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DISABLEMENT MODEL CASE STUDY 

 

45 
Copyright © by Indiana State University                                                                                Clinical Practice in Athletic Training  
All rights reserved. ISSN Online 2577-8188                                                                     Volume 4 – Issue 2 – September 2021 

 
 

Disablement Model Case Study: Running with Postural Orthostatic 
Tachycardia Syndrome 
Jordan Fenney MS, LAT, ATC, CES*†; Wendy Reitz LAT, ATC*; Hayley M. Ericksen PhD, LAT, ATC** 

*Aurora Sports Health, West Bend, WI; **University of Wisconsin-Milwaukee, Milwaukee, WI; †Muscle and Movement Therapy, 
Cedarburg, WI  
  

 
ABSTRACT 
A 17-year-old high school female cross-country runner and 
basketball player presented with syncope following long-
endurance exercise. The syncope episodes started when the 
patient was 13 years old during a basketball game. After 
the first episode, the patient fainted every time she crossed 
the finish line of a cross-country meet. Her symptoms included 
increased heart rate, shortness of breath, and paresthesia in 
her hands and legs during exercise. The patient also 
experienced some dizziness when quickly sitting or standing 
during activities of daily living. The patient was first 
misdiagnosed with exercise induced asthma and prescribed 
a rescue inhaler to take prior to competition races, however 
the syncope episodes persisted. A referral was made to a 
cardiologist who performed the Q sweat response (QSR) and 
tilt table tests. The test results, and clinical symptoms were 
consistent with a diagnosis of Postural Orthostatic 
Tachycardia Syndrome (POTS). Metoprolol was prescribed 
to slow her heart rate and fludrocortisone to increase blood 
volume. The patient took these medications daily and also 
took an extra half-a-tablet of metoprolol before exercising 
in hot conditions. The patient’s syncope following long 
endurance races was managed by a coach who would catch 
the patient after she crossed the finish line, lay her down and 
elevate her legs until she regained consciousness. Once 
consciousness was regained, her heart rate and oxygen were 
monitored using a pulse oximeter. POTS is a unique condition 
that can be managed with strong communication between 
healthcare professionals. Proper management allows for 
continued competition with some modifications made by the 
athlete and close monitoring by the athletic trainer. It is 
important for athletic trainers to be educated on the signs 
and symptoms of POTS and understand that it can affect 
each athlete differently.   
 
Key Phrases 
Diagnostic testing and physical examination: non-
musculoskeletal conditions; interprofessional practice; 
secondary schools patient population 
 
Correspondence 
Dr. Hayley Ericksen, 3409 N. Downer Ave, Milwaukee, WI 
53201. 
E-mail: erickseh@uwm.edu   
Twitter: @hayericksen_atc 
 
Full Citation 
Feeney J, Reitz W, Ericksen HM. Disablement model 
case study: running with postural orthostatic 
tachycardia syndrome. Clin Pract Athl Train. 
2021;4(2): 45-51. 
https://doi.org/10.31622/2021/0004.2.7.     

 
Submitted: October 29, 2020 Accepted: February 9, 2021. 

INTRODUCTION 
 

Postural Orthostatic Tachycardia Syndrome 

(POTS) is an autonomic nervous system  (ANS) 
disorder which can cause symptoms the following 
symptoms: light‐headedness, fatigue, sweating, 
anxiety, heart palpitations, exercise intolerance 
and near syncope when standing.1 POTS is a 
unique condition affecting approximately 
500,000 people in the United States, with 
predominance in young females.2 There are two 
classifications associated with POTS: primary 
POTS and secondary POTS. Primary POTS is 
thought to be idiopathic, occurring on its own 
without association with another disease, whereas 
with secondary POTS symptoms are experienced 
as a results of another disease diagnosis.3 Primary 
POTS can be classified deeper into partial 
dysautonomia and hyperadrengic.3 Proper 
classification of POTS can help with better 
management of the patient’s symptoms. Clinicians 
should conduct a thorough history to determine if 
a patient may be experiencing primary or 
secondary POTS.  

When the ANS is functioning properly, orthostatic 
stability is maintained when moving from supine or 
prone to seated by increasing heart rate by 10 to 
20 beats per minute (bpm).1 The increase in heart 
rate allows the body to maintain blood pressure 
and supply oxygenated blood to the brain and 
other vital organs.1 This orthostatic stability is 
achieved within 60 seconds under normal 
conditions.1 

In a patient diagnosed with POTS, the innervation 
of the veins or the vein’s response to sympathetic 
stimulation is impaired. 1 This dysfunction leads to 

mailto:erickseh@uwm.edu
https://doi.org/10.31622/2021/0004.2.7


Disablement Model Case Study: Running with Postural Orthostatic Tachycardia Syndrome 
 

 

46 
Copyright © by Indiana State University                                                                                Clinical Practice in Athletic Training  
All rights reserved. ISSN Online 2577-8188                                                                     Volume 4 – Issue 2 – September 2021 
 

over-dilation of the blood vessels and venous 
pooling in the legs, thereby reducing venous return 
to the heart, which subsequently reduces the 
arterial flow of oxygenated blood to the brain.1,4 
For approximately 10 minutes after standing, 
someone with POTS will experience a heart rate 
increase of 30 bpm or more resulting in a heart 
rate greater than 120 bpm as the ANS attempts 
to increase cardiac output and blood pressure to 
supply the brain and vital organs with 
oxygenated blood. With the increase in heart 
rate, a decrease in blood pressure can occur. This 
will lead to less blood flow to the brain and result 
in symptoms such as light‐headedness, fatigue, 
sweating, anxiety, palpitations, exercise 
intolerance, and in some cases syncope.1 
Symptoms of POTS can impair a patient’s ability 
to engage in physical activity and activities of 
daily living, and therefore, can greatly affect the 
patient’s overall quality of life.   

PATIENT INFORMATION 

A 17-year-old female cross-country runner and 
basketball player presented with syncope 
following long-endurance exercise. The patient’s 
other symptoms included increased heart rate, 
shortness of breath, and paresthesia in her hands 
and legs during and after exercise. The syncope 
episodes first started during a middle school 
basketball game in 2014, at the age of 13 years 
old. The patient stated that while playing in the 
game, she was running backwards and she 
tripped and fell. When she got back up, she had 
trouble breathing, so she was substituted out of 
the game. Her mother came down from the 
bleachers and as they were walking out of the 
gym, the patient fainted. The patient’s mother took 
her to a primary care physician where the patient 
was first misdiagnosed with exercise induced 
asthma and given a rescue inhaler. The following 
year, at the age of 14, the patient used the 
prescribed rescue inhaler following cross-country 
practices when she continued to experience 
symptoms of increased heart rate, shortness of 

breath, and paresthesia in her hands and legs. The 
inhaler treatment provided no symptom relief. The 
patient returned to her primary care physician 
and was referred to a specialist at a children’s 
hospital where she was then misdiagnosed with a 
"once in a lifetime throat spasm.” The patient 
continued to participate in cross-country, but when 
she had two more syncope episodes during 
practice, the coach and athletic trainer decided 
that she would be unable to continue participation 
without a proper diagnosis. The patient was 
finally referred to a cardiologist who specializes 
in POTS and the correct diagnosis was made in 
2016, two years after her symptoms began.  

Activity and Participation 

Throughout the patient’s high school career, she 
competed in two sports: basketball and cross 
country. The symptoms of her POTS diagnosis 
impacted her participation in practices and 
competition in different ways. Throughout her 
freshman and sophomore year, she had fainting 
spells during all activity until she received a 
proper diagnosis in 2016. With the correct 
diagnosis and medication, most of her symptoms 
were under control; however, one symptom, 
syncope, persisted and continued to plague her at 
the end of each cross-country competition.  She 
was able to finish her race but would faint into the 
arms of her coach at the finish line. The nature of 
a cross-country finish line- an abrupt stop, caused 
a quick drop in the patient’s blood pressure, which 
decreased blood flow to the brain and triggered 
a syncope episode. After which, the patient 
explained that she felt numbness and tingling in 
her hands and feet for about ten minutes before 
her symptoms would improve. During basketball 
practices and games, the patient did not 
experience syncope episodes but did have 
increased heart rate, shortness of breath, and 
paresthesia in hands and feet. When she began 
having these symptoms, she was able to stop 
participating, sit down, and hydrate while slowly 
decreasing her heart rate, thus avoiding a 



Disablement Model Case Study: Running with Postural Orthostatic Tachycardia Syndrome 
 

 

47 
Copyright © by Indiana State University                                                                                Clinical Practice in Athletic Training  
All rights reserved. ISSN Online 2577-8188                                                                     Volume 4 – Issue 2 – September 2021 
 

syncope episode. The patient was able to work 
through and manage her symptoms with proper 
recognition and recovery techniques. The support 
of medications and other modifications to her 
routine also helped her to manage her symptoms 
and allowed her to continue participating in 
physical activity.  

Differential Diagnosis and Evaluation  

The differential diagnosis list for this case 
included: tachycardia syndrome, chronic fatigue 
syndrome, anxiety, asthma, vasovagal syncope, 
orthostatic hypotension, or cardiac arrhythmias. 
The patient was first misdiagnosed with exercise 
induced asthma and treated with a rescue inhaler 
which did not improve her symptoms. The patient 
then saw a cardiologist, whom after evaluating 
her signs and symptoms, performed a series of 
tests to help determine a correct diagnosis. The 
cardiologist was able to rule out chronic fatigue 
syndrome, anxiety and orthostatic hypotension 
based on evaluation of the patient’s signs and 
symptoms. The patient’s EKG results were 
unremarkable, which helped rule out tachycardia 
syndrome and cardiac arrhythmias. The 
cardiologist suspected she may be suffering from 
POTS and ordered several tests to confirm the 
diagnosis. The Q sweat response (QSR) test was 
performed to evaluate the sweat response of the 
sympathetic nervous system. The QSR test uses 
iontophoresis to stimulate the sweat glands to 
release acetylcholine, resulting in and increased 
sweat response.5 The standard testing sites include 
forearm, proximal leg, distal legs, and dorsum of 
the foot.6 The amount of sweat is measured by the 
change in humidity in the sweat capsule from 
baseline to 15 minutes post stimulation.6 In normal 
individuals, the sweat output increases for about 
5 minutes until it reaches an inflection point and 
then slowly decreases. If a patient has a loss of 
sympathetic nerve terminals, the terminals will not 
release as much acetylcholine resulting in 
decreased sweat.5 The results of this patient’s QSR 
test showed a normal volume of sweat on the 

forearm and proximal leg, increased volume on 
the distal leg, and decreased volume of sweat on 
the foot compared to the proximal leg. The 
decreased volume of sweat on the foot compared 
to the proximal leg shows that the patient has a 
sympathetic nervous system abnormality. The 
cardiologist summarized these results to indicate 
abnormal postganglionic sudomotor function 
showing a mild impairment in the autonomic 
nerves, a result that is consistent with a diagnosis 
of POTS.  

The tilt table test measures heart rate and blood 
pressure while the body is in different positions.7 
The test is meant to mimic the sudden change in 
posture resulting in syncope. The test begins with 
a 10-15 minute baseline period of lying in a 
supine position.7 The table is slowly raised to 
seventy degrees while blood pressure and heart 
rate are measured.7 With the tilt table test the 
doctor is looking for two changes, a decrease in 
blood pressure and/or heart rate as the table is 
tilted upright.7 If the patient can lay at seventy 
degrees without symptoms the clinician will 
introduce a sympathetic medication called 
isoproterenol. This patient was tested with a 
sympathetic medication that caused the heart to 
beat stronger and faster. The patient’s results with 
the medication showed an abnormal response to 
seventy degrees head-up tilt, increased heart rate 
during the second ten minutes of upright tilt, and 
variable blood pressure during upright tilt 
compared to supine baseline. Her tilt table test 
showed that she has hyperadrenergic POTS 
because her results varied after the sympathetic 
drug was introduced. The cardiologist’s summary 
of these findings stated that the patient had 
normal cardiovagal function, but she was 
abnormal when the medication was introduced. 
This is consistent with the fact that she only 
experienced syncope episodes when under stress 
such as long-endurance events.  

Body Structure and Function 



Disablement Model Case Study: Running with Postural Orthostatic Tachycardia Syndrome 
 

 

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Copyright © by Indiana State University                                                                                Clinical Practice in Athletic Training  
All rights reserved. ISSN Online 2577-8188                                                                     Volume 4 – Issue 2 – September 2021 
 

POTS affects the ANS, which is the reflexive and 
involuntary division of the central nervous system.8 
It is responsible for conducting nerve impulses from 
the central nervous system to cardiac muscle, 
smooth muscle, and glands.8 The basic functions of 
the ANS include regulation of one’s heart rate and 
contraction of smooth muscle in the digestive 
tract.8 POTS causes an exaggerated sympathetic 
response when changing orthostatic positioning.  

Environmental and Personal Factors 

Additional factors that may exacerbate the 
symptoms of POTS include, decreased fluid 
intake, dehydration, exercise, morning hours, 
fever and high ambient temperatures.7 Prior to 
running in hot conditions, the patient would take 
an extra dose of Metoprolol. In extreme heat, the 
sympathetic nervous system dilates the blood 
vessels, which brings the blood closer to the skin’s 
surface and heat is lost through radiation from the 
body’s surface. The body also reacts to heat by 
sending a signal, via the sympathetic nerves, to the 
sweat glands in the skin and then heat is lost by 
sweat evaporation.9 One of the main symptoms of 
POTS includes increased heart rate so the extra 
half-a-tablet  of Metoprolol was needed to 
decrease the patient’s heart rate when exercising 
in hot conditions. Metoprolol is a beta-1 
adrenergic receptor blocker which decreases 
one’s heart rate by decreasing the force of 
contraction in the heart.10 This allows the blood to 
flow easier, preventing tachycardia. When 
exercising in hot conditions, sweating and 
tachycardia is exacerbated warranting the need 
for an extra half-a-tablet of metoprolol for this 
patient. 

The patient came from a healthy, supportive 
family who encouraged her to do what she loves. 
In the patient’s mind, quitting was not an option 
and she was willing to do what it took to compete 
while staying healthy. The patient was diligent in 
taking her medications and performing 
modifications if needed. The communication 

between physician, athlete, parents, and the 
athletic trainer was strong, which helped the 
patient to manage her conditions while still 
participating in her sport.  

INTERVENTIONS 
 
Upon being accurately diagnosed with POTS, the 
patient was prescribed Metoprolol to aid in 
slowing her heart rate and fludrocortisone to 
increase blood volume. The patient was 
asymptomatic at rest and during daily activities. 
During and after exercise is when the patient’s 
symptoms become problematic. It was 
recommended that she prolong her cross-country 
race finish to slowly decrease her heart rate 
without a sudden drop in blood pressure. Due to 
the nature of a cross country race, the athletes 
have approximately 10-20 yards to stop 
following crossing the finish line. This made it 
difficult for the athlete to slowly decrease her 
speed and heart rate without a sudden stop. The 
coach, patient and her parents, and the athletic 
trainer discussed the patient’s situation and needs 
and it was determined that an assistant coach 
would provide support to the patient at the finish 
line by catching her at the conclusion of her races. 
After catching the patient at the finish line, the 
coach would lay her down and the athletic trainer 
would help to monitor her heart rate and oxygen 
levels. Once the patient's heart rate was below 
130 beats per minute, she was able to stand. 
Following each race, the patient’s heart rate 
returned to normal and she recovered 
approximately 10 minutes after finishing the race.  

OUTCOMES 

This patient’s freshman and sophomore years of 
high school athletics were challenging in managing 
her symptoms until a correct diagnosis was 
obtained. When the correct doses of medication 
were prescribed and the patient and her 
healthcare team better understood her condition, 
the patient did not experience any episodes of 



Disablement Model Case Study: Running with Postural Orthostatic Tachycardia Syndrome 
 

 

49 
Copyright © by Indiana State University                                                                                Clinical Practice in Athletic Training  
All rights reserved. ISSN Online 2577-8188                                                                     Volume 4 – Issue 2 – September 2021 
 

syncope while participating in basketball. In her 
junior and senior year, the episodes of syncope 
were only experienced after completing a cross-
country race. Her coach was able to catch her 
following her finish. The coach and athlete would 
monitor her heart rate and oxygen levels via pulse 
oximeter. Support provided by the cross-country 
coaches and the athletic trainer at the finish line 
helped her to recover quickly and she was able 
continue competing throughout her high school 
career.  

DISCUSSION 

This case is unique because it is endurance and 
adrenaline driven. In fact, 50% of POTS patients 
show signs of a hyperadrenergic or high 
adrenaline state.11 Hyperadrenergic POTS 
patients have high levels of nor-epinephrine in 
their blood which are natural stimulants in the 
body.11 This can lead to an increase in heart rate 
and blood pressure. This patient experienced 
syncope episodes following long-endurance cross-
country races due to the abrupt stop at the finish 
line and resultant rapid drop in heart rate . Her 
tilt table test showed that she has 
hyperadrenergic POTS because her results varied 
after the sympathetic drug, isoproterenol, was 
introduced. Additionally, the patient would 
always pass the finish line before fainting, 
supporting the hyperadrenergic POTS diagnosis. 
Following the correct diagnosis and dosages for 
the patient’s medication, she would only faint 
after running a cross-country race. During cross 
country practices or basketball games, the patient 
was able to slowly decrease activity and reduce 
her heart rate through breathing techniques. 
During basketball games and practices, she was 
able to tell when her heart rate was too high, so 
she would let her coach know she needed a 
substitution. After coming out of the game or 
practice she would sit on the bench and hydrate 
until her heart rate was under control.  

Compared to other cases, this patient had a mild 
case of POTS, which was managed through 
medications and modifications to sport 
participation. Some cases of POTS are more 
severe and have a greater effect on the patient’s 
daily activities. For example, two cases were 
presented detailing the symptoms of two young, 
Caucasian females. The first case included a 20-
year-old female who showed acute onset 
episodes of fainting upon sitting up, dizziness, 
slowing of speech, and the inability to contract 
muscles in the bladder.12 This patient was treated 
with 20 mg of propranolol, which is similar to the 
beta blocker the patient in the current case was 
prescribed. With the help of the medication, the 
patient only had short periods of dizziness 
following the diagnosis.12 The second case 
included a 19-year-old who showed acute onset 
of dizziness with syncope events.12 This patient 
was first treated with fludrocortisone and 
compression stockings. The patient also received 
500 mg of methylprednisolone for five days for 
suspected autonomic neuropathy.12 These two 
cases were unique because they started with an 
acute onset and the symptoms were fully 
disabling. Variation in onset, intensity and type of 
symptoms in those experiencing POTS could make 
diagnosis difficult. If POTS is not properly treated, 
the syndrome can greatly impact not just athletic 
activity, but activities of daily living. Proper 
communication between providers on the 
healthcare team can speed the delivery of an 
accurate diagnosis, aid in the development of a 
patient care plan, and assist the athlete in 
managing their symptoms.   

This case presented with strengths and limitations. 
Overall, the patient and her family were very well 
informed and cooperative in providing 
information to inform this case. For being so young 
in experiencing a health condition such as POTS, 
this patient was a very good communicator and 
became an advocate for her own healthcare. 
Educating and empowering high school patients to 
communicate and manage their own health 



Disablement Model Case Study: Running with Postural Orthostatic Tachycardia Syndrome 
 

 

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Copyright © by Indiana State University                                                                                Clinical Practice in Athletic Training  
All rights reserved. ISSN Online 2577-8188                                                                     Volume 4 – Issue 2 – September 2021 
 

conditions is extremely important. Athletic trainers, 
parents, and coaches can work together to help 
the high school patient-athlete in how to best 
manage their condition to be able to compete at 
a desired level. This patient took time to 
understand her condition, understand her 
condition, learned how to manage her symptoms, 
and she communicated well with all athletic 
trainers involved in her care – at home, and while 
traveling for competitions.  

CLINICAL BOTTOM LINE 

Although POTS is not extremely prevalent in 
athletic training clinical practice, it is vital for 
athletic trainers to be educated on the signs and 
symptoms of POTS and understand that it can 
affect each patient differently. The signs and 
symptoms of POTS may mimic many other 
pathologies which may lead to misdiagnoses and 
ineffective treatments. Athletic trainers should 
urge patients and their parents to seek several 
opinions when symptoms include light‐headedness, 
fatigue, sweating, anxiety, palpitations, exercise 
intolerance and syncope or near-syncope when 
standing or after exercise. When correctly 
diagnosed, POTS can be managed with patient 
education, advocacy and strong communication. 
Further, collaboration between 
healthcare providers to create an individual plan 
for the patient can also contribute to the 
management of POTS. In this case, the patient’s 
cardiologist, parents, coaches, athletic trainers, 
and the patient were all closely involved in her 
care plan. With a few simple modifications to an 
athlete’s procedure, close monitoring by athletic 
trainers, and routine checkups with a cardiologist, 
POTS symptoms can be managed and patient-
athletes can continue competing at high levels in 
various endurance sports. 

REFERENCES 

1. Agarwal AK, Garg R, Ritch A, Sarkar P. 
Postural orthostatic tachycardia syndrome. 
Postgrad Med J. 2007;83(981):478-480. 

https://doi.org/10.1136/pgmj.2006.05504
6.  

2. Grubb BP. Postural tachycardia syndrome. 
Circulation. 2008;117(21):2814-2817. 
https://doi.org/10.1161/circulationaha.107
.761643.  

3. Grubb BP, Kanjwal Y, Kosinski DJ. The 
postural tachycardia syndrome: a concise 
guide to diagnosis and management. J 
Cardiovasc Electrophysiol. 2006;17(1):108-
112. https://doi.org/10.1111/j.1540-
8167.2005.00318.x.  

4. Benarroch EE. Postural tachycardia syndrome: 
a heterogeneous and multifactorial disorder. 
Mayo Clin Proc. 2012;87(12):1214-1225. 
https://doi.org/10.1016/j.mayocp.2012.08
.013. 

5. Sletten DM, Weigand SD, Low PA. 
Relationship of Q-sweat to quantitative 
sudomotor axon reflex test (QSART) volumes. 
Muscle Nerve. 2010;41(2):240-246. 
https://doi.org/10.1002/mus.21464.  

6. Illigens BM, Gibbons CH. Sweat testing to 
evaluate autonomic function. Clin Auton Res. 
2009;19(2):79-87. 
https://doi.org/10.1007/s10286-008-
0506-8.  

7. Fedorowski A. Postural orthostatic 
tachycardia syndrome: clinical presentation, 
aetiology and management. J Intern Med. 
2019;285(4):352-366. 
https://doi.org/10.1111/joim.12852.  

8. Waxenbaum JA, Reddy V, Varacallo M. 
Anatomy, Autonomic Nervous System. 
Treasure Island (FL): StatPearls Publishing; 
2021. 
https://www.ncbi.nlm.nih.gov/books/NBK53
9845/.  

9. Greaney JL, Kenney WL, Alexander LM. 
Sympathetic regulation during thermal stress 
in human aging and disease. Auton Neurosci. 
2016;196:81-90. 
https://doi.org/10.1016/j.autneu.2015.11.
002.  

https://doi.org/10.1136/pgmj.2006.055046
https://doi.org/10.1136/pgmj.2006.055046
https://doi.org/10.1161/circulationaha.107.761643
https://doi.org/10.1161/circulationaha.107.761643
https://doi.org/10.1111/j.1540-8167.2005.00318.x
https://doi.org/10.1111/j.1540-8167.2005.00318.x
https://doi.org/10.1016/j.mayocp.2012.08.013
https://doi.org/10.1016/j.mayocp.2012.08.013
https://doi.org/10.1002/mus.21464
https://doi.org/10.1007/s10286-008-0506-8
https://doi.org/10.1007/s10286-008-0506-8
https://doi.org/10.1111/joim.12852
https://www.ncbi.nlm.nih.gov/books/NBK539845/
https://www.ncbi.nlm.nih.gov/books/NBK539845/
https://doi.org/10.1016/j.autneu.2015.11.002
https://doi.org/10.1016/j.autneu.2015.11.002


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Copyright © by Indiana State University                                                                                Clinical Practice in Athletic Training  
All rights reserved. ISSN Online 2577-8188                                                                     Volume 4 – Issue 2 – September 2021 
 

10. Information NCfB. PubChem Compound 
Summary for CID 4171, Metoprolol. 
https://pubchem.ncbi.nlm.nih.gov/compound
/Metoprolol. Accessed October 14, 2020. 

11. Arnold AC, Ng J, Raj SR. Postural tachycardia 
syndrome - Diagnosis, physiology, and 
prognosis. Auton Neurosci. 2018;215:3-11. 
https://doi.org/10.1016/j.autneu.2018.02.
005.  

12. Chung HY, Essig F, Wickel J, et al. Acute onset 
and severe manifestation of postural 
orthostatic tachycardia syndrome - Two cases. 
Clin Neurophysiol. 2020;131(1):158-159. 
https://doi.org/10.1016/j.clinph.2019.11.0
01.  

 

 

https://pubchem.ncbi.nlm.nih.gov/compound/Metoprolol
https://pubchem.ncbi.nlm.nih.gov/compound/Metoprolol
https://doi.org/10.1016/j.autneu.2018.02.005
https://doi.org/10.1016/j.autneu.2018.02.005
https://doi.org/10.1016/j.clinph.2019.11.001
https://doi.org/10.1016/j.clinph.2019.11.001

	ABSTRACT

