Heart disease in dogs is most often due to the heart's valves becoming distorted until they can't close properly. When the heart then beats, some of the blood is pumped forwards (which is good) and some leaks back through the valve (not good at all), creating turbulence in the blood flow. With a stethoscope, this makes a sound known as a murmur.
There are various stages of this type of heart disease: the task for us at the Hyde Park Veterinary Centre and for you as the owner of an affected dog (and of course for the dog in question if only they knew it), is to find out which category is your beloved hound in and what we are going to do about it.
This much simplified guide is to try to help you understand where your dog might be on the scale of seriousness, and to guide you through the kind of things we might be discussing or reccommending to you
At risk breeds such as Cavalier King Charles spaniels with no current evidence of heart disease. We will advise that you do nothing at this stage, but we should make sure to check for changes to heart sound, rate and rythmn at all health checks, or at least once a year.
Dogs with a heart murmur but no symptoms or evidence of any changes to the heart shape. No medication is generally required, but at least once a year the heart size & shape should be checked either by taking an X-ray or an ultrasound scan.
There may be some benefit from nutritional supplements in the form of omega 3 fatty acids, Co-enzyme Q10, L-carnitine, L-taurine and other anti-oxidants.
Dogs with a heart murmur and Xray or ultrasound evidence of changes to the heart shape but no other heart symptoms. If there is any significant increase in the size of the left atrium chamber of the heart, drugs called ACE-inhibitors help to maintain good circulation by reducing the resistance to blood flow that develops as the heart starts to fail. We will reccommend changes to the diet mainly to reduce sodium (salt) intake, plus nutritional supplementation as above.
Dogs with a heart murmur, heart shape changes and symptoms such as breathlessness, reduced exercise ability, raised heart rate, fluid retention (oedema) in the lungs or abdomen, or changes in heart shape and/or size. A pro-BNP blood test can help to quantify the severity of the heart disease. These dogs need urgent medication with ACE-inhibitors (see above) and diuretics to help clear fluid retention. A drug called pimobendan helps increase the strength of the heart muscle whilst reducing the increased resistance to blood flow that often occurs in heart failure and spironolactone is also commonly used to help slow the rate of deterioration in heart function.
Dogs with all the above symptoms but where home management with medication is not controlling the symptoms. These dogs need urgent medical help in a clinic or hospital.
All sounds a bit alarming? Heart disease is certainly no fun and it will progress over time, together we can do a great deal to keep our patients happy and comfortable for a long as possible.