THERESA W. FOSSUM, DVM, MS, PHD, DIPLOMATE ACVS
MATTHEW W. MILLER, DVM, MS, DIPLOMATE ACVIM (CARDIOLOGY)
If your veterinarian says that your dog has congestive heart failure (CHF), you probably have a lot of questions. What does congestive heart failure mean? How long will my dog live? What can I do to help reduce his/her symptoms?
What is Congestive Heart Failure (CHF)?
First, heart failure does not mean that the heart has stopped pumping blood. It means that the heart is no longer pumping blood in a manner that meets the needs of the body. In essence, the heart contractions become weak and it no longer pumps blood effectively. Recall that the heart has 4 chambers; 2 are the atria which receive blood from the body (right atrium) or from the lungs (left atrium). The other two chambers are the ventricles which receive blood from the atria and pump it either to the lungs where it is oxygenated (right ventricle) or pump the oxygenated blood that comes from the lungs via the left atrium to the body (left ventricle). Congestive heart failure (CHF) occurs when the ventricles no longer pump enough blood to the body such that fluid accumulates in the lungs (pulmonary edema), abdomen (ascites), and other parts of the body.
What are the signs of CHF?
Your dog may have heart disease but will likely not show many signs until they develop CHF. Then, you may notice that they are more fatigued than normal, they may not want to exercise, they may develop a cough because of the fluid in their lungs, and they may breathe more rapidly. When fluid builds up in the lungs, a condition known as pulmonary edema, they will often have difficulty breathing. As the fluid builds up, your dog may have a reduced appetite and they may have trouble sleeping.
What causes CHF in dogs?
The most common cause of CHF in dogs is a condition known as mitral valve disease. In most cases the mitral valve, which is the valve between the left atrium and the left ventricle degenerates and does not properly close, which allows blood to flow in the wrong direction. Instead of all of the blood being pumped to the aorta and the body, some blood flows backwards through the mitral valve into the left atrium. This causes the heart to distend and the muscle to weaken even more over time.
How is CHF diagnosed?
Your veterinarian will listen to your dog’s heart to see if they can hear a murmur. They will likely also take chest X-rays to determine the size of the heart and to see if there is fluid in the lungs. They may refer you to a specialist to have an echocardiogram done. An echocardiogram can help determine the exact lesion in the heart and provide information on its severity. For example, the echocardiogram may show that the mitral valve leaflets are not working properly or that the heart muscle contractions are weak. They will also check to see if other causes of heart failure are present such primary or secondary heart muscle dysfunction, pulmonary hypertension (high blood pressure in the vessels in the lungs) or diseases that involve the sac (pericardium) that surrounds the heart.
How is CHF treated?
The treatment depends on the particular diagnosis. Symptomatic treatment may include providing oxygen, monitoring the heart for arrhythmias, monitoring blood pressure, removal of fluid from the chest or abdomen, use of diuretics (e.g., furosemide, spironolactone) to remove fluid from the lungs. drugs to improve the contractions of the heart (e.g., pimobendan) and an angiotensin-converting enzyme (ACE) inhibitor (enalapril, benazepril) which dilates the blood vessels to improve blood flow and thus lessen the work that the heart has to do to pump blood to the body. Many of these dogs are older and have other issues such as kidney disease or mobility issues and they are often on non-steroidal anti-inflammatory drugs (NSAIDS – caprofen, grapiprant). NSAIDS may cause kidney, digestive or liver problems in dogs so increasingly veterinarians and pet owners are supplementing, or in some cases even replacing, these drugs with more natural compounds such as CBD or hemp extract.
How long will my dog live?
If your dog has mitral valve disease there are new surgical techniques that are not widely available in the US, including repair of the valve. This surgery requires a heart-lung machine and is expensive but may result in long-term survival (years). In addition to extending their lives, dogs undergoing this surgery are often taken off of some or all other heart medications due to improvement in their heart function.