# Tricuspid Regurgitation in Dogs: Causes and Care Tricuspid regurgitation in dogs means the valve between the right upper and lower heart chambers does not close tightly, so blood leaks backward instead of flowing forward to the lungs. It can be mild and harmless for years, or it can progress to right-sided heart failure that needs daily medication. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Tricuspid regurgitation (TR) is a leaky tricuspid valve on the right side of the heart. A veterinarian usually first suspects it when they hear a heart murmur. - The most common cause in older dogs is myxomatous degeneration, the same valve wear-and-tear process that causes mitral valve disease [1]. - Many dogs with mild TR have no symptoms and need only periodic checkups. Dogs with advanced TR may develop a swollen belly, fainting, or trouble breathing. - Diagnosis relies on echocardiography (heart ultrasound), which shows how severe the leak is and whether the heart is enlarging. - Treatment focuses on managing congestion and the underlying cause. There is no pill that repairs the valve itself. ## What Tricuspid Regurgitation Means in Plain Words Your dog's heart has four chambers. The tricuspid valve sits between the right atrium (upper chamber) and the right ventricle (lower chamber). When the heart relaxes, this valve opens so blood can fill the ventricle. When the heart pumps, the valve should snap shut so blood only exits toward the lungs. With tricuspid regurgitation, that seal is imperfect. Some blood squirts backward into the right atrium with every beat. A small leak is often trivial. A large leak forces the right atrium and right ventricle to work harder and enlarge over time. Eventually, pressure backs up into the veins that drain the body, and fluid can leak into the abdomen or, less often, the chest [2]. Veterinarians describe TR as primary when the valve itself is malformed or damaged, and secondary when a normal valve leaks because the right ventricle or the valve ring has stretched. Secondary TR is common when pulmonary hypertension (high blood pressure in the lung arteries) pushes back on the right side of the heart [3]. ## Signs Owners Notice Mild tricuspid regurgitation usually causes no visible signs at all. The first clue is often a murmur heard during a routine exam. When TR becomes significant, signs reflect blood damming up in the body instead of flowing forward properly [2]. Watch for: - A swollen or tight belly (ascites), which is the most telltale sign of right-sided congestion - Tiring quickly on walks or lagging behind - Weakness or fainting - A soft cough or heavier breathing, especially if pulmonary hypertension is also present - A bluish tinge to the gums in severe cases, which reflects low oxygen in the blood [2] - Exercise intolerance, which was the presenting complaint in a dog with severe congenital tricuspid valve dysplasia [4] Some dogs with right-sided heart disease also have a distended jugular vein in the neck or fluid buildup in the legs, though this is less obvious in dogs than in people. If your dog has a cough and you are not sure whether it points to heart disease, see [How to Tell If Your Dog's Cough Is Heart Disease or Something Else](/knowledge/veterinary-medicine/senior-and-chronic-care/dog-cough-heart-disease-or-other). ## Causes and Risk Factors ### Myxomatous valve degeneration This is the leading cause of tricuspid regurgitation in older dogs. The fibrous layer of the valve breaks down, the leaflets thicken and prolapse, and the anchoring cords (chordae tendineae) weaken and can rupture [1]. Myxomatous degenerative valve disease accounts for about 75% of cardiovascular disease in dogs. About 60% of affected dogs have only the mitral valve involved, while roughly 30% have lesions in both the mitral and tricuspid valves [1]. Because the mitral valve is affected far more often, many dogs with tricuspid regurgitation also have mitral valve disease. If your dog has been diagnosed with the mitral side first, see [Canine Mitral Valve Disease: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/canine-mitral-valve-disease-diagnosis-management). ### Breed predisposition The exact cause of myxomatous degeneration is unknown, but in Cavalier King Charles Spaniels and Dachshunds it is an inherited trait [1]. Other small and medium breeds are commonly affected as well. ### Congenital tricuspid valve dysplasia Some dogs are born with a malformed tricuspid valve. Tricuspid valve dysplasia involves abnormal valve shape, tethered leaflets, poor leaflet closure, and enlargement of the right atrium and ventricle [4]. A young Labrador Retriever with severe dysplasia presented with a loud murmur and exercise intolerance [4]. ### Pulmonary hypertension and other secondary causes Any condition that raises pressure in the lung arteries can stretch the right ventricle and the tricuspid valve ring, producing a leak even though the valve leaflets are normal [3]. In dogs, one recognized trigger is infection with the parasite Angiostrongylus vasorum, which has been linked to pulmonary hypertension [5]. In that study, dogs often arrived in respiratory distress, and the measured tricuspid regurgitation pressure gradient resolved in some dogs after treatment [5]. Rare causes exist too. A hydatid cyst in the right ventricle has been reported to obstruct the tricuspid valve and cause right heart failure, but this is extremely uncommon and was described in a human patient [6]. ### A note on other heart diseases Tricuspid regurgitation can also appear alongside diseases that weaken the heart muscle, such as [Dilated Cardiomyopathy in Dogs](/knowledge/veterinary-medicine/clinical-methods/dilated-cardiomyopathy-in-dogs). A murmur plus a strange breathing pattern sometimes gets confused with other problems, which is why [Dog Reverse Sneezing Heart Murmur](/knowledge/veterinary-medicine/clinical-methods/dog-reverse-sneezing-heart-murmur) is worth reading if you are sorting out what you are hearing and seeing. ## How Tricuspid Regurgitation in Dogs Is Diagnosed ### Physical examination Your veterinarian listens for a murmur, checks the pulse, feels the belly for fluid, and looks at the gums and jugular veins. A murmur on the right side of the chest, heard best over the tricuspid area, raises suspicion. ### Echocardiography This is the core test. Ultrasound of the heart shows the valve's shape and motion, the size of the right atrium and ventricle, and the direction and volume of the leak. It also lets the vet measure the velocity of the regurgitant jet, which estimates the pressure difference across the valve. That measurement matters because it is used to estimate pulmonary arterial pressure. Tricuspid regurgitation peak velocity is commonly used for this purpose, but it is not always obtainable in every dog [7]. When the jet is weak or hard to align, veterinarians may use a composite scoring approach based on several echocardiographic features to estimate pulmonary hypertension severity [7]. ### Other tests - Chest X-rays to look at heart silhouette and lung patterns - Blood work, including a heartworm test and, when relevant, testing for Angiostrongylus vasorum - Electrocardiography if an arrhythmia is suspected - Blood pressure measurement ### What the numbers mean | Finding | What it suggests | |---|---| | Soft murmur, no symptoms, normal heart size | Mild disease, monitor only | | Loud murmur with right atrial or ventricular enlargement | Moderate to severe leak, closer monitoring | | High tricuspid regurgitation velocity | Possible pulmonary hypertension [7] | | Fluid in the abdomen | Right-sided congestive heart failure [2] | | Malformed, tethered leaflets in a young dog | Congenital tricuspid valve dysplasia [4] | ## Treatment Options There is no medication that reverses a degenerated valve. Treatment aims to control congestion, lower pulmonary pressures when possible, and treat any underlying cause. ### Treating the underlying cause If pulmonary hypertension from Angiostrongylus vasorum is the driver, treating the parasite can improve the pressure gradient over months to years [5]. If the cause is a systemic disease, that condition becomes the target. ### Medications for congestion and pressure When fluid accumulates, veterinarians typically use diuretics to remove it, plus other drugs chosen for the individual dog. Your veterinarian calculates every dose from your dog's weight, kidney values, and current heart function. Never adjust a cardiac medication on your own. ### Surgery Surgical repair of the tricuspid valve is uncommon in dogs and is generally limited to specialized centers. One reported approach, cone reconstruction, rebuilt the valve in a dog with severe tricuspid valve dysplasia by mobilizing the leaflets, reducing the valve ring, and reshaping the tissue into a cone-like valve [4]. This is not a routine option, and candidacy depends on the individual dog and the availability of a surgical team. ### Monitoring pulmonary hypertension Dogs with TR often need repeat echocardiograms to track pressures and chamber size. Because tricuspid regurgitation velocity is not always measurable, your cardiologist may combine several echo findings into a score to judge severity over time [7]. ## Recovery, Outlook, and Long-Term Management The outlook depends heavily on the cause and how early the problem is caught. Dogs with mild myxomatous tricuspid involvement may live normal lives for years with routine monitoring. Dogs with severe regurgitation and right-sided heart failure need lifelong medication and more frequent checkups. In the pulmonary hypertension and parasite study, some dogs survived long term after treatment, and the regurgitation pressure gradient resolved in a portion of them [5]. At home, you can help by: - Weighing your dog weekly on the same scale and logging the number. Rising weight often means fluid, not fat. - Measuring resting breathing rate while your dog sleeps. Count breaths for 30 seconds and multiply by two. - Keeping sodium intake modest and asking your vet before changing diet. - Giving medications at consistent times and never skipping doses. - Watching for a distended belly, which is a reason to call your vet promptly [2]. Some dogs with right heart strain also develop rhythm disturbances. If you notice head or body tremors that worry you, [Comprehensive Guide to Head Shaking in Dogs: Causes, Diagnostics, and Treatment](/knowledge/veterinary-medicine/symptom-guides/dog-head-shaking-master-guide) can help you decide whether it needs a visit. ## Prevention You cannot prevent myxomatous degeneration in a dog that inherited the tendency. What you can do is reduce the chance that a mild leak becomes a crisis. - Ask your veterinarian to listen carefully at every annual exam, especially in Cavalier King Charles Spaniels and Dachshunds, since inheritance is established in these breeds [1]. - Keep your dog at a healthy weight and provide regular, moderate exercise. - Use year-round parasite prevention as your veterinarian recommends, since lung parasites can contribute to pulmonary hypertension [5]. - If a murmur is found, follow through with the recommended echocardiogram instead of waiting for symptoms. - If your dog is used for breeding and comes from a breed with known valve disease, discuss screening with your veterinarian. ## Limitations and When to Contact a Veterinarian No article can tell you how serious your dog's leak is. That requires an examination and usually an echocardiogram, and every case needs a veterinarian's individual assessment. Contact a veterinarian the same day if your dog: - Has a visibly swollen or tight abdomen - Breathes faster than usual at rest, or breathes with effort - Collapses, faints, or seems weak - Refuses food or seems suddenly lethargic Go to an emergency clinic now if your dog: - Struggles to breathe, stands with elbows out, or cannot lie down - Has blue or gray gums - Collapses and does not recover quickly Schedule a routine visit if you have heard a new murmur mentioned at a previous exam, if your dog tires more easily than before, or if you want a baseline echocardiogram for a predisposed breed. ## Frequently Asked Questions ### Is tricuspid regurgitation in dogs life threatening? It can be, but many cases are mild and never shorten a dog's life. The risk rises when the leak is severe, when the right heart chambers enlarge, or when pulmonary hypertension is present. Regular monitoring lets your veterinarian catch those changes early. ### Can a leaky tricuspid valve heal on its own? A degenerated valve does not repair itself. However, when the leak is caused by a treatable condition such as a lung parasite, the pressure problem can improve with treatment and the regurgitation can become much less significant over time. ### Does my dog need surgery for this? Surgery is rarely needed and is offered only at specialized centers for selected dogs with severe congenital valve malformation. Most dogs are managed with medication and monitoring. Your veterinarian or cardiologist will tell you whether your dog is a candidate. ### Will my dog need medication forever? If your dog has only a mild leak and no symptoms, medication may not be needed at all. Once congestive heart failure develops, treatment is generally lifelong. Doses are calculated for your dog's weight and health and are adjusted as things change. ### Can I still walk my dog? Yes, in most cases. Moderate, consistent exercise is usually fine and helps with weight control. If your dog faints or tires quickly, ask your veterinarian to set an activity plan that matches your dog's heart function. ## Related Articles - [Canine Mitral Valve Disease: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/canine-mitral-valve-disease-diagnosis-management) - [Dilated Cardiomyopathy in Dogs](/knowledge/veterinary-medicine/clinical-methods/dilated-cardiomyopathy-in-dogs) - [How to Tell If Your Dog's Cough Is Heart Disease or Something Else](/knowledge/veterinary-medicine/senior-and-chronic-care/dog-cough-heart-disease-or-other) - [Dog Reverse Sneezing Heart Murmur](/knowledge/veterinary-medicine/clinical-methods/dog-reverse-sneezing-heart-murmur) - [Comprehensive Guide to Head Shaking in Dogs: Causes, Diagnostics, and Treatment](/knowledge/veterinary-medicine/symptom-guides/dog-head-shaking-master-guide) - [Why Does My Dog Have A Honking Cough](/knowledge/veterinary-medicine/symptom-guides/why-does-my-dog-have-a-honking-cough) - [Heart Murmur Treatment in Dogs: Medications and Care](/knowledge/veterinary-medicine/senior-and-chronic-care/heart-murmur-treatment-dogs) - [Heart Murmur in Dogs: Symptoms, Grades, and When to Worry](/knowledge/veterinary-medicine/symptom-guides/heart-murmur-in-dogs-symptoms) - [Enlarged Heart in Dogs: Symptoms, Causes, and Stages](/knowledge/veterinary-medicine/senior-and-chronic-care/enlarged-heart-in-dogs-symptoms) ## References 1. [Myxomatous Atrioventricular Valve Degeneration in Dogs and Cats - Circulatory System](https://www.merckvetmanual.com/circulatory-system/various-heart-diseases-in-dogs-and-cats/myxomatous-atrioventricular-valve-degeneration-in-dogs-and-cats). Merck Veterinary Manual. 2. [Heart Disease in Dogs - Dog Owners](https://www.merckvetmanual.com/dog-owners/heart-and-blood-vessel-disorders-of-dogs/heart-disease-in-dogs). Merck Veterinary Manual. 3. [Large Animal Models of Tricuspid Regurgitation: Relevance, Limitations, and Future Directions](https://pubmed.ncbi.nlm.nih.gov/42260026/). Journal of cardiovascular translational research, 2026. 4. [Cone reconstruction for severe tricuspid valve dysplasia in a dog](https://pubmed.ncbi.nlm.nih.gov/42772022/). Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology, 2026. 5. [The long-term outcome and changes in tricuspid regurgitation pressure gradient in dogs diagnosed with pulmonary hypertension and Angiostrongylus vasorum infestation](https://pubmed.ncbi.nlm.nih.gov/40579840/). The Journal of small animal practice, 2025. 6. [Hydatid cyst in the right ventricle leading to tricuspid stenosis and heart failure: a case report](https://pubmed.ncbi.nlm.nih.gov/42001156/). Journal of cardiothoracic surgery, 2026. 7. [Development and evaluation of a composite echocardiographic score for predicting pulmonary hypertension severity in dogs](https://pubmed.ncbi.nlm.nih.gov/41742574/). Journal of veterinary internal medicine, 2026. ## Further Reading - [Merck Veterinary Manual: Dog Owners](https://www.merckvetmanual.com/dog-owners) - [Cornell Richard P. Riney Canine Health Center: Canine Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)