Watch more How to Understand Heart Disease videos: http://www.howcast.com/videos/512501-What-Is-Heart-Disease-Heart-Disease What is heart disease? That’s a great question. In general, it implies any condition where the heart is not normally functioning. So I would say there’s three basic categories of heart disease. One would be ischemic, or atherosclerotic heart disease and I think that ‘s what most people mean when they’re talking about heart disease. That’s the build up of cholesterol plaque inside the arteries that can eventually lead to a heart attack and a weakening of the heart muscle. If we go to the next, sort of category, that would be valvular heart disease, where the valves, which are doorways in the heart, don’t work well. They’re either stuck, or leaky and they can also lead to weakening of the heart muscle. A third category would be cardiomyopathy, which literally stands for weakened heart muscle, or bad heart muscle. And the heart muscle can be weakened for many different reasons, and they all lead to a final common pathway of heart failure. And I think, in essence, those are the main categories of heart disease. There are, of course, a lot more we can talk about. That gives us a good beginning.