PC based high resolution ECG system

A PC-based high-resolution electrocardiography system is developed. The system consists of an add-on card, a computer and a printer. The add-on card has all the analog and digital circuits needed for data acquisition. Bipolar X, Y, Z signals are first acquired to RAM without any interruption and then transferred to disc. Two-Mbyte RAM is required for uninterrupted 2.5-minute raw data to be collected. An operator-controlled template selection is followed by signal averaging, high-pass filtering (25-250 Hz) and calculation of Simson's criteria for detection of late potentials. It is shown that terminal portion of the QRS can be modeled as sum of decaying sinusoids with less than 25-Hz frequency. When this model signal is estimated and subtracted from the QRS signals, higher-frequency (25-250 Hz) activity is much better isolated both in the time and the frequency domains.<
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