There are several ECG digitizing software in the market as well as software to measure ECG intervals that can work along with the digitizing software. An examples for these software (which you can download free demo) are available at " http://www.amps-llc.com/website/index.php?option=com_rokdownloads&view=folder&Itemid=21". The time needed to scan the ECGs is not trivial, and the yield in terms of reading results is limited. So it is not that much practical for large volume of paper ECGs specially if the interest is to obtain several measures (i.e. ECG classification, intervals, etc..)
Thank you for the information! I can see that this process is going to require a substantial amount of time! I believe that the study PI (Dr. Ensrud) has already been in touch with you! :)