B-AB17-04 ELECTROPHYSIOLOGICAL FINDINGS IN PATIENTS UNDERGOING LEFT ATRIAL APPENDAGE OCCLUSION FOLLOWING PREVIOUS ELECTRICAL ISOLATION

Abstract

Left atrial appendage electrical isolation (LAA) is an important adjunctive ablation strategy in patients with nonparoxysmal atrial fibrillation. If impaired mechanical function following isolation is observed, long-term oral anticoagulation (OAC) or, as an alternative, LAA occlusion are required. Although focal electrical potentials from the LAA do not result in normalization of appendage mechanical function, they may potentially be a source of arrhythmogenic triggers. Those focal areas might be challenging to ablate after Watchman implantation. We sought to report the incidence of focal electrical potentials in patients with a previously isolated LAA and transesophageal echocardiography (TEE) evidence of severely impaired LAA mechanical function undergoing Watchman implantation. In 97 patients undergoing Watchman 2.5 and Watchman FLX implantation following LAA isolation, a circular mapping catheter (CMC) was used before occlusion to document any residual LAA electrical activity. All patients had a severely impaired LAA mechanical function at pre-procedural TEE. Of 97 patients (mean age: 71±7 years; 61.9% males), 55 (56.7%) did not display any evidence of residual LAA electrical activity. In the remaining 42 (43.3%) patients, residual electrical potentials resulting in LAA reconnection were recorded on the CMC positioned into the appendage. On average, 4.6±1.2 radiofrequency energy applications (45W, mean duration of each RFA: 14.2±3.4s) were required to re-achieve complete isolation. Subsequent Watchman implantation was successful in all patients. Focal electrical activity from the LAA was documented in more than 1/3 of our patients. Although focal electrical potentials do not result in normalization of LAA mechanical function, they may potentially act as arrhythmogenic triggers. Since it may be challenging after device implantation, assessment and ablation of those areas should be considered before Watchman deployment.