Plasma hydrogen sulfide in differential diagnosis between vasovagal syncope and postural orthostatic tachycardia syndrome in children

摘要

Objective: To explore the predictive value of plasma hydrogen sulfide (H 2S) in differentiating between vasovagal syncope (VVS) and postural orthostatic tachycardia syndrome (POTS) in children. Study design: Patients were divided between the POTS group (n = 60) and VVS group (n = 17) by using either the head-up test or head-up tilt test. Twenty-eight healthy children were selected for the control group. Plasma concentrations of H 2S were determined for children in all groups (POTS, VVS, and control). Results: Plasma levels of H 2S were significantly higher in children with VVS (95.3 ± 3.8 μmol/L) and POTS (100.9 ± 2.1 μmol/L) than in children in the control group (82.6 ± 6.5 μmol/L). Compared with the VVS group, the POTS group had plasma levels of H 2S that were significantly increased. The receiver operating characteristic curve for the predictive value of H 2S differentiation of VVS from POTS showed a H 2S plasma level of 98 μmol/L as the cutoff value for high probability of distinction. Such a level produced both high sensitivity (90%) and specificity (80%) rates of correctly discriminating between patients with VVS and patients with POTS. Conclusion: H 2S plasma level has both high sensitivity and specificity rates to predict the probability of correctly differentiating between patients with VVS and patients with POTS.