Discuss the types of electrocardiographs used in medical offices. Then discuss electrodes and the use of electrolytes to ensure good conduction from the skin to the electrodes. Ask: What is the main advantage of prepackaged disposable electrodes? (Less mess and a more consistent tracing with less artifact because the same amount of electrode gel is placed on each electrode.) How many leads does a standard electrocardiograph have? (12) Review the purpose of the electrocardiograph controls. Emphasize that the electrocardiograph should be standardized before use. Ask: How is the standardization of this instrument checked? (The standardization control is pressed. The stylus should move up ten small squares and remain there for 0.08 second.) Discuss the use of the speed selector and point out that the normal speed is 25 mm per second. Ask: Why might the speed need to be adjusted? (If a patient has a rapid heartbeat, the ECG speed may need to be faster to provide enough separation for the deflections to be read clearly.)