Abstract: A plunge electrode for recording multiple intra-myocardial monophasic action potentials comprises an elongated hollow body with a sharp closed head and an open end and two rows of conductive electrodes provided on opposite sides of the body. One of the electrodes are soldered electrodes and the others are moveable electrodes. The plunge also comprises an adjusting device for adjusting the moveable electrodes between a first position where the moveable electrodes are protruded out of the wall of the body and a second position where the moveable electrode are retracted within the body. Two bundles of conductive wires are respectively connected to said electrodes for transmission of recorded signals.