SDNN Values Research Articles

Abstract 13441: Which Indices of Heart Rate Variability are the Best Predictors of Mortality After Acute Myocardial Infarction? Meta-Analysis of Observational Studies

Introduction: Cardiovascular disease is the first cause of death globally with myocardial infarction as the main event. Heart rate variability (HRV) has been associated with an increased risk of mortality post-myocardial infarction. However, which indices of heart rate variability are the best predictors for total and cardiac mortality post-myocardial infarction remains unclear. Predict mortality risk by these indices, is important as HRV is a low-cost, low-invasive, and easy biomarker to interpret. Hypothesis: Indices evaluating heart rate variability are differentially associated with cardiac and total mortality, but to date, there is no evidence about which is the best for these outcomes Methods: PubMed, Google Scholar, Embase, Cochrane databases, and grey literature were searched for studies with HRV as a predictive mortality marker. Two authors independently selected papers and extracted data. Disagreements were solved with a third author. Clinical and statistical heterogeneity was assessed. Forest and funnel plot graphs were made. HRV indices included were SDNN, SDANN, HRV index, Total power, RMSSD, pNN50, LF, HF, ULF, VLF, and LF/HF. Sensitivity analysis, cumulative and regression meta-analysis were performed. Stata 16 was used for statistical analysis. Results: From 338 articles found, 29 were included. Low values of SDNN, HRV index, HF, ULF, and VLF showed statistically significant association with cardiac mortality, but HRV index had the highest association RR: 5.10 (CI95% 3.92 - 6.65, I 2 of 22%). For overall mortality, SDNN, HRV index, LF, VLF y ULF had statistically significant association, but HRV index was the best index, RR:3.60 (CI95% 2.52- 5.15, I 2 0%). Both associations had high consistency in subgroup analysis, with quality of articles, year of publication, and different cut-off points. Conclusions: the best index associated with cardiac and total mortality post-myocardial infarction is low values of HRV index.

Cardiovascular autonomic nervous system function and hip fracture risk: the Cardiovascular Health Study.

Autonomic nervous system function modulates bone remodeling in rodent osteoporosis models. We tested whether cardiovascular autonomic function is associated with hip fracture risk in humans. Participants were 1299 subjects from the Cardiovascular Health Study (mean age 72.8years). Eight heart rate variability (HRV) measures (time and frequency domains, detrended fluctuation analysis variables, and heart rate turbulence) were derived from 24-h Holter monitor scans in sinus rhythm. Median follow-up for incident hip fracture was 14.7years [IQR 9.1, 20.2]. Cox proportional hazards models were used to calculate hazard ratios (95% confidence intervals, CI). There were 144 hip fractures among 714 women (1.31 [1.06, 1.61] per 100-person years) and 46 among 585 men (0.62 [0.43, 0.90] per 100 person-years). From among HRV variables examined, a one standard deviation (SD) higher variation between normal heart beats over 24h (the SD of NN intervals [SDNN]) was associated with a multivariable-adjusted lower hip fracture risk (HR [Formula: see text] 0.80; 95% CI 0.65-0.99; p = 0.04) in women. The adjusted association between very low frequency power, and hip fracture was borderline statistically significant in women (HR [Formula: see text] 0.82; 95% CI, 0.66-1.00; p = 0.06). When the 8 HRV variables were considered conjointly and adjusted for each other's association with hip fracture risk, a 1 SD higher SDNN value was significantly associated with reduced hip fracture risk in women (HR 0.74; 95% CI, 0.50-0.99; p = 0.05). No HRV variables were associated with hip fracture in men. In older women, increased heart rate variation is associated with hip fracture risk.

Effects of exercise training on heart rate variability in children and adolescents with pulmonary arterial hypertension: a pilot study.

Pulmonary arterial hypertension (PAH) is often associated with cardiac autonomic dysfunction, and heart rate variability (HRV) as marker of cardiac autonomic function is even related to disease severity. Knowledge about the effects of physical activity on HRV is limited in these patients. We aimed to assess whether HRV parameters can be influenced by a supervised exercise training program and whether respective changes are related to levels of activity. Six children and adolescents with moderate PAH (3 female, mean age 15.0±4.4 years; mean pulmonary to systemic arterial pressure ratio 0.5±0.2) performed supervised endurance and resistance training for 16 weeks. PAH-specific targeted medication remained unchanged during the study period. HRV was assessed before training and after 16 weeks of training by the use of ECG Move accelerometers. HRV indices included: standard deviation of normal-to-normal (NN) intervals (SDNN), square root of the mean of the sum of the squares of differences between successive NN-intervals (RMSSD), proportion of the number of pairs of successive normal-to-normal intervals that differ by more than 50 ms divided by total number of normal-to-normal interval (pNN50), and the Baevsky stress index (BSI) calculated by the histogram method. Before and after the training program, SDNN, RMSSD and pNN50 correlated with the level of physical activity. Mean values of SDNN, RMSSD and pNN50 did not change significantly due to the training program. Notably, activity level depending SDNN increased markedly after the exercise program (during activity +12.4%, at rest +6.6% and reclining +8.1%, Hedge's g of 0.28, 0.14 and 0.27, respectively). BSI decreased during activity due to the training program reflecting a reduction of stress level (Hedge's g -0.87 indicating an effect of clinical relevance). According to the experience of this pilot study a workout program of 16 weeks revealed an activity level dependent effect on parameters of autonomic cardiac function in children and adolescents with PAH. This mechanism might contribute to the positive effects of exercise training in patients with PAH.

Heart Rate Variability as an Indicator of Autonomic Nervous System Disturbance in Behcet's Disease.

BackgroundBehçet’s disease (BD) is a multisystemic vasculiti where cardiac involvement is not common. Previous studies have shown that the incidence of ventricular arrhythmia and sudden cardiac death (SCD) is higher in patients with BD than in the healthy population. Among various possible explanations, autonomic nervous system (ANS) dysfunction has been suggested. Few studies have evaluated ANS function in patients with BD, and the results obtained are controversial.ObjectiveWe aimed to assess cardiac autonomic function by heart rate variability (HRV) in patients with BD; to evaluate circadian changes in HRV; and to study the relationship between HRV parameters and disease parameters.MethodsThirty-six patients with Behçet’s disease (median age 42 years, 28 men) and 36 age- and sex-matched healthy volunteers were included. HRV analyses were performed in the time and frequency domains for the entire 24-hour period and for the daytime and nighttime periods. BD activity was studied with Behcet’s disease current activity form (BDCAF).ResultsPatients with BD had significantly lower values of SDNN compared to controls. PNN50, RMSSD, and HF components mean values were significantly reduced in patients than in controls implying parasympathetic impairment. LF was comparable between the two groups, whereas LF/HF ratio was significantly higher in BD group. The circadian rhythm of HRV was preserved in patient group. There was no significant correlation of CRP or disease duration with HRV indices in Behçet’s subjects. BDCAF score was found to be negatively correlated with LF/HF.ConclusionPatients with BD, despite no cardiovascular involvement, have reduced parasympathetic activity compared with controls. However, circadian rhythms of autonomic function were preserved. As known, there is strong evidence for the role of the ANS in the pathogenesis of ventricular arrhythmias. Thus, being a practical tool, HRV can be an interesting approach for the rhythmic follow-up of BD patients.

249 Overnight heart rate variability depends on age, gender, and day of the week: a field observation using a smart bed platform

Abstract Introduction Heart rate variability (HRV) is commonly used to assess the activity of the autonomic nervous system (ANS). ANS function changes, reflected in HRV, result from factors including lifestyle, aging, cardiorespiratory illnesses, sleep state, and physiological stress. Despite broad interest in HRV, few studies have established normative overnight HRV values for a large population. To better understand population level HRV changes, ecologically-valid, overnight sleep SDNN (standard deviation of all normal heartbeat intervals, lower HRV is reflected by lower SDNN) values have been analyzed for a large sample of Sleep Number 360 smart bed users. Methods Overnight SDNN values were obtained over the course of 18.2M sleep sessions from 379,225 sleepers (48 ± 14.7 sessions/user). 50.9 percent of sleepers were female. The age was normally distributed with mean ± SD of 52.8 ± 12.7 years (range 21 to 84). Heartbeat intervals used to compute SDNN were extracted from a ballistocardiogram (BCG). BCG-based HRV estimation during sleep has previously been validated against ECG-based HRV with an R-square of 0.5. Results Using a Generalized Linear Model, significant cross-sectional associations with SDNN were observed for three variables of interest: age, gender, and day-of-the-week. For sleepers under 50, SDNN declined at a rate of about 2.1 ms/year, then leveled off for sleepers aged 50-65, and increased slightly thereafter. Women under 50 displayed lower, more slowly declining, SDNN values than men, but this trend reversed for sleepers over 50. Throughout the week, SDNN values followed a U-shaped (women) or L-shaped (men) pattern, where values were highest during the weekend and lowest at mid-week. Conclusion Using a smart bed to unobtrusively measure overnight SDNN values for a large set of sleepers in an ecologically valid environment, reveals significant effects of age, gender, and day of the week on overnight SDNN. Support (if any):

English

Fibromyalgia is a disease characterized by conical pain associated with autonomic dysregulation of the sufferer, without many treatment alternatives. The objective of this study was to find out the relationship between physical exercise in an aquatic environment, pain perception and cardiovascular autonomic control in adult women suffering from fibromyalgia. The sample consisted of 15 women diagnosed with fibromyalgia who participated in 24 40-minute exercise sessions in a water environment. Anthropometric measures, heart rate variability (HRV) and pain perception (PCS) were evaluated in four experimental times (t1, baseline; t2, session 8; t3, session 16; t4, session 24). In addition, the perception of pain was evaluated in each session through VAS. The results show that the perception of pain through VAS decreased when comparing all the means evaluated before and after each session (p <0.05). In the PCS application, a lower Total Pain and Rumination was obtained when comparing t1 with t4. HRV values showed that SDNN and RMSSD were higher after the session, when t4 was compared with t1 (p <0.05). The mean heart rate decreased at the end of the sessions, showing a better adaptation to exercise. The relationship between pain and cardiac measurements was given by a positive correlation in the pain domains recorded before the sessions and the RMSSD and SDNN values. In conclusion, the practice of physical exercise in an aquatic environment would indicate a lower perception of pain and a better cardiac autonomic response in women with fibromyalgia.

Reduced heart-rate variability and increased risk of hypertension-a prospective study of the ELSA-Brasil.

Although autonomic disturbances are known to precede hypertension onset, the risks underlying different ranges of blood pressure and impaired cardiac autonomic modulation are still unknown. This study aimed to identify the risk of hypertension incidence related to low heart-rate variability profile in normotensive blood pressure subcategories: normal (<120/80 mmHg) and prehypertension (120/80-139/89 mmHg) in a 4-year follow-up. 7665 participants free of hypertension at baseline were examined. They were allocated into one of two groups (<P25 and ≥P25) based on age-specific value distributions of heart-rate variability ranges presented in the literature. The relationship between heart-rate variability parameters (SDNN, RMSSD, VLF, LF, and HF) and hypertension incidence was analyzed using Poisson regression. The reference for the independent variable in these regressions was the dataset with all HRV values ≥P25. After full adjustments for age, sex, ethnicity, educational level, body mass index, smoking status, glucose, insulin, dyslipidemia, alcohol consumption, and physical activity, low values for all heart-rate variability indices were significantly associated with an increased relative risk of developing hypertension in the overall sample. Individuals with normal BP levels presented an increased risk for low SDNN, VLF, and LF values, whereas the risk in prehypertensive participants was only verified for low VLF. In conclusion, cardio autonomic disturbances precede the incidence of clinical hypertension and are potentially involved in its pathophysiological basis and progression. Even individuals with normal blood pressure may be at an increased risk for future hypertension in the presence of reduced cardio autonomic control.

Basic indices parameters of the vegetative status in students of the cadet corps

Introduction. Training in the cadet corps involves an increase in physical activity against a background of high informatization, which affects the autonomic nervous system’s functional capabilities and adaptation to stress. Materials and methods. The observation group consisted of 74 male students of the Cadet Corps (CC). The comparison group consisted of 26 boys aged 10-13 years who studied in a public secondary school (PSS). To evaluate the mode of physical activity, nutritional status, fitness, physical performance the authors performed bioimpedance analysis of body composition. The assessment of the vegetative status was carried out on the basis of the results of cardiointervalography with an active clinoorthostatic test. Results. Analysis of the personal data showed a great commitment to sports among the CC students. Cadets showed significantly higher values of the phase angle, active cellular and musculoskeletal mass, basic and specific metabolism. When recording cardiointervalography of rest in children of the observation group relative to the comparison group, statistically significant differences were revealed between the values of SDNN, RMSSD, variation range, vegetative balance index, rhythm vegetative index of physical exertion by 1.2-1.6 times. In 71.2% of cadets, the power of the heart rate variability spectrum corresponded to a high level. In children from the observation group, the initial vagotonia was recorded 2.2 times more often, and hypersympathicotonia - 7.0 times less often than in the comparison group. In the structure of autonomic reactivity in cadets, the hypersympathicotonic variant prevailed. Conclusion. The results of the analysis of the component composition of the body indicate sufficient fitness, physical activity and physical working capacity in CC students. The vegetative status of cadets is characterized by the predominance of the parasympathetic influence in the regulation of the heart rate. The hypersympathicotonic variant of autonomic reactivity indicates the exertion of adaptation processes to stress.

Influence of aerobic fitness on the correspondence between heart rate variability and ventilatory threshold

The aims of this study were to verify the correspondence between heart rate variability (HRV) and ventilatory thresholds during a progressive exercise test and the relationship with low and high aerobic fitness levels. Twenty male volunteers (29.5±6.2 years; 75.9±13.0 kg; 175.0±7.4 cm) were recruited. The subjects were allocated to two groups according to their VO2max &lt;48.8 ml•kg−1•min−1 (low cardiorespiratory fitness group) (n=10) and &gt;48.81 ml•kg−1•min−1 (high cardiorespiratory fitness group) (n=10). A progressive test was performed, consisting of 3-min stages beginning at 25 watts and increasing by 25 watts every 3-min. The HRV threshold (HRVT) and ventilatory threshold (VT) analyses were performed through visual inspection. The comparisons with RMSSD values in percentage of maximum workload resulted in a higher effect size (ES) than the SDNN values. The VO2 in the high cardiorespiratory fitness group at VT (+32%), HRVTRMSSD (+27%), and HRVTSDNN (+31%) was signifi cantly higher compared to the group with low cardiorespiratory fitness. Higher values were observed for relative load (W•kg-1) at VT and HRVTSDNN in the high cardiorespiratory fitness group in comparison with the low cardiorespiratory fitness group (P&lt;0.05), but no difference for VT and HRVTRMSSD. Signifi cant correlations between at VT and HRVTSDNN (r=0.77) were found only in the low cardiorespiratory fitness group. Cardiorespiratory fitness should be regarded as a factor for HRVT evaluation. The HRVTSDNN was closer to the VT in the low cardiorespiratory fitness group than the HRVTRMSSD, however, the use of vagal modulation assessed using the HRV parameter was more sensitive to observe possible differences regarding cardiorespiratory fitness.

Influence of aerobic fitness on the correspondence between heart rate variability and ventilatory threshold

The aims of this study were to verify the correspondence between heart rate variability (HRV) and ventilatory thresholds during a progressive exercise test and the relationship with low and high aerobic fitness levels. Twenty male volunteers (29.5±6.2 years; 75.9±13.0 kg; 175.0±7.4 cm) were recruited. The subjects were allocated to two groups according to their VO2max &lt;48.8 ml•kg−1•min−1 (low cardiorespiratory fitness group) (n=10) and &gt;48.81 ml•kg−1•min−1 (high cardiorespiratory fitness group) (n=10). A progressive test was performed, consisting of 3-min stages beginning at 25 watts and increasing by 25 watts every 3-min. The HRV threshold (HRVT) and ventilatory threshold (VT) analyses were performed through visual inspection. The comparisons with RMSSD values in percentage of maximum workload resulted in a higher effect size (ES) than the SDNN values. The VO2 in the high cardiorespiratory fitness group at VT (+32%), HRVTRMSSD (+27%), and HRVTSDNN (+31%) was signifi cantly higher compared to the group with low cardiorespiratory fitness. Higher values were observed for relative load (W•kg-1) at VT and HRVTSDNN in the high cardiorespiratory fitness group in comparison with the low cardiorespiratory fitness group (P&lt;0.05), but no difference for VT and HRVTRMSSD. Signifi cant correlations between at VT and HRVTSDNN (r=0.77) were found only in the low cardiorespiratory fitness group. Cardiorespiratory fitness should be regarded as a factor for HRVT evaluation. The HRVTSDNN was closer to the VT in the low cardiorespiratory fitness group than the HRVTRMSSD, however, the use of vagal modulation assessed using the HRV parameter was more sensitive to observe possible differences regarding cardiorespiratory fitness.

Autonomic support of endurance, strength and speed performance in athletes

Examining the autonomic support of muscular activity in athletes enables an assessment of the ANS impact on achieving a high-level of sports performance at different ages, an identification of interaction patterns between the ANS divisions in the process of short-term and long-term adaptation to muscular load, identifying the features of the cardiovascular system autonomic regulation in athletes training different physical performanceAim. To examine heart rate variability (HRV) changes in athletes depending on the training session mode.Material and methods. A total of 104 athletes (84 men and 20 women) were enrolled in the study: 63 – endurance-trained athletes, 31 – strength-trained and 10 – speed-trained athletes. The mean age of the athletes was 21.75 ± 3.32 years. Among them, there were Masters of Sports of International Class (MSIC) – 2 athletes, Masters of Sports (MS) - 25, Candidates Master of Sports (CMS) – 48, First-Class athletes – 29. All the athletes underwent HRV analysis on the device “Cardio+” (NPP “Metekol”, Nizhyn, Ukraine).Results. HRV in the endurance and strength athletes indicated a predominance of heart rate (HR) by 11.4 % (61.03 ± 10.19 vs. 68.00 ± 7.72 bpm, P = 0.004), Mode (Mo) value (954 (860; 1103) vs. 868 (798; 954) ms) by 9.0 % (P = 0.004) and shorter mean RR interval duration (Mean) by 11.7 % (1002.45 ± 168.59 vs. 885.22 ± 98.98 ms, P = 0.002) in comparison with the strength athletes. The endurance athletes had significantly lower values of SDNN by 7.6 % (P = 0.048), RMSSD by 35.5 % (P = 0.029), SDANN by 26.4 %, and the predominance of Mo by 4.1 % (P = 0.016) in contrast to the speed athletes. There was no statistically significant difference between other HRV parameters between the endurance and speed athletes. Comparison of HRV between the strength and speed athletes revealed that the strength athletes had significantly 8.8 % (P = 0.042) higher HR (68.00 ± 7.72 vs. 62.00 ± 7.14 bpm). Compared with the speed athletes, the strength athletes had significantly shorter RR interval duration (885.22 ± 98.98 vs. 969.56 ± 112.28 ms) by 9.5 % (P = 0.046), higher values of SDNN by 9.5 % (P = 0.017), RMSSD by 68.9 % (P = 0.012), SDANN by 71.8 % (P = 0.015), CVr, % by 15.0 % (P = 0.045), Mo by 5.4 % (P = 0.029) that was indicative of sympathetic hyperactivity in the strength athletes.Conclusions. The endurance and speed athletes did not differ from each other in all the spectral and the vast majority of time-domain HRV parameters, except for SDNN, RMSSD, SDANN andMo. The strength athletes differed from the endurance athletes by higher tone of the sympathetic arm of the ANS, as evidenced by significantly 11.4 % higher heart rate, 11.7 % shorter RR interval duration and 9.0 % lower Mo value. The speed and endurance athletes differed from the strength athletes by higher parasympathetic tone as evidenced by significantly 8.8 % (P = 0.042) lower heart rate, 9.5 % (P = 0.046), higher RR interval duration, values of SDNN by 9.5 % (P = 0.017), RMSSD by 68.9 % (P = 0.012), SDANN by 71.8 % (P = 0.015), CVr, % by 15.0 % (P = 0.045), Mo by 5.4 % (P = 0.029).

Evaluation of heart rate variability using 24-hour Holter electrocardiography in hypertensive patients.

BackgroundHypertension (HTN) remains a serious risk factor for cardiovascular mortality across the world. Hypertensive state has been shown to be associated with autonomic nervous function. This study aimed to explore the association between autonomic nervous impairment assessed by heart rate variability (HRV) and HTN.MethodsA total of 52 hypertensive and 55 non‐hypertensive patients were consecutively studied using 24‐hour Holter. The hypertensive patients were grouped into controlled blood pressure (BP) and uncontrolled BP. This study compared HRV in non‐hypertensive and hypertensive patients; and hypertensive patients with controlled and uncontrolled BP. HRV parameters include time and frequency domain.ResultsMean age for hypertensive and non‐hypertensive patients were 53.58 ± 14.31 and 44.89 ± 16.63 years old, respectively. Median (IQR) SDNN for hypertensive and non‐hypertensive group were 109.00 (90.00‐145.00) and 129.00 (107.00‐169.00), respectively. SDNN, ASDNN, rMSSD, pNN50, BB50, VLF, and HF values were significantly lower in the hypertensive group compared to non‐hypertensive group (all P < .05). A multiple regression analysis showed that HRV parameters: SDANN, ASDNN, rMSSD, and LF values were independent risk factors of HTN. SDNN, SDANN, ASDNN, VLF, LF, and HF values were significantly lower in the uncontrolled BP compared to controlled BP group (all P < .05). A multiple regression analysis showed that HRV parameters: SDNN, SDANN, rMSSD, and HF values were independent risk factors of uncontrolled BP in hypertensive patients.ConclusionsOur study showed that cardiac autonomic nervous impairment, as demonstrated by reduced HRV, is significantly associated with HTN. Decreased HRV was more evident in uncontrolled BP than in controlled BP group.

Assessment of heart rate variability parameters in the age subgroups of patients with arterial hypertension

Age is one of the main known risk factors for cardiovascular diseases. The ageing of the body and arterial hypertension are associated with progressive dysfunction of the autonomic nervous system, which may be one of the mechanisms underlying an increased cardiovascular risk. The aim of the paper was to assess heart rate variability parameters in the age subgroups of patients with arterial hypertension. The heart rate variability parameters were compared in a total of 139 patients with untreated arterial hypertension (mean age 45.2 ± 10.5 years, men – 69% of the study group) in the following subgroups distinguished by age: ≥45 years (n = 72) and &lt;45 years (n = 67). A temporal analysis of the heart rate variability parameters in 24-hour Holter ECG (SDNN, rMSSD, pNN50) was conducted for 24 hours, and for the day and night periods. In addition, a spectral analysis (LF, HF, TP, LF/HF ratio) was performed. The recorded values of SDNN, rMSSD, pNN50, TP as well as night-time HF were lower in the group of patients aged ≥45 years compared to the younger group. The results confirm that in patients with arterial hypertension older age is associated with a shift of the autonomic balance towards sympathetic activity, which may translate into an additional increase in cardiovascular risk.

Изменение вариабельности сердечного ритма у иностранных студентов в условиях среднегорья

Prenosological assessment of the functional state of students studying in different climatic and geographical conditions is a very important task, since it allows timely detection of conditions that precede pathologies in students and contributes to the preservation of health. Goal. Study of the state of the regulatory mechanisms of the cardiovascular system in foreign students living and studying in the midlands. Materials and methods. The study involved 342 first- and third-year students aged 20.0±1.9 years from India. The survey was carried out in the conditions of the low mountains (760 m above sea level, control group) and the midlands (1650 m above sea level). The main time and spectral parameters of HRV were recorded within 5 minutes using the hardware and software complex Psychophysiologist. Results. The comparative assessment showed that students living in the conditions of the midlands had low values of SDNN, TP, VLF, LF and HF and high indicators of AMo, HR, SI, which indicates the predominance of central regulatory mechanisms and the shift of the vegetative balance towards the sympathetic link in this group. Conclusion. The revealed changes in the spectral and temporal parameters of HRV in midlands students characterize the idea of a regulatory and adaptive state of the body, in which energy and metabolic resources are activated, primarily the circulatory system, aimed at maintaining homeostasis in changing environmental conditions.

Characteristics of Autonomic Regulation of the Heart Function in Musicians Playing Wind Instruments

We compared measures of the sympatho-vagal balance in heart regulation and cardiovagal baroreflex sensitivity (BRS) between musicians playing wind instruments (n = 23) and non-musicians (n = 19) to elucidate whether playing wind instruments is associated with chronic alterations in autonomic cardiovascular control. The arterial blood pressure was measured and ECG was recorded under resting conditions, and the Valsalva maneuver was conducted. The main HRV parameters were calculated, and BRS values were estimated using a sequence method. Musicians were characterized by a higher average heart rate at rest, lower values of the parasympathetic-related HRV parameters, i.e., RMSSD, pNN50%, HF, and SD1, together with lower values of SDNN and total HRV power. The Valsalva maneuver estimates (BRS) did not differ significantly between musicians and non-musicians. Thus, certain HRV parameters differed significantly between the examined groups. Musicians were characterized, in general, by lower vagal activity and sympathetic predominance. There was no difference in the BRS.

Delirium in patients with hip fracture is associated with increased heart rate variability.

Heart rate variability (HRV) is a method to assess the autonomic nervous system and reflects possibly central brain states. HRV has previously not been examined in patients with hip fracture and delirium. To explore HRV parameters in hip fracture patients with and without delirium. Patients admitted to Oslo University Hospital with hip fracture and sinus rhythm in electrocardiogram (ECG) were included. Delirium was diagnosed using the confusion assessment method. HRV was assessed preoperatively after a relaxing period of five minutes, by measuring an ECG signal over 5min. Parameters in time domain (the standard deviation of the QRS distances-SDNN) and frequency domain (total power (TP), low frequency (LF), high frequency (HF) and LF/HF ratio) were calculated. Seventy-five patients were included in the study, and 21 of them had subsyndromal delirium and were excluded from the analysis. Fifty-four patients with a mean age of 83.5years (SD 8.6, 78% females) were included. Twenty-six patients (48%) had preoperative delirium, 11 (20%) developed delirium postoperatively, whereas 17 (31%) never developed delirium. SDNN, TP and HF values were significantly higher in patients with delirium compared to patients without delirium, and LF and LF/HF were lower. Patients developing postoperative delirium had decreased LF and increased HF before symptom onset. Increased SDNN, TP and HF and decreased LF values might reflect an abnormal stress response in delirium. HRV measurements in patients with hip fractures provide additional information beyond heart rate and might be used to identify relevant pathophysiological factors in delirium.

Postural Taşikardi Sendromu Hastalarında Kalp Hızı Değişkenliğinin Değerlendirilmesi

Purpose: Postural tachycardia syndrome (POTS) is a disease associated with dysautonomia. Disruption of the sympathetic/parasympathetic balance is the main pathophysiological mechanism. The aim of this study was to evaluate this imbalance with mean heart rate and spectral parameters of heart rate variability measured by ambulatory rhythm monitoring. Patients and methods: One hundred and ninety-three patients with negative HUT test results and without any chronic disease enrolled in the study between 2014 and 2018. POTS was diagnosed when a 30 beats per minute increase at heart rate compared to baseline was observed during the first 10 minutes of the 70 ͦ tilt test. Patients were divided into two groups as POTS (n=27) and non POTS (n=166). Results: POTS was diagnosed in 27 (%13.9) of the 193 patients with negative HUT. Spectral parameters of heart rate variability as SDNN, SDANN, rMSSD and pNN50 values were similar between groups. Average heart rate was significantly higher in POTS patients when compared with non-POTS patients (%80 vs%47.8, p=0.024). Average heart rate above 75 beats per minutes was the only independent predictor for POTS [OR: 4.608 (1.447-14.705), p=0.01]. Conclusion: Evaluation of average heart rate by 24-hour ambulatory rhythm monitoring may be an important parameter in individuals with POTS without structural heart or chronic disease. &nbsp

ДИНАМИКА ПОКАЗАТЕЛЕЙ ВАРИАБЕЛЬНОСТИ РИТМА СЕРДЦА У ДЕТЕЙ, ОПЕРИРОВАННЫХ ПО ПОВОДУ ДЕФЕКТА МЕЖЖЕЛУДОЧКОВОЙ ПЕРЕГОРОДКИ В ПРОЦЕССЕ САНАТОРНО-КУРОРТНОГО ЛЕЧЕНИЯ

The purpose of the study is to study the effectiveness of medical rehabilitation in children operated on for a ventricular septal defect, based on the dynamics of heart rate variability indicators. Material and methods of research. Heart rate variability was evaluated in 75 children operated on for ventricular septal defect. The control group (CG) consisted of 30 healthy children. The effectiveness of medical rehabilitation was assessed by the dynamics of heart rate variability indicators. Children of the 1st group (20 people) took the cardiometabolic drug Elkar at a dose of 30 mg/kg/day for 1 month. With children of the 2nd group (20 people) for 3 months, Nordic walking classes were held (NW). In addition, children of the 2nd group received the drug Elkar for 1 month (30 mg/kg). Results. According to the time analysis of heart rate variability, operated children had significantly lower values of SDNN 82 [69;103] (p&lt;0.001), SDANNi 50.5 [39;87] (p&lt;0.05), SDNNi 69.5 [54;80] (p&lt;0.05), rMSSD 50.5 [39;87] (p&lt;0.05), pNN50 % 18.4 [6.7;28.3] (p&lt;0.05) lower power in the high-frequency range of the spectrum (p&lt;0.001) and a change in the vegetative balance towards the predominance of the sympathetic division of the autonomic nervous system (LF/HF=3.16, p=0.009) than in the control group. After the treatment, there was no reliable HRV dynamics in children who received Elcar. There was a significant difference between SDNN and rMSSD with KG. In the second group, there was a significant increase in HRV according to SDNN data by 37.7 % (p&lt;0.01), SDANNi by 45.6 % (p&lt;0.05), rMSSD by 6.5 % (p&lt;0.05), pNN50 % by 32.7 % (p&lt;0.05). The difference in indicators with CG is leveled. Conclusions. In children operated on for VSD, there was a decrease in the parameters of the time analysis of HRV in comparison with healthy peers (p&lt;0.05). The combined use of Nordic walking and Elkar have a normalizing effect on the HRV, causing a decrease in the tension of the Central circuit of heart rate regulation, significantly increasing the parasympathetic effect on the heart rate.

The correlations between posterior scleral profile and autonomic dysfunction in normal tension glaucoma

AbstractPurposeTo investigate the association between autonomic dysfunction and posterior scleral profile in normal tension glaucoma.DesignObservational, cross‐sectional study.ParticipantsTwo hundred eight NTG patients.MethodComplete ophthalmic examination was performed in all patients including heart rate variability to evaluate autonomic dysfunction. Posterior scleral profile, which was identified by the disc tilt ratio, disc torsion, disc foveo angle and peripapapillary area(PPA) to disc ratio was measured from disc photographs. Patients were classified into the two groups according to the standard deviation value of the qualified normal to normal intervals(SDNN) of the heart‐rate‐variability assessment. Group 1 consisted of patients within the one standard deviation from the average of the SDNN measurements. And Group 2 consisted of patients outside one standard deviation from the average of the SDNN measurements, indicating that they had too higher or too lower SDNN of HRV. So Group 2 having deviated value was thought to have abnormality in HRV. Two groups were compared. Logistic regression analysis was used to determine the relationship between posterior scleral profile and abnormality of heart rate variability.Main outcome and measureAssociation between posterior scleral profile(axial length, tilt ratio, torsion ratio, disc foveo angle, PPA to disc ratio) and autonomic dysfunction.ResultsThe mean value of SDNN in 208 NTG patients was 33.71 and the standard deviation was 18.16. Group1 had a SDNN values between 15.55 and 51.87 and Group 2 had a SDNN value less than 15.55 or greater than 51.87. Among 208 NTG eyes, 164 (78.8%) were group 1 and 44 (21.2%) were group 2. Axial length was significantly longer in Group 2 than Group 1 (p = 0.008). Degree of disc torsion were significantily higher in Group 2 than group 1 (p &lt; 0.001). Although just short of statistical significance (p = 0.058), disc tilt ratio was higher in group 2. Torsion degree was the only factor related to heart rate variability in both univariate (p &lt; 0.001) and multivariate (p = 0.008) logistic regression analyses.ConclusionOur study results showed that the dysfunction of an autonomic control is associated with posterior scleral profile such like disc tilt ratio, torsion degree, axial length.

Heart rate variability in sick sinus syndrome: does it have a diagnostic role?

Hypothesis of our study was that the irregular rhythm of sick sinus syndrome (SSS) was characterized by an augmented HRV. Objective was to assess whether SSS patients had a typical HRV profile. We screened all 1947 consecutive Holter ECGs performed in our Units of Vascular Medicine and Internal Medicine and Cardioangiology at the University of Palermo (Italy) from April 2010 to September 2014. Among these, we selected 30 patients with ECG criteria of SSS. They were compared to 30 patients without SSS matched for age, sex and comorbidities. The SSS group had a lower mean heart rate (HR) (P=0.003), and a longer mean NN max-min longer (P<0.0005) compared to control group. SSS group had higher mean pNN50 (P=0.043), mean RMSSD (P=0.006), mean SDNN (P=0.021), and mean SDNNi (P=0.005) as compared with control group. Moreover, HR ≤64.5 bpm, NN max-min>1355 msec, pNN50>16.08, RMSSD>50.2, SDNN>151.94, and SDNNi>71.1 showed a predictive value for diagnosis of SSS. The positivity of all 6 variables according to the aforementioned cut-offs ensured a positive predictive value of 100% and the negativity of all 6 variables had a negative predictive value of 94% for diagnosis of SSS. Among SSS patients, we did not observe any correlation between HR and HRV variables. SSS patients have a HRV profile characterized by: low HR, long NN max-min interval, and elevated pNN50, RMSSD, SDNN and SDNNi values with specific diagnostic cut-offs for diagnosis of SSS. Moreover, we found the absence of correlation between HR and all time-domain HRV variables in SSS patients.