Epicardial Potential Mapping System, The Signal Analysis Method And Heart / Heart Defibrillator's Development

The mechanism research of cardiac electrophysiology and the development of electrical therapy apparatus are two important aspects supplementing each other in the research of arrhythmias. In the aspect of cardiac electrophysiological mechanism research, epicardial potential mapping technology has unique advantage for being with characteristics of exact positioning, large information and in vivo mapping at the same time. One of its technique difficulties is how to analysis the epicardial potential mapping signals effectively and to extract the exact and entire information to explore home the regularities of electrical activations of the heart. In detail it includes 3 aspects: removing interferences, characteristic recognition, information extraction and expression. Moreover "stimulation-mapping" is a very good mean for the research of cardiac electrophysiological mechanism, especially in the exploration of new electrical therapy methods, and the requirement for its stimulation power is high. In the aspect of the development of electrical therapy apparatus for arrhythmias, cardioversion-defibrillation with discharge is a very effective electrical therapy and is important in first-aid occasion out of hospital and long-term therapy. But the development of special cardioverter-defibrillator for heart surgery is lacking very much.This dissertation aimed at the requirements of epicardial potential mapping technology and the special cardioverter-defibrillator for heart surgery. In the aspect of research for epicardial potential mapping signals processing: a new arithmetic for removing interferences was designed based on independent component analysis and the interference independent component selection measurement was the dispersion of independent component' projection coefficients to every electrode; a new characteristic recognition arithmetic based on the information of signal and its B-spline wavelet transform was designed according to the key features of depolarization waveform in epicardial potential mapping signals; the concept of "time-dependence" was put forward and the time-dependent waveform energy analysis was designed based on this concept; the concept of "characteristics" was put forward and the characteristics recognition arithmetic was designed based on short time waveform energy analysis to locate the time window when special depolarization wave traversed the electrodes plaque. A whole automatic united analysis method was designed based on foresaid arithmetic: first to remove interferences in the epicardial potential mapping signals based on independent component analysis; then to recognize characteristic according to signal and its wavelet transform; then to locate the time window when special depolarization wave traversed the electrodes plaque with characteristics recognition arithmetic; in the end to analyze the spread of special depolarization wave unitedly with dynamic iso-potential map, time-dependent waveform energy analysis and isochrones map. In addition, to supply multi-channel electrical stimulator, a DC-DC flyback switch mode power supply based on high performance current mode controller UC3845 was developed according to the requirements of "stimulation-mapping". In the aspect of the development of special cardioverter-defibrillator for heart surgery, aiming at the cardioverter-defibrillator in epicardial and endocardial manner, the development of hardware and program of the whole system included 4 modules: cardioversion-defibrillation main module, impedance detection module, R-wave synchronization module and power supply module. The 4 modules were designed and debugged respectively. And high-voltage circuit was isolated from low-voltage circuit to insure the security. Whereafter R-wave synchronization module was improved on. A new whole-hardware R-wave synchronization circuit based on electrocardiogram and its differential information was designed and a test system based on Labview and DAQ6062E was development to test the performance of the R-wave synchronization circuit.The results of experiments indicated: the new arithmetic based on independent component analysis for removing interferences removed the interferences including non-stationary noises and artifacts in epicardial potential mapping signals effectively and the true depolarization information was reserved and strengthened.; the new characteristic recognition arithmetic based on the information of signal and its B-spline wavelet transform recognized the characteristic in epicardial potential mapping signal accurately; the characteristics recognition arithmetic based on short time waveform energy analysis located the time window when special depolarization wave traversed the electrodes plaque exactly and the subsequent analysis could focus on the spread of special depolarization wave; on this basis, time-dependent waveform energy analysis revealed the spread route of special depolarization wave and the information of depolarization wave was expressed roundly with dynamic iso-potential map and isochrones map; the flyback switch mode power supply could supply enough current during the period of stimulation and keep the stimulation voltage above the threshold value at the same time, and the stimulation voltage could come back rapidly after stimulation; the system aiming at the special cardioverter-defibrillator for heart surgery could charge rapidly to the highest voltage and discharge with biphasic truncated exponential waveform exactly, the discharge of presupposition energy was exact, the measurement of discharge energy was accurate, the impedance detection result was relatively accurate and the impedance classification compensation could be fulfilled; the new R-wave synchronization circuit could locate R-wave automatically and accurately with high positive prediction rate, small delay, low risk and high sensitivity; the test system could output electrocardiogram based on MIT-BIH Arrhythmia Database, observe real-timely and record the R-wave identification result. In conclusion: the whole automatic united analysis method based on arithmetic for removing interference, characteristic recognition arithmetic, characteristics recognition arithmetic, dynamic iso-potential map, time-dependent waveform energy analysis and isochrones map can remove the interferences effectively, recognize the characteristic accurately, locate the time window when special depolarization wave traversed the electrodes plaque exactly and reveal and express the information of depolarization wave roundly, it can help researchers understand the electrical activations in epicardium better and then proceed to the next step to reveal the hidden regularities, so it's fit for the signal processing in epicardial potential mapping system; the flyback switch mode power supply reaches the design requirements and is fit for "stimulation-mapping"; the system aiming at the special cardioverter-defibrillator for heart surgery has the ability to perform cardioversion-defibrillation with discharge in epicardial or endocardial manner in heart surgery; the R-wave synchronization circuit can supply accurate and safe R-wave identification information for cardioverter-defibrillator automatically to support the R-wave synchronization discharge; the test system based on Labview and DAQ6062E makes PC turn into electrocardiogram waveform generator, oscillograph and data recorder at the same time, it improves work efficiency and can be used in other fields expediently. So in the research of arrhythmias, starting with the two aspects of the mechanism research of cardiac electrophysiology and the development of electrical therapy apparatus, some success is obtained in the work and the results have practical significance.