Nibbles and Bits - October 2008

Last month, we discussed some of the types of heart disease that older animals get. However, it is not just our geriatric pets that can have heart problems. Younger dogs and cats can also have cardiac issues.

Just like human infants, puppies and kittens can be born with heart problems. These are called congenital heart defects. Not all congenital problems are hereditary although some are. The heart related problems pets are born with arise from a problem in the heart’s development while the puppy or kitten is still in the uterus. While still in the womb, the fetus gets oxygen from the placenta since it obviously can’t breathe. Because the heart doesn’t need to get oxygen from the lungs, there are holes and extra pathways in between the left and right sides of the heart so blood can flow through as a shortcut. These holes should close just before or after birth. If they don’t, they will create a murmur that can be heard with a stethoscope. Many of these holes will eventually close or become so small that they do not cause any problems. However, if they are large, they can cause blood to flow “backwards” through the heart, from left to right and that will eventually cause problems.

Another type of congenital heart problem is an outflow obstruction. This is from a narrowing of one of the blood vessels leaving the heart- either the pulmonary artery (going to the lungs) or the aorta (going to the body). Because the blood is being pushed through a narrower tube than normal, the heart has to work extra hard. This also creates a murmur that we can hear. Part of the new puppy and kitten checkups involves our listening to the heart to make sure we don’t hear any murmurs that could indicate a problem.

Not all heart problems we see in young animals are present at birth. The main one we see is Dilated Cardiomyopathy (DCM), which we addressed some last month. It is most common in Dobermans, Great Danes, Boxers, Bulldogs and other large breeds as well. In this disease, the heart becomes enlarged because the muscle thins and stretches and becomes weak so the heart can no longer pump blood efficiently. Many of these dogs do not have a murmur, but they can get irregular heartbeats (called arrhythmias). Cats can also get DCM, which is most commonly seen in young male cats. Years ago, it used to be more common but it was then discovered that cats needed an amino acid called taurine in their diet. When cat food makers started adding it to the foods, the incidence of DCM in cats decreased.

Luckily, heart disease is not common in young animals, but if you have any concerns that your younger (or older) pet seems to tire easily or gets out of breath, we should do a physical exam right away to find out the problem and start treatment.