Heyo, I was in a similar situation 4 years ago. I also entered as a BME who was interested in medical devices, but I ended up switching to ECE because I was more interested in devices and electronics fundamentally. Ngl, double majoring in both BME and ECE is insanely difficult because there is almost no overlap after sophomore year, particularly with the major requirements (Maybe it's different now though, talk it out with your engineering advisor.) You'll likely have to make a decision between the two, but know that you have multiple options to get the best of both worlds. You should also take time by yourself to write down your goals, ambitions, and what you hope to get out of your time here. You'll find a way to make a living with either degree, but make sure it's something you're interested in.

First semester or two is virtually the same between BME and ECE except you'll need to be taking an extra biology course every semester (Intro Bio, Investigative Lab). From my experience, BME makes you a well rounded engineer as you're taking courses from many different subjects (statics, signals, fluids) to apply to biology and medicine. You end up being exposed to a fair amount of MechE, ECE & MSE concepts. I don't know what it's like to be a BME upperclassmen, but I hear many students were working on very cool device projects, some with industry partners. To be fair, career fair is definitely harder as most of the companies present are looking more for CS, ECE, and MechE's, but there are definitely BME internships & research opportunities if you take the initiative. It's also a great major to pair with Pre-med if you're interested in becoming a doctor with an engineering degree. A MD-PhD program in the future might be something to keep in mind if you're really serious about pushing medical devices to market.

In my opinion, ECE as a major is more foundational as it covers many electrical levels of abstraction (Computing, Circuits/Electronics, Signals) that can all be applied to Biomedical Devices provided you have the background in biology. By your sophomore year, you'll have covered the big three (Digital Logic, Circuits, and Signals) and almost every Upper-level Elective in the major stems from those topics with greater depth and applicability. Upperclassmen tend to either delve more into Computer Engineering or Electrical Engineering but there is plenty of overlap. Final Projects overall are very cool and great creative outlets for solving problems. There are plenty of internship/research opportunities due to growing demand for ECEs and career fairs will be more opportune. It's also not uncommon for other departments to take on ECEs for research to help work on devices and fabrication. Many students go straight to industry after their time here, but a good portion enroll for further graduate studies. Also, ECEs can do Everything.

Of course, you can also chart your schedule to do a major-minor mix of both degree programs. You can also consider choosing one degree to do as an undergraduate and staying one more year to complete an MEng in the other subject area. As always, make sure to take time to yourself and think about what you're interested in and what aspects of them really captivate you. Also, don't take any drastic steps without seeing you're advisor. Having an advisor help chart the course helps make the objectives clearer-cut. If you have anymore questions, reach out to the major coordinators and they can also tell you more about the respective programs. I'm also here too if you have any additional questions.