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Electrocardiography (ECG) is a quick, simple, painless procedure in which the heart’s electrical impulses are amplified and recorded on a piece of paper. This record, the electrocardiogram (also known as an ECG), provides information about the part of the heart that triggers each heartbeat (the pacemaker, called the sinoatrial or sinus node), the nerve conduction pathways of the heart, and the rate and rhythm of the heart.
Usually, an ECG is obtained if a heart disorder is suspected. It is also obtained as part of a routine physical examination for most middle-aged and older people, even if they have no evidence of a heart disorder. It can be used as a basis of comparison with later ECGs if a heart disorder develops.
To obtain an ECG, an examiner places electrodes (small round sensors that stick to the skin) on the person's arms, legs, and chest. These electrodes measure the magnitude and direction of electrical currents in the heart during each heartbeat. The electrodes are connected by wires to a machine, which produces a record (tracing) for each electrode. Each tracing shows the electrical activity of the heart from different angles. The tracings constitute the ECG. ECG takes about 3 minutes, is painless, and has no risks.
ECG: Reading the Waves
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