While it has been a quarter of a century since we first reported (and almost 30 years since we collected the data) the increase in R wave amplitude in the EKG after hemodialysis, 1 I continue to be perplexed by the finding and therefore I am truly appreciative of the work of Dr. Madias. 2 While I certainly can offer no better explanation, I feel that I must echo the sentiments of Dr. Bernard, “In medicine when we begin to base our opinions on medical tact, on inspiration or a more or less vague sense of intuition on things, we are outside of science and offer an example of fanciful medicine which may involve the greatest of dangers.” 3 A review of our data would tend to lend doubt to Dr. Madias' speculation that the R wave increase is due to alleviation of body fluid overload. Since no increase occurred in patients with the greatest fluid loss (patients 8 and 9, in fact there was a decrease in R wave in patient 9 who experienced the greatest fluid loss). 1 Similarly, patient 16 who gains fluid during his treatment actually develops an R wave increase. In fact, the only significant correlation of R wave increase for our data appears to be with the potassium bath (Table 1, Fig. 1), and while I would not consider myself as astute as Dr. Madias, I am still not totally convinced that the R wave increase is not a manifestation of ischemia since we later found that most of the patients with EKG abnormalities also have thallium defects. 4 Therefore while I am very excited about Dr. Madias' work in this area, I would urge caution at present to the conclusion that the alleviation of fluid volumes is either totally or partially responsible for changes in amplitude of the QRS complex and I look forward to his further work in this area.
Table 1.
Correlations
| Age | Months on Dialysis | Volume Loss During Dialysis | Potassium Bath | R WAVE | |||
|---|---|---|---|---|---|---|---|
| Kendall's tau_b | Age | Correlation coefficient | 1.000 | 0.064 | 0.114 | −0.128 | −0.029 |
| Sig. (2‐tailed) | – | 0.696 | 0.493 | 0.508 | 0.868 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| Months on dialysis | Correlation coefficient | 0.064 | 1.000 | −0.231 | 0.018 | −0.074 | |
| Sig. (2‐tailed) | 0.696 | – | 0.161 | 0.925 | 0.666 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| Volume loss during dialysis | Correlation coefficient | 0.114 | −0.231 | 1.000 | 0.083 | −0.128 | |
| Sig. (2‐tailed) | 0.493 | 0.161 | – | 0.670 | 0.463 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| Potassium bath | Correlation coefficient | −0.128 | 0.018 | 0.083 | 1.000 | −0.394 | |
| Sig. (2‐tailed) | 0.508 | 0.925 | 0.670 | – | 0.054 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| R wave | Correlation coefficient | −0.029 | −0.074 | −0.128 | −0.394 | 1.000 | |
| Sig. (2‐tailed) | 0.868 | 0.666 | 0.463 | 0.054 | – | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| Spearman's rho | Age | Correlation coefficient | 1.000 | 0.130 | 0.106 | −0.152 | −0.044 |
| Sig. (2‐tailed) | – | 0.586 | 0.656 | 0.522 | 0.854 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| Months on dialysis | Correlation coefficient | 0.130 | 1.000 | −0.321 | 0.022 | −0.103 | |
| Sig. (2‐tailed) | 0.586 | – | 0.167 | 0.928 | 0.666 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| Volume loss during dialysis | Correlation coefficient | 0.106 | −0.321 | 1.000 | 0.098 | −0.198 | |
| Sig. (2‐tailed) | 0.656 | 0.167 | – | 0.682 | 0.402 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| Potassium bath | Correlation coefficient | −0.152 | 0.022 | 0.098 | 1.000 | −0.443 | |
| Sig. (2‐tailed) | 0.522 | 0.928 | 0.682 | – | 0.051 | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
| R wave | Correlation coefficient | −0.044 | −0.103 | −0.198 | −0.443 | 1.000 | |
| Sig. (2‐tailed) | 0.854 | 0.666 | 0.402 | 0.051 | – | ||
| N | 20 | 20 | 20 | 20 | 20 | ||
Figure 1.
Normal P‐P plot of regression standardized residual.
REFERENCES
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