Efficiency of heart rate and heart rate difference at different time points during head-up tilt test in the diagnosis of postural tachycardia syndrome in children and adolescents

Abstract

To study the efficiency of heart rate (HR) and heart rate difference (HRD) at different time points during head-up tilt test (HUTT) in the diagnosis of postural tachycardia syndrome (POTS) in children and adolescents. A total of 217 children and adolescents, aged 6-16 years, who were diagnosed with POTS were enrolled as the POTS group, and 73 healthy children and adolescents, matched for sex and age, were enrolled as the control group. The POTS group was further divided into ≤12 years old group with 127 children/adolescents and >12 years old group with 90 children/adolescents. The two groups were compared in terms of HR at baseline and at 5 and 10 minutes of HUTT (HR0, HR5, and HR10 respectively), difference between HR5/HR10 and HR0 (HRD5 and HRD10 respectively). The efficiency of HR5, HR10, HRD5 and HRD10 in the diagnosis of POTS was assessed. Compared with the control group, the POTS group had significant increases in HR5, HR10, HRD5, and HRD10 (P<0.05). The coincidence rate of HR or HRD for the diagnosis of POTS in males was higher than that in females at 5 minutes of HUTT (P<0.05), while the coincidence rate of HR or HRD for the diagnosis of POTS in males was lower than that in females at 10 minutes of HUTT (P<0.05). The coincidence rate of HR for the diagnosis of POTS was higher in the >12 years old subgroup (P<0.05), while the coincidence rate of HRD for the diagnosis of POTS was higher in the ≤12 years old subgroup (P<0.05). The combination of HR5, HR10, HRD5, and HRD10 for the diagnosis of POTS had a greater area under the curve (0.974; 95%CI: 0.949-0.989) than HR5, HR10, HRD5, or HRD10 alone, with a sensitivity of 87.80% and a specificity of 95.83%. The diagnostic efficacy of HRD for POTS was higher than that of HR (P<0.05). HR and HRD at different time points during HUTT have a good value in the diagnosis of POTS in children and adolescents, and the accuracy of diagnosis varies with age and gender.