Heart murmurs in dogs are a relatively common condition, especially in elderly animals. But, contrary to what many people think, a murmur is not a disease in itself. It is a clinical sign: an abnormal sound noticed by the vet during auscultation, which indicates changes in the flow of blood within the heart.
This sound can be associated with both mild conditions and serious heart disease. For this reason, when a heart murmur is diagnosed, the guardian should investigate the cause carefully.
What is a heart murmur?
A healthy heart makes a clear, rhythmic sound ("tum-tum"). A heart with a murmur, on the other hand, produces an additional noise, as if it were "blowing in the wind" between beats. This sound appears when the blood does not flow smoothly through the heart's valves or cavities.
The murmur is classified by the vet in degrees of intensity (from 1 to 6).
It's worth pointing out that a strong murmur doesn't always mean a serious illness, and a slight murmur can hide an important problem. This is why complementary tests are always necessary.
Main causes of heart murmurs in dogs
Heart murmurs can have various origins. In general, it can arise from diseases acquired throughout life, congenital problems (at birth) or other conditions affecting the body.
Acquired diseases
These are the most common causes, especially in adult and elderly dogs:
- Degenerative mitral or tricuspid valve disease (valves that don't close properly, very common in older small dogs).
- Dilated cardiomyopathy (the heart muscle loses strength, more common in large breeds).
- Endocarditis (infection of the heart valves).
- Congestive heart failure (when the heart can no longer pump blood properly).
Congenital heart disease
Defects present from birth, which are often diagnosed in puppies:
- Stenosis (narrowing of the valves or arteries, such as aortic or pulmonary).
- Valve malformations (dysplasia).
- Defects in the septum (abnormal communications between chambers of the heart).
- Persistence of the ductus arteriosus (a channel that should close after birth but remains open).
Other conditions that can cause murmurs
- Anemia (blood circulates faster and more turbulently).
- Hyperthyroidism (speeds up the metabolism and puts a strain on the heart).
- Heartworm disease, transmitted by mosquitoes.
In short, any dog of any age can have a murmur, but it is more common in elderly dogs and in predisposed breeds.
Raças predispostas
Ver raças predispostas
Symptoms that the guardian can observe
Many dogs with mild heart murmurs have no symptoms and live normally. But when the heart disease progresses, the guardian may notice signs such as:
- Dry, persistent cough, often at night.
- Easy fatigue and difficulty keeping up with walks.
- Gasping for breath, even at rest.
- Apathy, less willingness to play.
- Sudden fainting (syncope).
- Purple tongue or gums, a sign of lack of oxygen.
Any of these symptoms warrants immediate veterinary assessment.
How is the diagnosis made?
The diagnosis begins at the consultation, when the vet auscultates the dog's chest and notices the abnormal sound of the murmur.
From there, complementary tests are essential to understand the cause and severity of the alteration and what degree it is.
The most important of these is the echocardiogram, an ultrasound that allows you to observe the functioning of the valves, the chambers of the heart and the flow of blood.
Chest X-rays are also often requested, which show the size and shape of the heart and also make it possible to assess whether there is a build-up of fluid in the lungs.
In some cases, the vet may recommend an electrocardiogram (ECG), which records the heart's electrical activity and helps to identify arrhythmias.
Finally, blood tests complete the investigation, as they provide information about the kidneys, liver and even systemic diseases such as anemia or heartworm disease, which can also cause murmurs.
With all these results in hand, it is possible to determine whether the murmur is merely benign or whether it indicates a disease that needs treatment.
Available treatments
There is no single remedy that can "cure" a heart murmur, because the murmur is just a sign. Treatment seeks to control the underlying heart disease and improve the dog's quality of life and can involve medication, diet and special care.
Never medicate your dog without veterinary advice.
In many cases, specific drugs are prescribed, such as vasodilators, which reduce pressure on the heart; diuretics, which help to eliminate accumulated fluids; and inotropic drugs, which strengthen the contraction of the heart muscle. In more delicate situations, antiarrhythmic drugs may also be indicated.
Surgery is not common, but may be necessary in some congenital defects, such as persistent ductus arteriosus, in which a channel of the heart needs to be closed.
Regardless of the treatment chosen, the most important point is continuous veterinary follow-up, usually with reviews every three to six months to adjust doses and monitor the progress of the disease.
Day-to-day care
In addition to medical treatment, pet owners can adopt simple measures that make a big difference to their dog's well-being. Maintaining a balanced diet, with little salt and strict weight control, helps to avoid overloading the heart. Always follow veterinary recommendations.
Exercise should be light and moderate, always respecting the animal's limits, without forcing long walks or very agitated play.
A calm environment is also essential, as stress and excessive heat can aggravate symptoms.
It is important that the guardian learns to observe warning signs, such as rapid breathing at rest, persistent coughing or unusual tiredness, in order to inform the vet.
Finally, regular consultations are essential, as they allow you to adjust the treatment as it progresses and keep the disease under control for longer.
Frequently Asked Questions
Does a dog with a heart murmur feel pain?
The breath itself doesn't cause pain. It's just a sound.
What can cause discomfort is associated heart disease, especially when the dog has shortness of breath, tiredness or fluid retention. In other words: there is no "heartache", but there are symptoms that cause suffering if left unchecked.
Can a dog with a heart murmur die?
It depends on the cause. The best person to answer this is a veterinary specialist.
Innocent murmurs pose no risk. But pathological murmurs, linked to heart disease, can lead to serious complications if left untreated. This does not mean a death sentence: with early diagnosis and appropriate treatment, many dogs live for years with a good quality of life.
How long does a dog with a heart murmur live?
Life expectancy varies depending on the cause and severity. Some dogs live their whole lives with a mild murmur. Others, with more serious illnesses, may have a reduced lifespan. With treatment, many dogs live many more quality years.
The key is to diagnose early, treat correctly and always follow up with the vet.
How often should I take my dog to the vet with a murmur?
Ideally, dogs diagnosed with a murmur should have regular check-ups. In most cases, a check-up every three to six months is recommended, but the frequency can vary depending on the severity and response to treatment.
The veterinary cardiologist will define the safest interval for each case.
Does a dog with a murmur need surgery?
In most cases, no. Most dogs are only treated with medication and monitoring. Surgery may be indicated for some congenital diseases, such as persistent ductus arteriosus, but it is not common for acquired murmurs in adult or elderly dogs.
