Heart disease is the No. 1 killer of American men and women. But, it doesn't have to be. There are many steps you can take to prevent and manage heart disease and live a long, healthy life. If you have heart disease, are concerned about getting it, or if you are looking out for the health of someone you love, this guide can help. WebMD has teamed up with experts from The Cleveland Clinic to bring you the information you need.