Postural Tachycardia Syndrome (POTS)

Original Editors - Brian Blevins and Allison Lesousky from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Allison Lesousky, Brian Blevins, Kim Jackson, Lucinda hampton, Chioma Clara Okeakpu, Admin, Elaine Lonnemann, Thomas Janicky, Hugh Jones, WikiSysop, Heba El Saeid, 127.0.0.1, Rachael Lowe, Wendy Walker, Karen Wilson and Vidya Acharya  

Definition/Description

Postural Orthostatic Tachycardia Syndrome (POTS ) is a chronic disorder described as a patient's intolerance to the change of body position from supine to an upright position characterized by excessive increase in heart rate in the absence of orthostatic hypotension POTS is theorized to be due to an autonomic dysregulation regulating blood flow and more specifically its' responsibility to control cerebral blood flow. POTS be classified as; primary or idiopathic with no known cause; secondary, which arises from a known disease or disorder.

Prevalence

The prevalence of POTS has not been properly studied although it has estimates which is based largely on clinical experience and this estimates range from 0.2%-1% of the US population which is approximately 1–3 million affected persons. It occurs more frequently in females (adolescent and young adult) than in men and the older population. A large survey of over 4800 patients with a self-reported POTS diagnosis recorded that the most common age at onset was 14 years.

Characteristics/Clinical Presentation

POTS is a complex, multi-system, chronic disorder of the autonomic nervous system characterized by orthostatic intolerance with excessive heart rate (HR) increase and symptoms on standing while blood pressure is maintained. Orthostatic symptoms improve rapidly after returning to a supine position. Apart from the abnormal circulatory response to standing, patients with POTS may experience a variety of other persistent symptoms such as low energy, headache, cognitive impairment, muscle fatigue, chest pain, and non-specific generalized weakness, along with numerous gastrointestinal symptoms. POTS has been defined by major international neurologic, autonomic, cardiac, and pediatric societies to include the following:

1. A sustained HR increment of not less than 30 beats/minute within 10 min of standing or head-up tilt. For individuals who are 12 to 19 years old, the required HR increment is at least 40 beats/minute; and

2. An absence of orthostatic hypotension (i.e. no sustained systolic blood pressure [BP] drop of 20 mmHg or more); and

3. Frequent symptoms of orthostatic intolerance during standing, with rapid improvement upon return to a supine position. Symptoms may include lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, and fatigue; and

4. Duration of symptoms for at least 3 months; and 5. Absence of other conditions explaining sinus tachycardia such as anorexia nervosa, primary anxiety disorders, hyperventilation, anemia, fever, pain, infection, dehydration, hyperthyroidism, pheochromocytoma, use of cardioactive drugs (e.g. sympathomimetics, anticholinergics) or severe deconditioning caused by prolonged bed rest                

Associated Co-morbidities

POTS is primarily idiopathic, but secondary POTS is characterized by the presence of a disease or disorder. The most common associated co-morbity that presents with POTS is Myalgic Encephalomyelitis or Chronic Fatigue Syndrome (CFS). Currently it is thought that POTS may cause CFS with patients demonstrating orthostatic intolerance and the treatment of POTS usually improves the disabling fatigue in patients with both POTS and CFS. Other associated co-morbidities are found to include, vasovagal syncope, or specifically named "neurocardiogenic syncope" characterized by similar symptoms such as syncope upon position change and autonomic dysregulationPOTS has been also associated with patients with fibromyalgia due to the improvement in myofascial and neuropathic pain symptoms when treated for POTS. Irritable Bowel Syndrome often associated with POTS due to the presence of the related autonomic dysfunction. It has also been proposed that Ehlers-Danlos Syndrome (EDS), a connective tissue disorder, is found in some POTS patients . This syndrome tends to occur with POTS due to the abnormal connective tissue development in dependent blood vessels which allow excessive amounts of blood to pool in the lower limbs when they stand.

Other associated co-morbidities include:

• Addison's Disease
• Anemia
• Diabetes
• Guillan-Barré & Systematic Lupus Erythematosus
• Cardiovascular disease/atrophy
• Gastric Bipass Surgery
• Lesions of the Autonomic Nervous System
• Syringomyelia
• Thyroid Disease
• Tumors

Medications

There are many medical interventions available for the management of POTS. The primary drug of choice for symptoms relief in POTS is a fludrocortisone used to increase sodium retention in order to increase blood volume which subsequently increases blood pressure. Beta-blockers are also often prescribed in order to control the signature excessive heart rate of POTS. The stimulant midodrine is often used to treat orthostatic hypotension by causing vasoconstriction which increases blood pressure allowing blood to return to the upper body more efficiently. Beta-blockers are often used in conjunction with midodrine due to the tendancy for supine hypertension. Furthermore, with the likely involvement of the autonomic nervous system, antidepressants such as SSRI's have been found to be effective in re-establishing proper autonomic functioning and there-by regulating blood pressure in all positions

Diagnostic Tests/Lab Tests/Lab Values

Currently, POTS is difficult to diagnose and patients usually endure symptoms for a year or longer. However, once all other differentials are excluded, patients are often diagnosed with POTS through a tilt table test. A patient is strapped to a mechanical tilt table in which it will tilt them upright at angles of at least 60 degrees. Measurements of HR and BP are taken in supine and then at intervals during the change in position and this test can take up to 40 minutes or until the patient faints Often the tilt table test is used concurrently with a transcranial doppler ultrasonography which proves useful in determining cerebral blood flow perfusion during position changes. It is very important to rule out all differentials that could indicate a more serious systemic pathology such as Addison's, Lyme Disease, thyroid dysfunction, etc.

Etiology/Causes

The current etiology of POTS are not fully known. POTS is theorized to be due to an autonomic dysregulation regulating blood flow and more specifically its' responsibilty to control cerebral blood flow. Many patients will develop POTS in their teens after periods of rapid growth, especially in males, and will see symptom improvements as age advances. Other patients will develop POTS after a significant viral or bacterial infections such as pneumonia, or even after trauma such as an MVA. Women also tend to develop symptoms of POTS after pregnancy, in which prognosis for symptoms tend to be less optimistic.

Systemic Involvement

POTS can have significant systemic involvement given all other differentials are excluded. Systemic involvement usually involves hypo-perfusion of blood to upper body, and in particular the organs. This includes symptoms presenting related to reduced cerebral blood flow such as decreased mental stamina, depression, difficulty finding the right word, impaired concentration, sleep disorders. Symptoms can also present as hypo-perfusion to viscera and/or related to autonomic dysregulation such as abdominal pain or discomfort, bloating, constipation, diarrhea, nausea & vomiting . Other systemic involvement usually related to chronic fatigue and general malaise, thus the common co-diagnosis of Chronic Fatigue Syndrome.

Medical Management

The survery by Junghans-Rutelonis and his colleagues suggests adopting an interdisciplinary team to determine the ideal combinations of treatments (pharmacologic, physical therapy, integrative medicine, cognitive-behavioral therapy, psychoeducation approaches) that address the child's condition. Management includes the following recommendations:

• Dietary Recommendations - Patients are encouraged to manage their symptoms through diet, including a high fluid intake (2L/day) and at least 3-5 g of salt.

• Non-Pharmacological Treatment - Acute blood volume expansion has been shown to be effective at controlling the heart rate and acutely improving symptoms.  Jacob et al. found that 1L of physiological saline infused intravenously over 1 hour decreased the orthostatic tachycardia immediately following the infusion.

• Pharmacological Treatment - If non pharmacological treatments are not successful medications may be trialled. There are no specific types of drugs treatments for POTS because it primarily depends on the type of etiology responsible for the syndrome. Drugs that have been shown to produce some success include: fludrocortisone, β-blockers, selective serotonin reuptake inhibitors (SSRIs), and norepinephrine reuptake inhibitor (NRI).

• Fludrocortisone helps by increasing the sodium and fluid retention, while also sensitizing α-adrenergic receptors.
• β-blockers can be used to treat the hyperadrenergic form of POTS
• SSRIs increase nerve stimulation and communication of the standing vasoconstriction reflex, which reduces the venous blood pooling and in turn increased the patient’s orthostatic tolerance. In symptomatic patients, the addition of a NRI would also be beneficial.

A multi-disciplinary approach is required as the patient’s activities of daily living become increasingly more difficult and require help in all aspects. It is essential to involve the knowledge of occupational/physical therapists, social workers, and clinical psychologists as well as legal counsellors.

Physiotherapy Management

Physiotherapy management focuses on patient education and exercises.

Patient Education:

• the patient’s understanding of respiratory physiology, specifcally respiratory control and normal breathing pattern
• the mind—body link and how external factors such as anxiety, stress and lifestyle influences breathing patterns resulting in breathlessness.

Breathing Re-training: This include the following techniques

• breathing control at rest and during activity.
• controlled pause technique.

Exercise/Physical Training: Exercise is an important component in the management of POTS especially in the presence of deconditioning. The long-term benefits of exercise such as increased blood volume, stroke volume and cardiac output, enhanced vascular pressure by enlarged muscle tissue and changes to the baroreflex are all perceived to counteract orthostatic intolerance. Patients with POTS find it difficult to adhere to exercise programs because they perceive physical activity/exercise as adversely affecting their condition in the short term, Therefore the training program should aim to improve physical fitness, while avoiding excessive stress on the circulatory system. Also, Clinicians need to be aware that some patients cannot tolerate or benefit from exercise until they have achieved better medication control of their POTS. As a result, clinicians emphasizes the importance of an individualized mix of exercise and medication management, not a rigid adherence to an “exercise first” philosophy. Exercise training incorporated in the presence of POTS may include;

1. Aerobic training
2. Resistance training
3. isometric exercises, etc.

In performing these programs , certain factors are to be noted ;

1. Positioning: Recent studies stated that patients with POTS respond to exercise with an insuffcient increase in stroke volume, which can lead to symptoms of circulatory distress (dyspnea, feeling faint, lightheadedness, weakness). Therefore, it is advised that exercises should be done in the horizontal position e.g. rowing, reclined cycling, swimming, supine leg press as it is more tolerable and effective in the first stages of training.
2. Intensity and Frequency: Individualized training and progress is vital. Performing a submaximal exercise test, such as the Astrand-Saltin incremental treadmill protocol, to estimate the patient’s maximum heart rate. However, upright treadmill tests may not be possible in clinical settings hence the need for other submaximal tests can be considered, such as the incremental shuttle walk test or cycle ergometry. For patients using medication that controls heart rate, including β-blocking agents or ivabradine, the Borg scale for the rating of perceived exertion (RPE) can be used to estimate exercise intensity during the training sessions, since heart rate is not a valid parameter in this group.

Other exercises include closed- chain exercises like bridging and leg-press , etc. This physiotherapy treatment addresses joint stability, muscle strength and motor control.

The following video clip shows a young woman's journey of 15 years living with POTS and her symptoms and treatment approach. Including; Inappropriate Sinus Tachycardia Syndrome; Myalgic Encephalomyelitis or Chronic Fatigue Syndrome; Pheochromocytoma; Neurally Mediated Syncope 

Case Reports/ Case Studies

• Anaesthetic management of a parturient with the postural orthostatic tachycardia: a case report
• Study: Postural Orthostatic Tachycardia Syndrome
• Care of an adolescent with postural orthostatic tachycardia syndrome
• A review of postural orthostatic tachycardia syndrome
• POTS following traumatic stress

Resources

• National Dysautonomia Research Foundation (NDRF)
• Dysautonomia Youth of America, Inc. (DYNA)
• POTS Place: A Guide to Postural Orthostatic Tachycardia Syndrome (DINET)
• NINDS Postural Tachycardia Syndrome Information Page
• Chronic Fatigue Immune Dysfunction Syndrome (CFIDS) Association
• North American Society for Pacing and Electrophysiology (NASPE)
• Vanderbilt Autonomic Center
• The Mayo Clinic, Rochester, MN
• The American Association for Chronic Fatigue Syndrome (AACFS)
• New Jersey CFS Center
• CDC (Centers for Disease Control and Prevention): CFS Home Page
• My Heart POTS Syndrome Center