微机心收缩性功能实时分析系统

A Microcomputer System for Real Time Analysis of Myocardial Contractility Indices

本文介绍了一种在IBM-PC/XT微机上开发的心收缩性实时分析系统的软、硬件结构.12位A/D转换器将LVP、BP、ECG信号数字化,采样频率为500Hz.系统软件设计采用菜单选择方式,用8088汇编语言和编译BASIC语言编写.系统按照Maxwell心肌模型,在心脏等容收缩期,测定心肌收缩性能.通过对Maxwell心肌模型的化简,用线性回归方式求出V_(max).系统运行后可绘制或打印出心力环、舒一缩谐调环和dp/dt-P回归线坐标图,打印出反映心肌功能的30项参数及统计分析结果.

A computer-based system for on 條ine real 梩ime analysis of myocardial contractility parameter has been developed using an IBM桺C/XT microcomputer and simple devices. The left ventricular pressure , femoral arterial blood pressure and the ECG wave form are digitized at a sampling rate of 500 Hz by a 12 bit A/D converter. The master program was written in compiler BASIC. The sampling subprogram was written in 8088 assembly language to keep up with the high speed of data acquisition and realtime display.The contractility indices are determined during the isovolumetric period of the LVP. The period is initiated by the peak of the R 梬ave of the ECG and is terminated by the maximum of the derivative of the LVP. After simplification of the Maxwell model by mathematics ,the Vmax can be computed by performing a linear regression between 1/Vce and P. The LVP,BP,ECG,dp/dt curve.cardiac force loop.relaxation -contraction harmoniousness loop and linear regression for determining the Vmax are immediately displayed on CRT console together with 30 contractibility indices after running the program. The system is employed in physiological experiments for evaluation of myocardial contractibility under control conditions ,as well as after drug administration.