I'm not anti u/s but I do know that not all heart defects are picked up by fetal ultrasound. My SIL had many u/s during her last pregnancy b/c she is type 1 diabetic and over 40 and very high risk. They even did a fetal echo since there is a greater possibility of heart defects and nothing showed up. However her son was born and after hearing a heart murmur, they followed it up with another echo and found out that he had tetralogy of fallot. He had heart surgery at 2 months old because of it.
I am definitely sure that the anatomy scan does save lives, especially for babies that need immediate assistance after birth but it may not pick up everything. A good newborn check will hopefully pick up anything that was missed.