The left atrial appendage (LAA) has been demonstrated to be the major source of thromboemboli in patients with atrial fibrillation.1 The rationale of LAA closure is based on eliminating LAA continuity with the left atrium (LA), thereby reducing stroke risk. Indeed, left atrial appendage occlusion (LAAO) procedures play an important role in anticoagulation-intolerant patients who are at risk for atrial fibrillation–related stroke. Based on the PROTECT AF (Watchman Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation)2 and PREVAIL (Prospective Randomized Evaluation of the WATCHMAN LAA Closure Device in Patients With Atrial Fibrillation [AF] Versus Long Term Warfarin Therapy)3 studies, the Food and Drug Administration (FDA) approved use of the Watchman (Boston Scientific, Marlborough, MA) device in 2015, with an updated generation of device subsequently ratified in 2020 following the PINNACLE-FLX (Protection Against Embolism for Nonvalvular AF Patients: Investigational Device Evaluation of the Watchman FLX LAA Closure Technology) study.
Pulmonary vein (PV) isolation is an effective procedure in patients with paroxysmal atrial fibrillation (AF). For most patients with persistent AF and a subset of patients with paroxysmal AF, however, PV isolation may not be sufficient. Patients with the persistent form are more often beleaguered with comorbidities, which result in a greater degree of structural alterations that contribute to the maintenance of AF. In addition, the atrial activation rate during AF is higher (as evidenced by a shorter AF cycle length) in patients with persistent AF, consistent with a greater degree of electrical remodeling.