Subvalvular aortic stenosis
Overview
SAS or subvalvular aortic stenosis. Sub aortic stenosis is the second most common canine heart malformation and is defined as an "obstruction of the left ventricular outflow tract that ranges in severity from an incomplete fibrous ridge to a fibromuscular tunnel", and lies just under the aortic valve.
Symptoms
an animal might have signs of Subaortic stenosis, and yet offspring with signs of SAS may not be seen for a couple of generations. Any animal that has Subaortic stenosis should not be bred, because they can definitely pass the defect on to future offspring. There is some controversy as to whether the parents of an animal with SAS should be bred again.
Causes
There is also very good evidence that it is also heritable, passed on from generation to generation genetically. This genetic trait is what is called polygenic, so that the inheritance is complex.
Diagnosis
The condition is usually detected during puppy visits to the veterinarian by hearing a heart murmur during physical examination. A heart murmur is the abnormal sound of blood rushing through one of the heart valves. Instead of just the heart beat, a whistle of blood flow through a narrowed opening is heard. The puppy will most likely appear normal in all other respects. There is a possibility that the murmur may come and go, or it may develop slowly; therefore, it is important to have a veterinarian check a puppy's heart often during the first few months of age. This is a very frustrating condition to be identified in your pet because the future is bleak and the chance for long term survival is low. Puppies and dogs diagnosed with Subaortic stenosis can suffer from heart failure and sudden death. If your dog with SAS develops heart failure, medications can be prescribed to alleviate the clinical signs it is experiencing.