New Filtering Approach for Improving Quality of the ECG Signal Recorded During a Non-invasive Electrical Heart Stimulation

J. Gałecka, D. Roj, J. Wróbel, F. Prochaczek, A. Gacek (Inst. of Medical Techn. and Equipment, Poland)

This paper describes a digital filter used in the processing of ECG signal recorded from the esophagus during diagnostic or therapeutic transesophageal cardiostimulation. The interferences from the stimulating pulses have amplitudes exceeding the processing ranges of A/D converters and duration of a few hundred milliseconds. That makes impossible obtaining the required quality of waveforms when using the standard high-pass filters, both analog and digital ones. The proposed Switched Cutoff Frequency filter enables obtaining short responses to distortions occurring in the signal, ensuring the high diagnostic quality of acquired records.