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Heart Murmur in Dogs

A heart murmur in dogs is an abnormal sound heard during a veterinary consultation when the vet listens to the heart with a stethoscope. This sound is caused by turbulence of the blood flow within the heart or into the major blood vessels connected to the heart.

It is important to note that a heart murmur is not a diagnosis, but a clinical finding. In other words, it tells the veterinarian that blood flow is not moving as expected, but it does not explain the cause.

Heart murmurs can be harmless or incidental findings, but they can also be a sign of heart disease. Many dogs with heart murmurs can live comfortably for many years, especially when the murmur is identified early and treated appropriately. Thus, with routine veterinary care and monitoring, a heart murmur does not always mean a poor quality of life for a dog.

Understanding Heart Murmurs in Dogs

In a healthy dog’s heart, blood flows in a smooth, coordinated way, producing regular and quiet “lub-dub” sounds. When blood flow becomes disrupted (due to changes in heart valves, heart chambers, blood characteristics, etc.), it creates a vibration that can be heard as a murmur.

Usually, veterinarians will describe a heart murmur based on their timing, location, and intensity. However, one of the most common features is the intensity, which is categorized into Grade I to Grade VI. Lower-grade murmurs are very soft and may only be detected under ideal conditions. Higher-grade murmurs are louder and easier to hear. However, it is important to note that grading helps guide clinical decisions, but it alone does not determine disease severity. Thus, even a lower-grade murmur may still be associated with underlying heart disease.

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Signs and Symptoms of Heart Murmur in Dogs

Some dogs will not show any symptoms, particularly in the early stages. But, when signs are present, they may reflect how effectively the heart is compensating. For instance:

Early or mild signs:

Symptoms may not be noticeable
Some exercise tolerance
A murmur may be detected during a routine vet visit

Progressive Signs:

Fatigue
Coughing, more at night or after activity
Increased respiratory rate while resting

Advanced signs:

Labored and/or rapid breathing
Collapse and/or weakness
Fluid buildup that can cause abdominal distension (ascites)
Lethargy

Common Causes and Risk Factors

Some of the common causes may include degenerative valve disease, such as mitral valve disease in small and senior dogs, congenital heart defects present from birth, and cardiomyopathies that affect the muscle of the heart and are more commonly seen in larger breeds than small breeds. In some cases, murmurs can be secondary to conditions that are not related to cardiac conditions. For example, anemia, fever, or systemic illness, etc.

How Heart Murmurs in Dogs Are Diagnosed

First, a veterinarian should start with physical examination and auscultation. If a murmur is detected, the vet may request additional diagnostics to try to understand the underlying cause and assess heart function, such as echocardiography (cardiac ultrasound), which is considered the gold standard for evaluating heart structure and function. Chest X-rays may be used to assess heart size and lung health, and electrocardiogram (ECG) can help identify rhythm abnormalities in the heart.

Management and Supportive Care Options

Treatment will depend entirely on the underlying cause and whether the dog is experiencing any clinical signs. It is important to note that not all heart murmurs require medication, and many pets are managed through observation and routine follow-ups with their regular vets.

When treatment is recommended, it may include prescription pharmaceuticals, modifications in activities (exercise), nutritional changes, and supportive care. The goal is to reduce heart workload, support circulation, and maintain the quality of life.

Some supportive nutritional and herbal options may be incorporated as part of a comprehensive care plan. For instance:

NHV Hearty Heart can be used to support normal cardiac function, circulation, and heart muscle health in dogs with murmurs
Omega-3 fatty acids, such as those found in NHV Petomega 3, are well recognized for supporting cardiovascular health
NHV Turmeric may help support a healthy inflammatory response and overall systemic wellness

It is very important to note that these options are intended to support, not replace, veterinary care and should always be discussed with a veterinarian, especially for dogs receiving cardiac medications.

Prognosis and Living Well with a Heart Murmur

Many dogs can live long and happy with heart murmurs. Because of this, early detection is important as it allows for better monitoring and more management options as the condition progresses. Thus, with routine veterinary care, appropriate diagnostics, and individualized support, dogs with heart murmurs can continue to enjoy an excellent quality of life for many years.

Conclusion

Heart murmurs in dogs can vary in cause and significance, and they are clinical findings, not a diagnosis. Awareness combined with regular monitoring is important. Supportive routines, veterinary care, and early detection can make a meaningful difference in long-term outcomes.

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