Subaortic stenosis (SAS) is an insidious hereditary condition that may show no outward sign in an apparently healthy dog. Suddenly, the dog may simply drop over, dead. A narrowing of the outflow tract of the left ventricle is what causes SAS. In this case, the narrowing occurs below the aortic valve. The heart must work harder to push more blood through the narrow opening, causing more problems.
Signs of heart problems vary. Your rottie may tire easier or have trouble breathing, running, or being active. In severe cases, his skin may turn pale or blue, or he may have fluid buildup in his legs. He may faint. Any of these symptoms are serious, and you should have your rottweiler examined by a vet.
SAS can be difficult to diagnose. The heart murmur, a common symptom of SAS, may be difficult to detect. The dog may also have arrhythmias. A veterinary cardiologist can diagnose SAS through either Doppler echocardiography or cardiac catheterization. The prognosis for a long, healthy life is poor.
Dogs with SAS should not be bred since this is a genetic disease that may be passed to future generations. OFA has a cardiac registry, but there are very few dogs registered with the registry (only 1,192 dogs as of December). Only purchase a puppy from a reputable breeder who has cleared dogs registered with the OFA.