The Role of Axis Deviation in Congenital Heart Diseases

There are certain congenital heart diseases that give you characteristic axis abnormalities. About 50% of kids with trisomy 21 have a congenital heart problem. Have an AV canal defect? Your ventricles end up depolarizing from bottom up as opposed to top down. And that gives you a characteristic superior axis where you see a QRS that's negative in lead AVF.