> by a quick back of the envelope calculation a positive test result is still 5× more likely to be a false positive than a true positive. With those odds, I don't think many cardiologists are going to answer the phone. You'd still need an EKG to diagnose AFib.

This is a good point, and certainly nobody should go directly to a cardiologist based on these results. It seems that this would be a good system to recommend that people get an EKG done, though.