Substrate Ablation and Remodelling in Non-paroxysmal Atrial Fibrillation (AF)

Inclusion Criteria: * Ongoing symptoms (European Heart Rhythm Association Class 2 or above) in spite of treatment with rate control medication * Non-paroxysmal atrial fibrillation, as pre-classified as * Persistent AF: AF requiring Electrical/ Chemical cardioversion or that lasting \>7 days. These patients may be in AF or in sinus Rhythm at the time of their initial assessment and/ or at the time of their ablation. * Continuous Persistent AF: These patients are persistently in AF with or without antiarrhythmic drug therapy, as confirmed on a 24 hour Holter. They may have undergone previous cardioversion(s). * Sustained Paroxysmal AF with underlying substrate: Patients with Individual AF episode(s) lasting \>12 hours but less than 7 days plus one or more of the following: * Age \>65 years 21 * Individual AF episode(s) lasting \>24 hours * Significant left atrial dilatation of \>45 mm on Echo (Parasternal Long Axis view) * Obesity (Body Mass Index \>30), and/ or history suggestive of sleep apnoea * Diabetes Mellitus requiring hypoglycaemic drugs and/or Insulin Exclusion Criteria: * Inability or unwillingness to receive oral anticoagulation with warfarin * Previous Ablation procedure for AF * Unwillingness or inability to complete the required follow up arrangements * Presence of long standing persistent AF with continuous AF longer than 12 months. This includes patients in whom sinus rhythm may have been maintained following electrical cardioversion for a period of less than 1 week at a stretch. * Documented typical atrial flutter * Prior prosthetic mitral valve replacement or severe structural cardiac abnormality * Contraindications and/ or prior intolerance to both Amiodarone and Flecainide. * Reversible cause for atrial fibrillation * Known hypertrophic or infiltrative cardiomyopathy