Normal neonatal ECG

Electrocardiogram from a healthy neonate resembles right ventricular hypertrophy in adults (tall right precordial R waves with right axis deviation). Right ventricular preponderance in neonates is a physiologic finding related to fetal circulatory dynamics; resting sinus tachycardia is expected. The very narrow QRS (only about 0.05 sec) is a major clue in differentiating this pattern from a pathologic one in adults.