Impact of Box Isolation on Rotors and Multiple Wavelets in Persistent Atrial Fibrillation

Abstract

Background: Additional benefits of posterior left atrial (LA) box isolation (BOXI) over pulmonary vein isolation (PVI) in persistent atrial fibrillation (perAF) have been reported, but the mechanism is still unclear. We evaluated the effects of BOXI on rotors and multiple wavelets in the whole LA. Methods and Results: Twenty patients with perAF (including 12 cases of longstanding perAF) underwent PVI. Real-time phase mapping (ExTRa Mapping) was performed in the whole LA during AF. Subsequently, BOXI was added and re-ExTRa Mapping was performed again at the same site. The nonpassively activated ratio (%NP), the ratio of the form of rotors and multiple wavelets to the recording time, was compared before and after BOXI. After BOXI, the %NP significantly decreased in the anterior wall (from 53±22% to 39±23%, P=0.010), inferior wall (from 51±16% to 34±19%, P=0.001), and LA appendage (from 23±27% to 16±19%, P=0.049). However, there were no significant differences in the septum (49±19% vs. 49±18%, P=0.562) or lateral wall (41±19% vs. 38±15%, P=0.526). Conclusions: BOXI not only reduced the critical mass for maintenance of AF, but also decreased the rotors and multiple wavelets in the anterior wall, inferior wall and LA appendage during perAF.

Clinical impact of eliminating nonpulmonary vein triggers of atrial fibrillation and nonpulmonary vein premature atrial contractions at initial ablation for persistent atrial fibrillation

“…This is consistent with the embryologic origin of the SVC from the sinus venous (as is the sinoatrial node), which explains the arrhythmogenic properties of this structure. LAPW is also reported to be a frequent non‐PV site, and the additional benefit of its isolation over PVI in patients with PEAF has been reported in a previous study 16 . This structure mainly includes the PV antrum and is embryologically derived from the primordial PV 17,18 .…”

Low-Voltage Zones as the Atrial Fibrillation Substrates: Relationship With Initiation, Perpetuation, and Termination

“…A previous study found that PVI plus the isolation of the posterior wall facilitated AF termination, suggesting great contribution of the posterior wall in AF termination ( 27 ). Phase mapping of the LA rotor and wavelets in persistent AF indicated that the isolation of the posterior wall not only reduced the critical mass for maintenance of AF within the posterior wall but also decreased the rotors and multiple wavelets in the other regions ( 28 ). Thus, the LVZ of the posterior wall might play a more important role compared with the anterior wall in the advanced stage of AF.…”

High‐power, short‐duration ablation during Box isolation for atrial fibrillation

“…Previous studies have shown that BOXI in addition to the PVI results in a better outcome than a PVI alone or PVI plus a roof line ablation in patients with persistent AF 4‐12 . The BOXI can capture the triggers, rotors, and low‐voltage areas in the posterior LA, 5 facilitate AF termination and its noninducibility, 5 and decrease the rotors and multiple wavelets on the anterior wall, inferior wall, and LA appendage 20 …”

“…[4][5][6][7][8][9][10][11][12] The BOXI can capture the triggers, rotors, and low-voltage areas in the posterior LA, 5 facilitate AF termination and its noninducibility, 5 and decrease the rotors and multiple wavelets on the anterior wall, inferior wall, and LA appendage. 20…”