Chronic heart disease--heart attacks and strokes--causes more than 40 percent of all deaths in the United States. That's 950,000 people each year or one person every 33 seconds. Statistically more vulnerable with age, hundreds of men and women begin the struggle to manage or prevent its occurrence every day. So naturally it's on the mind of older Americans and the family members who cherish them. What exactly is heart disease--and what forms does...