Peter, Sorry to hear you are unwell -- the good news -- I found myself in the same boat 18 months ago and am the proud possessor of 8 stents!! I have an e-bike and found it brilliant for rehab and was back to basic normal in about 8 weeks. I now do about 130Kms on the bike each week and with a Fitbit device monitor my heart rate in real time - if the rate goes above the level I have been told to keep, I just increase the amount of assist the bike gives - simples!!!!
I now do exactly what I want - will go to Austria after Christmas for a week's cross-country skiing(did it last January too!)so I hope you recover as quickly as I did -- DO go to the Heart Rehab course, if offered one - I found it a real help.