Author: Dr. Brenda Gough
….only the two most important organs in the body….!
When your pet comes in for an exam, one of our animal care attendants has a listen to the heart. They are taking measurements for us – they do a temperature, heart rate and respiratory rate for us so that we have a solid database before we doctors even get into the room. They can’t comment on arrhythmias, heart murmurs, respiratory wheezes and crackles, etc. although our staff are very well trained and usually pick up on these things.
When the doctors listen to the heart, we are listening to a lot of things. There are four chambers to the heart and some major blood vessels coming and going, so we are checking a lot of things. We move the stethoscope around the chest wall to listen closely to all of those sounds.
There should be a consistent lub-dub sound to the heart. If it’s a lub-whoosh that can indicate a heart murmur. There are specific characteristics to each heart murmur. Left-sided or right-sided can indicate which side of the heart is affected and if there are other markers for heart failure this can have drastically different effects on the body. Certain heart murmurs are more cranial in the chest, indicating possible heart defects that often start at birth.
The heart can have arrhythmias too. Basically, that means that the heart rate is erratic. Different arrhythmias mean different things. Many dogs naturally have what’s called a sinus arrhythmia. This means the heart rate goes up when they breathe in, goes down when they breathe out. It doesn’t necessarily indicated disease, but it is noteworthy. So, for dogs that are normally noted in their medical records to have a normal rate and rhythm, to have a sinus arrhythmia may indicate underlying disease, and vice versa. A dog that normally has a sinus arrhythmia but now has a steady rate and rhythm that is higher than normal may indicate that dog is in pain.
Arrhythmias and heart murmurs are definitely cause for concern and can indicate many diseases. Arrhythmias can be secondary to toxicities or medications that may be causing an adverse side effect. There can also be primary arrhythmias that need to be investigated by either an ECG test and/or a consultation with a cardiologist. Medications will often keep them under control but it needs to be fully diagnosed because different medications treat different arrhythmias.
Many many pets and many people even have heart murmurs that are ‘innocent.’ This means that there is a defect in one of the valves inside the heart, making the heart ‘leaky.’ Just because there’s a heart murmur does not mean that the heart is failing. We will make a note of the heart murmur and rate the severity of it on a scale of one to six. A Grade 1 heart murmur is very faint and can only be heard with a quiet room, a cooperative patient and a good stethoscope. A Grade 6 heart murmur can be heard from across the room without a stethoscope and sounds like a washing machine. Grade 1 and 2 heart murmurs are definitely in need of monitoring but are not necessarily a problem. Grade 5 and 6 are basically heart failure.