A heart murmur in a puppy can be harmless in some circumstances, but it can also indicate a congenital structural defect. Heart disease in a young dog is not necessarily the same condition seen in older small-breed dogs, and treatment must follow the actual diagnosis rather than an age-based medicine list.
Why puppies may have a heart murmur
Some young dogs are born with defects affecting valves, abnormal connections or blood flow through the heart. A veterinarian may recommend a careful examination, chest radiographs or an echocardiogram with a veterinary cardiologist to determine whether an abnormality is present. The loudness of a murmur does not always reveal its severity.
Signs owners should mention
Slow growth, fatigue during play, coughing, fainting, fast breathing at rest or trouble keeping up with littermates deserve assessment. Some affected dogs have no obvious symptoms. A dog with difficulty breathing, gray or blue gums, severe weakness or collapse needs emergency care immediately.
Treatment depends on the defect
Some structural conditions may be treated with catheter-based or surgical procedures, while others require ongoing medication or monitoring. Giving a medication used for an older dog with valve disease may be inappropriate for a young patient with a different heart disorder. A specialist can help explain the prognosis and follow-up plan.
Questions for the next appointment
Ask what condition is suspected, whether an echocardiogram is needed and what level of exercise is appropriate until the diagnosis is clear. For the difference between an incidental murmur and heart failure, see warning signs in dogs with heart disease.
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.