In one sentence, describe what the following article is about:

Your German Shepherd may have a hard time pumping blood throughout his body if his aorta is deformed. The aorta is the main artery leaving the heart. If the valve into the aorta is narrowed, as in AS, a backpressure is created in the heart making your dog work harder to circulate blood. Medication is the most common treatment for AS, which treats the irregular heart rhythm and may include antibiotics to prevent infection. Surgery is not recommended. Your German Shepherd may have a heart deformity that's causing a heart murmur or another health condition (like problems eating or with blood circulation). These deformities may include:  Patent ductus arteriosus (PDA): This is a temporary blood vessel in a fetal puppy that should close shortly after he's born. If it stays open, blood may bypass your dog's lungs. Vascular ring anomaly (also known as persistent right aortic arch): This is another blood vessel that should close before your dog is born. If it stays open after birth, the vessel traps your dog's esophagus which makes it hard for him to swallow food down into his stomach.  Mitral or tricuspid valve disease: These valves separate the heart's atria from the ventricles. If they don't fit perfectly together, then blood can leak in the wrong direction, causing a heart murmur. If your dog has abnormalities in the heart muscle itself, he may have dilated or hypertrophic cardiomyopathy. With Dilated cardiomyopathy (DCM), the heart muscle tires and becomes baggy. With hypertrophic cardiomyopathy, the heart muscle thickens, causing the chambers to get smaller and hold less blood. Treatment usually focuses on improving your dog's diet and exercise habits. Most vets don't recommend surgery unless your German Shepherd develops congestive heart failure. Older German Shepherds are prone to a vascular tumor (hemangiosarcoma) that attacks the vessels lining the heart. This tumor is the most common type in dogs and usually isn't noticed until it gets big enough to cause complications. Your dog may have abdominal swelling, irregular heartbeat, and anemia. Treatment for hemangiosarcoma is difficult. Veterinarians usually recommend chemotherapy and possibly draining the site of the tumor. Because the tumor is on the heart, treatment may only be able to add a few months to your dog's life.

Summary:
Consider if your German Shepherd has aortic stenosis (AS). Think about whether or not your dog has heart defects. Think about if your dog has cardiomyopathy. Consider if your dog has a tumor.