Cardiac autonomic function and vascular profile in subclinical hypothyroidism: Increased beat-to-beat QT variability.

Background: Patients with subclinical hypothyroidism (SH) may have higher incidence of coronary heart disease and autonomic dysfunction.

Design Of The Study: Prospective case control study.

Aim And Objectives: To evaluate beat-to-beat QT variability and vascular stiffness in patients with SH compared to normal controls.

Effects of Escitalopram on Autonomic Function in Posttraumatic Stress Disorder Among Veterans of Operations Enduring Freedom and Iraqi Freedom (OEF/OIF).

Objective: Posttraumatic stress disorder is a chronic, debilitating condition that has become a growing concern among combat veterans. Previous research suggests that posttraumatic stress disorder disrupts normal autonomic responding and may increase the risk of cardiovascular disease and mortality. Measures of heart rate variability and QT interval variability have been used extensively to characterize sympathetic and parasympathetic influences on heart rate in a variety of psychiatric populations.

Nonlinear indices of circadian changes in individuals with dementia and aggression.

Nonlinear analyses of actigraphy data were utilized to investigate circadian rest-activity system motor control in nursing-home residents with dementia and with/without aggressive behavior (AB). Significant differences observed between groups in measures of approximate entropy (ApEn) and fractal dimension (FD). ApEn and FD are sensitive to detecting and characterizing discrete changes in central motoric control and temporality of behaviors in dementia.

Cardio-respiratory coupling in untreated patients with major depression.

Background: Depressive disorders are known to be associated with higher risks of cardiovascular diseases. Several studies have reported an imbalance within the autonomic nervous system (ANS) as one putative cause. Previous investigations showed decreased cardio-respiratory coupling in depressive patients that were treated with nortriptyline.

Nonlinear relationship between electrodermal activity and heart rate variability in patients with acute schizophrenia.

We investigated to what degree tonic skin conductance levels (SCL) and cardiac autonomic dysfunction are interrelated in schizophrenia. Heart rate variability (HRV) and SCL were simultaneously assessed in 18 unmedicated patients and 18 controls matched for age, sex, weight, and smoking habits. For comparison to prior studies, phasic sympathetic skin responses (SPR) were also recorded.

Reduced cardio-respiratory coupling after treatment with nortriptyline in contrast to S-citalopram.

Objective: Major depressive disorder is associated with increased cardiac mortality. A decrease in vagal modulation related to reduced heart rate variability might contribute to increased mortality among many other factors. We sought to examine the hypothesis that nortriptyline treatment will be associated with a decrease in heart rate variability and coupling between heart rate and respiration compared to treatment with S-citalopram.

Influence of age on linear and nonlinear measures of autonomic cardiovascular modulation.

Background: Age has been identified as an independent risk factor for cardiovascular diseases. In addition, autonomic imbalance toward sympathetic preponderance has been shown to facilitate the occurrence of heart disease. Here, we aimed to assess autonomic modulation of cardiovascular parameters during normal ageing applying well-established linear and novel nonlinear parameters.

The influence of negative mood on heart rate complexity measures and baroreflex sensitivity in healthy subjects.

Background: Decreased cardiac vagal function is linked with increased cardiac mortality and depression is associated with decreased heart rate variability. We have previously shown that the Mood Induction Procedure (MIP) in healthy subjects alters pain perception and thalamic activity during pain perception.

Aim: To study the effect of negative emotion on heart rate variability and complexity measures as well as on baroreceptor sensitivity, as these parameters reflect cardiac autonomic function.

The relation of ventromedial prefrontal cortex activity and heart rate fluctuations at rest.

Recent studies applying functional magnetic resonance imaging have focused on the description of cerebral substrates of changes in cardiac function during diverse autonomic maneuvers or stressful cognitive tasks. These studies might be limited by the indistinguishable neuronal activity due to cognitive processes, which are known to influence autonomic function, and the 'baseline' activity in the central autonomic network. We therefore investigated 26 healthy volunteers in the magnetic resonance scanner to simultaneously obtain functional brain images and RR intervals (intervals between ventricular depolarizations) of the high-resolution electrocardiogram.

Reduced cardio-respiratory coupling indicates suppression of vagal activity in healthy relatives of patients with schizophrenia.

Previous studies have observed reduced vagal modulation in patients with acute schizophrenia and their first-degree relatives, thus suggesting a genetic predisposition. To investigate vagal modulation, we analyzed the coupling between heart rate and breathing as a putative measure of central autonomic function in 19 patients, 19 of their relatives and 19 matched control subjects. The interaction of heart rate and breathing was investigated in all groups applying the non-linear parameter cross-ApEn, indicating the asynchrony between both time series.

Psyche and soma: New insights into the connection.

The interaction of Psyche and Soma are well known and this interaction happens through a complex network of feedback, medication, and modulation among the central and autonomic nervous systems, the endocrine system, the immune system, and the stress system. These systems, which were previously considered pristinely independent, in fact, interact at myriad levels. Psychoneuroimmunology (PNI) is an emerging discipline that focuses on various interactions among these body systems and provides the underpinnings of a scientific explanation for what is commonly referred to as the mind-body connection.

Heart rate variability, QT variability, and electrodermal activity during exercise.

Purpose: Various measures of autonomic function have been developed, and their applicability and significance during exercise are controversial.

Methods: Physiological data were therefore obtained from 23 sport students before, during, and after exercise. Measures of R-R interval variability, QT variability index (QTvi), and electrodermal activity (EDA) were calculated.

Gastric dysmotility in major depression.

Background: Somatic symptoms of the gastrointestinal tract occur frequently in major depressive disorder (MDD) and might be associated with the known autonomic imbalance in the disease. Hence, we have investigated gastric electrical activity in patients suffering from major depression before and after treatment by means of electrogastrography (EGG) to investigate a putative association with either the disease state and its symptoms or its relation to the treatment.

Methods: EGG readings before and after ingestion of a test meal of 27 patients suffering from major depression were recorded before and after treatment with antidepressants and compared with age-matched controls.

Increased QT variability in patients with anorexia nervosa--an indicator for increased cardiac mortality?

Objective: Increased mortality in anorexia nervosa is associated with autonomic dysfunction and prolongation of the QT interval. In this study, we examined the relative importance of repolarization abnormalities and vagal modulation of heart rate. In particular, we hypothesized that patients with anorexia nervosa show increased QT interval variability, particularly since this measure has been shown to correlate with serious cardiac arrhythmias.

Autonomy of autonomic dysfunction in major depression.

Objective: To investigate cardiac autonomic dysfunction in patients with major depressive disorder (MDD). Research in this area has faced several limitations because of the heterogeneity of the disease, the influence of medication, and methodological shortcomings.

Methods: Participants were 75 patients suffering from an acute recurrent episode of MDD and 75 matched controls.

Linear and non-linear measures indicate gastric dysmotility in patients suffering from acute schizophrenia.

Cardiac autonomic dysfunction has been reported in patients suffering from schizophrenia. The aim of the present study was to evaluate gastric electrical activity in unmedicated patients suffering from acute schizophrenia in relation to their symptoms. Electrogastrography was performed before and after test meal ingestion in 26 patients suffering from schizophrenia and 26 matched controls.

Beat-to-beat heart rate and QT interval variability in first episode neuroleptic-naive psychosis.

Introduction: Though increased risk of sudden death in patients with schizophrenia is well-documented, the mechanisms remain unclear. Recent studies report two known risk factors for sudden cardiac death and other arrhythmias in schizophrenia, i.e.

Cardio-respiratory coupling indicates suppression of vagal activity in acute schizophrenia.

Altered amygdala activity in patients with schizophrenia can influence respiratory patterns and consequently cardiovascular parameters. Hence, we examined respiration and heart rate time series complexity as well as coupling of both signals. Electrocardiograms and respiratory signals were obtained from 25 unmedicated patients with schizophrenia and controls.