Midodrine hydrochloride is effective in the treatment of children with postural orthostatic tachycardia syndrome.

BACKGROUND The study was carried out to examine the effect of selective α1 adrenoceptor agonist midodrine hydrochloride vs. β-adrenergic blockade metoprolol in the treatment of children with postural orthostatic tachycardia syndrome (POTS). METHODS AND RESULTS Fifty-three children with POTS were divided into group I (midodrine hydrochloride plus conventional therapy), group II (metoprolol plus conventional therapy) and group III (conventional therapy). Standing test was conducted for all participants. The cure rate, improvement rate, effective rate and score of symptoms were compared among the 3 groups. A Kaplan-Meier survivorship curve was used to describe the proportion of symptom-free cases during a long term follow-up. The cure rate and effective rate at the end of short term follow-up in group I were significantly higher than those of group II and group III (68.42% vs. 42.11% vs. 20.00%, P<0.05; 89.47% vs. 57.89% vs. 53.33%, P<0.05). After treatment, the symptom score in group I was significantly lower than group II and group III, respectively (1.1±2.2 vs. 2.8±2.4 vs. 3.7±2.0, P<0.05), and it also had significant difference between group II and group III (P<0.05). The symptom recurrent rate in group I was significantly lower than that of group II and group III, respectively (P<0.05), but it did not differ between group II and group III (P>0.05). CONCLUSIONS Midodrine hydrochloride is effective in the treatment of children with POTS.