What causes worsening Postural Orthostatic Tachycardia Syndrome (POTS) with increased wakefulness after a stressful event, despite parasympathetic nervous system activation?

From the Guidelines

Worsening Postural Orthostatic Tachycardia Syndrome (POTS) with increased wakefulness after a stressful event, despite parasympathetic nervous system activation, is likely due to an underlying imbalance in the autonomic nervous system, where the sympathetic nervous system's "fight-or-flight" response dominates, leading to increased heart rate and blood pressure dysregulation. This condition is characterized by a constellation of symptoms, including frequent, recurrent, or persistent lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, exercise intolerance, and fatigue upon standing 1.

Key Factors Contributing to Worsening POTS

• Increased sympathetic nervous system activity, which can be triggered by stress, leading to an increase in heart rate and blood pressure
• Disruption of normal blood pressure and heart rate regulation, exacerbating POTS symptoms
• Potential underlying conditions, such as orthostatic intolerance, orthostatic tachycardia, or orthostatic hypotension, which can contribute to POTS symptoms

Management Strategies

• Calming techniques, such as deep breathing exercises, can help mitigate the effects of stress on the autonomic nervous system. Practicing deep breathing exercises for 5-10 minutes several times daily can help reduce sympathetic nervous system activity and promote parasympathetic nervous system activation.
• Staying well-hydrated with 2-3 liters of water daily and increasing salt intake to 3-5 grams per day, unless contraindicated by other health conditions, can help manage orthostatic symptoms.
• Physical counterpressure maneuvers, such as crossing legs when standing and wearing compression garments, can also help manage orthostatic symptoms.
• If symptoms persist beyond a week, consulting a healthcare provider is recommended, as they may prescribe medications like beta-blockers (e.g., propranolol) or midodrine for acute management.

Connection Between Stress and POTS

The connection between stress and POTS occurs because chronic stress hormones, such as cortisol and adrenaline, can disrupt autonomic nervous system balance, exacerbating the blood pooling and tachycardia that characterize POTS 1. This highlights the importance of managing stress and promoting autonomic nervous system balance to alleviate POTS symptoms.

From the Research

Pathophysiology of POTS

The worsening of Postural Orthostatic Tachycardia Syndrome (POTS) with increased wakefulness after a stressful event, despite parasympathetic nervous system activation, can be attributed to several factors. Some key points to consider include:

• POTS is a form of cardiovascular autonomic disorder characterized by orthostatic intolerance and a symptomatic increase in heart rate upon standing 2.
• The pathophysiology of POTS is complex and multifactorial, involving various mechanisms such as limited autonomic neuropathy, hyperadrenergic state, hypovolemia, venous pooling, and deconditioning 3.
• Anxiety and somatic hypervigilance play significant roles in POTS, and common comorbidities include visceral pain and dysmotility, chronic fatigue and fibromyalgia, migraine, joint hypermobility, mitral valve prolapse, and inappropriate sinus tachycardia 3.

POTS Phenotypes and Management

There are three primary POTS phenotypes: hyperadrenergic, neuropathic, and hypovolemic, each requiring tailored management strategies 2. Key points to consider include:

• Hyperadrenergic POTS is characterized by excessive norepinephrine production or impaired reuptake, leading to sympathetic overactivity, and beta-blockers may be an effective treatment option 2, 4.
• Neuropathic POTS results from impaired vasoconstriction during orthostatic stress and may respond to agents that enhance vascular tone, such as pyridostigmine and midodrine 2, 5.
• Hypovolemic POTS is often triggered by dehydration and physical deconditioning and responds primarily to volume expansion and exercise 2.

Treatment and Management

Treatment of POTS involves nonpharmacologic and pharmacologic approaches, with the objectives of increasing the time patients can stand, perform daily activities, and exercise, and avoiding syncope 3. Some key points to consider include:

• Lifestyle modifications, such as increased fluid and salt intake, compression garment use, physical reconditioning, and postural training, are first-line treatments for all POTS patients 2.
• Pharmacologic therapies are primarily used to manage specific symptoms, and the evidence supporting their efficacy is limited 2.
• Midodrine, an α1-adrenergic receptor agonist, may be an effective treatment for neuropathic POTS, but not for hyperadrenergic POTS 5.