This document provides guidelines for the evaluation and management of patients with syncope. It discusses the definition and types of syncope, including reflex-mediated syncope and cardiac syncope. The evaluation involves a focused history and physical exam, ECG, cardiac monitoring, echocardiogram, and tilt table testing depending on risk factors. Treatment depends on the underlying cause but may include medications, pacemakers, ablation, or lifestyle changes. Gaps in evidence are also noted.

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2017 ACC/AHA/HRS
Guideline for the
Evaluation and
Management of
Patients With
Syncope
DR DANG QUY DUC
CARDIOLOGY DEPARMENT
CHO RAY HOSPITAL
CHF SYM 030 26-12-2017

2. Canada
 Canadian Cardiovascular Society (CCS) and Canadian Pediatric Cardiology Association (CPCA): Society position statement on the approach
to syncope in the pediatric patient (2017)
 Choosing Wisely Canada: Don't order CT head scans in adult patients with simple syncope in the absence of high-risk predictors (2016)
 Choosing Wisely Canada: Don't routinely obtain neuro-imaging studies (CT, MRI scans, or carotid Doppler ultrasonography) in the
evaluation of simple syncope in patients with a normal neurological examination (2015)
 CCS: Society position statement – Standardized approaches to the investigation of syncope (2011)
United States
 American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Rhythm Society (HRS): Guideline for the evaluation and
management of patients with syncope (2017)
 Choosing Wisely: Avoid CT of the head in asymptomatic adult patients in the emergency department with syncope, insignificant trauma
and a normal neurological evaluation (2014)
 Choosing Wisely: Don't perform imaging of the carotid arteries for simple syncope without other neurologic symptoms (2013)
 Choosing Wisely: In the evaluation of simple syncope and a normal neurological examination, don't obtain brain imaging studies (CT or
MRI) (2012)
 American College of Emergency Physicians (ACEP): Clinical policy – Critical issues in the evaluation and management of adult patients
presenting to the emergency department with syncope (2007)
 AHA/American College of Cardiology Foundation (ACCF): Scientific statement on the evaluation of syncope (2006)
Europe
 European Society of Cardiology (ESC): Guidelines for the diagnosis and management of syncope (2009)
United Kingdom
 National Institute for Health and Care Excellence (NICE): Clinical guideline – Transient loss of consciousness ("blackouts") in over 16s
(2010, updated 2014)
 NICE: Quality standard – Transient loss of consciousness ("blackouts") in over 16s (2014)
Japan
 Japanese Circulation Society (JCS): Guidelines for diagnosis and management of syncope (2011, revised 2012)

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Contents
GENERAL PRINCIPLES1
EVALUATION AND DIAGNOSIS2
TREATMENT3
EVIDENCE GAPS4

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1-3% ED visits and hospital admissions in
USA.
Prevalence rates: 41%, with recurrent
syncope 13.5%.
Minnesota (USA): Prevalence 19%;
Females: (22% versus 15%;p<0.001).
Older patients: 7% annual incidence
of syncope, 30% 2- year recurrence rate.

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SYNCOPE
1. A symptom:
 with an abrupt, transient, complete loss of
consciousness,
 inability to maintain postural tone,
 rapid and spontaneous recovery.
2. Seizure, head trauma.
3. Mechanism: cerebral hypoperfusion.

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Loss of consciousness
A cognitive state:
lacks awareness of oneself and one’s
situation,
inability to respond to stimuli.

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Transient loss of consciousness
Self-limited loss of consciousness
Mechanism: cerebral hypoperfusion

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Cardiac syncope
bradycardia, tachycardia, or hypotension.
low cardiac index, blood flow obstruction,
vasodilatation, or acute vascular
dissection

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OTHER SYNCOPE
Reflex syncope Orthostatic hypotension Postural orthostatic
tachycardia syndrome
a reflex that causes
vasodilation,
bradycardia, or both
A drop in systolic BP of ≥
20 mm Hg or diastolic BP
of ≥ 10 mm Hg with
assumption of an upright
posture
an increase in heart rate of
≥ 30 bpm during a
positional change from
supine to standing (or ≥ 40
bpm in those 12–19
1. Vasovagal
syncope.
2. Carotid sinus
syndrome.
3. Situational
syncope

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Uncommon syncope

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Uncommon syncope

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Uncommon syncope

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Uncommon syncope

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Uncommon syncope

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Uncommon syncope

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EVALUATION

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EVALUATION

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EVALUATION
Cardiac Arrhythmic
Conditions
Cardiac or Vascular
Nonarrhythmic
Conditions
Noncardiac Conditions
1. Sustained or
symptomatic VT
2. Symptomatic conduction
system disease or
Mobitz II or third-degree
heart block
3. Symptomatic
bradycardia or sinus
pauses not related to
neurally mediated
syncope
4. Symptomatic SVT
5. Pacemaker/ICD
malfunction
6. Inheritable
cardiovascular
conditions predisposing
to arrhythmias
1. Cardiac ischemia
2. Severe aortic stenosis
3. Cardiac tamponade
4. HCM
5. Severe prosthetic valve
dysfunction
6. Pulmonary embolism
7. Aortic dissection
8. Acute HF
9. Moderate-to-severe LV
dysfunction.
1. Severe
anemia/gastrointestinal
bleeding
2. Major traumatic injury
due to syncope
3. Persistent vital sign
abnormalities

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EVALUATION

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Blood Testing

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Autonomic Evaluation
 Central or peripheral autonomic nervous
system damage or dysfunction.
 Weakness, fatigue,visual blurring,
cognitive slowing, leg buckling, the “coat
hanger” headache → provoked or
exacerbated by exertion, prolonged
standing, meals, or increased ambient
temperature.

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Autonomic Evaluation
 Central autonomic disorders:
 multiple system atrophy,
 Parkinson’s disease,
 Lewy Body dementia.
 Peripheral autonomic dysfunction:
 pure autonomic failure,
 neuropathies due to diabetes amyloidosis,
 immune-mediated neuropathies,
 hereditary sensory and autonomic neuropathies,
 inflammatory neuropathies,
 vitamin B12 deficiency, neurotoxic exposure, HIV and other
infections, and porphyria.

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Orthostatic hypotension

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POTS
1) Symptoms occur standing
(lightheadedness, palpitations,
tremulousness, generalized weakness,
blurred vision, exercise intolerance, and
fatigue)
2) an increase in heart rate of > 30 bpm
during a positional change from supine to
standing (or > 40 bpm in those 12–19)
3) the absence of OH.
Postural orthostatic tachycardia syndrome

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POTS
2015 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Treatment of POTs

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Neurological Diagnostics
EEG, CT, MRI, and carotid ultrasound.
 very limited value in the context of syncope
evaluation and management,
 the diagnostic yield is low,
 very high cost per diagnosis.
not recommended in the routine valuation
of patients with syncope in the absence of
focal neurological findings.

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Reflex evaluation
Vasovagal
syncope
Carotid Sinus
Syndrome
Situational
syncope
hypotension and/or bradycardia
Prolonged
standing or
exposure to
emotional
stress, pain,
or medical
procedures
a pause > 3 s
and/or a decrease of
systolic pressure >
50 mm Hg occurs
upon stimulation of
the carotid sinus
coughing,
laughing,
swallowing,
micturition, or
defecation

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Reflex evaluation

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Pseudosyncope
1. young females
2. history of physical and/or sexual abuse.
3. loss of consciousness is often long (5 to
20 minutes), and episodes are frequent.
4. other characteristics: closed eyes, lack of
pallor and diaphoresis, and usually little
physical harm.
5. normal pulse, blood pressure, or EEG
during pseudosyncope.

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CARDIACVASCULAR
SYNCOPE
Arrhythmic Conditions
Bradycardia
Supraventricular Tachycardia
VentricularArrhythmia
Structural Conditions
Ischemic and Nonischemic
Cardiomyopathy
Valvular Heart Disease
Hypertrophic Cardiomyopathy
Arrhythmogenic Right Ventricular Cardiomyopathy
Cardiac Sarcoidosis
Inheritable Arrhythmic Conditions
Brugada Syndrome
Short-long QT Syndrom
Catecholaminergic Polymorphic Ventricular Tachycardia
Early Repolarization Syndrom

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Adult Congenital Heart
Disease
referral to a specialist with expertise in
ACHD can be beneficial.
EPs is reasonable in patients with
moderate or severe ACHD and
unexplained syncope.

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Athletes
Cardiovascular assessment
Assessment by a specialist with disease-
specific expertise
Extended monitoring
Not recommended for athletes with
syncope and phenotype-positive HCM,
CPVT, LQTS1, or ARVC.

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DRIVING

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