Getting "The Bar" (Implanon)

I'm 17 and have recently been diagnosed with a very serious heart and lung condition which means i can't ever have children as it would kill both the baby and myself. I was on the combined pill to regulate my periods and because i'm active but that is also very dangerous for me to be taking so the doctor recommened getting Implanon. I know nothing about it, the side effects or the advantages? Anyone know anything about it?