An easily applied and removed dry annular suction electrode

A new type of self-retaining dry metal electrode for the electrocardiogram (ECG) is described which adheres to the skin by the application of negative pressure to an annulus surrounding the electrode, which is a bare silver. Data are presented for the factors which govern the adherence to the skin and the range of initial impedance and the values obtained at 2, 5, 10 and 20 minutes and with tap water under the electrodes. The initial impedance is usually high (0.18 to 10 megohms) and decreases progressively with time. Tap water placed under the electrodes dramatically reduces the initial range of impedance. Such electrodes, when used with an amplifier with an adequately high input impedance, can be used for recording electrocardiograms in a variety of situations.