One of my best friends for more than 30 years underwent open-heart bypass surgery a few weekends ago, and it was a bit of a wake-up call for everyone involved. 

I have a new appreciation for the complexity of the heart from both a physical and emotional perspective. I also have an increased appreciation for surgeons and the miracles they can work in the operating room. 

My friend had the first 4 1/2 inches of her aorta replaced with a Dacron graft, and she is walking around, doing great weeks later — amazing!

This month, I thought I would talk about this magnificent organ and how it works for our pets. The heart is one of the strongest muscles in our pets’ bodies and performs the vital function of delivering oxygen to all of the tissues. 


Heart conditions

The heart has four chambers divided by valves. Oxygen-poor blood from the body comes into the right side of the heart and is routed into the lungs, where it receives oxygen. The blood then returns to the heart with fresh oxygen and is pumped out from the left side of the heart into the aorta and to the tissues. 

The one-way valves between the heart chambers keep the blood headed the right direction and make sure none of the heart’s efforts are wasted. It is the failure of these valves that cause the most common type of heart disease in animals (75 percent): degenerative-valve disease. When these valves are defective, they no longer seal completely between each pump of the blood, and the blood leaks back into the chamber it came from. 

Your veterinarian can hear a heart murmur when valvular disease is present. The murmur comes from the blood leaking back through the valves. 

Smaller-breed dogs have a higher incidence of valve problems than big dogs and cats. King Charles spaniels have an extra-high incidence.

The most common type of heart disease in larger dogs is dilated cardiomyopathy, an inherited condition in which the biggest chamber/muscle of the heart, the left ventricle, loses its ability to contract to pump the blood into the next chamber. This causes the blood to back up and creates congestive heart failure. 

This heart disease is more difficult to pick up in our pet patients because there is no murmur present. We usually find evidence of an enlarged heart on X-rays. 

Heart disease is a disease that sneaks along and doesn’t show itself until it is pretty advanced. Signs of heart disease are exercise intolerance (your dog doesn’t want to walk as far as it used to), weakness, lethargy, cough or respiratory problems, labored breathing and sometimes syncope, like fainting, and can appear as stumbling or mini-seizures. 

The good news is that when an early diagnosis is made, medication can prevent heart disease from becoming worse for long periods of time. 

Surgical correction of heart problems for pets is not yet as common as for people but is being performed and will someday probably be as commonplace as it is for people. 


Pet of the Month

Our Pet of the Month this month is Sophie, a very sweet, cooperative, 11-year-old, female, spayed, miniature schnauzer. Sophie has a recent history of liver problems and pancreatitis, but this time, she was treated because that she was not acting like herself, having some difficulty breathing, and her owners thought she might be having seizures. 

On the way from the car into the clinic, she fell over and seemed unresponsive. 

During Sophie’s exam, I noticed that she had a new, strong heart murmur, which is very unusual. 

Her heart did not appear enlarged in the X-ray, but there was a small amount of fluid in her lungs, which was causing her breathing problems. I explained that I thought the “seizures” might have actually been syncope: a lack of oxygen to the brain that occurs with heart disease. 

Sophie was sent to a cardiologist for an echocardiogram, and it was discovered that her “heart strings” (the chordae tendinae — little tendons that are responsible for the function of the heart valves) had ruptured, causing her valves to prolapse. This explained why she had a new murmur.

Sophie is now on medication for her heart disease, which has helped her breathe easier. If she were human, she would be undergoing heart surgery to reconstruct these little “heart strings,” but such surgeries are still not routinely performed in veterinary medicine. 

DR. TERI BYRD practices at the Madison Park Veterinary Hospital (