Heart rate variability in patients with major depression.

We have previously reported decreased heart rate variability upon standing in panic disorder patients compared with controls. In this study, we extend our report to include patients with major depression (n = 19). Compared to normal controls (n = 20) and panic disorder patients (n = 30), there was no significant difference in the immediate changes in heart rate upon standing in the depressed group. The standing heart rate variability (R-R variability) was significantly lower in panic disorder patients compared to both normal controls and depressed patients as indicated by the corrected standard deviations, the corrected mean consecutive difference, the corrected standard deviation of the mean consecutive difference of the R-R intervals, and the high frequency variability in successive R-R intervals, suggesting an increased vagal withdrawal in panic disorder patients, especially upon standing. There was no significant difference in any of the heart rate variability measures between depressed patients and normal controls.