Heart Disease and Your Pet
Heart disease is one of the more common problems we see in senior cats and dogs. There can be a variety of different kinds of heart disease, and figuring out exactly which kind your pet has is important in managing your pet's condition. We want to tell you about the common kinds of heart problems we see in pets and what treatments we recommend to give your pet the best quality of life for as long as possible. Heart disease is not a curable problem, but many pets can live for quite a long time with appropriate medication and care.
Symptoms and Diagnosis
The vast majority of pets that are diagnosed with heart disease are asymptomatic, because the heart can be diseased for a long time before clinical signs appear. A heart murmur is usually found during routine yearly exams, and this prompts us to recommend further testing to see why your pet has a heart murmur. This is the ideal way to diagnose heart disease, because there are treatments we can implement before symptoms appear that will allow the heart to function better for a longer period of time. This is just one reason why yearly exams are so important, especially in older pets.
If your pet is exhibiting any of the following symptoms, heart disease needs to be considered as a possible cause. These include:
If your pet is exhibiting any of the following symptoms, heart disease needs to be considered as a possible cause. These include:
- Coughing (dry, moist, or bloody foam)
- Excessive panting, blue gums, or trouble breathing
- Weakness or exercise intolerance
- Weight loss
- Fainting
- Abdominal enlargement
- Chest x-rays: This will allow us to see the heart from two different angles, and this can give us a clue as to what part of the heart is enlarged or diseased, and will also give us a look at the lungs to see if there is any indication of heart failure or respiratory disease.
- ECG: We perform this test to look for any arrhythmias that could suggest different types of heart disease.
- Echocardiogram: This is an ultrasound of the heart, and is necessary to fully diagnose your pet's heart condition. X-rays can only give us a look at the silhouette of the heart, but echocardiograms allow us to see inside the heart. This is helpful in choosing what treatment is right for your pet.
- NT-proBNP: This is a blood test that looks for elevations in a certain enzyme that only becomes high with damage to the heart. In cases where there isn't a clear indicator of heart disease, this test can be run because it will tell us if your pet's symptoms are primarily heart or lung related. It is also a good way to monitor heart disease that is asymptomatic, because a rise in this enzyme usually precedes the onset of clinical signs.
- Bloodwork: Routine bloodwork can be helpful if there is suspicion of an infection or metabolic cause of your pet's heart disease. Thyroid testing in cats is commonly performed because hyperthyroidism is linked to development of heart disease in cats.
Types of Heart Disease We Commonly See
There are certain types of heart disease that commonly affect different breeds, sizes, and ages of dogs and cats. Below is a list of the common ones we see and treat. Please remember that just because your pet is predisposed to a certain type of heart disease, that doesn't mean that is the type he or she will get, so performing the necessary testing is still needed.
Heartworm Disease
This is one of the most common reasons we see heart disease in dogs and cats in Texas. Heartworms live in the right side of the heart and the pulmonary artery that goes from the heart to the lungs. They cause inflammation and over time, if untreated, will eventually cause heart failure. This is why dogs and cats need to be on a heartworm preventative year-round in Texas. For more information on heartworm disease, please read about it on our website! Heartworms can affect any age and any breed of dog and cat, and indoor cats and dogs have just as high a risk for contracting heartworms as outdoor pets!
Mitral CVD (chronic valvular disease)
The mitral valve connects the two chambers on the left side of the heart. When the heart beats, the two flaps of the mitral valve close so no blood can flow backwards between the two chambers. This valve sometimes undergoes changes that prevent the two valves from closing completely, and allows blood to flow backwards through the heart (this turbulent flow causes the murmur we hear). Over time, the pressure builds up in the heart and the heart muscle stretches and weakens, and eventually heart failure occurs. This type of heart disease is common in middle aged to older small and toy breed dogs.
HCM (hypertrophic cardiomyopathy)
This occurs when the heart muscle has to work harder to move blood through the heart and out into the body. The muscle hypertrophies (or thickens) and then cannot effectively beat, causing heart failure. This is the most common type of heart disease in cats. Domestic Shorthair Cats are the most common breed diagnosed with HCM, though Maine Coons, Persians, and American Shorthairs are also predisposed. Other causes that need to be considered for thickened heart muscles include high blood pressure, hyperthyroidism and congenital problems with the aorta.
DCM (dilated cardiomyopathy)
This occurs when the heart muscle weakens and stretches. Over time, the muscle becomes weaker and cannot pump blood out to the body as well, and heart failure occurs. Large and giant breed dogs are more commonly affected, especially the Doberman Pinscher, Great Dane, Boxer and Newfoundland. Though genetics is likely the most common cause of DCM, there are others, and these include nutritional deficiencies of taurine and L-carnitine (most maintenance dog food diets have these supplemented in - the problem occurs with homemade diets and vegetarian diets), toxins, infectious causes such as Chagas Disease, and occasionally puppies that survive Parvovirus can develop this heart condition.
Other Causes
There are many other less common heart conditions that present to us, including puppy murmurs (these are usually congenital problems that need surgery to correct them), endocarditis (infectious plaque on the heart valves), heart tumors, and more.
Heartworm Disease
This is one of the most common reasons we see heart disease in dogs and cats in Texas. Heartworms live in the right side of the heart and the pulmonary artery that goes from the heart to the lungs. They cause inflammation and over time, if untreated, will eventually cause heart failure. This is why dogs and cats need to be on a heartworm preventative year-round in Texas. For more information on heartworm disease, please read about it on our website! Heartworms can affect any age and any breed of dog and cat, and indoor cats and dogs have just as high a risk for contracting heartworms as outdoor pets!
Mitral CVD (chronic valvular disease)
The mitral valve connects the two chambers on the left side of the heart. When the heart beats, the two flaps of the mitral valve close so no blood can flow backwards between the two chambers. This valve sometimes undergoes changes that prevent the two valves from closing completely, and allows blood to flow backwards through the heart (this turbulent flow causes the murmur we hear). Over time, the pressure builds up in the heart and the heart muscle stretches and weakens, and eventually heart failure occurs. This type of heart disease is common in middle aged to older small and toy breed dogs.
HCM (hypertrophic cardiomyopathy)
This occurs when the heart muscle has to work harder to move blood through the heart and out into the body. The muscle hypertrophies (or thickens) and then cannot effectively beat, causing heart failure. This is the most common type of heart disease in cats. Domestic Shorthair Cats are the most common breed diagnosed with HCM, though Maine Coons, Persians, and American Shorthairs are also predisposed. Other causes that need to be considered for thickened heart muscles include high blood pressure, hyperthyroidism and congenital problems with the aorta.
DCM (dilated cardiomyopathy)
This occurs when the heart muscle weakens and stretches. Over time, the muscle becomes weaker and cannot pump blood out to the body as well, and heart failure occurs. Large and giant breed dogs are more commonly affected, especially the Doberman Pinscher, Great Dane, Boxer and Newfoundland. Though genetics is likely the most common cause of DCM, there are others, and these include nutritional deficiencies of taurine and L-carnitine (most maintenance dog food diets have these supplemented in - the problem occurs with homemade diets and vegetarian diets), toxins, infectious causes such as Chagas Disease, and occasionally puppies that survive Parvovirus can develop this heart condition.
Other Causes
There are many other less common heart conditions that present to us, including puppy murmurs (these are usually congenital problems that need surgery to correct them), endocarditis (infectious plaque on the heart valves), heart tumors, and more.
My Pet Has Been Diagnosed With a Heart Condition - What Now?
Once a diagnosis is made, then treatment and monitoring can begin. There are different treatments for each type of heart condition, so it is necessary to get a diagnosis before starting treatment.
Asymptomatic Heart Disease
Unfortunately, some dogs and cats present to us already in heart failure. These pets are usually having trouble breathing and are critically ill. At this point, emergency treatment is usually symptomatic until we can identify the cause. The emergency treatments we commonly give for dogs and cats in heart failure are oxygen therapy and intravenous diuretics. Once we get your pet stabilized, then treatments can continue at home. Diuretics are almost always sent home and your pet will take them for the rest of their life.
Asymptomatic Heart Disease
- Diet change - we will always recommend a diet change for your pet if there is evidence of heart disease. High salt diets will increase the volume of blood within the heart, and cause if to work harder to pump that excess blood out of the heart to the body. This new diet will be lower in sodium to reduce this workload on the heart.
- Treating underlying conditions - any hyperthyroidism, high blood pressure, heartworm disease, infections, or other problems need to be addressed immediately so that we can hopefully stop or delay the progression of your pet's heart disease. In addition, pets with heart disease need routine dental cleanings because bacteria and tartar that build up on the teeth can pose a danger for infection in already-diseased hearts.
- Monitoring - many pets with low grade heart disease only need a diet change as initial treatment. We recommend chest x-rays at least every 6 months to monitor your pet's heart condition. We may also recommend monitoring NT-proBNP levels to see when your pet's heart disease is worsening. We will add in medications where appropriate based on the results of the tests.
Unfortunately, some dogs and cats present to us already in heart failure. These pets are usually having trouble breathing and are critically ill. At this point, emergency treatment is usually symptomatic until we can identify the cause. The emergency treatments we commonly give for dogs and cats in heart failure are oxygen therapy and intravenous diuretics. Once we get your pet stabilized, then treatments can continue at home. Diuretics are almost always sent home and your pet will take them for the rest of their life.
Prognosis
The prognosis for your pet will depend entirely on what type of heart disease is present, what stage it is in, and what the underlying causes of it are. Pets that present in heart failure ultimately have poorer long-term prognoses because of the advanced state of their heart disease. Dogs and cats in heart failure from heartworm disease have very poor prognoses. Many dogs with asymptomatic Mitral CVD can live for years with appropriate monitoring and treatment. The bottom line is early diagnosis and treatment will help increase both the quality and length of your pet's life, and though heart disease is not a curable problem, often it can be managed well for months to years.