Heart Rate Variability Outcome Measures at Follow-Up.

Data are mean (SD). Analyses adjusted for age, ethnicity, and antidepressant medication use. Statistical notations: (*) significant overall main effect (P<0.0001); (†) significant group effect (P<0.006); (‡) significantly different from control (P<0.05). Abbreviations: SDNN, standard deviation of RR intervals; rMSSD, Root mean square successive difference of RR intervals; HF, log high frequency spectral power (0.15–0.40 Hz); LF, log low frequency spectral power (0.04–0.15 Hz); VLF, log very low frequency spectral power (0.0033–0.04 Hz); PT, log total spectral power frequency.