Heart disease in cats and dogs is more common than we think. New Zealand now has a cat population of around 1.41 million and 700,000 dogs. We are seeing more money being spent on our animals than ever before and with that we are diagnosing more and more problems like heart disease than we ever have been able to in the past.
Heart disease more often than not takes time to develop so quite often gets passed over as the animal ages. The specific signs associated with heart disease depends on the side of the heart it occurs on.
Left sided heart disease affects the lungs of the animal. Blood gets passed from the right side of the heart to the left side of the heart through the lungs where it picks up oxygen and releases carbon dioxide. The heart works by using valves to stop fluid flowing back the direction it came. When the valve in the left aorta stops working blood floods back into the lungs. The lung responds to this extra fluid by forcing the body to cough it up.
So left sided heart disease presents itself as a cough. The cough is noticed after the dog has been asleep so early in the morning or after a snooze is when the cough is heard. If left to develop you will also get exercise intolerance and muscle wastage.
Right sided heart disease affects the abdomen of the dog. The oxygenated blood previously mentioned gets pumped from the left ventricle full of oxygen all over the body supplying all the muscles and organs with oxygen then gets filtered through the liver and pumped into the right aorta depleted of oxygen and needing to get rid of CO2. When there is a problem with the right side of the heart, blood floods back into the liver and with nowhere to go it escapes into the abdomen.
So right sided heart disease will present with a dog with a bloated tummy and depending on how much fluid is in the abdomen can also affect the intestines causing diarrhea/constipation. Arthritic dogs with abdomens full of fluid will struggle to get up and eventually the fluid will press on the diaphragm making breathing difficult. Again as above exercise levels will decrease and muscle wastage occurs which leaves the classic appearance of a skinny dog with a bloated tummy.
In other cases you will get both sides of the heart affected leading to a mixture of signs.
Diagnosis is a lot easier in dogs than cats as murmurs are more easily heard in dogs than cats. Diagnosis can also be made with xrays that show enlargement of the heart. The best method for diagnosing leaky valves is with ultrasound. Where you have suspicions of heart disease and especially for cats a blood test for NT-ProBNP DNA can help make early diagnosis. There is even a simple test of counting the number of breaths the animal takes when it is asleep that an owner can use to gauge if heart disease is getting worse or if medication is working.
Treatment of heart disease is not too dissimilar to in human medicine and involves removing excess fluids with diuretics and trying to increase the ability of the heart muscle to contract. If diagnosis is made early then animals can live normal happy lives. Where diagnosis is delayed even in severe cases medication can vastly improve quality of life for the remainder of the pets’ life.
If you have any concerns over your pet's health please contact us at Far North Vets and Pets.