STrategies for Catheter Ablation of peRsistent Atrial Fibrlllation

Inclusion Criteria: 1. Patients 18 years of age or older 2. Patients undergoing first-time ablation procedure for AF 3. Patients with persistent AF defined as a sustained episode more than 3 months but less than three years 4. Patients with symptomatic AF - symptomatic patients are those who have been aware of their AF at any time within the last 5 years prior to enrolment. Symptoms may include, but are not restricted to, palpitations, shortness of breath, chest pain, fatigue, left ventricular dysfunction, or other symptoms or any combination of the above 5. Patients whose AF has been refractory to at least one antiarrhythmic drug 6. At least one episode of AF must have been documented by ECG, holter, loop recorder, telemetry, trans-telephonic monitor or implanted device within the last 2 years from enrolment 7. Patients must be able and willing to provide written informed consent to participate in the study Exclusion Criteria: 1. Patients with paroxysmal AF (no episodes lasting \> 7 days) 2. Patients with early persistent AF, sustained episode ≤ 3 months 3. Patients with very long lasting persistent AF (episodes lasting \> 3 years) 4. Patients with CHA2DS2-VASc score of 0. 5. Patients for whom cardioversion or sinus rhythm will never be attempted/pursued 6. Patients with AF felt to be secondary to an obvious reversible cause 7. Patients with contraindication to oral anticoagulation or systemic anticoagulation with heparin 8. Patients with left atrial diameter \> 60 mm in the parasternal long axis view 9. Patients who are pregnant