- Neurocardiogenic syncope is a temporary loss
of consciousness associated with a drop in
arterial blood pressure, quickly followed by a
slowed heart rate (Grubb & McMann, 2001, p.
- Neurocardiogenic syncope (NCS) is also
referred to as vasovagal syncope or neurally
mediated syncope. The terms are used
interchangeably throughout this web
- What are the symptoms of NCS?
- Neurocardiogenic fainting usually occurs
while standing. Emotional stress, stressful
condition and pain may trigger an episode,
especially among the young (Shah, Gupta &
Lokhandwala, 2003). The onset may be abrupt or
associated with warning symptoms such as
fatigue, weakness, nausea, sweating, pallor,
visual disturbances, abdominal discomfort,
headache, pins-and-needles, lightheadedness or
vertigo (Deering, 2003). Presyncopal patients
may also complain of palpitations, vomiting,
disorientation, and difficulty speaking clearly
or coherently (Grubb & McMann, 2001, p.
60.). Other symptoms that may present before a
faint include feeling either warm or cold,
having a bluish/purple or red coloring to the
skin (Alboni, Brignole, Menozzi, Raviele, Del
Rosso, Dinelli, Solano & Bottoni,
- During the faint "seizure-like" activity may
occur (Grubb, Gerard & Roush, 1991). This
convulsive activity is thought to be distinct
from a seizure disorder.
- Patients are sometimes symptomatic after a
faint as well. Patients may complain of symptoms
including nausea, clamminess, lightheadedness,
headache and malaise (Deering, 2003). Patients
may also experience vomiting, abdominal
discomfort, weakness, tremors, cold or warm
feelings and confusion (Alboni et al., 2001).
Patients who experience frequent
neurocardiogenic syncope may report symptoms
between faints as well, such as chronic fatigue,
headache, chest pain, exercise intolerance,
heart "flip flops" and an inability to tolerate
- Mechanisms and causes of NCS
- When a person stands up, the pull of gravity
causes blood to pool in the lower extremities.
This can result in a lack of blood supply to the
upper body, including the heart and brain.
Normally, the body automatically adjusts to the
lack of blood supply by increasing vascular
tone, heart rate and cardiac output. Blood
vessels contract, heart rate increases, systolic
blood pressure remains about the same or drops
slightly while diastolic pressure rises slightly
(Brunner & Suddarth, 2000, p. 546).
- In those with neurocardiogenic syncope this
compensatory mechanism does not always work
correctly. The exact mechanisms of NCS are not
completely understood, and several theories have
been proposed. Many physicians hold a general
consensus as to what is happening during NCS as
- The strong contractions of the ventricle
walls are thought to cause a response in the
mechanoreceptors, which misinterpret what is
happening and send a message to the brain that
the blood pressure is actually high. In
response, the sympathetic portion of the
cardiovascular center reduces its impulses to
the heart and blood vessels while the
parasympathetic division increases its impulses
(Grubb & McMann, 2001, p. 61-62). This
abnormal nervous system reflex causes the heart
to slow and the blood vessels to dilate (open
up), further lowering blood pressure (North
American Society of Pacing and
Electrophysiology, 1999). Because of this faulty
adjustment, NCS patients may experience
- A 2004 research publication suggests
patients may awaken from sleep with symptoms of
forthcoming neurocardiogenic syncope (Krediet,
Jardine, Cortelli, Visman & Wieling, 2004).
This suggestion may seem to contradict current
teachings on this disorder. However, research
shows that transient autonomic mechanisms that
predispose to vasovagal syncope may occur during
sleep (Shneerson, 2000, p. 1-15).
- So what are some of the factors that may be
contributing to the faulty adjustment thought to
result in neurocardiogenic syncope?
- Differential changes in plasma levels of
epinephrine, renin, endothelin, vasopressin,
cortisol, prolactin, beta endorphins and
substance P have been reported by some
investigators either prior to or during a
syncopal episode in patients with vasovagal
syncope (Ellenbogen, Morillo, Wood, Gilligan,
Eckberg & Smith, 1997). Further research has
shown that galanin may play a role in one's
ability to adapt to orthostatic stress.
- Serotonin may be involved in the
pathogenesis of NCS as well. Studies in animals
have shown that the withdrawal of sympathetic
impulses correlates with a higher level of
serotonin being present in the central nervous
system, the brain and the spinal cord (Grubb
& McMann, 2001, p. 57).
- Another study showed that young women who
had vasovagal syncope with a positive tilt test
result had a greater sensitivity to insulin.
Insulin, in addition to its known metabolic
effects, has sympatho-excitatory and
vasodilatory actions on muscular blood vessels.
The authors of this study conclude that insulin
hypersensitivity could be one of the
predisposing factors for vasovagal episodes
(Ruiz, Calvar, Hermes, Rivadeneira, Bengolea,
Chirife, Tentori & Gelpi, 2003).
- How is NCS diagnosed?
- Tilt table testing is often used to diagnose
NCS. However, tilt table testing can have
false-negative and false-positive results
- How is NCS treated?
- There are a variety of non-pharmacutical
methods used to control and prevent
neurocardiogenic syncope. No single therapy has
been found to be effective in all patients.
Non-pharmacutical therapies used to treat NCS
include the following:
- Cardioneuroablation reportedly has helped
some neurocardiogenic syncope patients, although
the study reporting this was small and patients
had only been followed up for 9 months at the
time of publishing (Pachon, Pachon, Pachon,
Lobo, Pachon, Vargas & Jatene, 2005).
Further investigation is warranted.
- Counter-maneuvers may help some patients
with neurocardiogenic syncope. Isometric arm
counter-pressure maneuvers can increase systolic
blood pressure and prevent fainting in some
patients with NCS (Brignole, Croci, Menozzi,
Solano, Donateo, Oddone, Puggioni & Lolli,
2002). Patients can perform isometric arm
counter-pressure maneuvers by gripping one had
with the other and pushing both arms away from
- Leg crossing combined with muscle tensing at
the onset of prodromal symptoms can postpone,
and in some instances prevent, vasovagal syncope
(Krediet, van Dijk, Linzer, van Lieshout &
- Sitting with the head between the knees
often is an effective means of preventing
syncope (Mathias, 2003).
- One patient has reported success in warding
off a fainting episode by gently but briskly
stepping in place for a short time, bringing the
knees a little upward and puffing out the exhale
with each rep. Pumping the arms and fists during
this counter-maneuver has helped her as
- Increasing dietary salt and fluid intake may
help prevent symptoms associated with
neurocardiogenic syncope (Bloomfield,
- Orthostatic self-training and tilt training
may help select patients with NCS (Abe, Kondo,
Kohshi, Nakashima, 2002). Orthostatic
self-training involves standing against a wall,
without moving, twice a day for a planned
duration of up to 30 minutes.
- Tilt training involves inclining patients on
a tilt table each day. Some patients have to
continually be inclined for this therapy to be
effective. This therapy will not be effective in
all patients. However, one study showed that in
19 patients who abandoned tilt training after
about 1 year, none of them reported fainting
during daily life. The authors of this study
hypothesize that the disturbed autonomic reflex
activity may have been restored in these
patients (Reybrouck, Heidbuchel, Van De Werf
& Ector, 2002).
- Paced breathing may help to prevent
vasovagal syncope induced by head-up tilt test.
Researchers who studied the effects of paced
breathing believe respiratory training could be
useful in the prevention of vasovagal syncope
(Jauregui-Renaud, Marquez, Hermosillo, Sobrino,
Lara, Kostine & Cardenas, 2003).
- Removal or avoidance of agents that
predispose to hypotension or dehydration can
lessen the occurance of neurocardiogenic syncope
(Bloomfield, 2002). Situations that can
predispose an individual to syncope are listed
on the POTS Place "What to Avoid" page.
- There are a variety of medications and
medical treatments that may help prevent
neurocardiogenic syncope as well. These include
- ACE inhibitors may prevent NCS, presumably
through inhibition of sympathetic system
activation and the peripheral hypotensive effect
(Zeng, Zhu, Liu, Hu, Wang, Yang, Wang, He &
- Alpha-agonists increase venous tone and
decrease pooling, which may prevent activation
of mechano-receptors. They also counteract the
arteriolar vasodilation produced by the
triggering of the vasovagal reflex (Raviele,
Themistoclakis & Gasparini, 1996, p. 115).
Midodrine is an example of an alpha-agonist that
is used to treat NCS. Midodrine has been shown
to significantly improve orthostatic tolerance
during head-up tilt in patients with recurrent
neurally mediated syncope (Kaufmann, Saadia
& Voustianiouk, 2002).
- Beta blockers have been reported in many
studies to be effective in treating
neurocardiogenic syncope. Presumably, these
agents exert their effects through their
negative inotropic actions, which are felt to
diminish the degree of cardiac mechano-receptor
activation or by acting elsewhere to oppose the
high levels of circulating epinephrine (Raviele,
Themistoclakis & Gasparini, 1996, p. 114).
However, studies of the efficacy of beta
blockers in treating NCS have had mixed results.
One study showed that propranolol, nadolol and
placebo were all equally effective in treating
vasovagal syncope (Flevari, Livanis,
Theodorakis, Zarvalis, Mesiskli &
Kremastinos, 2002). The physicians conducting
this study concluded that beta blockers are no
better than placebo at reducing neurocardiogenic
- Another study showed nonselective beta
blockers to be more effective than
beta-1-selective blockers in preventing
tilt-induced syncope (Dendi & Goldstein,
- Calcium Channel Blockers may be effective in
some patients with NCS. However, in a study
comparing verapamil (a calcium channel blocker)
to metoprolol (a beta blocker), verapamil was
found to be less effective in the management of
neurocardiogenic syncope (Jhamb, Singh, Sharda,
Kaul, Goel, Talwar & Wasir, 1996).
- Disopyramide has negative inotropic and
anticholinergic effects that may be potentially
beneficial in preventing vasovagal syncope by
decreasing ventricular contractibility and
counteracting parasympathetic activity (Raviele,
Themistoclakis & Gasparini, 1996, p.
- Fludrocortisone is sometimes used to prevent
neurocardiogenic syncope. There is considerable
clinical experience and a consensus suggesting
that fludrocortisone is effective (Bloomfield,
- Pacemakers are a somewhat controversial
treatment for neurocardiogenic syncope. Many
studies have suggested the efficacy of
pacemakers. However, a double-blind randomized
trial showed that pacing therapy did not reduce
the risk of recurrent syncope in patients with
vasovagal syncope. The authors of this study
concluded that pacemaker therapy should not be
recommended as a first-line therapy for patients
with recurrent vasovagal syncope (Connolly,
Sheldon, Thorpe, Roberts, Ellenbogen, Wilkoff
& Morillo, 2003).
- Scopolamine may be effective in reducing the
high vagal tone that occurs during syncopal
episodes (Raviele, Themistoclakis &
Gasparini, 1996, p. 115).
- Serotonin Reuptake Inhibitors may prevent
NCS by reducing the sympathetic impulses that
signal the heart to contract more strongly
(Grubb & McMann, 2001, p. 115).
- Theophylline is an adenosine receptor
blocker. It may prevent NCS, although patients
sometimes discontinue theophylline because of
adverse reactions (Nelson, Stanley, Love, Coyne
& Schaal, 1991). Theophylline is not
generally used as a first line treatment for
- Patients sometimes need a combination of
medications to prevent recurrent
- 1. Abe, H., Kondo, S., Kohshi, K.,
Nakashima, Y. (2002). Usefulness of
- orthostatic self-training for the prevention
of neurocardiogenic syncope.
- Pacing & Clinical Electrophysiology,
25(10), 1454-1458. Pubmed
- 2. Alboni, P., Brignole, M., Menozzi, C.,
Raviele, A., Del Rosso, A., Dinelli,
- Solano, A., & Bottoni N. (2001).
Diagnostic value of history in patients
- with syncope with or without heart disease.
Journal of the American
- College of Cardiology, 37, 1921-1928.
- 3. Bloomfield, D. M. (2002). Strategy for
the management of vasovagal syncope.
- Drugs & Aging, 19(3), 179-202.
- 4. Brignole, M., Croci, F., Menozzi, C.,
Solano, A., Donateo, P., Oddone, D.,
- Puggioni, E. & Lolli, G. (2002).
Isometric arm counter-pressure maneuvers
- to abort impending vasovagal syncope.
Journal of the American College
- of Cardiology, 40(11), 2053-2059.
- 5. Brunner, L. S. & Suddarth, D. S.
(2000). Assessment of cardiovascular
- function. In S. C. Smeltzer & B. G. Bare
(Eds.), Brunner and Suddarth's
- textbook medical-surgical nursing (pp.
532-563). Philadelphia, PA:
- Lippincott Williams and Wilkins.
- 6. Connolly, S. J., Sheldon, R., Thorpe, K.
E., Roberts, R. S., Ellenbogen, K. A.,
- Wilkoff, B. L., Morillo, C., &
Gent, M. (2003). Pacemaker therapy
- for prevention of syncope in patients with
recurrent severe vasovagal
- syncope: Second Vasovagal Pacemaker Study
(VPS II): a randomized trial.
- Journal of the American Medical Association,
- 7. Deering, A. (2003). Cheltenham Syncope
Clinic. Retrieved May 15, 2003.
- 8. Dendi, R., & Goldstein, D. S. (2002).
Meta-analysis of nonselective versus
- beta-1 adrenoceptor- selective blockade in
prevention of tilt-induced
- neurocardiogenic syncope. American Journal
of Cardiology, 89(11),
- 1319-1321. PubMed
- 9. Ellenbogen, K. A., Morillo, C. A., Wood,
M. A., Gilligan, D. M., Eckberg,
- D. L., Smith, M. L. (1997). Neural
monitoring of vasovagal syncope.
- Pacing & Clinical Electrophysiology.
20(3 Pt 2), 788-794. PubMed
- 10. Flevari, P., Livanis, E. G.,
Theodorakis, G. N., Zarvalis, E., Mesiskli,
- Kremastinos, D. T. (2002). Vasovagal
syncope: a prospective, randomized,
- crossover evaluation of the effect of
propranolol, nadolol and placebo
- on syncope recurrence and patients'
well-being. Journal of the American
- College of Cardiology, 40(3), 499-504.
- 11. Grubb, B. P., Gerard, G., Roush, K.
(1991 ). Differentiation of convulsive
- syncope and epilepsy with head up tilt table
testing. Annals of Internal
- Medicine, 117, 871-876. PubMed
- 12. Grubb, B. P. & McMann, M. C. (2001).
The fainting phenomenon:
- Understanding why people faint and what can
be done about it. New
- York: Futura Publishing Company, Inc.
- 13. Jauregui-Renaud, K., Marquez, M. F.,
Hermosillo, A. G., Sobrino, A., Lara,
- J. L., Kostine, A., Cardenas, M.
(2003). Paced breathing can prevent
- vasovagal syncope during head-up tilt
testing. Journal Canadien de
- Cardiologie, 19(6), 698-700. PubMed
- 14. Jhamb, D. K., Singh, B., Sharda,
B., Kaul, U., Goel, P., Talwar, K. K.,
- Wasir, H. S. (1996). Comparative study of
the efficacy of metoprolol and
- verapamil in patients with syncope and
positive head-up tilt test response.
- American Heart Journal, 132(3), 608-611.
- 15. Kaufmann, H., Saadia, D., Voustianiouk,
A. (2002). Midodrine in neurally
- mediated syncope: a double-blind,
randomized, crossover study.
- Annals of Neurology, 52(3), 342-345.
- 16. Krediet, C. T., van Dijk, N., Linzer,
M., van Lieshout, J. J., Wieling, W.
- (2002). Management of vasovagal syncope:
controlling or aborting faints by
- leg crossing and muscle tensing.
Circulation, 106(13), 1684-1689.
- 17. Krediet, C. T., Jardine, D. L.,
Cortelli, P., Visman, A. G., Wieling, W.
- (2004). Vasovagal syncope interrupting
sleep? Heart, 90(5), e25. PubMed
- 18. Levine, M. M. (1999). Neurally mediated
syncope in children: results of tilt
- testing, treatment, and long-term follow-up.
Pediatric Cardiology, 20(5),
- 331-335. PubMed
- 19. Mathias, C. J. (2003). Autonomic
diseases: management. Journal of
- Neurology, Neurosurgery & Psychiatry. 74
Suppl 3:iii, 42-47.
- Full Text:
- 20. Nelson, S. D., Stanley, M., Love, C. J.,
Coyne, K. S., Schaal, S.F. (1991).
- The autonomic and hemodynamic effects of
oral theophylline in patients
- with vasodepressor syncope. Archives of
Internal Medicine, 151(12),
- :2425-2429. PubMed
- 21. North American Society of Pacing and
Electrophysiology. (1999). Other
- tests: tilt table test. Retrieved June 17,
2003, from NASPE Heart Rhythm
- Society. No longer available.
- 22. Pachon M. J. C., Pachon, M. E. I.,
Pachon, M. J. C., Lobo, T. J., Pachon,
- M. Z., Vargas, R. N. & Jatene, A. D.
(2005). "Cardioneuroablation" -
- new treatment for neurocardiogenic syncope,
functional AV block and
- sinus dysfunction using catheter
RF-ablation. Europace. 7(1), 1-13.
- 23. Raviele, A., Themistoclakis, S. &
Gasparini. G. (1996). Drug treatment of
- vasovagal syncope. In J. J. Blanc and D.
Benditt (Eds.), Neurally
- mediated syncope: pathophysiology,
investigations, and treatment
- (pp. 113-117). Armonk, NY: Futura Publishing
- 24. Reybrouck, T., Heidbuchel, H., Van De
Werf, F., Ector, H. (2002).
- Long-term follow-up results of tilt training
therapy in patients with recurrent
- neurocardiogenic syncope. Pacing &
Clinical Electrophysiology, 25(10),
- 1441-1446. PubMed
- 25. Ruiz, G. A., Calvar, C., Hermes, R.,
Rivadeneira, D., Bengolea, V., Chirife,
- R., Tentori, M. C., & Gelpi, R. J.
(2003). Insulin sensitivity in young
- women with vasovagal syncope. American Heart
- 834-840. PubMed
- 26. Shah, J. S., Gupta, A. K. &
Lokhandwala, Y. Y. (2003). Neurally
- syncope: an overview and approach. Journal
of the Association of
- Physicians of India. 51, 805-810.
- 27. Shneerson, J. M. (2000). Handbook of
sleep medicine. Oxford: Blackwell
- 28. Zeng, C., Zhu, Z., Liu, G., Hu, W.,
Wang, X., Yang, C., Wang, H., He, D.,
- & Tan, J. (1998). Randomized,
double-blind, placebo-controlled trial of
- enalapril in patients with neurally mediated
syncope. American Heart
- Jounal, 136(5), 852-858. PubMed