Standard Deviation Of Normal-to-normal RR Intervals Research Articles

Suitability of Ultra-Short-Term Heart Rate Variability in Military Trainees.

We aimed to (a) evaluate the agreement between ultra-short-term and criterion resting heart rate variability (HRV) measures in military trainees, and (b) compare associations between HRV recording lengths and body composition. HRV recordings were performed for 10 min in 27 military male students. Mean RR interval, the root-mean square of successive differences (RMSSD), RMSSD:RR interval ratio, standard deviation of normal-to-normal RR intervals (SDNN), and SDNN:RR interval ratio were determined from the last 5 min of the 10-min recording and considered the criterion. Parameters were also recorded in successive 1-min epochs from the 5-min stabilization period. No differences were observed between criterion values and any of the 1-min epochs (p > 0.05). Effect sizes ranged from −0.36–0.35. Intra-class correlations ranged from 0.83–0.99. Limits of agreement ranged from 38.3–78.4 ms for RR interval, 18.8–30.0 ms for RMSSD, 1.9–3.1 for RMSSD:RR, 24.1–31.4 ms for SDNN, and 2.5–3.0 for SDNN:RR. Body fat% was associated (p < 0.05) with all HRV parameters at varying time segments. A 1-min HRV recording preceded by a 1-min stabilization period seems to be a suitable alternative to criterion measures. Ultra-short procedures may facilitate routine HRV tracking in tactical populations for status-monitoring purposes.

Insulin resistance and reduced cardiac autonomic function in older adults: the Atherosclerosis Risk in Communities study

BackgroundPrior studies have shown insulin resistance is associated with reduced cardiac autonomic function measured at rest, but few studies have determined whether insulin resistance is associated with reduced cardiac autonomic function measured during daily activities.MethodsWe examined older adults without diabetes with 48-h ambulatory electrocardiography (n = 759) in an ancillary study of the Atherosclerosis Risk in Communities Study. Insulin resistance, the exposure, was defined by quartiles for three indexes: 1) the homeostatic model assessment of insulin resistance (HOMA-IR), 2) the triglyceride and glucose index (TyG), and 3) the triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C). Low heart rate variability, the outcome, was defined by <25th percentile for four measures: 1) standard deviation of normal-to-normal R-R intervals (SDNN), a measure of total variability; 2) root mean square of successive differences in normal-to-normal R-R intervals (RMSSD), a measure of vagal activity; 3) low frequency spectral component (LF), a measure of sympathetic and vagal activity; and 4) high frequency spectral component (HF), a measure of vagal activity. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals weighted for sampling/non-response, adjusted for age at ancillary visit, sex, and race/study-site. Insulin resistance quartiles 4, 3, and 2 were compared to quartile 1; high indexes refer to quartile 4 versus quartile 1.ResultsThe average age was 78 years, 66% (n = 497) were women, and 58% (n = 438) were African American. Estimates of association were not robust at all levels of HOMA-IR, TyG, and TG/HDL-C, but suggest that high indexes were associated consistently with indicators of vagal activity. High HOMA-IR, high TyG, and high TG/HDL-C were consistently associated with low RMSSD (OR: 1.68 (1.00, 2.81), OR: 2.03 (1.21, 3.39), and OR: 1.73 (1.01, 2.91), respectively). High HOMA-IR, high TyG, and high TG/HDL-C were consistently associated with low HF (OR: 1.90 (1.14, 3.18), OR: 1.98 (1.21, 3.25), and OR: 1.76 (1.07, 2.90), respectively).ConclusionsIn older adults without diabetes, insulin resistance was associated with reduced cardiac autonomic function – specifically and consistently for indicators of vagal activity – measured during daily activities. Primary prevention of insulin resistance may reduce the related risk of cardiac autonomic dysfunction.

Influence of polypharmacy on heart rate variability in older adults at the Hiroshima Atomic Bomb Survivors Recuperation Research Center, Japan.

BackgroundMany studies have identified the risk of polypharmacy, but physiological evidence and methods of evaluation in these studies were poor. The relationship between polypharmacy and heart rate variability in older adults remains unclear. We investigated the relationship between polypharmacy in older adults, including atomic bomb survivors, and heart rate variability.MethodsWe surveyed 56 older adults who did not need nursing care assistance in the Hiroshima Atomic Bomb Survivors Recuperation Center. Chronic diseases, types of medication, and lifestyle were assessed, and heart rate variability at rest was measured. We calculated heart rate variability indices including standard deviation of normal-to-normal RR intervals (SDNN), total power (TP), and very low frequency (VLF) and analyzed the relationship between the number of daily medication types and heart rate variability indices in older adults. The differences in heart rate variability indices were analyzed using six medications as a cut-off point.ResultsParticipants included 36 atomic bomb survivors and 20 non-atomic bomb survivors. The mean number of medication types was 3.6±3.4 (mean±standard deviation). SDNN, TP, and VLF decreased with an increased number of medications in all participants (P<0.01). When the standard of polypharmacy was set to more than six types of medications, SDNN, TP, and VLF were significantly lower in older adults who took six or more medications. Additionally, the mean number of medication types among atomic bomb survivors was higher than that of non-atomic bomb survivors (P = 0.008). The SDNN was significantly lower when atomic bomb survivors took six or more medications (P<0.001).ConclusionsWe found that a lower heart rate variability in older adults, including atomic bomb survivors, is associated with polypharmacy. We showed physiological evidence of the influence of polypharmacy, which may be important for the healthy life expectancy and prognosis in older adults.

Correlations of thyroid hormone with deceleration capacity of heart rate and heart rate variability in children with hyperthyroidism

To investigate deceleration capacity of heart rate (DC), acceleration capacity of heart rate (AC), and heart rate variability (HRV) in children with hyperthyroidism and the correlations of serum thyroid hormone levels with DC, AC, and HRV. A total of 47 children with hyperthyroidism were enrolled as hyperthyroidism group and 50 healthy children were enrolled as control group. The subjects in the two groups underwent 24-hour ambulatory electrocardiography. The two groups were compared in terms of DC, AC, heart rate (HR), HRV parameters [standard deviation of normal-to-normal RR intervals (SDNN), standard deviation of average normal-to-normal RR intervals (SDANN), root mean square of successive differences between adjacent RR intervals (RMSSD), low-frequency power (LF), and high-frequency power (HF)]. The correlations of thyroid hormone indices [free triiodothyronine (FT3) and free thyroxin (FT4)] with DC, AC, and HRV were analyzed. Compared with the control group, the hyperthyroidism group had significantly lower DC, SDNN, SDANN, RMSSD, LF, and HF and significantly higher AC and HR (P<0.05). In the children with hyperthyroidism, serum FT3 and FT4 levels showed significant negative correlation with DC, SDNN, SDANN, RMSSD, LF, and HF and significant positive correlation with AC and HR (P<0.05). Children with hyperthyroidism have cardiac autonomic nerve dysfunction manifested as reduced vagal tone. Vagal tone decreases with the increasing serum thyroid hormone levels, suggesting an increased risk of cardiovascular disease.

Association Between Heart Rate Variability and Home Blood Pressure: The Toon Health Study.

Although blood pressure (BP) is regulated by the autonomic nervous system, it is not fully understood how autonomic activity affects BP at home in the general population. Subjects were enrolled from 2009 to 2012 and included 1,888 men and women aged 30-79 years. We measured casual BP in the morning during health checkups and asked participants to monitor BP at home twice in the morning and evening for 1 week. The mean of the two measurements of mean arterial pressure (MAP) was calculated. Five-minute recordings of the pulse wave from a fingertip sensor were used to determine the following indices of heart rate variability (HRV): standard deviation of normal-to-normal RR intervals (SDNN), root mean square of successive differences in RR intervals (RMSSD), high frequency (HF) power, low frequency (LF) power, and LF/HF. Sex- and age-adjusted means of casual MAP, and morning and evening MAP at home were significantly different among quartiles of SDNN, RMSSD, and HF. When further adjusted for smoking, alcohol drinking, medication for hypertension, diabetes, sleeping hours, snoring, and mental health status, the associations were somewhat attenuated. Inverse relationships were found between the means of morning home MAP, and RMSSD (P = 0.02) and HF (P = 0.051) after adjustment for confounders. The association between MAP and RMSSD, or MAP and HF was evident in individuals <65 years old. Low HF and RMSSD, which reflect impaired parasympathetic nervous system activity, were associated with increased home MAP in the morning rather than in the evening.

Functional Activity of the Autonomous Nervous System at Different Levels of Consciousness in Patients with a Brain Damage

The purpose of the study — assessment of the level of consciousness in patients with a brain damage on the basis of electrophysiological examination of the functional state of the autonomous nervous system by recording parameters of the heart rate variability (HRV). Materials and Methods . The study included 77 patients on Day 20—50 after a traumatic brain injury, anoxic injury, consequences of acute cerebral circulation disorders. The following parameters of the HRV for a 5-minute recording were accepted as criteria of norm and pathology of the autonomous nervous system (ANS) activity: (1) parasympathetic hyperactivity (hypervagal state) values with 95% confidence intervals were recorded within the accepted values for (a) SDNN (standard deviation of normal to normal R-R intervals), [41.5 —149.3 ms]; (b) rMSSD (root-mean-square of the successive normal sinus R—R interval difference in ms), [42.4—175.0 ms];(c) pNN50% (percentage of successive normal sinus RR intervals >50 ms), [8.14—54.66%]; (d) SI (Baevsky stress index), [0—80 normalized units, n. u.]; (2) the sympathetic hyperactivity recordered within the range of values for (a) SDNN [4.54—13.30 ms]; (b) rMSSD [2.25— 5.77 ms]; (c) pNN50% [0—0.109%]; (d) SI >900 n. u.; (3) the normal value of ANS parameters were recordered within the range of values for (a) SDNN [13.31—41.4 ms]; (b) rMSSD [5.78—42.3 ms]; (c) pNN50% [0.110—8.1%]; (d) SI [80—900 n. u.]. For verification of the hypervagal state, sympathetic hyperactivity or normal state, at least 3 of 4 parameters should be within the specified limits. Results . In 40 (51.9%) of 77 patients examined after a brain damage, ANS functional activity parameters were within the range of pathological values. The sympathetic hyperactivity was identified in 34 patients, and in 6 cases the hypervagal state was diagnosed. Pathological parameters of HRV were found in 80% of patients with severe forms of unconsciousness (vegetative state, coma), and only in 20% of patients with normal consciousness. Conclusion .The computer analysis of the HRV is a necessary element of examination of patients with different levels of consciousness after a brain damage of a traumatic and non-traumatic genesis. The frequency of pathological changes in the functional state of the autonomous nervous system increases significantly in groups of patients from the normal level of consciousness to the state of minimal consciousness, vegetative state, and coma. The sympathetic hyperactivity is the main type of ANS pathology in the groups of patients with minimal consciousness, in the vegetative state, and coma.

TRPA1 mediates the cardiac effects of acrolein through parasympathetic dominance but also sympathetic modulation in mice

Numerous studies have demonstrated that short-term air pollution exposure causes cardiac autonomic imbalance as measured by heart rate variability (HRV). We previously showed that a single exposure to acrolein, a ubiquitous gaseous component of air pollution, not only causes autonomic imbalance, but also increases arrhythmia through transient receptor potential A1 (TRPA1) cation channels. Thus, the goal of this study was to characterize acrolein-induced autonomic changes in both normal and TRPA1-knockout mice (KO). Conscious, unrestrained C57BL/6 (WT) and KO mice were exposed to 3 ppm acrolein for 3 h. Separate groups were treated with either atenolol (sympathetic blocker), atropine (parasympathetic blocker) or hexamethonium (autonomic neurotransmission blocker), immediately before exposure. Electrocardiogram (ECG) and heart rate (HR) were recorded continuously before, during and after exposure. Exposure to acrolein produced significant increases in standard deviation of normal-to-normal R-R intervals (SDNN), Root Mean Square of the Successive Differences (RMSSD) and Low-Frequency (LF), as well as an increase in arrhythmia in WT mice. Treatment with atenolol reduced this response while atropine enhanced it, and both drugs blocked the acrolein-induced increase in arrhythmia; hexamethonium had no effect. On the other hand, neither acrolein nor any drug had an effect in the KO mice. Thus, acrolein-induced HRV responses appear to be mediated by a combined parasympathetic and sympathetic modulation. KO mice did not demonstrate any increases in HRV with exposure to acrolein. These data demonstrate that the cardiac effects of irritant air pollutants likely involve disruption of homeostatic balance and altered regulation even in healthy animals.

Low heart rate variability relates to the progression of gastric cancer

BackgroundGastric cancer (GC) is one of the most common malignant gastrointestinal tumors with the high morbidity and mortality, affecting the quality of human life. This study aimed to identify the role of heart rate variability (HRV) in patients with GC.MethodsFrom January 2010 to June 2014, 383 consecutive patients diagnosed with GC were enrolled in this study. Clinical and pathological information from each patient were retrospectively recorded. HRV, including standard deviation of normal-to-normal RR intervals (SDNN) and root mean square of successive differences (RMSSD), were measured by electrocardiography.ResultsThe results showed that the SDNN and RMSSD in GC patients were 19.02 ± 13.58 ms and 21.64 ± 17.57 ms, respectively. HRV decreased with advanced clinical stage (P < 0.0001). HRV correlated with tumor size, tumor infiltration, lymph node metastasis and distant metastasis (P < 0.001); however, no correlation with tumor site and metastasis severity was found (P > 0.05). C-reactive protein (CRP) was higher in the low HRV group than that in high HRV group (P = 0.008).ConclusionsGC patients showed a lower HRV that was correlated with tumor stage. HRV decreased with tumor progression, which may be related to a mechanism involving vagal nerve excitement inhibiting the inflammatory reaction.

Cardiac autonomic nerve function in obese school-age children

To analyze the deceleration capacity (DC) of heart rate, acceleration capacity (AC) of heart rate, and heat rate variability (HRV) in obese school-age children, and to observe the correlations of BMI with DC, AC, and HRV in these children. A total of 108 obese school-age children were selected, including 75 cases of ortholiposis and 33 cases of dyslipidemia. A total of 103 healthy school-age children were selected as control group. All the subjects underwent 24-hour ambulatory electrocardiography. The comparisons of DC, AC, and HRV were made between the obese and control groups, as well as between children with ortholiposis and dyslipidemia in the obese group. The correlations of BMI with DC, AC, and HRV were analyzed in the obese group. The obese group showed lower DC, standard deviation of normal-to-normal R-R intervals (SDNN), standard deviation of the average normal-to-normal intervals (SDANN), root mean square of successive differences (RMSSD), low-frequency power (LF), and high-frequency power (HF) than the control group. The AC of the obese group was significantly higher than that of the control group (P<0.05). In the obese group, children with dyslipidemia had significantly lower DC, SDNN, SDANN, RMSSD, LF, and HF, but significantly higher AC and BMI, as compared with those with ortholiposis (P<0.01). In the obese group, BMI was negatively correlated with DC, SDNN, SDANN, RMSSD, and HF (P<0.05), but positively correlated with AC (P<0.05). Obese school-age children have impaired autonomic nerve function, presenting with reduced vagal tone, which is particularly prominent in those with dyslipidemia. The more obese the children, the lower the vagal tone, which may increase the risks of cardiovascular diseases.

Clinical implication of body size phenotype on heart rate variability

We compared heart rate variability (HRV) values according to the following body size phenotypes: metabolically healthy normal weight (MHNW), metabolically unhealthy but normal weight (MUNW), metabolically healthy but obese (MHO), and metabolically unhealthy obese (MUO). We retrospectively analyzed a dataset from 1200 participants who had visited the Cardiovascular Center at Korea University Guro Hospital between March 2009 and February 2014 and underwent Holter monitoring for 24h. HRV was calculated from standard deviation of normal-to-normal R-R intervals (SDNN), standard deviation of the average normal-to-normal intervals (SDANN), and root mean square of successive differences (rMSSD) measurements, and study subjects were classified according to body mass index (BMI) and presence or absence of metabolic syndrome. Various HRV indices, including SDNN, SDANN, and rMSSD, were significantly lower in MUNW subjects than in MHNW or MHO subjects, while there were no significant differences between MUNW and MUO subjects. Although BMI had no significant correlation with any HRV indices, SDNN, SDANN, and rMSSD values had significant negative correlations with waist circumference and levels of C-reactive proteins, AST, ALT, fasting glucose, and HOMA-IR. A significant positive correlation was observed between HRV index and HDL level. Furthermore, the SDNN value significantly decreased with an increase in the number of metabolic syndrome components after adjusting for other covariates. Compared to MHNW or MHO subjects, Korean men and women with the MUNW phenotype exhibited decreased HRV, suggesting that low HRV is related to adverse cardiovascular outcomes in MUNW individuals.

Heart rate variability predicts the emotional state in dogs

Although it is known that heart rate variability (HRV) is a useful indicator of emotional states in animals, there are few reports of research in dogs. Thus, we investigated the relationship between HRV and emotional states in dogs. The electrocardiogram and behavior in two situations that elicited a positive and negative emotion, in addition to baseline (when dogs were not presented any social stimuli), were recorded in 33 healthy house dogs. After testing, we chose 15seconds from each situation and baseline and calculated three HRV parameters: standard deviation of normal-to-normal R-R intervals (SDNN), the root mean square of successive heartbeat interval differences (RMSSD), and mean R-R intervals (mean RRI). In comparing these parameters with baseline, only SDNN was lower in a positive situation. In contrast, only RMSSD was lower in a negative situation. A change in HRV occurred with a stimulus eliciting emotion, and was able to distinguish between positive and negative situations. Thus, HRV is useful for estimating the emotional state in dogs.

Autonomic dysfunction in primary Sjogren's syndrome: a prospective cohort analysis of 154 Korean patients.

Background/AimsTo determine the prevalence of autonomic dysfunction among Korean patients with primary Sjogren’s syndrome (pSS) and its associations with the clinical features of pSS.MethodsWe analyzed 154 participants from the Korean Initiative of primary Sjogren’s Syndrome (KISS) as a prospective pSS cohort and 154 age- and sex-matched healthy controls. A standardized 5-minute, supine, resting heart rate variability (HRV) test was performed, and autonomic dysfunction was defined as standard deviation of normal-to-normal RR intervals (SDNN) < 30 ms in patients < 50 years old and SDNN < 20 ms in patients ≥ 50 years old. The associations between autonomic dysfunction and various clinical features of pSS were analyzed.ResultsThe overall autonomic activity in patients with pSS was significantly lower than that in controls. Autonomic dysfunction with the HRV test was observed in 35.7% of the KISS participants and was associated with a higher European League Against Rheumatism Sjogren’s Syndrome Patient Reported Index fatigue score (p = 0.024). Raynaud’s phenomenon was a more frequent clinical presentation in pSS patients with autonomic dysfunction than in those without autonomic dysfunction (29.4% and 14.4%, respectively; p = 0.048). Decreased parasympathetic activity was observed in 41.6% of pSS patients. No differences were found in the oral and ocular signs of pSS according to the decreased parasympathetic activity.ConclusionsIn Korean patients with pSS, decreased and imbalanced autonomic activity is prevalent and is associated with fatigue. However, an association between autonomic dysfunction and glandular manifestations was not detected.

Heart acceleration and deceleration capacities associated with dilated cardiomyopathy.

Heart rate deceleration capacity and acceleration capacity are novel autonomic nervous system indicators of cardiac neural regulation. Dilated cardiomyopathy (DCM) changes cardiac electrophysiology; however, how deceleration capacity and acceleration capacity associated with DCM remain unclear. To evaluate the association between heart rate acceleration capacity, deceleration capacity and DCM, 66 DCM patients with DCM and 209 controls were enrolled in the study. Demographic data, echocardiographic data, heart rate variability, deceleration capacity and acceleration capacity were collected. The association pattern between DCM and these indexes were studied by multiple logistic regression analysis. Deceleration capacity and acceleration capacity were independent risk factors for DCM with an odds ratio (OR) and 95% confidence interval (CI), determined by multiple logistic regression analysis, of 7·97 (3·87-16·42) and 0·09 (0·05-0·19), respectively. Univariate ordinal logistic regression analysis showed that acceleration capacity, fastest heart rate, standard deviation of normal-to-normal RR intervals (SDNN) and left ventricular ejection fraction (LEVF) associated with heart failure grade. The OR for each covariate was further adjusted for the effects of other significant covariates in multivariate ordinal logistic regression analysis. Acceleration capacity, fastest heart rate and LVEF were still independent risk factors in the final equation with ORs of 1·32 (1·03-1·79), 1·04 (0·01-1·07) and 0·46 (0·23-0·93), respectively. Heart rate acceleration capacity and deceleration capacity are independent risk factors for DCM, and acceleration capacity is a predictive factor for heart failure exacerbation in patients with DCM.

Antidepressants and heart-rate variability in older adults: a population-based study.

Tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) may be associated with lower heart rate variability (HRV), a condition associated with increased mortality risk. We aimed to investigate the association between TCAs, SSRIs and HRV in a population-based study. In the prospective Rotterdam Study cohort, up to five electrocardiograms (ECGs) per participant were recorded (1991-2012). Two HRV variables were studied based on 10-s ECG recordings: standard deviation of normal-to-normal RR intervals (SDNN) and root mean square of successive RR interval differences (RMSSD). We compared the HRV on ECGs recorded during use of antidepressants with the HRV on ECGs recorded during non-use of any antidepressant. Additionally, we analysed the change in HRV on consecutive ECGs. Those who started or stopped using antidepressants before the second ECG were compared with non-users on two ECGs. We included 23 647 ECGs from 11 729 participants (59% women, mean age 64.6 years at baseline). Compared to ECGs recorded during non-use of antidepressants (n = 22 971), SDNN and RMSSD were lower in ECGs recorded during use of TCAs (n = 296) and SSRIs (n = 380). Participants who started using TCAs before the second ECG had a decrease in HRV and those who stopped had an increase in HRV compared to consistent non-users (p < 0.001). Starting or stopping SSRIs was not associated with HRV changes. TCAs were associated with a lower HRV in all analyses, indicating a real drug effect. For SSRIs the results are mixed, indicating a weaker association, possibly due to other factors.

Resting heart rate, heart rate variability and functional decline in old age.

Heart rate and heart rate variability, markers of cardiac autonomic function, have been linked with cardiovascular disease. We investigated whether heart rate and heart rate variability are associated with functional status in older adults, independent of cardiovascular disease. We obtained data from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). A total of 5042 participants were included in the present study, and mean follow-up was 3.2 years. Heart rate and heart rate variability were derived from baseline 10-second electrocardiograms. Heart rate variability was defined as the standard deviation of normal-to-normal RR intervals (SDNN). Functional status in basic (ADL) and instrumental (IADL) activities of daily living was measured using Barthel and Lawton scales, at baseline and during follow-up. The mean age of the study population was 75.3 years. At baseline, higher heart rate was associated with worse ADL and IADL, and lower SDNN was related to worse IADL (all p values < 0.05). Participants in the highest tertile of heart rate (range 71-117 beats/min) had a 1.79-fold (95% confidence interval [CI] 1.45-2.22) and 1.35-fold (95% CI 1.12-1.63) higher risk of decline in ADL and IADL, respectively (p for trend < 0.001 and 0.001, respectively). Participants in the lowest tertile of SDNN (range 1.70-13.30 ms) had 1.21-fold (95% CI 1.00-1.46) and 1.25-fold (95% CI 1.05-1.48) higher risk of decline in ADL and IADL, respectively (both p for trends < 0.05). All associations were independent of sex, medications, cardiovascular risk factors and comorbidities. Higher resting heart rate and lower heart rate variability were associated with worse functional status and with higher risk of future functional decline in older adults, independent of cardiovascular disease. This study provides insight into the role of cardiac autonomic function in the development of functional decline.

Heart rate variability and the risk of Parkinson disease: The Atherosclerosis Risk in Communities study.

Autonomic dysfunction frequently occurs in the context of Parkinson disease (PD) and may precede onset of motor symptoms. Limited data exist on the prospective association of heart rate variability (HRV), a marker of autonomic function, with PD risk. We included 12,162 participants of the Atherosclerosis Risk in Communities study, a community-based cohort, without a diagnosis of PD at baseline (1987-1989) and with available HRV data (mean age = 54 years, 57% women). A 2-minute electrocardiogram was used to measure HRV. Incident PD was identified through 2008 from multiple sources, and adjudicated. Multivariable Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of PD by quartiles of HRV measurements. During a mean follow-up of 18 years, we identified 78 incident PD cases. Lower values of the root mean square of successive differences in normal-to-normal R-R intervals (rMSSD) and standard deviation of normal-to-normal R-R intervals (SDNN), markers of parasympathetic activity and total variability, respectively, were associated with higher PD risk during follow-up. In multivariate models, the HR (95% CI) of PD in the bottom quartiles of rMSSD and SDNN compared to the top quartiles were 2.1 (1.0-4.3) and 2.9 (1.4-6.1), respectively. Other measures of cardiac autonomic function, including mean R-R interval and frequency-domain measurements, were not associated with PD risk. In this prospective cohort, decreased HRV was associated with an increased risk of PD. Assessment of cardiac autonomic function may help identify individuals at risk for PD.

Effects of auditory stimulation with music of different intensities on heart period

Various studies have indicated that music therapy with relaxant music improves cardiac function of patients treated with cardiotoxic medication and heavy-metal music acutely reduces heart rate variability (HRV). There is also evidence that white noise auditory stimulation above 50 dB causes cardiac autonomic responses. In this study, we aimed to evaluate the acute effects of musical auditory stimulation with different intensities on cardiac autonomic regulation. This study was performed on 24 healthy women between 18 and 25 years of age. We analyzed HRV in the time [standard deviation of normal-to-normal RR intervals (SDNN), percentage of adjacent RR intervals with a difference of duration >50 ms (pNN50), and root-mean square of differences between adjacent normal RR intervals in a time interval (RMSSD)] and frequency [low frequency (LF), high frequency (HF), and LF/HF ratio] domains. HRV was recorded at rest for 10 minutes. Subsequently, the volunteers were exposed to baroque or heavy-metal music for 5 minutes through an earphone. The volunteers were exposed to three equivalent sound levels (60–70, 70–80, and 80–90 dB). After the first baroque or heavy-metal music, they remained at rest for 5 minutes and then they were exposed to the other music. The sequence of songs was randomized for each individual. Heavy-metal musical auditory stimulation at 80–90 dB reduced the SDNN index compared with control (44.39 ± 14.40 ms vs. 34.88 ± 8.69 ms), and stimulation at 60–70 dB decreased the LF (ms2) index compared with control (668.83 ± 648.74 ms2 vs. 392.5 ± 179.94 ms2). Baroque music at 60–70dB reduced the LF (ms2) index (587.75 ± 318.44 ms2 vs. 376.21 ± 178.85 ms2). In conclusion, heavy-metal and baroque musical auditory stimulation at lower intensities acutely reduced global modulation of the heart and only heavy-metal music reduced HRV at higher intensities.

Micronutrient and physiologic parameters before and 6 months after RYGB

BackgroundBariatric surgery is considered an effective method for sustained weight loss, but may cause various nutritional complications. The aim of this study was to evaluate the nutritional status of minerals and vitamins, food consumption, and to monitor physiologic parameters in patients with obesity before and 6 months after Roux-en-Y gastric bypass surgery (RYGB). MethodsThirty-six patients who had undergone RYGB were prospectively evaluated before and 6 months after surgery. At each phase their weight, height, body mass index (BMI), Electro Sensor Complex (ES Complex) data, food consumption, and total protein serum levels, albumin, prealbumin, parathyroid hormone (PTH), zinc (Zn), B12 vitamin (VitB12), iron (Fe), ferritin, copper (Cu), ionic calcium (CaI), magnesium (Mg), and folic acid were assessed. ResultsThe mean weight loss from baseline to 6 months after surgery was 35.34±4.82%. Markers of autonomic nervous system balance (P<.01), stiffness index (P<.01), standard deviation of normal-to-normal R-R intervals (SDNN) (P<.01), and insulin resistance (P<.001) were also improved. With regard to the micronutrients measured, 34 patients demonstrated some kind of deficiency. There was a high percentage of Zn deficiency in both pre- (55.55%) and postoperative (61.11%) patients, and 33.33% of the patients were deficient in prealbumin postoperatively. The protein intake after 6 months of surgery was below the recommended intake (<70 g/d) for 88.88% of the patients. Laboratory analyses demonstrated an average decrease in total protein (P<.05), prealbumin (P = .002), and PTH (P = .008) between pre- and postsurgery, and a decrease in the percentage of deficiencies for Mg (P<.05), CaI (P<.05), and Fe (P = .021). ConclusionDespite improvements in the autonomic nervous system balance, stiffness index markers and insulin resistance, we found a high prevalence of hypozincemia at 6 months post-RYGB. Furthermore, protein supplements were needed to maintain an adequate protein intake up to 6 months postsurgery.

A study on analysis of Heart Rate Variability in hypertensive individuals

Introduction: Hypertension is a major risk factor for coronary artery disease, stroke and heart failure. Autonomic nervous system (ANS) dysfunction is an important factor in the development and progression of hypertension. Heart rate variability (HRV) is a simple, sensitive and non-invasive tool to monitor the cardiovascular ANS function. Thus, the present study was chosen as a simple tool to assess the sympathovagal balance by analysing the HRV changes in hypertensive individuals. Aims and Objectives: To analyse Heart Rate Variability (HRV) in hypertensive individuals. Materials and Methods: The study was conducted on 30 normotensive and 30 hypertensive subjects (BP≥140/90 mm Hg, according to JNC-7 classification). Lead-II ECG was recorded using the instrument PHYSIOPAC-PP4, MEDICAID system, Chandigarh and HRV analysis was done using Kubios HRV analyser. Spectral indices of HRV such as total power (TP), normalized low frequency power (LFnu), normalized high frequency power (HFnu), ratio of low frequency power to high frequency power (LF-HF ratio), standard deviation of normal-to-normal RR intervals (SDNN), root mean square successive difference (rMSSD) and the proportion of NN50 to the total number of NN intervals (pNN50) were assessed. Results: Our results showed significantly reduced HFnu (p 0.05), SDNN (p 0.05), rMSSD (p 0.05) and pNN50 (p 0.05) in hypertensive individuals. LFnu and LF-HF ratio was significantly increased (p 0.05) in hypertensive individuals.

Cardiac autonomic responses induced by auditory stimulation with music is influenced by affinity

INTRODUCTION: We aimed to evaluate the effects of musical auditory stimulation on cardiac autonomic regulation in subjects who enjoy and who do not enjoy the music. METHOD: The study was performed in young women (18-27 years old) divided in two groups (1) volunteers who enjoyed the music and (2) volunteers who did not enjoy the music. Linear indices of heart rate variability were analyzed in the time domain. The subjects were exposed to a musical piece (Pachelbel: Canon in D Major) during 10 minutes. Heart rate variability was analyzed at rest with no music and during musical auditory stimulation. RESULTS: In the group that enjoyed the music the standard deviation of normal-to-normal R-R intervals (SDNN) was significantly reduced during exposure to musical auditory stimulation. We found no significant changes for the other linear indices. The group composed of women who did not enjoy the music did not present significant cardiac autonomic responses during exposure to musical auditory stimulation. CONCLUSION: Women who enjoyed the music presented a significant cardiac autonomic response consisting of a reduction in heart rate variability induced by the musical auditory stimulation. Those who did not enjoy the musical piece presented no such response.