Cavalier King Charles Spaniel Heart Disease

Mitral Valve Disease (MVD) is something every Cavalier King Charles Spaniel parent should be familiar with. Sadly, this condition is extremely common in the Cavalier breed, but early awareness and proper management can greatly improve a Cavalier’s quality of life. In this blog, we’ll cover what MVD is, why Cavaliers are at risk, how the disease is staged, and which supplements can help support a healthy heart.
A heartfelt thank you to Lisa Davila, BS in Biomedical Science and Hospital Manager at Aggieland Animal Health Center in College Station, Texas, for helping me put together this article. Lisa has not only dedicated her career to animal health but has also been a loving mom to many Cavalier King Charles Spaniels. Her knowledge and experience are truly invaluable!

Understanding Mitral Valve Disease (MVD) in Cavaliers
Mitral Valve Disease (MVD) is a degenerative condition that affects the mitral valve of the heart. The mitral valve is responsible for ensuring blood flows properly between the left atrium and left ventricle. Over time, this valve can weaken and leak, allowing blood to flow backward into the atrium. This puts additional strain on the heart, eventually leading to heart enlargement and, in later stages, congestive heart failure (CHF).
MVD is considered a slow-progressing disease, but it varies from dog to dog. Some Cavaliers may live for years with a mild heart murmur, while others may progress more rapidly. Since MVD is so common in the breed, Cavaliers should be closely examined (cardiac auscultation) annually, to determine if they have a murmur. The presence of a murmur is often the first sign that a dog has degenerative valve disease.
Why Are Cavaliers at Risk of MVD?
Cavalier King Charles Spaniels are unfortunately predisposed to MVD. While any breed can develop valve disease, Cavalier King Charles Spaniels are at the greatest risk for developing degenerative mitral valve disease. Studies have shown that over 50% of Cavaliers develop a heart murmur by the age of 5, and by age 10, that number jumps to nearly 100%.Because MVD has a strong genetic component in Cavaliers, responsible breeding practices are essential. Responsible Cavalier King Charles Spaniel breeders ensure their breeding dogs undergo echocardiograms conducted by board-certified cardiologists. When considering a puppy, both parents should have cardiologist-issued heart clearances and be at least 2.5 years old at the time of breeding. Additionally, all four grandparents should be over the age of 5 and heart-clear. However, even with careful breeding, the risk remains high in the breed.
The Stages of MVD

MVD is typically classified into different stages based on its progression. Early detection and monitoring are crucial to managing the disease effectively.
- Stage A – Dogs at risk for MVD but without any current signs (e.g., all Cavaliers are considered Stage A at birth because of their predisposition).
- Stage B1 – A veterinarian detects a heart murmur, but there is no evidence of heart enlargement on X-rays or echocardiograms.
- Stage B2 – A heart murmur is present, and imaging confirms heart enlargement. At this stage, medication such as Vetmedin (pimobendan) is often started to help delay the onset of congestive heart failure.
- Stage C – Congestive heart failure (CHF) is present, meaning the heart can no longer compensate for the disease. Symptoms such as coughing, lethargy, and difficulty breathing may be noticeable. Medications are necessary to help manage the condition.
- Stage D – End-stage CHF, where symptoms become harder to control even with medications.
Once a dog reaches Stage B2, most cardiologists recommend starting treatment to slow disease progression. Regular checkups and echocardiograms help ensure the right treatment plan is in place.
The Truth About Grain-Free Diets and Heart Disease in Cavaliers
With all the discussion surrounding Mitral Valve Disease (MVD) in Cavaliers, you may have come across concerns about grain-free diets and their potential link to heart disease. It’s important to separate the headlines from the facts when it comes to feeding our Cavaliers the best diet for heart health.
The debate about grain-free dog food largely stems from concerns about dilated cardiomyopathy (DCM), a condition where the heart muscle weakens, leading to poor function and potential heart failure. While DCM is a serious disease, the concern over grain-free diets has often been misinterpreted. The issue isn’t necessarily the lack of grains but rather the high levels of starchy carbohydrates like peas, lentils, legumes, and potatoes that are often used as substitutes in processed grain-free kibble.
Cavaliers are already predisposed to MVD, not DCM, which is a different heart condition with different causes. However, diet still plays a critical role in supporting heart health. The best way to provide a heart-healthy diet for your Cavalier is to focus on fresh, whole foods rich in high-quality animal proteins rather than relying on highly processed kibble, whether it contains grains or not. Read more about feeding your Cavalier a fresh diet.

Dr. Karen Becker explains it best: “The problem with grain-free formulas isn’t the lack of grains. At a minimum, it’s the high level of starchy carbohydrates coupled with the extreme high-heat processing methods used to produce these diets.”
Rather than worrying about whether a diet is labeled as “grain-free,” focus on feeding a fresh, balanced diet with high-quality proteins, healthy fats, and low-glycemic vegetables. Rotating proteins and using whole-food ingredients can help ensure your Cavalier gets the nutrients they need to support a healthy heart.
If you’re unsure about your dog’s diet, seek guidance from a veterinarian with a strong background in canine nutrition, not just one who sells prescription diets in the clinic. A certified veterinary food therapist (CVFT) can be a great resource when designing a diet that supports heart health while avoiding unnecessary fillers.
A well-balanced, species-appropriate diet can play a key role in keeping your Cavalier’s heart strong and healthy for years to come.
Heart-Healthy Supplements for Cavaliers with MVD

While MVD cannot be cured, a combination of medications, lifestyle management, and supplements can help support heart function and overall well-being. Below are some key supplements that may benefit Cavaliers with or at risk for MVD:
- MCT Oil (Medium-Chain Triglycerides) – Provides an alternative energy source for the heart muscle. One recommended brand is Natural Force Organic MCT Oil (1 tsp daily with food). Before giving your Cavalier coconut oil, please read this article on MCAD in the Cavalier.
- Amino Acids (Lysine, Methionine, L-Carnitine, Taurine) – Help maintain heart muscle contractility and serve as antioxidants.
- Omega-3 Fatty Acids – Reduce inflammation, decrease clot risk, help prevent heart muscle loss, and support healthy blood pressure. Nordic Naturals Omega Pet Liquid is a high-quality option.
- Vitamin E – Acts as both an antioxidant and anti-inflammatory.
- Magnesium – Plays a crucial role in heart muscle contraction and maintaining a healthy heart rhythm.
- Coenzyme Q10 (CoQ10) – A powerful antioxidant that supports heart function. Life Extension 100 mg capsules are a great choice.
Recommended Supplement Blends
If you prefer a multi-ingredient supplement, these options are formulated specifically for heart health:
- Rx Vitamins for Pets Formula CV – Includes amino acids, magnesium, Vitamin E, CoQ10, and hawthorn berry extract (safe unless the dog is on Vetmedin).
- VetriScience Cardio Strength Capsules – Similar to the Rx Vitamins formula but without hawthorn berry extract, making it safe for all MVD stages and medications.
Recap & Common Questions About MVD in Cavaliers
Mitral Valve Disease (MVD) is a serious but manageable heart condition that affects many Cavalier King Charles Spaniels. Early detection, responsible breeding, proper veterinary care, and supportive supplements can all play a role in keeping your Cavalier’s heart as healthy as possible.
What are the early signs of MVD in Cavaliers?
The first noticeable symptom is often a heart murmur, detected during a cardiologist visit. As the disease progresses, signs can include coughing, fatigue, labored breathing, and reduced exercise tolerance.
How long can a Cavalier live with mitral valve disease?
Many Cavaliers live for years after an MVD diagnosis, especially with early detection and proper management. While every dog is different, with the right veterinary care, medications, and supplements, Cavaliers can still enjoy a good quality of life.
What are the final stages of MVD in dogs?
In the later stages, MVD leads to congestive heart failure (CHF). Symptoms include severe coughing, difficulty breathing, lethargy, fainting, and fluid buildup in the lungs or abdomen. At this stage, medication and veterinary support are essential for comfort.
How do you treat MVD in Cavaliers?
Treatment typically includes veterinary-prescribed medications to support heart function and manage symptoms. Additionally, heart-healthy supplements, such as taurine, CoQ10, and omega-3 fatty acids, can provide extra support. Feeding a fresh, species-appropriate diet may also contribute to overall heart health.
Final Thoughts
A heart-healthy fresh diet, proper weight management, and the right combination of supplements can help support your Cavalier’s heart at any stage of MVD, even before a murmur is detected. Early intervention and regular veterinary care are key to helping our beloved Cavaliers live longer, healthier lives.
A big thank you to Lisa for sharing her knowledge on this topic! If you have any questions, feel free to ask, and don’t forget to check out Lisa and Jiminy on Instagram!
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