We're lucky in that information covered by HIPAA (e.g., the medical record) is handled by our academic partner at UCSF, the Health eHeart study (health-eheartstudy.org).

I think it's a bit of a misconception that you always need an extremely low error rate in medicine. Many of the existing tools are quite poor. CHADS-VASC, for example, is the primary score that cardiologists use to prescribe blood thinners, and its c-statistic is an... unimpressive 0.673. (0.5 is random, and 1.0 is perfect.) Given that the side effects of unnecessary blood thinners include brain hemorrhage, even a modest improvement to CHADS-VASC could save hundreds of thousands of lives.

So my message to data scientists considering going into healthcare is... please come! You don't have to achieve perfection to save lives. Even a mediocre statistical model would be an improvement in so many areas.