Author + information
- Phyllis K Stein, PhDa ()
Fauchier et al., in their recent report (1), have made an important contribution to the use of heart rate variability for risk stratification. However, I have some concerns about the data as presented. Of concern in Table 3 in their article is the report that SDANN was greater than SDNN in both of the groups with outcomes. This reflects either a typographic or methodologic error. Also, in Table 3, mean rmsSD is much higher in the group with sudden death, whereas ln HF is not different between the groups. This raises the possibility that the high values for rMSSD are associated with abnormal, nonrespiratory HRV, a phenomenon we have termed “erratic sinus rhythm.” This possibility can be examined by looking at the distribution of power in a power spectral plot or by plotting heart rate tachograms and examining the pattern of heart rate changes. Finally, in Table 3, Fauchier et al. (1)give values for ln VLF power as computed by the Oxford scanner. In each case, VLF power is even lower than HF power. Because VLF power is ordinarily greater than LF power, which is greater than HF power, it is clear that the Oxford scanner values for VLF are not comparable to those reported by others who use research software. Similarly, the relationship between this value of VLF and total power, as described in the second paragraph of the discussion, while conceivably valid for a 10-min window, cannot be compared with the standard for 24-h–based total power, which reflects primarily circadian rhythms, and cannot be obtained in a 10-min window. The aforementioned tachograms, incidently, will also reveal the presence of periodic respiration.
- American College of Cardiology