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Schipper F, van Sloun RJG, Grassi A, Brouwer J, van Meulen F, Overeem S, Fonseca P. Maximum a posteriori detection of heartbeats from a chest-worn accelerometer. Physiol Meas 2024; 45:035009. [PMID: 38430565 DOI: 10.1088/1361-6579/ad2f5e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 03/01/2024] [Indexed: 03/04/2024]
Abstract
Objective. Unobtrusive long-term monitoring of cardiac parameters is important in a wide variety of clinical applications, such as the assesment of acute illness severity and unobtrusive sleep monitoring. Here we determined the accuracy and robustness of heartbeat detection by an accelerometer worn on the chest.Approach. We performed overnight recordings in 147 individuals (69 female, 78 male) referred to two sleep centers. Two methods for heartbeat detection in the acceleration signal were compared: one previously described approach, based on local periodicity, and a novel extended method incorporating maximumaposterioriestimation and a Markov decision process to approach an optimal solution.Main results. The maximumaposterioriestimation significantly improved performance, with a mean absolute error for the estimation of inter-beat intervals of only 3.5 ms, and 95% limits of agreement of -1.7 to +1.0 beats per minute for heartrate measurement. Performance held during posture changes and was only weakly affected by the presence of sleep disorders and demographic factors.Significance. The new method may enable the use of a chest-worn accelerometer in a variety of applications such as ambulatory sleep staging and in-patient monitoring.
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Affiliation(s)
- Fons Schipper
- Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Philips Research, Philips, Eindhoven, The Netherlands
| | - Ruud J G van Sloun
- Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Philips Research, Philips, Eindhoven, The Netherlands
| | - Angela Grassi
- Philips Research, Philips, Eindhoven, The Netherlands
| | - Jan Brouwer
- Philips Research, Philips, Eindhoven, The Netherlands
| | - Fokke van Meulen
- Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Kempenhaeghe Center for Sleep Medicine, Heeze, The Netherlands
| | - Sebastiaan Overeem
- Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Kempenhaeghe Center for Sleep Medicine, Heeze, The Netherlands
| | - Pedro Fonseca
- Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Philips Research, Philips, Eindhoven, The Netherlands
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Schipper F, van Sloun RJG, Grassi A, Derkx R, Overeem S, Fonseca P. Estimation of respiratory rate and effort from a chest-worn accelerometer using constrained and recursive principal component analysis. Physiol Meas 2021; 42. [PMID: 33739305 DOI: 10.1088/1361-6579/abf01f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 03/18/2021] [Indexed: 11/11/2022]
Abstract
Objective. Measurement of respiratory rate and effort is useful in various applications, such as the diagnosis of sleep apnea and early detection of patient deterioration in medical conditions, such as infections. A chest-worn accelerometer may be an easy and non-intrusive method, provided it is accurate and robust. We investigate the use of a novel method that can perform under realistic sleeping conditions such as variable sensor positions and body posture.Approach. Twenty subjects (aged 46-65 years) wore an accelerometer on the chest and a respiratory impedance plethysmography band as a reference. The subjects underwent an experimental protocol lasting approximately 90 min, under various postures and with different sensor positions. We used a novel, constrained, and recursive form of principal component analysis (PCA) to estimate the respiratory effort signal robustly. To obtain an estimate for the respiratory rate, first, multiple estimates were aggregated into a single frequency. Subsequently, a quality index was determined, such that unreliable estimates could be identified, and a trade-off could be made between coverage (percentage of time that the quality index is above a threshold) and limits of agreement.Main results. Results were determined over all recorded data, including changes in sensor position and posture. For respiratory effort, it was found that recursive and constrained computation of PCA reduced the estimation error significantly. For respiratory rate, a relation between coverage and limits of agreement was determined. If a minimum coverage of 80% was required, the limits of agreement could be kept below 1.45 breaths per minute. If the limits of agreement were constrained to 0.2 breaths per minute, a mean coverage of 5% was still attainable.Significance. We have shown that chest-worn accelerometery can be a robust and accurate method for measurement of respiratory features under realistic conditions.
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Affiliation(s)
- Fons Schipper
- Philips Research, Eindhoven, The Netherlands.,Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Ruud J G van Sloun
- Philips Research, Eindhoven, The Netherlands.,Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | | | - Rene Derkx
- Philips Research, Eindhoven, The Netherlands
| | - Sebastiaan Overeem
- Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Sleep Medicine Center, Kempenhaeghe, Heeze, The Netherlands
| | - Pedro Fonseca
- Philips Research, Eindhoven, The Netherlands.,Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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Eerikainen LM, Bonomi AG, Schipper F, Dekker LRC, de Morree HM, Vullings R, Aarts RM. Detecting Atrial Fibrillation and Atrial Flutter in Daily Life Using Photoplethysmography Data. IEEE J Biomed Health Inform 2019; 24:1610-1618. [PMID: 31689222 DOI: 10.1109/jbhi.2019.2950574] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Photoplethysmography (PPG) enables unobtrusive heart rate monitoring, which can be used in wrist-worn applications. Its potential for detecting atrial fibrillation (AF) has been recently presented. Besides AF, another cardiac arrhythmia increasing stroke risk and requiring treatment is atrial flutter (AFL). Currently, the knowledge about AFL detection with PPG is limited. The objective of our study was to develop a model that classifies AF, AFL, and sinus rhythm with or without premature beats from PPG and acceleration data measured at the wrist in daily life. METHODS A dataset of 40 patients was collected by measuring PPG and accelerometer data, as well as electrocardiogram as a reference, during 24-hour monitoring. The dataset was split into 75%-25% for training and testing a Random Forest (RF) model, which combines features from PPG, inter-pulse intervals (IPI), and accelerometer data, to classify AF, AFL, and other rhythms. The performance was compared to an AF detection algorithm combining traditional IPI features for determining the robustness of the accuracy in presence of AFL. RESULTS The RF model classified AF/AFL/other with sensitivity and specificity of 97.6/84.5/98.1% and 98.2/99.7/92.8%, respectively. The results with the IPI-based AF classifier showed that the majority of false detections were caused by AFL. CONCLUSION The PPG signal contains information to classify AFL in the presence of AF, sinus rhythm, or sinus rhythm with premature contractions. SIGNIFICANCE PPG could indicate presence of AFL, not only AF.
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Eerikäinen LM, Bonomi AG, Schipper F, Dekker LRC, Vullings R, de Morree HM, Aarts RM. Comparison between electrocardiogram- and photoplethysmogram-derived features for atrial fibrillation detection in free-living conditions. Physiol Meas 2018; 39:084001. [PMID: 29995641 DOI: 10.1088/1361-6579/aad2c0] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Atrial fibrillation (AF) is the most commonly experienced arrhythmia and it increases the risk of stroke and heart failure. The challenge in detecting the presence of AF is the occasional and asymptomatic manifestation of the condition. Long-term monitoring can increase the sensitivity of detecting intermittent AF episodes, however it is either cumbersome or invasive and costly with electrocardiography (ECG). Photoplethysmography (PPG) is an unobtrusive measuring modality enabling heart rate monitoring, and promising results have been presented in detecting AF. However, there is still limited knowledge about the applicability of the PPG solutions in free-living conditions. The aim of this study was to compare the inter-beat interval derived features for AF detection between ECG and wrist-worn PPG in daily life. APPROACH The data consisted of 24 h ECG, PPG, and accelerometer measurements from 27 patients (eight AF, 19 non-AF). In total, seven features (Shannon entropy, root mean square of successive differences (RMSSD), normalized RMSSD, pNN40, pNN70, sample entropy, and coefficient of sample entropy (CosEn)) were compared. Body movement was measured with the accelerometer and used with three different thresholds to exclude PPG segments affected by movement. MAIN RESULTS CosEn resulted as the best performing feature from ECG with Cohens kappa 0.95. When the strictest movement threshold was applied, the same performance was obtained with PPG (kappa = 0.96). In addition, pNN40 and pNN70 reached similar results with the same threshold (kappa = 0.95 and 0.94), but were more robust with respect to movement artefacts. The coverage of PPG was 24.0%-57.6% depending on the movement threshold compared to 92.1% of ECG. SIGNIFICANCE The inter-beat interval features derived from PPG are equivalent to the ones from ECG for AF detection. Movement artefacts substantially worsen PPG-based AF monitoring in free-living conditions, therefore monitoring coverage needs to be carefully selected. Wrist-worn PPG still provides a promising technology for long-term AF monitoring.
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Affiliation(s)
- Linda M Eerikäinen
- Department of Electrical Engineering, Eindhoven University of Technology, 5612 AZ, Eindhoven, Netherlands. Philips Research, Eindhoven, Netherlands
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Bonomi AG, Schipper F, Eerikäinen LM, Margarito J, van Dinther R, Muesch G, de Morree HM, Aarts RM, Babaeizadeh S, McManus DD, Dekker LR. Atrial Fibrillation Detection Using a Novel Cardiac Ambulatory Monitor Based on Photo-Plethysmography at the Wrist. J Am Heart Assoc 2018; 7:e009351. [PMID: 30371247 PMCID: PMC6201454 DOI: 10.1161/jaha.118.009351] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/15/2018] [Indexed: 01/01/2023]
Abstract
Background Long-term continuous cardiac monitoring would aid in the early diagnosis and management of atrial fibrillation ( AF ). This study examined the accuracy of a novel approach for AF detection using photo-plethysmography signals measured from a wrist-based wearable device. Methods and Results ECG and contemporaneous pulse data were collected from 2 cohorts of AF patients: AF patients (n=20) undergoing electrical cardioversion ( ECV ) and AF patients (n=40) that were prescribed for 24 hours ECG Holter in outpatient settings ( HOL ). Photo-plethysmography and acceleration data were collected at the wrist and processed to determine the inter-pulse interval and discard inter-pulse intervals in presence of motion artifacts. A Markov model was deployed to assess the probability of AF given irregular pattern in inter-pulse interval sequences. The AF detection algorithm was evaluated against clinical rhythm annotations of AF based on ECG interpretation. Photo-plethysmography recordings from apparently healthy volunteers (n=120) were used to establish the false positive AF detection rate of the algorithm. A total of 42 and 855 hours (AF: 21 and 323 hours) of photo-plethysmography data were recorded in the ECV and HOL cohorts, respectively. AF was detected with >96% accuracy ( ECV, sensitivity=97%; HOL , sensitivity=93%; both with specificity=100%). Because of motion artifacts, the algorithm did not provide AF classification for 44±16% of the monitoring period in the HOL group. In healthy controls, the algorithm demonstrated a <0.2% false positive AF detection rate. Conclusions A novel AF detection algorithm using pulse data from a wrist-wearable device can accurately discriminate rhythm irregularities caused by AF from normal rhythm.
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Affiliation(s)
| | | | - Linda M. Eerikäinen
- Philips ResearchEindhovenThe Netherlands
- Department of Electrical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
| | | | | | | | | | - Ronald M. Aarts
- Philips ResearchEindhovenThe Netherlands
- Department of Electrical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
| | | | - David D. McManus
- Cardiology DivisionDepartment of MedicineUniversity of Massachusetts Medical SchoolWorcesterMA
| | - Lukas R.C. Dekker
- Department of Electrical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
- Department of CardiologyCatharina HospitalEindhovenThe Netherlands
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Hamley IW, Castelletto V, Floudas G, Schipper F. Templated Crystallization from Oriented Gyroid and Hexagonal Melt Phases in a Diblock Copolymer. Macromolecules 2002. [DOI: 10.1021/ma0207069] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- I. W. Hamley
- Department of Chemistry, University of Leeds, Leeds LS2 9JT, UK; Department of Physics, University of Ioannina, 45 110 Ioannina, Greece, and Institute of Biomedical Research (IBR-FORTH), Ioannina, Greece; and Foundation for Research and Technology-Hellas, I.E.S.L., 711 10 Heraklion, Crete, Greece
| | - V. Castelletto
- Department of Chemistry, University of Leeds, Leeds LS2 9JT, UK; Department of Physics, University of Ioannina, 45 110 Ioannina, Greece, and Institute of Biomedical Research (IBR-FORTH), Ioannina, Greece; and Foundation for Research and Technology-Hellas, I.E.S.L., 711 10 Heraklion, Crete, Greece
| | - G. Floudas
- Department of Chemistry, University of Leeds, Leeds LS2 9JT, UK; Department of Physics, University of Ioannina, 45 110 Ioannina, Greece, and Institute of Biomedical Research (IBR-FORTH), Ioannina, Greece; and Foundation for Research and Technology-Hellas, I.E.S.L., 711 10 Heraklion, Crete, Greece
| | - F. Schipper
- Department of Chemistry, University of Leeds, Leeds LS2 9JT, UK; Department of Physics, University of Ioannina, 45 110 Ioannina, Greece, and Institute of Biomedical Research (IBR-FORTH), Ioannina, Greece; and Foundation for Research and Technology-Hellas, I.E.S.L., 711 10 Heraklion, Crete, Greece
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Abstract
For more than 10 years umbilical cord blood (UCB) has been used as an alternative source of hematopoietic stem cells for allogeneic transplantation. Although the clinical results are encouraging, UCB is associated with delayed engraftment. To address these issues we have used the NOD/SCID mouse model to study the engraftment potential of cord blood cells in more detail, to assess the engraftment potential of expanded megakaryocytic progenitor cells, and to study the effect of co-transplantation of mesenchymal stem cells on engraftment.
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Affiliation(s)
- W E Fibbe
- Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands
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Floudas G, Vazaiou B, Schipper F, Ulrich R, Wiesner U, Iatrou H, Hadjichristidis N. Poly(ethylene oxide-b-isoprene) Diblock Copolymer Phase Diagram. Macromolecules 2001. [DOI: 10.1021/ma001957p] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- G. Floudas
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FO.R.T.H.), P.O. Box 1527, 711 10 Heraklion, Crete, Greece; Department of Chemistry, University of Athens, Zografou 15771, Athens, Greece; and Max-Planck Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
| | - B. Vazaiou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FO.R.T.H.), P.O. Box 1527, 711 10 Heraklion, Crete, Greece; Department of Chemistry, University of Athens, Zografou 15771, Athens, Greece; and Max-Planck Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
| | - F. Schipper
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FO.R.T.H.), P.O. Box 1527, 711 10 Heraklion, Crete, Greece; Department of Chemistry, University of Athens, Zografou 15771, Athens, Greece; and Max-Planck Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
| | - R. Ulrich
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FO.R.T.H.), P.O. Box 1527, 711 10 Heraklion, Crete, Greece; Department of Chemistry, University of Athens, Zografou 15771, Athens, Greece; and Max-Planck Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
| | - U. Wiesner
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FO.R.T.H.), P.O. Box 1527, 711 10 Heraklion, Crete, Greece; Department of Chemistry, University of Athens, Zografou 15771, Athens, Greece; and Max-Planck Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
| | - H. Iatrou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FO.R.T.H.), P.O. Box 1527, 711 10 Heraklion, Crete, Greece; Department of Chemistry, University of Athens, Zografou 15771, Athens, Greece; and Max-Planck Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
| | - N. Hadjichristidis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FO.R.T.H.), P.O. Box 1527, 711 10 Heraklion, Crete, Greece; Department of Chemistry, University of Athens, Zografou 15771, Athens, Greece; and Max-Planck Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
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Vaessen LM, Schipper F, Knoop C, Claas FH, Weimar W. Inverted V delta 1/V delta 2 ratio within the T cell receptor (TCR)-gamma delta T cell population in peripheral blood of heart transplant recipients. Clin Exp Immunol 1996; 103:119-24. [PMID: 8565270 PMCID: PMC2200309 DOI: 10.1046/j.1365-2249.1996.909604.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We investigated the levels of TCR-gamma delta T cells and their subpopulations V delta 1 and V delta 2 in the peripheral blood lymphocytes (PBL) of 28 heart transplant (HTx) patients. Patients (n = 10) receiving cyclosporin A (CsA) for treatment of a nephrotic syndrome (NS) and 10 healthy individuals served as controls. There was no difference in levels of TCR-gamma delta T cells between the different groups. However, an elevated proportion of V delta 1+ gamma delta T cells was found in the PBL of HTx patients, especially when these cells were present in their graft-infiltrating lymphocyte (GIL) cultures. V delta 1+ gamma delta T cells of HTx patients showed normal expression of CD45RO and lacked the activation markers CD25 and HLA-DR. After expanding in IL-2-containing medium, PBL cultures of HTx patients more often were dominated by V delta 1 cells than PBL cultures of controls, in which V delta 2 cells were predominantly grown. The aberrant composition of the TCR-gamma delta population in HTx patients was not a result of immunosuppressive medication, since the proportion V delta 1+ gamma delta T cells was normal in the PBL of the NS patients receiving a similar dose of CsA. It is postulated that long-term antigenic stimulation by the graft, at low level, might be responsible for the altered composition of the gamma delta pool in the HTx patients. Since no donor HLA-specific gamma delta T cells have been detected, other ligands, such as heat shock proteins, may be involved.
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Affiliation(s)
- L M Vaessen
- Department of Internal Medicine I, University Hospital Rotterdam-Dijkzigt, The Netherlands
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