Understanding Puppy Heart Murmurs and Congenital Heart Disease

In this episode of Pure Dog Talk’s “Veterinary Voice,” host Laura Reeves and Dr. Marty Greer explore the complexities of congenital heart disease in puppies, offering essential guidance for breeders on diagnosing, treating and navigating cardiac health in their litters.

The Importance of the First Vet Visit & Puppy Murmurs

Dr. Greer emphasizes the crucial need for a thorough veterinary exam before placing any puppies in their forever homes to protect the breeder’s reputation and ensure the puppy’s health. A heart murmur occurs when blood flows backward through the heart, creating turbulence. Veterinarians grade these murmurs on a scale from one to six, where a grade one is incredibly subtle and a grade six is loud enough to be felt through the chest wall without a stethoscope.

To ensure an accurate diagnosis, Dr. Greer advises that the puppy must have all four feet on the exam table in a completely quiet room. While some early, subtle murmurs resolve over time or are simply caused by typical puppy anemia, any persisting or loud murmur requires an echocardiogram.

The 5 Common Congenital Heart Defects in Puppies Dr. Greer details the most frequently diagnosed congenital heart defects:

• Patent Ductus Arteriosus (PDA): A condition where a fetal blood vessel fails to close after birth. While serious, it is the only defect on this list that can be surgically corrected, often using a minimally invasive Amplatz catheter, allowing the dog to live a completely normal life.
• Ventricular Septal Defect (VSD): A hole between the heart’s two ventricles. Depending on the size of the hole, dogs with a VSD can live normal lives as family pets, though they are usually not suited for high-endurance performance events.
• Subaortic Stenosis (SAS) & Pulmonic Stenosis: A narrowing of the blood vessels exiting the heart, known to be genetic in breeds like Newfoundlands. These dogs typically require lifelong medication and may face a shortened life expectancy.
• Tricuspid Valve Disease: A dysplasia or malformation of the valve on the right side of the heart. Currently, there is no surgical correction available in veterinary medicine and these dogs generally face a poor long-term prognosis.

Best Practices for Breeders

Because there are currently no DNA tests available for these genetic cardiac diseases, breeders must rely heavily on physical screening. Dr. Greer strongly recommends that echocardiograms on breeding stock be performed exclusively by board-certified veterinary cardiologists, as the imaging is highly user-dependent and easily misdiagnosed by a general practitioner.

Even with meticulous screening, it is still possible to produce a puppy with a congenital heart defect. Because of this, both Laura and Dr. Greer stress the importance of open, honest and gossip-free communication within the breeding community when these issues arise.