1
|
Carrillo AE, Akerman AP, Notley SR, Herry CL, Seely AJE, Ruzicka M, Boulay P, Kenny GP. Cardiac autonomic modulation in individuals with controlled and uncomplicated hypertension during exercise-heat stress. Appl Physiol Nutr Metab 2023; 48:863-869. [PMID: 37556854 DOI: 10.1139/apnm-2023-0173] [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] [Indexed: 08/11/2023]
Abstract
TAKE-HOME MESSAGE During short bouts of light-to-vigorous exercise in the heat, controlled and uncomplicated hypertension did not significantly modulate HRV in physically active individuals. These findings can be used to refine guidance on use of exercise for hypertension management in the heat.
Collapse
Affiliation(s)
- Andres E Carrillo
- Department of Exercise Science, School of Health Sciences, Chatham University, Pittsburgh, PA 15232, USA
| | - Ashley P Akerman
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Andrew J E Seely
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Division of Thoracic Surgery and Department of Critical Care Medicine, Ottawa Hospital, Ottawa, ON, Canada
| | - Marcel Ruzicka
- Hypertension Program, Division of Nephrology, University of Ottawa, Ottawa, ON, Canada
| | - Pierre Boulay
- Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| |
Collapse
|
2
|
Martin S, Du Pont-Thibodeau G, Seely AJE, Emeriaud G, Herry CL, Recher M, Lacroix J, Ducharme-Crevier L. Heart Rate Variability in Children with Moderate and Severe Traumatic Brain Injury: A Prospective Observational Study. J Pediatr Intensive Care 2022. [DOI: 10.1055/s-0042-1759877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AbstractThe aim of this study was to assess the feasibility of continuous monitoring of heart rate variability (HRV) in children with traumatic brain injury (TBI) hospitalized in a pediatric intensive care unit (PICU) and collect preliminary data on the association between HRV, neurological outcome, and complications. This is a prospective observational cohort study in a tertiary academic PICU. Children admitted to the PICU ≤24 hours after moderate or severe TBI were included in the study. Children suspected of being brain dead at PICU entry or with a pacemaker were excluded. Children underwent continuous monitoring of electrocardiographic (ECG) waveforms over 7 days post-TBI. HRV analysis was performed retrospectively, using a standardized, validated HRV analysis software (CIMVA). The occurrence of medical complications (“event”: intracranial hypertension, cerebral hypoperfusion, seizure, and cardiac arrest) was prospectively documented. Outcome of children 6 months post-TBI was assessed using the Glasgow Outcome Scale – Extended Pediatric (GOS-E Peds). Fifteen patients were included over a 20-month period. Thirteen patients had ECG recordings available and 4 had >20% of missing ECG data. When ECG was available, HRV calculation was feasible (average 88%; range 70–97%). Significant decrease in overall HRV coefficient of variation and Poincaré SD2 (p < 0.05) at 6 hours post–PICU admission was associated with an unfavorable outcome (defined as GOS-E Peds ≥ 3, or a deterioration of ≥2 points over baseline score). Several HRV metrics exhibited significant and nonsignificant variation in HRV during event. This study demonstrates that it is feasible to monitor HRV in the PICU provided ECG data are available; however, missing ECG data are not uncommon. These preliminary data suggest that altered HRV is associated with unfavorable neurological outcome and in-hospital medical complications. Larger prospective studies are needed to confirm these findings and to explore if HRV offers reliable and clinically useful prediction data that may help clinical decision making.
Collapse
Affiliation(s)
- Sophie Martin
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada
| | - Geneviève Du Pont-Thibodeau
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada
| | - Andrew J. E. Seely
- Thoracic Surgery & Critical Care Medicine, The Ottawa Hospital, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Guillaume Emeriaud
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada
| | | | - Morgan Recher
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada
| | - Jacques Lacroix
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada
| | - Laurence Ducharme-Crevier
- Division of Pediatric Critical Care Medicine, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada
| |
Collapse
|
3
|
De Barros JA, Macartney MJ, Peoples GE, Notley SR, Herry CL, Kenny GP. Effects of sex and wet-bulb globe temperature on heart rate variability during prolonged moderate-intensity exercise: A secondary analysis. Appl Physiol Nutr Metab 2022; 47:725-736. [PMID: 35290752 DOI: 10.1139/apnm-2022-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sex-differences in heart rate (HR) and heart rate variability (HRV), a surrogate of cardiac autonomic modulation, are evident during rest and exercise in young healthy individuals. However, it remains unclear whether sex impacts HRV during prolonged exercise at differing levels of environmental heat stress. Therefore, we completed a secondary analysis upon the effects of sex and wet-bulb globe temperature (WBGT) on HR and HRV during prolonged exercise. To achieve this, HR and HRV were assessed in non-endurance-trained and non-heat-acclimatized healthy men (n=19) and women (n=15) aged 18-45 years during 180-min treadmill walking at a moderate metabolic rate (200 W/m2: equivalent to ~35% peak aerobic power) in 16, 24, 28, and 32°C WBGT. In the final 5 min prior to exercise termination, HR was observed to be higher in women relative to men in all but the 32°C WBGT. Although no sex-differences were observed for the HRV metric of root-mean-square of successive differences, high frequency power was higher in women relative to men across WBGT conditions. These findings indicate that, in healthy non-heat-acclimatized individuals, women respond to prolonged exercise-heat stress with a greater increase in HR despite cardiac vagal autonomic modulation remaining equal or increasing compared to men. Novelty points. • Prior to exercise termination, females respond with a greater increase in heart rate under all wet-bulb globe temperatures except the hottest (32°C). • Sex influenced heart rate variability (HRV) metrics during all wet-bulb globe temperatures, but results were mixed. • Further characterisation of HRV sex differences remains an important area of research.
Collapse
Affiliation(s)
| | - Michael J Macartney
- University of Wollongong, 8691, Wollongong, Australia.,University of New South Wales, 7800, Sydney, New South Wales, Australia;
| | - Gregory E Peoples
- University of Wollongong, 8691, School of Medicine, Wollongong, New South Wales, Australia;
| | - Sean R Notley
- University of Ottawa, Faculty of Health Sciences, Ottawa, Ontario, Canada;
| | - Christophe L Herry
- Ottawa Hospital Research Institute, 10055, Clinical Epidemiology, Ottawa, Ontario, Canada;
| | - Glen P Kenny
- University of Ottawa, 6363, Ottawa, Canada, K1N 6N5.,Ottawa Hospital Research Institute, 10055, Ottawa, Canada, K1Y 4E9;
| |
Collapse
|
4
|
Brunet J, Wurz A, Hussien J, Pitman A, Conte E, Ennis JK, Herry CL, Seely AJE, Seely D. Exploring the Effects of Yoga Therapy on Heart Rate Variability and Patient-Reported Outcomes After Cancer Treatment: A Study Protocol. Integr Cancer Ther 2022; 21:15347354221075576. [PMID: 35393867 PMCID: PMC9016564 DOI: 10.1177/15347354221075576] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Following cancer treatment, adults commonly report worsened patient-reported outcomes (PROs) such as anxiety, stress, depression, persistent and upsetting cognitive complaints, unrelenting fatigue, and reduced quality of life. Poorer PROs are associated with disrupted autonomic nervous system functioning as measured by heart rate variability (HRV), both of which have been associated with greater morbidity and mortality. Interventions to improve HRV and PROs among adults following cancer treatment are needed. Yoga therapy holds promise as an intervention to improve HRV and PROs. Therefore, we conducted a single-subject exploratory experimental study to investigate the effects of yoga therapy on HRV and specific PROs (ie, cancer-related fatigue, anxiety, cognitive function, depression, stress, quality of life) in adults treated for cancer. To reduce publication bias, improve reproducibility, and serve as a reference for forthcoming reporting of study results, we present the study protocol for this study herein. METHODS Participants were adults who completed cancer treatment that were recruited from the Ottawa Integrative Cancer Centre. Consenting and eligible participants received one 1:1 yoga therapy session (ie, 1 participant, 1 Yoga Therapist) and 6 weekly group-based yoga therapy sessions (ie, 2-3 participants, 1 Yoga Therapist). Participants completed assessments 7 times: 3 times prior to the program (ie, -6 weeks, -3 weeks, immediately prior to the 1:1 yoga therapy session), immediately following the 1:1 yoga therapy session, prior to the first group-based yoga therapy session, after the last group-based yoga therapy session, and at a 6-week follow-up. Hierarchical linear modeling will be used to test the average effects of the yoga therapy program across participants. DISCUSSION This study will explore several novel hypotheses, including whether yoga therapy can improve HRV and/or specific PROs among adults treated for cancer acutely (ie, during a 1:1 yoga therapy session) and/or through repeated exposure (ie, after completing 6 weeks of group-based yoga therapy). Although the findings will require confirmation or refutation in future trials, they may provide initial evidence that YT may benefit adults treated for cancer. TRIAL REGISTRATION ISRCTN registry, ISRCTN64763228. Registered on December 12, 2021. This trial was registered retrospectively. URL of trial registry record: https://www.isrctn.com/ISRCTN64763228.
Collapse
Affiliation(s)
- Jennifer Brunet
- University of Ottawa, Ottawa, ON, Canada.,Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Institut du savoir de l'Hôpital Montfort, Ottawa, ON, Canada
| | - Amanda Wurz
- University of the Fraser Valley, Chilliwack, BC, Canada
| | | | - Anne Pitman
- The Centre for Health Innovation, Ottawa, ON, Canada
| | - Ellen Conte
- The Centre for Health Innovation, Ottawa, ON, Canada.,Canadian College of Naturopathic Medicine, Toronto, ON, Canada
| | - Julie K Ennis
- The Centre for Health Innovation, Ottawa, ON, Canada
| | | | - Andrew J E Seely
- University of Ottawa, Ottawa, ON, Canada.,The Ottawa Hospital, Ottawa, ON, Canada
| | - Dugald Seely
- University of Ottawa, Ottawa, ON, Canada.,The Centre for Health Innovation, Ottawa, ON, Canada.,Canadian College of Naturopathic Medicine, Toronto, ON, Canada
| |
Collapse
|
5
|
Sarti AJ, Zheng K, Herry CL, Sutherland S, Scales NB, Watpool I, Porteous R, Hickey M, Anstee C, Fazekas A, Ramsay T, Burns KE, Seely AJ. Feasibility of implementing Extubation Advisor, a clinical decision support tool to improve extubation decision-making in the ICU: a mixed-methods observational study. BMJ Open 2021; 11:e045674. [PMID: 34385234 PMCID: PMC8362728 DOI: 10.1136/bmjopen-2020-045674] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
OBJECTIVES Although spontaneous breathing trials (SBTs) are standard of care to extubation readiness, no tool exists that optimises prediction and standardises assessment. In this study, we evaluated the feasibility and clinical impressions of Extubation Advisor (EA), a comprehensive clinical extubation decision support (CDS) tool. DESIGN Phase I mixed-methods observational study. SETTING Two Canadian intensive care units (ICUs). PARTICIPANTS We included patients on mechanical ventilation for ≥24 hours and clinicians (respiratory therapists and intensivists) responsible for extubation decisions. INTERVENTIONS Components included a predictive model assessment, feasibility evaluation, questionnaires and interviews with clinicians. RESULTS We enrolled 117 patients, totalling 151 SBTs and 80 extubations. The incidence of extubation failure was 11% in low-risk patients and 21% in high-risk patients stratified by the predictive model; 38% failed extubation when both the model and clinical impression were at high risk. The tool was well rated: 94% and 75% rated the data entry and EA report as average or better, respectively. Interviews (n=15) revealed favourable impressions regarding its user interface and functionality, but unexpectedly, also concerns regarding EA's potential impact on respiratory therapists' job security. CONCLUSIONS EA implementation was feasible, and users perceived it to have potential to support extubation decision-making. This study helps to understand bedside implementation of CDS tools in a multidisciplinary ICU. TRIAL REGISTRATION NUMBER NCT02988167.
Collapse
Affiliation(s)
- Aimee J Sarti
- Department of Critical Care, Ottawa Hospital, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Katina Zheng
- Medicine, University of Ottawa Faculty of Medicine, Ottawa, Ontario, Canada
| | | | | | | | - Irene Watpool
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | | | - Michael Hickey
- Department of Medicine, Division of Critical Care, University of Toronto, Toronto, Ontario, Canada
| | - Caitlin Anstee
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Anna Fazekas
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Tim Ramsay
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Karen Ea Burns
- St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Andrew Je Seely
- Department of Critical Care, Ottawa Hospital, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Division of Thoracic Surgery, The Ottawa Hospital, Ottawa, Ontario, Canada
- University of Ottawa, Ottawa, Ontario, Canada
| |
Collapse
|
6
|
Herry CL, Soares HMF, Schuler-Faccini L, Frasch MG. Machine learning model on heart rate variability metrics identifies asymptomatic toddlers exposed to zika virus during pregnancy. Physiol Meas 2021; 42. [PMID: 33984844 DOI: 10.1088/1361-6579/ac010e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 12/07/2020] [Accepted: 05/13/2021] [Indexed: 12/27/2022]
Abstract
Objective. Although the Zika virus (ZIKV) seems to be prominently neurotropic, there are some reports of involvement of other organs, particularly the heart. Of special concern are those children exposed prenatally to ZIKV and born without microcephaly or other congenital anomalies. Electrocardiogram (ECG)-derived heart rate variability (HRV) metrics represent an attractive, low-cost, widely deployable tool for early identification of developmental functional alterations in exposed children born without such overt clinical symptoms. We hypothesized that HRV in such children would yield a biomarker of fetal ZIKV exposure. Our objective was to test this hypothesis in young children exposed to ZIKV during pregnancy.Approach. We investigated the HRV properties of 21 children aged 4-25 months from Brazil. The infants were divided into two groups, the ZIKV-exposed (n = 13) and controls (n = 8). Single-channel ECG was recorded in each child at ∼15 months of age and HRV was analyzed in 5 min segments to provide a comprehensive characterization of the degree of variability and complexity of the heart rate.Main results.Using a cubic support vector machine classifier we identified babies as Zika cases or controls with a negative predictive value of 92% and a positive predictive value of 86%. Our results show that a machine learning model derived from HRV metrics can help differentiate between ZIKV-affected, yet asymptomatic, and non-ZIKV-exposed babies. We identified the box count as the best HRV metric in this study allowing such differentiation, regardless of the presence of microcephaly.Significance.We show that it is feasible to measure HRV in infants and toddlers using a small non-invasive portable ECG device and that such an approach may uncover the memory ofin uteroexposure to ZIKV. We discuss putative mechanisms. This approach may be useful for future studies and low-cost screening tools involving this challenging to examine population.
Collapse
Affiliation(s)
| | - Helena M F Soares
- INAGEMP-Departamento de Genética-Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Brazil
| | - Lavinia Schuler-Faccini
- INAGEMP-Departamento de Genética-Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Brazil
| | - Martin G Frasch
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, United States of America
| |
Collapse
|
7
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
8
|
Frasch MG, Walter B, Herry CL, Bauer R. Multimodal pathophysiological dataset of gradual cerebral ischemia in a cohort of juvenile pigs. Sci Data 2021; 8:4. [PMID: 33414507 PMCID: PMC7791136 DOI: 10.1038/s41597-020-00781-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 11/26/2020] [Indexed: 11/09/2022] Open
Abstract
Ischemic brain injuries are frequent and difficult to detect reliably or early. We present the multi-modal data set containing cardiovascular (blood pressure, blood flow, electrocardiogram) and brain electrical activities to derive electroencephalogram (EEG) biomarkers of corticothalamic communication under normal, sedation, and hypoxic/ischemic conditions with ensuing recovery. We provide technical validation using EEGLAB. We also delineate the corresponding changes in the electrocardiogram (ECG)-derived heart rate variability (HRV) with the potential for future in-depth analyses of joint EEG-ECG dynamics. We review an open-source methodology to derive signatures of coupling between the ECoG and electrothalamogram (EThG) signals contained in the presented data set to better characterize the dynamics of thalamocortical communication during these clinically relevant states. The data set is presented in full band sampled at 2000 Hz, so the additional potential exists for insights from the full-band EEG and high-frequency oscillations under the bespoke experimental conditions. Future studies on the dataset may contribute to the development of new brain monitoring technologies, which will facilitate the prevention of neurological injuries. Measurement(s) | EEG with persistent abnormal rhythmic activity • electrocardiogram • Electrothalamogram • cerebral blood flow measurement • positive regulation of heart rate involved in baroreceptor response to decreased systemic arterial blood pressure • cerebral metabolic rate of oxygen • cerebral perfusion pressure | Technology Type(s) | electrophysiology assay • extracellular electrophysiology recording assay • fluorescent colormicrospheres • Electrophysiology | Factor Type(s) | sedation • cerebral ischemia • recovery | Sample Characteristic - Organism | Sus scrofa | Sample Characteristic - Environment | laboratory environment |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.13251176
Collapse
Affiliation(s)
- Martin G Frasch
- University of Washington School of Medicine, Center on Human Development and Disability, Seattle, WA, USA.
| | - Bernd Walter
- Department of Spine Surgery and Neurotraumatology, SRH Waldklinikum, Gera, Germany.,Institute of Molecular Cell Biology, Jena University Hospital, Jena, Germany
| | - Christophe L Herry
- Dynamical Analysis Lab, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Reinhard Bauer
- Institute of Molecular Cell Biology, Jena University Hospital, Jena, Germany.
| |
Collapse
|
9
|
Macartney MJ, Notley SR, Herry CL, Sigal RJ, Boulay P, Kenny GP. Effect of exercise-heat acclimation on cardiac autonomic modulation in type 2 diabetes: a pilot study. Appl Physiol Nutr Metab 2020; 46:284-287. [PMID: 33201735 DOI: 10.1139/apnm-2020-0785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of exercise-heat acclimation on heart rate variability (HRV) in individuals with type 2 diabetes (T2D) remains unclear. We assessed electrocardiogram recordings during exercise-heat stress in middle-aged-to-older individuals (50-70 years) with (n = 6) and without (control; n = 8;) T2D, before and after 7 days of exercise-heat acclimation. Exercising heart rate was reduced (control, -9 ± 5 bpm; T2D, -14 ± 9 bpm) yet HRV was not significantly different. Given the negative correlations between diminished HRV and cardiac risk observed in the scientific literature, further research is warranted. Novelty: Our observations indicate that 7 days exercise-heat acclimation may not effectively attenuate the deviation toward reduced overall HRV and unfavourable cardiac autonomic modulation in individuals with T2D.
Collapse
Affiliation(s)
- Michael J Macartney
- Centre for Medical and Exercise Physiology, Faculty of Science Medicine and Health, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON K1H 8L6, Canada
| | - Ronald J Sigal
- Departments of Medicine, Cardiac Sciences and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON K1H 8L6, Canada
| |
Collapse
|
10
|
Macartney MJ, Meade RD, Notley SR, Herry CL, Seely AJE, Kenny GP. Fluid Loss during Exercise-Heat Stress Reduces Cardiac Vagal Autonomic Modulation. Med Sci Sports Exerc 2020; 52:362-369. [PMID: 31469711 DOI: 10.1249/mss.0000000000002136] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Sweat-induced fluid loss during prolonged exercise-heat stress can compromise cardiovascular and thermoregulatory function, although its effects on cardiac autonomic modulation remain unclear. We therefore examined heart rate variability (HRV) and recovery (HRRec), as surrogates of cardiac autonomic modulation, during and after prolonged exercise in the heat with and without fluid replacement. METHODS Eleven young and healthy men performed 90 min of semi-recumbent cycling in dry heat (40°C; 20% relative humidity) at a fixed rate of metabolic heat production (600 W; ~46% V˙O2peak) followed by 40-min resting recovery without fluid replacement (No-FR; ~3.4% reduction in body mass). On a separate day, participants completed the same protocol with fluid replacement (FR; 500-700 mL timed boluses) to offset sweat losses. Esophageal temperature and ECG were recorded throughout, with measurements analyzed over 10-min averaged epochs during baseline, each 30-min interval during exercise and 20-min interval during recovery. RESULTS Esophageal temperature and heart rate were elevated in No-FR relative to FR throughout exercise (all P ≤ 0.02). The HRV indices reflecting vagal influence of heart rate including the cardiac vagal index (CVI = log10[16 × SD1 × SD2]) and root-mean-square of successive differences were attenuated throughout exercise relative to baseline in both conditions (all P < 0.05), with the magnitude of the reduction greater in the No-FR condition (all P < 0.05). Further, sample entropy was reduced throughout all time points measured during exercise in the No-FR relative to FR condition (all P ≤ 0.03). CONCLUSIONS Our unique observations indicate that while prolonged exercise heat stress attenuates the vagal influence and complexity of cardiac rhythms, that reduction is further exacerbated by fluid loss, highlighting the importance of fluid replacement in such conditions.
Collapse
Affiliation(s)
- Michael J Macartney
- School of Health Sciences, College of Health and Medicine, University of Tasmania, Hobart, AUSTRALIA
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, CANADA
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, CANADA
| | - Christophe L Herry
- Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, CANADA
| | | | | |
Collapse
|
11
|
Kaltsatou A, Flouris AD, Herry CL, Notley SR, Macartney MJ, Seely AJE, Kenny GP. Heart rate variability in older workers during work under the Threshold Limit Values for heat exposure. Am J Ind Med 2020; 63:787-795. [PMID: 32677129 DOI: 10.1002/ajim.23156] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 11/11/2022]
Abstract
BACKGROUND The Threshold Limit Values (TLV) of the American Conference of Governmental and Industrial Hygienists indicate the levels of heat stress that all workers may be repeatedly exposed to without adverse health effects. In this study, we evaluated heart rate variability (HRV) during moderate-to-heavy work performed continuously or according to different TLV work-rest (WR) allocations in healthy physically active older workers. METHODS Nine healthy older (58 ± 5 years) males performed three different 120-minute conditions in accordance with TLV guidelines for moderate-to-heavy intensity work (360 W fixed rate of heat production) in different wet-bulb globe temperatures (WBGT): continuous cycling at 28°C WBGT (CON), as well as intermitted work performed at WR of 3:1 in 29°C WBGT (WR3:1), and at WR of 1:1 at 30°C (WR1:1). Rectal temperature and HRV (3-lead electrocardiogram [ECG]) were assessed throughout. RESULTS Coefficient of Variation, Poincaré SD2, and Shannon Entropy were decreased during the CON compared with the WR3:1 when core temperature exceeded 38°C and after 1 hour of continuous work (P < .05). Also, 4 of the 12 HRV indices studied were reduced at CON compared with WR1:1 after 2 hours of accumulated work time (P < .05). Participants worked longer before core temperature reached 38°C during the WR1:1 and the WR3:1, compared with CON (P < .05). CONCLUSIONS Incorporating breaks during moderate-to-heavy work in the heat for older adults can reduce autonomic stress and prolong the work performed at safe core temperature levels. The TLV WR1:1 provides increased cardiac protection for older workers, as compared with the CON and the WR3:1.
Collapse
Affiliation(s)
- Antonia Kaltsatou
- FAME Laboratory, Department of Exercise ScienceUniversity of ThessalyTrikala Greece
| | - Andreas D. Flouris
- FAME Laboratory, Department of Exercise ScienceUniversity of ThessalyTrikala Greece
- Human and Environmental Physiology Research Unit, School of Human KineticsUniversity of Ottawa Canada
| | - Christophe L. Herry
- Division of Thoracic Surgery and Critical Care MedicineOttawa HospitalOttawa Ontario Canada
| | - Sean R. Notley
- Human and Environmental Physiology Research Unit, School of Human KineticsUniversity of Ottawa Canada
| | - Michael J. Macartney
- School of Health Sciences, College of Health and MedicineUniversity of TasmaniaHobart Tasmania Australia
| | - Andrew J. E. Seely
- Division of Thoracic Surgery and Critical Care MedicineOttawa HospitalOttawa Ontario Canada
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, School of Human KineticsUniversity of Ottawa Canada
- Clinical Epidemiology ProgramOttawa Hospital Research InstituteOttawa Ontario Canada
| |
Collapse
|
12
|
Macartney MJ, Notley SR, Meade RD, Herry CL, Kenny GP. Heart rate variability in older men on the day following prolonged work in the heat. J Occup Environ Hyg 2020; 17:383-389. [PMID: 32649261 DOI: 10.1080/15459624.2020.1779932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Susceptibility to heat illness during physically demanding work in hot environments is greater on the second of two consecutive workdays. While it has been demonstrated that heat storage is exacerbated on the second compared to first workday in older workers (50-65 yr), the effects on heart rate variability (HRV), an established surrogate of cardiac autonomic modulation, remain unclear. This study evaluated HRV in older workers on the day following prolonged work in the heat. Electrocardiogram was recorded in nine older (53-64 yr) males at rest, during three 30-min bouts of semi-recumbent cycling at fixed rates of metabolic heat production (150, 200, 250 W/m2), each separated by 15-min recovery. Experiments were conducted in hot-dry conditions (40 °C, 20% relative humidity), immediately prior to (Day 1), and on the day following (Day 2), a prolonged work simulation (∼7.5 hr) involving moderate intensity intermittent exercise in hot-dry conditions (38 °C, 34% relative humidity). Core temperature, as well as time, frequency, and nonlinear HRV indices were derived for analysis during rest, the final 5-min of exercise at the highest heat production and recovery. The change in core temperature at the end of work (mean ±SD) was significantly greater on Day 2 (1.0 °C ±0.3) relative to Day 1 (0.8 °C ±0.2; p < 0.01). Heart rate, however, did not significantly differ between days 1 and 2 at rest (Day 1, 59 ±11 bpm; Day 2, 62 ±13 bpm), during exercise (Day 1, 113 ±21 bpm; Day 2, 114 ±18 bpm ) and at the end of recovery (Day 1, 75 ±16 bpm; Day 2, 76 ±12 bpm). Likewise, there were no significant differences in any HRV indices derived from time, frequency, and nonlinear domains (all p > 0.05). Prolonged work in the heat did not modulate next-day heart rhythms, as reflected by HRV, despite augmented core temperature. While HRV can reflect physiological aspects of cardiac autonomic stressors, these findings indicate it does not provide a means to identify exacerbated heat strain in older workers over consecutive work shifts in the heat.
Collapse
Affiliation(s)
| | - Sean R Notley
- School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Robert D Meade
- School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottowa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Glen P Kenny
- School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| |
Collapse
|
13
|
Macartney MJ, Notley SR, Herry CL, Seely AJE, Sigal RJ, Kenny GP. Cardiac autonomic modulation in type 1 diabetes during exercise-heat stress. Acta Diabetol 2020; 57:959-963. [PMID: 32144491 DOI: 10.1007/s00592-020-01505-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 02/14/2020] [Indexed: 12/30/2022]
Abstract
AIMS Cardiac autonomic modulation, as assessed by heart rate variability (HRV), is independently attenuated by both type 1 diabetes (T1D) and exercise-heat stress, although their combined effects remain unclear. We therefore assessed HRV during exercise-heat stress in young individuals (18-37 years) with (n = 14) and without type 1 diabetes (n = 14). METHODS Participants completed 30-min seated rest and three, 30-min bouts of semi-recumbent cycling at light, moderate, and vigorous metabolic heat productions (200, 250, 300 W/m2, respectively), each followed by 30-min recovery. Body core temperature (Tcore) and electrocardiogram were recorded throughout and analyzed during the final 5-min of rest and each exercise period. RESULTS Relative to baseline, Tcore was increased in both groups, albeit to a greater extent in type 1 diabetes during vigorous exercise (T1D, 1.1 ± 0.3 °C; control, 0.8 ± 0.3 °C; P < 0.05). Overall HRV (as reflected by entropy) was attenuated throughout exercise relative to baseline in both groups, with the magnitude of the reduction greater in type 1 diabetes during vigorous exercise (T1D, - 108%; control, - 70%; P < 0.05). CONCLUSIONS Given the negative correlations between decreased HRV and cardiac risk, our novel observations indicate that vigorous exercise in hot environments may pose a health concern for individuals with type 1 diabetes.
Collapse
Affiliation(s)
- Michael J Macartney
- School of Health Sciences, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Andrew J E Seely
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
- Thoracic Surgery and Critical Care Medicine, The Ottawa Hospital, Ottawa, Canada
- Department of Medicine, University of Ottawa, Ottawa, Canada
| | - Ronald J Sigal
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
- Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
- Departments of Medicine, Cardiac Sciences and Community Health Sciences, Cumming School of Medicine, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada.
- Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada.
| |
Collapse
|
14
|
Macartney MJ, Notley SR, Herry CL, Seely AJE, Sigal RJ, Kenny GP. Diminished heart rate variability in type 2 diabetes is exacerbated during exercise-heat stress. Acta Diabetol 2020; 57:899-901. [PMID: 32008160 DOI: 10.1007/s00592-020-01482-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/11/2020] [Indexed: 11/29/2022]
Affiliation(s)
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Andrew J E Seely
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Thoracic Surgery and Critical Care Medicine, The Ottawa Hospital, Ottawa, Canada
| | - Ronald J Sigal
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Departments of Medicine, Cardiac Sciences and Community Health Sciences, Cumming School of Medicine, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada.
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
| |
Collapse
|
15
|
Kaltsatou A, Flouris AD, Herry CL, Notley SR, Seely AJE, Beatty HW, Kenny GP. Age differences in cardiac autonomic regulation during intermittent exercise in the heat. Eur J Appl Physiol 2020; 120:453-465. [PMID: 31894413 DOI: 10.1007/s00421-019-04290-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 12/18/2019] [Indexed: 12/19/2022]
Abstract
PURPOSE This study aimed to detect potential differences in heart-rate variability (HRV) during a moderate-intensity intermittent exercise in the heat among physically active young (25.8 ± 1.9 years), middle-aged (43.5 ± 2.8 years), and older (62.9 ± 3.7 years) men. METHODS Thirty-three participants (11/group) performed four successive bouts of 15-min cycling at a moderate fixed rate of metabolic heat production of ~ 400 W; each separated by a 15-min recovery with 1 h of final recovery in a hot and dry environment (35 °C, 20% relative humidity). Twelve HRV indices were computed that have been commonly described in the literature, and characterized various domains of the variability and complexity of heart rate. RESULTS Cardiac autonomic regulation during intermittent exercise in the heat, as well as during pre-exercise rest and recovery was significantly affected by age, as changes were observed among the three different aged groups in five indices (p ≤ 0.05). Similarly, time influenced cardiac autonomic regulation as three indices showed changes across time (p ≤ 0.05) during intermittent exercise, whilst five indices displayed significant changes (p ≤ 0.05) during rest and recovery in the heat. CONCLUSIONS This study supports that moderate-intensity intermittent exercise in the heat is associated with significant cardiac autonomic dysregulation in older men, as compared to young and middle-aged men, yet it highlights the importance of developing preventative health strategies for heat-related illness in aged individuals.
Collapse
Affiliation(s)
- Antonia Kaltsatou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100, Trikala, Greece
| | - Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100, Trikala, Greece
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University Private, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Christophe L Herry
- Clinical Epidemiological Program of the Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University Private, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Andrew J E Seely
- Clinical Epidemiological Program of the Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Thoracic Surgery and Critical Care Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Heather Wright Beatty
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University Private, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University Private, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada.
- Clinical Epidemiological Program of the Ottawa Hospital Research Institute, Ottawa, ON, Canada.
| |
Collapse
|
16
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
17
|
Carrillo AE, Flouris AD, Herry CL, Notley SR, Macartney MJ, Seely AJE, Wright Beatty HE, Kenny GP. Age-related reductions in heart rate variability do not worsen during exposure to humid compared to dry heat: A secondary analysis. Temperature (Austin) 2019; 6:341-345. [PMID: 31934605 DOI: 10.1080/23328940.2019.1684791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 10/03/2019] [Revised: 10/21/2019] [Accepted: 10/21/2019] [Indexed: 10/25/2022] Open
Abstract
We conducted a secondary analysis to investigate whether age-related attenuations in heart rate variability (HRV) worsen during exposure to moderate, dry (36.5°C, 20% RH) or humid (36.5°C, 60% RH) heat conditions that resulted in greater body heat storage among older compared to young participants, and during humid compared to dry heat, regardless of age. Six HRV indices [heart rate (HR), coefficient of variation (CoV), detrended fluctuation analysis: α1, low frequency power, high frequency power, and low/high frequency ratio] were assessed in 10 young (21 ± 3 y) and 9 older (65 ± 5 y) adults for 15-min prior to (baseline), and at the end of a 120-min exposure to dry and humid heat while seated at rest. Our results demonstrated a condition (dry and humid) x time (baseline and end) interaction effect on HR (p = 0.047) such that HR gradually increased during humid heat exposure yet remained similar during dry heat exposure across groups. We also found an age-related attenuation in CoV at baseline for both the dry (young: 0.097 ± 0.023%; older: 0.054 ± 0.016%) and humid (young: 0.093 ± 0.034%; older: 0.056 ± 0.014%) heat conditions (p < 0.02). Those age-related attenuations in CoV, however, were not magnified throughout the exposure nor different between conditions (p > 0.05). While older adults stored more heat during a brief 120-min exposure to dry heat compared to their young counterparts, this was not paralleled by further age-related impairments in HRV even when body heat storage and cardiovascular strain were exacerbated by exposure to humid heat.
Collapse
Affiliation(s)
- Andres E Carrillo
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece.,Department of Movement Science, Chatham University, Pittsburgh, PA, USA
| | - Andreas D Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece.,Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Michael J Macartney
- School of Health Sciences, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Andrew J E Seely
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Thoracic Surgery and Critical Care Medicine, The Ottawa Hospital, Ottawa, ON, Canada
| | - Heather E Wright Beatty
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| |
Collapse
|
18
|
Herry CL, Schüler-Faccini L, Silva HM, Barbosa CP, Ecco G, Frasch MG. #29 Heart rate variability monitoring identifies asymptomatic toddlers exposed to Zika virus during pregnancy. Reprod Toxicol 2019. [DOI: 10.1016/j.reprotox.2019.05.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
19
|
Herry CL, Burns P, Desrochers A, Fecteau G, Durosier LD, Cao M, Seely AJE, Frasch MG. Vagal contributions to fetal heart rate variability: an omics approach. Physiol Meas 2019; 40:065004. [PMID: 31091517 DOI: 10.1088/1361-6579/ab21ae] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Fetal heart rate variability (fHRV) is an important indicator of health and disease, yet its physiological origins, neural contributions, in particular, are not well understood. We aimed to develop novel experimental and data analytical approaches to identify fHRV measures reflecting the vagus nerve contributions to fHRV. APPROACH In near-term ovine fetuses, a comprehensive set of 46 fHRV measures was computed from fetal pre-cordial electrocardiogram recorded during surgery and 72 h later without (n = 24) and with intra-surgical bilateral cervical vagotomy (n = 15). MAIN RESULTS The fetal heart rate did not change due to vagotomy. We identify fHRV measures specific to the vagal modulation of fHRV: multiscale time irreversibility asymmetry index (AsymI), detrended fluctuation analysis (DFA) α 1, Kullback-Leibler permutation entropy (KLPE) and scale-dependent Lyapunov exponent slope (SDLE α). SIGNIFICANCE We provide a systematic delineation of vagal contributions to fHRV across signal-analytical domains which should be relevant for the emerging field of bioelectronic medicine and the deciphering of the 'vagus code'. Our findings also have clinical significance for in utero monitoring of fetal health during surgery. Key points •Fetal surgery causes a complex pattern of changes in heart rate variability measures with an overall reduction of complexity or variability. •At 72 h after surgery, many of the HRV measures recover and this recovery is delayed by an intrasurgical cervical bilateral vagotomy. •We identify HRV pattern representing complete vagal withdrawal that can be understood as part of 'HRV code', rather than any single HRV measure. •We identify HRV biomarkers of recovery from fetal surgery and discuss the effect of anticholinergic medication on this recovery.
Collapse
Affiliation(s)
- Christophe L Herry
- Ottawa Hospital Research Institute, University of Ottawa, ON, Canada. PB and CH contributed equally to this manuscript
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Flouris AD, Friesen BJ, Herry CL, Seely AJE, Notley SR, Kenny GP. Heart rate variability dynamics during treatment for exertional heat strain when immediate response is not possible. Exp Physiol 2019; 104:845-854. [PMID: 30932277 DOI: 10.1113/ep087297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 08/15/2018] [Accepted: 03/25/2019] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a delay in cold water immersion treatment affect the cardiac autonomic control of exertionally heat-strained individuals? What is the main finding and its importance? Cold water immersion is effective for treating exertionally heat-strained individuals even when treatment is commenced with a significant delay. However, that treatment delay leads to only partial/transient restoration of cardiac autonomic control. Therefore, we recommend that exertional heatstroke patients are continuously monitored for several hours even after core temperature has returned to normal values. ABSTRACT Immediate cold water immersion (CWI) is the gold-standard treatment for exertional heatstroke. In the field, however, treatment is often delayed, primarily owing to a delayed paramedic response and/or inaccurate diagnosis. We examined the effect of treatment (reduction of rectal temperature to 37.5°C) delays of 5 (short), 20 (moderate) and 40 (prolonged) min on cardiac autonomic control [as assessed via heart rate variability (HRV)] in eight exertionally heat-strained (40.0°C rectal temperature) individuals. Eleven HRV indices were computed that have been described commonly in the literature and characterize almost all known domains of the variability and complexity of the cardiopulmonary system. We found that the cardiac autonomic control (as assessed via HRV) of exertionally heat-strained individuals was significantly affected by the amount of time it took for the CWI treatment to be applied. Six out of 11 HRV indices studied, from all variability domains, displayed strong (P ≤ 0.005) time × delay interaction effects. Moreover, the number of significantly (P ≤ 0.005) abnormal (i.e. different from the short delay) HRV indices more than doubled (seven versus 15) from the moderate delay to the prolonged delay. Finally, our results demonstrated that a CWI treatment applied with delays of 20 and, primarily, 40 min did not lead to a full restoration of cardiac autonomic control of exertionally heat-strained individuals. In conclusion, this study supports CWI for treating exertionally heat-strained individuals even when applied with prolonged delay, but it highlights the importance of continued cardiac monitoring of patients who have suffered exertional heatstroke for several hours after restoration of core temperature to normal.
Collapse
Affiliation(s)
- Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, 42100, Greece.,Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Brian J Friesen
- Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ontario, Canada
| | - Andrew J E Seely
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ontario, Canada.,Thoracic Surgery and Critical Care Medicine, Ottawa Hospital, Ontario, Canada
| | - Sean R Notley
- Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Glen P Kenny
- Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ontario, Canada
| |
Collapse
|
21
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
22
|
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] [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 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.
Collapse
Affiliation(s)
- C Shen
- Mathematics, Duke University, Durham NC, United States of America
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Leicht AS, Flouris AD, Kaltsatou A, Seely AJ, Herry CL, Wright Beatty HE, Kenny GP. Age alters cardiac autonomic modulations during and following exercise-induced heat stress in females. Temperature (Austin) 2018; 5:184-196. [PMID: 30377635 DOI: 10.1080/23328940.2018.1432918] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 09/05/2017] [Revised: 01/26/2018] [Accepted: 02/07/2018] [Indexed: 12/19/2022] Open
Abstract
The aim of this study was to examine the effect of natural ageing on heart rate variability during and following exercise-induced heat stress in females. Eleven young (∼24 years) and 13 older (∼51 years), habitually active females completed an experimental session consisting of baseline rest, moderate intensity intermittent exercise (four 15-min bouts separated by 15-min recovery) and 1-hour of final recovery in a hot and dry (35°C, 20% relative humidity) environment. Respiratory and heart rate recordings were continuously logged with 10-min periods analysed at the end of: baseline rest; each of the exercise and recovery bouts; and during the 1-hour final recovery period. Comparisons over time during exercise and recovery, and between groups were conducted via two-way repeated-measures ANCOVAs with rest values as the covariate. During baseline rest, older females exhibited lower heart rate variability compared to young females with similar levels of respiration and most (∼71-79%) heart rate variability measures during repeated exercise and recovery. However, older females exhibited heart rate variability metrics suggestive of greater parasympathetic modulation (greater long axis of Poincare plot, cardiac vagal index; lower low-high frequency ratio) during repeated exercise with lower indices during the latter stage of prolonged recovery (less very low frequency component, Largest Lyapunov Exponent; greater cardiac sympathetic index). The current study documented several unique, age-dependent differences in heart rate variability, independent of respiration, during and following exercise-induced heat stress for females that may assist in the detection of normal heat-induced adaptations as well as individuals vulnerable to heat stress.
Collapse
Affiliation(s)
- Anthony S Leicht
- Sport and Exercise Science, James Cook University, Townsville, Australia
| | - Andreas D Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Antonia Kaltsatou
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Andrew J Seely
- Divisions of Thoracic Surgery and Critical Care Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Christophe L Herry
- Dynamical Analysis Lab, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ontario, Canada
| | | | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ontario, Canada
| |
Collapse
|
24
|
Gold N, Frasch MG, Herry CL, Richardson BS, Wang X. A Doubly Stochastic Change Point Detection Algorithm for Noisy Biological Signals. Front Physiol 2018; 8:1112. [PMID: 29379444 PMCID: PMC5760503 DOI: 10.3389/fphys.2017.01112] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 12/15/2017] [Indexed: 11/13/2022] Open
Abstract
Experimentally and clinically collected time series data are often contaminated with significant confounding noise, creating short, noisy time series. This noise, due to natural variability and measurement error, poses a challenge to conventional change point detection methods. We propose a novel and robust statistical method for change point detection for noisy biological time sequences. Our method is a significant improvement over traditional change point detection methods, which only examine a potential anomaly at a single time point. In contrast, our method considers all suspected anomaly points and considers the joint probability distribution of the number of change points and the elapsed time between two consecutive anomalies. We validate our method with three simulated time series, a widely accepted benchmark data set, two geological time series, a data set of ECG recordings, and a physiological data set of heart rate variability measurements of fetal sheep model of human labor, comparing it to three existing methods. Our method demonstrates significantly improved performance over the existing point-wise detection methods.
Collapse
Affiliation(s)
- Nathan Gold
- Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Martin G. Frasch
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, United States
| | - Christophe L. Herry
- Dynamical Analysis Laboratory, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Bryan S. Richardson
- Department of Obstetrics and Gynecology, London Health Sciences Centre, Victoria Hospital, London, ON, Canada
| | - Xiaogang Wang
- Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| |
Collapse
|
25
|
Barnaby DP, Fernando SM, Ferrick KJ, Herry CL, Seely AJE, Bijur PE, Gallagher EJ. Use of the low-frequency/high-frequency ratio of heart rate variability to predict short-term deterioration in emergency department patients with sepsis. Emerg Med J 2017; 35:96-102. [PMID: 28821492 DOI: 10.1136/emermed-2017-206625] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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: 01/23/2017] [Revised: 07/26/2017] [Accepted: 07/30/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To examine the ability of the low-frequency/high-frequency (LF/HF) ratio of heart rate variability (HRV) analysis to identify patients with sepsis at risk of early deterioration. METHODS This is a prospective observational cohort study of patients with sepsis presenting to the Montefiore Medical Center ED from December 2014 through September 2015. On presentation, a single ECG Holter recording was obtained and analysed to obtain the LF/HF ratio of HRV. Initial Sequential Organ Failure Assessment (SOFA) scores were computed. Patients were followed for 72 hours to identify those with early deterioration. RESULTS 466 patients presenting to the ED with sepsis were analysed. Thirty-two (7%) reached at least one endpoint within 72 hours. An LF/HF ratio <1 had a sensitivity and specificity of 34% (95% CI (19% to 53%)) and 82% (95% CI (78% to 85%)), respectively, with positive and negative likelihood ratios of 1.9 (95% CI (1.1 to 3.2)) and 0.8 (95% CI (0.6 to 1.0)). An initial SOFA score ≥3 had a sensitivity and specificity of 38% (95% CI (22% to 56%)) and 92% (95% CI (89% to 95%)), with positive and negative likelihood ratios of 4.9 (95% CI (2.8 to 8.6)) and 0.7 (95% CI (0.5 to 0.9)). The composite measure of HRV+SOFA had improved sensitivity (56%, 95% CI (38% to 73%)) but at the expense of specificity (77%, 95% CI (72% to 80%)), with positive and negative likelihood ratios of 2.4 (95% CI (1.7 to 3.4)) and 0.6 (95% CI (0.4 to 0.9)). Receiver operating characteristic analysis did not identify a superior alternate threshold for the LF/HF ratio. Kaplan-Meier survival functions differed significantly (p=0.02) between low (<1) and high (≥1) LF/HF groups. CONCLUSIONS While we found a statistically significant relationship between HRV, SOFA and HRV+SOFA, and early deterioration, none reliably functioned as a clinical predictive tool. More complex multivariable models will likely be required to construct models with clinical utility.
Collapse
Affiliation(s)
- Douglas P Barnaby
- Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Shannon M Fernando
- Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Kevin J Ferrick
- Department of Medicine, Division of Cardiology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Andrew J E Seely
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Departments of Surgery and Critical Care Medicine, University of Ottawa Faculty of Medicine, Ottawa, Ontario, Canada
| | - Polly E Bijur
- Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - E John Gallagher
- Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| |
Collapse
|
26
|
Herry CL, Frasch M, Seely AJE, Wu HT. Heart beat classification from single-lead ECG using the synchrosqueezing transform. Physiol Meas 2017; 38:171-187. [DOI: 10.1088/1361-6579/aa5070] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
27
|
Carrillo AE, Flouris AD, Herry CL, Poirier MP, Boulay P, Dervis S, Friesen BJ, Malcolm J, Sigal RJ, Seely AJE, Kenny GP. Heart rate variability during high heat stress: a comparison between young and older adults with and without Type 2 diabetes. Am J Physiol Regul Integr Comp Physiol 2016; 311:R669-R675. [PMID: 27511279 DOI: 10.1152/ajpregu.00176.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [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: 05/02/2016] [Accepted: 08/08/2016] [Indexed: 11/22/2022]
Abstract
We examined whether older individuals with and without Type 2 diabetes (T2D) experience differences in heart rate variability (HRV) during a 3-h exposure to high heat stress compared with young adults. Young (Young; n = 22; 23 ± 3 yr) and older individuals with (T2D; n = 11; 59 ± 9 yr) and without (Older; n = 25; 63 ± 5 yr) T2D were exposed to heat stress (44°C, 30% relative humidity) for 3 h. Fifty-five HRV measures were assessed for 15 min at baseline and at minutes 82.5-97.5 (Mid) and minutes 165-180 (End) during heat stress. When compared with Young, a similar number of HRV indices were significantly different (P < 0.05) in Older (Baseline: 35; Mid: 29; End: 32) and T2D (Baseline: 31; Mid: 30; End: 27). In contrast, the number of HRV indices significantly different (P < 0.05) between Older and T2D were far fewer (Baseline: 13, Mid: 1, End: 3). Within-group analyses demonstrated a greater change in the Young group's HRV during heat stress compared with Older and T2D; the number of significantly different (P < 0.05) HRV indices between baseline and End were 42, 29, and 20, for Young, Older, and T2D, respectively. Analysis of specific HRV domains suggest that the Young group experienced greater sympathetic activity during heat stress compared with Older and T2D. In conclusion, when compared with young, older individuals with and without T2D demonstrate low HRV at baseline and less change in HRV (including an attenuated sympathetic response) during 3 h high heat stress, potentially contributing to impaired thermoregulatory function.
Collapse
Affiliation(s)
- Andres E Carrillo
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece.,Department of Exercise Science, Chatham University, Pittsburgh, Pennsylvania
| | - Andreas D Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece.,Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Martin P Poirier
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Sheila Dervis
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Brian J Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Janine Malcolm
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Ronald J Sigal
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Departments of Medicine, Cardiac Sciences, and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Alberta, Canada; and
| | - Andrew J E Seely
- Thoracic Surgery and Critical Care Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; .,Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| |
Collapse
|
28
|
Durosier LD, Herry CL, Cortes M, Cao M, Burns P, Desrochers A, Fecteau G, Seely AJE, Frasch MG. Does heart rate variability reflect the systemic inflammatory response in a fetal sheep model of lipopolysaccharide-induced sepsis? Physiol Meas 2015; 36:2089-102. [PMID: 26290042 DOI: 10.1088/0967-3334/36/10/2089] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fetal inflammatory response occurs during chorioamnionitis, a frequent and often subclinical inflammation associated with increased risk for brain injury and life-lasting neurologic deficits. No means of early detection exist. We hypothesized that systemic fetal inflammation without septic shock will be reflected in alterations of fetal heart rate (FHR) variability (fHRV) distinguishing baseline versus inflammatory response states. In chronically instrumented near-term fetal sheep (n = 24), we induced an inflammatory response with lipopolysaccharide (LPS) injected intravenously (n = 14). Ten additional fetuses served as controls. We measured fetal plasma inflammatory cytokine IL-6 at baseline, 1, 3, 6, 24 and 48 h. 44 fHRV measures were determined continuously every 5 min using continuous individualized multi-organ variability analysis (CIMVA). CIMVA creates an fHRV measures matrix across five signal-analytical domains, thus describing complementary properties of fHRV. Using principal component analysis (PCA), a widely used technique for dimensionality reduction, we derived and quantitatively compared the CIMVA fHRV PCA signatures of inflammatory response in LPS and control groups. In the LPS group, IL-6 peaked at 3 h. In parallel, PCA-derived fHRV composite measures revealed a significant difference between LPS and control group at different time points. For the LPS group, a sharp increase compared to baseline levels was observed between 3 h and 6 h, and then abating to baseline levels, thus tracking closely the IL-6 inflammatory profile. This pattern was not observed in the control group. We also show that a preselection of fHRV measures prior to the PCA can potentially increase the difference between LPS and control groups, as early as 1 h post LPS injection. We propose a fHRV composite measure that correlates well with levels of inflammation and tracks well its temporal profile. Our results highlight the potential role of HRV to study and monitor the inflammatory response non-invasively over time.
Collapse
Affiliation(s)
- Lucien D Durosier
- Dept. of OBGYN and Dept. of Neurosciences, CHU Ste-Justine Research Centre, l'Université de Montréal, Montréal, QC, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Herry CL, Townsend D, Green GC, Bravi A, Seely AJE. Segmentation and classification of capnograms: application in respiratory variability analysis. Physiol Meas 2014; 35:2343-58. [PMID: 25389703 DOI: 10.1088/0967-3334/35/12/2343] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [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
Variability analysis of respiratory waveforms has been shown to provide key insights into respiratory physiology and has been used successfully to predict clinical outcomes. The current standard for quality assessment of the capnogram signal relies on a visual analysis performed by an expert in order to identify waveform artifacts. Automated processing of capnograms is desirable in order to extract clinically useful features over extended periods of time in a patient monitoring environment. However, the proper interpretation of capnogram derived features depends upon the quality of the underlying waveform. In addition, the comparison of capnogram datasets across studies requires a more practical approach than a visual analysis and selection of high-quality breath data. This paper describes a system that automatically extracts breath-by-breath features from capnograms and estimates the quality of individual breaths derived from them. Segmented capnogram breaths were presented to expert annotators, who labeled the individual physiological breaths into normal and multiple abnormal breath types. All abnormal breath types were aggregated into the abnormal class for the purpose of this manuscript, with respiratory variability analysis as the end-application. A database of 11,526 breaths from over 300 patients was created, comprising around 35% abnormal breaths. Several simple classifiers were trained through a stratified repeated ten-fold cross-validation and tested on an unseen portion of the labeled breath database, using a subset of 15 features derived from each breath curve. Decision Tree, K-Nearest Neighbors (KNN) and Naive Bayes classifiers were close in terms of performance (AUC of 90%, 89% and 88% respectively), while using 7, 4 and 5 breath features, respectively. When compared to airflow derived timings, the 95% confidence interval on the mean difference in interbreath intervals was ± 0.18 s. This breath classification system provides a fast and robust pre-processing of continuous respiratory waveforms, thereby ensuring reliable variability analysis of breath-by-breath parameter time series.
Collapse
Affiliation(s)
- C L Herry
- Ottawa Hospital Research Institute, Ottawa Hospital-General Campus, 501 Smyth Road-Box 708, Ottawa ON K1H 8L6, Canada
| | | | | | | | | |
Collapse
|
30
|
Abstract
Neural synchronization is a key mechanism to a wide variety of brain functions, such as cognition, perception, or memory. High temporal resolution achieved by EEG recordings allows the study of the dynamical properties of synchronous patterns of activity at a very fine temporal scale but with very low spatial resolution. Spatial resolution can be improved by retrieving the neural sources of EEG signal, thus solving the so-called inverse problem. Although many methods have been proposed to solve the inverse problem and localize brain activity, few of them target the synchronous brain regions. In this paper, we propose a novel algorithm aimed at localizing specifically synchronous brain regions and reconstructing the time course of their activity. Using multivariate wavelet ridge analysis, we extract signals capturing the synchronous events buried in the EEG and then solve the inverse problem on these signals. Using simulated data, we compare results of source reconstruction accuracy achieved by our method to a standard source reconstruction approach. We show that the proposed method performs better across a wide range of noise levels and source configurations. In addition, we applied our method on real dataset and identified successfully cortical areas involved in the functional network underlying visual face perception. We conclude that the proposed approach allows an accurate localization of synchronous brain regions and a robust estimation of their activity.
Collapse
Affiliation(s)
- Younes Zerouali
- Ecole de Technologie Supérieure, Université du Québec, Montreal, QC, Canada.
| | | | | | | |
Collapse
|
31
|
Herry CL, Frize M, Goubran RA. Segmentation and landmark identification in infrared images of the human body. Conf Proc IEEE Eng Med Biol Soc 2008; 2006:957-60. [PMID: 17946429 DOI: 10.1109/iembs.2006.260077] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The segmentation and landmark identification in infrared images of the human body are key steps in a computerized processing of large database of thermal images. The segmentation task is especially challenging due to specific characteristics of thermal images. Few papers deal with segmentation techniques for clinical infrared images and available segmentation methods (e.g. for breast or military thermal images) do not perform well on other types of images. This paper presents a few strategies for the automated segmentation and registration of anatomical landmarks on thermal images of arms and hands. The segmentation method is based on mathematical morphological operations and simple rule based processing easily available through prior knowledge about the objects of interest.
Collapse
Affiliation(s)
- C L Herry
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada.
| | | | | |
Collapse
|
32
|
Herry CL, Frize M, Goubran RA, Comeau G. Evolution of the surface temperature of pianists' arm muscles using infrared thermography. Conf Proc IEEE Eng Med Biol Soc 2007; 2005:1687-90. [PMID: 17282537 DOI: 10.1109/iembs.2005.1616768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Musculoskeletal disorders are very frequent among musicians. Diagnosis is difficult due to the lack of objective tests and the multiplicity of symptoms. Treatment is also problematic and often requires that the musician stop playing. Most of these disorders are inflammatory in nature, and therefore involve temperature changes in the affected regions. Temperature measurements were recorded with an infrared camera. In this paper we present an overview of the temperature measurements made in the arms of 8 pianists during regular piano practice sessions.
Collapse
Affiliation(s)
- C L Herry
- Department of Systems and Computer Engineering, Carleton University, Ottawa, ON Canada
| | | | | | | |
Collapse
|
33
|
Herry CL, Frize M. Quantitative assessment of pain-related thermal dysfunction through clinical digital infrared thermal imaging. Biomed Eng Online 2004; 3:19. [PMID: 15222887 PMCID: PMC455685 DOI: 10.1186/1475-925x-3-19] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2004] [Accepted: 06/28/2004] [Indexed: 11/17/2022] Open
Abstract
Background The skin temperature distribution of a healthy human body exhibits a contralateral symmetry. Some nociceptive and most neuropathic pain pathologies are associated with an alteration of the thermal distribution of the human body. Since the dissipation of heat through the skin occurs for the most part in the form of infrared radiation, infrared thermography is the method of choice to study the physiology of thermoregulation and the thermal dysfunction associated with pain. Assessing thermograms is a complex and subjective task that can be greatly facilitated by computerised techniques. Methods This paper presents techniques for automated computerised assessment of thermal images of pain, in order to facilitate the physician's decision making. First, the thermal images are pre-processed to reduce the noise introduced during the initial acquisition and to extract the irrelevant background. Then, potential regions of interest are identified using fixed dermatomal subdivisions of the body, isothermal analysis and segmentation techniques. Finally, we assess the degree of asymmetry between contralateral regions of interest using statistical computations and distance measures between comparable regions. Results The wavelet domain-based Poisson noise removal techniques compared favourably against Wiener and other wavelet-based denoising methods, when qualitative criteria were used. It was shown to improve slightly the subsequent analysis. The automated background removal technique based on thresholding and morphological operations was successful for both noisy and denoised images with a correct removal rate of 85% of the images in the database. The automation of the regions of interest (ROIs) delimitation process was achieved successfully for images with a good contralateral symmetry. Isothermal division complemented well the fixed ROIs division based on dermatomes, giving a more accurate map of potentially abnormal regions. The measure of distance between histograms of comparable ROIs allowed us to increase the sensitivity and specificity rate for the classification of 24 images of pain patients when compared to common statistical comparisons. Conclusions We developed a complete set of automated techniques for the computerised assessment of thermal images to assess pain-related thermal dysfunction.
Collapse
Affiliation(s)
- Christophe L Herry
- Department of Systems and Computer Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Monique Frize
- Department of Systems and Computer Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
- School of Information Technology and Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5, Canada
| |
Collapse
|