Tricuspid Valve Dysplasia in Dogs

The tricuspid valve is supposed to be a one-way valve that shuts tightly, so not to allow backflow.  If the valve is malformed it allows blood to flow backwards.  This disorder causes the heart to have to work much harder.  As the dysplasia continues the heart becomes enlarged. If left untreated, tricuspid valve dysplasia can be fatal.

Tricuspid valve dysplasia can be seen in any breed but it is more commonly diagnosed in large breeds such as German Shepherds, Labrador Retrievers, Irish Setters, Old English Sheepdogs, and Great Danes.  Males dogs are more predisposed to TVD.

Tricuspid valve dysplasia is a very uncommon heart condition in dogs. The tricuspid valve regulates the flow of blood from the right atrium to the right ventricle.  The congenital malformation of the tricuspid valve can cause a backflow of blood (regurgitation) back into the right atrium.

Symptoms will depend on the severity of tricuspid valve dysplasia.  Mild cases of tricuspid valve dysplasia may not show any visual signs. 

• Distended stomach due to fluid accumulation (ascites)
• Exercise intolerance
• Dyspnea due to lack of oxygen in the bloodstream
• Heart murmur
• Rapid heartbeat
• Weakness

Tricuspid valve dysplasia (TVD) is an inherited congenital cardiac condition that causes abnormalities to the tricuspid valve.  This means that tricuspid valve dysplasia occurred during fetal development.   The dog is born with the heart condition.  Dogs diagnosed with tricuspid valve dysplasia should not be bred.

The initial veterinary examination may include taking the patient’s weight, temperature, blood pressure and pulse.  He may palpate the patient’s abdomen to check for fluid build up and to evaluate the muscle tone.  The veterinarian will also want to listen to your dog’s heart and lungs.  If the veterinarian hears a heart murmur (irregular sound in the heart) he may suggest a few diagnostic tests, such as an electrocardiogram, chest and abdominal x-rays, and an endocardiogram. These tests can help determine the cause of the irregular sound and the severity of the condition.  A heart murmur is usually an indication of a problem with the blood flow within the heart.

The EKG can detect abnormal heart rhythm due to the heart being enlarged.  Chest x-rays can visualize the shape of the heart and can determine if the lungs have fluid.  The abdominal x-rays can confirm ascites (fluid accumulation). The endocardiogram uses sound waves to check on the heart’s contractions and can determine how much cardio blood is being pumped.

If the patient has a large quantity of fluid in his abdomen the veterinarian may remove the fluid performing an abdominocentesis. Patients with tricuspid valve dysplasia will need to be on low salt diets.  Overweight dogs will have their diets charged, to encourage weight loss.  Extreme exertion should be avoided; limited moderate exercise will be permitted. Supplements and vitamins may be suggested such as Vitamin E, coenzyme CoQ10, and Omega 3. 

The veterinarian may prescribe digoxin, furosemide and an angiotensin enzyme inhibitor. Diuretics may help with fluid retention. Vasodilators drugs can help the heart have better blood flow. The treatment plan may improve the patient’s quality of life.  Patients that are not responding to the treatment plan may be referred to a cardiac veterinarian specialist.  Surgery may be recommended to replace the valve, if the dog is strong enough to undergo the procedure. Replacement of the tricuspid valve is a high risk surgery.

The treatment plan for tricuspid valve dysplasia will be a lifetime commitment.  Follow-up visits will be needed to monitor the patient’s progress. The veterinarian may want an electrocardiogram, x-rays and an endocardiogram to be repeated every few months. The removal of the abdominal fluids will need to be done periodically.  Medication side effects must be monitored.  Treatment of tricuspid valve dysplasia does not cure the condition; it makes the dog more comfortable. Dogs that are not responding to the treatment plan and for whom surgery is not an option may need to be humanely euthanized.  Patients that underwent surgery will have post-operative instruction provided once the dog is released from the hospital.