Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-28T13:02:54.292Z Has data issue: false hasContentIssue false
  • English
  • Français

An insight into the autonomic and haemodynamic mechanisms underlying reflex syncope in children and adolescents: a multiparametric analysis

Published online by Cambridge University Press:  23 June 2014

Sérgio Laranjo ,
Cristiano Tavares ,
Mário Oliveira ,
Conceição Trigo ,
Fátima Pinto  and
Isabel Rocha
Sérgio Laranjo*
Affiliation:
Institute of Physiology and Cardiovascular Autonomic Lab, Faculty of Medicine of Lisbon, Lisbon, Portugal Department of Pediatric Cardiology, Santa Marta Hospital, Lisbon, Portugal
Cristiano Tavares
Affiliation:
Institute of Physiology and Cardiovascular Autonomic Lab, Faculty of Medicine of Lisbon, Lisbon, Portugal
Mário Oliveira
Affiliation:
Institute of Physiology and Cardiovascular Autonomic Lab, Faculty of Medicine of Lisbon, Lisbon, Portugal
Conceição Trigo
Affiliation:
Department of Pediatric Cardiology, Santa Marta Hospital, Lisbon, Portugal
Fátima Pinto
Affiliation:
Department of Pediatric Cardiology, Santa Marta Hospital, Lisbon, Portugal
Isabel Rocha
Affiliation:
Institute of Physiology and Cardiovascular Autonomic Lab, Faculty of Medicine of Lisbon, Lisbon, Portugal
*
Correspondence to: Dr S. Laranjo, MD, Cardiovascular Autonomic Function Lab, Instituto de Fisiologia, Faculdade de Medicina de Lisboa, Lisbon, Portugal. Tel: (+351) 217 999 435; E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Around 15% of children and adolescents experience at least one episode of syncope until adulthood. Excluding cardiac disease, the majority of syncopes are of reflex origin and benign in nature. In this situation, a tilt test is conducted to reproduce symptoms and to evaluate cardiovascular adaptations to orthostatism, but its mechanisms are not yet well defined. Here, we investigated haemodynamics and autonomic activity during tilt in young patients. Patients (n=113) with unexplained syncope were enrolled. Tilt followed a standard protocol without provocative agents. A positive response (fainters) was defined as a sudden development of syncope or presyncope associated with hypotension, bradycardia, or both. Haemodynamic parameters, autonomic activity, and baroreflex sensibility were evaluated. Data were analysed on baseline; immediately after tilting; on tilt adaptation; before fainting or before tilt-down for non-fainters; and on tilt-down. A total of 45 patients experienced syncope after a mean time of 18 minutes. During tilting up, fainters showed lower blood pressure and peripheral resistance values, which decreased progressively with time together with baroreflex sensibility. Sympathetic tone increased massively along time till syncope. No changes in cardiac output and heart rate were observed. Results show a strong effort of the autonomic nervous system to adapt to orthostatic stress through different magnitudes of sympathetic output, which was maximal before syncope without apparent modifications of parasympathetic tone. These changes suggest an imbalance between both branches of the autonomic nervous system, not enabling a time-progressive adaptation and leading the subject to faint.

Keywords

Reflex syncopetilt testsympathetic reserveautonomic nervous systembaroreflex
Type
Original Articles
Information
Cardiology in the Young , Volume 25 , Issue 4 , April 2015 , pp. 647 - 654
Copyright
© Cambridge University Press 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Sutton, R, Benditt, D, Brignole, M, Moya, A. Syncope: diagnosis and management according to the 2009 guidelines of the European Society of Cardiology. Polskie Archiwum Medycyny Wewnetrznej 2010; 120: 42–47.Google Scholar
2. Task Force for the Diagnosis and Management of Syncope, European Society of Cardiology, European Heart Rhythm Association et al. Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J 2009; 30: 2631–2671.CrossRefGoogle Scholar
3. Ganzeboom, KS, Mairuhu, G, Reitsma, JB, Linzer, M, Wieling, W, van Dijk, N. Lifetime cumulative incidence of syncope in the general population: a study of 549 Dutch subjects aged 35-60 years. J Cardiovasc Electrophysiol 2006; 17: 1172–1176.Google Scholar
4. Serletis, A, Rose, S, Sheldon, AG, Sheldon, RS. Vasovagal syncope in medical students and their first-degree relatives. Eur Heart J 2006; 27: 1965–1970.CrossRefGoogle ScholarPubMed
5. Colman, N, Nahm, K, Ganzeboom, KS, et al. Epidemiology of reflex syncope. Clin Auton Res 2004; 14 (Suppl 1): 9–17.CrossRefGoogle ScholarPubMed
6. Sheldon, RS, Sheldon, AG, Connolly, SJ, et al. Age of first faint in patients with vasovagal syncope. J Cardiovasc Electrophysiol 2006; 17: 49–54.Google Scholar
7. Forleo, C, Guida, P, Iacoviello, M, et al. Head-up tilt testing for diagnosing vasovagal syncope: a meta-analysis. Int J Cardiol 2013; 168: 27–35.Google Scholar
8. Timoteo, AT, Oliveira, MM, Feliciano, J, et al. Head-up tilt testing with different nitroglycerin dosages: experience in elderly patients with unexplained syncope. Europace 2008; 10: 1091–1094.Google Scholar
9. Ducla-Soares, JL, Santos-Bento, M, Laranjo, S, et al. Wavelet analysis of autonomic outflow of normal subjects on head-up tilt, cold pressor test, Valsalva manoeuvre and deep breathing. Exp Physiol 2007; 92: 677–686.CrossRefGoogle ScholarPubMed
10. Hilz, MJ, Dutsch, M. Quantitative studies of autonomic function. Muscle Nerve 2006; 33: 6–20.Google Scholar
11. Task-Force. Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation 1996; 93: 1043–1065.CrossRefGoogle Scholar
12. Alehan, D, Ayabakan, C, Ozer, S. Heart rate variability and autonomic nervous system changes in children with vasovagal syncope. Pacing Clin Electrophysiol 2002; 25: 1331–1338.Google Scholar
13. Stewart, JM, Erb, M, Sorbera, C. Heart rate variability and the outcome of head-up tilt in syncopal children. Pediatr Res 1996; 40: 702–709.CrossRefGoogle ScholarPubMed
14. Massin, MM, Henrard, V, Gerard, P. Heart rate variability and the outcome of head-up tilt in syncopal children. Acta Cardiol 2000; 55: 163–168.Google Scholar
15. Xavier, R, Laranjo, S, Ducla-Soares, E, et al. The Valsalva maneuver revisited by wavelets. Rev Port Cardiol 2008; 27: 435–441.Google Scholar
16. Tavares, C, Laranjo, S, Santos, M, Rocha, I. An instantaneous time–frequency methodology applied to evaluation of blood pressure changes during HUT of multiple system atrophy patients. Clin Auton Res 2010; 20: 150–151.Google Scholar
17. Souza Neto, EP, Custaud, MA, Cejka, JC, et al. Assessment of cardiovascular autonomic control by the empirical mode decomposition. Methods Inf Med 2004; 43: 60–65.Google Scholar
18. Di Rienzo, M, Parati, G, Castiglioni, P, Tordi, R, Mancia, G, Pedotti, A. Baroreflex effectiveness index: an additional measure of baroreflex control of heart rate in daily life. Am J Physiol Regul Integr Comp Physiol 2001; 280: R744–R751.Google Scholar
19. Iacoviello, M, Guida, P, Forleo, C, Sorrentino, S, D’Alonzo, L, Favale, S. Impaired arterial baroreflex function before nitrate-induced vasovagal syncope during head-up tilt test. Europace 2008; 10: 1170–1175.CrossRefGoogle ScholarPubMed
20. Di Rienzo, M, Parati, G, Castiglioni, P, Tordi, R, Mancia, G, Pedotti, A. Baroreflex effectiveness index: an additional measure of baroreflex control of heart rate in daily life. Am J Physiol Regul Integr Comp Physiol 2001; 280: R744–R751.Google Scholar
21. van Dijk, JG, Wieling, W. Pathophysiological basis of syncope and neurological conditions that mimic syncope. Prog Cardiovasc Dis 2013; 55: 345–356.Google Scholar
22. Verheyden, B, Liu, J, van Dijk, N, et al. Steep fall in cardiac output is main determinant of hypotension during drug-free and nitroglycerine-induced orthostatic vasovagal syncope. Heart Rhythm 2008; 5: 1695–1701.Google Scholar
23. Nowak, JA, Ocon, A, Taneja, I, Medow, MS, Stewart, JM. Multiresolution wavelet analysis of time-dependent physiological responses in syncopal youths. Am J Physiol Heart Circ Physiol 2009; 296: H171–H179.Google Scholar
24. Matsukawa, T, Sugiyama, Y, Mano, T. Age-related changes in baroreflex control of heart rate and sympathetic nerve activity in healthy humans. J Auton Nerv Sys 1996; 60: 209–212.CrossRefGoogle ScholarPubMed
25. Laranjo, S, Oliveira, M, Tavares, C, et al. Tilt training increases vasoconstrictor reserve in patients with refractory neurocardiogenic syncope. Euro Heart J 2010: 262.Google Scholar
26. Laranjo, S, Martins Oliveira, M, Tavares, C, et al. Tilt training increases vasoconstrictor reserve in patients with neurocardiogenic syncope. Rev Port Cardiol 2012; 31: 469–476.Google Scholar
27. Ector, H, Reybrouck, T, Heidbüchel, H, Gewillig, M, Van de Werf, F. Tilt training: a new treatment for recurrent neurocardiogenic syncope and severe orthostatic intolerance. Pacing Clin Electrophysiol 1998; 21: 193–196.CrossRefGoogle ScholarPubMed