Well, before I came to work in my prsent job writing programming tools for programmers to program with, I spent nearly a decade helping design hemodynamic patient monitors for Cath Labs, Telemetry systems for Cardiac Rehab, data transport mechanisms for Pacemakers, and Holter systems for cardiac patients (now being used in the Space Program, oddly enough)...
But, I don't do that any more. I kinda miss it though. The only saving grace is that I know the technology will be there when I have my major cardiac event down the road ;0)