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Dear Most Esteemed and Knowledgeable Kitties:

Three weeks ago I was adopted by a 9-week-old kitten who showed up on my deck crying for help. Tesla is the sweetest, kindest, most lovely little cat I’ve ever encountered. Of course, I took her to the vet the day after she arrived to have a check-up, plus shots, deworming, and flea treatment. Fortunately, she tested negative for Feline HIV and leukemia. However, she did have a level 3 heart murmur, and the vet recommended a heart ultrasound, which she had today. Her diagnosis is “moderate pulmonic stenosis,” which is apparently a very rare congenital defect for cats. While the vet was very kind and answered all the questions I could think of right then, I still feel very concerned for my little cat, and I was wondering what you could tell me about the condition and what it might mean for Tesla’s quality of life. Thank you!

~ Stefanie

Young tabby and white kitten with green eyes

Young kitten, CC-BY-SA by Wikimedia user Maxo

Siouxsie: Wow, little Tesla sure is lucky she adopted you! It’s wonderful that you care so much about her that you’ve already gone ahead and figured out why she has a heart murmur. It’s hard to believe, but a lot of people wouldn’t even do that.

Thomas: Your vet is right: pulmonic stenosis is very rare in cats. Dogs do tend to be born with it more often.

Bella: The good news is that kitties with mild to moderate pulmonic stenosis can live well into their middle years or even their full lifespan with good care and a low-stress life.

Siouxsie: So, let’s start out with a lesson on what pulmonic stenosis is. The word stenosis in medical terminology means “narrowing” or “constriction.” And the word pulmonic means “related to the pulmonary artery.”

An image of a heart with an arrow pointing out pulmonic stenosis

In this picture of a heart with pulmonic stenosis, the yellow arrow points to the pulmonary artery (purple), which is a lot smaller than it should be, so the heart has to work harder to pump blood to the lungs.

Thomas: “But what is the pulmonary artery?” you may ask. It’s the artery that moves blood from the heart to the lungs so it can pick up oxygen and deliver that oxygen to all the cells in the body.

Bella: So, when that pulmonary artery is narrowed, the heart has to work harder to push blood into the lungs.

Siouxsie: And because the heart has to work so hard, sometimes the blood swishes back around, which is what causes the heart murmur your vet heard.

Thomas: Usually, your vet won’t even find out about the stenosis until they detect a moderate to severe heart murmur — Grade III is considered moderate — and suggest further diagnostic tests to determine what’s causing the murmur.

Bella: Any time a cat has a blood flow problem that makes the heart work harder, a few things can happen. First, the cat could be easily winded when exercised: you might find that after only a little bit of play, little Tesla might be panting because she’s not getting enough oxygen to her body.

Siouxsie: She might even faint if she’s severely stressed, overheated, or over-exercised.

Thomas: One thing you should watch for is panting at rest. This could be an indication that fluid is backing up into the rib cage and collapsing Tesla’s lungs. If you see this, she should go to the vet immediately, even if it means a trip to the emergency clinic.

Bella: If Tesla develops this condition, the vet will probably drain the fluid from around her lungs and prescribe diuretics — medicines that will help the body get rid of the extra fluid buildup by making her pee more.

Siouxsie: If the symptoms continue or appear to be getting worse, your vet may recommend a procedure called balloon valvuloplasty, where a tiny balloon is fed through the blood vessels and inflated to stretch that valve and allow more blood to flow to the lungs.

Thomas: We’d think a consultation with a veterinary cardiologist could give you more information about the pulmonic stenosis, available treatment options, and what it means for your cat’s long-term quality of life.

Bella: We’re not vets, of course, so if your vet says something different than we said here, please go with your veterinarian’s word! Good luck to you and Tesla, and thank you for loving this little girl enough to rescue her and take care of her health needs.