AUTONOMIC CORRELATES OF ANTIDEPRESSANT TREATMENT USING HEART-RATE-VARIABILITY ANALYSIS

Objective: To assess the 24-hour temporal-domain heart-rare variabilit y correlates of treatment with fluoxetine or doxepin for depression. M ethod: A randomized evaluation of fluoxetine and doxepin measured a 50 % change in the Hamilton Depression Rating Scale (HDRS) score as a res ponse to therapy and was correlated with measures of standard deviatio n of the mean of all 5-minute segments of normal electrocardiographic R-R intervals (SDANN), standard deviation of all normal R-R intervals (SDNN), roof mean square of successive differences in R-R intervals (r -MSSD), and percentage difference between adjacent normal R-R interval s that are greater than 50 msec (pNN50) from 24-hour electrocardiogram (ECG) rapes. Results: Ten out of 14 patients responded. Response was associated with an increase in SDANN of 17% (p < 0.05). Nonresponse wa s associated with a 17% decrease in SDANN and a 22% decrease in SDNN ( both P < 0.05). No other measures correlated with therapeutic response . No heart-rate variability (HRV) differences between the 2 drug thera pies were observed. Conclusion: Twenty-four-hour HRV measures may be u seful in assessing response to antidepressant therapy.