scholarly journals Cerebral perfusion responses to active standing are attenuated in patients with vasovagal syncope

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
L Perez-Denia ◽  
P Claffey ◽  
A O"reilly ◽  
M Delgado-Ortet ◽  
C Rice ◽  
...  
Keyword(s):  
Recovery Rate ◽  
Cerebral Autoregulation ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Vasovagal Syncope ◽  
Young Patients ◽  
Community Dwelling ◽  
Cerebral Hypoperfusion ◽  
Convenience Sample

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Irish Research Council (IRC): Government of Ireland Postgraduate Scholarship Programme 2018, Dublin, Ireland Fundació Universitària Agustí Pedro i Pons, Universitat de Barcelona, Barcelona, Spain Background Syncope is a transient loss of consciousness due to cerebral hypoperfusion. While traditionally peripheral haemodynamics are monitored during clinical assessment of syncope, relatively little is known about cerebrovascular haemodynamics during orthostasis in patients with syncope. Purpose Here we investigated whether young patients with syncope present an altered cerebral perfusion when compared to healthy controls. Given potential hyper-reactivity of the autonomic nervous system previously reported in these patients, we hypothesise that an overly active cerebral autoregulation will be present in patients with syncope. Methods Consecutive patients were prospectively recruited from a National Falls and Syncope Unit, and a convenience sample of young healthy community dwelling adults was recruited from a local university (16-30 years). Participants performed a 3 minute active stand test with continuous measurement of beat-to-beat peripheral haemodynamics (blood pressure (BP), heart rate (HR)) and changes in concentration of oxygenated Δ[O2Hb] and deoxygenated Δ[HHb] haemoglobin were derived from a near-infrared spectroscopy (NIRS) monitor. Baseline, steady state and other time domain features were derived for Δ[O2Hb] (nadir, overshoot, overshoot-to-nadir, overshoot-to-nadir recovery rate) and Δ[HHb] (peak, trough, peak-to-trough, peak-to-trough recovery rate) and multiple linear regression was used to compare differences between the two groups correcting for covariates (p < 0.05 significant). Results Patients (n = 40) were younger (20(5.5) vs 23(1) years, p = 0.003) than controls (n = 17) and were well matched in gender, weight, height, BMI and resting haemodynamics. Patients had a smaller Δ[O2Hb] overshoot-to-nadir difference (β: -0.749, CI:(-1.593 0.094), p = 0.08), a slower Δ[O2Hb] recovery rate (β: -0.186, CI:(-0.388 0.016), p = 0.071), and smaller Δ[HHb] peak-to-trough difference (β: -0.530, CI:( -0.921 0.138), p = 0.018) and slower Δ[HHb] recovery rate (β: -0.151, CI: (0.244 0.057), p = 0.008). Conclusion Patients with syncope had signs of an attenuated cerebral oxygenation response to an AS when compared to controls. We hypothesise that this is due to hyper-reactive cerebral autoregulation mechanism, which might be related to a hyper-sensitive autonomic system. Furthering our understanding of vasovagal syncope physiology can help inform future interventions and treatments. This study shows the clinical value of measuring cerebral perfusion using NIRS, an easy to use and readily applicable tool, in the assessment of syncope. Abstract Figure. Cerebral oxygenation upon standing

P5678Near-infrared spectroscopy (NIRS) in the evaluation of psychogenic pseudosyncope - Moving towards a simplified diagnostic pathway

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
P Claffey ◽  
L Perez-Denia ◽  
G Rivasi ◽  
A Ungar ◽  
C Finucane ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Diagnostic Yield ◽  
Case Series ◽  
Cerebral Hypoperfusion ◽  
Tilt Test ◽  
Eyes Closed ◽  
Unexplained Syncope

Abstract Background Psychogenic pseudosyncope (PPS) is a conversion disorder that often mimics syncope, is commonly referred to cardiology clinics and accounts for a large proportion of patients admitted with “unexplained syncope”. Unlike syncope, PPS is characterized by normal blood pressure (BP) and heart rate (HR) values at TLOC inferring the absence of cerebral hypoperfusion. The current gold standard for the diagnosis of PPS is the reproduction of patients' symptoms during a head-up tilt test (HUTT) with concurrent electroencephalogram (EEG) monitoring showing normal haemodynamic and brainwave measurements. However, EEG is time consuming, resource intensive and many syncope units lack ready access, thereby solely relying on absence of peripheral haemodynamic changes to diagnose PPS. Purpose Near-infrared spectroscopy (NIRS) is a non-invasive technology used for continuous monitoring of cerebral oxygenation. Measuring adequacy of tissue oxygenation is an appropriate surrogate for cerebral perfusion. In this study, we present a case series of patients for whom the diagnosis of PPS was confirmed by NIRS during TLOC. We propose use of NIRS in routine clinical assessment of suspected PPS. Methods We describe nine consecutive patients with suspected PPS referred to a dedicated syncope unit for investigation of recurrent unexplained syncope. All patients underwent evaluation in accordance with European Society of Cardiology guidelines including HUTT. Continuous beat-to-beat BP and HR measurements were recorded using finger plethysmography. In addition, continuous NIRS-derived tissue saturation index (TSI) - a measure of percentage oxygenation - was recorded using an optical sensor applied to the left lateral forehead to assess cerebral perfusion. Absolute values of BP, HR and TSI at baseline, time of first symptom onset, presyncope and apparent TLOC were recorded. The evaluation was diagnostic for PPS when apparent TLOC occurred in the absence of typical haemodynamic or cerebral perfusion changes. Results The median age was 35 years (range 14–54). Clinical features were consistent with those previously described in PPS literature - female preponderance, comorbid psychiatric diagnosis, frequent attack history, with prolonged TLOC and eyes closed during events. During HUTT, all patients experienced an apparent TLOC which they recognised as reproductive of typical events. BP and HR measurements increased significantly at time of TLOC. There was no significant change in TSI at any of the time points throughout HUTT. (Figure 1 shows averaged absolute values of systolic and diastolic BP, HR and TSI with median values represented by thickened lines.) Figure 1. Measurements during HUTT Conclusion NIRS is readily available, easily accessible and provides an appropriate surrogate measure of cerebral perfusion during HUTT. We propose that HUTT incorporating concurrent NIRS monitoring will enhance diagnostic yield and patient management providing important biofeedback.

scholarly journals Do patients with syncope have a hyper-reactive autonomic nervous system?

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
L Perez-Denia ◽  
P Claffey ◽  
A O"reilly ◽  
M Delgado-Ortet ◽  
C Rice ◽  
...  
Keyword(s):  
Nervous System ◽  
Steady State ◽  
Autonomic Nervous System ◽  
Recovery Rate ◽  
Community Dwelling ◽  
Cerebral Hypoperfusion ◽  
Control Group ◽  
Convenience Sample ◽  
Treatment Pathways ◽  
Autonomic Nervous

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Irish Research Council (IRC): Government of Ireland Postgraduate Scholarship Programme 2018, Dublin, Ireland Fundació Universitària Agustí Pedro i Pons, Universitat de Barcelona, Barcelona, Spain. Background The origin of syncope, a transient loss of consciousness due to cerebral hypoperfusion, remains unclear. Recent studies suggest that a hypersensitive autonomic nervous system might be involved in the pathophysiology of vasovagal syncope (VVS). Purpose Here we test the hypothesis that patients with VVS have a hyper-reactive autonomic nervous system by investigating the peripheral haemodynamic responses during a standing (AS) test in a group of young VVS patients vs a control group. Methods A prospective sample of consecutive patients from a National Falls and Syncope Unit was recruited, and a convenience sample of young healthy community dwelling adults was recruited from a local university (16-30 years). Participants performed a 3 minute AS with continuous measurement of beat-to-beat blood pressure (BP), heart rate (HR), and cerebral oxygenation measured with near infrared spectroscopy. Baseline, steady-state and other time domain features were obtained for systolic BP (SBP) (i.e. nadir, overshoot, overshoot-to-nadir, overshoot-to-nadir recovery rate) and for HR (i.e. peak, trough, peak-to-trough, peak-to-trough recovery rate). Multiple linear regression was used to compare these features between patients and controls while correcting for covariates (p < 0.05 significant). Results Forty patients and 17 controls were included, the former group being younger ((20(5.5) vs 23(1) years, p = 0.003). During steady-state standing SBP was higher as compared to controls (β: 6.853, CI: (0.713 12.993), p = 0.029). Patient data trended toward lower steady-state HR (β: -5.262, CI:(-11.201 0.677), p = 0.081), together with a larger peak-to-trough difference (β: 7.212, CI:(1.329 -15.754), p = 0.096). Conclusion These results tend to support the hypothesis and previous literature suggesting the presence of autonomic hyper-reactivity in patients with syncope, presenting as an exaggerated peripheral circulatory response to standing. Understanding the pathophysiology of VVS can help us improve its assessment and develop better treatment pathways for these patients. Abstract Figure.

Syncope, cerebral perfusion, and oxygenation

2003 ◽  
Vol 94 (3) ◽  
pp. 833-848 ◽  
Author(s):  
Johannes J. Van Lieshout ◽  
Wouter Wieling ◽  
John M. Karemaker ◽  
Niels H. Secher
Keyword(s):  
Cardiac Output ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Vasovagal Syncope ◽  
Low Frequencies ◽  
Healthy Humans ◽  
Standing Up ◽  
Arterial Inflow ◽  
Cerebral Blood Velocity ◽  
Critical Reduction

During standing, both the position of the cerebral circulation and the reductions in mean arterial pressure (MAP) and cardiac output challenge cerebral autoregulatory (CA) mechanisms. Syncope is most often associated with the upright position and can be provoked by any condition that jeopardizes cerebral blood flow (CBF) and regional cerebral tissue oxygenation (cO2Hb). Reflex (vasovagal) responses, cardiac arrhythmias, and autonomic failure are common causes. An important defense against a critical reduction in the central blood volume is that of muscle activity (“the muscle pump”), and if it is not applied even normal humans faint. Continuous tracking of CBF by transcranial Doppler-determined cerebral blood velocity ( Vmean) and near-infrared spectroscopy-determined cO2Hb contribute to understanding the cerebrovascular adjustments to postural stress; e.g., MAP does not necessarily reflect the cerebrovascular phenomena associated with (pre)syncope. CA may be interpreted as a frequency-dependent phenomenon with attenuated transfer of oscillations in MAP to Vmeanat low frequencies. The clinical implication is that CA does not respond to rapid changes in MAP; e.g., there is a transient fall in Vmeanon standing up and therefore a feeling of lightheadedness that even healthy humans sometimes experience. In subjects with recurrent vasovagal syncope, dynamic CA seems not different from that of healthy controls even during the last minutes before the syncope. Redistribution of cardiac output may affect cerebral perfusion by increased cerebral vascular resistance, supporting the view that cerebral perfusion depends on arterial inflow pressure provided that there is a sufficient cardiac output.

Near-infrared spectroscopy in evaluation of cerebral oxygenation during vasovagal syncope

2004 ◽  
Vol 25 (4) ◽  
pp. 823-836 ◽  
Author(s):  
E Szufladowicz ◽  
R Maniewski ◽  
E Kozluk ◽  
A Zbiec ◽  
A Nosek ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Vasovagal Syncope

scholarly journals Hyperspectral Near Infrared Assessment Of The Brain In Cardiac Arrest

2021 ◽  
Author(s):  
Thu Nga Nguyen
Keyword(s):  
Cardiac Arrest ◽  
Oxygen Saturation ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Cerebral Hypoperfusion ◽  
Invasive Technique ◽  
Breath Holding ◽  
Transcatheter Aortic Valve ◽  
Neurological Injuries ◽  
The Brain

Two-thirds of out-of-hospital cardiac arrest patients, who survive to hospital admission, die in the hospital from neurological injuries related to cerebral hypoperfusion. Hyperspectral near infrared spectroscopy (hNIRS) is a non-invasive technique that measures the major chromophores in the brain, such as oxygenated hemoglobin, deoxygenated hemoglobin and cytochrome C oxidase (CCO), an intracellular marker of oxygen consumption. We have demonstrated that hNIRS can detect changes in cerebral oxygenation and metabolism in patients undergoing transcatheter aortic valve insertion (TAVI) – a procedure that temporarily induces sudden hypotension and hypoperfusion that mimics cardiac arrest. Using multi-distance hNIRS, we found that while measured regional oxygen saturation (rSO2) changes resulted mainly from the extra-cerebral tissues, CCO changes during cardiac arrests occurred mainly in the brains of patients. We also applied the hNIRS algorithm based on the “2-layer model” to the data to measure cerebral oxygen saturation and CCO in patients during the procedure. We found that changes in all the parameters scale with the thickness of the extra-cerebral layer. Finally, the results of the comparison of breath holding measurement by using multispectral NIRS algorithm with the selected wavelength combinations from a previous study on animal suggests that changes in CCO could be measured, however wavelengths need to be further optimized for the adult patients.

scholarly journals Impaired Stabilisation of Orthostatic Cerebral Oxygenation is Associated with Slower Gait Speed: Evidence from The Irish Longitudinal Study on Ageing

2021 ◽  
Author(s):  
John D O'Connor ◽  
Matthew D L O’Connell ◽  
Silvin P Knight ◽  
Louise Newman ◽  
Orna A Donoghue ◽  
...  
Keyword(s):  
Older Adults ◽  
Longitudinal Study ◽  
Gait Speed ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Saturation Index ◽  
Small Sample ◽  
Community Dwelling ◽  
Clinical Tool ◽  
Wide Range

Abstract Background Cerebral autoregulation (CAR) systems maintain blood flow to the brain across a wide range of blood pressures. Deficits in CAR have been linked to gait speed but previous studies had small sample sizes and used specialised equipment which impede clinical translation. The purpose of this work was to assess the association between gait speed and orthostatic cerebral oxygenation in a large, community-dwelling sample of older adults. Methods Data for this study came from the Irish Longitudinal Study on Ageing. A near infrared spectroscopy (NIRS) device attached to the forehead of each participant (n=2708) was used to track tissue saturation index (TSI; the ratio of oxygenated to total haemoglobin) during standing. Gait speed (GS) was assessed using a portable walkway. Results Recovery was impaired in slower GS participants with a TSI value at 20 seconds (after standing) of -0.55% (95% CI: -0.67, -0.42) below baseline in the slowest GS quartile versus -0.14% (95% CI: -0.25, -0.04) in the fastest quartile. Slower GS predicted a lower TSI throughout the 3-minute monitoring period. Results were not substantially altered by adjusting for orthostatic hypotension. Adjustment for clinical and demographic covariates attenuated the association between but differences remained between GS quartiles from 20 seconds to 3 minutes after standing. Conclusion This study reported evidence for impaired recovery of orthostatic cerebral oxygenation depending on gait speed in community-dwelling older adults. Future work assessing NIRS as a clinical tool for monitoring the relationship between gait speed and cerebral regulation is warranted.

scholarly journals Near-infrared spectroscopy in evaluating psychogenic pseudosyncope—a novel diagnostic approach

QJM ◽  
2019 ◽  
Vol 113 (4) ◽  
pp. 239-244
Author(s):  
P Claffey ◽  
L Pérez-Denia ◽  
G Rivasi ◽  
C Finucane ◽  
R A Kenny
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Saturation Index ◽  
Diagnostic Algorithm ◽  
Cerebral Hypoperfusion ◽  
P Value ◽  
Non Invasive ◽  
Eyes Closed

Abstract Background Psychogenic pseudosyncope (PPS), a conversion disorder and syncope mimic, accounts for a large proportion of ‘unexplained syncope’. PPS is diagnosed by reproduction of patients’ symptoms during head-up tilt (HUT). Electroencephalogram (EEG), a time consuming and resource intensive technology, is used during HUT to demonstrate absence of cerebral hypoperfusion during transient loss of consciousness (TLOC). Near-infrared spectroscopy (NIRS) is a simple, non-invasive technology for continuous monitoring of cerebral perfusion. We present a series of patients for whom PPS diagnosis was supported by NIRS during HUT. Methods Eight consecutive patients with suspected PPS referred to a syncope unit underwent evaluation. During HUT, continuous beat-to-beat blood pressure (BP), heart rate (HR) and NIRS-derived tissue saturation index (TSI) were measured. BP, HR and TSI at baseline, time of first symptom, presyncope and apparent TLOC were measured. Patients were given feedback and followed for symptom recurrence. Results Eight predominantly female patients (6/8, 75%) aged 31 years (16–54) were studied with (5/8, 63%) having comorbid psychiatric diagnoses, and (5/8, 63%) presenting with frequent episodes of prolonged TLOC with eyes closed (6/8, 75%). All patients experienced reproduction of typical events during HUT. Systolic BP (mmHg) increased from baseline (129.7 (interquartile range [IQR] 124.9–133.4)) at TLOC (153.0 (IQR 146.7–159.0)) (P-value = 0.012). HR (bpm) increased from baseline 78 (IQR 68.6–90.0) to 115.7 (IQR 93.5–127.9) (P-value = 0.012). TSI (%) remained stable throughout, 71.4 (IQR 67.5–72.9) at baseline vs. 71.0 (IQR 68.2–73.0) at TLOC (P-value = 0.484). Conclusions NIRS provides a non-invasive surrogate of cerebral perfusion during HUT. We propose HUT incorporating NIRS monitoring in the diagnostic algorithm for patients with suspected PPS.

Older Adults’ Drop in Cerebral Oxygenation on Standing Correlates With Postural Instability and May Improve With Sitting Prior to Standing

2020 ◽  
Author(s):  
Laura K Fitzgibbon-Collins ◽  
George A Heckman ◽  
Ikdip Bains ◽  
Mamiko Noguchi ◽  
William E McIlroy ◽  
...  
Keyword(s):  
Older Adults ◽  
Postural Stability ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Center Of Pressure ◽  
Postural Instability ◽  
Cerebral Hypoperfusion ◽  
Total Path Length ◽  
Increased Risk ◽  
Cerebral Tissue Oxygenation

Abstract Background Impaired blood pressure (BP) recovery with orthostatic hypotension on standing occurs in 20% of older adults. Low BP is associated with low cerebral blood flow but mechanistic links to postural instability and falls are not established. We investigated whether posture-related reductions in cerebral tissue oxygenation (tSO2) in older adults impaired stability upon standing, if a brief sit before standing improved tSO2 and stability, and if Low-tSO2 predicted future falls. Method Seventy-seven older adults (87 ± 7 years) completed (i) supine–stand, (ii) supine–sit–stand, and (iii) sit–stand transitions with continuous measurements of tSO2 (near-infrared spectroscopy). Total path length (TPL) of the center of pressure sway quantified stability. K-cluster analysis grouped participants into High-tSO2 (n = 62) and Low-tSO2 (n = 15). Fall history was followed up for 6 months. Results Change in tSO2 during supine–stand was associated with increased TPL (R = −.356, p = .001). When separated into groups and across all transitions, the Low-tSO2 group had significantly lower tSO2 (all p < .01) and poorer postural stability (p < .04) through 3 minutes of standing compared to the High-tSO2 group. There were no effects of transition type on tSO2 or TPL for the High-tSO2 group, but a 10-second sitting pause improved tSO2 and enhanced postural stability in the Low-tSO2 group (all p < .05). During 6-month follow-up, the Low-tSO2 group had a trend (p < .1) for increased fall risk. Conclusions This is the first study to show an association between posture-related cerebral hypoperfusion and quantitatively assessed instability. Importantly, we found differences among older adults suggesting those with lower tSO2 and greater instability might be at increased risk of a future fall.

scholarly journals Evaluation of cerebral oxygenation and perfusion in small for gestational age neonates and neurodevelopmental outcome at 24–36 months of age

2020 ◽  
Vol 48 (3) ◽  
pp. 280-288
Author(s):  
Eleni Milona ◽  
Dimitrios Rallis ◽  
Georgios Mitsiakos ◽  
Evanthia Goutsiou ◽  
Elias Hatziioannidis ◽  
...  
Keyword(s):  
Gestational Age ◽  
Small For Gestational Age ◽  
Cerebral Perfusion ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Late Onset ◽  
Composite Index ◽  
Neurodevelopmental Outcome ◽  
Significant Risk ◽  
Neurodevelopmental Outcomes

AbstractObjectiveTo examine cerebral oxygenation and perfusion in small for gestational age (SGA) compared with appropriate for gestational age (AGA) neonates during the first postnatal week, and to investigate any association with neurodevelopmental outcomes at 24–36 months of age.MethodsA prospective matched case-control study was conducted evaluating cerebral oxygenation and perfusion, using near-infrared spectroscopy (NIRS), between SGA and AGA neonates, during the first postnatal week. A neurodevelopmental assessment with Bayley-III was performed at 24–36 months of age.ResultsForty-eight SGA and 48 AGA neonates of similar gestation (32.8 ± 2.1 vs. 32.5 ± 1.9) were enrolled. On the first postnatal day, the cerebral oxygenation was equal between SGA and AGA neonates (71 ± 7% vs. 72 ± 8%); however, in the subgroup analysis, males had higher oxygenation compared to female SGA neonates (73 ± 7% vs. 69 ± 7%, P = 0.04). Cerebral perfusion was significantly higher in SGA neonates on the first postnatal day (1.4 ± 0.6 vs. 1.1 ± 0.5, P = 0.04), but this difference was diminished on subsequent measurements. There were no significant differences between the SGA and AGA infants regarding the composite cognitive, communication and motor index scores. The length of mechanical ventilation and late-onset sepsis were significant risk factors affecting the cognitive and communication composite index scores, respectively.ConclusionCerebral oxygenation was equal between SGA and AGA neonates, while cerebral perfusion was transiently increased in SGA neonates during the first postnatal day. There was no significant association of cerebral oxygenation and perfusion with neurodevelopmental outcomes.

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