Abstract
Objective: Lower heart rate variability (HRV), a measure of autonomic function, has been noted in depression and linked with cardiovascular disease risk. Evidence suggests that some antidepressants, such as tricyclics and SNRIs, adversely impact HRV (Terhardt et al., 2013) while SSRIs appear to have no influence on HRV (Kemp et al., 2010). Desvenlafaxine is a newer SNRI used to treat depression, but there are no published studies on its benefits in chronic depression, or its influence on measure of HRV. The objectives of this pilot investigation were to investigate these issues.
Methods: Twenty-three patients with persistent depressive disorder, who were enrolled in an open-label 8-week trial of monotherapy with desvenlafaxine, were included in this study. HRV was measured at baseline and post-treatment. Differences in HRV parameters were assessed pre-post treatment, as well as between those who responded to treatment (n=15) vs. non-responders (n=8).
Results: Across the sample, HRV measures of time-and frequency-domains significantly decreased over the course of treatment, including SDNN (p<.01), RMSSD (p=.05), RR triangular index (p=.03), as well as total Power (p<.01) and LF/HF Power (p=.03). Significant increases in frequency-domain measures such as HF power (p=.04) were also noted. Further, comparisons between responders and non-responders revealed significant differences in time-domain measures (TINN, p=.04), and overall estimates of HRV (RR triangular index) (p=.02) post-treatment.
Conclusions: The results suggest that treatment response to desvenlafaxine is associated with normalization of sympathovagal balance (HRV). Limitations of this study include small sample size and absence of a control group. Additional investigations are warranted.