From the Guidelines
Postural Orthostatic Tachycardia Syndrome (POTS) is a clinical syndrome characterized by frequent symptoms that occur with standing, such as lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, exercise intolerance, and fatigue, along with an increase in heart rate of ≥30 bpm during a positional change from supine to standing, without orthostatic hypotension.
Definition and Characteristics
POTS is a disorder of the autonomic nervous system, with symptoms that occur upon standing and are relieved by sitting or lying down. The condition is marked by an abnormal increase in heart rate, often >120 bpm, without a corresponding drop in blood pressure 1.
Key Features
Some key features of POTS include:
- Increase in heart rate of ≥30 bpm during a positional change from supine to standing (or ≥40 bpm in those 12–19 years of age) 1
- Absence of orthostatic hypotension (>20 mm Hg reduction in systolic BP) 1
- Symptoms that occur with standing, such as lightheadedness, palpitations, and fatigue, as well as those not associated with particular postures, like bloating and nausea 1
Diagnosis and Management
Diagnosis of POTS is based on a thorough history, physical examination, and eyewitness observation, if available. Management typically involves both non-pharmacological and pharmacological approaches, including increasing fluid and salt intake, wearing compression garments, and medications like beta-blockers and fludrocortisone 1.
Pathophysiology
The condition develops due to the autonomic nervous system's failure to properly regulate blood vessel constriction when standing, causing blood to pool in the lower extremities and triggering an excessive heart rate response as compensation.
From the Research
Definition and Characteristics of POTS
- Postural Orthostatic Tachycardia Syndrome (POTS) is a form of cardiovascular autonomic disorder characterized by orthostatic intolerance and a symptomatic increase in heart rate upon standing 2, 3, 4, 5, 6.
- It is marked by an excessive heart rate increase on standing, often accompanied by symptoms such as dizziness, weakness, rapid heartbeat, palpitation, headache, 'brain fog', dyspnoea, gastrointestinal disorders, and musculoskeletal pain 3, 4, 5, 6.
Pathophysiology and Phenotypes
- The pathophysiology of POTS is complex and multifactorial, with three primary phenotypes identified: hyperadrenergic, neuropathic, and hypovolemic 2, 3, 4, 6.
- Hyperadrenergic POTS is characterized by excessive norepinephrine production or impaired reuptake, leading to sympathetic overactivity 2, 3.
- Neuropathic POTS results from impaired vasoconstriction during orthostatic stress, while hypovolemic POTS is often triggered by dehydration and physical deconditioning 2, 3, 4.
Diagnosis and Treatment
- Diagnosis of POTS is typically established through a head-up tilt test with non-invasive beat-to-beat haemodynamic monitoring, or a standing test with serum norepinephrine levels and red-cell volumes 3, 4.
- Treatment approaches vary depending on the phenotype, but often involve lifestyle modifications such as increased fluid and salt intake, compression garment use, physical reconditioning, and postural training 2, 3, 4, 5, 6.
- Pharmacologic therapies may be used to manage specific symptoms, including beta-blockers for hyperadrenergic POTS, and agents that enhance vascular tone for neuropathic POTS 2, 3, 6.