Abstract 15692: Voltage Mapping in Atrial Fibrillation vs Sinus Rhythm: Results From the Mavs Study

Background: Left atrial (LA) scar can be identified with bipolar voltage mapping during sinus rhythm (SR). It is not clear whether the same voltage criteria can be applied during atrial fibrillation (AF). Objective: Aim of this study was to compare voltage maps performed in the same patient both in AF and SR. Methods: Voltage mapping was performed using a 10-pole circular mapping catheter in patients with non-paroxysmal AF undergoing first time RF ablation. For descriptive purposes, the LA was divided in 6 regions: septum, posterior wall (PW), inferior wall (IW), lateral wall, anterior wall, and roof. The threshold for low voltage was 35%. Results: 16 patients (62% persistent AF, 38% longstanding persistent AF) were included in the study. The map density was comparable during AF and SR (mean points per map 551 vs 547, paired t test P = NS). 2 patients displayed normal voltage during both AF and SR. 14 patients showed areas of low voltage during AF, which were still present during SR in 8. All patients with mild “scarring” during AF (n = 4), showed normal voltage during SR. Of the 7 patients with moderate “scarring”, 2 patients showed normal voltage during SR, while in the remaining 5 “scarring” was only mild during SR. 3 patients showed extensive “scarring” during AF, which was only moderate during SR. During AF, areas of low voltage were more commonly observed in the PW (12/14) followed by the IW (6/14) and antero-septum (4/14); while in SR, in the antero-septum (4/8), PW (3/8) and IW (3/8). Interestingly, in all patients both the PW/IW and (less dramatically) the antero-septum showed more “scarring” during AF as compared to SR. Conclusion: Areas of low voltage are more severe and diffuse during AF when compared to SR. When areas of low voltage are detected during AF, they are more commonly seen in the PW, IW and antero-septal areas.