ABSTRACT
A large body of evidence has documented shortened life expectancy in patients with schizophrenia. It has been assumed that suicides, accidents, and cardiovascular disorders are the main reasons for the excess of premature and sudden deaths among patients with schizophrenia. In general, nearly all HRV measures reflect mainly vagal modulation at the level of the heart. HRV is the physiological phenomenon of variation in the time interval between heartbeats and it is determined by measuring the variation in the beat-to-beat interval. A concept that is closely connected to that of variability is complexity. The evaluation of baroreflex sensitivity is an established tool for the assessment of autonomic control of the cardiovascular system. The baroreflex is one of the body's homeostatic mechanisms to maintain blood pressure at nearly constant levels. The baroreflex provides a negative feedback loop in which an elevated blood pressure reflexively causes the heart rate to decrease.
