Clinical Correlates of Efficacy of Pyridostigmine in the Treatment of Orthostatic Hypotension.

Background: The cholinesterase inhibitor pyridostigmine is used to treat orthostatic hypotension by facilitating cholinergic neurotransmission in autonomic ganglia, thereby harnessing residual sympathetic tone to increase blood pressure (BP) preferentially in the upright posture. We hypothesized that less severe autonomic impairment was associated with greater pressor responses to pyridostigmine.

Methods: To identify predictors of pressor response, linear regression analyses between the effect of pyridostigmine on upright BP and markers of autonomic impairment were retrospectively conducted on 38 patients who had a medication trial with pyridostigmine (60 mg single dose).

Blood volume deficit in postural orthostatic tachycardia syndrome assessed by semiautomated carbon monoxide rebreathing.

Purpose: The semiautomated carbon monoxide (CO) rebreathing method has been introduced as a noninvasive and radiation-free blood volume estimation method. We tested whether the semiautomated CO rebreathing method can detect the blood volume deficit in postural orthostatic tachycardia syndrome (POTS). In addition, we explored the relationship between blood volume estimated from CO rebreathing and body impedance.

Impaired parasympathetic function in long-COVID postural orthostatic tachycardia syndrome - a case-control study.

Purpose: Eighty percent of patients infected by SARS-CoV-2 report persistence of one symptom beyond the 4-week convalescent period. Those with orthostatic tachycardia and orthostatic symptoms mimicking postural tachycardia syndrome, they are defined as Long-COVID POTS [LCP]. This case-control study investigated potential differences in autonomic cardiovascular regulation between LCP patients and healthy controls.

Adrenal gland response to adrenocorticotropic hormone is intact in patients with postural orthostatic tachycardia syndrome.

Background: Many patients with postural orthostatic tachycardia syndrome (POTS) are hypovolemic with plasma volume deficits of 10-30 %. Some also have low levels of aldosterone and diminished aldosterone-renin ratios despite elevations in angiotensin II, pointing to potential adrenal dysfunction. To assess adrenal gland responsiveness in POTS, we measured circulating levels of aldosterone and cortisol following adrenocorticotropin hormone (ACTH) stimulation.

Symptoms of postural orthostatic tachycardia syndrome in pregnancy: a cross-sectional, community-based survey.

Objective: To evaluate the relationship between postural orthostatic tachycardia syndrome (POTS) and pregnancy.

Design: Cross-sectional survey.

Setting: International.

Use of Valsalva Maneuver to Detect Late-Onset Delayed Orthostatic Hypotension.

Background: Standard autonomic testing includes a 10-minute head-up tilt table test to detect orthostatic hypotension. Although this test can detect delayed orthostatic hypotension (dOH) between 3 and 10 minutes of standing, it cannot detect late-onset dOH after 10 minutes of standing.

Methods: To determine whether Valsalva maneuver responses can identify patients who would require prolonged head-up tilt table test to diagnose late-onset dOH; patients with immediate orthostatic hypotension (onset <3 minutes; n=176), early-onset dOH (onset between 3 and 10 minutes; n=68), and late-onset dOH (onset >10 minutes; n=32) were retrospectively compared with controls (n=114) with normal head-up tilt table test and composite autonomic scoring scale score of 0.

Effects of Atomoxetine for the Treatment of Neurogenic Orthostatic Hypotension in Patients With Alpha-synucleinopathies: A Systematic Review of Randomized Controlled Trials and a Focus-Group Discussion.

Background And Purpose: Neurogenic orthostatic hypotension (nOH) is one of the most important nonmotor symptoms in patients with α-synucleinopathies. Atomoxetine is a selective norepinephrine transporter blocker that is a treatment option for nOH. This systematic review and expert focus-group study was designed to obtain evidence from published data and clinical experiences of Korean movement-disorder specialists about the efficacy and safety of atomoxetine for the pharmacological treatment of nOH in patients with α-synucleinopathies.

Continuous Positive Airway Pressure for the Treatment of Supine Hypertension and Orthostatic Hypotension in Autonomic Failure.

Background: Supine hypertension affects most patients with orthostatic hypotension (OH) due to autonomic failure, but it is often untreated for fear of worsening OH. We hypothesized that increasing intrathoracic pressure with continuous positive airway pressure (CPAP) had a Valsalva-like blood-pressure-lowering effect that could be used to treat nocturnal supine hypertension in these patients, while reducing nocturnal pressure diuresis and improving daytime OH.

Methods: In Protocol 1, we determined the acute hemodynamic effects of increasing levels of CPAP (0, 4, 8, 12, and 16 cm HO, 3 minutes each) in 26 patients with autonomic failure and supine hypertension studied while awake and supine.

Worsening Postural Tachycardia Syndrome Is Associated With Increased Glucose-Dependent Insulinotropic Polypeptide Secretion.

Background: Postural tachycardia syndrome (POTS) is characterized by excessive upright tachycardia and disabling presyncopal symptoms, which are exacerbated after consuming a high-carbohydrate meal; it is unknown, however, what is the precise underlying mechanism. We seek to investigate the effect of glucose intake on orthostatic hemodynamic changes and gastrointestinal hormone secretion in POTS.

Methods: Prospective, case-control study, 12 women with POTS who reported a postprandial worsening of their POTS symptoms and 13 age-matched female controls received 75-g oral glucose and 20 mg/kg acetaminophen to assess nutrient absorption.

Advances in the Pathophysiology and Management of Supine Hypertension in Patients with Neurogenic Orthostatic Hypotension.

Purpose Of Review: Patients with neurogenic orthostatic hypotension (OH) frequently have hypertension in the supine position (sHTN). We review the controversies surrounding the need and safety of treating sHTN in patients with OH.

Recent Findings: The presence of sHTN complicates the management of OH because treatment of one can worsen the other.

Symptom Presentation and Access to Medical Care in Patients With Postural Orthostatic Tachycardia Syndrome: Role of Sex.

Background: Postural orthostatic tachycardia syndrome (POTS) is a chronic form of orthostatic intolerance that primarily impacts female patients of childbearing age. The role of sex differences in POTS is not well understood. We sought to identify sex differences in diagnosis, symptoms, comorbidities, and treatments in female and male patients diagnosed with POTS.

Effect of nitroglycerin on splanchnic and pulmonary blood volume.

Background: Sublingual nitroglycerin (SL NTG) is useful for treating acute decompensated heart failure, possibly by increasing splanchnic capacitance and reducing left ventricular (LV) preload. We evaluated a radionuclide method to study these effects, initially in subjects without heart failure.

Methods And Results: Red blood cells were labelled by an in vitro method.

Transdermal auricular vagus stimulation for the treatment of postural tachycardia syndrome.

Postural Tachycardia Syndrome (POTS) is a chronic disorder characterized by symptoms of orthostatic intolerance such as fatigue, lightheadedness, dizziness, palpitations, dyspnea, chest discomfort and remarkable tachycardia upon standing. Non-invasive transdermal vagal stimulators have been applied for the treatment of epilepsy, anxiety, depression, headache, and chronic pain syndromes. Anti-inflammatory and immunomodulating effects after transdermal vagal stimulation raised interest for applications in other diseases.

Ganglionic Acetylcholine Receptor Antibodies in Postural Tachycardia Syndrome.

Objective: Postural tachycardia syndrome (POTS), the most common form of dysautonomia, may be associated with autoimmunity in some cases. Autoantibodies against the ganglionic acetylcholine receptor (gAChR) have been reported in a minority of patients with POTS, but the prevalence and clinical relevance is unclear.

Methods: Clinical information and serum samples were systematically collected from participants with POTS and healthy control volunteers (n = 294).

Implications of Antimuscarinic Autoantibodies in Postural Tachycardia Syndrome.

Functional autoantibodies directed to the M2 muscarinic acetylcholine receptor (M2R) could affect the heart rate directly by altering cardiac M2R activity and/or indirectly by changing vagal-mediated cardiac M2R activity. We measured M2R autoantibody activity in sera from 10 subjects with postural tachycardia syndrome (POTS) and 5 healthy control subjects using a cell-based bioassay. Half of the POTS subjects demonstrated presence of elevated M2R autoantibody activity, while no significant M2R autoantibody activity was found in the healthy subjects.

Effect of High Dietary Sodium Intake in Patients With Postural Tachycardia Syndrome.

Background: High sodium intake is recommended for the treatment of postural tachycardia syndrome (POTS) to counteract the hypovolemia and elevated plasma norepinephrine that contribute to excessive orthostatic tachycardia, but evidence of its efficacy is not available.

Objectives: This study tested whether a high sodium (HS) diet reduces orthostatic tachycardia (Δ heart rate) and upright heart rate compared with a low sodium (LS) diet in POTS patients, and secondarily its effect on plasma volume (PV) and plasma norepinephrine.

Methods: A total of 14 POTS patients and 13 healthy control subjects (HC), age 23 to 49 years, were enrolled in a crossover study with 6 days of LS (10 mEq sodium/day) or HS (300 mEq sodium/day) diet.

Local Passive Heat for the Treatment of Hypertension in Autonomic Failure.

Background Supine hypertension affects a majority of patients with autonomic failure; it is associated with end-organ damage and can worsen daytime orthostatic hypotension by inducing pressure diuresis and volume loss during the night. Because sympathetic activation prevents blood pressure (BP) from falling in healthy subjects exposed to heat, we hypothesized that passive heat had a BP-lowering effect in patients with autonomic failure and could be used to treat their supine hypertension. Methods and Results In Protocol 1 (n=22), the acute effects of local heat (40-42°C applied with a heating pad placed over the abdomen for 2 hours) versus sham control were assessed in a randomized crossover fashion.

High-sodium diet does not worsen endothelial function in female patients with postural tachycardia syndrome.

Purpose: Postural tachycardia syndrome (POTS), a syndrome characterized by orthostatic symptoms and a heart rate increase of at least 30 beats per minute in the absence of hypotension upon standing, is often accompanied by increased sympathetic activity and low blood volume. A common non-pharmacologic recommendation for patients with POTS is a high-sodium (HS) diet with the goal of bolstering circulating blood volume. The objective of this study is to assess the effects of 6 days of a HS diet on endothelial function in POTS.

Postural orthostatic tachycardia syndrome is associated with significant employment and economic loss.

Background: Postural orthostatic tachycardia syndrome (POTS) is a debilitating form of chronic orthostatic intolerance that primarily affects women and causes substantial impairment in quality of life and function. Yet, there is minimal literature describing the employment and economic consequences of POTS. We explored these aspects of the POTS patient experience through a self-reported study designed using community-based participatory research principles.

A comparison of health-related quality of life in autonomic disorders: postural tachycardia syndrome versus vasovagal syncope.

Purpose: Postural tachycardia syndrome (POTS) and vasovagal syncope (VVS) are two disorders of orthostatic intolerance which are often misdiagnosed as the other. In each case, patients experience a reduced health-related quality of life (HRQoL) compared to healthy populations. This study was conducted to test the hypothesis that HRQoL is worse in POTS.

Impaired Endothelial Function in Patients With Postural Tachycardia Syndrome.

The purpose of this study is to evaluate endothelial function in postural tachycardia syndrome (PoTS), a poorly understood chronic condition characterized by a state of consistent orthostatic tachycardia (delta heart rate ≥30 beats per minute) upon standing without orthostatic hypotension. Nineteen patients with PoTS and 9 healthy controls were studied after 3 days of a fixed, caffeine-free, normal sodium (150 milliequivalents/day) diet. All participants underwent autonomic function testing, including sinus arrhythmia, valsalva maneuver, hyperventilation, cold pressor, handgrip, and a standing test with catecholamine measurements, followed by endothelial function testing.

Restless legs syndrome is increased in postural orthostatic tachycardia syndrome.

Study Objectives: Postural orthostatic tachycardia syndrome (POTS) and restless legs syndrome (RLS) are both characterized by sleep disturbance along with autoimmune/inflammatory features and autonomic dysfunction. However, to our knowledge, there has been no direct study looking at the prevalence of RLS in patients with POTS patients compared with healthy participants (controls).

Methods: Ninety-six physician-diagnosed patients with POTS (89 female and 7 male) and 130 controls (99 female and 31 male) were administered the Cambridge Hopkins questionnaire.