Normal limits of the high-fidelity pediatric ECG. Preliminary observations.

A study of more than 1,780 neonates, infants, and children was carried out, using a digital electrocardiograph with a sampling rate of 500 per second, to revise the normal limits of the pediatric ECG. The 12-lead ECG was used with V4R replacing V3. All leads were recorded simultaneously off-line in digital form on magnetic tape and were subsequently analyzed using well-established computing techniques. The results showed that the upper 98 percentile limit of normal amplitudes could be up to 46% higher than previously published limits. Differences in some mean values were very much higher, though these are of less clinical significance. In addition, QRS durations were found to be wider than previously published data. Sex-related differences could be demonstrated in both amplitude and duration measurements, particularly in the early adolescent years. This study confirms that to record pediatric ECGs with high fidelity, it is necessary to use equipment that converts the ECG from analog to digital form at a rate of 500 samples/sec. Significant errors in amplitude and duration measurements may be expected if a much lower sampling rate is utilized.