4470 El Camino Real

Los Altos, California 94022

Veterinarian Always on Duty

Pacemaker Implanted in Goldie

The Beat Goes On...

Goldie, a thirteen year old spayed Weimaraner, was brought to Adobe Animal Hospital for what the owner described as seizures. The owners stated that while Goldie was laying down, her front legs would extend out while her neck would extend back, she would also sometimes fall to the ground while walking, and her appetite had decreased. These symptoms had been going on for about a month, but in the days prior to bringing Goldie in, the incidences had progressed to many times a day.

Upon presentation to us, Goldie was a very nervous dog. Although she was older, she looked very good for her age. The only significant finding upon my physical examination was that she had a very irregular heartbeat. To better assess the heart, I performed an electrocardiogram (EKG). This test would help us determine the electrical rhythm of Goldie's heart.

In a normal heart, regular beats occur because of an electrical signal which is produced in a special area of the heart. In Goldie's case, her heart was not beating normally because this electrical signal was not being conducted through the heart correctly. Thus her atria and ventricles were functioning independently of each other. In this case, the only diagnostic test we had to perform was an EKG. This led to the final diagnosis of third degree atriventricular heart block.

Blood carries oxygen, and when the heart does not pump correctly, the brain does not receive enough oxygen. This is what led to the "seizure-like") symptoms that the owners observed; they were actually episodes of syncope (syn'-ke-pee) or fainting.

There are two potential treatments for third degree AV block. One is drug therapy with Atropine, however, not all animals will respond well to it. Atropine increases the heart rate, and hopefully creates improved blood flow. If an animal responds well, s/he will be on the drug for the rest of his/her life. If the drug therapy does not prove to be effective, then the other option would be to place a pacemaker into the heart. A pacemaker fires an electrical impulse at a constant rate, making the heart contract more regularly.

Goldie was given an injection of Atropine and then we performed another EKG. Unfortunately, she failed to respond. The owners opted to have a pacemaker placed into Goldie's heart. A pacemaker was obtained from a medical supply company, the same kind used in humans. Most have a ten year working life span, after which they would need to be replaced.

Surgery was performed on Goldie. We approached the heart from the side of her chest between the ribs. Once the chest was opened, the heart was identified and the tissue surrounding it (pericardium) was opened. Next, the pacemaker lead was inserted into the muscle of the heart. The chest was closed and the pacemaker unit (the size of a silver dollar) was placed under the skin. The unit was set to fire at a rate of 120 beats per minute.

Goldie was released that night and was sent home with pain medication. We rechecked her one week later. The owner reported no more signs of syncope and Goldie was also eating better and seemed to be feeling well. Unfortunately, two weeks later, Goldie became ill. She was having trouble breathing and could no longer stand or walk. Upon physical examination, I found that fluid had built up in her lungs and her heart was not contracting normally. Apparently, the lead to the pacemaker was not in good contact with the heart muscle, therefore, the heart was not pumping blood efficiently. This caused a back flow of fluids into the lungs. Medical therapy was instituted and when Goldie was stable enough a second surgery was performed to replace the pacemaker lead.

Happily, I saw Goldie two weeks after her second surgery. She was bouncing off the walls in the examination room. Her heart rate was 120 beats per minute, and the owners reported that she was acting like a new dog again. She is more active and even wants to play with the Frisbee again.

Date: November 1998

Species: Dog

Diagnosis: Third degree atriventricular heart block

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