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What is Heart Valve Regurgitation (Mitral/Tricuspid)?

The heart is comprised of four chambers. There are the atria and the ventricles, which are both responsible for allowing blood to flow. Two chambers, the atria, are above the other two, the ventricles. In addition to being divided from top to bottom, it is also divided from left to right. A valve, which only goes one way, is located in each chamber. It opens up to allow blood to flow into the chamber and then closes so the blood cannot “backflow” out, or regurgitate. When these valves do not work properly, it causes fluid to accumulate in the lungs because of the extreme amount of pressure and volume. 

The mitral valve is situated between the left ventricle and left atrium, and the tricuspid valve is situated on the other side of the heart amongst the right ventricle and right atrium. Both of these valves are known, together, as the atrioventricular valves, since both of them are situated between the atria and ventricles on either side of the heart.

Mitral/tricuspid regurgitation in dogs is a heart disease in which the valves of the heart do not function properly. The valves do not seal when they close, which causes blood to flow backwards into the previous chamber of the heart.

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Symptoms of Heart Valve Regurgitation (Mitral/Tricuspid) in Dogs

If your dog has mitral/tricuspid regurgitation, he will experience symptoms that are mild to severe. These symptoms may be similar to symptoms of other illnesses, so a veterinary diagnosis is necessary to rule out other conditions. Symptoms may include:

  • Intolerance to exercise
  • Coughing
  • Breathing difficulties
  • Rapid breathing
  • Weakness
  • Collapse


This disease is predisposed and occurs in certain dog breeds more commonly than others. Types of dog breeds that are most affected include:

  • Miniature Poodle
  • Chihuahuas
  • Cocker Spaniels
  • Dachshunds
  • Pomeranians
  • Miniature Schnauzers
  • Shih Tzus
  • Maltese
  • Cavalier King Charles Spaniels
  • Whippets

Causes of Heart Valve Regurgitation (Mitral/Tricuspid) in Dogs

This disease is genetic, but also has specific causes, especially in older dogs. Causes may include:

  • The valve, made of elastic and collagen, weaken
  • The spongiosa, which makes up the valve as well, becomes thicker
  • The newly thickened valve has difficulty staying closed or does not close correctly
  • The valve leaks, causing blood flow to reverse back into the previous chamber

Diagnosis of Heart Valve Regurgitation (Mitral/Tricuspid) in Dogs

If your dog is showing symptoms of valve regurgitation, make an appointment with your veterinarian. Once you arrive at your appointment, the veterinarian will take a closer look, ask specific questions about his symptoms, and perform a complete physical examination. The primary examination will consist of a urinalysis, blood testing, and a biochemistry profile.

Your veterinarian, upon receiving results, will then perform other tests which are specific to the cardiovascular system of your dog. Your dog will more than likely have a noticeable heart murmur which the veterinarian will be able to hear with a stethoscope. The medical professional may then conduct a radiography to take a closer look at the heart and lungs. The veterinarian may observe fluid in the lungs as well the size of the heart; valve regurgitation can cause the heart to swell.  Another tool your veterinarian may use to help further diagnose mitral/tricuspid regurgitation is an echocardiography. This is used to closely examine the valves of the heart and also the blood flow. This will show if any regurgitation is occurring. 

If there is a high level of regurgitation present, your veterinarian may perform a specific blood test, referred to as NT-proBNP, which can identify heart failure. Your veterinarian may also order other tests to help specify any other possible diagnoses if he feels the need to do so. These tests may allow the medical professional to check for other conditions, so if your dog needs specific medications to treat his heart condition, they will not interfere with any other possible abnormalities.

Treatment of Heart Valve Regurgitation (Mitral/Tricuspid) in Dogs

Once your dog is diagnosed with mitral/tricuspid valve regurgitation, there are a few treatment options your veterinarian will explain to you. Treatment options may include:


There are several different types of drugs which are used to effectively treat this disease. Your veterinarian will choose the proper drug according to your dog’s overall health, age, and heart condition. Your veterinarian may prescribe diuretics, vasodilators, or other medications to focus on specific issues your dog may be having, such as high blood pressure.


Your veterinarian will monitor your dog and possibly keep him overnight for further observation. He will also want to see your dog for repeated visits to perform the tests once again to check the effectiveness of the medication he prescribed. He may need to adjust the medication or try another if your dog is not responding after a few weeks.

Recovery of Heart Valve Regurgitation (Mitral/Tricuspid) in Dogs

Unfortunately, there is no cure for this disease. It can be controlled by medication and lifestyle changes. Your veterinarian will give you advice on any lifestyle changes, such as the prevention of overexertion, if he feels it is necessary. 

The prognosis of your dog’s condition depends on the severity of his disease. Your veterinarian will explain to you a more in-depth prediction of his prognosis; some dogs with this disease live a full life while others live less than a year. The diagnosis of your dog’s specific condition will give you more understanding of the stage of his illness. 

Be sure to follow your veterinarian’s advice on the administration of the medication, and to keep all follow-up appointments. Closely monitor your companion, and if you see signs of discomfort or any new symptoms, do not hesitate to call your veterinarian.

Heart Valve Regurgitation (Mitral/Tricuspid) Questions and Advice from Veterinary Professionals

Cocker Spaniel
10 Years
Moderate condition
0 found helpful
Moderate condition

Has Symptoms

fluids in lungs


I have a cocket spaneil who is 10 and has recently been diagnosed with Mitral Valve requrgitation and cardiac arrhythmia. He also had fluid detected in his lungs ruled out in an x ray and echo. Hes had a terrible cough and for almost a year now which has come and gone. My previous vet never diagnosed this and kept making it seem like it was a seasonal allergy, however changing his vet recently we ruled out the problem. His cough is pretty severe but only while he moved around too much. when he goes for a walk he seems fine but these are ofcourse limited too. weve been advised to give him Envas 2.5 along with cod liver oil. What I want to know is - is there any other cure or treatment for this and in what stage would you say hes in?

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3320 Recommendations
Without examining Rex I cannot confirm any diagnosis or say what stage he is in, I also cannot prescribe any prescription medications or second guess the diagnosis made by a Veterinarian during an in person examination. If you are having concerns about the diagnosis, I would recommend visiting another Veterinarian in your area for another opinion to shed more light on Rex’s condition if you have concerns. Regards Dr Callum Turner DVM

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Jack Russell Terrier
12 Years
Moderate condition
0 found helpful
Moderate condition

Has Symptoms


Medication Used


We have a Jack Russell who will be 12 in April. Friday he was diagnosed with Sick Sinus Syndrome as well as Mitral Valve Regurgitation. The vet has put him onto 5mg cardisure tablets which she said are to help both conditions. So far, imaging doesn’t show any fluid in the lungs but the murmur of the flowback is there. We are considering taking him to a cardiologist for a pacemaker assessment but obviously we are also thinking of his welfare as much as we can. Is there a cut off age for considering a pacemaker in his breed? Would it be putting him through too much stress? And will it help the mitral valve or is that contraindicative? The only symptoms he has was a cough that started a Christmas and has been very intermittent and until he collapsed last week. All other bloods are coming up normal.

Dr. Michele King, DVM
Dr. Michele King, DVM
1611 Recommendations
Thank you for your email. It seems positive that he is responding to his medications. Given his diagnoses, I think a consultation with a cardiologist would be a great idea - they'll be able to give you a better idea as to how stressful the surgery is for him, whether it would help with his stage of heart disease and his general health status, as well as if it is actually the best treatment for him at this point. I hope that everything goes well for him.

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12 Years
Mild condition
0 found helpful
Mild condition

Has Symptoms


Hi I have a 12 year old Chihuahua who was recently diagnosed with mitral valve reurgitation (left side heart failure). The x-rays showed no fluid in the lungs but the ultrasound found some fluid in the heart sac. I first took my dog in for a cough that would not go away. She is now on 3 medications. She has never really has labored breathing like I've seen with other dogs with CHF. And she acts pretty normal. Her really only symptom is the coughing. Is it possible she might have been wrongly diagnosed? Everything I have seen is with dogs who appear to have a hard time breathing.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3320 Recommendations
Generally, the cough associated with congestive heart failure is due to fluid in or around the lungs, if the lungs are clear I would be looking into ruling out other causes of coughing like infections, allergies, foreign objects among other causes. Obviously your Veterinarian may have noticed other symptoms during the physical examination which would indicate congestive heart failure; if you have any doubts, get a second opinion from another Veterinarian in your area. Regards Dr Callum Turner DVM

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Miniature Schnauzer
11 Years
Mild condition
0 found helpful
Mild condition

My dog was recently diagnosed with mitral valve disease during her last check up because a heart murmur was heard. The vet did X-rays and a cardiac ultrasound and determined that at this point no medications are needed because it’s early and she doesn’t have any other clinical symptoms. Is this normal protocol? I was always of the belief that if a medication can be given to slow progression of any illness it is better than waiting around until more symptoms arise.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3320 Recommendations
Whilst it is true that in many cases medications are used to slow the progression of a condition, in many cases with the heart we have medications to help the heart function like increasing contractility of the heart muscle and many medications are contraindicated in cases of asymptomatic patients. Regards Dr Callum Turner DVM

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