A dog who suddenly begins breathing with effort may be experiencing congestive heart failure, but other emergencies—including pneumonia, heat illness, airway obstruction or fluid around the lungs—can look similar. The right response is rapid in-person veterinary assessment rather than trying to decide the cause at home.
What heart failure means
Heart failure occurs when heart disease causes circulation or fluid-management problems significant enough to create clinical signs. In left-sided congestive failure, fluid may accumulate in the lungs and make breathing difficult. Dogs with pre-existing murmurs may develop heart failure, although not every murmur means failure is present.
Emergency signs
Go to an emergency veterinarian for labored breathing, an inability to lie down comfortably, blue or gray gums, collapse or severe weakness. Keep the dog calm and avoid exercise while arranging transport. Do not attempt to force pills, food or water into a breathless animal, and do not administer leftover diuretics without instructions.
What the clinic may do
Emergency personnel may supply oxygen and use physical examination and imaging to determine whether pulmonary edema or another problem is present. Treatment can require monitored diuretics or other interventions depending on the diagnosis. Stabilization is followed by a plan for ongoing cardiac monitoring and medication when appropriate.
Preventing avoidable delays
If a dog already has diagnosed heart disease, ask the treating clinic what breathing and activity changes to watch for and how to reach emergency care after hours. Learn about cardiac warning signs and long-term care.
Clinical source
ACVIM consensus guidelines for canine mitral valve disease (2019). These guidelines concern mitral valve disease, not every form of canine heart disease.
This article is educational. New breathing difficulty or collapse calls for emergency veterinary care; prescribed heart medication must be managed by the treating veterinarian.
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.