Baseline left ventricular ejection fraction associated with symptom improvements in both children and adolescents with postural tachycardia syndrome under metoprolol therapy.

BACKGROUND: Postural tachycardia syndrome (POTS) is a common childhood disease that seriously affects the patient's physical and mental health. This study aimed to investigate whether pre-treatment baseline left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) values were associated with symptom improvement after metoprolol therapy for children and adolescents with POTS. METHODS: This retrospective study evaluated 51 children and adolescents with POTS who received metoprolol therapy at the Peking University First Hospital between November 2010 and July 2019. All patients had completed a standing test or basic head-up tilt test and cardiac echocardiography before treatment. Treatment response was evaluated 3 months after starting metoprolol therapy. The pre-treatment baseline LVEF and LVFS values were evaluated for correlations with decreases in the symptom score after treatment (ΔSS). Multivariable analysis was performed using factors with a P value of <0.100 in the univariate analyses and the demographic characteristics. RESULTS: A comparison of responders and non-responders revealed no significant differences in demographic, hemodynamic characteristics, and urine specific gravity (all P > 0.050). However, responders had significantly higher baseline LVEF (71.09% ±â€Š4.44% vs. 67.17% ±â€Š4.88%, t = -2.789, P = 0.008) and LVFS values (40.00 [38.00, 42.00]% vs. 36.79% ±â€Š4.11%, Z = -2.542, P = 0.010) than the non-responders. The baseline LVEF and LVFS were positively correlated with ΔSS (r = 0.378, P = 0.006; r = 0.363, P = 0.009), respectively. Logistic regression analysis revealed that LVEF was independently associated with the response to metoprolol therapy in children and adolescents with POTS (odds ratio: 1.201, 95% confidence interval: 1.039-1.387, P = 0.013). CONCLUSIONS: Pre-treatment baseline LVEF was associated with symptom improvement after metoprolol treatment for children and adolescents with POTS.

Increased Endogenous Sulfur Dioxide Involved in the Pathogenesis of Postural Tachycardia Syndrome in Children: A Case-Control Study.

BACKGROUND: The pathogenesis of postural tachycardia syndrome (POTS) remains unclear. This study aimed to explore the changes and significance of sulfur dioxide (SO2) in patients with POTS. METHODS: The study included 31 children with POTS and 27 healthy children from Peking University First Hospital between December 2013 and October 2015. A detailed medical history, physical examination results, and demographic characteristics were collected. Hemodynamics was recorded and the plasma SO2was determined. RESULTS: The plasma SO2was significantly higher in POTS children compared to healthy children (64.0 ± 20.8 µmol/L vs. 27.2 ± 9.6 µmol/L, respectively, P < 0.05). The symptom scores in POTS were positively correlated with plasma SO2levels (r = 0.398, P < 0.05). In all the study participants, the maximum heart rate (HR) was positively correlated with plasma levels of SO2(r = 0.679, P < 0.01). The change in systolic blood pressure from the supine to upright (ΔSBP) in POTS group was smaller than that in the control group (P < 0.05). The ΔSBP was negatively correlated with baseline plasma SO2levels in all participants (r = -0.28, P < 0.05). In the control group, ΔSBP was positively correlated with the plasma levels of SO2(r = 0.487, P < 0.01). The change in HR from the supine to upright in POTS was obvious compared to that of the control group. The area under curve was 0.967 (95% confidence interval: 0.928-1.000), and the cutoff value of plasma SO2 level >38.17 µmol/L yielded a sensitivity of 90.3% and a specificity of 92.6% for predicting the diagnosis of POTS. CONCLUSIONS: Increased endogenous SO2levels might be involved in the pathogenesis of POTS.

[A family-based transmission disequilibrium test of polymorphisms of endothelial nitric oxide synthase gene in children with orthostatic intolerance].

OBJECTIVE: Recent studies have found that the variation of G894T on the region of T786C and 7th exon promoted by endothelial nitric oxide synthase (eNOS) gene is associated with cardiovascular disease. This research explored possible correlations between eNOS gene polymorphisms and orthostatic intolerance (OI) in children through linkage disequilibrium analysis between eNOS genes T786C and G894T and OI. METHODS: PCR, Macrorestriction Map and other molecular biotechnology were used to determine the genotypes of eNOS/T786C and G894T in 60 OI probands and their parents. Correlation analysis and transmission disequilibrium test (TDT) between T786C, G894T and OI were performed. RESULTS: There was linkage disequilibrium of eNOS/T786C and G894T gene polymorphisms in the occurrence of childhood OI (P<0.05). CONCLUSIONS: eNOS genes T786C and G894T may be associated with the pathogenesis of OI.