Depression and heart rate variability in patients with stable coronary heart disease: findings from the Heart and Soul Study

CONTEXT: Depression is associated with low heart rate variability (HRV) in patients following myocardial infarction, suggesting that alterations in the autonomic nervous system may contribute to the adverse cardiac outcomes associated with depression. Whether depression is associated with low HRV in patients with stable coronary heart disease (CHD) is not known. OBJECTIVE: To examine the association between major depression and 24-hour HRV in patients with stable CHD. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study of 873 outpatients with stable CHD recruited from outpatient clinics in the San Francisco Bay Area, California. MAIN OUTCOME MEASURES: Major depression was assessed using the Computerized National Institute of Mental Health Diagnostic Interview Schedule. Heart rate variability was measured by 24-hour ambulatory electrocardiography. RESULTS: A total of 195 participants (22%) had major depression. Overall, we observed no association between depression and HRV as measured by time domain or frequency domain variables. Mean HRV was similar in participants with and without depression (all P values >.10), and participants with depression were no more likely than those without depression to have low HRV (all P values >.10). CONCLUSIONS: We found no evidence of an association between depression and HRV in 873 outpatients with stable CHD. These findings raise questions about the potential role of HRV in the association between depression and cardiovascular disease.     

A frontal-vagal network theory for Major Depressive Disorder: Implications for optimizing neuromodulation techniques

Major Depressive Disorder (MDD) is a psychiatric disorder characterized by high comorbidity with cardiovascular disease. Furthermore, a combination of high heart rate (HR) and low heart rate variability (HRV) has been frequently reported in depressed patients. The present review proposes a frontal-vagal (brain-heart) network that overlaps with functional nodes of the depression network. Moreover, we summarize neuromodulation studies that have targeted key nodes in this depression network, with subsequent impact on heart rate (HR) or heart-rate-variability (HRV), such as the dorsolateral prefrontal cortex (DLPFC), subgenual anterior cingulate cortex (sgACC), and the vagus nerve (VN). Based on the interplay of this frontal-vagal network, we emphasize the importance of including HR and HRV measurements in human depression studies, in particular those that conduct neuromodulation, in order to obtain a better understanding of the pathways that are affected, and we explore the possibilities of using this frontal-vagal interplay as a method for target engagement in neuromodulation treatments. This frontal-vagal network theory opens-up the possibility for individualizing neuromodulation treatments such as rTMS. A recent development called Neuro-Cardiac-Guided TMS (NCG-TMS), was developed based on this theory, and an individual-participant meta-analysis is presented. Four studies provide consistent and replicable support for NCG-TMS as a target engagement method, with consistent HR deceleration during frontal TMS and HR acceleration during motor strip TMS.     

Behavioral inhibition system (BIS), behavioral activation system (BAS) and schizophrenia: relationship with psychopathology and physiology

OBJECTIVE: The Behavioral Inhibition System (BIS) and the Behavioral Activation System (BAS) have been conceptualized as two neural motivational systems that regulate sensitivity to punishment (BIS) and reward (BAS). Imbalance in BIS and BAS levels has been reported to be related to various forms of psychopathology. Since sensitivity to stress has been supposed to be a pathway for the development of psychotic symptoms, the aim of this study is to examine BIS and BAS scores in schizophrenia and their relationship with psychopathology and physiology. METHOD: Forty-two patients with schizophrenia (26 men, 16 women), stable on atypical antipsychotics, and 37 healthy controls (17 men, 20 women) were assessed with the use of the Behavioral Inhibition and Behavioral Activation scales. Since increased average heart rate (HR) and decreased heart rate variability (HRV) have been reported in patients with schizophrenia and have been shown to correlate with inhibited behaviour, these psychophysiological measures were also obtained. The BIS/BAS data and HR/HRV data were both analyzed by a (M)ANOVA. Correlation coefficients were computed for associations between BIS/BAS data, HR/HRV data, and patient variables. RESULTS: On the BIS, patients showed higher sensitivity to threat than control subjects. Higher BIS sensitivity correlated with longer duration of illness, and lower negative symptoms on the PANSS. The BAS scores did not reveal differences between patients and controls. In patients, low BAS sensitivity correlated with low dosage of medication. On the physiological measures patients showed a significantly higher HR and lower HRV compared to controls, which was limited to clozapine treated patients. No correlations were found between HR/HRV scores and BIS/BAS scores or patient variables. CONCLUSIONS: Male as well as female patients with schizophrenia are more sensitive to threat than healthy controls. This may reflect a trait-related characteristic, and is not reflected in state-related psychophysiological measures.     

Attentional and physiological characteristics of patients with dental anxiety

Twenty patients with dental anxiety were investigated while seated in a dental chair in a dental clinic. Heart rate (HR), heart rate variability (HRV), and skin conductance level (SCL) were recorded while the patients were exposed to scenes of dental treatment as well as a Stroop attentional task. Results showed an attentional bias with longer manual reaction times (RT's) to the incongruent compared to the congruent color words as well as the threat compared to the neutral words. Longer RT's to the incongruent and the threat words were found in the low HRV patients compared to the high HRV patients. Furthermore, all patients showed an increase in HR during exposure and the Stroop task compared to baseline. The HRV showed a decrease during the exposure and the Stroop task compared to baseline. HR and HRV did not differ between exposure and the Stroop task. Moreover, HR and HRV did not return to baseline levels during the recovery period. The SCL showed an increase from baseline to exposure, from exposure to the Stroop task and a decrease in the recovery phase. Results showed the importance of vagal cardiac control in attentional, emotional, and physiological processes in patients suffering from dental fear.     

The relationships among heart rate variability,inflammatory markers and depression in coronary heart disease patients

Studies show negative correlations between heart rate variability (HRV) and inflammatory markers. In cardiac patients, depression is related to both. We investigated links between short-term HRV and inflammatory markers in relation to depression in acute coronary syndrome (ACS) patients.We measured C-reactive protein (CRP), interleukin-6 (IL-6), depression symptoms (Beck Depression Inventory, BDI-II), and SDNN, high frequency (HF) and low frequency (LF) power at rest in 682 (553 men) patients approximately two months post-ACS.There were no differences in HRV measures between those with and without elevated depressions symptoms (BDI-II?14). However, all HRV measures were negatively and significantly associated with both inflammatory markers. Relationships were stronger in patients with BDI-II?14. Differences were significant for CRP and not explained by covariates (including age, sex, previous MI, left ventricular ejection fraction, coronary bypass surgery at index admission, diabetes, smoking, body mass index (BMI), fasting cholesterol, fasting glucose, angiotensin-converting-enzyme inhibitors, beta-blockers, statins, and antidepressants). HRV independently accounted for at least 4% of the variance in CRP in the depressed, more than any factor except BMI.Relationships between measures of inflammation and autonomic function are stronger among depressed than non-depressed cardiac patients. Interventions targeting regulation of both autonomic control and inflammation may be of particular importance.     

Major depression, heart rate, and plasma norepinephrine in patients with coronary heart disease.

BACKGROUND: Although it is now well established that psychiatric depression is associated with adverse outcomes in patients with coronary heart disease (CHD), the mechanism underlying this association is unclear. Elevated heart rate (HR) and plasma norepinephrine (NE), possibly reflecting altered autonomic nervous system activity, have been documented in medically well depressed psychiatric patients, and this pattern is associated with increased risk for cardiac events in patients with CHD. The purpose of this study was to determine whether autonomic nervous system activity is altered in depressed CHD patients. METHODS: HR, plasma NE, and blood pressure (BP) were measured in 50 depressed and 39 medically comparable nondepressed CHD patients at rest and during orthostatic challenge. RESULTS: Resting HR (p = .005), and the change from resting HR at 2, 5, and 10 min after standing (p = .02, .004, and .02, respectively), were significantly higher in the depressed than in the nondepressed patients. There were no differences between the groups in NE or in BP at rest, or in standing minus resting change scores at any time during orthostatic challenge (p < .05). CONCLUSIONS: Depression is associated with altered autonomic activity in patients with CHD, as reflected by elevated resting HR and an exaggerated HR response to orthostatic challenge. Previously reported differences in NE levels between depressed and nondepressed patients were not replicated.     

Association Between Smoking and Heart Rate Variability Among Individuals with Depression

Background

Both depression and smoking have been independently associated with lower heart rate variability (HRV), suggesting dysregulation of cardiac autonomic function. However, no studies have systematically explored the effects of smoking on HRV among depressed patients.

Purpose

This study examined differences in HRV based on smoking status among depressed individuals.

Methods

Electrophysiological data were examined among 77 adult outpatients without a history of myocardial infarction, who met criteria for major depressive disorder or dysthymia. Frequency domain [low frequency (LF), high frequency (HF), LF/HF ratio, respiratory sinus arrhythmia (RSA)] parameters of HRV, and heart rate and inter-beat interval (IBI) data were compared between depressed smokers (n?=?34) and depressed nonsmokers (n?=?44).

Results

After controlling for covariates, depressed smokers, compared to depressed nonsmokers, displayed significantly lower LF, HF, and RSA.

Conclusions

Among depressed patients, smoking is associated with significantly lower HRV, indicating dysregulated autonomic modulation of the heart.     

Sexual dimorphism in the human brain: evaluation of tissue volume, tissue composition and surface anatomy using magnetic resonance imaging

Power spectral analysis (PSA) of heart rate variability (HRV) offers reliable assessment of cardiovascular autonomic responses, providing a 'window' onto the interaction of peripheral sympathetic and parasympathetic tone. Alterations in HRV are associated with various physiological and pathophysiological processes, and may contribute to morbidity and mortality. Previous studies of posttraumatic stress disorder (PTSD) found lower resting HRV in patients compared to controls, suggesting increased sympathetic and decreased parasympathetic tone. This article describes the analysis of HRV at rest and after psychological stress in panic disorder (PD) patients, in an enlarged sample of PTSD patients, and in healthy control subjects. Standardized heart rate (HR) analysis was carried out in 14 PTSD patients, 11 PD patients and 25 matched controls. ECG recordings were made while subjects were resting ('rest 1'), while recalling the trauma implicated in PTSD, or the circumstances of a severe panic attack, as appropriate ('recall'), and again while resting ('rest 2'). Controls were asked to recall a stressful life event during recall. While both patient groups had elevated HR and low frequency (LF) components of HRV at baseline (suggesting increased sympathetic activity), PTSD patients, unlike PD patients and controls, failed to respond to the recall stress with increases in HR and LF. HRV analysis demonstrates significant differences in autonomic regulation of PTSD and PD patients compared to each other and to control subjects. HRV analysis may augment biochemical studies of peripheral measures in these disorders.     

Heart rate variability and markers of inflammation and coagulation in depressed patients with coronary heart disease

BACKGROUND: Depression is associated with an increased risk for cardiac morbidity and mortality in patients with coronary heart disease (CHD). Cardiac autonomic nervous system (ANS) dysregulation, proinflammatory processes, and procoagulant processes have been suggested as possible explanations. METHODS: Heart rate variability (HRV), an indicator of cardiac autonomic regulation, and markers of inflammation [C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha)] and coagulation (fibrinogen) were assessed in 44 depressed patients with CHD. RESULTS: Moderate, negative correlations were found between fibrinogen and four measures of HRV. IL-6 also negatively correlated with one measure of HRV (total power) and was marginally related to two others (very low frequency and low frequency power). Neither CRP nor TNF-alpha was significantly related to any measure of HRV. CONCLUSIONS: The finding that fibrinogen and IL-6 are moderately related to HRV suggests a link between these factors in depressed CHD patients. The relationship between ANS function and inflammatory and coagulant processes should be investigated in larger mechanistic studies of depression and cardiac morbidity and mortality.     

Effect of medication and psychotherapy on heart rate variability in panic disorder

Background: Panic disorder (PD) patients have been shown to have reduced heart rate variability (HRV). Low HRV has been associated with elevated risk for cardiovascular disease. Our aim was to investigate the effects of treatment on heart rate (HR) in patients with PD through a hyperventilation challenge. Methods: We studied 54 participants, 43 with Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV) PD and 11 controls. Subjects lay supine with their heads in a plastic canopy chamber, resting for 15 min and then breathing at a rate of 30 breaths per minute for 10 min. HRV was sampled for spectral analysis. Clinical and behavioral measures of anxiety were assessed. Treatment was chosen by patients: either 12 weeks of CBT alone or CBT with sertraline. Results: All patients showed significant decrease on clinical measures from baseline and 31 were treatment responders, 8 dropped out of the study before completion of the 12‐week treatment phase and 4 were deemed nonresponders after 12 weeks of treatment. Although both treatments led to significant clinical improvement, only CBT alone demonstrated a significant reduction in HR and increase in HRV. Conclusions: Our study replicated the finding that increased HR and decreased HRV occur in PD patients. Given the evidence of cardiac risk related to HRV, CBT appears to have additional benefits beyond symptom reduction. The mechanisms of this difference between CBT and sertraline are unclear and require further study. Depression and Anxiety, 2009. © 2008 Wiley‐Liss, Inc.     

Heart rate variability in acute coronary syndrome patients with major depression: influence of sertraline and mood improvement

CONTEXT: Major depressive disorder (MDD) associated with acute coronary syndrome (ACS) increases the risk of mortality. Decreased heart rate variability (HRV), also a predictor of mortality, is reduced in patients with MDD after ACS, and has been suggested to be a mediator of MDD mortality after ACS. Although selective serotonin reuptake inhibitors may reduce mortality post-ACS, little is known about their effects on HRV. OBJECTIVE: To examine the influence of both sertraline and improvement in mood on HRV. METHODS: The Sertraline Antidepressant Heart Attack Randomized Trial assessed HRV from 24-hour Holter electrocardiogram recordings at baseline in 290 patients and from a second recording in 258 of these patients 16 weeks after randomization to sertraline or placebo. Frequency domain measures of HRV included high-frequency power, low-frequency power, very low-frequency power, ultra low-frequency power, and total power. Depression severity was measured by the Hamilton Rating Scale for Depression. Clinical response was measured with the Clinical Global Impressions Improvement scale. RESULTS: At baseline, prior episodes of MDD were associated with lower HRV. Sertraline significantly increased ultra low-frequency power, while improvement in mood was associated with higher low-frequency power independent of treatment. However, the expected recovery in HRV following ACS was not observed in patients with MDD. Higher ultra low-frequency during sertraline treatment and higher low-frequency power in patients whose mood improved resulted primarily from these measures decreasing in their comparison groups. CONCLUSIONS: Heart rate variability recovery is impaired in depressed patients after ACS. Previously reported differences in baseline HRV between patients with and without depression after ACS grew larger in the 16 weeks following a coronary event. Both sertraline treatment and symptomatic recovery from depression were associated with increased HRV compared with placebo-treated and nonrecovered post-ACS control groups, respectively, but this results primarily from decreased HRV in the comparison groups.     

Heart rate and heart rate variability parameters at rest,during activity and passive standing among children with cerebral palsy GMFCS IV–V

Aims: To describe and compare heart rate (HR) and heart rate variability (HRV) at rest, during active movements and passive standing among children with cerebral palsy (CP), with Gross Motor Function Classification System (GMFCS) levels IV and V, and to describe the association between daily physical activity and HRV. Methods: Thirty children with CP were included aged 6–12 years. HR and HRV parameters were recorded during rest, during Gross Motor Functional Measure (GMFM) assessment, during two minutes of repeated performance of the highest activity achieved in the GMFM, and during passive standing. Parents were asked to inform about any habitual physical activities their child participates outside school in the previous 4 months. Results: Children with GMFCS IV increased their HR and reduced HRV values during the GMFM assessment, the repeated task and during passive standing, while no such effect was noted among children with GMFCS V. Children participated in a limited range of activities with a median frequency of three times a week (range 1–6 times), with insignificant differences between GMFCS levels. No significant differences were noted in HR or HRV parameters based on activity level. Conclusions: Only children with GMFCS IV responded to passive and active manipulation of the cardiac autonomic system. This may imply that the HR autonomic regulation system has an opportunity to be influenced by training in this group of children.     

Conjugal loss and syndromal depression in a sample of elders aged 70 years or older.

OBJECTIVE: The goal of this study was to describe the association between conjugal loss and both syndromal depression and depressive symptoms in a prospective cohort study of people aged 70 years or older. METHOD: A measure of syndromal depression, the shortform Composite International Diagnostic Interview (CIDI), and a revised version of the Center for Epidemiologic Studies--Depression Scale (CES-D Scale) were administered to a group of 5,449 elders in a longitudinal cohort study. The authors compared the rates of syndromal depression (CIDI diagnosis) and depressive symptoms (six CES-D Scale symptoms) in married participants and those who lost spouses between the first and second waves of assessment. RESULTS: The rate of syndromal depression in the newly bereaved was nearly nine times as high as the rate for married individuals, and the rate of depressive symptoms was nearly four times as high. The percentage of the bereaved respondents who had scores above threshold on the revised CES-D Scale was higher for those interviewed up to 2 years after loss of a spouse than for married respondents. Age, sex, prior psychiatric history, and the expectedness of the death did not differ between depressed and nondepressed newly bereaved subjects. CONCLUSIONS: Recent bereavement is a significant risk factor for syndromal depression in the elderly. Some widows and widowers experienced high levels of depressive symptoms up to 2 years after the loss of their spouses. Neither demographic variables nor variables concerning the nature of the spouse's death predicted bereavement-related depression.     

Physiologic autonomic arousal heralds motor manifestations of seizures in nocturnal frontal lobe epilepsy: implications for pathophysiology

ObjectiveThis study describes changes in heart rate (HR) and HR variability (HRV) related to clinical onset of seizures in nocturnal frontal lobe epilepsy (NFLE) in order to determine whether signs of autonomic activation precede onset of seizure motor manifestations, which was selected as seizure onset (SO). Further, to clarify the nature (epileptic or physiologic) of the changes in autonomic cardiac control presumed to precede SO, time-dependent variations in HR and HRV related to physiological cortical arousals associated with motor activity (phases of transitory activation, PAT) were also investigated.MethodsHR and HRV spectral power, quantified by means of wavelet transform, were analyzed in relation to the onset of motor manifestations in 45 NFLE seizures and 45 PAT derived from whole night video-polysomnographic recordings of ten patients and of ten control subjects, respectively.ResultsAnalysis of HRV showed a shift of sympathetic/parasympathetic cardiac control toward a sympathetic predominance in the 10 s immediately preceding SO, while changes in HR were evident only one second before SO. This sympathetic activation was not associated with a sleep-wake transition or changes in respiratory activity, both of which occurred concurrently with SO. Similar changes in HR and HRV were observed in the 10 s before the motor and electroencephalographic onset of PAT.ConclusionsOur study demonstrates that a similar autonomic activation precedes the motor manifestations of NFLE seizures and physiological arousal. This autonomic activation could represent part of the arousal response, which could be implicated in the occurrence of both seizure and arousal motor manifestations.     

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.     

Circadian affective, cardiopulmonary, and cortisol variability in depressed and nondepressed individuals at risk for cardiovascular disease

Depression is a risk factor for cardiovascular disease (CVD) perhaps mediated by hypothalamic–pituitary–adrenal (HPA) axis or vagal dysregulation. We investigated circadian mood variation and HPA-axis and autonomic function in older (55 years) depressed and nondepressed volunteers at risk for CVD by assessing diurnal positive and negative affect (PA, NA), cortisol, and cardiopulmonary variables in 46 moderately depressed and 19 nondepressed volunteers with elevated CVD risk. Participants sat quietly for 5-min periods (10:00, 12:00, 14:00, 17:00, 19:00, and 21:00), and then completed an electronic diary assessing PA and NA. Traditional and respiration-controlled heart rate variability (HRV) variables were computed for these periods as an index of vagal activity. Salivary cortisols were collected at waking, waking+30 min, 12:00, 17:00, and 21:00 h. Cortisol peaked in the early morning after waking, and gradually declined over the day, but did not differ between groups. PA was lower and NA was higher in the depressed group throughout the day. HRV did not differ between groups. Negative emotions were inversely related to respiratory sinus arrhythmia in nondepressed participants. We conclude that moderately depressed patients do not show abnormal HPA-axis function. Diurnal PA and NA distinguish depressed from nondepressed individuals at risk for CVD, while measures of vagal regulation, even when controlled for physical activity and respiratory confounds, do not. Diurnal mood variations of older individuals at risk for CVD differ from those reported for other groups and daily fluctuations in NA are not related to cardiac autonomic control in depressed individuals.     

Benefits of exercise training in diabetic rats persist after three weeks of detraining

Regarding all benefits of exercise training, a question remains: how long are these benefits kept? This study evaluated the effect of 3-week detraining after 10 weeks of training in STZ-diabetic rats. Male Wistar rats were assigned into: sedentary controls, trained controls, trained–detrained controls, sedentary diabetic, trained diabetic and trained–detrained diabetic. Arterial pressure (AP) and heart rate (HR) were recorded by a data acquisition system. Baroreflex sensitivity (BRS) was evaluated by HR responses to AP changes induced by infusion of vasoactive drugs. Intrinsic heart rate (IHR), sympathetic tonus (ST) and vagal tonus (VT) were evaluated by pharmacological blockade with atenolol and atropine. Spectral analysis of systolic AP and HR variabilities (HRV) was performed to estimate autonomic modulation to the heart and vessels. Diabetes cardiovascular and autonomic dysfunctions were reversed by exercise training and partially maintained in the 3-week detraining period. In controls, training decreased AP and HR and improved BRS, changes that returned to baseline values after detraining. IHR and VT were improved in trained diabetic rats and remained in detrained diabetic ones. LF component of HRV decreased in trained control group. In diabetics, exercise training improved variance, and absolute LF and HF components of HRV. Only HF was maintained in detrained diabetic group. Moreover, there was an inverse relationship between plasma glucose and the absolute HF component of HRV. These changes probably determined the different survival rate of 80% in diabetic detrained and 51% in diabetic sedentary rats.     

The effect of depression on heart rate variability during pregnancy

Depression during pregnancy has been associated with a number of adverse outcomes, but the underlying physiological mechanisms involved remain unclear. The purpose of this study was to examine the effects of maternal depression during pregnancy on the autonomic modulation of heart rate, in a naturalistic setting. Eighty-one pregnant women were studied between 25 and 31 weeks of gestation and were identified as either Depressed (n = 46), or healthy, Control (n = 35), based on depression scores and lifetime psychiatric history. Subjects wore a 24-h Holter recorder to measure time-domain and frequency-domain of heart rate variability (HRV). Pregnant women in the Depressed Group had significantly reduced time-domain measures: standard deviation of all 24-h NN intervals (SDNN) and the standard deviation of the averages of NN intervals in all 5-min segments of the entire recording (SDANN) (P = 0.013, 0.016, respectively), as well as higher heart rates while asleep (P = 0.028), compared to Controls, after controlling for age, smoking, and antidepressant (AD) medication. The low frequency/high frequency (LF/HF) ratio during the sleeping hours was associated with higher depression scores (R = 0.24; P = 0.041). HRV measures improved in women taking AD medication. The autonomic nervous system may be affected in women experiencing depression during pregnancy, indicating a possible decreased parasympathetic (vagal) influence. Women taking AD medication showed some improvement in HRV measures. These data suggest that psychophysiological changes occur in women experiencing depression during pregnancy.     

Heart rate, tonic cardiac variability and evaluation

Heart rate (HR) and various measures of heart rate variability (HRV) were measured while 29 male and 15 female student volunteers individually rated slide stimuli presented in one-minute intervals. Ratings were factor analyzed and factor scores analyzed as variables. Factor one: “evaluation” accounted for 52.5% of the variances. HR and HRV were not significantly related to the experimental conditions although factor one was related. HR was correlated to measures of HRV [such as the coefficient of variability (CV), coefficient of temporal variability (CVT), a cosine function (FREQ) and to a lesser degree the auto-correlation (RA)]. HR also correlated linearly to evaluation. CVT, CV and RA were also linearly correlated to evaluation. HRV (BURST) was independent of HR, other forms of HRV, and curvilinearly related to evaluation. A cyclic HRV function (FREQ) was found with a mode of 18.7 sec and accounted for 21.4% of the variance of the heart beat data. This cyclic function, not reported previously, should be further investigated.     

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 ms²; 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 ms²; HF was 227.0 ± 284.4 ms²; 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.