The recorded waves show the shape, texture and movement of the valves and the size and function of the heart muscle and chambers. The test can take up to an hour and is painless. It provides information about disease of the heart muscle for those who have suffered a heart attack or heart failure and to assess people with disease of the heart valves. Doppler echocardiography measures the speed of the flow of blood in different parts of the heart. Occasionally, echocardiography is carried out after the heart is put under stress either with exercise or a drug - stress echocardiography.
Patients lie in a short tunnel-like machine which contains a cylindrical magnet.
Short bursts of magnetic fields and radio waves create images of parts of the body as required. It is useful to evaluate disease of the aorta - the largest artery in the body and involves little potential risk to patients. In stroke patients, it gives valuable information about the location and extent of brain injury. Cardiac catheterisation is often used to assess whether people with angina require surgery. The test gives vital information about blood pressure within the heart, how much oxygen is in the blood, the function of the pumping chambers and valves, and the exact severity and positioning of any narrowings in the coronary arteries.