Baroreflex sensitivity is reduced in depression

Depression is independently associated with increased cardiovascular morbidity and mortality, including sudden cardiac death, and this risk is observed even in patients who have been successfully treated for depression. Recent studies have emphasized the importance of impaired baroreceptor sensitivity (BRS) as a predisposing factor for sudden death in patients with manifest cardiac disease. Our objective was to test the hypothesis that BRS is impaired in subjects with depression in remission and with no other cardiac risk factors.

We measured BRS by the sequence method in 36 patients with treated recurrent depression, who were euthymic at the time of study and with no manifest cardiac disease or "conventional" cardiac risk factors, compared with 39 healthy controls. Exclusion criteria included manifest heart disease or any risk factor for IHD (smoking, hypertension, diabetes, hypercholesterolemia, or body mass index >30). Nine subjects were not on any medication, and 22 were taking antidepressants. None of the controls was taking any medication.

BRS was significantly lower in patients than in controls (19.5 [1.78] versus 25.4 [1.69] ms/mm Hg, p = .017). Analysis of covariance, in which age, sex, cholesterol, and body mass index were included, also showed that depression was a significant (p = .027) predictor of BRS. There was no significant difference in BRS adjusted by age and sex between the subjects taking antidepressants compared with those on no medications (p = .40).

These data indicate that BRS is impaired in otherwise healthy patients with depression and may contribute to their increased cardiac risk.