Dilated cardiomyopathy, or DCM, is the second-most-common type of heart disease on dogs.
It is more common in large breeds such as Dobermans, Great Danes, Labradors and Golden Retrievers.
DCM causes the heart muscle to weaken, making it stretch and become floppy, so it cannot pump blood efficiently. Dogs can often live with the problem for months, or years, with no obvious signs of illness. This is the silent phase.
Eventually, the body can no longer compensate for the heart’s inefficiency and congestive heart failure develops. This is the overt phase. Signs include coughing, weakness, breathlessness, harder breathing, weight loss, poor appetite and even collapse. If you notice any of these signs, you should take your dog to the vet, who will do further tests to diagnose the problem.
It is more difficult to diagnose DCM during the silent phase, but early diagnosis and early treatment can significantly prolong your dog’s life. There is now a screening programme to pick up dogs with early DCM. Dogs of the susceptible breeds who are over three years old can be screened.
Screening begins with a blood test to measure levels of a substance called Pro-BNP. If your dog has a normal pro-BNP level, he does not require any treatment. However, it is recommended that this blood test is repeated once a year as your dog is still at risk of developing the disease.
It is also useful for you to monitor your dog’s breathing rate at home. When he is resting, count the number of breaths he takes in one minute by watching his chest move up and down. You will soon learn what is normal for your dog. A normal respiratory rate for a large-breed dog should be less than 40 breaths per minute. There are free apps available to help you measure and record your dog’s breathing rate. If you notice an increase in his breathing rate, you should contact your vet.
If your dog has a higher-than-normal level of Pro-BNP, your vet will likely recommend an ultrasound examination of your dog’s heart. The vet can measure the size of the chambers in the heart. If DCM is diagnosed on ultrasound, your vet will discuss starting your dog on tablets to slow the progression of the condition.