Papers by Henrik Bettermann
Die Bestimmung der Atemfrequenz aus der respiratorischen Sinusarrhythmie (RSA). Determination of Respiratory Rate on the Basis of Respiratory Sinus Arrhythmia
Biomedizinische Technik, 1996
Clinical Physiology, 2001
Objective of this study was to evaluate cardiac autonomic function in female breast cancer patien... more Objective of this study was to evaluate cardiac autonomic function in female breast cancer patients on the basis of linear and nonlinear heart rate variability (HRV) as well as on musical heart rate rhythmicity. The latter method has been recently developed and enables particularly the quantification of cardiorespiratory coordination solely on the basis of ECG recordings. To provide a broad basis of comparability, 37 breast cancer patients were compared with 37 age-matched healthy women and 40 age-matched female diabetic patients who serve as pathological controls. During night sleep, all parameters showed a tendency towards lower variability, complexity, or rhythmicity of HRV in cancer patients. The most prominent alterations were found for the binary pattern predominance and for the ratio of heart rate and respiration. In particular, when comparing metastasized and non-metastasized cancer patients, the discriminatory power of binary heart rate rhythmicity emerges: the histograms of one-hour intervals during night sleep with a predominance of cyclically recurrent phase locking patterns unveiled a clear transition from higher to lower cardiorespiratory coordination ratios and to a loss of coordination capability in metastasized patients.
Herzschrittmachertherapie Und Elektrophysiologie, 2000
Fetal heart rate variability reflects fetal development and is affected by pathological condition... more Fetal heart rate variability reflects fetal development and is affected by pathological conditions. The aim of this study was to examine fetal heart period irregularity by focussing on nonlinear dynamical components. We recorded 165 fetal magnetocardiograms in 39 healthy pregnancies between the 16th and 41st week. The irregularity of the RR time series of each recording was quantified on the basis of the approximate entropy (ApEn). In order to estimate the nonlinear component, a surrogate time series was generated for each time series and ApEn was again calculated. Next, the purely dynamical aspect of the series was examined using a binary representation reflecting increase or decrease in RR interval of the original time series. ApEn of the original time series increased during pregnancy with a significant dependence on gestational age (p < 0.0005). The ApEn values of the surrogate data increased similarly although the power of the relationship to week of gestation was weaker (r original = 0.68, r surrogate = 0.46). Also the values of the surrogate series were generally higher, the mean difference being 0.24±0.24 (p < 0.0005). ApEn of the binary series revealed no dependency on gestational age but again the values for the surrogate series were higher than those for the original series. The increase in irregularity of RR interval time series during pregnancy can be attributed in part to an irregular, nonlinear temporal structure and is not solely due to linear autocorrelations. Reducing information by constructing time series using binary symbolization which ignores the absolute beat durations resulted in a loss of dependency on gestational age but a retention of nonlinearity. The ability to quantify these processes promises to aid in prenatal risk stratification.
Biomedical Engineering Online, 2004
The univariate approaches used to analyze heart rate variability have recently been extended by s... more The univariate approaches used to analyze heart rate variability have recently been extended by several bivariate approaches with respect to cardiorespiratory coordination. Some approaches are explicitly based on mathematical models which investigate the synchronization between weakly coupled complex systems. Others use an heuristic approach, i.e. characteristic features of both time series, to develop appropriate bivariate methods.
Fetal heart rate variability and complexity in the course of pregnancy
Early Human Development, 1999
The status of nonlinear dynamics in the analysis of heart rate variability
Herzschrittmachertherapie Und Elektrophysiologie, 2000
Dimensional analysis of RR dynamic in 24 hour electrocardiograms
Acta Biotheoretica, 1992
Using dimensional analysis, we demonstrate that it is possible to quantify changes in the topolog... more Using dimensional analysis, we demonstrate that it is possible to quantify changes in the topological structure of cardiac dynamics over long periods of time. A method was developed to calculate a dimension-like measure (referred to here as apparent dimension) from a correlation algorithm within a data window of 500 heart beats which is moved in equidistant steps over the time series of the RR intervals over 24 hours. The correspondence between the apparent dimension and the correlation dimension was tested using artificial data sequences. Furthermore 24 hour electrocardiographic recordings of two healthy subjects and of a patient with acute myocardial infarction were examined. The reliability of the analysis could be demonstrated and changes in dimension reflecting physiological as well as pathophysiological changes were observed.
Investigations of fetal heart rate in the course of pregnancy have suggested that its variability... more Investigations of fetal heart rate in the course of pregnancy have suggested that its variability may reflect nonlinear processes. In this study we examined 43 fetal RR tachograms derived from magnetocardiographic recordings in 8 healthy pregnancies. Irregularity in the RR interval sequences was quantified with the help of approximate entropy (ApEn). ApEn of the RR interval time series increased with gestational age. The use of surrogate data showed that this increase of irregularity is due to an increase of the nonlinear component in the heart rate. Furthermore, on the basis of a binary representation of the RR tachograms, it could be demonstrated that the dependency on gestational age resulted from the absolute values of the RR interval and not just from the dynamics of lengthening or shortening of the beat period.
Entropies of short binary sequences in heart period dynamics. Am J Physiol Heart Circ Physiol 278... more Entropies of short binary sequences in heart period dynamics. Am J Physiol Heart Circ Physiol 278: H2163-H2172, 2000.-Dynamic aspects of R-R intervals have often been analyzed by means of linear and nonlinear measures. The goal of this study was to analyze binary sequences, in which only the dynamic information is retained, by means of two different aspects of regularity. R-R interval sequences derived from 24-h electrocardiogram (ECG) recordings of 118 healthy subjects were converted to symbolic binary sequences that coded the beat-to-beat increase or decrease in the R-R interval. Shannon entropy was used to quantify the occurrence of short binary patterns (length N ϭ 5) in binary sequences derived from 10-min intervals. The regularity of the short binary patterns was analyzed on the basis of approximate entropy (ApEn). ApEn had a linear dependence on mean R-R interval length, with increasing irregularity occurring at longer R-R interval length. Shannon entropy of the same sequences showed that the increase in irregularity is accompanied by a decrease in occurrence of some patterns. Taken together, these data indicate that irregular binary patterns are more probable when the mean R-R interval increases. The use of surrogate data confirmed a nonlinear component in the binary sequence. Analysis of two consecutive 24-h ECG recordings for each subject demonstrated good intraindividual reproducibility of the results. In conclusion, quantification of binary sequences derived from ECG recordings reveals properties that cannot be found using the full information of R-R interval sequences. heart period dynamics; symbolic dynamics; approximate entropy; Shannon entropy; nonlinear dynamics; surrogate data IN RECENT YEARS linear measures of heart rate variability (HRV) have been applied in a wide range of contexts, leading to a well-established diagnostic tool with more or less accepted standards . Today, HRV is applied not only in cardiac diseases but in diseases that generally affect the autonomic nervous system (ANS). However, the influence of the sympa-The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked ''advertisement'' in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Bimodal dose-dependent effect on autonomic, cardiac control after oral administration of Atropa belladonna
Autonomic Neuroscience-basic & Clinical, 2001
The purpose of this prospective, placebo-controlled, randomized double-blind study was the examin... more The purpose of this prospective, placebo-controlled, randomized double-blind study was the examination of changes in the basic vegetative rhythms due to Cardiodoron ® . This medicine is a composition of extracts of blossoms from Primula officinalis and Onopordon acanthium and from the herbs of Hyoscyamus niger. In its clinical use it is known as a modulating medicine in the treatment of functional disturbances of the cardiovascular system. With use of Holter monitoring, 24-h ECG recordings were obtained from 100 healthy subjects of whom 50 took the composition and 50 a placebo. Heart rate variability was evaluated from the 24-h ECGs by means of a power spectral analysis based on the Fast Fourier Transformation (FFT). Regulative influences of changes on the rhythmic system due to the medicine were found. After four weeks of medication half of the verum group showed a tendency to an increased variability in the low and high frequency range at night (LFn: 0.04 -0.15 Hz, HFn: 0.15 -0.4 Hz) in contrast to the placebo group. The mean heart rate at night (HRn) showed a tendency of normalization in the verum group: in subjects with a low HRn the heart rate was increased and in subjects with a high HRn the heart rate was decreased. This effect could not be observed in the placebo group. After two fur ther weeks without any medication this difference between verum and placebo was abolished.
BMC Physiology, 2002
The objective was to evaluate and to compare two completely different detection algorithms of int... more The objective was to evaluate and to compare two completely different detection algorithms of intermittent (short-term) cardiorespiratory coordination during night sleep. The first method is based on a combination of respiratory flow and electrocardiogram recordings and determines the relative phases of R waves between successive onsets of inspiration. Intermittent phase coordination is defined as phase recurrence with accuracy α over at least k heartbeats. The second, recently introduced method utilizes only binary coded variations of heart rate (acceleration = 1, deceleration = 0) and identifies binary pattern classes which can be assigned to respiratory sinus arrhythmia (RSA). It is hypothesized that RSA pattern class recurrence over at least k heartbeats is strongly related with the intermittent phase coordination defined above.
In diesem Beitrag werden die wesentlichen Ergebnisse einer bereits im American Journal of Physiol... more In diesem Beitrag werden die wesentlichen Ergebnisse einer bereits im American Journal of Physiology publizierten Studie zur Therapeutischen Sprachgestaltung vorgestellt (1). In einem weiteren Beitrag wird der Versuch unternommen, die Ergebnisse aus der Sicht der anthroposophischen Medizin und Therapie darzustellen. Ziel der Studie war die Analyse der Synchronisation zwischen niederfrequenten Atmungsoszillationen und der respiratorischen Sinusarrhythmie (RSA) in der Herzfrequenz während der therapeutisch geleiteten Rezitation von Hexameter-Versen. In einer Querschnittstudie hatten 20 gesunde Probanden drei unterschiedliche Übungen auszuführen: Rezitation von Hexameter-Versen, kontrollierte Atmung und spontane Atmung. Jede Übung wurde in drei aufeinander folgende Messungen eingeteilt: 15-minütige Vorruhe im Sitzen (S1), Durchführung der Übung während 20 Minuten und 15-minütige Effektmessung im Sitzen (S2). Als Grundlage für die Analyse diente die zeitsynchrone Aufzeichnung von Luftfluss durch Nase / Mund und das Elektrokardiogramm. Die Synchronisation zwischen RSA und niederfrequenten Atmungsoszillation wurde mit einem Index γ quantifiziert. Dieser Index wurde aus der Analyse schwach gekoppelter chaotischer Oszillatoren übernommen. Während der Hexameter-Rezitation erhöhte sich die kardiorespiratorische Synchronisation in Gestalt (hohe γ -Werte). Während der kontrollierten Atmung war die kardiorespiratorische Synchronisation weniger stark ausgeprägt. Die Vorruhe (S1) und Effektmessung (S2) waren durch eine weitere Verringerung der Synchronisation gekennzeichnet. Und während der spontanen Atmung waren Herzschlag und Atmung fast vollständig desynchronisiert. Diese Ergebnisse resultieren vor allem aus den niederfrequenten Atmungsoszillationen die während der therapeutisch geleiteten Rezitation auftraten.
Effects of speech therapy with poetry on heart rate rhythmicity and cardiorespiratory coordination
International Journal of Cardiology, 2002
BMC Physiology, 2003
The prenatal condition offers a unique possibility of examining physiological interaction between... more The prenatal condition offers a unique possibility of examining physiological interaction between individuals. Goal of this work was to look for evidence of coordination between fetal and maternal cardiac systems.
E ffects of speech therapy with poetry on heart rate rhythmicity and cardiorespiratory coordination
Magnetokardiographie zur Erfassung fetaler Herzaktionen
Geburtshilfe Und Frauenheilkunde, 1995
Leeuwen. Musical rhythms in heart period dynamics: a cross-cultural and interdisciplinary approac... more Leeuwen. Musical rhythms in heart period dynamics: a cross-cultural and interdisciplinary approach to cardiac rhythms. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H1762-H1770, 1999.-The purpose of this study was to expand classic heart period analysis methods by techniques from ethnomusicology that explicitly take complex musical rhythm principles into consideration. The methods used are based on the theory of African music, the theory of symbolic dynamics, and combinatorial theory. Heart period tachograms from 192 24-h electrocardiograms of 96 healthy subjects were transformed into binary symbol sequences that were interpretable as elementary rhythmic (percussive) patterns, the time lines in African music. Using a hierarchical rhythm pattern scheme closely related to the Derler Rhythm Classification (from jazz theory), we calculated the predominance and stability of pattern classes. The results show that during sleep certain classes, specific to individuals, occurred in a cyclically recurrent manner and many times more often than expected. Simultaneously, other classes disappeared more or less completely. Moreover, the most frequent classes obviously originate from phase-locking processes in autonomic regulation (e.g., between respiratory and cardiac cycles). In conclusion, the new interdisciplinary method presented here demonstrates that heart period patterns, in particular those occurring during night sleep, can be interpreted as musical rhythms. This method may be of great potential use in music therapy research.
Komplexitätsanalyse der fetalen Herzfrequenz Bestimmung der Dimension
Biomedizinische Technik, 1997
Effects of an AnthroposophicalRemedy on Cardiorespiratory Regulation
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Papers by Henrik Bettermann