Pet Care Blog

Heart Murmur in Cats: Everything You Need To Know

Dr. Ricky Walther
Cat heart murmur

A heart murmur is an abnormal heart sound that is usually detected during a routine exam when the veterinarian listens to your pet's heart with a stethoscope. But should it be a cause for concern? Not necessarily. Many healthy felines with a heart murmur never develop any heart issues and go on to lead long and healthy lives.

Read on to find out what causes heart murmur, how serious it is, and what it might mean for your cat.

Table of Contents

Pro Tip: To effectively manage health issues like heart murmur, getting health insurance is highly recommended. Depending on the pet insurance plan, diagnostics, hospitalization, specialist appointments, and surgery may be covered.

What is a heart murmur?

A heart murmur is an abnormal sound that a vet can hear when listening to a cat’s chest, caused by a turbulent blood flow.

Based on the loudness and intensity, vets rank heart murmurs in grades from one to six, with one being softest and six being the most audible. Softer murmurs might only be detectable in one place, whereas the loudest ones can be heard in multiple places on the cat’s body.

A heart murmur doesn’t have to be a reason to panic, but it might indicate a heart condition. Depending on your pet’s condition, the vet might decide to perform additional diagnostic testing in order to determine the cause of the heart murmur.

Heart murmur in cats symptoms

The clinical signs of a heart murmur can vary depending on several factors. In fact, most heart murmurs are asymptomatic until they are advanced. In many cases, symptoms can be very subtle and non-specific, sometimes consisting of weight loss, decreased appetite, weakness, and lethargy.

If the heart disease has progressed, the most common symptoms are associated with fluid build-up in the lungs and might include rapid or difficult breathing, coughing, respiratory distress, and collapse. All these are signs of heart failure.

If you notice these symptoms or anything unusual with your pet, be sure to call your vet as soon as possible.

Vet listening to cat's heart murmur

What causes a heart murmur?

There’s a number of conditions that can cause heart murmurs in cats. Some of them are benign and might not affect your pet's health, while others are serious and potentially life-threatening.

Heart murmurs can be related to structural problems within the heart. Your kitty might have been born with a heart defect (congenital heart disease), such as ventricular septal defect or pulmonic stenosis.

Some cats acquire heart disease later in life. Diseases of the heart muscle or cardiomyopathies can cause abnormal heart function, including a heart murmur.

Heart murmurs in cats can also be associated with conditions outside the heart (extracardiac conditions), such as infection, fever, increased blood pressure, anemia, or hyperthyroidism.

Murmur can also occur in geriatric, emaciated, pregnant, or overweight felines.

What is an innocent murmur?

An innocent or physiologic heart murmur is a benign murmur that is usually asymptomatic and low in intensity. They’re quite common in kittens but adult cats can also have temporary heart murmurs as a result of stress, which causes increased heart rate. This type of murmur disappears when the heart rate is normalized and has no impact on the animal's health.

In general, innocent heart murmurs have a low intensity (usually Grade I or II) and don’t cause any symptoms.

Heart murmur in kittens

One type of innocent or physiologic heart murmur is often found in small kittens, especially in kittens who are growing rapidly. The heart murmur usually first appears at six to eight weeks of age, and usually disappears around four or five months of age. This type of heart murmur is benign.

Man holding kitten with heart murmur

Diagnosis of heart murmurs in cats

If the murmur was noticed for the first time and your kitty showed no symptoms, your vet might simply recommend that you return for re-evaluation. Many cats are nervous and stressed during the physical examination so the vet will want to see your pet when they’re calmer as the murmur could have been physiologic.

If your cat shows symptoms or the heart murmur seems to be resulting from an underlying issue, the veterinarian will likely order additional diagnostic tests. These may include a complete blood count to detect infections or anemia, blood pressure tests to check for hypertension, chest X-rays to look at lungs and heart, and an electrocardiogram to check the heart rate and rhythm.

The veterinarian might also perform an echocardiogram, i.e. an ultrasound to exam the heart. This might be accompanied by a Doppler examination to help determine the exact location of the cause of the murmur.

Treatment for a heart murmur in cats

Whether the cat's heart murmur needs treatment will depend on several factors, including the cause, the severity of the murmur, how advanced it is, and what symptoms your cat is showing.

Treatment options also vary depending on the cause of the heart murmur. If it is benign, no treatment is required, and your veterinarian will simply monitor your pet's health more frequently. However, if the cat's murmur is a result of an underlying condition, your vet might prescribe medication and/or a special diet. The most commonly used medications are beta-blockers, calcium channel blockers, diuretics, and anti-clotting medications. If the murmur is caused by a congenital disease, the veterinarian might recommend surgery.

Pro Tip: Heart murmur should be monitored, especially in overweight, senior, and pregnant cats. Pet insurance is valuable because it allows you to face issues like this head-on by providing your cat with the best care while minimizing the hit to your bank account.

Heart murmur in cats life expectancy

The prognosis depends on the cause of the heart murmur. If the murmur is innocent, no treatment is needed and the prognosis is usually very good to excellent.

If the murmur is caused by a functional problem that is treatable or by an extracardiac disease, it might resolve over time. If the murmur is caused by cardiac disease, the long-term prognosis will depend on the specific type of cardiac disease.

Depending on the diagnosis, lifestyle changes might be required in order to manage your pet's condition, such as exercise and changes in the diet. Make sure to give any prescribed medications and take your cat for follow-up checkups according to your vet’s instructions.

Key Takeaways

  • A heart murmur is an abnormal sound that a vet hears when listening to the cat’s heart through a stethoscope. Not all murmurs should be a cause for concern, but they can indicate underlying heart disease.
  • Innocent murmurs are quite common in kittens. They are typically harmless and usually disappear by 4-5 months of age.
  • Signs of heart disease in cats include rapid breathing, weakness, lethargy, and collapse.
  • To diagnose the cause of a heart murmur, your vet might recommend tests such as blood tests, echocardiograms, and chest x-rays.
  • If you have any questions or concerns about your cat’s health, be sure to get in touch with your vet.

Do you want to find the best pet insurance?

Let's analyze your pet's breed, age, and location to find the right coverage and the best savings. Ready?

Analyze My Pet

About Pawlicy Advisor

The pet insurance marketplace endorsed by veterinarians, at Pawlicy Advisor we make buying the best pet insurance easier. By comparing personalized coverage and pricing differences we can save you a ton of money, up to 83% in some instances!

Pawlicy Advisor helping a pet parent and their dog find a great deal on insurance

Instantly Compare Pet Insurance Plans

Get Quotes


How Pet Insurance Works

How To Compare Plans

Determine If Pet Insurance Is Worth It

Determine If Wellness Plans Are Worth It

Vet Visit Costs

New Puppy Checklist

Comparison Charts

ASPCA vs. Pets Best

Pets Best vs. Embrace

Embrace vs. Pumpkin

Pumpkin vs. MetLife

More Comparison Charts

Find Your State

New Jersey





New York



More States

Dog Insurance

German Shepherd




English Bulldog

French Bulldog

Great Dane





More Breeds

Ricky Walther, DVM

Dr. Ricky Walther

Ricky Walther, DVM, is a small animal general practitioner in the greater Sacramento, California area. Realizing the positive financial and medical impact that pet insurance can provide for pet parents and the profession, he lends support and advice to companies like Pawlicy Advisor "The Pet Insurance Marketplace") that simplify the process of connecting with veterinary financing resources.

More you might like

Boxer dog running
6 minute read

Boxer Breed Guide

White and black French Bulldog
6 minute read

French Bulldog Breed Guide

Spotted Great Dane in sunshine
6 minute read

Great Dane Breed Guide

Woman walking Pug dog
7 minute read

Pug Breed Guide

Boston Terrier with wrinkles laying on the floor
3 minute read

11 Photos of Dogs to Help You Make It Through Monday

Man giving high five to yellow Labrador Retriever
7 minute read

What Is Preventive Care?

Dachshund acting like a ventriloquist dummy
2 minute read

8 Hilarious Dog TikTok Accounts to Make You Laugh

French bulldog with upset stomach laying on ground
10 minute read

Remedies for Upset Stomach in Dogs

Cat with blue eyes and blue collar
5 minute read

Probiotics For Cats

Gray cat receiving pet and appearing to be sick
8 minute read

Constipation in Cats

Cat stepping out of litter box
7 minute read

Diarrhea in Cats

White Standard Poodle standing in yard
8 minute read

Poodle Dog Breed Guide

Dog on the beach
6 minute read

Summer Essentials for Dogs

Small dog in carrier receiving a shot
11 minute read

What Vaccines Do Dogs Need?

White dog looking at bowl of vegetables
11 minute read

What Vegetables Can Dogs Eat?

Vet examining a dog near a woman wearing a face covering
8 minute read

Should I Take My Pet to the Emergency Room?

Golden Retriever has dry nose
6 minute read

Why Is My Dog's Nose Dry?

person wrapping a dog's paw with gauze
14 minute read

Top 10 Items To Put In A Dog First Aid Kit

Dalmatian dog eating fruits on table
12 minute read

What Fruits Can Dogs Eat?

Cat drinking milk from a bowl outside
6 minute read

Can Cats Drink Milk?

Cat Near Bananas on Counter
5 minute read

Can Cats Eat Bananas?

Cat staring at food on the floor
16 minute read

Human Foods Cats Can and Can't Eat

Dog eating a blade of grass laying down in a field
6 minute read

Why Is My Dog Eating Grass?

Cat sniffing a branch of an apple tree
7 minute read

Can Cats Eat Apples?

Cat eating corn from a bowl on the floor
7 minute read

Can Cats Eat Corn?

woman in rain coat petting dog
7 minute read

Pet Emergency Kit Checklist

Cat eating from green bowl
6 minute read

Can Cats Eat Avocado?

Cat trying to get vegetables off counter
5 minute read

Can Cats Eat Carrots?

Cat eating cheese
7 minute read

Can Cats Eat Cheese? Here’s Everything You Need to Know

Brown pointer dog resting head on the ground
7 minute read

Blastomycosis in Dogs: Symptoms, Treatment & Prevention

Rescue dog swimming in water
3 minute read

10 Inspiring Photos of Heroic Dogs Caught in the Act

Orange long-haired house cat resting on post
3 minute read

10 Photos of Cats Being Household Heroes

Cat eating rice off counter
6 minute read

Can Cats Eat Rice?

Pet cat looking over owner's shoulder
12 minute read

Cat Health Issues

Black Cavalier King Charles Spaniel dog sits on toilet
12 minute read

Diarrhea in Dogs: Causes, Treatments, Prevention

Mother cat and her newborn kitten
2 minute read

10 Heartwarming Photos of Mamma Cats & Their Kittens

Dog licking puppy's face
2 minute read

10 Adorable Pics of Mamma Dogs & Their Puppies

Cat staring at a bowl of grapes
4 minute read

Cat Cats Eat Grapes?

Beagle dog nursing her puppies outdoors
6 minute read

Mastitis In Dogs: Symptoms, Causes, & Treatment

Large dog laying on vet table licking owner's hand
7 minute read

Osteosarcoma (Bone Cancer) in Dogs: Causes, Symptoms, Treatment

Dog wants to eat fruit dessert plate on table
12 minute read

List of Food Dogs Can (and Can't) Eat, According to Vet

Garlic peeled and diced on cutting board
6 minute read

Can Dogs Eat Garlic? Here's Everything You Need to Know

American Foxhound dog tilting head
6 minute read

Ataxia in Dogs: Causes, Symptoms, and Treatment

Dog with conjunctivitis eye problem
6 minute read

Conjunctivitis (Pink Eye) in Dogs: Causes, Symptoms, Treatment

White cat cleaning rear end with tongue
5 minute read

Tapeworms in Cats: Causes, Symptoms, Treatment

Brown Labrador Retriever puppy laying on grass
31 minute read

Labrador Retriever Growth & Weight Chart: Everything You Need To Know

Basset Hound puppy sitting outside in sun
7 minute read

Basset Hound Growth & Weight Chart: Everything You Need to Know

Havanese puppy with black and white spots
6 minute read

Havanese Growth & Weight Chart: Everything You Need to Know

Maltese puppy close-up
7 minute read

Maltese Growth & Weight Chart: Everything You Need To Know

Pomeranian puppy standing in grass
8 minute read

Pomeranian Growth & Weight Chart: Everything You Need to Know

Back to Blog
A family with pets that are insured by Pawlicy Advisor
Pawlicy Advisor is the leading independent marketplace for finding the best coverage for your pet at the lowest rate.
Join 2,438,795+ insured dogs and cats across the US.
Get a Quote
Our pet insurance partners
ASPCA Pet Health Insurance Logo
Pets Best Pet Insurance Logo
Embrace Pet Insurance Logo
Pumpkin Pet Insurance Logo
MetLife Pet Insurance Logo
Prudent Pet Insurance Logo