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 thirty to fifty Hertz as the timing of the signal is more important and not the morphology.
Prof. Dr. Johnson Francis MD, DM, FACC, FRCP Edin, FRCP London
- Next story FFR to assess need for a side branch stent
- Previous story Reynolds risk score for prediction of coronary artery disease