Companion Animals

Canine Subvalvular Aortic Stenosis: Welfare and Breeding

Subvalvular aortic stenosis (SAS) is a heritable heart defect common in certain large breeds causing exercise intolerance, syncope and sudden death with significant welfare implications.

Key Facts

SAS is the second most common congenital heart defect in dogs, most prevalent in Newfoundlands, Golden Retrievers and Boxers
It causes a fixed obstruction to left ventricular outflow, increasing cardiac workload
Mild cases may live normal lives while severe SAS carries a poor prognosis and risk of sudden death
Breeding programmes should screen for SAS using auscultation and echocardiography before mating

Welfare Considerations

SAS causes welfare impacts ranging from exercise intolerance and syncope in moderate cases to sudden cardiac death in severe cases. Affected dogs may develop secondary arrhythmias and heart failure. Welfare priorities include screening breeding animals, providing owners with realistic prognosis information, avoiding strenuous exercise in affected dogs, and treating arrhythmias with antiarrhythmic medication.

What You Can Do

Screen all Newfoundlands, Golden Retrievers and Boxers for cardiac abnormalities before breeding
Have a cardiologist evaluate any dog with a cardiac murmur before breeding
Restrict exercise in dogs with confirmed SAS based on veterinary advice
Choose puppies from health-screened parents from reputable breeders