The main characteristic of postural orthostatic tachycardia syndrome (POTS) is tachycardia when standing, without a drop in blood pressure. Patients describe lightheadedness and palpitations when upright, particularly when standing, which sometimes leads to syncope. Patients may experience impaired quality of life and functional disability, which can be economically devastating. (1-3) The syndrome is more common in girls and young women and has been associated with other disorders, like migraine and Ehlers-Danlos syndrome. (4) We discuss the diagnosis of POTS, conditions to consider in the differential diagnosis, associated disorders and the pharmacologic and nonpharmacologic management of patients with POTS, based on original research, narrative reviews and consensus statements (Box 1).
What is the definition of POTS?
Various professional societies in North America have published consensus criteria for the diagnosis of POTS, including the American Autonomic Society, (6) the Heart Rhythm Society, (7) the Canadian Cardiovascular Society (5) and, most recently, a POTS Working Group for the United States National Institutes of Health. (8) The consensus statements consistently require orthostatic tachycardia and symptomatic orthostatic intolerance to be chronic problems that coexist. The criteria for a diagnosis of POTS are listed in Box 2. Symptoms must occur after standing, with a marked increase in heart rate, but without a substantial drop in blood pressure. The presence of another condition that could explain the orthostatic tachycardia--such as anemia, anxiety, fever, pain, infection, dehydration, hyperthyroidism, pheochromocytoma, prolonged bed rest or the use of medications that can increase heart rate (including stimulants, diuretics and norepinephrine reuptake inhibitors) (9)--precludes the diagnosis of POTS.
The orthostatic tachycardia must occur in the absence of classical orthostatic hypotension, but transient initial orthostatic hypotension (10) does not preclude a diagnosis of POTS. (5) The patient's heart rate should rise by at least 30 beats/min (or [greater than or equal to] 40 beats/min if patient is aged 12-19 yr) in at least 2 measurements taken at least 1 minute apart (Box 2). The Canadian Cardiovascular Society statement5 set a minimum supine heart rate of 60 beats/min to prevent the diagnosis of POTS being made in a patient with a low resting heart rate that increases to a normal level on standing.
It is physiologically normal for orthostatic tachycardia to vary slightly from day to day and for diurnal variability to exist such that greater orthostatic tachycardia occurs in the morning than later in the day.11 If a clinician has a high suspicion of POTS, but a patient does not meet the criterion for orthostatic tachycardia at their initial evaluation, reassessment at a later date is prudent, preferably in the morning.
What is the epidemiology and natural history of POTS?
Postural orthostatic tachycardia syndrome is one of the most common disorders of the autonomic nervous system, with an estimated prevalence of 0.1%-1%. (1,12,13) It usually affects adolescent girls and young adult women, (4) and so the prevalence is higher in this population and lower in men and older people. Postural orthostatic tachycardia syndrome is a heterogeneous syndrome, with multiple causes that can produce...