The purpose of this study is to perform ultra-high density mapping of the left atrium (a chamber of the heart) using the the Rhythmia Mapping System and to determine whether additional ablation in areas of wavefront discontinuities identified by the map will reduce the likelihood of both atrial fibrillation and atrial flutter.

Catheter ablation (CA) is a class 1 indication for patients with symptomatic drug-refractory atrial fibrillation (AF). With standard pulmonary vein isolation (PVI), the success rate ranges from 60-80% in patients with paroxysmal AF. Despite PVI, certain patients have recurrent AF and often require a repeat ablation procedure.

There is no standard ablation strategy for patients who undergo repeat ablation for recurrent AF. The largest randomized trial to date comparing ablation strategies found that the addition of LA roof and mitral isthmus ablation lines or ablation of LA ganglia was no better than standard PVI. Moreover, the addition of ablation lines in the LA, if not complete, may be pro-arrhythmic and lead to the development of LA AFL, which is often more symptomatic that AF itself.

Ultra-high density mapping during sinus rhythm allows for rapid creation of isochronal late activation maps (ILAM) in patients with ventricular tachycardia. To date, creating ILAM of the LA has not been reported and it is not known whether additional ablation in these areas improves freedom from all atrial tachyarrhythmias at 1 year follow-up. Moreover, ablation at the deceleration zones and/or gaps identified using ultra-high density mapping is a promising strategy to improve ablation success and decrease the potential for recurrent AF.

The rationale of the study is two-fold.

1. This study would be the first to report ILAM in the LA and confirm that the diseased LA may behave similarly to the diseased left or right ventricle.
2. Ablation of gaps and/or deceleration zones in the LA would be a novel approach to treat patients with recurrent AF after initial PVI, and if successful, provide another strategy to treat these refractory problems.

Co-PIs:

Hemal Nayak, MD Guarav Upadhyay, MD Andrew Beaser, MD Zaid Aziz, MD

Inclusion Criteria:

• Patients at least 18 years of age
• Re-do AF ablation with history of PVI
• Undergone at least 1 prior ablation

Exclusion Criteria:

• Inability of patient capacity to provide consent for themselves either due to medical or psychiatric comorbidity
• Recent stroke within 6 months of planned procedure
• Inability to take oral anticoagulation

Prospective cohort of patients with AF refractory to prior ablation