对室性早搏“R-on-T”现象的再认识

To Recognize the "R-on-T" Phenomenon of Ventricular Premature Beat

"R-on-T"是一种心电图现象,被认为是过早发生的室性期前收缩落在前一个心动周期易损期,易诱发恶性心律失常。但心电图是时空心肌电总合,该现象在传统观点上结合的是临床与表象,而非本质,不会致恶性心律失常;表象的"R-on-T"本质为"T-to-R",是在心脏异质性增大基础上发生的复极非同步,易发生恶性心律失常,为邻近细胞承接2相动作电位时程差异使3相电压差值增大致易损期细胞再次除极。心肌缺血、缺氧、内环境紊乱及离子通道变异和药物因素等致心脏异质性增大为该现象的发生提供了可能。如何去除诱因,降低心脏异质性,保证心脏复极同步是治疗的关键。

"R-on-T" is a phenomenon of electrocardiogram(ECG)taken as the ventricular extrasystole happened on vulnerable period of cardiac cycle,which can be easily to induce malignant arrhythmia.However,ECG is the integrating of cardiomyocardial electricity in specific time and space and the phenomenon is a combination of the clinical and the appearance rather than the essence:the fusion wave of " R-on-T" cannot cause malignant arrhythmias.But to the appearance of " R-on-T",whose essence is " T-to-R",which based on the increased cardiac heterogeneity causing repolarization non-synchronization and make malignant arrhythmias easily for myocardial cells in supernormal phase excited once more,and the reason is in that adjacent cells undertaking the time difference from 2-phase action potential resulting the voltage difference increasing in 3-phase.Myocardial ischemia,hypoxia,internal environment disorder and the variation of ion channels and drugs and so on contribute to the increase of cardiac heterogeneity.How to remove the inducement and reduce the heterogeneity of the heart is the key to the treatment.