What Is A Heart Murmur?

Some think that a heart murmur in your dog is a condition.  It is, rather, a possible symptom of an underlying heart condition.  The murmur itself describes "turbulent blood flow through the heart", and that turbulence can be due to any one of a number of different congenital or acquired heart conditions. (congenital means they were born with it, and acquired means they developed the condition).

When you take your new dog to the vet for their first wellness exam, your doctor listens to their heart.  They listen for how many beats they are producing in a minute, but also they are listening for this turbulent blood flow…a murmur.  Heart murmurs are graded on a scale from 1-6, with 1 being the softest heard and 6 being the loudest.  A grade 1 heart murmur (and sometimes a grade 2) can be very difficult to hear for the inexperienced ear.  The grade is less about severity and more about how loud it sounds.

In an over-simplified nutshell, the heart has 4 chambers: the right and left atriums and the right and left ventricles.  There are valves that separate the atriums from the ventricles on both sides (tricuspid and bicuspid/mitral valve), as well as all the avenues through which the blood enters and leaves the heart.  As you can surmise, there are several places along the path for the blood flow to be turbulent.  The actual conditions our dogs may have are too numerous to list, and if your dog is diagnosed with a heart murmur, a cardiology expert will do an ultrasound of the heart and pinpoint your dog's problem.

Some breeds are predisposed to certain heart conditions, so it's key to do your research.  In the CGPR days, I recall only 2 dogs having a heart problem.  One had a condition called Supraventricular Tachycardia and the other had Subaortic Stenosis (a condition found mostly in larger dogs). On the whole, we haven't seen too many instances of heart disease in Pyrs, but a cardiologist is your best person to answer those questions.  Some conditions are merely seen more in larger dogs than small, and vice verse.  

All puppies are at risk of having a heart murmur upon birth, called an "innocent heart murmur".  This is why your doctor may heart a heart murmur in your pups at birth that goes away shortly into their new lives.  In a simple terms, their heart chamber fills with a blood volume that their vessels are just a bit too narrow for, and it creates a turbulence as the blood leaves the heart.   This goes away quickly into puppyhood; your veterinarian can educate you best on the timelines for this to become normal.  Our puppy had a heart murmur upon his 4 week visit, and it was gone by week 8 when we got him.

If your general veterinarian diagnoses your dog with a heart murmur, again this is only a sound they are picking up when they listen.  It's crucial you take your dog in to get an echocardiogram (ultrasound of the heart) to make a diagnosis. While these ultrasounds are not cheap, they will ensure your dog gets a proper diagnosis and will live as healthy as is their full potential.  I'm meeting more and more animals who are living longer, healthier lives with heart conditions, all due to the excellent care their owners provide coupled with the cutting edge treatments of cardiology specialists.  Definitely see a Board Certified Cardiologist, as their expertise is worth every penny!



by Shannon Murphy

Article on a special needs heart dog