Arbo JE, Arbo JK, Ford WJH, et al. - Researchers conducted a prospective, observational study examining the utility of heart rate variability (HRV) for evaluation of the severity of illness and poor outcome in the emergency department (ED) patients with sepsis. They evaluated HRV measures were low frequency (LF) signal, high frequency (HF) signal, and deviations in LF and HF signal from age-adjusted reference values. Observations revealed correlation of severity of illness, as defined by sepsis subtype, with reduced LF signal (sepsis: 70.68 ± 22.95, severe sepsis: 54.00 ± 28.41, septic shock: 45.54 ± 23.31), enhanced HF signal (sepsis: 27.87 ± 19.42, severe sepsis: 44.63 ± 27.29, septic shock: 47.66 ± 0.98), frequently negative deviations in LF signal (sepsis: 0.41 ± 24.53, severe sepsis: −21.43 ± 30.09, septic shock −30.39 ± 26.09) and frequently positive deviations in HF signal (sepsis: −1.86 ± 21.09, severe sepsis: 20.07 ± 29.03, septic shock: 23.6 ± 24.17). The predictive value of HRV measures in ED patients with sepsis improves when consideration is given to the influence of age on the baseline HRV signal. Correlation of deviations in LF and HF signal from age-adjusted reference values with individual measures of poor outcome was more consistent than the correlation of LF or HF signal.