Guideline for Management of Transient Loss of Consciousness Due to Syncope

Guideline for Management of Transient Loss of
Consciousness Due to Syncope
for Primary Care Physicians
Purpose: The following document is intended to assist primary care providers in the
initial evaluation and management of patients who present with symptoms of collapse
and transient loss of consciousness (TLOC). Specifically, the document focuses on
identifying patients who have suffered TLOC due to syncope and risk stratifying them for
purposes of immediate care and/or referral for subsequent specialized evaluation.
It is of the utmost importance that clinicians apply the following guidelines to appropriate
patient populations. The guidelines are intended to assist in the initial management of
patients who have suffered a transient loss of consciousness (TLOC) episode. Thus, the
most critical step is to determine whether or not the patient has truly had loss of
consciousness. If the answer to that question is no, these guidelines are not applicable.
This care pathway is not a generalized approach to patients with “dizziness”, “lightheadedness”, or other symptoms not accompanied by a loss of consciousness. As with all
such documents the recommendations are based on current best evidence but they are
neither intended to supplant experienced clinical judgment nor substitute for specialty
consultation when indicated.
General Introduction: Clinically, most episodes of true loss of consciousness also
result in loss of postural tone. Patients who report symptoms that do not result in falling
when standing or slumping when sitting, more likely than not have not had loss of
consciousness and the management of such patients is not addressed in this care pathway.
Syncope while lying flat can occur but is very rare, but very serious when real. If
presented with such a patient, consider other causes of TLOC first (e.g., seizure,
pseudoseizure, pseudosyncope) and refer the patient accordingly (neurology, psychiatry).
Older patients often present with “dizziness” or ”lightheadedness”. These are difficult
problems but are not usually in the realm of syncope. A geriatrics referral may be
When in doubt, call the Syncope / Arrhythmia service at either UMMC-Fairview or
Fairview Southdale for a consultation. When the story sounds like a classical vasovagal
faint, hospitalization and further referral is generally not needed unless symptoms are
recurrent, cause injury, or are impairing home or work life.
1. Transient Loss of Consciousness (TLOC) is a symptom in which loss of
consciousness has occurred (or seems to have occurred), but is brief and resolves
spontaneously. Syncope (fainting) and seizures are the most common causes. TLOC due
to head injury (concussion) or metabolic disturbances (e.g., hypoglycemia) are less
common in most clinical settings. Conditions that mimic TLOC (e.g., pseudo-syncope,
pseudo-seizures, malingering, etc) are even less frequent but often are difficult to confirm
without additional specialty evaluation. It is crucial to distinguish these various causes of
TLOC, as the treatment and prognosis varies widely.
The above diagram again emphasizes the need to eliminate conditions which “mimic”
TLOC. Within the category of non-trauma induced TLOC, syncope is the most common
cause. Syncope can be separated from the other conditions in this category by bearing in
mind the following definition of syncope.
2. Syncope is a subset of TLOC. Syncope is a symptom in which transient loss
of consciousness (T-LOC) occurs as a consequence of a self-limited, relatively brief,
and spontaneously self-terminating period of inadequate cerebral nutrient delivery
(1). The possible causes of syncope are numerous, but a transient fall of systemic
arterial pressure to a level below the minimum needed to sustain cerebral blood
flow is by far the most common. From a mortality perspective, causes of syncope
may be relatively benign (e.g., vasovagal faint) or very concerning (e.g., certain
arrhythmias, myocardial infarction), but all forms of syncope increase risk of
accidents, injury and diminished QOL. A specific cause must be sought in order to
have any real chance of preventing future attacks.
Initial goals:
In evaluating a patient presenting with suspected syncope it is essential to:
1. Attempt to ascertain if the event was true „syncope‟ or some other cause of
TLOC. A careful medical history of the event(s) and eye-witness accounts are the
best tool. Document the history thoroughly. It is understood that it may not be
possible in the acute care setting to confirm whether the collapse was syncope
versus other causes, but a detailed history will ultimately help subsequent
2. Make a „Risk stratification‟ decision regarding need for „In-hospital‟ („Protected‟)
evaluation versus timely „Out-patient assessment. Currently more syncope
patients are hospitalized than is necessary. However, there is as yet no absolute
consensus of opinion on how to make this decision. On the other hand, a number
of simple rules, established by various published studies, favor hospitalization
(Table 1). The main determinants are any of:
a) an acute cardiac event /primary arrhythmia is suspected,
b) the ECG is abnormal in an important way (e.g., acute or old MI, major
conduction system disease, Brugada or Long QT pattern, frequent ventricular
ectopy or runs of VT)
c) substantial physical injury has occurred (e.g., head injury, fractures,
d) syncope during exertion or while lying down
c) no warning of collapse.
3. Determine what, if any, testing is required beyond the initial evaluation. As a rule,
do not order Brain imaging (unless an injury has occurred), EEG, or Carotid
Dopplers if you think that the diagnosis was syncope. These are expensive and
useless tests for this indication.
4. Determine which patients may benefit from referral to a physician with expertise
in the management and evaluation of patients with syncope. The key (but not
only) determining factors are:
a) failure to establish a confident causative diagnosis
b) physical injury has occurred
c) a cardiac cause is suspected (i.e, structural heart disease, primary
cardiac arrhythmia)
d) suspect need for invasive or special testing (e.g., EP test, long-term
ECG monitoring, possible pacemaker or ICD consideration, possible
myocardial ischemia as cause)
5. Long-term risk assessment (Figure 4) This is often best left to the
Syncope/Arrhythmia clinic (Figure 5). Most healthy vasovagal patients are at low
long-term mortality risk, but 30%/year recurrence rates over the next 3-5 years are
common. The risk of injury and adverse life-style impact are important
Syncope Classification:
Figure 2 summarizes the main causes of syncope. The medical history remains the key to
distinguishing among the groups. However, only a carefully taken and detailed history
will suffice.
The majority (approx 60%) of syncope patients have syncope as the result of a neural
reflex-mediated mechanism, and most of those will have Vasovagal syncope (the
„Common Faint‟). Carotid sinus syndrome, cough syncope, post-micturition syncope,
etc., are other forms of neural-reflex syncope. Carotid sinus syndrome is almost
exclusively seen in older (>60 years) individuals.
It is important to identify patients with vasovagal syncope since their prognosis is quite
good. That is not to say that for some of these patients their syncopal condition is not a
significant source of anxiety and morbidity and possible injury, but Sudden Death risk is
minimal. Further, these patients rarely need hospital admission, and most do not need
referral for specialty care unless events are recurrent, causing injury, or impairing
It is of considerably greater importance to identify patients in whom their syncopal event
is a marker of underlying heart disease (e.g., ischemic or non-ischemic cardiomyopathy,
valvular issues, primary arrhythmias). The patients with syncope related to underlying
structural heart disease have a worrisome prognosis, with a 6-month mortality rate of
10%. Thus, it is imperative that these patients be identified quickly and treated
appropriately. Usually hospitalization and EP evaluation is needed.
In the hospital setting, in assisted living/nursing homes, and in a clinic setting in which
there a large numbers of elderly patients, orthostatic hypotension (often iatrogenic) is the
cause of syncope in a significant number of patients. The history must include detailed
description of how the collapse occurred and must also include careful review of drugs
that the patient is taking. While neurological disease (e.g., Parkinsonism, autonomic
failure syndromes) and frailty may contribute to orthostatic faints, it is prescribed drugs
(particularly diuretics, antihypertensives, and antidepressents) that are often the main
Syncope Evaluation:
The initial evaluation of a patient suspected of having syncope should be focused on
establishing that the patient has in fact had syncope, attempting to identify the etiology of
the syncope and determining the immediate and long-term risk posed by the condition.
None of these goals can be accomplished without a structured approach to the initial
Initial Evaluation:
Despite the fact the importance of a detailed history is constantly harped on in medicine,
in the evaluation of syncope it is hard to over stress this point. The vast majority of the
time the diagnosis can be strongly suspected from the history alone. However, given
time constraints in many clinics and Urgent care settings, the history is incomplete.
As in the standard approach to any clinical problem the history is divided between the
history of the present illness and the patient‟s past medical history. In regard to the
collapse event(s) there are several pieces of information that should be obtained both
from the patient and any witnesses.
Patient History:
Under what circumstances did the event occur?
Vasovagal syncope almost never occurs in patients who are supine
Environment – hot, crowded, stressful, anxiety provoking
What was the patient doing at the time? Syncope occurring during exercise is always
concerning and those patients are considered to be at high risk. It is important
to ensure that the event occurred during actual exercise, not during a break or
after exercise.
• Situational syncope, not surprisingly occurs during specific activities:
-Trumpet players, etc
• Did the patient have any warning signs?
-The lack of a prodrome, especially in the elderly, does NOT exclude vasovagal
-Some prodromal symptoms are related to cerebral hypoperfusion and can occur with
any syncopal episode:
Tunnel vision
Shutting stars in the vision
Roaring in the ears, distant voices
Frequent yawning
-In reflex-mediated syncopal syndromes vagally-mediated prodromal symptoms are
Cold sweat
• Where there any associated symptoms?
Palpitations – one should keep in mind patients who have had a vasovagal event
may describe a sensation that their heart was beating very hard, not rapidly.
Patients who describe the onset of rapid palpitations prior to syncope are of
chest pain/chest discomfort
Acute coronary syndromes and infarction are occasionally complicated by
The severe and abrupt pain associated with aortic dissection not
uncommonly leads to syncope.
Pulmonary emboli can result in syncope; those that do are often large and
hemodynamically significant
• Where there any injuries?
Any LOC event can result in injuries and an injury alone does not exclude a
common cause of syncope such as vasovagal syncope. Nevertheless, patients
who have sustained significant injuries, injuries requiring an intervention,
are considered high risk.
• Where there any residual symptoms after the episode?
Patients with vasovagal syncope often report fatigue and a generalize feeling of
being unwell for hours after an episode but a true post-ictal state is not a feature
of syncope.
Unless the event involved a head injury, new focal neurologic findings are not
expected after a syncopal event and should raise concerns about an alternative
Similarly, prolonged confusion, agitation and/or delirium is not typical in a
patient with syncope.
While usual inquired about, urinary incontinence does not help distinguish between
syncope and a seizures. While less common, even fecal incontinence is not unheard of in
patients with syncope.
Finally, patients should be questioned about prior syncopal events and if present, whether
or not those episodes were similar to the current episode being evaluated. Inquiries
regarding prior evaluation and testing may prevent duplication of testing as well.
Witness History:
Witness reports of the event can be invaluable but should be approached with caution.
• Appearance of the patient:
Patients who have had a vasovagal faint are often described as „white as ghost‟,
„white as a sheet‟ etc. The absence of such a description does not preclude the
diagnosis but a description of the patient appearing „blue‟ or other descriptions
suggesting central cyanosis are concerning.
One should be wary of lay descriptions of “seizures”. Patients with syncope may
well have a few clonic jerks and twitches. Over reliance on such reports can
lead to the diagnosis of a seizure disorder in error. Collaborating evidence of a
seizure disorder should always be sought both in the history and physical exam.
Witness often are impressed by a patient‟s eyes “rolling back in their head”. This
tidbit is of no clinical use but there is little or no point in explaining this to the
• Duration:
This is another point to approach with caution. Witness are often very frightened
and tend to grossly over estimate how long a patient is unconscious. Asking
specific questions, “Did you have time to call 911?” etc can be helpful in this
When it does appear the episode was prolong it is useful to ask the witness what
actions they took to help the patient. If they kept the patient propped up in a
chair or on the commode then the episode might well be prolonged. Patients
with reflex-mediated syncope have prompt recovery after they become supine.
If the episode was clearly prolonged and no mitigating circumstances can be
ascertained one should consider other diagnoses.
Past Medical History:
The primary determinate of the patient‟s future risk is whether or not there is underlying
structural heart disease. For that reason the past medical history should focus on the issue.
Also given the frequency with which orthostatic hypotension is related to iatrogenic
causes, a careful drug history should also be obtained. In particular, recent changes in
diuretic or antihypertensive (including beta-blocker) doses are common triggers. Many
older patients have diminished thirst drive, so even seemingly average drug doses can
become problematic.
Family history, specifically any family history of unexplained sudden death in first
degree relatives should also be documented. Look for any suggestion of certain common
inherited disease such as: Parkinsonism, long QT , Brugada, Arrhythmogenic RV
Physical Examination:
It needs to be stressed that in the initial evaluation of the patient with syncope, the
physical exam includes a 12 lead ECG. The ECG is not considered additional testing. An
abnormal ECG is an important part of the risk stratification of these patients (Figure 3).
As with the history, the physical exam focuses on signs of structural heart disease.
Displaced PMI
Significant murmur
Evidence of CHF- edema, elevated JVP, rales
ECG, again the focus is on identifying evidence of structural heart disease or arrhythmic
heart disease.
• Evidence of prior infarction, Q waves
• Evidence of acute infarction or acute coronary syndrome
• Conduction system disease beyond first degree AV block or Type I second degree AV
• The computer interpretation of the QT interval MUST be confirmed (and documented)
by a manual measurement.
• Evidence of other channelopathies- short QT, Brugada
• Evidence of hypertrophic cardiomyopathy
Additional testing:
The use of additional testing modalities depends on what the most likely diagnosis is
thought to be at the end of the history and physical examination. A great of money is
often spent on tests that are NOT USEFUL. As noted previously, amomg the most
common of these are head CT or MRI, EEGs and Carotid Dopplers. In the absence of
focal neurologic signs or significant head trauma there is no reason to order any these
studies. None provide a basis for syncope. Head imaging is only helpful if there is
suspected intracranial injury present as a consequence of a collapse.
In a patient with a single, or rare event, that is classic for vasovagal syncope and who has
a normal exam and a normal ECG, no further testing is needed.
Given the importance of the presence or absence of structural heart disease in the cause
of syncope and as a worrisome prognostic factor, an echocardiogram is frequently
warranted and should be read by a qualified interpreter. Echocardiograms are generally
not needed in young (<35 years) patients with no history of prior heart disease and a
history suggesting a vasovagal faint.
Ambulatory ECG monitoring should be chosen based on a realistic expectation of a
recording actually capturing something useful. Thus, Holter monitors (24 to 72 hours),
while seemingly inexpensive, rarely provide diagnostic information; consequently, it is
usually a waste of resources for evaluation of occasional syncope spells. The likelihood
of even a 7-day ambulatory ECG recording demonstrating an abnormality requiring
intervention in a patient with one syncopal episode is vanishingly small. The same is true
of 30-day event recorders. Such monitor technologies are only helpful in establishing a
rhythm correlation with a symptom. In a patient with a single episode or episodes that
occur years apart a monitor, even a 30 day monitor, is unlikely to be helpful. In patients
with a rare syncope the most cost effective means of establishing a rhythm diagnosis is
with implantation of an insertable loop recorder (ILR). A loop recorder is a very small
pacemaker-like device that does not have leads in the heart but sits subcutaneously and is
not usually visible. The implant scar is very small. An ILR records ECG over a very long
time (up to 3 yeas) period to capture rare events. As a rule, if ambulatory monitoring is
being considered, referral to a syncope/arrhythmia clinic is warranted.
When the diagnostic dilemma persists despite the above evaluation, referral to a
syncope/arrhythmia clinic is recommended. These clinics review the history in great
detail and have ready access to comprehensive Autonomic Nervous System studies
(including Tilt-table testing, biofeedback, etc.), electrophysiological testing (EPS), and
other procedures.
a) Tilt table testing can be a useful tool for confirming the diagnosis of vasovagal
syncope. However, it is rarely needed in patients with a classic history for vasovagal
syncope. A positive test will not change the management of the condition and a negative
test does not exclude the diagnosis. It may however convince the patient that the true
diagnosis has been established
b) Tilt table studies combined with autonomic testing can be useful in patients
with orthostatic hypotension and other forms of autonomic dysfunction including
Postural Orthostatic Tachycardia Syndrome (POTS) and Inappropriate Sinus Tachycardia
(IST). Tilt table studies can also be useful in patients with recurrent syncope despite
therapy or in patients with atypical histories. Finally, in the elderly tilt table studies may
be helpful in teaching a patient to recognize their warning symptoms to allow for
protective measures to be taken.
c) Biofeedback using non-invasive hemodynamic monitoring can be used to teach
patients how to recognize imminent faints and how to use physical counter maneuvers to
abort attacks.
d) EPS is not often needed for syncope assessment, and of course necessitates
referral. These procedures can unmask hard to detect arrhythmias, and if appropriate be
used to cure the problem by ablation (e.g. PSVT, certain VTs), or ameliorate risk by
pacemaker or ICD implantation.
Treatment of syncope patients depends on the causative diagnosis. Often specialty
referral is needed at this stage.
1) Neural reflex faints: The vasovagal faint is most common. A single rare event
requires only education and reassurance and if possible avoidance of triggers (e.g., pain,
prolonged standing, etc). Usually specialty referral is not needed unless events are
recurrent or result in substantial physical injury, or are impairing life/work. Carotid sinus
syndrome, cough syncope, and most other forms of situational syncope can be more
difficult to manage and will often necessitate referral to the syncope/arrhythmia clinic.
2) Orthostatic faints are trouble-some as they tend to occur in older patients who
are at risk of severe physical injury. If drugs are clearly the cause, then further referral is
not necessarily needed. However, if the cause is unknown or is thought to be due to an
underlying neurological condition affecting the autonomic nervous system, then referral
to the syncope/arrhythmia clinic is appropriate. However, strokes, TIAs, carotid bruits,
seizures, and brain tumors are NOT the cause of syncope. Do not waste time / money
testing for these conditions if „syncope‟ is the problem. If these tests are considered, it
would be prudent to request neurological specialty consultation.
3) Structural cardiac and pulmonary disease and /or arrhythmias are important
causes of syncope and may have a worrisome prognosis. If any of these causes are
suspected, the treatment strategy should be left to the syncope / arrhythmia clinic. It is
possible that drug therapy will be needed but other options including ablation,
implantable devices, coronary intervention or valve repair/replacement may become
When to refer and how to refer to Syncope/Arrhythmia Clinic
The review provided above summarizes the key scenarios in which specialty referral is
appropriate. However, whenever there is uncertainty regarding the nature of the problem
or the optimal approach to treatment and follow-up, referral for a one-time opinion or for
subsequent care is always welcome (Figure 5). Please indicate the level of urgency. It
should be possible for most patients to be seen within 72 business-day hours, but urgent
cases will be scheduled earlier if necessary. Your judgment on timing is crucial.
Syncope/Arrhythmia specialty care is available at:
1. University of Minnesota Medical Center-Fairview (Tel 612--------):
Wayne Adkisson MD
David G Benditt MD
LinYee Chen MD
Scott Sakaguchi MD
2. Firview Southdale Hospital (Tel ….._
Demos Iskos MD
Harry Li MD
Quan Pham MD
Selected References
1. Moya, A, Sutton R, Ammirati F, et al The Task Force for the Diagnosis and Management of
Syncope of the European Society of Cardiology (ESC). Guidelines for the diagnosis and
management of syncope (version 2009). European Heart J. 2009; 30: 2631-2671.
2. Brignole M, Benditt DG: Syncope: An Evidenced-based Approach. Springer, Berlin,
3. Benditt DG, Can I. Initial evaluation of 'syncope and collapse': The need for a risk
stratification consensus. J Am Coll Cardiol 2010: 55:722-724