Congestive Heart Failure in Dogs and Cats
Heart failure occurs when the heart is unable to pump enough blood for the body’s vital organs to function properly. Heart failure is not a specific disease – instead, it is the result of underlying heart conditions that may be present due to an abnormality of the heart’s structure, ability to contract, or electrical activity.
Congestive heart failure, or CHF, occurs when fluid begins to build up within the lungs (pulmonary edema), in the chest cavity (pleural effusion), and/or in the abdomen (ascites) as a result of heart disease. This congestion causes major organs to function abnormally and/or swell with fluid. Degenerative valve disease in dogs and hypertrophic cardiomyopathy in cats commonly lead to CHF.
In general, heart failure results from any of the following:
- Leaky heart valves allowing blood to flow backwards though the heart, overloading the blood vessels in the lungs
- The reduced ability of the heart muscle to contract
- An obstruction to blood flow, such as a tumor in or near the heart
- Abnormal heart rhythm preventing the heart from effectively pumping blood
- Uncontrolled high blood pressure, increasing the workload of the heart
If your pet has an underlying heart disease that causes these issues, they may be at risk for heart failure. Heart disease is a collective term encompassing a wide range of conditions, which can be either congenital (present at birth) or acquired (developed over the pet’s lifetime). The following factors can increase the risk of a pet developing heart disease:
- Age – heart disease occurs more frequently in older pets.
- Breed – certain heart disorders are more common in particular breeds.
- In cats, a diet deficient in the amino acid taurine results in dilated cardiomyopathy.
- In dogs, the Food and Drug Administration has reported a potential association between grain-free diets with the development of dilated cardiomyopathy.
For information on common types of heart diseases in pets, visit Heart Disease in Dogs and Cats.
Signs of congestive heart failure in dogs and cats may include:
- Difficulty breathing
- Exercise intolerance
- Rapid breathing >40 breaths per minute
- Loss of appetite
- Distended abdomen
- Cold paws or ears due to lower body temperature (more common in cats)
If your pet already has an underlying heart condition, your veterinarian will check for clinical signs of heart failure. Congestive heart failure can be diagnosed with a chest x-ray to check for fluid in the lungs (pulmonary edema) and blood tests to check for hormone levels associated with heart disease.
The treatment of heart failure in pets depends on the underlying disorder. As congestive heart failure occurs due to the buildup of fluid in and around major organs, the congestive signs are treated with drugs that help to remove fluid. For pets with abnormal heart rates and rhythms, correction of the abnormality can resolve CHF. Medications that dilate blood vessels allow them to hold more fluid and decrease the workload of the heart. Medications can include:
- Diuretics – help to remove fluid that accumulates in dogs and cats with heart disease.
- Oxygen therapy – for pets with a pulmonary edema (fluid in the lungs) or pleural effusion (fluid around the lungs) that have difficulty breathing, supplemental oxygen is administered through an oxygen cage, mask, collar, or nose tube.
Other treatment options may include:
- Pimobendan – opens up the blood vessels that take blood away from the heart, effectively reducing work the heart does to pump blood. At the same time, it opens up the blood vessels returning blood to the heart, reducing pressure. It also increases the strength of the heart’s contraction.
- ACE inhibitors and vasodilators – used to treat heart failure by relaxing and enlarging blood vessels.
- Antiarrhythmic drugs and pacemaker implantations – correct the abnormal heart rate and rhythm, allowing the heart to effectively pump blood.
- Thoracentesis and abdominocentesis – these surgical procedures are performed on pets with fluid buildup around the lungs and/or abdomen. A needle is placed through the skin into the pet’s body to remove the excess fluid.
- Dietary changes – used to supply adequate calories, reduce inflammation, and supplement missing nutrients (such as taurine for cats with a taurine deficiency). Low-sodium diets may be recommended for pets with severe CHF.
An annual physical examination includes listening to the heart with a stethoscope. Identification of a heart murmur or an abnormal heart rhythm are signs of heart disease. These findings may lead to a referral to a board-certified veterinary cardiologist who can determine your pet’s risk for developing heart failure.
If your pet is diagnosed with heart disease, make a habit of counting and recording their breathing rate. One full breath equals one inhale plus one exhale. If you notice a trend in an increased breathing rate over the normal rate for a few days in a row, or a breathing rate greater than 40 breaths per minute, seek veterinary care immediately.