Congestive Heart Failure in Dogs
As an emergency specialist, I often see both dogs and cats presenting to the emergency room due to congestive heart failure (CHF). CHF can be caused from several different types of diseases, and ultimately results in failure of the heart to pump blood throughout the body effectively. When pump failure occurs, it results in blood backing up into the lungs and fluid accumulation in the body. Fluid most commonly accumulates in three locations:
- Directly in the lungs (i.e., pulmonary edema)
- In the space surrounding the lungs (i.e., pleural effusion)
- In the abdomen (i.e., ascites)
Causes of congestive heart failure in dogs
There are several causes for congestive heart failure in dogs. Some causes may be congenital or inherited (where the dog was born with the heart defect), while some causes can be prevented.
Congenital defects include:
- Subaortic stenosis (SAS)
- Tetralogy of Fallot
- Ventricular septal defects (VSD)
- Persistent ductus arteriosis (PDA)
As these defects are inherited, dogs diagnosed with these problems should be spayed or neutered to prevent further spread of this defect.
Sometimes, inherited heart disease may not show up for several years or late in life. One particular type includes chronic valvular heart disease (CVHD), which results in leaky heart valves. CVHD is more commonly seen in Cavalier King Charles Spaniels, miniature poodles, and smaller breeds of dogs. With this type of heart disease, veterinarians often hear a loud heart murmur with a stethoscope (meaning that the blood flow through the heart sounds abnormal).
If your dog is diagnosed with a heart murmur, consultation with a cardiologist for an ultrasound of the heart (i.e., echocardiogram), chest x-rays, and heart monitoring (i.e., electrocardiogram) is generally recommended.
In larger dogs, CHF is typically due to dilated cardiomyopathy (DCM), where the heart muscle becomes to dilated and weak. This is more commonly seen in Doberman pinschers, Irish wolfhounds, and giant breed dogs. With DCM, a heart murmur may not always be detected with a stethoscope.
CHF may be seen due to abnormal heart arrhythmias. This is most commonly seen in Boxers (right arrhythmiogenic cardiomyopathy).
Lastly, some types of heart disease are potentially preventable, including heartworm infection. (Learn more about heartworm prevention with Beware the Bug.)
Symptoms of congestive heart failure in dogs
Clinical signs of CHF include:
- Constant panting
- Coughing, especially at night
- Exercise intolerance (e.g., getting tired easily on a walk)
- An increased respiratory rate
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Justine has more than 18 years of experience in the veterinary industry and is a board-certified emergency critical care veterinary specialist and toxicologist as well as the CEO and founder of Vetgirl. She is also a founding member of IDEXX’s Pet Health Network team.