Heart Tumor

A heart murmur is caused by a defect in the bloodflow through the heart... the heart tumor is cancer. Your best bet would be to select supplements that support the immune system and slow the growth of cancer. Fatty acids are great for slowing inflammation, and those would be good... as for the rest, I'm really not sure.

Whoa, not all tumors are cancerous.  I've had a number of fatty tumors removed...no sign of cancer.  If in fact this IS a cancerous tumor then you would want to eliminate grains from the puppers diet since cancer feeds on grains.
 
Other than that, I wish I could offer some suggestions.

Yeah, the first thing you have to determine is if it is malignant.  If so then you feed a cancer DIET (like Glenda said - no grain carbs -- and the easiest way to do that is home cook).  I would be glad to send you a sample from Dr. Clemmons -- it's got some other good info in it about anti-oxidants, etc.
 
Then you need to know WHERE the tumor is an exactly what it's doing -- is it making the heart not beat efficiently?  Is the blood flowing back into another chamber? 
 
What meds does the vet want to use? 
 
I had a dog with a hugely enlarged heart -- it was the result of massive heartworm disease.  But once we successfully treated it we used herbs and acupuncture (along with all the other things you mentioned) to help her heart do what it needed to do.
 
She was 10 1/2 when she came to us and we were told she'd live maybe a month.
 
Nope -- SIX AND A HALF YEARS (and her CGC and therapy dog certification later *smile*) she lived with us.  And she'd be proud to tell you she did NOT die of heart failure!!!
 
In Chinese medicine they teach that each body system has an opposite and what's hard on one thing affects the other.  So a dog with heart problems?  You MUST be kind to the kidneys and liver (they purify the blood that goes thru the heart -- get it??).  But most of the pharmaceuticals they give for heart stuff (lasix, etc.) are all HARD on the kidneys. 
 
You may truly want to ADD a vet.  Traditional Chinese Veterinary Medicine can help heart stuff SO much.  It can also help reduce the size of the tumor or at least keep it from growing..

I only know of one tumor commonly found on the heart, hemangiosarcoma. Its not usually a good one. Some dogs will live for years with no problems, others will die suddenly when the atria bursts. The only way to tell the difference between a heart tumor and heart cancer is to get a piece of the tumor... and thats just not easily done with heart tumors. Your best bet is to assume its cancer, and go from there.

Whoa, not all tumors are cancerous.  I've had a number of fatty tumors removed...no sign of cancer. 

I think the important distinction is that a regardless of whether or not a tumor is benign or malignant meaning invasive really doesn't matter with some locations. Anything on the heart, in the brain, head of pancreas, etc will cause problems purely because there is not area for spread. Compressive symptoms in these areas can be as bad as an invasive tumor. As Misskiwi said, hemangiosarcoma (which is malignant) is most common in dogs (in people it's an atrial myxoma which is benign) and it sounds like it has caused a pericardial effusion or pleural effusion since you said there was fluid taken off. Benign tumors typically don't cause effusions, just push on thing they shouldn't. I think its always good to optimize nutrition and add some anti inflammatory like the omega 3's as suggested before. I'm so sorry you are going through this Soonler I wish I could give you some more useful advice

I'll keep you all in my prayers!

I am so sorry to hear this.  My dog collapsed suddenly and was found to have a tumor on the heart and arrythmia.  The cardiologist put her on procainamide 3x day.  She lasted another 3 months. He told me she would suddenly die when her heart stopped and thats what happened. 
    She was on a raw diet, fish oil, salmon oil, C prior to the attack. I've come to terms that it was part genetics, part Lyme disease, part over vaccinations.  I am still devastated.  I hope it turns out better for you.   

I'm sorry I didn't persue this, but I heard Chinese herbs can shrink tumors.  I alos heard parsley is good to fight tumors.