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We exploit time reversibility analysis, checking the invariance of statistical features of a series after time reversal, to detect temporal asymmetries of short-term heart period variability series. Reversibility indexes were extracted from 22 healthy fetuses between 16th to 40th wk of gestation and from 17 healthy humans (aged 21 to 54, median=28) during(More)
OBJECTIVE To examine the possible use of magnetocardiography in the diagnosis of fetal arrhythmias. DESIGN Investigation of routinely examined pregnant women, as well as women referred because of arrhythmias or other reasons. PARTICIPANTS Sixty-three women between the 13th and 42nd week of pregnancy. METHODS Recording of 189 fetal magnetocardiograms,(More)
The investigation of foetal reaction to internal and external conditions and stimuli is an important tool in the characterization of the developing neural integration of the foetus. An interesting example of this is the study of the interrelationship between the foetal and the maternal heart rate. Recent studies have shown a certain likelihood of occasional(More)
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(More)
The neurochemical environment of nontumorous white matter tissue was investigated in 135 single voxel spectra of "healthy" white matter regions of 43 tumor patients and 129 spectra of 52 healthy subjects. Spectra were acquired with short TE and TR values. With the data of tumor patients, it was examined whether differences were caused by the tumor itself or(More)
BACKGROUND 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,(More)
The integrated exposure uptake biokinetic model for lead in children was developed to provide plausible blood lead distributions corresponding to particular combinations of multimedia lead exposure. The model is based on a set of equations that convert lead exposure (expressed as micrograms per day) to blood lead concentration (expressed as micrograms per(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. 177 magnetocardiograms were recorded in 62 pregnancies (16th–42nd week of gestation). Fetal and maternal RR interval time series were constructed(More)
OBJECTIVE The aim of this study was to examine changes in the heart rate variability based on the frequency power spectrum of healthy fetuses during the second and third trimester of pregnancy. METHODS We analyzed 222 fetal magnetocardiograms recorded in 49 healthy singleton pregnancies between the 16th and 42nd week. Discrete Fourier transformation was(More)
The fluctuations of the cardiac interbeat series contain rich information because they reflect variations of other functions on different time scales (e.g., respiration or blood pressure control). Nonlinear measures such as complexity and fractal scaling properties derived from 24 h heart rate dynamics of healthy subjects vary from childhood to old age. In(More)