What does a picture of a heart bring to mind to you? Love? Chocolate? Heart disease? Heartworms? I think it is clear by now that my mind travels to strange places, and for the next two weeks while others think of loving hearts I will talk about issues with pet hearts. I swear I did get invited to parties pre-corona.
We all want and hope for healthy hearts in our pets. They give their hearts to us fully and quickly, and it is our job to take care of them. The problem with heart disease in our animals is that it often goes undetected for a long time.
Our pets do not get “heart attacks” as people do, but many of them have heart disease that ultimately is fatal. Pets can have heart disease for many years before owners even know. Our pets slowly compensate and are unable to let us know if they have mild chest pain or feel slightly weak when exercising. These subtle signs are missed because as with many things, our animals can’t talk to us. Heart disease develops in pets not from the diet, but from genetic factors and simple wear and tear.
Pets still do not live long enough to get diet-related heart issues and their diets are fairly well controlled. Even our overweight pets aren’t eating a steady diet of fat. While extra weight and fat put a strain on their hearts and they have to work harder, things like atherosclerosis aren’t an issue. Some pets are born with heart disease and have it even as babies. I’ll talk about the most common types in cats and dogs, and signs to look for that may help them be diagnosed sooner.
Chronic Valvular Disease
Many heart changes in dogs are detected first as heart murmurs, which is a good reason to have a yearly exam. The most common cause of heart failure in dogs is chronic valvular disease. The valves between the sections of the heart start to wear out. They start to thicken and change so that they no longer meet in the middle. This means that they don’t snap closed efficiently. Think of a leaky valve in a car engine. This means that as the blood pumps through the heart small jets of blood get through the valve gaps and whirlpool where it isn’t supposed to.
These are sort of like worn-out rubber bands that can’t snap back properly. As the blood hits the wall of the heart where it shouldn’t, the heart starts to thicken and scar in that area. This is especially common in small breed pure-bred dogs but can happen in any dog.
Dogs also get something called dilated cardiomyopathy. With this disease, the walls of the heart become thin and the heart distends so it is larger than normal. This means that every time the heart pumps, it pumps very weakly and the blood doesn’t circulate well. We then see a shortage of oxygen to the brain and a backup of fluid in the lungs. This can present as exercise intolerance, coughing, or a distended abdomen. This is seen more commonly in large breed dogs and usually happens over time, though Great Danes and Dobermans are more likely to have this as a congenital (born with it) problem.
This is the disease that is being linked to grain-free foods that haven’t undergone long term studies. The thinking is that the things which are added in the place of grains (because carbohydrates are still an important part of diets) interfere with the absorption of a certain amino acid which is important for heart muscle integrity. Hopefully, as studies progress, we will have a clearer link. At this point even supplementing the amino acid (taurine) doesn’t seem to help, so you can’t just add more into their food. Dogs taken off these diets often can reverse the disease more drastically than the type that is caused by time or genetics. This is diagnosed with an ultrasound and diet history.
We all know how different dogs and cats are and how they like opposite things. To that end, cats get an opposite type of cardiomyopathy called hypertrophic cardiomyopathy. This means that instead of the heart walls become thin, they become very thick. This leaves less space inside the heart for blood, and the heart walls do not contract effectively. This type of heart failure can be related to hyperthyroidism. Unlike heart changes in dogs, this is not heard as easily with a stethoscope in most cases. Because of the way the heart beats, cats with HCM are more likely to develop clots that travel throughout their bodies. These can cause problems in the lungs, brain, abdominal organs or often cause hind limb paralysis.
Sometimes this disease presents as cats just not doing as well, sometimes with episodes of “panting”, or some present as an emergency with blood clots. Some of these cats will have murmurs we can hear and some we discover with increased heart rates. Unfortunately, some of these cats show no signs until they do throw a clot and become critically impaired. As with all things cat, any behavior changes can be an alert to underlying issues so it is important to get them checked out.
Some cats are born with HCM and it may go undetected, or become a problem when they first have anesthesia. Certain breeds of cats are more prone to this, and we often recommend screening these breeds before anesthesia.
There are many types of heart disease, but these are the three we see very commonly. Heart disease can result in many different signs. The underlying causes may be different, but most heart disease starts as subtle changes. Animals can become weak, develop a cough, be less tolerant of exercise, and even collapse or “pass out” for a moment. You may also see a bloated abdomen (over a few days, heart failure is not likely the cause of a big belly if your pet gets into a bag of food.) Since the heart also pumps blood to the lungs to become oxygenated before sending it to the body, fluid can build up in the lungs from ineffective pumping. Signs of this include coughing, panting, and struggling to catch their breath after simple activity.
If a murmur is heard in a pet, usually the next step is to take chest x-rays. It is ideal to get a cardiac ultrasound (or echo) on them as well. This lets us see the thickness of the heart walls at every point, the function of the valves, and how the blood flows through the different parts of the heart. In this manner, we can more easily pinpoint the exact area of compromise and treat it accordingly.
All types of heart failure can be treated with varying success. The earlier they are detected, the better chance there is of helping to prolong their life. There are medicines that help the heart beat faster, slower, or stronger. There are also medications that help regulate blood pressure changes and fluid changes that might be associated with heart failure.
If you have noticed a drastic change in activity overall or been putting off a yearly exam it might be time to have a check-up. Once heart failure is detected, it is up to us to provide the best quality of life we can. This means keeping them at a good weight, a good quality diet, and reduced-sodium (in treats, softened water, etc.) Your veterinarian can help direct you towards helpful changes once an issue is detected.