The following conclusions can be drawn from this work

The following conclusions can be drawn from this work:

1. The 2QRS12 reflects better the changes in W in patients with AN than the 2QRS3, at the PW point, and all three ECG systems are not predictive of the HF-W gain. This indicates that there is a nonlinear relationship between changes in W and the ECG, and thus it takes significant W gain for ECG detection. When this stage is reached, the precordial leads are essential for such detection. This may be a reflection of the accumulation of fluid in the dorsal/lateral body plane in patients with AN who are kept supine in critical care units (ie, the gravity effect). Accordingly, we have shown previously a better correlation of the % W and the sum of the QRS complexes from leads V5 and V6 (reflecting the lateral body plane) [ r = 0.65] than the one with the 2QRS12. Moreover, it is revealing that the % W and the sum of the QRS complexes from leads V1 and V2 (reflecting the ventral body plane) [ r = 0.22] did not reach statistical significance (p = 0.26). This overexpression of AN on leads V5 and V6 may be due to the sequestration of fluid in the region of the V5 and V6 leads, leading to further decrease in body resistance. Moreover, such regional fluid accumulation increases the distance of the heart from V5 and V6 recording sites (ie, the Wilson proximity effect). Both of these mechanisms would cause attenuation of surface ECG voltage. The almost complete lack of orthogonality inherent in the limb leads, and the fact that their vectors are expressed in one plane, previously has been commented on.

2. The correlations of the 2QRS6 and 2QRS2 with the 2QRS12 are such that the first two can be considered reflective of the latter. In the control subjects at hospital discharge and in the hemodialysis patients, the 2QRS6 and 2QRS2 reflected better the 2QRS12 than in the patients with AN. This should be expected since in the patients with AN the fluid accumulates especially in places other than the frontal plane, and thus the correlations among ECG systems are attenuated.

3. The similarity in the correlations of the 2QRS2 and 2QRS6 with the 2QRS12 and the correlation with r = 0.86 to 0.93, respectively, between the 2QRS2 and the 2QRS6 are undoubtedly due to the redundancy in the ECG information contained in the frontal ECG leads, an issue that was well-researched and discussed by Rautaharju and colleagues. This is not surprising, since by design such correlations would be expected to be expressed by r values of approximately.