Time-dependent heart rate variability in the head-up tilt test in children with postural orthostatic tachycardia syndrome / 中国当代儿科杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study the time-dependent heart rate (HR) variability in the head-up tilt test (HUTT) in children with postural orthostatic tachycardia syndrome (POTS) and to explore the HR diagnostic criteria for POTS in children.</p><p><b>METHODS</b>A retrospective analysis was performed on the clinical data of 105 children diagnosed with POTS with HR≥120 beats per minute (bpm) within the first 10 minutes of HUTT between January 2007 and December 2014. Their HR variability within the first 10 minutes of HUTT was analyzed.</p><p><b>RESULTS</b>The HR of children with POTS increased gradually from the supine position to a 60° head-up tilt position, and the increase in HR was 24±12 bpm at the beginning of HUTT, 30±14 bpm at 3 minutes of HUTT, 32±13 bpm at 5 minutes of HUTT, and 38±12 bpm at 10 minutes of HUTT. The average maximal HR increase within the first 10 minutes of HUTT was 43±10 bpm.</p><p><b>CONCLUSIONS</b>In children with POTS, the HR variability gradually increases with time, and therefore, it is suggested that HR increase ≥40 bpm is more suitable for diagnosis of POTS in children.</p>