Heart Murmur in Dogs: Causes, Symptoms & Treatment Options Explained (2025)

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When your vet mentions a heart murmur in dogs, they’re talking about an extra whooshing sound as blood flows through your pup’s heart—kind of like a hiccup in a symphony. This can happen thanks to leaky valves, a heart that’s a little too big for its britches, or even just puppy growing pains.

Some murmurs are harmless, while others need the keen eye of a vet to sort out. Treatment really depends on the cause and severity, but don’t jump to worst-case scenarios. There’s a lot more to managing a dog’s murmur than meets the ear—stay tuned for practical tips.

What is a Heart Murmur in Dogs?

When your dog’s heart makes an unusual whooshing sound, it’s called a heart murmur, which is caused by turbulent blood flow through the heart’s chambers or valves. You mightn’t notice anything at home, but your veterinarian can hear these murmurs with a stethoscope, sometimes making your pup’s heart sound like it’s auditioning for a marching band.

Definition and Explanation

A heart murmur in dogs is basically an unusual sound you hear when the heart pumps blood. Picture your heart’s anatomy as a four-chamber machine, with valves directing blood flow like traffic lights. When these valves don’t work perfectly, you might get whooshing or swishing—those are murmurs.

• Heart murmurs are named by type: physiologic, systolic, or diastolic.
• Valve function is key to smooth blood flow.
• Diagnosis often starts with a vet listening for odd heart sounds.

Trust your vet—they’ve heard it all!

How Heart Murmurs Sound

Imagine you’re sitting quietly with your dog and a vet puts the stethoscope to their chest. Instead of the usual crisp heart tones, you might hear a whooshing or swishing—think of distant laundry in a spin cycle. That’s a heart murmur, created by turbulence noise as blood rushes past valves.

Murmur intensity varies; some are faint like a whispered secret, others loud as a marching band. Audible frequencies and sound patterns help your vet tell a systolic murmur from a diastolic one, sometimes confirmed with an echocardiogram.

Types of Heart Murmurs in Dogs

You’ll hear a lot about different types of heart murmurs in dogs, from those your pup was born with to ones that pop up later in life.

Knowing which kind your dog has can help you work with your vet to keep their tail wagging, even if their heart sounds a little different.

Congenital Murmurs

If your puppy’s first checkup uncovers a murmur, congenital defects might be at play. These are structural quirks present from birth, such as heart valve issues or abnormal openings. Some murmurs fade as puppies grow, but others may stick around.

• Can affect any breed
• Linked to genetic testing results
• Related to Puppy Murmur grades
• May involve Mitral Valve Disease
• Needs ongoing murmur diagnosis

Acquired Murmurs

Over the course of a dog’s life, you might hear your vet mention acquired murmurs—often traced to valve disorders like mitral valve disease or heart enlargement. As dogs age, these cardiac conditions develop from wear and tear.

Murmur grading helps guide care, ranging from mild to serious. Treatments include cardiac medications, with ongoing canine cardiology checkups to monitor for progressive heart valve disease.

Innocent or Physiologic Murmurs

If you’ve just read about acquired murmurs, you might wonder why some dog heart murmurs sound less alarming. These innocent or physiologic heart murmurs—often called “puppy heart” sounds—are common.

Think of them as normal variations caused by rapid growth. Murmur grades here are mild, and most innocent murmurs simply fade as your young dog matures.

What Causes Heart Murmurs in Dogs?

You might be surprised to learn your dog’s heart murmur could stem from leaky heart valves, congenital defects, or even a stretched-out heart muscle. While these names sound intimidating, understanding the root causes can help you work closely with your veterinarian and keep your dog wagging a little longer.

Valve Disorders

In the context of heart murmurs, heart valve disease plays a starring role. Mitral valve disease, or mitral insufficiency, is a common culprit—think of it as a leaky faucet causing heart failure over time.

Aortic stenosis is another troublemaker. Sometimes, valve repair or even cardiac surgery is needed if issues like mitral regurgitation threaten your dog’s health.

Congenital Heart Defects

During fetal development, some puppies can be born with congenital heart defects—thanks to genetic factors or unexpected cardiac malformations. In canine cardiology, issues like mitral valve disease or improper closures are big reasons for a heart murmur in young dogs.

Pediatric cardiology experts watch for these changes to keep your dog’s heart health on the right track.

Heart Enlargement

When your dog’s heart works overtime, cardiac hypertrophy—heart muscle thickening—can pop up, leading to an enlarged left ventricle or full-blown cardiomegaly. This puts extra strain on the heart, raising heart murmur risks.

An echocardiogram helps unravel the mystery behind heart enlargement.

Extracardiac Causes

Sometimes, things outside the heart—like anemia effects, blood clots, or respiratory issues—can stir up a heart murmur. Systemic diseases and certain nutritional factors may also put your pet’s ticker in turbulence.

Keeping up with good dog care, regular checkups, and informed decisions in veterinary medicine strengthen your canine cardiology knowledge and your dog’s health. A well-planned heart healthy diet is essential for maintaining your dog’s overall cardiovascular well-being.

Heart Murmurs in Puppies

When your puppy’s heart makes an unexpected sound, it can be both confusing and a little nerve-wracking. **Many young dogs experience harmless murmurs as their bodies grow.

**

Still, it’s smart to have your veterinarian check any murmur, just in case that little engine is doing more rumbling than it should.

Physiologic or ‘Puppy’ Murmurs

Many young pups develop what veterinarians call physiologic heart murmurs during Puppy Development Stages. These innocent sounds occur because puppies have thicker blood and rapidly growing hearts that create temporary turbulence. Unlike concerning murmurs, physiologic heart murmur episodes don’t signal underlying disease in Canine Cardiology.

Your vet can distinguish these benign sounds during Heart Murmur Diagnosis by their soft grade and timing. Most puppy murmurs disappear by six months as Heart Growth Factors stabilize and blood consistency normalizes.

Regular checkups support ideal Puppy Heart Health monitoring. While Murmur Prevention isn’t always possible, these developmental murmurs represent normal Dog Heart Health variations rather than pathological conditions requiring intervention.

When Murmurs Are Concerning

While puppy murmurs often resolve naturally, certain red flags demand immediate veterinary attention. Heart Murmur Diagnosis becomes essential when you notice concerning signs alongside the murmur. Cardiac Monitoring helps distinguish between innocent sounds and Pathological Murmurs that threaten your pup’s future.

Watch for these warning signs that indicate Murmur Severity requires intervention:

1. Persistent coughing or labored breathing
2. Exercise intolerance or fatigue during play
3. Poor growth rate compared to littermates
4. Blue-tinged gums or tongue
5. Murmur Timing that occurs during heart relaxation (diastolic)

Cardiac Disease in Dogs progresses differently in puppies, making early detection imperative. Congestive Heart Failure can develop rapidly if underlying defects aren’t addressed. Your vet’s expertise in evaluating Canine Prognosis ensures proper treatment timing.

Symptoms of Heart Murmurs in Dogs

You’ll notice your dog’s heart murmur symptoms before you hear the murmur itself, since most pet parents don’t carry stethoscopes around.

While some dogs show no signs at all, others develop telltale symptoms like persistent coughing, difficulty breathing during normal activities, or getting winded after short walks.

Coughing and Breathing Issues

Persistent coughing and breathing difficulties often signal that your dog’s heart murmur has progressed to congestive heart failure. These respiratory symptoms occur when fluid accumulates in the lungs due to poor cardiac function. Watch for wet-sounding coughs, especially at night, and labored breathing patterns that worsen with activity.

Symptom	What You’ll Notice
Wet Cough	Sounds like your dog is trying to clear phlegm, often worse at night
Rapid Breathing	Over 30 breaths per minute while resting
Open-Mouth Breathing	Panting when not hot or after exercise
Restlessness	Can’t get comfortable, especially when lying down
Blue Gums	Indicates severe oxygen shortage requiring emergency care

Cardiomyopathy and other dog heart diseases can cause airway obstruction through lung inflammation. If coughing fits become frequent or breathing difficulties worsen, contact your veterinarian immediately. Canine cardiac care focuses on preventing respiratory failure through proper monitoring and treatment.

Exercise Intolerance

Exercise intolerance becomes your dog’s way of saying "I can’t keep up anymore." Dogs with heart murmurs often tire quickly during walks, choosing to sit or lie down mid-activity. These exercise limits signal breathing difficulties as the compromised heart struggles to pump oxygen efficiently.

Physical restrictions may require activity modifications, transforming your once-energetic companion into a couch potato who prefers shorter, gentler adventures. Owners can explore gentle exercise options to help their dogs stay active while managing their condition.

Fainting and Weakness

Fainting and weakness represent serious warning signs that your dog’s heart murmur may be progressing to congestive heart failure or dilated cardiomyopathy. These collapse episodes require immediate canine cardiac care and prompt dog heart murmur treatment.

These episodes often occur when your dog’s compromised heart can’t pump enough blood to meet increased oxygen demands.

How Veterinarians Detect Heart Murmurs

When you bring your dog to the vet, they’ll use a stethoscope to listen carefully to your pet’s heart during the physical exam.

Your veterinarian will then grade any detected murmur on a scale from I to VI, with Grade I being barely audible and Grade VI being loud enough to feel vibrations through the chest wall.

Physical Exam and Stethoscope

Your veterinarian uses a stethoscope to detect heart murmurs during routine physical exams. This essential diagnostic tool amplifies your dog’s heartbeat, allowing the veterinarian to identify abnormal sounds through careful auscultation methods.

During heart sound analysis, they’ll listen to different areas of your dog’s chest, positioning the stethoscope over specific valve locations. The veterinarian evaluates murmur intensity and timing within the cardiac cycle, noting any whooshing sounds that indicate turbulent blood flow.

This initial assessment determines whether additional tests like an echocardiogram are necessary for diagnostic accuracy.

Grading Heart Murmurs

Once your vet detects a heart murmur with their stethoscope, they’ll assign it a grade based on murmur intensity. Heart Murmur Grades range from I to VI, measuring how loud the heart sounds appear during examination.

Grade I murmurs are barely audible whispers, while Grade VI murmurs can be felt as vibrations through your dog’s chest wall. This grading system helps determine murmur timing and assess valve function problems.

Higher grades often indicate greater turbulence effects within the heart chambers. Your vet may recommend an echocardiogram for grades III and above to better understand the underlying cause of these abnormal heart murmurs.

Diagnostic Tests for Heart Murmurs

Once your vet detects a heart murmur, you’ll need specific diagnostic tests to determine what’s causing it and how serious it might be. These tests help your veterinarian create the right treatment plan and give you a clear picture of your dog’s heart health.

Echocardiogram

An echocardiogram acts as the benchmark for canine cardiac care, providing detailed images of your dog’s heart structure and function. This specialized ultrasound reveals what’s really happening inside your pet’s ticker.

• Echocardiogram Types: 2D imaging shows heart chambers while Doppler measures blood flow patterns
• Image Interpretation: Veterinarians assess valve function, chamber size, and muscle thickness
• Procedure Details: Non-invasive test usually takes 20-30 minutes with gentle restraint
• Cost Factors: Ranges from $300-800 depending on location and complexity
• Alternative Imaging: CT scans available but echocardiography remains preferred for heart murmur treatment

Additionally, veterinarians may use a heart diagnostic tool to identify heart problems in dogs.

Chest X-Rays

Chest X-rays reveal your dog’s heart size and shape through diagnostic imaging. Your veterinarian examines the cardiac silhouette and lung field during radiograph analysis.

X-ray imaging detects heart enlargement and fluid buildup in lungs, key signs of congestive heart failure linked to heart murmur progression requiring immediate attention.

Electrocardiogram (ECG)

An electrocardiogram tracks your dog’s electrical activity and heart rhythm during cardiac monitoring. This non-invasive test helps vets spot arrhythmias that might accompany murmurs.

ECG interpretation reveals whether your dog’s heart beats normally or shows concerning patterns.

Signal analysis from electrocardiograms guides treatment decisions, especially when combined with stethoscope findings and echocardiography results.

Blood Tests

Blood Analysis becomes your veterinarian’s detective tool when investigating heart murmurs. Serum Chemistry and Hematology Tests reveal underlying conditions that might cause or worsen cardiac disease, while Cardiac Biomarkers measure heart muscle stress.

• Screen for anemia, infections, and heartworm disease affecting pet health
• Measure proBNP levels to assess heart failure severity
• Check kidney and liver function before starting heart medications

These Biochemical Markers help your vet rule out non-cardiac causes and guarantee your dog’s body can handle treatment.

Treatment Options for Heart Murmurs

Your dog’s treatment options depend entirely on what’s causing the murmur, ranging from simple monitoring to life-saving medications or surgery.

While innocent puppy murmurs need no intervention, pathologic murmurs often require cardiac medications to support heart function and reduce fluid buildup, or surgical correction for congenital defects like patent ductus arteriosus.

When No Treatment is Needed

Not all heart murmurs require treatment. Innocent murmurs in puppies often disappear by sixteen weeks without intervention. Many asymptomatic dogs with mild cases live normal lives through regular monitoring alone. These benign conditions represent normal variations in heart sounds rather than disease.

Your vet will distinguish between innocent murmurs and pathological murmurs requiring active dog heart murmur treatment to maintain ideal heart health. Understanding heart disease causes is vital for effective treatment and management of the condition.

Medications and Supportive Care

When medication therapy becomes necessary, your vet will prescribe targeted cardiac drugs for symptom management. Dog heart murmur treatment focuses on three main supportive care approaches:

1. Inodilators like pimobendan – These cardiac treatment options strengthen heart contractions while reducing workload
2. Diuretics including furosemide – Remove excess fluid to prevent heart failure progression
3. Angiotensin inhibitors – Support smoother blood flow and reduce cardiac strain

These medications work together to manage your dog’s condition effectively. Effective dog heart medication is vital for maintaining your dog’s health.

Surgery for Correctable Defects

When standard medications can’t fix the problem, surgical repair offers hope for dogs with correctable heart defects. Cardiac surgery specialists can repair congenital issues like patent ductus arteriosus through minimally invasive procedures.

For severe mitral insufficiency, transcatheter edge-to-edge repair provides promising results with 80% survival rates.

Postoperative care requires careful monitoring, but defect correction can dramatically improve your dog’s quality of life.

Prognosis and Life Expectancy

Your dog’s prognosis depends entirely on what’s causing the murmur. The difference between innocent and pathologic murmurs can mean the difference between a normal lifespan and ongoing health management.

While innocent puppy murmurs usually resolve on their own with excellent outcomes, dogs with underlying heart disease face variable prognoses. These depend on the specific condition’s severity and your veterinarian’s treatment plan.

Benign Vs. Pathologic Murmurs

Your veterinarian’s murmur classification determines whether your dog needs immediate attention or simply monitoring. Innocent Murmurs represent normal blood flow variations that don’t indicate heart valve issues or structural problems. These benign sounds often disappear as puppies mature.

Pathological Murmurs signal actual heart disease, with turbulence causes ranging from mitral regurgitation to congenital defects. Murmur severity doesn’t always correlate with disease progression, creating diagnostic challenges for veterinarians. A grade VI murmur might be innocent, while a soft grade II could indicate serious heart murmurs requiring treatment.

Factors Affecting Prognosis

Several key elements usually determine your dog’s outlook when facing Canine Heart Disease. Age factors play a vital role, as younger dogs often respond better to treatment outcomes than senior pets. Breed risks substantially influence prognosis, with certain breeds predisposed to specific conditions like Dilated Cardiomyopathy or Heart Valve Disease.

Understanding dog breed lifespans is essential for anticipating potential health issues. Your veterinarian will assess these variables to provide realistic expectations about your pet’s quality of life and longevity.

Home Care and Monitoring for Dogs

You’ll play a vital role in your dog’s ongoing care by monitoring key symptoms and maintaining regular veterinary checkups.

Effective home management includes tracking your pet’s breathing rate, watching for exercise intolerance, and ensuring consistent medication administration when prescribed.

Tracking Symptoms at Home

Monitoring your dog’s heart health at home becomes your daily detective work. Symptom logging helps you spot changes before they become serious problems. You’ll track breathing rates, watch exercise limits, and manage weight carefully. Using a dog stethoscope can be an essential tool for monitoring heart sounds.

What to Track	Normal Range	Red Flags
Breathing Rates	10-30 breaths/min	Over 40 breaths/min
Exercise Limits	Normal activity	Can’t walk a block
Weight Management	Steady weight	Rapid gain/loss

Use a stethoscope if comfortable, noting any changes in your dog’s heart murmur sounds during rest.

Veterinary Follow-Up and Monitoring

Your veterinarian will schedule Regular Checkups every three to twelve months based on your dog’s condition. These Follow-Up Care appointments allow for Ongoing Assessment of heart murmur progression through physical exams and diagnostic tests.

Monitoring Progress helps your vet adjust treatment plans as needed. Veterinary Guidance during these visits ensures ideal Pet Care and Monitoring for your dog’s long-term health.

Regular use of heart rate monitors can provide valuable insights into a dog’s cardiovascular health.

Medication Management

Proper medication management forms the backbone of successful heart disease treatment in dogs. You’ll need to maintain strict medication adherence, giving doses at consistent times daily.

Watch for side effects like decreased appetite or lethargy, and report these to your veterinary care team immediately. Never adjust doses without professional guidance, as drug interactions can affect treatment efficacy in congestive heart failure cases.

Understanding benadryl for dogs is vital for pet owners to guarantee safe administration of this common medication.

Frequently Asked Questions (FAQs)