They're ignorant, don't pay them any mind! If it were a procedure your child needed right now, yes, I imagine you too would go outside slow insurance but you want to just see the cardiologist you saw before, get an examination to start getting any future help your child may need.

Their advice doesn't make sense, even to them if they think about it! It's fine to "go outside insurance to get help" but go where? You want to pick a doctor out of a hat to see or wait until your pediatrician/health insurance recommends someone appropriate? He's not needing open heart surgery tomorrow; just a good checkup appointment from a specialist!