Abstract: According to the present invention there is provided a cardiac diagnosis instrument including an elongated housing, diagnosis electronics accommodated within the housing and two pick-up electrodes mounted on one long side of the housing close to the front and rear ends of the instrument and electrically connected to the diagnosis electronics, a voltage source within the housing, a flat thin graphic display unit which extends along one side for a substantial part of the length of the housing on the opposite side to that on which the pick-up electrodes are located, an on-off switch, said graphic display unit and said on-off switch being electrically connected to the diagnosis electronics, said diagnosis electronics including evaluation electronics and actuation electronics for the graphic display unit, said housing having a tubular shape somewhat like that of a fountain pen, and by placing the housing on a region of the body of a patient, the pick-up electrodes may be pressed into contact with the skin of the p