There is an update on https://padiracinnovation.org/2017/05/03/early-and-low-cost-detection-of-heart-failure/

Basically it discusses of the need and challenges of writing a Viterbi function for heart sounds detection. I just wrote one in Java which looks good, but it needs to be improved in various aspects.
One improvement is indeed to port this Java implementation to a microcontroller, maybe on a Atmel device which includes a tiny Java machine. However this is planned for the end of the year, currently there are other stuff to work on.