What is Postural Orthostatic Tachycardia Syndrome (POTS)?

From the Guidelines

Postural orthostatic tachycardia syndrome (POTS) is a condition that should be managed with a combination of non-pharmacological and pharmacological approaches, prioritizing the improvement of blood volume, reduction of heart rate, and enhancement of vascular tone to minimize orthostatic symptoms, as recommended by the most recent guidelines 1.

Definition and Pathophysiology

POTS is characterized by an abnormal increase in heart rate when moving from a lying to standing position, accompanied by symptoms like dizziness, fatigue, and brain fog. The pathophysiology is debated and likely heterogeneous, involving deconditioning, immune-mediated processes, excessive venous pooling, and a hyperadrenergic state 1.

Management

Management includes both non-pharmacological and pharmacological approaches. Non-pharmacological treatments are first-line and include:

• Increasing fluid intake (2-3 liters daily)
• Increasing salt consumption (10-12g daily)
• Wearing compression garments
• Performing reclined aerobic exercise gradually building to upright exercise
• Practicing counter-pressure maneuvers when feeling faint If these measures are insufficient, medications may be considered, including:
• Beta-blockers like propranolol (10-20mg as needed or 10-40mg twice daily)
• Fludrocortisone (0.1-0.2mg daily) to increase blood volume
• Midodrine (2.5-10mg three times daily) for vasoconstriction
• Pyridostigmine (30-60mg three times daily) 1.

Diagnosis and Associated Conditions

POTS is diagnosed based on a heart rate increase of ≥30 bpm during a positional change from supine to standing (or ≥40 bpm in those 12–19 y of age), and the absence of orthostatic hypotension (>20 mm Hg reduction in systolic BP) 1. 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.

From the Research

Definition and Characteristics of Postural Orthostatic Tachycardia Syndrome (POTS)

• POTS is a form of cardiovascular autonomic disorder characterized by orthostatic intolerance and a symptomatic increase in heart rate upon standing 2.
• It is defined by a heart rate increment of 30 beats/min or more within 10 minutes of standing or head-up tilt in the absence of orthostatic hypotension 3.
• Patients with POTS often experience symptoms such as fatigue, exercise intolerance, gastrointestinal distress, and cognitive and behavioral factors 4, 3.

Pathophysiology of POTS

• The pathophysiology of POTS is complex, multifactorial, and heterogeneous, involving impaired sympathetically mediated vasoconstriction, excessive sympathetic drive, volume dysregulation, and deconditioning 2, 3.
• Three primary POTS phenotypes have been identified: hyperadrenergic, neuropathic, and hypovolemic, each requiring tailored management strategies 2.

Management and Treatment of POTS

• First-line treatment for all patients focuses on lifestyle modifications, including increased fluid and salt intake, compression garment use, physical reconditioning, and postural training 2, 4.
• Pharmacologic therapies are primarily used to manage specific symptoms, with beta-blockers being effective for hyperadrenergic POTS, and agents that enhance vascular tone, such as pyridostigmine and midodrine, being effective for neuropathic POTS 2, 5.
• Pyridostigmine has been shown to improve symptoms of orthostatic intolerance in some patients with POTS, with a response rate of 43% in one study 5.
• Experimental therapies, such as cardiac neuromodulation, are being explored, and supplemental therapies like iron, vitamin D, and α lipoic acid may be considered 6.

Diagnosis and Evaluation 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 aims of evaluation in patients with POTS are to exclude cardiac causes of inappropriate tachycardia, elucidate the most likely pathophysiologic basis of postural intolerance, and assess for the presence of treatable autonomic neuropathies 3.