Fig. 8

Comparison of HRA estimated by GI, PI, SI, and AI, between 28 CHF patients and 29 healthy volunteers for the clinical data. All HRA indices were calculated based on 5 min ECG recordings. a Bar indicates mean of a specific HRA index and error bar standard error (SE). **p < 0.001. b AUC results are shown as mean ± stardard error (SE)