A Digital Timing and Display Unit for Intraoperative Mapping of Cardiac Arrhythmias

An inexpensive display and timing unit incorporating a multichannel signal delay has been developed for mapping the heart during electrophysiological surgery. It provides a continuous digital readout of the time relationships between 3 introcardiac electrograms and the surface electrocordiogram. The electrograms are displayed on a storage oscilloscope with an automatic erase facility. This unit is used to locate accessory atriventricular connections in the Wolff-parkinson-White syndrome, to map ventricular tachycardias and to locate the bundle of His. The design has been refined during 5 years of use in over 200 operative procedures.