Syncope resident survival guide

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alejandro Lemor, M.D. [2]; Karol Gema Hernandez, M.D. [3]

Syncope Resident Survival Guide Microchapters
Overview
Causes
Classification
FIRE
Complete
Clues
Treatment
Do's
Don'ts

Overview

Syncope is the transient loss of consciousness (LOC) due to cerebral hypoperfusion and it is characterized by a rapid onset, a short duration and a spontaneous complete recovery. It is important to identify the cause of syncope and recognize high risk patients with structural heart disease or abnormal ECG findings. The initial management of syncope depends on the etiology of the syncope which can be either reflex, orthostatic hypotension or cardiovascular.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

Common Causes

Click here for the complete list of causes.

Classification

Syncope is classified based on the pathophysiology of the etiology.[3]

Cardiovascular Syncope

Orthostatic Hypotension

Reflex Syncope

FIRE: Focused Initial Rapid Evaluation

A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention.

Boxes in the red signify that an urgent management is needed.

Abbreviations: CT: Computed tomography; DVT: Deep vein thrombosis; ECG: electrocardiogram; STEMI: ST elevation myocardial infarction

 
 
 
 
 
 
 
 
Identify cardinal findings that increase the pretest probability of syncope

Loss of consciousness(LOC) of:
❑ Short duration,
AND
❑ Rapid onset,
AND
❑ Complete spontaneous recovery[3]
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Differentiate syncope from other common similar presentations without LOC
Vertigo
Lightheadedness
Epilepsy
Hypoglycemia
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Does the patient have any of the findings that require urgent management?
Tachycardia
Hypotension
❑ Severe dyspnea
Hemorrhage
Seizures
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
 
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Immediately order an ECG

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ECG findings
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Normal ECG
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Administer:
Aspirin 162-325 mg
Oxygen (2-4 L/min) if satO2 <90%
Beta blockers (unless contraindicated)
❑ Sublingual nitroglycerin 0.4 mg every 5 min for a total of 3 doses
Do not delay primary angioplasty or fibrinolysis
 
❑ Manage the hypovolemic state
❑ Administer IV normal saline 2 L
❑ Give vasopressors if needed
❑ Determine the location and etiology of the bleeding
 
Suggestive signs and symptoms:
❑ Sudden onset of dyspnea and tachypnea
Tachycardia
Pleuritic chest pain
❑ Symptoms suggestive of DVT
❑ Positive CT pulmonary angiography
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 



Complete Diagnostic Approach

A complete diagnostic approach should be carried out after a focused initial rapid evaluation is conducted and following initiation of any urgent intervention.[3][4]

Abbreviations: AF: atrial fibrillation; ARVC: arrhythmogenic right ventricular cardiomyopathy; BBB: bundle branch block; CAD: coronary artery disease; EEG: electroencephalography; HF: heart failure; MI: myocardial infarction; SCD: sudden cardiac death; SVT: supraventricular tachycardia; TIA: transient ischemic attack; VT: ventricular tachycardia

 
 
 
 
 
 
Characterize the symptoms:

Loss of consciousness (LOC)

❑ Rapid or slow onset
❑ Short or long duration
❑ Spontaneous complete recovery or incomplete recovery

Prodrome

Diaphoresis
Nausea
Lightheadedness
Pallor
❑ Warmth
Blurry vision

Chest pain (suggestive of cardiovascular syncope)
Palpitations
❑ Position prior to LOC

Supine (suggestive of cardiovascular syncope)
Supine to erect posture (suggestive of orthostatic hypotension or reflex syncope)
❑ Prolonged standing (suggestive of reflex syncope)

❑ Activity prior to LOC (suggestive of cardiovascular or reflex syncope)

❑ Driving
❑ Machine operation
❑ Flying
❑ Competitive athletics
❑ Bowel or bladder incontinence (suggestive of reflex syncope)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Inquire about medications that can cause syncope:

Nitrates (decrease preload)
Diuretics
Antiarrhythmic
Alpha blocker
Beta blocker
ACE inhibitors
ARB
Hydralazine
Ethanol
Benzodiazepines
Antipsychotics
Tricyclic antidepressants

Barbiturates
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Obtain a detailed past medical history:

❑ Previous syncope episodes

❑ Time since previous episode
❑ Number of previous episodes

❑ Cardiovascular disease

Arrhythmia
Heart block (LBBB, RBBB)
Valvular heart disease
Heart failure
Hypertrophic cardiomyopathy
Cardiac tumor

❑ Neurological diseases

Parkinson's disease
Diabetic neuropathy

Metabolic disorders (diabetes)

❑ Recent trauma
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Identify possible triggers:

Suggestive of reflex syncope
Emotional stress
❑ Crowded places (agoraphobia)
❑ Warm weather
❑ Prolonged standing
Cough
Micturition
Defecation
Swallowing
❑ Rapid head motion
❑ Placing arms over the head
❑ Shaving

Suggestive of cardiovascular or orthostatic hypotension
Trauma
❑ Change in position
Fatigue
Exertion

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Examine the patient:

Vitals
Heart rate

❑ Irregularly irregular rhythm (suggestive of AF)
Tachycardia (suggestive of orthostatic hypotension, cardiovascular or reflex syncope)
Bradycardia (suggestive of cardiovascular syncope)

Blood pressure

❑ Measure in both arms, while standing and supine
Orthostatic hypotension (Fall in systolic BP ≥ 20 mmHg and/or in diastolic BP of at least≥ 10 mmHg between the supine and sitting BP reading)
Hypertension (suggestive of cardiovascular syncope)

Respiratory rate

Tachypnea (suggestive of reflex syncope)

Respiratory
Rales (suggestive of HF)

Cardiovascular
Palpitations (suggestive of arrhythmia)
Carotid bruits (suggestive of cardiovascular syncope)
Murmurs

Aortic stenosis: crescendo-decrecendo systolic ejection murmur best heard at the upper right sternal border
Pulmonary stenosis: systolic ejection murmur best heard at the left second intercostal space

Heart sounds

❑ Loud P2 (suggestive of pulmonary hypertension)

Neurologic
Focal abnormalities (suggestive of stroke or cerebral mass)

Hemiparesis
Vision loss
Aphasia
Hypertonia

Glasgow coma scale
❑ Signs suggestive of Parkinson's disease:

Tremor
Rigidity
Bradykinesia/Akinesia
Postural instability
❑ Shuffling gait
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Order labs and tests:
EKG (most important initial test)
Myocardial infarction
Tachyarrhythmia
Heart block
Bradyarrhythmia
Long or short QT
Bradyarrhythmia

Electrolytes

Hyponatremia
Hypernatremia
Hypokalemia

Glucose (rule out hypoglycemia)
ABG

Hypoxia
Hypocapnea (suggestive of tachypnea, rule out psychiatric disease)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Order imaging studies:
Echocardiography in case of:
Structural heart disease
Myocardial infarction
Cardiac valve disease

Head CT in case of:

Head trauma
TIA
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confirm diagnosis of syncope
Must have this 3 characteristics:
❑ Short duration, AND
❑ Rapid onset, AND
❑ Complete spontaneous recovery
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Syncope
 
 
 
Non-syncopal LOC
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Known etiology
 
 
Unknown etiology
 
Consider additional tests
Stool guaiac test (rule out GI bleeding)
❑ Blood and urine toxicology tests (rule out intoxication)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Determine the etiology:
Cardiovascular
Arrhythmia
Cardiac ischemia
Structural heart disease

Orthostatic hypotension

Syncope after standing up and documentation of orthostatic hypotension (Class I; Level of Evidence: C)

Reflex

Vasovagal syncope precipitated by emotional distress and associated with typical prodome (Class I; Level of Evidence: C)
❑ Situational syncope during or after specific triggers (Class I; Level of Evidence: C)
 
 
Determine if there are any high risk criteria:
❑ Severe structural heart disease
CAD
❑ Clinical or ECG features suggesting arrhythmic syncope
Syncope during exertion or supine
Palpitations at the time of syncope
❑ Family history of SCD
❑ Non-sustained VT
❑ Conduction abnormalities with QRS >120 ms
Sinus bradycardia
Preexcitation syndrome
Long or short QT
Brugada pattern
ARVC

❑ Important comorbidities

❑ Severe anemia
Electrolyte disturbance
 
Consider alternative diagnoses:


With loss of consciousness

Epilepsy
❑ Inquire about suggestive signs include aura, prolonged confusion, muscle ache
❑ Inquire about past medical history
❑ Perform neurological evaluation (Class I; Level of Evidence: C)
❑ Perform tilt testing (Class IIb; Level of Evidence: C), preferably with concurrent EEG and video monitoring if doubt of mimicking epilepsy
Intoxication
❑ Vertebrobasilar TIA


Without loss of consciousness

Vertigo
❑ Perform the Dix-Hallpike test to diagnose BPPV
Lightheadedness
Cataplexy
Drop attacks
❑ Functional /psychogenic pseudosyncope
❑ Perform a psychiatric evaluation (Class I; Level of Evidence: C)
TIA of carotid origin
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
High risk
 
 
 
 
Low risk
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Immediate in-hospital monitoring (in bed or telemetry) to look for abnormalities suggestive of arrhythmic syncope (Class I; Level of Evidence: B)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Recurrent episodes of syncope
❑ Order a Holter if > 1 episode/week (Class I; Level of Evidence: B)
❑ Order external loop recorder (ELR) if interval between episodes < 4 weeks (Class IIa; Level of Evidence: B)
❑ Perform carotid sinus massage in patients > 40 years with uncertain syncopal etiology (Class I; Level of Evidence: B)
Contraindicated in patients with previous TIA or stroke in the past 3 months
Contraindicated in patients with carotid bruits
 
 
 
 
Single episode of syncope
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
In case of suspicion of structural heart disease:
❑ Order an echocardiography (Class I; Level of Evidence: B)
 
 
 
 
Is any of the following high risk setting present?
❑ Potential risk of physical injury
❑ Occupational implications
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Presence of structural heart disease
 
Absence of structural heart disease
 
Yes
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Treat accordingly
 
 
 
Perform a tilt test (Class I; Level of Evidence: B)
 
 
 
No further investigation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ No findings, OR
Reflex syncope: induction of hypotension or bradycardia with reproduction of syncope (Class I; Level of Evidence: B), OR
Orthostatic hypotension: induction of progressive orthostatic hypotension with or without symptoms (Class I; Level of Evidence: B)
 
 
 
 

Diagnostic Clues

Diagnostic clues for the etiologies of syncope
Cardiovascular syncope Orthostatic hypotension Reflex syncope
Diagnostic criteria

Arrhythmia and cardiac ischemia-related syncope diagnosed by ECG specific findings (Class I; Level of Evidence: C)
❑ Cardiovascular syncope due structural heart disease (Class I; Level of Evidence: C)


Additional findings
❑ Presence of definitive structural hearth disease

Aortic stenosis
Acute myocardial infarction
Hypertrophic cardiomyopathy
Pericardial disease
Cardiac tumors

❑ Family history of unexplained sudden death
❑ Syncope during exertion or supine
❑ Abnormal ECG findings
❑ Sudden onset of palpitations before syncope


Abnormal ECG findings
Mobitz I second degree AV block
Wenckebach2.png
❑ Non-sustained VT
Non-sustained VT.png
❑ Premature QRS complexes
VPC 1.png
Wide QRS(≥ 0.12 s)
❑ Long or short QT intervals
LQTS.png
❑ Early repolarization
Benign early repolarization.jpg
Q waves (myocardial infarction)
Q wave.jpg
❑ Bifascicular block
Bifascicular block ECG.png
Diagnostic criteria

❑ Syncope after standing up and documentation of orthostatic hypotension (Class I; Level of Evidence: C)


Additional findings
❑ Syncope after prolonged standing
❑ New antihypertensive drug or dosage change
❑ Presence of autonomic neuropathy
❑ Prolonged standing
❑ Associated with crowd or hot spaces
Diagnostic criteria

Vasovagal syncope precipitated by emotional distress and is associated with typical prodome (Class I; Level of Evidence: C)
❑ Situational syncope during or after specific triggers (Class I; Level of Evidence: C)
Carotid sinus hypersensitivity if syncope is reproduced in the presence of asystole > 3 sec and/or fall in systolic blood pressure > 50 mmHg (Class I; Level of Evidence: B)


Additional findings
❑ Absence of heart disease
❑ History of recurrent syncope
❑ After unpleasant sight, smell, sound or pain
❑ Associated to nausea or vomit
❑ Prolonged standing
❑ Associated with crowd or hot spaces
❑ Head rotation or pressure to carotid sinus
❑ After exertion
❑ Postprandial


Treatment

Shown below is an algorithm summarizing the therapeutic approach to syncope based on the 2009 ESC Guidelines for the Diagnosis and Management of Syncope[3] and the 2006 AHA/ACCF Scientific Statement on the Evaluation of Syncope.[4]

Abbreviations: AF: Atrial fibrillation; SVT: Supraventricular tachycardia; VT: Ventricular tachycardia; MI: Myocardial infarction; BBB: Bundle branch block.

 
 
 
 
Determine the etiology
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Cardiovascular syncope
 
Reflex Syncope
 
Orthostatic hypotension
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Treat the arrhythmia according to the type

❑ Schedule for cardiac pacing surgery in patients with:

Sinus node disease (Class I; Level of Evidence: C)
Mobitz II AV block or complete AV block (Class I; Level of Evidence: B)
BBB with positive electrophysiological study (Class I; Level of Evidence: B)

❑ Schedule for catheter ablation in patients with:

SVT (Class I; Level of Evidence: C)
VT (Class I; Level of Evidence: C)
In absence of structural hearth disease

❑ Administer antiarrhythmic drug therapy in patients with:

AF (Class IIa; Level of Evidence: C)
❑ Failed catheter ablation (Class I; Level of Evidence: C)

❑ Schedule for implantable cardioverter defibrillator surgery in patients with:

VT with heart disease (Class I; Level of Evidence: B)
❑ Electrophysiological study induced VT with previous MI (Class I; Level of Evidence: B)
VT with inherited cardiomyopathy or channelopathy (Class IIa; Level of Evidence: B)
 
❑ Provide adequate hydration and salt intake (Class I; Level of Evidence: C)
❑ Provide additional therapy if needed:
❑ Administer midodrine 10 mg PO every 8 hours (Class IIa; Level of Evidence: B)

Contraindicated in severe heart disease, acute renal failure, pheochromocytoma, severe hypertension or thyrotoxicosis
OR

❑ Administer fludrocortisone 0.1 mg/day PO (Class IIa; Level of Evidence: C)
❑ Educate patients about isometric physical counterpressure maneuvers (PCM) (Class IIb; Level of Evidence: C)
❑ Position the patient in a head-up tilt sleeping position (>10°) to increase fluid volume (Class IIb; Level of Evidence: C)
 
❑ Explain the diagnosis and provide reassurance (Class I; Level of Evidence: C)
❑ Explain the risk of recurrence and educate regarding avoidance of triggers (Class I; Level of Evidence: C)
❑ Educate patients with prodrome about isometric physical counterpressure maneuvers (PCM) (Class I; Level of Evidence: B):
❑ Hand grip and arm tensing
❑ Leg crossing

❑ Consider cardiac pacing in:

❑ Dominant cardioinhibitory carotid sinus syndrome (Class IIa; Level of Evidence: B)
❑ Recurrent reflex syncope, age >40 years and spontaneous cardioinhibitory response during monitoring (Class IIa; Level of Evidence: B)
 
 

Do's

Don'ts

References

  1. Khoo, C.; Chakrabarti, S.; Arbour, L.; Krahn, AD. (2013). "Recognizing life-threatening causes of syncope". Cardiol Clin. 31 (1): 51–66. doi:10.1016/j.ccl.2012.10.005. PMID 23217687. Unknown parameter |month= ignored (help)
  2. Kapoor, WN. (2000). "Syncope". N Engl J Med. 343 (25): 1856–62. doi:10.1056/NEJM200012213432507. PMID 11117979. Unknown parameter |month= ignored (help)
  3. 3.0 3.1 3.2 3.3 Task Force for the Diagnosis and Management of Syncope. European Society of Cardiology (ESC). European Heart Rhythm Association (EHRA). Heart Failure Association (HFA). Heart Rhythm Society (HRS). Moya A; et al. (2009). "Guidelines for the diagnosis and management of syncope (version 2009)". Eur Heart J. 30 (21): 2631–71. doi:10.1093/eurheartj/ehp298. PMC 3295536. PMID 19713422‎ Check |pmid= value (help).
  4. 4.0 4.1 Strickberger, S. A. (2006). "AHA/ACCF Scientific Statement on the Evaluation of Syncope: From the American Heart Association Councils on Clinical Cardiology, Cardiovascular Nursing, Cardiovascular Disease in the Young, and Stroke, and the Quality of Care and Outcomes Research Interdisciplinary Working Group; and the American College of Cardiology Foundation: In Collaboration With the Heart Rhythm Society: Endorsed by the American Autonomic Society". Circulation. 113 (2): 316–327. doi:10.1161/CIRCULATIONAHA.105.170274. ISSN 0009-7322.


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