Is it possible to do an electrocardiogram with one electrode? Or is it neccesary to have multiple electrodes? I do not understand much about EKG, so I am sorry if this question sounds naive.


2 Answers 2


Short answer
Any electrophysiological recording of potentials, including the electrocardiogram (ECG or EKG), measures a potential difference. Hence, two or more electrodes are necessary.

The ECG measures the rhythmic voltages changes generated by the heart muscle. Voltage is defined as a potential difference between two points. Therefore, a voltage is always measured across two or more points. For example, when you measure voltage when holding one out of two recording electrodes to one of the two poles of a battery, nothing will be recorded. This, because no current will flow through the potentiometer by connecting just one pole of the battery. Likewise, electrophysiology needs at least two recording channels to determine the voltage differential between the two. One channel is typically called the active electrode, the other the reference. The configuration of active and reference determines the polarity of the recorded voltage. Often a ground electrode is added to remove background noise.

  • $\begingroup$ This might sound odd but I was wondering, is it possible to make something like voltage clamp with ECG? $\endgroup$
    – Dexter
    Sep 26, 2015 at 3:48
  • $\begingroup$ @Dexter - Theoretically yes, by adding stimulation capabilities to the electrodes. However, ECG records muscle activity typically by surface electrodes, and to voltage clamp the heart large currents would need to be injected. That would be akin to a defibrillator :) $\endgroup$
    – AliceD
    Sep 26, 2015 at 3:51

Actually, yes you can. But you will not be able to make use of what you're seeing. There are six leads which are unipolar: V1, V2, V3, V4, V5 and V6. Any of these can monitor electrical activity in the heart without a second lead being present. In this instance, V1 or V6 would probably be the best for rhythm identification and monitoring.


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