The hidden challenges of detecting canine heart murmurs

During an interview with dvm360, Stephen Maschmedt, BVSc (hons), MBA, shared some insight as to why detecting canine heart murmurs with a traditional analog stethoscope is often harder than it sounds—from soft, easily missed murmurs and imperfect stethoscope placement to noisy clinics, anxious dogs, and the muffling effects of obesity that all conspire to hide early heart disease.

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Below is a transcript of the episode, edited lightly for clarity.

dvm360: Starting with your name, can you tell me a little bit about yourself?

Stephen Maschmedt, BVSc (hons), MBA: Sure, so my name is Steve Maschmedt. I head up the pet veterinary professional services team at Boehringer Ingelheim in the US. As you can tell by my accent, I'm not from the US. I graduated from vet school in Melbourne, Australia. Spent about 5 years in general practice, and then I've been with Boehringer Ingelheim in a range of different roles in Australia, Germany and the US over the past 18 years.

dvm360: How has detecting heart murmurs in dogs traditionally been challenging in general practice setting?

Maschmedt: Typically, vets use an analog stethoscope for listening to heart and lung sounds during routine medical checkups. But what we find is that sometimes detecting a heart murmur with the stethoscope alone can be challenging for a range of different reasons.

So the first one is that some more murmurs may be inaudible, so soft or moderate murmurs may be missed or overheard. The second one is the murmur location, so some murmurs may be missed if the stethoscope is not placed over the murmurs highest point of intensity. The third one, I think a big one, is the busy clinic. So, you know, the activities, the sounds in a busy clinic, as well as panting stress dogs sometimes make the murmurs a bit challenging to detect. The fourth one is dog anxiety. So stressed dogs, they have an increased heart rate, they can make murmurs a bit more challenging to detect.

And then a lot of dogs are sort of overweight or even obese. And obesity can result in sometimes muffled heart sounds, which may reduce the sensitivity of detecting some heart murmurs.