Guest post from my daughter Sneha Krishnan. She is a 3rd year DVM student at Colorado State University in Fort Collins Colorado
We think of the heart as the most important organ. Responsible for life, for us to stand up, move, walk, run – to keep us alive. It is quite interesting to look at the differences between hearts of the many species that came before us. Looking back at primitive fish with a very simple 2 chambered heart, it is fascinating to think now that humans have a very complex 4-chambered heart with various pressures, velocities and flows at different parts. The alignment of each component of our complex hearts is essential to keep us healthy. This is true for humans and all animal species we deal with.
Veterinarians deal with cardiac disease quite often.
There are many similarities and many differences between the pathologies of human and animal hearts. One thing to note is that there is so much variety within animal species themselves. For example, a toy breed dog’s heart and a Great Dane’s heart look vastly different on an x-ray, and have very different disease types. As veterinary students, we learn extensively about breed-specific disease, as almost 90% of some breeds can have a heart disease by middle to old age.
On our virtual cardiology rotation this week, we learned about the general aspects of cardiology starting with the anatomy, then moving to diagnostic modalities. The typical workup of a patient with suspect cardiac disease often happens when a student or veterinarian is doing a routine exam and hears a murmur with their stethoscope. A murmur is an abnormal heart sound that can be caused by various valvular or structural diseases. When hearing a murmur, an experienced veterinarian usually assigns a grade to the murmur, which then determines the urgency of the case for a full work up. Let’s say your dog was diagnosed with a grad 5/6 murmur on the left side. This would be an indication to dig deeper to find and treat the cause of this murmur.
Other things to consider are the age of the dog and the breed of the dog. A puppy can also present with a murmur, but usually for a totally different reason than a 10 year old dog. Many animals are born with anatomic abnormalities in their heart that happened during development. A common one is a patent ductus arteriosus, which is a failure of a duct to close after birth, causing oxygenated blood to get pushed into the pulmonary arterties, overloading the lungs with blood.
So once you hear the murmur, the next thing to do is an x-ray to evaluate the heart and lungs. If that shows something abnormal, you continue with an echo cardiogram, which is an ultrasound of the heart that will give you a better idea of what is happening within each chamber, valve, etc. See above echo image
Other cool things we get to look at – exotic species! Ferrets, rabbits, donkeys, moose, bears, you name it! These species all get heart disease and we can diagnose them just like we do in dogs and cats. Here’s a picture of a snake with congestive heart failure. Fun fact, a snake’s heart rate can be as low as 30-40 normally.
Animal world is definitely exciting due to it’s diversity.