Two years ago we heard about the Nanostim, a pacemaker that's less than 10 percent the size of a regular model. While it's pretty darn small, Medtronic's just-announced Micra TPS (Transcatheter Pacing System) is reportedly even tinier. Billed as the world's smallest pacemaker, it's described as being the size of a large vitamin capsule – and it can be implanted using a catheter.
Conventional pacemakers are surgically implanted in a pocket under the chest skin, and produce a visible protrusion. They're connected to the heart by electrical leads, which can sometimes lead to complications (such as if the leads get detached).
Like the Nanostim, however, the self-contained Micra TPS has no leads. Instead, it's attached directly to the heart wall using built-in tines, delivering electrical stimulation via an electrode on one end.
It's implanted by running a catheter up the femoral artery into the heart, via a small incision in the inner thigh. This leaves considerably less scaring than the chest pocket method, plus there's no bulge under the skin to give away its presence. Once it's installed, a catheter can also be used to reposition or remove it if needed.
Its battery should be good for approximately 10 years of use, and the device is safe for full body MRI scans. A Medtronic representative told us that it's intended for single-chamber pacing, in which it stimulates the right ventricle – patients who require dual-chamber pacing will still need to go with a traditional pacemaker.
The Micra TPS has not yet been approved for use in the US, although it has just received CE Mark approval for sale in Europe.