FLOW EVAL-AF: FLOW Mapping Electrogram VALidation in Patients With Persistent Atrial Fibrillation

It is hypothesized that initiation and propagation of atrial fibrillation (AF) is dependent, at least in part, on rapid atrial stimulation from focal sources. It is debated whether the mechanism of arrhythmogenesis at these foci is abnormal automaticity, triggered activity, microreentry or rotational reentry. However, after activation emerges from these "driver" sites, fibrillatory conduction ensues resulting in the disorganized conduction pattern of AF. Conventional mapping systems can either achieve high spatial resolution by sequential tachycardia beats following a fixed intra-atrial activation pattern (as in macro reentrant atrial flutter), or high temporal resolution with very low spatial resolution achieved through multielectrode basket catheters. Activation mapping in AF with commercially available mapping systems has been unsuccessful in identifying driver sites because atrial activation patterns change on a beat-to-beat basis precluding the use of sequential mapping approaches, and real-time mapping with basket electrodes lacks sufficient resolution to delineate the complex patterns of conduction.

Electrographic Flow (EGF) mapping (AblaMap®, Ablacon, Inc, Wheat Ridge, CO) is a unique method to assess dominant patterns of intra-atrial conduction during ongoing atrial fibrillation and has been previously described. Recordings from a multielectrode basket catheter are analyzed for electrical activation vectors over sequential 2-second segments during a 60 second acquisition period. Patterns of reproducible vector activation are used to identify driver sources for the atrial fibrillation (AF). Multiple sources are often identified in patients with persistent AF. It is anticipated that substrate modification of these source regions will eliminate the AF drivers and result in a favorable response to catheter ablation as shown in a previously published retrospective analysis.

The FLOW EVAL-AF trial is designed to identify driver sources in patients with persistent or longstanding persistent AF using EGF mapping and describe the activation patterns observed from concomitant high density (HD) mapping of those regions. FLOW EVAL-AF is a prospective, observational, single center pilot trial.

Inclusion criteria

• Scheduled to undergo elective catheter ablation of AF
• History of persistent or longstanding persistent AF
• Able to provide written informed consent prior to the procedure
• Age ≥18 years

Exclusion criteria

• Presence of a permanent pacemaker or other transvenous pacing/defibrillation leads
• Presence of a prosthetic mitral heart valve
• Known reversible causes of AF
• Any cerebral ischemic event (strokes or transient ischemic attacks) which occurred during the 6-month interval preceding the consent date
• History of thromboembolic event within the past 6 months or evidence of intracardiac thrombus at the time of the procedure
• Unable to provide own informed consent