Interesting Facts About the Dog’s Heart

Heart disease in dogs is not uncommon and is best diagnosed before the first symptoms appear.

The heart plays a central role in supplying the entire body. It ensures that blood rich in oxygen and nutrients is pumped through the vessels to all organs and that metabolic waste products and carbon dioxide are removed again. If the heart is diseased, sooner or later it will no longer be able to perform this work. The consequences usually come on gradually. Dogs with heart disease are often less willing to perform, have a cough or breathe faster than before. Sudden fainting spells can sometimes be observed, and in rare cases and advanced stages even shortness of breath. Blue mucous membranes or a stomach swelled with fluid can also indicate an insufficiently working heart.

It is important, however, that these symptoms can also occur in other diseases, i.e. they are not specific. Only a veterinarian can diagnose whether a dog has a heart condition and, if so, what it is after a thorough examination.

A disease of the left heart valve, the so-called mitral endocarditis, is particularly common in older animals of small dog breeds. In a healthy dog, the heart valves prevent blood from flowing in the wrong direction within the heart. If the left valve no longer closes properly, the blood flows back into the left atrium, which can then extend into the lungs.

Larger breeds are more likely to suffer from heart muscle weakness, dilated cardiomyopathy, or DCM for short. In this disease, the heart muscle is too weak to pump enough blood through the circulatory system. The body tries to compensate for this by increasing the blood volume, among other things. However, because the heart does not have the strength to pump larger amounts, the ventricles fill with more and more blood. This stretches the walls of the chambers. They get thinner and thinner and eventually wear out. DCM can also affect young dogs.

Dogs can also be born with a heart defect, even if it’s not immediately obvious. It is therefore important to routinely listen to puppies to be able to intervene as early as possible. Because once the dog shows symptoms, it can already be too late for an intervention.

Heart disease is usually associated with a loss of function. At the beginning of an illness, the dog usually does not notice anything at all, since the heart can initially successfully compensate for its reduced performance. Unfortunately not in the long term, because over time these compensatory mechanisms put even more strain on the already ailing heart. Sooner or later they, therefore, lead to further deterioration and visible symptoms.

To stop this vicious circle, attempts are made to relieve and strengthen the heart with the help of medication. In this way, the course of the disease should be slowed down and the heart’s still-existing performance should be preserved. However, changes that have already occurred in the heart valves or the heart muscle tissue themselves cannot be repaired even with medication. In this sense, a cure is not possible. But with the right treatment and regular check-ups, dogs with heart disease can often lead a carefree life.

The oxygen-rich blood from the lungs arrives in the left atrium and is pumped from the left ventricle into the systemic circulation. If the heart’s function is restricted on this side, blood remains in the heart. It builds up first in the left atrium and finally back into the blood vessels of the lungs. As a result, the increased pressure forces fluid out of the vessels into the tissue and alveoli. The vernacular speaks of “water in the lungs”. The dog tries to get rid of the liquid by coughing. As the process progresses, severe shortness of breath occurs. A cough can also be triggered when the left atrium enlarges due to the accumulated blood and presses on the airways of the lungs, the bronchi.

A heart-related cough is therefore usually associated with a weakness in the left heart, which can have different causes. For example, a defective heart valve can be behind it, or a pumping weakness of the left ventricle.

Listening to the heart with a stethoscope is part of every general examination and at the same time a fundamental part of the special heart examination. The veterinarian pays attention to the frequency, rhythm, and intensity of the heart sounds. He assesses whether the heart sounds are separated from each other and whether so-called heart murmurs can also be heard in addition to the heart sounds. If the veterinarian detects a heart murmur during a routine check-up, for example at the vaccination appointment, he must get to the bottom of the matter. Because behind it can – even in animals that show no symptoms! – hide the early stage of heart disease. Experienced veterinarians can already determine a lot by listening. But some things cannot be checked in this way, or cannot be checked clearly.

X-rays can be used to assess the size and shape of the heart and its position in the chest. Fluid accumulations in the pericardial sac or the lungs can also be detected in this way.

The ultrasound examination is now part of the standard of a more in-depth heart examination. With their help, one can assess the heart valves, the thickness of the heart walls, and the filling status of the two heart chambers and atria. The heart can be measured with the “sound”. The inside diameter is often determined. With the so-called color Doppler ultrasound, you can even observe the blood flow and currents during heart work. For example, in the case of mitral valve insufficiency, the backflow into the left atrium becomes visible.

Incidentally, cardiac arrhythmias can best be assessed with an electrocardiogram (ECG). If they only occur occasionally, it may be advisable to create a 24-hour ECG (Holter ECG).

The so-called heart sounds occur during the normal activity of the heart. Everything that can be heard when listening to the heart’s activity is referred to as a heart murmur. Heart murmurs are not always abnormal, but in most cases, they are due to a diseased heart. Therefore, such a finding must be clarified – even if the dog appears completely healthy. He may be in the early phase of heart disease, in which the dog is not visible from the outside, but the veterinarian can already detect the first changes in the heart. With the help of special examination methods – such as ultrasound – he can best assess whether it is sufficient to continue to observe the dog for the time being, or whether treatment must already be started. The vet may also refer the owner to a heart specialist for this. The latest studies show that the lifespan of dogs could be significantly extended if, based on certain heart findings, drug therapy was started before the first symptoms appeared. This could be shown above all for the so-called calcium sensitizers. These are active ingredients that on the one hand increase the strength of the heart, but on the other hand, also relieve the heart by expanding the vessels. This could be shown above all for the so-called calcium sensitizers. These are active ingredients that on the one hand increase the strength of the heart, but on the other hand, also relieve the heart by expanding the vessels. This could be shown above all for the so-called calcium sensitizers. These are active ingredients that on the one hand increase the strength of the heart, but on the other hand, also relieve the heart by expanding the vessels.

The heart and kidneys are closely related. Their functions influence each other, which becomes particularly clear when one of the two organs becomes diseased. In a dog with heart disease, the functionality of the kidneys should therefore always be kept in mind. On the other hand, certain tasks of the kidneys can also be used therapeutically to relieve the heart. The means that are used here are so-called diuretics and ACE inhibitors.

Diuretics are draining drugs. They cause the kidneys to excrete more fluid in the urine. In this way, the body is deprived of unnecessary fluid that has accumulated in the lungs or body.

ACE inhibitors prevent blood vessels from narrowing severely. The body tries to compensate for the lack of cardiac output by constricting the blood vessels. In the long run, however, it puts even more strain on the heart. If the vessels are dilated by medication, the heart is relieved because it has to work against less resistance.

It is vital for a dog with heart disease that receives its medication regularly and at the exact dose. But, even if the dog gets better under the therapy, the heart is and will remain damaged. It should not be burdened unnecessarily. That doesn’t mean the dog can’t be active; however, he should move regularly, evenly, and by the severity of the disease. Extreme physical exertion should be avoided in any case.

Being overweight puts a lot of strain on the heart. Dogs with too many pounds should therefore reduce their weight. When feeding, it is also important to ensure that the salt content in the feed is low. Table salt binds water in the body, which in turn increases the load on the heart.

Owners should observe their dog in everyday life, as they know him best. The veterinarian can also show the owner how to measure the resting respiratory rate. It serves as a simple and reliable control method: If the frequency increases, fluid may have collected in the lungs and a veterinarian should be informed immediately. Does a dog tire more quickly or cough more? These can also be warning signs. Regular check-ups at the vet are mandatory for heart patients!

In principle, every dog ​​can develop heart problems in the course of its life. There are no specific measures to prevent this. But a species-appropriate attitude with a healthy, balanced diet and sufficient exercise is in any case an important and good basis for a healthy dog ​​life.

Certain risk groups are particularly likely to develop heart disease. For certain valve diseases, these in particular older animals of small dog breeds. Heart muscle weakness (DCM) is mainly in larger dog breeds between the ages of one and a half and seven years. A special feature is the DCM of the Doberman and Boxer. It is insidious, since the animals appear completely healthy for a long time, although typical cardiac arrhythmias already occur, i.e. the heart muscle is already damaged. Sudden deaths are not uncommon and even dogs that survive this stage do not have a long life expectancy. However, if the disease is discovered and treated before the first symptoms appear, life can be significantly extended. The following applies to all heart diseases: the earlier the diagnosis, the better. It is therefore important for high-risk animals to have a heart check carried out by the vet regularly, preferably annually.

Frequently Asked Question

How does a dog’s heartbeat?

You will feel a faster heartbeat in puppies than in adult and older dogs. A normal heart rate for a puppy is between 100 and 120 beats per minute. About 90 to 100 beats per minute in an adult dog, and 70 to 80 beats per minute in an older dog.

How many heart valves does a dog have?

The heart has a total of four heart valves. Two of them are located between the two atria of the heart and the two chambers of the heart (ventricles).

How big is a dog’s heart?

We measured the heart, and the longitudinal axis and the transverse axis of the heart are converted to the length of the thoracic vertebrae according to certain specifications. Faust measured 13.2 vertebrae, normal is a value of 9-10.5, with breed-related variations.

Why does a dog’s heart enlarge?

Chronic valvular disease is the leading cause of heart failure in dogs. It mostly occurs in older dogs and smaller breeds like poodles and dachshunds. The heart valve is thickened and does not close completely with each heartbeat. This causes blood to flow back into the vessels and organs.

What causes cardiac arrest in dogs?

If your dog has consumed large amounts of caffeine, it can even go into a coma and suffer cardiac arrest. The first symptoms of caffeine intoxication appear after about 2 to 4 hours.

Why can’t dogs have heart attacks?

The risk of a heart attack in animals is also reduced by a – genetically determined – different lipid metabolism. As a result, the risk of developing atherosclerosis in animals is significantly lower, but not zero.

Why does a dog suddenly die?

There are many reasons your pet can die suddenly. Through an inherited characteristic, due to an unknown disease, or as a result of an injury. One of the most common causes is heart disease, particularly cardiac arrhythmia, blood clots, and myocardial disease.

What does it mean when dogs pant?

Dogs can hardly sweat and need to pant to avoid overheating. After exertion or in great heat, it is also important for the dog to pant heavily. If the dog pants during or after emotional excitement, this can also be classified as normal behavior.