Correlation of the Arrhythmia Mechanism and Substrate to Ablate Persistent Atrial Fibrillation Study

Pulmonary vein isolation catheter ablation for the treatment of persistent AF (PeAF)or longstanding persistent AF is associated with success rates of 40-50% at one year. Experimental models have shown that AF results in progressive structural changes due to electrical atrial remodeling, where AF burden correlates with atrial fibrosis. The optimal ablation strategy for patients with PeAF is not yet known. There is limited understanding of the critical mechanisms responsible for maintenance of AF in these patients.

In this study ECG body mapping (ECGI) will be used to look for distinct electrical rotors in the atria. Delayed gadolinium enhanced magnetic resonance imaging (DE-MRI) will be used to assess the extent of left atrial fibrosis. In addition to PVI catheter ablation procedure, an ablation strategy guided by the results of the ECGI mapping and DE-MRI will be performed.A C-metahydroxyepherdrine (HED) PET scan will also be done pre-ablation to evaluate left atrial sympathetic denervation and any relationship to the initiation and/or maintenance of AF.

Subjects will be seen at 3 and 6 months after ablation, with 12 lead ECG and 2-week loop monitoring done at each visit.

Inclusion criteria

• Age ≥18 years and ≤ 80 years;
• Symptomatic persistent AF AND clinically indicated for AF catheter ablation
• At least one episode of AF lasting more than 7 days, documented on 12-lead ECG, Holter monitor, 2-week loop monitor or trans-telephonic monitor (TTM) within 12 months of enrollment in the study
• Able to provide informed consent.

Exclusion criteria

• History of previous catheter or surgical ablation for AF
• Presence of intracardiac thrombus
• contraindication to systemic oral anticoagulation therapy
• Subjects with reversible causes of AF
• Antero-posterior left atrial dimension > 60 mm on echocardiography
• Severe valvular disease (mitral/aortic stenosis or regurgitation);
• Subjects that are pregnant or breastfeeding;
• Chronic kidney disease and creatinine clearance <50ml/min.
• Contraindication to MRI Imaging (e.g. permanent pacemaker, metallic implants, etc)