Hi Cathy, glad to meet you
I am currently on my third round of Navelbine/Herceptin combo, since 2001 with Herceptin as manintenance therapy in between, for mets to my lymph system; each round lasts for 6 months and we've been able to keep the mets confined to the lymph system with few major side effects. Navelbine is an extremely effective chemo, and has a synergistic effect with Herceptin, so you will hopefully be able to beat those mets back and keep them there with the help of Herceptin.
Quite a few on this site have had good results with this combo, so I'm sure you'll hear from them as well.
Has your ejection fraction been checked again, before you start Herceptin, so you have a "baseline" reading to go from? It could be that your previous low score was due to receiving Herceptin so soon after you had AC, but enough time has gone by that you should now be fine. However, your onc will want to monitor your heart from now on, I have either an ECHO or MUGA every six months for that reason.
Again, welcome and good luck with your first dose Friday!
<3 Lolly