Postural Orthostatic Tachycardia Syndrome (POTS): A Review.

Postural orthostatic tachycardia syndrome (POTS) is a chronic autonomic disorder characterized by excessive orthostatic tachycardia and multisystem symptoms that affects an estimated 0.1% to 1% of the US population. POTS can substantially impair daily functioning and quality of life. Consensus criteria define POTS by chronic symptoms of orthostatic intolerance accompanied by a sustained heart rate increase of at least 30 beats/min (≥40 beats/min in adolescents aged 12-19 years) within 10 minutes of standing or head-up tilt, in the absence of orthostatic hypotension, defined as a decrease in either systolic blood pressure of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg with positional change. POTS symptoms may include palpitations, lightheadedness, nausea, vomiting, gastroparesis, anorexia, generalized weakness, and muscle pain, despite absence of structural pathology within cardiovascular, gastrointestinal, and neurological organs. POTS predominantly affects females (approximately 90% of cases), with peak incidence from ages 13 to 29 years. However, the true prevalence remains uncertain partly due to underrecognition and lack of a specific diagnostic code for POTS until 2022. Common symptoms include lightheadedness, palpitations, fatigue, cognitive dysfunction ("brain fog"), exercise intolerance, nausea, bloating, constipation, diarrhea, and sleep disturbance. In a survey of 4835 patients, approximately 70% reported substantial functional impairment and loss of school or work participation, and median diagnostic delay was 24 months. In 30% to 40% of cases, symptoms began within 3 months after infections, such as SARS-CoV-2, Epstein-Barr virus, and influenza. Initial evaluation should exclude other conditions that cause sinus tachycardia, including thyroid disease, adrenal insufficiency, pheochromocytoma, cardiomyopathy, valvular heart disease, congenital heart disease, chronic lung disease, medication effects (eg, stimulants, norepinephrine reuptake inhibitors, and diuretics), anemia, and dehydration. First-line treatment includes nonpharmacological strategies to improve cardiac preload, including increased fluid and sodium intake, lower-body compression garments; avoidance of heat exposure, dehydration, and prolonged standing; and structured supervised aerobic training. Pharmacological therapies should be individualized and may include β-blockers, ivabradine, midodrine, fludrocortisone, and pyridostigmine, although evidence supporting many therapeutic interventions is limited by small studies and lack of large, randomized trials. POTS is a chronic autonomic disorder associated with functional impairment and reduced quality of life that is diagnosed based on characteristic orthostatic symptoms in the absence of orthostatic hypotension after excluding alternative causes of sinus tachycardia. Treatment involves nonpharmacological measures (such as increased fluid and sodium intake), lower-body compression garments, structured exercise training, and individualized pharmacological therapy.