Figure 1.
Summary of the method of automated atrial scar mapping and anatomical registration for correlation with voltage distribution. From top to bottom: Intensity of the blood pool (MBP ± SDBP) determined from the area (blue) automatically selected as 1 cm within the LA wall was used to normalize LA wall intensity (ILA), calculated as the maximum intensity along chords (red lines in the second panel) perpendicular to the LA wall. The normalized intensity (NLA) was mapped onto the segmented 3D surface according to a color lookup table (third panel). Measured endocardial voltage points were registered to the MRA segmentation (left first panel). Each electrogram at the annotated point of endocardial contact was assumed to represent a circular region of 2-mm radius. The segmented MRA was divided into cells from a surface mesh, and cells within a 2-mm radius of a voltage point were combined to provide a single mean intensity value (fourth panel) (see text for discussion). Integer intensity levels were plotted against the mean of all colocated voltage measurements. The correlation between mean bipolar voltage and normalized intensity from a single patient is demonstrated (bottom panel). LA = left atrial; MRA = magnetic resonance angiography.