Yes, it can be. It is a tricky condition... Some Boxers have a mild case which does not affect life span at all... However, with others, it can be severe and fatal.
Abnormal heart rhythms in a dog can lead to sudden death.
Breeding / Hereditary Issues
A dog (either sire or dam) with a mild case can pass the disease to a litter in which a puppy or puppies contract a very serious case. For this reason, a dog with this should not be bred even if he/she has a mild case that is not affecting his/her quality of life.
Any dog that is being considered for breeding should be tested for this - along with Doppler studies (a particular type of ultrasound machine that uses sound waves to measure the flow of blood through a blood vessel) - by a board-certified canine cardiologist prior to any pairing.
Once a Boxer is cleared of this and is at least 1 year old, he/she is considered clear and can entered into a breeding program.
How is this Diagnosed?
Once a heart murmur is detected, your Boxer dog should be referred to a canine heart specialist. One of the most important aspects will be to determine the severity of the murmur.
Testing will be done to determine the exact location of the most intense area of the murmur and then the murmur will be graded on a scale of 0/6 to 6/6 (more ahead)
An X-ray of the dog's chest is usually performed. This is helpful to see the size and shape of the heart. Any abnormal enlargement of the heart's chambers can usually be spotted, which would indicate a more severe case.
An EKG is important as it will determine the severity of the heart's valve narrowing and it will measure electrical impulses to the Boxer's heart.
With Aortic Stenosis, the left ventricle wall of the heart thickens. This test will measure the extent of the thickness and well as the internal dimensions of the heart.
Doppler Test -
A Doppler test is a specialized ultrasound test that measures the flow of blood through a blood vessel. Of most concern, will be the left ventricle. The flow rate can tell you a lot. Flow is measured by meters per second.
If a dog has a flow that is LESS than 4 meters per second, he will usually live to full life expectancy
and not have any major problems.
If a Boxer has a flow that is MORE than 5 meters per second, this is an indication that the dog will be affected by this disease; though all tests will be combined together to give the murmur a 'grade'.
This is the grading system:
This is considered to be very mild and will not affect quality of life or life span
- This is also in the mild category. 95% of Boxer dogs that are in the class will not develop symptoms that impede his/her health
- A murmur of this scale is considered to be moderate. Most Boxer puppies
and dogs will not suffer from any symptoms; however 10 to 15% will. Dogs given a grade of either 3/6 or 4/6 should be watched closely and monitored often to check for possible problems and to see if the murmur worsens as the dog ages.
At this grading, the murmur is considered to be severe. Unfortunately, the majority of Boxer dogs that are graded with a 5/6 or 6/6 are likely to develop symptoms and may have shorter life spans. Medication will most certainly be given and the dog must be monitored on a regular basis.