The construction of a fluid electrode and the method for adhering the electrode to skin is described in detail. The electrode is atraumatic, not encumbering, and remains attached to the skin for long periods of time during strenous activity. It was demonstrated that the electrical signal picked up by the electrode is not distorted appreciably by movement of skin beneath the electrode or by direct blows to the electrode.

Equivalent electrocardiograms are obtained with fluid and standard electrodes using conventional leads on subjects at rest. It is suggested that the fluid electrodes used with conventional leads may have application for monitoring the electrocardiogram in unusual circumstances, for example, on patients during and after cardiac operations.

When fluid electrodes are used on the precordium, electrocardiograms showing good electrocardiographic complexes during vigorous physical activity are obtained. Use of precordial fluid electrodes for determining pulse rates during various activities and/or for prolonged periods of time is described. Other possible applications for the precordial fluid electrodes are suggested.