The aim of this work is to study heart rate variability (HRV) as a measure of autonomic imbalance in patients with major depression and also to see whether these measures can be corrected by treatment.
Patients and methods
Four groups (10 participantseach) were chosen: group I-A and group I-B (physically healthy patients with major depression), group II (mentally healthy postmyocardial infarction patients), and group III (physically and mentally healthy comparison individuals). HRV was measured using a nonlinear time domain measure (point-wise correlation dimension, PD2). Depression rating was done using the Montgomry–Asperg depression rating scale. Both major depression groups were followed up for 3 months during which they were assigned to different treatment modalities (either medication alone, group I-A, or medication combined with physical exercise, group I-B).
Measures of HRV were comparable in patients with major depression and those in the postmyocardial infarction period but significantly lower than those of healthy individuals. After 3 months, both groups of patients with major depression showed significant improvement in their depression rating scores but only those who were assigned to the physical exercise showed significant improvement in their HRV measures.
Autonomic cardiac imbalance in major depression is comparable to that present in mentally healthy cardiac patients themselves. Whether this imbalance is a state marker of depression or not is still debatable, and giving special concern to reverse it is of utmost importance in decreasing cardiac mortality and morbidity in major depression.