Cats and Heart Murmurs

When a cat or a kitten’s normal blood flow to the heart is interrupted, the kitten may be experiencing a heart murmur. The occurrences of heart murmurs can be caused by genetic problems, severe anemia, debilitating bacterial infections that  is commonly caused by gum disease or an abscessed tooth. A heart murmur affects the heart valves, blood will begin to leak out of the valves as it is trying to pump blood into the heart. This leakage stops the ability of the heart to pump oxygen-enriched blood into the heart and other vital organs. This stoppage results in a heart murmur.  Your vet will be able to determine if your kitten/cat has a heart murmur by listening to the kitten’s heart. He will be able to hear the blood leaving the valve.

Kittens can outgrow heart murmurs. Depending on the severity of the murmur, your vet might postpone spaying and neutering until the kitten is older. Most cats who have heart murmurs can live long, healthy lives. Only in a small percentage of heart murmurs can this lead to severe heart problems. Your vet will schedule follow up exams every 3-6 months to determine if the kitten is clear of a heart murmur.

Murmurs are classified as Innocent, Functional or Pathological. Your vet when he is listening to your cat’s heart he is gauging the frequency, how loud or intense the noise is, where the noise is located, how continuous or infrequent it is. The intensity grade ranges from I-VI VI meaning that the noise is loud enough; the vet can hear the murmur with his stethoscope placed near but not on the thoracic wall. The problem lies in the senior cat developing abnormalities to the heart valve over time because of the interruption of the blood flow to the valve. 

Symptoms:

• Listlessness or lethargy
• Lack of appetite
• Wet cough (meaning there is liquid in the lungs/heart)
• Abnormal shallow breathing
• Anemia (most often after heavy flea infestation)

The only way to find out exactly how much damage has been done to the heart valve is to run an extensive ultrasound on the cat/kitten. This measure is not usually advised unless the vet believes the murmur is heading toward Feline Hypertrophic Cardiomyopathy. Unless your vet specializes as a cardiologist, he should refer you to veterinary cardiologist for this test. Your cat will be awake during the ultrasound. X-rays are inconclusive to determine the extent of the damage. Your vet needs a detailed picture of what is going on around the heart before advising you on how to proceed. Cats can live for years with heart murmurs without developing any adverse health issues. The prognosis depends on what grade the murmur is rated along with the lifestyle and diet of the cat in question.