Question: How is heart failure different from a heart attack?
Answer: A heart attack is a relatively specific entity where part of the heart muscle, due to a lack of oxygen, is actually destroyed. In this country, most industrialized countries, the reason for that is there's an event that takes place in one of the coronary arteries -- the arteries that lay on the surface of the heart and supply fresh blood and oxygen into the heart muscle.
If one of those arteries has a significant obstruction or narrowing that then is totally obstructed by the formation of a blood clot, it impedes or stops the flow of blood and oxygen to an area of the heart muscle, and if it lasts long enough that heart muscle dies -- that's a heart attack.
Now, large heart attacks, or repetitive heart attacks and destruction, can eventually lead to heart failure, but heart failure can be caused by many other causes, or etiologies, also.