A life-threatening heart condition in Dogs known as Tetralogy of Fallot

A life-threatening heart condition in Dogs known as Tetralogy of Fallot

Health & Safety

Some dog breeds are more predisposed to inheriting a congenital heart defect that negatively impacts the organ’s function which is known as tetralogy of Fallot. The condition sees four abnormalities in a dog’s heart which often proves fatal if not diagnosed early enough and even then, the prognosis tends to be poor with many dogs succumbing to the condition before they reach two years of age.

A rare but fatal birth defect

Fortunately, the condition is a rare birth defect that appears to affect certain breeds more than others. Typically dogs with the condition are diagnosed when they are between 2 and 8 months old and if they are not given the correct treatment, most will die before they are 1 year old.

Breeds most at risk

As previously mentioned, certain breeds appear to be more predisposed to inheriting the congenital heart birth defect and this includes the following:

  • English Bulldog
  • Keeshond

The symptoms associated with the disorder

Dogs suffering from the heart defect show the following symptoms:

  • Weakness
  • Fainting
  • Seizures
  • Intolerance to exercise
  • A Shortness of breath - dyspnoea
  • Cyanosis

The causes

The disorder, as previously touched upon is a congenital heart defect that is thought to be congenital. As such, a dog would inherit the problem from their parents should they be suffering from the condition too.

Diagnosing the problem

A vet would want to have a dog’s full medical history and be told of their lineage before giving them a thorough physical examination to see if they can establish whether they have a heart murmur. The tests the vet would recommend carrying out would include the following:

  • A full blood count
  • X-rays of a dog’s heart
  • An ultrasonic study of the dog’s heart which is referred to as being an echocardiogram
  • An electrocardiogram (ECG)
  • A pulse oximetry
  • An angiocardiography

Treatment options

A vet would recommend restricting the amount of exercise a dog suffering from the condition is given with an end goal being to reduce the amount of strain that their hearts are put under. Other treatments a vet might recommend and set in place include the following:

  • Periodic phlebotomy to restore red blood cell balance
  • Hydroxyurea as an alternative to phlebotomy although the side effects of the treatment must be factored in
  • Beta blockers to help maintain levels of blood oxygen


Since surgery is not really an option, palliative care of a dog suffering from tetralogy of Fallot is all-important and as such careful management of their condition is essential to improve the prognosis. Dogs with the condition must be taken for regular check-ups with the vet to ensure the correct dosage of medication is being administered to them. This means regular health checks and treatments throughout a dog’s life.

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