Heart (Aortic) Valve Narrowing in Cats

Aortic Stenosis in Cats

The narrowing of the aortic valve, which controls the blood flow from the left ventricle (one of the cat’s four heart chambers) to the aorta ventricular outflow tract, is a congenital (present at birth) defect called aortic stenosis. It is a serious health concern that may lead to various complications.

Symptoms and Types

There are three types of three types of aortic stenosis: valvular (present at the valve), subvalvular (present below the valve), or supravalvular (present above the valve). The defect typically develops over the first few weeks to months of life; however, symptoms may appear at any age, depending on the severity of obstruction. Some of the more common symptoms include:

  • Sudden loss of consciousness (syncope)
  • Congestive heart failure
  • Difficulty breathing (dyspnea)
  • Rapid breathing (tachypnea)
  • Abnormal lung sounds


In most cases, cats are born with the this heart defect. However, some develop the aortic obstruction due to bacterial endocarditis.


You will need to give a thorough history of your cat’s health, including the onset and nature of the symptoms, to the veterinarian. He or she will then perform a complete physical examination, often revealing abnormal heart sounds (murmurs), an indication of irregular heart valve function. However, murmurs are are not always a sign of disease, especially in young animals, as they may occur due to pain, fever, or excitement. Your veterinarian will correlate the findings with other symptoms to determine if the murmur is abnormal. 

The veterinarian may also conduct several laboratory tests, including complete blood count, biochemistry profile, and urinalysis, though the results are usually normal. Chest X-rays, meanwhile, may reveal an enlarged heart, especially on the left side of the organ. And in cats with congestive heart failure, abnormalities may be detected in the lungs.

For a more detailed evaluation of the heart and related structures, the veterinarian may use echocardiography, which may reveal thickening of the left ventricle wall and aortic valve. In some cats, echocardiography may reveal a dilated aorta due to stenosis, resulting in abnormal blood flow.


Fainting; the respiratory and circulatory systems are suspended for a time


The term for a quick heartbeat


a) A cavity in certain animals b) Term refers to a rear chamber in the heart or a cavity in the brain


The act of making an opening narrower.


An in-depth examination of the properties of urine; used to determine the presence or absence of illness


The prediction of a disease’s outcome in advance


Having a hard time breathing; breathing takes great pains


A procedure that is used to evaluate the health and structures of the heart


An inflammation of the lining of the heart


The name of the main artery that starts in the left ventricle of an animal’s four chamber heart.

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