Val
Ryder Cup Winner
Assuming you are making a decent recovery, then exercise is usually recommended to maintain good cardiac function and keep weight off. Golf is pretty good for that as a low intensity exercise.
Make sure you have taken meds with you if you will need some during the course of the round, some anti-angina pills if you suffer from that, and make sure someone in the group has a mobile phone just in case. If you are on a diuretic (water tablet) you might need a pit stop or two on the way round. Take some fruit or healthy snacks and try to skip the bacon sarnie at the turn.
Take it easy and take your time up steep hills and don't be afraid to tell the others you need a minute if you do. Don't regard the game as life and death, but as a good way to get out and enjoy something. You will probably play better that way anyway. If you smoke, STOP!
My coronary arteries are fine, but I had an episode of heart failure a couple of years ago, due to a viral disease of the heart muscle. At one stage I thought my ticket had been punched, but the diagnosis improved to a resolved acute myocarditis and shouldn't have any long term consequences. I had an angiography (look at the coronary arteries) as part of the investigation. That was fine, but is a rather weird experience seeing your heart with a wire going into it up above you on a TV screen.
This guy is worth listening to OP, he knows........