People who have survived a previous heart attack or diagnosed with a heart disease are at risk to suffer from Sudden Cardiac Arrest (SCA). However, there are some cases like the ones you see on the news where seemingly normal healthy people & even professional athletes without prior indication of a heart disease suddenly suffer from a heart attack. Know more about a Heart Attack Risk on the InsideCardiacArrest.com website. There is also the informative video that explains about Sudden Cardiac Arrest & also the human heart.