Cardio?!

Ok, for more then a year i’m in and out for an workout. For one month I make my program, but I can’t see a results...

So now i’m traing this 2 week program for Busy people. But i’m so bad at cardio! I have a very bad problem with my heart when I make cardio. I’m feeling just very bad and that was the reason why I stop doing exercises in the past.

But now I want to finish this program and I have a question: is there ok if I do the low impact versions of cardio exercises?!

PS I was thinking with my doctor about my heart and there is no reason I can’t working out. She says that my heart is ok, and I can do whatever I want ;)