Does my dog have Heart Disease or Heart Failure?

My 8 yr old black lab, Nala has been swollen for over a month in and out of the vet. They give her diuretic and it goes down then comes right back finally went to see a specialist. She did an x-ray and drained fluid in her chest cavity but told me her heart looked good. All labs are good but she sent the fluid from her chest out and now tells me it's indicating something is wrong with her heart. And we are going for an ultrasound on Friday. I'm so scared - How long can a dog live on Meds for heart failure?
40 minutes ago - 1 week left to answer.
Additional Details
3 minutes ago

When the specialist did the x-ray she also did just a quick ultrasound for me to look at her heart and look around for any tumors. She didn't find any tumors and she said she didn't measure her heart but that it looked good that she didn't see any signs of heart failure but said but I didn't measure anything.

Well, there is certainly something wrong. It's hard to diagnois from here, naturally.

However I can tell you dogs can live long on heart medication, depending on what the underlying issue is.

You are doing the right things. Get to a canine cardiologist, as it seems you are doing, get the echo which will tell you a lot, and if they are having difficulty figuring out what to do, ask for a referral to a vet school near you (if there is one). Vet schools are much less expensive than regular vets, although you have to wait around a lot more and the students are caring for your dog -- which I've found is a real good thing, as they are fresh and totally motivated to do the best they can. I love vet students!!

Just wait for the vet's answer,
My dog lived for about another year and a half on heart meds, but we finally put him to sleep,
I'm so so sorry, I know it can be hard "/
I hope Nala gets better!

ONLY YOUR VET will be able to answer this for you once all the test are done

Sorry about your dog, hope gets well soon

just listen to the vet, and she will be fine..

yes, have heard of dogs with heart problems living a long time on heart meds, just listen to your vet okay.

take it easy, if you are stressed, your dog will be also, she can sense it from you..stay calm and she will also..

good luck

Breeder/show/handler 15 yrs

if vet found no tumors or heart problems and she is just retaining fluids and some dogs do, you may have to keep on meds to control it..bless her heart