What is Postural Orthostatic Tachycardia Syndrome (POTS)?

From the Guidelines

Postural orthostatic tachycardia syndrome (POTS) is a condition characterized by an abnormal increase in heart rate that occurs after standing up from a lying position, with an excessive heart rate increase of at least 30 beats per minute (or exceeding 120 beats per minute) within 10 minutes of standing, without a significant drop in blood pressure, as defined by the 2022 ACC expert consensus decision pathway 1.

Key Features of POTS

• The primary feature is an excessive heart rate increase of at least 30 beats per minute (or exceeding 120 beats per minute) within 10 minutes of standing, without a significant drop in blood pressure.
• Patients typically experience symptoms such as lightheadedness, fatigue, brain fog, palpitations, exercise intolerance, and sometimes fainting.
• 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, as noted in the 2018 ESC guidelines for the diagnosis and management of syncope 1.

Management of POTS

• Patients should increase fluid intake (2-3 liters daily) and salt consumption (5-10g daily), as recommended in the 2022 ACC expert consensus decision pathway 1.
• Perform reclined exercises like swimming or rowing, use compression garments on the lower body, and practice gradual position changes.
• Medications may include beta-blockers (like propranolol 10-20mg twice daily), 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.

Pathophysiology of POTS

• POTS occurs because the autonomic nervous system fails to properly regulate blood vessel constriction when standing, causing blood to pool in the lower extremities and the heart to beat faster to compensate for reduced blood return to the heart, as explained in the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1.
• The pathophysiology is debated and likely heterogeneous, with deconditioning, immune-mediated processes, excessive venous pooling, and a hyperadrenergic state proposed as potential contributing factors, as discussed in the 2018 ESC guidelines for the diagnosis and management of syncope 1.

From the Research

Definition and Characteristics of Postural Orthostatic Tachycardia Syndrome (POTS)

• Postural Orthostatic Tachycardia Syndrome (POTS) is a variant of autonomic cardiovascular disorder characterized by an excessive increase in heart rate upon standing associated with light-headedness, headaches, chest pain, shortness of breath, and brain fog 2.
• POTS is a clinically heterogeneous disorder with multiple contributing pathophysiologic mechanisms manifesting as symptoms of orthostatic intolerance in the setting of orthostatic tachycardia (increase in heart rate by at least 30 beats per minute upon assuming an upright position) without orthostatic hypotension 3.
• Patients with POTS often experience a constellation of other typical symptoms including fatigue, exercise intolerance, and gastrointestinal distress 4.

Pathophysiology of POTS

• The etiology of POTS is largely unknown and often debilitating, with three major hypotheses about the pathophysiology of POTS being autoimmunity, abnormally increased sympathetic activity, and sympathetic denervation leading to central hypovolemia and reflex tachycardia 2.
• 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 3.
• A variety of pathophysiologies are involved in the abnormal postural tachycardia response; however, the pathophysiology of the syndrome is incompletely understood and undoubtedly multifaceted 4.

Diagnosis and Treatment of POTS

• The evaluation of a patient with suspected POTS should seek to establish the diagnosis, identify co-morbid conditions, and exclude conditions that could cause or mimic the syndrome 4.
• The approach to the treatment of POTS centers on treating the underlying pathophysiologic mechanism, with non-pharmacologic treatments (fluids, sodium intake, and compression stockings) and pharmacological therapies such as beta-blockers, ivabradine, fludrocortisone, and midodrine 3, 5.
• Lifestyle measures form the first line of therapy, followed by supplemental therapies such as iron, vitamin D, and α lipoic acid, with more specialized and nuanced alternatives including erythropoietin, IVIG, desmopressin, and cardiac neuromodulation 5.