Knowledge of the basics of pediatric ECG interpretation is helpful in differentiating normal from abnormal findings. These basics include familiarity with the age-related normal findings in heart rate, intervals, axis, and waveform morphologies; an understand-ing of cardiac physiologic changes associated with age and maturation, particularly the adaptation from right to left ventricular predominance; and a rudimentary understanding of common pediatric dysrhythmias and findings associated with congenital heart diseases.