Cognitive function is associated with impaired heart rate variability in ageing adults: the Irish longitudinal study on ageing wave one results

Objective

To examine the independent association between heart rate variability (HRV) and cognitive performance, in a nationally representative population study of older adults.

Methods

Cross-sectional analysis of wave 1 data from the Irish longitudinal study on ageing (TILDA) was performed. A subset of 4,763 participants who underwent ECG recording during resting and paced breathing periods were used for the analysis. HRV indices were divided into quintiles for comparison of values and cognitive performance was defined using the Montreal cognitive assessment (MOCA) score. Multivariate linear regression was used to model the association between cognition and different quintiles of each HRV index, after adjustment for covariates.

Results

The mean age was 61.7 ± 8.3 years and 2,618 (55 %) were female. Lower quintiles of SDNN (P = 0.01-paced), LF (P = 0.001-paced), and LF:HF ratio (P = 0.049-paced) were significantly associated with lower MOCA scores (during both recording periods), independent of confounders. Sub-domains of MOCA responsible for the relationship were predominantly memory recall and language.

Interpretation

Reduced HRV is significantly associated with lower cognitive performance at a population level in people aged 50 and older. This further strengthens the relationship between autonomic dysfunction and cognitive disorders.     

The relationship between resting heart rate variability and heart rate recovery

Objective  

There is limited research available regarding a possible relationship between resting heart rate variability (HRV) and post-exercise heart rate recovery (HRR). The aim of this study was to examine the relationship between resting HRV and HRR after maximal exercise.     

Post-exercise heart-rate recovery correlates to resting heart-rate variability in healthy men

Justificative

The relationship between post-exercise heart-rate recovery (HRR) and resting cardiac autonomic modulation is an incompletely explored issue.

Objective

To correlate HRR with resting supine and orthostatic autonomic status.

Method

HRR at the 1st, 3th, and 5th min following maximal treadmill exercise were correlated with 5-min time-domain (CV, pNN50 and rMSSD) and frequency-domain (TP, LF, HF, LFn, HFn, and LF/HF ratio) indices of heart-rate variability (HRV) in both supine and standing positions in 31 healthy physically active non-athletes men. Statistical analysis employed non-parametric tests with two-tailed p value set at 5 %.

Results

Absolute HRR and Δ %HRR at each post-exercise time did not correlated with HRV in supine position, as well as at 1st min in standing position. At the 3rd min and 5th min, these measures negatively correlated with pNN50, rMSSD, TP, and HF indices, and only in the 5th min, they showed negative correlation with HFn and positive correlation with LF, LFn, and LF/HF ratio in the standing position. Coefficient of HRR (CHRR) at the 1st min negatively correlated with pNN50 and rMSSD and at 3rd and 5th min showed positive correlation with LFn and LF/HF ratio in supine position. With HRV indices in standing position CHRR from the 1st to 5th min showed the same respective negative and positive correlations as the other measures.

Conclusion

HRR from the 1st to 5th min post-exercise negatively correlated with parasympathetic modulation in resting orthostatic, but showed no correlation in supine position. At the 3rd and 5th min, a positive correlation with combined sympathetic-parasympathetic modulation in both positions was observed.

     

Linear and nonlinear parameters of heart rate variability in ischemic stroke patients

Introduction

Cardiovascular system presents cortical modulation. Post-stroke outcome can be highly influenced by autonomic nervous system disruption. Heart rate variability (HRV) analysis is a simple non-invasive method to assess sympatho-vagal balance.

A meta-analysis of HIV and heart rate variability in the era of antiretroviral therapy

Background

Heart rate variability (HRV) has been used to assess autonomic dysfunction since the beginning of the HIV epidemic. Although autonomic failure was commonly detected in HIV and AIDS patients prior to the advent of antiretroviral therapy (ART), the effect of HIV on HRV in the current era of widespread ART availability is more ambiguous.

Methods

A systematic search and review was conducted on cross-sectional observational and case–control studies published in the era of ART (1996–2015) that compared HRV between HIV + individuals treated with ART and HIV ? controls. Eight out of the 20 studies identified, enrolling a total of 292 HIV + adults (mean age 38.7 years) and 201 HIV seronegative controls (mean age 35.1 years), were included in a meta-analysis based on stringent methodological criteria.

Results

At rest, individuals with HIV showed lower HRV in the time (g) = ?0.72, 95 % CI (?1.03 to ?0.42) and low-frequency (LF) domain (g) = ?0.51, (?0.81 to ?0.21); markers of lower parasympathetic tone in the time (g) = ?0.55, (?0.85 to ?0.25) and high-frequency (HF) domain (g) = ?0.42, (?0.71 to ?0.12); and higher LF:HF ratio (g) = 0.46, (0.12–0.86) in the frequency domain, suggestive of parasympathetic withdrawal.

Conclusion

This meta-analysis confirmed, within a relatively young cohort of HIV + adults on ART, a general reduction in autonomic function with a shift toward sympathetic dominance. This shift may predispose HIV patients to early and elevated risk of arrhythmias, cardiac events, and accelerated HIV disease progression.

     

Cardiac autonomic modulation and blood pressure responses to isometric handgrip and submaximal cycling exercise in individuals with down syndrome

Purpose

Individuals with Down syndrome (DS) exhibit autonomic dysfunction, manifested as attenuated heart rate (HR) and blood pressure (BP) responses to sympathoexcitation. Whether a subgroup of individuals with DS with a normal HR response would have normal autonomic responses to sympathoexcitation remains unclear.

Methods

We compared autonomic modulation using HR variability (HRV) and BP responses in individuals with and without DS (controls) matched for the HR change to isometric handgrip (HG) (10 DS, 8 controls) and submaximal cycling exercise (CE) (9 DS, 9 controls). HG was performed for 2 min at 30 % of maximal voluntary contraction. CE included two 6-min stages at 0 W and at 50 % of body weight. Beat-to-beat HR and BP were recorded. HRV variables were natural log transformation (Ln) of low frequency (LF), high frequency (HF), LF/HF ratio, total power (TP), and the root mean square of successive differences (RMSSD).

Results

In the HG study, although individuals with DS exhibited an overall lower systolic BP, LF/HF ratio, and LnLF/LnHF, their BP and HRV responses to HG were similar to those of the controls. In the CE study, individuals with DS exhibited lower resting LnLF and an overall lower systolic BP and mean arterial pressure compared with controls. During the CE, individuals with DS exhibited an increased diastolic BP and a smaller reduction in LnTP than controls. These differences disappeared after controlling for confounders.

Conclusions

Our results suggest that despite normal HR responses to sympathoexcitatory tasks, HRV was largely similar to controls, with some evidence of autonomic dysfunction in individuals with DS.

     

The effect of oxybutynin on cardiac autonomic modulation in healthy subjects

Purpose

The aim of this study was to assess the various doses of oral oxybutynin on cardiac autonomic modulation by measuring short-term heart rate variability (HRV) indexes during supine rest position.

Methods

Eight male healthy subjects (20–23 years) participated in the double-blind crossover randomized study. The single dose of oxybutynin (2.5, 5 and 10 mg) or placebo was given to the volunteers in four sessions within 5-day intervals. Before and minutes of 30, 60, 90 and 120 after administration, lead II electrocardiogram (ECG) was recorded for 5 min. ECG extracted RR intervals data became the base of the calculation of time domain and frequency domain HRV parameters, which indicate cardiac autonomic activity. Statistical analysis was done by using the nonparametric Wilcoxon and Kruskal–Wallis tests.

Results

The data analysis has revealed that MNN (P < 0.001), SDNN (P < 0.05), PNN50% (P < 0.01), RMSSD (P < 0.001), HFnu (P < 0.05) and LF/HF ratio (P < 0.05) values were significantly increased relative to baseline at various time points in all the groups except in placebo group. LFnu (P < 0.05) values were significantly increased relative to baseline at various time points in all the groups except in placebo group.

Conclusions

Our findings have revealed that acute consumption of 2.5, 5 and 10 mg oxybutynin (an anticholinergic compound) in the juvenile healthy male subjects produces a cholinergic effect according to time and frequency domain of HRV indexes.     

Autonomic dysfunction of overweight combined with low muscle mass

Objective

To examine the relationship between overweight combined with low muscle mass and the cardiac autonomic nervous system using heart rate variability (HRV) in healthy workers.

Methods

A total of 1,150 workers were included, with a mean age of 43.55 ± 11.45 years. The subjects were classified as low muscle mass if their appendicular skeletal muscle mass was below the 50th percentile of the study sample. Similarly, subjects were classified as overweight if their body mass index was above 25 kg/m². Electrocardiography recordings were obtained for 5 min, and the time-domain and frequency-domain indices of HRV were analyzed.

Results

Compared with the high muscle mass and non-overweight (HMM) group, the low-frequency power and the standard deviation of normal-to-normal intervals were significantly decreased in both the overweight and high muscle mass (OHMM) group and the overweight and low muscle mass (OLMM) group. The significantly decreased high-frequency (HF) power and square root of the mean squared differences of successive differences, which reflects efferent parasympathetic activity, was indicative of reduced parasympathetic modulation in the OHMM and OLMM groups. In addition, the OLMM group had a lower HF power than did the OHMM group.

Conclusions

This study suggests that HRV is reduced in overweight combined with low muscle mass group than overweight and HMM group.     

Heart rate recovery after exercise is associated with resting QTc interval in young men

Heart rate recovery (HRR) after exercise and spectral decomposition of heart rate variability (HRV), measures of autonomic nervous system function, are predictors of cardiovascular morbidity/mortality. QT interval, an index of ventricular depolarization and repolarization attained from surface ECG, is also associated with morbidity/mortality and is strongly influenced by autonomic tone. The purpose of this study was to assess the association between HRR after exercise, resting HRV and resting rate corrected QT interval in young healthy men. HRR was assessed in 37 men (23.3 ± 0.6 years) 1 minute after a graded exercise test. Resting QT interval was derived from ECG recordings and rate corrected using five formulae (Bazett, Fridericia, Hodges, Framingham, and the nomogram method of Karjalainen). Resting HRV was spectrally decomposed using an autoregressive approach. A negative correlation was detected for QTc interval and HRR for each method (r = −0.36 to −0.48, P < 0.05). There was no correlation between high frequency power of HRV (a marker of parasympathetic modulation) and QTc interval. There was a negative relationship between absolute LF power (a marker of both sympathetic and parasympathetic modulation) and QTc interval for Karjalainen, Framingham, and Bazett correction methods (r = −0.33 to −0.47, P < 0.05). Resting LF power of HRV and HRR after exercise are inversely associated with resting QTc interval in young healthy men, supporting a relationship between cardiac autonomic nervous system function and ventricular depolarization and repolarization.     

Heart rate variability associates with asymptomatic coronary atherosclerosis

Purpose

Heart rate variability (HRV) becomes impaired in symptomatic coronary artery disease (CAD), particularly, after myocardial infarction. The mechanism how CAD results in impairment of cardiac autonomic regulation is not known. Whether it results rather from coronary atherosclerosis itself than myocardial ischemia and myocardial injury has remained elusive.

Methods

Quantitative coronary angiography was performed in 30 subjects without history of myocardial ischemia, but with high familial risk for CAD. HRV was measured from 24-h ambulatory ECG recordings in time and frequency domain and also non-linear HRV variables SD1 and SD2 in Poincare plot were calculated. Myocardial ischemia was excluded by Tc-99m sestamibi scintigraphy at rest and during exercise.

Results

Coronary angiography revealed mean diameter stenosis of 32 ± 19 % in left anterior descending coronary artery, 26 ± 16 % in left circumflex coronary artery and 25 ± 20 % in right coronary artery. An inverse correlation was found between pNN50 and global severity of coronary artery diameter stenosis (r = ?0.415, p < 0.05). Correspondingly, power of HF spectral component correlated negatively with global extent of coronary atherosclerosis (r = ?0.366, p < 0.05). In Poincare plot, SD1/SD2 ratio correlated with global extent (r = ?0.394, p < 0.05) and global burden (r = ?0.388, p < 0.05) of coronary arteries.

Conclusions

The severity and extent of coronary atherosclerosis were related to a shift of cardiac autonomic regulation towards sympathetic predominance in asymptomatic subjects without evidence of myocardial ischemia.     

Autonomic changes in young smokers: acute effects of inspiratory exercise

Purpose

One of the most important consequences of smoking is the development of cardiovascular diseases. However, little is known about the early consequences of smoking and the acute effects of a single inspiratory muscle exercise session (IME). We evaluated the acute effects of an IME on cardiac parameters of young smokers.

Methods

Twelve nonsmokers (C) and fifteen smokers [S; 2.08 (1.0–3.2) pack-years] underwent an acute IME. We evaluated blood pressure (BP) and lactate, and we recorded RR interval for posterior analysis of heart rate variability (HRV), before and after IME.

Results

At baseline, systolic BP and HRV parameters in time and frequency domains were changed in S group in comparison with the C. Following IME, S group reduced systolic BP (?8 %), low frequency band (LF) (?21.4 %), LF/high frequency (HF) (?57 %), as well as increased RR variance (+105 %) and HF band.

Conclusions

Our findings indicate that a single session of inspiratory muscle exercise was able to both reduce systolic BP and improve parasympathetic and sympathetic modulations in young smokers. The results of the current study highlight the importance of furthering research on this area to better elucidate the acute and chronic effects of inspiratory muscle training on early cardiovascular and pulmonary changes of cigarette smoking.

     

Relation of heart rate recovery to heart rate variability in persons with paraplegia

Purpose  

Heart rate recovery (HRR) after treadmill exercise testing is an index of cardiac autonomic activity in non-disabled persons, but it is unknown if this is also the case in individuals with spinal cord injury (SCI). We investigated the relationship between HRR after maximal arm exercise testing and resting autonomic activity in persons with paraplegia.     

Heart rate variability measures as biomarkers in patients with psychogenic nonepileptic seizures: Potential and limitations

Heart rate variability (HRV) metrics provide reliable information about the functioning of the autonomic nervous system (ANS) and have been discussed as biomarkers in anxiety and personality disorders. We wanted to explore the potential of various HRV metrics (VLF, LF, HF, SDNN, RMSSD, cardiovagal index, cardiosympathetic index, approximate entropy) as biomarkers in patients with psychogenic nonepileptic seizures (PNES). HRV parameters were extracted from 3-minute resting single-lead ECGs of 129 subjects (52 with PNES, 42 with refractory epilepsy and 35 age-matched healthy controls). Compared with healthy controls, both patient groups had reduced HRV (all measures P < 0.03). Binary logistic regression analyses yielded significant models differentiating between healthy controls and patients with PNES or patients with epilepsy (correctly classifying 86.2 and 93.5% of cases, respectively), but not between patients with PNES and those with epilepsy. Interictal resting parasympathetic activity and sympathetic activity differ between healthy controls and patients with PNES or those with epilepsy. However, resting HRV measures do not differentiate between patients with PNES and those with epilepsy.     

Heart rate variability measures as biomarkers in patients with psychogenic nonepileptic seizures: potential and limitations

Heart rate variability (HRV) metrics provide reliable information about the functioning of the autonomic nervous system (ANS) and have been discussed as biomarkers in anxiety and personality disorders. We wanted to explore the potential of various HRV metrics (VLF, LF, HF, SDNN, RMSSD, cardiovagal index, cardiosympathetic index, approximate entropy) as biomarkers in patients with psychogenic nonepileptic seizures (PNES). HRV parameters were extracted from 3-minute resting single-lead ECGs of 129 subjects (52 with PNES, 42 with refractory epilepsy and 35 age-matched healthy controls). Compared with healthy controls, both patient groups had reduced HRV (all measures P < 0.03). Binary logistic regression analyses yielded significant models differentiating between healthy controls and patients with PNES or patients with epilepsy (correctly classifying 86.2 and 93.5% of cases, respectively), but not between patients with PNES and those with epilepsy. Interictal resting parasympathetic activity and sympathetic activity differ between healthy controls and patients with PNES or those with epilepsy. However, resting HRV measures do not differentiate between patients with PNES and those with epilepsy.     

Obstructive sleep apnea and heart rate asymmetry microstructure during sleep

Purpose

Heart rate decelerations and accelerations have unequal input to heart rate variability (HRV) and patterns created by consecutive cardiac cycles—this phenomenon is known as heart rate asymmetry (HRA). The analysis of monotonic runs of heart rate decelerations and accelerations provides a detailed insight into the HRA microstructure and thus of HRV.

Aim

To evaluate the relation between the severity of obstructive sleep apnea (OSA) and the HRA microstructure during sleep.

Methods

Seventy-eight patients with suspected OSA underwent overnight polysomnography. The 300-min ECGs from the polysomnography were selected and analyzed. The HRA microstructure was quantified by measuring (1) the contribution of monotonic runs of decelerations or accelerations of different lengths to the number of all sinus beats, and (2) the length of the longest deceleration and acceleration runs.

Results

There were 19 patients with no/mild OSA (Apnea/Hypopnea Index (AHI) 5.1 ± 2.5/h), 18 with moderate OSA (AHI 21.8 ± 4.0/h) and 41 with severe OSA (AHI 42.8 ± 17.4/h). Patients with severe OSA had significantly reduced deceleration and acceleration runs of length 1 compared to the moderate OSA group, and compared to patients with no/mild OSA they had an increased number of longer runs (from 5 to 10 for accelerations and from 5 to 8 for decelerations; p < 0.05 for all comparisons). The longest acceleration runs were significantly longer in severe OSA group (p < 0.05) than in subjects with no/mild OSA.

Conclusions

HRA microstructure is related with OSA severity. An increased number of longer deceleration and acceleration runs is more common in severe OSA patients.     

Determination of heart rate variability with an electronic stethoscope

Introduction

Heart rate variability (HRV) is widely used to characterize cardiac autonomic function by measuring beat-to-beat alterations in heart rate. Decreased HRV has been found predictive of worse cardiovascular (CV) outcomes. HRV is determined from time intervals between QRS complexes recorded by electrocardiography (ECG) for several minutes to 24 h. Although cardiac auscultation with a stethoscope is performed routinely on patients, the human ear cannot detect heart sound time intervals. The electronic stethoscope digitally processes heart sounds, from which cardiac time intervals can be obtained.

Methods

Accordingly, the objective of this study was to determine the feasibility of obtaining HRV from electronically recorded heart sounds. We prospectively studied 50 subjects with and without CV risk factors/disease and simultaneously recorded single lead ECG and heart sounds for 2 min.

Results

Time and frequency measures of HRV were calculated from R–R and S1–S1 intervals and were compared using intra-class correlation coefficients (ICC).

Conclusion

The majority of the indices were strongly correlated (ICC 0.73–1.0), while the remaining indices were moderately correlated (ICC 0.56–0.63). In conclusion, we found HRV measures determined from S1–S1 are in agreement with those determined by single lead ECG, and we demonstrate and discuss differences in the measures in detail. In addition to characterizing cardiac murmurs and time intervals, the electronic stethoscope holds promise as a convenient low-cost tool to determine HRV in the hospital and outpatient settings as a practical extension of the physical examination.     

Correlation between indexes of autonomic maneuvers and heart rate variability in hemodialysis patients

Purpose

The autonomic maneuvers are simple methods to evaluate autonomic balance, but the association between autonomic maneuvers and heart rate variability (HRV) in hemodialysis patients remains unknown. This study aimed to evaluate the correlation between HRV and respiratory sinus arrhythmia (RSA) and Valsalva maneuver (VM) indexes in hemodialysis patients and to compare two methods for RSA indexes acquisitions.

Methods

Forty-eight volunteers on hemodialysis (66.7 % men) were evaluated by VM, RSA, and 24 h Holter monitoring. At the VM, the Valsalva index (VI) was the variable considered. In the RSA, the ratio and difference between the RR intervals of inspiratory and expiratory phase (E:I and E–I, respectively) were considered by traditional form (average of respiratory cycles) and independent respiratory cycles (E:Iindep and E–Iindep). The HRV indexes evaluated were standard deviation of all normal RR intervals (SDNN), standard deviation of sequential 5-min RR interval means (SDANN), root mean square of the successive differences (rMSSD) and percentage of adjacent RR intervals with difference of duration greater than 50 ms (pNN50).

Results

The SDNN, SDANN showed significant correlation with all classic indexes of RSA (E:I: r = 0.62, 0.55, respectively, E–I: r = 0.64, 0.57, respectively), E:Iindep (r = 0.59, 0.54, respectively), E–Iindep (r = 0.47, 0.43, respectively) and VI (r = 0.42, 0.34, respectively). Significant correlation of rMSSD with E:I (r = 0.37), E–I (r = 0.41) and E:Iindep (r = 0.34) was also observed. There was no association of any variable with pNN50. Have been show high values for all variables of independent cycles method (p < 0.05).

Conclusion

The autonomic maneuvers, especially RSA, are useful methods to evaluate cardiac autonomic function in hemodialysis patients. The acquisition of the RSA index by independent cycles should not be used in this population.

     

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.     

Interval training in elderly men increases both heart rate variability and baroreflex activity

Abstract Aims Autonomic nervous system activity decreases continuously with age and appears to be a powerful predictor of disease and death. Attempts are thus made to reactivate autonomic drive with the intent of improving health. Methods We assessed maximal oxygen consumption (VO_2max), auto- nomic nervous system activity by heart rate variability (HRV) analysis and spontaneous cardiac baroreflex activity (SBR) in eleven elderly men (73.5±4.2 years) before and after a 14-week program of intensive cycloergometer interval training. The standard HRV indices were calculated using time domain (mean RR, PNN50, RMSSD, SDNN, SDANN and SDNNIDX), and Fourier transform (total power, ULF,VLF, LF, LFnu, HF, HFnu and LF/HF) analyses of 24-hour, daytime and nighttime Holter recordings. The SBR was calculated from 15-minute recordings of spontaneous blood pressure and RR interval variations using the sequence (slope, slSBR) and cross-spectral (SBR_HF and SBR_LF) methods. Results After the training period,VO_2max increased by 18.6 % (26.8±4.4 to 31.8±5.2 ml · kg^–1 · min^–1, p<0.01). The nocturnal parasympathetic indices of HRV increased (PNN50: 3.05±2.21 to 5.00±2.87%, RMSSD: 29.1±7.6 to 38.8±10.9 ms, HF: 117±54 to 194±116 ms²/Hz, all p<0.05) as did the SBR indices (slSBR: 7.0±1.8 to 9.8±2.1 ms·mmHg^–1, p<0.01; SBR_HF: 6.9±2.2 to 10.5±3.7 ms ·mmHg^–1, p<0.05; SBR_LF: 5.3±2.3 to 6.9±3.1 ms ·mmHg^–1, p=0.22). Conclusion Intensive endurance training in elderly men enhanced parasympathetic parameters of HRV and, interestingly, of SBR. Physiological mechanisms and long-term clinical effects on health status should be further investigated.     

Threat-induced autonomic dysregulation in panic disorder evidenced by heart rate variability measures

Objective

The objective was to compare autonomic response to threatening stimuli between patients with panic disorder (PD) and healthy volunteers by using 5-min recordings of heart rate variability (HRV).

Methods

Twenty-seven patients with PD and 20 healthy controls were recruited. The first 5-min measurement of HRV was conducted at resting state. HRV measurement during threatening stimuli was conducted while participants were viewing 15 threatening pictures. Spectral analyses measures included high-frequency (HF; 0.15–0.4 HZ) component, low-frequency (LF; 0.04–0.15 Hz) component and LF/HF ratio.

Results

There was no significant HRV difference between the two groups at the resting state. During threatening stimuli, the PD group had significantly higher LF power and LF/HF ratio and significantly lower HF power than the healthy controls (for all, P< .01). A two-way analysis of variance was employed to determine the effect of group (patient and control) and condition (threatening and resting) on all three HRV measures. The analysis showed a significant main effect of group (F= 12.21; P< .01), condition (F= 14.21; P< .001) and interaction effect between group and condition (F= 4.83; P< .05) on LF/HF ratio.

Conclusions

The findings from the present study suggest that patients with PD exhibit a sympathetic predominance when faced with threatening stimuli compared with normal control subjects.