Abstract 14225: Atrial Tachycardias after Surgical Left Atrial Appendage Exclusion

Introduction: Surgical left atrial appendage exclusion (LAA-Ex) is often performed to eliminate the need for long-term anticoagulation either as a stand-alone or concomitant procedure during cardiac surgery. A modified MAZE procedure is also usually performed during surgical LAA-Ex. Residual arrhythmogenic foci within the LAAA and/or zones of slow conduction along the stump of the LAA may contribute to recurrent atrial tachycardias (AT) after LAA-Ex. The purpose of this study was to determine the role of the LAA in recurrent atrial tachycardias (ATs) after surgical LAA-Ex. Methods: Catheter ablation (CA) was performed to eliminate ATs in 21 patients with history of AF (persistent in 18/21, 86%) 25±26 months after surgical LAA-Ex. There were 3 women; mean age was 66±9 years; and the left atrial diameter was 54±8 mms. A concomitant MAZE procedure and CA was performed previously, in 16 and 9 patients, respectively. Two patients had neither maze nor catheter ablation. There was residual blood flow into the LAA in 1/21 patient. Results: A reentrant AT involving the stump of the LAA was identified in 5/21 (24%) patients. Focal ablation on a critical isthmus within a zone of slow conduction along the LAA stump terminated AT in 3/5 patients. In the remaining 2 patients a linear lesion set from the stump to an existing line of block (left atrial roof line and anterior mitral annulus) terminated the macroreentrant AT revolving around the LAA stump. During 16±13 months of follow-up 10/21 patients (48%) remained free from recurrent ATs without antiarrhythmic drug therapy. A repeat ablation was performed in 3 patients, the mechanism of the AT was epicardial, perimitral, and multifocal but did not involve the LAA. Conclusions: After surgical LAA-Ex recurrent ATs are not uncommon and can involve the LAA stump, Although these ATs can be successfully identified and ablated, other ATs may recur and prompt additional antiarrhythmic or ablative therapy.