Heart related. To do with my heart?

Doctor just for reassurance, this has nothing to do with my heart? We see so many news these days, that someone just died of heart attack while on stage, playing, etc etc. all of a sudden, so i am just stressed. I have no knowledge about this, hence asking you, are these really sudden or buildup over time. As i have got all the tests done and all are normal, except for cholesterol which is just slightly high, very minimal, but i have never had it before. No other existing diseases as well. Hence i reached out to you, to understand that, how do heart problems occur, how long does it take to buildup and then show, and if there is anything like a sudden heart attack to a person who has healthy heart