Assessment of the fidelity of pacemaker telemetric signals

To monitor the changes of the signals sensed by the pacemaker (PM) during the lifetime of the device, one has to know exactly how faithfully the telemetric atrial and ventricular electrograms (EGMs) reproduce the direct EGMs, the former being the only available signals after implantation. Here, the authors describe the methodology they developed to assess the fidelity of telemetric signals. They tested the proposed procedure on 8 patients carrying the same type of pacemaker with atrial sensing and 3 with ventricular sensing (Medtronic Elite 7077/7086). Some frequency and time domain parameters were computed on direct and telemetric signals and compared. The authors' methodology proved to be very simple and effective in the assessment of the PM telemetry system performance, showing that the whole system from the PM's input to the telemetry output behaves like a linear lowpass filter with a -3dB frequency at about 100 Hz. As most of the power of the signals to be sensed is below 50 Hz, it is concluded that telemetric signals can be considered faithful replica of the true electrograms.<
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