Heart murmurs in dogs may be identified during routine exams when a veterinarian uses a stethoscope to listen to a dog's heart. If your dog has a heart murmur, instead of hearing the usual "lub-dub" sound, your vet may hear a "whoosh" sound. Not all causes of dog heart murmurs are a cause for concern; however, if your vet notices one in your dog, it's important to know what's causing the murmur and whether the condition needs to be treated. Here's more on what heart murmurs are, what causes them and how they can be treated.
When your veterinarian listens to your dog's heart with a stethoscope, part of what they listen for is a classic "lub-dub" sound that suggests that your dog's heart valves are opening and closing properly. These heart valves open and close in a synchronized manner that allows blood to be pumped to the lungs and the rest of the body without ever flowing in the wrong direction. However, whenever blood flows the wrong direction through the heart, which can be due to things such as impaired heart valve function or heart muscle defects, vets will hear this as a turbulent "whoosh" sound, also known as a heart murmur.
Vets identify heart murmurs based on the intensity of what they hear when they listen to the heart — a "1" rating would indicate the softest murmur while a "6" would be rated as the loudest. However, the volume of the murmur has no correlation with the severity of the condition causing the murmur; it's simply one method that vets use to record the murmur over time to see if it changes.
While heart murmurs may be indicative of heart disease or other conditions, they aren't always a cause for concern. For example, puppies may have an "innocent heart murmur" that they're born with. But, once they're about four months old, the murmur disappears without any treatment. In contrast, a heart murmur in a senior dog may be due to a valve disease, requiring vet treatment and monitoring. Depending on the cause of the heart murmur, your vet may elect to monitor your dog or may recommend additional testing and treatment.
Anything that causes abnormal blood flow within the heart can cause a murmur. Here are the most common causes of heart murmurs in dogs:
Unless a dog is experiencing heart failure, there are often no signs associated with heart murmurs in dogs. In fact, many dog parents are surprised when their vet detects a heart murmur during a routine physical exam. If a dog has been diagnosed with a heart murmur, be aware of the clinical signs of heart failure, which can include:
If you notice your dog showing any of these clinical signs, call your vet for advice immediately.
If your vet hears a murmur when they listen to your dog's heart, be prepared for additional testing. The most common test is a chest X-ray. This allows your vet to look at your dog's heart, lungs and pulmonary vessels, and it may assist in a diagnosis. However, only an echocardiogram (ultrasound of the heart) can confirm the source of a heart murmur as well as the characterization of the severity of the heart disease present. Additional tests that may be recommended based on your dog's individual case include bloodwork (internal organ function screen, complete blood count and heartworm test), blood pressure monitoring and an electrocardiogram (ECG) to check the electrical activity of your dog's heart.
Treatment of heart murmurs in dogs depends on what's causing the murmur and whether it's negatively impacting your dog's life. If your dog isn't showing any signs of heart disease, there may be no treatment recommended. Your vet may elect to monitor your dog every couple of months and only treat your dog if they notice any clinical signs. If your dog was diagnosed with a heart murmur that's caused by a condition that can be corrected surgically, such as a PDA, then surgery will be recommended. If the heart murmur is due to anemia or heartworm disease, then that condition can be treated as well.
Leaky heart valves are managed with medication to help the heart pump blood more effectively. Dogs with many forms of heart disease can live reasonably normal lives as long as you know the signs that indicate your dog's heart needs some help (see above), give medications as prescribed and work with a vet you trust.
While having a heart murmur diagnosed in your dog may sound scary, it doesn't need to be. Many times, your vet can resolve the situation for you or work with you to maximize your dog's health and wellbeing. Your job as the pet parent is to stay informed and continue to bring your furry companion to your vet for routine exams.
Dr. Sarah Wooten graduated from UC Davis School of Veterinary Medicine in 2002. A member of the American Society of Veterinary Journalists, Dr. Wooten divides her professional time between small animal practice in Greeley, Colorado, public speaking on associate issues, leadership, and client communication, and writing. She enjoys camping with her family, skiing, SCUBA, and participating in triathlons.
Supports healthy joints, immune system, digestion, lean muscle & beautiful coat
Clinically proven kibble technology to reduce plaque & tartar build-up
A delicious complement to the nutrition of Science Diet dry dog food
Science Diet's breakthrough nutrition supports ultimate digestive well-being & healthy microbiome
Fewer calories for less active large breed dogs
Delicious braised beef paired with tender vegetables in a succulent stew
Beef & Barley recipe with precisely balanced nutrition to keep adult dogs active and healthy
Vital nutrients to support 5 essential building blocks for lifelong health
Supports digestive health, nourishes skin and promotes a lustrous coat
Improves Everyday Ability to Get Up & Go
Vital nutrients to support 5 essential building blocks for lifelong health
Hill's Science Diet Sensitive Stomach & Skin dry dog food is gentle on stomachs while nourishing skin & promoting a lustrous coat.
Science Diet's breakthrough nutrition supports ultimate digestive well-being & healthy microbiome. Delicious food in a large bite size
Turkey & Barley recipe with precisely balanced nutrition to keep adult dogs active and healthy
Hill's Science Diet Sensitive Stomach & Skin Grain Free dry dog food is gentle on stomachs. Nourishes skin & promotes a lustrous coat.
Delicious roasted chicken paired with tender vegetables in a succulent stew
Supports energy level & beautiful coat. Helps keep immune system, heart & kidneys healthy
Science Diet's breakthrough nutrition supports ultimate digestive well-being & healthy microbiome
Over 70% of dogs lost weight within 10 weeks when fed this nutrition
Learn what to do if your dog is experiencing constipation or an inability to pee. If he isn't going at least twice a day, learn what steps you should take.
Learn how to simply and inexpensively build a DIY dog ramp to help your dog get up & down more easily (great for senior dogs & those with mobility issues).
Discover helpful tips for managing a dog who's afraid of water, how to handle bath time, and how to get them more comfortable with swimming.
Learn about the different classifications between carnivores and omnivores to decide which order dogs fall under.
Learn why some dogs hate baths so much, as well as the importance of bathing and tips for comforting a scared dog when it's time to take a bath.
Understand the common irritants that cause various dog skin conditions, whether they be due to parasites, infections, food, or the environment.
Learn about dwarfism in dogs, including types of this condition, breeds that are prone to developing it & general effects dwarfism has on a dog's health.
Learn what pyoderma in dogs looks like, what causes it and how nutrition & your dog's food can play a role in preventing and treating the infection.
Learn how common tapeworms in a dog are, how to spot the signs of tapeworms on your dog (or in their poop), and tips about prevention & treatment.
Find out if you can feed your dog spicy food or add some spicy flavor to his dog food, and any health implications of doing so.
Discover scenarios where dogs can benefit from shoes or booties in extreme summer heat, including environmental concerns & tips for finding the right ones.
Socializing an older dog is usually more challenging than socializing a puppy. Learn how to overcome the challenges to safely socialize an adult dog.
Learn whether cheese is a snack that's safe for your dog, including specific types of cheese, ingredients to watch for and how much is ideal.
Find out why exercising is so important to your puppy's overall healthy by reading through these 4 helpful facts.
Wondering why your dog is constipated? Or why he has diarrhea? Learn more about these common gastro issues in dogs, and tips for managing them at home.
Learn how to recognize the signs that your puppy is becoming an adult dog, as well as how you can help meet their developmental & nutritional needs.
Learn helpful information about yeast infections in dogs (in both ears & skin), including signs of the condition, causes, treatments and prevention tips.
Discover common reasons why your dog seems afraid of the dark, including things like separation anxiety & traumas, and how to help reduce their fears.
Discover what types of memories dogs actually have, how their memories work & how long they last, and whether they remember details about their owners.
Learn about dog eye boogers, goop, gunk & crustiness: when it's normal vs. when it could be a health concern and which breeds & sizes are most susceptible.
Our low calorie formula helps you control your dog's weight. It's packed with high-quality protein for building lean muscles, and made with purposeful ingredients for a flavorful, nutritious meal. Clinically proven antioxidants, Vitamin C+E, help promote a healthy immune system.
Our low calorie formula helps you control your dog's weight. It's packed with high-quality protein for building lean muscles, and made with purposeful ingredients for a flavorful, nutritious meal. Clinically proven antioxidants, Vitamin C+E, help promote a healthy immune system.
©2025 Hill's Pet Nutrition, Inc. As used herein, denotes registered trademark status in the U.S. only; registration status in other geographies may be different. Your use of this site is subject to the terms of our Legal Statement. About our Ads. Cookie Consent Tool