Cardiac Autonomic Function In Patients Research Articles

Baroreflex activation therapy in patients with heart failure and a reduced ejection fraction: Long-term outcomes.

Carotid baroreflex activation therapy (BAT) restores baroreflex sensitivity and modulates the imbalance in cardiac autonomic function in patients with heart failure with reduced ejection fraction (HFrEF). We tested the hypothesis that treatment with BAT significantly reduces cardiovascular mortality and heart failure morbidity and provides long-term safety and sustainable symptomatic improvement. BeAT-HF was a prospective, multicentre, randomized, two-arm, parallel-group, open-label, non-implanted control trial. New York Heart Association (NYHA) class III subjects, ejection fraction ≤35%, previous heart failure hospitalization or N-terminal pro-B-type natriuretic peptide (NT-proBNP) >400 pg/ml, no class I indication for cardiac resynchronization therapy and NT-proBNP <1600 pg/ml were randomized to BAT plus optimal medical management (BAT group) or optimal medical management alone (control). The primary endpoint was cardiovascular mortality and HF morbidity; additional pre-specified endpoints included durability of safety, quality of life (QOL), exercise capacity (6-min hall walk distance [6MHWD]), functional status (NYHA class), hierarchical composite win ratio, freedom from all-cause death, left ventricular assists device (LVAD) implantation, heart transplant. Overall, 323 patients had 332 primary events, median follow-up was 3.6 years/patient. Both primary endpoint (rate ratio 0.94, 95% confidence interval [CI] 0.57-1.57; p = 0.82) and components of the primary endpoints were not significantly different between BAT and control. The system- and procedure-related major adverse neurological and cardiovascular event-free rate remained 97% throughout the trial. Symptom improvement (QOL, 6MHWD, NYHA class, all nominal p < 0.001) in the BAT group was durable in time, sustainable in extent. Win ratio (1.26, 95% CI 1.02-1.58) and freedom from all-cause death, LVAD implantation, heart transplant (hazard ratio 0.66, 95% CI 0.43-1.01) favoured the BAT group but did not reach statistical significance. The BeAT-HF primary endpoint was neutral; however, BAT provided safe, effective, and sustainable improvements in HFrEF patient's functional status, 6MHWD and QOL.

Relationship between dust allergen sensitization and cardiac autonomic function in patients with chronic obstructive pulmonary disease.

Cardiac autonomic function predicts cardiovascular disease risk. The aim of this study was to investigate the relationship between sensitization to dust allergens and cardiac autonomic dysfunction in patients with chronic obstructive pulmonary disease (COPD), and to provide new ideas for the prevention of cardiovascular complications in these patients. Immunoassays for sensitization to cats/dogs, cockroaches and dust mites were performed in 840 patients with COPD. Indicators of heart rate variability in these patients were used to assess cardiac autonomic function, including standard deviation of normal-to-normal intervals (SDNN), root-mean square of successive differences between normal-to-normal intervals (RMSSD), low-frequency power (LF), high-frequency power (HF), and LF/HF ratios, which were obtained based on ambulatory electrocardiographic monitoring data. The relationship between sensitization to these dust allergens and heart rate variability was explored using multivariate logistic regression. The multivariate analyses showed that sensitization to total allergens was associated with reduced levels of SDNN, RMSSD, LF and HF and with increased levels of the LF/HF ratio in the patients with COPD (p < .05). Dust allergen sensitization may be associated with cardiac autonomic dysfunction in patients with COPD. Whether desensitization can prevent cardiovascular complications in these patients should be further explored.

Effect of mandibular advancement splint therapy on cardiac autonomic function in obstructive sleep apnoea.

This study aimed to evaluate the effect of mandibular advancement splint (MAS) therapy on cardiac autonomic function in patients with obstructive sleep apnoea (OSA) using heart rate variability (HRV) analysis. Electrocardiograms (ECG) derived from polysomnograms (PSG) of three prospective studies were used to study HRV of patients with OSA before and after MAS treatment. HRV parameters were averaged across the entire ECG signal during N2 sleep using 2-min epochs shifted by 30s. Paired t-tests were used to compare PSG and HRV measures before and after treatment, and the percent change in HRV measures was regressed on the percent change in apnoea-hypopnea index (AHI). In 101 patients with OSA, 72% were Caucasian, 54% men, the mean age was 56±11 years, BMI 29.8±5.3 kg/m2, and treatment duration was 4.0±3.2 months. After MAS therapy, there was a significant reduction in OSA severity (AHI, - 18 ± 16 events per hour, p < 0.001) and trends towards increased low-frequency to high-frequency ratio, low-frequency power, and reduced high-frequency power (LF:HF, - 0.4 ± 1.5, p = 0.01; LF, - 3 ± 16 nu, p = 0.02, HF, 3.5 ± 13.7 nu, p = 0.01). Change in NN intervals correlated with the change in AHI (β(SE) = - 2.21 (0.01), t = - 2.85, p = 0.005). No significant changes were observed in the time-domain HRV markers with MAS treatment. The study findings suggestthat successful MAS treatment correlates with changes in HRV, specifically the lengthening of NN intervals, a marker for improved cardiac autonomic adaptability.

Analysis of CACNA1C and KCNH2 Risk Variants on Cardiac Autonomic Function in Patients with Schizophrenia.

Cardiac autonomic dysfunction (CADF) is a major contributor to increased cardiac mortality in schizophrenia patients. The aberrant function of voltage-gated ion channels, which are widely distributed in the brain and heart, may link schizophrenia and CADF. In search of channel-encoding genes that are associated with both CADF and schizophrenia, CACNA1C and KCNH2 are promising candidates. In this study, we tested for associations between genetic findings in both genes and CADF parameters in schizophrenia patients whose heart functions were not influenced by psychopharmaceuticals. First, we searched the literature for single-nucleotide polymorphisms (SNPs) in CACNA1C and KCNH2 that showed genome-wide significant association with schizophrenia. Subsequently, we looked for such robust associations with CADF traits at these loci. A total of 5 CACNA1C SNPs and 9 KCNH2 SNPs were found and genotyped in 77 unmedicated schizophrenia patients and 144 healthy controls. Genotype-related impacts on heart rate (HR) dynamics and QT variability indices (QTvi) were analyzed separately in patients and healthy controls. We observed significantly increased QTvi in unmedicated patients with CADF-associated risk in CACNA1C rs2283274 C and schizophrenia-associated risk in rs2239061 G compared to the non-risk allele in these patients. Moreover, unmedicated patients with previously identified schizophrenia risk alleles in KCNH2 rs11763131 A, rs3807373 A, rs3800779 C, rs748693 G, and 1036145 T showed increased mean HR and QTvi as compared to non-risk alleles. We propose a potential pleiotropic role for common variation in CACNA1C and KCNH2 associated with CADF in schizophrenia patients, independent of antipsychotic medication, that predisposes them to cardiac arrhythmias and premature death.

Investigation of the Cardiac Autonomic Functions in Patients with Essential Tremor

Introduction: Essential tremor is a neurological disorder that causes involuntary shaking. The aim of this study was to examine cardiac autonomic functions in patients diagnosed with essential tremor, as previous studies have differed in their findings regarding whether cardiac autonomic functions are affected in essential tremor patients. Patients and Methods: The study included 32 patients diagnosed with essential tremor and 26 individuals without any diseases as the control group. Consensus criteria were used for the diagnosis of essential tremor. A clinical rating scale was utilized to measure the characteristics and degree of essential tremor. Based on this scale, patients were classified as having a mild, moderate, marked, or severe disability. An exercise treadmill test was performed in both the tremor and control groups. Chronotropic index values were used to evaluate the sympathetic system, and resting heart rate index values were calculated to evaluate the parasympathetic system. Heart rate recovery values were calculated at one, two, three, four, and five minutes after the exercise treadmill test. Results: The descriptive characteristics of the tremor and control groups were similar. The Chronotropic index values were statistically different between the tremor and control groups, as they were significantly decreased in the tremor group. This was evaluated as sympathetic incompetence. The resting heart rate index values did not differ significantly between the tremor and control groups at minutes one or two, but they were significantly higher in the tremor group at minutes three, four, and five. The parasympathetic activity was found to be insufficient in the later period. Conclusion: The findings suggest that cardiac autonomic functions may be affected in patients with essential tremor.

Comprehensive evaluation of patterns of hypoglycemia unawareness (HUA) and glycemic variability (GV) in patients with fibrocalculous pancreatic diabetes (FCPD): A cross-sectional study from South India.

Hypoglycemia unawareness (HUA) in patients with FCPD is common with an unclear etiology. We evaluated the prevalence, characteristics of HUA, glycemic variability (GV), its possible association with pancreatic glucagon secretion & cardiac autonomic function in patients with FCPD. A two-week ambulatory glucose profile (AGP) and cardiac autonomic function test was done in patients with FCPD (n = 60), and categorized into UNAWARE (n = 44) and AWARE (n = 16) groups based on the Hypoglycemia Unawareness Index (HUI) score. Glycaemic variability was assessed from the AGP data using Easy GV 9.0.2 software. A subset of patients from both the groups (n = 11) underwent a mixed-meal challenge test and were compared with healthy individuals (controls; n = 11). HUA was evidenced in 73% (44/60) of patients with FCPD. Significant hypoglycemia, nocturnal hypoglycemia, duration of hypoglycemia and poor cardiac autonomic functions (p = 0.01) were prominent in the UNAWARE group. The overall GV was greater in the UNAWARE group. In the UNAWARE group, significantly reduced fasting and post prandial glucagon levels negatively correlated with HUI (r = -0.74, p < 0.05) and GV-hypoglycemia indices (p < 0.05) In contrast, significantly higher post prandial glucagon levels in the AWARE group positively correlated with post prandial hyperglycemia (r = 0.61, p < 0.05). Heterogeneity in patterns of glucagon secretion were significantly associated with HUA and GV. Reduced glucagon levels contribute to greater risks of HUA, nocturnal hypoglycemia and greater GV, while hyperglucagonemia predisposes to postprandial hyperglycemia and hypoglycemia awareness in patients with FCPD.

A study of cardiac autonomic functions in patients with chronic migraine versus chronic Tension-type Headache (TTH) in adults cardiac autonomic functions in headache

Objective: To assess cardiac autonomic functions in patients with chronic migraine and chronic tension-type headache (TTH) in adults using heart rate variability (HRV). Methods: Two groups of patients having chronic migraine (n = 25) and chronic TTH (n = 25) were enrolled for this study. HRV was analyzed with the help of BIOPAC MP150. Statistical analysis was performed with SPSS version 21. Unpaired t-test and Mann-Whitney test were used for parameters with normal and nonnormal distribution, respectively. Results: In chronic migraine group, SDNN (38.90 ± 22.14 vs 41.71 ± 20.81 ms, p=1.000), RMSSD (39.20 ± 25.14 vs 64.11 ± 156.74 ms, p=0.437) and pNN50 (13.37 ± 17.94 vs 18.56 ± 20.42, p=0.496) were lower than in chronic THH group. Frequency domain parameters like LF (614.20 ± 604.89 ms2 vs 595.81 ± 597.08 ms2, p=0.823) and HF (1190.68 ± 1330.87 ms vs 832.52 ± 1356.70 ms2, p=0.148 were higher for chronic THH group compared to chronic migraine group. The total power for chronic THH group was higher compared to chronic migraine group (2447.93 ± 2215.03 ms2 vs 1845.27 ± 1550.38 ms2, p=0.308).

Evaluation of cardiovascular autonomic function in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a type of inflammatory arthritis that affects people all over the world. RA is a chronic systemic inflammatory autoimmune disease. It primarily affects the joints and is frequently accompanied by extra-articular symptoms such as rheumatoid nodules, neuropathy, and normochromic normocytic anaemia. Objectives- The aim of this study was to evaluate cardiac autonomic function in patients with rheumatoid arthritis and compare with healthy individuals. An observational, cross-sectional study was done between 50 having RA &amp; 50 normal healthy subjects not on any medication, on both males &amp; females between the age group of 30-60 years. Evaluation of autonomic nervous system was done with the help of non-invasive tests. Parasympathetic system was assessed by heart rate response to standing &amp; heart rate response to lying down position. Sympathetic system was assessed by blood pressure response to standing, BP response to Valsalva Maneuverer &amp; BP response to sustained hand grip. In individuals with Rheumatoid Arthritis, the diastolic blood pressure in standing position was significantly lower(p&amp;#60;0.01) than control group. Other parameters showed non- significant changes in RA group compared to control group. Discussion- study confirmed autonomic dysfunction occurs in patient with rheumatoid arthritis. Therefore, autonomic function may be the part of routine clinical examination in RA to reduce the cardiovascular autonomic morbidity Cardiovascular autonomic function tests in daily clinical examination helpful in early detection of autonomic dysfunction in rheumatoid arthritis.

High-Intensity Interval Training Improves Cardiac Autonomic Function in Patients with Type 2 Diabetes: A Randomized Controlled Trial.

Simple SummaryDiabetes mellitus is a metabolic disorder characterized by an increased blood glucose concentration. The most common diabetes is type 2, corresponding to approximately 95% of the diagnosed cases. Chronic hyperglycemia can lead to many complications such as increased incidence of cardiovascular diseases as well as renal and ophthalmologic complications. Physical exercise is seen as an effective non-pharmacological strategy for managing the disease. In the present study, 44 middle-aged adults with type 2 diabetes were recruited and stratified into three exercise groups: HIIT-30:30, HIIT-2:2, and MICT. All patients were submitted to anamnesis, evaluation of cardiorespiratory fitness, and cardiac autonomic modulation, and were submitted to physical exercise programs for eight weeks. From the results found, it was possible to infer that high intensity physical training programs can be safe and effective for patients with type 2 diabetes and might be performed in different phases of a rehabilitation program. However, it is necessary to know how to work with the prescription of these exercises considering its cost effectiveness, because, in this study, the protocols HIIT-2:2 and HIIT-30:30 presented superior benefits to the MICT protocol.Different exercise models have been used in patients with type 2 diabetes mellitus (T2D), like moderate intensity continuous training (MICT) and high intensity interval training (HIIT); however, their effects on autonomic modulation are unknown. The present study aimed to compare the effects of different exercise modes on autonomic modulation in patients with T2D. In total, 44 adults with >5 years of T2D diagnosis were recruited and stratified into three groups: HIIT-30:30 (n = 15, age 59.13 ± 5.57 years) that performed 20 repetitions of 30 s at 100% of VO2peak with passive recovery, HIIT-2:2 (n = 14, age 61.20 ± 2.88) that performed 5 repetitions of 2 min at 100% of VO2peak with passive recovery, and MICT (n = 15, age 58.50 ± 5.26) that performed 14 min of continuous exercise at 70% of VO2peak. All participants underwent anamnesis and evaluation of cardiorespiratory fitness and cardiac autonomic modulation. All protocols were equated by total distance and were performed two times per week for 8 weeks. Group × time interactions were observed for resting heart rate (HRrest) [F(2.82) = 3.641; p = 0.031] and SDNN [F(2.82) = 3.462; p = 0.036]. Only the HIIT-30:30 group significantly reduced SDNN (p = 0.002 and 0.025, respectively). HRrest reduced more in the HIIT-30:30 group compared with the MICT group (p = 0.038). Group × time interactions were also observed for offTAU [F(2.82) = 3.146; p = 0.048] and offTMR [F(2.82) = 4.424; p = 0.015]. The MICT group presented increased values of offTAU compared with the HIIT-30:30 and HIIT-2:2 groups (p = 0.001 and 0.013, respectively), representing a slower HR response after eight weeks of intervention. HIIT, specially HIIT-30:30, represents a promising measure for improving autonomic modulation in patients with T2D.

235 Ventricular arrhythmias and cardiac autonomic function in patients with severe aortic valve stenosis before and after transcatheter aortic valve implantation

Abstract Aims Transcatheter aortic valve implantation (TAVI) has become a first-line treatment for most patients with severe aortic stenosis (AS) at intermediate/high surgical risk, resulting in significant improvement of clinical outcome. However, whether ventricular arrhythmias (VAs) or cardiac autonomic dysfunction influence outcome and whether TAVI has any effects on VAs and cardiac autonomic function is unknown. Thus, this study was aimed to investigate: I1) whether VAs and autonomic dysfunction [as assessed by heart rate variability (HRV)] are associated with clinical outcome and (2) the effects of TAVI on VAs and HRV, in patients with severe AS. Methods and results We studied 71 consecutive patients with severe aortic stenosis, admitted to our department of Cardiovascular Medicine to undergo TAVI. Patients with previous cardiac surgery, percutaneous coronary revascularization, acute coronary syndrome, and other significant heart valve disease or relevant comorbidities were excluded. The day before TAVI all patients underwent transthoracic Doppler echocardiography (TTDE), including global longitudinal strain (GLS) assessment, and 24-h ECG Holter monitoring (HM), to assess VA burden and HRV. A clinical follow-up was performed at 6 months from discharge. Furthermore, TTDE and 24-h HM were performed at follow-up in 38 (54.5%) and 29 (40.8%) patients, respectively. The primary endpoint was the occurrence of major clinical events (MACE), that include death, hospitalization for cardiac causes, pacemaker implantation, myocardial infarction, or stroke. Of 71 patients (48 female, mean age 80.5 ± 6.5 years) enrolled in the study, a 6-month clinical follow-up could be performed in 54 (76%). MACE occurred in 21 patients (38.9%), 8 of whom (14.8%) had hospitalization for heart failure, 13 (24%) required pacemaker implantation, and 3 had stroke (5.6%). Compared to baseline, at follow-up the mean aortic valve gradient (50.6 ± 11.4 vs. 8.38 ± 3.23 mmHg, P &amp;lt; 0.001), left ventricle (LV) mass index (131.4 ± 38.9 vs. 112.9 ± 28.3 g, P = 0.007), pulmonary artery systolic pressure (37.3 ± 5.8 vs. 30.2 ± 9.8 mmHg; P &amp;lt; 0.001), and the ratio of Doppler transmitral early filling velocity to tissue-Doppler early diastolic mitral annular velocity (E/e′) (16 ± 5.3 vs. 13.2 ± 4.7 P &amp;lt; 0.001) were significantly reduced. In contrast no changes were observed in VAs. The number of premature ventricular complexes (PVCs) at HM was indeed 1062 ± 3833 vs. 1206 ± 3322 at follow-up and baseline, respectively (P = 0.11). Furthermore, PVCs &amp;gt;10 per hour were detected in a higher number of patients at 6-month follow-up, compared to baseline (23.8% vs. 45.2%; P = 0.022). No significant differences were detected in most time-domain and frequency-domain HRV parameters. Unexpectedly, SDNNi (62.8 ± 19.1 vs. 41.9 ± 16.5; P = 0.008), RMSSD (54.6 ± 36.6 vs. 30.1 ± 17.9; P = 0.024) and VLF (56.4 ± 49.6 vs. 29 ± 12.7; P = 0.028) were found to be significantly higher at follow-up compared to baseline. Conclusions Our data show that, in patients with severe AS, TAVI does not seem to have significant effects on VA burden, despite echocardiographic and clinical improvement. Similarly, our data failed to show significant improvement of sympatho-vagal balance at follow-up compared to baseline in these patients.

Assessment of cardiac autonomic function in patients with permanent and paroxysmal atrial fibrillation

Abstract Background Atrial fibrillation (AF) is the commonest abnormal heart rhythm with significant related morbidity and mortality. There is increasing evidence that abnormalities of the cardiac autonomic nervous system (ANS) are involved in the pathogenesis of AF. Exploring the ANS is possible through heart rate variability (HRV) evaluation. Purpose To investigate whether HRV is more abnormal in patients with permanent AF compared to paroxysmal AF. Design In a cross-sectional comparison, we studied two patient groups: permanent AF (n=30) and paroxysmal AF (n=31). Time-domain, frequency-domain and non-linear measures of HRV were determined using eMotion Faros ECG sensor. Participant's breathing was controlled with a metronome set at 12 breaths per minute. Data was analysed using SPSS software. Results Time-domain and non-linear indices of HRV were significant higher in permanent AF group compared to paroxysmal AF (table 1). Permanent AF was the only independent predictor of HRV on multivariable analysis in this cohort of patients (p=0.006) Conclusions First study investigating autonomic function in patients with permanent AF and paroxysmal AF. HRV indices were significantly higher in permanent AF compared to paroxysmal AF which may suggest pronounced cardiac autonomic influence in the pathophysiology of permanent AF. Funding Acknowledgement Type of funding sources: None.

Cardiac autonomic function in patients with early multiple sclerosis.

Cardiac autonomic dysfunction has been reported in patients with long-standing multiple sclerosis (MS); however, data in early disease are limited. The present study was aimed at evaluating cardiac autonomic function in patients with early MS in the context of white matter metabolic status, which could potentially affect functions of the autonomic brain centers. Cardiac sympathetic and baroreflex cardiovagal responses to the Valsalva maneuver, orthostatic test, and the Stroop test were evaluated in 16 early, treatment-naïve patients with relapsing-remitting MS, and in 14 healthy participants. Proton magnetic resonance spectroscopic imaging (MRSI) of the brain was performed in eight of these MS patients and in eight controls. Valsalva maneuver outcomes were comparable between patients and controls. At baseline, norepinephrine levels were lower (p = 0.027) in MS patients compared to controls. The patients had higher heart rate (p = 0.034) and lower stroke volume (p = 0.008), but similar blood pressure, cardiac output and norepinephrine increments from baseline to 2min of the orthostatic test compared to controls. MS patients and controls did not differ in responses to the Stroop test. MRSI showed lower total N-acetylaspartate/total creatine (p = 0.038) and higher myo-inositol/total creatine (p = 0.013) in MS lesions compared to non-lesional white matter. Our results show normal cardiac sympathetic and baroreflex cardiovagal function in MS patients with relapsing-remitting MS with lesions at the post-acute/early resolving stage. The study was registered at ClinicalTrials.gov under the Identifier: NCT03052595 and complies with the STROBE checklist for cohort, case-control, and cross-sectional studies.

Physical activity and cardiac autonomic dysfunction in patients with chronic obstructive pulmonary disease: A cross-sectional analysis.

The cardiac autonomic function in patients with chronic obstructive pulmonary disease (COPD) has been poorly studied. We aimed to 1) describe the cardiac autonomic function assessed by heart rate recovery (HRR) and chronotropic response (CR) during a 6-min walk test (6MWT) and afterward and 2) estimate the association of physical activity with HRR and CR in COPD patients. This cross-sectional analysis included 320 patients with mild to very severe COPD. Physical activity (steps, time in any/moderate-to-vigorous/vigorous physical activity, intensity and sedentary time) was measured during 1 week by accelerometer. CR and HRR were measured during a 6MWT and 5min after, respectively, and their association with physical activity parameters was estimated by multivariable linear regression models. Patients were 82% male and had a mean (SD) age 68 (8) years, post-bronchodilator FEV1 57 (18) % predicted, and walked a mean of 7716 (4139) steps/day. HRR was slow until 5min after the 6MWT; the mean (SD) HRR was 15 (10), 22 (11), 25 (12), 25 (12) and 27 (12) bpm after 1, 2, 3, 4 and 5min, respectively. The mean (SD) CR was 35% (16). After adjusting for relevant confounders, time in vigorous physical activity was significantly associated with a fast decrease in HRR (p=0.044) and an increase in CR (p=0.021). We found no independent association for other physical activity parameters. A cardiac autonomic dysfunction is present in patients with mild to very severe COPD and is inversely related to the practice of vigorous physical activity. Trial registration ClinicalTrials.gov NCT01897298.

A Study of Cardiac Autonomic Functions in Patients with Chronic Stable Angina Undergoing Percutaneous Coronary Revascularization.

ObjectiveIn the present study, cardiac autonomic functions in CSA patients were evaluated before and after percutaneous coronary intervention (PCI) using heart rate variability (HRV).MethodsThirty patients with CSA were recruited from cardiology outpatient clinics of VMMC and Safdarjung hospital, New Delhi, India. For each patient HRV parameters (LF, HF, LF:HF ratio, SDNN, RMSSD, total power, and pNN50) were gathered before and after PCI. Data were compiled and analyzed using licensed statistical software: SPSS version 21.0.ResultsOut of 30 subjects, SDNN (61.47±22.27 vs. 32.24±16.50ms, p<0.0001), RMSSD (53.86±31.41 vs. 28.81±23.80ms, p=0.001) and pNN50 (46.24±34.36 vs. 5.20±6.63, p<0.0001) in post-PCI were significantly higher as compared to the pre-PCI values. There were significant increases in both LF (1193ms2±302.04ms2vs. 1054.60ms2±208 ms2, p<0.001) and HF (991.57±872.40ms2vs. 466.72ms2±257.93ms2, p<0.0001), also in total power (3548.37ms2±807.73ms2vs. 2428 ms2±867.07 ms2, p<0.0001) in post-PCI as compared to pre-PCI. The LF:HF ratio in pre-PCI was higher as compared to post-PCI (1.467±1.639 vs. 1.143±0.852, p=0.805), but the difference was not statistically significant.ConclusionIn this preliminary study, it is concluded that there is significant improvement in resting cardiovascular parameters, resting autonomic tone as measured by HRV which shows increase in both parasympathetic as well as sympathetic reactivity following revascularization by PCI in CSA patients. Hence, we also suggest that the use of noninvasive tests such as HRV should be done to stratify further risk of disease progression.

Association of heart rate variability with REM sleep without atonia in idiopathic REM sleep behavior disorder.

Idiopathic rapid eye movement sleep behavior disorder (iRBD), characterized by rapid eye movement sleep without atonia (RSWA) and dream-enactment behavior, has been suggested to be a predictor of α-synucleinopathies. Autonomic instability, represented by heart rate variability, is a common characteristic of both iRBD and α-synucleinopathies. Previous studies reported that RSWA was associated with autonomic dysfunction and was a possible predictor of phenoconversion. Therefore, we sought to compare heart rate variability between iRBD and control groups and explore the relationship between heart rate variability and RSWA in patients with iRBD. Nocturnal polysomnographic data on 47 patients (28 men, 19 women) diagnosed with iRBD based on video-polysomnography and 26 age-matched and sex-matched controls were reviewed. The first 5-minute epoch with a stable electrocardiogram lead II on video-polysomnography was selected from stage N2, wake, and rapid eye movement. For quantification of RSWA, tonic activity was analyzed from the submentalis electromyogram and phasic activity from the submentalis and bilateral anterior tibialis electromyogram channels. Compared to the control group, the iRBD group showed significant reductions in the standard deviation of the R-R intervals, the root mean square of successive R-R interval differences, and high-frequency values. Quantified tonic activity was inversely correlated with normalized low-frequency values and low-frequency/high-frequency ratios and positively correlated with normalized high-frequency values. This study implied decreased cardiac autonomic function in patients with iRBD, which showed parasympathetic predominance. Heart rate variability of the patients with iRBD in this study was associated with quantified tonic RSWA, which was previously reported to be a possible predictor of phenoconversion.

Obstructive sleep apnea syndrome and autonomic dysfunction in Duchenne muscular dystrophy.

Cardiac and respiratory involvement constitutes serious complications of Duchenne muscular dystrophy (DMD). We hypothesized that obstructive sleep apnea syndrome (OSAS) may play a role in cardiac autonomic dysfunction in DMD. We sought to assess the presence of cardiac autonomic function in patients with DMD by analyzing heart rate variability (HRV) during polysomnography (PSG). In a prospective study, all participants had whole-night PSG recorded and scored according to American Academy of Sleep Medicine guidelines. HRV analysis was performed on electrocardiography recordings from PSG recordings. Twelve consecutive males with DMD (mean age 9.0 ± 3.1 years, mean BMI 20.6 ± 4.8 kg/m2) and eight age-matched healthy males were enrolled. On clinical evaluation, 58% of patients with DMD had at least one symptom related to OSAS, such as snoring, witnessed apnea, or restless sleep. None of the controls had OSAS-related complaints. By PSG none of the controls had OSAS, while 42% of patients with DMD had OSAS (p = 0.004). Average R-R duration and mean percentage of successive R-R intervals > 50 ms values were significantly lower in patients with DMD than those in controls (p < 0.006). In patients with DMD and OSAS, LF/HF (low/high-frequency) ratio was significantly increased in NREM sleep compared with those in controls (p = 0.005). Higher apnea-hypopnea index and lower oxygen saturation showed significant correlations with higher LF power and LF/HF ratio (p < 0.001). Cardiac autonomic dysfunction is present in DMD, being more pronounced in the presence of OSAS.

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.

Acute Effects of Passion Fruit Juice Supplementation on Cardiac Autonomic Function and Blood Glucose in Healthy Subjects

Ascorbic acid supplementation provides beneficial effects on enhancing cardiac autonomic function in patients with heart failure. Ascorbic acid also reduces blood sugar levels and enhances insulin activity, and encourages cardiac autonomic function. Passion fruit is rich in ascorbic acid and potential antioxidants. This study aimed to evaluate the acute effects of passion fruit juice (PFJ) supplementation primarily on cardiac autonomic function and secondary on blood glucose in healthy subjects. A randomized cross-over trial was conducted in 14 healthy subjects aged 21.29±0.73 years. Subjects were supplemented with either 50% PFJ, or glucose and fructose solution as a placebo (PLA) at 3.5 mL/kg body mass with a 1-week washout between treatments in a single-dose design. Short-term heart rate variability and blood glucose levels were evaluated prior to supplementation (T0) and following supplementation for 30, 60, 90, and 120 min (T30, T60, T90, and T120, respectively). Indexes of cardiac autonomic function at T30, including high frequency power (P=0.03) and total power (P=0.01), were significantly higher and the ratio of low frequency/high frequency power was significantly lower (P=0.01) in the PFJ group compared to the PLA group. Blood glucose levels significantly increased at T30 in both PLA (P=0.00) and PFJ (P=0.00) groups. However, there were no significant differences between groups. A single administration of PFJ enhanced cardiac autonomic function through augmentation of parasympathetic activity, although it did not attenuate postprandial hyperglycemia. PFJ may be potentially recognized as beverage able to prevent cardiovascular disease.

Music therapy on non linear assessment of cardiac autonomic function in patients with major depressive disorder

Background :Non linear measure of heart rate variability (HRV) is an emerging method to detect changes in cardiac autonomic nerve function in major depressive disorder (MDD).&#x0D; Objective: To observe the effect of music therapy on non linear measures of HRV in newly diagnosed MDD patients.&#x0D; Methods: This prospective interventional study was done in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka in 2018 on 60 newly diagnosed MDD patients aged 20-40 years, both male and female. They were further subdivided into 30 patients with only antidepressant medication (Mirtazapine) and 30 patients received music therapy with Raga kafi (Rabindrasangeet) along with the same medication for 3 months. Age, sex and BMI matched healthy control were also enrolled. HRV non linear parameters were recorded by Power Lab 8/35. For statistical analysis paired sample ‘t’ test and independent sample ‘t’ test were done.&#x0D; Result: SD1, SD2 and SD1/SD2 were found significantly lower in MDD patients compared to healthy control at baseline. After 3 months of music therapy, significant increment of these parameters occurred with trend of improvement in cardiac autonomic nerve function (CANF) in these patients.&#x0D; Conclusion: This study concluded that music therapy can improve CANF by increasing parasympathetic and reducing sympathetic activity in MDD patients.&#x0D; J Bangladesh Soc Physiol. 2019, June; 14(1): 7-13

Effect of duration of hypertension on heart rate variability

Background: Hypertension is the most prevalent noncommunicable disease. It is a multisystem disorder that affects many organs of the body including cardiovascular system, and it markedly increases both morbidity and mortality in the population. Hypertension causes dysfunction of the cardiac autonomic nervous system leading to sympathovagal imbalance. Heart rate variability (HRV) is a non-invasive tool used to detect variation in RR intervals and has been proposed as early markers of vulnerability to ventricular arrhythmias. The present study was taken up to measure the effect of duration of the hypertension on HRV for early detection and early management of cardiac abnormalities. Aims and Objectives: The objectives of the study were to evaluate the effect of duration of the hypertension on cardiac autonomic function in patients with primary hypertension by measuring HRV. Materials and Methods: HRV test was performed on 50 male hypertensive patients who were divided into 2 groups, based on the duration of hypertension, i.e., duration of hypertension >5 years and 5 years duration (P 5 years, and it was highly significant. P < 0.001 showing decreased in parasympathetic activity in long-standing hypertension. Conclusion: Study showed reduced HRV parameters showing decreased parasympathetic activity in long-standing hypertension leading to an imbalance in cardiac autonomic function. It is very much important to evaluate the cardiac autonomic function status in long-standing hypertension using simple non-invasive tools for early detection and treatment of cardiac arrhythmias and other variations in cardiac function status.