The Heart and the Circulatory System Introduction Imagine that you are living in the year 1535, and that you don't feel well. You have had some problems with fatigue, feeling a little more tired than usual when you walked to the market and back. You tell this to your physician, and he sends y...

Congenital heart disease (or CHD) is a range of heart disorders, of varying degrees of severity, which are present at birth. CHD affects about eight in every one thousand live babies that are born and is caused by factors operating early in pregnancy. These factors include viral infections (e.g. Rub...