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PEDIATRIC ELECTROCARDIOGRAM NORMS
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Normal ECG at Age Intervals (Newborn, 1MO, 3MO, 12MO, 3Y, 5Y, 8Y, 13Y)
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Many different presentations to the pediatric emergency department (ED) warrant electrocardiogram (ECG) evaluation. These include common complaints such as chest pain, syncope, palpitations, drug exposure, and electrical burns. In young infants and neonates, an ECG may be indicated for poor feeding, cyanotic spells, or an acute life-threatening event. There are age-related changes that dramatically alter the appearance of the “normal” ECG in children (Table 8.1), and the first step in interpretation of the pediatric ECG should be noting the patient’s age. The normal range for heart rate for a newborn to an infant 6 months of age is 125 to 145 beats per minute (bpm). The mean adult resting heart rate of 80 bpm is not reached until adolescence. In neonates, due to fetal circulation, the right ventricle is dominant. This leads to a normal right axis deviation in ECGs of infants. Smaller muscle mass also leads to a shorter PR interval as well as QRS duration. In younger children, the PR interval ranges between 0.08 and 0.15 seconds and in adolescents between 0.120 and 0.2 seconds. QRS duration in patients aged less than 8 years should not exceed 0.08 seconds. Adolescent QRS intervals range from 0.1 to 0.12 seconds, the latter being the normal duration for adults. The QT interval in infancy is also slightly longer. Since the QT interval varies with heart rate, calculation of the corrected QT interval is indicated. The upper limit of normal for the QT interval in infancy is 490 milliseconds, and decreases to 440 milliseconds after 6 months of age. In addition, R-wave progression does not follow the normal adult pattern until the patient is approximately 6 to 8 years of age.
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T-wave changes in pediatric ECGs are nonspecific, and absolute rules for age-related changes ...