The effect of major depression on heart rate variability in stable coronary artery disease

Objective: Although previous studies have shown that depression is associated with coronary artery disease (CAD), the underlying mechanisms is unclear. A disorders in the autonomic neural system are one of the possible explanations. Heart rate variability (HRV) is identified as changes on sinus rate which gives idea both sympathetic and parasympathetic balance. Low HRV is an indicator for increased sympathetic and deficient parasympathetic tone. Previous studies have shown that lower HRV is associated with adverse cardiovascular outcomes. Disorders of the neurohormonal system can accelerate the CAD with several mechanisms such as changing cardio autonomic tone, triggering the coagulating and inşammatory processes which is related to mental stress, and extending the QT interval. The aim of the study is to evaluate the effect of the major depression on HRV parameters in patients with stable CAD.

Method: Patient group consists of 65 CAD patients, who have major depression diagnosis according to DSM-IV-TR and control group consists of 54 CAD patients who don’t have major depression. Montgomery- Asberg depression evaluation measurement (MADRS) is used to detect the degree of the disorder on the patients who have depression diagnosis. To evaluate HRV, 24 hour Holter electrocardiography follow up is used.

Results: The average age was found 59.9±10.4 for the patient group and 59.2±10.2 for the control group (p=0.715). The sociodemographic characteristics are found similar for patient and control groups. When we compared HRV parameters between patient and control group, we found that RR, SDNN, SDNN index, SDANN, pNN50, RMSSD values were significantly lower in patient group. MADRS score was correlated with pNN50 value in patient group (r= -0.318 and r= -0.307, p<0.05). Linear regression analyses demonstrated that MADRS scores were independent predictors of pNN50 value (β= -0.375, p<0.001).

Conclusion: In our study, HRV parameters were significantly lower in patient group. MADRS score was correlated with pNN50 value in patient group. Moreover, MADRS scores were independent predictors of pNN50 value.