DISPARITY-AF is a prospective, single-center, observational registry designed to characterize the sex-based disparities in the electrophysiological substrate driving Atrial Fibrillation (AF). While standard Pulmonary Vein Isolation (PVI) is the cornerstone of AF ablation, women consistently experience lower long-term success rates. This study tests the hypothesis that women harbor a significantly higher burden of unmapped, extra-pulmonary vein (extra-PV) AF initiation sites compared to men.

In 100 consecutive patients undergoing first-time PVI, comprehensive biatrial repolarization mapping will be performed using programmed electrical stimulation (PES) to measure the atrial effective refractory period (AERP) in multiple atrial sites immediately after successful PVI. All mapping systems and multielectrode catheters utilized in this study are clinically approved and used routinely in our center. Identified steep repolarization gradients (SRGs) and AF initiation sites will be documented but not ablated. Patients will undergo intensive 1-year clinical follow-up to test the secondary hypothesis that patients with untreated extra-PV SRG/AF initiation sites have a significantly higher rate of AF recurrence.

Inclusion Criteria:

• Age 18 years or older.
• Male or Female sex.
• Symptomatic paroxysmal or persistent AF indicated for a first-time catheter ablation.
• Ability to provide written informed consent.

Exclusion Criteria:

• Prior catheter ablation for AF or surgical MAZE.
• Long-standing persistent AF (>12 months).
• Presence of intracardiac thrombus or contraindication to systemic anticoagulation.
• Pregnant women and patients not able to provide an informed consent

The study requires 50 male patients and 50 female patients.