Postural Tachycardia Syndrome Children Research Articles

Establishment and validation of a multivariate predictive model for the efficacy of oral rehydration salts in children with postural tachycardia syndrome

The therapeutic effectiveness of the empirical and unselected use of oral rehydration salts (ORS) on postural tachycardia syndrome (POTS) is not satisfactory in children. Therefore, looking for suitable predictors of the therapeutic effects of ORS before treatment is extremely necessary to implement individualised treatment for paediatric patients with POTS. A retrospective case-control analysis of 130 patients (aged 5-18 years) who suffered from POTS with a 3-month treatment of ORS was conducted. A nomogram model was developed in the training set (n=87) to predict the therapeutic response to ORS. Univariate analysis and logistic regression were applied to select the most useful predictors. ROC curves were applied to evaluate the discriminative performance of the nomogram model. The nomogram was then evaluated by calibration curves and the Hosmer-Lemeshow (H-L) test. The results were further validated using 1000 bootstrap resamples. External validation was performed in an independent validation set (n=43). Among the ten variables with significant differences between the responders and non-responders in univariate analysis, five variables were found to be independently associated factors for ORS therapeutic efficacy among POTS children in the further logistic regression, including mean corpuscular haemoglobin concentration (MCHC), mean corpuscular volume (MCV), mean arterial pressure (MAP) at the first minute of the upright position, urine specific gravity (SG), and P-wave voltage peaking ratio (PWP). The nomogram model was established in the training set (AUC 0.926 [95% CI: 0.865-0.988], yielding a sensitivity of 87.8% and a specificity of 86.8%). The calibration curves showed good agreement between the prediction of the nomogram and actual observation in both the training and validation sets. The nomogram also effectively predicted the external validation set (sensitivity 82.1%, specificity 73.3%, and accuracy 79.1%). We established a feasible and high-precision nomogram model to predict the efficacy of ORS, which would help implement individualised treatment for children with POTS. This study was supported by National High-Level Hospital Clinical Research Funding (Multi-centre Clinical Research Project of Peking University First Hospital) (2022CR59).

Circadian rhythms of blood pressure and rate pressure product in children with postural tachycardia syndrome.

To investigate circadian rhythms of blood pressure (BP) and rate pressure product (RPP) in children with postural tachycardia syndrome (POTS) by performing 24-hour ambulatory blood pressure monitoring (24-h ABPM). 103 POTS children and 84 age- and gender-matched healthy children were enrolled and they got 24-h ABPM under usual routine of diurnal activity and nocturnal sleep. Although the mean awake systolic BP (SBP), 24-h diastolic BP (DBP), awake DBP, asleep heart rate (HR) did not differ between two groups (P>0.05), the mean 24-h and asleep SBP, asleep DBP, 24-h and awake HR, 24-h, awake and asleep RPP were significantly higher in POTS children (P<0.01). Non-dipping BP was more prevalent in POTS children (67.0% vs. 46%, P<0.001). The RPP of POTS and control children showed 24-h circadian variations with peak roughly occurring approximately 2h after waking from nocturnal sleep. Compared with controls, the RPP values of POTS children were significantly higher during 2h before and 3h after waking (P<0.05). For the RPP value of 1h after waking, a cutoff value of 8995.6bpm·mmHg yielded a sensitivity of 75.8% and a specificity of 65.4% for predicting POTS. Abnormal circadian BP regulation is prevalent in POTS children. POTS children present with daily sympathetic hyperactivity, especially during nocturnal sleep and within 3h after waking. And the excessive morning surge in RPP parallels with the morning surge of orthostatic HR increments and OI symptoms.

Baroreflex Sensitivity Predicts Short-Term Outcome of Postural Tachycardia Syndrome in Children.

ObjectiveThe study was designed to examine if baroreflex sensitivity (BRS) could predict the short-term outcome of postural tachycardia syndrome (POTS) in children.MethodsSeventy-seven children subjects were included in the study. Among them, 45 children were in the POTS group and another 32 healthy children were in the control group. A ninety-day clinical follow-up was conducted and the symptom score before and after the follow-up was calculated for POTS patients by using POTS score system. Hemodynamics and continuous BRS monitoring were recorded by Finapres Medical System-FMS (FinometerPRO, FMS Company, Netherlands). According to the symptom score change during follow-up period, POTS patients were further divided into subgroup A (n = 24) with symptom score decreased by at least two points and subgroup B (n = 21) with symptom score decreased by less than two points. The predictive value of BRS in the short-term outcome of POTS in children was analyzed using receiver-operating characteristic (ROC) curve.ResultsBRS of POTS children was significantly higher than that of the healthy children (18.76±9.96 ms/mmHg vs 10±5.42 ms/mmHg, P<0.01). It was higher in subgroup B than that of subgroup A (24.7±9.9 ms/mmHg vs 13.5±6.6 ms/mmHg, P <0.01). BRS was positively correlated with HR change in POTS Group (r = 0.304, P <0.05). Area under curve (AUC) was 0.855 (95% of confidence interval 0.735–0.975), and BRS of 17.01 ms/mmHg as a cut-off value yielded the predictive sensitivity of 85.7% and specificity of 87.5%.ConclusionsBRS is a useful index to predict the short-term outcome of POTS in children.

Pathogenesis and Individualized Treatment for Postural Tachycardia Syndrome in Children.

Objective:Postural tachycardia syndrome (POTS) is one of the major causes of orthostatic intolerance in children. We systematically reviewed the pathogenesis and the progress of individualized treatment for POTS in children.Data Sources:The data analyzed in this review are mainly from articles included in PubMed and EMBASE.Study Selection:The original articles and critical reviews about POTS were selected for this review.Results:Studies have shown that POTS might be related to several factors including hypovolemia, high catecholamine status, abnormal local vascular tension, and decreased skeletal muscle pump activity. In addition to exercise training, the first-line treatments mainly include oral rehydration salts, beta-adrenoreceptor blockers, and alpha-adrenoreceptor agonists. However, reports about the effectiveness of various treatments are diverse. By analyzing the patient's physiological indexes and biomarkers before the treatment, the efficacy of medication could be well predicted.Conclusions:The pathogenesis of POTS is multifactorial, including hypovolemia, abnormal catecholamine state, and vascular dysfunction. Biomarker-directed individualized treatment is an important strategy for the management of POTS children.

Predictive value of upright blood pressure change for long-term prognosis of children with postural tachycardia syndrome treated with midodrine hydrochloride

To explore the predictive value of upright blood pressure change for long-term prognosis of children with postural tachycardia syndrome (POTS) treated with midodrine hydrochloride. A total of 90 children (male 41, female 49) were enrolled in this study. Their mean age was (11.8±2.7) years. They were diagnosed as POTS in Peking University First Hospital from 2005 to 2011. According to the upright change of blood pressure at the first visit, they were divided into two groups, effective group (n=55) and ineffective group(n=35). The follow-up time was 53-130 months. The orthostatic intolerance symptom score and symptom free survival rate were compared between the two groups. The change of systolic blood pressure and of diastolic blood pressure was lower in effective group than those in ineffective group (0(-6, 0) mmHg (1 mmHg=0.133 kPa) vs. 9(6, 11) mmHg, Z=-8.303, P<0.01; 0(0, 5) mmHg vs. 11(10, 16) mmHg, Z=-7.058, P<0.01). Two groups had no significant difference in symptom scores before treatment((4.8±0.9) points vs. (5.0±0.8) points, t=-0.53, P=0.595), while symptom scores were lower in effective group than that in ineffective group((1.3±0.9) points vs. (4.7±0.9) points, t=-15.60, P<0.01 ). The symptom free survival rate was higher in effective group than that in ineffective group (48/55(87.3%) vs. 23/35(65.7%), χ(2)=5.969, P<0.01). The upright change of blood pressure has a good predictive value on the long-term survival of POTS children treated with midodrine hydrochloride.

Relationship between 24-hour urinary sodium and renin-angiotensin-aldosterone system in children with postural tachycardia syndrome

To analyze the relationship between 24 hours urinary sodium and renin-angiotensin-aldosterone system (RAAS) in children with postural tachycardia syndrome (POTS) and to explore low blood volume related pathogenesis of POTS. A total of 39 POTS children who were at the clinic or admitted to the Department of Pediatrics, Peking University First Hospital from June 2012 to February 2013 and 21 healthy children (control group) were enrolled, level of RAAS in plasma, 24-hour urinary sodium and plasma sodium were detected, respectively. Baseline data, levels of RAAS and hemodynamic parameters were compared between POTS and control group, as well as groups with different 24-hour urinary sodium levels of POTS. The angiotensin II levels of POTS children were significantly higher than that of control group ((105 ± 50) vs (84 ± 28) ng/L, P = 0.041), while no statistical significance was found in plasma renin and aldosterone (P > 0.05). Pearson correlation analysis showed that 24-hour urinary sodium and angiotensin II in children with POTS was negatively correlated (r = -0.536, P < 0.001). Angiotensin II, symptom score, upright heart rate and changes of heart rate were significantly higher in urinary sodium < 124 mmol/24 h group than that in urinary sodium ≥ 124 mmol/24 h group (P < 0.05). The regulating function disorder of RAAS may involve in the pathogenesis of POTS and cause sustained low blood volume in patients with POTS.

Total Peripheral Vascular Resistance, Cardiac Output, and Plasma C-Type Natriuretic Peptide Level in Children with Postural Tachycardia Syndrome

To investigate the total peripheral vascular resistance (TPVR), cardiac output (CO), and plasma C-type natriuretic peptide (CNP) levels in children with postural tachycardia syndrome (POTS) during supine, upright, and return to supine. Twenty-nine children with POTS, aged 12 ± 3 years, were recruited, and 32 healthy children, aged 11 ± 2 years, served as controls. Heart rate (HR), blood pressure, TPVR, and CO were continuously monitored with Finapres Medical System, and plasma CNP levels were detected with Sandwich immunoluminescence assay. In children with POTS, upright TPVR and CO were significantly lower than those in supine position, and they rose again when they returned to supine position. However, in healthy control patients, both TPVR and CO did not change during supine, upright, and supine again positions. Also, in the supine position, there was no significant difference in TPVR and CO between POTS children and control subjects (P > .05). When upright, however, TPVR and CO in children with POTS were significantly lower than those of controls. Plasma CNP levels were significantly greater in children with POTS than that of controls (32.8 ± 9.7 vs 24.2 ± 8.4 [pg/mL], P < .01), and symptom scores and ΔHR positively correlated with plasma CNP levels in children with POTS (symptom scores: r = 0.490, P < .01; ΔHR: r = 0.508, P < .001), but CO negatively correlated with plasma CNP levels (r = -0.446, P < .01). Reduced TPVR and CO associated with the elevated plasma CNP might be involved in the pathogenesis of POTS.

Plasma C-type natriuretic peptide as a predictor for therapeutic response to metoprolol in children with postural tachycardia syndrome.

POTS is a global public-health disease, but predictor for therapeutic response to metoprolol in children with POTS is lacking. This study was designed to investigate predictive value of plasma C-type natriuretic peptide (CNP) in the therapeutic efficacy of metoprolol on postural tachycardia syndrome (POTS) in children. Totally 34 children with POTS and 27 healthy children were included in the study. The head-up test or head-up tilt test was used to check heart rate and blood pressure from supine to upright in subjects. A double antibody (competitive) sandwich immunoluminometric assay was used to detect plasma CNP. Metoprolol was used to treat children with POTS. The difference in plasma concentrations of CNP between responders and non-responders was compared. An ROC curve was used to analyze plasma CNP to predict efficacy of metoprolol on POTS in children. Plasma CNP in children with POTS was significantly higher than that of healthy children [(51.9 ± 31.4) vs. (25.1 ± 19.1) pg/ml, P <0.001]. Plasma CNP in responders to metoprolol was significantly higher than non-responders [(59.1 ± 33.5) vs. (34.8 ± 16.7) pg/ml, P = 0.037] before treatment. The ROC curve showed that area under the curve was 0.821 (95% CI 0.642–0.999). The cut-off value of plasma CNP > 32.55 pg/ml yielded a sensitivity of 95.8% and specificity of 70% in predicting therapeutic efficacy of metoprolol on POTS children. Plasma CNP might serve as a useful predictor for the therapeutic efficacy of metoprolol on POTS in children.

Evaluation of the changes in heart rate during head-up test predicting the efficacy of oral rehydration salts on postural tachycardia syndrome in children

To predict the therapeutic efficacy of oral rehydration salts (ORS) by quantifying changes in heart rate during the head-up test (HUT) in children with postural tachycardia syndrome (POTS). Fifty-four children from Peking University First Hospital during July 2005 to September 2013 were enrolled into POTS group. Twenty healthy children were enrolled in this study as the control group. Children with POTS were treated with ORS and successfully followed up. HUT test was done before and at the end of the treatment. POTS children were further divided into responding group and the non-responding group depending on if the symptom scores were reduced by 50% or greater after the treatment. The heart rate, systolic blood pressure (SBP) and diastolic blood pressure (DBP) changes during the HUT test were analyzed between the control group and the POTS patients. A receiver operating characteristic (ROC) curve was used to analyze the predictive value of the increase in heart rates (from the supine to upright) and the maximum upright heart rate in 10 minutes after ORS treatment. POTS children were 6-17 (11.3 ± 3.0) years old and the control group children were 10-12 (11.0 ± 0.8) years old. The changes of the heart rate during the HUT was different between the POTS patients and the controls ((41 ± 10) vs. (20 ± 7) beats/min, t = -10.441, P = 0.000) . There was no significant difference between the two groups in the maximum upright heart rate in 10 minutes during the HUT ( (117 ± 12) vs. (114 ± 8) beats/min, t = -1.322, P = 0.192) . The symptom scores were reduced compared with those before treatment ((3.2 ± 1.8) vs. (5.7 ± 2.0), t = 10.958, P < 0.001) and the heart rate changes from supine to upright were decreased in 30 patients ((33 ± 11) vs. (41 ± 11) beats/min, t = 2.956, P = 0.006). Compared with the non-responding group (28 cases), the heart rate change during the HUT test was great in the responding group (26 cases) before treatment ((46 ± 10) vs. (37 ± 9) beats/min, t = -3.582, P = 0.001), and the maximum upright heart rate in 10 minutes was also high in the responding group ( (122 ± 12) vs. (113 ± 10) beats/min, t = -2.693, P = 0.010). The ROC curve showed that ORS for children with POTS would be predicted to be effective when the pre-treatment increase of heart rate was 41 beats/min (sensitivity 72% and specificity 70%), or when the maximum upright heart rate in 10 minutes was 123 beats/min before treatment (sensitivity 48% specificity 56%). When the two indices were used together, sensitivity was 84% and specificity was 56%. The changes in heart rate during the HUT was useful in predicting the response to ORS in children with POTS.

The value of acetylcholine receptor antibody in children with postural tachycardia syndrome.

Postural tachycardia syndrome (POTS) is characterized by symptoms of orthostatic intolerance. Antibodies of acetylcholine receptor (AChR-ab) affect acetylcholine transmission between the ganglia and result in imbalance of the autonomic nervous system in POTS. This study was designed to analyze the clinical characteristics of POTS patients with AChR-ab positive and explore the value of AChR-ab in children with POTS. In 82 children with POTS, twenty patients (24.39%) were found as AChR-ab positive. Their clinical characteristics and hemodynamic responses to orthostatic changes were compared with the remaining 60 patients with negative AChR-ab. Symptoms of POTS children with AChR-ab positive were significantly severe than those of AChR-ab negative patients (p = 0.001). Preceding infection was predominant in patients with AChR-ab positive compared with that of patients with AChR-ab negative (p < 0.001). Syncope and fatigue were more common in the AChR-ab positive patients (p < 0.05). The change of upright heart rate was increased significantly in AChR-ab positive patients compared with AChR-ab negative cases (p = 0.013). Multiple logistic regression analysis revealed that preceding infection (OR 22.356, 95% CI 2.151-34.920), syncope (OR 11.570, 95% CI 2.098-63.810), and fatigue (OR 11.145, 95% CI 1.658-74.911) were independent risk factors for POTS with AChR-ab positive. In conclusion, POTS with positive AChR-ab was a heterogeneous disorder. Preceding infection, syncope and fatigue were their main clinical characteristics.

Changes of atrial natriuretic peptide and antidiuretic hormone in children with postural tachycardia syndrome and orthostatic hypertension: a case control study

Background The abnormal blood volume regulation is one of the most important pathogenesis in postural tachycardia syndrome in children. This study was designed to investigate the plasma atrial natriuretic peptide and antidiuretic hormone levels in postural tachycardia syndrome children, and their associations with the changes in heart rate and blood pressure in head-up test. Methods Twenty-one postural tachycardia syndrome patients ((12±2) years) and 26 healthy children ((12±1) years) were included. According to blood pressure changes in head-up test, the postural tachycardia syndrome patients were divided into two subgroups: postural tachycardia syndrome with orthostatic hypertension and postural tachycardia syndrome without orthostatic hypertension. The plasma atrial natriuretic peptide and antidiuretic hormone levels were measured using enzyme-linked immunosorbent assay. Results The plasma atrial natriuretic peptide level in postural tachycardia syndrome patients was higher than the control (P=0.004), whereas the difference in plasma antidiuretic hormone level between postural tachycardia syndrome and controls was not significant (P=0.222). The plasma antidiuretic hormone level of patients suffering from postural tachycardia syndrome with orthostatic hypertension was much higher than that of children having postural tachycardia syndrome without orthostatic hypertension (P &lt;0.05). In postural tachycardia syndrome patients, the upright max heart rate was positively correlated with the plasma atrial natriuretic peptide level (r=0.490, P&lt;0.05) and the upright systolic blood pressure was positively correlated with the plasma antidiuretic hormone levels (r=0.472, P &lt;0.05). Conclusions There was a disturbance of plasma atrial natriuretic peptide and antidiuretic hormone in postural tachycardia syndrome children. Chin Med J 2014;127 (10): 1853-1857