The Impact of the Atrial Wall Thickness in Less Late-Gadolinium
Enhancement Areas on Atrial Fibrillation Drivers in Persistent Atrial
Background: Some of atrial fibrillation (AF) drivers are found in lesser
late-gadolinium enhancement (LGE) areas, as well as heterogenous ones.
The atrial wall thickness (AWT) has been reported to be important as a
possible AF substrate. However, the AWT and degree of LGEs as an AF
substrate has not been fully validated in humans. Objective: The purpose
of this study was to evaluate the impact of the AWT in lesser LGE areas
on AF drivers. Methods: A total of 287 segments in 15 persistent AF
patients were assessed. AF drivers were defined as non-passively
activated areas (NPAs), where rotational activation was frequently
observed, and were detected by the novel real-time phase mapping (ExTRa
Mapping). Lesser LGE areas were defined as areas with a volume ratio of
the enhancement voxel of <10%. The AWT was defined as the
minimum distance from the manually determined endocardium to the
epicardial border on the LGE-MRI. Results: NPAs were found in 20
(18.0%) of 131 lesser LGE areas where the AWT was significantly thicker
than that in the passively activated areas (PAs) (2.46±0.26 vs.
2.20±0.25 mm, p<0.001). However, NPAs were found in 61
(21.3%) of 287 LGE areas where the AWT was similar to that of the PAs
(2.24±0.24 vs. 2.22±0.25 mm, p=0.58). An ROC curve analysis yielded an
optimal cutoff value of 2.24 mm for predicting the presence of an NPA in
lesser LGE areas. Conclusion: The location of AF drivers in lesser LGE
areas might be more accurately identified by evaluating the AWT.