<p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with ... more <p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with three fetal beats occurring within two maternal beats at constant phase values (<i>n</i>:<i>m</i> = 3:2).</p
<p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with ... more <p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with three fetal beats occurring within two maternal beats at constant phase values (<i>n</i>:<i>m</i> = 3:2).</p
Psychological stress may have harmful physiological effects and result in deteriorating health. A... more Psychological stress may have harmful physiological effects and result in deteriorating health. Acute psychological stress acts also on cardiac autonomic regulation and may lead to nonstationarities in the interbeat interval series. We address the requirement of stationary RR interval series to calculate frequency domain parameters of heart rate variability (HRV) and use binary symbolic dynamics derived from RR interval differences to overcome this obstacle. 24 healthy subjects (12 female, 20–35 years) completed the following procedure: waiting period, Trier Social Stress Test to induce acute psychological stress, recovery period. An electrocardiogram was recorded throughout the procedure and HRV parameters were calculated for nine 5-min periods. Nonstationarities in RR interval series were present in all periods. During acute stress the average RR interval and SDNN decreased compared to rest before and after the stress test. Neither low frequency oscillations (LF), high frequency o...
OBJECTIVE Symbolic transformations of the cardiac interbeat interval series yield a coarse-graine... more OBJECTIVE Symbolic transformations of the cardiac interbeat interval series yield a coarse-grained description of the dynamical information of the underlying system and complement standard measures of heart rate variability. The most commonly utilized coarse graining procedures are strongly influenced by the presence of a few extreme values wasting precious symbols to code very unlikely values. APPROACH Here, we used a transformation procedure that ensured the appearance of each symbol with equal probability using a short alphabet, A 4 = {0, 1, 2, 3}, and a long alphabet, A 6 = {0, 1, 2, 3, 4, 5}. The procedure was applied to the cardiac interbeat interval series of 17 healthy subjects, obtained during graded head-up tilt tests at tilt table inclinations of 0°, 15°, 30°, 45°, 60°, 75°, 90°. The dynamics of the symbolic series was assessed by the rate of symbolic pattern categories. Symbolic patterns of length three were grouped according to the variations of the symbols in each pattern: no variation (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%) of the symbols. MAIN RESULTS As for the alphabet A 4, the linear regression analysis on tilt angle showed that 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. As for the alphabet A 6, the categories 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. SIGNIFICANCE The symbolic transformation ensuring a uniform distribution of the symbols is capable of reflecting changes in the cardiac autonomic nervous system during graded head-up tilt. This approach is more robust against outliers and data with skewed distributions compared to previously used symbolizations.
Monitoring the fetal behavior does not only have implications for acute care but also for identif... more Monitoring the fetal behavior does not only have implications for acute care but also for identifying developmental disturbances that burden the entire later life. The concept, of "fetal programming", also known as "developmental origins of adult disease hypothesis", e.g. applies for cardiovascular, metabolic, hyperkinetic, cognitive disorders. Since the autonomic nervous system is involved in all of those systems, cardiac autonomic control may provide relevant functional diagnostic and prognostic information. The fetal heart rate patterns (HRP) are one of the few functional signals in the prenatal period that relate to autonomic control and, therefore, is predestinated for its evaluation. The development of sensitive markers of fetal maturation and its disturbances requires the consideration of physiological fundamentals, recording technology and HRP parameters of autonomic control. Based on the ESGCO2016 special session on monitoring the fetal maturation we her...
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Coarse graining of physiological time series such as the cardiac interbeat interval series by mea... more Coarse graining of physiological time series such as the cardiac interbeat interval series by means of a symbolic transformation retains information about dynamical properties of the underlying system and complements standard measures of heart rate variability. The transformations of the original time series to the coarse grained symbolic series usually lead to a non-uniform occurrence of the different symbols, i.e. some symbols appear more often than others influencing the results of the subsequent symbolic series analysis. Here, we defined a transformation procedure to assure that each symbol appears with equal probability using a short alphabet {0,1,2,3} and a long alphabet {0,1,2,3,4,5}. The procedure was applied to the cardiac interbeat interval series RRi of 17 healthy subjects obtained during graded head-up tilt testing. The symbolic dynamics is analyzed by means of the occurrence of short sequences (`words&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;) of length 3. The occurrence of words is grouped according to words without variations of the symbols (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%). Linear regression analysis with respect to tilt angle showed that for the short alphabet 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. For the long alphabet 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. These results were slightly better compared to the results from non-uniform symbolic transformations reflecting the deviation from the mean. In conclusion, the symbolic transformation assuring the appearance of symbols with equal probability is capable of reflecting changes of the cardiac autonomic nervous system during graded head-up tilt. Furthermore, the transformation is independent of the time series&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; distribution.
Objective: In fetal diagnosis the myriad and diversity of heart rate variability (HRV) indices pr... more Objective: In fetal diagnosis the myriad and diversity of heart rate variability (HRV) indices prevents a comparable routine evaluation of disturbances in fetal development and well-being. The work aims at the extraction of a small set of HRV key indices that could help to establish a universal, overarching tool to screen for any disturbance. Approach: HRV indices were organized in categories of short-term (prefix s) and long-term (prefix l) amplitude fluctuations (AMP), complexity (COMP), and patterns (PATTERN) and common representatives for each category were extracted. This procedure was done with respect to the diagnostic value in the evaluation of the maturation age throughout the second and complete third trimester of pregnancy as well as to potential differences associated with maternal life-style factors (physical exercise, smoking), nutrient intervention (docosahexaenoic acid (DHA) supplementation), and complications of pregnancy (gestational diabetes mellitus (GDM), intra-...
European Journal of Integrative Medicine, Dec 1, 2009
Objectives Mind–body therapies combine body movements and accompanying guided imagery. Eurythmy t... more Objectives Mind–body therapies combine body movements and accompanying guided imagery. Eurythmy therapy (harmonious rhythm, EYT) is a mind–body therapy that is based on the principles of Anthroposophic Medicine. It uses harmonious body movements and guided imagery according to the state of movement. It has been shown that different EYT exercises show a distinct impact on heart rate variability. Here, we investigate whether two different EYT exercises (‘Migraine B’/MigB and ‘I Think The Saying’/ITTS) also affect coordination of heartbeat and respiration (cardiorespiratory interaction). Methods A total of 20 healthy subjects (average age: 29.1±9.3 years, 13 female, 7 male) carried out the following sequence of exercises: rest–YET–rest–CE1–rest–CE2–rest. Each exercise and each resting period (sitting position) lasted 8 min (total duration: approx. 60 min). During control exercise 1 (CE1) the same movements as in EYT were carried out without guided imagery and during CE2 the subjects walked on the spot. An electrocardiogram and the nasal/oral airflow were recorded throughout the procedure. The respiratory rate was calculated using the airflow trace. Cardiorespiratory interaction was quantified by the ratio of heart rate and respiratory rate (HRR). The temporal relationship between heartbeat and respiration was quantified by the amount of phase coordinated heartbeats (PCH%) and its accompanying ratio of heart rate and respiratory rate (PCR). Results During MigB the respiratory rate was 14.4 cycles per minute (cpm) on average. The respiratory rates increased during CE1 (16.7 cpm) and CE2 (23.0 cpm). During MigB HRR was 6.6 and decreased during CE1 (5.8) and CE2 (4.9). PCH% decreased from 6.9% during MigB to 2.4% during CE1 and increased to 8.3% during CE2. PCR was the same during MigB and CE1 (4.7) and decreased during CE2 (4.3). During ITTS the respiratory rate was 14.7 cpm and it increased during CE1 and CE2 (16.6 and 19.2 cpm). HRR was 6.6 during ITTS and decreased during CE1 (5.7) and CE2 (4.7). PCH% was 7.4% and increased during CE1 (8.4%) and CE2 (11.1%). PCR was the same during ITTS and CE1 (4.8). Conclusion The respiratory rate, HRR and PCH% reflect differences between EYT, CE1 and CE2. However, only PCH% reflects differences between ‘Migraine B’ and ‘I Think The Saying’. In conclusion, we found that EYT de-coordinates rather than coordinates heartbeat and respiration because PCH% was lower during EYT compared to CE2.
Intracranial pressure (ICP) burden or pressure time dose (PTD) is a valuable clinical indicator f... more Intracranial pressure (ICP) burden or pressure time dose (PTD) is a valuable clinical indicator for pending intracranial hypertension, mostly based on threshold exceedance. Pulse frequency and waveform morphology (WFM) of the ICP signal contribute to PTD. The temporal resolution of the ICP signal has a great influence on PTD calculation but has not been systematically studied yet. Hence, the temporal resolution of the ICP signal on PTD calculation is investigated. We retrospectively analysed continuous 48 h ICP recordings with high temporal resolution obtained from 94 patients at the intensive care unit who underwent neurosurgery due to an intracranial haemorrhage and received an intracranial pressure probe (43 females, median age: 72 years, range: 23 to 88 years). The cumulative area under the curve above the threshold of 20 mmHg was compared for different temporal resolutions of the ICP signal (beat-to-beat, 1 s, 300 s, 1800 s, 3600 s). Events with prolonged ICP elevation were com...
Slow breathing at 0.1 Hz (i.e., 6 cycles per minute, cpm) leads to strong cardiovascular oscillat... more Slow breathing at 0.1 Hz (i.e., 6 cycles per minute, cpm) leads to strong cardiovascular oscillations. However, the impact of breathing below 6 cpm is rarely addressed. We investigated the influence of OM chanting, an ancient Indian mantra, with approx. 3 respiratory cpm (0.05 Hz) on the synchronisation of heart period (RR), respiration (RESP) and systolic blood pressure (SBP). Nine healthy, trained speech practitioners chanted three sequences of five subsequent OM with 2 min pauses in between. Each single OM chanting consisted of taking a deep breath and a long “OM” during expiration and lasted approx. 20 s. ECG, respiration and blood pressure were recorded continuously, of which the RR tachogram, RESP and SBP were derived. Synchronisation between the signals was computed using the phase difference between two signals. During OM chanting synchronisation among the oscillations of RR, SBP and RESP was significantly increased compared to rest. Furthermore, OM chanting at breathing fre...
<p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with ... more <p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with three fetal beats occurring within two maternal beats at constant phase values (<i>n</i>:<i>m</i> = 3:2).</p
<p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with ... more <p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with three fetal beats occurring within two maternal beats at constant phase values (<i>n</i>:<i>m</i> = 3:2).</p
Psychological stress may have harmful physiological effects and result in deteriorating health. A... more Psychological stress may have harmful physiological effects and result in deteriorating health. Acute psychological stress acts also on cardiac autonomic regulation and may lead to nonstationarities in the interbeat interval series. We address the requirement of stationary RR interval series to calculate frequency domain parameters of heart rate variability (HRV) and use binary symbolic dynamics derived from RR interval differences to overcome this obstacle. 24 healthy subjects (12 female, 20–35 years) completed the following procedure: waiting period, Trier Social Stress Test to induce acute psychological stress, recovery period. An electrocardiogram was recorded throughout the procedure and HRV parameters were calculated for nine 5-min periods. Nonstationarities in RR interval series were present in all periods. During acute stress the average RR interval and SDNN decreased compared to rest before and after the stress test. Neither low frequency oscillations (LF), high frequency o...
OBJECTIVE Symbolic transformations of the cardiac interbeat interval series yield a coarse-graine... more OBJECTIVE Symbolic transformations of the cardiac interbeat interval series yield a coarse-grained description of the dynamical information of the underlying system and complement standard measures of heart rate variability. The most commonly utilized coarse graining procedures are strongly influenced by the presence of a few extreme values wasting precious symbols to code very unlikely values. APPROACH Here, we used a transformation procedure that ensured the appearance of each symbol with equal probability using a short alphabet, A 4 = {0, 1, 2, 3}, and a long alphabet, A 6 = {0, 1, 2, 3, 4, 5}. The procedure was applied to the cardiac interbeat interval series of 17 healthy subjects, obtained during graded head-up tilt tests at tilt table inclinations of 0°, 15°, 30°, 45°, 60°, 75°, 90°. The dynamics of the symbolic series was assessed by the rate of symbolic pattern categories. Symbolic patterns of length three were grouped according to the variations of the symbols in each pattern: no variation (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%) of the symbols. MAIN RESULTS As for the alphabet A 4, the linear regression analysis on tilt angle showed that 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. As for the alphabet A 6, the categories 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. SIGNIFICANCE The symbolic transformation ensuring a uniform distribution of the symbols is capable of reflecting changes in the cardiac autonomic nervous system during graded head-up tilt. This approach is more robust against outliers and data with skewed distributions compared to previously used symbolizations.
Monitoring the fetal behavior does not only have implications for acute care but also for identif... more Monitoring the fetal behavior does not only have implications for acute care but also for identifying developmental disturbances that burden the entire later life. The concept, of "fetal programming", also known as "developmental origins of adult disease hypothesis", e.g. applies for cardiovascular, metabolic, hyperkinetic, cognitive disorders. Since the autonomic nervous system is involved in all of those systems, cardiac autonomic control may provide relevant functional diagnostic and prognostic information. The fetal heart rate patterns (HRP) are one of the few functional signals in the prenatal period that relate to autonomic control and, therefore, is predestinated for its evaluation. The development of sensitive markers of fetal maturation and its disturbances requires the consideration of physiological fundamentals, recording technology and HRP parameters of autonomic control. Based on the ESGCO2016 special session on monitoring the fetal maturation we her...
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Coarse graining of physiological time series such as the cardiac interbeat interval series by mea... more Coarse graining of physiological time series such as the cardiac interbeat interval series by means of a symbolic transformation retains information about dynamical properties of the underlying system and complements standard measures of heart rate variability. The transformations of the original time series to the coarse grained symbolic series usually lead to a non-uniform occurrence of the different symbols, i.e. some symbols appear more often than others influencing the results of the subsequent symbolic series analysis. Here, we defined a transformation procedure to assure that each symbol appears with equal probability using a short alphabet {0,1,2,3} and a long alphabet {0,1,2,3,4,5}. The procedure was applied to the cardiac interbeat interval series RRi of 17 healthy subjects obtained during graded head-up tilt testing. The symbolic dynamics is analyzed by means of the occurrence of short sequences (`words&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;) of length 3. The occurrence of words is grouped according to words without variations of the symbols (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%). Linear regression analysis with respect to tilt angle showed that for the short alphabet 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. For the long alphabet 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. These results were slightly better compared to the results from non-uniform symbolic transformations reflecting the deviation from the mean. In conclusion, the symbolic transformation assuring the appearance of symbols with equal probability is capable of reflecting changes of the cardiac autonomic nervous system during graded head-up tilt. Furthermore, the transformation is independent of the time series&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; distribution.
Objective: In fetal diagnosis the myriad and diversity of heart rate variability (HRV) indices pr... more Objective: In fetal diagnosis the myriad and diversity of heart rate variability (HRV) indices prevents a comparable routine evaluation of disturbances in fetal development and well-being. The work aims at the extraction of a small set of HRV key indices that could help to establish a universal, overarching tool to screen for any disturbance. Approach: HRV indices were organized in categories of short-term (prefix s) and long-term (prefix l) amplitude fluctuations (AMP), complexity (COMP), and patterns (PATTERN) and common representatives for each category were extracted. This procedure was done with respect to the diagnostic value in the evaluation of the maturation age throughout the second and complete third trimester of pregnancy as well as to potential differences associated with maternal life-style factors (physical exercise, smoking), nutrient intervention (docosahexaenoic acid (DHA) supplementation), and complications of pregnancy (gestational diabetes mellitus (GDM), intra-...
European Journal of Integrative Medicine, Dec 1, 2009
Objectives Mind–body therapies combine body movements and accompanying guided imagery. Eurythmy t... more Objectives Mind–body therapies combine body movements and accompanying guided imagery. Eurythmy therapy (harmonious rhythm, EYT) is a mind–body therapy that is based on the principles of Anthroposophic Medicine. It uses harmonious body movements and guided imagery according to the state of movement. It has been shown that different EYT exercises show a distinct impact on heart rate variability. Here, we investigate whether two different EYT exercises (‘Migraine B’/MigB and ‘I Think The Saying’/ITTS) also affect coordination of heartbeat and respiration (cardiorespiratory interaction). Methods A total of 20 healthy subjects (average age: 29.1±9.3 years, 13 female, 7 male) carried out the following sequence of exercises: rest–YET–rest–CE1–rest–CE2–rest. Each exercise and each resting period (sitting position) lasted 8 min (total duration: approx. 60 min). During control exercise 1 (CE1) the same movements as in EYT were carried out without guided imagery and during CE2 the subjects walked on the spot. An electrocardiogram and the nasal/oral airflow were recorded throughout the procedure. The respiratory rate was calculated using the airflow trace. Cardiorespiratory interaction was quantified by the ratio of heart rate and respiratory rate (HRR). The temporal relationship between heartbeat and respiration was quantified by the amount of phase coordinated heartbeats (PCH%) and its accompanying ratio of heart rate and respiratory rate (PCR). Results During MigB the respiratory rate was 14.4 cycles per minute (cpm) on average. The respiratory rates increased during CE1 (16.7 cpm) and CE2 (23.0 cpm). During MigB HRR was 6.6 and decreased during CE1 (5.8) and CE2 (4.9). PCH% decreased from 6.9% during MigB to 2.4% during CE1 and increased to 8.3% during CE2. PCR was the same during MigB and CE1 (4.7) and decreased during CE2 (4.3). During ITTS the respiratory rate was 14.7 cpm and it increased during CE1 and CE2 (16.6 and 19.2 cpm). HRR was 6.6 during ITTS and decreased during CE1 (5.7) and CE2 (4.7). PCH% was 7.4% and increased during CE1 (8.4%) and CE2 (11.1%). PCR was the same during ITTS and CE1 (4.8). Conclusion The respiratory rate, HRR and PCH% reflect differences between EYT, CE1 and CE2. However, only PCH% reflects differences between ‘Migraine B’ and ‘I Think The Saying’. In conclusion, we found that EYT de-coordinates rather than coordinates heartbeat and respiration because PCH% was lower during EYT compared to CE2.
Intracranial pressure (ICP) burden or pressure time dose (PTD) is a valuable clinical indicator f... more Intracranial pressure (ICP) burden or pressure time dose (PTD) is a valuable clinical indicator for pending intracranial hypertension, mostly based on threshold exceedance. Pulse frequency and waveform morphology (WFM) of the ICP signal contribute to PTD. The temporal resolution of the ICP signal has a great influence on PTD calculation but has not been systematically studied yet. Hence, the temporal resolution of the ICP signal on PTD calculation is investigated. We retrospectively analysed continuous 48 h ICP recordings with high temporal resolution obtained from 94 patients at the intensive care unit who underwent neurosurgery due to an intracranial haemorrhage and received an intracranial pressure probe (43 females, median age: 72 years, range: 23 to 88 years). The cumulative area under the curve above the threshold of 20 mmHg was compared for different temporal resolutions of the ICP signal (beat-to-beat, 1 s, 300 s, 1800 s, 3600 s). Events with prolonged ICP elevation were com...
Slow breathing at 0.1 Hz (i.e., 6 cycles per minute, cpm) leads to strong cardiovascular oscillat... more Slow breathing at 0.1 Hz (i.e., 6 cycles per minute, cpm) leads to strong cardiovascular oscillations. However, the impact of breathing below 6 cpm is rarely addressed. We investigated the influence of OM chanting, an ancient Indian mantra, with approx. 3 respiratory cpm (0.05 Hz) on the synchronisation of heart period (RR), respiration (RESP) and systolic blood pressure (SBP). Nine healthy, trained speech practitioners chanted three sequences of five subsequent OM with 2 min pauses in between. Each single OM chanting consisted of taking a deep breath and a long “OM” during expiration and lasted approx. 20 s. ECG, respiration and blood pressure were recorded continuously, of which the RR tachogram, RESP and SBP were derived. Synchronisation between the signals was computed using the phase difference between two signals. During OM chanting synchronisation among the oscillations of RR, SBP and RESP was significantly increased compared to rest. Furthermore, OM chanting at breathing fre...
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