28The alteration of multi-channel Electrogastrography and autonomic nervous system function in patients with gastroesophageal reflux disease with test meal

The aims of this study were to utilize multi‐channel electrogastrography (MEGG) and power spectra analysis of Heart Rate Variability (HRV) to investigate the effects of test meal on MEGG and autonomic nervous system (ANS) function in patients with gastroesophageal reflux disease (GERD). Methods: Sixteen patients with the diagnosis of GERD were enrolled in this study (11 M, 5 F, mean age: 47 yrs) and 16 healthy subjects (HS) matched for age and gender were recruited as control (11 M, 5 F, mean age: 47 yrs). MEGG was recorded simultaneously with the electrocardiogram (ECG) recording for 30 min in the fasting state and 60 min after a standard test meal (450 Kcal). MEGG parameters included dominant frequency (DF), dominant power (DP), the normal percentage of 2–4 cpm gastric slow waves (%N) and the percentage of slow wave coupling (%SWC). ANS parameters included sympathovagal balance LF/HF Ratio, mainly sympathetic activity LF and vagal activity HF. Results: (1) Compared with fasting state, test meal significantly increased the DF but decreased the %N and %SWC in both GERD patients and HS in the 1st 30 min and 2nd 30 min fed state (P < 0.05). DP was not significantly altered by test meal in both groups in fed state. However, there is no significant difference between 1st 30 min and 2nd 30 min fed state for DF, %N and %SWC. 2) Compared with fasting state, test meal significantly increased the LF/HF ratio and LF but decreased the HF in both groups in the 1st 30 min after meal (P < 0.05), however, the increase of LF/HF ratio and LF but decrease of HF were still present in HS whereas absent in patients with GERD in the 2nd 30 min fed state. There is no significant difference between 1st 30 min and 2nd 30 min fed state for those ANS parameters. (3) There was no significant difference between GERD patients and HS in any of those MEGG and ANS parameters neither in fasting state nor in fed state. (4) There was no significant correlation between MEGG parameters and ANS parameters neither in fasting state nor in fed state in both groups. Conclusions: Both patients with GERD and HS may have similar response to test meal in MEGG test. GERD patients could not maintain the response to test meal longer in ANS test suggests that GERD patients may have impaired ANS regulation to test meal.     

Heart rate variability in children with refractory generalized epilepsy.

OBJECTIVE: Repetitive seizures can alter the regulation of cardiac activity by the autonomic nervous system (ANS), and ANS dysregulation is thought to be associated with higher morbidity and mortality in epileptic patients, especially from sudden unexpected death. Few studies of interictal dysregulation of cardiac activity in children with epilepsy have been performed. In this study we characterize heart rate variability (HRV) in children with refractory generalized epilepsy. METHODS: Fifteen male and 15 female children, average age = 10.9+/-0.6 years, all with refractory generalized epilepsy were enrolled into the study group. A control group consisted of 15 males and 15 females with average age = 10.6+/-0.6 years. A lead I ECG was recorded for 5 min in the interictal period during daylight hours from each subject while awake. Frequency-domain analysis of HRV was performed using a non-parametric method of fast Fourier transformation. Changes of HRV were categorized into high frequency power (HF; 0.15-0.45 Hz), which represented vagal regulation, and low frequency power (LF; 0.04-0.15 Hz). LF/(HF+LF) expressed in normalized units (LF%) was considered to mirror sympathetic regulation. RESULTS: There were significant reductions in RR, LF, and HF in the study group when compared to controls. There was no significant difference in LF% between the two groups. CONCLUSIONS: We postulate that the lower HRV in our patients results from parasympathetic or vagal reduction. This suggests that decreased HRV in epileptic children occurs by a different mechanism than in adults with epilepsy.     

31Effects of test meal on multi-channel Electrogastrography and autonomic nervous system function in different subtypes of patients with functional dyspepsia

Previous studies have shown that patients with functional dyspepsia (FD) had significantly lower percentage of slow wave coupling (%SWC) in fasting state. The aim of this study was to utilize MEGG and ANS test to investigate the difference of MEGG parameters and ANS parameters between different subtypes of FD patients and healthy subjects (HS). Methods: Sixty‐two patients with the diagnosis of FD were enrolled in this study (16 M, 46 F, mean age: 43 years) and divided into dysmotility‐like FD group (15 M, 35 F, mean age: 42 years) and ulcer‐like FD group (1 M, 11 F, mean age: 46 years) based on Rome II criteria. 50 HS were recruited as control (25 M, 25 F, mean age: 44 years). MEGG were recorded simultaneously with the electrocardiogram (ECG) recording for 30 min in the fasting state and 60 min after a standard 450 Kcal test meal. MEGG parameters included dominant frequency (DF), normal percentage of 2–4 cpm gastric slow waves (%N) and %SWC. ANS parameters included sympathovagal balance LF/HF Ratio, mainly sympathetic activity LF and vagal activity HF. Results: (1) Compared with HS, %SWC was significantly lower in ulcer‐like FD group in fasting state (P < 0.05) but not in fed state. No significant difference of %SWC was shown between dysmotility‐like FD group and HS either in fasting state or in fed state. There was no significant difference between the two FD groups and HS in DF and %N neither in fasting state nor in fed state. (2) Compared with HS, LF/HF ratio and LF were significantly lower and HF was significantly higher in fasting state in dysmotility‐like FD group (P < 0.05), this difference was abolished by test meal in the 1st 30 min fed state and the lower LF and higher HF were present in the 2nd 30 min fed state again in dysmotility‐like FD group. There was no significant difference between ulcer‐like FD group and HS in any of those ANS parameters either in fasting state or in fed state. Conclusions: Gastric slow wave coupling was abnormal in patients with ulcer‐like FD. Patients with dysmotility‐like FD had abnormal ANS function in fasting state and test meal could only correct the abnormal ANS for short time, which suggest that different subtypes of FD may have different patterns in ANS test.     

Computerized dynamic pupillometry as a screening tool for evaluation of autonomic activity

ObjectivesDynamic pupillometry is a simple screening tool for quantifying pupillary light reflex (PLR), to indicate autonomic nervous system (ANS) activity. Heart rate variability (HRV) is the gold standard method for assessing ANS effects on the heart. The present study aimed to compare ANS activity as measured using dynamic pupillometry (DP) with short term HRV in healthy volunteers.MethodsThe study includes 200 participants aged between 20–60 years. PLR was measured using infrared videography and categorized into different quantitative parameters that reflect ANS activity. Simultaneously, Lead II ECG was recorded for 5 min to evaluate the short term HRV of time and frequency domain parameters. The data obtained from the two methods were compared with each other to provide the relationship between PLR and HRV.ResultsStudy participants’ mean age was 36.95 ± 9.45 years. The different pupillary indices of PLR and all the HRV parameters were within the range of normative data. Several PLR indicators of the parasympathetic function include mean constriction velocity (MCV; r = 0.60, P < 0.001), absolute constriction amplitude (ACA; r = 0.57, P < 0.001) baseline pupil diameter (BPD; r = 0.44, p < 0.001), and minimum pupil diameter (MPD; r = −0.35, p < 0.001) were significantly correlated with high-frequency power (HF in normalized units) of HRV signal.ConclusionPLR variables showed a significant relationship to HRV indices. Dynamic pupillometry can be a complementary tool to HRV for evaluating ANS activity.     

Assessment of autonomic nervous system function in patients with Behçet' s disease by spectral analysis of heart rate variability

The purpose of this study was to evaluate the autonomic nervous system (ANS) function in patients with Behcet's disease by using power spectral analysis of heart rate variability (HRV). The study population consisted of 71 patients with Behcet's disease, and 26 normal volunteers. HRV was measured by power spectral analysis in supine and standing position. In supine position, Behcet's patients had increased low frequency component in absolute (LF) and normalized units (LF nU) but had lower values of high frequency component in absolute (HF) and normalized units (HF nU) than the controls (P < 0.05). In standing position, higher values were obtained in LF and LF nU but lower values of HF and HF nU in Behcet's patients than controls (P < 0.05). LF/HF was significantly higher in patients both in supine (2.5 +/- 1.0 vs. 1.2 +/- 0.8, P = 0.001) and standing (21.9 +/- 7 vs. 1.8 +/- 0.3, P < 0.001) positions. Our data suggest that patients with Behcet's disease may have asymptomatic ANS dysfunction, which is in the form of increased sympathetic and decreased parasympathetic modulation, and power spectral analysis of HRV is beneficial in assessing the ANS function.     

Autonomic nervous system response to a solid meal and water loading in healthy children: its relation to gastric myoelectrical activity

The aim of this study was to investigate the correlation of gastric myoelectrical and autonomic activities in healthy children. Simultaneous recordings of electrogastrography (EGG) and electrocardiogram (ECG) were performed in healthy children before and after a solid meal and water loading respectively. The autonomic activity was assessed by spectral analysis of the heart rate variability (HRV). The solid meal resulted in an increase in EGG-dominant frequency (2.92 cpm vs 3.16 cpm, P < 0.05), dominant power (46.9 dB vs 53.7 dB, P < 0.05) and percentage normal slow waves (81.9%vs 89.0%, P < 0.05), while only dominant power increased following water loading. Power in the low-frequency band of HRV (LF) was significantly increased and power in the high-frequency band of HRV (HF) significantly decreased following the solid meal. Postprandial LF was positively and HF negatively correlated with the postprandial increase in EGG-dominant power. Water loading was not associated with any significant changes in HRV parameters. These results suggest that both vagal and sympathetic pathways are involved in modulation of gastric myoelectrical activity.     

Moderate physical exercise increases cardiac autonomic nervous system activity in children with low heart rate variability

Object Our objective was to investigate the effect of a long-term moderate exercise program on cardiac autonomic nervous system (ANS) activity in healthy children.Methods Three hundred and five children aged 6–11 years participated in a 12-month school-based exercise training program (130–140 bpm, 20 min/day, 5 days/week). Cardiac ANS activities were measured using heart rate variability (HRV) power spectral analysis in resting conditions. Following the first measurement, 100 children from the lowest total power (TP) HRV were chosen as experimental samples and the same number of age-, height-, and weight-matched controls (CG) was randomly selected from the remaining children.Results In the low group (LG), all the frequency components of the HRV were significantly increased after the training period, whereas only low-frequency power was augmented in the control group (CG).Conclusion Our data suggest that the 12-month moderate exercise training has a positive effect on cardiac ANS activity in the children who initially had low HRV.A commentary on this paper is available at     

Relationship between ischemic stroke location and autonomic cardiac function

Autonomic cardiac dysfunction is a common complication after acute ischemic stroke (IS). We recruited 75 patients with acute IS with measurements of autonomic cardiac function, including heart rate variability (HRV) and associated parameters, and compared them with 81controls. Of the 75 patients, 28 had right hemispheric infarctions (RH), 29 had left hemispheric infarctions (LH), and 18 had brainstem infarctions (BS). A comparison of HRV in all patients with stroke and in control subjects showed significant differences between IS subgroups and controls in low frequency (LF), high frequency (HF), normalized LF, normalized HF, and LF/HF ranges. A post-hoc comparison identified significant differences between patients with IS with BS infarctions and the control group in LF, HF, and LF/HF ranges. BS infarction may cause a much greater increase in sympathetic modulation and reduced vagal activity compared to RH or LH infarction. Our findings provide evidence that acute IS causes significant damage to the cardiovascular autonomic system, manifesting as abnormalities of HRV. BS stroke might correlate with a significant reduction in parasympathetic and an increase in sympathetic influence on HRV.     

Changes in heart rate dynamics of patients with schizophrenia treated with risperidone

Neurocardiac dysregulation has been reported in schizophrenia. Indices of heart rate variability (HRV) are useful in assessing the status of cardiac autonomic regulation. We explored within-subject changes in HRV indices in acutely ill patients with schizophrenia treated with risperidone. Sixteen medication-naïve or medication-free patients with DSM-IV schizophrenia completed electrocardiogram (ECG) assessments at baseline and after six weeks of treatment with risperidone. Indices of HRV were extracted from 5-min resting ECG recordings and compared to those obtained from control subjects matched for age and gender. Psychiatric and drug-induced extrapyramidal symptoms were assessed by the Positive and Negative Syndrome Scale (PANSS) and the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). In comparison with matched controls, patients with acute schizophrenia showed lower values of time-domain measures, lower high-frequency power (HF) and a higher ratio of low to high frequency (LF/HF). In the within-subject analyses, a significant decrease in LF/HF was associated with risperidone treatment. In addition, LF/HF, which initially co-clustered with clinical variables, congregated with other HRV measures after the six-week risperidone treatment. These results indicate that, in the therapeutic process, risperidone treatment may exert a beneficial influence on the sympathovagal imbalance in acute schizophrenia.     

Heart rate variability response to mental arithmetic stress in patients with schizophrenia: autonomic response to stress in schizophrenia

BACKGROUND: The vulnerability-stress hypothesis is an established model of schizophrenia symptom formation. We sought to characterise the pattern of the cardiac autonomic response to mental arithmetic stress in patients with stable schizophrenia. METHODS: We performed heart rate variability (HRV) analysis on recordings obtained before, during, and after a standard test of autonomic function involving mental stress in 25 patients with DSM-IV schizophrenia (S) and 25 healthy individuals (C). RESULTS: Patients with schizophrenia had a normal response to the mental arithmetic stress test. Relative contributions of low-frequency (LF) HRV and high-frequency (HF) HRV influences on heart rate in patients were similar to controls both at rest (LF 64+/-19% (S) vs. 56+/-16% (C); HF 36+/-19% (S) vs. 44+/-16% (C), t=1.52, p=0.136) and during mental stress, with increased LF (S: 76+/-12%, C: 74+/-11%) and decreased HF (S: 24+/-12%, C: 26+/-11%) in the latter study condition. Whilst healthy persons recovered the resting pattern of HRV immediately after stress termination (LF 60+/-15%, HF 40+/-15%, F=18.5, p<0.001), in patients HRV remained unchanged throughout the observed recovery period, with larger LF (71+/-17%) and lower HF (29+/-17%) compared with baseline (F=7.3, p=0.013). CONCLUSIONS: Patients with schizophrenia exhibit a normal response to the mental arithmetic stress test as a standard test of autonomic function but in contrast with healthy individuals, they maintain stress-related changes of cardiac autonomic function beyond stimulus cessation.     

Comparison of heart rate variability and stroke volume variability

In order to compare the heart rate variability (HRV) and stroke volume variability (SVV), supine electrocardiographic (ECG) and the time series data of left ventricular (LV) volume recordings were taken in 12 healthy adult male volunteers. The low frequency (LF) and high frequency (HF) peaks of HRV and SVV were evaluated quantitatively by power spectral analysis. The fractal dimension (FD) of the time series data was analyzed by the box-counting method. A LF peak around 0.1 Hz and a HF peak around 0.3 Hz were as clearly observed in the SVV spectrum as in the HRV spectrum. The LF/HF ratio in SVV was significantly lower than that in HRV, while the FD was significantly higher in SVV than in HRV. No significant correlation of HF, LF or FD was observed between HRV and SVV. Our results indicate that SVV provides different information about the activity of the autonomic nervous system than HRV.     

Autonomic function in the early stage of panic disorder: power spectral analysis of heart rate variability

Previous studies of autonomic nervous system (ANS) function in panic disorder (PD) patients have yielded conflicting results. We speculate that these differences might result from the variety of clinical stages of PD. In order to investigate this, we compared ANS activity in untreated patients in the early stage of PD with control subjects using power spectral analysis of electrocardiogram R-R intervals (PSR-R) in supine rest and during head-up tilt, which was performed according to the maximum entropy method (MEM). It recognizes two main components: high-frequency power (HF), which mainly reflects cardiac parasympathetic activity, and low-frequency power (LF), which reflects both cardiac sympathetic and parasympathetic activity. The patients with PD had significantly higher values for all components of PSR-R only in tilt position total power (TP), LF, and HF than did the control subjects (P<0.01, <0.01, <0.02, respectively). However, the LF/HF ratio which indicated sympathovagal balance did not differ significantly between the two groups in tilt position. Our findings suggest that patients with PD in the early stage of illness have co-activation of sympathetic and parasympathetic nervous systems, which might act to maintain a balance between the two autonomic systems.     

Abnormal heart rate variability in a subject with second degree atrioventricular blocks during sleep.

OBJECTIVE: We compare the profiles of heart rate variability (HRV) during sleep stages in 9 healthy controls and one subject with second degree atrioventricular blocks (AVB), investigating the role of sympathovagal balance in such pathology. METHOD: Sleep and cardiac records were taken for one night in 9 male subjects from 21:00 to 07:00 h and for two nights in a male subject with AVB. Time and frequency domain indexes of HRV were calculated over 5 min-periods. RESULTS: In one subject without any daytime heart disease, 253 and 318 AVB of type 2 (Mobitz 2) were observed during the two experimental nights, predominantly during rapid eye movement (REM) sleep and the surrounding sleep stage 2 in the second half of the night. In the 9 control subjects, absolute HRV indexes and low frequency (LF)/(LF+high frequency, HF) (where LF and HF are low frequency and high frequency power) were low during slow wave sleep, and significantly increased during REM sleep and the preceding sleep stage 2. In the subject with AVB, these HRV indexes were abnormally low during all sleep stages, with a predominant increase in parasympathetic activity as inferred from low LF/(LF+HF). During wake, however, LF/(LF+HF) normally increased, and the tachycardia observed with the arousal that terminates SWS was preserved in the subject with AVB. CONCLUSION: These results suggest that in the subject with second degree atrioventricular blocks, sleep processes, particularly during REM sleep, create a specific neurological background that prevents an increase in sympathetic tone and triggers cardiac pauses.     

Heart rate variability for assessing comatose patients with different Glasgow Coma Scale scores

ObjectiveTo assess the autonomic nervous system (ANS) in coma by heart rate variability (HRV).MethodsSixteen comatose patients and 22 normal subjects with comparable ages and genders were studied. Patients were classified in two subgroups according to the Glasgow Coma Scale (GCS). Time, frequency, and informational HRV domain indices were calculated.ResultsA notable reduction of HRV was found in patients. Regarding the time domain indices, the triangular index, and the Delta_RRs, were significantly reduced in the subgroup with GCS = 3. Absolute power for the whole frequency spectrum decreased whenever GCS scores were lower. A significant decrement was found for absolute power of the VLF and LF bands in the subgroup of GCS = 3, and although it was lower for the HF band in these patients, those changes were not statistically significantly different. The LF/HF ratio and the Shannon´s entropy indices were significantly reduced in the subgroup with GCS = 3. Our results are discussed regarding the progressive dysfunction the ANS networks when coma deepens.ConclusionsThe HRV procedure is a powerful tool to assess the ANS in comatose patients.SignificanceHRV is a minimally invasive, low-cost methodology, suitable for assessing the ANS in coma.     

Effects of antiepileptic drug therapy on heart rate variability in children with epilepsy

Impaired cardiac autonomic function may contribute to the risk of sudden unexpected death in epilepsy. Heart rate variability (HRV) is a useful tool for the detection of sympathetic-parasympathetic balance of autonomic nervous system. In the present study, epilepsy patients who had never received antiepileptic medication and those whose seizures have been successfully controlled with antiepileptic drugs were compared with each other and a control group in order to investigate the effects of epilepsy and various antiepileptic drugs on HRV. HRV were tested via 5 min ECG monitoring in 92 patients and 83 controls. Time domain parameters including SDNN, RMSSD and the frequency domain parameters including HF (reflects parasympathetic activity) and LF (reflects sympathetic activity) were assessed. In this group, 78 patients were using antiepileptic drugs including valproic acid (n=33), oxcarbazepine (n=19), phenobarbital (n=11), combined regimens (n=10) and other drugs (n=5), while 14 patients had never received antiepileptic medication. For both of the epilepsy patients groups with or without treatment, time domain parameters were found to be significantly suppressed. In addition, parasympathetic activity was found to be decreased (HF was decreased, LF/HF ratio was increased) in epilepsy patients without antiepileptic drug therapy. Our results indicate that seizure control with antiepileptic drugs may help to improve the cardiac autonomic function impairment in epilepsy patients.     

Effects of light and sleep stages on heart rate variability in humans.

Effects of light intensity and sleep stages on heart rate variability (HRV) were investigated in young healthy subjects. The low-frequency (LF)/high-frequency (HF) ratio was significantly increased by exposing either to bright lights of 10 000 lx or to extreme darkness (< 0.01 lx), while HF and LF components of HRV were not changed, when compared with those under dim light (100 lx). However, LF was significantly increased at REM sleep, when compared with that at the pre-sleep wake. In contrast, HF was increased at all stages of sleep, and the LF/HF ratio was decreased at slow wave sleep during the baseline night.     

Comparison of heart rate variability parameters during complex partial seizures and psychogenic nonepileptic seizures

Purpose: Psychogenic nonepileptic seizures (PNES) superficially resemble epileptic seizures. Little is known about ictal autonomic nervous system (ANS) activity changes in epilepsy and PNES. This study compares ictal heart rate variability (HRV) parameters as a reflection of ANS tone in epileptic seizures and PNES, and explores differences between interictal and ictal ANS tone in both patient groups. Methods: Ictal HRV parameters were extracted from single‐lead electrocardiography (ECG) data collected during video–electroencephalography (EEG) recordings of 26 patients with medically refractory temporal lobe epilepsy and 24 age‐ and sex‐matched patients with PNES. One seizure per patient in a resting, wake, supine state was analyzed. Interictal ECG data were available for comparison from 14 patients in both groups. HRV parameters in time and frequency domains were analyzed (low frequency [LF], high frequency [HF], standard deviation of all consecutive normal R wave intervals [SDNN], square root of the mean of the sum of the squares of differences between adjacent normal R wave intervals [RMSSD]). CVI (cardiovagal index), CSI (cardiosympathetic index), and ApEn (approximate entropy) were calculated from Lorenz plots. Key Findings: There were significant differences between ictal HRV measures during epileptic and nonepileptic seizures in the time and frequency domains. CSI (p < 0.001) was higher in epileptic seizures. Time interval between two consecutive R waves in the ECG (RR interval) (p = 0.002), LF (p = 0.02), HF (p = 0.003), and RMSSD (p = 0.003) were significantly lower during epileptic seizures. Binary logistic regression yielded a significant model based on the differences in CSI classifying 88% of patients with epilepsy and 73% of patients with PNES correctly. The comparison between resting and ictal states in both seizure disorders revealed significant differences in RR interval (epilepsy p < 0.001, PNES p = 0.01), CSI (epilepsy p < 0.001, PNES p = 0.02), HF (epilepsy p = 0.002, PNES p = 0.03), and RMSSD (epilepsy p = 0.004, PNES p = 0.04). In patients with epilepsy there were also significant differences in ictal versus interictal mean values of ApEn (p = 0.03) and LF (p = 0.04). Although CSI was significantly higher, the other parameters were lower during the seizures. Stepwise binary regression in the 14 patients with epilepsy produced a significant model differentiating resting state from seizures in 100% of cases. The same statistical approach did not yield a significant model in the PNES group. Significance: Our results show greater ANS activation in epileptic seizures than in PNES. The biggest ictal HRV changes associated with epileptic seizures (CSI, HF, and RMSSD) reflect high sympathetic system activation and reduced vagal tone. The reduced ApEn also reflects a high sympathetic tone. The observed ictal alterations of HRV patterns may be a more specific marker of epileptic seizures than heart rate changes alone. These altered HRV patterns could be used to detect seizures and also to differentiate epileptic seizures from PNES. Larger studies are justified with intergroup and intragroup comparisons between ictal and resting states.     

Autonomic dysfunction responses to head-up tilt in anorexia nervosa

Purpose

Autonomic dysfunction of the cardiovascular system in anorexia nervosa (AN) was reported not only in the rest position, but also in the standing position in some previous studies, which might contribute to cardiac complications such as lethal arrhythmia. However, there has not been sufficient literature in this issue. Therefore, we performed a head-up tilt test, and compared the changes after tilting in indices of autonomic function between AN patients and healthy subjects by heart rate variability (HRV) and blood pressure variability (BPV).

Methods

The subjects were 21 females with AN and 30 age-matched healthy women. A head-up tilt test was performed following the protocol recommended by the American Heart Association. Blood pressure and heart rate data were collected for 10 min before and after tilting. In the frequency analysis, the powers of low-frequency (LF) and high-frequency (HF) components were calculated by a fast Fourier transformation.

Results

Regarding interactions between groups and head-up tilting, the head-up tilting-induced reduction of the HF component of HRV was significantly greater in the AN group. In addition, increases in the LF/HF of HRV and the LF component of BPV after head-up tilting were significantly smaller in the AN group.

Conclusions

Regardless of the posture, changes in HF and LF/HF of HRV and LF of BPV in AN patients suggested the presence of autonomic insufficiency.     

Standardized tests of heart rate variability for autonomic function tests in healthy Koreans

Heart rate variability (HRV) is a noninvasive measure of autonomic input to heart rate that has been successfully used to estimate modulation of autonomic tone. The authors investigated to determine the normal ranges as a standardized tests of heart rate variability (HRV) for autonomic function tests in a large sample of healthy Koreans. The study also evaluated the effects of age, sex, and heart rate (HR) on the results of HRV and the values of HRV in hypertension, diabetes, and obesity group. Six hundred and thirty-seven healthy subjects who visited the health improvement center for medical examination were evaluated. A standardized 5-min resting study, including spectral analysis of HR, was used to all participants after an overnight fast. HRV (SA-2000E, Medicore, Korea) was spectrally determined by three components: total-frequency (TF) component (0.01 to 0.5 Hz), low-frequency (LF) component (0.04 to 0.15 Hz), and high-frequency (HF) component (0.15 to 0.5 Hz). Also two component ratio (LF/HF) was calculated. Routine laboratory and physical examinations were used to eliminate cardiovascular diseases and neurological disorders. The determinants of short-period HRV in a random sample of 366 men and 271 women from healthy subjects were assessed. The mean age of these subjects was 45.1 +/- 10.7 years. The mean value of total power was 1106.9 +/- 1109.1 ms(2); SDNN was 35.9 +/- 15.5 ms; rMSSD was 27.3 +/- 15.6 ms for time domain analysis. The mean value of LF was 287.5 +/- 384.1 ms(2); HF was 227.0 +/- 284.4 ms(2); LF/HF was 2.2 +/- 3.4 for frequency domain analysis. Additionally, men showed that their TP, LF, and LF/HF values were significantly higher than women whereas SDNN, rMSSD, HF showed no significant differences between sexes. With increasing age, there was no significant decrease in HR. TP, SDNN, LF, and HF were significantly decreased when getting older. On the contrary, LF/HF had no significant difference related to age. The study confirmed that SDNN and rMSSD were significantly lower in hypertension and diabetes group. In conclusion, middle-aged men had more pronounced sympathetic influence than women in cardiac regulation, and HRV declined linearly with age. In addition, HRV reflecting the function of autonomic nervous system was decreased in hypertension and diabetes group.     

Does acupuncture influence the cardiac autonomic nervous system in patients with minor depression or anxiety disorders?

We undertook this study to evaluate the effects of needle acupuncture on cardiac autonomic nervous system (ANS) function in patients with minor depression or anxiety disorder. Patients (n = 36) were randomly distributed into a verum acupuncture (VA) group (needles were applied at classical acupuncture points, e. g. He7, Pe6, Du20, Bl62, Ex6) or a placebo (PL) group (needles were applied only epidermal at non-acupuncture points). Both groups underwent standardized measurements of the 5-minute resting heart rate variability (HRV), which were performed before the first and after the 9th acupuncture session of an acupuncture series, and also three times (before the start and 5, respectively, 15 minutes after needle application) during the third acupuncture session. Demographic data between the VA and PL group did not differ. Before the start of acupuncture there were also no significant differences in HRV data between these groups. Compared to PL the VA group showed a significant decrease of the mean resting heart rate both, 5 and 15 minutes after needle application, combined with a trend towards an increase of the high frequency (HF; 0.15 - 0.4 Hz) and a decrease of the low frequency (LF; 0.04 - 0.15 Hz) spectral power. The latter effects resulted in an overall significant decrease of the mean LF/HF ratio in VA compared to PL treated patients. This pattern of findings suggests that in patients with minor depression or anxiety only verum acupuncture 1.) leads to a relative increase of cardiovagal modulation of heart rate and 2.) facilitates the physiological regulatory ANS function in response to alterations of external or internal environment. Clinical implications of these findings are discussed.