Keith⁰ in 1956 showed that the deaths from congenital heart disease occur chiefly in the first year of life.

Cardiac surgery has advanced rapidly and provided a constant stimulus to the development of precise diagnostic methods. Cardiac catheterization may have to be abandoned at any stage, so speed is essential, and any method of reducing the length of time required for the investigation is of value. An electrocardiogram recorded inside the heart by an electrode at the tip of the catheter is most helpful.

This paper illustrates a few of the ways in which the routine use of intracardiac electrocardiography can make cardiac catheterization in newborns, infants and children quicker, safer and more informative.