Scott Harden built a DIY ECG project with AD8232, that is available on Github:
Every few years I revisit the idea of building an ECG machine. This time I was very impressed with how easy it is to achieve using the AD8232, a single-lead ECG front-end on a chip. The AD8232 is small (LFCSP package) but breakout boards are easy to obtain online.
Project info at SWHarden.com.
Check out the video after the break.