Heart diseases is an umbrella term for a variety of different diseases relating to the heart. Such afflictions include diseases affecting the blood vessels that supply the heart, deterioration of the function of the heart, inflammation of the heart muscle or diseases related to one or more heart valves. Far the most common type of heart disease is called atherosclerosis, a number of conditions in which an artery wall thickens due to a buildup of materials. The most severe manifestation of atherosclerosis is the stroke and the heart attack.