If you have heart issues and are at risk of a heart attack then yes you might die of a heart attack in mid air before you hit the ground.
But you're likely to be alive the whole time on the way down from a very high fall or jump and when you hit the ground then you will likely die right away.
People go skydiving and are falling too the ground and they don't have heart attacks so the act of just falling from the sky or falling off a tall building shouldn't cause a heart attack.
Most people who jump from a building and die usually die as a result of them hitting the ground.
Just like the people who jumped out of the buildings in New York on 9/11 they died as a result of hitting the ground and not because of the fall itself.