"Blockage of the heart" is not a credible condition. You have to find out exactly what s wrong with your heart and get advice from a cardiologist regarding the safety of flying. I had a prolapsed mitral valve and was quite happy doing aerobatics in a glider, so ordinary flying in a passenger jet was no challenge. But YOU have a responsibility to get better acquainted with your actual cardiac condition. "Blockage of the heart" is nonsense because that means "dead by sun down", so get to know exactly what is wrong with you as your life may depend on it!!!!!