
I personally think you should simply re read this whole thread as the answer in my opinion is there before you. :-)
It is very rare for a bitch to lose a litter at 8 weeks in whelp. The heart nurmour alone would put the bitch at risk especially considering she has had a bad collapse already and lost the last litter. This is not a common occurance for a healthy bitch.
From what I have read most heart murmours that are not picked up in puppyhood are caused by degenerative valvular disorders, if it was a trauma it would I imagine it to have been a considerable large trauma, like a human in a car crash. Would the breeder remember if she had sustined such a trauma. Either way inherant or through trauma for me she isn't fit enough.
She has the grand daughter so has the lines. Keep two bitch from her litter or a future one, she has just had one recently so what is in that? If she is the grand daughter she must be fairly young compared to the grand-mother so a future litter should be possible.
It is easy to get caught up in line sentiment but trauma like that is not paticular good or nice for the bitch. ( I mean the lose pups etc)
It only comes back and bites you in the bum I think later on.