Please enable JavaScript.

Coggle requires JavaScript to display documents.

Syncope - Coggle Diagram

- - - - Documented cardiac syncope 6-month mortality exceeds 10%
      - Mechanism: heart unable to provide adequate cardiac output
    - - Aortic stenosis
        
        Consider in elderly
        
        Classic triad: chest pain, dyspnea on exertion, syncope
        
        Produces fixed cardiac output
      - Hypertrophic cardiomyopathy
        
        Stiff noncompliant left ventricle
        
        Diastolic dysfunction
        
        Outflow tract obstruction
        
        Most common cause of sudden cardiac death in young adults
        
        May be first recognized in patients >60 years old
      - Massive acute pulmonary embolism
        
        Obstruction of pulmonary vascular bed
        
        Reduction in cardiac output
      - Acute myocardial infarction
        
        Myocardial dyskinesia reduces cardiac output
      - Other structural etiologies
        
        Valvular heart disease: tricuspid stenosis, mitral stenosis
        
        Cardiomyopathy
        
        Pulmonary hypertension
        
        Congenital heart disease
        
        Myxoma
        
        Pericardial disease
        
        Aortic dissection
        
        Myocardial ischemia
    - - Pathophysiologic characteristics
        
        No absolute high or low heart rate predictably produces syncope
        
        Typically sudden onset without prodromal symptoms
        
        Often occurs in damaged or compromised conduction system
        
        High risk for arrhythmias and sudden death
      - In structurally normal hearts
        
        Primary electrolyte imbalance (e.g. hypomagnesemia causing torsades de pointes)
        
        Familial disorders
        
        Brugada syndrome
        
        Long QT syndrome
        
        Short QT syndrome
        
        Catecholamine-associated polymorphic ventricular tachycardia
      - Bradydysrhythmias
        
        Sinus node disease
        
        Second-degree or third-degree heart block
        
        Stokes-Adams attack
        
        Pacemaker malfunction
      - Tachydysrhythmias
        
        Ventricular tachycardia
        
        Torsades de pointes
        
        Supraventricular tachycardia
        
        Atrial fibrillation or flutter
  - - - Autonomic dysfunction that is reflex-mediated or neurally mediated
      - Inappropriate vasodilation
      - Bradycardia
      - Result of inappropriate vagal or sympathetic tone
      - Incidence actually decreases with age
    - - Slow progressive onset
      - Prodrome
        
        Lightheadedness
        
        Nausea
        
        Pallor
        
        Sweating
        
        Feeling of warmth
      - Triggers
        
        Unexpected or unpleasant sight, sound, or smell
        
        Fear
        
        Severe pain
        
        Emotional distress
        
        Instrumentation
        
        Prolonged standing or kneeling in crowded or warm place
    - - Occurs during or immediately after triggers
      - Cough
      - Micturition
      - Defecation
      - Swallowing
    - - Type of reflex-mediated syncope
      - Carotid sinus hypersensitivity with bradycardia or hypotension
      - Receptors located at carotid bifurcation
      - Autonomic responses
        
        Cardioinhibitory response: asystole >3 seconds (most common)
        
        Vasodepressor response: SBP drop >50 mm Hg without HR change
      - Demographics
        
        More common in men
        
        Elderly
        
        Ischemic heart disease
        
        Hypertension
        
        Head and neck malignancies
      - Diagnosis requirements
        
        Must culminate in syncope or prodrome recurrence
        
        Associated with inciting event (shaving or turning head)
        
        Only ~25% with hypersensitivity have true carotid sinus syndrome
        
        Consider in older patients with recurrent syncope and negative cardiac evaluation
    - - Neuralgia
      - Breath holding in children
  - - - Drop in SBP >=20 mm Hg
      - Or drop in DBP >=10 mm Hg
      - Associated with syncope or presyncope
    - - Gravity shifts blood to lower body upon standing
      - Cardiac output drops
      - Normal compensatory response fails
        
        Failure to increase sympathetic output
        
        Failure to decrease parasympathetic output
      - Neurogenic orthostatic hypotension from ANS dysfunction
      - Onset usually within first 3 minutes of standing
      - Can be delayed in some patients
    - - Positive orthostasis in up to 40% of asymptomatic patients >70 years old
      - Positive orthostasis in ~25% of asymptomatic patients <60 years old
      - Does not always result in syncope
      - Rule out serious life-threatening causes before attributing to orthostasis
    - - Intravascular volume loss
      - Poor vascular tone from alpha-receptor disorders
      - Medications
  - - - Associated with up to 40% of vasovagal syncope
      - Associated with 37% to 62% of unexplained syncope
      - Diagnosis of exclusion after ruling out organic causes
      - Most frequent: generalized anxiety disorder, major depressive disorder
    - - Loss of consciousness without impaired cerebral perfusion
      - Eye closure during event
      - Long periods of apparent transient loss of consciousness
      - Increased heart rate and blood pressure
    - - Associated with panic disorder or generalized anxiety
      - Produces hypocarbia and cerebral vasoconstriction
  - - - Erectile dysfunction drugs
      - Antihypertensives
      - Cardiac glycosides
      - Antidysrhythmics
      - Antipsychotics
      - Antiparkinsonism drugs
      - Antidepressants
      - Phenothiazines
      - Alcohol
      - Cocaine
  - - - Neurologic causes are rare
      - Must be transient with no persistent neurologic deficits
      - Persistent deficits or AMS indicate alternate disorders (stroke, sepsis, overdose)
    - - Vertebrobasilar atherosclerotic disease or basilar artery migraine
      - Decreased blood flow to reticular activating system
      - Preceded by diplopia, vertigo, focal neurologic deficits, or nausea
    - - Narrowing of subclavian artery proximal to vertebral artery origin
      - Narrowing more common on the left
      - Arm exercise shunts blood away from vertebrobasilar system to arm
      - Exam: decreased pulse volume and diminished BP in affected arm
    - - Mechanisms: increased ICP causes decreased cerebral perfusion pressure
      - Usually accompanied by focal deficits, headache, or persistent AMS
      - Syncope from any cause can result in trauma with traumatic SAH
    - - Convulsive syncope: mild brief tonic-clonic activity can occur in syncope
      - Features favoring seizure
        
        Previous history of seizure
        
        Epileptic aura
        
        Witnessed head turning or unusual posture during event
        
        Prolonged postictal confusion lasting more than several minutes
        
        Postictal muscle pain
        
        Tongue biting
      - Features favoring syncope
        
        Characteristic prodrome of nausea and diaphoresis
      - Non-distinguishing feature: urinary incontinence is not useful
- - - - To both cerebral cortices
      - Or to brainstem reticular activating system
- - - - Patient position (supine suggests high risk)
      - Environmental stimuli
      - Strenuous activity or exertion (raises suspicion for cardiac cause)
      - Arm exercise (raises suspicion for subclavian steal)
      - Duration of loss of consciousness
      - Symptoms after regaining consciousness
      - Witness account
    - - Aura
      - Headache (concern for SAH)
      - Diplopia, vertigo, focal weakness (concern for neurologic cause)
      - Chest pain (concern for AMI, dissection, PE, aortic stenosis)
      - Palpitations (concern for dysrhythmia)
      - Shortness of breath (concern for PE, CHF)
      - Abdominal or back pain (concern for leaking AAA, ruptured ectopic)
      - Sudden event without warning (raises suspicion for cardiac cause)
    - - Prior syncope: >5 episodes in 1 year suggests vasovagal or psychiatric
      - Structural heart disease (congenital, valvular, CAD, CHF)
      - Risk for PE and VTE
      - Ventricular dysrhythmias
      - Medications and over-the-counter drugs (laxatives, diet pills)
      - Alcohol or substance abuse
      - Family history of prolonged QT, dysrhythmias, sudden cardiac death
    - - Falls or single-car motor vehicle crashes (driving off road)
      - High suspicion if age >65 years, CAD history, or abnormal ECG
      - Avoid missing syncopal event due to preoccupation with trauma
  - - - Bilateral arm blood pressure (unequal suggests dissection or subclavian steal)
      - Orthostatic blood pressure
        
        Measured after 5 minutes supine
        
        Repeated after 1 and 3 minutes standing
        
        Abnormal: symptomatic SBP drop >20 mm Hg
        
        Abnormal: SBP drop <90 mm Hg independent of symptoms
      - Cardiac auscultation: murmur of hypertrophic cardiomyopathy or aortic stenosis
  - - - Obtain 12-lead ECG and place on cardiac monitor
      - Important for risk stratification despite low diagnostic yield alone
      - Value of ED monitoring is additive to single ECG
      - Concerning findings
        
        Acute ischemia or new ECG changes
        
        Dysrhythmia or non-sinus rhythm (2.5 times higher morbidity)
        
        Heart block
        
        Conduction delays: first-degree AV block or LBBB/fascicular block (3.5 times higher morbidity)
        
        Prolonged QTc interval (>470 ms, with >500 ms associated with significant outcomes)
        
        Short QTc interval (<350 ms)
    - - Not routine; guided by history and physical examination
      - CBC: indicated for orthostasis with heme-positive stool
      - Urine pregnancy test: reproductive-age females
      - Serum electrolytes: rarely determine cause
      - Acid-base status: transitory wide anion gap acidosis follows generalized seizure but absent in syncope
      - Blood urea nitrogen: elevated level predicts serious adverse outcome within 30 days
      - BNP or pro-BNP: level >300 pg/mL indicates risk
    - - Carotid Sinus Massage
        
        Not routinely performed in ED evaluation
        
        Indications: suggestive history of carotid sinus syndrome
        
        Requires continuous ECG and BP monitoring, informed consent
        
        Technique: massage each carotid body separately for 5 to 10 seconds
        
        Positive test: symptom reproduction with asystole >3 s or SBP drop >50 mm Hg
        
        Contraindications: known carotid stenosis, bruits, stroke/MI within 3 months, history of VT/VF
        
        Complication: neurologic deficit >24 hours occurs in ~0.1%
      - Hyperventilation Maneuver
        
        Rate of 20 to 30 breaths/min for 2 to 3 minutes with open mouth
        
        Useful in young patients with undiagnosed syncope and suspected psychiatric cause
        
        Positive test: reproduction of prodrome or syncope
      - Neurologic Testing
        
        CT, EEG, LP have very low yield without trauma or focal deficits
        
        Asymptomatic patients returned to baseline do not warrant CT or MRI
      - Pulmonary Embolism Evaluation
        
        Prevalence in ED syncope ranges from 0.06% to 1.4%
        
        Prevalence in admitted syncope is 0.15% to 2%
        
        Not routine; reserved for patients with VTE risk factors or suggestive features
- - - - C: History of congestive heart failure
      - H: Hematocrit <30% (<0.30)
      - E: Abnormal ECG (non-sinus rhythm, monitoring changes, new conduction/QRS/ST changes)
      - S: Shortness of breath
      - S: Systolic blood pressure <90 mm Hg in ED
      - Performance: any 1 factor yields 89% sensitivity and 52% specificity for death at 1 year
    - - History of CHF
      - Age >45 years
      - History of arrhythmia
      - Abnormal ECG
      - Assessed: arrhythmia or death at 1 year
    - - Abnormal ECG
      - History of cardiac disease
      - Age >65 years
      - Lack of prodrome
      - Assessed: death at 1 year
    - - Abnormal ECG
      - History of CHF
      - Age >65 years
      - Assessed: subsequent arrhythmia
    - - Abnormal ECG
      - History of cardiac disease
      - Lack of prodrome
      - Concomitant trauma
      - Assessed: death or need for major procedure at 10 days and 1 year
    - - Abnormal ECG
      - History of cardiac disease
      - Lack of vasovagal etiology
      - Elevated troponin
      - SBP <90 mm Hg or >180 mm Hg
      - Assessed: death or serious neurologic/cardiac adverse event at 30 days
- - - - Clear reflex-mediated syncope
      - No history of heart disease
      - Currently asymptomatic
      - Normal physical exam and normal ECG
      - Disposition: discharge with nonurgent primary care follow-up
    - - Active chest pain or dyspnea
      - Exertional syncope
      - Sudden palpitations prior to syncope
      - ECG conduction abnormalities or ongoing arrhythmia
      - History of CHF or structural heart disease
      - Family history of sudden cardiac death
      - Disposition: admission to hospital or syncope observation unit
  - - - Indication: admitted patients or outpatient ambulatory monitoring
      - Utility: confirms cardiac syncope if symptoms match dysrhythmia; excludes if symptoms occur in sinus rhythm
    - - Indication: recurrent syncope after admission evaluation
      - Utility: diagnostic yield >50% in recurrent syncope
    - - Indication: suggestive history, exam, or ECG of structural heart disease
      - Utility: confirms and quantifies structural heart disease (uncommon if history, exam, ECG normal)
    - - Indication: documented dysrhythmia, preexcitation, serious underlying heart disease
      - Utility: identifies inducible tachy- and bradydysrhythmias
    - - Indication: exercise-related syncope
      - Utility: identifies exercise-induced dysrhythmias and postexercise syncope
    - - Indication: neurologic signs/symptoms or suspected seizure
      - Utility: identifies cerebrovascular/subclavian disease or underlying seizure disorder
    - - Indication: recurrent syncope when cardiac etiology is excluded
      - Technique: supine to 60 degrees upright for 45 minutes
      - Utility: reproduces symptoms to establish neurocardiogenic syncope (treat refractory cases with pacemaker)
    - - Indication: young patients with frequent syncope and no underlying heart disease
      - Utility: identifies predisposing generalized anxiety or depressive disorders
    - - Indication: prolonged QTc interval
      - Utility: tests for LQTS gene (gene-negative individuals have very little risk of fatal syncope)