> I hear of so many puppies going for a check up when they go to new owners that appear to have heart murmurs.....but once the puppy has settled into its new home the murmur disappears. Could it be stress related?.
It is commonly due to the switch over, at the moment of birth, from a single circulatory system (ie no lung involvment) to a double one.
The opening that takes blood from the heart (through the Pulmonary artery) to the lungs, is closed until the moment of birth and the opening which once took blood to the placenta needs to close.
Quite a lot to do in that first breath so can take a little longer...up to 12-14 weeks in fact for it all be sorted. This delayed developmental murmur is what is generrally called 'flow murmur'.
There are, however, other places in the heart that can send out abnormal heart sounds, immature valves for example.
It is possible that an abnormal heart sound comes from a congenital ( made up wrong in development of feotus) problem which wont resolve.
The stress theory wouldn't have applied in the case of my whole litter suffering from FM as I had kept all 3 and didn't let them go until they were declared perfect.
I didn't want the 'stress' of other vets telling my puppy owners that they had a tragic situation on their hand..... which it patently wasn't.
The reason it is first picked up by new owners vet is because that is usually the first time anyone has listened to their heart