Teach you to understand the meaning of ECG leads

　　Electrocardiogram is one of the most widely used forms of examination in medical clinics. I do n’t know if you can understand the ECG lead. Let ’s take a look at the specific content with the EEG machine.

　　The lead animal body tissues and body fluids can conduct electricity. Place the recording electrode of the electrocardiograph on any two non-isoelectric parts of the body surface to record the image of the ECG change. This measurement method is called bipolar Lead, the measured potential change is the algebraic sum of the potential changes at two points on the body surface, and the analysis of the waveform is more complicated.

　　If you try to make one of the two measurement electrodes, usually the pole connected to the negative end of the tracing device, its potential always remains at zero potential, it becomes a so-called "irrelevant electrode", and the other measurement electrode is placed on a measurement Point, as the "probe electrode", this method of electroencephalography is called a unipolar lead. Since the irrelevant electrode often keeps the zero potential unchanged, the measured potential change only represents the potential change of the part where the probe electrode is located, so the interpretation of the waveform is relatively simple.

　　At present, monitor manufacturers use unipolar and bipolar leads when clinically inspecting electrocardiograms. There are 12 methods of electrocardiogram leads commonly used by EEG machines.

　　The standard lead is a bipolar lead and can only record the potential difference between the two electrodes. The electrode connection method is: one lead (referred to as mutual), right arm (-), left arm (+); second lead (referred to as Ⅱ), right arm (-), left foot (+); third lead ( Referred to as III), left arm (-), left foot (+).