Of all the diseases and health problems that could affect your dog, there are few as scary-sounding as mitral valve disease. Although fairly uncommon in dogs, if left untreated, mitral valve disease can result in congestive heart failure, which is a fatal condition. When a heart valve fails in humans, a surgeon will usually intervene and replace the valve, but this isn’t a viable option for dogs. Problems with the mitral valve are often treated with drugs and lifestyle changes.
What causes mitral valve problems?
Your dog’s heart has four chambers, the upper atria and the lower ventricles. The heart is also divided into two halves, the left and the right. Each chamber has a one-way valve to prevent the blood from flowing backwards. The valve between the left chamber and atrium is called the mitral valve, and this can wear out and become leaky over time.The left side of the heart is responsible for pumping the oxygen-rich blood around the body, and so it has the thickest muscle to help with this task. When the valve leaks, this is known as mitral valve insufficiency and is most often detected as a heart murmur.
How common is mitral valve disease?
Around one in ten dogs will suffer from some form of heart disease in their lifetime, and mitral valve disease is more likely to affect small dogs than larger ones.
How is mitral valve disease diagnosed?
Your vet will start with a physical examination and take your pet’s history. They will usually ask if you have noticed any changes in your pet’s behaviour that have prompted a visit to the vet. They will also listen to the heart and lungs using a stethoscope. Other tests for might include chest x-rays, blood and urine tests, electrocardiograms and echocardiograms.
What signs should I look out for that my dog has mitral valve problems?
When blood backs up in the heart, it will slowly start to back up into the lungs and often cause small amounts of fluid to leak out the capillaries into the airways. This will cause your dog to gag or cough as if it is trying to clear its throat. Your dog may also have low stamina as a result of the fluid collecting in his lungs.
What treatment is available?
There are a number of drugs available to help treat the progression of mitral valve disease. Angiotensin Converting Enzyme inhibitors lower the blood pressure, which will help to relieve pressure on the heart. Diuretics stimulate the kidneys to remove excess water from the body and relieve pressure. Nitroglycerin may be used in an emergency to dilate the blood vessels, allowing more room for the blood and to prevent backflow. Beta-blockers may be used to slow down the heart, while vasodilators can be used as a long-term alternative to nitroglycerine to dilate the blood vessels. Digitalis is another drug that will slow the heart rate and strengthen the heart contractions.
Your dog will also be prescribed a low sodium diet to prevent excessive water retention. If your vet prescribes a specific diet, it's very important you follow this and don't allow your pet to eat human food.