Sorry to hear of your issues Jeff - been there, had that, coming up on 3 years ago now... The first month is tough - just take it steady, behave yourself and do what the Quacks said - it's a PITA about the car, but it's only 4 weeks - it'll pass - could have been way worse if they'd have had to crack the ribs open instead of stenting, can be up to 6 months in that case.
My advice - take whatever rehab they give you - my hospital offered cardio rehab physio sessions, which were pretty good - in my case it was a bit "low impact" considering my heart problem was brought on as a side issue from a bout of pneumonia that'd caused pericarditis, which in turn had damaged one of the arteries on the heart, and 6 months later "boom". Thing was, in my case I was pretty much asymptomatic - week before i'd been out on the bike and ridden just short of 100 miles in a day.
SO, after the heart attack, the clot and plaques removal and stenting, I was physically back to normal (apart from feeling knackered because of the ridiculous dose of Beta-Blockers they had me on)... BUT, where the cardio rehab came in was this, it allowed me to actually exercise, and get my heart rate up, WHILST being supervised by a couple of cardio nurses who could assess how I was, how safe it was to get to that point, and, critically, to set HR limits and monitoring points for me when I was signed off to ride my bike again at the end of the course. In short, it gave me the confidence to actually go out and exercise, and do what I needed to get "back to normal" without s***ting myself every time I felt my heart rate become slightly elevated.
Did it work... well - i'm still on some meds, the beta blockers have gone down from 20mg to 3.75mg daily (BIG decrease - they actually found that the dose expected for someone of my height, weight and age was slowing my heart rate to under 30 while I was sitting around or sleeping, which is dangerously low, so they've been gradually decreasing the dose over time, as I sit here my HR's hovering around 38, which would be low for a 10 stone marathon runner, so i'm expecting that my next followup will probably end with them trying 2.5mg daily) and basically, that's about it... I'm a bit slower on the bike, a bit steadier walking, but I'm still on this earth, not under it.
Strangely, I think it's left me a slightly different person - i'm much less "driven", much more patient, and much happier with my lot in the world than I used to be - i think lying on a hospital bed alone for 9 days, writing a will that basically disposed of everything I owned made me realise a) how much I actually had and b) how little I appreciated it - and sadly c) how few people numbered in the things I cared about column... So, when I was fixed, I knew what I had to do - I got rid of a load of the stuff that had been just hanging around because I was too idle to get rid of it - and more importantly, I tried to be a nicer human being, on the premise that people may like me more...
I'll be honest, getting rid of the impedimenta was easier.