High pass filter settings for surface vs intracardiac electrogram

High pass filter settings for surface vs intracardiac electrogram

High pass filters allow only frequencies above the set limit to pass through and hence eliminate components below a particular frequency. For surface ECG, the high pass filter is set at 0.05 Hertz in order to preserve the T wave and eliminate baseline drift. In case of unipolar intracardiac electrogram, same filter setting is used as the polarity and morphology of the signal are important. In contrast, the high pass filter for bipolar intracardiac electrograms are set at 30 to 50 Hertz as the timing of the signal is more important and not the morphology.