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Rodriguez J, Schulz S, Voss A, Giraldo BF. Classification of ischemic and dilated cardiomyopathy patients based on the analysis of the pulse transit time. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:5527-5530. [PMID: 34892376 DOI: 10.1109/embc46164.2021.9629519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cardiomyopathies diseases affects a great number of the elderly population. An adequate identification of the etiology of a cardiomyopathy patient is still a challenge. The aim of this study was to classify patients by their etiology in function of indexes extracted from the characterization of the pulse transit time (PTT). This time series represents the time taken by the pulse pressure to propagate through the length of the arterial tree and corresponding to the time between R peak of ECG and the mid-point of the diastolic to systolic slope in the blood pressure signal. For each patient, the PTT time series was extracted. Thirty cardiomyopathy patients (CMP) classified as ischemic (ICM - 15 patients) and dilated (DCM - 15 patients) were analyzed. Forty-three healthy subjects (CON) were used as a reference. The PTT time series was characterized through statistical descriptive indices and the joint symbolic dynamics method. The best indices were used to build support vector machine models. The optimal model to classify ICM versus DCM patients achieved 89.6% accuracy, 78.5% sensitivity, and 100% specificity. When comparing CMP patients and CON subjects, the best model achieved 91.3% accuracy, 91.3% sensitivity, and 88.3% specificity. Our results suggests a significantly lower pulse transit time in ischemic patients.Clinical relevance- This study analyzed the suitability of the pulse transit time for the classification of ICM and DCM patients.
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Schulz S, Haueisen J, Bär KJ, Voss A. The Cardiorespiratory Network in Healthy First-Degree Relatives of Schizophrenic Patients. Front Neurosci 2020; 14:617. [PMID: 32612509 PMCID: PMC7308718 DOI: 10.3389/fnins.2020.00617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 05/19/2020] [Indexed: 11/23/2022] Open
Abstract
Impaired heart rate- and respiratory regulatory processes as a sign of an autonomic dysfunction seems to be obviously present in patients suffering from schizophrenia. Since the linear and non-linear couplings within the cardiorespiratory system with respiration as an important homeostatic control mechanism are only partially investigated so far for those subjects, we aimed to characterize instantaneous cardiorespiratory couplings by quantifying the casual interaction between heart rate (HR) and respiration (RESP). Therefore, we investigated causal linear and non-linear cardiorespiratory couplings of 23 patients suffering from schizophrenia (SZO), 20 healthy first-degree relatives (REL) and 23 healthy subjects, who were age-gender matched (CON). From all participants' heart rate (HR) and respirations (respiratory frequency, RESP) were investigated for 30 min under resting conditions. The results revealed highly significant increased HR, reduced HR variability, increased respiration rates and impaired cardiorespiratory couplings in SZO in comparison to CON. SZO were revealed bidirectional couplings, with respiration as the driver (RESP → HR), and with weaker linear and non-linear coupling strengths when RESP influencing HR (RESP → HR) and with stronger linear and non-linear coupling strengths when HR influencing RESP (HR → RESP). For REL we found only significant increased HR and only slightly reduced cardiorespiratory couplings compared to CON. These findings clearly pointing to an underlying disease-inherent genetic component of the cardiac system for SZO and REL, and those respiratory alterations are only clearly present in SZO seem to be connected to their mental emotional states.
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Affiliation(s)
- Steffen Schulz
- Institute of Innovative Health Technologies (IGHT), University of Applied Sciences, Jena, Germany
| | - Jens Haueisen
- Institute of Biomedical Engineering and Informatics, Ilmenau University of Technology, Ilmenau, Germany
| | - Karl-Jürgen Bär
- Department of Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Jena, Germany
| | - Andreas Voss
- Institute of Innovative Health Technologies (IGHT), University of Applied Sciences, Jena, Germany
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Rodriguez J, Schulz S, Giraldo BF, Voss A. Risk Stratification in Idiopathic Dilated Cardiomyopathy Patients Using Cardiovascular Coupling Analysis. Front Physiol 2019; 10:841. [PMID: 31338037 PMCID: PMC6629896 DOI: 10.3389/fphys.2019.00841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 06/19/2019] [Indexed: 02/01/2023] Open
Abstract
Cardiovascular diseases are one of the most common causes of death; however, the early detection of patients at high risk of sudden cardiac death (SCD) remains an issue. The aim of this study was to analyze the cardio-vascular couplings based on heart rate variability (HRV) and blood pressure variability (BPV) analyses in order to introduce new indices for noninvasive risk stratification in idiopathic dilated cardiomyopathy patients (IDC). High-resolution electrocardiogram (ECG) and continuous noninvasive blood pressure (BP) signals were recorded in 91 IDC patients and 49 healthy subjects (CON). The patients were stratified by their SCD risk as high risk (IDCHR) when after two years the subject either died or suffered life-threatening complications, and as low risk (IDCLR) when the subject remained stable during this period. Values were extracted from ECG and BP signals, the beat-to-beat interval, and systolic and diastolic blood pressure, and analyzed using the segmented Poincaré plot analysis (SPPA), the high-resolution joint symbolic dynamics (HRJSD) and the normalized short time partial directed coherence methods. Support vector machine (SVM) models were built to classify these patients according to SCD risk. IDCHR patients presented lowered HRV and increased BPV compared to both IDCLR patients and the control subjects, suggesting a decrease in their vagal activity and a compensation of sympathetic activity. Both, the cardio -systolic and -diastolic coupling strength was stronger in high-risk patients when comparing with low-risk patients. The cardio-systolic coupling analysis revealed that the systolic influence on heart rate gets weaker as the risk increases. The SVM IDCLR vs. IDCHR model achieved 98.9% accuracy with an area under the curve (AUC) of 0.96. The IDC and the CON groups obtained 93.6% and 0.94 accuracy and AUC, respectively. To simulate a circumstance in which the original status of the subject is unknown, a cascade model was built fusing the aforementioned models, and achieved 94.4% accuracy. In conclusion, this study introduced a novel method for SCD risk stratification for IDC patients based on new indices from coupling analysis and non-linear HRV and BPV. We have uncovered some of the complex interactions within the autonomic regulation in this type of patient.
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Affiliation(s)
- Javier Rodriguez
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Automatic Control Department (ESAII), Barcelona East School of Engineering (EEBE), Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Steffen Schulz
- Institute of Innovative Health Technologies, Ernst-Abbe-Hochschule Jena, Jena, Germany
| | - Beatriz F Giraldo
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Automatic Control Department (ESAII), Barcelona East School of Engineering (EEBE), Universitat Politècnica de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Bioengenieria, Biomateriales y Nanomedicina, Madrid, Spain
| | - Andreas Voss
- Institute of Innovative Health Technologies, Ernst-Abbe-Hochschule Jena, Jena, Germany
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Schumann A, Schulz S, Voss A, Scharbrodt S, Baumert M, Bär KJ. Baroreflex Coupling Assessed by Cross-Compression Entropy. Front Physiol 2017; 8:282. [PMID: 28539889 PMCID: PMC5423936 DOI: 10.3389/fphys.2017.00282] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/19/2017] [Indexed: 11/13/2022] Open
Abstract
Estimating interactions between physiological systems is an important challenge in modern biomedical research. Here, we explore a new concept for quantifying information common in two time series by cross-compressibility. Cross-compression entropy (CCE) exploits the ZIP data compression algorithm extended to bivariate data analysis. First, time series are transformed into symbol vectors. Symbols of the target time series are coded by the symbols of the source series. Uncoupled and linearly coupled surrogates were derived from cardiovascular recordings of 36 healthy controls obtained during rest to demonstrate suitability of this method for assessing physiological coupling. CCE at rest was compared to that of isometric handgrip exercise. Finally, spontaneous baroreflex interaction assessed by CCEBRS was compared between 21 patients suffering from acute schizophrenia and 21 matched controls. The CCEBRS of original time series was significantly higher than in uncoupled surrogates in 89% of the subjects and higher than in linearly coupled surrogates in 47% of the subjects. Handgrip exercise led to sympathetic activation and vagal inhibition accompanied by reduced baroreflex sensitivity. CCEBRS decreased from 0.553 ± 0.030 at rest to 0.514 ± 0.035 during exercise (p < 0.001). In acute schizophrenia, heart rate, and blood pressure were elevated. Heart rate variability indicated a change of sympathovagal balance. The CCEBRS of patients with schizophrenia was reduced compared to healthy controls (0.546 ± 0.042 vs. 0.507 ± 0.046, p < 0.01) and revealed a decrease of blood pressure influence on heart rate in patients with schizophrenia. Our results indicate that CCE is suitable for the investigation of linear and non-linear coupling in cardiovascular time series. CCE can quantify causal interactions in short, noisy and non-stationary physiological time series.
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Affiliation(s)
- Andy Schumann
- Psychiatric Brain and Body Research Group, Department of Psychiatry and Psychotherapy, University Hospital JenaJena, Germany
| | - Steffen Schulz
- Institute of Innovative Health Technologies, Ernst-Abbe-Hochschule Jena, University of Applied Sciences JenaJena, Germany
| | - Andreas Voss
- Institute of Innovative Health Technologies, Ernst-Abbe-Hochschule Jena, University of Applied Sciences JenaJena, Germany
| | - Susann Scharbrodt
- Psychiatric Brain and Body Research Group, Department of Psychiatry and Psychotherapy, University Hospital JenaJena, Germany
| | - Mathias Baumert
- School of Electrical and Electronic Engineering, The University of AdelaideAdelaide, SA, Australia
| | - Karl-Jürgen Bär
- Psychiatric Brain and Body Research Group, Department of Psychiatry and Psychotherapy, University Hospital JenaJena, Germany
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Nonlinear causal influences assessed by mutual compression entropy. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2016. [DOI: 10.1515/cdbme-2016-0049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Autonomic control of the heart rate was demonstrated to be complex and nonlinear. Respiratory sinus arrhythima plays a crucial role in heart rate vagal modulation. Here we present an approach of assessing nonlinear causal relationships in bivariate time series, called mutual compression entropy (MCE). We applied MCE to cardiorespiratory data of 29 patients with acute schizophrenia and 29 matched controls. The method is based on data compression and estimates to which extend a (target) time series can be compressed regarding another time series (driver). In schizophrenia an elevated sympathetic and reduced parasympathetic heart rate modulation was found. The nonlinear influence of respiration on heart rate variability was demonstrated by a highly significant reduction of MCE (0.816 vs. 0.808, p¡0.01). In healthy subjects MCE was mainly related to sympathovagal balance. We conclude, that this index has the potential to uncover physiological information beyond linear measures.
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Porta A, Takahashi ACM, Catai AM. Cardiovascular coupling during graded postural challenge: comparison between linear tools and joint symbolic analysis. Braz J Phys Ther 2016; 20:461-470. [PMID: 27878227 PMCID: PMC5123266 DOI: 10.1590/bjpt-rbf.2014.0179] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/15/2016] [Indexed: 12/31/2022] Open
Abstract
Background A joint symbolic analysis (JSA) is applied to assess the strength of the
cardiovascular coupling from spontaneous beat-to-beat variability of the heart
period (HP) and the systolic arterial pressure (SAP) during an experimental
protocol inducing a gradual baroreflex unloading evoked by postural change (i.e.
graded head-up tilt). Method: The adopted JSA can quantify the degree of association between the HP and SAP
variabilities as a function of the time scale of the HP and SAP patterns.
Traditional linear tools assessing the HP-SAP coupling strength, such as squared
correlation coefficient, squared coherence function, and percentage of baroreflex
sequences, were computed as well for comparison. Results: We found that: i) JSA indicated that the strength of the cardiovascular coupling
at slow temporal scales gradually increased with the magnitude of the orthostatic
challenge, while that at fast temporal scales gradually decreased; ii) the squared
correlation coefficient and percentage of baroreflex sequences did not detect this
behavior; iii) even though squared coherence function could measure the magnitude
of the HP-SAP coupling as a function of the time scale, it was less powerful than
JSA owing to the larger dispersion of the frequency domain indexes. Conclusion: Due to its peculiar features and high statistical power, JSA deserves applications
to pathological groups in which the link between HP and SAP variabilities is lost
or decreased due to the overall depression or impairment of the cardiovascular
control.
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Affiliation(s)
- Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato, Milan, Italy
| | - Anielle C M Takahashi
- Departmento de Fisioterapia, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil
| | - Aparecida M Catai
- Departmento de Fisioterapia, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil
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Schulz S, Bolz M, Bär KJ, Voss A. Central- and autonomic nervous system coupling in schizophrenia. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2015.0178. [PMID: 27044986 PMCID: PMC4822441 DOI: 10.1098/rsta.2015.0178] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/10/2016] [Indexed: 05/03/2023]
Abstract
The autonomic nervous system (ANS) dysfunction has been well described in schizophrenia (SZ), a severe mental disorder. Nevertheless, the coupling between the ANS and central brain activity has been not addressed until now in SZ. The interactions between the central nervous system (CNS) and ANS need to be considered as a feedback-feed-forward system that supports flexible and adaptive responses to specific demands. For the first time, to the best of our knowledge, this study investigates central-autonomic couplings (CAC) studying heart rate, blood pressure and electroencephalogram in paranoid schizophrenic patients, comparing them with age-gender-matched healthy subjects (CO). The emphasis is to determine how these couplings are composed by the different regulatory aspects of the CNS-ANS. We found that CAC were bidirectional, and that the causal influence of central activity towards systolic blood pressure was more strongly pronounced than such causal influence towards heart rate in paranoid schizophrenic patients when compared with CO. In paranoid schizophrenic patients, the central activity was a much stronger variable, being more random and having fewer rhythmic oscillatory components. This study provides a more in-depth understanding of the interplay of neuronal and autonomic regulatory processes in SZ and most likely greater insights into the complex relationship between psychotic stages and autonomic activity.
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Affiliation(s)
- Steffen Schulz
- Institute of Innovative Health Technologies, University of Applied Sciences, Jena, Germany
| | - Mathias Bolz
- Department of Child and Adolescent Psychiatry, Pain and Autonomics-Integrative Research, University Hospital, Jena, Germany
| | - Karl-Jürgen Bär
- Department of Psychiatry and Psychotherapy, Pain and Autonomics-Integrative Research, University Hospital, Jena, Germany
| | - Andreas Voss
- Institute of Innovative Health Technologies, University of Applied Sciences, Jena, Germany
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Porta A, Baumert M, Cysarz D, Wessel N. Enhancing dynamical signatures of complex systems through symbolic computation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0099. [PMID: 25548265 PMCID: PMC4281870 DOI: 10.1098/rsta.2014.0099] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Affiliation(s)
- Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy IRCCS Galeazzi Orthopedic Institute, Milan, Italy
| | - Mathias Baumert
- School of Electrical and Electronic Engineering, University of Adelaide, Adelaide, South Australia, Australia
| | - Dirk Cysarz
- Integrated Curriculum for Anthroposophic Medicine, University of Witten/Herdecke, Witten, Germany Institute of Integrative Medicine, University of Witten/Herdecke, Witten, Germany
| | - Niels Wessel
- Department of Physics, Humboldt-Universität zu Berlin, Berlin, Germany
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