Let me say first, that my experience with enlarged hearts is with humans, not dogs - so some of what I say might be incorrect in relation to dogs - but I DO know that dogs sometimes develop enlarged hearts.
An enlarged heart usually means congestive heart failure (CHF). The heart become enlarged because it is working too hard to pump out the blood throughout the body. It is exactly the same as when you lift weights to build up your muscles and make the larger - the heart is a muscle and when it is overworked, it gets larger. Unfortunately, that is not a good thing for the heart.
It can happen if the heart was attacked by a virus, or if there are birth defects in the heart, or if the dog has experienced a heart attack.
I'm confused by the low heart rate though, because the heart rate is often faster in CHF in an effort to get more blood to the body.
If your baby is older, this may be a part of aging - that does not mean that all older dogs have it, but sometimes it develops as dogs (and humans) age.
If your baby is younger, this is not a good sign, although CHF can be controlled in some cases with heart medication.
You definitely need the ultra sound and need a vet who is well versed in canine heart problems.
Good luck, let us know what happens.
__________________  Rex & Rowdy's Mom  |