Postural Tachycardia Syndrome Patients Research Articles

Orthostatic intolerance with tachycardia (postural tachycardia syndrome) and without (hypocapnic cerebral hypoperfusion) represent a spectrum of the same disorder.

Spectrum of chronic orthostatic intolerance without orthostatic hypotension includes postural tachycardia syndrome (POTS), with orthostatic tachycardia and hypocapnic cerebral hypoperfusion (HYCH), without orthostatic tachycardia. This study compared autonomic, cerebrovascular, and neuropathic features of POTS and HYCH. This retrospective study evaluated patients with orthostatic intolerance referred for autonomic testing. Analyzed data included surveys (Survey of Autonomic Symptoms, Compass-31, Neuropathy Total Symptom Score-6, Central Sensitization Inventory) and autonomic tests (Valsalva maneuver, deep breathing, sudomotor and tilt tests), cerebrovascular (cerebral blood flow velocity (CBFv) monitoring in the middle cerebral artery), respiratory (capnography), neuropathic (skin biopsies for assessment of small fiber neuropathy) and invasive cardiopulmonary exercise testing (iCPET). A total of 127 HYCH, 125 POTS, and 42 healthy controls were analyzed. Compared HYCH to POTS patients, there was no difference in the duration of symptoms, the prevalence of younger women, comorbidities, sensory and autonomic complaints, central sensitization syndrome, supine/standing norepinephrine levels, inflammatory markers and medical therapy except for gastrointestinal medication. Autonomic testing showed widespread but similar abnormalities in POTS and HYCH that included: reduced orthostatic CBFv and end-tidal CO2, preload failure (assessed in 16/19 POTS/HYCH), mild autonomic failure, and frequent small fiber neuropathy. HYCH and POTS are syndromes of orthostatic intolerance with cerebral hypoperfusion associated with reduced orthostatic cerebral blood flow, hypocapnia, mild autonomic failure and small fiber neuropathy of a similar degree and distribution; except for tachycardia in POTS. Similarities in peripheral domain abnormalities that affect heart rate suggest that orthostatic tachycardia in POTS is driven by the central nervous system overcompensation of orthostatic challenge. These findings provide additional evidence that HYCH and POTS represent a spectrum of the same disorder. Reduced orthostatic cerebral blood flow is a key unifying feature of HYCH and POTS.

The influence of sex on the treatment of postural tachycardia syndrome in children.

There are differences in postural tachycardia syndrome (POTS) incidence and manifestations in children between the sexes. However, there is limited evidence on how the gender affects the prognosis of POTS in children. This study is aimed at exploring the differences between the sexes regarding the prognosis of children with POTS. A retrospective study was conducted on children (n = 53; aged 6-14 years) who were diagnosed with POTS. All the POTS patients were given health education and autonomic function training, their water and salt intake was increased (oral rehydration salt III, 250 mL, Bid), and they were administered oral metoprolol (1 mg/kg per day) for 3 months. The prognosis was defined by the head-up tilt test results after treatment. It was observed that male and female children exhibited different trends in POTS prognosis. Further, the sex showed a stable independent effect on prognostic in children with POTS. To elaborate, females had a 503% increased risk of poor prognosis compared to males. We hence hypothesize that there is an association between the sex and the POTS prognosis in children. Female patients have a significantly higher risk of poor prognosis compared to males. A slight increase in the dose of oral rehydration salt could help lower the risk of poor prognosis in children with POTS. A higher absorption of total metoprolol, lower local concentrations, and slower metabolic excretion are documented in research in female POTS patients during treatment. It is recommended that the optimal dose of metoprolol should be lowered in female children undergoing treatment, to limit the risk of poor prognosis.

Hypocapnic Orthostatic Intolerance with (POTS) and without (HYCH) Tachycardia Represent a Spectrum of the Same Disorder (S43.003)

<h3>Objective:</h3> To compare postural tachycardia syndrome (POTS) with hypocapnic cerebral hypoperfusion (HYCH). <h3>Background:</h3> Several chronic orthostatic intolerance syndromes are associated with hypocapnia-driven cerebral hypoperfusion. Common syndromes are POTS where orthostatic tachycardia is present, and HYCH, where orthostatic tachycardia is absent. <h3>Design/Methods:</h3> This retrospective study evaluated consecutive patients with POTS and HYCH. Analyzed data included surveys (autonomic and sensory), autonomic (Valsalva maneuver, deep breathing, sudomotor and tilt tests), cerebrovascular (cerebral blood flow velocity (CBFv) monitoring in the middle cerebral artery), respiratory (capnography), neuropathic (skin biopsies for assessment of small fibers) testing and metabolic/inflammatory/autoimmune markers. <h3>Results:</h3> Eighty-one POTS and seventy-two HYCH patients were evaluated and they were compared to 25 healthy controls. POTS and HYCH patients had similar ages, gender, disease duration, and survey scores. Orthostatic CBFv was reduced in HYCH (−22.1±9.4%) and POTS (−23.3±12.0%) compared to controls (−4.4±7.1%,p&lt;0.001). Orthostatic end-tidal CO₂ was reduced in HYCH (27.9±5.6 mmHg) and POTS (27.1±5.6 mmHg) compared to controls (35.3±4.8 mmHg, p&lt;0.001). Orthostatic heart rate was higher in POTS (117±19.3 BPM) compared to HYCH (88.5±15.0 BPM, p&lt;0.001). Mild autonomic failure was present in 91.7% of HYCH and 82.7% of POTS patients. Compared HYCH with POTS, there was no significant difference in the following QASAT scores: sympathetic sudomotor (1.7±1.6/1.3±1.8, HYCH/POTS), parasympathetic cardiovagal (0.4±0.7/0.3±0.6), sympathetic adrenergic (1.2±0.9/1.1±1.0), epidermal fiber density (EFD, 1.8±2.1/1.9/2.4) and sweat gland fiber density (SGF, 1.4±2.0/1.5±2.3). EFD/SGF was abnormal in 63.4%/41.5% of HYCH and 55.8%/43.1% of POTS. Autoimmune markers were positive in 75% of HYCH and 81.5% of POTS. There was no significant difference in supine and orthostatic norepinephrine in both conditions. <h3>Conclusions:</h3> POTS and HYCH have similar abnormalities on subjective and objective measures except for the presence of tachycardia in POTS. Considering that the POTS-grade orthostatic tachycardia (≥30 BPM) can be seen in healthy subjects, these results suggest that HYCH and POTS represent a spectrum of the same disorder. <b>Disclosure:</b> Dr. Novak has received personal compensation for serving as an employee of Dysimmune Disease Foundation. Dr. Novak has stock in Pfeizer. Dr. Novak has stock in Moderna. Dr. Novak has stock in Novavax. Dr. Novak has stock in Editas Medicine. Dr. Novak has stock in Prothena. Dr. Novak has received publishing royalties from a publication relating to health care. Miss Marciano has nothing to disclose.

Abstract 054: Altered Valsalva Maneuver Hemodynamics In Postural Tachycardia Syndrome

Postural Tachycardia Syndrome (POTS) is often associated to subtle cardiovascular autonomic alterations. Valsalva maneuver (VM) is commonly used in clinical settings to assess autonomic functions. Specific hemodynamic responses during VM phases can support POTS diagnosis and can provide pathophysiological characterization.We hypothesize that POTS patients present differences in VM morphology with respect to healthy controls. We conducted a case-control study enrolling subjects with prior clinical diagnosis of POTS and controls. ECG and finger blood pressure were continuously recorded during an against-resistance expiratory effort, producing a 30-mmHg straining pressure for 15 seconds in supine. Hemodynamic parameters were computed in absolute terms at baseline, early (VM2e) and late (VM2l) phase 2, phase 3 (VM3) and phase 4 (VM4) and in inter-phase changes. We studied 13 POTS and 12 controls matched for age (28 ±2 vs 31 ±3 ; p=0.98) and BMI (24.2 ± 1.0 vs 23.2 ± 0.8; p=0.46). Mean HR was increased at baseline (80 ±4 vs 69 ±3 bpm; p&lt;0.05). POTS had higher absolute SBP during VM3 (90 ±4 vs 76 ±4 mmHg; p&lt;0.05) and VM4 (124 ±5 vs 112 ±3 mmHg; p&lt;0.05). Figure shows higher HR increment (22 ± 2 vs 12 ±4 bpm; p&lt;0.05) during VM2e and greater SBP rise (17 ± 4 vs 10 ±3 mmHg; p&lt;0.05) in VM2l compared to controls. VM4 SBP overshoot increase was similar (17 ± 3 vs 14 ± 3 mmHg; p=0.36). POTS have higher SBP rise during VM2l and higher VM2e HR increase. These results suggest that VM analysis can aid clinical diagnosis and that maximal baroreceptor unloading creates higher tachycardic response and vasoconstriction in POTS.

Comparison of cortisol levels in patients with vasovagal syncope and postural tachycardia syndrome.

ABSTRACTObjectives:To compare the levels of cortisol in patients of vasovagal syncope (VVS) and postural tachycardia syndrome (POTS).Methods:A cross-sectional analytical study was conducted at Islamic International Medical College, Rawalpindi and Electrophysiology Department at (AFIC). This study included 80 subjects, comprising of 35 patients in each group of vasovagal syncope and postural tachycardia syndrome and 10 healthy subjects. Patients with complaint of syncope was evaluated for vasovagal syncope and postural tachycardia syndrome using Head Up Tilt Test (HUTT. Blood samples of all the participants were taken and serum cortisol was analyzed using ELISA method. Results were analyzed on SPSS Statistics 21 using ANOVA with a p value of ≤0.05 regarded as significant.Results:Hormonal analysis shows that cortisol levels in the vasovagal, postural tachycardia syndrome and in control group was 153±16.7pg/ml, 160.17±pg/ml, and 69.65± 5.8pg/ml respectively. Cortisol levels were significantly higher in both vasovagal and POTS groups as compared to controls with a p-value of 0.04 and 0.023 respectively. However, there was no significant difference between vasovagal and POTS patients with p value 0.570.Conclusion:It is concluded from the study that cortisol responses of VVS and POTS were positive.

Sensory changes in postural tachycardia syndrome compared to chronic migraine

Postural tachycardia syndrome (PoTS) and migraine frequently present together in clinical practice. Up to 90% of PoTS patients report headaches of some kind, with migrainous headaches as the most widely recognized primary headache in this cohort. Given this comorbidity, pathophysiological interaction is possible, which could identify key features of disease pathophysiology and targeted treatment interventions. We hypothesized that migrainous and non-migrainous PoTS subjects would show features of central sensitization, including allodynia and photophobia.

Comparison of the Active Sitting Test and Head-Up Tilt Test for Diagnosis of Postural Tachycardia Syndrome in Children and Adolescents.

Objectives: We aimed to compare the hemodynamic responses to the active sitting test with the passive head-up tilt test (HUTT) in children and adolescents with postural tachycardia syndrome (POTS). We hypothesized that sitting tachycardia was also present in POTS patients during sitting.Materials and methods: We tested 30 POTS patients and 31 control subjects (mean age = 12 years, range = 9–16 years) who underwent both active sitting test and HUTT successively. We measured the heart rate (HR) and blood pressure (BP) during each test.Results: For both POTS patients and control subjects, the HUTT produced significantly larger HR and BP increases from 3 to 10 min of postural change than did the sitting test. Moreover, POTS patients with excessive orthostatic tachycardia during the HUTT also had significantly larger increases in HR at all test intervals during the sitting test than did the control subjects. A maximum increase in HR ≥ 22 bpm within 10 min of the sitting test was likely suggested to predict orthostatic tachycardia, yielding a sensitivity and specificity of 83.3 and 83.9%, respectively. Only six of 30 POTS patients (20%) reached the 40-bpm criterion during the sitting test, and no one complained of sitting intolerance symptoms.Conclusions: We have shown that POTS patients also have sitting tachycardia when changing from a supine position to a sitting position. We believe that the active sitting test is a reasonable alternative maneuver in assessing POTS in population groups that cannot tolerate the standing test or HUTT.

Abstract P196: Exacerbation Of Postural Tachycardia Syndrome After An Oral Glucose Challenge: Role Of Incretins

Postural Tachycardia Syndrome (POTS) is characterized by excessive upright tachycardia and disabling pre-syncopal symptoms, which are exacerbated after consuming a high-carbohydrate meal. The purpose of this study is to investigate the effect of oral glucose on orthostatic hemodynamic changes and gastrointestinal hormone secretion in POTS. We studied 12 women with POTS and 13 age-matched controls, all subjects received 75-gr oral glucose and 20 mg/kg acetaminophen for nutrient absorption measurement. Hemodynamic, GI hormone secretion and acetaminophen levels were measured at different time-points up to 120-min post-ingestion and while supine and standing. POTS patients had significant upright tachycardia ( delta HR: 48.7 ± 11.2 vs. 23.3 ± 8.1 bpm, P=0.012) and norepinephrine levels (835.2 ± 368.4 vs. 356.9 ± 156.7 pg/mL, P= 0.004). After oral glucose, upright HR significantly increased in POTS (92±15.5 vs. 112± 26 bpm, P=0.002) with a concomitant decline in upright stroke volume (P=0.027); total peripheral resistance, blood pressure and cardiac output remained unaltered. Acetaminophen rate of appearance was similar between groups (P=0.707). POTS patients had increased secretion of C-peptide (P=0.001), Glucose Dependent Insulinotropic Peptide (GIP) (P=0.001), peptide YY (P=0.016) and pancreatic polypeptide (P=0.04), but not GLP-1 (p=0.658) or Glucagon (P=0.836). Only GIP had a time-dependent association with the worsening upright tachycardia and SV fall, figure. Conclusions: Oral glucose exacerbated upright tachycardia in POTS, which was associated with a decline in SV; these changes occurred while GIP, a splanchnic vasodilator, is being maximally secreted.

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. Serum-derived immunoglobulin G (IgG) from antibody-positive POTS patients induced a dose-dependent activation of M2R, which was blocked by the muscarinic antagonist atropine. Moreover, antibody-positive POTS IgG decreased the responsiveness to oxotremorine, an orthosteric muscarinic agonist, indicating an indirect inhibitory effect. These data suggest that M2R autoantibodies may contribute to the pathophysiology of POTS by increasing the normal vagal withdrawal during upright posture through its negative allosteric modulation of M2R activity. M2 muscarinic receptor-activating autoantibodies are present in a subgroup of patients with POTS and act as a negative allosteric modulator of the orthosteric ligand response.

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

BackgroundHigh 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. ObjectivesThis 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. MethodsA 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. Supine and standing heart rate, blood pressure, serum aldosterone, plasma renin activity, blood volume, and plasma norepinephrine and epinephrine were measured. ResultsIn POTS, the HS diet reduced upright heart rate and Δ heart rate compared with the LS diet. Total blood volume and PV increased, and standing norepinephrine decreased with the HS compared with the LS diet. However, upright heart rate, Δ heart rate, and upright norepinephrine remained higher in POTS than in HC on the HS diet (median 117 beats/min [interquartile range: 98 to 121 beats/min], 46 beats/min [interquartile range: 32 to 55 beats/min], and 753 pg/ml [interquartile range: 498 to 919 pg/ml] in POTS vs. 85 beats/min [interquartile range: 77 to 95 beats/min], 19 beats/min [interquartile range: 11 to 32 beats/min], and 387 pg/ml [interquartile range: 312 to 433 pg/ml] in HC, respectively), despite no difference in the measured PV. ConclusionsIn POTS patients, high dietary sodium intake compared with low dietary sodium intake increases plasma volume, lowers standing plasma norepinephrine, and decreases Δ heart rate. (Dietary Salt in Postural Tachycardia Syndrome; NCT01547117)

Observational case series describing features of cardiopulmonary exercise testing in Postural Tachycardia Syndrome (PoTS).

Postural Tachycardia Syndrome (PoTS) is a chronic condition often affecting multiple systems with varied presenting symptoms. Diagnosis is made by demonstrating cardiovascular criteria on standing along with clinical assessment. Cardiopulmonary exercise testing has been used to demonstrate and characterise the physiological response to exercise and the severity of the syndrome. Previous studies on exercise testing in these patients have focussed on cardiovascular changes alone. This series characterises the integrated cardiac and respiratory response to exercise seen with cardiopulmonary exercise testing. Our main findings show that peak oxygen uptake, work done and peak heart rate are significantly reduced from their respective predicted values in PoTS patients. However, despite this, most patients demonstrated a normal exercise capacity. Features of ventilatory inefficiency were also seen which suggest exercise capacity in these patients may be limited more by impaired ventilatory control such as dysfunctional breathing during exercise rather than by cardiovascular issues.

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

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. POTS patients were recruited from the Dysautonomia International Annual Patient and Caregiver Conference. VVS patient data came from those enrolled in the Second Prevention of Syncope Trial. Participants aged ≥ 18years (177 POTS and 72 VVS) completed the RAND 36-Item Health Survey, a generic and coherent health-related quality of life survey. POTS patients reported reduced HRQoL compared to VVS patients in physical functioning (42.5 ± 1.7 vs. 76.5 ± 2.9, p < 0.001), role limitations due to physical health (11.4 ± 1.9 vs. 33.0 ± 5.0, p < 0.001), energy and fatigue (27.2 ± 1.3 vs. 50.7 ± 2.6, p < 0.001), social functioning (45.2 ± 1.8 vs. 71.2 ± 2.9, p < 0.001), pain (48.8 ± 1.9 vs. 67.7 ± 2.9, p < 0.001), and general health (31.2 ± 1.5 vs. 60.5 ± 2.6, p < 0.001) domains. Scores did not differ significantly in the role limitations due to emotional health (p = 0.052) and emotional well-being (p = 0.271) domains. Physical and general health composite scores were lower in the POTS population, while mental health composite scores were not different. Differences in HRQoL exist between these patient populations. POTS patients report lower scores in physical and general health domains than VVS patients, but emotional health domains do not differ significantly. Targeting physical functioning in these patients may help improve quality of life.

Sex differences in the diagnosis of postural tachycardia syndrome: insights from a cross-sectional community based survey

Postural tachycardia syndrome (POTS) is a common form of orthostatic intolerance that primarily affects females of child-bearing age. We compared the diagnostic journey between female and male POTS patients.

Decreased Stroke Volume and Venous Return in School Children with Postural Tachycardia Syndrome.

In postural tachycardia syndrome (POTS), a subtype of orthostatic intolerance, the changes in hemodynamics due to postural changes are poorly understood. We speculated that inappropriate venous return, which may occur in the upright position in patients with school-aged POTS, could be detected by echocardiography. Our prospective study was conducted with 100 POTS patients (45 boys and 55 girls), aged 13.1 ± 1.5 years and 52 age- and sex-matched healthy subjects (control). Echocardiography was performed in the supine and sitting positions. Cardiac parameters [stroke volume index, cardiac index, heart rate, and the maximum inferior vena cava diameter (max IVC)] were evaluated in addition to pulse pressure. Unlike the control subjects, POTS patients demonstrated decreased stroke volume index (P = 0.02) and max IVC (P < 0.01) irrespective of posture. The rates of max IVC change did not differ between control and POTS groups. The enrolled POTS patients were divided into two subgroups [dilatation (n = 57) and contraction (n = 43)] based on whether the change rate of max IVC was less than zero or not. The contraction group showed a significantly higher heart rate than the dilatation group with respect to posture (P = 0.03), indicating the poor response of peripheral vessels in the lower limbs only in the contraction group. In conclusion, echocardiographic assessment detected decreased stroke volume and venous return in POTS. The changes in max IVC in response to postural changes may indicate an underlying pathophysiology in POTS.

S0481 Overlap in Gastrointestinal Manifestations Among Small Fiber Neuropathy, Postural Tachycardia Syndrome, Ehlers-Danlos Syndrome, and Mitochondrial Disease Adult Patients

INTRODUCTION: Small fiber neuropathy (SFN) is characterized by damage to thinly myelinated A-delta and/or unmyelinated C-fibers in the peripheral nervous system; these fibers regulate automatic functions, including digestion. SFN is known to cause abnormalities in the neural control of smooth muscle, however, the gastrointestinal (GI) manifestations of these abnormalities have not been reported. Structural and functional small fiber abnormalities are common in patients with postural tachycardia syndrome (POTS), Ehlers-Danlos syndrome (EDS), and mitochondrial disease (MD), and clinicians frequently see overlapping GI manifestations in these patient populations. METHODS: Among adult (ages 18–74) patients, we examined the relative GI manifestations of SFN, POTS, EDS, and MD to determine whether these diseases have unique GI phenotypes. We conducted a retrospective cohort analysis of SFN (N = 506, 75.5% female), POTS (N = 255, 90.1% female), EDS (N = 413, 87.1% female), and MD (N = 175, 68.0% female) patients reporting GI symptoms presenting to an academic medical center between 2004 and 2019. Patient diagnoses were categorized by symptom clusters: esophageal, gastric, lower GI, and abdominal pain with examination of the frequency of individual diagnoses as well. RESULTS: Overall, GI diagnoses were common and most frequent in MD (92.0%) relative to POTS (86.7%), EDS (81.1%), and SFN (70.4%). Abdominal pain was common among all conditions, led by MD (69.1%) and POTS (61.2%) (Table 1). There were significant differences in symptom distribution across all disease groups (Figure 1): there was a relatively-even distribution of diagnoses in SFN, gastric diagnoses were most common in POTS (65.1%), esophageal diagnoses most common in EDS (43.8%), and esophageal diagnoses (70.9%) and lower GI diagnoses (69.1%) most common in MD. Among individual diagnoses, >50% of patients with POTS experienced nausea/vomiting, constipation, and abdominal pain and >50% of MD patients experienced GERD, nausea/vomiting, constipation, and abdominal pain. CONCLUSION: Despite similar demographics and chronic GI complaints, GI phenotypes differed significantly between patients with SFN, POTS, EDS, and MD. Patients with MD and POTS were most likely to present with GI complaints, with abdominal pain the most common manifestation among all of the disorders.Table 1.: Characteristics of adults patients diagnosed with SFN, POTS, EDS, or MD. Note. SFN = small fiber neuropathy; POTS = postural tachycardia syndrome; EDS = Ehlers-Danlos syndrome; MD = mitochondrial disease. 1. Continuous variables analyzed with ANOVA and categorical variables analyzed with Chi-Square TestFigure 1.: Overall prevalence of GI diagnoses in SFN, POTS, EDS, and MD patients. Note. Patients may have more than one diagnosis.

Treatment Updates in Postural Tachycardia Syndrome

Postural tachycardia syndrome is a common condition characterized by the presence of orthostatic intolerance in conjunction with excessive postural tachycardia. This review will focus on treatment updates in postural tachycardia syndrome and will include a discussion of rehabilitative, vasopressor, heart rate modulation, volume expansion, and immunomodulatory treatment strategies. A recent study added to existing literature the benefits of exercise retraining in postural tachycardia syndrome (POTS) patients who were able to successfully complete a 3-month exercise regimen. Another recent, novel study reported the benefits of respiratory retraining in POTS patients reporting breathlessness. The benefits of volume expansion in the treatment of POTS were strengthened by 2 recent studies, including a study demonstrating the value of oral rehydration salts in improving hemodynamic parameters in POTS patients and another prospective study demonstrating the value of IV saline infusions in POTS patients. A recent meta-analysis reviewed the efficacy of ivabradine in the treatment of POTS, while another systematic review and meta-analysis reviewed the benefits of metoprolol in the treatment of childhood and adolescent POTS. Also included in this review is that of a large clinical trial comparing propranolol and bisoprolol alone and with pyridostigmine, demonstrating efficacy of beta blockers and an absence of any clear additive benefit with pyridostigmine. A retrospective review of droxidopa in a large POTS cohort reported improvement in only 27% of POTS patients. Recent approaches to the pharmacologic and non-pharmacologic treatment of cognitive dysfunction and fatigue in POTS patients were reviewed. Finally, a retrospective series of the benefits of intravenous immunoglobulin in POTS suspected of being autoimmune is reviewed. The treatment of postural tachycardia syndrome is complex and nuanced, requiring a combination of lifestyle and pharmacologic treatments in most patients. This review provides treatment updates for this enigmatic condition.

Postural Tachycardia Syndrome in Children and Adolescents: Pathophysiology and Clinical Management.

Postural tachycardia syndrome (POTS), characterized by chronic (≥6 months) orthostatic intolerance symptoms with a sustained and excessive heart rate increase while standing without postural hypotension, is common in children and adolescents. Despite the unclear pathogenesis of POTS, the present opinion is that POTS is a heterogeneous and multifactorial disorder that includes altered central blood volume, abnormal autonomic reflexes, “hyperadrenergic” status, damaged skeletal muscle pump activity, abnormal local vascular tension and vasoactive factor release, mast cell activation, iron insufficiency, and autoimmune dysfunction. A number of pediatric POTS patients are affected by more than one of these pathophysiological mechanisms. Therefore, individualized treatment strategies are initiated in the management of POTS, including basal non-pharmacological approaches (e.g., health education, the avoidance of triggers, exercise, or supplementation with water and salt) and special pharmacological therapies (e.g., oral rehydration salts, midodrine hydrochloride, and metoprolol). As such, the recent progress in the pathogenesis, management strategies, and therapeutic response predictors of pediatric POTS are reviewed here.

The preponderance of initial orthostatic hypotension in postural tachycardia syndrome.

Reduced systolic/diastolic blood pressure (BP) by >40/20 mmHg defines initial orthostatic hypotension (IOH). Rapid resolution of hypotension and lightheadedness follows, but tachycardia may be prolonged. We aimed to examine IOH in controls and patients with postural tachycardia syndrome (POTS) using indices of spontaneous fluctuations of heart rate (HR) and systolic BP as measures of cardiac baroreflex differences. We recruited otherwise healthy IOH patients without POTS (n = 20, 16 ± 3 yr), healthy volunteers (n = 32, 17 ± 3 yr), and POTS patients (n = 39, 17 ± 4 yr). Subjects were instrumented for electrocardiography and beat-to-beat BP. After 10 min supine, subjects stood for 5 min. Following supine recovery, subjects underwent 70° head-up tilt for 10 min to test for POTS. BP, HR, and time, referenced to standing, were measured at events during standing: minimum BP, BP recovery, peak HR, HR minimum, and steady state. Baseline HR and BP were higher in POTS compared with healthy groups. IOH occurred in 13% of controls and 51% of POTS patients. The BP minimum was lower in POTS. Parasympathetic modulation of cardiac baroreflex was decreased in all POTS and control-IOH subjects. Sympathetic indices were increased. Events following BP minimum occurred progressively later in all POTS and control-IOH subjects compared with non-IOH controls. IOH is more frequent in POTS than in controls with a lower minimum BP. POTS has markedly reduced heart rate variability and baroreflex, indicating reduced HR buffering of BP. POTS-IOH and control-IOH subjects had similar peak HR despite decreased minimum BP in POTS. IOH data indicate modest parasympathetic and cardiovagal baroreflex deficits in control-IOH subjects. Parasympathetic deficits are more severe in all POTS patients.NEW & NOTEWORTHY Significant initial orthostatic hypotension (IOH) occurs in ~50% of postural tachycardia syndrome (POTS) patients and 13% of controls. Heart rate and blood pressure recovery are prolonged in IOH sustaining lightheadedness; IOH is more prevalent and severe in POTS. Altered cerebral blood flow and cardiorespiratory regulation are more prevalent in POTS. Altered heart rate variability and baroreflex gain may cause nearly instantaneous lightheadedness in POTS. IOH alone fails to confer a strong probability of POTS.

Splanchnic Venous Compression Enhances the Effects of ß-Blockade in the Treatment of Postural Tachycardia Syndrome.

BackgroundSplanchnic venous pooling induced by upright posture triggers a compensatory increase in heart rate (HR), a response that is exaggerated in patients with postural tachycardia syndrome. To assess whether abdominal compression attenuates orthostatic tachycardia and improves symptoms, 18 postural tachycardia syndrome patients (32±2 years) were randomized to receive either abdominal compression (40 mm Hg applied with an inflatable binder ≈2 minutes before standing) or propranolol (20 mg) in a placebo‐controlled, crossover study.Methods and ResultsSystolic blood pressure, HR, and symptoms were assessed while seated and standing, before and 2 hours postdrug. As expected, propranolol decreased standing HR compared with placebo (81±2 versus 98±4 beats per minute; P<0.001) and was associated with lower standing systolic blood pressure (93±2 versus 100±2 mm Hg for placebo; P=0.002). Compression had no effect on standing HR (96±4 beats per minute) but increased standing systolic blood pressure compared with placebo and propranolol (106±2 mm Hg; P<0.01). Neither propranolol nor compression improved symptoms compared with placebo. In 16 patients we compared the combination of abdominal compression and propranolol with propranolol alone. The combination had no additional effect on standing HR (81±2 beats per minute for both interventions) but prevented the decrease in standing systolic blood pressure produced by propranolol (98±2 versus 93±2 mm Hg for propranolol; P=0.029), and significantly improved total symptom burden (−6±2 versus −1±2 for propranolol; P=0.041).ConclusionsSplanchnic venous compression alone did not improve HR or symptoms but prevented the blood pressure decrease produced by propranolol. The combination was more effective in improving symptoms than either alone. Splanchnic venous compression can be a useful adjuvant therapy to propranolol in postural tachycardia syndrome.Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT00262470.

Psychological distress among postural tachycardia syndrome patients in the Fennell Crisis phase

ABSTRACT Postural tachycardia syndrome (POTS) is a chronic illness that disrupts the autonomic nervous system and decreases quality of life. The Fennell Phase Inventory is a developmental instrument that divides the experience of chronic illness into four phases: Crisis, Stabilization, Resolution, and Integration. This study applied the Fennell Phase Inventory to POTS patients. Methods: 360 women with a primary diagnosis of POTS completed the World Health Organization Quality of Life BREF scale, Fennell Phase Inventory, Beck Depression Inventory-II, Beck Hopelessness Scale, Interpersonal Needs Questionnaire-15, Ten Item Personality Inventory, and the Suicide Behaviors Questionnaire-Revised. Results: Among these POTS patients, 35.8% were in the Fennell Crisis phase, 14.7% Stabilization, 46.7% Resolution, and 2.8% were in the Integration phase. One-way analyses of variance showed significant differences between the four Fennell groups on Overall Quality of Life, Physical Health, Psychological Health, Social Health, Depression, Hopelessness, Thwarted Belongingness, and Perceived Burdensomeness. Post hoc tests revealed that the Crisis group was more distressed than the other three groups on nearly every symptom scale (p < .05), but that the Stabilization, Resolution, and Integration groups were statistically similar to each other. Conclusions: Nearly one-third of participants were in Crisis, a phase characterized by lower quality of life and significant psychological distress. Recognizing and addressing the concerns of POTS patients according to their current chronic illness phase may help decrease the overall trauma experienced by the patient and improve compliance to proposed treatment regimens.