The ECG leads: Electrodes, limb leads, chest (precordial) leads and the 12-Lead ECG

The ECG leads: Electrodes, limb leads, chest (precordial) leads and the 12-Lead ECG

The ECG leads Before discussing the ECG leads and various lead systems, we need to clarify the difference between ECG leads and ECG electrodes. An electrode is a conductive pad that is attached to the skin and enables the recording of electrical currents. An ECG lead is a graphical description of the electrical activity of the heart and it is created by analyzing several electrodes. In other words, each ECG lead is computed by analyzing the electrical currents detected by several electrodes. The standard ECG – which is referred to as a 12-lead ECG since it includes 12 leads – is obtained using 10 electrodes. These 12 leads consist of two sets of ECG leads: limb leads and chest leads. The chest leads may also be referred to as precordial leads. This article will discuss the ECG leads in detail and no prior knowledge is required. Note that the terms unipolar leads and bipolar leads are not recommended because all ECG leads are bipolar, since they compare electrical currents in two measu…

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