Four years ago, while hanging out in the living room with his family, Bear just fell down for no discernible reason. “Looking back, we had heard him fall several times out of our sight, which we attributed to him slipping on our hardwood floors,” says Marsha. But she was shocked to watch him drop right in front of her. So she took Bear to the family vet, OSU alum Dr. Dan Lewer, who detected a problem with Bear’s heartbeat and immediately contacted the cardiology department at the OSU Veterinary Teaching Hospital.
The following Monday, Bear was in surgery and a pacemaker was implanted next to his heart. The procedure went well and, after several weeks of rest, he resumed normal activity. “He was out running and playing and enjoying life to the fullest,” says Marsha.
Pacemakers are relatively simple devices that consist of a battery, a computerized generator, and a wire. The wire, also called a lead, feeds through a vein connecting the generator to the heart. When sensors on the lead tell the computer that the heart is not beating properly, the generator sends electrical pulses to the heart.
Each year 600,000 pacemakers are implanted in humans. But, despite 78 million pet dogs in the U.S., only 300 pacemakers are implanted in dogs each year.
Veterinary cardiologists are still researching, studying and working on ways to optimize pacemaker procedures in dogs. Bear was about to help them advance veterinary medicine.
Last year, Marsha noticed that Bear’s pacemaker had moved upward in his neck; she could see and feel it, and was very concerned. In humans, pacemaker migration is rare and thought to be caused by vigorous activity or even a heavy bump. A big, happy dog like Bear has a life full of both.
Marsha took Bear back to OSU where Dr. Nicole LeBlanc confirmed his pacemaker had moved. She decided it was best to remove the old pacemaker and implant a new one in his abdomen.
When pacemakers are removed or repositioned, it is difficult to remove the lead because scar tissue firmly fastens it to the vein. Pulling on it until it comes loose can cause the lead to unravel and increases the risk of blood clots, so it has been standard procedure for the lead to be cut and left in place when a pacemaker is moved. In most cases, this causes no problems.
Recently, human medicine has developed new tools and procedures for extracting abandoned pacemaker leads but, at the time of Bear’s surgery in 2012, there were no tools for doing it in dogs so the lead from Bear’s old pacemaker was left in place.
Bear Inspires New Procedure
At Bear’s post-surgery checkup, Dr. LeBlanc found the new pacemaker working well but chest x-rays revealed the abandoned lead from his old pacemaker had looped into his pulmonary artery and was disrupting his heart valve. That was the bad news. The good news was: Dr. LeBlanc knew there was new technology that now made extraction of the lead possible – it just hadn’t been done yet.
Dr. LeBlanc discussed the new extraction procedure with Marsha and Gary but they didn’t know whether to go forward. After four surgeries and a struggle with reoccurring infections, Bear had been down a tough road. “I was concerned about putting him through too much,” says Marsha, “so I asked him for a sign that he wanted to do this and wanted to keep going.”
The sign came when Bear left ICU and came bounding into the waiting room, dragging his helper. “Shanna, a fourth-year student, was basically skiing behind him,” says Marsha. “As sick as he was, he made it clear: ‘Hey, I’m not done yet. I have more walks to take, more lakes to swim in, and more beaches to visit.’” They signed the surgery consent.
In preparation for surgery, Dr. LeBlanc consulted with Cook Medical, a world leader in innovative medical device technology. They sent her specialized equipment and even flew an expert to Corvallis to assist with the procedure.
OSU veterinary cardiologists Drs. Katherine Scollan and David Sisson performed the surgery. A description of lead extraction surgery is not for the feint-of-heart (so to speak): They opened a vein in Bear’s neck to allow passage of surgical instruments into his heart. One instrument grasped the lead while locking devices were attached to keep it from flexing. Then a tubular stainless steel sheath with a sharp tip was pushed through, cutting the fibrous tissue holding the lead and, at the same time, encasing it. The sheath-covered lead was then pulled through Bear’s cardiovascular system and out of his heart.
Immediately after surgery, Bear was monitored closely for signs of arrhythmia, hemorrhage, and other risks. When no serious issues presented, he was sent home to his family. The first-ever lead extraction on a dog was a big success.
“We are so grateful to have Bear in our lives,” says Marsha. “We are deeply grateful to everyone at OSU Vet Med, who assembled a small village of caring individuals to help create a healing miracle for Bear. So many people, so much kindness, all to heal a lovely dog who still has a zest for life and is ready for his next adventure.”