This records the electrical activity of the heart. The test is painless and takes about ten minutes. During the test you lay on an examination couch. A number of plastic tabs (electrodes) are placed on your arms, legs and chest. These detect the minute electrical signals that are produced by the heart muscle. The electrodes are connected by wires to a machine that records all these signals and prints them out on paper. The test indicates if there has been any previous damage to the heart muscle such as that caused by a heart attack. It does not detect the presence of narrowings in the coronary arteries. The test may also detect some changes in heart rhythm especially if they are long standing.