Assessment of heart rate variability as an index of cardiac autonomic modulation in control and depressed persons

ABSTRACT

Under steady state conditions, heart rate displays spontaneous beat-to-beat fluctuation. This fluctuation results from the continuous interaction between the neural or humoral control of cardiovascular function. The fluctuation of heart rate around its mean is called heart rate variability [HRV]. The mechanisms underlying the relationship between depression and cardiac events remain unclear. A disturbance of cardiac Sympathovagal balance is one of the most plausible candidates in depressed patients. To evaluate cardiac Sympathovagal activity in depressed, non cardiac patients. A 24-hour Holter electrocardiogram [ECG] was recorded in 15 newly diagnosed depressed patients and 15 healthy age and sex matched control subjects. Sympathovagal balance was evaluated through time domain parameters of Heart rate variability [HRV]. 15[th] patients with depression disorders were found to have elevated resting heart rate [HR], low heart rate variability [HRV]; decreased Mean NNI, SDNN, rMSSD and pNN50. There is considerable evidence of cardiac autonomic dysregalation. In depressed patients, measured by HRV parameters and these abnormalities may explain the increased cardiac morbidity and mortality rates in these patients