Vasovagal Syncope

1. See Also
   1. Vasodepressor Syncope
2. Causes
   1. See Syncope
3. Definition: Vasovagal Syncope
   1. Dysautonomic response to upright Posture
   2. Includes
      1. Orthostatic Hypotension
      2. Postural Orthostatic Tachycardia Syndrome (POTS)
4. Phases
   1. Precipitating event (e.g. stress, prolonged standing)
   2. Prodrome
      1. Duration: Seconds to minutes
      2. Symptoms
         1. Diaphoresis
         2. Epigastric Pain
         3. Fatigue
         4. Nausea
         5. Dizziness or Vertigo
      3. Palliative
         1. Lying down may prevent loss of consciousness
   3. Loss of consciousness
   4. Post-Syncope
      1. Duration: Hours
      2. Symptoms
         1. Confusion
         2. Dizziness or Vertigo
         3. Nausea
         4. Malaise
5. Management: General
   1. General prevention measures
   2. Increase volume status
   3. Consider increased dietary salt when appropriate
   4. Adjust medications to lower dose
      1. Alpha Adrenergic Antagonist (Prazosin)
      2. Antianginal nitrates (Nitroglycerin)
6. 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
7. 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. Increased salt intake
         2. Fludrocortisone (water and salt retention)
         3. Midodrine (Vasoconstrictor)
   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
8. Approach Step 2: Tilt Test not done (Empiric Therapy)
   1. No Hypertension
      1. Fludrocortisone (water and salt retention)
      2. Midodrine (Vasoconstrictor)
      3. Consider Tilt Test
   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 PO qd
            2. Di Girolamo (1999) J Am Coll Cardiol 33:1227-30
      3. Third line
         1. Pacemaker
9. 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. Heart Rate increases prior to Blood Pressure drop
         1. First Line
            1. Beta Blocker
         2. Second Line
            1. Fludrocortisone (water and salt retention)
            2. Midodrine (Vasoconstrictor)
         3. Third line
            1. Pacemaker
      2. No change in Heart Rate prior to Hypotension
         1. First Line
            1. Fludrocortisone (water and salt retention)
         2. Second Line
            1. Beta Blocker
            2. Midodrine (Vasoconstrictor)
         3. Third line
            1. Pacemaker
10. References
    1. Bloomfield (1999) Am J Cardiol 84:33Q-9Q
    2. Fenton (2000) Ann Intern Med 133:722
    3. Kapoor (2000) N Engl J Med 343:1856-62