Clinical history

Signalment is an important consideration when diagnosing congestive heart failure (CHF) in dogs. In particular, it is important to assess the following factors:

• Age: Middle-aged and older dogs are more susceptible to heart disease and heart failure. Dilated cardiomyopathy (DCM) primarily affects middle-aged dogs, whereas atrioventricular valvular insufficiency (AVVI) most commonly appears in older dogs.
• Breed: Small dogs are more susceptible to AVVI, whereas large and giant breeds are more susceptible to DCM. Also, pay attention to at-risk breeds for each disease.
  • Click here for AVVI-susceptible breeds.
  • Click here for DCM-susceptible breeds.

History: To obtain the most complete clinical history about a dog, ask the pet owner specific questions about the following factors:

• Changes in attitude, behavior, and activity level: Exercise intolerance, depression, and fatigue are all signs associated with CHF.
• Changes in breathing: Labored breathing or an increased resting respiratory rate can indicate CHF.
• Changes in appetite and weight: These factors can also signal a heart problem.
• Coughing: Include evaluation of onset and type of cough. Dogs with pulmonary edema have acute cough. Dogs with chronic heart disease have mild, intermittent cough.
• Sleeping habits: Restlessness at night is commonly associated with CHF.
• Previous evidence of heart disease: Heart murmurs or radiographic changes, such as an enlarged heart, can indicate heart disease.
• Therapy: Consider any preceding treatments, including compliance with heartworm prevention programs.