Please click here to obtain permission to reproduce this image.
Click on image to view larger version.
Figure 2 Spatial Heterogeneity of Alternans
Endocardial and epicardial repolarization alternans recorded from 2 patients during atrial pacing at cycle length 500 ms. The magnitude of alternans, defined by Valt and k values, varies between recording electrodes, whereas the noise level remains similar. The horizontal line corresponds to k = 3, which is the threshold for the detection of significant alternans. (A) In the right ventricular endocardium, alternans is present at electrodes 2, 3, 4, 7, and 8. The remaining endocardial electrodes do not manifest alternans and lie adjacent to electrodes with alternans in some cases. (B) In the left ventricular epicardium, alternans is present at electrodes 2, 3, 4, 5, 6, and 8. In the remaining epicardial electrodes, no alternans is detected and some of these electrodes are juxtaposed next to alternating sites.
|
