Heart-attack deaths have fallen 60 percent in three decades, according to Daniel Levy, M.D., director of the National Heart, Lung, and Blood Institute's Framingham Heart Study. Still, more than 57 million Americans suffer from cardiovascular diseases linked with heart attacks and strokes, according to the American Heart Association (AHA).

Knowing what causes heart disease and how you can prevent it can help you live a healthier, longer life.

Sudden cardiac death is the leading cause of death in adults in the United States. Knowing CPR may help you save someone's life. Learn more about CPR by taking this quiz.