八道计算机心外膜等时标测系统的建立及实验应用

EIGHT-CHANNEL MICROCOMPUTER-ASSISTEDEPICARDIAL ISOCHRONOUS MAPPINGSYSTEM AND ITS APPLICATION

为了研究致命性心律失常的机理,指导实验和临床探查并消除异位兴奋灶或异常传导路径,我们建立了八道计算机心外膜等时标测系统。系统的硬件由电极、前置放大级、量化级,计算机及输出显示四个部分组成。软件包括前置处理模块、峰值检测模块、时间计算模块、输出显示模块。应用此系统可探查出乌头碱诱发的室速病灶,并指导激光消除病变心肌,转复为窦性心律。

<ABSTRACT> In order to study the mechanism of ventricular tachycardia (VT) and guide Nd: YAG laser photocoagulation on VT foci, we established an eight-channel microcomputer-assisted epicardial isochronous mapping system. Hardware of the system was composed of 4 parts: electrodes, preamplifiers, A/D converter, and microcomputer. 16 pairs of bipolar electrodes made of silver were arranged in 4×4 order and fixed on a squ- are of plexiglass (2 × 2cm2 ). Preamplifier was an eight-channel physiolo- gical record instrument. Signals from 16 pairs of epicardial electrodes (including 1 reference electrode)entered into the instrument in 4 batch- es. Then the signals were amplified and filtered. The resolution of A/D converter is 12 bit. Sampling rate is 600Hz/channel. A microcompu ter is used for digital data analysis. Finally, the isochronous map was shown on the computer terminal or printed on paper. The software included front processing program (FPP ),QRS complex testing program (QRSTP ), analysing program (AP ) and displaying program (DP ). FPP fiitered 50Hz and high frequency noise. QRSTP and AP determined the position of maximal amplitude of QRS complex and calculated epicardial elec- tric activation times. DP showed isochronous map. The programs were written in FORTRAN language and ASSEMBLY language. We successfully found the VT foci in the experiment. After laser photocoagulating the foci, the heart resumed sinus rhythm. Keywords: Local epicardial mapping; Ventricular tachycardia: Isochronal Map Biomcdical Engineering Institute, Chinese Academy of Medical Sciences, Tiaujin, China