Pulmonary Veins Function as Echo Chambers in Persistent Atrial Fibrillation: Circuitous Re-Entry Generates Outgoing...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Pulmonary vein isolation (PVI) is the standard treatment for persistent atrial fibrillation (PeAF).
• However, the substrate for PeAF extends beyond the pulmonary veins (PVs).

Purpose of the Study:

• To investigate the mechanism of outgoing wavefronts (WFs) originating from the PV sleeves during PeAF.
• To understand the role of PV sleeves in sustaining PeAF.

Main Methods:

• Recruited 11 patients undergoing first-time PeAF ablation.
• Utilized a 64-electrode catheter and inverse mapping to reconstruct electrograms on the PV surface.
• Analyzed phase maps to identify and classify wavefront activity within PV sleeves.

Main Results:

• PVs generated outgoing WFs at a frequency of 3.7 s⁻¹ during PeAF.
• Circuitous macroscopic re-entry was the dominant mechanism (2.7 s⁻¹), initiated by incoming WFs in 80% of cases.
• The ratio of outgoing to incoming WF frequency (R) was > 1 in 6 of 11 PVs, indicating amplification.

Conclusions:

• PV sleeves generate electric activity in PeAF mainly through circuitous re-entry.
• PVs function as
• echo chambers
• amplifying and sustaining atrial fibrillation rather than acting as primary drivers.