What is subaortic stenosis (SAS)?

SAS is a birth defect causing a narrowing of the passage of blood from the left ventricle (pumping chamber) into the blood vessel that supplies the body (aorta). This narrowing usually develops in the first year of life. SAS is most commonly diagnosed in Newfoundlands, Golden Retrievers, Boxers, and Rottweilers, but can affect any breed.

What are the symptoms of SAS?

SAS is most often detected in asymptomatic, young dogs when a heart murmur is detected upon listening to the chest with a stethoscope. An ultrasound of the heart (echocardiogram) performed by a cardiologist is required for diagnosis.

When the disease is mild to moderate, dogs may be asymptomatic for many years and live normal life-spans. Dogs with severe SAS are at high risk for fainting and sudden death during the first three years of life, and for development of fluid build-up in the lungs (congestive heart failure) for the following years. All dogs with SAS may be at increased risk for development of infection on their heart valves.

What are the treatment options and prognosis?

If SAS is mild, treatment is typically not required and dogs may live normal life-spans. If the disease is moderate or severe, medications may be prescribed to reduce the heart rate and prevent abnormal heart rhythms. Limiting physical activity may be recommended to decrease the risk for fainting. Surgical options may be discussed with your cardiologist, but are not commonly performed. If the disease progresses to CHF, most animals can live with good quality of life on medications for 6-12 months. All dogs with SAS should receive prophylactic antibiotics during any elective surgical or dental procedure.