A Device for Automatic Plotting of the Atrioventricular Conduction Time

抄録

For quick and precise measurements of the atrioventricular (AV) conduction time, an AV interval-graph was devised. Atrial and ventricular action potentials in response to right atrial stimulation were picked up differentially. After being mixed, these potentials were reshaped to rectangular pulses by a monostable circuit and finally fed to the Z-axis of a cathode-ray oscilloscope as brightening pulses. The beam of the oscilloscope was swept synchronously with each stimulus pulse and the intensity was adjusted so that bright spots emerged on the oscilloscope screen only when brightening pulses were fed to the Z-axis. With this setup each sweep consisted of an initial spot marking the stimulus artefact followed by two spots corresponding to onset of atrial and ventricular activity so that latency of atrial excitation and AV conduction time could be measured directly.