Matters of the Heart: Congenital Heart Disease

Humans and animals often have similar health problems.  One example of this is Congenital Heart Disease. Congenital Heart Disease refers to a problem the animal is born with.  There are multiple types of Congenital Heart Disease: valve malformations or dysplasia, valve narrowing or stenosis, abnormal openings between the heart chambers or septal defects, and patent ductusarteriosus.

Patent ductusarteriousus (PDA) is the most common among dogs, said Dr. Ashley Saunders, assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVM).

"There are anumber of diseases that your dog can be born with, patent ductusarteriosus is the most common in dogs," she said.

PDA is caused when the ductusarteriosus, an arterial connection between the aorta and pulmonary artery, doesn't close properly after birth, Saunders said.  This results in blood being pumped back through the artery instead of through the rest of the body.  

Saunders added that different breeds such as German shepherds, miniature poodles, cocker spaniels, Pomeranians, collies, and Shetland sheepdogs are more susceptible to the disorder. Female dogs are also predisposed to the disorder.

Most dogs with PDA have a heart murmur that the veterinarian will hear upon routine checkup.

"Most veterinarians will hear a heart murmur when the dog is taken in for a routine vaccination or first exam," Saunders said.

After hearing the heart murmur, an x-ray is done to evaluate the heart size and possibly fluid build-up in the lungs.  A cardiologist would get an ultrasound or echocardiogram of the dog's heart to examine the blood flow through the ductusarteriosus.

"Based on the symptoms and the murmur, we will do tests to determine which congenital disease the dog has," Saunders said. "A lot of times, we will have to do a heart ultrasound to make a definitive diagnosis."

Generally, surgery is the treatment for dogs with PDA.  The Small Animal Hospital at the CVM is known for fixing PDA with minimally invasive surgery, Saunders said.  If the animal has surgery, their prognosis is great with a greater than90 percent survival percentage.  

If undiagnosed and untreated, PDA can lead to heart failure.  Since PDA leads to heart failure, 60 percent of dogs die when PDA is untreated. Signs of heart failure are difficulty breathing, coughing, and exercise intolerance.

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Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the Web at /pettalk.

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