Blockages in the blood vessels to the heart can limit blood flow. If low blood flow lasts long enough, a section of heart tissue dies, a condition known as myocardial infarction or “heart attack.” Disruption of blood flow to the brain can be the result of blocked arteries, blood clots, or bleeding into the brain. If lack of blood to the brain lasts long enough, a section of brain tissue dies, a condition known as a stroke. People who have heart attacks are also at risk for strokes. However, the size of this risk is uncertain. It is also not known whether the risk for stroke after a heart attack has decreased over the years as better treatments for heart attacks and preventive care have come into use.