The average lifespan of our companion animals has increased significantly thanks to the care we provide them and advances in veterinary medicine. However, with the increase in life expectancy, we will have to learn to live with pathologies that usually appear in geriatric animals.
Whether our dog has been diagnosed with a heart problem or if we have just added a canine member to the family, we want to be prepared to detect an irregularity as soon as possible. For this reason, our site offers you the following article on heart murmurs in dogs, in which we will detail the symptoms and treatment to clarify what the word refers to murmur and what we can expect after its diagnosis.
What is a heart murmur?
When we speak of a murmur, we refer to an abnormal sound detected on cardiac auscultation If we understand the heart and the great vessels that enter and they come out of it like a system of pipes, the murmur refers to the strange noise that is generated when the conduction of blood, through some of those pipes and stopcocks, encounters some difficulty.
The veins and arteries here would be pipes and the heart valves the stopcocks. Thus, if any of these pipes is obstructed (for example, if there is a clot in them), or any of the valves do not open or close properly, we will detect a non-physiological sound that is generally called a "blow". Therefore, when they tell us that our dog has a murmur, they are not making a diagnosis, they explain to us that something is happening in the normal conduction of blood, some alteration that can be due to multiple causes and several studies must be carried out to know what it is and what the treatment is.
Causes of a dog's heart murmur
We can find different types of heart murmur in dogs depending on their severity. The most serious are caused by a heart disease or failure in dogs, such as chronic valvular disease, congenital heart disease or bacterial endocarditis. An anemia could also cause a murmur. There are other mild murmurs, called "innocent" murmurs, which do not imply the existence of a disease and result from a degree that can be considered normal turbulence in the passage of blood through the heart.
Since it is impossible to cover all the possible causes of murmurs in dogs without writing a cardiology treatise, we will focus on the type of murmurs most commonly detected in the veterinary clinic, almost always during previous routine examinations to annual vaccinations.
Chronic valvular endocardiosis (CVD)
The literal translation of these three words means chronic degeneration of the heart valves (mitral, tricuspid, aortic and pulmonary). These valves are made up of several components and degeneration can affect all of them or a specific one in a special way. For example, the leaflets, the part that could be described as the valve gate, can be affected by the formation of myxomas, cauliflower-like nodules that prevent them from opening normally.
The valve sits on an annulus fibrosus. We could say that it is the door frame, which can also degenerate, but there are many other components that can suffer the same fate, although for different reasons. For example, the papillary muscles, which attach to the rim of the valves via the chordae tendineae, contract and relax to open and close these valves. When valves cannot close properly, it is called " failure". The blood projected towards another chamber of the heart experiences a reflux when the gate through which it comes out does not close correctly and that is what is detected with the stethoscope. In the case of EVC, that is precisely what happens. All the components of the valves, or some in particular, are not capable of fulfilling their mission, preventing hermetic closure of the valve after the blood is ejected through it.
Breeds predisposed to CVD
There are a number of breeds of dogs predisposed to suffering from chronic valvular endocardiosis of any of the valves (perhaps the most common is the Mitral), but that does not mean that is exclusive to them, but the proportion of patients of these affected races is greater than in any other. Some of these breeds are:
- Shih Tzu
- M altese
- Chihuahua
- Yorkshire terrier
- Poodle
- King Charles cavalier
The average age of presentation is 7-8 years, except in the King Charles cavalier, which can be diagnosed from 5 years of age with relative frequency.
There has been much speculation about the reason for this higher incidence in these breeds and it is believed that discolagenosis, a failure in the correct synthesis of collagen of genetic origin, may be behind it. The collagen matrix is essential throughout the valve structure and these breeds are predisposed to severe periodontal disease and knee ligament disorders. These alterations have collagen as a common denominator.
In general, if a murmur is detected in a review of a puppy over 7 years of age, of small size (less than 10 kg), mestizo or of any of these mentioned breeds, it is can issue a provisional diagnosis of chronic valvular endocardiosis until appropriate tests say otherwiseIt is not something frequent in cardiac pathologies, and many other factors must be taken into account and some tests must be carried out to corroborate it.
In this video we talk about other heart diseases that also present as a symptom the heart murmur of the affected dog:
Causes of heart murmur in puppies
When a heart murmur is detected in younger dogs it is usually due to a congenital heart disease In these cases there are various situations, depending on whether the heart defect is severe, moderate or mild. In serious problems, puppies usually die before reaching their first year of life.
When the defect is moderate, the dog lives but with symptoms such as exercise intolerance, fainting or rickets. On the other hand, puppies with mild affections are usually asymptomatic and the disease can be detected precisely when the veterinarian perceives a murmur in a routine examination.
There are congenital diseases that produce malformations in the valves or their narrowing, incorrect communications between the different chambers of the heart, persistence of conduits that should have been closed at birth or Tetralogy of Fallot, a pathology in which give four cardiac abnormalities. The management and prognosis of the affected puppy will depend on the cause, which the veterinarian must determine after tests such as those already mentioned.
How do you know if a dog has a heart murmur?
The murmur in the heart of dogs is in itself a symptom that there is an alteration at the cardiac level. With a problem of this type, it is normal for us to notice that our dog has a murmur and coughs a lot, since coughing is a very common symptom in dogs suffering from a murmur. This is more frequent at night or after physical activity.
Depending on the causative disease, which the veterinarian must identify, we can detect other symptoms of heart murmur in dogs:
- Lethargy
- Exercise intolerance
- Fainting
- Slimming
- Breathing changes
- Fever
- Joint inflammations
- Limp
- Behavior disturbances
- Seizures
CVD Symptoms
Since CVD is one of the most common causes of heart murmurs in dogs, let's take a closer look at what clinical signs it can produce. It is very common for it to be asymptomatic for months or years due to the compensatory capacity of the heart. The patient is then said to have a "compensated heart murmur": it is known that there is an anomaly, it is auscultated, but the patient shows normal symptoms and leads the same life as before.
During its annual review, before the vaccine or for any circumstance that leads us to the veterinary center, it is detected. However, it may be that after a while without realizing that there are problems, or after stable months, the pathology becomes unbalanced and symptoms begin to appear:
- Intense panting, it seems that our dog "laughs" when performing the same exercise as before.
- Exercise reluctance: refuses to climb stairs or lies down before finishing the daily walk.
- Cough, especially when lying down.
- Gagging and vomiting white foam.
- We can feel a strange turbulence in his chest, nothing resembling a normal heartbeat, by picking him up when the murmur reaches a significant pitch.
Do all CVDs decompensate?
Obviously after years in this situation the most common is a growth for the worse, but many dogs can live a perfectly normal life and long with this pathology with appropriate care. Our dog may die of natural causes before the decompensation of this type of valvular insufficiency occurs or due to any other unrelated disease.
The decompensation is usually progressive, not acute, so being observant and alert, we can detect it. However, a small percentage of cases can suffer an acute and fatal aggravation, if the chordae tendineae are torn, for example, something that happens in very few cases.
Diagnosis of heart murmur in dogs
As we have already mentioned, the veterinarian will detect the heart murmur through auscultation Once detected, to know exactly the type of murmur and, therefore, the cause that originates it, will carry out a deeper study. To do this, our veterinarian will propose a series of tests, such as plates and heart ultrasound (echocardiography) where the degree of valve injury can be ascertained and, in the event of plaques, the size of the heart, and possible lung involvement. Complete blood work is also necessary.
When the heart is unable to fulfill its mission, the first affected are the lungs, suffering from waterlogging known as pulmonary edema of cardiogenic origin, and that supposes an urgency. In this case, our dog shows symptoms of severe dyspnea, literally drowning.
What to do if my dog has a heart murmur?
The treatment for heart murmur in dogs will depend on the cause that causes it, so it is essential follow the specialist's instructionsin order to find it. As an example, and since this is the most common cause, we will see what the treatment of CVD consists of:
Treatment of chronic valvular endocardiosis
Some vets choose not to treat in the first instance due to the heart's ability to control the situation, as long as our dog is perfectly normal. Others, however, advocate prevention, providing the heart with a series of relief measures. It is not a treatment in itself, since it is not possible to reverse a valvular degeneration, but it is a support so that the heart can continue working at full capacity for as long as possible. Some of these support measures are:
- Drugs that inhibit angiotensin-converting enzyme: In other words, they are drugs that cause blood pressure to be lowered, which that in humans we know as "drugs for tension". The most used is benzepril once a day, for life, and can be combined later with other drugs. If the heart encounters less resistance in the vessels when ejecting blood, its performance will be better, and for this reason the use of this drug is recommended from early stages.
- Diuretics: Spironolactone, for example, is a potassium-sparing diuretic drug (others eliminate it in its quest, causing the long problems). Although it is a diuretic, in this disease it is used for another function that is more complicated, since no drug has only one function exclusively (just look at the famous Aspirin). It can be said that it further reduces tension and prevents fluid retention, giving less load to the heart.
- Positive inotropic drugs: Increase the force of contraction of the heart. It usually occurs in the final stages, combined with one of the above, to increase an already weakened strength of the heart muscle. Ex: pimobendan.
- Specific diets: From a certain stage, almost never in the initial stages, feeding with feed formulated for heart patients may be beneficial. They base their formulation on high levels of omega 3 fatty acids, great protectors of heart function and with a low s alt content. However, too early administration does not benefit the patient, so it is inadvisable to start supplying it to our dog on our own. There are also oils in the form of an independent nutritional supplement, with a high content of omega 3, which could be used in both initial and final stages.
Care for a dog with a heart murmur
Additionally, we can help our dog with chronic valvular endocardiosis, or other heart disease, with a series of he althy habits, in what that refers to feeding and caring for him:
- Maintain optimal weight, according to his age and race
- Short walks with regular breaks, preferably on level ground.
- Remove treats that are too s alty or fatty foods that we may be giving regularly (for example, when our dog "eats breakfast, lunch and dinner" with us).
- Use harness and not collar. The trachea can be displaced when the heart is enlarged by valvular insufficiency, and a harness does not compress the neck area.
- Reviews every 6 months or every year, according to the guidelines indicated by our veterinarian.
How long can a dog live with a heart murmur?
With proper treatment and care, a dog with a heart murmur can live as long as a dog without it. Of course, there are exceptions, since the cause of the murmur comes into play here. If we talk about CVD, as we have already mentioned, does not have to affect the life expectancy of the animal. In fact, in most cases patients do not die from this pathology.
Because of all the above, it is essential to go to a veterinary center if any anomaly is detected, such as the symptoms described above, since the prognosis depends on the speed of diagnosis.
