Author/Editor		Gorup, Z; Štajer, D; Rode, P; Gorup, S
Title		An improved PC-based system for high resolution electrocardiography
Type		članek
Source		In: Hamza MH, ed. Modelling, identification and control. 10th IASTED international symposium, Innsbruck 1991: proceedings. Anaheim: Acta press,
Publication year		1991
Volume		str. 269-72
Language		eng
Abstract		Sudden death and cardiac arrhythmias in patients with coronary artery disease can be predicted by registration of late ventricular potentials recorded by high gain signal averaged electrocardiography (SAECG). Low cost and improved quality of personal computers have facilitated development of SAECG based on a PC compatible computer. Signal for SAECG is derived from patients using three bipolar orthogonal precordial leads. It is fed to a three channel low noise battery powered instrumentation amplifier (A = 1000, frequency 1 - 500 Hz), and to an isolation amplifier. The signal is converted into a digital form by a 12 bit A/D PC converter card. An external hardware trigger unit is used for triggering A/D's multiplexer and S/H amplifier. The conversion rate of 10 kHz per channel enables correction of reference point before averaging without loss of high frequency delayed myocardial depolarisation signals. The trigger module as well as software subroutine perform exclusion of noisy and irregular signals. The software applied performs averaging of recordings of number of hearts beats necessary for reduction of noise under 2 microVpp; each consecutive beat is tored on line on a hard disk. The averaged signal is digitally filtered. In order to limit the amount of data stored, temporal resolution is subsequently reduced to 2 kHz. A data base formed from each recording facilitates analysis of patient's SAECG using various conditioning protocols and data storage.
Descriptors		ELECTROCARDIOGRAPHY BIOMEDICAL ENGINEERING ARRHYTMIA VENTRICULAR DYSFUNCTION, LEFT ACTION POTENTIALS AMPLIFIERS NOISE COMPUTERS SOFTWARE