The primary purpose of this trial is to demonstrate that the utilization of CartoFinder™ 4D Local Activation Time (LAT) Algorithm may help identify and improve the outcome for the treatment of complex arrhythmias.

Inclusion Criteria:

1. Age ≥ 18 years.

2. Signed the Patient Informed Consent Form (ICF)

3. Scheduled to undergo a clinically-indicated catheter ablation procedure for treatment of

   • Persistent atrial fibrillation (defined as continuous atrial fibrillation that is sustained beyond seven consecutive days).
   • Drug-resistant Atrial Fibrillation. (failed 1 or more class I or III antiarrhythmic drugs) and demonstrating Persistent AF (requiring drugs or electrical shock to terminate)
   • Persistent AF despite prior conventional ablation.

4. Previous procedure permitted but limited to single Pulmonary Vein Isolation (PVI).

5. In AF at the time of the Pre-CartoFinder Map (spontaneous or induced)

6. Able and willing to comply with all pre-, post-, and follow-up testing and requirements.

Exclusion Criteria:

1. Paroxysmal Atrial Fibrillation
2. Continuous AF > 12 months (1-Year) (Longstanding Persistent AF)
3. Cardioversion refractory (The inability to restore sinus rhythm for 30 secs or longer following electrical cardioversion. If a patient does not have documented evidence of being successfully cardioverted (Normal Sinus Rhythm (NSR) > 30 secs), the patient must be cardioverted prior to the ablation procedure. Failure to cardiovert based on the above criteria is considered a screen failure.
4. A complex arrhythmia secondary to a reversible or non-cardiac cause. For example: a complex arrhythmia secondary to electrolyte imbalance or thyroid disease.
5. Left atrial size >55 mm (echocardiography, parasternal long axis view).
6. Significant congenital anomaly or medical problem that in the opinion of the investigator would preclude enrollment in this study.
7. Structural atrial disease such as a prior history of atriotomy from prior atrial surgery, presence of an atrial septal defect, and/or presence of an atrial septal closure patch.
8. History of or current blood clotting or bleeding abnormalities, contraindication to systemic anticoagulation (i.e., heparin, warfarin, dabigatran, or a direct thrombin inhibitor), significant pulmonary disease, cardiac surgeries, unstable angina, uncontrolled heart failure, acute illness or systemic infection, or any other disease or malfunction that would preclude treatment in the opinion of the investigator.
9. Enrollment in an experimental study evaluating another device or drug under investigation.
10. Prosthetic valve
11. Presence of intramural thrombus, tumor or other abnormality / condition that precludes vascular access, catheter introduction or manipulation.
12. Women of child bearing potential whom are pregnant, lactating, or planning to become pregnant during the course of the trial.
13. Presenting contra-indications for the devices used in the study, as indicated in the respective Instructions For Use.