This short medical device industry news story illustrates several points: http://www.mddionline.com/article/st-jude-medical-buys-leadless-pacemaker-developer-nanostim-1235m?cid=nl.mddi01. These include:
Large medical device companies often grow and introduce new products by acquiring smaller companies. Most biomedical engineering jobs are at smaller, entrepreneurial companies.
Innovation and miniaturization of medical devices continues. Minimally invasive surgery continues to be a growth area in medical device development.
After over 50 years of experience and use, pacemaker leads are still problematic and need continued development. B.t.w., Wikipedia has a pretty good description and history of the pacemaker at http://en.wikipedia.org/wiki/Artificial_cardiac_pacemaker.
There are lots of biomedical engineering companies and jobs in the Twin Cities area.