The examination and recording of the human electrocardiogram by means of the cathode-ray oscillograph

The cathode-ray oscillograph, having no inherent inertia and yet being comparatively indestructible, is an instrument peculiarly suitable for everyday electrocardiography. A fluorescent screen of very long afterglow enables the electrocardiogram to be examined directly at the patient´s bedside, which is a new facility. The design of the amplifier has to be adapted to the peculiarities of the heart-action voltages and electrical constants of the patient; these are considered in some detail, and practical methods for the examination´ of the adequacy of the amplifier are discussed. The provision of a high-voltage supply suitable for any eventuality is considered, together with methods of obviating interference, especially from alternating-current mains.