[Variance of signal-averaged electrocardiographic parameters with age in normal children].
The high-frequency components of the surface QRS was analyzed quantitatively in 87 normal infants and children. The subjects were categorized in 4 groups by age; Group A: one day (n = 27), Group B: 1-5 years (n = 20), Group C: 6-10 years (n = 20), Group D: 11-15 years (n = 20), and the results were compared among the 4 groups. Signal-averaging and high-pass, bidirectional and digital filtering were used for analysis. The total duration of the QRS, the duration of the low-amplitude signals (< 40 microV) in the terminal portion of the QRS (U 40), the amplitude of the signals in the QRS (RMS; QRS) and the amplitude of the last 40 msec of the QRS (RMS 40) were measured at high-pass filter frequency settings of 25, 40, 60 and 100 Hz. Statistical analysis was performed with the unpaired t-test. Differences were considered significant if p < 0.05. The results were as follows: 1. At all filters, the durations of the QRS and U 40 were longer in the order of Groups A < B < C < D, and the amplitude of the RMS; QRS and RM 40 were greater in the order of Groups D < C < B < A. 2. There were significant differences in the QRS between the groups at all filters. 3. There were significant differences in U 40 between the groups except between Groups B and C at 25-Hz filter, but at 40-, 60-, 100-Hz filters, there were no significant differences among Groups B, C and D.(ABSTRACT TRUNCATED AT 250 WORDS)
Tsuchida
A
A
Department of Pediatrics, Asahikawa Medical College.
Oka
R
R
D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography / Q000379:methods* / Q000592:standards*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012815:Signal Processing, Computer-Assisted