An ECG, referring to a standard 12-lead Electrocardiogram, uses ten electrodes (or nodes) placed on the patient's body. These electrodes detect the electrical activity of the heart from different angles.
While the ECG produces 12 "leads" or views of the heart's electrical activity, it's important to differentiate between leads and electrodes (nodes). The 12 leads are derived from the signals picked up by the 10 electrodes through specific calculations and combinations.
Here's a breakdown:
- Electrodes (Nodes): These are the physical sensors attached to the body. Ten are used in a standard 12-lead ECG.
- Leads: These represent different views of the heart's electrical activity. The 12 leads are calculated from the signals received by the 10 electrodes.
The electrode placement is as follows:
- Limb Electrodes: Four electrodes are placed on the limbs (right arm, left arm, right leg, and left leg).
- Chest Electrodes (Precordial Leads): Six electrodes are placed on specific locations on the chest.
Therefore, although a 12-lead ECG provides 12 different viewpoints, the system only requires 10 physical nodes (electrodes) to function.
