Acute Changes in Left Atrial Appendage Flow Velocity During Pulsed Field Ablation: An Intraprocedural Intracardiac Echocardiography Study

Background Despite the close anatomical relationship between the left pulmonary veins (PVs) and the left atrial appendage (LAA), acute changes in LAA flow during pulsed field ablation (PFA) remain poorly characterized. Objectives To characterize acute intraprocedural changes in LAA flow and transmitral filling during PFA for atrial fibrillation (AF) using paired intracardiac echocardiography (ICE). Methods Patients with paroxysmal or persistent AF undergoing PFA were prospectively enrolled if they were in sinus rhythm at the beginning of the procedure. ICE was performed immediately before and after PFA to assess LAA emptying velocity (LAAEv), LAA filling velocity (LAAFv), transmitral E- and A-wave velocities, and E-wave deceleration time (EDT). Paired pre-to-post PFA changes were assessed, followed by a sensitivity analysis using analysis of covariance (ANCOVA) and exploratory subgroup analyses. Results Among 98 patients, LAAEv increased from 35.45 to 40.00 cm/s immediately after PFA (estimated paired increase, 4.95 cm/s; 95% CI, 2.35–7.80; P<0.001), while LAAFv increased by 4.36 cm/s (95% CI, 1.81–6.91; P=0.001). E-wave velocity increased by 8.69 cm/s and EDT decreased by 31.73 ms (both P<0.001), whereas A-wave velocity did not change significantly (P=0.08). In the ANCOVA model, changes in heart rate, systolic blood pressure, and vasopressor use were not significantly associated with changes in LAAEv. A marked acute reduction in LAAEv (≥20%) occurred in 12 patients (12.2%). No significant subgroup interactions were observed. Conclusions LAA flow velocities increased acutely after PFA, accompanied by changes in transmitral filling, although a minority of patients showed a marked acute reduction in LAA emptying.