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Frasch MG. Heart Rate Variability Code: Does It Exist and Can We Hack It? Bioengineering (Basel) 2023; 10:822. [PMID: 37508849 PMCID: PMC10375964 DOI: 10.3390/bioengineering10070822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/13/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
A code is generally defined as a system of signals or symbols for communication. Experimental evidence is synthesized for the presence and utility of such communication in heart rate variability (HRV) with particular attention to fetal HRV: HRV contains signatures of information flow between the organs and of response to physiological or pathophysiological stimuli as signatures of states (or syndromes). HRV exhibits features of time structure, phase space structure, specificity with respect to (organ) target and pathophysiological syndromes, and universality with respect to species independence. Together, these features form a spatiotemporal structure, a phase space, that can be conceived of as a manifold of a yet-to-be-fully understood dynamic complexity. The objective of this article is to synthesize physiological evidence supporting the existence of HRV code: hereby, the process-specific subsets of HRV measures indirectly map the phase space traversal reflecting the specific information contained in the code required for the body to regulate the physiological responses to those processes. The following physiological examples of HRV code are reviewed, which are reflected in specific changes to HRV properties across the signal-analytical domains and across physiological states and conditions: the fetal systemic inflammatory response, organ-specific inflammatory responses (brain and gut), chronic hypoxia and intrinsic (heart) HRV (iHRV), allostatic load (physiological stress due to surgery), and vagotomy (bilateral cervical denervation). Future studies are proposed to test these observations in more depth, and the author refers the interested reader to the referenced publications for a detailed study of the HRV measures involved. While being exemplified mostly in the studies of fetal HRV, the presented framework promises more specific fetal, postnatal, and adult HRV biomarkers of health and disease, which can be obtained non-invasively and continuously.
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Affiliation(s)
- Martin Gerbert Frasch
- Department of Obstetrics and Gynecology and Institute on Human Development and Disability, University of Washington School of Medicine, Seattle, WA 98195, USA
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Sampling rate and heart rate variability: on metrics and health outcomes. J Biomed Inform 2022; 129:104061. [DOI: 10.1016/j.jbi.2022.104061] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/06/2022] [Accepted: 03/27/2022] [Indexed: 11/20/2022]
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Roux SG, Garnier NB, Abry P, Gold N, Frasch MG. Distance to Healthy Metabolic and Cardiovascular Dynamics From Fetal Heart Rate Scale-Dependent Features in Pregnant Sheep Model of Human Labor Predicts the Evolution of Acidemia and Cardiovascular Decompensation. Front Pediatr 2021; 9:660476. [PMID: 34414140 PMCID: PMC8369259 DOI: 10.3389/fped.2021.660476] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 06/21/2021] [Indexed: 01/27/2023] Open
Abstract
The overarching goal of the present work is to contribute to the understanding of the relations between fetal heart rate (FHR) temporal dynamics and the well-being of the fetus, notably in terms of predicting the evolution of lactate, pH and cardiovascular decompensation (CVD). It makes uses of an established animal model of human labor, where 14 near-term ovine fetuses subjected to umbilical cord occlusions (UCO) were instrumented to permit regular intermittent measurements of metabolites lactate and base excess, pH, and continuous recording of electrocardiogram (ECG) and systemic arterial blood pressure (to identify CVD) during UCO. ECG-derived FHR was digitized at the sampling rate of 1,000 Hz and resampled to 4 Hz, as used in clinical routine. We focused on four FHR variability features which are tunable to temporal scales of FHR dynamics, robustly computable from FHR sampled at 4 Hz and within short-time sliding windows, hence permitting a time-dependent, or local, analysis of FHR which helps dealing with signal noise. Results show the sensitivity of the proposed features for early detection of CVD, correlation to metabolites and pH, useful for early acidosis detection and the importance of coarse time scales (2.5-8 s) which are not disturbed by the low FHR sampling rate. Further, we introduce the performance of an individualized self-referencing metric of the distance to healthy state, based on a combination of the four features. We demonstrate that this novel metric, applied to clinically available FHR temporal dynamics alone, accurately predicts the time occurrence of CVD which heralds a clinically significant degradation of the fetal health reserve to tolerate the trial of labor.
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Affiliation(s)
- Stephane G. Roux
- Laboratoire de Physique, Université Lyon, Ens de Lyon, Université Claude Bernard, CNRS, Lyon, France
| | - Nicolas B. Garnier
- Laboratoire de Physique, Université Lyon, Ens de Lyon, Université Claude Bernard, CNRS, Lyon, France
| | - Patrice Abry
- Laboratoire de Physique, Université Lyon, Ens de Lyon, Université Claude Bernard, CNRS, Lyon, France
| | - Nathan Gold
- Department of Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Quantitative Analysis and Modelling, Fields Institute, Toronto, ON, Canada
| | - Martin G. Frasch
- Department of OBGYN, Center on Human Development and Disability, University of Washington, Seattle, WA, United States
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Frasch MG, Giussani DA. Heart during acidosis: Etiology and early detection of cardiac dysfunction. EClinicalMedicine 2021; 37:100994. [PMID: 34286236 PMCID: PMC8280510 DOI: 10.1016/j.eclinm.2021.100994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/02/2021] [Accepted: 06/07/2021] [Indexed: 11/25/2022] Open
Affiliation(s)
- Martin G. Frasch
- Department of Obstetrics and Gynecology and Center on Human Development and Disability (CHDD), University of Washigton School of Medicine, Seattle, WA, USA
| | - Dino A. Giussani
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, UK
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Gold N, Herry CL, Wang X, Frasch MG. Fetal Cardiovascular Decompensation During Labor Predicted From the Individual Heart Rate Tracing: A Machine Learning Approach in Near-Term Fetal Sheep Model. Front Pediatr 2021; 9:593889. [PMID: 34026680 PMCID: PMC8132964 DOI: 10.3389/fped.2021.593889] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 03/31/2021] [Indexed: 12/26/2022] Open
Abstract
Background: When exposed to repetitive umbilical cord occlusions (UCO) with worsening acidemia, fetuses eventually develop cardiovascular decompensation manifesting as pathological hypotensive arterial blood pressure (ABP) responses to fetal heart rate (FHR) decelerations. Failure to maintain cardiac output during labor is a key event leading up to brain injury. We reported that the timing of the event when a fetus begins to exhibit this cardiovascular phenotype is highly individual and was impossible to predict. Objective: We hypothesized that this phenotype would be reflected in the individual behavior of heart rate variability (HRV) as measured by root mean square of successive differences of R-R intervals (RMSSD), a measure of vagal modulation of HRV, which is known to increase with worsening acidemia. This is clinically relevant because HRV can be computed in real-time intrapartum. Consequently, we aimed to predict the individual timing of the event when a hypotensive ABP pattern would emerge in a fetus from a series of continuous RMSSD data. Study Design: Fourteen near-term fetal sheep were chronically instrumented with vascular catheters to record fetal arterial blood pressure, umbilical cord occluder to mimic uterine contractions occurring during human labor and ECG electrodes to compute the ECG-derived HRV measure RMSSD. All animals were studied over a ~6 h period. After a 1-2 h baseline control period, the animals underwent mild, moderate, and severe series of repetitive UCO. We applied the recently developed machine learning algorithm to detect physiologically meaningful changes in RMSSD dynamics with worsening acidemia and hypotensive responses to FHR decelerations. To mimic clinical scenarios using an ultrasound-based 4 Hz FHR sampling rate, we recomputed RMSSD from FHR sampled at 4 Hz and compared the performance of our algorithm under both conditions (1,000 Hz vs. 4 Hz). Results: The RMSSD values were highly non-stationary, with four different regimes and three regime changes, corresponding to a baseline period followed by mild, moderate, and severe UCO series. Each time series was characterized by seemingly randomly occurring (in terms of timing of the individual onset) increase in RMSSD values at different time points during the moderate UCO series and at the start of the severe UCO series. This event manifested as an increasing trend in RMSSD values, which counter-intuitively emerged as a period of relative stationarity for the time series. Our algorithm identified these change points as the individual time points of cardiovascular decompensation with 92% sensitivity, 86% accuracy and 92% precision which corresponded to 14 ± 21 min before the visual identification. In the 4 Hz RMSSD time series, the algorithm detected the event with 3 times earlier detection times than at 1,000 Hz, i.e., producing false positive alarms with 50% sensitivity, 21% accuracy, and 27% precision. We identified the overestimation of baseline FHR variability by RMSSD at a 4 Hz sampling rate to be the cause of this phenomenon. Conclusions: The key finding is demonstration of FHR monitoring to detect fetal cardiovascular decompensation during labor. This validates the hypothesis that our HRV-based algorithm identifies individual time points of ABP responses to UCO with worsening acidemia by extracting change point information from the physiologically related fluctuations in the RMSSD signal. This performance depends on the acquisition accuracy of beat to beat fluctuations achieved in trans-abdominal ECG devices and fails at the sampling rate used clinically in ultrasound-based systems. This has implications for implementing such an approach in clinical practice.
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Affiliation(s)
- Nathan Gold
- Department of Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Quantitative Analysis and Modelling, Fields Institute for Research in Mathematical Science, Toronto, ON, Canada
| | - Christophe L. Herry
- Dynamical Analysis Laboratory, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Xiaogang Wang
- Department of Mathematics and Statistics, York University, Toronto, ON, Canada
- Institute of Big Data, Qing Hua University, Beijing, China
| | - Martin G. Frasch
- Department of Obstetrics and Gynecology and Center on Human Development and Disability, University of Washington, Seattle, WA, United States
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Chiera M, Cerritelli F, Casini A, Barsotti N, Boschiero D, Cavigioli F, Corti CG, Manzotti A. Heart Rate Variability in the Perinatal Period: A Critical and Conceptual Review. Front Neurosci 2020; 14:561186. [PMID: 33071738 PMCID: PMC7544983 DOI: 10.3389/fnins.2020.561186] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/28/2020] [Indexed: 12/18/2022] Open
Abstract
Neonatal intensive care units (NICUs) greatly expand the use of technology. There is a need to accurately diagnose discomfort, pain, and complications, such as sepsis, mainly before they occur. While specific treatments are possible, they are often time-consuming, invasive, or painful, with detrimental effects for the development of the infant. In the last 40 years, heart rate variability (HRV) has emerged as a non-invasive measurement to monitor newborns and infants, but it still is underused. Hence, the present paper aims to review the utility of HRV in neonatology and the instruments available to assess it, showing how HRV could be an innovative tool in the years to come. When continuously monitored, HRV could help assess the baby’s overall wellbeing and neurological development to detect stress-/pain-related behaviors or pathological conditions, such as respiratory distress syndrome and hyperbilirubinemia, to address when to perform procedures to reduce the baby’s stress/pain and interventions, such as therapeutic hypothermia, and to avoid severe complications, such as sepsis and necrotizing enterocolitis, thus reducing mortality. Based on literature and previous experiences, the first step to efficiently introduce HRV in the NICUs could consist in a monitoring system that uses photoplethysmography, which is low-cost and non-invasive, and displays one or a few metrics with good clinical utility. However, to fully harness HRV clinical potential and to greatly improve neonatal care, the monitoring systems will have to rely on modern bioinformatics (machine learning and artificial intelligence algorithms), which could easily integrate infant’s HRV metrics, vital signs, and especially past history, thus elaborating models capable to efficiently monitor and predict the infant’s clinical conditions. For this reason, hospitals and institutions will have to establish tight collaborations between the obstetric, neonatal, and pediatric departments: this way, healthcare would truly improve in every stage of the perinatal period (from conception to the first years of life), since information about patients’ health would flow freely among different professionals, and high-quality research could be performed integrating the data recorded in those departments.
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Affiliation(s)
- Marco Chiera
- Research and Assistance for Infants to Support Experience Lab, Foundation Center for Osteopathic Medicine Collaboration, Pescara, Italy.,Research Commission on Manual Therapies and Mind-Body Disciplines, Societ Italiana di Psico Neuro Endocrino Immunologia, Rome, Italy
| | - Francesco Cerritelli
- Research and Assistance for Infants to Support Experience Lab, Foundation Center for Osteopathic Medicine Collaboration, Pescara, Italy
| | - Alessandro Casini
- Research and Assistance for Infants to Support Experience Lab, Foundation Center for Osteopathic Medicine Collaboration, Pescara, Italy
| | - Nicola Barsotti
- Research and Assistance for Infants to Support Experience Lab, Foundation Center for Osteopathic Medicine Collaboration, Pescara, Italy.,Research Commission on Manual Therapies and Mind-Body Disciplines, Societ Italiana di Psico Neuro Endocrino Immunologia, Rome, Italy
| | | | - Francesco Cavigioli
- Neonatal Intensive Care Unit, "V. Buzzi" Children's Hospital, Azienda Socio Sanitaria Territoriale Fatebenefratelli-Sacco, Milan, Italy
| | - Carla G Corti
- Pediatric Cardiology Unit-Pediatric Department, Azienda Socio Sanitaria Territoriale Fatebenefratelli-Sacco, Milan, Italy
| | - Andrea Manzotti
- Research and Assistance for Infants to Support Experience Lab, Foundation Center for Osteopathic Medicine Collaboration, Pescara, Italy.,Neonatal Intensive Care Unit, "V. Buzzi" Children's Hospital, Azienda Socio Sanitaria Territoriale Fatebenefratelli-Sacco, Milan, Italy.,Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
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Frasch MG, Herry CL, Niu Y, Giussani DA. First evidence that intrinsic fetal heart rate variability exists and is affected by hypoxic pregnancy. J Physiol 2020; 598:249-263. [PMID: 31802494 DOI: 10.1113/jp278773] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/11/2019] [Indexed: 02/02/2023] Open
Abstract
KEY POINTS We introduce a technique to test whether intrinsic fetal heart rate variability (iFHRV) exists and we show the utility of the technique by testing the hypothesis that iFHRV is affected by chronic fetal hypoxia, one of the most common adverse outcomes of human pregnancy complicated by fetal growth restriction. Using an established late gestation ovine model of fetal development under chronic hypoxic conditions, we identify iFHRV in isolated fetal hearts and show that it is markedly affected by hypoxic pregnancy. Therefore, the isolated fetal heart has intrinsic variability and carries a memory of adverse intrauterine conditions experienced during the last third of pregnancy. ABSTRACT Fetal heart rate variability (FHRV) emerges from influences of the autonomic nervous system, fetal body and breathing movements, and from baroreflex and circadian processes. We tested whether intrinsic heart rate variability (iHRV), devoid of any external influences, exists in the fetal period and whether it is affected by chronic fetal hypoxia. Chronically catheterized ewes carrying male singleton fetuses were exposed to normoxia (n = 6) or hypoxia (10% inspired O2 , n = 9) for the last third of gestation (105-138 days of gestation (dG); term ∼145 dG) in isobaric chambers. At 138 dG, isolated hearts were studied using a Langendorff preparation. We calculated basal intrinsic FHRV (iFHRV) indices reflecting iFHRV's variability, predictability, temporal symmetry, fractality and chaotic behaviour, from the systolic peaks within 15 min segments in each heart. Significance was assumed at P < 0.05. Hearts of fetuses isolated from hypoxic pregnancy showed approximately 4-fold increases in the Grid transformation as well as the AND similarity index (sgridAND) and a 4-fold reduction in the scale-dependent Lyapunov exponent slope. We also detected a 2-fold reduction in the Recurrence quantification analysis, percentage of laminarity (pL) and recurrences, maximum and average diagonal line (dlmax, dlmean) and the Multiscale time irreversibility asymmetry index. The iHRV measures dlmax, dlmean, pL and sgridAND correlated with left ventricular end-diastolic pressure across both groups (average R2 = 0.38 ± 0.03). This is the first evidence that iHRV originates in fetal life and that chronic fetal hypoxia significantly alters it. Isolated fetal hearts from hypoxic pregnancy exhibit a time scale-dependent higher complexity in iFHRV.
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Affiliation(s)
- Martin G Frasch
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, USA
| | - Christophe L Herry
- Dynamical Analysis Laboratory, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Youguo Niu
- Department of Physiology Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Dino A Giussani
- Department of Physiology Development & Neuroscience, University of Cambridge, Cambridge, UK
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Kahankova R, Martinek R, Jaros R, Behbehani K, Matonia A, Jezewski M, Behar JA. A Review of Signal Processing Techniques for Non-Invasive Fetal Electrocardiography. IEEE Rev Biomed Eng 2019; 13:51-73. [PMID: 31478873 DOI: 10.1109/rbme.2019.2938061] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Fetal electrocardiography (fECG) is a promising alternative to cardiotocography continuous fetal monitoring. Robust extraction of the fetal signal from the abdominal mixture of maternal and fetal electrocardiograms presents the greatest challenge to effective fECG monitoring. This is mainly due to the low amplitude of the fetal versus maternal electrocardiogram and to the non-stationarity of the recorded signals. In this review, we highlight key developments in advanced signal processing algorithms for non-invasive fECG extraction and the available open access resources (databases and source code). In particular, we highlight the advantages and limitations of these algorithms as well as key parameters that must be set to ensure their optimal performance. Improving or combining the current or developing new advanced signal processing methods may enable morphological analysis of the fetal electrocardiogram, which today is only possible using the invasive scalp electrocardiography method.
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Frasch MG, Lobmaier SM, Stampalija T, Desplats P, Pallarés ME, Pastor V, Brocco MA, Wu HT, Schulkin J, Herry CL, Seely AJE, Metz GAS, Louzoun Y, Antonelli MC. Non-invasive biomarkers of fetal brain development reflecting prenatal stress: An integrative multi-scale multi-species perspective on data collection and analysis. Neurosci Biobehav Rev 2018; 117:165-183. [PMID: 29859198 DOI: 10.1016/j.neubiorev.2018.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/09/2018] [Accepted: 05/25/2018] [Indexed: 02/07/2023]
Abstract
Prenatal stress (PS) impacts early postnatal behavioural and cognitive development. This process of 'fetal programming' is mediated by the effects of the prenatal experience on the developing hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). We derive a multi-scale multi-species approach to devising preclinical and clinical studies to identify early non-invasively available pre- and postnatal biomarkers of PS. The multiple scales include brain epigenome, metabolome, microbiome and the ANS activity gauged via an array of advanced non-invasively obtainable properties of fetal heart rate fluctuations. The proposed framework has the potential to reveal mechanistic links between maternal stress during pregnancy and changes across these physiological scales. Such biomarkers may hence be useful as early and non-invasive predictors of neurodevelopmental trajectories influenced by the PS as well as follow-up indicators of success of therapeutic interventions to correct such altered neurodevelopmental trajectories. PS studies must be conducted on multiple scales derived from concerted observations in multiple animal models and human cohorts performed in an interactive and iterative manner and deploying machine learning for data synthesis, identification and validation of the best non-invasive detection and follow-up biomarkers, a prerequisite for designing effective therapeutic interventions.
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Affiliation(s)
- Martin G Frasch
- Department of Obstetrics and Gynecology, University of Washington, Seattle, USA.
| | - Silvia M Lobmaier
- Frauenklinik und Poliklinik, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Tamara Stampalija
- Unit of Fetal Medicine and Prenatal Diagnosis, Institute for Mother and Child Health IRCCS Burlo Garofolo, Trieste, Italy
| | - Paula Desplats
- University of California, Departments of Neurosciences and Pathology, San Diego, USA
| | - María Eugenia Pallarés
- Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis", Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Verónica Pastor
- Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis", Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Marcela A Brocco
- Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín - Consejo Nacional de Investigaciones Científicas y Técnicas (UNSAM-CONICET), San Martín, Buenos Aires, Argentina
| | - Hau-Tieng Wu
- Department of Mathematics and Department of Statistical Science, Duke University, Durham, NC, USA; Mathematics Division, National Center for Theoretical Sciences, Taipei, Taiwan
| | - Jay Schulkin
- Department of Obstetrics and Gynecology, University of Washington, Seattle, USA
| | | | | | - Gerlinde A S Metz
- Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Yoram Louzoun
- Bar-Ilan University, Department of Applied Mathematics, Israel
| | - Marta C Antonelli
- Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis", Facultad de Medicina, Universidad de Buenos Aires, Argentina
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Shen C, Frasch MG, Wu HT, Herry CL, Cao M, Desrochers A, Fecteau G, Burns P. Non-invasive acquisition of fetal ECG from the maternal xyphoid process: a feasibility study in pregnant sheep and a call for open data sets. Physiol Meas 2018; 39:035005. [PMID: 29369821 DOI: 10.1088/1361-6579/aaaaa4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The utility of fetal heart rate (FHR) monitoring can only be achieved with an acquisition sampling rate that preserves the underlying physiological information on the millisecond time scale (1000 Hz rather than 4 Hz). For such acquisition, fetal ECG (fECG) is required, rather than the ultrasound to derive FHR. We tested one recently developed algorithm, SAVER, and two widely applied algorithms to extract fECG from a single-channel maternal ECG signal recorded over the xyphoid process rather than the routine abdominal signal. APPROACH At 126dG, ECG was attached to near-term ewe and fetal shoulders, manubrium and xyphoid processes (n = 12). fECG served as the ground-truth to which the fetal ECG signal extracted from the simultaneously-acquired maternal ECG was compared. All fetuses were in good health during surgery (pH 7.29 ± 0.03, pO2 33.2 ± 8.4, pCO2 56.0 ± 7.8, O2Sat 78.3 ± 7.6, lactate 2.8 ± 0.6, BE -0.3 ± 2.4). MAIN RESULT In all animals, single lead fECG extraction algorithm could not extract fECG from the maternal ECG signal over the xyphoid process with the F1 less than 50%. SIGNIFICANCE The applied fECG extraction algorithms might be unsuitable for the maternal ECG signal over the xyphoid process, or the latter does not contain strong enough fECG signal, although the lead is near the mother's abdomen. Fetal sheep model is widely used to mimic various fetal conditions, yet ECG recordings in a public data set form are not available to test the predictive ability of fECG and FHR. We are making this data set openly available to other researchers to foster non-invasive fECG acquisition in this animal model.
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Affiliation(s)
- C Shen
- Mathematics, Duke University, Durham NC, United States of America
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Frasch MG, Baier CJ, Antonelli MC, Metz GAS. Perinatal Psychoneuroimmunology: Protocols for the Study of Prenatal Stress and Its Effects on Fetal and Postnatal Brain Development. Methods Mol Biol 2018; 1781:353-376. [PMID: 29705857 DOI: 10.1007/978-1-4939-7828-1_19] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Prenatal stress (PS) impacts early behavioral, neuroimmune, and cognitive development. Pregnant rat models have been very valuable in examining the mechanisms of such fetal programming. A newer pregnant sheep model of maternal stress offers the unique advantages of chronic in utero monitoring and manipulation. This chapter presents the techniques used to model single and multigenerational stress exposures and their pleiotropic effects on the offspring.
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Affiliation(s)
- Martin G Frasch
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, USA.
| | - Carlos J Baier
- Departamento de Biología, Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bioquímica y Farmacia (DBByF), Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Marta C Antonelli
- Facultad de Medicina, Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis", Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gerlinde A S Metz
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
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Frasch MG, Boylan GB, Wu HT, Devane D. Commentary: Computerised interpretation of fetal heart rate during labour (INFANT): a randomised controlled trial. Front Physiol 2017; 8:721. [PMID: 29033845 PMCID: PMC5625115 DOI: 10.3389/fphys.2017.00721] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/06/2017] [Indexed: 12/31/2022] Open
Affiliation(s)
- Martin G. Frasch
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, United States
| | - Geraldine B. Boylan
- Irish Centre for Fetal and Neonatal Translational Research, Cork, Ireland
- Department of Paediatrics and Child Health, University College Cork, Cork, Ireland
| | - Hau-tieng Wu
- Department of Mathematics and Department of Statistical Science, Duke University, Durham, NC, United States
| | - Declan Devane
- Irish Centre for Fetal and Neonatal Translational Research, Cork, Ireland
- School of Nursing and Midwifery, NUI Galway, Galway, Ireland
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Al-Angari HM, Kimura Y, Hadjileontiadis LJ, Khandoker AH. A Hybrid EMD-Kurtosis Method for Estimating Fetal Heart Rate from Continuous Doppler Signals. Front Physiol 2017; 8:641. [PMID: 28912727 PMCID: PMC5582307 DOI: 10.3389/fphys.2017.00641] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 08/15/2017] [Indexed: 11/13/2022] Open
Abstract
Monitoring of fetal heart rate (FHR) is an important measure of fetal wellbeing during the months of pregnancy. Previous works on estimating FHR variability from Doppler ultrasound (DUS) signal mainly through autocorrelation analysis showed low accuracy when compared with heart rate variability (HRV) computed from fetal electrocardiography (fECG). In this work, we proposed a method based on empirical mode decomposition (EMD) and the kurtosis statistics to estimate FHR and its variability from DUS. Comparison between estimated beat-to-beat intervals using the proposed method and the autocorrelation function (AF) with respect to RR intervals computed from fECG as the ground truth was done on DUS signals from 44 pregnant mothers in the early (20 cases) and late (24 cases) gestational weeks. The new EMD-kurtosis method showed significant lower error in estimating the number of beats in the early group (EMD-kurtosis: 2.2% vs. AF: 8.5%, p < 0.01, root mean squared error) and the late group (EMD-kurtosis: 2.9% vs. AF: 6.2%). The EMD-kurtosis method was also found to be better in estimating mean beat-to-beat with an average difference of 1.6 ms from true mean RR compared to 19.3 ms by using the AF method. However, the EMD-kurtosis performed worse than AF in estimating SNDD and RMSSD. The proposed EMD-kurtosis method is more robust than AF in low signal-to-noise ratio cases and can be used in a hybrid system to estimate beat-to-beat intervals from DUS. Further analysis to reduce the estimated beat-to-beat variability from the EMD-kurtosis method is needed.
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Affiliation(s)
- Haitham M Al-Angari
- Department of Biomedical Engineering, Khalifa University of Science and TechnologyAbu Dhabi, United Arab Emirates
| | | | - Leontios J Hadjileontiadis
- Department of Electrical and Computer Engineering, Khalifa University of Science and TechnologyAbu Dhabi, United Arab Emirates.,Department of Electrical and Computer Engineering, Aristotle University of ThessalonikiThessaloniki, Greece
| | - Ahsan H Khandoker
- Department of Biomedical Engineering, Khalifa University of Science and TechnologyAbu Dhabi, United Arab Emirates
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14
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Li R, Frasch MG, Wu HT. Efficient Fetal-Maternal ECG Signal Separation from Two Channel Maternal Abdominal ECG via Diffusion-Based Channel Selection. Front Physiol 2017; 8:277. [PMID: 28559848 PMCID: PMC5432652 DOI: 10.3389/fphys.2017.00277] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 04/18/2017] [Indexed: 12/19/2022] Open
Abstract
There is a need for affordable, widely deployable maternal-fetal ECG monitors to improve maternal and fetal health during pregnancy and delivery. Based on the diffusion-based channel selection, here we present the mathematical formalism and clinical validation of an algorithm capable of accurate separation of maternal and fetal ECG from a two channel signal acquired over maternal abdomen. The proposed algorithm is the first algorithm, to the best of the authors' knowledge, focusing on the fetal ECG analysis based on two channel maternal abdominal ECG signal, and we apply it to two publicly available databases, the PhysioNet non-invasive fECG database (adfecgdb) and the 2013 PhysioNet/Computing in Cardiology Challenge (CinC2013), to validate the algorithm. The state-of-the-art results are achieved when compared with other available algorithms. Particularly, the F1 score for the R peak detection achieves 99.3% for the adfecgdb and 87.93% for the CinC2013, and the mean absolute error for the estimated R peak locations is 4.53 ms for the adfecgdb and 6.21 ms for the CinC2013. The method has the potential to be applied to other fetal cardiogenic signals, including cardiac doppler signals.
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Affiliation(s)
- Ruilin Li
- Department of Mathematics, University of TorontoToronto, ON, Canada
| | - Martin G Frasch
- Department of Obstetrics and Gynecology, University of WashingtonSeattle, USA
| | - Hau-Tieng Wu
- Department of Mathematics, University of TorontoToronto, ON, Canada.,Mathematics Division, National Center for Theoretical SciencesTaipei, Taiwan
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15
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Frasch MG, Szynkaruk M, Prout AP, Nygard K, Cao M, Veldhuizen R, Hammond R, Richardson BS. Decreased neuroinflammation correlates to higher vagus nerve activity fluctuations in near-term ovine fetuses: a case for the afferent cholinergic anti-inflammatory pathway? J Neuroinflammation 2016; 13:103. [PMID: 27165310 PMCID: PMC4894374 DOI: 10.1186/s12974-016-0567-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/02/2016] [Indexed: 12/18/2022] Open
Abstract
Background Neuroinflammation in utero may contribute to brain injury resulting in life-long neurological disabilities. The pivotal role of the efferent cholinergic anti-inflammatory pathway (CAP) in controlling inflammation, e.g., by inhibiting the HMGB1 release, via the macrophages’ α7 nicotinic acetylcholine receptor (α7nAChR) has been described in adults, but its importance in the fetus is unknown. Moreover, it is unknown whether CAP may also exert anti-inflammatory effects on the brain via the anatomically predominant afferent component of the vagus nerve. Methods We measured microglial activation in the ovine fetal brain near term 24 h after the umbilical cord occlusions mimicking human labor versus controls (no occlusions) by quantifying HMGB1 nucleus-to-cytosol translocation in the Iba1+ and α7nAChR+ microglia. Based on multiple clinical studies in adults and our own work in fetal autonomic nervous system, we gauged the degree of CAP activity in vivo using heart rate variability measure RMSSD that reflects fluctuations in vagus nerve activity. Results RMSSD correlated to corresponding plasma IL-1β levels at R = 0.57 (p = 0.02, n = 17) and to white matter microglia cell counts at R = −0.89 (p = 0.03). The insult increased the HMGB1 translocation in α7nAChR+ microglia in a brain region-dependent manner (p < 0.001). In parallel, RMSSD at 1 h post insult correlated with cytosolic HMGB1 of thalamic microglia (R = −0.94, p = 0.005), and RMSSD at pH nadir correlated with microglial α7nAChR in the white matter (R = 0.83, p = 0.04). Overall, higher RMSSD values correlated with lower HMGB1 translocation and higher α7nAChR intensity per area in a brain region-specific manner. Conclusions Afferent fetal CAP may translate increased vagal cholinergic signaling into suppression of cerebral inflammation in response to near-term hypoxic acidemia as might occur during labor. Our findings suggest a new control mechanism of fetal neuroinflammation via the vagus nerve, providing novel possibilities for its non-invasive monitoring in utero and for targeted treatment. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0567-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- M G Frasch
- Department of Obstetrics and Gynaecology, CHU Ste-Justine Research Centre, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada. .,Department of Neurosciences, CHU Ste-Justine Research Centre, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada. .,Animal Reproduction Research Centre (CRRA), Faculty of Veterinary Medicine, Université de Montréal, Montréal, QC, Canada. .,Department of Obstetrics and Gynaecology, Lawson Health Research Institute, University of Western Ontario, London, ON, Canada. .,Department of Obstetrics and Gynecology, University of Washington, 1959 NE Pacific St, Box 356460, Seattle, WA, 98195, USA.
| | - M Szynkaruk
- Department of Obstetrics and Gynaecology, Lawson Health Research Institute, University of Western Ontario, London, ON, Canada
| | - A P Prout
- Department of Obstetrics and Gynaecology, Lawson Health Research Institute, University of Western Ontario, London, ON, Canada
| | - K Nygard
- Microscopy Imaging@Biotron, University of Western Ontario, London, ON, Canada
| | - M Cao
- Department of Obstetrics and Gynaecology, CHU Ste-Justine Research Centre, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, CHU Ste-Justine Research Centre, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - R Veldhuizen
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - R Hammond
- Department of Pathology, University of Western Ontario, London, ON, Canada
| | - B S Richardson
- Department of Obstetrics and Gynaecology, Lawson Health Research Institute, University of Western Ontario, London, ON, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
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16
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Frasch MG. Editorial: Perinatology in the Era of Big Data and Nanoparticles. Front Pediatr 2015; 3:95. [PMID: 26594641 PMCID: PMC4633508 DOI: 10.3389/fped.2015.00095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/22/2015] [Indexed: 11/13/2022] Open
Affiliation(s)
- Martin G Frasch
- Department of Obstetrics and Gynecology, CHU Sainte-Justine Centre de Recherche, Université de Montréal , Montreal, QC , Canada ; Department of Neurosciences, CHU Sainte-Justine Centre de Recherche, Université de Montréal , Montreal, QC , Canada
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