Runt puppy has heart murmur

Question
Hi,
I have a toy poodle puppy who is 5 months old. I've took her to the vet and discover that she had heart murmur...what should I do? Will she have shorter life span? And what exactly is heart murmur and what can I do to fix it? Is surgery help? I love her so much and I really dont want to lose her.... The vet suggest me to bring her back in 1 month and check......Will heart murmur heal by herself? I mean she is runt of the litter and only 1.4kg....Please help

Answer
There are many causes for heart murmurs. Some are congenital, that is they were born with them, and some develop later in life. Some congenital ones are outgrown, but there is no way of knowing until that happens. Depending on the 'grade' of the murmur, the dog can live a normal life in most cases. They are graded by severity.

As the Merck Veterinary manual states:

It is imperative to appreciate that the presence of a heart murmur in a young animal is not pathognomonic for a congenital heart defect. Many young animals will have a low-grade systolic murmur that is the result of mild turbulence and is not associated with a congenital heart defect. These murmurs usually disappear by 6 mo of age in dogs and cats. Innocent murmurs are heard in the absence of any other demonstrable evidence of cardiovascular disease.

So I wouldn't worry too much at this point. Your vet must think that the murmur lies along these lines and that's why he wants to recheck her later. So just make sure she gets a good diet (like Science Diet Puppy Growth Small Bites) and not garbage store food or Nutro or Iams.
That will give her a complete and balanced foundation to help her grow strong.
Don't feed her treats- they are full of salt and sugars. No table food either. Feed her strictly on the Science Diet puppy growth and she will do really well.

I am sure the murmur is mild at this point. If you are worried, call your vet again and ask him to repeat what he told you in the exam room. I am sure that you were upset and forgot most of what he said after you heard "Heart Murmur."
It's common!!
Let me know how she is after her next check up.