What is the difference between a heart attack and cardiac arrest?

A heart attack is a area of the heart that goes without oxygen from a narrowing or blockage of the blood vessels supplying it. Cardiac arrest is caused by a blockage of blood in a artery that supplies a huge area of the heart (the Left anterior descending artery supplies the left ventricle, if you block this one, the left side of your heart stops working and you die) I imagine MJ has this left blockage or died from not breathing leading to cardiac arrest from medication his doctor gave him