The heart sends electrical signals to the entire body. Electrocardiography is a procedure to measure these electric signals with the help of sensors that are placed in different parts of the body. In a conventional diagnostic electrocardiograph (ECG), 10 electrodes are placed as sensors in the legs and surface of the chest of the patient. The signals, then, received by these sensors are recorded and the overall information regarding the magnitude and direction of these signals is translated into a graph by the computer which is displayed on the monitor. The doctor observes the condition and functioning of the heart with the help of these graphs.
The main components of an electrocardiograph is the instrumentation amplifier which takes the voltage difference between the leads or sensors and helps amplify and translate the signal. Besides, it also consists of a screen to display the graph, a keyboard and a printer to get the results printed. New age electrocardiographs consist of special features like voltage protection for both the operator and the patient, defibrillation protection and electrostatic discharge which is again a form of voltage protection. In certain electrocardiographs, additional circuitry to reduce common mode interference is also present.
Symptoms like chest pain, shortness of breath, weakness, frequent fainting, nausea etc. usually prompt the doctor to recommend an ECG. Besides, in case of a person undergoing a surgery, heart disease patients, people with pacemakers and older people, ECGs are used for constant monitoring the functioning of the heart. It is primarily used to diagnose heart conditions and heart attacks, detect overdose of drugs or conditions that cause an imbalance of electrolytes in the body. As useful and important as stated, however, the best part of this device is that it has no side effects, risks or complications associated with it during testing.
Disclaimer: The information given in this write-up is purely for educating the reader. It is not meant to be a substitute for any advice from a medical expert.