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