VCA Animal Hospitals

What are heart murmurs in cats?

Published: Jun 29, 2012

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Heart murmurs in cats are a somewhat common problem, and can vary drastically in severity and scope. A heart murmur refers to an abnormal heart sound that the veterinarian picks up while listening to the cat's heartbeat with a stethoscope. Since a variety of different issues can cause a heart murmur, the prognosis for the feline will vary.

Since heart murmurs vary so widely, vets grade them on a scale of I-VI, with a Grade I heart murmur being the least intense. These heart murmurs will be very quiet, whereas a Grade VI heart murmur is very loud and may even be felt or heard without a stethoscope.

Some murmurs are benign and have no impact on a cat’s health because they are not caused by disease. These murmurs are called "innocent" or "physiologic" heart murmurs and are typically found in young growing kittens, although they may also be detected intermittently in adult cats. Most innocent murmurs are of low intensity and are usually Grade I or II. Vets will not prescribe any specific treatment for these heart murmurs because they have no effect on the cat's health, and will typically disappear on their own over time.

Heart disease in cats may also cause murmurs. Structural heart problems may be congenital—meaning a cat is born with a defect, or may be acquired—meaning it is a disease which develops later in life. The magnitude of the heart murmur will vary in these conditions but often will be grade III or higher in intensity.

The two most common congenital defects are ventricular septal defect (VSD) or atrial septal defect (ASD), both of which will cause heart murmurs in young cats. Cats may also be born with defective heart valves which can also cause murmurs.  The most common acquired disease seen in older cats is called hypertrophic cardiomyopathy which is a thickening of the heart muscle which causes a disturbance in the flow of blood, which results in a heart murmur. Murmurs can also be caused by a variety of fevers and infections, though these are less common.

Owners should realize the heart murmur itself is not what's harmful. Instead, the murmur is possibly indicative of an underlying issue in their cat. Your veterinarian will likely recommend chest radiographs (x-rays) or possibly an ultrasound of your cat’s heart in order to identify the underlying cause of the heart murmur. Then, if necessary, medication or other therapy will be prescribed to address the underlying heart disease, if present.


General Practice

We have over 540 animal hospitals in 41 states that are staffed by more than 2,000 fully qualified, dedicated and compassionate veterinarians, with more than 200 being board-certified specialists. The nationwide VCA family of general practice hospitals give your pet the very best in medical care, providing a full range of general medical and surgical services as well as specialized treatments*: Wellness, Spay/neuter, Advanced diagnostic services (MRI/CT Scan), Internal medicine, Oncology, Ophthalmology, Dermatology, Cardiology, Neurology, Boarding, Grooming

*services may vary by location.

Our family of pet hospitals stands out by delivering the greatest resources in order provide the highest quality care available for your pets. By maintaining the highest standards of pet health care available anywhere, we emphasize prevention as well as healing. We provide continuing education programs to our doctors and staff and promote the open exchange of professional knowledge and expertise. And finally, we have established a consistent program of procedures and techniques, proven to be the most effective in keeping pets healthy.

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Specialty Care

Sometimes sick or injured pets need the care of a veterinary medical specialist. When that happens, VCA specialty hospitals work closely with the general practitioner veterinarians who refer cases to us in order to provide seamless veterinary care to your pet. When your pet is facing any kind of serious illness or injury, our specialty referral hospitals will provide the compassionate and expert care your beloved pet needs.

Our goal is to make sure that when you and your pet are in need that you have access to board certified specialists who are up to date on the very latest developments in their field. In our state of the art hospitals, our specialists also have access to the most sophisticated diagnostic and treatment tools and techniques from ultrasonography and endoscopy to CAT scans and even MRI.

We have twenty-eight specialty hospitals across the US so there may be one near you. Our specialized services include: cardiology, critical care, dentistry, dermatology, internal medicine, neurology, oncology, ophthalmology, radiology and surgery.

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Emergency Care

In case of emergency, please call us immediately. If it is after hours, check with a local animal hospital emergency clinic.