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Critical Care
Published in: Critical Care 6/2004

Open Access 01-12-2004 | Research

Complex systems and the technology of variability analysis

Authors: Andrew JE Seely, Peter T Macklem

Published in: Critical Care | Issue 6/2004

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Abstract

Characteristic patterns of variation over time, namely rhythms, represent a defining feature of complex systems, one that is synonymous with life. Despite the intrinsic dynamic, interdependent and nonlinear relationships of their parts, complex biological systems exhibit robust systemic stability. Applied to critical care, it is the systemic properties of the host response to a physiological insult that manifest as health or illness and determine outcome in our patients. Variability analysis provides a novel technology with which to evaluate the overall properties of a complex system. This review highlights the means by which we scientifically measure variation, including analyses of overall variation (time domain analysis, frequency distribution, spectral power), frequency contribution (spectral analysis), scale invariant (fractal) behaviour (detrended fluctuation and power law analysis) and regularity (approximate and multiscale entropy). Each technique is presented with a definition, interpretation, clinical application, advantages, limitations and summary of its calculation. The ubiquitous association between altered variability and illness is highlighted, followed by an analysis of how variability analysis may significantly improve prognostication of severity of illness and guide therapeutic intervention in critically ill patients.
Literature
1.
Gallagher R, Appenzeller T: Beyond reductionism. Science 1999, 284: 79. 10.1126/science.284.5411.79
2.
Marshall JC: SIRS and MODS: what is their relevance to the science and practice of intensive care? Shock 2000, 14: 586-589.PubMed
3.
Seely AJ, Christou NV: Multiple organ dysfunction syndrome: exploring the paradigm of complex nonlinear systems. Crit Care Med 2000, 28: 2193-2200. 10.1097/00003246-200007000-00003PubMed
4.
Glass L MM: From Clocks to Chaos: The Rhythms of Life Princeton: Princeton University Press 1988.
5.
Que CL, Kenyon CM, Olivenstein R, Macklem PT, Maksym GN: Homeokinesis and short-term variability of human airway caliber. J Appl Physiol 2001, 91: 1131-1141.PubMed
6.
Glass L, Kaplan D: Time series analysis of complex dynamics in physiology and medicine. Med Prog Technol 1993, 19: 115-128.PubMed
7.
Que CL, Maksym G, Macklem PT: Deciphering the homeokinetic code of airway smooth muscle. Am J Respir Crit Care Med 2000, 161: S161-S163.PubMed
8.
Cunningham S, Symon AG, McIntosh N: The practical management of artifact in computerised physiological data. Int J Clin Monit Comput 1994, 11: 211-216. 10.1007/BF01139872PubMed
9.
Sapoznikov D, Luria MH, Mahler Y, Gotsman MS: Computer processing ofartifact and arrhythmias in heart rate variability analysis. Comput Methods Programs Biomed 1992, 39: 75-84. 10.1016/0169-2607(92)90060-KPubMed
10.
Berntson GG, Quigley KS, Jang JF, Boysen ST: An approach to artifact identification: application to heart period data. Psychophysiology 1990, 27: 586-598.PubMed
11.
Anonymous: Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation 1996, 93: 1043-1065.
12.
van Ravenswaaij-Arts CM, Kollee LA, Hopman JC, Stoelinga GB, van Geijn HP: Heart rate variability. Ann Intern Med 1993, 118: 436-447.PubMed
13.
Mietus JE, Peng CK, Henry I, Goldsmith RL, Goldberger AL: The pNNx files: re-examining a widely used heart rate variability measure. Heart 2002, 88: 378-380. 10.1136/heart.88.4.378PubMedPubMedCentral
14.
Rich MW, Saini JS, Kleiger RE, Carney RM, teVelde A, Freedland KE: Correlation of heart rate variability with clinical and angiographic variables and late mortality after coronary angiography. Am J Cardiol 1988, 62: 714-717. 10.1016/0002-9149(88)91208-8PubMed
15.
Van Hoogenhuyze D, Weinstein N, Martin GJ, Weiss JS, Schaad JW, Sahyouni XN, Fintel D, Remme WJ, Singer DH: Reproducibility and relation to meanheart rate of heart rate variability in normal subjects and in patients with congestive heart failure secondary to coronary artery disease. Am J Cardiol 1991, 68: 1668-1676. 10.1016/0002-9149(91)90327-HPubMed
16.
Tuininga YS, van Veldhuisen DJ, Brouwer J, Haaksma J, Crijns HJ, Man in't Veld AJ, Lie KI: Heart rate variability in left ventricular dysfunction and heart failure: effects and implications of drug treatment. Br Heart J 1994, 72: 509-513.PubMedPubMedCentral
17.
Szabo BM, van Veldhuisen DJ, van der Veer N, Brouwer J, De Graeff PA, Crijns HJ: Prognostic value of heart rate variability in chronic congestive heart failure secondary to idiopathic or ischemic dilated cardiomyopathy. Am J Cardiol 1997, 79: 978-980. 10.1016/S0002-9149(97)00026-XPubMed
18.
Ponikowski P, Anker SD, Chua TP, Szelemej R, Piepoli M, Adamopoulos S, Webb-Peploe K, Harrington D, Banasiak W, Wrabec K, et al.: Depressed heart rate variability as an independent predictor of death in chronic congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy. Am J Cardiol 1997, 79: 1645-1650. 10.1016/S0002-9149(97)00215-4PubMed
19.
Bigger JT Jr, Kleiger RE, Fleiss JL, Rolnitzky LM, Steinman RC, Miller JP: Components of heart rate variability measured during healing of acute myocardial infarction. Am J Cardiol 1988, 61: 208-215. 10.1016/0002-9149(88)90917-4PubMed
20.
Kleiger RE, Miller JP, Bigger JT Jr, Moss AJ: Decreased heart rate variability and its association with increased mortality after acute myocardial infarction. Am J Cardiol 1987, 59: 256-262. 10.1016/0002-9149(87)90795-8PubMed
21.
Casolo GC, Stroder P, Signorini C, Calzolari F, Zucchini M, Balli E, Sulla A, Lazzerini S: Heart rate variability during the acute phase of myocardial infarction. Circulation 1992, 85: 2073-2079.PubMed
22.
Singh N, Mironov D, Armstrong PW, Ross AM, Langer A: Heart rate variability assessment early after acute myocardial infarction. Pathophysiological and prognostic correlates. GUSTO ECG Substudy Investigators. Global Utilization of Streptokinase and TPA for Occluded Arteries. Circulation 1996, 93: 1388-1395.PubMed
23.
Zuanetti G, Neilson JM, Latini R, Santoro E, Maggioni AP, Ewing DJ: Prognostic significance of heart rate variability in post-myocardial infarction patients in the fibrinolytic era. The GISSI-2 results. Gruppo Italiano per lo Studio della Sopravvivenza nell' Infarto Miocardico. Circulation 1996, 94: 432-436.PubMed
24.
Tsuji H, Venditti FJ Jr, Manders ES, Evans JC, Larson MG, Feldman CL, Levy D: Reduced heart rate variability and mortality risk in an elderlycohort. The Framingham Heart Study. Circulation 1994, 90: 878-883.PubMed
25.
Lurje L, Wennerblom B, Tygesen H, Karlsson T, Hjalmarson A: Heart rate variability after acute myocardial infarction in patients treated with atenolol and metoprolol. Int J Cardiol 1997, 60: 157-164. 10.1016/S0167-5273(97)00104-6PubMed
26.
Osterhues HH, Kochs M, Hombach V: Time-dependent changes of heart rate variability after percutaneous transluminal angioplasty. Am Heart J 1998, 135: 755-761. 10.1016/S0002-8703(98)70033-XPubMed
27.
Wennerblom B, Lurje L, Solem J, Tygesen H, Uden M, Vahisalo R, Hjalmarson A: Reduced heart rate variability in ischemic heart disease is only partially caused by ischemia. An HRV study before and after PTCA. Cardiology 2000, 94: 146-151. 10.1159/000047309PubMed
28.
Dimmer C, Tavernier R, Gjorgov N, Van Nooten G, Clement DL, Jordaens L: Variations of autonomic tone preceding onset of atrial fibrillation after coronary artery bypass grafting. Am J Cardiol 1998, 82: 22-25. 10.1016/S0002-9149(98)00231-8PubMed
29.
Malik M, Camm AJ, Janse MJ, Julian DG, Frangin GA, Schwartz PJ: Depressed heart rate variability identifies postinfarction patients who might benefit from prophylactic treatment with amiodarone: a substudy of EMIAT (The European Myocardial Infarct Amiodarone Trial). J Am Coll Cardiol 2000, 35: 1263-1275. 10.1016/S0735-1097(00)00571-4PubMed
30.
Kleiger RE, Stein PK, Bosner MS, Rottman JN: Time domain measurements of heart rate variability. Cardiol Clin 1992, 10: 487-498.PubMed
31.
Stein PK: Assessing heart rate variability from real-world Holter reports. Card Electrophysiol Rev 2002, 6: 239-244. 10.1023/A:1016376924850PubMed
32.
Zhang CL, Popp FA: Log-normal distribution of physiological parameters and the coherence of biological systems. Med Hypotheses 1994, 43: 11-16. 10.1016/0306-9877(94)90042-6PubMed
33.
Tibby SM, Frndova H, Durward A, Cox PN: Novel method to quantify loss of heart rate variability in pediatric multiple organ failure. Crit Care Med 2003, 31: 2059-2067. 10.1097/01.CCM.0000069539.65980.58PubMed
34.
Stanley HE, Amaral LA, Goldberger AL, Havlin S, Ivanov P, Peng CK: Statistical physics and physiology: monofractal and multifractal approaches. Physica A 1999, 270: 309-324. 10.1016/S0378-4371(99)00230-7PubMed
35.
Sayers BM: Analysis of heart rate variability. Ergonomics 1973, 16: 17-32.PubMed
36.
Akselrod S, Gordon D, Ubel FA, Shannon DC, Berger AC, Cohen RJ: Power spectrum analysis of heart rate fluctuation: a quantitative probe of beat-to-beat cardiovascular control. Science 1981, 213: 220-222.PubMed
37.
Campbell MJ: Spectral analysis of clinical signals: an interface between medical statisticians and medical engineers. Stat Methods Med Res 1996, 5: 51-66.PubMed
38.
Mehta SK, Super DM, Connuck D, Salvator A, Singer L, Fradley LG, Harcar-Sevcik RA, Kirchner HL, Kaufman ES: Heart rate variability in healthy newborn infants. Am J Cardiol 2002, 89: 50-53. 10.1016/S0002-9149(01)02162-2PubMed
39.
Bigger JT Jr, Fleiss JL, Steinman RC, Rolnitzky LM, Kleiger RE, Rottman JN: Correlations among time and frequency domain measures of heart period variability two weeks after acute myocardial infarction. Am J Cardiol 1992, 69: 891-898. 10.1016/0002-9149(92)90788-ZPubMed
40.
Pagani M, Lombardi F, Guzzetti S, Rimoldi O, Furlan R, Pizzinelli P, Sandrone G, Malfatto G, Dell'Orto S, Piccaluga E, et al.: Power spectral analysis of heart rate and arterial pressure variabilities as a marker of sympatho-vagal interaction in man and conscious dog. Circ Res 1986, 59: 178-193.
41.
Kamath MV, Fallen EL: Power spectral analysis of heart rate variability: a noninvasive signature of cardiac autonomic function. Crit Rev Biomed Eng 1993, 21: 245-311.PubMed
42.
Pagani M, Montano N, Porta A, Malliani A, Abboud FM, Birkett C, Somers VK: Relationship between spectral components of cardiovascular variabilities and direct measures of muscle sympathetic nerve activity in humans. Circulation 1997, 95: 1441-1448.PubMed
43.
Stein PK, Kleiger RE: Insights from the study of heart rate variability. Annu Rev Med 1999, 50: 249-261. 10.1146/annurev.med.50.1.249PubMed
44.
Malik M: Heart rate variability. Curr Opin Cardiol 1998, 13: 36-44.PubMed
45.
Notarius CF, Butler GC, Ando S, Pollard MJ, Senn BL, Floras JS: Dissociation between microneurographic and heart rate variability estimates of sympathetic tone in normal subjects and patients with heart failure. Clin Sci (Lond) 1999, 96: 557-565. 10.1042/CS19980347
46.
Notarius CF, Floras JS: Limitations of the use of spectral analysis of heart rate variability for the estimation of cardiac sympathetic activity in heart failure. Europace 2001, 3: 29-38. 10.1053/eupc.2000.0136PubMed
47.
Stauss HM: Heart rate variability. Am J Physiol Regul Integr Comp Physiol 2003, 285: R927-R931.PubMed
48.
Parati G, Saul JP, Di Rienzo M, Mancia G: Spectral analysis of blood pressure and heart rate variability in evaluating cardiovascular regulation. Hypertension 1995, 25: 1276-1286.PubMed
49.
Triedman JK, Cohen RJ, Saul JP: Mild hypovolemic stress alters autonomic modulation of heart rate. Hypertension 1993, 21: 236-247.PubMed
50.
Guzzetti S, Mezzetti S, Magatelli R, Porta A, De Angelis G, Rovelli G, Malliani A: Linear and non-linear 24 h heart rate variability in chronic heart failure. Auton Neurosci 2000, 86: 114-119. 10.1016/S1566-0702(00)00239-3PubMed
51.
van de Borne P, Montano N, Pagani M, Oren R, Somers VK: Absence of low-frequency variability of sympathetic nerve activity in severe heart failure. Circulation 1997, 95: 1449-1454.PubMed
52.
Bonaduce D, Petretta M, Marciano F, Vicario ML, Apicella C, Rao MA, Nicolai E, Volpe M: Independent and incremental prognostic value of heart rate variability in patients with chronic heart failure. Am Heart J 1999, 138: 273-284. 10.1016/S0002-8703(99)70112-2PubMed
53.
Guzzetti S, Piccaluga E, Casati R, Cerutti S, Lombardi F, Pagani M, Malliani A: Sympathetic predominance in essential hypertension: a studyemploying spectral analysis of heart rate variability. J Hypertens 1988, 6: 711-717.PubMed
54.
Mussalo H, Vanninen E, Ikaheimo R, Laitinen T, Laakso M, Lansimies E, Hartikainen J: Heart rate variability and its determinants in patients with severe or mild essential hypertension. Clin Physiol 2001, 21: 594-604. 10.1046/j.1365-2281.2001.00359.xPubMed
55.
van Boven AJ, Jukema JW, Haaksma J, Zwinderman AH, Crijns HJ, Lie KI: Depressed heart rate variability is associated with events in patients with stable coronary artery disease and preserved left ventricular function. REGRESS Study Group. Am Heart J 1998, 135: 571-576. 10.1016/S0002-8703(98)70269-8PubMed
56.
Pardo Y, Merz CN, Paul-Labrador M, Velasquez I, Gottdiener JS, Kop WJ, Krantz DS, Rozanski A, Klein J, Peter T: Heart rate variability reproducibility and stability using commercially available equipment in coronary artery disease with daily life myocardial ischemia. Am J Cardiol 1996, 78: 866-870. 10.1016/S0002-9149(96)00458-4PubMed
57.
Huang J, Sopher SM, Leatham E, Redwood S, Camm AJ, Kaski JC: Heart rate variability depression in patients with unstable angina. Am Heart J 1995, 130: 772-779. 10.1016/0002-8703(95)90076-4PubMed
58.
Poulsen SH, Jensen SE, Moller JE, Egstrup K: Prognostic value of left ventricular diastolic function and association with heart rate variability after a first acute myocardial infarction. Heart 2001, 86: 376-380. 10.1136/heart.86.4.376PubMedPubMedCentral
59.
Axelrod S, Lishner M, Oz O, Bernheim J, Ravid M: Spectral analysis of fluctuations in heart rate: an objective evaluation of autonomic nervous control in chronic renal failure. Nephron 1987, 45: 202-206.PubMed
60.
Lishner M, Akselrod S, Avi VM, Oz O, Divon M, Ravid M: Spectral analysis of heart rate fluctuations. A non-invasive, sensitive method for the early diagnosis of autonomic neuropathy in diabetes mellitus. J Auton Nerv Syst 1987, 19: 119-125. 10.1016/0165-1838(87)90005-1PubMed
61.
Toweill DL, Kovarik WD, Carr R, Kaplan D, Lai S, Bratton S, Goldstein B: Linear and nonlinear analysis of heart rate variability during propofol anesthesia for short-duration procedures in children. Pediatr Crit Care Med 2003, 4: 308-314. 10.1097/01.PCC.0000074260.93430.6APubMed
62.
Yien HW, Hseu SS, Lee LC, Kuo TB, Lee TY, Chan SH: Spectral analysis of systemic arterial pressure and heart rate signals as a prognostic tool for the prediction of patient outcome in the intensive care unit. Crit Care Med 1997, 25: 258-266. 10.1097/00003246-199702000-00011PubMed
63.
Barnaby D, Ferrick K, Kaplan DT, Shah S, Bijur P, Gallagher EJ: Heart rate variability in emergency department patients with sepsis. Acad Emerg Med 2002, 9: 661-670. 10.1197/aemj.9.7.661PubMed
64.
Korach M, Sharshar T, Jarrin I, Fouillot JP, Raphael JC, Gajdos P, Annane D: Cardiac variability in critically ill adults: influence of sepsis. Crit Care Med 2001, 29: 1380-1385. 10.1097/00003246-200107000-00013PubMed
65.
Schmidt HB, Werdan K, Muller-Werdan U: Autonomic dysfunction in the ICU patient. Curr Opin Crit Care 2001, 7: 314-322. 10.1097/00075198-200110000-00002PubMed
66.
Goldstein B: On the importance of sympathovagal balance. Crit Care Med 2001, 29: 1483-1484. 10.1097/00003246-200107000-00035PubMed
67.
Goldstein B, Fiser DH, Kelly MM, Mickelsen D, Ruttimann U, Pollack MM: Decomplexification in critical illness and injury: relationship between heart rate variability, severity of illness, and outcome. Crit Care Med 1998, 26: 352-357. 10.1097/00003246-199802000-00040PubMed
68.
Annane D, Trabold F, Sharshar T, Jarrin I, Blanc AS, Raphael JC, Gajdos P: Inappropriate sympathetic activation at onset of septic shock: a spectral analysis approach. Am J Respir Crit Care Med 1999, 160: 458-465.PubMed
69.
Mansier P, Clairambault J, Charlotte N, Medigue C, Vermeiren C, LePape G, Carre F, Gounaropoulou A, Swynghedauw B: Linear and non-linear analyses of heart rate variability: a minireview. Cardiovasc Res 1996, 31: 371-379. 10.1016/0008-6363(96)00009-0PubMed
70.
Furlan R, Guzzetti S, Crivellaro W, Dassi S, Tinelli M, Baselli G, Cerutti S, Lombardi F, Pagani M, Malliani A: Continuous 24-hour assessment of the neural regulation of systemic arterial pressure and RR variabilities in ambulant subjects. Circulation 1990, 81: 537-547.PubMed
71.
Pinna GD, Maestri R, Di Cesare A, Colombo R, Minuco G: The accuracy of power-spectrum analysis of heart-rate variability from annotated RR lists generated by Holter systems. Physiol Meas 1994, 15: 163-179. 10.1088/0967-3334/15/2/006PubMed
72.
Merri M, Farden DC, Mottley JG, Titlebaum EL: Sampling frequency of the electrocardiogram for spectral analysis of the heart rate variability. IEEE Trans Biomed Eng 1990, 37: 99-106. 10.1109/10.43621PubMed
73.
Novak P, Novak V: Time/frequency mapping of the heart rate, blood pressure and respiratory signals. Med Biol Eng Comput 1993, 31: 103-110.PubMed
74.
Di Rienzo M, Castiglioni P, Mancia G, Parati G, Pedotti A: 24 h sequential spectral analysis of arterial blood pressure and pulse interval in free-moving subjects. IEEE Trans Biomed Eng 1989, 36: 1066-1075. 10.1109/10.40813PubMed
75.
Crowe JA, Gibson NM, Woolfson MS, Somekh MG: Wavelet transform as apotential tool for ECG analysis and compression. J Biomed Eng 1992, 14: 268-272.PubMed
76.
Bak P: How Nature Works. New York: Copernicus-Springer-Verlag 1996.
77.
Gisiger T: Scale invariance in biology: coincidence or footprint ofa universal mechanism? Biol Rev Camb Philos Soc 2001, 76: 161-209. 10.1017/S1464793101005607PubMed
78.
Goldberger AL: Non-linear dynamics for clinicians: chaos theory, fractals, and complexity at the bedside. Lancet 1996, 347: 1312-1314. 10.1016/S0140-6736(96)90948-4PubMed
79.
Mandelbrot B: The Fractal Geometry of Nature (French edition published 1975.) New York: Freeman 1983.
80.
Kobayashi M, Musha T: 1/f fluctuation of heartbeat period. IEEE Trans Biomed Eng 1982, 29: 456-457.PubMed
81.
Szeto HH, Cheng PY, Decena JA, Cheng Y, Wu DL, Dwyer G: Fractal properties in fetal breathing dynamics. Am J Physiol 1992, 263: R141-R147.PubMed
82.
Fabry B, Maksym GN, Butler JP, Glogauer M, Navajas D, Fredberg JJ: Scaling the microrheology of living cells. Phys Rev Lett 2001, 87: 148102. 10.1103/PhysRevLett.87.148102PubMed
83.
Suki B: Fluctuations and power laws in pulmonary physiology. Am J Respir Crit Care Med 2002, 166: 133-137. 10.1164/rccm.200202-152PPPubMed
84.
Pikkujamsa SM, Makikallio TH, Sourander LB, Raiha IJ, Puukka P, Skytta J, Peng CK, Goldberger AL, Huikuri HV: Cardiac interbeat interval dynamics from childhood to senescence : comparison of conventional and new measures based on fractals and chaos theory. Circulation 1999, 100: 393-399.PubMed
85.
Jokinen V, Syvanne M, Makikallio TH, Airaksinen KE, Huikuri HV: Temporal age-related changes in spectral, fractal and complexity characteristics of heart rate variability. Clin Physiol 2001, 21: 273-281. 10.1046/j.1365-2281.2001.00326.xPubMed
86.
Bigger JT Jr, Steinman RC, Rolnitzky LM, Fleiss JL, Albrecht P, Cohen RJ: Power law behavior of RR-interval variability in healthy middle-aged persons, patients with recent acute myocardial infarction, and patients with heart transplants. Circulation 1996, 93: 2142-2151.PubMed
87.
Huikuri HV, Makikallio TH, Airaksinen KE, Seppanen T, Puukka P, Raiha IJ, Sourander LB: Power-law relationship of heart rate variability as apredictor of mortality in the elderly. Circulation 1998, 97: 2031-2036.PubMed
88.
Peng CK, Havlin S, Stanley HE, Goldberger AL: Quantification of scaling exponents and crossover phenomena in nonstationary heartbeat time series. Chaos 1995, 5: 82-87. 10.1063/1.166141PubMed
89.
Peng CK, Buldyrev SV, Goldberger AL, Havlin S, Mantegna RN, Simons M, Stanley HE: Statistical properties of DNA sequences. Physica A 1995, 221: 180-192. 10.1016/0378-4371(95)00247-5PubMed
90.
Peng CK, Buldyrev SV, Havlin S, Simons M, Stanley HE, Goldberger AL: Mosaic organization of DNA nucleotides. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1994, 49: 1685-1689. 10.1103/PhysRevE.49.1685PubMed
91.
Nunes Amaral LA, Goldberger AL, Ivanov P, Stanley HE: Scale-independent measures and pathologic cardiac dynamics. Phys Rev Lett 1998, 81: 2388-2391. 10.1103/PhysRevLett.81.2388PubMed
92.
Iyengar N, Peng CK, Morin R, Goldberger AL, Lipsitz LA: Age-relatedalterations in the fractal scaling of cardiac interbeat interval dynamics. Am J Physiol 1996, 271: R1078-R1084.PubMed
93.
Viswanathan GM, Peng CK, Stanley HE, Goldberger AL: Deviations fromuniform power law scaling in nonstationary time series. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1997, 55: 845-849. 10.1103/PhysRevE.55.845PubMed
94.
Mahon NG, Hedman AE, Padula M, Gang Y, Savelieva I, Waktare JE, Malik MM, Huikuri HV, McKenna WJ: Fractal correlation properties of R-R interval dynamics in asymptomatic relatives of patients with dilated cardiomyopathy. Eur J Heart Fail 2002, 4: 151-158. 10.1016/S1388-9842(01)00227-6PubMed
95.
Makikallio TH, Ristimae T, Airaksinen KE, Peng CK, Goldberger AL, Huikuri HV: Heart rate dynamics in patients with stable angina pectorisand utility of fractal and complexity measures. Am J Cardiol 1998, 81: 27-31. 10.1016/S0002-9149(97)00799-6PubMed
96.
Ho KK, Moody GB, Peng CK, Mietus JE, Larson MG, Levy D, Goldberger AL: Predicting survival in heart failure case and control subjects by use of fully automated methods for deriving nonlinear and conventional indices of heart rate dynamics. Circulation 1997, 96: 842-848.PubMed
97.
Makikallio TH, Koistinen J, Jordaens L, Tulppo MP, Wood N, Golosarsky B, Peng CK, Goldberger AL, Huikuri HV: Heart rate dynamics before spontaneous onset of ventricular fibrillation in patients with healed myocardial infarcts. Am J Cardiol 1999, 83: 880-884. 10.1016/S0002-9149(98)01068-6PubMed
98.
Penzel T, Kantelhardt JW, Grote L, Peter JH, Bunde A: Comparison ofdetrended fluctuation analysis and spectral analysis for heart rate variability in sleep and sleep apnea. IEEE Trans Biomed Eng 2003, 50: 1143-1151. 10.1109/TBME.2003.817636PubMed
99.
Tapanainen JM, Thomsen PE, Kober L, Torp-Pedersen C, Makikallio TH, Still AM, Lindgren KS, Huikuri HV: Fractal analysis of heart rate variability and mortality after an acute myocardial infarction. Am J Cardiol 2002, 90: 347-352. 10.1016/S0002-9149(02)02488-8PubMed
100.
Laitio TT, Huikuri HV, Kentala ES, Makikallio TH, Jalonen JR, Helenius H, Sariola-Heinonen K, Yli-Mayry S, Scheinin H: Correlation properties and complexity of perioperative RR-interval dynamics in coronary artery bypass surgery patients. Anesthesiology 2000, 93: 69-80. 10.1097/00000542-200007000-00015PubMed
101.
Peng CK, Mietus JE, Liu Y, Lee C, Hausdorff JM, Stanley HE, Goldberger AL, Lipsitz LA: Quantifying fractal dynamics of human respiration: age and gender effects. Ann Biomed Eng 2002, 30: 683-692. 10.1114/1.1481053PubMed
102.
Cernelc M, Suki B, Reinmann B, Hall GL, Frey U: Correlation properties of tidal volume and end-tidal O2and CO2concentrations in healthy infants. J Appl Physiol 2002, 92: 1817-1827.PubMed
103.
Varela M, Jimenez L, Farina R: Complexity analysis of the temperature curve: new information from body temperature. Eur J Appl Physiol 2003, 89: 230-237.PubMed
104.
Hwa RC, Ferree TC: Scaling properties of fluctuations in the humanelectroencephalogram. Phys Rev E Stat Nonlin Soft Matter Phys 2002, 66: 021901. 10.1103/PhysRevE.66.021901PubMed
105.
Shen Y, Olbrich E, Achermann P, Meier PF: Dimensional complexity and spectral properties of the human sleep EEG. Electroencephalograms. Clin Neurophysiol 2003, 114: 199-209. 10.1016/S1388-2457(02)00338-3PubMed
106.
Goldberger AL, Amaral LA, Glass L, Hausdorff JM, Ivanov PC, Mark RG, Mietus JE, Moody GB, Peng CK, Stanley HE: PhysioBank, PhysioToolkit, and PhysioNet: components of a new research resource for complex physiologic signals. Circulation 2000, 101: E215-E220.PubMed
107.
Willson K, Francis DP: A direct analytical demonstration of the essential equivalence of detrended fluctuation analysis and spectral analysis of RR interval variability. Physiol Meas 2003, 24: N1-N7. 10.1088/0967-3334/24/1/401PubMed
108.
Ivanov PC, Amaral LA, Goldberger AL, Havlin S, Rosenblum MG, Struzik ZR, Stanley HE: Multifractality in human heartbeat dynamics. Nature 1999, 399: 461-465. 10.1038/20924
109.
Echeverria JC, Woolfson MS, Crowe JA, Hayes-Gill BR, Croaker GD, Vyas H: Interpretation of heart rate variability via detrended fluctuation analysis and alphabeta filter. Chaos 2003, 13: 467-475. 10.1063/1.1562051PubMed
110.
Richman JS, Moorman JR: Physiological time-series analysis using approximate entropy and sample entropy. Am J Physiol Heart Circ Physiol 2000, 278: H2039-H2049.PubMed
111.
Pincus SM: Approximate entropy as a measure of system complexity. Proc Natl Acad Sci USA 1991, 88: 2297-2301.PubMed
112.
Pincus SM, Goldberger AL: Physiological time-series analysis: what does regularity quantify? Am J Physiol 1994, 266: H1643-H1656.PubMed
113.
Pincus S, Singer BH: Randomness and degrees of irregularity. Proc Natl Acad Sci USA 1996, 93: 2083-2088. 10.1073/pnas.93.5.2083PubMed
114.
Pincus SM: Assessing serial irregularity and its implications for health. Ann N Y Acad Sci 2001, 954: 245-267.PubMed
115.
Pincus S: Approximate entropy (ApEn) as a complexity measure. Chaos 1995, 5: 110-117. 10.1063/1.166092PubMed
116.
Lipsitz LA, Goldberger AL: Loss of 'complexity' and aging. Potential applications of fractals and chaos theory to senescence. JAMA 1992, 267: 1806-1809. 10.1001/jama.267.13.1806PubMed
117.
Goldberger AL, Peng CK, Lipsitz LA: What is physiologic complexity and how does it change with aging and disease? Neurobiol Aging 2002, 23: 23-26. 10.1016/S0197-4580(01)00266-4PubMed
118.
Ryan SM, Goldberger AL, Pincus SM, Mietus J, Lipsitz LA: Gender- and age-related differences in heart rate dynamics: are women more complex than men? J Am Coll Cardiol 1994, 24: 1700-1707.PubMed
119.
Vikman S, Makikallio TH, Yli-Mayry S, Pikkujamsa S, Koivisto AM, Reinikainen P, Airaksinen KE, Huikuri HV: Altered complexity and correlation properties of R-R interval dynamics before the spontaneous onset of paroxysmal atrial fibrillation. Circulation 1999, 100: 2079-2084.PubMed
120.
Hogue CW Jr, Domitrovich PP, Stein PK, Despotis GD, Re L, Schuessler RB, Kleiger RE, Rottman JN: RR interval dynamics before atrial fibrillation in patients after coronary artery bypass graft surgery. Circulation 1998, 98: 429-434.PubMed
121.
Schuckers SA: Use of approximate entropy measurements to classify ventricular tachycardia and fibrillation. J Electrocardiol 1998, Suppl: 101-105. 10.1016/S0022-0736(98)90300-4
122.
Pincus SM, Cummins TR, Haddad GG: Heart rate control in normal andaborted-SIDS infants. Am J Physiol 1993, 264: R638-R646.PubMed
123.
Fleisher LA, Pincus SM, Rosenbaum SH: Approximate entropy of heartrate as a correlate of postoperative ventricular dysfunction. Anesthesiology 1993, 78: 683-692.PubMed
124.
Godin PJ, Fleisher LA, Eidsath A, Vandivier RW, Preas HL, Banks SM, Buchman TG, Suffredini AF: Experimental human endotoxemia increases cardiac regularity: results from a prospective, randomized, crossover trial. Crit Care Med 1996, 24: 1117-1124. 10.1097/00003246-199607000-00009PubMed
125.
Hartman ML, Pincus SM, Johnson ML, Matthews DH, Faunt LM, Vance ML, Thorner MO, Veldhuis JD: Enhanced basal and disorderly growth hormone secretion distinguish acromegalic from normal pulsatile growth hormone release. J Clin Invest 1994, 94: 1277-1288.PubMedPubMedCentral
126.
van den Berg G, Pincus SM, Frolich M, Veldhuis JD, Roelfsema F: Reduced disorderliness of growth hormone release in biochemically inactive acromegaly after pituitary surgery. Eur J Endocrinol 1998, 138: 164-169. 10.1530/eje.0.1380164PubMed
127.
Meneilly GS, Ryan AS, Veldhuis JD, Elahi D: Increased disorderliness of basal insulin release, attenuated insulin secretory burst mass, and reduced ultradian rhythmicity of insulin secretion in older individuals. J Clin Endocrinol Metab 1997, 82: 4088-4093. 10.1210/jc.82.12.4088PubMed
128.
Schmitz O, Porksen N, Nyholm B, Skjaerbaek C, Butler PC, Veldhuis JD, Pincus SM: Disorderly and nonstationary insulin secretion in relatives of patients with NIDDM. Am J Physiol 1997, 272: E218-E226.PubMed
129.
Roelfsema F, Pincus SM, Veldhuis JD: Patients with Cushing's disease secrete adrenocorticotropin and cortisol jointly more asynchronously than healthy subjects. J Clin Endocrinol Metab 1998, 83: 688-692. 10.1210/jc.83.2.688PubMed
130.
Veldman RG, Frolich M, Pincus SM, Veldhuis JD, Roelfsema F: Growth hormone and prolactin are secreted more irregularly in patients with Cushing's disease. Clin Endocrinol (Oxf) 2000, 52: 625-632. 10.1046/j.1365-2265.2000.00994.x
131.
Prank K, Harms H, Dammig M, Brabant G, Mitschke F, Hesch RD: Is there low-dimensional chaos in pulsatile secretion of parathyroid hormone in normal human subjects? Am J Physiol 1994, 266: E653-E658.PubMed
132.
Bruhn J, Ropcke H, Hoeft A: Approximate entropy as an electroencephalographic measure of anesthetic drug effect during desflurane anesthesia. Anesthesiology 2000, 92: 715-726. 10.1097/00000542-200003000-00016PubMed
133.
Bruhn J, Bouillon TW, Shafer SL: Onset of propofol-induced burst suppression may be correctly detected as deepening of anaesthesia by approximate entropy but not by bispectral index. Br J Anaesth 2001, 87: 505-507. 10.1093/bja/87.3.505PubMed
134.
Bruhn J, Bouillon TW, Radulescu L, Hoeft A, Bertaccini E, Shafer SL: Correlation of approximate entropy, bispectral index, and spectral edge frequency 95 (SEF95) with clinical signs of "anesthetic depth" during coadministration of propofol and remifentanil. Anesthesiology 2003, 98: 621-627. 10.1097/00000542-200303000-00008PubMed
135.
Engoren M: Approximate entropy of respiratory rate and tidal volume during weaning from mechanical ventilation. Crit Care Med 1998, 26: 1817-1823.PubMed
136.
Caldirola D, Bellodi L, Caumo A, Migliarese G, Perna G: Approximate entropy of respiratory patterns in panic disorder. Am J Psychiatry 2004, 161: 79-87. 10.1176/appi.ajp.161.1.79PubMed
137.
Burioka N, Cornelissen G, Halberg F, Kaplan DT, Suyama H, Sako T, Shimizu E: Approximate entropy of human respiratory movement during eye-closed waking and different sleep stages. Chest 2003, 123: 80-86. 10.1378/chest.123.1.80PubMed
138.
Lake DE, Richman JS, Griffin MP, Moorman JR: Sample entropy analysis of neonatal heart rate variability. Am J Physiol Regul Integr Comp Physiol 2002, 283: R789-R797.PubMed
139.
Costa M, Goldberger AL, Peng CK: Multiscale entropy analysis of complex physiologic time series. Phys Rev Lett 2002, 89: 068102. 10.1103/PhysRevLett.89.068102PubMed
140.
Costa M, Goldberger AL, Peng CK: Multiscale entropy to distinguish physiologic and synthetic RR time series. Comput Cardiol 2002, 29: 137-140.PubMed
141.
Berger RD: Broken fractals: where's the break? J Cardiovasc Electrophysiol 2001, 12: 33-35. 10.1046/j.1540-8167.2001.00033.xPubMed
142.
Goldberger AL: Fractal variability versus pathologic periodicity: complexity loss and stereotypy in disease. Perspect Biol Med 1997, 40: 543-561.PubMed
143.
Vaillancourt DE, Newell KM: Changing complexity in human behavior and physiology through aging and disease. Neurobiol Aging 2002, 23: 1-11. 10.1016/S0197-4580(01)00310-4PubMed
144.
Vaillancourt DE, Newell KM: Complexity in aging and disease: response to commentaries. Neurobiol Aging 2002, 23: 27-29. 10.1016/S0197-4580(01)00310-4PubMed
145.
Taboada JA, Arcay B, Arias JE: Real time monitoring and analysis via the medical information bus, Part II. Med Biol Eng Comput 1997, 35: 535-539.PubMed
146.
Taboada JA, Arcay B, Arias JE: Real time monitoring and analysis via the medical information bus, Part I. Med Biol Eng Comput 1997, 35: 528-534.PubMed
147.
Goldstein B, McNames J, McDonald BA, Ellenby M, Lai S, Sun Z, Krieger D, Sclabassi RJ: Physiologic data acquisition system and database for the study of disease dynamics in the intensive care unit. Crit Care Med 2003, 31: 433-441. 10.1097/01.CCM.0000050285.93097.52PubMed
148.
Kowallik P, Jacobi I, Jirmann A, Meesmann M, Schmidt M, Wirtz H: Breath-to-breath variability correlates with apnea-hypopnea index in obstructive sleep apnea. Chest 2001, 119: 451-459. 10.1378/chest.119.2.451PubMed
149.
Fathizadeh P, Shoemaker WC, Wo CC, Colombo J: Autonomic activity in trauma patients based on variability of heart rate and respiratory rate. Crit Care Med 2004, 32: 1300-1305. 10.1097/01.CCM.0000127776.78490.E4PubMed
150.
Garrard CS, Kontoyannis DA, Piepoli M: Spectral analysis of heart rate variability in the sepsis syndrome. Clin Auton Res 1993, 3: 5-13. 10.1007/BF01819137PubMed
151.
Piepoli M, Garrard CS, Kontoyannis DA, Bernardi L: Autonomic control of the heart and peripheral vessels in human septic shock. Intensive Care Med 1995, 21: 112-119. 10.1007/BF01726532PubMed
152.
Akay M, Mulder EJ: Effects of maternal alcohol intake on fractal properties in human fetal breathing dynamics. IEEE Trans Biomed Eng 1998, 45: 1097-1103. 10.1109/10.709552PubMed
153.
Hausdorff JM, Ashkenazy Y, Peng CK, Ivanov PC, Stanley HE, Goldberger AL: When human walking becomes random walking: fractal analysis and modeling of gait rhythm fluctuations. Physica A 2001, 302: 138-147. 10.1016/S0378-4371(01)00460-5PubMed
154.
Hausdorff JM, Cudkowicz ME, Firtion R, Wei JY, Goldberger AL: Gait variability and basal ganglia disorders: stride-to-stride variations of gait cycle timing in Parkinson's disease and Huntington's disease. Mov Disord 1998, 13: 428-437. 10.1002/mds.870130310PubMed
155.
Hausdorff JM, Lertratanakul A, Cudkowicz ME, Peterson AL, Kaliton D, Goldberger AL: Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis. J Appl Physiol 2000, 88: 2045-2053.PubMed
156.
van Emmerik RE, van Wegen EE: On the functional aspects of variability in postural control. Exerc Sport Sci Rev 2002, 30: 177-183. 10.1097/00003677-200210000-00007PubMed
157.
Gottschalk A, Bauer MS, Whybrow PC: Evidence of chaotic mood variation in bipolar disorder. Arch Gen Psychiatry 1995, 52: 947-959.PubMed
158.
Ehlers CL: Chaos and complexity. Can it help us to understand mood and behavior? Arch Gen Psychiatry 1995, 52: 960-964.PubMed
159.
Maj M, Magliano L, Pirozzi R, Marasco C, Guarneri M: Validity of rapid cycling as a course specifier for bipolar disorder. Am J Psychiatry 1994, 151: 1015-1019.PubMed
160.
Goldberger AL, Kobalter K, Bhargava V: 1/f-like scaling in normal neutrophil dynamics: implications for hematologic monitoring. IEEE Trans Biomed Eng 1986, 33: 874-876.PubMed
161.
Haurie C, Person R, Dale DC, Mackey MC: Hematopoietic dynamics in grey collies. Exp Hematol 1999, 27: 1139-1148. 10.1016/S0301-472X(99)00051-XPubMed
162.
Toweill D, Sonnenthal K, Kimberly B, Lai S, Goldstein B: Linear and nonlinear analysis of hemodynamic signals during sepsis and septic shock. Crit Care Med 2000, 28: 2051-2057. 10.1097/00003246-200006000-00063PubMed
163.
Bruhn J, Lehmann LE, Ropcke H, Bouillon TW, Hoeft A: Shannon entropy applied to the measurement of the electroencephalographic effects of desflurane. Anesthesiology 2001, 95: 30-35. 10.1097/00000542-200107000-00010PubMed
164.
Bruhn J, Ropcke H, Rehberg B, Bouillon T, Hoeft A: Electroencephalogram approximate entropy correctly classifies the occurrence of burst suppression pattern as increasing anesthetic drug effect. Anesthesiology 2000, 93: 981-985. 10.1097/00000542-200010000-00018PubMed
Metadata
Title
Complex systems and the technology of variability analysis
Authors
Andrew JE Seely
Peter T Macklem
Publication date
01-12-2004
Publisher
BioMed Central
Published in
Critical Care / Issue 6/2004
Electronic ISSN: 1364-8535
DOI
https://doi.org/10.1186/cc2948

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