Transition from pediatric to adult electrocardiogram

Transition from pediatric to adult electrocardiogram

As the infant grows up, the heart rate gradually decreases. While the mean heart rate for a neonate is around 130 per minute, that of an adolescent would be around 80 per minute. The QRS axis gradually shifts from the right axis deviation at birth to the normal adult axis. This is because the right ventricle which is dominant before birth regresses and left ventricle takes over as the dominant ventricle. PR interval gradually increases with age. QRS duration also gradually increases with age. The Rs pattern in V1 indicating a dominant right ventricle shifts to rS pattern as the right ventricle regresses and left ventricle becomes dominant.

The R wave height in V6 increases as the neonate grows up, for the same reason. The corrected QT interval may shorten a little bit as the infant grows up. The T wave which is upright at birth becomes inverted in a few days. Persistence of an upright T wave in V1 in children indicates right ventricular hypertrophy. Respirophasic sinus arrhythmia is a usual finding in normal healthy children and is one of the commonest causes for referral due to an irregular heart rhythm. A shifting atrial pacemaker with varying P wave morphology is also a common observation in the pediatric age group.