RESUMO
OBJECTIVE: To explore whether hemocytometric measures could be qualified predictors for the effect of oral rehydration salts (ORS) in children with postural tachycardia syndrome (POTS). STUDY DESIGN: Thirty-five children with POTS and 29 healthy children were enrolled. General information, hemodynamic status, and baseline hemocytometric variables were collected. Children with POTS received ORS therapy and were followed up for 3 months. The independent risk factors of developing POTS were explored. A receiver-operating characteristic curve was used to evaluate predictive value of hemocytometric variables for therapeutic effectiveness of ORS therapy. RESULTS: Children with POTS had larger mean corpuscular volume (MCV) and lower mean corpuscular hemoglobin concentration (MCHC) values than controls (P < .05). The baseline MCV values positively correlated with heart rate elevation from supine to upright (r = 0.294, P < .05). Both larger MCV and lower MCHC values were independent risk factors of developing POTS (for MCV, P < .05, OR 1.222; for MCHC, P < .05, OR 0.936). In children with POTS, responders to ORS had baseline lower MCV and higher MCHC than nonresponders (P < .05). The receiver-operating characteristic curve for the predictive value of MCHC showed that area under the curve was 0.73. CONCLUSIONS: MCHC values could be used to predict the effectiveness of ORS for treating POTS in children.
Assuntos
Hidratação/métodos , Síndrome da Taquicardia Postural Ortostática/fisiopatologia , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Hemodinâmica/fisiologia , Humanos , Masculino , Síndrome da Taquicardia Postural Ortostática/terapia , Curva ROC , Resultado do TratamentoRESUMO
OBJECTIVE: To explore whether electrocardiography (ECG) variables could be used to predict responses to physical treatment in children with postural tachycardia syndrome (POTS). STUDY DESIGN: Forty children with POTS and 32 healthy controls were enrolled in this study. General information and hemodynamic and supine ECG variables, including QT interval dispersion (QTd), were collected. The children with POTS received physical treatment and 3 months of follow-up. A receiver-operating characteristic curve was used to evaluate the value of ECG variables for predicting the effectiveness of physical treatment. RESULTS: Compared with the healthy children, the children with POTS had longer baseline QTd and heart rate (HR)-corrected QTd (QTcd), but shorter minimum QT intervals (QTmin) and minimum HR-corrected QT intervals (P < .05). In children with POTS, responders to physical treatment had a longer baseline time between QRS complexes (RR) interval of minimum QT interval and a longer QTcd compared with nonresponders. A longer QTcd was a significant risk factor for the presence of POTS (OR, 1.022; P = .02) and for undesirable responses to physical treatment in children with POTS (OR, 1.044; P = .03). Baseline QTcd was positively correlated with the HR elevation from supine to upright seen in children with POTS (r = 0.348; P = .003). Receiver operating characteristic curve analysis demonstrated an area under the curve of 0.73, and using 43.0 msec as a cutoff of QTcd yielded a sensitivity of 90% and a specificity of 60%. CONCLUSION: QTcd might be useful for predicting the effectiveness of physical treatment for POTS in children.