Clinical significance of changes in T wave and ST segment amplitudes on electrocar-diogram from supine to standing position among children with unexplained chest tightness or pain in resting stage

Abstract:

Objective To investigate the clinical significance of changes in T wave and ST segment amplitudes on electrocardiogram (ECG) from supine to standing position in children with unexplained chest tightness or pain in resting stage. Methods A total of 122 6-14-year-old children with a chief complaint of unexplained chest tightness or pain (resting stage) underwent head-up tilt test (HUTT). According to HUTT results, these children were divided into HUTT-positive (n=61) and HUTT-negative groups (n=61). They underwent 12-lead ECG in the supine and standing positions, and heart rate and T wave and ST segment amplitudes in II, III, aVF and V₅ leads were measured. Results In the HUTT-negative group, heart rates were significantly higher in the standing position than in the supine position (P<0.05), T wave amplitudes in II, III, aVF, and V₅ leads were significantly lower in the standing position than in the supine position (P<0.05), and ST segment amplitudes in II, aVF and V₅ leads were significantly higher in the standing position than in the supine position (P<0.05). In the HUTT-positive group, heart rates were significantly higher in the standing position than in the supine position (P<0.05), T wave amplitudes in II, III, aVF and V₅ leads were significantly lower in the standing position than in the supine position (P<0.05), and ST segment amplitude in V₅ lead was significantly higher in the standing position than in the supine position (P<0.05). There were no significant differences between the two groups with respect to ST segment amplitude and T wave amplitude in II, III and aVF leads of the supine or standing position (P>0.05). Compared with the HUTT-negative group, the HUTT-positive group had significantly greater T wave amplitude differences in II, III, aVF and V₅ leads, and heart rate difference from supine to standing position (P<0.05). Conclusions Among the children with unexplained chest tightness or pain in resting stage, T wave amplitude differences in II, III, aVF and V₅ leads and heart rate difference from supine to standing position are greater in the HUTT-positive group than in the HUTT-negative group. This suggests that the changes in T wave amplitude on ECG from supine to standing position can indicate autonomic nervous system dysfunction.