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Delliaux S, Ichinose M, Watanabe K, Fujii N, Nishiyasu T. Muscle metaboreflex activation during hypercapnia modifies nonlinear heart rhythm dynamics, increasing the complexity of the sinus node autonomic regulation in humans. Pflugers Arch 2023; 475:527-539. [PMID: 36645512 DOI: 10.1007/s00424-022-02780-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 01/17/2023]
Abstract
Muscle metaboreflex activation during hypercapnia leads to enhanced pressive effects that are poorly understood while autonomic responses including baroreflex function are not documented. Thus, we assessed heart rate variability (HRV) that is partly due to autonomic influences on sinus node with linear tools (spectral analysis of instantaneous heart period), baroreflex set point and sensitivity with the heart period-arterial pressure transfer function and sequences methods, and system coupling through the complexity of RR interval dynamics with nonlinear tools (Poincaré plots and approximate entropy (ApEn)). We studied ten healthy young men at rest and then during muscle metaboreflex activation (MMA, postexercise muscle ischemia) and hypercapnia (HCA, PetCO2 = + 10 mmHg from baseline) separately and combined (MMA + HCA). The strongest pressive responses were observed during MMA + HCA, while baroreflex sensitivity was similarly lowered in the three experimental conditions. HRV was significantly different in MMA + HCA compared to MMA and HCA separately, with the lowest total power spectrum (p < 0.05), including very low frequency (p < 0.05), low frequency (p < 0.05), and high frequency (tendency) power spectra decreases, and the lowest Poincaré plot short-term variability index (SD1): SD1 = 36.2 ms (MMA + HCA) vs. SD1 = 43.1 ms (MMA, p < 0.05) and SD1 = 46.1 ms (HCA, p < 0.05). Moreover, RR interval dynamic complexity was significantly increased only in the MMA + HCA condition (ApEn increased from 1.04 ± 0.04, 1.07 ± 0.02, and 1.05 ± 0.03 to 1.10 ± 0.03, 1.13 ± 0.04, and 1.17 ± 0.03 in MMA, HCA, and MMA + HCA conditions, respectively; p < 0.01). These results suggest that in healthy young men, muscle metaboreflex activation during hypercapnia leads to interactions that reduce parasympathetic influence on the sinus node activity but complexify its dynamics.
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Affiliation(s)
- Stephane Delliaux
- Aix Marseille Univ, INSERM, INRAE, C2VN, Marseille, France.
- Assistance Publique - Hôpitaux de Marseille, APHM, Hôpital Nord, Pôle Cardiovasculaire et Thoracique, Laboratoire de Physiologie Respiratoire - Explorations à l'Exercice, Marseille, France.
- Laboratory of Physiology - Circulation, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
- Japan Society for the Promotion of Science, Tokyo, Japan.
| | - Masashi Ichinose
- Laboratory of Physiology - Circulation, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- School of Business and Administration, Meiji University, Tokyo, Japan
| | - Kazuhito Watanabe
- Laboratory of Physiology - Circulation, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Naoto Fujii
- Laboratory of Physiology - Circulation, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Takeshi Nishiyasu
- Laboratory of Physiology - Circulation, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
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Azami H, Sanei S, Rajji TK. Ensemble entropy: A low bias approach for data analysis. Knowl Based Syst 2022. [DOI: 10.1016/j.knosys.2022.109876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Heart Rate Variability as a Potential Indicator of Cancer Pain in a Mouse Model of Peritoneal Metastasis. SENSORS 2022; 22:s22062152. [PMID: 35336325 PMCID: PMC8955674 DOI: 10.3390/s22062152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/05/2022] [Accepted: 03/09/2022] [Indexed: 01/27/2023]
Abstract
Heart rate variability (HRV) is closely related to changes in the autonomic nervous system (ANS) associated with stress and pain. In this study, we investigated whether HRV could be used to assess cancer pain in mice with peritoneal metastases. At 12 days after cancer induction, positive indicators of pain such as physiological characteristics, appearance, posture, and activity were observed, and time- and frequency-domain HRV parameters such as mean R-R interval, square root of the mean squared differences of successive R-R intervals, and percentage of successive R-R interval differences greater than 5 ms, low frequency (LF), high frequency (HF), and ratio of LF and HF power, were found to be significantly decreased. These parameters returned to normal after analgesic administration. Our results indicate that overall ANS activity was decreased by cancer pain and that HRV could be a useful tool for assessing pain.
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Platiša MM, Radovanović NN, Kalauzi A, Milašinović G, Pavlović SU. Multiscale Entropy Analysis: Application to Cardio-Respiratory Coupling. ENTROPY 2020; 22:e22091042. [PMID: 33286811 PMCID: PMC7597100 DOI: 10.3390/e22091042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 07/30/2020] [Accepted: 08/14/2020] [Indexed: 02/07/2023]
Abstract
It is known that in pathological conditions, physiological systems develop changes in the multiscale properties of physiological signals. However, in real life, little is known about how changes in the function of one of the two coupled physiological systems induce changes in function of the other one, especially on their multiscale behavior. Hence, in this work we aimed to examine the complexity of cardio-respiratory coupled systems control using multiscale entropy (MSE) analysis of cardiac intervals MSE (RR), respiratory time series MSE (Resp), and synchrony of these rhythms by cross multiscale entropy (CMSE) analysis, in the heart failure (HF) patients and healthy subjects. We analyzed 20 min of synchronously recorded RR intervals and respiratory signal during relaxation in the supine position in 42 heart failure patients and 14 control healthy subjects. Heart failure group was divided into three subgroups, according to the RR interval time series characteristics (atrial fibrillation (HFAF), sinus rhythm (HFSin), and sinus rhythm with ventricular extrasystoles (HFVES)). Compared with healthy control subjects, alterations in respiratory signal properties were observed in patients from the HFSin and HFVES groups. Further, mean MSE curves of RR intervals and respiratory signal were not statistically different only in the HFSin group (p = 0.43). The level of synchrony between these time series was significantly higher in HFSin and HFVES patients than in control subjects and HFAF patients (p < 0.01). In conclusion, depending on the specific pathologies, primary alterations in the regularity of cardiac rhythm resulted in changes in the regularity of the respiratory rhythm, as well as in the level of their asynchrony.
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Affiliation(s)
- Mirjana M. Platiša
- Institute of Biophysics, Faculty of Medicine, University of Belgrade, KCS, PO Box 22, 11129 Belgrade, Serbia
- Correspondence: ; Tel.: +381-11-360-7158; Fax: +381-11-360-7061
| | - Nikola N. Radovanović
- Pacemaker Center, Clinical Center of Serbia, 11000 Belgrade, Serbia; (N.N.R.); (G.M.); (S.U.P.)
| | - Aleksandar Kalauzi
- Department for Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, 11000 Belgrade, Serbia;
| | - Goran Milašinović
- Pacemaker Center, Clinical Center of Serbia, 11000 Belgrade, Serbia; (N.N.R.); (G.M.); (S.U.P.)
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Siniša U. Pavlović
- Pacemaker Center, Clinical Center of Serbia, 11000 Belgrade, Serbia; (N.N.R.); (G.M.); (S.U.P.)
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
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Horn MA, Bode EF, Borland SJ, Kirkwood GJ, Briston SJ, Richards MA, Dibb KM, Trafford AW. Temporal Development of Autonomic Dysfunction in Heart Failure: Effects of Age in an Ovine Rapid-pacing Model. J Gerontol A Biol Sci Med Sci 2016; 71:1544-1552. [PMID: 26707382 PMCID: PMC5106849 DOI: 10.1093/gerona/glv217] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 11/09/2015] [Indexed: 01/19/2023] Open
Abstract
Heart failure (HF) is predominantly a disease of older adults and characterized by extensive sympatho-vagal imbalance leading to impaired reflex control of heart rate (HR). However, whether aging influences the development or extent of the autonomic imbalance in HF remains unclear. To address this, we used an ovine model of aging with tachypacing-induced HF to determine whether aging affects the chronotropic and inotropic responses to autonomic stimulation and reduction in heart rate variability (HRV) in HF. We find that aging is associated with increased cardiac dimensions and reduced contractility before the onset of tachypacing, and these differences persist in HF. Additionally, the chronotropic response to β-adrenergic stimulation was markedly attenuated in HF, and this occurred more rapidly in aged animals. By measuring HR during sequential autonomic blockade, our data are consistent with a reduced parasympathetic control of resting HR in aging, with young HF animals having an attenuated sympathetic influence on HR. Time-domain analyses of HR show a reduction in HRV in both young and aged failing animals, although HRV is lowest in aged HF. In conclusion, aging is associated with altered autonomic control and β-adrenergic responsiveness of HR, and these are exacerbated with the development of HF.
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Affiliation(s)
- Margaux A Horn
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre
| | - Elizabeth F Bode
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre
| | | | - Graeme J Kirkwood
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre
| | - Sarah J Briston
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre
| | - Mark A Richards
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre.
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Yaniv Y, Lyashkov AE, Lakatta EG. Impaired signaling intrinsic to sinoatrial node pacemaker cells affects heart rate variability during cardiac disease. ACTA ACUST UNITED AC 2014; 4. [PMID: 26251764 DOI: 10.4172/2167-0870.1000152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The normal heart beat intervals are neither strictly stationary nor completely random, and continuously shift from one period to another. Decoding the ECG identifies this "hidden" information that imparts inherent complexity to the heart-beating interval time series. Loss of this complexity in cardiovascular disease is manifested as a reduction in heart rate variability (HRV) and this reduction correlates with an increase in both morbidity and mortality. Because HRV measurements are noninvasive and easy to perform, they have emerged as an important tool in cardiology. However, the identities of specific mechanisms that underline the changes in HRV that occur in cardiovascular diseases remain largely unknown. Changes in HRV have mainly been interpreted on a neural basis, ie due to changes in autonomic impulses to the heart: sympathetic activity decreases both the average heart beat interval and HRV, and parasympathetic activity increases both. It has now become clear, however, that the heart rate and HRV are also determined by intrinsic properties of the pacemaker cells that comprise the sinoatrial node, and the responses of these properties to autonomic receptor stimulation. Here we review how changes in the properties of coupled-clock mechanisms intrinsic to pacemaker cells that comprise the sinoatrial node and their impaired response to autonomic receptor stimulation are implicated in the changes of HRV observed in heart diseases.
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Affiliation(s)
- Yael Yaniv
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Alexey E Lyashkov
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, 733 North Broadway, Baltimore, Maryland, USA
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, Biomedical Research Center, Intramural Research Program, National Institute on Aging, NIH, Baltimore, Maryland, USA
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Molina-Picó A, Cuesta-Frau D, Aboy M, Crespo C, Miró-Martínez P, Oltra-Crespo S. Comparative study of approximate entropy and sample entropy robustness to spikes. Artif Intell Med 2011; 53:97-106. [PMID: 21835600 DOI: 10.1016/j.artmed.2011.06.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 05/11/2011] [Accepted: 06/18/2011] [Indexed: 11/17/2022]
Abstract
OBJECTIVE There is an ongoing research effort devoted to characterize the signal regularity metrics approximate entropy (ApEn) and sample entropy (SampEn) in order to better interpret their results in the context of biomedical signal analysis. Along with this line, this paper addresses the influence of abnormal spikes (impulses) on ApEn and SampEn measurements. METHODS A set of test signals consisting of generic synthetic signals, simulated biomedical signals, and real RR records was created. These test signals were corrupted by randomly generated spikes. ApEn and SampEn were computed for all the signals under different spike probabilities and for 100 realizations. RESULTS The effect of the presence of spikes on ApEn and SampEn is different for test signals with narrowband line spectra and test signals that are better modeled as broadband random processes. In the first case, the presence of extrinsic spikes in the signal results in an ApEn and SampEn increase. In the second case, it results in an entropy decrease. For real RR records, the presence of spikes, often due to QRS detection errors, also results in an entropy decrease. CONCLUSIONS Our findings demonstrate that both ApEn and SampEn are very sensitive to the presence of spikes. Abnormal spikes should be removed, if possible, from signals before computing ApEn or SampEn. Otherwise, the results can lead to misunderstandings or misclassification of the signal regularity.
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Affiliation(s)
- Antonio Molina-Picó
- Technological Institute of Informatics, Polytechnic University of Valencia, Alcoi Campus, Plaza Ferrandiz y Carbonell, Spain.
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Alcaraz R, Rieta J. A review on sample entropy applications for the non-invasive analysis of atrial fibrillation electrocardiograms. Biomed Signal Process Control 2010. [DOI: 10.1016/j.bspc.2009.11.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Almoznino-Sarafian D, Sarafian G, Zyssman I, Shteinshnaider M, Tzur I, Kaplan BZ, Berman S, Cohen N, Gorelik O. Application of HRV-CD for estimation of life expectancy in various clinical disorders. Eur J Intern Med 2009; 20:779-83. [PMID: 19892308 DOI: 10.1016/j.ejim.2009.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 08/05/2009] [Accepted: 08/21/2009] [Indexed: 01/11/2023]
Abstract
BACKGROUND Low heart rate variability (HRV) was found in various medical conditions including heart failure and acute myocardial infarction. Decreased HRV in these conditions predicted poor prognosis. METHODS HRV was estimated in 133 unselected inpatients with relevant clinical bedside conditions by non-linear analysis derived from chaos theory, which calculates the correlation dimension (CD) of the cardiac electrophysiologic system (HRV-CD). RESULTS Mean HRV-CD in the entire group was 3.75+/-0.45. Heart failure, coronary artery disease, cardiac arrhythmia, low serum potassium, renal dysfunction, and diabetes mellitus were significantly associated with reduced HRV-CD compared to their counterparts [3.6 vs. 3.9 (P<.001), 3.65 vs. 3.87 (P=.005), 3.58 vs. 3.8 (P=.01), 3.38 vs. 3.81 (P=.02), 3.59 vs. 3.8 (P=.04), and 3.66 vs. 3.82 (P=.04), respectively]. Stepwise logistic regression showed heart failure to be the condition most significantly associated with low HRV-CD (odds ratio 4.2, 95% confidence interval 1.90-9.28, P<.001). In the entire group, decreased HRV-CD (< or =3.75 vs. >3.75) was associated with lower survival (P=.01). Mortality of diabetic patients with HRV-CD < or =3.75 exceeded the mortality in patients with HRV-CD >3.75 (P=.02). Heart failure, renal dysfunction or age over 70 combined with HRV-CD < or =3.75 also appeared to be associated with augmented mortality. CONCLUSIONS Diminished HRV-CD is associated with heart failure, coronary artery disease, cardiac arrhythmia, renal dysfunction, diabetes mellitus and low serum potassium. Among the latter, heart failure is most significantly associated with decreased HRV-CD. Decreased HRV-CD values, especially in diabetics, are also associated with lower survival.
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Affiliation(s)
- Dorit Almoznino-Sarafian
- The Department of Internal Medicine F, Assaf Harofeh Medical Center (affiliated to the Sackler School of Medicine, Tel-Aviv University), Zerifin, Israel.
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10
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Nilsen KB, Tronvik E, Sand T, Gravdahl GB, Stovner LJ. Increased baroreflex sensitivity and heart rate variability in migraine patients. Acta Neurol Scand 2009; 120:418-23. [PMID: 19456305 DOI: 10.1111/j.1600-0404.2009.01173.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES We investigated whether spontaneous baroreflex sensitivity and heart rate variability (HRV) are different in migraine patients compared to healthy controls. MATERIAL AND METHODS Sixteen female migraine patients without aura aged 18-30 years and 14 age-matched healthy female controls were included. Continuous finger blood pressure and ECG were measured supine during paced breathing in the laboratory. Continuous finger blood pressure was measured the following 24-h period. Spontaneous baroreflex sensitivity (time-domain cross correlation baroreflex sensitivity) as well as HRV parameters were calculated. RESULTS Spontaneous baroreflex sensitivity measured in the 24-h period was increased in patients (20.6 ms/mmHg) compared to controls (15.7 ms/mmHg, P = 0.031). HRV parameters were increased during paced breathing in patients (P < 0.045). CONCLUSIONS The results suggest that central hypersensitivity in migraine also includes cardiovascular reactivity and may be important for the understanding of the mechanisms for the effect of antihypertensive drugs for migraine prophylaxis.
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Affiliation(s)
- K B Nilsen
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology, MTFS, 7489 Trondheim, Norway.
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Manzo A, Ootaki Y, Ootaki C, Kamohara K, Fukamachi K. Comparative study of heart rate variability between healthy human subjects and healthy dogs, rabbits and calves. Lab Anim 2009; 43:41-5. [DOI: 10.1258/la.2007.007085] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several studies have been performed to assess heart rate variability (HRV) in several species such as humans, dogs, pigs, calves, rabbits and rats. However, haemodynamic parameters are totally different in each animal, and optimal animal models for studying HRV corresponding to human HRV are still unclear. The purpose of this study was to assess HRV in human subjects and to compare those HRV data with canine, bovine and rabbit HRV data. The heart rate in the human subjects (62.8 ± 7.4 bpm) was significantly lower than that in dogs (124.2 ± 18.8 bpm, P < 0.001), calves (73.4 ± 10.5 bpm, P < 0.05), and rabbits (217.3 ± 21.5 bpm, P < 0.001). The low-frequency waves (LF) (57.9 ± 65.8 ms2/Hz) and high-frequency waves (HF) (33.8 ± 49.1 ms2/Hz) in rabbits were significantly lower than human LF (1216.3 ± 1220.7 ms2/Hz, P < 0.05) and HF (570.9 ± 581.3 ms2/Hz, P < 0.05). Dogs and calves showed similar LF (991.1 ± 646.1 ms2/Hz and 547.0 ± 256.9 ms2/Hz, respectively), HF (702.1 ± 394.1 ms2/Hz and 601.0 ± 666.6 ms2/Hz, respectively) and LF/HF (2.0 ± 1.3 and 2.5 ± 1.9, respectively) when compared with the human data. The present study shows that dogs and calves revealed similar HRV values as those which relate to humans. Large deviation of the HRV values in rabbits compared with humans might be considered when conducting animal studies using those animals to reflect human clinical situations.
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Affiliation(s)
- A Manzo
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Y Ootaki
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - C Ootaki
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - K Kamohara
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - K Fukamachi
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Platisa MM, Mazic S, Nestorovic Z, Gal V. Complexity of heartbeat interval series in young healthy trained and untrained men. Physiol Meas 2008; 29:439-50. [PMID: 18354245 DOI: 10.1088/0967-3334/29/4/002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The origin of heart rate variability (HRV) is largely in parasympathetic activity. The direct influence of sympathetic activity and other control mechanisms, especially at an increased HR, is not well understood. The objectives of the study were to investigate the influence of increasing HR on the properties of heartbeat interval (RR) series in young healthy subjects. ECG was recorded in 9 trained and 11 untrained young men during supine rest, standing, incremental running exercise and relaxation. During exercise, a breath-to-breath gas exchange was monitored. The RR time series analysis included the spectral analysis, detrended fluctuations analysis method and sample entropy (SampEn) calculation. During exercise, spectral powers were reduced dramatically in both groups. The dependence of short-term scaling exponent (alpha(1)) on the RR included a characteristic maximum, while SampEn for the same value of the RR had a minimum. The value of HR corresponding to the maximum of alpha(1) and minimum of SampEn (IHR) corresponded to the intrinsic HR obtained by an autonomic blockade. In trained subjects, the curves alpha(1) versus RR and SampEn versus RR were moved toward larger RR, compared with control. For HR values higher than IHR, alpha(1) decreased and SampEn increased. These results reveal that the complexity of the heart rhythm above intrinsic HR decreases with an increase in HR. We suggest that at the highest HR intrinsic heart control is reflected in the heart rhythm. We point out the possibility of developing a new non-invasive method for the determination of intrinsic HR from the curve alpha(1) versus RR.
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Affiliation(s)
- Mirjana M Platisa
- Institute of Biophysics, Faculty of Medicine, University of Belgrade, Visegradska 26, 11000 Belgrade, Serbia.
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Platisa MM, Gal V. Correlation properties of heartbeat dynamics. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:1247-52. [PMID: 18210101 DOI: 10.1007/s00249-007-0254-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2007] [Revised: 11/30/2007] [Accepted: 12/13/2007] [Indexed: 10/22/2022]
Abstract
In this study, we investigate correlation properties of fluctuations in heart interbeat (RR) time series in a broad range of physiological and pathological conditions. Using detrended fluctuation analysis (DFA) method we determined short-term (alpha 1) and long-term (alpha 2) scaling exponent. In addition, we calculated standard deviation of RR intervals (SDRR) as the simplest variability measure. We found that the difference between alpha 1 and alpha 2 is related to RR interval length. At the shortest RR intervals, which correspond to extreme physiological and pathological conditions, we found the highest reduction of variability and the biggest difference between scaling exponents. In this case, DFA reveals a white noise over short scales (alpha 1 about 0.5) and strongly correlated noise over large scales (alpha 2 about 1.5). With an increase in RR interval, accompanied by increased variability (increase in parasympathetic control), the difference between alpha 1 and alpha 2 decreases. The difference between scaling exponents disappeared in a state of efficient autonomic control. We suggest that the complexity in heart rhythm is achieved through coupling between intrinsically controlled heart rhythm and autonomic control, and that the model of stochastic resonance mechanism could be applied to this system.
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Affiliation(s)
- Mirjana M Platisa
- Institute of Biophysics, Faculty of Medicine, Belgrade University, Visegradska 26, 11000, Belgrade, Serbia.
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Aboy M, Cuesta-Frau D, Austin D, Mico-Tormos P. Characterization of Sample Entropy in the Context of Biomedical Signal Analysis. ACTA ACUST UNITED AC 2007; 2007:5943-6. [DOI: 10.1109/iembs.2007.4353701] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Lewis MJ, Short AL. Sample entropy of electrocardiographic RR and QT time-series data during rest and exercise. Physiol Meas 2007; 28:731-44. [PMID: 17664626 DOI: 10.1088/0967-3334/28/6/011] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sample entropy (SampEn) is a measure of the complexity of data. Few studies have compared the SampEn of electrocardiographic cardiac interval (RR) data (SampEn-RR) during differing physiological states, and none have examined SampEn for the corresponding QT interval (SampEn-QT). The aim of this study was to quantify SampEn-RR and SampEn-QT during rest and for a range of exercise workloads. Specific objectives were to assess both the utility of SampEn for discriminating between physiological states and the relationship of SampEn-RR with traditional measures of heart rate variability (HRV). Twelve males of similar age, mass and aerobic fitness participated. A three-lead ECG was recorded continuously during pre-exercise, progressive bicycle exercise and recovery, and beat-to-beat RR and QT intervals were quantified for sinus beats. SampEn and HRV were calculated within consecutive 1 min periods throughout. Consistent estimation of SampEn-RR and SampEn-QT was possible with an appropriate choice of SampEn parameters. SampEn-RR was sensitive to differing physiological conditions, but its discriminating ability was poorer than that of linear HRV indices. SampEn-RR was also negatively correlated with normalized LF and LF/HF parameters. We interpret changes in SampEn for RR and QT data in terms of the altered autonomic nervous system (ANS) control of either the atrial or the ventricular myocardium (or both) during discrete physiological states. We speculate that greater complexity in QT data might be explained by a direct ANS influence on the ventricular myocardium.
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Affiliation(s)
- M J Lewis
- Department of Sports Science, University of Wales Swansea, Swansea, UK.
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