LOVE YOUR PET
If the ticker ain’t working, the body suffers.
The heart can best be described as a pump. If there is no blockage, or back-flow, there will be no shortage, or flooding.
The best place to start is probably by looking at how a healthy heart works. Blood full of oxygen from the lungs enters the heart via the pulmonary veins into the left atrium. Blood flows from here through the mitral valves into biggest heart chamber, the left ventricle. The big fat left ventricle pumps a large volume of blood through the semilunar valves into the aorta. Keep in mind that all these valves are one-way valves. Leaking will cause back-flow of blood, with resulting “flooding” at the back, and not enough blood going forward.
Now the body uses the oxygen from the blood. Oxygen-poor blood returns to the heart via the vena cava into the right atrium. From the right atrium, it flows through the tricuspid valve into the right ventricle. The right ventricle pumps blood through the pulmonary valves and the pulmonary artery back in the lungs where it can receive oxygen again. And so the never-ending cycle goes.
The most common heart condition in small breed older dogs is
The mitral valves sit between the left atrium and the left ventricle. Remember they are suppose to be one-way. When they are abnormally shaped and not sealing properly, blood flows back into the small left atrium when the big ventricle contracts to pump blood through the aorta. This cause blood to build up in the left atrium and the thin-walled atrium blows up like a balloon.
It also causes that insufficient blood enters the aorta and the body feels “faint”.
Because there is also not enough room in the left atrium to receive all the blood from the lungs, blood starts to “pool” in the lungs, causing “flooding”, or pulmonary oedema.
This condition is usually hereditary or genetic, especially in the Cavalier King Charles Spaniel, but it can also be caused by bacteria (bacterial endocarditis), especially due to bad teeth, and, rarely, a fungal infection.
DILATED CARDIOMYOPATHY (DCM) is a condition we see mostly in larger breed dogs like the Doberman, although the Spaniel is also a breed that is prone to it. In this condition, the big fat left ventricle’s muscle becomes thin and the chamber size itself enlarges. The ventricle cannot contract as well as it should, leading to less blood being pumped into the aorta and the rest of the body, and more and more blood pooling in the ventricle. It is typically a rapidly progressing disease. “The silent killer” it is often referred to, and it carries a poor prognosis. Fortunately there is a very good treatment licensed for dogs with this condition. But as it is often diagnosed in its later stages, the prognosis is usually still unfavourable.
In the olden days, DCM was more common due to dog food with inadequate taurine levels. Nowadays if your doggy is on a good diet, taurine deficiency is highly unlikely.
The most common heart condition in cats is
It is almost the opposite of DCM. The ventricle muscles grows thicker and fatter, until there is very little space inside the heart chambers. The heart does not relax properly to receive blood, and once again the “pooling” of blood in the atrium causes it to inflate like a balloon. How big the atrium is, is often used as indicator if treatment in necessary.
HCM is often called “the silent killer” in cats. It is not always possible to suspect it on clinical examination only.
These three conditions are not the only culprits that can cause heart disease. But they are the most common ones. Others to mention includes aortic stenosis, pulmonary stenosis, ventricular and atrial septal defects (a “hole” in the heart), and many other congenital conditions (birth defects).
Signs to look out for will include, in a dog, coughing and exercise intolerance, and in a cat, fast or open-mouth breathing, and pale or blueish gums.
During a routine consultation, your vet might pick up a heart murmur. This does not necessarily mean that your furry friend is in trouble. Many animals live happy, long lives without any treatment. But it is definitely something you would like to check regularly.
Happy Valentines month! May the love of your life live with a happy, healthy heart, a skip in his step, and a waggy tail.