Heart rate variability and autonomic dysfunction in SSPE

Autonomic nervous system involvement in subacute sclerosing panencephalitis was studied in 29 patients by analysis of heart rate variability and compared with a control group which consisted of 20 age- and sex-matched healthy subjects. Holter recordings for 24 hours were obtained, and all recordings were analyzed using time-domain parameters. The patients with subacute sclerosing panencephalitis were found to have significantly lower values of standard deviation of all normal sinus intervals and triangular index when compared with the control group. Of 23 patients who had regular follow-up, 15 died in a period ranging from 1 to 13 months. Twelve of these patients had heart rate variability parameters lower than normal, but no significant difference was observed between the heart rate variability values of patients who survived or died. Also, there was no association between brain magnetic resonance imaging findings and heart rate variability indices. It is concluded that patients with subacute sclerosing panencephalitis have autonomic dysfunction; and this was thought to be mainly due to central involvement.     

Heart rate variability in bipolar mania and schizophrenia

Background

Autonomic nervous system (ANS) dysfunction and reduced heart rate variability (HRV) have been reported in a wide variety of psychiatric disorders, but have not been well characterized in bipolar mania. We recorded cardiac activity and assessed HRV in acutely hospitalized manic bipolar (BD) and schizophrenia (SCZ) patients compared to age- and gender-matched healthy comparison (HC) subjects.

Method

HRV was assessed using time domain, frequency domain, and nonlinear analyses in 23 manic BD, 14 SCZ, and 23 HC subjects during a 5 min rest period. Psychiatric symptoms were assessed by administration of the Brief Psychiatric Rating Scale (BPRS) and the Young Mania Rating Scale (YMRS).

Results

Manic BD patients demonstrated a significant reduction in HRV, parasympathetic activity, and cardiac entropy compared to HC subjects, while SCZ patients demonstrated a similar, but non-significant, trend towards lower HRV and entropy. Reduction in parasympathetic tone was significantly correlated with higher YMRS scores and the unusual thought content subscale on the BPRS. Decreased entropy was associated with increased aggression and diminished personal hygiene on the YMRS scale.

Conclusion

Cardiac function in manic BD individuals is characterized by decreased HRV, reduced vagal tone, and a decline in heart rate complexity as assessed by linear and nonlinear methods of analysis. Autonomic dysregulation is associated with more severe psychiatric symptoms, suggesting HRV dysfunction in this disorder may be dependent on the phase of the illness.     

Spectral change in heart rate variability in response to mental arithmetic before and after the beta-adrenoceptor blocker,carteolol

Spectral analysis of heart rate fluctuation was evaluated before and after administration of carteolol, a non-selective-adrenoceptor-blocker, to investigate the neural regulatory mechanisms underlying the haemodynamic changes induced by mental stress. Mental stress increased blood pressure and heart rate, with an increased low frequency band, and low frequency/high frequency ratio of the power spectral analysis which are indices of sympathetic activity. Carteolol did not change basal and pre-mental stress measurements of blood pressure, heart rate and spectral density. However, carteolol altered the response to mental stress with a decrease in spectral density of the low frequency band and low frequency/high frequency ratio, and an increase in the high frequency component. These results confirm that mental stress elevates blood pressure by activating the sympathetic nervous system, and suggest that blockade of the-adrenoceptor attenuates the pressor response by preventing the autonomic responses to mental stress.     

Heart rate variability and vagal tone in schizophrenia: A review

Recent heart rate variability (HRV) research has identified diminished levels of parasympathetic activity among schizophrenia patients. Over two dozen empirically-based studies have been published on this topic; primarily over the last decade. However, no theoretical review appears to have been published on this work. Further, only one empirical study has evaluated HRV research findings in the context of documented hypothalamic-pituitary-adrenal axis hyperactivity in schizophrenia. HRV research indicates that no abnormalities exist in the initial sympathetic stress response of schizophrenia patients. However, evidence has consistently demonstrated that patients exhibit a diminished capacity to recover from a stress response as a result of deficits in parasympathetic activity. Moreover, this diminished parasympathetic nervous system (PNS) response, also known as decreased vagal tone, has been found to relate to increased symptom severity. Although these findings may cause speculation that the observed vagal tone disruption merely results from anxiety produced by the presence of positive symptomology, additional studies have identified similar parasympathetic dysfunction among nonpsychotic relatives of individuals with schizophrenia. We posit that the resulting sympathovagal imbalance leads to an overall sympathetic dominance despite the fact that sympathetic nervous system activity is not abnormally elevated among patients. Implications are discussed within the context of the diathesis-stress/vulnerability-stress model, including the potential for identifying a mechanism of action by which environmental stressors may contribute to triggering first-episode psychosis.     

Heart rate variability in neonatal patients with seizures

Objective

Seizures are frequently observed in neurological conditions affecting newborns. Since autonomic alterations are commonly associated with neonatal seizures (NS), we investigated the utility of heart rate variability (HRV) indexes of cardiac autonomic regulation for NS detection.

Heart rate variability in patients with major depression

We have previously reported decreased heart rate variability upon standing in panic disorder patients compared with controls. In this study, we extend our report to include patients with major depression (n = 19). Compared to normal controls (n = 20) and panic disorder patients (n = 30), there was no significant difference in the immediate changes in heart rate upon standing in the depressed group. The standing heart rate variability (R-R variability) was significantly lower in panic disorder patients compared to both normal controls and depressed patients as indicated by the corrected standard deviations, the corrected mean consecutive difference, the corrected standard deviation of the mean consecutive difference of the R-R intervals, and the high frequency variability in successive R-R intervals, suggesting an increased vagal withdrawal in panic disorder patients, especially upon standing. There was no significant difference in any of the heart rate variability measures between depressed patients and normal controls.     

Heart rate variability in patients with untreated epilepsy.

BACKGROUND: Several studies have reported reduced heart rate variability (HRV) in patients with chronic epilepsy under treatment with antiepileptic drugs. This impairment in cardiac autonomic control might be of relevance in relation to the risk of sudden unexpected death in patients with chronic refractory epilepsy. Little information is, however, available on HRV in untreated patients with newly diagnosed epilepsy. METHODS: We used spectral analysis to assess HRV based on 24h ambulatory EKG recordings in 22 consecutive untreated patients with epilepsy (15 with localization-related, 4 with generalized idiopathic and 3 with undetermined epilepsy). The HRV in these patients was compared with 22 age and sex matched healthy controls. RESULTS: When analysing the full 24h recordings, there were no significant difference between the patients and the controls in any of the analyzed measures of HRV: standard deviation of RR-intervals (P=0.191), total power (P=0.170), very low frequency power (P=0.329), low frequency power (LF) (P=0.161), high frequency power (HF) (P=0.186) and the LF/HF ratio (P=0.472). The results were very similar for daytime and nighttime recordings. CONCLUSION: Our results suggest that there is no major effect of epilepsy as such on HRV in patients with untreated epilepsy. It should be emphasized that this study assessed newly diagnosed patients and that the results may not be applicable to patients with chronic epilepsy.     

Heart rate variability in patients with untreated Parkinson's disease

The aim of this study was to evaluate cardiovascular responses as a marker of autonomic nervous system (ANS) disturbances in patients with untreated Parkinson's disease (PD) and to assess the relationship between them and the clinical characteristics of PD. The ANS functions were investigated in 50 patients with PD and 55 healthy subjects by measuring standard cardiovascular autonomic reflexes and heart rate variability (HRV) at rest using spectral analysis (the autoregressive model and the fast Fourier transformation), the percentage of the counts of beat-to-beat variation greater than 50 ms and the fractal dimension. Significantly attenuated HRV and deficient blood pressure reaction to tilting were found in the PD patient group. The patients with hypokinesia/rigidity as the initial symptom of PD had a more pronounced HRV deficit than those with tremor onset. Untreated PD patients suffer significant failure in cardiovascular nervous system regulation, and in patients with hypokinesia/rigidity as their initial disease manifestation the risk of this ANS dysfunction is high. However, in the early stages of PD these changes did not reach significance at individual level.     

Heart rate variability in patients with frontal lobe epilepsy

ObjectiveTo identify autonomic dysregulation in frontal lobe epilepsy (FLE).MethodsWe studied 14 male and 11 female subjects with FLE and an equal number of matched healthy control subjects. Lead I electrocardiograms were obtained for 5 min in the interictal state during daytime. Frequency-domain analysis of heart rate variability was performed and the data subsequently converted to heart rate interval and high frequency (HF; 0.15–0.45 Hz) power which representing vagal or parasympathetic regulation, as well as low frequency (LF; 0.04–0.15 Hz) power and LF/(HF + LF) expressed in normalized units (LF%) (considered to mirror sympathetic regulation). Differences in data between groups were compared using t-test.ResultsThe epilepsy group had a lower mean heart rate interval and a lower high frequency power.ConclusionsPatients with FLE have interictally faster heart rates, attributed to lower parasympathetic drive, which may contribute to the higher incidence of sudden death that is seen in this group of patients. This suggests that the mechanism of decreased HRV in patients with FLE is probably different from that in patients with temporal lobe epilepsy.     

Differential pattern of heart rate variability in patients with schizophrenia

The cardiac autonomic dysfunction has been reported in patients with schizophrenia. Heart rate variability (HRV) provides non-invasive indices of cardiac autonomic modulation. This study examined whether patients with schizophrenia may show a distinctive pattern of HRV compared to healthy controls. Nine measures of time, frequency and complexity domains were extracted from 5-min resting evaluation of HRV in 30 unmedicated patients with schizophrenia and 30 age- and gender-matched controls. In addition to inferential statistics, a hierarchical clustering (HC) was used to examine difference in the interrelationships among HRV measures between the two groups. Multivariate analysis of variance revealed a significant group effect. Significantly lower sample entropy (SampEn) and a trend towards a higher ratio of low- to high frequency (LF/HF) were observed in the schizophrenia group. In the results of HC using Ward's method, SampEn co-clustered with LF/HF ratio in patients with schizophrenia compared to the separation of LF/HF ratio in healthy controls. In concert with decreased parasympathetic activity, low complexity of heart rate dynamics may reduce adaptability of cardiovascular system to changes in internal or external environment, thus increasing the risk of cardiovascular events. Diverse HRV measures combined in a multivariate fashion appear to be useful in understanding the pattern of neurocardiac modulation in patients with schizophrenia.     

Heart rate variability in Parkinson's disease patients treated with tolcapone

Following the introduction of tolcapone, a potent, reversible Catechol-O-methyltransferase (COMT) inhibitor, it has been possible to optimise the management of Parkinson's disease (PD) patients in chronic Levodopa (L-dopa) therapy. The interaction between tolcapone and the endogenous metabolism of catecholamines points to a possible influence on autonomic cardiovascular function.Cardiovascular reflexes have been analysed in a group of seven PD patients (four males, three females; mean age 69.7years, mean disease duration 14.1years) by means of the heart rate variability (HRV) method using a continuous 24-h ECG (ECGD), before and after six months of treatment with tolcapone (in addition to L-dopa).We have observed no statistically significant differences in HRV parameters, nor any changes in the incidence of hyperkinetic and hypokinetic arrhythmias, which suggest that autonomic cardiovascular function in PD patients is not influenced by six months of treatment with tolcapone.     

癫癎患者发作间期心血管自主神经功能与心率变异性

目的　探讨癫　患者发作间期心血管自主神经功能与心率变异性（ＨＲＶ）的变化。方法　５１例癫　患者根据标准心血管自主神经功能试验结果分为阳性（ＡＮＦＴ＋）组及阴性（ＡＮＦＴ－）组,与正常对照组３６例对比,进行ＨＲＶ分析。结果　癫　患者发作间期心血管自主神经功能异常率为４５．１％,且病程越长异常率越高。癫　患者在ＨＲＶ时域分析及非线性定量分析指标上均较对照组降低,且以　ＡＮＦＴ＋组患者最明显。ＨＲＶ直方图、散点图亦有特征性改变,以ＡＮＦＴ＋组患者最为显著。结论　癫　患者发作间期心血管自主神经功能存在紊乱现象,这种现象可能与癫　患者的猝死发生有关,ＨＲＶ是测定这一变化的敏感方法。     

癫

目的探讨癫     

Heart rate variability and autonomic function tests in HIV positive individuals in India

Supine heart rate variability (HRV) and autonomic tests were carried to determine whether autonomic activity was affected in HIV positive patients. The pressor response following handgrip and cold pressor test was blunted in HIV+ patients, and the degree of dysfunction correlated with CD4 cell counts. The extent of autonomic impairment was mild and subclinical.     

Heart rate variability in patients with essential tremor: A cross sectional study

ObjectiveTo investigate heart rate variability (HRV) in patients with Essential Tremor (ET) in comparison with patients with Parkinson's Disease (PD).MethodsThis is a cross sectional control study including 10 patients with ET, 10 patients with PD and 10 age-sex-matched controls. In patients and controls, we measured the components of HRV analysis in the frequency domain during a daytime period of 12-h. Selected HRV variables were low-frequency (LF) and high-frequency (HF), conventionally considered to be influenced by the sympathetic system and the parasympathetic system respectively.ResultsHRV variables, in patients with ET, were significantly different from those detected in PD patients and similar to those of controls while in PD patients, they were significantly different from those of controls. At cut off level of 654 ms², LF component correctly distinguished ET patients versus PD with sensitivity, specificity, PPV and accuracy of 100%. By contrast, at cut off level of 737 ms², HF component showed sensitivity, specificity, PPV and accuracy of 80%, 100%, 100%, and 86.67% respectively. DAT-SPECT and cardiac MIBG uptake were both normal in ET patients whereas they were markedly decreased in those with PD.ConclusionsIn our study, the LF component of HRV analysis distinguishes ET patients from those with PD on an individual basis, thus representing a valid help in everyday clinical practice for differentiation between these patients in absence of scintigraphic investigations.     

Heart rate and blood pressure variability in patients with myasthenia gravis

This cross-sectional case control study included subjects aged between 18 and 65 years with diagnosis of myasthenia gravis (MG) in Osserman''s Stage I and Stage IIa and those in remission with positive and negative acetylcholine receptor antibody (AChRAb). They were evaluated for heart rate variability (HRV) and other conventional autonomic functions. Patients with co-morbidities that can affect autonomic nervous system were excluded. Repetitive nerve stimulation test (RNST), nerve conduction test, AChRAb assay, and computerized tomography (CT) of chest were done in all the patients. All patients of MG who fulfilled the inclusion criteria had a minimum drug-free period of 6 h which was followed by HRV and other conventional tests. Thirty subjects fulfilling study criteria and an equal number of age and gender-matched healthy subjects were enrolled as controls. Autonomic function tests revealed significant changes in HRV (both time and frequency domain) parameters suggestive of parasympathetic deficiency as well as shifting of sympathovagal balance towards raised sympathetic tone. With regards to conventional autonomic function tests, there was statistically significant decrease in values of heart rate-based tests as well as blood pressure-based test (isometric handgrip test) in study group compared with controls, again indicative of significant parasympathetic deficiency and minimal sympathetic deficiency. We conclude that in MG, cholinergic transmission is affected more diffusely than previously thought.