Vasovagal Syncope

Sep 16, 2019 admin THẦN KINH, TIM MẠCH 0

Vasovagal Syncope

Aka: Vasovagal Syncope, Neurocardiogenic Syncope, Reflex Mediated Syncope, Micturition Syncope, Cough Syncope, Tussive Syncope, Situational Syncope

II. Causes

  1. See Syncope
  2. Other Reflex Mediated Syncope causes
    1. Situational Syncope
      1. Urination (Micturition Syncope) or with Defecation
      2. Cough Syncope (Tussive Syncope) or sneezing
      3. Valsalva (brass instrument playing, weight lifting)
      4. Hyperventilation
    2. Carotid Sinus Syncope
    3. Glossopharyngeal neuralgia (uncommon)
      1. Syncope occurs with swallowing, talking, sneezing
    4. Trigeminal Neuralgia

III. Definition: Vasovagal Syncope

  1. Dysautonomic response to upright Posture
  2. Includes
    1. Orthostatic Hypotension
    2. Postural Orthostatic Tachycardia Syndrome (POTS)

IV. Phases

  1. Precipitating event (e.g. stress, prolonged standing)
    1. Prolonged standing
    2. Sitting
    3. Heat
    4. Stress
  2. Prodrome (present in 50% of cases)
    1. Duration: Seconds to minutes
    2. Symptoms
      1. Diaphoresis (most common)
      2. Epigastric Pain
      3. Fatigue
      4. Nausea
      5. Pallor
      6. Dizziness or Vertigo
    3. Palliative
      1. Lying down may prevent loss of consciousness and relieve symptoms
  3. Loss of consciousness
    1. May occur without prodrome in half of cases
    2. Brief Seizure-like activity (Myoclonus) may occur on collapse in 5% of cases
  4. Post-Syncope
    1. Duration: Hours
    2. Symptoms
      1. Confusion
      2. Dizziness or Vertigo
      3. Nausea
      4. Malaise

V. Management: General

  1. General prevention measures
    1. Move to supine position to prevent falls at onset of symptoms
  2. Physical counterpressure methods at start of symptoms
    1. Cross Legs
    2. Squat
    3. Tense lower extremities
  3. Increase volume status
  4. Consider increased dietary salt when appropriate
  5. Adjust medications to lower dose
    1. Alpha Adrenergic Antagonist (Prazosin)
    2. Antianginal nitrates (Nitroglycerin)

VI. Management: Medical

  1. Expected medication course
    1. Continue medication for 1 year then taper off
  2. Indications for medical management (see below)
    1. More than two syncopal episodes
    2. Increasingly recurrent syncopal episodes
    3. Syncope without warning or prodrome
    4. Syncope in high risk occupation
      1. Airplane pilot
      2. Truck driver

VII. Approach Step 1: Assess Hemodynamic response to standing

  1. No Hemodynamic Response
    1. See Step 2 below
  2. Blood Pressure decreases: Orthostatic Hypotension
    1. Criteria
      1. Systolic Blood Pressure decreases more than 20 mmHg
      2. Systolic Blood Pressure <90 mmHg within 3 minutes
    2. Management
      1. See Orthostatic Hypotension for management
      2. Increased salt intake
      3. Consider Fludrocortisone (water and salt retention) in refractory cases
      4. Consider Midodrine (Vasoconstrictor) in refractory cases
  3. Pulse increase: Postural Orthostatic Tachycardia (POTS)
    1. Criteria
      1. Heart Rate increases more than 30 beats per minute
      2. Heart Rate >120 beats per minute
    2. Management
      1. Fludrocortisone (water and salt retention)
      2. Midodrine (Vasoconstrictor)
      3. Beta Blockers

VIII. Approach Step 2: Tilt Test not done (Empiric Therapy)

  1. No Hypertension
    1. See Orthostatic Hypotension
    2. Consider Tilt Test
    3. Consider Fludrocortisone (water and salt retention)
    4. Consider Midodrine (Vasoconstrictor)
  2. Hypertension
    1. First line
      1. Beta Blocker
    2. Second line
      1. Clonidine
      2. Disopyramide
      3. Selective Serotonin Reuptake Inhibitor (SSRI)
        1. Paroxetine (Paxil) 20 mg orally daily
        2. Di Girolamo (1999) J Am Coll Cardiol 33:1227-30 [PubMed]
    3. Third line
      1. Dual Chamber Pacemaker

IX. Approach Step 3: Obtain Tilt Test

  1. Tilt Test Criteria
    1. No concurrent medications
    2. Tilt for 45 minutes at 60 to 70 degrees
  2. Gradual fall in Blood Pressure: Dysautonomic Syncope
    1. Fludrocortisone (water and salt retention)
    2. Midodrine (Vasoconstrictor)
  3. Abrupt fall in Blood Pressure: Vasovagal Syncope
    1. Non-pharmacologic measures are preferred (see above)
    2. Heart Rate increases prior to Blood Pressure drop
      1. Consider Beta Blocker
    3. No change in Heart Rate prior to Hypotension
      1. Previously Fludrocortisone was trialed, but not found effective
    4. Refractory cases
      1. Consider dual chamber Pacemaker

X. References

  1. Bloomfield (1999) Am J Cardiol 84:33Q-9Q [PubMed]
  2. Fenton (2000) Ann Intern Med 133:722 [PubMed]
  3. Kapoor (2000) N Engl J Med 343:1856-62 [PubMed]
  4. Runser (2017) Am Fam Physician 95(3): 303-12 [PubMed]

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