High-resolution MRI of Atrial Fibrillation Patients Prior to Focal Impulse and Rotor Modulation (FIRM) Ablation

The project will be a prospective trial involving patients consented for a clinically indicated atrial fibrillation (AF) ablation using FIRM mapping. The purpose of the study is to collect additional information before, during, and after the ablation procedure. All patients will undergo a contrast-enhance MRI scanning with gadolinium-based contrast agent prior to the procedure as it provides a 3-dimensional image of both the left atria and right atria. The primary endpoint of this study will be the presence or absence of a correlation between micro-anatomic fibrotic tracks, determined by a combination of atrial wall thickness, and local scar and fibrosis, and sites of FIRM map indicated rotor activity. Medical information will also be collected after the patients 2nd, 3rd and 6 month standard of care doctor visits. There are no additional risks associated with this protocol over and above that of the standard risk of atrial fibrillation ablation with FIRM, and those associated with the standard risk of magnetic resonance imaging with gadolinium contrast agent, but there is a small risk of the loss of confidentiality when participating in an observational study. The potential benefits includes the possibility of greater understanding of the patient's specific disease state.

Inclusion criteria

• Patients with symptomatic paroxysmal or persistent atrial fibrillation undergoing clinically-indicated ablation procedure employing FIRM mapping with pre-operative MRI.
• Subjects must be at least 18 years of age.

Exclusion criteria

• LAA thrombus present on pre-procedure TEE
• Unable to undergo MRI imaging
• Unable to receive gadolinium contrast.