I am a grad student in cardiovascular research [although less active at the moment]. I also recently had a few heart palpitations, that I sought medical attention for.
This included EKG's in the hospital, wearing a holter monitor, getting a stress test, and an echocardiogram. Really neat things for an interested researcher.
Every nonzero finite dimensional inner product space has an orthonormal basis. It makes sense, when you don't think about it.