正常心电图----王兵伟.ppt

* * QRS waveform nomenclature The ECG consists of a small deflection called the P wave, arising from the atria, a more complicated deflection called the QRS complex due to ventricular depolarisation and a final T wave resulting from repolarisation of the ventricles. The QRS complex of waves is the largest deflection of the ECG and is always spiky in shape. All sharp deflections resulting from electrical activation of the ventricles are called QRS complexes. However, these waves can vary immensely in size, and arrangement. The QRS complex is very important when diagnosing myocardial infarction. In order to be able to describe these complexes, a nomenclature for the waves is needed. This can be done using combinations of the letters q, r, s, Q, R, S, lower case letters denoting small waves and upper case larger waves. The first positive wave is labelled with r or R Any second positive wave is labelled r′ or R′ A negative wave which follows an R wave or r wave is labelled S or s A negative wave that precedes an R or r wave, is labelled a q or Q wave Any wave that is entirely negative is labelled qs or QS. Using these rules and nomenclature all QRS complexes can be described, enabling more accurate diagnosis. 心电图基础知识 淮阳楚氏骨科医院 王兵伟 什么是心电图? 心电图(Electrocardiogram, ECG ) 是利用心电图机从体表记录心脏每一心电周期所产生电活动变化的曲线图形。 心电图临床应用范围 主要适应症（能确定诊断） （1）心律失常 （2）心肌梗死 正常传导途径 窦房结 结间束 房室结 左、右束支 房室束 蒲氏纤维 心电图各波的组成与命名及正常值 常规心电图的波形组成和测量示意图 四波：P波、QRS波、 T波、 U波 四段：P-R间期、QRS时间、ST段、Q-T间期 P波—心房除极波 1 窦性P波形态特点 钝圆形，可有轻微切迹。 Ⅰ、Ⅱ、aVF、V3 - V6导联直立，aVR倒置， 其余导联多变（ 双向、低平、直立、倒置）。 正常值 （1）时间： 0.12s （2）峰间距 0.03s； （3）振幅：肢导 0.25mV，胸导 0.20mV。 QRS波—心室除极波，是“生命波” QRS波正常值： （1）R波振幅： V1 ≤ 0.7 mV, V5 ≤ 2.5mV, aVR 0.5 mV, I 1.5 mV, aVL 1.2 mV, aVF 2.0 mV (2）QRS电压：所有肢导联振幅(峰-谷距离或者正向波与负向波振幅的绝对值相加 ) 不能都0.5 mV；所有胸导联振幅不能都 0.8mV。 (3）Q波：除aVR外，振幅同导联R/4，时间0.04s V1, V2不应有