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High Skin Sympathetic Nerve Activity in Patients with Recurrent Syncope. J Pers Med 2021; 11:jpm11111053. [PMID: 34834405 PMCID: PMC8620794 DOI: 10.3390/jpm11111053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022] Open
Abstract
(1) Background: The autonomic imbalance plays a role in vasovagal syncope (VVS) diagnosed by head-up tilting test (HUT). neuECG is a new method of recording skin electrical signals to simultaneously analyze skin sympathetic nerve activity (SKNA) and electrocardiogram. We hypothesize that SKNA is higher in subjects with tilt-positive than tilt-negative and the SKNA surges before syncope. (2) Methods: We recorded neuECG in 41 subjects who received HUT (according to the “Italian protocol”), including rest, tilt-up, provocation and recovery phases. Data were analyzed to determine the average SKNA (aSKNA, μV) per digitized sample. Electrocardiogram was used to calculate standard deviation of normal-to-normal beat intervals (SDNN). The “SKNA-SDNN index” was calculated by rest aSKNA multiplied by the ratio of tilt-up to rest SDNN. (3) Results: 16 of 41 (39%) subjects developed syncope. The aSKNA at rest phase is significantly higher in the tilt-positive (1.21 ± 0.27 µV) than tilt-negative subjects (1.02 ± 0.29 µV) (p = 0.034). There are significant surges and withdraw of aSKNA 30 s before and after syncope (both p ≤ 0.006). SKNA-SDNN index is able to predict syncope (p < 0.001). (4) Conclusion: Higher SKNA at rest phase is associated with positive HUT. The SKNA-SDNN index is a novel marker to predict syncope during HUT.
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2
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Electrocardiographic Patterns in Patients with Neurally Mediated Syncope. MEDICINA (KAUNAS, LITHUANIA) 2021; 57:medicina57080808. [PMID: 34441014 PMCID: PMC8399501 DOI: 10.3390/medicina57080808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/27/2022]
Abstract
The baseline electrocardiogram (ECG) is less informative in neurally mediated syncope (NMS) than in arrhythmic syncope. However, some of the ECG patterns present in NMS can have diagnostic and prognostic value in such patients. Electrocardiographic documentation of a syncopal spell and thus identification of the ECG changes can be performed during tilt table test (TTT) or during prolonged ECG monitoring. This work reviews the specific ECG patterns in NMS, which are primarily related to the cardioinhibitory reflex. In addition, there are other ECG findings present in patients with NMS that are being analyzed, such as increased heart rate variability as well as specific QRS voltage patterns. In addition to the diagnostic and prognostic value, these ECG patterns in NMS may help improving the selection of patients for pacemaker implant.
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He Z, Du L, Du S, Wu B, Fan Z, Xin B, Chen X, Fang Z, Liu J. Machine learning for the early prediction of head-up tilt testing outcome. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Buszko K, Kujawski S, Newton JL, Zalewski P. Hemodynamic Response to the Head-Up Tilt Test in Patients With Syncope as a Predictor of the Test Outcome: A Meta-Analysis Approach. Front Physiol 2019; 10:184. [PMID: 30899228 PMCID: PMC6416221 DOI: 10.3389/fphys.2019.00184] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 02/14/2019] [Indexed: 11/13/2022] Open
Abstract
Aim: The paper presents a meta-analysis of studies comparing hemodynamic parameters: heart rate (HR), systolic blood pressure (sBP), diastolic blood pressure (dBP), and stroke volume (SV) measured during head-up tilt table test (HUTT) in patients with positive and negative HUT test outcome. Methods: Pubmed and Clinical Key databases were searched for English-only articles presenting results of biosignals measurements during tilt test in patients suffering from syncope. From 3,289 articles 13 articles published between 1997 and 2015 investigating 892 patients (467 with positive HUTT outcome and 401 with negative one) were selected. Results: There were not statistically significant differences observed between the parameters measured in supine position in patients with positive and negative test outcome [HR (p = 0.86), sBP (p = 0.32), dBP (p = 0.21), SV (p = 0.71)]. In tilt position the parameters HR and SV were significantly different when compared between the two groups of patients [HR (p = 0.02), sBP (p = 0.10), dBP (p = 0.59), SV (p = 0.0004)]. Conclusions: Changes in HR and SV parameters in response to tilt test turned out to be statistically significant. In supine position the differences between patients with positive and negative test outcome were not significant, hence tilt test can be considered as necessary in the diagnosis of vasovagal syndrome.
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Affiliation(s)
- Katarzyna Buszko
- Department of Theoretical Foundations of Bio-Medical Science and Medical Informatics, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland
| | - Sławomir Kujawski
- Division of Ergonomics and Exercise Physiology, Department of Hygiene, Epidemiology and Ergonomics, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Julia L Newton
- The Medical School, Institute for Ageing and Health, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Paweł Zalewski
- Division of Ergonomics and Exercise Physiology, Department of Hygiene, Epidemiology and Ergonomics, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Toruń, Poland
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Buszko K, Piątkowska A, Koźluk E, Fabiszak T, Opolski G. Entropy Measures in Analysis of Head up Tilt Test Outcome for Diagnosing Vasovagal Syncope. ENTROPY 2018; 20:e20120976. [PMID: 33266699 PMCID: PMC7512576 DOI: 10.3390/e20120976] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 11/21/2022]
Abstract
The paper presents possible applications of entropy measures in analysis of biosignals recorded during head up tilt testing (HUTT) in patients with suspected vasovagal syndrome. The study group comprised 80 patients who developed syncope during HUTT (57 in the passive phase of the test (HUTT(+) group) and 23 who had negative result of passive phase and developed syncope after provocation with nitroglycerine (HUTT(−) group)). The paper focuses on assessment of monitored signals’ complexity (heart rate expressed as R-R intervals (RRI), blood pressure (sBP, dBP) and stroke volume (SV)) using various types of entropy measures (Sample Entropy (SE), Fuzzy Entropy (FE), Shannon Entropy (Sh), Conditional Entropy (CE), Permutation Entropy (PE)). Assessment of the complexity of signals in supine position indicated presence of significant differences between HUTT(+) versus HUTT(−) patients only for Conditional Entropy (CE(RRI)). Values of CE(RRI) higher than 0.7 indicate likelihood of a positive result of HUTT already at the passive phase. During tilting, in the pre-syncope phase, significant differences were found for: (SE(sBP), SE(dBP), FE(RRI), FE(sBP), FE(dBP), FE(SV), Sh(sBP), Sh(SV), CE(sBP), CE(dBP)). HUTT(+) patients demonstrated significant changes in signals’ complexity more frequently than HUTT(−) patients. When comparing entropy measurements done in the supine position with those during tilting, SV assessed in HUTT(+) patients was the only parameter for which all tested measures of entropy (SE(SV), FE(SV), Sh(SV), CE(SV), PE(SV)) showed significant differences.
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Affiliation(s)
- Katarzyna Buszko
- Department of Theoretical Foundations of Bio-Medical Science and Medical Informatics, Collegium Medicum, Nicolaus Copernicus University, 85-067 Bydgoszcz, Poland
- Correspondence: ; Tel.: +48-52-585-3428
| | - Agnieszka Piątkowska
- Department of Emergency Medicine, Wroclaw Medical University, 02-091 Wroclaw, Poland
- 1st Department of Cardiology, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Edward Koźluk
- 1st Department of Cardiology, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Tomasz Fabiszak
- Department of Cardiology and Internal Diseases, Collegium Medicum, Nicolaus Copernicus University, 85-067 Bydgoszcz, Poland
| | - Grzegorz Opolski
- 1st Department of Cardiology, Medical University of Warsaw, 02-091 Warsaw, Poland
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Buszko K, Piątkowska A, Koźluk E, Fabiszak T, Opolski G. The complexity of hemodynamic response to the tilt test with and without nitroglycerine provocation in patients with vasovagal syncope. Sci Rep 2018; 8:14554. [PMID: 30266992 PMCID: PMC6162241 DOI: 10.1038/s41598-018-32718-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/10/2018] [Indexed: 11/09/2022] Open
Abstract
The paper presents a comparison of vasovagal syndrome occurrence in a head up tilt table test between patients with a positive result of passive tilt test and those with a positive result after pharmacological provocation. The study group consisted of 80 patients: 57 patients who experienced syncope in the passive phase of the test (43 women (aged: 35.6 ± 16.2) and 14 men (aged: 41.7 ± 15.6) and 23 patients who experienced syncope after pharmacological provocation (17 women (age: 32.3 ± 12) and 6 men (age: 43 ± 15). The main investigation was based on the assessment of monitored signals complexity: heart rate, blood pressure and stroke volume. The analysis of complexity in chosen measurement phases was performed with Sample Entropy. The investigation showed that the reactions of autonomic nervous system during tilt test and before syncope are similar for positive result of passive tilt test and positive result of tilt test with provocation. The differences in supine position occurred only in analysis based on impedance measurement (SV: p = 0.01). Significant differences were denoted for all signals just before the syncope (RRI, sBP, dBP: p = 0,00001 and SV: p = 0.01). In analysis of signals complexity the significant differences occurred just before the syncope for Sample Entropy of blood pressure (SampEn (sBP): p = 0.0008, SampEn (dBP): p = 0,0001).
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Affiliation(s)
- Katarzyna Buszko
- Department of Theoretical Foundations of Bio-Medical Science and Medical Informatics, Collegium Medicum, Nicolaus Copernicus University, 85-067, Bydgoszcz, Poland.
| | - Agnieszka Piątkowska
- Department and Clinic of Emergency Medicine, Wroclaw Medical University, Wroclaw, 50-556, Poland
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, 02-091, Poland
| | - Edward Koźluk
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, 02-091, Poland
| | - Tomasz Fabiszak
- Department of Cardiology and Internal Diseases, Collegium Medicum, Nicolaus Copernicus University, 85-067, Bydgoszcz, Poland
| | - Grzegorz Opolski
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, 02-091, Poland
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Kostoglou K, Schondorf R, Benoit J, Balegh S, Mitsis GD. Prediction of the Time to Syncope Occurrence in Patients Diagnosed with Vasovagal Syncope. ACTA NEUROCHIRURGICA. SUPPLEMENT 2018; 126:313-316. [PMID: 29492581 DOI: 10.1007/978-3-319-65798-1_61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE In this study we aimed to predict the time to syncope occurrence (TSO) in patients with vasovagal syncope (VVS), solely based on measurements recorded during the supine position of the head-up tilt (HUT) testing protocol. METHODS We extracted various time and frequency domain features related to morphological aspects of arterial blood pressure (ABP) and the electrocardiogram (ECG) raw signals as well as to dynamic interactions between beat-to-beat ABP, heart rate, and cerebral blood flow velocity. From these we identified the most predictive features related to TSO. RESULTS Specifically, when no orthostatic stress is involved, TSO in VVS patients can be predicted with high accuracy from a set of only five ECG features.
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Affiliation(s)
- Kyriaki Kostoglou
- Department of Electrical and Computer Engineering, McGill University, Montreal, QC, Canada
| | - Ronald Schondorf
- Department of Neurology, McGill University, Montreal, QC, Canada
| | - Julie Benoit
- Department of Neurology, McGill University, Montreal, QC, Canada
| | - Saharnaz Balegh
- Department of Neurology, McGill University, Montreal, QC, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada.
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Wejer D, Graff B, Makowiec D, Budrejko S, Struzik ZR. Complexity of cardiovascular rhythms during head-up tilt test by entropy of patterns. Physiol Meas 2017; 38:819-832. [PMID: 28263183 DOI: 10.1088/1361-6579/aa64a8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The head-up tilt (HUT) test, which provokes transient dynamical alterations in the regulation of cardiovascular system, provides insights into complex organization of this system. Based on signals with heart period intervals (RR-intervals) and/or systolic blood pressure (SBP), differences in the cardiovascular regulation between vasovagal patients (VVS) and the healthy people group (CG) are investigated. APPROACH Short-term relations among signal data represented symbolically by three-beat patterns allow to qualify and quantify the complexity of the cardiovascular regulation by Shannon entropy. Four types of patterns: permutation, ordinal, deterministic and dynamical, are used, and different resolutions of signal values in the the symbolization are applied in order to verify how entropy of patterns depends on a way in which values of signals are preprocessed. MAIN RESULTS At rest, in the physiologically important signal resolution ranges, independently of the type of patterns used in estimates, the complexity of SBP signals in VVS is different from the complexity found in CG. Entropy of VVS is higher than CG what could be interpreted as substantial presence of noisy ingredients in SBP of VVS. After tilting this relation switches. Entropy of CG occurs significantly higher than VVS for SBP signals. In the case of RR-intervals and large resolutions, the complexity after the tilt becomes reduced when compared to the complexity of RR-intervals at rest for both groups. However, in the case of VVS patients this reduction is significantly stronger than in CG. SIGNIFICANCE Our observations about opposite switches in entropy between CG and VVS might support a hypothesis that baroreflex in VVS affects stronger the heart rate because of the inefficient regulation (possibly impaired local vascular tone alternations) of the blood pressure.
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Affiliation(s)
- Dorota Wejer
- University of Gdańsk, Institute of Experimental Physics, 80-308 Gdańsk, ul Wita Stwosza 57, Poland
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Yoshida M, Ando SI, Eura E, Hayashi A, Kawamura N, Narita S, Matsumoto M, Momii H, Kadokami T, Kiyokawa H. Hemodynamic response during standing test after blood donation can predict the late phase vasovagal reaction. Heart Vessels 2016; 31:1997-2003. [DOI: 10.1007/s00380-016-0829-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 03/25/2016] [Indexed: 11/28/2022]
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10
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Salman IM. Current Approaches to Quantifying Tonic and Reflex Autonomic Outflows Controlling Cardiovascular Function in Humans and Experimental Animals. Curr Hypertens Rep 2016; 17:84. [PMID: 26363932 DOI: 10.1007/s11906-015-0597-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of the autonomic nervous system in the pathophysiology of human and experimental models of cardiovascular disease is well established. In the recent years, there have been some rapid developments in the diagnostic approaches used to assess and monitor autonomic functions. Although most of these methods are devoted for research purposes in laboratory animals, many have still found their way to routine clinical practice. To name a few, direct long-term telemetry recording of sympathetic nerve activity (SNA) in rodents, single-unit SNA recording using microneurography in human subjects and spectral analysis of blood pressure and heart rate in both humans and animals have recently received an overwhelming attention. In this article, we therefore provide an overview of the methods and techniques used to assess tonic and reflex autonomic functions in humans and experimental animals, highlighting current advances available and procedure description, limitations and usefulness for diagnostic purposes.
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Affiliation(s)
- Ibrahim M Salman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia.
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Ho D, Ghods M, Kumar S, Warrier N, Ilias Basha H, Budzikowski AS, Kassotis J. Early Hemodynamic Changes during Head-Up Tilt Table Testing Can Predict a Neurocardiogenic Response in an African-American Patient Population. Cardiology 2015; 133:223-32. [DOI: 10.1159/000441971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/23/2015] [Indexed: 11/19/2022]
Abstract
Background: Head-up tilt table testing (HUTT) is time-consuming and associated with increased patient morbidity. Hemodynamic changes that occur during the early phase of HUTT may be predictive of neurocardiogenic syncope. Methods: A retrospective chart review was performed in 119 consecutive African Americans ( 57 ± 19) who underwent HUTT for evaluation of syncope of unknown etiology. Positive responses were defined as the development of symptoms linked with a systolic blood pressure (BP) <90 mm Hg, heart rate <50 b.p.m. or sinus arrest >3 s. Hemodynamic variables during the passive phase of HUTT were analyzed and results were then classified as a function of various predictors. Results: Sixty-two subjects (52%) had positive HUTT, and 57 (48%) had negative HUTT. Early changes in BP variables from baseline significantly predicted HUTT responses (p < 0.05). There was also a significant interaction between age and BP. An algorithm based on age and BP was developed which had positive and negative predictive values of 67.7 and 93%, respectively, with an accuracy of 79.8%. Conclusion: A novel algorithm utilizing the patients' age and changes in both systolic and diastolic BP during the early phase of HUTT enables the prediction of HUTT results without the use of vasoactive stimulation, allowing for rapid diagnosis, decreased patient morbidity and reduction in costs.
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Klemenc M, Štrumbelj E. Predicting the outcome of head-up tilt test using heart rate variability and baroreflex sensitivity parameters in patients with vasovagal syncope. Clin Auton Res 2015; 25:391-8. [PMID: 26546357 DOI: 10.1007/s10286-015-0318-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 09/18/2015] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of the study was to investigate whether a statistical model could be used for an early prediction of the head-up tilt test (HUTT) outcome from heart rate variability (HRV) and baroreflex sensitivity (BRS) data obtained during early stages of the HUTT. METHODS A modified Italian protocol was used for HUTT in 105 patients with a previous history of vasovagal syncope. Beat-to-beat heart rate and blood pressure were continuously recorded. Fast Fourier transformation was used for spectral analysis of HRV and a sequence technique for measuring the BRS. RESULTS Linear statistical models based on HRV and BRS data from the first 15 min of HUTT were no more accurate than always naively predicted majority class that a syncope will occur (average model out-of-sample accuracy 56.2 ± 5.1 % vs. majority class relative frequency 54.2 %). Even when HRV and BRS data from the first 30 min were used in the model, we did not obtain any predictions of meaningful practical value (75.0 ± 5.1 % accuracy vs. 72.2 % majority class). CONCLUSIONS While there are discernible and meaningful differences between HUTT-P and HUTT-N subjects, they are not sufficient to discriminate between the two groups and predict a syncope early in the HUTT. The results might improve with a larger set of subjects; however, we can conclude that it is not likely that syncope predictions of practical value can be obtained from aggregate HRV spectral analysis and BRS values.
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Affiliation(s)
- Matjaž Klemenc
- Department of Cardiology, General Hospital of Nova Gorica, Padlih borcev 13a, 5290, Šempeter Pri Gorici, Slovenia.
| | - Erik Štrumbelj
- Faculty of Computer Science, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia
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Christou GA, Kouidi EJ, Anifanti MA, Sotiriou PG, Deligiannis AP. A novel strategy for evaluating tilt test in athletes with syncope. Eur J Prev Cardiol 2015; 23:1003-10. [DOI: 10.1177/2047487315600168] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/22/2015] [Indexed: 11/16/2022]
Affiliation(s)
| | - Evangelia J Kouidi
- Laboratory of Sports Medicine, Aristotle University of Thessaloniki, Greece
| | - Maria A Anifanti
- Laboratory of Sports Medicine, Aristotle University of Thessaloniki, Greece
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Couceiro R, Carvalho P, Paiva RP, Muehlsteff J, Henriques J, Eickholt C, Brinkmeyer C, Kelm M, Meyer C. Real-Time Prediction of Neurally Mediated Syncope. IEEE J Biomed Health Inform 2015; 20:508-20. [PMID: 25769176 DOI: 10.1109/jbhi.2015.2408994] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neurally mediated syncope (NMS) patients suffer from sudden loss of consciousness, which is associated with a high rate of falls and hospitalization. NMS negatively impacts a subject's quality of life and is a growing cost issue in our aging society, as its incidence increases with age. In this paper, we present a solution for prediction of NMS, which is based on the analysis of the electrocardiogram (ECG) and photoplethysmogram (PPG) alone. Several parameters extracted from ECG and PPG, associated with reflectory mechanisms underlying NMS in previous publications, were combined in a single algorithm to detect impending syncope. The proposed algorithm was evaluated in a population of 43 subjects. The feature selection, distance metric selection, and optimal threshold were performed in a subset of 30 patients, while the remaining data from 13 patients were used to test the final solution. Additionally, a leave-one-out cross-validation scheme was also used to evaluate the performance of the proposed algorithm yielding the following results: sensitivity (SE)--95.2%; specificity (SP)--95.4%; positive predictive value (PPV)--90.9%; false-positive rate per hour (FPRh)-0.14 h(-1), and prediction time (aPTime)--116.4 s.
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Khodor N, Matelot D, Carrault G, Amoud H, Khalil M, Ville N, Carre F, Hernandez A. Kernel based support vector machine for the early detection of syncope during head-up tilt test. Physiol Meas 2014; 35:2119-34. [PMID: 25243636 DOI: 10.1088/0967-3334/35/10/2119] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study aims to analyze the autonomic nervous system response during head-up tilt test (HUTT), by exploring the changes in dynamic properties of heart rate variability in subjects with and without syncopes, to predict the outcome of HUTT. Baroreflex response, as well as linear and non-linear parameters of RR-interval time series, have been extracted from the ECG of 66 subjects: 35 with and 31 without syncope during HUTT. The results show that, when considering the first 15 min of tilting position, the total power spectrum, the standard deviation, the long-term fractal scale of RR-interval and ΔRR-interval of time series increase, while the sample entropy decreases in the positive group compared to the negative one. These indices may be good predictors of positive response in patients with reflex syncope. Additionally, an analysis of the first 15 min of tilting position using kernel support vector machines leads to a correct classification of 85% of patients, within negative and positive response groups (specificity = 80.6% and sensitivity = 88.5%). In medical applications, it is important to avoid false negative diagnosis of syncopes during HUTT. Taking this into account, an overall accuracy of 72.1% can be obtained in the same window allowing the reduction of the examination time in the clinical domain.
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Affiliation(s)
- N Khodor
- Azm Platform for Research in Biotechnology and its Applications, LASTRE Laboratory, Lebanese University, Tripoli, Lebanon. INSERM, U1099, Rennes, F-35000, France and Université de Rennes 1, LTSI, Rennes, F-35000, France
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Mereu R, De Barbieri G, Perrone T, Mugellini A, Di Toro A, Bernardi L. Heart rate/blood pressure ratio as predictor of neuromediated syncope. Int J Cardiol 2013; 167:1170-5. [DOI: 10.1016/j.ijcard.2012.03.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/03/2012] [Accepted: 03/10/2012] [Indexed: 12/25/2022]
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17
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Early chronotropic response analysis in head up tilt table test. Int J Cardiol 2012; 154:221-2. [DOI: 10.1016/j.ijcard.2011.10.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 10/18/2011] [Indexed: 11/22/2022]
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18
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MEYER CHRISTIAN, MORREN GEERT, MUEHLSTEFF JENS, HEISS CHRISTIAN, LAUER THOMAS, SCHAUERTE PATRICK, RASSAF TIENUSH, PURERFELLNER HELMUT, KELM MALTE. Predicting Neurally Mediated Syncope Based on Pulse Arrival Time: Algorithm Development and Preliminary Results. J Cardiovasc Electrophysiol 2011; 22:1042-8. [DOI: 10.1111/j.1540-8167.2011.02030.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Schroeder C, Tank J, Heusser K, Busjahn A, Diedrich A, Luft FC, Jordan J. Orthostatic tolerance is difficult to predict in recurrent syncope patients. Clin Auton Res 2010; 21:37-45. [PMID: 20924773 DOI: 10.1007/s10286-010-0090-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2010] [Accepted: 09/16/2010] [Indexed: 11/30/2022]
Abstract
OBJECTIVES We tested the hypothesis that detailed anthropometric and hemodynamic measurements predict orthostatic tolerance in neurally mediated syncope patients. In addition, we tested whether orthostatic tolerance is related to syncope frequency in real life. BACKGROUND Earlier studies in patients with neurally mediated syncope suggested that orthostatic heart rate and blood pressure responses predict the tilt table responses with high sensitivity and specificity. METHODS We analyzed data from 157 consecutive patients (n = 100 exploratory cohort, n = 57 confirmatory cohort) with recurrent syncope in whom orthostatic tolerance was quantified as the time to (pre)syncope during head-up tilt testing combined with lower body negative pressure. We measured heart rate, brachial blood pressure, cardiac stroke volume, heart rate and blood pressure variability, and spontaneous baroreflex sensitivity supine and early during head-up tilt. RESULTS The orthostatic heart rate increase showed the strongest correlation with orthostatic tolerance. The best multivariate model including age, supine diastolic blood pressure, supine blood pressure variability, as well as tilt-induced changes in diastolic blood pressure and heart rate explained no more that 40% of the variability in orthostatic tolerance. The model failed to predict orthostatic tolerance in the confirmatory cohort. Frequency or number of free-living syncopal episodes were only weakly related to orthostatic tolerance. CONCLUSIONS In patients with neurally mediated syncope, orthostatic tolerance in the clinical laboratory is difficult to predict with a wide range of anthropometric and cardiovascular measurements and correlates poorly with syncope occurrence in real life.
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Affiliation(s)
- Christoph Schroeder
- Experimental Clinical Research Center, Max-Delbrueck-Centrum for Molecular Medicine, Medical University Charité, Lindenberger Weg 80, Berlin, Germany.
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TURK UGUR, ALIOGLU EMIN, KIRILMAZ BAHADIR, DUYGU HAMZA, TUZUN NURULLAH, TENGIZ ISTEMIHAN, ZOGHI MEHDI, ERCAN ERTUGRUL. Prediction of Head-Up Tilt Test Result: Is it Possible? PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2010; 33:153-8. [DOI: 10.1111/j.1540-8159.2009.02605.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Movahed MR. Predictor of a negative tilt-table test result based on early heart rate variation in patients with a history of syncope. THE AMERICAN HEART HOSPITAL JOURNAL 2007; 5:247-9. [PMID: 17982300 DOI: 10.1111/j.1541-9215.2007.06487.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lack of early sympathetic overreactivity measured by early increase in heart rate has been shown to predict a negative tilt-table (TT) test result. The goal of this study was to evaluate this observation in patients with a history of syncope. The author retrospectively identified 27 patients with a history of syncope undergoing TT testing. The difference between maximal heart rate during the first 10 minutes of the tilting and baseline heart rate was used for early heart rate change. There was a significant association between the probability of a negative TT test result and failure to increase early heart rate over 19 beats per minute. The sensitivity of a negative TT test result was 93.3%, with a specificity of 66.7% (odds ratio, 0.1; confidence interval, 0.14-0.69; P=.001). This study confirms previous findings that failure to increase the heart rate early during a TT test can predict low probability of syncope.
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Affiliation(s)
- Mohammad-Reza Movahed
- Department of Medicine, Division of Cardiology, University of Arizona Sarver Heart Center, Tucson, AZ 85724, USA.
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Virag N, Sutton R, Vetter R, Markowitz T, Erickson M. Prediction of vasovagal syncope from heart rate and blood pressure trend and variability: experience in 1,155 patients. Heart Rhythm 2007; 4:1375-82. [PMID: 17954394 DOI: 10.1016/j.hrthm.2007.07.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Accepted: 07/12/2007] [Indexed: 12/31/2022]
Abstract
BACKGROUND Vasovagal syncope (VVS) is a complex fainting disorder commonly triggered by orthostatic stress. OBJECTIVE We developed an algorithm for VVS prediction based on the joint assessment of RR interval (RR) and systolic blood pressure (SBP). METHODS Simultaneous analysis of RR and SBP trends during head-up tilt as well as their variability represented by low-frequency power (LFRR and LFSBP) generated a cumulative risk that was compared with a predetermined VVS risk threshold. When cumulative risk exceeded the threshold, an alert was generated. Prediction time was the duration between the first alert and syncope. In the first 180 sec of head-up tilt, baseline values were established, following which VVS prediction was possible. An analysis was performed using 1,155 patients who had undergone head-up tilt for syncope: 759 tilt-positive and 396 tilt-negative patients. In the tilt-test protocol, at syncope or after 35 min, the patient was returned to supine. RESULTS In tilt-positive patients, VVS was predicted in 719 of 759 patients (sensitivity 95%), whereas 29 false alarms were generated in 396 tilt-negative patients (specificity 93%). Prediction times varied from 0 to 30 min but were longer than 1 min in 49% of patients. CONCLUSION Predicting impending syncope requires use of simultaneous blood pressure and heart rate, which may shorten diagnostic testing time, free patients from experiencing syncope during a diagnostic tilt-test, and have application in risk-guided tilt training and in an implanted device-to-trigger pacing intervention. The prospects for relieving patient discomfort are encouraging.
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Fortrat JO, Schang D, Bellard E, Victor J, Lefthériotis G. Cardiovascular variables do not predict head-up tilt test outcome better than body composition. Clin Auton Res 2007; 17:206-10. [PMID: 17574505 DOI: 10.1007/s10286-007-0423-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 05/12/2007] [Indexed: 11/25/2022]
Abstract
Reflex syncope is a well-recognized phenomenon, but the understanding of its underlying pathophysiology remains limited. We hypothesized that patients with a history of syncope and a positive head-up tilt test (HUTT) outcome are in a "not-yet defined" abnormal state even before the head-up position. We performed a 45 min HUTT on 86 patients with a history of syncope. We assessed 19 variables during the supine period before head-up position. Of these variables, 9 were cardiovascular variables (CV) while 8 were body composition variables (BC). The two remaining variables were age and sex. Forty-five patients (41 +/- 15 years, 22 males) have a positive HUTT outcome and 41 a negative one (46 +/- 15 years, 22 males). Statistical tests applied on each of the 19 variables individually did not discriminate patients with a positive and a negative outcome. We used neural networks to screen the sets of variables that allowed for the best predictions of HUTT outcomes. The sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) were determined. The best set of predictive values determined from the 19 variables was 76, 81, 78 and 80% for sensitivity, sensibility, PPV, and NPV, respectively. Unexpectedly, the HUTT outcome prediction performed with cardiovascular variables was not better than the prediction performed with body composition variables only. Patients with a positive HUTT outcome are in an abnormal state that can be detected even before the head-up position. Body composition is an important contributor to this abnormal state.
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Affiliation(s)
- Jacques-Olivier Fortrat
- Explorations Fonctionnelles Vasculaires, Centre Hospitalier Universitaire, 49933, Angers Cedex 09, France.
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Bellard E, Fortrat JO, Custaud MA, Victor J, Greenleaf J, Lefthériotis G. Increased hydration alone does not improve orthostatic tolerance in patients with neurocardiogenic syncope. Clin Auton Res 2007; 17:99-105. [PMID: 17464552 DOI: 10.1007/s10286-007-0409-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 02/23/2007] [Indexed: 11/27/2022]
Abstract
In patients with neurocardiogenic syncope, the beneficial effects of increased daily fluid intake, without an accompanying high dose of salt, are unknown. Our aim was to (1) determine whether plasma volume was low in patients with recurrent neurocardiogenic syncope, and (2) determine how recommendation about increased daily fluid intake, without an accompanying high dose of sodium, effects plasma volume and if this potential therapy improves orthostatic tolerance. Eighty-six patients with neurocardiogenic syncope were recruited in a prospective randomized open study. After an initial head-up tilt test, patients were randomly assigned to either the hydration supplementation group (1500 ml of water + 1500 mg of NaCl/day) or the no treatment (control) group. After ten days a second head-up tilt test was performed. Plasma volume, osmolality, and total body water were measured at baseline, and heart rate, arterial blood pressure, and cardiac transthoracic impedance were monitored during tilting. Hydration treatment did not affect the number of positive tilt tests (52% initial day, 54% after treatment, NS). In both groups, the overall number of positive tilt tests decreased between the initial and final head-up tilt test. There was no association between low plasma volume and positive tilt test. Patients with the lowest plasma volume were equally distributed in both positive and negative tilt response groups. An increased daily intake of fluid, without an accompanying high dose of salt, had no measurable beneficial effect on tolerance to head-up tilting in patients with neurocardiogenic syncope. Moreover in this patient group there was no association between a low plasma volume and a reduced tolerance to orthostatic stress.
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Affiliation(s)
- Elisabeth Bellard
- Laboratoire de Physiology, UMR CNRS 6214 Inserm 771, Faculté de Médecine d'Angers rue Haute de Reculée, Angers, France
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Schang D, Feuilloy M, Plantier G, Fortrat JO, Nicolas P. Early prediction of unexplained syncope by support vector machines. Physiol Meas 2006; 28:185-97. [PMID: 17237590 DOI: 10.1088/0967-3334/28/2/007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The goal of the present study was to develop and evaluate a new method for the prediction of unexplained syncope occurrences. Diagnosis of syncope is currently based on the reproduction of symptoms in combination with hypotension and bradycardia induced by a 45 min 60-70 degrees head-upright tilt test (HUTT). The main drawback of this widely used test concerns its duration that reaches 55 min if the patient does not faint. Our method is a first step in the avoidance of the HUTT. An electrocardiogram and a transthoracic impedance waveform were recorded for 10 min of supine rest of a HUTT in 128 patients with a history of unexplained recurrent syncope. Seven indices were computed on the transthoracic impedance and its first derivative. The prediction quality of every subset of these variables, mixed with age and sex, has been tested by a support vector machine in a retrospective group of 64 patients (100% of sensitivity and 100% of specificity was reached). The best subset obtained has been evaluated prospectively in a group of 64 patients (94% of sensitivity and 79% of specificity was reached). These results compare very favorably with published results for other unexplained syncope detectors.
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Affiliation(s)
- Daniel Schang
- ESEO, 4, Rue Merlet de la Boulaye, 49009 Angers Cedex, France.
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26
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Schang D, Bellard E, Plantier G, Dupuis JM, Victor J, Leftheriotis G. Comparison of computational algorithms applied on transthoracic impedance waveforms to predict head-up tilt table testing outcome. Comput Biol Med 2006; 36:225-40. [PMID: 16446157 DOI: 10.1016/j.compbiomed.2004.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Accepted: 09/20/2004] [Indexed: 11/30/2022]
Abstract
The goal of the present study was to develop and evaluate new algorithms for the prediction of the outcome of a head-upright tilt test (HUTT). Using transthoracic impedance and its first derivative, we attempted to determine if indexes computed on these waveforms could detect a positive outcome to a 70 degrees -45min HUTT with reliable sensitivity and specificity. The methods were evaluated retrospectively in a group of 70 patients and validated prospectively in a group of 59 patients. The best detector obtained used a neural network. It compares very favorably with published results for other syncope detectors.
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Affiliation(s)
- D Schang
- Ecole Supérieure d'Electronique de l'Ouest 4, rue Merlet de la Boulaye, P.O. Box 926, 49009 Angers Cedex 01, France.
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García Alberola A, Lacunza Ruiz J, Rojo Álvarez JL, Sánchez Muñoz JJ, Martínez Sánchez J, Requena Carrión J, Barnés J, Valdés M. El incremento temprano de la frecuencia cardíaca no predice el resultado de la prueba de basculación potenciada con nitroglicerina. Rev Esp Cardiol (Engl Ed) 2005. [DOI: 10.1157/13074859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Bellard E, Fortrat JO, Schang D, Dupuis JM, Victor J, Lefthériotis G. Late Hemodynamic Changes During a Negative Passive Head-up Tilt Predict the Symptomatic Outcome to a Nitroglycerin Sensitized Tilt. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2005; 28:89-96. [PMID: 15679637 DOI: 10.1111/j.1540-8159.2005.09250.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Sublingual nitroglycerin is advocated to sensitize the passive 70 degrees head-upright tilt test (HUTT) of patients with unexplained syncope. We hypothesized that a detailed analysis of hemodynamic responses recorded during a negative HUTT could predict the outcome to a subsequent nitroglycerin sensitized HUTT (NTG-HUTT). METHODS Thirty-two patients (46 +/- 3 years, 17 males) with recurrent unexplained syncope but a negative HUTT were included. Heart rate, arterial blood pressure, and central hemodynamics assessed by transthoracic impedance (preejection and rapid left ventricular ejection time, slow ejection time, peak amplitude of first derivative, and cardiac index) were recorded during supine rest and 45 minutes HUTT. Changes from supine rest of the variables were retrospectively compared between patients with a negative (n = 15, NTG-HUTT(-)) and positive (n = 17, NTG-HUTT(+)) outcome to 10 minutes subsequent NTG-HUTT. RESULT Significant differences between groups were observed during the 15th-20th minutes (Italian protocol) and during the last 5 minutes of passive HUTT (Westminster protocol). The combination of cutoff values, determined by receiver operating curves, on hemodynamic variables changes during the last 5 minutes predicted the outcome to a NTG-HUTT with a sensitivity of 76% and a specificity of 87%. The cutoff values determined during 15th-20th minutes gave an attractive sensitivity (85%) but a too weak specificity (53%) to shorten the 45 minutes passive HUTT at 20 minutes. CONCLUSION Outcome to a NTG-HUTT can be reliably predicted by selected criteria determined from multiple hemodynamic variables recorded during a passive 70 degrees HUTT.
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Affiliation(s)
- Elisabeth Bellard
- Laboratoire de Physiologie, Faculté de Médecine, Angers Cedex, France
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Czell D, Schreier R, Rupp R, Eberhard S, Colombo G, Dietz V. Influence of passive leg movements on blood circulation on the tilt table in healthy adults. J Neuroeng Rehabil 2004; 1:4. [PMID: 15679913 PMCID: PMC544951 DOI: 10.1186/1743-0003-1-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Accepted: 10/25/2004] [Indexed: 11/13/2022] Open
Abstract
Background One problem in the mobilization of patients with neurological diseases, such as spinal cord injury, is the circulatory collapse that occurs while changing from supine to vertical position because of the missing venous pump due to paralyzed leg muscles. Therefore, a tilt table with integrated stepping device (tilt stepper) was developed, which allows passive stepping movements for performing locomotion training in an early state of rehabilitation. The aim of this pilot study was to investigate if passive stepping and cycling movements of the legs during tilt table training could stabilize blood circulation and prevent neurally-mediated syncope in healthy young adults. Methods In the first experiment, healthy subjects were tested on a traditional tilt table. Subjects who had a syncope or near-syncope in this condition underwent a second trial on the tilt stepper. In the second experiment, a group of healthy subjects was investigated on a traditional tilt table, the second group on the tilt ergometer, a device that allows cycling movements during tilt table training. We used the chi-square test to compare the occurrence of near-syncope/syncope in both groups (tilt table/tilt stepper and tilt table/tilt ergometer) and ANOVA to compare the blood pressure and heart rate between the groups at the four time intervals (supine, at 2 minutes, at 6 minutes and end of head-up tilt). Results Separate chi-square tests performed for each experiment showed significant differences in the occurrence of near syncope or syncope based on the device used. Comparison of the two groups (tilt stepper/ tilt table) in experiment one (ANOVA) showed that blood pressure was significantly higher at the end of head-up tilt on the tilt stepper and on the tilt table there was a greater increase in heart rate (2 minutes after head-up tilt). Comparison of the two groups (tilt ergometer/tilt table) in experiment 2 (ANOVA) showed that blood pressure was significantly higher on the tilt ergometer at the end of head-up tilt and on the tilt table the increase in heart rate was significantly larger (at 6 min and end of head-up tilt). Conclusions Stabilization of blood circulation and prevention of benign syncope can be achieved by passive leg movement during a tilt table test in healthy adults.
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Affiliation(s)
- David Czell
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Reinhard Schreier
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Rüdiger Rupp
- Orthopaedic Hospital of Heidelberg University, Department II, Heidelberg, Germany
| | - Stephen Eberhard
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Gery Colombo
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- Hocoma AG, Medical engineering, Volketswil, Switzerland
| | - Volker Dietz
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
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Loeppky JA, Icenogle MV, Maes D, Riboni K, Scotto P, Roach RC. Body Temperature, Autonomic Responses, and Acute Mountain Sickness. High Alt Med Biol 2003; 4:367-73. [PMID: 14561242 DOI: 10.1089/152702903769192322] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A few studies have reported increased body temperature (T(o)) associated with acute mountain sickness (AMS), but these usually include exercise, varying environmental conditions over days, and pulmonary edema. We wished to determine whether T(o) would increase with AMS during early exposure to simulated altitude at rest. Ninety-four exposures of 51 men and women to reduced P(B) (423 mmHg = 16,000 ft = 4850 m) were carried out for 8 to 12 h. AMS was evaluated by LL and AMS-C scores near end of exposure, and T(o) was measured by oral digital thermometer before altitude and after 1 (A1), 6 (A6), and last (A12) h at simulated altitude. Other measurements included ventilation, O(2) consumption and autonomic indicators of plasma catecholamines, HR, and HR variability. Average T(o) increased by 0.5 degrees F from A1 to A12 in all subjects (p < 0.001). Comparison between 16 subjects with lowest AMS scores (mean LL = 1.0, range = 0 to 2.5) and 16 other subjects with highest AMS scores (mean LL = 7.4, range = 5 to 11) demonstrated a transient decline in T(o) from A1 to A6 in AMS, in contrast to a rise in non-AMS (p = 0.001). Catecholamines, HR, and HR variability (increased low F/high F ratio) indicated significant elevation of sympathetic activity in AMS, where T(o) fell, but no change in metabolic rate. The apparently greater heat loss during early AMS suggests increased hypoxic vasodilation in spite of enhanced sympathetic drive. Greater hypoxic vasodilation and elevated HR in AMS in the absence of other changes suggest that augmentation of beta-adrenergic tone may be involved in early AMS pathophysiology.
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Affiliation(s)
- Jack A Loeppky
- Cardiology Section (111B), VA Medical Center, Albuquerque, NM, USA.
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Pitzalis M, Parati G, Massari F, Guida P, Di Rienzo M, Rizzon B, Castiglioni P, Iacoviello M, Mastropasqua F, Rizzon P. Enhanced reflex response to baroreceptor deactivation in subjects with tilt-induced syncope. J Am Coll Cardiol 2003; 41:1167-73. [PMID: 12679218 DOI: 10.1016/s0735-1097(03)00050-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVES We sought to evaluate whether changes in resting baroreflex control of heart rate are a distinctive feature of healthy subjects with a history of syncope prone to a positive tilt-test response. BACKGROUND The mechanisms involved in the pathogenesis of vasovagal syncope (VVS) are still poorly understood; in particular, the contribution of arterial baroreflex control of heart rate is matter of discussion. METHODS A passive tilt-table test was performed in 312 consecutive, otherwise healthy subjects (age 36 +/- 15 years) with unexplained syncope and 100 control subjects. At baseline, spontaneous baroreflex sensitivity (BRS; ms/mm Hg) and the baroreflex effectiveness index (BEI) were assessed using the sequence method. RESULTS The study population showed normal baroreflex function. Tilt-induced VVS in 94 subjects who were younger than both the tilt-negative and control subjects (30 +/- 14, 38 +/- 15, and 37 +/- 14 years, respectively; p = 0.00005) showed greater BRS (17.4 +/- 9.8, 13.2 +/- 7.9, and 12.8 +/- 8.2 ms/mm Hg, respectively; p = 0.0001), but had a similar BEI (0.59 +/- 0.18, 0.56 +/- 0.19, and 0.58 +/- 0.2, respectively; p = NS). On Cox multivariate analysis, the occurrence of VVS during tilt was inversely related to age (hazard ratio 0.97; p = 0.0004) and directly related to the BRS slope of sequences, implying a baroreceptor deactivation (hazard ratio 1.05; p = 0.02), but not of sequences characterized by arterial baroreceptor stimulation. CONCLUSIONS Subjects with tilt-induced VVS showed greater resting BRS but had a normal BEI. The enhanced reflex tachycardic response to arterial baroreceptor deactivation at rest may represent a characteristic feature of subjects prone to tilt-induced VVS.
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Bellard E, Fortrat JO, Vielle B, Dupuis JM, Victor J, Lefthériotis G. Early predictive indexes of head-up tilt table testing outcomes utilizing heart rate and arterial pressure changes. Am J Cardiol 2001; 88:903-6, A8. [PMID: 11676960 DOI: 10.1016/s0002-9149(01)01904-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- E Bellard
- Laboratory of Physiology, Medical School of Angers, Angers, France
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Sumiyoshi M, Nakata Y, Mineda Y, Tokano T, Yasuda M, Nakazato Y, Yamaguchi H. Does an early increase in heart rate during tilting predict the results of passive tilt testing? Pacing Clin Electrophysiol 2000; 23:2046-51. [PMID: 11202245 DOI: 10.1111/j.1540-8159.2000.tb00774.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Head-up tilt testing is a useful but time-consuming procedure. If we could accurately predict the tilt testing results; we would be able to substantially shorten the duration of tilt protocol. To clarify the hypothesis that an early increase in heart rate (HR) during tilting can predict the passive tilt results in our protocol (80-degree angle for 30 minutes), we studied 115 consecutive patients (72 men, 43 women, mean age 46 +/- 19 years) who were clinically diagnosed with neurally mediated syncope. Twenty-nine (25%) patients had a positive tilt test (P group), whereas 86 (75%) patients had a negative test (N group). The early HR increase was defined as the maximum HR during the first 5 minutes of tilting minus the resting HR before tilting. The early HR increase was significantly higher in the P group (23.8 +/- 9.5 beats/min) than in the N group (17.5 +/- 8.2 beats/min, P = 0.0008), but it was negatively correlated with the tilt duration to positive response (r = -0.52, P = 0.0032) and the patient age in the entire study population (r = 0.62, P < 0.0001). Results of multiple regression analysis indicated that age, tilt result, and tilt duration were independently associated with the early HR increase. As a result, an early HR increase > or = 18 beats/min, the best apparent cut-off point obtained in our study, was a sensitive (100%) marker for prediction of a positive response at < or = 15 minutes of tilting, but it showed a low specificity (61%). In conclusion, an early HR increase during 80-degree tilting may be only predictive for a positive result < or = 15 minutes because it depends on the tilt duration to a positive response and patient age.
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Affiliation(s)
- M Sumiyoshi
- Department of Cardiology, Juntendo University School of Medicine, Tokyo
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Kim JS, Park JE, Seo JD, Lee WR, Kim HS, Noh JI, Kim NS, Yum MK. Decreased entropy of symbolic heart rate dynamics during daily activity as a predictor of positive head-up tilt test in patients with alleged neurocardiogenic syncope. Phys Med Biol 2000; 45:3403-12. [PMID: 11098913 DOI: 10.1088/0031-9155/45/11/321] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Entropy measures of RR interval variability during daily activity over a 24h period were compared in 30 patients with a positive head-up tilt (HUT) test and 30 patients with a negative HUT test who had a history of alleged neurocardiogenic syncope. Two different entropies, approximate entropy (ApEn) and entropy of symbolic dynamics (SymEn), were employed. In patients showing a positive HUT test, the entropies were significantly decreased when compared with the patients with a negative HUT test. In addition, SymEn in the patients with a negative HUT test was significantly lower than in the normal controls. Discriminant analysis using SymEn could correctly identify 89.3% (520/582) of the 1 h RR interval data of the patients with a positive HUT test regardless of the time of day. Baseline entropies of heart rate dynamics during daily activity were found to be significantly lower in patients with alleged neurocardiogenic syncope and a positive HUT test than in those with the same history but with a negative HUT test. The decreased entropy of symbolic heart rate dynamics may be of predictive value of a positive HUT test in patients with alleged neurocardiogenic syncope.
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Affiliation(s)
- J S Kim
- Department of Medicine, Sungkyunkwan University School of Medicine, Cardiac and Vascular Center, Samsung Medical Center, Korea
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Shen WK, Low PA, Rea RF, Lohse CM, Hodge DO, Hammill SC. Distinct hemodynamic profiles in patients with vasovagal syncope: a heterogeneous population. J Am Coll Cardiol 2000; 35:1470-7. [PMID: 10807449 DOI: 10.1016/s0735-1097(00)00567-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The objective was to investigate mechanisms of vasovagal syncope by identifying laboratory techniques that characterize cardiovascular profiles in patients with vasovagal syncope. BACKGROUND The triggering mechanisms of vasovagal syncope are complex. The patient population is likely heterogeneous. We hypothesized that distinct hemodynamic profiles are definable with provocative maneuvers. METHODS Three groups of subjects were matched for age and gender: 16 patients with a history of syncope and an inducible vasovagal response during passive tilt table testing (70 degrees, 45 min, group I), 16 with a history of syncope, negative passive tilt table testing but positive isoproterenol tilt table testing (0.05 microg/kg per min, 70 degrees, 10 min, group II), and 16 control subjects. Beat-to-beat hemodynamic functions were determined noninvasively by photo-plethysmography and impedance cardiography. RESULTS At baseline, hemodynamic functions were not different among the three groups (supine). In response to tilt before any symptoms developed, total peripheral resistance decreased 9% +/- 14% in group I from baseline supine to tilt position but increased 27% +/- 18% in group II and 28% +/- 17% in controls (p < 0.001). Responses to isoproterenol were not significantly different between group II and controls in supine position. In response to tilt during isoproterenol infusion before any symptoms developed, total peripheral resistance decreased 24% +/- 20% in group II and increased 20% +/- 48% in controls (p = 0.002). CONCLUSIONS Group I patients may have impaired ability to increase vascular resistance during orthostatic stress. The inability to overcome isoproterenol-induced vasodilatation during tilt is important in triggering a vasovagal response in group II patients. These data suggest that the population with vasovagal response is heterogeneous. Distinct hemodynamic profiles in response to various provocative maneuvers are definable with noninvasive, continuous monitoring techniques.
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Affiliation(s)
- W K Shen
- Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA
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Alvarez JB, Asensio E, Lozano JE, Alvarez M, Portos JM. Early heart rate variations during head-up tilt table testing as a predictor of outcome of the test. Pacing Clin Electrophysiol 2000; 23:26-31. [PMID: 10666750 DOI: 10.1111/j.1540-8159.2000.tb00646.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Head-up tilt table testing (HUTT) is a useful tool for the diagnosis of unknown origin of syncope. A setback is its duration. This study tries to establish a specific parameter that, according to the heart rate elevation in the test's initial phase, allows a reliable prediction of its outcome. In a prospective study, every patient being under unknown syncope workup was included. A two-phase 20-minute tilt table test was performed. The initial phase was passive, and the second required pharmacological stimulation with isoproterenol. The basal and 5- and 10-minute heart rate values of the passive phase were measured and compared within the group and against negative tests. During a 1-year period, 115 HUTT were performed: 88 were positive and 27 negative. The negative HUTT patients had an increase in HR of 5.05 (+/- 13.5) beats/min at 5 minutes, and 5.79 (+/- 12.9) beats/min at 10 minutes (P = 0.2). Those with a positive HUTT had an increase of 9.05 (+/- 14.5) beats/min at 5 minutes, and of 10 (+/- 13.4) beats/min at 10 minutes (P < 0.001). There were no significant changes in HR when comparing positive to negative HUTT. There is no specific number that allows predication of outcome early in HUTT. Within the group, variations are important. Only a group tendency can be established, which strongly correlates with the results obtained during the test.
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Affiliation(s)
- J B Alvarez
- Servicio de Cardiología, Hospital Español de México, D.F., México.
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Beck L, Pons M, Piot C, Leclercq F, Messner-Pellenc P, Ferrière M, Davy JM. A "dysautonomic" head-up tilt test pattern in elderly patients with neurocardiogenic syncope. Pacing Clin Electrophysiol 1999; 22:1004-12. [PMID: 10456628 DOI: 10.1111/j.1540-8159.1999.tb00564.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The characteristics of neurocardiogenic syncope (NCS) in elderly patients remain unclear. We compared the hemodynamic profiles of young and older patients with consecutive and positive head-up tilt tests (HUT). Continuous, noninvasive, and reliable monitoring of arterial pressure (AP) and heart rate (HR) was done throughout 46 consecutive positive HUTs of symptomatic patients. The population (12-82 years old) was divided into two groups: younger patients, Y (n = 25, < or = 65 years), and older patients, O (n = 21). Changes in AP and HR after the first minute of tilting, during the stable orthostatic phase and during syncope were compared. Except for systolic pressure, baseline hemodynamic parameters were similar in Y and O. No difference appeared in the mean time elapsed before syncope (19+/-9 vs 22+/-2 min). Asymptomatic hypotension was observed, only in O, 1 minute after tilting, followed by a progressive fall in the mean AP before syncope (0+/-0.9 vs -1+/-0.7 mmHg/min) without HR increase (0.7+/-1 vs 0+/-0.6 beats/min). This pressure slope was strongly related to age (r = 0.54, P < 0.001). Hemodynamic recording during HUT identifies a dysautonomic pattern in elderly patients with NCS and the abnormal AP/HR responses to orthostasis may be a feature specific to this population. Although the central mechanism of NCS is common to all ages, the age-related characteristics of the trigger event may indicate the need for specific management at different ages.
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Affiliation(s)
- L Beck
- Cardiologie, Hôpital Arnaud de Villeneuve, Montpellier, France
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