Mapping at stage 2 revealed PW isolation reconnection in 59.4%, PV isolation reconnection in 28.1%, and LVZ in 42.2% of patients. Postsurgical recurrence of AF occurred in 36 patients (56.3%), particularly those with long-standing persistent AF (=0.017), but had no relationship to reconnection of PVs (=0.53) or PW isolation (=0.75) when compared with those without postsurgical recurrence of AF. LVZs were more common in patients with postsurgical recurrence of AF (=0.002), long-standing persistent AF (=0.002), advanced age (=0.03), and elevated CHADS-VASc (=0.046). AF mapping revealed 4.4±2.7 localized focal/rotational sites near and also remote from PV or PW reconnection. After ablation at patient-specific targets, arrhythmia freedom at 1 year was 81.0% including and 73.0% excluding previously ineffective antiarrhythmic medications.

Conclusions: After surgical ablation, AF may recur by several modes particularly related to localized mechanisms near low voltage zones, recovery of posterior wall or pulmonary vein isolation, or other sustaining mechanisms. LVZs are more common in patients at high clinical risk for recurrence. Patient-specific targeting of these mechanisms yields excellent long-term outcomes from hybrid ablation.