Assessment of acute EIVM effect by EAM
LA bipolar voltage mapping was performed before and immediately after
EIVM by using the duodecapolar PentaRay catheter and the CARTO3 v6 or v7
EAM system (Johnson & Johnson, Irvine, CA) with the Tissue Index
Proximity tool activated to ensure tissue contact for each recorded
electrogram. The rhythms during which voltage mapping was performed was
SR, AF or PLMAF before EIVM and SR, AF or PLMAF after EIVM. For patients
in whom EIVM acutely changed the atrial rhythm (n=8 [29%],
including AF to PMLAF, n=4; PMLAF to sinus rhythm, n=3; PMLAF to
roof-dependent flutter, n=1), we performed no specific correction to
take into account the correlation of electrogram amplitude to the type
of atrial rhythm. The scar area in the VOM region was defined as the
area with bipolar voltage <0.05 mV. The PV was excluded from
scar area analyses because PV volume acquisition may vary substantially
between procedures. The scar area was delineated by using the “Area
Measurement” tool of the CARTO3 software. Scar areas in the VOM region
before and immediately after EIVM were compared to assess the acute EIVM
effect (Figure 1).