Cardiac Autonomic Indices Research Articles

Neuro-Cardiovascular Responses to Sympathetic Stimulation in Fighter Pilots.

INTRODUCTION: The chronic effects of regular exposure to high acceleration levels (G-force) on the neuro-cardiovascular system are unclear. We compared the mean arterial pressure (MAP) and cardiac autonomic modulation between nonpilots (NP) vs. military fighter (FP) and transport (TP) pilots. Additionally, we correlated the cardiac autonomic indices with the cardiorespiratory fitness and flight experience of FP.METHODS: A total of 21 FP, 8 TP, and 20 NP performed a tilt test (TT), during which beat-to-beat blood pressure and heart rate were recorded.RESULTS: No difference was detected between groups for changes in MAP and heart rate variability indices during the TT. However, the analysis of areas under the curves showed a greater increase in MAP in FP vs. TP and NP. Conversely, there was a greater decrease in indices reflecting vagal modulation in TP vs. FP and NP (rMSSD, pNN50, and SDNN), and a greater increase in heart rate and sympathovagal balance in TP vs. other groups (LF/HF). The maximal oxygen uptake was strongly correlated with the vagal reserve in FP (r = -0.74). Moreover, the total flying hours of FP were positively correlated with resting HFnu (r = 0.47) and inversely correlated with resting LFnu (r = -0.55) and LF/HF (r = -0.46).CONCLUSION: FP had a higher pressor response to TT than TP and NP. Vagal withdrawal and sympathovagal increase induced by TT in FP were similar vs. NP and attenuated vs. TP. Greater cardiorespiratory fitness and accumulated flying hours in FP seemed to favor lower sympathetic and greater vagal modulation at rest.dos Santos Rangel MV, de Sá GB, Farinatti P, Borges JP. Neuro-cardiovascular responses to sympathetic stimulation in fighter pilots. Aerosp Med Hum Perform. 2023; 94(10):761-769.

Soluble interleukin-1 receptor type 2 plasma levels in Parkinson's disease: relationship with cardiac autonomic profile before and after peripheral mechanical somatosensory stimulation.

Introduction: Systemic inflammation promotes neurodegeneration in Parkinson's disease (PD). Interleukin-1 receptor type 2 (sIL-1R2) plasma levels increase during inflammation. Data on sIL-1R2 in PD patients and its relationship with PD cardiac autonomic profile are limited, given the possible anti-inflammatory effect of vagal activation. Previously, automated mechanical peripheral somatosensory stimulation (AMPSS) enhanced cardiac vagal modulation. Objectives were to 1) evaluate sIL-1R2 plasma concentrations in PD patients and healthy controls and 2) investigate the correlations between sIL-1R2 and cardiac autonomic indices obtained by spectrum analysis of heart rate variability before and after AMPSS. Methods: sIL-1R2 plasma levels were assessed in 48 PD patients and 50 healthy controls. Electrocardiogram and beat-by-beat arterial pressure were recorded at baseline and after 5 AMPSS sessions in 16 PD patients. Results: PD patients had higher sIL-1R2 levels than controls. In the PD subgroup, an inverse correlation between sIL-1R2 and HFnu was found. There was a negative correlation between changes induced by AMPSS on HFnu and sIL-1R2. Discussion: Higher sIL-1R2 levels in PD patients reflect the inflammatory dysregulation associated with the disease. In PD patients, higher sIL-1R2 was associated with reduced cardiovagal tone. Increased cardiovagal modulation following AMPSS was associated with lower sIL-1R2 levels in Parkinson's disease patients, suggesting inflammatory state improvement.

Response and Adaptation of the Cardiac Autonomic System to Functional High-intensity Interval Training with Respiratory Facemasks: Impacts of the Training Period and Facemask Modality During a COVID-19 Pandemic

Background: Following the SARS-CoV-2 pandemic in 2019, medical face masks were widely recommended for large numbers of people and for long periods of time. The effect of wearing surgical and N95 face masks during long-term high-intensity interval training on the cardiac autonomic system has not been reported. Methods: Eighteen healthy men were randomly divided into three groups (surgical mask, N95 mask, and no mask) and performed high-intensity interval training with (80 - 90%-heart rate max) intensity three times a week, three repetitions in a session for four weeks. Heart rate variability parameters were evaluated with an electrocardiogram device and Kubius software. The R-R interval was recorded for 5 minutes in a sitting position in the pre-and post-modified Bruce test before and after four weeks of interval training to extract parasympathetic (RMSSD, HF, SD1), sympathetic indices (LF, LF/HF) and RR mean. We used the two-way ANOVA test and the Bonferroni post hoc test. Results: In all groups, four-week functional HIIT exercises increased the resting parasympathetic indices (RMSSD, SD1) compared to baseline levels. This increase was more evident in the N95 mask group than in the surgical mask group. In addition, the five-minute recovery of the cardiac autonomic system after a modified Bruce test following functional HIIT exercise increased parasympathetic tone (RMSSD, HFn.u) in all groups compared to baseline levels. Therefore, a four-week adaptation to HIIT exercises leads to faster recovery of sympathetic indices (LFn.u, LF/HF) in the no mask group, as compared to the surgical and N95 groups. Despite the above, there was no significant difference in the recovery and resting values of cardiac autonomic system indices between the two types of surgical masks and N95 compared to the control group (no mask). Conclusions: Four weeks of high-intensity interval training using surgical and N95 face masks improved the cardiac autonomic nervous system. This data is important for recommending the use of face masks during physical activity.

Physical Activity Trajectories, Autonomic Balance and Cognitive Function: the CARDIA Study

AbstractBackgroundPhysical activity (PA), and particularly moderate to vigorous intensity PA (MVPA), may protect against cognitive decline. However, the underlying mechanisms are not fully understood. Cardiac autonomic balance is influenced by PA and implicated in dementia pathogenesis. Therefore, the study aimed to examine whether autonomic balance mediates the association between PA and cognitive function.MethodThe sample included 1,939 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study. MVPA was obtained in 7 consecutive examinations from baseline (1985‐86; 18‐30 years) to the Year 20 exam. Cardiac autonomic balance was assessed at Year 20 via resting heart rate, and via measures of heart rate variability: standard deviation normal to normal (SDNN) and root mean square of successive differences (RMSDD). A comprehensive cognitive assessment was performed at Year 30. Group‐based trajectory modeling was used to identify homogenous MVPA trajectory groups, and formal mediation analysis was used to test whether cardiac autonomic function indices lie on the causal pathway between MVPA trajectories and cognitive function.ResultThree distinct PA trajectory patterns were identified: (1) Below MVPA guidelines (n = 1,122; 57.9%); (2) Meeting MVPA guidelines (n = 652; 33.6%); and (3) Exceeding MVPA guidelines (n = 165; 8.5%) (Figure). Meeting and exceeding MVPA guidelines were related to lower resting heart rate and higher heart rate variability, which indicate improved autonomic balance. Meeting and exceeding MVPA guidelines were additionally associated with improved semantic fluency performance. The association between higher MVPA level and semantic fluency performance was fully mediated by RMSDD and partially mediated by SDNN. No additional associations were observed between MVPA trajectories and other cognitive outcomes, and no statistically significant mediation by autonomic balance indices was found for these associations (Table).ConclusionHigher MVPA levels across the young adult to midlife transition were associated with better cardiac autonomic function, which in turn explained some of the associations between PA trajectories and better semantic fluency performance. Future studies, particularly among older individuals are warranted to clarify the role of autonomic balance in the link between physical activity and brain health. These findings may lead to more targeted PA recommendations across the life‐course to slow cognitive decline and decrease dementia risk.

A Machine Learning Approach for Detecting Idiopathic REM Sleep Behavior Disorder.

Background and purpose: Growing evidence suggests that Machine Learning (ML) models can assist the diagnosis of neurological disorders. However, little is known about the potential application of ML in diagnosing idiopathic REM sleep behavior disorder (iRBD), a parasomnia characterized by a high risk of phenoconversion to synucleinopathies. This study aimed to develop a model using ML algorithms to identify iRBD patients and test its accuracy. Methods: Data were acquired from 32 participants (20 iRBD patients and 12 controls). All subjects underwent a video-polysomnography. In all subjects, we measured the components of heart rate variability (HRV) during 24 h recordings and calculated night-to-day ratios (cardiac autonomic indices). Discriminating performances of single HRV features were assessed. ML models based on Logistic Regression (LR), Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) were trained on HRV data. The utility of HRV features and ML models for detecting iRBD was evaluated by area under the ROC curve (AUC), sensitivity, specificity and accuracy corresponding to optimal models. Results: Cardiac autonomic indices had low performances (accuracy 63-69%) in distinguishing iRBD from control subjects. By contrast, the RF model performed the best, with excellent accuracy (94%), sensitivity (95%) and specificity (92%), while XGBoost showed accuracy (91%), specificity (83%) and sensitivity (95%). The mean triangular index during wake (TIw) was the best discriminating feature between iRBD and HC, with 81% accuracy, reaching 84% accuracy when combined with VLF power during sleep using an LR model. Conclusions: Our findings demonstrated that ML algorithms can accurately identify iRBD patients. Our model could be used in clinical practice to facilitate the early detection of this form of RBD.

Differences in autonomic heart rate modulation during rest and after a supramaximal anaerobic test in relation to gender and the menstrual cycle in women

Background/Aim. Heart rate variability (HRV) and heart rate recovery (HRR) show differences between genders, and dissimilarities were also reported in women in various menstrual cycle (MC) phases. The aim of this research was to analyze cardiac autonomic indices during rest and in re-covery after the Wingate test between genders in the young, sedentary population and to investigate whether a MC phase in women can influence these indi-ces. Methods. Twenty-five females (20.5 ? 0.7 years) and sixteen males (20.4 ? 0.7 years) performed the Wingate anaerobic test on a cycle ergometer while their HRR and resting and recovery HRV indices were obtained. In fe-males, data were collected during three distinctive MC phases. Results. The natural logarithm of low-frequency (lnLF) HRV marker and the natural logarithm of high-frequency (lnHF) HRV marker were higher in males dur-ing rest compared to women in all MC phases, except in the late follicular phase, where no differences in lnHF be-tween genders were observed. Markedly higher lnLF and lnHF were recorded in males after the Wingate test. There were no differences in HRV between women in various MC phases during rest. Surprisingly, parasympathetic time-domain marker (the square root of the mean squared dif-ferences of successive NN intervals, RMSSD) and lnLF were both higher in the early follicular phase in compari-son to the luteal phase of MC during recovery. HRR was faster in men in comparison to women in all MC phas-es. Conclusion. Males show greater HRR and total varia-bility during rest and recovery, but it appears that resting parasympathetic activity is similar when females are in the late follicular phase of MC. Intra-female resting autonomic variability is not affected by the sex hormonal cycle. Post-exercise HRV in the early follicular phase reflects a signifi-cantly favourable autonomic profile in comparison to the luteal phase of MC.

The relationship between QT interval indices with cardiac autonomic neuropathy in diabetic patients: a case control study

BackgroundLong QT interval (QT) and abnormal QT dispersion (QTd) are associated with sudden death. The relationship between cardiac autonomic neuropathy (CAN) and QT indices in type 2 diabetic patients were investigated.MethodsTotally 130 diabetic subjects (mean age 50.87 ± 13.9 years) were included (70 individuals with and 60 individuals without CAN). All participants had sinus cardiac rhythm. The patients who had diseases or take drugs that cause orthostatic hypotension (OH), cardiac arrhythmia and QT prolongation were excluded. After interview and examination, standard and continuous ECG was taken in supine position with deep breathing and standing up position. CAN diagnosis was based on Ewing’s tests. QT, QT corrected (QTc), minimum QT (QT min), maximum QT (QT max) and mean ± SD of QT (QT mean) and QTd were assessed from standard ECG. QTc was calculated by Bazett’s formula from V2 lead. QTc > 440 ms in men and QTc > 460 ms in women and QTd > 80 ms were considered abnormal.ResultsIn patients with CAN, 21.5% were symptomatic. The prevalence of abnormal QTc and QTd was 11.3% and 28.7%, respectively. There was no significant difference between the patients with or without CAN in terms of long QTc and abnormal QTd. However, the mean ± SD of QT max, QT mean and QTd was higher in the patients with CAN (P value < 0.03). The used cut points for QTc and QTd have high specificity (79% for both) and low sensitivity (30% and 37%, respectively). To use QTc and QTd as screening test for CAN in T2DM patients, the cutoff points 380 and 550 ms are suggested, respectively.ConclusionThe prevalence of asymptomatic CAN was 3.7 times that of symptomatic CAN. In patients with CAN the QT max, QT mean and QTd were higher than those without CAN. There was no association between CAN and long QTc and abnormal QTd.

Association of Severity of Autism Spectrum Disorder with Cardiac Autonomic Indices in Children

Background &amp; Objectives: Autism Spectrum Disorder (ASD) being a complex neuro-developmentaldisorder is found to be associated with Autonomic Nervous System (ANS) dysfunction. The sympathovagalcontinual dynamic excitatory- inhibitory interactions leads to Heart Rate Variability (HRV) which isan index of cardiac autonomic regulation. Aim of the study was to evaluate cardiac autonomic regulation inchildren with ASD at rest using short-term HRV analysis and to correlate it with severity of autism.Methods: A total of 30 subjects were evaluated in the study comprising of 15 ASD children and 15 healthycontrols. A five minutes recording of resting ECG was carried out from which R-R intervals were procuredand HRV indices were analysed. Frequency domain analysis of HRV was carried out and the followingparameters were evaluated: Spectral powers in low frequency (LF) bands, High frequency (HF) bands, totalpower (TP), LF/HF ratio and average heart rate (HR) were evaluated. HRV indices between the groups werecompared using Student’s t test. Severity of autism was correlated with the evaluated HRV indices usingPearson correlation test.Results: Cardiac sympathetic activity as assessed by low frequency power spectrum (‘p’ value 0.034) andtotal power (‘p’ value 0.023) of the HRV spectrum was significantly higher in autistic children comparedto that of normal controls. However, the association between severity of ASDs and HRV indices were notstatistically significant.Conclusion: Study concludes that here was no significant association between HRV indices and severity ofautism.

Alterations in Cardiac Vagal Modulation-to-Vagal Tone Ratio in response to accumulated exercise stress in intermittent team sport

Summary Study aim: This investigation examined the cardiac vagal modulation-to-vagal tone ratio and its utility to represent the dose response to accumulated exercise stress in intermittent team sport. Material and methods: Fourteen international calibre female field hockey players training as part of a national team were participants over a three-week period. Exercise stress was expressed through cardiovascular strain using heart rate (HR) dynamics and was quantified as a training load (AU) and time spent exercising above anaerobic threshold (min). Cardiac autonomic activity was examined using heart rate variability; R-R intervals (ms) were collected immediately upon awakening throughout each weekend. The square root of the mean squared differences of successive R–R intervals were individually calculated, and log transformed prior to being averaged (Ln rMSSD) along with the corresponding mean R-R interval length. Multiple linear regression analysis examined the association between cardiac autonomic activity and indices of accumulated exercise stress. Results: Significant inverse associations (95% CI) between the Ln rMSSD:R-R ratio and both training load [r = –0.48 (–0.70: –0.18), p = 0.012] and time spent exercising above anaerobic threshold [r = –0.51 (–0.72 : –0.22), p = 0.006] were observed. The association between mean R-R interval length and Ln rMSSD was not significant [r = 0.05, p = 0.950]. Conclusion: The current study demonstrated high intensity exercise, as defined through time spent above anaerobic threshold, displayed a stronger association with the Ln rMSSD:R-R ratio compared to a HR-derived training load when examining the dose response to accumulated intermittent exercise.

Electrocardiographic and Cardiac Autonomic Indices - Implications of Sex-Specific Risk Stratification in Women After Acute Myocardial Infarction.

The debate on whether sex-specific predictive models improve risk stratification after myocardial infarction is ongoing. This review summarises the current clinical knowledge on sex-specific differences in post-infarction risk stratification parameters. Particular focus is given to electrocardiographic risk factors and indices of cardiac autonomic status. Differences in the underlying pathophysiology between men and women are known. However, clinical findings often lead to uncertain conclusions for a number of risk predictors including, among others, resting heart rate, heart rate variability, heart rate turbulence, QT interval duration, and QRS-T angle. The review links recent findings in prognostic parameters with successful approaches in sex-specific non-invasive risk stratification. Disparities are described in the current clinical opinions on the relevance of investigated parameters in women and possible directions for further research in the field are given.

OP-097 Latency and Velocity of Pupil Contraction Assessed by Dynamic Pupillometry Predict Cardiac Autonomic Indices among Healthy Subjects

OP-097 Latency and Velocity of Pupil Contraction Assessed by Dynamic Pupillometry Predict Cardiac Autonomic Indices among Healthy Subjects

Correlates of Heart Rate Measures with Incidental Physical Activity and Cardiorespiratory Fitness in Overweight Female Workers.

Previous studies have suggested that physical activity (PA) levels and cardiorespiratory fitness (CRF) impact on the autonomic control of heart rate (HR). However, previous studies evaluating PA levels did not discriminate between incidental PA and regular exercise. We hypothesized that incidental PA “per se” would influence cardiac autonomic indices as assessed via HR variability (HRV) and HR recovery (HRR) in non-exercisers. Thus, the objective of this study was to investigate the relationships between objective PA levels, CRF, and cardiac autonomic indices in adult, regular non-exercising female workers. After familiarization with procedures and evaluation of body composition, 21 women completed a submaximal cycling test and evaluation of HRR on four different days. Resting (2-min seated and standing) and ambulatory (4-h) HRV were also recorded. Levels of PA were assessed by accelerometry over five consecutive days (i.e., Wednesday to Sunday). Maximum oxygen consumption (VO2max) was measured as an index of CRF. As reliability was low to moderate for most HR measures, relationships between these and PA and CRF were examined using the 4-day average measures. Significant correlations were identified between post-exercise HRR in the first min with various PA indices (daily moderate PA, daily vigorous PA, and the sum of vigorous and very vigorous daily PA). Additionally, VO2max was significantly correlated to HRV but not to HRR. The current results indicated that CRF was influential in enhancing HRV while incidental or non-exercise based PA was associated with greater autonomic reactivation in adult overweight women. Therefore, both CRF and non-exercise based PA contribute significant but diverse effects on cardiac health. The use of 4-day averages instead of single measures for evaluation of autonomic control of HR may provide a better indication of regular cardiac autonomic function that remains to be refined.

Poor glycemic control impacts linear and non-linear dynamics of heart rate in DM type 2

INTRODUCTION: It is well known that type 2 diabetes mellitus (T2DM) produces cardiovascular autonomic neuropathy (CAN), which may affect the cardiac autonomic modulation. However, it is unclear whether the lack of glycemic control in T2DM without CAN could impact negatively on cardiac autonomic modulation. Objective: To evaluate the relationship between glycemic control and cardiac autonomic modulation in individuals with T2DM without CAN. Descriptive, prospective and cross sectional study.METHODS: Forty-nine patients with T2DM (51±7 years) were divided into two groups according to glycosylated hemoglobin (HbA1c): G1≤7% and G2&gt;7.0%. Resting heart rate (HR) and RR interval (RRi) were obtained and calculated by linear (Mean iRR; Mean HR; rMSSD; STD RR; LF; HF; LF/HF, TINN and RR Tri,) and non-linear (SD1; SD2; DFα1; DFα2, Shannon entropy; ApEn; SampEn and CD) methods of heart rate variability (HRV). Insulin, HOMA-IR, fasting glucose and HbA1c were obtained by blood tests.RESULTS: G2 (HbA1c≤7%) showed lower values for the mean of iRR; STD RR; RR Tri, TINN, SD2, CD and higher mean HR when compared with G1 (HbA1c &gt; 7%). Additionally, HbA1c correlated negatively with mean RRi (r=0.28, p=0.044); STD RR (r=0.33, p=0.017); RR Tri (r=-0.35, p=0.013), SD2 (r=-0.39, p=0.004) and positively with mean HR (r=0.28, p=0.045). Finally, fasting glucose correlated negatively with STD RR (r=-0.36, p=0.010); RR Tri (r=-0.36, p=0.010); TINN (r=-0.33, p=0.019) and SD2 (r=-0.42, p=0.002).CONCLUSION: We concluded that poor glycemic control is related to cardiac autonomic modulation indices in individuals with T2DM even if they do not present cardiovascular autonomic neuropathy.

The Assessment of the Autonomic Response to Acute Stress Using Electrodermal Activity

Abstract The response of autonomic nervous system to mental stress is currently studied as a key role factor in the pathophysiology of stress related diseases. Altered autonomic regulation can result in increased morbidity, potentially affecting (directly or indirectly) any of the organs. Cardiovascular system (CVS) is one of the most sensitive systems to the effect of autonomic outputs. The predictive value of the laboratory stress tests was proved in several studies with CVS pathology. In this study we aimed to assess the autonomic reactivity to different mental stressors (cognitive and emotional) in healthy subjects using electrodermal activity (EDA) as a sensitive psychophysiological marker of sympathetic activity. We found significantly increased EDA in response to all the mental tasks with decrease of the values during recovery periods. However, EDA did not return to the baseline values during recovery periods, potentially indicating the sympathetic arousal during complete stress profile protocol. We suggest EDA presents a well applicable marker of the sympathetic activation, offering a different information about central regulation processes regarding the sympathetic activity compared to cardiac autonomic indices.

Functional connectivity between parietal cortex and the cardiac autonomic system in uremics

Although the central autonomic network (CAN) has been well researched in animal models, the CAN in humans is still unclear, especially for cardiovascular control. This study aimed to investigate which areas of the cerebral cortices are associated with the peripheral cardiac autonomic control involved in the CAN in uremic patients with autonomic dysfunction and normal controls. The central and peripheral autonomic network in 19 uremic patients with significant autonomic dysfunction and 24 age- and sex-matched controls [mean age ± standard deviation (SD), 55.16 ± 10.45 years and 55.42 ± 5.42 years, respectively] were evaluated by simultaneous spectral analysis of electroencephalography (EEG) and electrocardiography recording (ECG), along with serial autonomic tests [autonomic questionnaire and orthostatic blood pressure (BP) change]. Only frequency-domain heart rate variability (f-HRV) during the deep-breathing stage could differentiate the two groups. Although there is no significant difference in f-HRV during the quiet-breathing stage, different patterns of central oscillation and their correlation with peripheral cardiac autonomic indices could be found for the two groups. Although the power of specific EEG bands under electrode T3 and T6 correlated significantly with the power of peripheral HRV indices in the control group, those under electrodes P3 and Pz had significant correlations in the uremic group suggesting a role of functional connectivity between them. In addition, sympathetic activity is correlated with slow wave EEG (theta/delta) power whereas parasympathetic activity is correlated with fast wave EEG (beta) power. In conclusion, there is functional connectivity between the parietal cortex and the peripheral cardiac autonomic system (PAN) in uremics and the pattern of central autonomic connectivity differs between uremic patients with autonomic dysfunction and normal controls.

Longitudinal changes in cardiac autonomic function and aerobic fitness indices in endurance runners: A case study with a high-level team

To determine the effects of preparatory phase training on aerobic parameters, resting heart rate variability (HRV) and 5-km performance of high-level endurance runners and the relationship between the percentage change (% change) of resting HRV with the % change of aerobic parameters and 5-km performance. Six runners were assessed before and after seven weeks of training. The aerobic parameters were determined in an incremental test. The HRV was assessed by a heart rate monitor. Athletes performed a 5-km running test in a track. The analysis revealed ‘likely’ and ‘very likely’ improvements for velocity associated with maximal oxygen uptake (O2max) (20.0±1.0 km·h−1 to 21.2±0.6 km·h−1) and 5-km performance (18.0±0.4 km·h−1 to 18.9±0.7 km·h−1), respectively, as well as ‘likely’ decrease in high frequency (41.4±18.5 nu to 30.4±14.3 nu), and increase in low frequency (58.5±18.5 nu to 69.6±14.3 nu) band densities. The variation in the velocity associated with O2max showed the highest correlation with 5-km performance (r=0.95). The % change in the square root of the mean sum of the squared differences between R–R intervals and standard deviation 1 were highly correlated with variation in 5-km performance (r=0.69 and 0.66). Changes in the velocity associated with O2max and vagally mediated HRV were highly associated with 5-km running performance within the investigated team. These results have important implications because these parameters can be assessed longitudinally to monitor adaptation to training.

Evaluation of various cardiac autonomic indices in patients with familial Mediterranean fever on colchicine treatment

BackgroundFamilial Mediterranean fever (FMF) is characterized by sporadic, acute attacks of fever and serositis. Cardiovascular involvement is one of the leading cause of morbidity and mortality among FMF patients. Herein, we aimed to evaluate cardiac autonomic functions in FMF patients without overt cardiac symptoms. MethodsWe enrolled 38 patients (20 female; mean age 34.4±10.2 years) with FMF and 34 healthy subjects (18 female; mean age 33.2±9.3 years). All participants underwent 24-hour Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting first, second, and third minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV), heart rate turbulance (HRT) and QT dispersion analysis. The mean FMF duration was 9.8±4.2 years. ResultsBoth groups were similar with regard to baseline characteristics. Mean HRR1 (p=0.001), HRR2 (p=0.003) and HRR3 (p<0.001) were significantly lower in FMF group. SDNN (standard deviation of all NN intervals), SDANN (SD of the 5min mean RR intervals), RMSSD (root square of successive differences in RR interval), and PNN50 (proportion of differences in successive NN intervals >50ms) and high-frequency (HF) components were significantly decreased, but low frequency (LF) and LF/HF were significantly higher in FMF patients. HRT onset and slope were significantly less negative in FMF patients. Also, QTd was significantly higher in FMF patients (p<0.001). ConclusionPatients with FMF showed delayed recovery of heart rate and abnormal HRV and HRT parameters with respect to normal subjects. Cardiac autonomic functions might be involved in FMF patients even in patients without cardiac symptoms.

Cardiac Autonomic Functions Derived From Short-Term Heart Rate Variability Recordings Associated With Nondiagnostic Results of Treadmill Exercise Testing

Analysis of short-term (5-minute) heart rate variability (HRV) may provide useful information about autonomic nervous control of the cardiovascular system. The aim of the present study was to evaluate the association between the results of treadmill exercise testing (TET) and short-term (5-minute) HRV. Patients undertaking TET were anteriorly evaluated with short-term (5-minute) HRV over time (SDNN, RMSSD, NN50 count, pNN50) and frequency (LF, HF, total power) domains. Among 414 patients, 32 individuals (7.7%; 14 men) had nondiagnostic results. The nondiagnostic group had older age, higher body mass index, more hypertension, lower SDNN, lower LF, and higher HF than the negative group. After adjustment for potential confounders, SDNN (OR 0.94, 95% CI 0.91-0.97; P = 0.01), RMSSD (OR 0.96, 95% CI 0.93-0.99; P = 0.02), NN50 count (OR 0.98, 95% CI 0.97-1.00; P = 0.04) and LF (OR 0.96, 95% CI 0.96-0.99; P = 0.03) were negatively related to nondiagnostic results, and HF showed a positive effect (OR 1.04, 95% CI 1.01-1.05; P = 0.02). No HRV indices were significantly associated with positive results. Our study suggested that cardiac autonomic indices derived from short-term HRV recordings might predict nondiagnostic results of TET.

Fysiologische stressmetingen in de werksituatie: nut, beperkingen en bevindingen

Physiological stress measures at work: relevance, limitations, and findings Physiological stress measures at work: relevance, limitations, and findings L. van Doornen &amp; J. Houtveen, Gedrag &amp; Organisatie, volume 22, September 2009, nr. 3, pp. 275-293 Physiological stress measures should only to a limited extent be considered as 'objective' indices of subjectively experienced work stress. Their contribution should mainly be sought in the quantification of the load on the body exerted by stress, the latter being the mediator of the health effects of work stress. For the most widely used physiological parameters in the field of work stress – blood pressure, heart rate, cardiac autonomic indices, adrenalin and cortisol – their physiology is described, their measurement techniques outlined, and an overall picture furnished with respect to differences observed between high- and low-work stress populations. Finally some suggestions are given with respect to future directions this field may take: focus on individual differences in physiological stress-sensitivity; quantification of recovery, and quantification of the effects of individual or workplace interventions.

Daily Variation of Particulate Air Pollution and Poor Cardiac Autonomic Control in the Elderly

examined the cardiac autonomic response to daily variations in PM in 26 elderly (mean age 81) individuals for 3 consecutive weeks. Several standardized methods were used to measure 24-hr average PM concentrations prior to the clinical test inside (indoor PM2.5) and immediately outside (outdoor PM2.5 and PM2.5-10) of participants' residences. Resting, supine, 6-min R wave to R wave (R-R) interval data were collected to estimate high frequency (0.15-0.40 Hz) and low frequency (0.04-0.15 Hz) powers and standard deviation of normal R-R intervals (SDNN) as cardiac autonomic control indices. Participant-specific lower heart rate variability days were defined as days for which the high-frequency indices fell below the first tertile of the individual's high-frequency distribution over the study period. Indoor PM2.5 &gt; 15 microg/m3 was used to define high pollution days. Results show that the odds ratio (95% confidence interval) of low heart rate variability high frequency for high (vs. not high) pollution days was 3.08 (1.43, 6.59). The ss-coefficients (standard error) from mixed models to assess the quantitative relationship between variations in indoor PM2.5 and the log-transformed high frequency, low frequency, and SDNN were: -0.029 (0.010), -0.027 (0.009), and -0.004 (0.003), respectively. This first study of cardiac autonomic control response to daily variations of PM2.5 indicates that increased levels of PM2.5 are associated with lower cardiac autonomic control, suggesting a possible mechanistic link between PM and cardiovascular disease mortality.