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Aortic Stenosis

General Information

Aortic stenosis is a congenital (present at birth) heart defect that is most common in German Shepherds, Newfoundlands and Boxers. In this condition, narrowing of the aorta (the large artery that distributes blood from the heart) forces the heart to beat faster and harder to pump blood to the rest of the body. This can lead to heart failure.

While some young puppies with aortic stenosis appear completely healthy, others tire quickly, are stunted, and have fainting spells. Sudden death at 6-18 months of age is common.

Dogs with mild stenosis (narrowing) may live for many years without developing heart failure, but once signs of heart failure develop, the chances for a normal life are poor.

Diagnosis of aortic stenosis frequently involves radiographs (x-rays), electrocardiograms, angiography or echocardiography.

Important Points in Treatment

1. Many cases of aortic stenosis are correctable with open-heart surgery; however, the procedure requires a heart-lung bypass, and is relatively risky and quite expensive. Therefore, the procedure is not often performed.

2. Medical treatment often prolongs the life of dogs with early signs of heart failure due to aortic stenosis.

3. All the medication must be given as directed. Please call the doctor if you cannot perform any recommended treatments.

 

Notify the Doctor if Any of the Following Occur:

* Your pet develops a cough or difficult breathing.

* Your pet seems fatigued or tires easily.

* Your pet has diarrhea or vomits.

* Your pet is reluctant to eat.

Understanding your Pet's Diagnosis

Aortic Stenosis
The heart is the organ (or system) which frequently fails in the dog and surprisingly, it happens to dogs of all ages. In the young, this is typically the result of congenital abnormalities in the formation of the heart or blood vessels, which surround it. In older animals, it is usually a case in which one side or chamber is weakened or over worked due to altered circulatory patterns.

The heart is actually nothing more than a mechanical pump. It accepts blood on one side and forces it through the lungs, then its other half pumps the liquid on through the entire body. The heart does not change or alter the blood in any way. It has no glandular tissue and therefore secretes nothing into the blood nor does it extract anything. It is probably the simplest and most easily understood organ in the entire body.

As a quick review, blood returns from the body and enters the right upper chamber of the heart, called the right atria. At this point, the blood is low in oxygen but high in carbon dioxide. It is then pumped from the atria through the right atrioventricular valve into the right ventricle. From this larger chamber, it is then forced on into the lung field through he pulmonary artery. This is the only artery in the body that carries non-oxygenated blood. Carbon dioxide is a byproduct of body metabolism and is attached to the red blood cells. In the lungs, carbon dioxide is replaced with oxygen. The reoxygenated blood then moves through the pulmonary vein back into the heart and enters the left atrium. This chamber pumps the blood through the mitral valve into the left ventricle, which is the largest, most heavily muscled chamber of the heart. While other chambers only move the blood a short distance, the left ventricle has the responsibility of forcing blood throughout the entire body. This completes the system, which allows blood to circulate throughout the body and then return to the heart.

In young dogs, a congenital condition referred to as aortic stenosis affects the left side of the heart. When the left ventricle pumps blood to the body, it goes first through the aorta. This huge artery then branches into smaller ones that supply different areas. With aortic stenosis, the opening between the left ventricle and aorta is smaller than normal causing the left ventricle to work much harder to force the required amount of blood through the restricted area into the aorta and on to the rest of the body. Animals with this disorder are weak, lethargic, prone to fainting and may have poor growth rates. All of these signs are due to inadequate profusion of the tissues with nutrient and oxygen-rich blood. These animals typically have much shortened life spans and death finally results from left-sided heart failure. Even though the left ventricle is extra strong, it cannot maintain this workload over time. Only surgical opening of the stenotic area of the aorta provides a true cure.


The information on this page was obtained from the site www.peteducation.com