What is Postural Orthostatic Tachycardia Syndrome (POTS)?

From the Guidelines

Postural Orthostatic Tachycardia Syndrome (POTS) is a disorder of the autonomic nervous system characterized by an abnormal increase in heart rate upon standing, without a corresponding drop in blood pressure, diagnosed when there is an increase in heart rate of at least 30 beats per minute (or reaching 120 beats per minute) within 10 minutes of standing, accompanied by symptoms that are relieved by lying down. POTS is a clinical syndrome usually characterized by frequent symptoms that occur with standing, such as lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, exercise intolerance, and fatigue, and an increase in heart rate of $30 bpm during a positional change from supine to standing (or $40 bpm in those 12–19 y of age), in the absence of orthostatic hypotension (OH) 1. Common symptoms of POTS include:

• Lightheadedness
• Fatigue
• Brain fog
• Palpitations
• Exercise intolerance
• Fainting Treatment typically involves both non-pharmacological and pharmacological approaches, including:
• Increasing fluid intake (2-3 liters daily)
• Increasing salt consumption (8-10g daily)
• Wearing compression garments
• Performing reclined exercises
• Implementing a gradual upright training program
• Medications such as beta-blockers like propranolol (10-20mg as needed), fludrocortisone (0.1-0.2mg daily) to increase blood volume, midodrine (2.5-10mg three times daily) to constrict blood vessels, or ivabradine (2.5-7.5mg twice daily) to reduce heart rate without affecting blood pressure 1. POTS occurs because the body fails to properly regulate blood flow when changing positions, causing blood to pool in the lower extremities and triggering an excessive heart rate response as the body attempts to maintain adequate blood flow to the brain and vital organs. The pathophysiology of POTS is debated and likely heterogeneous, with proposed mechanisms including deconditioning, immune-mediated processes, excessive venous pooling, and a hyperadrenergic state 1. POTS is frequently associated with deconditioning, recent infections, chronic fatigue syndrome, joint hypermobility syndrome, and a spectrum of non-specific symptoms such as headache and chest pain 1. History taking in patients with orthostatic intolerance may reveal symptoms that develop upon standing, are relieved by sitting or lying, and may be worse in the morning, with heat exposure, and after meals or exertion 1. The diagnosis of POTS is based on a thorough history, physical examination, and eyewitness observation, if available, as well as ancillary tests such as active standing test or tilt-table test 1. It is essential to differentiate POTS from other forms of orthostatic intolerance, such as initial OH, classical OH, delayed OH, and orthostatic vasovagal syncope, which have distinct pathophysiologies and treatment approaches 1. In summary, POTS is a complex disorder that requires a comprehensive approach to diagnosis and treatment, taking into account the individual patient's symptoms, medical history, and response to therapy.

From the Research

Definition of POTS

• Postural Orthostatic Tachycardia Syndrome (POTS) is a form of cardiovascular autonomic disorders characterized by orthostatic intolerance and a symptomatic increase in heart rate upon standing 2.
• POTS is a variant of autonomic cardiovascular disorder characterized by an excessive increase in heart rate upon standing associated with various symptoms such as light-headedness, headaches, and shortness of breath 3.
• It is a heterogeneous group of conditions characterized by autonomic dysfunction and an exaggerated sympathetic response to assuming an upright position 4.

Pathophysiology and Symptoms

• The pathophysiology of POTS is complex and multifactorial, involving three primary phenotypes: hyperadrenergic, neuropathic, and hypovolemic 2.
• Patients with POTS often experience symptoms such as dizziness, weakness, rapid heartbeat, and palpitation on standing, as well as physical deconditioning, headache, and gastrointestinal disorders 5.
• The onset of POTS may be precipitated by immunological stressors such as viral infection, vaccination, trauma, pregnancy, surgery, or psychosocial stress 5, 6.

Diagnosis and Management

• The diagnosis of POTS is typically established through a head-up tilt test with non-invasive beat-to-beat haemodynamic monitoring 5.
• Management of POTS typically begins with patient education and non-pharmacologic treatment options, such as increased fluid and salt intake, compression garment use, and physical reconditioning 2, 6.
• Various medications may be used to address specific symptoms, but there are currently no FDA-approved medications for the treatment of POTS, and evidence for many of the medications used to treat POTS is limited 2, 6.