From the Guidelines
Postural Orthostatic Tachycardia Syndrome (POTS) is a condition characterized by an abnormal increase in heart rate when moving from lying down to standing up, accompanied by symptoms like dizziness, fatigue, and brain fog, and is defined by a sustained increase in heart rate of ≥30 bpm within 10 min of moving from a recumbent to a quiet standing position, in the absence of orthostatic hypotension. According to the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1, 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. 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. Symptoms associated with POTS include those that occur with standing, such as lightheadedness and palpitations, as well as systemic symptoms like fatigue, sleep disturbance, and migraine headaches 1. Some key points to note about POTS include:
- It 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.
- The standing heart rate is often >120 bpm 1.
- Treatment typically begins with non-pharmacological approaches, including increased fluid intake and salt consumption, compression garments, and a graduated exercise program, and may also involve medications like beta-blockers, fludrocortisone, and midodrine [@Example@]. Overall, the diagnosis of POTS should be based on a thorough history, physical examination, and eyewitness observation, if available, and treatment should be individualized to address the patient's specific symptoms and needs.
From the Research
Definition and Characteristics of Postural Orthostatic Tachycardia Syndrome (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, which can significantly impair patients' quality of life 2.
- POTS is a condition in which a change from a supine to an upright position causes an abnormally large increase in heart rate, which may be accompanied by a variety of physical complaints 3.
- The syndrome is characterized by an exaggerated increase in heart rate that occurs during standing, without orthostatic hypotension, and may present with palpitations, chest discomfort, shortness of breath, weakness, exercise intolerance, lightheadedness, presyncope, and syncope 4.
Pathophysiology and Mechanisms
- The pathophysiology of POTS is complex and multifactorial, involving three primary phenotypes: hyperadrenergic, neuropathic, and hypovolemic, each requiring tailored management strategies 2, 5.
- The three major pathophysiologic mechanisms include partial autonomic neuropathy, hypovolemia, and hyperadrenergic state, with patients often exhibiting overlapping characteristics from more than one of these mechanisms 5.
Diagnosis and Treatment
- The diagnosis of POTS can be established with a tilt-table test or a standing test, and serum norepinephrine levels and red-cell volumes may also be used 4.
- Treatment approaches for POTS include lifestyle modifications, such as increased fluid and salt intake, compression garment use, physical reconditioning, and postural training, as well as pharmacologic therapies to manage specific symptoms 2, 3, 4, 5.
- Pharmacologic therapies, such as beta-blockers, pyridostigmine, and midodrine, may be effective in managing symptoms of POTS, particularly in patients with hyperadrenergic or neuropathic phenotypes 2, 4, 6.