They’re smaller and slimmer than ever. And now a new miniature pacemaker travels deep inside the heart, where doctors hope it will be protected from damage and infection.
Mary Moore, Lamb’s wife: “Gradually, I would be walking someplace and there he was behind me where in the past he was always ahead of me. It didn’t occur to me that it was his heart. I just thought he was getting older.”
But it was Lamb Moore Jr’s heart that was slowing down. The 75-year-old’s heartbeat was weak – limiting his ability to pump blood fast enough.
Dr. Hemal Nayak, University of Chicago Medicine Cardiac Electrophysiologist: “We can treat that and restore some of that heartbeat with a pacemaker.”
No bigger than a couple of silver dollars stacked together, a standard pacemaker sits in the chest wall. Wires lead from the battery to the chambers delivering extra power to boost the heartbeat. Mr. Moore had the device implanted twice but both failed due to infection.
Lamb Moore, Jr: “Swelled up so big, had to take it out right away.”
It’s not a common risk.
Dr. Nayak: “Overall it’s low, anywhere from one to two percent. But still, when it happens, it’s a disaster because invariably the whole system needs to be removed.”
After two strikes, Mr. Moore needed another option. Cardiac electrophysiologist Dr. Hemal Nayak offered a bit of hope.
Dr. Nayak: “It’s about the size of a triple-A battery, and within it contains the computer chip, the battery of the unit, in a very small package.”
It’s called Nanostim, a miniaturized pacemaker being tested at University of Chicago Medicine.
Dr. Nayak: “Here, this is embedded within the heart, in the heart’s cavity, so it’s not touching any skin, it’s not connected to anything. So we hope it’s going to show reduction in infection.”
Just like doctors place a stent in the heart, the Nanostim is implanted – and removed, if necessary -- via a catheter ... no need to cut a patient open.
Dr. Nayak: “It is threaded up the leg in the inferior vena cava, up into the right upper chamber, and then the device is screwed into the wall in this region right here.”
With no wire leads, the all-in-one device powers an electrical current from inside the heart.
Dr. Nayak: “These screws are conductors and they provide the connection to the heart to stimulate the heart and pace the heart
Mary Moore: “It’s something he needs. The condition will not get any better. I said, ‘Let’s go for it.’”
Mr. Moore had the tiny device implanted in mid July. Knowing the experimental treatment came with risks, he still hoped it would work for him.
Lamb Moore, Jr: “You would be leery about it, but you have to try something.”
Dr. Nayak: “There’s always the risk of the device being moved or dislodgment. There’s the risk that we could potentially perforate the heart in our implant. Few of those have been reported in Europe, where this device is now being utilized and studied. But, fortunately, we have not seen many of those in the United States.”
In European studies, there were two deaths reported out of 200-plus patients due to perforations in the heart. But the device maker says the adverse events were due in part to inappropriate patient selection and operator inexperience. Still, Dr. Nayak says he is excited about the new pacemaker.
Dr. Nayak: “The ease of the technique of placing this, the comfort of the patient, not worrying about lead malfunction, lead failure. I’m hoping it’s going to show reduction in overall infection.”
Mary Moore: “When I walk down the street now, instead of ten paces behind he’s only three. So that’s nice. He’s doing real well.”
Lamb Moore, Jr: “I don’t have no restrictions on me at all. I can drive, drive the lawn mower, cut the grass. Back to normal.”
The tiny pacemaker isn’t for everyone – only patients who require single chamber pacing. The device is already in use in Europe, and researchers here are testing it at centers throughout the country.
If you’d like to learn more about the University of Chicago Medicine’s pacemaker study, contact Al McAuley, Senior Research Project Professional, Heart Rhythm Center Research Office, (773) 702-5877.