An ECG is a test that detects and records the electrical activity of the heart. As a diagnostic tool, it can detect and locate the source of heart problems, including heart attacks, irregular heart beats, cardiovascular disease, or other abnormalities of the heart. An ECG procedure involves attaching electrodes to the skin on the chest, arms, and legs while the electrodes detect electrical signals of the heart, and a machine displays the signals on a computer screen and graph paper. An ECG may be a beneficial way to detect cardiovascular disease because it is a low-cost and non-invasive test that is widely available in the clinical setting.