Neurocardiogenic syncope
BMJ 2004; 329 doi: https://doi.org/10.1136/bmj.329.7461.336 (Published 05 August 2004) Cite this as: BMJ 2004;329:336
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In addition to Chen-Scarabelli and Scarabelli's list of helps for
syncope can I add that compression stockings are a reliable way to avoid
theatre faints. Some seem to cope with knee length but for the more prone
amoung us or for long procedures thigh length work well.
Competing interests:
None declared
Competing interests: No competing interests
Why must there be a dichotomy between symptoms and signs? Some
manifestations of disease are both subjectively described by patients and
objectively verifiable by their physician. Rigors are suffered by the
patient and observed by the carer - is that a symptom or sign? Since in
many circumstances syncope is described by the patient but not witnessed
by the physician perhaps symptom is more accurate - but does it really
matter?
Competing interests:
None declared
Competing interests: No competing interests
EDITOR – the excellent review of neurocardiogenic syncope describes
the commoner causes; vasovagal syncope, carotid sinus syncope, and
situational syncope. Glossopharyngeal neuralgia (GN) syncope was also
mentioned but no treatment was described. Approximately 10% of patients
with GN experience sudden excessive vagal outflow during an attack which
can result in bradycardia, hypotension, syncope, or even a seizure or
cardiac arrest1. For this reason use of the term vago-glossopharyngeal
neuralgia has been proposed2.
Microneurosurgery is effective in curing not only the pain but also
the syncope in these cases. Via a keyhole craniotomy behind the mastoid,
the glossopharyngeal and vagal rootlets can be easily approached. In many
cases the syndrome is caused by vascular compression which can be
corrected with a technique known as microvascular decompression in which
the offending vessel is repositioned3. In the absence of vascular
compression equally effective result is achieved by dividing the
glossopharyngeal nerve and also the uppermost two vagal rootlets4.
Because the condition is rare it is often not considered in the
differential diagnosis of cardiogenic syncope. We have studied two cases
of vago-glossopharyngeal neuralgia both of which were thought to be
from two unrelated conditions, a heart problem and facial pain.
“The penny did not drop” until a neurosurgical opinion was requested. The
first case has been cured by nerve root section, which surprisingly causes
no neurological deficit in the majority of cases.
Any patient with paroxysmal facial pain and syncope should be
considered for this benign neurosurgical procedure which can be successful
in up to 98% of cases5.
1 Thomson JL. Glossopharyngeal neuralgia accompanied by
unconsciousness.
J Neurosurg 1954 11: 511-515.
2 White J, Sweet WH. A 40 year experience: Pain and the
neurosurgeon.
Springfield IL, Charles C Thomas, 1969, pp 265-302.
3 Resnick DK, Jannetta PJ, Bissonnette D et al. Microvascular
decompression for glossopharyngeal neuralgia. Neurosurgery 1995 36: 64-
69.
4 Taha JM, Tew JM. Long term results of surgical treatment of
idiopathic neuralgias of the glossopharyngeal and vagal nerves.
Neurosurgery 1995 36: 926-931.
5 Sampson JH, Grossi PM, Asaoka K, Fukushima T. Microvascular
decompression for glossopharyngeal neuralgia: Long term effectiveness and
complication avoidance. Neurosurgery 2004 54: 884-890.
Hugh B Coakham Professor
Alex Davies Medical Student
Department of Neurological Surgery,
Institute of Clinical Neuroscience,
Frenchay Hospital,
Bristol
BS16 1LE
Competing interests:
None declared
Competing interests: No competing interests
Dr Fitzpatrick already stressed the importance of distinguishing
between transient loss of consciousness (TLOC) and syncope as a specific
form of TLOC. Part of the differences in opinion no doubt stem from the
lack of a terminological system common to cardiologists, neurologists and
others seeing patients with TLOC. Drs. Chen-Scarabelli and Scarabelli
cannot be faulted for not using the term 'TLOC', as proposals to use this
term for this specific purpose have not yet been published widely. But
everyone will probably agree that it is necessary to distinguish between
groups A and B in the following classification: group A concerns all
disorders that have a transient, self-limited and short-lived loss of
consciousness not due to head trauma in common. This group may be divided
in subgroups according to the cause of the attack. One large subgroup is
due to cerebral hypoperfusion (group B), and another important subgroup
concerns several forms of epilepsy.
Drs Chen-Scarabelli and Chen provide the following definition of
syncope: 'Syncope is defined as a transient loss of consciousness, with
loss of posture (that is, falling).' (1) They cite the ESC definition of
syncope as follows: 'Syncope is indeed defined by the European Society of
Cardiology as “a symptom, defined as a transient, self-limited loss of
consciousness, usually leading to falling.” ' Both their own definition
and their interpretation of the ESC definition conform to group A as
defined above. It is therefore no wonder that they count 'seizure
disorders' (epilepsy), the subclavian steal syndrome and cardiac
arrhythmia among the causes of syncope (see their box 1). While this is a
logical consequence of their concept of syncope, I doubt its wisdom, as
most physicians probably do not wish to classify a tonic-clonic
generalised epileptic seizure as 'syncope'.
Drs Chen-Scarabelli and Scarabelli may be felt to have as much right
to come up with a definition of syncope as the ESC Task Force on syncope.
The term should then be used consistently, and it is not. Some of the
stated causes of 'syncope' (box 1) are not normally associated with loss
of consciousness. TIA's are almost always characterised by neurological
deficit without loss of consciousness. Psychiatric disorders do not
directly lead to loss of consciousness: several conditions may cause
pseudo-unconsciousness (which by any definition cannot be syncope), while
true unconsciousness in psychiatric disorders only occurs indirectly, such
as through drug-induced orthostatic hypotension.
Furthermore, the ESC definition of syncope should be quoted
correctly, meaning in full. The complete version reads: 'Syncope ... is a
symptom, defined as a transient, self-limited loss of consciousness,
usually leading to falling. The onset of syncope is relatively rapid, and
the subsequent recovery is spontaneous, complete, and usually prompt. The
underlying mechanism is a transient global cerebral hypoperfusion.' (2) In
other words, the ESC definition of syncope is completely restricted to
group B! This definition cannot therefore be quoted in defence of Chen-
Scarabelli and Scarabelli's concept of syncope.
The two concepts differ fundamentally. As a co-author of the ESC
paper I am prejudiced in its favour. I expect that the ESC concept is
closer to the common perception of what the word 'syncope' ought to mean
than Chen-Scarabelli and Scrabelli's interpretation.
1. Carol Chen-Scarabelli and Tiziano M Scarabelli. Neurocardiogenic
syncope BMJ 2004; 329: 336-341
2. Task Force on Syncope, European Society of Cardiology: M. Brignole
(Chairman), P. Alboni, D. Benditt, L. Bergfeldt, J. J. Blanc, P. E. Bloch
Thomsen, J.G. van Dijk, A. Fitzpatrick, S. Hohnloser, J. Janousek, W.
Kapoor, R. A. Kenny, P. Kulakowski, A. Moya, A. Raviele, R. Sutton, G.
Theodorakis and W. Wieling. Guidelines on management (diagnosis and
treatment) of syncope. European Heart Journal 2001; 22: 1256–1306.
Competing interests:
None declared
Competing interests: No competing interests
Dear Colleagues,
I really appreciate your reply , but I am in accordance with you, if you
think that neurocardiogenic syncope is not different from all other
syncopes. There is always a loss of consciousness in the neurocardiogenic
too.
About to be a symptom I think it is a sign because it is not dependent
from the description of the patient, and it is not different from patient
to patient; like high blood pressure (160, 170, 180..) : it is simply a
fact.
Competing interests:
None declared
Competing interests: No competing interests
August 10, 2004
Re: syncope is not synonymous with T-LOC
Dear Dr. Fitzpatrick,
T-LOC may be a term or acronym that is used by the European
Federation of Neurological Societies Working Group, but the use of the
words “transient loss of consciousness” is not restricted to this group.
Syncope is indeed defined by the European Society of Cardiology as “a
symptom, defined as a transient, self-limited loss of consiousness,
usually leading to falling.” 1
Furthermore, the major causes of syncope have been categorized into
five major categories: neurologic; metabolic; psychiatric; mechanical
cardiac disease; and cardiac arrhythmias. 2 In fact, metabolic,
neurocardiogenic, psychogenic, and neurological syncope are recognized
terms by the Heart Rhythm Society, a specialty medical society for
electrophysiology. 3 We agree, and did state in our paper, that cerebral
hypoperfusion is the common theme in the pathophysiology of syncope.
However, we disagree that syncope is necessarily a cardiovascular
disorder. The causes of syncope include non-cardiovascular disorders, as
listed in table 1.1 “Causes of Syncope” in the European Society of
Cardiology Task Force report, and include vascular steal syndromes. 1
The confusion (for both patients and health care providers) in cases of
syncope may lie in the belief of ownership (by the neurological society)
of the term “transient loss of consiousness”, a term which is used by
other specialties, including cardiology.
In addition, “neurally-mediated reflex syncopal syndrome” is the
terminology used by the European Society of Cardiology, which defines
“Neurally-mediated reflex syncopal syndrome as a reflex that, when
triggered, gives rise to vasodilatation and bradycardia, although the
contribution of both to systemic hypotension and cerebral hypoperfusion
may differ considerably.” 1 “Neurocardiogenic syncope’ is a term used by
the Heart Rhythm Society to describe “vasovagal syncope” or “the common
faint.” 3
In regards to the cause of the triggering of the reflex which leads
to vasodilatation and bradycardia, the paper clearly states that the
mechanism is poorly understood, but is believed to involve reflex-mediated
changes in the heart rate or vascular tone, caused in part by activation
of the cardiac c fibres. 4, 5
The paper also clearly states that there is lack of evidence of the
efficacy of beta-blockers in the treatment of neurocardiogenic syncope.
Accordingly, the European Society of Cardiology Task Force on Syncope does
not recommend recommend the use of beta-blockers in this setting. However,
because this drug continues to be commonly prescribed by cardiologists for
the treatment of this disorder, it was important to mention the types of
treatment, including drugs, as well as the strength of recommendation and
the strength of evidence, as outlined in Box 4: treatment protocol in the
paper, and the rationale why these and other drugs are prescribed, despite
the lack of evidence. In fact, the paper summarizes the clinical trials of
drug therapies, and clearly states that most randomized, placebo-
controlled clinical studies to date have failed to show any benefit over
placebo.
Finally, reproducibility of tilt-table testing is estimated to be
between 65%-85%.6
Respectfully yours,
Carol Chen-Scarabelli
Tiziano M. Scarabelli
References:
1. Task Force on Syncope, European Society of Cardiology†: M. Brignole
(Chairman), P. Alboni, D. Benditt, L. Bergfeldt, J. J. Blanc, P. E. Bloch
Thomsen, J. G. van Dijk, A. Fitzpatrick, S. Hohnloser, J. Janousek, W.
Kapoor, R. A. Kenny, P. Kulakowski, A. Moya, A. Raviele, R. Sutton, G.
Theodorakis and W. Wieling. Guidelines on management (diagnosis and
treatment) of syncope* European Heart Journal (2001) 22, 1256–1306.
1. Fogoros RN. Practical Cardiac Diagnosis Series;
Electrophysiological Testing, 3rd edition. 1999. Blackwell Publishing,
Malden, Massachusetts.
2. http://www.hrspatients.org/patients/signs_symptoms/fainting/non-
cardiovascular_syncope.asp (The patient education website for Heart Rhythm
Society, the specialty medical society for electrophysiology.)
3. Kapoor WN. Syncope. N Engl J Med. 2000 Dec 21;343(25):1856-62.
4. Abboud FM. Neurocardiogenic syncope. N Engl J Med. 1993 Apr
15;328(15):1117-20.
5. Benditt DG, Ferguson DW, Grubb BP, Kapoor WN, Kugler J, Lerman BB,
Maloney JD, Raviele A, Ross B, Sutton R, Wolk MJ, Wood DL. Tilt table
testing for assessing syncope. American College of Cardiology. J Am Coll
Cardiol. 1996 Jul;28(1):263-75.
Competing interests:
None declared
Competing interests: No competing interests
August 10, 2004
Re: correct definition of syncope
Dear Dr. Gori,
Thank you for your feedback. However, we disagree with several comments.
Syncope is correctly defined as a transient loss of consciousness (i.e.
the loss of consciousness is temporary). In addition, syncope is uniformly
recognized as a symptom, not as a sign, as you suggest. We refer you to
the European Society of Cardiology Task Force on
Syncope 1 report which distinctly states that syncope is a transient
symptom (see page 2, second paragraph in the "Method" section)and the
definition of syncope as "a transient, ...loss of consciousness, usually
leading to falling."(see page 3, first paragraph in the "Definition"
section.
Carol Chen-Scarabelli
Tiziano M. Scarabelli
1. Task Force on Syncope, European Society of Cardiology†: M.
Brignole (Chairman), P. Alboni, D. Benditt, L. Bergfeldt, J. J. Blanc, P.
E. Bloch Thomsen, J. G. van Dijk, A. Fitzpatrick, S. Hohnloser, J.
Janousek, W. Kapoor, R. A. Kenny, P. Kulakowski, A. Moya, A. Raviele, R.
Sutton, G. Theodorakis and W. Wieling. Guidelines on management (diagnosis
and treatment) of syncope* European Heart Journal (2001) 22, 1256–1306.
Competing interests:
None declared
Competing interests: No competing interests
Dear Dr. Gupta,
Thank you for your comments. You are indeed correct that the European
Society of Cardiology guidelines on syncope 1 specifically mention TIAs as
a cause of “non-syncopal attacks (commonly misdiagnosed as syncope).”
Fogoros identifies TIAs as a cause of syncope from neurologic disorders in
his textbook, Electrophysiologic Testing.2
We agree that there is a distinction between syncope and TIAs and that the
management is very different. Thank you for emphasizing this point.
Sincerely,
Carol Chen-Scarabelli
Tiziano M. Scarabelli
References:
1. Task Force on Syncope, European Society of Cardiology†: M.
Brignole (Chairman), P. Alboni, D. Benditt, L. Bergfeldt, J. J. Blanc, P.
E. Bloch Thomsen, J. G. van Dijk, A. Fitzpatrick, S. Hohnloser, J.
Janousek, W. Kapoor, R. A. Kenny, P. Kulakowski, A. Moya, A. Raviele, R.
Sutton, G. Theodorakis and W. Wieling. Guidelines on management (diagnosis
and treatment) of syncope* European Heart Journal (2001) 22, 1256–1306.
2. Fogoros RN. Practical Cardiac Diagnosis Series;
Electrophysiological Testing, 3rd edition. 1999. Blackwell Publishing,
Malden, Massachusetts.
Competing interests:
None declared
Competing interests: No competing interests
Dear Sir,
The Review article published today in the BMJ (BMJ 2004;329:336-41)
contains a number of significant errors and inaccuracies, many of them
worrying and misleading. It is quiet true to say that the problem of
transient
loss of consciousness is a major public health concern, with a very high
incidence, high health and social costs, poor rates of diagnosis, and high
rates of misdiagnosis. However, the European Federation of Neurological
Societies Working Group on Terminology, uses the term T-LOC, and the
Chairman of that group, Professor Gert van Dijk, from the Netherlands,
sits
on our STARS Medical Advisory Committee, (STARS is a syncope Charity,
www.stars.org.uk). Our multi-disciplinary committee has many aims, but
the
most important of these is to ensure that doctors do not confuse T-LOC
with
syncope. Syncope is “transient loss of consciousness due to transient
global
impairment of cerebral perfusion”. Syncope is not synonymous with T-LOC,
and there is no such thing as neurological syncope, metabolic syncope or
psychiatric syncope. Syncope is a cardiovascular disorder, and all the
causes
of syncope cause transient global impairment of cerebral perfusion,
whether
by profound reflex vasodilatation, by obstruction to flow, or by cardiac
arrhythmia.
The confusion of syncope with T-LOC is disastrous for doctors and
patients
alike. It confuses the underlying causes of T-LOC which should be divided
into dysfunction of the brain, dysfunction of the circulation and
dysfunction
of the psyche. Such is the confusion engendered by the misuse of
terminology, that up to 30% of adults and 40% of children are misdiagnosed
with epilepsy. Many of these can be shown to have a cardiovascular cause
of
T-LOC (1). Furthermore, in the USA, doctors refuse to use the term
epilepsy,
which has pejorative overtones, and insist on using “seizure disorder”.
This
again is very misleading. Many of the “classic” features of epilepsy,
such as
abnormal movements, tongue-biting and incontinence occur quite frequently
in convulsive syncope. In this situation the convulsion is caused by
anoxic
irritation of neurones, secondary to impaired cerebral blood flow.
However,
this is not epilepsy, even though it may appear to be. The underlying
pathophysiology is impairment of blood flow to the brain. Giving such
patients anticonvulsants is a disaster, and may effect over 100,000
patients
in the UK. A further important problem is the use of the terms “neurally-
mediated bradycardia-hypotension syndrome”, “neurally-mediated syncope”,
“neurocardiogenic syncope”. These merely serve to confuse further,
because
epilepsy is neurally-mediated, indeed primarily neurological. Reflex
syncope
is a far better descriptive term. The disturbance is caused by triggering
of a
reflex dilatation of skeletal muscle arterioles, diverting blood away from
the
brain, and vagal activation, causing a variable degree of bradycardia, or
asystole. The result is syncope.
Another problem is the insistence on cardiac receptors as a cause of
triggering of reflex syncope. There is no evidence for this, indeed
patients
who have had orthotopic cardiac transplantation and who’s hearts are
completely denervated have been shown to have reflex syncope (2). The
research group with the greatest experience of cardiac C-fibre receptor
research, at the University of Iowa, have debunked this theory. Because
this
theory persists, many people are treated with b-blockers, in the hope of
“reducing inotropy”. It is no surprise that b-blockers have been shown to
be
useless on any properly conducted clinical trial. The only drug that has
been
shown to be significantly beneficial over and above a placebo is
midodrine.
This is very effective, but is only available in the UK on a named patient
basis,
which is detrimental to patients. It is widely available on the
continent. This
reason for this is simple, drug companies sell vast quantities of drugs
for
lowering blood pressure in the UK, and midodrine raises it, albeit
slightly in
the doses effective for reflex syncope. There is no desire to send out
mixed
marketing messages. However, patients are being denied effective
treatment.
Finally, the true value of tilt-table testing should be made much
clearer.
There is no doubt that it can be useful, but there are important
limitations to
it’s predictive accuracy. It is not very reproducible (3), and even
positive
responses may be very different in terms of timing and degree of
bradycardia.
Patients with a high pre-test likelihood of a positive response have a
much
higher yield than patients with low pre-test likelihood of a positive
response
(4). Adding drug provocation increases the yield but increases the chance
of
false-positive responses. In “all comers” with syncope about 20% have a
positive response, (4), versus 10% in control subjects, (3). The very
best
method of investigating T-LOC is by capturing a spontaneous episode during
recording of electroencephalogram, electrocardiogram and beat-to-beat
blood pressure. This can be done during tilt-testing in suspected
psychogenic T-LOC, and it is very valuable because patients may become
unconscious, but there is no disturbance in any of these parameters, (5).
This could be a Gold Standard. However, we do not have the tools to
monitor
all these physiological signals simultaneously in ambulatory patients, and
they are needed. In the meantime, the implantable ECG loop-recorder,
(ILR),
is of help for long-term, (18 months) ECG monitoring.
1. Zaidi A, Clough P, Cooper P, Scheepers B, Fitzpatrick AP.
Misdiagnosis
of epilepsy: many seizure-like attacks have a cardiovascular cause. J Am
Coll
Cardiol. 2000;36(1):181-4.
2. Fitzpatrick A P Banner N Cheng A Yacoub M Sutton R
Vasovagal
reactions before and after re-innervation in patients with orthotopic
cardiac
transplantation JACC 1993; 21: 1132-1137
3. Fitzpatrick A P Theodorakis G Ahmed R Vardas P Sutton R
Methodology of head-up tilt in the investigation of unexplained syncope
JACC 1991; 17: 125-30
4. Fitzpatrick A P Lee R J Epstein L M Lesh M D Scheinman M
M
Effect of patient characteristics on the yield of prolonged baseline head-
up
tilt-testing and the additive yield of drug provocation HEART
1996;
76: 406-411
5. Zaidi A, Crampton S, Clough P, Fitzpatrick AP, Scheepers B Head
-up
tilting is a useful provocative test for psychogenic non-epileptic
seizures.
Seizure 1999 Sep;8(6):353-5
-
Dr Adam P Fitzpatrick MD FRCP FACC
Consultant Cardiologist
Manchester Heart Centre
Ward 16
MRI
M13 9WL
Tel: -44-161-276-8903
Fax: -44-161-276-8911
And
Manor Lodge Consulting Centre
Mill Lane
Cheadle
Cheshire
SK8 2NT
Tel: -44-161-428-2145
Fax: -44-161-428-6202
adam@maxwellton.me.uk
adam.fitzpatrick@cmmc.nhs.uk
-
www.manchesterheartcentre.org
www.nwrepg.com
Competing interests:
None declared
Competing interests: No competing interests
What is Syncope?
I have followed the discussions on syncope, stemming from the
clinical review "Neurocardiogenic syncope" by Chen-Scarabelli C and
Scarabelli TM (BMJ, 328, 7 August 2004,336-341).
This was a useful review of PubMed articles, particularly emphasizing
the lack of evidence for beta-blocker treatment but the effectiveness of
alpha-agonist treatment (Minodrine) for neurally mediated syncope /
neurocardiogenic syncope / vasovagal syncope, and the effectiveness of
cardiac pacing in these patients where there is predominantly asystole or
bradycardia rather than hypotension.
However it has highlighted the problem of definition. "Transient loss
of consciousness" (TLOC) is a useful term clinically but must be
distinguished from "Syncope".
As a paediatric neurologist I see syncope best defined as a type of
TLOC with a particular neuro-biological signature, which can be visualized
on electroencephalography (EEG) as the "slow-flat-slow" change in
background rhythm. This is not seen in other causes of TLOC such as
epileptic seizures, sleep attacks, basilar migraine, hydrocephalic
attacks, or apparent TLOC as in psychogenic non-epileptic attack disorder.
Neurally mediated, neurocardiogenic, vasovagal, reflex asystolic
syncopies and, vitally, syncopies caused by heart disease with arrhythmias
or anatomical abnormalities, acute blood volume loss from burns or
haemorrhage, anaphylaxis, comprise a sub-set mediated by transient
systemic hypotension and or transient cardiac arrest.
Other important mechanisms can also cause syncopies, including
interruption in cerebral blood flow as in adolescent stretch syncope or
excessive G-force (G-LOC), hypoxia, or upper airway obstruction.
Viewed from this neurological perspective gives a more generally
useful definition of syncope as transient loss of consciousness due to "a
sudden reduction in cerebral perfusion by oxygenated blood, either from a
reduction of cerebral blood flow itself or from a drop in the oxygen
content or a combination of the two" (see Stephenson JBP, Fits and Faints,
Clinics in Developmental Medicine 109, 1990, Mac Keith Press, Oxford, 41-
58).
Competing interests:
None declared
Competing interests: No competing interests