Heart murmur

[Keystone]

Sorry, I am certain this has to have been covered before. I did a search and it said nothing?
So here's my new thread.
My Boxer is 11 years old. Besides from food allergies, she's been a very healthy dog.
Took her last week for her yearly check up and the vet announces she ( my dog) now has a heart murmur. Based on her description, it sounds like she was describing aortic stenosis. She said she can hear a level 3 murmur on both sides.
Last summer we did notice she couldnt make the walks anymore.
Vet sent us home with nothing, other then saying come back in in 2 weeks to give her time to research the best approach.
Does anyone have experiance with this? Does it matter that she's 11 and not a young pup? She has never had a murmur before, is a level 3 on both sides very bad news? What are we talking as far as how long she may have left? Like dig the hole now? Or she'll have the summer to enjoy, but not much else? Or can dogs go on for years? Is going from no murmur to a level 3 in one year considered fast? Or just normal progression?
Thanks for your help. Obviously I'm not looking for hard/fast facts exclusively, not expecting anyone to make promises of course... but I am clueless and would like some guidelines so I can be prepared for whatever the vet says.

[AussieGirl]

So sorry you have had that news. Has your vet done any further testing like an ECG, X Rays or an echocardiogram? They usually do at least an ECG to see if there is a problem with the heart that would be causing the murmur or if it has caused any damage. If not is it possible to see a vet specialising in Cardiology (I was just a little alarmed that they had to "research the best approach"). You said your girl has a level 3/6 did they explain the grading to you if not I found this;
Grades one and two: These are typically minor murmurs that don't require immediate medical intervention. Most vets will ask you to keep an eye on your dog as time goes on, and report right away if your dog develops a habitual cough or lethargy. These could be signs that the murmur is growing worse and may now require treatment.
Grades three and four: These murmurs are a bit more serious than grades one and two, so they are cause for more concern. At grade three or four, you may notice your dog tires quickly after exercise, and there may be a persistent cough that indicates some extra fluid is collecting in the lungs. Murmurs of these grades usually require medication to help regulate them.
Grades five and six: These are the most serious grades of murmurs. Dogs diagnosed at a five or six will require medication, and may also need surgery to try to repair the defect. Murmurs at this level may eventually develop into congenstive heart disease
Heart murmurs are common in Boxers and many live otherwise healthy lives - some may require medication or surgery but it all depends on the grade and the cause of the heart murmur and/or any damage the murmur has done.
You really need to know the underlying cause because there are a few things that can cause heart murmurs for example heartworm, anemia, heart valve disease and the treatment would vary depending on what is causing the murmur.
I know it's not much and you may already know this info but I hope it helps. Good luck and please keep us up to date with your girl.