Bonn. Heart disease is relatively common in dogs. One in ten dogs is affected. Some dog breeds, usually smaller ones, are affected more often than others and are considered to be at risk dog breeds. The risk of heart disease also increases with increasing age.
What is meant by heart failure?
Heart failure occurs when the heart is no longer able to pump enough blood into the circulatory system. As a result, the organism is inadequately supplied with blood and oxygen. The body reacts to this condition by narrowing the blood vessels. Heart failure is relatively common in dogs and can be inherited genetically or acquired later in life. The causes of acquired heart failure are predominantly a disease of the heart valves or the heart muscle.
This is how the cardiopulmonary circulation works
The blood is enriched with oxygen in the lungs. The oxygen-rich blood flows from the lungs into the left half of the heart, first into the atrium and then into the ventricle. From there it is pumped into the body with every beat of the heart and thus into the brain, muscles and other important organs. The used, oxygen-poor blood flows from the body back into the right half of the heart, first into the atrium and then into the main chamber. With every heartbeat, the oxygen-poor blood is pumped from the right side of the heart into the lungs, where it is enriched with oxygen and returned to the left heart. In this circuit, the heart valves take on the function of “valves”. They ensure that the blood can flow in the right direction. If the heart valves are pathologically changed – this is often due to degenerative remodeling processes in the connective tissue of the heart valves – they no longer close properly and the blood flow is disrupted. The process is also disrupted if the heart muscle is weakened and cannot pump enough blood into the circulation – blood congestion occurs in the heart, lungs or body, which can trigger coughing or shortness of breath.
What are the causes of heart failure?
Chronic valvular disease is the leading cause of heart failure in dogs. It occurs primarily in older dogs and smaller breeds such as Cavalier King Charles, Yorkshire Terriers, Poodles and Dachshunds. Male animals are affected one and a half to two times more often than females. Changes and thickening occur in the heart valves, which means they only close incompletely with each heartbeat. This causes blood to flow back into the vessels and organs. The so-called mitral valve is usually affected (mitral valve endocardiosis), less commonly the tricuspid valve. Both flaps can also be changed. If the valve disease has existed for a long time, the atrium and ventricle become enlarged. The disease usually progresses gradually.
Dilated cardiomyopathy is the second most common acquired heart disease in dogs. It occurs almost exclusively in younger to middle-aged larger dogs, such as the Doberman, Wolfhound or Great Dane. The heart muscle becomes thin and weak and can no longer provide its pumping performance. Male dogs are generally affected more often, more severely and earlier than female animals. The disease usually progresses quite quickly. Heart rhythm disturbances, so-called arrhythmias, can also occur, which in some cases lead to sudden cardiac death (second death) can lead. In some dogs, predominantly Dobermans, such arrhythmias can occur before the first clinical signs of heart disease become visible.
Of course, as with humans, other factors such as age and body weight also play a crucial role in dogs. With increasing years of life and every extra pound you lose, the risk of heart disease increases. It is all the more important to feed your dog a healthy diet, offer him enough exercise in the fresh air and take him to the veterinary practice regularly for a check-up. The earlier heart disease is detected, the better the dog can be helped to live as long as possible with a good quality of life.
What symptoms of heart failure can pet owners recognize?
Heart disease usually begins gradually, as at the beginning of the disease the heart can still compensate for the poorer performance by working more. The dog appears healthy. This phase is called the preclinical phase. Dogs with heart disease may appear tired and weak in the later stages. Maybe the food bowl is often left untouched or the dog has already lost weight? After just short walks, you may experience difficulty breathing, coughing or feeling tired. If the disease is advanced, these symptoms appear even at rest. In dramatic cases, this leads to collapse or fainting because the brain is no longer supplied with enough oxygen.
What options does the vet have to diagnose heart failure?
During a routine examination, your veterinarian can detect the first signs of heart failure. Listening to the heart and lungs is crucial. If the vet detects an abnormal heart murmur early on, this can be an important indication of valve disease, even though the dog does not yet show any symptoms of heart failure. A heart murmur occurs when blood swirls around the heart valves when they no longer close properly. This is often the first finding of heart disease. With the help of further examinations such as X-rays, cardiac ultrasound, blood tests for special cardiac parameters (biomarkers) or ECG, a clear diagnosis of the underlying heart disease is possible. Advanced heart failure shows an enlarged heart, an irregular heart rhythm, impaired kidney function or fluid accumulation in the lungs or other organs.
What treatment options are there for heart failure?
If there is suspicion, the pet owner can support the vet's therapy by carefully observing the dog. In particular, an increase in the resting breathing rate is a good indication of a worsening of the heart disease. The breathing rate of a resting dog should not exceed 30 breaths per minute. A breath is characterized by the rise and fall of the chest. Valuable support can be a breathing diary or the use of a digital application to determine and document the breathing rate.
Although there is no cure for heart failure, targeted and early drug treatment can enable the dog to live a longer and, above all, more carefree life. Basically, the aim is to relieve the heart of its work at an early stage by expanding the blood vessels and strengthening the heart muscle and thus improving the strength of the weakened heart. In this way, the resistance against which the heart has to pump is reduced. The sick heart has to exert less force and can supply the organism with oxygen more effectively. In the advanced course of the disease, the so-called clinical phase, diuretic medications are also used.
The treatment of heart failure in dogs consists of several components that are used depending on the severity. The veterinarian has a number of effective and well-tolerated medications available to ensure good therapy that is tailored to the respective clinical picture. Regular, daily and lifelong medication administration is crucial.
Recently, there has been a rethink in small animal medicine when it comes to treating dogs with heart disease. Waiting until the first clinical signs of heart disease appear is now a thing of the past. New scientific findings from long-term studies with several hundred dogs from different countries clearly show that drug treatment makes sense in the preclinical phase of the disease. The preclinical phase, in which the dogs still appear completely healthy but already have an enlarged heart muscle, can be significantly prolonged with the right heart medication. Heart-strengthening medications relieve the strain on the heart even in the preclinical phase. That's why regular checkups are so important.
Accompanying measures
- Movement: Adequate exercise is very important for a dog with heart disease, but it is important to ensure that the activities are regular and consistent and do not overwhelm the animal. It is therefore healthier for the patient to exercise for half an hour several times a day than for several hours once or twice a week. The uniformity of movement is also important. In addition to walks, swimming and slow running next to the bike are recommended, but playing with a ball is not so suitable.
- Nutrition: A healthy diet and normal weight can help maintain the quality of life of a dog with heart disease for years to come. Some nutrients and nutrient combinations have heart-friendly properties and have positive effects on health. Special food is therefore offered for dogs with heart disease. This is usually low in sodium. Other supplementary feeds contain highly concentrated omega-3 fatty acids. These are important essential fatty acids that the dog cannot produce itself, but which are very important for heart health. The vet can provide information about this.