Walking through MD&M is always fun because component and assembly companies often display implantable devices that never made it to market or technologies that they are incorporating into brand new devices that have not yet reached prime time.
AJ Medical’s CardioAlarm is a sample of an implantable device that didn’t quite made it. It was meant to automatically detect cardiac arrest and use a wirelessly-connected pager-like device to alert bystanders and call 911.
As many other alert implantable medical devices, CardioAlarm didn’t make it to market. The latest victim being Angel Medical needing to seek Chapter 11 bankruptcy protection soon after achieving FDA approval for its Guardian Implantable Heart Attack Monitor, although hopefully this is just a financial restructuring exercise to gear up for full commercialization of the device.
I can’t remember exactly where I found the picture of a Pacesetter model BD102 VVI, but the story behind it is documented by Kirk Jeffrey in “Machines in our Hearts”:
In 1965, Australian medical device pioneer Noel Gray established Telectronics – Australia’s first manufacturing facility for producing pacemakers that were designed in-house. Telectronics was an innovative developer, achieving some major successes in the early cardiac pacing field, for example, Telectronics’ leads allowed narrowing the pacing pulse to its current nominal of 0.5 milliseconds; encapsulating the pacemaker in titanium instead of epoxy; using a microplasma weld to join the two halves of the pacemaker capsule; creating one of the first rate-responsive ‘demand’ pacemakers; and isolating the pacemaker’s battery in a separate compartment to deal with the problem of leaking mercury-zinc batteries. 
