Your Guide to Congestive Heart Failure in Dogs

By Dr. Laura Pritzker

Hearing that your dog has heart disease or congestive heart failure (CHF) can be a worrying time. Although congestive heart failure is a serious condition, with early diagnosis and treatment, dogs can live a happy life for many months, and even years. Read on to find out more.

What Is Congestive Heart Failure?

Congestive heart failure occurs when heart disease progresses to the point where the heart can’t pump blood effectively enough anymore. As a result, fluid builds up in the lungs and other parts of the body (this is called congestion).

In some dogs, heart disease will gradually get worse over time, to the point where heart failure eventually develops. Treating some dogs before the onset of clinical symptoms will help them stay symptom-free for longer, enabling them to enjoy life to the fullest. Early diagnosis of heart disease and regular, proactive monitoring are therefore the keys to the best long-term outcomes.

In this article we’ll explore the causes of heart failure, the signs to look for, and how you can take proactive steps to keep your dog happy for as long as possible.

Causes of Congestive Heart Failure

Heart disease is common, affecting around 1 out of every 10 dogs seen in veterinary clinics.^1,2 There are several different types of heart disease that can cause heart failure, but 9 out of 10 dogs with heart disease have 1 of just 2 diseases.³

The 2 most common causes of heart failure in dogs are:

Mitral valve disease
Dilated cardiomyopathy

Mitral Valve Disease

Mitral valve disease is by far the most common cause of heart failure in dogs. Around 75% of all heart disease in dogs seen in practice is mitral valve disease (MVD) or myxomatous mitral valve disease (MMVD).^2,4,5 MMVD is most common in small and medium dog breeds, especially as they get older. The first sign tends to be a heart murmur, normally picked up by a veterinarian at a routine health check. The mitral valve normally seals to stop blood flowing backward when the heart pumps. In mitral valve disease the valve slowly becomes misshapen over time, eventually becoming leaky. When the heart pumps, this leaky valve allows some blood to flow backward, so the heart has to work harder to be as effective.

Mitral Valve Disease Facts

Causes 75% of heart disease in dogs seen in practice
Affects middle-aged and older, small and medium breed dogs
Causes a leaky heart valve
First sign is a heart murmur
Cavalier King Charles Spaniel
Chihuahua
Dachshund
Maltese
Miniature Poodle
Miniature Schnauzer
Shih Tzu

Dog Breeds Predisposed to MMVD

Cavalier King Charles Spaniel
Chihuahua
Dachshund
Maltese
Miniature Poodle
Miniature Schnauzer
Shih Tzu

Dilated Cardiomyopathy (DCM)

The heart of a dog with DCM becomes stretched and abnormally thin, which leads to an enlarged heart size and weakened muscle contractions. These changes in the heart muscle result in reduced blood flow to the body. Dilated cardiomyopathy is most common in large and giant breed dogs. Unlike heart valve disease, the signs of dilated cardiomyopathy can occur suddenly, so regular heart health checks are important to pick it up early.

Dilated Cardiomyopathy Facts

The second most common heart disease in dogs
Affects large and giant breed dogs
Causes the heart muscle to become weak
Signs can appear suddenly
Cocker Spaniel
Doberman Pinscher
Golden Retriever
Great Dane
Irish Wolfhound
Labrador Retriever

Dog Breeds Predisposed to DCM

Cocker Spaniel
Doberman Pinscher
Golden Retriever
Great Dane
Irish Wolfhound
Labrador Retriever

Signs of Heart Failure

In the early stages of heart failure, you may not notice any signs, but as it progresses, they will become more obvious.

The most common signs of heart failure in dogs are:

Coughing
Difficulty breathing
Rapid breathing
Difficulty exercising
Weakness or lethargy (tiredness)
Fainting episodes or collapse
Gray or blue gums
Swollen belly

Sometimes these signs are subtle and can be mistaken for a dog that is just getting older and “slowing down.” If you notice any of these signs, it is best to get your dog checked by a veterinarian to make sure.

Diagnosing Heart Failure

Tests

If your veterinarian suspects heart failure, they’ll recommend some tests to confirm their diagnosis and identify which heart disease is causing the problem.

These tests could include:

Chest X-rays to see the heart size and shape, blood vessels, and lungs
Listening to your dog’s heart with a stethoscope to assess heart rate and rhythm to detect if a murmur is present
Blood and urine tests
Ultrasound to look at the inside of the heart and how well it’s working
An electrocardiogram (ECG)

Sometimes your veterinarian will recommend a referral to a veterinary cardiologist.

These tests aren’t just used to diagnose heart failure; they also provide useful information to stage heart disease before heart failure develops. This helps veterinarians decide when they should start treatment.

Many dogs with heart disease will benefit from receiving treatment before they develop heart failure.

Treatment and Prevention

Treatments

Although heart failure can’t be reversed, it can be slowed with medicines, and the symptoms of heart failure can be managed to help dogs feel better. There are 2 aims of treating a dog with heart failure:

1. Remove Excess Fluid From the Body

This is done with diuretics, such as furosemide or torsemide. Diuretics make dogs urinate more than usual, so make sure your pup has plenty of potty breaks.

2. Help the Heart Function the Best It Can

The most common medicines used for this are inodilator, angiotensin-converting enzyme (ACE inhibitors), and spironolactone. Most dogs with heart failure may be on 3-4 different medicines to keep them feeling well.

Prevention and Early Intervention

Some breeds are more at risk of heart disease than others, but there are steps that you can take to help keep your dog’s heart healthy:

Keep your pet at a healthy weight
Feed a balanced, nutritious diet
Give your dog frequent cardiac exercise
Visit your veterinarian regularly
Give regular parasite preventives
Look after your dog’s teeth (there’s a link between dental disease and cardiac disease)

Key Takeaways

Certain dog breeds are more at risk

Early diagnosis and management are crucial

Early diagnosis and management are crucial for managing heart failure and, sometimes, also delaying it.

Dogs can have a good quality of life

Treatment will involve lifelong medications, but affected dogs can have a good quality of life.

Work with your vet for treatment

Regular visits to your veterinarian are essential to diagnose heart disease early and to keep your dog happy and healthy for as long as possible.

References

1. Atkins C, Bonagura J, Ettinger S, et al. Guidelines for the diagnosis and treatment of canine chronic valvular heart disease. J Vet Intern Med. 2009;23(6):1142-1150. doi:10.1111/j.1939-1676.2009.0392.x
2. Keene BW, Atkins CE, Bonagura JD, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. J Vet Intern Med. 2019;33(3):1127-1140. doi:10.1111/jvim.15488
3. Ware WA. Cardiovascular Disease in Small Animal Medicine, Ames, IA: Blackwell Publishing Professional; 2007.
4. Lombard CW, Jöns O, Bussadori CM. Clinical efficacy of pimobendan versus benazepril for the treatment of acquired atrioventricular valvular disease in dogs. JAAHA. 2006;42(4):249-261. doi:10.5326/0420249
5. Rush JE. Chronic valvular heart disease in dogs. Proceedings from the Waltham/OSU Symposium, Small Animal Cardiology, 2002. VIN. Accessed December 16, 2022. https://www.vin.com/apputil/content/defaultadv1.aspx? meta=&pId=11149&id=3846599

DR. LAURA PRITZKER

Dr. Laura Pritzker earned a Doctor of Veterinary Medicine from the University of Minnesota College of Veterinary Medicine. Dr. Pritzker is also a co-director (and foster) of a local dog rescue in Minnesota. She has been able to further her passion in shelter/rescue medicine by completing a master’s degree in shelter medicine through the University of Florida College of Veterinary Medicine in 2023.