Abstract: Electrocardiographic apparatus including a novel and improved recording paper feed and lead switching arrangement which include a platen having a platen roller, both movable from an open position for installing a supply of recording paper to a position wherein the platen roller with recording paper fed about the surface thereof is moved to an operating position with the platen roller in recording engagement with a recording pen. A paper drive roller is positioned in adjoining relationship to the platen roller and engages the platen roller with the paper thereon when in the operating position. The recording paper is provided with spaced cue marks and transverse perforations between successive cue marks and the apparatus includes a cue detector and associated electric circuitry for detecting said cues so that heart muscle signals from successive groups of patient leads will be recorded on successive segments of the paper defined by the perforations.

Abstract: Electrocardiographic apparatus wherein said apparatus is contained within a wholly insulated enclosure and the recording assembly including writing pens is provided with means for placing an insulating barrier in a position to protect the pens when replenishing the recording paper.