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IT’S ENOUGH TO MAKE YOU FAINT
POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME
Evelyn Wiener, MD
University of Pennsylvania
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SH
SEMESTER
Fall 2008
Freshman, completed four courses.
Spring 2009
Four courses. Completed none.
Summer 2009
Requested leave of absence.
Fall 2009
Requested return from leave.
Fall 2010
Requested return from leave, with accommodations.
Spring 2011
Three courses. Completed two.
Fall 2011
Four courses, completed all four.
Spring 2012
Four courses, completed all four.
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OBJECTIVES
• Explain physiologic response to changes in
posture
• List proposed causes of postural orthostatic
tachycardia syndrome (POTS)
• Describe clinical features of POTS
• Discuss management
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WHY DON’T WE FALL OVER
WHEN WE STAND UP??
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Parasympathetic
nervous system
Sympathetic nervous system
α
β
Heart rate
↓
↑
Contractility
↓
↑
Arterial system
Constricts
Venous system
Constricts
Dilates
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BARORECEPTORS ARE THE KEY
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WHAT COULD GO WRONG?
• Lack of fuel
– Decreased intravascular volume
• Mechanical failure
– Decreased cardiac output
• Failure to respond appropriately
– Neurogenic causes
– Orthostatic failure/intolerance
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NEUROGENIC SYNCOPE
• Inhibition of vascular sympathetic tone
• Neurogenic vasodepressor reactions
– Vasodepressor (vasovagal) syncope
– Neurocardiogenic syncope
– Carotid sinus hypersensitivity
– Severe pain
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NORMAL
PHYSIOLOGY
“VASOVAGAL”
SYNCOPE
POTS
Venous return
↓
↓
↓
Stroke volume
↓
↓
↓
Pulse pressure
↓
↓
↓
Sympathetic tone
↑
Vagal tone
↓
↑
Heart rate
↑
(10 – 15 bpm)
↓
↑↑↑
(>30 bpm)
Systolic pressure
Stable
↓↓
↓
Diastolic pressure
↑
(~10 mm)
↓
↓
↑↑↑
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PATHOGENESIS
?
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PROPOSED ETIOLOGIES
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Distal denervation
Hypovolemia
Changes in venous function
Baroreflex abnormalities
Increased sympathetic activity
Genetic abnormalities
Immune mediated
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CLINICAL FEATURES
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CEREBRAL HYPOPERFUSION
AUTONOMIC OVERACTIVITY
DYSAUTONOMIA
SUDOMOTOR SYMPTOMS
GENERALIZED COMPLAINTS
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Grading of Orthostatic Intolerance
GRADE 0
Normal orthostatic tolerance
GRADE I
Orthostatic symptoms infrequent or occur only under increased orthostatic
stress
Patient can stand > 15 minutes most occasions
ADL typically unrestricted
GRADE II
Orthostatic symptoms frequent (weekly or more often) and commonly
develop with orthostatic stress
Patient can stand > 5 minutes on most occasions
Typically some limitation in ADL
GRADE III
Orthostatic symptoms develop on most occasions and are regularly
unmasked by orthostatic stresses
Patient can stand > 1 minute on most occasions
Patient is seriously incapacitated (bed- or wheelchair-bound)
Syncope/presyncope common
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Indications for head-up title-table testing
1. Unexplained recurrent syncope or single syncopal episode associated with injury
(or significant risk of injury) in absence of organic heart disease
2. Unexplained recurrent syncopal episodes or single syncopal episode associated
with injury (or significant risk of injury) in setting of organic heart disease after
exclusion of potential cardiac cause of syncope
3. After identification of a cause of recurrent syncope in situations in which
determination of an increased predisposition to neurocardiogenic syncope could
alter treatment
Conditions in which tilt-table testing may be useful
1. Differentiating conclusive syncope from epilepsy
2. Evaluation of recurrent near syncope or dizziness
3. Evaluation of syncope in autonomic failure syndromes
4. Exercise- or postexercise-induced syncope in absence of organic heart disease in
whom exercise stress testing
cannot reproduce an episode
5. Evaluation of recurrent unexplained falls
Hurst's The Heart21
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DIAGNOSTIC CRITERIA
1. Heart rate increase of > 30 beats/min within 10
minutes upright tilt or
2. Heart rate > 120 beats/min within 10 minutes
upright tilt
3. Consistent symptoms of orthostatic intolerance
4. Absence of a known cause of autonomic
neuropathy
5. Serum norepinephrine > 600 pg/mL
(hyperadrenergic form)
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DIFFERENTIAL DIAGNOSIS
• Conditions causing/exacerbating orthostatic
intolerance
• Medications
• Autonomic orthostatic hypotension
• Inappropriate sinus tachycardia
• Chronic fatigue
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NON-PHARMACOLOGIC MANAGEMENT
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Changing eating habits, diet
Changing schedule
Measures to lessen venous pooling
Physical maneuvers, tilt training
Avoid exacerbating activities/factors
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PHARMACOLOGIC MANAGEMENT
• No medication currently approved by FDA:
ALL MEDICATIONS ARE OFF-LABEL
• Increase intravascular volume
• Vasoconstrictors
• Block increased heart rate
• Treatment for autonomic disorder
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RESTRICTIONS?
ACCOMMODATIONS?
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When/how to “protect” student at risk
Living arrangements
Snacks
Excused absence
Extra time
Driving
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ACKNOWLEDGEMENTS
• Dawn Marsh RN (Adrian College)
• Laura Champion, MD (Calvin College)
• Dina M. Oleksiak,MSN,CRNP (La Salle University)
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