Congestive Heart Failure

What is congestive heart failure?

Congestive heart failure is a slow but progressive disease. It is most commonly seen in dogs and has two main causes.

  • dilated cardiomyopathy – occurs in middle-aged and older large breed dogs such as Dobermans, Boxers, and Great Danes
  • mitral valve insufficiency – usually observed in older, small breed dogs

What are the symptoms?

The signs of congestive heart failure can be hard to spot initially. Early on, the body is able to compensate for the reduced heart function by increasing the resistance of peripheral blood vessels and increasing heart rate. Blood pressure remains in the normal range as a result. The body also begins to retain sodium and water. The purpose of these adaptations is to keep the pet’s circulation in the normal range by increasing pressure. The high pressures eventually lead to the development of excess fluid in the tissues or body cavities.

  • Right-sided heart failure – causes the development of excess fluid in the abdomen while
  • left-sided heart failure – causes ‘pulmonary edema’ or fluid in the lung tissue.

Signs of left-sided congestive heart failure are related to the respiratory tract. Sufferers will experience coughing and shortness of breath. Signs of right-sided heart failure include swelling of the abdomen, legs, and other areas of the body due to excess fluid.


Treatments attempt to decrease the detrimental action by the pet’s own body, promote tissue perfusion, decrease excess fluid in body cavities and tissues, and stabilize the heart rate and rhythm.

Enzyme inhibitors

Drugs called ‘vasodilators’ are used to block the increase in peripheral resistance in the blood vessels by dilating these vessels. The most commonly used vasodilator in veterinary medicine is the angiotensin-converting enzyme inhibitor, or ace inhibitor, enalapril. Enalapril has been shown to decrease pulmonary edema, lower heart rates of sufferers.


The removal of excessive fluid in the lungs and abdomen is usually achieved through the use of diuretics. The most commonly used diuretic is furosemide, which causes the loss of sodium, potassium, and chloride, and subsequently excess fluid in the urine. Side effects such as electrolyte imbalance and dehydration can occur with excessive amounts of diuretics.

Dietary therapy

Dietary therapy is an important part of heart failure therapy. The most common recommendation is a low sodium diet that helps to decrease fluid retention and therefore decrease excessive pressure in the blood vessels. Other drugs such as l-carnitine, fish oil, and coenzyme q10, may have some beneficial effects in some dogs with heart failure. Any treatment options must be determined by a veterinary professional.

If you have concerns about the management of your pet’s diagnosed congestive l heart failure or are worried about symptoms in your pet, contact your local Greencross Vets.

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