Figure 3

ROC curve of predictive value of orthostatic plasma norepinephrine level for distinguishing responders and non-responders to metoprolol treatment. The y-axis represents the sensitivity to predict the therapeutic response to metoprolol treatment in patients with POTS; the x-axis, the false positive rate (1 = specificity). Area under the curve was 0.785 (95% confidence interval: 0.591 to 0.980, P < 0.05).