Email Alert | RSS

Journal of Peking University(Health Sciences) ›› 2019, Vol. 51 ›› Issue (3): 430-438. doi: 10.19723/j.issn.1671-167X.2019.03.009

Previous Articles     Next Articles

Prediction of syncope with nonlinear dynamic analysis during head-up tilt in vasovagal syncope patients

Fan LI1,Han-bin WANG2,Qing PENG1,Yun-chuang SUN1,Ran ZHANG2,Bo PANG2,Jing FANG2,Jue ZHANG2△(),Yi-ning HUANG1△()   

  1. 1. Department of Neurology, Peking University First Hospital, Beijing 100034, China
    2. Academy of Advanced Interdisciplinary Study, Peking University, Beijing 100871, China
  • Online:2019-06-18 Published:2019-06-26

RICH HTML

 12   

PDF (PC)

257

Abstract: Objective: To quantify the relationship between cerebral blood flow velocity and peripheral blood pressure during hypotension period, aiming to predict the brain hypotension before symptomatic occurrence.Methods: Twenty vasovagal syncope (VVS) patients who had a previous clinical history were selected in groups and 20 pair-matched control subjects underwent 70° tilt-up test. The subjects remained supine for 30 minutes before recordings when Doppler probes, electrodes and Finapres device were prepared. After continuous baseline recordings for 10 min, the subjects underwent head up tilt (HUT) test (70°), and were standing upright for 30 minutes or until syncope was imminent. For ethical reasons, the subjects were turned back to supine position immediately after SBP dropped to ≥20 mmHg, when their consciousness persisted. The point of syncope was synchronized for all the subjects by the point SBP reached the minima. Their beat-to-beat blood pressures (BP) were recorded continuously and bilateral middle cerebral artery (MCA) flow velocities were obtained with two 2 MHz Doppler probes from a transcranial Doppler ultrasonography (TCD) system. A nonlinear dynamic method——multimodal pressure flow (MMPF) analysis was introduced to access cerebral autoregulation during different time intervals. We introduced a new indicator——syncope index (SI), which was extracted from blood flow velocity (BFV) signal to evaluate the variation of cerebral vascular tension, and could reflect the deepness of dicrotic notch in BFV signal. Results: Compared with the syncope index of the baseline value at the beginning of the tilt test, SI in VVS group showed significantly lower when the VVS occurred (0.16±0.10 vs.0.27±0.10,P<0.01),while there was no significant difference in syncope index between the control group at the end of the tilt test and the baseline value at the beginning of the tilt test. For those VVS patients, pulse index and resistance index had no significant change. Syncope index decreased significantly 3 minutes before the point of syncope (0.23±0.07 vs.0.29±0.07,P<0.01).Conclusion: Dynamic regulation is exhausted when vasovagal syncope occurred. Tension decrease of small vessels could have some relationship with loss of the cerebral autoregulation capability. The proposed syncope index could be a useful parameter in predicting syncope of VVS patients since it decreased significantly up to 3 minutes earlier from the point of syncope.

Key words: Vasovagal syncope, Cerebral autoregulation, Nonlinear dynamics

CLC Number: 

  • R725.4

Table 1

Baseline characteristics of patients group and control group"

Parameter Patients Control group P
Number of subjects, n 20 20 NA
Age/years 39±12 (19-59) 37±19 (21-76) 0.71
Systolic blood pressure/mmHg 127±19 116±24 0.10
Diastolic blood pressure/ mmHg 75±13 68±13 0.08
Heart rate/(/min) 72±10 68±10 0.32
Mean blood flow velocity/(cm/s) 59±11 58±16 0.77

Figure 1

Dicrotic notch of a typical vasovagal syncope patient during different stage A, supine rest; B, immediate after tilt; C, before syncope point; D, in different stage: supine rest, black line; third last minute before return to supine, red line; second last minute before return to supine, green line; first last minute before return to supine, blue line. A, also showed systolic blood flow velocity(BFV), diastolic BFV and inflexion BFV, definition of pulse velocity and Dicrotic velocity."

Figure 2

Detection of dicrotic notch inflexion point using ensemble empirical mode decomposition A, raw blood flow signal, (+) indicates the detected inflection point; B, intrinsic modes for each component frequencies. The intrinsic mode in red were selected to detect inflexion point, and the inflexion point in the selected mode corresponded to the inflexion point in the raw blood flow velocity signal."

Figure 3

A typical patient fluctuation of blood pressure (BP), blood flow velocity (BFV) and syncope index (SI) during different stage of tilt A, BP and BFV fluctuation, dashed box are time interval from supine rest to second minute after tilt and from 3 minutes before syncope point to syncope point; B, SI during the process from supine rest to second minute after tilt; C, SI during the process from 3 minutes before syncope point to syncope point."

Figure 4

Syncope index reduction relative to baseline in different time periods A, syncope index reduction relative to baseline in control group; B, syncope index reduction relative to baseline in patients group. b, indicates duration of tilt; c, first minute after tilt; d, second minute after tilt; g, last minute before return to supine (vasovagal syncope group); h, Last minutes before the end of the tilt test (control group)."

Table 2

Comparison of physiological parameters between different time periods"

Patients Different time points in tilt test
d e f g
BP-BFV phase shift degree 59.6±20.6 20. 9±17.4# 21.0±12.3# 12.9±9.9#
Syncope index 0.29±0.07 0.23±0.07* 0.19±0.09# 0.16±0.10#
Pulse index 0.81±0.14 0.85±0.13 0.84±0.11 0.89±0.13*
Resistance index 0.52±0.05 0.54±0.05 0.54±0.04 0.55±0.05*

Figure 5

Syncope index, BP-BFV phase shift, pulse index, resistance index in different time period in VVS group A, syncope index; B, phase shift; C, pulse index; D, resistance index.a, indicates last minute before tilt (baseline); b, duration of tilt; c, first minute after tilt; d, indicates second minute after tilt; e, third last minute before return to supine; f, second last minute before return to supine; g, last minute before return to supine; Significant level:*P<0.05,# P<0.01."

[1] Peter N . Cerebral blood flow, heart rate, and blood pressure patterns during the tilt test in common orthostatic syndromes[J]. Neuroscience J, 2016,2016:6127340.
[2] Shen WK, Sheldon RS, Benditt DG , et al. 2017 ACC/AHA/HRS Guideline for the evaluation and management of patients with syncope: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society[J]. Circulation, 2017,136(5):e60-e122.
[3] Brignole M , Moya A, de Lange FJ, et al. 2018 ESC guidelines for the diagnosis and management of syncope[J]. Eur Heart, 2018,39(21):1883-1948.
doi: 10.1093/eurheartj/ehy037
[4] Victor C, Satish R . Confounders of vasovagal syncope: orthostatic hypotension[J]. Cardiol Clin, 2013,31(1):89-100.
doi: 10.1016/j.ccl.2012.09.003
[5] Gommer ED, Shijaku E, Mess WH , et al. Dynamic cerebral autoregulation: different signal processing methods without influence on results and reproducibility[J]. Med Biol Eng Comput, 2010,48(12):1243-1250.
doi: 10.1007/s11517-010-0706-y
[6] Hu K, Peng CK, Huang NE , et al. Altered phase interactions between spontaneous BP and flow fluctuations in type 2 diabetes mellitus: nonlinear assessment of cerebral autoregulation[J]. Physica A, 2008,387(10):2279-2292.
doi: 10.1016/j.physa.2007.11.052
[7] Lo MT, Novak V, Peng CK , et al. Nonlinear phase interaction between nonstationary signals: a comparison study of methods based on Hilbert-Huang and fourier transforms[J]. Phys Rev E Stat Nonlin Soft Matter Phys, 2009,79(6 Pt 1):61924.
doi: 10.1103/PhysRevE.79.061924
[8] Men-Tzung L, Kun H, Yanhui L , et al. Multimodal pressure-flow analysis: application of Hilbert-Huang transform in cerebral blood flow regulation[J]. EURASIP J Adv Signal Process, 2008,2008:785243.
doi: 10.1155/2008/785243
[9] Tiecks FP, Lam AM, Aaslid R , et al. Comparison of static and dynamic cerebral autoregulation measurements[J]. Stroke, 1995,26:1014-1019.
doi: 10.1161/01.STR.26.6.1014
[10] Grubb BP, Gerard G, Roush K , et al. Cerebral vasoconstriction during head-upright tilt-induced vasovagal syncope. A paradoxic and unexpected response[J]. Circulation 1991,84(3):1157-1164.
doi: 10.1161/01.CIR.84.3.1157
[11] Albina G, Cisneros L F, Laiño R , et al. Transcranial Doppler monitoring during head upright tilt table testing in patients with suspected neurocardiogenic syncope[J]. Europace, 2004,6(1):63-69.
doi: 10.1016/j.eupc.2003.09.009
[12] Furukawa T . Role of head-up tilt table testing in patients with syncope or transient loss of consciousness[J]. J Arrhythm, 2017,33(6):568-571.
doi: 10.1016/j.joa.2017.08.002
[13] Carey BJ, Manktelow BN, Panerai R , et al. Cerebral autoregulatory responses to head-up tilt in normal subjects and patients with recurrent vasovagal syncope[J]. Circulation, 2001,104(8):898-902.
doi: 10.1161/hc3301.094908
[14] Subudhi AW, Panerai RB, Roach RC . Acute hypoxia impairs dynamic cerebral autoregulation: results from two independent techniques[J]. J Appl Physiol, 2009,107(4):1165-1171.
doi: 10.1152/japplphysiol.00498.2009
[15] Schondorf R, Stein R, Roberts R , et al. Dynamic cerebral autoregulation is preserved in neurally mediated syncope[J]. Eur J Appl Physiol, 2001,91(5):2493-2502.
doi: 10.1152/jappl.2001.91.6.2493
[16] Krishnamurthy S, Wang X, Bhakta D , et al. Dynamic cardiorespiratory interaction during head-up tilt-mediated presyncope[J]. Am J Physiol Heart Circ Physiol, 2004,287(6):2510-2517.
doi: 10.1152/ajpheart.00485.2004
[17] Wang KW, Chang HH, Hsu CC , et al. Extractions of steady-state auditory evoked fields in normal subjects and tinnitus patients using complementary ensemble empirical mode decomposition[J]. Biomed Eng Online, 2015,14:72.
doi: 10.1186/s12938-015-0062-0
[18] Bondar RL, Kassam MS, Stein F , et al. Simultaneous cerebrovascular and cardiovascular responses during presyncope[J]. Stroke, 1995,26(10):1794-1800.
doi: 10.1161/01.STR.26.10.1794
[19] Schondorf R, Benoit J, Wein T . Cerebrovascular and cardiovascular measurements during neurally mediated syncope induced by head-up tilt[J]. Stroke, 1997,28(8):1564-1568.
doi: 10.1161/01.STR.28.8.1564
[20] Van Lieshout JJ, Wieling W, Karemaker JM , et al. Syncope, cerebral perfusion, and oxygenation[J]. J Appl Physiol, 2003,94(3):833-848
doi: 10.1152/japplphysiol.00260.2002
[21] Bor-Seng-Shu E, Kita WS, Figueiredo EG , et al. Cerebral hemodynamics: concepts of clinical importance[J]. Arq Neuropsiquiatr, 2012,70(5):352-356.
doi: 10.1590/S0004-282X2012000500009
[22] Sweeney MD, Ayyadurai S, Zlokovic BV . Pericytes of the neurovascular unit: key functions and signaling pathways[J]. Nat Neurosci, 2016,19(6):771-783.
[1] Chun-yan TAO,Hong-xia LI,Xue-ying LI,Chao-shu TANG,Hong-fang JIN,Jun-bao DU. Hemodynamic changes in standing-up test of children and adolescents with postural tachycardia syndrome [J]. Journal of Peking University(Health Sciences), 2019, 51(3): 414-421.
[2] . [J]. Journal of Peking University(Health Sciences), 0, (): 749-752.
[3] XU Wen-rui, LIAO Ying, JIN Hong-fang, ZHANG Qing-you, TANG Chao-shu, DU Jun-bao. Progress in diagnosis and management of syncope in children [J]. Journal of Peking University(Health Sciences), 0, (): 756-759.
[4] LIAO Ying, ZHANG Qing-you, LI Hong-xia, WANG Yu-li, LIU Ping, DU Jun-bao. Co-morbidity of vasovagal syncope and postural tachycardia syndrome with allergic diseases in children#br# [J]. Journal of Peking University(Health Sciences), 0, (): 783-788.
[5] . [J]. Journal of Peking University(Health Sciences), 2017, 49(5): 749-752.
[6] XU Wen-rui, LIAO Ying, JIN Hong-fang, ZHANG Qing-you, TANG Chao-shu, DU Jun-bao. Progress in diagnosis and management of syncope in children [J]. Journal of Peking University(Health Sciences), 2017, 49(5): 756-759.
[7] LIAO Ying, ZHANG Qing-you, LI Hong-xia, WANG Yu-li, LIU Ping, DU Jun-bao. Co-morbidity of vasovagal syncope and postural tachycardia syndrome with allergic diseases in children [J]. Journal of Peking University(Health Sciences), 2017, 49(5): 783-788.
[8] QU Yan-Ji, LIU Xiao-Qing, MAI Jin-Zhuang, NIE Zhi-Qiang, 欧Yan-Qiu , GAO Xiang-Min, WU Yong, CHEN Ji-Mei. Analysis of environmental risk factors in congenital heart defects [J]. Journal of Peking University(Health Sciences), 2015, 47(3): 420-430.
Viewed
Full text


Abstract

Cited
  Shared   
  Discussed   
[1] Author. English Title Test[J]. Journal of Peking University(Health Sciences), 2010, 42(1): 1 -10 .
[2] . [J]. Journal of Peking University(Health Sciences), 2009, 41(2): 188 -191 .
[3] . [J]. Journal of Peking University(Health Sciences), 2009, 41(3): 376 -379 .
[4] . [J]. Journal of Peking University(Health Sciences), 2009, 41(4): 459 -462 .
[5] . [J]. Journal of Peking University(Health Sciences), 2010, 42(1): 82 -84 .
[6] . [J]. Journal of Peking University(Health Sciences), 2007, 39(3): 319 -322 .
[7] . [J]. Journal of Peking University(Health Sciences), 2007, 39(3): 333 -336 .
[8] . [J]. Journal of Peking University(Health Sciences), 2007, 39(3): 337 -340 .
[9] . [J]. Journal of Peking University(Health Sciences), 2007, 39(4): 346 -350 .
[10] . [J]. Journal of Peking University(Health Sciences), 2007, 39(4): 351 -354 .
Copyright © Journal of Peking University (Health Sciences), All Rights Reserved.
Powered by Beijing Magtech Co. Ltd