临床诊断学(周蕾)心电图-正常.ppt

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1、心电图Electrocardiogram ECG,南京医科大学第一附属医院 心脏科陈明龙,ECG is an electric curve recorded by ECG recorder from body surface,Basic principles(1),The basis for ECG is the depolarization and repolarization of the myocardial cell,Basic principles(1),Basic principles(2),Basic principles(3),The direction of depolari

2、zation and repolarization is opposite in a single cellThe direction of depolarization and repolarization is the same in ventricular myocardium Depolarization:endocardial pericardial Repolarization:endocardial pericardialThe relationship between electrode position and the direction of depolarization,

3、Basic principles(4),Vector,resultant vectorThe ring of 2-D vectorThe ring of 3-D vector,Resultant Vector,x,a,t,y,The process of ECG formation,Electrode placement and ECG,The electrode connection of the limb leads,Electrode placement and ECG,The three limb leadsEinthoven triangle,Einthoven triangle,E

4、lectrode placement and ECG,The three augmented leads,avR,avL,avF,Electrode placement and ECG,Hexaxial system,Electrode placement and ECG,The precordium leads The additional precordium leads：V7、V8、V9,V3 R、V4R、V5R,Different segments of ECG and their nomenclature,1.P wave 2.P-R segment 3.P-R interval 4

5、.QRS complex 5.ST segment and T wave 6.Q-T interval,Different segments of ECG and their nomenclature,Nomenclature of the components of QRS complex,Different segments of ECG and their nomenclature,Atrial depolarizationposterioranterior，rightleft，upperlower,Different segments of ECG and their nomencla

6、ture,Ventricular depolarization(frontal),Different segments of ECG and their nomenclature,Ventricular depolarization(horizontal),The measurement of ECG,The premise of the measuremet:Paper speed:25mm/s;amplification:1cm=1mv,The measurement of ECG,The measurement of ECG,Heart rate 60/R-R,The measureme

7、nt of ECG,各波段振幅 测量的参考水平：P振幅：P波起始前的水平线 QRS、J、ST、T、U振幅：QRS起始部水平线,The measurement of ECG,The measurement of ECG,各波段时间 12导联同步：P、QRS：最早的P、QRS 起点最晚的终点 P-R：最早的P起点最 早的QRS起点 Q-T：最早的QRS起 点最晚的T终点,The measurement of ECG,非12导联同步：P、QRS：12导联中最宽的 P-R：12导联中P宽大且有Q的导联 Q-T：12导联中最长的 各波时间：内缘内缘,The measurement of ECG,平均心电

8、轴 定义：心室除极过程中全部瞬间向量的综合（平均QRS向量）。借以说明心室在除极过程的总时间内的平均电势强度和方向。,The measurement of ECG,心电轴偏移的意义 影响因素：心脏的解剖位置、左右心室的质量比、心室内传导系统的功能、激动在心室内传导状态、年龄、体型等 心电轴左偏：左心室肥大、左前分支阻滞等 心电轴右偏：右心室肥大、左后分支阻滞等 心电轴的测定：目测法、计算法（测I、III的QRS振幅的代数和）,The measurement of ECG,心脏循长轴转位 正常时V3 或V4的R/S大致相等，为左、右心室过度区波形。顺钟向转位：V5或V6的R/S大致相等右室肥大

9、逆钟向转位：V1或V2的R/S大致相等左室肥大,ECG features of the normal heart,P波：心房除极的电位变化（1）形态：钝圆形，可有轻度切迹,ECG features of the normal heart,P波方向：心脏激动起源于窦房结 心房向量：后前，右左，上下,ECG features of the normal heart,（2）P波时间,ECG features of the normal heart,（3）P波振幅,ECG features of the normal heart,P-R间期：P波起点QRS波起点心房开始除极心室开始除极的时间,正常心率

10、时：0.120.20”老人、心动过缓：可延长至0.22”幼儿、心动过速：可相应缩短,ECG features of the normal heart,QRS波群：心室肌除极的电位变化,ECG features of the normal heart,（1）时间：最宽0.11”,ECG features of the normal heart,（2）波形和振幅 胸导联：波形的变化,R/SV11，R/SV51,ECG features of the normal heart,V1、V2：多呈rS，R V1 1.0mV V3、V4：R与S振幅大致相等V5、V6：可呈qR、qRs、Rs、R，R V5、

11、V6 2.5mV,ECG features of the normal heart,肢导联：,ECG features of the normal heart,I、II、III：QRS主波向上，RI1.5mV aVR：QS、rS、rSr、Qr，R aVR0.5mV aVL、aVF：qR、Rs、R、rS，R aVL1.2mV，R aVF2.0mV 低电压（正向波+负向波）（绝对值）肢导联0.5mV 胸导联0.8mV,ECG features of the normal heart,（3）R峰时间：室壁激动时间，QRS起点至R波顶端垂直线的距离。R峰时间在V1、V2 0.04s，V5、V6 0.0

12、5s,ECG features of the normal heart,（4）Q波：除aVR外,V1、V2无q波，但可呈QS型。,ECG features of the normal heart,J点：QRS波群终末与ST段起始的交接点。,J点位于等电位线上，随ST偏移发生移位J点上移：部分心肌提前复极时发生J点下移：心动过速等原因，心室除极与心房复极并存时发生,ECG features of the normal heart,ST段：QRS波群终点至T波起点，代表心室缓慢复极过程。,ECG features of the normal heart,T波：心室快速复极的电位变化（1）方向：与Q

13、RS主波方向一致 I、II、V4V6 向上 aVR向下 III、aVL、aVF、V1V3向上、双向、向下 V1向上，则V2V6向上,ECG features of the normal heart,（2）振幅：I、II、aVR、V4V6 1/10 R，在胸导联可达1.21.5mV。,ECG features of the normal heart,Q-T间期：QRS波群起点至T波终点，心室肌除极和复极的时间。,Q-T间期受心率影响较大，常采用校正的Q-T间期，表示R-R为1s（心率60次/分）时的Q-T间期，Q-TC=Q-T/（R-R）1/2，不大于0.44s。,ECG features of

14、 the normal heart,U波：T波后0.020.04s出现的振幅很小的波，代表心室后续电位。与T波方向一致。胸导联易见，V3明显，u明显增高见于低血钾。,小儿心电图特点,心率较快，10岁后与成人相同。P-R间期较短，7岁后为0.100.17s，Q-TC较成人略长。P波时限较短（儿童0.09s），电压在新生儿较高，以后较成人低。婴幼儿呈右室优势的QRS图形。I导联深S波 V1（V3R）高R波，V5、V6深S波 V5、V6R波随年龄增加 Q波较深（常见于II、III、aVF）3个月内婴儿，V5、V6无q波 新生儿心电轴+900，以后与成人相同T波变异大，新生儿期，肢体导联和右胸导联T波低平、倒置。,