Derangement In Autonomic Functions With Elevated Blood Pressure

Background: Prehypertension exhibits approximately 62% of cardiovascular disease and 49% of ischemic heart disease (IHD) global morbidity burden. Heart Rate Variability (HRV) is a fundamental noninvasive technique to assess the autonomic influence on cardiovascular system using time domain and frequency domain methods. We explored the effects of family history of hypertension, prehypertension and hypertension on autonomic functions amongst natives of Uttarakhand region. Methodology: This cross sectional analytical study was designed to explore effects of family history of hypertension, pre-hypertension and hypertension on autonomic functions on 100 subjects divided in four groups using HRV analysis. Results: Autonomic function Analysis of our results showed an increased sympathetic activity among family history of hypertension, pre-hypertension and hypertension as evident by a significant increase in Low frequency normalized unit (LFnu), an increased LF/HF ratio and a significantly reduced High frequency Normalized unit (HFnu) and E/I ratio (p<0.05). Conclusion: Thus, altered cardiac autonomic functions are one of the early manifestations of raised blood pressure and can potentially be used in predicting hypertension at an early stage.

Spectral analysis of heart rate variability in bronchial asthma patients.

The study was carried in the Departments of Physiology and Medicine at S.M.S. Medical College, Jaipur. Thirty patients of bronchial asthma, aged 20-30 years attending outpatient clinics of S.M.S. Hospital and thirty healthy volunteers were recruited in the present study for spectral analysis of Heart Rate Variability (HRV) using impedance peripheral pulse in the right forearm. Two spectral components were recorded namely high frequency (HF) component (0.15–0.4 Hz), an indicator of vagal efferent activity and low frequency (LF) component (0.04–0.15 Hz), replicator of composite sympatho-vagal interplay. These components were analyzed as LF nu (Low Frequency normalized unit), HF nu (High Frequency normalized unit) and LF/HF ratio. Low frequency component in absolute units of the asthmatic patients differed insignificantly (P>0.05) from LF of the subjects, whereas the same calculated as normalized units was found to be significantly low in the patient group (P<0.01), as compared to that of the control group. The High Frequency (in absolute units) index of HRV was significantly high in asthmatics (P<0.01) as compared to the HF (absolute units) of controls. Similar trend was observed in the normalized units of HF (P<0.01). LF/HF ratio was not significantly different in patient and control groups (P>0.05). It was concluded that a significantly raised central vagal outflow and a concomitant significantly low central sympathetic efferent could be appreciated in asymptomatic asthmatic patients as compared to that in the control group. This deranged sympathovagal interplay with parasympathetic dominance could be a plausible pathophysiological mechanism leading to airway obstruction, the hallmark of bronchial asthma.

Heart Rate Variability in Psychiatry / 신경정신의학

The analysis of heart rate variability is a useful tool to investigate the physiologic phenomena related with autonomic functions. At first, it was developed to evaluate the relation between cardiovascular disease and autonomic balance. Nowadays, the application of it's use has been considered in psychiatric practice. And its convenient usage and non-invasiveness gathered more interest of clinicians and investigators. However, no systematic review of the studies on the heart rate variability in psychiatric field is tound. Thus we reviewed the literatures on the usage and it's limitations of the heart rate variability in terms of the spplication in psychiaric practice and research. Interviews with experts on autonomic functions were also included to supplement the review. Studies found that patients with schizophrenia showed reduced heart rate variability while taking clozapine, and severely depressed patients showed more reduced heart rate variability than normal control. Patients with various anxiety disorders including panic disorder and posttraumatic stress disorder showed eleated sympathetic autonomic tone compared with normal control subjects. However these findings remained controversial because of many confounding factors including drug effects and individual and situational factors affecting heart rate variability. With further studies after successful control of confounding variables, the analysis of heart rate variability would be a useful physiologic parameter of asessing psychiatric patients in clinical practice and research.

Autonomic Responses due to Transcutaneous Electrical Nerve Stimulation Apparatus CONVALES / 日本温泉気候物理医学会雑誌

This study was conducted to observe autonomic nervous system reactions in the cardiovascular system caused by the new transcutaneous electrical nerve stimulation apparatus CONVALES^®<br>Autonomic functions were evaluated before and after stimulation of 10 male students between 19 and 42 years of age. The dynamic observation method of autonomic functions proposed by Nishijo et al. was used for evaluating autonomic responses. The activity levels of both the sympathetic and parasympathetic systems were found to increased after stimulation. Neither significant changes in blood pressure nor adverse effects of stimulation were observed.<br>These results suggest that the apparatus used in this study causes autonomic responses similar to those caused by acupuncture with shallow needling during exhalation phase while sitting, or by laser acupuncture. This study also suggested that this therapeutic method is safe for short periods.