I don't believe the pacemaker example is necessarily a great one. In order to meet the risk-mitigation requirements for device approval, you have to document th

I don't believe the pacemaker example is necessarily a great one. In order to meet the risk-mitigation requirements for device approval, you have to document the design and the various decisions that led you to that point. If you're working in an agile fashion, you end up documenting a bunch of stuff that isn't in the product and doesn't get used, and at best your technical file is going to be much bigger than it needs to be (at worst, you confuse the assessor and don't get approval). That's not to say you can't use agile methods, but I think the sensible way would be to use agile to explore the solution space and learn what to build, but continue using a formal methodology in parallel construction to document the development of the device.