Dear Most Esteemed and Knowledgeable Kitties:

My 9-month-old female cat has a heart murmur and serious heart problems diagnosed by ultrasound. The vet says she has a 1 in 3 chance of surviving sterilization. He has recommended the pill. Her life expectancy is reduced because of the heart condition, so he says she will probably die before the side effects of the pill kick in. What is your advice, please? I worry about my lovely little cat, who is so energetic it’s difficult to believe she has a heart condition. She is, however, showing signs of going into heat, so I need to decide as quickly as possible what is best for her.

~Janette

Siouxsie: We’re so sorry to hear your sweet little kitty has such serious heart problems. We also thank you for doing everything to make sure you have an accurate diagnosis and take the best care of her you possibly can.

Thomas: As your vet probably told you when he discovered your kitty’s heart murmur, heart murmurs are graded from 1 (barely detectable) to 6 (can be heard without a stethoscope and sometimes associated with “flurrying” movements of the chest). Doctor Sarah once heard a heart murmur in my chest, but it was about a 1 or 2 on the scale and she couldn’t hear it at all at my next exam.

Dahlia: Cats sometimes develop heart murmurs when they’re really scared and stressed and their hearts beat really fast–which is what happens when Thomas goes to the vet. He hates going to the vet, poor guy. I mean, none of us like the ride in the car part, but Thomas is terrified of the office part, too.

Siouxsie: But more severe murmurs, such as the one your cat apparently has, call for more complex diagnostic tests such as an ultrasound in order to find out what’s going on.

Thomas: Murmurs can indicate abnormal heart valves, heart muscle diseases such as cardiomyopathy, a birth defect that causes an abnormal opening between sides of the heart, or by non-cardiac causes such as anemia, heartworm disease, or abnormal thyroid function. Any of the heart diseases and malformations can cause major risks during surgery.

Dahlia: Presumably your cat has one or more of these conditions if your vet has told you her chances of surviving surgery are 1 in 3.

Siouxsie: If a human had one of these heart problems, they’d probably have open heart surgery to fix the problem–or perhaps even a heart transplant if needed. But they don’t make heart-lung machines for cats (required for open heart surgery) and to the best of our knowledge, a heart transplant has never been attempted on a cat.

Thomas: Given this information and your knowledge that your kitty’s heart problems are going to lower her life expectancy, the thing you need to do is figure out what’s going to give your cat the best quality of life while she’s with you.

Dahlia: Being in heat is very stressful for cats, especially if they don’t get a chance to mate. Because of her heart diseases, you want to help your cat avoid stress, so it’s important to keep your cat out of heat.

Siouxsie: And if you think being in heat is hard on a cat, just imagine the effects of pregnancy! Pregnancy puts a lot of strain on the heart, and if your kitty’s heart is that bad, she may not survive a pregnancy either.

Thomas: With all that in mind, we think it really would be the best choice to put your cat on birth control in order to prevent her from going into heat.

Dahlia: We’ve heard of two types of birth control medications used in cats, megestrol acetate (the most common, sold under the brand name Ovaban), and Depo-Provera (that’s right, the human “depo shot”). Both of these are progestin-only formulas; that is, they are similar to the natural hormone progesterone. Progesterone stays at high levels during pregnancy, so progestin-based birth control fools the body into thinking it’s pregnant–which is how it controls heat cycles in cats and keeps humans from ovulating.

Siouxsie: We imagine Ovaban is much easier to obtain–and probably less expensive than–Depo-Provera, which is why your vet recommended the pill rather than the shot.

Thomas: Long-term use of Ovaban can have serious side effects including increased risk for uterine infections, harm to the adrenal glands, and transient episodes of diabetes. This is why vets don’t recommend medical birth control for healthy cats. If your cat doesn’t already have a severe illness that greatly increases the risk of surgery, vets will prefer to spay or neuter.

Dahlia: But as we said above, you need to consider your cat’s quality of life above all. The stress of heat–which will only become more frequent and unbearable the longer she remains unsatisfied–could have a serious impact on her health. Your sanity will probably suffer, too!

Siouxsie: We think using birth control medication for your cat will bring you both a higher quality of life, and you’ll both be able to enjoy your time together as much as possible–no matter how short or long that time may be.

Thomas: Good luck, Janette. Please let us know how things turn out. We like hearing back from our readers about their experiences because it helps us to help our other readers.

Dahlia: And for those of you who want to know more about heart murmurs, we recommend this article at petplace.com as a good starting point.