Not every dog with a heart murmur is in heart failure. Some dogs have no outward signs for years, while others develop changes that need prompt examination. The most useful thing owners can do is notice whether breathing, exercise tolerance and general behavior are different from the dog’s normal routine.
Emergency signs come first
If your dog is struggling to breathe at rest, cannot get comfortable, collapses or has blue or gray gums, seek emergency care immediately. Do not wait for a virtual consultation, an over-the-counter cough medicine or the next scheduled cardiac appointment. Respiratory distress can have cardiac or noncardiac causes, and both need hands-on assessment.
Changes to call about promptly
New fainting episodes, marked fatigue, a worsening cough, a larger abdomen, declining appetite or a persistent increase in breathing while asleep deserve a veterinary call. A cough alone cannot prove that the heart is causing it. Respiratory disease and airway collapse are also possibilities, even in dogs with heart murmurs.
What happens during assessment
A veterinarian may listen to heart and lungs, check blood pressure and consider chest radiographs, echocardiography, ECG or laboratory tests. ACVIM heart-valve guidelines describe different treatment approaches according to the stage of disease; owners should not select prescription drugs from a list of symptoms.
Make ongoing care safer
Ask your veterinary team whether and how to track resting breathing rate, and keep a list of medicines and recent doses. Bring recordings of cough or fainting if obtained safely. More about changes after treatment and daily monitoring is available in the related guides.
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.