LA Function After PFA in Paroxysmal AF

This study will leverage ICE to define the acute effects of PFA-PVI on LA and LAA function. The findings will deliver pivotal insights into the functional safety of PFA, clarifying whether a transient stunning effect exists and informing the evolution of peri-procedural anticoagulation management.

Research Objectives

Primary Objective:

To quantify the acute changes in LAA mechanical function immediately following PVI using PFA in patients with paroxysmal AF, as assessed by intraprocedural ICE.

Secondary Objectives:

1. To characterize the acute changes in trans-mitral diastolic flow patterns (E velocity, A velocity, E/A ratio, E deceleration time) as surrogate markers of left atrial pressure and compliance following PFA-PVI. 2. To determine the incidence of new-onset LAA functional stunning, defined as a≥20% reduction in LAA ejection fraction (LAA EF) and/or a clinically significant drop in LAA emptying velocity (LAA Ev) compared with baseline. 3. To explore the correlation between pre-procedural LA strain/LAVI measured by TTE and the degree of acute LAA functional impairment post-PFA.

Research Methods

Study Design A prospective, single-center observational study enrolling consecutive patients with symptomatic, drug-refractory paroxysmal AF undergoing first-time PFA-PVI.

Study Population Inclusion criteria: Adults (≥18 years) with paroxysmal AF in sinus rhythm at procedural onset; Exclusion criteria: Persistent or long-standing AF, prior atrial ablation, significant valvular disease, a history of LAA closure Procedural Protocol All PFA procedures will be performed under deep sedation or general anaesthesia using the FARAPULSETM system (Boston Sci.) according to the current recommendations. To measure the LAA and transmitral velocities, an ICE probe will be positioned transeptally into the LA at the beginning and end of the procedure. For this purpose, the transseptal puncture dedicated to the ablation catheter will be utilized; therefore, the study protocol does not require an additional transseptal puncture

PreProcedural TTE:

Comprehensive TTE within 24 hours before ablation will include LVEF, LA volumes, transmitral inflow velocities (E, A), tissue Doppler velocities (e', a'), and advanced strain analysis (reservoir, conduit, contractile strain).

Intra-Procedural ICE:

1. Mitral Inflow Indices: E velocity, A velocity, E/A ratio, and E deceleration time. 2. LAA Functional Indices: LAA emptying velocity (Ev), filling velocity (Fv), maximal area (Amax), minimal area (Amin), and ejection fraction calculated by the area method:

LAA EF = (LAA Amax - LAA Amin) / LAA Amax × 100%. All measurements will be obtained across three cardiac cycles before and within five minutes after completion of PFA PVI.

Endpoints

1. Primary endpoint: Change in LAA EF and LAA Ev between pre- and post- PFA measurements. 2. Secondary endpoints:

* Variation in diastolic indices; * Proportion of patients demonstrating new-onset LAA stunning * correlations with pre-ablation strain/LAVI parameters.

Data Analysis Continuous variables will be summarized as mean ± SD or median (IQR) based on distribution. Pre/post comparisons will use paired t-tests or Wilcoxon signed-rank tests; binary outcomes will employ McNemar's test. Linear regression models will explore relationships between baseline atrial metrics and magnitude of acute functional decline.