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 heart disease (CHD) and is associated with an increased risk for cardiac morbidity and mortality. It is not known whether treating depression will improve medical prognosis in patients with CHD. Depression is also associated with elevated heart rate and reduced heart rate variability (HRV), which are known risk factors for cardiac morbidity and mortality that may explain the increased risk associated with depression. The purpose of this study was to determine whether treatment for depression with cognitive behavior therapy (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 medically comparable nondepressed controls before and after treatment of the depressed patients. Results: Average heart rate and daytime rMSSD (reflecting mostly parasympathetic activity) improved significantly in the severely depressed patients, but remained unchanged in the mildly depressed and the control patients. However, only rMSSD improved to a level comparable to the control patients. None of the remaining indices of HRV showed improvement. Conclusions: The results suggest that treating depression with CBT may reduce heart rate and increase short-term HRV. Thus, CBT may have a beneficial effect on a risk factor for mortality in depressed patients with coronary heart disease. A randomized, controlled study is needed to confirm these findings.