I found this Federal Registry from 1997 on the cardiovasular system. It's from the last time they did an evaluation on the cardiovascular ratings. It's pretty informative as it describes reasonings behind certain ratings.
In my case i'm using the very end of page 7 thru the very begining of page 8. The IPEB rated me at 30% for having a AICD (defibrillator) in place and here it states that it is to be 100%.