Cardiac Autonomic Dysfunction in Patients with Schizophrenia and Their Healthy Relatives – A Small Review

Abstract

The majority of excess mortality among people with schizophrenia seems to be caused by cardiovascular complications, and in particular, coronary heart disease. In addition, the prevalence of heart failure and arrhythmias is increased in this population. Reduced efferent vagal activity, which has been consistently described in these patients and their healthy first-degree relatives, might be one important mechanism contributing to their increased cardiac mortality. A decrease in heart rate variability and complexity was often shown in unmedicated patients when compared to healthy controls. In addition, faster breathing rates, accompanied by shallow breathing, seem to influence autonomic cardiac functioning in acute unmedicated patients substantially. Moreover, low-physical fitness is a further and independent cardiac risk factor present in this patient population. Interestingly, new studies describe chronotropic incompetence during physical exercise as an important additional risk factor in patients with schizophrenia. Some studies report a correlation of the autonomic imbalance with the degree of positive symptoms (i.e., delusions) and some with the duration of disease. The main body of psychiatric research is focused on mental aspects of the disease, thereby neglecting obvious physical health needs of these patients. Here, a joint effort is needed to design interventional strategies in everyday clinical settings to improve physical health and quality of life.

Biofeedback to treat anxiety in young people at clinical high risk for developing psychosis

“…12 There is evidence for autonomic system dysfunction as evaluated by low HRV, low vagal activity and poor autonomic adaptability and reactivity in people with schizophrenia. [30][31][32][33] This is similarly observed in anxiety disorders, although more pronounced in psychosis. 34 A simple and non-invasive way to impact autonomic activity is with HRV biofeedback, a tool that can increase HRV, mainly through the regulation of breathing in response to external feedback to influence associated autonomic reactions.…”

“…Low HRV indicates increased sympathetic nervous system activity and is characteristic of many psychiatric and general medical conditions . There is evidence for autonomic system dysfunction as evaluated by low HRV, low vagal activity and poor autonomic adaptability and reactivity in people with schizophrenia . This is similarly observed in anxiety disorders, although more pronounced in psychosis .…”

Association of Resting Heart Rate and Blood Pressure in Late Adolescence With Subsequent Mental Disorders

“…A bnormalities in cardiac autonomic functioning have been observed in a range of psychiatric disorders. 1 For example anxiety disorders, 2 depression, 3 and schizophrenia 4,5 have been associated with reduced beat-to-beat variation in heart rate, indicating reduced parasympathetic activity.…”

Prolonged QT Interval in Neurodevelopmental Rat Model of Schizophrenia

“…hERG gene) related to potassium channels and their regulation. Other mechanisms might be associated with alteration of dopamine D2 receptor signalling in the heart or with imbalance of autonomic nervous system, particularly with reduced efferent vagal activity [6] leading to abnormalities in heart rate variability [7].…”