The Electrocardiogram (ECG)What is it used for?
The ECG is the most commonly performed cardiac test. This is because the ECG is a useful screening tool for a variety of cardiac abnormalities; ECG machines are readily available in most medical facilities; and the test is simple to perform, risk-free and inexpensive. How is the ECG performed? You will lie on an examination table, and 10 electrodes (or leads) are attached to your arms, legs, and chest. The electrodes detect the electrical impulses generated by your heart, and transmit them to the ECG machine. The ECG machine produces a graph (the ECG tracing) of those cardiac electrical impulses. The electrodes are then removed. The test takes less than 5 minutes to perform. What does the ECG tracing look like? Click here for an example of an ECG, and for an explanation of what those squiggly lines mean. What information can be gained from the ECG? From the ECG tracing, the following information can be determined: • the hea