Spectral Analysis Of Heart Rate Variability Research Articles

Full-Term and Preterm Newborns Differ more Significantly in Photoplethysmographic Waveform Variability than Heart Rate Variability

Background: Features of cardiovascular autonomic regulation in infants are poorly studied compared with adults. However, the clinical significance of autonomic dysfunction in infants is very high. The goal of our research was to study the temporal and frequency-dependent features, as well as low-frequency synchronization in cardiovascular autonomic regulation in full-term vs. preterm newborns, based on the analysis of their heart rate variability (HRV) and photoplethysmographic waveform variability (PPGV). Methods: The study included three groups of newborns: 64 full-term newborns (with a gestational age at birth of 37–40 weeks) with a physiological course of the neonatal adaptation; 23 full-term newborns (with a gestational age at birth of 37–40 weeks) with a pathological course of the neonatal adaptation; and 17 preterm newborns (with a postconceptional age of 34 weeks or more). We conducted spectral analysis of HRV and PPGV, along with an assessment of the synchronization strength between low-frequency oscillations in HRV and in PPGV (synchronization index). We employed several options for the boundaries of the high-frequency (HF) band: 0.15–0.40 Hz, 0.2–2 Hz, 0.15–0.8 Hz, and 0.24–1.04 Hz. Results: Preterm newborns had higher heart rate, RMSSD, and PNN50 values relative to both groups of full-term newborns. Values of SDNN index and synchronization index (S index) were similar in all groups of newborns. Differences in frequency domain indices of HRV between groups of newborns depended on the considered options of HF band boundaries. Values of frequency domain indices of PPGV demonstrated similar differences between groups, regardless of the boundaries of considered options of HF bands and the location of PPG signal recording (forehead or leg). An increase in sympathetic influences on peripheral blood flow and a decrease in respiratory influences were observed along the following gradient: healthy full-term newborns → preterm newborns → full-term newborns with pathology. Conclusions: Differences in frequency domain indices of autonomic regulation between the studied groups of newborns depended on the boundaries of the considered options of the HF band. Frequency domain indices of PPGV revealed significantly more pronounced differences between groups of newborns than analogous HRV indicators. An increase in sympathetic influences on peripheral blood flow and a decrease in respiratory influences were observed along the following gradient: healthy full-term newborns → preterm newborns → full-term newborns with pathology.

Effect of listening music (Rabindra Sangeet) on autonomic dysfunction in patients with generalized anxiety disorder: A power spectral analysis of heart rate variability

Background: Power spectral analysis of heart rate variability (HRV) is a complex method for assessing cardiac autonomic nerve function (CANF) in generalized anxiety disorder (GAD) patients which is a common mental disorder in the world. Recently, music therapy is used as an adjunct to pharmacotherapy in clinical psychiatry for GAD. Objective: To observe the effect of music therapy on CANF by power spectral analysis of HRV in GAD patients was designed. Methods: This prospective non randomized intervention study was done in 2019 on 60 newly diagnosed GAD patients aged 20- 40 years, both male and female. Among them 30 patients were under music therapy with listening of Raga Bhairabi based Rabindra sangeet for 3 months and 30 patients were without music therapy for three months. Age, sex and BMI matched healthy control were also enrolled. HRV of all GAD patients and control were recorded at baseline and after three months of follow up. HRV were recorded by Power Lab 8/35. For statistical analysis Bonferroni’s Post Hoc test and paired sample‘t’ test were done. Results: Total power, LF power, HF power, LF n.u, HF n.u and LF/HF and were significantly lower in all GAD patients compared to healthy control at baseline. After 3 months of music therapy, significant increment of Total power, HF power, HF n.u and significant decrement of LF n.u and LF/HF occurred whereas no change of these except HF n.u were noted in patients without music after 3 months. Moreover, after three months of music therapy, Total power, HF n.u, and LF/HF were almost same to control. Conclusion: So this study concluded that music therapy improve autonomic dysfunction in GAD patients and can be used as an adjunct to pharmacotherapy in clinical psychiatry for good cardiac health in GAD patients. J Bangladesh Soc Physiol 2022;17(2): 91-100

Влияние коморбидного метаболического синдрома на нарушения кардиореспираторной регуляции у больных нетяжелой внебольничной пневмонией

Community-acquired pneumonia (CAP) and metabolic syndrome (MS) are important independent medical and social problems. At the same time, the comorbid effect of MS on the course of CAP has not been sufficiently studied. The purpose — to evaluate the additional contribution of the metabolic syndrome (MS) to dysregulation of the cardiorespiratory system in patients with moderate severity community-acquired pneumonia (CAP). Material and methods. Four groups were examined: the first control group (CG) of 35 healthy individuals, the second control group CG + MS of 14 individuals with MS but without any acute disease; the group of 62 patients with CAP, and the group of 28 patients with CAP and comorbide MS (CAP+MS). To assess cardio-respiratory regulation, ECG and impedance pneumogram were synchronously recorded for 10 minutes. Time series of consecutive cardiointervals NN and respiratory intervals Ttot were formed from this recording. Heart rate variability (HRV) and respiratory rhythm variability (RRV) were evaluated by calculation of standard deviations (SDNN, TtotSD) and variation coefficients (CVNN, TtotCV). The spectral analysis of HRV was also performed with determination of the total spectral power Ptotal, spectral power in the intervals of 0.04–0.15 Hz (PLF) and 0.15–0.40 Hz (PHF). The data are presented as median and interquartile range Me (Q1; Q3). Results. In patients with CAP and comorbid MS, the most pronounced decrease in the variability of heart and respiratory rhythms was revealed, and it was more reliably characteristic of heart rate variability. The values of variability parameters in the CAP(1) and CAP + MS(1) groups were: SDNN — 31.7 (23.1; 43.3) and 15.6 (10.8; 20.0) ms, respectively, p < 0.001, CVNN — 3.9 (2.7; 5.0) and 2.2 (1.7; 2.8) %, p < 0.001, PLF 150.8 (73.6; 272.5) and 33.9 (15.3; 81.5) ms2, p < 0.001, PHF — 167.0 (52.5; 468.7) and 22.7 (10.5; 64.4) ms2, p < 0.001. The values of variability parameters in the CAP(2) and CAP + MS(2) groups were: SDNN — 40.7 (29.5; 62.6) and 22.4 (14.7; 33.9) ms, respectively, p < 0.001, CVNN — 4.7 (3.3; 6.9) and 3.0 (2.1; 4.2)%, p < 0.001, PLF 219.4 (119.6; 443.6) and 124.5 (30.4; 195.6) ms2, p = 0.001, PHF — 371.0 (93.4; 845.0) and 67.3 (27.8; 127.9) ms2, p < 0.001. Conclusions. The presence of comorbid MS significantly aggravates functional dysregulation of the cardiovascular and respiratory systems in patients with moderate CAP.

Influence of static and dynamic changes in body positions on functional changes of the cardiovascular system

The autonomic nervous system (ANS) plays an important role in the regulation of heart activity, breathing and blood pressure. Through changes in sympathetic and parasympathetic activity, it participates in the regulation, coordination and integration of internal organ function. The method of spectral analysis of heart rate variability (SAHRV) is used to examine the functional status of autonomic regulation of heart activity. During the examination, clino-ortho-clinostasis is used, which makes it possible to assess the reactivity of functional changes in the sympathetic and parasympathetic systems.We were therefore interested in what functional changes in the autonomic regulation of heart activity will occur during static and dynamic changes in the position of the body head down and up at angles of ± 45°.For the research, we used the method of spectral analysis of heart rate variability, supplemented by blood pressure measurement during the experiment. The experimental group included 24 healthy women aged 20-30. Before and after the experiment, a standard examination of the functional state of the autonomic nervous system was performed in the clino-ortho-clinostatic position.
 During the experimental sequence, changes in sympathetic, vagus, heart rate and blood pressure reactivity were monitored in the following positions:
 
 in an inclined position of the body with the head up – angle +45°
 in an inclined position of the body with the head down – angle -45°
 during dynamic changes in oblique body positions +-45°
 
 An auto-traction reclining couch was used for the investigation of oblique positions.
 The resultsDuring the application of oblique positions of the body, there are significant changes in the activity of the autonomic regulation of heart activity.In the head down position, there is an increased activation of the parasympathetic, a decrease in heart rate and an increase in systolic and diastolic pressure.During dynamic changes in body positions +- 45°, there is significant alternating activation of baroreflexes, modulated by sympathetic and vagal aktivity.
 ConclusionThe research study draws attention to the existence to multiple interconnections of regulatory mechanisms between the autonomic nervous system, cardiovascular and cardiorespiratory systems.

The peculiarities of changes in myocardial electrical activity and heart rate variability in patients with coronary artery disease depending on the stage of concomitant iron deficiency

The aim of the study: to assess changes in myocardial electrical activity and heart rate variability (HRV) in patients with coronary artery disease (CAD) depending on the stage of iron deficiency (ID) and identify their relationship with ferrokinetic parameters. Materials and methods. In total, 90 patients with CAD, stable angina II–III FC were examined (men – 35, women – 55, age – 69 (61; 72) years). The patients were divided into 4 groups: the 1st group (n = 16) consisted of patients with concomitant ID anemia (IDA) of mild and moderate severity, the 2nd (n = 15) – with latent ID, the 3rd (n = 14) – with functional ID, the 4th (n = 45) – patients with CAD without iron metabolism disorders. The HRV features during 24 hours, daytime and nighttime as well as their relationships with ferrokinetic and hematological parameters were analyzed. The data analysis was performed using Statistica 13.0. Results. CAD patients with concomitant IDA demonstrated a tendency to have a higher average daytime heart rate value (U = 14.0; p ≈ 0.08), a longer duration of tachycardia (U = 20.0; p ≈ 0.06), and a significantly greater number (2.4 times) of ventricular extrasystoles (VE) (U = 7.0; p < 0.05) compared to patients without iron metabolism disorders. There were no statistically significant differences in heart rate, episodes of tachycardia, and the number of arrhythmic events in CAD patients with different stages of ID. During the temporal analysis of HRV indicators, patients with different stages of concomitant ID demonstrated a decrease in overall HRV due to SDNN-index, rMSSD (%) and HRVT triangular index both in active and passive periods as compared to patients without iron metabolism disorders. Spectral analysis of HRV has revealed reduced parasympathetic activity of the autonomic nervous system due to HF indicator in patients of the 1st–3rd groups. The presence of concomitant IDA was characterized by maximum changes in HRV indicators and the predominance of central mechanisms of HRV regulation over autonomic ones, which was confirmed by a significant increase in the centralization index (IC) and stress index (SI). For CAD patients with concomitant IDA and latent ID, a number of relationships between ferrokinetic and HRV parameters was found. There were no statistically significant correlations between indicators of iron metabolism and HRV in patients with CAD and functional ID. Conclusions. The decrease in iron stores in the body due to its tissue and transport reserves is accompanied by changes in the myocardial electrical activity, a progressive reduction in heart rate variability, autonomic dysfunction towards a suppression of the parasympathetic domain activity, confirming the relevant correlations with the ferrokinetic parameters.

The effect of chronic exercise training and acute exercise on power spectral analysis of heart rate variability.

Moderate to vigorous physical activity performed regularly is cardioprotective and reduces all-cause mortality, concomitant with increased resting heart rate variability (HRV). However, there are contradictory reports regarding the effects of chronic and acute exercise on nocturnal HRV in those performing exercise well-beyond physical activity guidelines. Therefore, the purpose of this study was to compare the power spectral analysis components of HRV in middle-aged endurance athletes (EA) and recreationally active individuals (REC) and explore acute exercise effects in EA. A total of 119 EA (52, 49-57 years) and 32 REC (56, 52-60 years) were recruited to complete 24h Holter monitoring (GE SEER 1000) in the absence of exercise. Fifty one EA (52, 49-57 years) then underwent 24h Holter monitoring following an intense bout of endurance exercise. Power spectral HRV analysis was completed hourly and averaged to quantify morning (1000-1200h), evening (1900-2100h), and nocturnal (0200-0400h) HRV. EA had greater very low frequency (VLF) and low frequency (LF) (both p< 0.001) compared to REC. LF/high frequency (HF) was greater in EA at 0200-0400h (p=0.04). Among all participants, the change in HR and HF from 1000-1200 to 0200-0400h was negatively correlated (r=-0.47, p< 0.001). Following acute exercise in EA, only nocturnal HRV was assessed. VLF (p< 0.001) and HF (p=0.008) decreased, while LF/HF increased (p=0.02). These results suggest that in EA, both long-term and acute exercises increase nocturnal sympathovagal activity through an increase in LF and decrease in HF, respectively. Further work is required to understand the mechanism underlying reduced nocturnal HRV in middle-aged EA and the long-term health implications.

Aerobic Physical Exercise is Essential for Cardiac Autonomic Regulation in Hypertensive Patients Undergoing Chronic Treatment with Renin-Angiotensin System Inhibitors.

Hypertension treatment with renin-angiotensin system inhibitors (RASi) presents contradictions about the recovery of damage in cardiovascular autonomic modulation characterized by reduced heart rate variability (HRV) and increased blood pressure variability (BPV). Conversely, the association of RASi with physical training can influence achievements in cardiovascular autonomic modulation. To investigate the effects of aerobic physical training on hemodynamics and cardiovascular autonomic modulation in hypertensive volunteers untreated and treated with RASi. A non-randomized controlled trial in which 54 men ( 40-60 years old) with a history of hypertension for >2 years were allocated in accordance with their characteristics into three groups: untreated (Control; n=16), treated with type 1 angiotensin II (AT1) receptor blocker (losartan; n=21), and treated with angiotensin-converting enzyme inhibitor (enalapril; n=17). All participants underwent hemodynamic, metabolic, and cardiovascular autonomic evaluation using baroreflex sensitivity (BRS) and spectral analysis of HRV and BPV, before and after 16 weeks of supervised aerobic physical training. The volunteers treated with RASi had lower BPV and HRV, both in the supine position and in the tilt test, with the losartan group having the lowest values. Aerobic physical training increased HRV and BRS in all groups. However, the association of enalapril with physical training appears to be more prominent. Long-term treatment with enalapril and losartan may harm the autonomic modulation of HRV and BRS. Aerobic physical training is essential to promote positive adjustments in the autonomic modulation of HRV and BRS in hypertensive patients treated with RASi, especially with enalapril.

Effects of the beta-stimulating training in recovery of adaptive reserves in athletes of different sports

To identify effects of the beta-stimulating training in recovery of adaptive reserves in athletes of different sports. The study included young male athletes aged 18-22 years (n=1020), distributed according to the type of sports: group 1 - cyclic sports (n=387); group 2 - speed-strength sports (n=255); group 3 - single combat (n=31); group 4 - team sports (n=173); group 5 - complex-coordination sports (n=174). The main objective of the beta-stimulating training was to select a strategy to raise the beta rhythm level while muscles were relaxed. For each group, we identified training efficiency periods according to the lowest value of the attention index (θ/β, c.u.), then we examined distribution of brain rhythms (α, %; β, %; θ, %) according to EEG. The level of adaptive reserves was identified according to the heart rate variability (HRV) spectral analysis («VNS-Spektr», Neurosoft, Ivanovo). We identified following periods of the beta-stimulating training efficiency according to the attention index (θ/β, c.u.): group 1 - 10th session (game variant); group 2 - 5th session (graphic and game variants); group 3 - 1st and 10th sessions (game variant), 5th session (graphic variant); group 4 (game variant) - 1st, 5th and 10th sessions; group 5 (game variant) - 5th and 10th sessions. The efficiency periods in the observed groups were accompanied by the following distribution of rhythms in the EEG structure: β-rhythm - 45-60%; θ-rhythm - 20-35%, α-rhythm - 19-25%. During these periods, wave structure of the heart rhythm also changed: the activity of VLF waves increased (%); the proportion of HF waves decreased in the range of 23.3-31.59% in the groups 1, 2 and 3; the share of HF waves increased in the range of 32.3-39.8% in the group 4 at the 1st session and in the group 5 at the 10th session. The values of total power (TP, ms2) reduce at the 10th session in the groups 1, 3 and 4 and at the 5th session in the group 5. The vagosympathetic balance coefficient (LF/HF, c.u.) in the studied groups corresponds to the range of normal values; the values increased in the group 2 at the 5th session, in the groups 3 and 4 - at the 5th and 10th sessions, in the 5th group - at the 5th session. The index decreased in the groups 3 and 4 at the 1st session. The index was stable in the groups 1 and 5 at the 10th session of the training. Periods of the beta-stimulating training efficiency associated with the improvement of attention according to the lowest values of θ/β (c.u.) are accompanied by changes in the modulation of the structure of brain rhythms and the wave structure of heart rate variability, optimizing the psychophysiological state of athletes depending on the type of sport, the number of sessions completed and the session variants chosen.

Особенности желудочковой экстрасистолии на фоне коморбидной патологии у юных спортсменов

Aim: to assess the role of autonomic disorders and undifferentiated connective tissue dysplasia (UCTD) of the heart in children with ventricular extrasystoles (VE) engaged in sports. Patients and Methods: the study included 52 athlete boys with newly diagnosed cardiac arrhythmia in the form of ventricular extrasystoles. The study group (n=34) consisted of children with moderate VE severity co-existing with asympaticotonic type of autonomic dysfunction syndrome (ADS) amid undifferentiated connective tissue dysplasia mostly affecting the heart (UCTDH). The study group was split into two subgroups: subgroup 1 (n=11) – children with monotopic VE persisting at load and subgroup 2 (n=23) – children with occasionally appearing VE which reduced in the vertical position and/or at load. The control group (n=18) consisted of children with moderate VE amid UCTDH without ADS manifestations. A comprehensive clinical and laboratory assessment was performed in all patients. Results: on Holter monitoring (HM), in patients of the study group, subgroup 1, a sinus rhythm was recorded with the presence of 9,000- 15,000 VE per day (single or paired). The power spectral analysis of heart rate variability (HRV) in the subgroup 1 children demonstrated that in most cases (10 (90.9%)) there were low levels of the total power (TP) (р&lt;0.05) and high values of the high-frequency component (HF) (p&lt;0.05) as compared to those in the control group children. Also, a significant decrease in creatine phosphokinase-MB activity in the blood serum was found in children of the study group, subgroup 1, as compared to the reference values (р&lt;0.05). The VE development in the study group, subgroup1, children was caused by the combined exposure to sport loads and the autonomic control of cardiovascular function amid UCTDH. In the study group, subgroup 2, children the laboratory testing did not demonstrate any statistically significant changes in creatine phosphokinase-MB activity in the blood serum as compared to the reference values (р&gt;0.05). On HM, in most of the subgroup 2 children, a sinus rhythm was recorded with the presence of 6,000-9,000 VE per day. The changes in HRV parameters and their spectrogram in 19 (82.6%) cases were common for asympaticotonic type. As compared to the values in the control group children, TP was slightly lower (р&gt;0.05) along with a high HF level (р&gt;0.05). A half of the control group children had a moderate increase in creatine phosphokinase-MB activity in the blood serum (р&lt;0.05), while in other cases its values did not differ considerably from the normal range. On HM, in most cases a normal sinus rhythm with usually single EV, 300-5,000 per day, was recorded. The main measurements of the power spectral analysis of HRV and spectrogram indicators suggested that children of this group had sufficient body energy supply. The presence of VE in the control group children was associated with the impact of sport loads on the heart with dysplasia. Conclusion: the authors have distinguished the clinical variants of heart rhythm disorders in young athletes with different levels of body energy supply, VE patterns, etc. In young athletes, ventricular extrasystoles are characterized by a persisting occurrence in cases with asympaticotonic type of autonomic disorders amid UCTDH. They are associated with a decrease in energy supply of the body, in particular, the myocardial muscle. Occasionally occurring VE were recorded in athletes without significant disturbances in energy supply. KEYWORDS: ventricular extrasystoles, autonomic dysfunction syndrome, undifferentiated connective tissue dysplasia of the heart, energy supply, athletes. FOR CITATION: Cherkasov N.S., Doronina T.N., Prakhov A.V., Semenova I.A. Characteristics of ventricular extrasystoles co-occurring with comorbidities in young athletes. Russian Journal of Woman and Child Health. 2023;6(1):45–49 (in Russ.). DOI: 10.32364/2618-8430-2023-6-1-45-49.

Autonomic function predicts cognitive decline in mild cognitive impairment: Evidence from power spectral analysis of heart rate variability in a longitudinal study.

BackgroundDespite the emerging clinical relevance of heart rate variability (HRV) as a potential biomarker of cognitive decline and as a candidate target for intervention, there is a dearth of research on the prospective relationship between HRV and cognitive change. In particular, no study has addressed this issue in subjects with a diagnosis of cognitive status including cognitive impairment.ObjectiveTo investigate HRV as a predictor of cognitive decline in subjects with normal cognition (NC) or Mild Cognitive Impairment (MCI). Specifically, we tested the literature-based hypothesis that the HRV response to different physical challenges would predict decline in different cognitive domains.MethodsThis longitudinal study represents the approximately 3-year follow-up of a previous cross-sectional study enrolling 80 older outpatients (aged ≥ 65). At baseline, power spectral analysis of HRV was performed on five-minute electrocardiographic recordings at rest and during a sympathetic (active standing) and a parasympathetic (paced breathing) challenge. We focused on normalized HRV measures [normalized low frequency power (LFn) and the low frequency to high frequency power ratio (LF/HF)] and on their dynamic response from rest to challenge (Δ HRV). Extensive neuropsychological testing was used to diagnose cognitive status at baseline and to evaluate cognitive change over the follow-up via annualized changes in cognitive Z-scores. The association between Δ HRV and cognitive change was explored by means of linear regression, unadjusted and adjusted for potential confounders.ResultsIn subjects diagnosed with MCI at baseline a greater response to a sympathetic challenge predicted a greater decline in episodic memory [adjusted model: Δ LFn, standardized regression coefficient (β) = −0.528, p = 0.019; Δ LF/HF, β = −0.643, p = 0.001] whereas a greater response to a parasympathetic challenge predicted a lesser decline in executive functioning (adjusted model: Δ LFn, β = −0.716, p < 0.001; Δ LF/HF, β = −0.935, p < 0.001).ConclusionOur findings provide novel insight into the link between HRV and cognition in MCI. They contribute to a better understanding of the heart-brain connection, but will require replication in larger cohorts.

Complementary Role of Combined Indirect and Direct Cardiac Sympathetic (Hyper)Activity Assessment in Patients with Heart Failure by Spectral Analysis of Heart Rate Variability and Nuclear Imaging: Possible Application in the Evaluation of Exercise Training Effects.

In chronic heart failure (CHF), abnormalities in cardiac autonomic control, characterized by sympathetic overactivity, contribute to the progression of the disease and are associated with an unfavorable prognosis. Assessing cardiac autonomic status is clinically important in the management of patients with CHF. To this aim, heart rate variability (HRV) analysis has been extensively used as a non-invasive tool for assessing cardiac autonomic regulation, and has been shown to predict the clinical outcome in patients with CHF. Adrenergic nerve activity has also been estimated using iodine-123 (I-123) metaiodobenzylguanidine (MIBG), a noradrenaline analogue. MIBG is an analogue of norepinephrine sharing the same cellular mechanism of uptake, storage, and release in presynaptic sympathetic neurons. As an innervation tracer, 123I-MIBG allows for the evaluation of cardiac sympathetic neuronal function. Cardiac MIBG imaging has also been reported to predict a poor clinical outcome in CHF. MIBG provides direct information on the function of the presynaptic sympathetic nerve endings, whereas HRV, which depends on postsynaptic signal transduction, reflects the end-organ response of the sinus node. The aim of this brief review is to provide the reader with some basic concepts regarding the spectral analysis of HRV and MIBG, highlighting what is known about their respective roles in detecting cardiac sympathetic hyperactivity in CHF and, in perspective, their possible combined use in assessing non-pharmacological treatments in patients with CHF and reduced ejection fraction, with a particular focus on the effects of exercise training.

Heart Rate Variability Analysis as a Patient Investigation Won’t Be an Ideal Test for Assessing Autonomic Dysfunctions

Autonomic dysfunctions have been associated with many clinical disorders. Dysregulation of autonomic functions is reported to be involved in etiopathogenesis of cardio-metabolic diseases such as diabetes, hypertension, heart diseases and so on. Therefore, recently autonomic function tests (AFTs) have become part of routine patient investigations in medical practice. Standard autonomic assessments include conventional AFTs, spectral analysis of heart rate variability (HRV) and blood pressure variability (BPV). Recently, HRV analysis has become a more popular test in investigating autonomic disorders. Nevertheless, an investigator should be aware of the limitations of HRV analysis, especially that of shortterm HRV, especially when it is done as a single investigation of the AFT. Therefore, in this editorial we analyse the merits and demerits of spectral analysis of HRV, used for patients’ investigations in clinical practice.

The Usefulness of Heart Rate Variability Spectral Analysis in Detecting Covert Atrial Fibrillation among Patients with Cryptogenic Stroke

The Usefulness of Heart Rate Variability Spectral Analysis in Detecting Covert Atrial Fibrillation among Patients with Cryptogenic Stroke

Obesity and heart rate variability: A cross-sectional study in obese young adults

CONTEXT: Obesity is one of the important causative factors for multiple co-morbid conditions that can lead to metabolic and cardiac disorders. Many research studies indicate the association of obesity and sudden cardiac deaths.AIMS: This study was aimed to evaluate the cardiac autonomic nervous system activity, given by the changes in heart rate variability (HRV) in healthy obese young adults.SETTINGS AND DESIGN: This cross-sectional study included thirty obese young adult males of 18–25 years and 30 age-matched healthy adult males. Power spectral analysis of HRV was used to determine the autonomic imbalance.SUBJECTS AND METHODS: HRV was performed using HRV software (Lab Chart 7). Numerical data of absolute values of low frequency (LF) and high frequency (HF) (in ms2), normalized units of LF and HF (in nu) and LF/HF ratio were expressed as mean ± standard deviation and analyzed.RESULTS: On statistical analysis, it was found that HF in normalized units was significantly low in obese young adults compared to age-matched controls. LF (nu) and LF/HF ratio were higher in obese subjects compared to controls, though they were not statistically significant. Although there was negative correlation between HRV parameters and body mass index in obese individuals, it was not significant.CONCLUSIONS: These results suggest that obese young adults present with changes in the autonomic nervous system, characterized by decrease in parasympathetic activity.

Heart rate variability modifications in response to different types of exercise training in athletes.

Spectral analysis of heart rate variability (HRV) is a long-standing technique to indirectly assess neural cardiac regulation. This article specifically addressed how spectral analysis of HRV could help to understand neural cardiovascular adaptations to long-term exercise training; and inform us on training status in athletes. We reviewed literature searching for articles investigating resting cardiovascular adaptations to long-term exercise training through spectral analysis of HRV in athletes, from amateur to world class categories, practicing different sport disciplines, and focusing, in particular, on a series of work performed over time in our laboratory, which may highlight how different types of exercise training differently affect neural cardiac regulation. Spectral analysis of HRV has been shown its capability of detecting different adaptational changes in cardiac autonomic nervous system (ANS) regulation attending physical training in athletes of different sport disciplines. Studies showed that spectral analysis of HRV provide results that are sport-dependent and differ at individual level. ANS adaptations to exercise training are presented and discussed. Reported studies indicate that spectral analysis of HRV is an effective tool to monitor and optimize the training process and to predict athletic achievements in competitions. Cardiac ANS adaptations are strongly dependant on the type of training being performed. The individual nature of cardiac ANS adaptations should be considered to properly interpret the observed findings.

Comparison of the effects of new anti-seizure drugs (ASDS) on cardiac autonomic control in patients with temporal lobe epilepsy (TLE)

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy in adulthood. Temporal lobe plays a central role in the regulation of cardio-autonomic functions (CAF) which can be also influenced by several anti-seizure therapies. The spectral analysis of the Heart Rate Variability (HRV) represents a useful tool for the evaluation of CAF. The aim of this study is to assess, using the spectral analysis of HRV, new anti-seizure medication (ASMs) - Perampanel (PER), Lacosamide (LCS), Eslicarbazepine (ECB) and Brivaracetam (BRV) - effects on CAF in patients with TLE.

Alternations in the Cardiovascular Autonomic Regulation and Growth Factors in Autism.

Autism spectrum disorder (ASD) represents a serious neurodevelopmental disorder associated with autonomic nervous system dysregulation. The aim was to study complex cardiovascular autonomic regulation using heart rate variability (HRV) and systolic blood pressure variability (SBPV) linear/non-linear analysis at rest and during orthostasis, and to assess plasma levels of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) in autistic children. Twenty-five ASD boys and 25 age and gender-matched children at the age 7-15 years were examined. After venous blood taking, continuous ECG and blood pressure biosignals were recorded at rest and during orthostasis. Evaluated parameters: RR intervals, high- and low-frequency band of HRV spectral analysis (HF-HRV, LF-HRV), symbolic dynamics parameters 0V%, 1V%, 2LV%, 2UV%, low- and high-frequency band of SBPV (LF-SBPV, HF-SBPV), systolic, diastolic, mean blood pressure, EGF, VEGF plasma levels. RR intervals were significantly shortened and the HF-HRV, LF-SBPV, HF-SBPV parameters were significantly lower at rest, the HF-HRV and LF-SBPV remained lower during orthostasis in autistic children compared to controls (p<0.05). EGF plasma levels were significantly lower in ASD compared to controls (p=0.046). No significant differences were found in remaining parameters. Our study revealed tachycardia, cardiovagal underactivity, and blunted sympathetic vasomotor regulation at rest and during orthostasis in autistic children. Additionally, complex heart rate dynamics are similar in autistic children than controls. Furthermore, EGF was reduced in autistic children without significant correlations with any autonomic parameters. We suggest that the abnormal complex cardiovascular reflex control could contribute to understanding the pathway linking autonomic features and autism.

History of the arterial tonometer and the “Pranayama” gadget

An arterial tonometer that allows you to determine the pressurein the shoulder from the pulse wave of the radial artery withoutsqueezing the vessels with a cuff, today remains an unattainablegoal of many researchers due to the lack of suitable pulse wavesensors (PV). The article describes a mobile medicine device,which is a kind of “smart watch” with its original function of ahuman pulse wave analyzer. This function has become possibledue to an introduction of a matrix fiber-optic sensor (MFOS)developed by a team of Russian scientists at the A. A. BlagonravovIMASH at the Russian Academy of Sciences. Features ofthe device that distinguish it from existing analogues are givenbelow:1) Capability to determine blood pressure with medical accuracywithout squeezing blood vessels with a cuff,2) Capability to diagnose the cardiovascular system and assessits condition taking into account the age of a person,3) Capability to diagnose all human organ systems using spectralanalysis of heart rate variability,4) Capability to determine the code (modulation frequency)corresponding to the established disease after the diagnosisis established using this gadget, and to carry out targeted deliveryof an increased amount of blood to the affected organ,5) Capability to perform high-quality monitoring of blood pressure(over time).After diagnosis, the gadget determines the code (modulationfrequency) corresponding to the established disease and promotestargeted delivery of an increased amount of blood to theaffected organ. Treatment is carried out by organizing a certainrespiratory rate, which, in turn, generates certain modulationsof the heart rate. As a result, the affected organ receives anadditional amount of blood and recovers.

Spectral decomposition of heart rate variability using generalized harmonic analysis

In this paper, a method for decomposing harmonics in the spectrum of heart rate variability (HRV) using generalized harmonic analysis (GHA) is introduced. First, a simulated RR interval signal generated by an integral pulse frequency modulation model was decomposed spectra by GHA, Pisarenko harmonic decomposition (PHD), and autoregressive (AR) spectral decomposition model. The spectral profiles were obtained by the GHA, PHD, and AR methods for various numbers of extracted sinusoids and model orders from 1 to 48. The spectral profiles of GHA were the most stable. Of the power values of the sinusoids extracted by each method, it was clear that the power values estimated by GHA were approximately equal to the mean square value and closer than that obtained using the PHD or a fast Fourier transform (FFT). Second, a comparison of the power of the low-frequency (LF) and high-frequency (HF) band components reveals that the values obtained by GHA are similar to those obtained by FFT for the analysis using a real ECG signal. Third, Bland-Altman analysis reveals that LF and HF band power value calculated by the GHA are compatible with ones by the Lomb-Scargle periodogram using MIT-BIH normal sinus rhythm database from short term recordings of 30 min. These results suggest that GHA is a useful tool for calculating the power of a component in the spectral analysis of HRV. The limitations of spectral decomposition by GHA are still discussed.

Reduced Cell Excitability of Cardiac Postganglionic Parasympathetic Neurons Correlates With Myocardial Infarction-Induced Fatal Ventricular Arrhythmias in Type 2 Diabetes Mellitus

ObjectiveWithdrawal of cardiac vagal activity is considered as one of the important triggers for acute myocardial infarction (MI)-induced ventricular arrhythmias in type 2 diabetes mellitus (T2DM). Our previous study demonstrated that cell excitability of cardiac parasympathetic postganglionic (CPP) neurons was reduced in T2DM rats. This study investigated whether cell excitability of CPP neurons is associated with cardiac vagal activity and MI-induced ventricular arrhythmias in T2DM rats.MethodsRat T2DM was induced by a high-fat diet plus streptozotocin injection. MI-evoked ventricular arrhythmia was achieved by surgical ligation of the left anterior descending coronary artery. Twenty-four-hour, continuous ECG recording was used to quantify ventricular arrhythmic events and heart rate variability (HRV) in conscious rats. The power spectral analysis of HRV was used to evaluate autonomic function. Cell excitability of CPP neurons was measured by the whole-cell patch-clamp technique.ResultsTwenty-four-hour ECG data demonstrated that MI-evoked fatal ventricular arrhythmias are more severe in T2DM rats than that in sham rats. In addition, the Kaplan-Meier analysis demonstrated that the survival rate over 2 weeks after MI is significantly lower in T2DM rats (15% in T2DM+MI) compared to sham rats (75% in sham+MI). The susceptibility to ventricular tachyarrhythmia elicited by programmed electrical stimulation was higher in anesthetized T2DM+MI rats than that in rats with MI or T2DM alone (7.0 ± 0.58 in T2DM+MI group vs. 3.5 ± 0.76 in sham+MI). Moreover, as an index for vagal control of ventricular function, changes of left ventricular systolic pressure (LVSP) and the maximum rate of increase of left ventricular pressure (LV dP/dtmax) in response to vagal efferent nerve stimulation were blunted in T2DM rats. Furthermore, T2DM increased heterogeneity of ventricular electrical activities and reduced cardiac parasympathetic activity and cell excitability of CPP neurons (current threshold-inducing action potentials being 62 ± 3.3 pA in T2DM rats without MI vs. 27 ± 1.9 pA in sham rats without MI). However, MI did not alter vagal control of the ventricular function and CPP neuronal excitability, although it also induced cardiac autonomic dysfunction and enhanced heterogeneity of ventricular electrical activities.ConclusionThe reduction of CPP neuron excitability is involved in decreased cardiac vagal function, including cardiac parasympathetic activity and vagal control of ventricular function, which is associated with MI-induced high mortality and malignant ventricular arrhythmias in T2DM.