Assessment of Cardiac Autonomic Behavior in Patients With Mood Disorders With a Focus on the Chaos Theory

Mood disorders are strongly associated with changes in cardiovascular function and alterations in Hear Rate Variability (HRV). Fluctuation in heart rate occurs over a wide frequency and demonstrates a broad, irregular variability that suggests that the mechanisms involved in cardiovascular regulation interact in a nonlinear manner. Over the past decade, there has been an increasing emphasis on applying nonlinear methods of analysis to characterize cardiac function, but the studies on the pathophysiology of mood disorders in general still remain under a linear and reductionist perspective. The scarcity of both Brazilian and international studies on the autonomic behavior in mood disorders in general and not only in Major Depressive Disorder, as well as the use of a non-linear reading of the results of this study makes an additional tool of analysis.