Understanding Heart Murmurs in Dogs
Heart murmurs in dogs are abnormal heart sounds that can be detected by listening to the heart with a stethoscope. They can be caused by turbulent blood flow within the heart, either due to a structural problem within the heart itself (cardiac disease) or an extracardiac problem not caused by heart disease. Understanding the definition and detection of heart murmurs, as well as their grading, is essential for dog owners.
Definition and Detection
A heart murmur is an abnormal sound that can be heard during a heartbeat. It is typically described as a whooshing or swishing sound. Heart murmurs in dogs are classified based on their intensity and timing. They are graded on a scale of I to VI, with Grade I being very soft and Grade VI being very loud, heard throughout the chest.
To detect a heart murmur in a dog, a veterinarian will listen to the heart using a stethoscope during a physical examination. The presence of a heart murmur does not necessarily indicate a serious health issue, as innocent or physiologic heart murmurs are common in young puppies, especially large breed puppies. These murmurs have no impact on the dog’s health and typically appear around 6-8 weeks of age. They often outgrow by 4-5 months of age (VCA Canada).
Grading Heart Murmurs
Grading heart murmurs helps veterinarians assess the intensity and potential impact of the murmur. However, it’s important to note that the loudness of a heart murmur does not always correlate directly with the severity of the disease. Here is a breakdown of the grading system for heart murmurs in dogs:
| Grade | Description |
|---|---|
| I | Very soft, barely audible |
| II | Soft, but easily heard |
| III | Moderately loud |
| IV | Loud, with palpable thrill (vibration) |
| V | Very loud, with a palpable thrill |
| VI | Very loud, heard everywhere that the heart can be heard |
Murmurs that are grade 3 or higher should be evaluated by a veterinary cardiologist as soon as possible to determine the underlying cause and appropriate treatment (University of Illinois College of Veterinary Medicine). Early detection and treatment can significantly improve the prognosis for dogs with heart murmurs.
- Incredible Value: Give your pup the gut health and allergy support they deserve while enjoying our best-selling chews at an incredible value with this exclusive 2-pack
- America's #1 Selling Probiotic for Dogs: PetLab Co.’s premium quality dog probiotics were the top-selling dog health supplement on Amazon in 2022. And owners across America are loving the benefits
- Support for Paw Licking, Itchy Skin & Healthy Yeast Levels: Each tasty probiotic chew is formulated with prebiotics and probiotics. Including 8 strains of beneficial bacteria to support the immune system and dog’s seasonal allergies
- Digestive Health: This probiotic supplement also contains Inulin (a prebiotic for dogs) and Pumpkin for dogs to support digestive health and help counter occasional diarrhea and constipation
- Manufactured in the USA & NASC Certified: Our mission is to ensure the very best quality through research and rigorous production practices. All our dog health supplies are manufactured in the USA using ingredients sourced from prime locations in the US & worldwide
Understanding the definition, detection, and grading of heart murmurs is crucial for dog owners. Regular veterinary check-ups and monitoring are essential to identify any potential heart issues in dogs. In the following sections, we will explore the different types, causes, diagnosis, treatment options, and preventive measures for heart murmurs in dogs.
Types of Heart Murmurs in Dogs
When it comes to heart murmurs in dogs, there are two main categories: innocent murmurs and pathologic murmurs. Understanding the distinction between these types of murmurs is essential for proper diagnosis and treatment.
Innocent Murmurs
Innocent murmurs, also known as physiologic murmurs, are common in young puppies, particularly large breeds. They typically appear around 6-8 weeks of age and are considered benign. These murmurs are usually of low intensity, ranging from Grade I to II out of VI in terms of loudness. Innocent murmurs are harmless and have no impact on the dog’s health.
Most innocent murmurs in puppies resolve on their own by around 4-5 months of age (VCA Canada). These murmurs are considered a normal part of the puppy’s development and do not require specific treatment or intervention. It’s important to note that innocent murmurs should not be confused with pathologic murmurs, which are associated with underlying heart conditions.
Pathologic Murmurs
Pathologic murmurs are murmurs that are caused by heart disease or other cardiovascular abnormalities. Unlike innocent murmurs, pathologic murmurs can occur at any age, including in older dogs (VRCC). They are typically louder and may be associated with other symptoms or signs of heart problems, such as coughing, exercise intolerance, or lethargy.
Diagnosing pathologic murmurs usually requires additional diagnostic testing, such as an echocardiogram, to evaluate the structure and function of the heart. The underlying cause of the murmur will determine the appropriate treatment approach, which may include medications, dietary management, or surgical interventions.
If your dog has a heart murmur, it is crucial to consult with a veterinarian for a proper diagnosis and guidance on the best course of action. Regular monitoring and follow-up appointments are essential to assess the progression of the murmur and ensure your dog’s well-being. For older dogs with heart murmurs, additional considerations may be necessary to manage their specific needs and maintain their quality of life.
By understanding the different types of heart murmurs, dog owners can work closely with their veterinarians to provide the appropriate care and support for their furry companions.
Causes of Heart Murmurs
Heart murmurs in dogs can be caused by various factors, including congenital heart defects and acquired heart conditions. Understanding these causes is essential in determining the appropriate treatment and management for dogs with heart murmurs.
Congenital Heart Defects
Congenital heart defects are abnormalities in the structure of the heart that are present at birth. These defects can disrupt the normal flow of blood, leading to the development of heart murmurs. Some of the most common congenital heart defects seen in puppies include:
-
Patent Ductus Arteriosus (PDA): In this condition, a blood vessel called the ductus arteriosus, which is supposed to close after birth, remains open. This causes abnormal blood flow between the aorta and the pulmonary artery. If left untreated, it can lead to heart enlargement and congestive heart failure. Closure of the PDA can be performed through surgery or minimally invasively by a cardiologist.
-
Pulmonic Stenosis: Pulmonic stenosis is characterized by a narrowing of the pulmonary valve or the artery leading to the lungs. This obstruction disrupts the flow of blood from the right ventricle to the lungs. Small-breed dogs and bulldogs are more prone to this condition. Balloon valvuloplasty, a minimally invasive procedure, can be performed to resolve this stenosis.
-
Subaortic Stenosis: Subaortic stenosis involves a narrowing below the aortic valve, obstructing the flow of blood from the left ventricle to the aorta. Large-breed dogs are more prone to this condition. Balloon valvuloplasty can also be performed to resolve subaortic stenosis.
Early detection and evaluation of congenital heart defects are crucial for improving long-term outcomes. Veterinary cardiologists can assess and provide appropriate treatment options for dogs with these conditions. The cardiology service at the University of Illinois Veterinary Teaching Hospital even offers discounted prices for screening litters of puppies for heart murmurs, emphasizing the importance of early detection.
Acquired Heart Conditions
Acquired heart conditions are those that develop over time due to factors such as age, disease, or other underlying health issues. While congenital heart defects are present at birth, acquired heart conditions develop later in a dog’s life. Some common causes of acquired heart conditions that can lead to heart murmurs include:
-
Heart valve disease: Degenerative changes in the heart valves can lead to murmurs. The most common valve disease in dogs is degenerative mitral valve disease.
-
Cardiomyopathy: Cardiomyopathy refers to diseases that affect the structure and function of the heart muscle. It can cause abnormalities in the heart’s pumping ability and lead to murmurs.
-
Heartworm disease: Heartworms are parasitic worms that can inhabit a dog’s heart and blood vessels. The presence of heartworms can disrupt normal blood flow and contribute to the development of heart murmurs.
-
Infection: Bacterial infections, such as endocarditis, can affect the heart valves and lead to murmurs.
-
Other systemic diseases: Certain systemic conditions, such as high blood pressure or thyroid disease, can also contribute to the development of heart murmurs in dogs.
It’s important to note that heart murmurs in older dogs may have different causes compared to heart murmurs in puppies. Proper diagnosis and evaluation by a veterinarian are essential in determining the underlying cause of the heart murmur and guiding appropriate treatment (University of Illinois College of Veterinary Medicine).
Diagnosis and Prognosis
When it comes to diagnosing and assessing the prognosis of a heart murmur in dogs, several diagnostic tests and factors come into play. It’s important to understand the diagnostic testing methods and prognosis factors to effectively manage your dog’s condition.
Diagnostic Testing
To determine the presence and severity of a heart murmur in dogs, veterinarians may utilize various diagnostic tests. These tests can include:
- X-rays: X-rays provide a detailed image of the heart and lungs, allowing veterinarians to assess the size and shape of the heart chambers and detect any abnormalities.
- Electrocardiogram (ECG): An ECG records the electrical activity of the heart, helping to identify irregular heart rhythms and abnormalities that may contribute to the heart murmur.
- Echocardiogram: An echocardiogram uses ultrasound technology to create images of the heart’s structure and function. This non-invasive test helps pinpoint the location of the turbulence causing the murmur and provides valuable information about the overall health of the heart.
These diagnostic tests help veterinarians determine the underlying cause of the heart murmur and evaluate the overall cardiac health of the dog. The results of these tests guide the management and treatment plan for the dog.
Prognosis Factors
When assessing the prognosis of a dog with a heart murmur, several factors come into play. These factors include:
- Severity of the murmur: Heart murmurs are graded on a scale from I to VI, with higher grades indicating more significant abnormalities. The higher the grade, the more likely it is that the dog may experience symptoms or complications.
- Underlying cause: The cause of the heart murmur plays a significant role in determining the prognosis. Some causes, such as congenital heart defects, may require surgical intervention, while others, such as acquired heart conditions, may be managed with medication and lifestyle changes (heart murmurs in dogs).
- Response to treatment: The dog’s response to treatment and management strategies can also influence the prognosis. Regular monitoring and follow-up visits with the veterinarian are crucial to assess the dog’s response to treatment and make necessary adjustments.
- Overall health of the dog: The dog’s overall health, including age, general well-being, and the presence of other underlying medical conditions, can impact the prognosis. Older dogs may have additional challenges in managing heart murmurs.
It’s important to note that the prognosis for dogs with heart murmurs can vary. With proper management, including appropriate treatment, monitoring, and lifestyle modifications, many dogs can lead happy and fulfilling lives.
To support the overall cardiac health of dogs with heart murmurs, specialized diets may be recommended. Sodium-restricted prescription diets, such as Purina’s Pro Plan Veterinary Diet CardioCare, Hill’s Prescription Diet Heart Care h/d, and Royal Canin Veterinary Diet Early Cardiac, can help prevent fluid accumulation, support healthy blood pressure, and provide nutrients that aid in cardiac function. Consulting with a veterinarian and following their guidance is crucial in managing and caring for a dog with a heart murmur.
Treatment Options for Heart Murmurs
Management Approaches
When it comes to treating heart murmurs in dogs, the approach depends on the underlying cause, severity, and overall health of the dog. In many cases, heart murmurs in puppies go away on their own as they grow and develop. Most murmurs are innocent and do not require treatment, especially if they are low-grade.
However, if a heart murmur is grade 3 or higher, it is important to consult a veterinary cardiologist for further evaluation and treatment. Early detection and appropriate management significantly improve the prognosis for the dog.
In cases where an underlying congenital heart defect is diagnosed, management approaches may include medication to control symptoms, such as diuretics to reduce fluid buildup or medications to improve heart function. Regular monitoring and follow-up visits with a veterinarian are crucial to assess the progress and adjust the treatment plan as needed.
Surgical Interventions
In some cases, surgical intervention may be necessary to address certain congenital heart conditions that cause heart murmurs in dogs. For example, patent ductus arteriosus (PDA) is a condition where a blood vessel fails to close after birth, leading to heart enlargement and potential heart failure. Closure of the PDA can be performed through surgery or minimally invasively by a cardiologist.
Other conditions, such as subaortic stenosis in large-breed dogs or pulmonic stenosis in small-breed dogs and bulldogs, may require intervention. These conditions may cause weakness or collapse in dogs after intense activity due to inadequate blood flow to the brain. A minimally invasive procedure called a balloon valvuloplasty can be performed to resolve these stenoses.
It’s important to note that surgical interventions are typically performed by veterinary specialists, such as veterinary cardiologists, who have expertise in diagnosing and treating heart conditions in dogs. These procedures aim to improve blood flow and reduce the impact of the heart murmur on the dog’s overall health and well-being.
If your dog has been diagnosed with a heart murmur, it is essential to work closely with your veterinarian and any necessary specialists to determine the best course of treatment. Regular check-ups and ongoing monitoring are crucial to ensure the dog’s condition is properly managed and any necessary adjustments to the treatment plan are made.
Preventive Measures and Care
When it comes to heart murmurs in dogs, preventive measures and ongoing care are essential to ensure the well-being of your furry friend. Monitoring and follow-up, along with dietary support, play significant roles in managing heart murmurs in dogs.
Monitoring and Follow-Up
Regular monitoring and follow-up are crucial for dogs with heart murmurs. It is recommended to schedule regular veterinary check-ups to assess the progression of the condition and evaluate the overall cardiac health of your dog. These check-ups may include auscultation (listening to the heart sounds using a stethoscope), as well as diagnostic tests like echocardiograms, which provide detailed information about the structure and function of the heart (Cornell University College of Veterinary Medicine).
Echocardiograms are non-invasive and serve as crucial diagnostic tools to confirm the diagnosis, establish baseline cardiac function, and monitor any changes in the heart’s structure and function. Regular monitoring allows veterinarians to tailor treatment plans and make necessary adjustments to ensure the best care for your dog.
Dietary Support
Diet plays a significant role in supporting the overall cardiac health of dogs with heart murmurs. Certain prescription diets are formulated to provide specific nutrients and support cardiac function. These diets are sodium-restricted and help prevent fluid accumulation, support healthy blood pressure, and aid in the overall well-being of dogs with heart murmurs. Some examples of sodium-restricted prescription diets include Purina’s Pro Plan Veterinary Diet CardioCare, Hill’s Prescription Diet Heart Care h/d, and Royal Canin Veterinary Diet Early Cardiac (Cornell University College of Veterinary Medicine).
It’s important to consult with your veterinarian to determine the most suitable dietary approach for your dog based on their specific needs and the severity of the heart murmur. A balanced and nutritious diet, along with appropriate dietary support, can help optimize your dog’s overall health and well-being.
Taking preventive measures and providing ongoing care for your dog with a heart murmur is essential for their long-term health. Regular monitoring, including diagnostic tests like echocardiograms, allows for early detection of any changes and ensures appropriate management. Additionally, providing a suitable diet, such as sodium-restricted prescription diets, can support your dog’s cardiac health. By implementing these preventive measures and providing necessary care, you can help your furry companion live a happy and healthy life despite their heart murmur.
