Change in heart rate and heart rate variability during treatment for depression in patients with coronary heart disease

Objective: Major depression is a common problem in patients with coronary h eart disease (CHD) and is associated with an increased risk for cardiac mor bidity and mortality. It is not known whether treating depression will impr ove medical prognosis in patients with CHD. Depression is also associated w ith elevated heart rate and reduced heart rate variability (HRV), which are known risk factors for cardiac morbidity and mortality that may explain th e increased risk associated with depression. The purpose of this study was to determine whether treatment for depression with cognitive behavior thera py (CBT) is associated with decreased heart rate or increased HRV. Methods: Thirty depressed patients with stable CHD, classified as either mildly or moderately to severely depressed, received up to 16 sessions of CBT. The 24 -hour heart rate and HRV were measured in these patients and in 22 medicall y comparable nondepressed controls before and after treatment of the depres sed patients. Results: Average heart rate and daytime rMSSD (reflecting mos tly parasympathetic activity) improved significantly in the severely depres sed patients, but remained unchanged in the mildly depressed and the contro l patients. However, only rMSSD improved to a level comparable to the contr ol patients. None of the remaining indices of HRV showed improvement. Concl usions: The results suggest that treating depression with CBT may reduce he art rate and increase short-term HRV. Thus, CBT may have a beneficial effec t on a risk factor for mortality in depressed patients with coronary heart disease. A randomized, controlled study is needed to confirm these findings .