心电散点图在竞争性心律失常分析中的应用

Application of ECG scatterplot in analyzing competitive arrhythmias

目的探讨心电散点图在竞争性心律失常分析中的应用,了解竞争性心律失常的电生理特征,为快速分析动态心电图奠定基础。方法选择常见竞争性心律失常(并行心律、自主心律、逸搏心律、多源性房速)的典型动态心电图病例,分析其心电散点图的形态特征,利用逆向技术并结合动态心电图片断,一窥常见竞争性心律失常的电生理特征。结果并行心律Lorenz散点图的显著特征为右下向斜倒的"Y"字型散点集,表明并行心律自律性并不增高或略有增高,但不超过窦性心律的变异范围,能与窦性心律竞争靠的是其保护性的传入阻滞(对主导心律没有"感知"功能);自主心律的Lorenz散点图特征是室性周期(VV)与联律间期(NV)均重叠在窦律周期(NN)中,表明低位起搏点自律性轻度增高,达到或略超出窦性心律的频率范围,能与窦性心律竞争靠的是"实力"(自律性增高),与窦性心律此起彼伏、反复交替,表明其没有保护性传入阻滞(对主导心律有"感知"功能);逸搏心律的Lorenz散点图特征是等速线远端(1.0 s线之外)的曲尺状上外边界(逸搏夺获节律),表明逸搏心律的自律性没有增高,其节律随时重整,表明没有保护性传入阻滞,由于窦房结或房室结功能障碍,主导心室率降低,故能与主导心律发生低水平的竞争;多源性房速的Lorenz散点图类似房颤的扇图,多个低位起搏点自律性显著增高,几乎取代窦性心律,只有在各级起搏点均传出阻滞的瞬间可能找到少量的窦性心搏,没有固定的节律,表明各低位起搏点之间的竞争势均力敌。结论常见竞争性心律失常的心电散点图特征明显,是快速分析此类动态心电图的秘密武器。心电散点图表现出来的电生理意义(自律性、保护性传入阻滞、间歇性传出阻滞)各不相同,是鉴别与命名的重要依据。

Objective To explore the application of ECG scatterplot in analyzing competitive ar-rhythmias,know its electrophysiological characteristics and lay foundation for rapidly analyzing ambulatory electrocardiography( AECG). Methods Typical AECG cases with common competitive arrhythmias including pararrhythmia,autonomous cardiac rhythm,escaped rhythm and multifocal atrial tachycardia were selected. The morphological features of their ECG scatterplots were analyzed while the electrophysiological characteristics were explored by using the reversal technique and based on AECG segments. Results An obvious feature of the Lorenz scatterplot of pararrhythmia was a Yshaped scatter set which sloped downwards to the right and was upside down. It indicated that the automatic rhythmicity of pararrhythmia did not rise or was slightly higher,not exceeding the variation range of sinus rhythm. By protective entrance block( without "perceptive"function for dominant rhythm),pararrhythmia can compete with sinus rhythm. The Lorenz scatterplot of autonomous cardiac rhythm was characterized by the fact that ventricular cycle( VV) and coupling interval( NV) was overlapping in sinus rhythm cycle( NN). It indicated that the automatic rhythmicity of lower pacemaker was slightly higher,reaching or slightly exceeding the frequency range of sinus rhythm. Autonomous cardiac rhythm competed with sinus rhythm by "strength"( increased automatic rhythmicity). Alternate autonomous cardiac rhythm and sinus rhythm repeated,which suggested there was no protective entrance block( with "perceptive"function for dominant rhythm). The Lorenz scatterplot feature of escaped rhythm was the square-shaped top outer boundary( capture rhythm of escape) at the distal end of constant velocity line( outside the 1. 0 s line). It indicated that the automatic rhythmicity of escaped rhythm did not rise. Its rhythm readjusted at any time,suggesting there was no protective entrance block. Because of reduced dominant ventricular rate resulting from sinus node or atrioventricular nodal dysfunction,escaped rhythm can compete with dominant rhythm at a low level. The Lorenz scatterplot of multifocal atrial tachycardia was similar to the pie chart of atrial fibrillation. The automatic rhythmicity of several lower pacemakers significantly increased,almost replacing sinus rhythm; a small quantity of sinus beats can only possibly be found at the moment of block conduction from pacemakers at all levels; there was no changeless rhythm. It implied that each lower pacemaker was well-matched in strength. Conclusion Common competitive arrhythmias are significantly characterized by ECG scatterplot which serves as a secret weapon for rapidly analyzing these kinds of AECGs. The electrophysiological meanings( including automatic rhythmicity,protective entrance block and intermittent efferent block) reflected by ECG scatterplot vary from each other,which provide important references for identification and nomenclature.