A stroke is usually caused by a blockage of one of the arteries that carries blood to the brain. Sometimes with a stroke, there may be a small amount of blood flow that manages to get through or around the blockage, and it may be possible that the amount of damage from a stroke may be reduced by increasing this blood flow. External counterpulsation (ECP) is a procedure in which a machine uses electrical signals from the heart that are detectable on the surface of the body in order to time the inflation of cuffs (similar to a blood pressure cuff) that are wrapped around a patient's legs (calves, thighs and buttocks). Using a reading of the electrical activity from the patient's heart (an electrocardiogram, or ECG, monitor), the machine inflates the cuffs with air at just the right time during each heart beat, during diastole, in order to change the blood pressure in a way that has been shown to increase blood flow to the kidneys, skin, eyes, heart, and brain.