One of the best exercises is star jumps, they used those in our rehab group. Just start off doing 15-30 seconds of those because they get the heart going very quick. You should walk around the room for a minute or 2 first.
Just do anything you can to increase your heart rate, it doesn't take much. Sit ups, push ups, squats are all great for increasing heart rate. If you check my exercise tracker here you'll see I do calisthenics quite often. It only takes 30 mins per day combined, helps keep your cardiovascular system fit.
Just keep moving as exercise helps keep blood pressure low and HDL high.
Jon
It's a catch 22, the longer you sit around not doing much, the more your body will basically become unfit and struggle to do anything. Muscles become useless if not used and become much harder to use.
Hi, Just a little suggestion concerning exercise. If you have no other choice why not just walk in the house. Even if you walk around the room for 1/2 hr or in increments of 15 min 2 x's a day. At least your moving around. Then slowly increase your time and pace to what you can handle.
I don't know what your heart problem is and I'm certainly no doctor but I think you should move around and get your heart rate up a little and your circulation going.