In 1973, former Medtronic sales representative Albert Beutel founded Intermedics in Freeport, TX. The first product was a small, mercury-cell-powered pacemaker. In 1974 Intermedics introduced a lithium-powered version, and in 1976 it introduced InterLith which was hermetically sealed, and weighed just 65 grams. At the time, InterLith’s size was a breakthrough, and became a very popular device, solidifying Intermedics’ position in the industry.
The Circadia pacemaker was one of the very few devices that had a lead-borne thermistor to measure cental venous temperature (CVT) as a sensor for rate-response. A unique feature of this pacemaker was an iridium-oxide (IrOx)-coated button welded to the can. It was believed that this button would improve unipolar IEGM sensing and reduce unipolar
One of the indicators of metabolic demand that has been used for controlling the rate of pacemakers is central venous blood temperature (CVT). In 1983, Bill Cook and Dr. Neal Fearnot began to work under the Cook Pacemaker Company on developing the technology developed by Dr. Fearnot at Purdue University into an improved prototype for
Intermedics’ next-generation pacing platform would have been full of neat features such as: hemodynamic sensing (impedance-based hemodynamic sensor), autocapture (capture verification), autothreshold (self-tuning based on automatic strength-duration curve generation), high-quality digital telemetry, large-volume memory for electrogram storage, non-volatile memory for self-recovery and patient information, advanced noise detection, etc. My favorite feature though was “Patient Alert”.