Goals of Treating HCM
The goals of treating hypertrophic cardiomyopathy (HCM) are to reduce any fluid build-up around the heart and lungs (pleural effusion and pulmonary edema), stabilize the dog’s heart rhythms, relieve the dog’s discomfort and restore a good quality of life.
A number of different pharmaceuticals are available to help manage hypertrophic cardiomyopathy. Drugs known as beta blockers, ACE inhibitors, vasodilators and calcium channel blockers can help to reduce or stabilize a dog’s heart rate and rhythm and prolong ventricular filling time. Other drugs, including diuretics, are available to help if signs of congestive heart failure are present. If the dog has an abnormal build-up of fluid in its chest, a procedure called thoracocentesis can be performed to remove some of that fluid and help normalize breathing. This involves inserting a sterile needle through the thoracic (chest) wall and drawing off the fluid through an attached syringe. Oxygen therapy, either in an oxygen cage or through a mask, may be appropriate in some cases. Intravenous fluids can be administered in the veterinary hospital if necessary to correct fluid or electrolyte imbalances.
Dogs with HCM should not be placed under undue stress. Their diet should be low in salt. Some experts recommend giving an anticoagulant drug – such as one human baby aspirin every 3 days - to try to prevent the development of arterial thromboembolisms. However, the efficacy of this protocol has not been proven in dogs, and owners should consult with their veterinarian before starting any type of drug therapy for their pet.
The prognosis for dogs with HCM is highly variable. In mild, nonprogressive cases with no outward clinical signs of disease, the outlook is fair to good. However, once the left ventricular wall becomes severely thickened, with accompanying left atrial enlargement, pleural effusion and pulmonary edema, the prognosis is guarded to poor. If the dog develops thromboembolisms, the chance of long-term survival is grave.