Pediatric Postural Tachycardia Syndrome Research Articles

Baseline Corrected QT Interval Dispersion Is Useful to Predict Effectiveness of Metoprolol on Pediatric Postural Tachycardia Syndrome.

ObjectivesThe study was designed to explore the role of baseline-corrected QT interval dispersion (QTcd) in predicting the effectiveness of metoprolol on pediatric postural tachycardia syndrome (POTS).MethodsThere were two groups in the study, the discovery group and the validation group. The children with POTS in the discovery group were treated with oral metoprolol, with the completed necessary medical records, head-up tilt test (HUTT), blood chemistry, and 12-lead ECG before treatment at the pediatrics of Peking University First Hospital, China. According to whether the symptom score (SS) was reduced by more than 2 points after administration with oral metoprolol as compared with that before treatment, the children with POTS were separated into responders and non-responders. The demographic characteristics, hemodynamic indicators, and the QTcd of the two groups were compared, and the estimate of the baseline QTcd in predicting the treatment response to metoprolol was tested through a receiver operating characteristic (ROC) analysis. Other 24 children suffering from POTS who were, administrated with metoprolol at the pediatrics of Peking University First Hospital were included in the validation group. The sensitivity, specificity, and accuracy of the baseline QTcd in the prediction of the effectiveness of metoprolol on POTS were validated in children.ResultsThe pre-treatment baseline QTcd in responders treated with metoprolol was longer than that of the non-responders in the discovery group [(66.3 ± 20.3) ms vs. (45.7 ± 19.9) ms, p = 0.001]. The baseline QTcd was negatively correlated with SS after metoprolol treatment (r = −0.406, p = 0.003). The cut-off value of baseline QTcd for the prediction of the effectiveness of metoprolol on pediatric POTS was 47.9 ms, yielding a sensitivity of 78.9% and a specificity of 83.3%, respectively. The validation group showed that the sensitivity, specificity, and accuracy of the baseline QTcd ≥ 47.9 ms before treatment for estimating the effectiveness of metoprolol on POTS in children were 73.7, 80.0, and 75.0%, respectively.ConclusionBaseline QTcd is effective for predicting the effectiveness of metoprolol on pediatric POTS.

Impact of Comorbidities on the Prognosis of Pediatric Postural Tachycardia Syndrome.

ObjectiveTo investigate the influence of comorbidities on the prognosis of pediatric postural tachycardia syndrome (POTS).MethodsIn this retrospective cohort study, 275 children with POTS admitted to the Department of Pediatrics at Peking University First Hospital were recruited from 2016 to 2019 and followed up. The participants were divided into simple POTS (S-POTS, n=156 cases) and POTS with comorbidities (Co-POTS, n=119 cases) groups according to whether they were complicated with comorbidities. A Cox regression analysis was used to identify the prognostic risk factors for children with POTS, while Kaplan–Meier curves were applied to compare the cumulative symptom remission rate (CSRR) between the two groups. The rehospitalization of the children between the two groups was also compared to explore the influence of comorbidities.ResultsTwenty-one participants (7.6%) were lost during a median follow-up of 24 months. The Cox regression model showed that comorbidities and body mass index (BMI) were associated with the CSRR of the children with POTS. The CSRR of pediatric POTS alone was 1.748 times higher than that of patients with comorbidities, and the CSRR was decreased by 5.1% for each 1 kg/m2 increase in BMI. The most common comorbidity in children with POTS in this study was allergic disorders, followed by the psychological diseases. The patients in the Co-POTS group had a lower CSRR than those in the S-POTS group (log rank P=0.0001). In addition, compared with those of the S-POTS group, the total number of rehospitalizations was high (P=0.001), and the total hospital stays were long in the Co-POTS group (P<0.001).ConclusionComplicating with comorbidities, pediatric patients with POTS had lower CSRR and more rehospitalizations than those without comorbidities. More attention should be given to comorbidities when managing pediatric POTS.

Diagnostic Value of Diurnal Variability of Orthostatic Heart Rate Increment in Children and Adolescents With POTS.

Objectives: This study aims to investigate the diurnal variability of heart rate (HR) increment after standing (ΔHR) in pediatric postural tachycardia syndrome (POTS) and explore appropriate cutoff values of ΔHR at different times for the POTS diagnosis.Materials and Methods: Seventy-eight patients (9–14 years) who presented with orthostatic intolerance symptoms were enrolled. Forty-three patients were diagnosed as POTS (ΔHR ≥40 bpm), and 35 patients were assigned to the non-POTS group (ΔHR <40 bpm). Twenty-six healthy children served as the control group. All subjects completed three standing tests in the morning, afternoon, and evening. Orthostatic HR parameters were analyzed to predict the diagnosis of POTS. Additionally, 41 patients were recruited as an external validation group.Results: Orthostatic HR increments in both the POTS and non-POTS groups exhibited diurnal variability, which was markedly larger in the morning (P < 0.05), whereas it did not differ with the time of day in the control group. Among the POTS patients, 100% met the diagnostic criteria for POTS in the morning, 44.2% in the afternoon, and 27.9% in the evening. Almost half of the POTS patients (51.2%) displayed a positive result only in the morning standing test. However, in the three standing tests at different times, ΔHR from 1 to 10 min after standing and ΔHRmax were the highest in the POTS group compared with in the non-POTS and control groups (P < 0.05). Furthermore, the maximum ΔHR (ΔHRmax) and ΔHR at 5 and 10 min in the afternoon and evening standing tests yielded moderate predictive values for the POTS diagnosis. The external validation test showed that the afternoon ΔHRmax ≥30 bpm to diagnose POTS yielded sensitivity, specificity, and accuracy of 85, 71.4, and 78%, respectively, and the evening ΔHRmax ≥25 bpm yielded sensitivity, specificity, and accuracy of 85, 76.2, and 80.5%, respectively.Conclusions: The orthostatic HR increment exhibits diurnal variability in children and adolescents with POTS that may affect the diagnosis of POTS. Supplementary criteria are proposed for the POTS diagnosis based on diurnal variability.

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.

Heart Rate Variability Predicts Therapeutic Response to Metoprolol in Children With Postural Tachycardia Syndrome.

PurposeTo improve the metoprolol therapeutic effectiveness, we aimed to explore whether baseline heart rate variability (HRV) indicators before metoprolol treatment were useful for predicting its efficacy for postural tachycardia syndrome (POTS).MethodsWe recruited 45 children with POTS who received metoprolol and 17 healthy controls. All children underwent a standing test or basic head-up tilt test and 24-h dynamic electrocardiography before treatment. After 3 months of metoprolol, therapeutic responsiveness was evaluated. The usefulness of baseline HRV parameters in predicting the effectiveness of metoprolol was studied and the long-term cumulative symptom rate was analyzed.ResultsThe baseline HRV frequency domain indicators for power, ultra-low frequency, very-low frequency, low frequency (LF), high frequency (HF), and total power (TP) as well as time domain indicators were significantly lower for responders than non-responders to metoprolol; however, low-frequency normalized units and LF/HF ratio were markedly greater for responders than non-responders. On series-parallel analysis, combined baseline triangular (TR) index ≤ 33.7 and standard deviation of all normal-to-normal intervals (SDNN) index ≤ 79.0 ms as cut-off values yielded sensitivity, specificity and accuracy of 85.3, 81.8, and 84.4%, respectively, to predict therapeutic responsiveness to metoprolol. On long-term follow-up, the cumulative symptom rate was significantly higher with TR index > 33.7 and SDNN index ≤ 79.0 ms, TR index ≤ 33.7 and SDNN index > 79.0 ms or TR index > 33.7 and SDNN index > 79.0 ms than TR index ≤ 33.7 and SDNN index ≤ 79.0 ms (P < 0.05).ConclusionCombined TR index ≤ 33.7 and SDNN index ≤ 79.0 ms were useful preliminary measures to predict therapeutic response to metoprolol in pediatric POTS.

Pediatric Postural Tachycardia Syndrome (POTS): A Children's Hospital Experience (P05.205)

Objective: To describe the clinical features and diagnostic findings in children and adolescents with POTS. Background POTS involves chronic orthostatic intolerance (OI) and multi-system, non-orthostatic symptoms. Clinical description of a large series of pediatric patients with POTS is needed given the challenges in diagnosis and treatment. Design/Methods: We undertook a retrospective study and medical records review of 64 patients evaluated between April 2007-March-2011 for probable POTS by standing or head-up tilt test (HUT) or both at a Tertiary Pediatric Neurology Clinic. POTS was defined as frequent, 2 or more symptoms of OI for >3 months and a HR increment of >30 bpm or HR >120 bpm within 10 minutes of active standing or HUT, without arterial hypotension. Results: 57 patients had POTS (84% female; age 15 ± SD of 2.2 years), with mean duration of symptoms of 2 years. Mean HR increment with 33 bpm with standing and 41 with HUT, and mean maximal absolute HR was 105 with standing and 110 with HUT. Pre-existing conditions included ADHD (23%), anxiety (23%), Depression (19%), and 35% of menstruating females had menorrhagia. Antecedent infectious illness was reported in 29%. Non-orthostatic complaints included nausea (60%), abdominal pain (42%), vomiting (26%), weight loss of 1-8 kg (26%), rumination (9%), and sweating disorder (49%). Other symptoms included chronic fatigue (79%), cognitive dysfunction (44%), problems concentrating (42%), brain fog (35%), memory problems (26%), migraine (46%), chronic daily headache (30%), and sleep disorder (56%). Quantitative sudomotor axon testing was abnormal in 24 of 35 patients (67%), whereas Valsalva and deep breathing tests abnormalities were rare. Gastrointestinal diagnostic tests included abnormal GI motility with gastroparesis (11/44, (25%), gastric emptying (11/17, 67%), and HIDA scans (3/8, 37%). Conclusions: Our data demonstrate the multi-system involvement in pediatric POTS and the high prevalence of significant autonomic dysfunction and abnormal diagnostic tests. Disclosure: Dr. Hernandez has nothing to disclose. Dr. Jarjour has nothing to disclose. Dr. Jarjour has nothing to disclose.