Cardiac Waveform Monitor
Original Publication Date: 2001-Jan-01
Included in the Prior Art Database: 2003-Jul-22
The extra-stimulus pulse study is a frequently used diagnostic method employed in electrophysiology studies. For this study the heart is electrically stimulated using a drive train of typically eight uniformly spaced pulses followed by a premature or a so-called "extra-stimulus" pulse. The time interval ("coupling interval") between the last pulse of the pulse train and the extra- stimulus pulse is arranged to be shorter than that between pulses of the pulse train. In order to diagnose the condition of the heart the electrophysiologist then monitors the variation in the time- dependent cardiac waveform, generated in response to the applied pulses, as this coupling interval is decreased. Traditionally this monitoring is done by inspecting waveforms in real time on a monitor arranged with a relatively high sweep speed such that one screen width corresponds to approximately 2.5 seconds. This requires the electrophysiologist to constantly change his eye focus as the response will occur at different horizontal screen locations for different cardiac cycles. Moreover, the electrophysiologist is required to remember the shape and location of the spontaneous time- dependent cardiac waveform if its change with coupling interval is to be monitored.