1、,Electrocardiogram,Jiali ZhouDept.Cardiovascular MedicineRenmin Hospital of Wuhan University,心电图纸上的每个小方格，横格为0.04s，纵格为0.1mv。,P波：在肢体导联中除avR为倒置外，余导联多为直立，或较低平,P-R间期：自P波开始至QRS波群开始的时间。正常范围为0.12-0.20s,代表了房室传导时间,QRS波群：时间在0.06-0.10s的狭窄范围内,ST段：是自QRs波群终了的J点开始至T波开始的一段 ，ST段平行的压低或斜向下的压低不正常，轻度抬高可见于正常人,T波：除在avR导联是例
2、置外，余在R波高于0.5mv时均应直立。(如在I，II导联应直立，avR中应倒置，胸前导联自V4-6均直立),Q-T间期：自QRS波开始至T波终了的间期 ,代表心室除极,复极时间的总和,Arrhythmia,Arrhythmia,教学目的、要求 1.了解心律失常分类 2.掌握常见心律失常的心电图表现（窦性心律及窦性心律失常，期前收缩，异位心动过速，心房扑动与心房颤动，房室传导阻滞） 教学难点 常见心律失常的心电图表现,Classification,Abnormal origin-sinus arrhythmia -ectopic rhythm:passivityescapepremature
3、contraction tachycardia flutter and fibrillation Abnormal conduction -physiological block:-pathological block: S-AB; A-VB; LBBB; RBBB-accessory pathway: pre-excitation syndrome,SINUS RHYTHM AND SINUS ARRHYTHMIAS,Sinus rhythm features :,(1) Every P wave is following by a QRS complex; (2) P wave is up
4、right in lead I, II, aVF, V4-V6, inverse in aVR; (3) P-R interval 0.12sec; (4) Difference of P-P interval 0.12sec in the same lead (5) Normal rate is 60-100 beats/min,Sinus Bradycardia:,(1) Sinus rhythm (2) Heart rate 1.0 sec ),Factors associated with sinus bradycardia,(1) Physiologic Laborers and t
5、rained athletesEmotional states leading to syncope (2) Pathologic-blockerHypothyroidism （甲低）,Sinus Tachycardia,(1) Sinus rhythm, rate 100 bpmThe R-R interval (or the P-P interval) 0.60 sec. (2) P-R and Q-T interval are shorter than usual (3) ST-T changes.,Factors associated with sinus tachycardia,(1
6、) PhysiologicExerciseStrong emotion Anxiety states (2) PathologicFeverHemorrhage（出血）Anemia（贫血）Myocarditis（心肌炎）Hyperthyroidism（甲亢）,Sinus arrhythmia,Sinus rhythmDifference of P-P interval 0.12sec in the same lead,Sinus arrest,The P wave missed for a short time,Premature contractions,1. Premature Ventr
7、icular Contraction,(1) Premature QRS complex is the wider and the bizarre , Duration of QRS 0.12 sec. T wave in direction is opposite to QRS complex . (2)Ventricular complex (QRS) is not preceded by a premature P wave. (3) Complete compensatory pause,bigeminy,trigeminy,2. Atrial Premature Contractio
8、ns,(1) The premature P wave differs in contour from the normal P wave in the same lead. (2) The P-R interval 0.12s. (3) There may be a noncompensatory pause.,Tachycardia,1. Paroxysmal supraventricular tachycardia (PSVT),a. Heart rate between 160 250 bpm. b. A precisely regular rhythm with normal QRS
9、.,PSVT,2. Ventricular Tachycardia,a) The rate is 140200/min and the rhythm is very slightly irregular. b) QRS complex is the wider and the bizarre , Duration of QRS 0.12 sec. c) P wave dissociated from QRS;The rate of P wave is less than The rate of QRS d) Ventricular capture ; e) Fusion beats are p
10、resent.,VT,VT,Flutter and Fibrillation,1. Atrial Flutter,(1) Absence of normal P waves; (2) P waves replaced by saw-tooth flutter wave (F waves); (3) Flutter waves seen best in leads II, III,aVF; (4) Regular atrial rhythm with a rate of 250-350 bpm. (5) Ventricular response of 1:1,2:1,3:1,4:1 or hig
11、her,2. Atrial Fibrillation,(1) Absence of clear P waves ; (2) P waves replaced by f waves f waves: irregular in size, shape, best seen in lead V1； (3) Rate of f waves is 350 600 bpm； (4) Irregularly ventricular rate; (5) Generally, duration of QRS complex 0.12sec；,AF,3.Ventricular Flutter and Ventri
12、cular fibrillation,Ventricular flutter: It is impossible to separate the QRS complexes from the ST segment and the T waves Ventricular fibrillation: The ECG shows fine waves that are rapid, and irregular in size, shape, and width .,Conduction Disturbances,1. First Degree A-V Block,Prolonged P-R inte
13、rval:P-R interval 0.20sec in adults,PR=0.36s,2.Second Degree A-V Block,(1) Mobitz type I (Wenckebach phenomenon).The pattern is a progressive prolongation of the P-R interval until a beat is dropped. The first beat after the pause has the shortest P-R interval, which may or may not be normal.,(2) Mo
14、bitz type II,There is a fixed numerical relationship between atrial and ventricular impulses, which may be 2:1 (2 atrial beats to one ventricular beat) or 3:1 or 4:1.,2:1,3.Third Degree A-V Block (Complete heart block),(1) The atrial and the ventricular rhythms are absolutely, independent of one another.(There is no relationship of P to QRS.) (2) atrial rate ventricular rate. (3) Duration of QRS 0.12 sec. or greater.,
