Lack of variation in venous tone potentiates vasovagal syncope
Open accessAbstract
OBJECTIVE: To investigate the peripheral venous response to head up tilting in malignant vasovagal syndrome. PATIENTS: 31 Patients with unexplained syncope or dizziness referred from the cardiology department. METHODS: Changes in calf venous volume were studied by a radionuclide technique during 45 degrees head up tilt testing. RESULTS: During tilt testing six patients became syncopal but 25 were symptom free. The syncopal group had greater increases in calf venous volume after the change in posture and perhaps more importantly considerably less variability in the venous volume during the tilted period. CONCLUSIONS: The venous response was different in the syncopal patients. The lack of response of the peripheral venous circulation to changes in the central circulation may be responsible for triggering the Bezold-Jarisch reflex and malignant vasovagal syncope.
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During a vasovagal syncope episode, an ineffective reflex response causes venous pooling in peripheral and/or splanchnic regions.
“During a vasovagal syncope episode, an ineffective reflex response causes venous pooling in the periphery and/or splanchnic regions.73–76”
From 2015 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Treatment of Postural Tachycardia Syndrome, Inappropriate Sinus Tachycardia, and Vasovagal Syncope (2015) · cites this paper as [75]
The Abstract and Discussion report greater calf venous blood volume and less variable venous tone during head-up tilt in patients who fainted. The authors propose that an inadequate peripheral venous response may help trigger syncope, but they do not establish it as a cause or assess splanchnic pooling. They also distinguish this proposed venous abnormality from generalized autonomic dysfunction. (LLM, conf=0.85)
Experimental — accuracy not yet measuredThe underlying pathophysiology of VVS results from a reflex causing hypotension and bradycardia, triggered by prolonged standing or exposure to emotional stress, pain, or medical procedures.
“The underlying pathophysiology of VVS results from a reflex causing hypotension and bradycardia, triggered by prolonged standing or exposure to emotional stress, pain, or medical procedures (361–365).”
From 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope (2017) · cites this paper as [363]
The introductory text (under Abstract, p. 486) describes a reflex culminating in hypotension and bradycardia, and names sight of blood and venepuncture as triggers for a simple faint. The Discussion and tilt-test protocol support a postural trigger, but our copy does not identify emotional stress or pain as triggers, or specifically describe prolonged standing. (LLM, conf=0.86)
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Cites
Mark, A. L. (1983) · Journal of the American College of Cardiology · doi:10.1016/s0735-1097(83)80014-x · Cited by 721 · see citing works
Almquist, A. K., Goldenberg, I. F., Milstein, S., Chen, M. Y., Chen, X., Hansen, R., Gornick, C. C., & Benditt, D. G. (1989) · New England Journal of Medicine · doi:10.1056/nejm198902093200603 · Cited by 643 · see citing works
Lipsitz, L. A., Mietus, J. E., Moody, G. B., & Goldberger, A. L. (1990) · Circulation · doi:10.1161/01.cir.81.6.1803 · Cited by 519 · see citing works
Methodology of head-up tilt testing in patients with unexplained syncope
Fitzpatrick, A. P., THEODORAKIS, G. N., Vardas, P. E., & Sutton, R. (1991) · Journal of the American College of Cardiology · doi:10.1016/0735-1097(91)90714-k · Cited by 428 · see citing works
ÖBerg, B., & Thorén, P. (1972) · Acta Physiologica Scandinavica · doi:10.1111/j.1748-1716.1972.tb05247.x · Cited by 367 · see citing works
ABI‐SAMRA, F. M., Maloney, J. D., Fouad-Tarazi, F. M., & CASTLE, L. W. (1988) · Pacing and Clinical Electrophysiology · doi:10.1111/j.1540-8159.1988.tb03973.x · Cited by 304 · see citing works
TILTING TOWARDS A DIAGNOSIS IN RECURRENT UNEXPLAINED SYNCOPE
Fitzpatrick, A. P., & Sutton, R. (1989) · The Lancet · doi:10.1016/s0140-6736(89)92155-7 · Cited by 254 · see citing works
Role of the Capacitance and Resistance Vessels in Vasovagal Syncope
Epstein, S. E., Stampfer, M., & BEISER, G. D. (1968) · Circulation · doi:10.1161/01.cir.37.4.524 · Cited by 201 · see citing works
Rutlen, D. L., Wackers, F. J. T., & Zaret, B. L. (1981) · Circulation · doi:10.1161/01.cir.64.1.146 · Cited by 168 · see citing works
Come, P. C., & Pitt, B. (1976) · Circulation · doi:10.1161/01.cir.54.4.624 · Cited by 150 · see citing works
The Regulation of the Blood Distribution in Man
Sjöstrand, T. (1952) · Acta Physiologica Scandinavica · doi:10.1111/j.1748-1716.1952.tb00912.x · Cited by 138 · see citing works
Reflex Venomotor Activity in Normal Persons and in Patients with Postural Hypotension
PAGE, E. B., Hickam, J. B., Sieker, H. O., McIntosh, H. D., & Pryor, W. (1955) · Circulation · doi:10.1161/01.cir.11.2.262 · Cited by 136 · see citing works
The head-up tilt table test in patients with syncope of unknown origin
Strasberg, B., Rechavia, E., Sagie, A., Kusniec, J., Mager, A., Sclarovsky, S., & Agmon, J. (1989) · American Heart Journal · doi:10.1016/0002-8703(89)90225-1 · Cited by 133 · see citing works
The Effect of Age on Hemodynamic Response to Graded Postural Stress in Normal Men
Smith, J. J., Hughes, C. V., Ptacin, M. J., Barney, J. A., Tristani, F. E., & Ebert, T. J. (1987) · Journal of Gerontology · doi:10.1093/geronj/42.4.406 · Cited by 74 · see citing works
Cardiovascular Reflex Responses in Patients with Unexplained Syncope
Wahbha, M. M. A. E., MORLEY, C. A., Al-Shamma, Y. M. H., & HAINSWORTH, R. (1989) · Clinical Science · doi:10.1042/cs0770547 · Cited by 63 · see citing works
Grassi, G. M., Gavazzi, C., Cesura, A. M., Picotti, G. B., & Mancia, G. (1985) · Clinical Science · doi:10.1042/cs0680503 · Cited by 46 · see citing works
Profound bradycardia after amyl nitrite in patients with a tendency to vasovagal episodes.
Rosoff, M. H., & Cohen, M. V. (1986) · Heart · doi:10.1136/hrt.55.1.97 · Cited by 27 · see citing works
Effects of Felodipine on Resistance and Capacitance Vessels in Patients with Essential Hypertension
Muir, A., Wathen, C. G., & Hannan, W. J. (1985) · Drugs · doi:10.2165/00003495-198500292-00012 · Cited by 27 · see citing works
Self-citationAcute and chronic arterial and venous effects of captopril in congestive cardiac failure.
Capewell, S., Taverner, D., Hannan, W. J., & Muir, A. L. (1989) · BMJ · doi:10.1136/bmj.299.6705.942 · Cited by 21 · see citing works
Self-citationRotational ablation using the rotablator for angiographically unfavorable lesions
Warth, D. C., Buchbinder, M., O’Neill, W., Zacca, N. M., Bertrand, M. E., Fourrier, J. L., & Erbel, R. M. (1991) · Journal of the American College of Cardiology · doi:10.1016/0735-1097(91)91465-q · Cited by 16 · see citing works
Wathen, C., Hannan, W., Adie, C. J., & Muir, A. (1983) · British Journal of Clinical Pharmacology · doi:10.1111/j.1365-2125.1983.tb02142.x · Cited by 15 · see citing works
Self-citationWilhelmsson, C. (1985) · Drugs · doi:10.2165/00003495-198500291-00001 · Cited by 4 · see citing works
Flagged first, then by citations
Research works printed but not linked: 2
- [9]9. Callahan RJ, Froelich JW, McKusick KA, Leppo J, Strauss HW. A modified method for the in vivo labeling of red blooci cells with Tc-99m: concise communication. J Nucl on August 21, 2023 by guest. Protected by copyright. http://heart.bmj.com/ Br Heart J: first published as 10.1136/hrt.67.6.486 on 1 June 1992. Downloaded from Hargreaves, Muir Med 1982;23:315-8.
- [10]10. Ewing DJ. Recent advances in the non invasive investigation of diabetic neuropathy. In: Bannister R, ed. Autonomic failure. A text of clinical disorders of the autonomic nervous system. 2nd ed. Oxford: Oxford University Press, 1988: 667-89.
Cited by
Sorted by citations
Sheldon, R. S., Grubb, B. P., Olshansky, B., Shen, W.-K., Calkins, H., Brignole, M., Raj, S. R., Krahn, A. D., Morillo, C. A., Stewart, J. M., et al. (2015) · Heart Rhythm · doi:10.1016/j.hrthm.2015.03.029 · Cited by 1,013 · see citing works
2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope
Shen, W.-K., Sheldon, R. S., Benditt, D. G., Cohen, M. I., Forman, D. E., Goldberger, Z. D., Grubb, B. P., Hamdan, M. H., Krahn, A. D., Link, M. S., et al. (2017) · Heart Rhythm · doi:10.1016/j.hrthm.2017.03.004 · Cited by 484 · see citing works
Shen, W.-K., Sheldon, R. S., Benditt, D. G., Cohen, M. I., Forman, D. E., Goldberger, Z. D., Grubb, B. P., Hamdan, M. H., Krahn, A. D., Link, M. S., et al. (2017) · Circulation · doi:10.1161/cir.0000000000000499 · Cited by 453 · see citing works
Shen, W.-K., Sheldon, R. S., Benditt, D. G., Cohen, M. I., Forman, D. E., Goldberger, Z. D., Grubb, B. P., Hamdan, M. H., Krahn, A. D., Link, M. S., et al. (2017) · Circulation · doi:10.1161/cir.0000000000000498 · Cited by 408 · see citing works
The elusive pathophysiology of neurally mediated syncope
Mosqueda-Garcia, R., Furlan, R., MD, J. T., & Fernandez-Violante, R. (2000) · Circulation · doi:10.1161/01.cir.102.23.2898 · Cited by 383 · see citing works
2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope
Shen, W.-K., Sheldon, R. S., Benditt, D. G., Cohen, M. I., Forman, D. E., Goldberger, Z. D., Grubb, B. P., Hamdan, M. H., Krahn, A. D., Link, M. S., et al. (2017) · Journal of the American College of Cardiology · doi:10.1016/j.jacc.2017.03.003 · Cited by 327 · see citing works
Midodrine: a role in the management of neurocardiogenic syncope
Ward, C. R., Gray, J. C., Gilroy, J. J., & Kenny, R. A. (1998) · Heart · doi:10.1136/hrt.79.1.45 · Cited by 249 · see citing works
Autonomic control of the venous system in health and disease: effects of drugs
Pang, C. C. Y. (2001) · Pharmacology & Therapeutics · doi:10.1016/s0163-7258(01)00138-3 · Cited by 219 · see citing works
Raviele, A., Brignole, M., Sutton, R., Alboni, P., Giani, P., Menozzi, C., & Moya, A. (1999) · Circulation · doi:10.1161/01.cir.99.11.1452 · Cited by 201 · see citing works
Baroreflex Sensitivity in Patients With Vasovagal Syncope
Thomson, H. L., Wright, K. N., & Frenneaux, M. P. (1997) · Circulation · doi:10.1161/01.cir.95.2.395 · Cited by 97 · see citing works
Morillo, C. A., Klein, G. J., Jones, D. L., & Yee, R. K. (1994) · The American Journal of Cardiology · doi:10.1016/0002-9149(94)90559-2 · Cited by 96 · see citing works
Decrease in cardiac output and muscle sympathetic activity during vasovagal syncope
Jardine, D. L., Melton, I. C., Crozier, I. G., English, S., Bennett, S. I., Frampton, C. M., & Ikram, H. (2002) · American Journal of Physiology-Heart and Circulatory Physiology · doi:10.1152/ajpheart.00640.2001 · Cited by 86 · see citing works
Dysfunctional Baroreflex Regulation of Sympathetic Nerve Activity in Patients With Vasovagal Syncope
Béchir, M., Binggeli, C., Corti, R., Chenevard, R., Spieker, L. E., Ruschitzka, F. T., Lüscher, T. F., & Noll, G. (2003) · Circulation · doi:10.1161/01.cir.0000056105.87040.2b · Cited by 81 · see citing works
Failure of reflex venoconstriction during exercise in patients with vasovagal syncope
Thomson, H. L., Atherton, J. J., Khafagi, F. A., & Frenneaux, M. P. (1996) · Circulation · doi:10.1161/01.cir.93.5.953 · Cited by 76 · see citing works
Kouakam, C., Lacroix, D., Zghal, N., Logier, R., Klug, D., FRANC, P. L., Jarwé, M., & Kacet, S. (1999) · Heart · doi:10.1136/hrt.82.3.312 · Cited by 71 · see citing works
Murrell, C., Wilson, L. C., Cotter, J. D., Lucas, S. J. E., Ogoh, S., George, K., & Ainslie, P. N. (2007) · Journal of Applied Physiology · doi:10.1152/japplphysiol.01396.2006 · Cited by 63 · see citing works
Mizumaki, K., Fujiki, A., Tani, M., Shimono, M., Hayashi, H., & Inoue, H. (1995) · Journal of the American College of Cardiology · doi:10.1016/0735-1097(95)00120-o · Cited by 61 · see citing works
The venous system is the main determinant of hypotension in patients with vasovagal syncope
Fucă, G., Dinelli, M., Suzzani, P., Scarfo', S., Tassinari, F., & Alboni, P. (2006) · EP Europace · doi:10.1093/europace/eul095 · Cited by 57 · see citing works
Abnormal reflex venous function in patients with neuromediated syncope
Manyari, D. E., Rose, S., Tyberg, J. V., & Sheldon, R. S. (1996) · Journal of the American College of Cardiology · doi:10.1016/0735-1097(96)00051-4 · Cited by 46 · see citing works
PATHOPHYSIOLOGIC BASIS FOR VASODEPRESSOR SYNCOPE
Morillo, C. A., Ellenbogen, K. A., & Pava, L. F. (1997) · Cardiology Clinics · doi:10.1016/s0733-8651(05)70332-5 · Cited by 45 · see citing works
Abnormal Forearm Vascular Responses During Dynamic Leg Exercise in Patients With Vasovagal Syncope
Thomson, H. L., Lele, S. S., Atherton, J. J., Wright, K. N., Stafford, W. J., & Frenneaux, M. P. (1995) · Circulation · doi:10.1161/01.cir.92.8.2204 · Cited by 42 · see citing works
KOCHIADAKIS, G. E., KANOUPAKIS, E. M., Rombola, A. T., Igoumenidis, N. E., CHLOUVERAKIS, G. I., & Vardas, P. E. (1998) · Pacing and Clinical Electrophysiology · doi:10.1111/j.1540-8159.1998.tb00152.x · Cited by 40 · see citing works
Jardine, D. L. (2012) · Cardiology Clinics · doi:10.1016/j.ccl.2012.10.010 · Cited by 38 · see citing works
Kochiadakis, G. E., Kanoupakis, E. M., Igoumenidis, N. E., Marketou, M. E., Solomou, M. C., & Vardas, P. E. (1998) · International Journal of Cardiology · doi:10.1016/s0167-5273(98)00039-4 · Cited by 38 · see citing works
de Chantemèle, E. J. B., Pascaud, L., Custaud, M., Capri, A., Louisy, F., Ferretti, G., Gharib, C., & Arbeille, P. (2004) · The Journal of Physiology · doi:10.1113/jphysiol.2004.069468 · Cited by 30 · see citing works
Contrasting neurovascular findings in chronic orthostatic intolerance and neurocardiogenic syncope
Stewart, J. M., & Weldon, A. (2003) · Clinical Science · doi:10.1042/cs1040329 · Cited by 28 · see citing works
Diagnosis and management of neurally mediated syncope and related conditions in adolescents
Boehm, K. E., Morris, E. J., Kip, K. T., Karas, B. J., & Grubb, B. P. (2001) · Journal of Adolescent Health · doi:10.1016/s1054-139x(00)00153-1 · Cited by 26 · see citing works
Postexercise orthostatic intolerance: influence of exercise intensity
Mündel, T., Perry, B. G., Ainslie, P. N., Thomas, K. N., Sikken, E. L. G., Cotter, J. D., & Lucas, S. J. E. (2015) · Experimental Physiology · doi:10.1113/ep085143 · Cited by 26 · see citing works
Arbeille, P., Kerbeci, P., Mattar, L., Shoemaker, J. K., & Hughson, R. L. (2008) · Journal of Applied Physiology · doi:10.1152/japplphysiol.01021.2007 · Cited by 26 · see citing works
Midodrine Hydrochloride in the Treatment of Vasovagal Syncope
Mitro, P., Trejbal, D., & Rybár, R. (1999) · Pacing and Clinical Electrophysiology · doi:10.1111/j.1540-8159.1999.tb00381.x · Cited by 26 · see citing works
Manganelli, F., Betocchi, S., Ciampi, Q., Storto, G., Losi, M. A., Violante, A., Briguori, C., Tocchetti, C. G., Lombardi, R., Cuocolo, A., et al. (2002) · The American Journal of Cardiology · doi:10.1016/s0002-9149(02)02354-8 · Cited by 23 · see citing works
Bellard, E., Fortrat, J., Custaud, M., Victor, J., GREENLEAF, J. E., & Lefthériotis, G. (2007) · Clinical Autonomic Research · doi:10.1007/s10286-007-0409-0 · Cited by 23 · see citing works
Identical pattern of cerebral hypoperfusion during different types of syncope
Thomas, K. N., Galvin, S., Williams, M. J. A., Willie, C. K., & Ainslie, P. N. (2009) · Journal of Human Hypertension · doi:10.1038/jhh.2009.93 · Cited by 21 · see citing works
Evaluation and Management of Dizziness in the Older Patient
Sloane, P. D. (1996) · Clinics in Geriatric Medicine · doi:10.1016/s0749-0690(18)30201-5 · Cited by 20 · see citing works
Assessment of autonomic function at rest and during tilt testing in patients with vasovagal syncope
KOCHIADAKIS, G. E., Rombola, A. T., Kanoupakis, E. M., SIMANTIRAKIS, E. N., CHLOUVERAKIS, G. I., & Vardas, P. E. (1997) · American Heart Journal · doi:10.1016/s0002-8703(97)70082-6 · Cited by 20 · see citing works
Observations on midodrine in a case of vasodepressor neurogenic syncope
Ward, C., & Kenny, R. A. (1995) · Clinical Autonomic Research · doi:10.1007/bf01818889 · Cited by 18 · see citing works
Skoog, J., Lindenberger, M., Ekman, M., Holmberg, B., Zachrisson, H., & Länne, T. (2015) · American Journal of Physiology-Regulatory, Integrative and Comparative Physiology · doi:10.1152/ajpregu.00362.2015 · Cited by 15 · see citing works
Venous pooling during nitrate-stimulated tilt testing in patients with vasovagal syncope
Koole, M. A. C. (2000) · EP Europace · doi:10.1053/eupc.2000.0116 · Cited by 14 · see citing works
Lord, S., & McComb, J. M. (1996) · Heart · doi:10.1136/hrt.75.2.114 · Cited by 13 · see citing works
Haemodynamic response to peripheral venous congestion in patients with unexplained recurrent syncope
Bellard, E., Fortrat, J., DUPUIS, J.-M., Victor, J., & Lefthériotis, G. (2003) · Clinical Science · doi:10.1042/cs20030061 · Cited by 10 · see citing works
Head-up tilt testing. The balance of evidence.
Hargreaves, A. D., Hag, O. E., & Boon, N. A. (1994) · Heart · doi:10.1136/hrt.72.3.216 · Cited by 10 · see citing works
Self-citationSkoog, J., Zachrisson, H., Länne, T., & Lindenberger, M. (2016) · American Journal of Physiology-Regulatory, Integrative and Comparative Physiology · doi:10.1152/ajpregu.00166.2016 · Cited by 7 · see citing works
Hosaka, H., Takase, B., Kitamura, K., Uehata, A., Satomura, K., Isojima, K., Kosuda, S., Kusano, S., Kurita, A., & Ohsuzu, F. (2001) · Journal of Nuclear Cardiology · doi:10.1067/mnc.2001.116496 · Cited by 7 · see citing works
A “Dysautonomic” Head‐Up Tilt Test Pattern in Elderly Patients with Neurocardiogenic Syncope
Beck, L., Pons, M., Piot, C. A., Leclercq, F., MESSNER-PELLENC, P., Ferrière, M., & Davy, J. (1999) · Pacing and Clinical Electrophysiology · doi:10.1111/j.1540-8159.1999.tb00564.x · Cited by 7 · see citing works
Slower lower limb blood pooling in young women with orthostatic intolerance
Lindenberger, M., & Länne, T. (2014) · Experimental Physiology · doi:10.1113/expphysiol.2014.082867 · Cited by 6 · see citing works
Hou, Z.-Y., Yang, C.-Y., Ko, C.-C., Lee, S. S., Chiang, H.-T., & Chen, C.-Y. (1995) · American Heart Journal · doi:10.1016/0002-8703(95)90144-2 · Cited by 5 · see citing works
Compression Stockings to Combat Vasovagal Syncope: What Is the Rationale?
Madalosso, M., Giada, F., & Raviele, A. (2006) · Springer eBooks · doi:10.1007/88-470-0371-7_84 · Cited by 2 · see citing works
Current Insight on the Pathophysiology of Vasovagal Syncope: What Have We Learned?
Morillo, C. A., & Villar, J. C. (1998) · Springer eBooks · doi:10.1007/978-88-470-2288-1_49 · Cited by 2 · see citing works
Nanda, A., & Sloane, P. D. (2007) · Elsevier eBooks · doi:10.1016/b978-032303930-7.50027-4 · Cited by 1 · see citing works
Vasodepressor syncope: The common faint
Fetzer, S. J. (1999) · Journal of PeriAnesthesia Nursing · doi:10.1016/s1089-9472(99)90006-0 · Cited by 1 · see citing works
Heart Rate Variability in Vasovagal Syncope
KOCHIADAKIS, G. E., & Vardas, P. E. (1998) · Developments in cardiovascular medicine · doi:10.1007/978-94-011-5254-9_20
Wang, C.-H., Cherng, W., & Hung, M. (1998) · International Journal of Cardiology · doi:10.1016/s0167-5273(98)00168-5
Lindenberger, M. (2008) · KTH Publication Database DiVA (KTH Royal Institute of Technology)
Skoog, J. (2016) · Linköping University medical dissertations · doi:10.3384/diss.diva-126942
Fish, E., Lanciano, S. B., Shavit, I., Palacci, H., Chaiat, C., Avivi, I., Kaptsenel, E. H., & Nussinovitch, U. (2021) · Journal of Investigative Medicine · doi:10.1136/jim-2021-001906
- Authors
- Hargreaves, A. D., & Muir, A. L.
- Affiliations
- University of Edinburgh (GB)
- Venue
- Heart
- Publisher
- BMJ
- Published
- 1992-06-01
- Volume
- 67
- Issue
- 6
- Pages
- 486-490
- ISSN
- 1355-6037 (ISSN-L)
- PMC
- PMC1024893
- OpenAlex
- W2133924017
- Cited by
- 55
- References
- 22
- Citations by year
- 2021: 1 · 2017: 4 · 2016: 2 · 2015: 3 · 2014: 1 · 2012: 1
- FWCI
- 2.93
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Heart (publishedVersion)
- PubMed Central (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Surgery › Cardiovascular Syncope and Autonomic Disorders
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Heart Rate Variability and Autonomic Control
- Life Sciences › Neuroscience › Neurology › Vestibular and auditory disorders
- Keywords
- vasovagal syncope, venous tone, head-up tilt, Bezold-Jarisch reflex, dizziness, unexplained syncope
- MeSH terms
- Adolescent, Adult, Age Factors, Aged, Blood Volume, Female, Hemodynamics, Humans, Hypotension, Orthostatic, Leg, Male, Middle Aged, Posture, Regional Blood Flow, Syncope, Veins
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