What is dilated cardiomyopathy? (DCM)
A condition that causes the heart to become enlarged and with poor contractile strength. The valves and blood vessels are normally relatively normal, but the heart muscle becomes stretched, weak and floppy and fails to pump blood properly.
What kind of dog gets DCM?
The incidence of this disease is estimated at 0.5-1.1% of the canine population.
There is thought to be an inherited genetic component with some breeds being more prone to developing the disease. Doberman pinschers, boxers, Giant breeds (Scottish deerhound, Irish wolfhounds, Great Danes, St Bernards, Afghan hounds) and Cocker Spaniels are all over-represented.
Average age of onset is between 4-10 years old.
Males of some breeds are more often affected than the females.
What are the signs of DCM?
Some dogs do not show any symptoms at all. Others show respiratory signs of breathing fast or with difficulty, and coughing. Many dogs have weight loss, weakness, lack of appetite and lethargy. Some dogs have a bloated appearacne to their abdomen due to fluid build up, and fainting is not uncommon.
What is found when my vet does a physical examination?
Your vet will find physical signs characteristic of the underlying condition. If your dog is mildly affected then there may be little to find without diagnostic tests being used. If there is an associated arrhythmia (abnormal heart beat rhythm), then this can be heard, and there may be a discrepancy between the heard heart beat and the pulses that can be felt elsewhere in the body. Your dog may have crackles in its lungs, an audible heart murmur, be depressed and have weak pulses. They may have pale gums and have a slow refill time after being blanched by gentle pressure. There may be a large liver palpable.
WHen your vet does their physical examination, they will check all these things, even if you think they are “just stroking them” your vets hands will be feeling for and finding things you aren’t aware of.
What are the causes of DCM?
In many cases there is no known cause. These cases are called idiopathic.
Nutritional deficiencies of taurine and/or carnitine have been linked to cases in some breeds.
An underactive thyroid may cause reversible heart failure if treated promptly.
What are the diagnostic tests for DCM?
Your vet will probably advise taking some blood tests and will want to perform (or refer your dog for) an echocardiogram (ultrasound scan of the heart) and an electrocardiogram (documenting the electrical activity of the heart). The condition is best diagnosed by echocardiography. Xrays of the chest to get an overall picture of the size of the heart and condition of the lungs may also be useful and recommended.
The characteristic changes seen in this condition are an enlargement of all four chambers of the heart, together with thinning of their muscle walls.
What is the treatment for DCM?
Most dogs can be managed as outpatients.
Unless severely affected or advised otherwise by your vet, let your dog choose their own level of activity. Do not try to push them to do more than they want. This could be very dangerous.
Diet should have a mild sodium (salt) restriction. Severe restriction is not necessary due to the mainstays of drug therapies that are used.
Ensuring you, the owner, is fully aware of the potential signs associated with disease progression, and what the adverse effects of medication may be.
This is the mainstay of treatment options for DCM. Your vet will need to diagnose the problems your dog has associated with his DCM, and then prescribe appropriate treatments to address these problems. There is not a “DCM pill” and your dog will be on multiple drugs.
Your vet will discuss what treatment is right for your dog and monitor their response to treatment.
Examples of drugs that may be recommended include:
What monitoring should my dog with DCM receive?
Lots is probably the only true answer here. Follow up clinical examinations, xrays and ECGs are often needed.
If your dog is prescribed Digoxin then regular (and initially fairly frequent) blood samples to check the levels of the drug in their blood will be necessary.
What are the possible complications I should be prepared for?
Unfortunately sudden death may occur if the heart spontaneously enters an abnormal rhythm that is incompatible with life. There may also be complications associated with the life saving medications.
What is the prognosis associated with DCM?
Not good I’m afraid. It is a condition that is always fatal and can never be cured. Most dogs live for 6-24 months after the time of diagnosis, however Dobermans have a worse prognosis and often live less than 6 months after diagnosis. Dogs which are found to have certain abnormal heart rhythms are also found to live less time.
Questions? Email me.