Figure 3.

Factor analysis of abnormal postural change cardiovascular autonomic indices within pSS patients. RR intervals, low frequency RR power (HRV_LF), proportion of successive RR intervals differing by more than 50 ms (pNN50), change in systolic blood pressure on standing (ΔSBP), low frequency systolic blood pressure power (BPV_LF) and the 30/15 ratio were all decreased in patients who have primary Sjögren's syndrome (pSS) relative to control individuals on standing. (a) Three-dimensional scatterplot of rotated (varimax normalized) factor loadings. Factor 1 had the highest loadings for HRV_LF, pNN50 and the 30/15 RR ratio. Factor 2 had the highest loadings for ΔSBP and BPV_LF. Factor 3 had the highest loading for RR intervals during standing. (b) Scatterplot of the HRV factor 1 scores for each pSS patient by the presence of Raynaud's phenomenon. The horizontal bars represent mean scores for each group. Factor 1 scores were significantly lower (more abnormal) in patients without Raynaud's (P = 0.025). (c) Scatterplot of the HRV factor 1 scores (y-axis) versus COMPASS factor 1 scores (x-axis) for each pSS patient. There was a negative correlation that did not quite reach statistical significance (P = 0.08).