This prospective, single-center observational study aims to compare the clinical performance, workflow efficiency, and electrophysiological metrics of two commercially available, high-density multielectrode mapping catheters (Octaray and Optrell) in patients undergoing catheter ablation for complex atrial arrhythmias.

The primary focus is to determine if the real-time vector propagation capabilities of the Optrell catheter combined with V8 software can accurately confirm conduction block across linear ablation lesions without the need for full-chamber activation remapping, which is the current standard of care. A secondary focus will pair-compare the bipolar voltage amplitude distributions recorded by both catheters, given their differing electrode sizes and spacing.

Inclusion Criteria:

• • Age ≥18 years.
• • Documented persistent atrial fibrillation and/or atrial flutter.
• • Undergoing a clinically indicated first-time (de novo) or redo catheter ablation where linear ablation lesion sets (e.g., posterior wall, roof line, lateral mitral line, CTI) are planned or anticipated.
• • Ability to provide written informed consent.

Exclusion Criteria:

• • Paroxysmal or persistent AF where only standard PVI is planned.
• • Mechanical mitral valve.
• • Presence of intracardiac thrombus or contraindication to systemic anticoagulation.
• • Any medical condition or anatomical contraindication that, in the investigator's judgment, precludes safe participation.
• • Pregnant women.