Changes In Cardiac Autonomic Function Research Articles

Impact of COVID-19 on cardiac autonomic function in healthy young adults: potential role of symptomatology and time since diagnosis.

Emerging evidence suggests that COVID-19 may affect cardiac autonomic function; however, the limited findings in young adults with COVID-19 have been equivocal. Notably, symptomology and time since diagnosis appear to influence vascular health following COVID-19, but this has not been explored in the context of cardiac autonomic regulation. Therefore, we hypothesized that young adults who had persistent symptoms following COVID-19 would have lower heart rate variability (HRV) and cardiac baroreflex sensitivity (BRS) compared with those who had COVID-19 but were asymptomatic at testing and controls who never had COVID-19. Furthermore, we hypothesized that there would be relationships between cardiac autonomic function measures and time since diagnosis. We studied 27 adults who had COVID-19 and were either asymptomatic (ASYM; n = 15, 6 females); 21 ± 4 yr; 8.4 ± 4.0 wk from diagnosis) or symptomatic (SYM; n = 12, 9 females); 24 ± 3 yr; 12.3 ± 6.2 wk from diagnosis) at testing, and 20 adults who reported never having COVID-19 (24 ± 4 yr, 11 females). Heart rate and beat-to-beat blood pressure were continuously recorded during 5 min of rest to assess HRV and cardiac BRS. HRV [root mean square of successive differences between normal heartbeats (RMSSD); control, 73 ± 50 ms; ASYM, 71 ± 47 ms; and SYM, 84 ± 45 ms; P = 0.774] and cardiac BRS (overall gain; control, 22.3 ± 10.1 ms/mmHg; ASYM, 22.7 ± 12.2 ms/mmHg; and SYM, 24.3 ± 10.8 ms/mmHg; P = 0.871) were not different between groups. However, we found correlations with time since diagnosis for HRV (e.g., RMSSD, r = 0.460, P = 0.016) and cardiac BRS (overall gain, r = 0.470, P = 0.014). These data suggest a transient impact of COVID-19 on cardiac autonomic function that appears mild and unrelated to persistent symptoms in young adults.NEW & NOTEWORTHY The potential role of persistent COVID-19 symptoms on cardiac autonomic function in young adults was investigated. We observed no differences in heart rate variability or cardiac baroreflex sensitivity between controls who never had COVID-19 and those who had COVID-19, regardless of symptomology. However, there were significant relationships between measures of cardiac autonomic function and time since diagnosis, suggesting that COVID-19-related changes in cardiac autonomic function are transient in young, otherwise healthy adults.

Training-related Changes In Cardiac Autonomic Function Assessed Before And After Graded Exercise Testing

Aerobic training improves cardiac autonomic function, leading to increased heart rate variability (HRV) and decreased heart rate (HR) at rest. Intense exercise such as graded exercise testing (GXT) acutely increases HR and decreases HRV, which eventually return to resting levels post-exercise. Autonomic recovery after exercise may improve with training. PURPOSE: To examine the relationship between HRV and HR before and after GXT, and to assess changes resulting from 18 weeks of aerobic training. METHODS: Healthy young adults (n = 12, 7f; age 20.9 ± 0.6) completed physiological testing prior to enrollment in a marathon training course, and again after training. Testing included a 10-minute seated monitoring of HR/HRV (REST) with a Polar RS800cx watch and chest-strap, followed by GXT, and a 20-minute seated recovery period with HR/HRV monitoring. Recovery data were divided into two 10-minute segments (REC1 and REC2) for analysis. Mean HR and the following HRV measures were assessed using Kubios HRV Version 3.3: Standard deviation (SDNN), root mean square of the successive differences (RMSSD), high frequency power (HF), low frequency power (LF), low frequency to high frequency ratio (LF/HF), sample entropy (SE), and detrended fluctuation analysis α1 (DFAα1) and α2 (DFAα2). Repeated measures ANOVA was used to compare 10-minute segments (REST, REC1, and REC2) and to assess changes with training. RESULTS: All HRV measures and HR were different between segments (p ≤ 0.05), with HR lowest during REST and highest during REC1. Similarly, HRV measures reflected greatest variability during REST and lowest during REC1. Several measures of HRV, as well as HR changed with training. Heart rate decreased (p = 0.023) at REST (75.0 ± 17.3, 70.1 ± 14.2 bpm), during REC1 (106.3 ± 13.7, 100.1 ± 10.7) and REC2 (102.8 ± 11.9, 95.6 ± 10.3). With training, RMSSD increased (REST: 56.5 ± 29.3, 64.7 ± 32.4 ms; REC1: 6.8 ± 3.4, 8.5 ± 4.5; REC2: 9.4 ± 4.5, 11.1 ± 4.1; p = 0.048). Similarly, HF (p = 0.031) and DFAα1 (p = 0.017) exhibited greater variability across the three segments after training. CONCLUSIONS: Differences in cardiac autonomic function between timepoints before and after GXT were observed. Aerobic training reduced HR and increased selected HRV variables.

A 12-month lifestyle intervention does not improve cardiac autonomic function in patients with chronic kidney disease.

Patients with chronic kidney disease (CKD) are at a high risk of future autonomic dysfunction and cardiovascular disease. The aim of this study was to examine the effects of a 12-month lifestyle intervention (LI) involving regular aerobic exercise on cardiac autonomic function in CKD patients. Pooled exploratory analysis. 113 eligible patients with stage 3-4 CKD (eGFR 25-60ml/min/1.75m2) participated in a LI program, including an 8-week individualised gym-based exercise program followed by a 10-month home-based program. The control (CON) group underwent standard nephrological care. The following parameters were assessed prior to and following the 12-month study period: cardiorespiratory fitness (VO2peak) from a graded exercise test; cardiac autonomic function from time, frequency, and non-linear measures of heart rate variability (HRV), heart rate (HR) recovery following peak exercise, and chronotropic competence during exercise. Compared to the CON group, the LI group significantly increased VO2peak (CON=-1.0 vs. LI=+1.8ml/kg/min, p<0.01) while there was no significant improvement in any HRV measure (p=0.85), HR recovery (p=0.38) or chronotropic competence (p=0.28). Changes in relative VO2peak were significantly associated with changes in a non-linear HRV measure, α1 (p<0.01), independent of age and eGFR (r2=0.196, p=0.03). Despite the significant increase in cardiorespiratory fitness for the LI group, there were no changes in cardiac autonomic function. However, α1 may be a sensitive measure to assess VO2peak changes in this clinical cohort. Further research is required to investigate the role of different modalities of exercise training to enhance cardiac autonomic function in patients with CKD.

P3751The reinnrevation with pulmonary vein isolation associated cardiac autonomic dysfunction

Abstract Background It is well-known that cardiac autonomic nerve is impaired after Pulmonary vein isolation (PVI) for atrial fibrillation (Af), but the the long-term change in cardiac autonomic function is unclear. Objective We followed the long-term cardiac autonomic nervous function after PVI and clarified its recoverability. Subjects Of 136 patients who received 1st session PVI from 2013 to 2017, 49 patients [Male: 86%, 62±11y, Diabetes meritus: 16%, radiofrequency (RF) ablation: 59%, cryoballoontechnique (Cryo): 41%, left atrial diameter: 37.2±4.5mm, LVEF: 67.4±9.7%, BNP: 103±108pg/dl]who satisfied the Inclusion criteria (No history of cardiac surgery, no recurrence of Afafter PVI for more than 1 year, with Holter ECG record of sinus rhythm before PVI and every 3 months after PVI for 1 year or more. Method Heart rate variability (HRV) parameters for each period (before PVI and after PVI 0–3 months, 3–6 months, 6–9 months, 9–12 months) were obtained from each Holter ECG records using MemCalcsystem. We defined the HRV before PVI as 100% and examined the rate of change for each HRV (see Figure) after PVI retrospectively. Result All of HRV indicators after PVI had been decreased significantly at 0–3 months after PVI (from 21.7% to maximum of 77.9% down). Figure is a series of indexes from front to back in order of decreasing HRV at 0–3 months after PVI, and the frequency domain index concentrates on the front. These decreased HRVs gradually recovered through 12 months after PVI (shown in figure left), but this change is more responsive in the frequency domain index than in the time-domain index, and after 3–6 months, all indices has already showed a significant rise compared with 0–3 months after PVI. In any of the indices, this increase over time did not receive interaction due to the difference in the procedure (RF, Cryo). Conclusion HRV decreased by PVI showed a significant rise over time, mainly in the frequency domain, at 3–6th month after PVI, suggesting the existence of reinnervation of cardiac autonomic nerve at this period.

&lt;b&gt;Cardiac autonomic profile in cervical spinal cord injury subjects practitioners of the physical exercise

The aim was investigate the time-course of cardiac autonomic response in men with incomplete cervical spinal cord injury (SCI) practitioners or not of physical exercise. Twenty men were separated into three groups: control group without SCI (CON; 28.3 ± 4.5 yrs; 178.4 ± 6.5 cm; 82.1 ± 6.8 kg; n=8), regularly engaged in strength training and low aerobic training; exercise group with cervical SCI (EG, 32.3 ± 4.5 yrs, 175.1 ± 5.3 cm, 73.6 ± 9.6 Kg; n=8) that practiced wheelchair rugby and sedentary group with cervical SCI (SG, 30.8 ± 5.3 yrs, 173.4 ± 10.1 cm, 69.7 ± 7.1 Kg; n=4) who did not practice physical exercise. Heart rate variability variables were calculated from ECG, in rest. CON showed high values compared to EG and SG of: standard deviation of R-R intervals (SDNN), proportion of adjacent R-R intervals differing by more than 50 ms, number of interval differences of successive NN intervals greater than 50 ms, root mean square of successive differences and the high-frequency spectral power. SDNN was significantly lower in EG compared to CON. changes in cardiac autonomic function could be noted in subjects with cervical SCI regularly engaged in an exercise program.

Adiponectin, biomarkers of inflammation and changes in cardiac autonomic function: Whitehall II study

BackgroundBiomarkers of inflammation and adiponectin are associated with cardiovascular autonomic neuropathy (CAN) in cross-sectional studies, but prospective data are scarce. This study aimed to assess the associations of biomarkers of subclinical inflammation and adiponectin with subsequent changes in heart rate (HR) and heart rate variability (HRV) in non-diabetic and diabetic individuals.MethodsData are based on up to 25,050 person-examinations for 8469 study participants of the Whitehall II cohort study. Measures of CAN included HR and several HRV indices. Associations between baseline serum levels of high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-6, IL-1 receptor antagonist (IL-1Ra) and adiponectin and 5-year changes in HR and six HRV indices were estimated using mixed-effects models adjusting for age, sex, ethnicity, body mass index (BMI), metabolic covariates and medication. A modifying effect of diabetes was tested.ResultsHigher levels of IL-1Ra were associated with higher increases in HR. Additional associations with measures of HRV were observed for hsCRP, IL-6 and IL-1Ra, but these associations were explained by BMI and other confounders. Associations between adiponectin, HR and HRV differed depending on diabetes status. Higher adiponectin levels were associated with more pronounced decreases in HR and increases in three measures of HRV reflecting both sympathetic and vagal activity, but these findings were limited to individuals with type 2 diabetes.ConclusionsHigher IL-1Ra levels appeared as novel risk marker for increases in HR. Higher adiponectin levels were associated with a more favourable development of cardiovascular autonomic function in individuals with type 2 diabetes independently of multiple confounders.

Cardiac Autonomic Regulation and Repolarization During Acute Experimental Hypoglycemia in Type 2 Diabetes.

Hypoglycemia is associated with increased cardiovascular mortality in trials of intensive therapy in type 2 diabetes mellitus (T2DM). We previously observed an increase in arrhythmias during spontaneous prolonged hypoglycemia in patients with T2DM. We examined changes in cardiac autonomic function and repolarization during sustained experimental hypoglycemia. Twelve adults with T2DM and 11 age- and BMI-matched control participants without diabetes underwent paired hyperinsulinemic clamps separated by 4 weeks. Glucose was maintained at euglycemia (6.0 mmol/L) or hypoglycemia (2.5 mmol/L) for 1 h. Heart rate, blood pressure, and heart rate variability were assessed every 30 min and corrected QT intervals and T-wave morphology every 60 min. Heart rate initially increased in participants with T2DM but then fell toward baseline despite maintained hypoglycemia at 1 h accompanied by reactivation of vagal tone. In control participants, vagal tone remained depressed during sustained hypoglycemia. Participants with T2DM exhibited greater heterogeneity of repolarization during hypoglycemia as demonstrated by T-wave symmetry and principal component analysis ratio compared with control participants. Epinephrine levels during hypoglycemia were similar between groups. Cardiac autonomic regulation during hypoglycemia appears to be time dependent. Individuals with T2DM demonstrate greater repolarization abnormalities for a given hypoglycemic stimulus despite comparable sympathoadrenal responses. These mechanisms could contribute to arrhythmias during clinical hypoglycemic episodes.

Relationship between inflammatory and coagulation biomarkers and cardiac autonomic function in HIV-infected individuals.

To examine the relationship between inflammatory and coagulation biomarkers and cardiac autonomic function (CAF) as measured by heart rate variability in persons with HIV. This analysis included 4073 HIV-infected persons from the Strategies for Management of Antiretroviral Therapy study. We examined the association between IL-6, high-sensitivity C-reactive protein (hsCRP) and D-dimer with heart rate variability measures (SDNN and rMSSD), both cross-sectionally and longitudinally. Cross-sectional analysis revealed significant inverse associations between IL-6, hsCRP and d-dimer with SDNN and rMSSD (p < 0.01 for all comparisons). However, longitudinal analysis failed to show a significant association between baseline IL-6, hsCRP and d-dimer with change in CAF over time. Cross-sectionally, higher levels of inflammatory and coagulation biomarkers were associated with lower levels of CAF in the Strategies for Management of Antiretroviral Therapy trial. Although deterioration in CAF was observed during followup, baseline levels of inflammatory and coagulation markers were not predictive of the decline in CAF over time.

Comparison of particulate matter dose and acute heart rate variability response in cyclists, pedestrians, bus and train passengers

Exposure to airborne particulate matter (PM) has been linked to cardiovascular morbidity and mortality. Heart rate variability (HRV) is a measure of the change in cardiac autonomic function, and consistent links between PM exposure and decreased HRV have been documented in studies. This study quantitatively assesses the acute relative variation of HRV with predicted PM dose in the lungs of commuters. Personal PM exposure, HR and HRV were monitored in 32 young healthy cyclists, pedestrians, bus and train passengers. Inhaled and lung deposited PM doses were determined using a numerical model of the human respiratory tract which accounted for varying ventilation rates between subjects and during commutes. Linear mixed models were used to examine air pollution dose and HRV response relationships in 122 commutes sampled. Elevated PM2.5 and PM10 inhaled and lung deposited doses were significantly (p<0.05) associated with decreased HRV indices. Percent declines in SDNN (standard deviation of normal RR intervals) relative to resting, due to an inter-quartile range increase in PM10 lung deposited dose were stronger in cyclists (−6.4%, 95% CI: −11.7, −1.3) and pedestrians (−5.8%, 95% CI: −11.3, −0.5), in comparison to bus (−3.2%, 95% CI: −6.4, −0.1) and train (−1.8%, −7.5, 3.8) passengers. A similar trend was observed in the case of PM2.5 lung deposited dose and results for rMSSD (the square root of the squared differences of successive normal RR intervals) followed similar trends to SDNN. Inhaled and lung deposited doses accounting for varying ventilation rates between modes, individuals and during commutes have been neglected in other studies relating PM to HRV. The findings here indicate that exercise whilst commuting has an influence on inhaled PM and PM lung deposited dose, and these were significantly associated with acute declines in HRV, especially in pedestrians and cyclists.

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.

Atrial Fibrillation Associated With Epileptic Seizures—Reply

Background Epileptic seizures are often associated with changes in cardiac autonomic function. Yet atrial fibrillation (AFib) or atrial flutter (AFlu) following epileptic seizures has only rarely been reported in the past. Objectives To describe and characterize patients who experienced lone AFib or AFlu as a consequence of epileptic seizures. Design Case reports. Setting University teaching hospital. Patients We describe 4 patients who developed transient AFib following epileptic seizures and 1 patient who developed transient AFlu following epileptic seizures. Results In all patients, AFib and AFlu followed a generalized tonic-clonic seizure. The arrhythmia usually lasted a few hours and converted spontaneously to a normal sinus rhythm. In 3 patients, AFib or AFlu developed during the first seizure they experienced, and none of the patients developed drug-resistant epilepsy. Moreover, none of the patients had a known cardiac disease, yet, in 2 patients, the cardiological workup demonstrated mild abnormalities on the cardiac stress test. Conclusions Atrial fibrillation is the most common type of arrhythmia, with an estimated prevalence of 1%. Despite the fact that AFib can cause syncope, it is important to consider the possibility of AFib developing secondary to an epileptic seizure in cases of AFib and transient loss of consciousness.

Atrial Fibrillation Associated With Epileptic Seizures

Epileptic seizures are often associated with changes in cardiac autonomic function. Yet atrial fibrillation (AFib) or atrial flutter (AFlu) following epileptic seizures has only rarely been reported in the past. To describe and characterize patients who experienced lone AFib or AFlu as a consequence of epileptic seizures. Case reports. University teaching hospital. We describe 4 patients who developed transient AFib following epileptic seizures and 1 patient who developed transient AFlu following epileptic seizures. In all patients, AFib and AFlu followed a generalized tonic-clonic seizure. The arrhythmia usually lasted a few hours and converted spontaneously to a normal sinus rhythm. In 3 patients, AFib or AFlu developed during the first seizure they experienced, and none of the patients developed drug-resistant epilepsy. Moreover, none of the patients had a known cardiac disease, yet, in 2 patients, the cardiological workup demonstrated mild abnormalities on the cardiac stress test. Atrial fibrillation is the most common type of arrhythmia, with an estimated prevalence of 1%. Despite the fact that AFib can cause syncope, it is important to consider the possibility of AFib developing secondary to an epileptic seizure in cases of AFib and transient loss of consciousness.

Cardiac autonomic modulation during methadone therapy among heroin users: A pilot study

Methadone therapy benefits heroin users in both the medical and psychosocial dimensions. However, both heroin and methadone have cardiac toxicity. Only limited information is available describing the changes in cardiac autonomic function of heroin users and effects of methadone therapy. We conduct the current study to explore the cardiac vagal function in heroin users as well as the impact of lapse and methadone therapy. 80 heroin users from a methadone therapy clinic were distributed into 31 compliant and 49 incompliant patients according to whether they lapsed into heroin use within 10 days. 40 healthy control subjects were recruited from the community. Participants underwent electrocardiographic recordings and the heroin users were further investigated before and after methadone therapy. Spectral analysis of heart rate variability (HRV) was computed for cardiac parasympathetic modulation (high-frequency power, HF) and cardiac sympathetic modulation (normalized low-frequency power, LF%). The baseline HRV parameters found lower HF values for heroin users and lower RR interval values for patients with a recent lapse compared with the healthy control subjects. After 1h of methadone administration, heroin users who had lapsed showed a significant increase in HF but the heroin users who had not lapsed did not. Our findings suggest that heroin users show decreased cardiac vagal activity and that methadone therapy immediately facilitates vagal regulation in patients with a recent lapse. The differential patterns of autonomic alteration under methadone between those with and without lapse might offer an objective measure of lapse.

Heart rate variability changes at 2400 m altitude predicts acute mountain sickness on further ascent at 3000–4300 m altitudes

Objective: If the body fails to acclimatize at high altitude, acute mountain sickness (AMS) may result. For the early detection of AMS, changes in cardiac autonomic function measured by heart rate variability (HRV) may be more sensitive than clinical symptoms alone. The purpose of this study was to ascertain if the changes in HRV during ascent are related to AMS. Methods: We followed Lake Louise Score (LLS), arterial oxygen saturation at rest (R-SpO2) and exercise (Ex-SpO2) and HRV parameters daily in 36 different healthy climbers ascending from 2400 m to 6300 m altitudes during five different expeditions. Results: After an ascent to 2400 m, root mean square successive differences, high-frequency power (HF2 min) of HRV were 17–51% and Ex-SpO2 was 3% lower in those climbers who suffered from AMS at 3000 to 4300 m than in those only developing AMS later (≥5000 m) or not at all (all p < 0.01). At the altitude of 2400 m RMSSD2 min ≤ 30 ms and Ex-SpO2 ≤ 91% both had 92% sensitivity for AMS if ascent continued without extra acclimatization days. Conclusions: Changes in supine HRV parameters at 2400 m were related to AMS at 3000–4300 m Thus, analyses of HRV could offer potential markers for identifying the climbers at risk for AMS.

Cardiac autonomic function reveals adaptation to military training

The last 4 weeks of basic military training are very stressful. We tested the hypothesis that changes in cardiac autonomic function during this period are associated with changes in maximal oxygen uptake and/or serum hormonal concentrations in male conscripts (n=22). Cardiac vagal autonomic function was assessed by measuring the high-frequency (0.15–0.4 Hz) spectral power of R–R intervals. Maximal oxygen uptake ([Vdot]O2max) and basal serum testosterone concentration were measured at the beginning and end of the period. Individual changes in vagally mediated high-frequency power (range −15% to +25%) correlated (r=0.73, P=0.001) with changes in [Vdot]O2max (range −9% to +6%) and changes in testosterone concentration (range −52% to +43%; r=0.43, P=0.047). The mean values of [Vdot]O2max and testosterone concentration did not change during the study period. Measurements of autonomic function could be a useful tool for indicating adaptation to the highly stressful conditions associated with basic military training.

Multi-flavanoid Supplementation Alone Has No Effect On Resting Cardiac Autonomic Modulation In Young Pre-Hypertensive Individuals

Antioxidant supplementation has been shown to induce positive benefits on cardiovascular health including reductions in blood pressure (BP) mediated by decreases in reactive oxygen species. The autonomic nervous system plays a role in regulating blood pressure via changes in vagal tone. PURPOSE: To examine the effects of a unique multi-flavanoid supplement on cardiac autonomic modulation in pre-hypertensive, college-aged individuals. METHODS: 20 Pre-hypertensive college students were randomly assigned to either a placebo (Pla, 21.6±0.6 years n=10) or treatment group (trt, 20.7±0.3 years, n=10). The antioxidant supplement included 1000 mg quercetin, 120 mg epigallocatechin 3-gallate (EGCG), 400 mg isoquercetin, and 400 mg omega-3 fatty acids. The subjects were asked to report to the lab for baseline measurements then prior to, and following 2 weeks of either Pla or trt supplementation. Beat to beat blood pressure was measured with their left arm while a 3-lead EKG (modified CM5) recorded low frequency (LF), high frequency (HF) and total power (TP) for 10 minutes during supine rest in a dimly lit room. RESULTS: There was a small but statistically insignificant (NSD) decrease in mean arterial pressure in the trt group with no change in the Pla group (Pla 88.7 ± 4 to 90.3 ± 4 mmHg vs. trt group 91 ± 5 to 88.9 ± 5 mmHg respectively, p=0.08), however no changes in cardiac autonomic modulation (NSD in LF:HF, TP or normalized data) in either the Pla or trt groups was found. CONCLUSION: The multiflavanoid supplement did not significantly decrease blood pressure and showed no changes in cardiac autonomic function when compared to the placebo group. While MAP was not statistically significant, small decreases in MAP may result in significant physiological reductions in cardiovascular risk factors. Supported by grant from BeActive/Appalachian Partnership (Scott Collier, PI).

Autonomic function following endoscopic thoracic sympathotomy for hyperhidrosis

Primary palmar-plantar hyperhidrosis is the condition of excessive sweating of the hands and feet. For severe and medically refractory cases, endoscopic thoracic sympathotomy (ETS) is a bilateral ganglion-sparing disconnection between the stellate and T2 ganglion in an effort to minimize compensatory hyperhidrosis. The purpose of this study was to determine the effect of ETS on cardiac autonomic function. Participants in this study were 22 otherwise healthy hyperhidrosis patients with 17 returning 1-12months after surgery. Heart rate (HR) and blood pressure were collected at rest and during sequential nitroprusside/phenylephrine infusion (modified Oxford). To determine change in cardiac autonomic function, heart rate variability indices of RMSSD, LF and HF (log, nu) power were calculated. Sequential baroreflex sensitivity was also calculated. After surgery, resting HR on standardized ECG tended to be lower and reached significance during the modified Oxford baseline (p<0.001). HRV changed significantly between assessments with an increase in HF (nu) and decrease in LF (nu) and LF (log) spectral ranges (p<0.05), while the increase in RMSSD was marginally significant (p<0.06). Compared with matched controls, HRV indices were significantly different before surgery, but similar after surgery. No change was detected in resting sequential baroreflex sensitivity, baroslope obtained by modified Oxford or QTc interval. We conclude that ETS changes cardiac autonomic modulation of HR to levels similar to controls. Despite the minimally destructive nature of ETS, effects on HRV are consistent with previously reported post-sympathectomy blunting of exaggerated sympathetic control associated with hyperhidrosis. No significant changes in the baroreflex indices suggest that ETS did not significantly affect blood pressure regulation.

Transcranial magnetic stimulation for auditory hallucination in severe schizophrenia: Partial efficacy and acute elevation of sympathetic modulation

Repetitive transcranial magnetic stimulation (rTMS) has been reported to be an effective treatment for auditory hallucination (AH) in schizophrenia patients. The efficacy of rTMS and immediate changes in cardiac autonomic function (CAF) after rTMS in severe schizophrenia patients with AH (n = 8) were investigated. Three patients reported a >or=50% reduction of AH after rTMS. The ratio of low-frequency power to high-frequency power, an index of sympathetic modulation, increased significantly after rTMS. Further replication studies with larger sample sizes are indicated.

Effect of pioglitazone on systemic inflammation is independent of metabolic control and cardiac autonomic function in patients with type 2 diabetes

The aim of this article is to investigate the relation of the anti-inflammatory effect of pioglitazone with cardiac autonomic function and metabolic control in diabetic patients. In this prospective open label trial, 36 type 2 diabetic patients (age 60 ± 10, 20 M) without overt cardiovascular disease were randomized to add pioglitazone (30 mg) to their therapy or to continue standard therapy. C-reactive protein (CRP) serum levels, metabolic parameters and cardiac autonomic function (assessed by heart rate variability [HRV] on 24-h ECG Holter monitoring) were measured at baseline and after 3 months. Clinical and laboratory variables were similar in the two groups. No significant changes were observed after 3 months for metabolic and anthropometric parameters, except for a mild increase in HDL levels in the pioglitazone group only (P = 0.04 vs. controls). CRP levels decreased significantly at follow-up in the pioglitazone group (3.2 ± 1.97 vs. 2.37 ± 1.56 mg/l) but not in the control group (3.0 ± 1.92 vs. 3.93 ± 2.14 mg/l; P = 0.003). No differences were found in basal and follow-up HRV variables between the two groups. In type 2 diabetic patients pioglitazone exerts favourable effects on inflammation even after short-term therapy. This effect precedes those on metabolic and anthropometric parameters and is not associated with changes in cardiac autonomic function.

Exposure to environmental carbon monoxide may have a greater negative effect on cardiac autonomic function in people with metabolic syndrome

Carbon monoxide (CO) has been recognized as a risk factor for adverse cardiovascular outcomes. We investigated the effects of CO on cardiac autonomic function by measuring the heart rate variability (HRV) in patients with and without metabolic syndrome (MetS). We also explored the relationship between CO exposure and specific components of MetS. Data were obtained from air pollution measurements and from health examinations on a total of 986 subjects, from a Korean community. Measurements of the 5-min HRV and examinations for MetS were conducted, and a linear regression model with a time lag was evaluated for any association. The group with MetS showed a significant reduction in the standard deviation of the normal-to-normal intervals (SDNN) and in the high frequency domain of HRV. After adjusting for age, sex, smoking status, day of the week effect, month effect, temperature, and relative humidity, these declines were significantly associated with exposure to CO for 25 to 48 h prior to the HRV measurement. Evidence for effect-modification by two specific MetS components, fasting blood glucose and triglycerides, was also observed in relation to CO exposure. These results suggest that CO exposure may trigger changes in cardiac autonomic function, and that subjects at high risk for heart disease may be more susceptible to CO effects.