Electrocardiography (ECG) is an examination, in which the electrical activity of the heart is recorded. In this way, the doctor can evaluate the heart function and determine whether there are defects. The registration takes place in the form of a graph, the electrocardiogram.
Electrocardiography is used in case of symptoms in the chest area, which may indicate a heart disease. The examination provides information about the heart function, the heart rhythm, the size of the heart and the oxygen supply. The doctor may also read old or recent heart attacks and disorders caused by malfunctioning heart valves. The ECG does not provide information on the mechanical pumping function of the heart.
The heart is a muscle, which pumps blood through the body by contracting. The heart muscle is triggered to contract by a small electric current that activates the heart and runs like a wave across the heart muscle. These electric currents are not felt, but may be recorded on the surface of the body. The currents are converted into a signal by an ECG device (electrocardiograph).
During the examination, the laboratory technologist pastes ten electrodes onto the chest, arms and legs. In order to let the electrodes have good contact with the skin, they are moistened in advance. The electrodes are connected to the ECG device and record the electric currents that make the heart muscle contract. The examination takes about 10 minutes.